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Cancer cells exhibit altered glucose metabolism characterized by a preference for aerobic glycolysis or the Warburg effect , and the cells resist matrix detachment-induced apoptosis , which is called anoikis , a barrier to metastasis . It remains largely unclear whether tumor metabolism influences anoikis and metastasis . Here we show that when detached from the matrix , untransformed mammary epithelial cells undergo metabolic reprogramming by markedly upregulating pyruvate dehydrogenase ( PDH ) kinase 4 ( PDK4 ) through estrogen-related receptor gamma ( ERR\u03b3 ) , thereby inhibiting PDH and attenuating the flux of glycolytic carbon into mitochondrial oxidation . To decipher the significance of this metabolic response , we found that depletion of PDK4 or activation of PDH increased mitochondrial respiration and oxidative stress in suspended cells , resulting in heightened anoikis . Conversely , overexpression of PDKs prolonged survival of cells in suspension . Therefore , decreased glucose oxidation following cell detachment confers anoikis resistance . Unlike untransformed cells , most cancer cells demonstrate reduced glucose oxidation even under attached conditions , and thus they inherently possess a survival advantage when suspended . Normalization of glucose metabolism by stimulating PDH in cancer cells restores their susceptibility to anoikis and impairs their metastatic potential . These results suggest that the Warburg effect , more specifically , diminished glucose oxidation , promotes anoikis resistance and metastasis and that PDKs are potential targets for antimetastasis therapy .
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22431524
|
To assess the immune function of microglia and macrophages in brain tumors , the expression of MHC class II and B7 costimulatory molecules in three rodent glioma models was examined . Microglia and macrophages , which accounted for 5-12% of total cells , expressed B7.1 and MHC class II molecules in the C6 and 9L tumors , but not RG2 gliomas . Interestingly , the expression of B7.1 and MHC class II molecules by microglia and macrophage was associated with an increase in the number of tumor-infiltrating lymphocytes in C6 and 9L tumors . B7.2 expression , which was present at low levels on microglia and macrophages in normal brain , did not significantly change in tumors . Interestingly , the expression of all three surface antigens increased after microglia were isolated from intracranial C6 tumors and cultured for a short period of time . We conclude that microglia immune activity may be suppressed in gliomas and directly correlates to the immunogenecity of experimental brain tumors .
|
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12446006
|
By intravenous ( but not oral ) application of ascorbate , millimolar serum concentrations can be reached , which are preferentially cytotoxic to cancer cells . Cytotoxicity is mediated by transition metal-dependent generation of H(2)O(2) in the interstitial space . In this study , the sensitivity of neuroblastoma cells ( Kelly , SK-N-SH ) to ascorbate and H(2)O(2) and their defense mechanisms against H(2)O(2) were investigated . Since aerobic glycolysis ( the Warburg effect ) is a feature of many tumour cells , their glucose consumption and lactate production were monitored . Furthermore , synthesis and release of ferritin by neuroblastoma cells were analysed in order to examine whether ferritin is possibly an iron source for H(2)O(2) generation . Ascorbate ( 0.6-5.0 mM ) and H(2)O(2) ( 25-100 muM ) were found to be similarly cytotoxic to Kelly and SK-N-SH cells . In each case , cytotoxicity increased if cell concentrations decreased , in accordance with low cell concentrations having lower capacities to detoxify H(2)O(2) . Kelly and SK-N-SH cells produced and released remarkable amounts of lactate and ferritin . We propose the selective cytotoxicity of high dose ascorbate to tumour cells to be due to the preferential generation of H(2)O(2) in the acidic and ferritin-rich tumour microenvironment , combined with reduced defense systems against H(2)O(2) as a consequence of aerobic glycolysis .
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20511723
|
Binding within or nearby target genes involved in cell proliferation and survival enables the p53 tumor suppressor gene to regulate their transcription and cell-cycle progression . Using genome-wide chromatin-binding profiles , we describe binding of p53 also to regions located distantly from any known p53 target gene . Interestingly , many of these regions possess conserved p53-binding sites and all known hallmarks of enhancer regions . We demonstrate that these p53-bound enhancer regions ( p53BERs ) indeed contain enhancer activity and interact intrachromosomally with multiple neighboring genes to convey long-distance p53-dependent transcription regulation . Furthermore , p53BERs produce , ina p53-dependent manner , enhancer RNAs ( eRNAs ) that are required for efficient transcriptional enhancement of interacting target genes and induction of a p53-dependent cell-cycle arrest . Thus , our results ascribe transcription enhancement activity to p53 with the capacity to regulate multiple genes from a single genomic binding site . Moreover , eRNA production from p53BERs is required for efficient p53 transcription enhancement .
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23273978
|
Osteopontin ( OPN ) , which is highly expressed in malignant glioblastoma ( GBM ) , possesses inflammatory activity that is modulated by proteolytic cleavage by thrombin and plasma carboxypeptidase B2 ( CPB2 ) at a highly conserved cleavage site . Full length OPN ( OPN-FL ) was elevated in cerebrospinal fluid ( CSF ) samples from all cancer patients compared to non-cancer patients . However thrombin-cleaved OPN ( OPN-R ) and thrombin/CPB2-double cleaved OPN ( OPN-L ) levels were markedly increased in GBM and non-GBM gliomas compared to systemic cancer and non-cancer patients . Cleaved OPN constituted and of the total OPN in the GBM and non-GBM CSF samples respectively . OPN-R was also elevated in GBM tissues . Thrombin-antithrombin levels were highly correlated with cleaved OPN , but not OPN-FL , suggesting that the cleaved OPN fragments resulted from increased thrombin and CPB2 in this extracellular compartment . Levels of VEGF and CCL4 were increased in CSF of GBM and significantly correlated with the levels of cleaved OPN . GBM cell lines were significantly more adherent to OPN-R and OPN-L than OPN-FL . Adhesion to OPN altered gene expression , in particular genes involved with cellular processes , cell cycle regulation , death and inflammation . OPN promoted motility of U-87 MG cells and conferred resistance to apoptosis . While functional mutation of the RGD motif in OPN largely abolished these functions , OPN(RAA)-R regained significant cell binding and signaling function , suggesting that the SVVYGLR motif in OPN-R may substitute for the RGD-motif if the latter becomes inaccessible . OPN cleavage contributes to GBM development by allowing more cells to bind in niches in which they acquire anti-apoptotic properties .
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23204518
|
A novel camptothecin derivative ( TLC388 ) with higher efficacy and reduced toxicity has been synthesized and tested as a novel chemoradiosensitizing agent . This study investigated the mechanisms of the chemoradiosensitizing effects of TLC388 on H23 human non-small cell lung cancer ( NSCLC ) cells . Using the TUNEL assay , a significantly higher percentage of apoptotic cells was observed in the group treated with TLC388 plus X-ray radiation than those in groups treated with drug or radiation alone . The sensitizer enhancement ratio ( SER ) was 1.91 . Apoptosis increased with drug concentration and radiation dose , exhibiting dose-dependent pattern . The results suggested that apoptosis could be a main mode of cell death that might underlie the increased chemoradio-sensitization of TLC388 . Treatment with 30 nM of TLC388 plus 4 Gy X-ray also produced up to 42% of necrotic cells that were measured by trypan blue exclusion assay , but with TLC388 alone or 4 Gy radiation alone 9.8% or 11.1% necrotic cells were detected , respectively . An immunofluorescent staining method was employed to determine the levels of gamma-H2AX ( phosphorylated H2AX , a variant of the H2A protein family , which is a component of the histone octomer in nucleosomes and is phosphorylated by kinases like ATM and ATR in the PI3K pathway , as the first step in recruiting and localizing DNA repair proteins ) as a molecular biomarker of DNA double strand breaks ( DSBs ) in cells treated with TLC388 +/-radiation , or radiation alone . The formation of gamma-H2AX foci was observed after TLC388 or radiation exposure and when the cells were treated with 30 nM TLC388 plus radiation at a dose of 2 Gy , the percentage of cells containing gamma-H2AX foci increased significantly . Even more interesting , a markedly higher percentage ( 65.4% ) of mitotic cells displayed gamma-H2AX foci after treatment with 30 nM TLC388 plus 0.5 Gy radiation , compared to only 5.9% or 26.1% of the M-phase cells treated with 30 nM TLC388 alone or 0.5 Gy radiation alone , respectively . It is suggested that mitotic cells become very sensitive to the production of DSBs after TLC388-radiation combined treatment and the formation of DSBs is strongly suggested to lead to the induction of apoptosis at doses lower than 4 Gy and to some necrosis at doses of 4 Gy or above . TLC388 enhances the production of DSBs and inhibits their repair , which contributes to the elucidation of the mechanisms of chemoradiosensitization of TLC388 and its development as a novel chemoradiosensitizing drug for improved radiotherapy .
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20393017
|
Gamma-radiation , tetrandrine , bistratene A , and cisplatin were all found to induce pronounced morphological changes characteristic of apoptosis and extensive DNA fragmentation in the human BM13674 cell line 8 h after treatment . Apoptosis induced in BM13674 cells by these diverse agents was markedly inhibited by 1 microM okadaic acid , a tumour promoter that inhibits protein phosphatases 1 and 2A . This compound also inhibited the appearance of apoptosis in fresh human leukaemia cells that had been exposed to gamma-radiation . The inhibition of apoptosis was confirmed using fluorescence microscopy and DNA gel electrophoresis . Dephosphorylation of a limited number of proteins was shown to be associated with apoptosis and okadaic acid prevented these dephosphorylations . Previous studies on the BM13674 cell line showed that an inhibitor of protein synthesis failed to prevent apoptosis in these cells . The present data provides further support that posttranslational modification of proteins , in particular , phosphorylation/dephosphorylation status , plays an important role in inhibition/activation of programmed cell death in different human cells after exposure to several cytotoxic agents .
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1447316
|
The mammalian COP9 signalosome ( CSN ) complex is involved in cell transformation , but its molecular mechanism remains undetermined . Here we show that disruption of the fifth component ( CSN5 ) prevented the formation of tumors by p53-null cells transformed with an active form of Ras in subcutaneously injected mice . Depletion of CSN5 suppressed cell proliferation , and induced premature senescence characterized by upregulation of senescence-associated-β-galactosidase activity and increased expression of CDK inhibitors . CSN5-depleted cells exhibited enhanced activation of the PI3 kinase-Akt pathway , and chemical inhibition of this pathway reduced the level of senescence . Thus , CSN5 is suggested to be a novel target in cancer therapy and for drugs against tumor cells harboring mutated p53 .
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23127558
|
We found that the human colon cancer cell line SW480 consists of two distinct subpopulations which we have designated E-type ( epithelial ) and R-type ( round ) . Pure cultures of each type were obtained by subcloning , and both have maintained their characteristic phenotypes for at least 1 year ( 40 passages ) . E-type cells are the major ( > 98% ) type in the parental SW480 cell line . They form flat epithelial-like colonies . In contrast , R-type cells , which constitute a minor fraction ( < 2% ) of the parental cell line , have a rounded shape and grow in clusters of piled-up cells . Compared to E-type cells or the parental SW480 cells , isolated R-type cells display decreased doubling time , loss of contact inhibition , less adhesiveness to culture plates , higher anchorage-independent growth in soft agar , and a much more aneuploid karyotype . When injected s.c. into nude mice , R-type cells produce much larger tumors within the same period of time than E-type cells , and the tumors are less differentiated than those produced by the E-type cells . Cell fusion experiments between R-type and E-type cells revealed that the R-type phenotype is dominant , and the results suggest that this is due to one or a few genetic changes . Taken together , these findings suggest that the R-type cells represent a more malignant variant of the E-type cells . They may be useful , therefore , for studying mechanisms involved in tumor progression .
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1458472
|
Genomic instability drives tumorigenesis , but how it is initiated in sporadic neoplasias is unknown . In early preneoplasias , alterations at chromosome fragile sites arise due to DNA replication stress . A frequent , perhaps earliest , genetic alteration in preneoplasias is deletion within the fragile FRA3B/FHIT locus , leading to loss of Fhit protein expression . Because common chromosome fragile sites are exquisitely sensitive to replication stress , it has been proposed that their clonal alterations in cancer cells are due to stress sensitivity rather than to a selective advantage imparted by loss of expression of fragile gene products . Here , we show in normal , transformed , and cancer-derived cell lines that Fhit-depletion causes replication stress-induced DNA double-strand breaks . Using DNA combing , we observed a defect in replication fork progression in Fhit-deficient cells that stemmed primarily from fork stalling and collapse . The likely mechanism for the role of Fhit in replication fork progression is through regulation of Thymidine kinase 1 expression and thymidine triphosphate pool levels ; notably , restoration of nucleotide balance rescued DNA replication defects and suppressed DNA breakage in Fhit-deficient cells . Depletion of Fhit did not activate the DNA damage response nor cause cell cycle arrest , allowing continued cell proliferation and ongoing chromosomal instability . This finding was in accord with in vivo studies , as Fhit knockout mouse tissue showed no evidence of cell cycle arrest or senescence yet exhibited numerous somatic DNA copy number aberrations at replication stress-sensitive loci . Furthermore , cells established from Fhit knockout tissue showed rapid immortalization and selection of DNA deletions and amplifications , including amplification of the Mdm2 gene , suggesting that Fhit loss-induced genome instability facilitates transformation . We propose that loss of Fhit expression in precancerous lesions is the first step in the initiation of genomic instability , linking alterations at common fragile sites to the origin of genome instability .
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23209436
|
Estrogen affects apoptotic cell death in estrogen-responsive tissues . The purpose of the present study was to examine dynamic changes in apoptotic cell death in the anterior pituitary gland during the estrous cycle and to investigate neuroendocrine regulation of these changes in cycling female rats . Terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling ( TUNEL ) for in situ detection of DNA strand breaks revealed that the number of TUNEL-positive anterior pituitary cells was changing during the estrous cycle , with a maximum in the morning of proestrus and a minimum in the morning of estrus . A similar pattern was observed with Bax immunostaining ; however , no difference was observed in Bcl-2 immunostaining . Most of Bax-immunoreactive cells were identified as a subpopulation of gonadotropes . Pentobarbital administered in the afternoon of proestrus attenuated the decrease in TUNEL-positive or Bax-immunoreactive cells in the morning of estrus , although estradiol treatment failed to affect it . This action of pentobarbital was reduced by simultaneous treatment with an ovulation-inducing dose of gonadotropin-releasing hormone ( GnRH ) , but not with progesterone , an ovarian steroid also released after GnRH treatment . These results suggest that anterior pituitary cells , mostly gonadotropes , undergo a cyclic change in apoptotic cell death during the estrous cycle and that the inhibition of apoptosis on estrus is due , at least in part , to the proestrous surge of GnRH secretion .
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12457038
|
Epidemiological studies exploring the connection between hypertension and cancer incidence find a higher cancer mortality in hypertensive patients , particularly elevated in hypertension associated with a stimulation of the renin-angiotensin-aldosterone system . Primary aldosteronism , with plasma aldosterone levels between 0.5 and 1 nM ( 18-36 ng/dL ) and local aldosterone levels up to 500 nM ( 18,000 ng/dL ) , is now recognised as a more common cause for hypertension . We recently found angiotensin II to be genotoxic due to its induction of oxidative stress . Since aldosterone in higher concentrations also has oxidative effects , its potential genotoxic action in pig LLC-PK1 cells with properties of proximal tubules was analysed . DNA damage was evaluated by two test systems : the comet assay , and the micronucleus frequency test . The results showed that aldosterone concentrations starting from 10 nM ( 360 ng/dL ) caused a significant increase of DNA damage monitored with the comet assay in LLC-PK1 , while there was no change in cell vitality and proliferation . The micronucleus frequency test revealed that 10 nM aldosterone also leads to the formation of micronuclei . Furthermore , the formation of superoxide radicals in the cells by this aldosterone concentration could be detected with the superoxide-specific stain dihydroethidium . Further evidence for oxidative stress-induced DNA damage was its reversibility by the antioxidants tempol and catalase . Addition of the steroidal mineralocorticoid receptor antagonist spironolactone or the novel selective nonsteroidal antagonist ( R)-BR-4628 reduced the DNA damage and the amount of superoxide radicals indicating a receptor-dependent process .
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20094972
|
Polycyclic aromatic hydrocarbons ( PAHs ) are widely distributed immunotoxic and carcinogenic environmental contaminants , known to affect macrophages . In order to identify their molecular targets in such cells , we have analyzed gene expression profile of primary human macrophages treated by the prototypical PAH benzo(a)pyrene ( BaP ) , using pangenomic oligonucleotides microarrays . Exposure of macrophages to BaP for 8 and 24 h resulted in 96 and 1100 genes , differentially expressed by at least a twofold change factor , respectively . Some of these targets , including the chemokine receptor CXCR5 , the G protein-coupled receptor 35 ( GPR35 ) , and the Ras regulator RASAL1 , have not been previously shown to be affected by PAHs , in contrast to others , such as interleukin-1beta and the aryl hydrocarbon receptor ( AhR ) repressor . These BaP-mediated gene regulations were fully validated by reverse transcription-quantitative polymerase chain reaction assays for some selected genes . Their bioinformatic analysis indicated that biological functions linked to immunity , inflammation , and cell death were among the most affected by BaP in human macrophages and that the AhR and p53 signaling pathways were the most significant canonical pathways activated by the PAH . AhR and p53 implications were moreover fully confirmed by the prevention of BaP-related upregulation of some selected target genes by AhR silencing or the use of pifithrin-alpha , an inhibitor of PAH bioactivation-related DNA damage/p53 pathways . Overall , these data , through identifying genes and signaling pathways targeted by PAHs in human macrophages , may contribute to better understand the molecular basis of the immunotoxicity of these environmental contaminants .
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20064835
|
Colorectal cancer ( CRC ) arises as the consequence of progressive changes from normal epithelial cells through polyp to tumor , and thus is an useful model for studying metabolic shift . In the present study , we studied the metabolomic profiles using high analyte specific gas chromatography/mass spectrometry ( GC/MS ) and liquid chromatography tandem mass spectrometry ( LC/MS/MS ) to attain a systems-level view of the shift in metabolism in cells progressing along the path to CRC . Colonic tissues including tumor , polyps and adjacent matched normal mucosa from 26 patients with sporadic CRC from freshly isolated resections were used for this study . The metabolic profiles were obtained using GC/MS and LC/MS/MS . Our data suggest there was a distinct profile change of a wide range of metabolites from mucosa to tumor tissues . Various amino acids and lipids in the polyps and tumors were elevated , suggesting higher energy needs for increased cellular proliferation . In contrast , significant depletion of glucose and inositol in polyps revealed that glycolysis may be critical in early tumorigenesis . In addition , the accumulation of hypoxanthine and xanthine , and the decrease of uric acid concentration , suggest that the purine biosynthesis pathway could have been substituted by the salvage pathway in CRC . Further , there was a step-wise reduction of deoxycholic acid concentration from mucosa to tumors . It appears that to gain a growth advantage , cancer cells may adopt alternate metabolic pathways in tumorigenesis and this flexibility allows them to adapt and thrive in harsh environment .
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20147338
|
Nowadays , tobacco smoking is the cause of million deaths per year , counting 31% and 6% of all cancer deaths ( affecting 18 different organs ) in middle-aged men and women , respectively . Nicotine is the addictive component of tobacco acting on neuronal nicotinic receptors ( nAChR ) . Functional nAChR , are also present on endothelial , haematological and epithelial cells . Although nicotine itself is regularly not referred to as a carcinogen , there is an ongoing debate whether nicotine functions as a ' tumour promoter ' . Nicotine , with its specific binding to nAChR , deregulates essential biological processes like regulation of cell proliferation , apoptosis , migration , invasion , angiogenesis , inflammation and cell-mediated immunity in a wide variety of cells including foetal ( regulation of development ) , embryonic and adult stem cells , adult tissues as well as cancer cells . Nicotine seems involved in fundamental aspects of the biology of malignant diseases , as well as of neurodegeneration . Investigating the biological effects of nicotine may provide new tools for therapeutic interventions and for the understanding of neurodegenerative diseases and tumour biology .
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22050423
|
Cancer immunoediting is the process whereby immune cells protect against cancer formation by sculpting the immunogenicity of developing tumors . Although the full process depends on innate and adaptive immunity , it remains unclear whether innate immunity alone is capable of immunoediting . To determine whether the innate immune system can edit tumor cells in the absence of adaptive immunity , we compared the incidence and immunogenicity of 3'methylcholanthrene-induced sarcomas in syngeneic wild-type , RAG2(-/-) , and RAG2(-/-)x γc(-/-) mice . We found that innate immune cells could manifest cancer immunoediting activity in the absence of adaptive immunity . This activity required natural killer ( NK ) cells and interferon γ ( IFN-γ ) , which mediated the induction of M1 macrophages . M1 macrophages could be elicited by administration of CD40 agonists , thereby restoring editing activity in RAG2(-/-)x γc(-/-) mice . Our results suggest that in the absence of adaptive immunity , NK cell production of IFN-γ induces M1 macrophages , which act as important effectors during cancer immunoediting .
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22927549
|
Ferric nitrilotriacetate ( Fe-NTA ) is a potent nephrotoxicant and a renal carcinogen that induces its effect by causing oxidative stress . The present study was undertaken to explore protective effect of silymarin , a flavonolignan from milk thistle ( Silybum marianum ) , against Fe-NTA mediated renal oxidative stress , inflammation and tumor promotion response along with elucidation of the implicated mechanism(s) . Administration of Fe-NTA ( 10 mg/kg bd wt , i.p. ) to Swiss albino mice induced marked oxidative stress in kidney , evident from augmentation in renal metallothionein ( MT ) expression , depletion of glutathione content and activities of antioxidant and phase II metabolizing enzymes , and enhancement in production of aldehyde products such as 4-hydroxy-2-nonenal . Fe-NTA also significantly activated nuclear factor kappa B ( NFkappaB ) and upregulated the expression of downstream genes : cyclooxygenase 2 and inducible nitric oxide synthase and enhancing the production of proinflammatory cytokines : tumor necrosis factor alpha ( TNF-alpha ) and interleukin-6 ( IL-6 ) . However , feeding of 0.5% and 1% silymarin diet conferred a significant protection against Fe-NTA induced oxidative stress and inflammation . It further augmented MT expression , restored the antioxidant armory , ameliorated NFkappaB activation and decreased the expression of proinflammatory mediators . Silymarin also suppressed Fe-NTA induced hyperproliferation in kidney , ameliorating renal ornithine decarboxylase activity and DNA synthesis . From these results , it could be concluded that silymarin markedly protects against chemically induced renal cancer and acts plausibly by virtue of its antioxidant , anti-inflammatory and antiproliferative activities .
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19590824
|
Inflammatory events have been associated with senile plaques , one of the pathological hallmarks of Alzheimer's disease ( AD ) . It is believed that aggregated beta-amyloid ( betaA ) proteins , which form the core of these plaques , may be responsible for triggering the inflammatory reaction . In the present study , the ability of aluminum ( Al ) to initiate similar inflammatory events was investigated in a human glioblastoma cell line . A 6-day exposure to either lipopolysaccharide ( LPS ) or aluminum sulfate caused a significant increase in the rate of proliferation of the glioblastoma cells . Both treatments also caused activation of the immune-responsive transcription factor NF-kappaB although there were time-related differences . The levels of secreted cytokines , interleukin-6 ( IL-6 ) and tumor necrosis factor alpha ( TNF-alpha ) were both increased by the LPS treatment although exposure to Al decreased the secretion of the former while elevating the levels of the latter . These events may be due to the activation of glial cells and subsequent stress response to either Al complexes or LPS . Although exposure to either stress factor caused a stimulation of inflammatory markers , there were time-dependent differences in the response . This may reflect the ability of the cells to discern different stress factors and thus orchestrate an innate immune response profile distinct to each immunogen .
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11929636
|
The aim of this study was to extend our previous observations on the soy modulation of biochemical parameters in 7,12-dimethylbenz[a]anthracene ( DMBA)-induced rat mammary tumors , by simultaneously investigating the expression of estrogen receptor-alpha ( ERalpha ) , estrogen receptor-beta ( ERbeta ) , progesterone receptor ( PR ) , apoptosis , neu , and markers of cell proliferation , such as proliferating cell nuclear antigen ( PCNA ) by immunohistochemistry . The percentage of ERalpha positive tumors was 65.8% in masses from control animals , and significantly dropped to 36.8% in tumors from soy treated rats ( P=0.010 ) . The percentage of ERbeta positive tumors was 70.3% in masses from control animals vs. 50.0% in tumors from soy exposed animals ( P=0.066 ) . Moreover , the percentage of cases which were both ERalpha and ERbeta positive was significantly lower ( 17.6% ) in soy treated than in control animals ( 51.3% ) ( P=0.006 ) . The percentage of PR positive tumors was 34.2% in control animals vs. 2.6% in tumors from soy treated rats ( P=0.0006 ) . There were no statistically significant differences in the percentage of tumors positively stained for neu , apoptosis , or PCNA , in control vs. soy treated rats . However , when analyzing the reciprocal correlation among the different biochemical parameters we showed that , in treated animals , the majority of ERalpha positive tumors ( 91.7% ) were also PCNA positive ( P=0.036 ) . The median percentage of PCNA positivity was significantly higher in ERalpha positive than in ERalpha negative tumors ( 25 vs. 5% ) ( P=0.0031 ) . Moreover , an association was found between PCNA and neu status since all neu positive tumors were also PCNA positive ( P=0.011 ) .
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12183074
|
MG132 , as a proteasome inhibitor , can induce apoptotic cell death through formation of reactive oxygen species ( ROS ) . In this study , we investigated the effects of MAPK ( MEK , JNK , and p38 ) inhibitors on MG132-treated A549 lung cancer cells in relation to cell growth , cell death , ROS , and glutathione ( GSH ) levels . Treatment with 10 microM MG132 inhibited the growth of A549 cells at 24 h . MG132 also induced apoptosis , which was accompanied by the loss of mitochondrial membrane potential ( MMP ; deltapsi(m) ) . ROS were not increased in MG132-treated A549 cells . MG132 increased GSH-depleted cell numbers and decreased GSH levels . MEK and JNK inhibitors did not strongly affect cell growth , cell death , ROS , and GSH levels in MG132-treated A549 cells . In contrast , p38 inhibitor reduced cell growth inhibition , apoptosis , and MMP ( deltapsi(m) ) loss by MG132 . However , p38 inhibitor did not change ROS level and GSH content . In conclusion , MG132 inhibited the growth of A549 cells via apoptosis without formation of ROS . Treatment with p38 inhibitor rescued some cells from MG132-induced apotposis , which was not affected by ROS and GSH level changes .
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20377132
|
Jaceosidin , a flavonoid derived from Artemisia princeps ( Japanese mugwort ) , has been shown to inhibit the growth of several human cancer cells , However , the exact mechanism for the cytotoxic effect of jaceosidin is not completely understood . In this study , we investigated the molecular mechanism involved in the antiproliferative effect of jaceosidin in human endometrial cancer cells . We demonstrated that jaceosidin is a more potent inhibitor of cell growth than cisplatin in human endometrial cancer cells . In contrast , jaceosidin-induced cytotoxicity in normal endometrial cells was lower than that observed for cisplatin . Jaceosidin induced G2/M phase cell cycle arrest and modulated the levels of cyclin B and p-Cdc2 in Hec1A cells . Knockdown of p21 using specific siRNAs partially abrogated jaceosidin-induced cell growth inhibition . Additional mechanistic studies revealed that jaceosidin treatment resulted in an increase in phosphorylation of Cdc25C and ATM-Chk1/2 . Ku55933 , an ATM inhibitor , reversed jaceosidin-induced cell growth inhibition , in part . Moreover , jaceosidin treatment resulted in phosphorylation of ERK , and pretreatment with the ERK inhibitor , PD98059 , attenuated cell growth inhibition by jaceosidin . These data suggest that jaceosidin , isolated from Japanese mugwort , modulates the ERK/ATM/Chk1/2 pathway , leading to inactivation of the Cdc2-cyclin B1 complex , followed by G2/M cell cycle arrest in endometrial cancer cells .
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23274058
|
5-HT1c receptors have been shown to act as protooncogenes in NIH 3T3 cells , inducing ligand-dependent focus formation . In order to assess their mitogenic and oncogenic potential in a different cell system , we transfected these receptors into CCL39 hamster fibroblasts , a well-characterized growth factor-dependent cell line . Cell clones expressing functional receptors were isolated and tested for ( a ) growth factor dependence of proliferation measuring thymidine incorporation in response to varying doses of serum , ( b ) the response to serotonin alone or in combination with other growth factors , and ( c ) the capacity for anchorage-independent proliferation . In the absence or presence of serotonin , the large majority of the clones isolated showed normal morphology and normal growth factor dependence and was unable to grow in soft agar . None of the clones showed a significant response to serotonin alone in DNA synthesis reinitiation experiments , but synergy was observed between serotonin and the tyrosine kinase activating growth factors EGF and FGF . However , the major part of this effect could be abolished by an antagonist of 5-HT1b receptors , which are endogenous in CCL39 cells . The same receptor was found to mediate a significant mitogenic response to the neurotransmitter in Ha-ras-transfected cells . The fact that 5-HT1c receptors do not readily induce a transformed phenotype in CCL39 cells clearly distinguishes them from strong dominantly acting oncogene products like RAS , SRC , or FMS .
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1315291
|
The mouse polyomavirus encodes a tumor-suppressor gene inactivator in its large T protein and a proto-oncogene activator in its middle T protein . We have used site-directed mutagenesis to selectively inactivate the former function without affecting the latter . Two mutant viruses were constructed to encode altered large T proteins that fail to bind the retinoblastoma tumor-suppressor gene product pRB , along with normal small and middle T proteins . The pRB-binding mutants proved to be defective in immortalization of primary rat embryo fibroblasts by a variety of tests . Yet they proved capable of transforming both primary and established fibroblasts in culture . Most importantly , the inability of these mutants to bind pRB had little effect on their ability to induce tumors in mice . We conclude that induction of multiple tumor types in this system does not depend on large T-pRB interactions but rather on middle T-dependent pathways . In addition , the ability of this virus to immortalize cells in culture is not essential to its ability to induce tumors in the animal .
|
[
0,
0,
0,
1,
0,
0,
0,
0,
0,
0
] |
1328987
|
p107 Links to cyclin A/CDK2 ( cyclin-dependent kinase 2 ) and cyclin E/CDK2 that are important cell cycle regulators . However , p107 expression remains unclear in almost all kinds of human solid tumours . To clarify the expression of p107 in colorectal tumours , 22 normal mucosae , 9 hyperplastic polyps , 60 adenomas , 198 primary carcinomas , 21 lymph-nodal metastases , and 10 hepatic metastases were immunohistochemically stained for p107 , cyclin A , cyclin E , CDK2 and Ki67 . Results were measured using labelling indices ( LIs). p107 LIs surpassed the highest value in normal tissues in six of nine hyperplastic polyps , 54 of 60 adenomas , 144 of 198 primary cancers , 13 of 21 nodal foci and three of 10 hepatic foci. p107 LIs also apparently rose from normal through hyperplasia and adenoma to early carcinoma . However , they declined in liver-metastatic foci , and in primary cancers showing large size , mucinous type , venous invasion , lymphatic invasion , poorly differentiated type , deep invasion , lymph-nodal metastasis , hepatic metastasis or advanced stage . Low p107 LIs were also linked to a poor survival , particularly in stage-III patients . As the p107 LI gradually rose , the CDK2 ( in primary cancers only ) , cyclin A , cyclin E and Ki67 LIs were elevated concurrently-in both adenomas and primary cancers . Thus , in colorectal tumours , p107 expression rises abnormally and gradually during carcinogenesis and then falls during invasion , and thereby probably perturbs the cell-cycle control and promotes carcinogenesis and invasion . Clinically , reduced p107 may indicate a poorer prognosis .
|
[
1,
0,
0,
0,
0,
0,
0,
0,
0,
0
] |
12204665
|
Objective . The present study was performed to investigate the effect of N-desulfated heparin on basic fibroblast growth factor ( bFGF ) expression , tumor angiogenesis and metastasis of gastric carcinoma . Methods . Human gastric cancer SGC-7901 tissues were orthotopically implanted into the stomach of NOD SCID mice . Twenty mice were randomly divided into two groups which received either intravenous injection of 0.9% NaCl solution ( normal saline group ) or 10 mg/kg N-desulfated heparin ( N-desulfated heparin group ) twice weekly for three weeks . In vitro , human gastric carcinoma SGC-7901 cells were treated with N-desulfated heparin in different concentration ( 0.1 mg/mL , 1 mg/mL , N-desulfated heparin group ) , and treated with medium ( control group ) . Results . In vivo , the tumor metastasis rates were 9/10 in normal saline group and 2/10 in N-desulfated heparin group ( P < 0.05 ) . The intratumoral microvessel density was higher in normal saline group than in N-desulfated heparin group ( P < 0.05). bFGF expression in gastric tissue was inhibited by N-desulfated heparin ( P < 0.05 ) . There was no bleeding in N-desulfated heparin group . In vitro , N-desulfated heparin inhibited significantly bFGF protein and mRNA expression of gastric carcinoma cells ( P < 0.05 ) . Conclusions . N-desulfated heparin can inhibit the metastasis of gastric cancer through inhibiting tumor bFGF expression and tumor angiogenesis with no obvious anticoagulant activity .
|
[
1,
0,
0,
0,
0,
0,
1,
0,
0,
0
] |
22888341
|
1-Vinylcycloalkenes undergo highly regio- and enantioselective ( >98% ee ) 1,4-hydrovinylation ( HV ) when treated with ethylene ( 1 atm ) at room temperature in the presence of [ (S,S)-2,4-bis-diphenylphosphinopentane ( BDPP)]CoCl(2 ) ( 0.05 equiv ) and methylaluminoxane . The minor 1,2-HV products , seen only in 1-vinylcyclohexene ( and 1-vinylcycloheptene ( 2% ) , are formed as racemic mixtures . The corresponding Ni(II)-catalyzed HV reactions of these substrates give mostly the 1,2-adducts . Racemic 4-tert-butyl-1-vinylcyclohexene , when treated with Co[(S,S)-(BDPP)]Cl(2) and ethylene , undergoes a rare enantiodivergent reaction giving two diastereomers each in >98% ee .
|
[
0,
0,
0,
0,
0,
0,
0,
0,
0,
0
] |
22452442
|
The aberrant activation of sonic hedgehog ( SHH ) pathway contributes to initiation and progression of various malignancies . However , the roles and underlying mechanisms of SHH signaling pathway in invasion and metastasis of liver cancer have not been well understood . In this study , we found that SHH signaling was activated and correlated with invasion and metastasis in hepatocellular carcinoma ( HCC ) . Enhanced SHH signaling by recombinant human SHH N-terminal peptide ( rSHH-N ) promoted hepatoma cell adhesion , migration and invasion , whereas blockade of SHH signaling with SHH neutralizing antibody or cyclopamine suppressed hepatoma cell adhesion , migration and invasion . Furthermore , matrix metalloproteinase ( MMP)-2 and MMP-9 expressions and activities were upregulated and downregulated by rSHH-N and SHH signaling inhibitor , respectively . The rSHH-N-mediated hepatoma cell migration and invasion was blocked by MMP-specific inhibitors or neutralizing antibodies to MMP-2 and MMP-9 . In addition , phosphorylations of AKT and focal adhesion kinase ( FAK ) were increased and decreased by rSHH-N and SHH signaling inhibitor , respectively . Further investigations showed that activation of AKT and FAK were required for rSHH-N-mediated upregulation of MMP-2 and MMP-9 , cell migration and invasion . Finally , we found that SHH protein expression was positively correlated with phosphorylatd FAK Tyr397 , phosphorylatd AKT Ser473 , MMP-2 and MMP-9 protein expressions in HCC samples . Taken together , our findings suggest that SHH pathway induces cell migration and invasion through FAK/AKT signaling-mediated MMP-2 and MMP-9 production and activation in liver cancer .
|
[
1,
0,
0,
0,
0,
0,
0,
0,
0,
0
] |
22948179
|
The NOTCH signaling pathway plays important role in the development of multicellular organisms , as it regulates cell proliferation , survival , and differentiation . In adults , it is essential for the T- or B-lymphocyte lineage commitment . NOTCH1 and FBXW7 mutations both lead the activation of the NOTCH1 pathway and are found in the majority of T-ALL patients . In this study , the mutation analysis of NOTCH1 and FBXW7 genes was performed in 87 pediatric T-ALLs who were treated on the ALL-BFM protocols . In 19 patients ( 22% ) , activating NOTCH1 mutations were observed either in the heterodimerization domain or in the PEST domain and 7 cases ( 10% ) demonstrated FBXW7 mutations ( 2 cases had both NOTCH1 and FBXW7 mutations ) . We also analyzed the relationship of the mutation data between the clinical and biological data of the patients . NOTCH1 and FBXW7 , NOTCH1 alone were found correlated with lower initial leucocyte counts which was independent from the sex and T- cell immunophenotype . However , NOTCH1 and FBXW7 mutations were not predictive of outcome in the overall cohort of pediatric T-ALLs .
|
[
0,
0,
0,
0,
0,
1,
0,
0,
0,
0
] |
20683149
|
Various endocrine disrupting chemicals ( EDCs ) are exogenous compounds found in the environment and have the potential to interfere with the endocrine system and hormonal regulation . Among EDCs , bisphenolA ( BPA ) and 1,1,1-trichloro-2,2-bis(4-methoxyphenol)-ethane [ methoxychlor ( MXC) ] have estrogenic activity resulting in a variety of dysfunctions in the E2-mediated response by binding to estrogen receptors ( ERs ) , causing human health problems such as abnormal reproduction and carcinogenesis . In this study , we investigated the effects of BPA and MXC on cell proliferation facilitated by ER signaling in human breast cancer cells . MCF-7 cells are known to be ERα-positive and to be a highly E2-responsive cancer cell line ; these cells are , therefore , a useful invitro model for detecting estrogenic activity in response to EDCs . We evaluated cancer cell proliferation following BPA and MXC treatment using an MTT assay . We analyzed alterations in the expression of genes associated with the cell cycle in MCF-7 cells by semi-quantitative reverse-transcription PCR following treatment with BPA or MXC compared to EtOH . To determine whether BPA and MXC stimulate cancer cell growth though ER signaling , we co-treated the cells with agonists ( propyl pyrazoletriol , PPT ; and diarylpropionitrile , DPN ) or an antagonist ( ICI 182,780 ) of ER signaling and reduced ERα gene expression via siRNA in MCF-7 cells before treatment with EDCs . These studies confirmed the carcinogenicity of EDCs invitro . As a result , BPA and MXC induced the cancer cell proliferation by the upregulation of genes that promote the cell cycle and the downregulation of anti-proliferative genes , especially ones affecting the G1/S transition via ERα signaling . These collective results confirm the carcinogenicity of these EDCs invitro . Further studies are required to determine whether EDCs promote carcinogenesis invivo .
|
[
0,
0,
0,
0,
0,
0,
0,
0,
1,
0
] |
22307313
|
BACKGROUND The 235delC mutation of GJB2 gene is considered as a risk factor for the non-syndromic hearing loss ( NSHL ) , and a significant difference in the frequency and distribution of the 235delC mutation has been described world widely . METHODS A systematic review was performed by means of a meta-analysis to evaluate the influence of the 235delC mutation on the risk of NSHL . A literature search in electronic databases using keywords " 235delC " , " GJB2 " associated with " carrier frequency " was conducted to include all papers from January 1999 to June 2011 . A total of 36 papers were included and there contained 13217 cases and 6521 controls derived from Oceania , American , Europe and Asian . RESULTS A remarkable heterogeneity between these studies was observed . The combined results of meta-analysis showed that the 235delC mutant increased the risk of NSHL ( OR = 7.9 , 95%CI 4.77 13.11 , P <0.00001 ) . Meanwhile , heterogeneity of genetic effect was also observed due to the ethnic specificity and regional disparity . Therefore , the stratified meta-analysis was subsequently conducted and the results indicated that the 235delC mutation was significantly correlated with the risk of NHSL in the East Asian and South-east Asian populations ( OR = 12.05 , 95%CI 8.33 P <0.00001 ) , but not significantly in the Oceania and European populations ( OR = 10.36 , 95%CI : 4.68 Z = 1.68 , P >0.05 ) . CONCLUSIONS The 235delC mutation of GJB2 gene increased the risk of NHSL in the East Asian and South-east Asian populations , but non-significantly associated with the NSHL susceptibility in Oceania and European populations , suggesting a significant ethnic specificity of this NSHL-associated mutation .
|
[
0,
0,
0,
0,
0,
0,
0,
0,
0,
0
] |
22747691
|
While human embryonic stem cells ( hESCs ) and human embryonal carcinoma cells ( hECCs ) have been studied extensively at the levels of the genome , transcriptome , proteome and epigenome our knowledge of their corresponding metabolomes is limited . Here , we present the metabolic signatures of hESCs and hESCs obtained by untargeted gas chromatography coupled to mass spectrometry ( GC-MS ) . Whilst some metabolites are common to both cell types , representing the self-renewal and house-keeping signatures , others were either higher ( e.g. , octadecenoic acid , glycerol-3-phosphate , 4-hydroxyproline ) or lower ( e.g. , glutamic acid , mannitol , malic acid , GABA ) in hESCs ( H9 ) compared to hECCs ( NTERA2 ) , these represent cell type specific signatures . Further , our combined results of GC-MS and microarray based gene expression profiling of undifferentiated and OCT4-depleted hESCs are consistent with the Warburg effect which is increased glycolysis in embryonic cells and tumor cells in the presence of O(2) while oxidative phosphorylation ( OXPHOS ) is impaired or even shut down . RNAi-based OCT4 knock down mediated differentiation resulted in the activation of the poised OXPHOS machinery by expressing missing key proteins such as NDUFC1 , UQCRB and COX , increase in TCA cycle activity and decreased lactate metabolism . These results shed light on the metabolite layer of pluripotent stem cells and could potentially establish novel metabolic markers of self renewal and pluripotency .
|
[
0,
0,
1,
0,
0,
0,
0,
0,
0,
0
] |
22768158
|
Tumor development requires angiogenesis and anti-angiogenic therapies have been introduced in the treatment of cancer . In this context , heparan sulfate proteoglycans ( HSPGs ) emerge as interesting targets , owing to their function as co-receptors of major , pro-angiogenic factors . Accordingly , previous studies have suggested anti-tumor effects of heparin , i.e. over-sulfated HS , and various heparin mimetics ; however , a significant drawback is their unspecific mechanism of action and potentially serious side-effects related to their anticoagulant properties . Here , we have explored the use of human ScFv anti-HS antibodies ( αHS ) as a more rational approach to target HSPG function in endothelial cells ( ECs). αHS were initially selected for their recognition of HS epitopes localized preferentially to the vasculature of patient glioblastoma tumors , i.e. highly angiogenic brain tumors . Unexpectedly , we found that these αHS exhibited potent pro-angiogenic effects in primary human ECs. αHS were shown to stimulate EC differentiation , which was associated with increased EC tube formation and proliferation . Moreover , αHS supported EC survival under hypoxia and starvation , i.e. conditions typical of the tumor microenvironment . Importantly , αHS-mediated proliferation was efficiently counter-acted by heparin and was absent in HSPG-deficient mutant cells , confirming HS-specific effects . On a mechanistic level , binding of αHS to HSPGs of ECs as well as glioblastoma cells was found to trigger p38 MAPK-dependent signaling resulting in increased proliferation . We conclude that several αHS that recognize HS epitopes abundant in the tumor vasculature may elicit a pro-angiogenic response , which has implications for the development of antibody-based targeting of HSPGs in cancer .
|
[
0,
0,
0,
0,
0,
0,
1,
0,
1,
0
] |
23152853
|
Radiation combined with chemotherapy ( neo-CRT ) is increasingly the standard of care for the treatment of esophageal cancer , either as neoadjuvant therapy in multimodal protocols or as primary therapy . Unfortunately , of patients demonstrate little or no response to neo-CRT . Accordingly , understanding the molecular mechanisms of resistance to therapy may underpin significant advances through the identification of nonresponders either before or early in treatment . We previously identified the RNPC1 gene , which is important in stabilizing p21 , as being upregulated in the tumors of esophageal cancer patients who had a poor response to neo-CRT . We hypothesize that RNPC1 contributes to resistance to radiation therapy through a p21-mediated cell cycle accumulation/arrest mechanism . Analysis revealed that p53 and RNPC1 expression were highest in the JH-EsoAd1 cell line and lowest in OE19 cells . This was associated with accumulation of cells in G₀/G₁. p21 expression , which was highest in OE19 cells and lowest in OE33 cells , was associated with relative intrinsic sensitivity to radiation . OE33 cells were transfected with a plasmid ( pCMV6-AC-GFP ) encoding a C-terminal GFP-tagged RNPC1 , and overexpression was confirmed by qPCR and fluorescence microscopy . Overexpression of RNPC1-GFP resulted in significantly increased levels of the p21 transcript and protein through a direct physical interaction between the RNPC1 protein and the p21 transcript . Furthermore , RNPC1 overexpression led to significant G₀/G₁ cell cycle accumulation and significantly enhanced cellular resistance to radiation . We conclude that RNPC1 contributes to tumor resistance to radiotherapy , which likely occurs through a p21-mediated G₀/G₁ accumulation mechanism . Therefore , RNPC1 may represent a potential therapeutic target for enhancing tumor sensitivity to radiation .
|
[
0,
0,
0,
0,
0,
0,
0,
0,
0,
0
] |
22214381
|
Targeting receptor tyrosine kinase ( RTK ) degradation may be an interesting approach to reduce RTK cell signaling in cancer cells . Here we show that increasing E3 ubiquitin ligase casitas B-lineage lymphoma ( c-Cbl ) expression using lentiviral infection decreased osteosarcoma cell replication and survival and reduced cell migration and invasion in murine and human osteosarcoma cells . Conversely , c-Cbl inhibition using short hairpin RNA ( shRNA ) increased osteosarcoma cell growth and survival , as well as invasion and migration , indicating that c-Cbl plays a critical role as a bone tumor suppressor . Importantly , the anticancer effect of increasing c-Cbl expression in osteosarcoma cells was related mainly to the downregulation of epidermal growth factor receptor ( EGFR ) and platelet-derived growth factor receptor alpha ( PDGFRα ) . In a murine bone tumor model , increasing c-Cbl expression also reduced RTK expression , resulting in decreased tumor cell proliferation and survival and reduced tumor growth . Interestingly , increasing c-Cbl also markedly reduced lung metastasis in mice . Tissue microarray analysis revealed that low c-Cbl protein expression is associated with elevated EGFR and PDGFRα protein levels in human osteosarcoma with poor outcome . This study shows that increasing c-Cbl expression reduces osteosarcoma cell growth , survival , and metastasis in part through downregulation of RTKs , which supports the potential therapeutic interest of targeting c-Cbl in malignant bone diseases involving increased RTK .
|
[
1,
0,
0,
0,
0,
0,
0,
0,
1,
0
] |
22623369
|
Urokinase plasminogen activator receptor ( uPAR ) activates alpha5beta1 integrin and ERK signaling , inducing in vivo proliferation of HEp3 human carcinoma . Here we demonstrate that EGFR mediates the uPAR/integrin/fibronectin ( FN ) induced growth pathway . Its activation is ligand-independent and does not require high EGFR , but does require high uPAR expression . Only when uPAR level is constitutively elevated does EGFR become alpha5beta1-associated and activated . Domain 1 of uPAR is crucial for EGFR activation , and FAK links integrin and EGFR signaling . Inhibition of EGFR kinase blocks uPAR induced signal to ERK , implicating EGFR as an important effector of the pathway . Disruption of uPAR or EGFR signaling reduces HEp3 proliferation in vivo . These findings unveil a mechanism whereby uPAR subverts ligand-regulated EGFR signaling , providing cancer cells with proliferative advantage .
|
[
0,
0,
0,
0,
0,
0,
0,
0,
1,
0
] |
12124174
|
It is well established that aberrant production of inflammatory mediators has been associated with most the toxic manifestations and the genesis of different chronic diseases including cancer . The basic aim of the present study is to investigate the effects of soy isoflavones ( SIF ) on 12-O-tetradecanoylphorbol-13-acetate ( TPA)-induced cutaneous inflammatory responses and to explore the underlying molecular mechanisms . We have studied the protective effects of SIF against TPA induced oxidative stress , pro-inflammatory cytokines level , activation of NF-κB , expression of COX-2 and ki-67 in mouse skin . Animals were divided into five groups I-V ( n=6 ) . Groups II , III and IV received topical application of TPA at the dose of 10 nmol/0.2 ml of acetone/animal/day , for 2 days . Animals of the groups III and IV were pre-treated with SIF 1.0 μg ( D1 ) and 2.0 μg ( D2 ) topically 30 min prior to each TPA administration , while groups I and V were given acetone ( 0.2 ml ) and SIF ( D2 ) , respectively . We have found that SIF pretreatment significantly inhibited TPA induced oxidative stress , proinflammatory cytokines production and activation of NF-κB . SIF also inhibited the expression of COX-2 and ki-67 . Histological findings further supported the protective effects of SIF against TPA-induced cutaneous damage . Thus , our results suggest that inhibitory effect of SIF on TPA-induced cutaneous inflammation includes inhibition of proinflammatory cytokines , attenuation of oxidative stress , activation of NF-κB and expression of COX-2 .
|
[
0,
0,
0,
0,
0,
0,
0,
0,
0,
1
] |
22981962
|
INTRODUCTION The progressive growth of malignancies is accompanied by a decline in the immune response through mechanisms which are poorly understood . Apoptosis and induction of inflammation by tumor released cytokines as tumor escape mechanisms have been proposed to play an important role in colorectal carcinogenesis . METHODS Expression of Tumor necrosis factor-alpha ( TNF-α ) was analyzed in colorectal cancer specimen and the cancer cell line HT-29 by immunohistochemistry and RT-PCR . TNF-α expression on protein and mRNA level were correlated with clinical characteristics and impact on survival . TNFR-1 was co-labelled with TNF-α and CD8+ cytotoxic T cells in immunofluorescence double staining experiments . RESULTS 94% ( n=98/104 ) of the patients with CRC expressed TNF-α . High TNF-α expression was significantly associated with positive lymph node stage and recurrence of the tumor . Multivariate analysis revealed high TNF-α expression as an independent prognostic factor . Immunohistochemistry was correlated with RT-PCR results ( τ=0.794 ) . Immunofluorescence double staining experiments revealed increased TNFR-1 expression by CD8+ cells . CONCLUSIONS TNF-α expression by tumor cells may be an efficient immunological escape mechanism by inflammation-enhanced metastases and probably by induction of apoptosis in tumor-infiltrating CD8+ immune cells resulting in a down regulation of the tumoral immune response . Our data support the role of tumor-derived TNF-α expression as an important promoter of tumoral immune escape mechanisms and malignant progression , and suggest that analysis on either protein ( immunohistochemistry ) or RNA level ( RT-PCR ) can be used effectively in this respect . Targeting TNF-α may be a promising option , especially in cases with high TNF-α expression and positive lymph node metastases .
|
[
1,
0,
0,
0,
0,
0,
0,
0,
0,
1
] |
20978325
|
Endocrine gland-derived vascular endothelial growth factor ( EG-VEGF ) has recently been identified as one of the vascular endothelial growth factors , and it is considered that the overexpression of EG-VEGF in colon cancer is related to hepatic metastasis . In this study , we report our recent novel findings of the involvement of EG-VEGF in cell invasion of colon cancer cells . Colon cancer cell lines ( DLD-1 and HCT116 ) with high expression of prokineticin receptor ( PK-R ) 1 and 2 were stimulated with the EG-VEGF protein . Furthermore , Matrigel cell invasion assay was performed to examine the changes in cancer cell invasion . In addition , we investigated the mRNA expression of matrix metalloproteinase ( MMP)-2 , -7 and -9 in cancer cells . Finally , the EG-VEGF receptor on the colon cancer cell membrane was blocked by anti-PK-R1 and -PK-R2 antibodies to study whether cell invasion ability would be altered . In colon cancer cell lines where the expression of PK-R1 and 2 was confirmed , stimulation with EG-VEGF increased cell invasion a maximum of times . Furthermore , an increase in the mRNA and protein expression of MMP-2 , -7 and -9 was observed . We also observed that the cell invasion rate decreased only after exposure to the anti-PK-R2 antibody . The study showed that the EG-VEGF protein may act on MMP-2 , -7 and -9 via PK-R2 to strengthen cell invasion ability in colon cancer cell lines .
|
[
0,
0,
0,
0,
0,
0,
0,
0,
0,
0
] |
23135359
|
Liver resection is now widely accepted as a potentially curative treatment for colorectal liver metastasis . However , the efficacy of surgical resection for gastric cancer liver metastasis(GLM)remains unclear . Based on our 18-year experience with 64 patients who underwent curative hepatectomy for GLM , we discuss the indication and efficacy of surgical resection for GLM . From January 1993 to January 2011 , 73 patients underwent hepatectomy for GLM in the Department of Gastroenterological Surgery , Cancer Institute Ariake Hospital(Japanese Foundation for Cancer Research ) , Japan . The actuarial1 - , 3- , and 5-year overall survival rates and 1- , 3- , and 5-year recurrence-free survival rates of those 64 patients who achieved curative resections were 84 , 50 , and 37% , and 42 , 27 , and 27% , respectively . By multivariate analysis , serosal invasion of the primary gastric cancer and larger hepatic tumor(>5 cm in diameter)were found to be independent indicators of poor prognosis . Based on the multivariate analysis results , all patients were divided into three groups no poor prognostic factor(n=38) , one poor prognostic factor(n=24) , and two poor prognostic factors(n=2) . The actuarial overall survival rates of each group were 63 , 36 , and 0% at 3 years , and 53 , 15 , and 0% at 5 years . GLM patients having hepatic tumors with the maximum diameter of <5 cm , and without serosalinvasion of the primary gastric cancer , are the best candidates for hepatectomy .
|
[
1,
0,
0,
0,
0,
0,
0,
0,
0,
0
] |
23235164
|
Many tumors contain heterogeneous populations of cells , only some of which exhibit increased tumorigenicity and resistance to anticancer therapies . Evidence suggests that these aggressive cancer cells , often termed " cancer stem cells " or " cancer stem-like cells " ( CSCs ) , rely upon developmental signaling pathways that are important for survival and expansion of normal stem cells . Here we report that , in analogy to embryonic mammary epithelial biology , estrogen signaling expands the pool of functional breast CSCs through a paracrine FGF/FGFR/Tbx3 signaling pathway . Estrogen or FGF9 pretreatment induced CSC properties of breast cancer cell lines and freshly isolated breast cancer cells , whereas cotreatment of cells with tamoxifen or a small molecule inhibitor of FGFR signaling was sufficient to prevent the estrogen-induced expansion of CSCs . Furthermore , reduction of FGFR or Tbx3 gene expression was able to abrogate tumorsphere formation , whereas ectopic Tbx3 expression increased tumor seeding potential by 100-fold . These findings demonstrate that breast CSCs are stimulated by estrogen through a signaling pathway that similarly controls normal mammary epithelial stem cell biology .
|
[
0,
0,
0,
0,
0,
0,
0,
0,
1,
0
] |
21098263
|
Triggering tumor necrosis factor receptor-1 ( TNFR1 ) induces apoptosis in various cell lines . In contrast , stimulation of TNFR1 in L929sA leads to necrosis . Inhibition of HSP90 , a chaperone for many kinases , by geldanamycin or radicicol shifted the response of L929sA cells to TNF from necrosis to apoptosis . This shift was blocked by CrmA but not by BCL-2 overexpression , suggesting that it occurred through activation of procaspase-8 . Geldanamycin pretreatment led to a proteasome-dependent decrease in the levels of several TNFR1-interacting proteins including the kinases receptor-interacting protein , inhibitor of kappa B kinase-alpha , inhibitor of kappa B kinase-beta , and to a lesser extent the adaptors NF-kappaB essential modulator and tumor necrosis factor receptor-associated factor 2 . As a consequence , NF-kappa B , p38MAPK , and JNK activation were abolished . No significant decrease in the levels of mitogen-activated protein kinases , adaptor proteins TNFR-associated death domain and Fas-associated death domain , or caspase-3 , -8 , and -9 could be detected . These results suggest that HSP90 client proteins play a crucial role in necrotic signaling . We conclude that inhibition of HSP90 may alter the composition of the TNFR1 complex , favoring the caspase-8-dependent apoptotic pathway . In the absence of geldanamycin , certain HSP90 client proteins may be preferentially recruited to the TNFR1 complex , promoting necrosis . Thus , the availability of proteins such as receptor-interacting protein , Fas-associated death domain , and caspase-8 can determine whether TNFR1 activation will lead to apoptosis or to necrosis .
|
[
0,
0,
0,
0,
0,
0,
0,
1,
0,
0
] |
12441346
|
We showed in a previous study that soluble low-molecular-mass tumor-associated antigens ( sTAA ) promote the anti-tumor effect of the anticancer drug cyclophosphamide ( CPA ) on rat mammary carcinogenesis . In this report , we analyzed the possible mechanism underlying this phenomenon . Studies were performed on the bone marrow and thymus from the following groups of rats : i ) control rats , ii ) rats treated with sTAA , iii ) rats treated with CPA , iv ) rats treated with CPA and sTAA . The cellular content of the bone marrow and thymus ( CD4+ and CD8+ lymphocytes ) was analyzed morphometrically and immunohistochemically . In the bone marrow , CPA caused significant substitution of cellular components with fatty tissue whereas sTAA repaired this process . We found that CPA affects mainly the process of myelogenesis whereas sTAA protect the production of lymphocytes . In the thymus , CPA alone or in combination with sTAA repaired the inhibition effect of DMBA on synthesis of CD4+ and CD8+ thymocytes. sTAA further increased the amount of CD8+ T lymphocytes in the medulla of the thymus . Data in the literature as well as the findings presented here demonstrate that the tested treatment , including vaccination with sTAA , actively promotes the generation of the host's antitumor immune response .
|
[
0,
1,
0,
0,
0,
0,
0,
0,
0,
0
] |
12239604
|
Epidemiological data and animal models have provided evidence that nonsteroidal antiinflammatory drugs ( NSAIDs ) have an anticancer effect . However , the molecular mechanisms underlying these antineoplastic effects are not well understood . We described previously that expression levels of the chemokine receptor , CCR5 , and the beta2-integrin , Mac-1 , were down-regulated on primary monocytes after incubation in supernatants from human carcinoma cell lines , and that this down-regulation resulted in impaired monocyte function with respect to migration and adhesion . We now demonstrate that these impairments are also present in vivo . Monocytes from cancer patients displayed significantly reduced CCR5 levels and migration capacities in comparison to cells from healthy donors . Because migration is necessary for the antitumor activity of monocytes/macrophages , these deficits may contribute to the suppressed immune system seen in cancer patients . In a clinical study , we analyzed the effect of a selective COX-2 inhibitor , Rofecoxib , on the migration of monocytes derived from cancer patients . The results revealed significant improvement in migration equal to those levels seen in healthy donors . We conclude that in patients with cancer , the intake of Rofecoxib for 3 wk leads to significant restoration of monocyte function . These data may , at least in part , help explain the anticancer effects of NSAIDs .
|
[
0,
1,
0,
0,
0,
0,
0,
0,
0,
0
] |
12490541
|
Interactions of CD70 , a tumor necrosis factor-related cell surface ligand and its receptor , CD27 , are thought to play an important role for T- , B- , and natural killer-cell activation . However , ligation of CD27 can also induce apoptosis . Human glioblastoma is paradigmatic for cancer-associated immunosuppression . We identified CD70 as a radioinducible gene in U87 MG glioma cells . A screening of a panel of human glioma cell lines revealed that 11 of 12 cell lines expressed CD70 mRNA and protein . Two human neuroblastoma cell lines did not express CD70 . CD70 mRNA expression was enhanced by irradiation in 8 of 12 glioma cell lines in a p53-independent manner . No alteration in CD70 expression was observed after glioma cell exposure to cytotoxic drugs such as lomustine . CD70 protein was also detected by immunocytochemistry in 5 of 12 glioblastomas and 3 of 4 anaplastic astrocytomas in vivo . CD27 expression was not detected in any glioma cell line , and there was no evidence for autocrine or backward signaling of the CD70 system in human glioma cells . Unexpectedly , CD70 expressed on glioma cells did not increase the immunogenicity of glioma cells in vitro . In contrast , CD70-positive glioma cells induced apoptosis in peripheral blood mononuclear cells ( PBMCs ) in a CD70-dependent manner . Neutralization of CD70 expressed on glioma cells prevented apoptosis and enhanced the release of tumor necrosis factor-alpha in cocultures of glioma cells and PBMCs . The effects of CD70-expressing glioma cells on PBMCs were mimicked by agonistic CD27 antibodies . Conversely , the shedding of CD27 by PBMCs was identified as a possible escape mechanism from glioma cell-induced CD70-dependent apoptosis . Thus , induction of B-cell and T-cell apoptosis via interactions of CD70 expressed on glioma cells and CD27 expressed on B and T cells may be a novel way for the immune escape of malignant gliomas .
|
[
0,
1,
0,
0,
0,
0,
0,
1,
0,
0
] |
11980654
|
ABSTRACT : INTRODUCTION : Retinoic acid signaling plays key roles in embryonic development and in maintaining the differentiated status of adult tissues . Recently , the nuclear retinoic acid receptor ( RAR ) isotypes α , β and γ were found to play specific functions in the expansion and differentiation of the stem compartments of various tissues . For instance , RARγ appears to be involved in stem cell compartment expansion , while RARα and RARβ are implicated in the subsequent cell differentiation . We found that over-expressing c-Myc in normal mouse mammary epithelium and in a c-Myc-driven transgenic model of mammary cancer , disrupts the balance between RARγ and RARα/β in favor of RARγ . METHODS : The effects of c-Myc on RAR isotype expression were evaluated in normal mouse mammary epithelium , mammary tumor cells obtained from the MMTV-Myc transgenic mouse model as well as human normal immortalized breast epithelial and breast cancer cell lines . The in vivo effect of the RARα-selective agonist 4-[(5,6,7,8-tetrahydro-5,5,8,8-tetramethyl-2-naphthyl)carboxamido]benzoic acid ( Am580 ) was examined in the MMTV-Myc mouse model of mammary tumorigenesis . RESULTS : Modulation of the RARα/β to RARγ expression in mammary glands of normal mice , oncomice , and human mammary cell lines through the alteration of RAR-target gene expression affected cell proliferation , survival and tumor growth . Treatment of MMTV-Myc mice with the RARα-selective agonist Am580 led to significant inhibition of mammary tumor growth ( P<0.001 ) , lung metastasis ( P<0.01 ) and extended tumor latency in 63% of mice . Immunocytochemical analysis showed that in these mice , RARα responsive genes such as Cyp26A1 , E-cadherin , cellular retinol-binding protein 1 ( CRBP1 ) and p27 , were up-regulated . In contrast , the mammary gland tumors of mice that responded poorly to Am580 treatment ( 37% ) expressed significantly higher levels of RARγ . In vitro experiments indicated that the rise in RARγ was functionally linked to promotion of tumor growth and inhibition of differentiation . Thus , activation of the RARα pathway is linked to tumor growth inhibition , differentiation and cell death . CONCLUSIONS : The functional consequence of the interplay between c-Myc oncogene expression and the RARγ to RARα/β balance suggests that prevalence of RARγ over-RARα/β expression levels in breast cancer accompanied by c-Myc amplification or over-expression in breast cancer should be predictive of response to treatment with RARα-isotype-specific agonists and warrant monitoring during clinical trials.See related editorial by Garattini et al http://breast-cancer-research.com/content/14/5/111 .
|
[
0,
0,
0,
0,
0,
0,
0,
0,
0,
0
] |
22920668
|
AIM We studied expression of molecules of the vascular endothelial growth factor ( VEGF ) pathway and its relation to vascularization , cell proliferation and patient outcome in recurring non-anaplastic meningioma . We studied 29 tumor specimens of 8 patients with recurring meningiomas and of 8 age- and gender-matched control patients with non-recurring meningiomas ( including meningothelial , transitional , fibroblastic and atypical subtypes ) using immunohistochemistry and in-situ hybridization . RESULTS VEGF protein , VEGF-mRNA , VEGF receptor ( VEGFR)-1 mRNA , VEGFR-2 mRNA and hypoxia-inducible factor ( HIF)-1-α protein were expressed in 27/29 ( 93% ) , 20/27 ( 74% ) , 9/27 ( 33.3% ) , 12/27 ( 44.4% ) and 5/29 ( 17.2% ) specimens , respectively . VEGFR- 2 mRNA expression was found in 6/8 tumors extracted at first operation in patients with recurring tumors and in none of the control cases ( p = 0.007 ) . Microvessel density ( MVD ) and Ki-67 index values were generally higher in meningiomas with expression of angiogenic factors . The association of high Ki-67 index values with VEGF-mRNA expression was significant ( p = 0.04 ) . Time to recurrence was shorter in patients with high MVD than in patients with low MVD ( p = 0.027 ) . CONCLUSIONS High MVD correlates with unfavorable prognosis in our series of recurring meningioma . VEGF and its receptors are frequently expressed in meningiomas and seem important for tumor growth and recurrence . Thus , anti-VEGF therapy in aggressive meningioma seems rational from a pathobiological point of view .
|
[
0,
0,
0,
0,
0,
0,
1,
0,
0,
0
] |
22541785
|
The concept of targeting new blood vessel formation , or angiogenesis , in tumors is an important advancement in cancer therapy , resulting , in part , from the development of such biologic agents as bevacizumab , a monoclonal antibody directed against vascular endothelial growth factor ( VEGF)-A . The rationale for antiangiogenic therapy is based on the hypothesis that if tumors are limited in their capacity to obtain a new blood supply , so too is their capacity for growth and metastasis . Additional evidence suggests that pruning and/or " normalization " of irregular tumor vasculature and reduction of hypoxia may facilitate greater access of cytotoxic chemotherapy ( CT ) to the tumor . Indeed , for metastatic colorectal cancer , bevacizumab in combination with established CT regimens has efficacy superior to that of CT alone . Despite longer progression-free and overall survival times than with CT alone , patients still progress , possibly because of alternative angiogenic " escape " pathways that emerge independent of VEGF-A , or are driven by hypoxic stress on the tumor . Other VEGF family members may contribute to resistance , and many factors that contribute to the regulation of tumor angiogenesis function as part of a complex network , existing in different concentrations and spatiotemporal gradients and producing a wide range of biologic responses . Integrating these concepts into the design and evaluation of new antiangiogenic therapies may help overcome resistance mechanisms and allow for greater efficacy over longer treatment periods .
|
[
0,
0,
0,
0,
0,
0,
0,
0,
0,
0
] |
22773560
|
The submandibular gland-derived tumor cell line SCA-9 is considered a useful tool to study the signaling pathways involved in proliferation , and their regulation , triggered by different stimuli . It is proposed that the non neuronal cholinergic system : acethylcholine , the enzymes that synthesize and degrade it , and the nicotinic and muscarinic receptors , play a key role in tumorigenesis . Here , we investigate the role of muscarinic receptors in SCA-9 cell proliferation , and the modulation of cholinergic signaling pathways exerted by the nuclear transcription factor κB ( NF-κB ) . The activation of cholinergic receptors by carbachol ( 10⁻⁹M ) increased cell proliferation ( P<0.001 ) . This was prevented by preincubating cells with the muscarinic antagonist atropine but not by mecamylamine , a nicotinic receptor blocker . Phospholipase C ( PLC)/nitric oxide synthase ( NOS)/arginase pathway is involved in this effect , since carbachol stimulated nitric oxide production , increased NOS2 and NOS3 expressions , urea production , and arginase II expression ( P<0.001 ) . Also , phospholipase A₂ ( PLA₂)/cyclooxygenase ( COX ) pathway is up-regulated in carbachol-induced SCA-9 cell proliferation , because prostaglandin E₂ liberation ( P<0.001 ) is increased and COX-1 expression is turned up ( P<0.001 ) . Interactions between PLC/NOS/arginases and PLA₂/COX pathways via its metabolites were detected . SCA-9 cells exhibit a constitutive activation of NF-κB , which regulates carbachol-induced NOS2 and 3 , arginase II and COX-1 expressions . In addition , protein kinase C is involved in the up-regulation of NOS2 and arginase II enzymes induced by carbachol via NF-κB . In conclusion , the activation of cholinergic receptors in SCA-9 tumor cells promotes proliferation via muscarinic effector enzymes , and reveals the participation of NF-κB at this step of tumorigenesis .
|
[
0,
0,
0,
0,
0,
0,
0,
0,
1,
0
] |
22449386
|
Bilateral spontaneous pneumothorax is a rare occurrence in patients with both primary and metastatic lung cancer . Pneumothorax occurring as a complication of vascular endothelial growth factor receptor ( VEGFR ) inhibitor therapy has not been previously described in the medical literature . Sunitinib malate is a VEGFR inhibitor approved for the treatment of advanced renal cell carcinoma . We present a patient with metastatic renal cell carcinoma manifested as bilateral pulmonary nodules who developed a bilateral spontaneous pneumothorax 3 weeks after initiation of sunitinib therapy . We believe that sunitinib therapy resulted in necrosis of multiple pleural-based pulmonary nodules with central cavernization and ultimately rupture with bronchopleural fistula formation . Based on this experience , we advise that practitioners exercise caution when prescribing anti-VEGFR therapy in patients with pleural-based pulmonary metastases and recognize that the efficacy and toxicity of these agents may be closely linked .
|
[
0,
0,
0,
0,
0,
0,
0,
1,
0,
0
] |
20204363
|
γ-Tocotrienol and sesamin are phytochemicals that display potent anticancer activity . Since sesamin inhibits the metabolic degradation of tocotrienols , studies were conducted to determine if combined treatment with sesamin potentiates the antiproliferative effects of γ-tocotrienol on neoplastic mouse ( +SA ) and human ( MCF-7 and MDA-MB-231 ) mammary cancer cells . Results showed that treatment with γ-tocotrienol or sesamin alone induced a significant dose-responsive growth inhibition , whereas combination treatment with these agents synergistically inhibited the growth of +SA , MCF-7 and MDA-MB-231 mammary cancer cells , while similar treatment doses were found to have little or no effect on normal ( mouse CL-S1 and human MCF-10A ) mammary epithelial cell growth or viability . However , sesamin synergistic enhancement of γ-tocotrienol-induced anticancer effects was not found to be mediated from a reduction in γ-tocotrienol metabolism . Rather , combined treatment with subeffective doses of γ-tocotrienol and sesamin was found to induce G1 cell cycle arrest , and a corresponding decrease in cyclin D1 , CDK2 , CDK4 , CDK6 , phospho-Rb , and E2F1 levels , and increase in p27 and p16 levels . Additional studies showed that the antiproliferative effect of combination treatment did not initiate apoptosis or result in a decrease in mammary cancer cell viability . Taken together , these findings indicate that the synergistic antiproliferative action of combined γ-tocotrienol and sesamin treatment in mouse and human mammary cancer cells is cytostatic , not cytotoxic , and results from G1 cell cycle arrest .
|
[
0,
0,
0,
0,
1,
0,
0,
1,
1,
0
] |
23266736
|
22Rv1 is a common prostate cancer cell line used in xenograft mouse experiments as well as in vitro cell culture assays to study aspects of prostate cancer tumorigenesis . Recently , this cell line was shown to harbor multiple copies of a gammaretrovirus , called XMRV , integrated in its genome . While the original prostate cancer xenograft CWR22 is free of any retrovirus , subsequently generated cell lines 22Rv1 and CWR-R1 , carry this virus and additionally shed infectious gammaretroviral particles in their supernatant . Although XMRV most likely was generated by recombination events in cell culture this virus has been demonstrated to infect human cells in vitro and 22Rv1 as well as CWR-R1 cells are now considered biosafety 2 reagents . Here , we demonstrate that 22Rv1 cells with reduced retroviral transcription show reduced tumor angiogenesis and increased necrosis of the primary tumor derived from xenografted cells in scid mice when compared to the parental cell line . The presence of XMRV transcripts significantly increases secretion of osteopontin ( OPN ) , CXCL14 , IL13 and TIMP2 in 22Rv1 cells . Furthermore , these data are supported by in vitro cell invasion and differentiation assays . Collectively , our data suggest that the presence of XMRV transcripts at least partially contributes to 22Rv1 characteristics observed in vitro and in vivo with regard to migration , invasion and tumor angiogenesis . We propose that data received with 22Rv1 cells or equivalent cells carrying xenotropic gammaretroviruses should be carefully controlled including other prostate cancer cell lines tested for viral sequences .
|
[
1,
0,
0,
0,
0,
0,
1,
1,
0,
0
] |
22848758
|
Prenatal mortality is a prime concern for commercial swine industry in North America . Fetal losses occur throughout gestation but cluster in early ( and mid ( pregnancy . Adequate vascularization of the attachment site has emerged as a key factor contributing to fetal success . Since Insulin-Like Growth Factor ( IGF ) family members regulate angiogenesis in addition to promoting fetal development and growth , we hypothesized that conceptus success is governed by members of the IGF family . Using quantitative real time PCR , we analyzed expression of IGF family members ( IGF-I , IGF-II , IGF-I Receptor ( IGF-IR ) , IGF-IIR and their binding proteins , IGFBPs ) in matched maternal and fetal tissues of healthy and arresting conceptuses at gestation days ( gd ) 20 and 50 . IGF-II transcripts were 100 fold increased in both maternal and fetal tissues compared to IGF-I , but receptor transcripts were found in similar abundance irrespective of health status and gestation point . IGFBP3 was the most abundantly transcribed of the binding proteins . Using immunohistochemistry we confirmed the expression of IGF family members in maternal luminal and glandular epithelial cells , the endothelium of blood vessels and some scattered stromal cells . Our results suggest that IGF-I and II and their receptors are differentially expressed at the maternal and fetal components of the attachment site .
|
[
0,
0,
0,
0,
0,
0,
0,
0,
0,
0
] |
21685713
|
Optimal lymphocyte activation requires the simultaneous engagement of stimulatory and costimulatory receptors . Stimulatory immunoreceptors are usually composed of a ligand-binding transmembrane protein and noncovalently associated signal-transducing subunits . Here , we report that alternative splicing leads to two distinct NKG2D polypeptides that associate differentially with the DAP10 and KARAP ( also known as DAP12 ) signaling subunits . We found that differential expression of these isoforms and of signaling proteins determined whether NKG2D functioned as a costimulatory receptor in the adaptive immune system ( CD8+ T cells ) or as both a primary recognition structure and a costimulatory receptor in the innate immune system ( natural killer cells and macrophages ) . This strategy suggests a rationale for the multisubunit structure of stimulatory immunoreceptors .
|
[
0,
1,
0,
0,
0,
0,
0,
0,
0,
0
] |
12426565
|
Blind mole rats Spalax ( BMR ) are small subterranean rodents common in the Middle East . BMR is distinguished by its adaptations to life underground , remarkable longevity ( with a maximum documented lifespan of 21 y ) , and resistance to cancer . Spontaneous tumors have never been observed in spalacids . To understand the mechanisms responsible for this resistance , we examined the growth of BMR fibroblasts in vitro of the species Spalax judaei and Spalax golani . BMR cells proliferated actively for 7-20 population doublings , after which the cells began secreting IFN-\u03b2 , and the cultures underwent massive necrotic cell death within 3 d . The necrotic cell death phenomenon was independent of culture conditions or telomere shortening . Interestingly , this cell behavior was distinct from that observed in another long-lived and cancer-resistant African mole rat , Heterocephalus glaber , the naked mole rat in which cells display hypersensitivity to contact inhibition . Sequestration of p53 and Rb proteins using SV40 large T antigen completely rescued necrotic cell death . Our results suggest that cancer resistance of BMR is conferred by massive necrotic response to overproliferation mediated by p53 and Rb pathways , and triggered by the release of IFN-\u03b2 . Thus , we have identified a unique mechanism that contributes to cancer resistance of this subterranean mammal extremely adapted to life underground .
|
[
0,
0,
0,
1,
1,
0,
0,
1,
0,
0
] |
23129611
|
The potential of cytologically reconstructed barley line D-2946 to cope with the major lesions that hamper genome integrity , namely DNA single- and double-strand breaks was investigated . Strand breaks induced by \u03b3-rays and Li ions were assessed by neutral and alkaline comet assay . Repair capacity after bleomycin treatment was evaluated by agarose gel electrophoresis under neutral and alkaline conditions . Frequencies of radiation-induced chromosome aberrations were also determined . Results indicate that radiation-mediated constitutive rearrangement of the chromosome complement has led to a substantial modulation of the sensitivity of barley genome towards DNA strand breaks , produced by ionising radiation , Li ion implantation and bleomycin in an agent-specific manner , as well as of the clastogenic response to \u03b3-rays . Based on these findings , reconstructed barley karyotype D-2946 can be considered a candidate radio-sensitive line with reduced ability to maintain genome integrity with respect to both DNA and chromosomal damage .
|
[
0,
0,
0,
0,
0,
1,
0,
0,
0,
0
] |
23221036
|
The aim of this study was to investigate the inhibitory effects of rutaecarpine on DNA strand breaks and apoptosis induced by hydrogen peroxide ( H2O2 ) in murine Hepa-1c1c7 cells . Oxidative DNA damage was estimated by nuclear condensation assessment , fluorescence-activated cell sorting analysis , and Comet assay . Rutaecarpine inhibited cell death induced by 500 \u03bcM H2O2 , as assessed by 4',6-diamidino-2-phenylindole ( DAPI ) staining . Treatment with rutaecarpine reduced the number of DNA strand breaks induced by H2O2 , as assessed by DAPI staining and Comet assay , and increased quinone reductase , phosphatidylinositol 3-kinase , and pAkt protein levels , as assessed by western blotting .
|
[
0,
0,
0,
0,
0,
1,
0,
1,
0,
0
] |
24009839
|
BARD1 heterodimerizes with BRCA1 , forming an E3 ubiquitin ligase that functions at nuclear foci to repair DNA damage and the centrosome to regulate mitosis . We compared BARD1 recruitment at these structures using fluorescence recovery after photobleaching assays to measure YFP-BARD1 dynamics in live cells . In nuclei at ionizing radiation-induced foci , 20% of the BARD1 pool was immobile and 80% of slow mobility exhibiting a recovery time >500 s . In contrast , at centrosomes 83% of BARD1 was rapidly mobile with extremely fast turnover ( recovery time The faster exchange of BARD1 at centrosomes correlated with BRCA1-independent recruitment . We mapped key targeting sequences to a combination of the N and C-termini , and showed that mutation of the nuclear export signal reduced centrosome localization by 50% , revealing a role for CRM1 . Deletion of the sequence 128-550 increased BARD1 turnover at the centrosome , consistent with a role in transient associations . Conversely , the cancer mutation Q564H reduced turnover by 25% . BARD1 is one of the most highly mobile proteins yet detected at the centrosome , and in contrast to its localization at DNA repair foci , which requires dimerization with BRCA1 , targeting of BARD1 to the centrosome occurs prior to heterodimerization and its rapid turnover may provide a mechanism to regulate dimer formation .
|
[
0,
0,
0,
0,
0,
0,
0,
0,
0,
0
] |
21982881
|
Although interleukin-28A ( IL-28A ) is believed to have an antiviral effect , its role in tumor migration requires further examination . The present study was intended to verify the effect of IL-28A on the migration of UMUC-3 bladder cancer cells . IL-28A and its receptor IL-28AR1 mRNA were detected in UMUC-3 cells . Although exogenous IL-28A showed no effect on cell proliferation , a wound-healing migration assay showed that the migration of UMUC-3 cells was induced by IL-28A . Furthermore , treatment of the cells with IL-28A significantly promoted MMP-9 expression via binding activities of NF-κB and AP-1 . IL-28A also induced the activation of p38MAPK and Jak2-Stat2 signaling . Using the p38MAPK inhibitor SB203580 and the dominant-negative plasmid DN-p38 , we found evidence that the inhibition of p38MAPK signaling suppressed the effects of IL-28A including wound-healing migration and MMP-9 expression by activation of NF-κB and AP-1 binding in UMUC-3 cells . However , Jak-2 inhibition by AG490 did not affect IL-28A-induced migration of UMUC-3 cells . Collectively , we suggest for the first time that the p38MAPK pathway mediates IL-28A-induced cell migration through MMP-9 expression by activating NF-κB and AP-1 binding motifs .
|
[
1,
0,
0,
0,
0,
0,
0,
0,
1,
0
] |
22825757
|
Tumor-associated macrophages ( TAM ) have been shown to play an important role in tumor angiogenesis . The purpose of this study was to determine whether monocyte recruitment , activation and differentiation mediated by monocyte chemotactic protein-1 ( MCP-1 ) and macrophage colony stimulating factor ( M-CSF ) modulate the expression of the angiogenic factor , Interleukin ( IL)-8 . Isolated human peripheral blood monocytes secreted low basal levels of IL-8 . Incubation of monocytes with M-CSF or MCP-1 resulted in an up-regulation of IL-8 mRNA and protein expression . The differential expression of IL-8 by monocytes following MCP-1 and M-CSF treatments involved activation of the NFkB transcription factor . Further activation with lipopolysaccharide ( LPS ) caused an increase in IL-8 secretion in monocytes but not in monocyte-derived macrophages ( MDM ) . MDM-conditioned media significantly up-regulated IL-8 expression in human malignant melanoma cells in vitro . In summary , we demonstrated that MCP-1 and M-CSF , critical for monocyte recruitment , activation and differentiation , differentially regulate IL-8 expression and may play an important role in monocyte/macrophage-mediated tumor angiogenesis .
|
[
0,
0,
0,
0,
0,
0,
1,
0,
0,
0
] |
12494891
|
BACKGROUND Colorectal cancer is one of the main cancers in the Western world . About 90% of the deaths arise from formation of distant metastasis . The expression of the newly identified gene metastasis associated in colon cancer 1 ( MACC1 ) is a prognostic indicator for colon cancer metastasis . Here , we analyzed for the first time the impact of single nucleotide polymorphisms ( SNPs ) in the coding region of MACC1 for clinical outcome of colorectal cancer patients . Additionally , we screened met proto-oncogene ( Met ) , the transcriptional target gene of MACC1 , for mutations . METHODS We sequenced the coding exons of MACC1 in 154 colorectal tumors ( stages I , II and III ) and the crucial exons of Met in 60 colorectal tumors ( stages I , II and III ) . We analyzed the association of MACC1 polymorphisms with clinical data , including metachronous metastasis , UICC stages , tumor invasion , lymph node metastasis and patients ' survival ( n = 154 , stages I , II and III ) . Furthermore , we performed biological assays in order to evaluate the functional impact of MACC1 SNPs on the motility of colorectal cancer cells . RESULTS We genotyped three MACC1 SNPs in the coding region . Thirteen % of the tumors had the genotype cg ( rs4721888 , L31V ) , 48% a ct genotype ( rs975263 , S515L ) and 84% a gc or cc genotype ( rs3735615 , R804T ) . We found no association of these SNPs with clinicopathological parameters or with patients ' survival , when analyzing the entire patients ' cohort . An increased risk for a shorter metastasis-free survival of patients with a ct genotype ( rs975263 ) was observed in younger colon cancer patients with stage I or II ( P = 0.041 , n = 18 ) . In cell culture , MACC1 SNPs did not affect MACC1-induced cell motility and proliferation . CONCLUSION In summary , the identification of coding MACC1 SNPs in primary colorectal tumors does not improve the prediction for metastasis formation or for patients ' survival compared to MACC1 expression analysis alone . The ct genotype ( rs975263 ) might be associated with a reduced survival for younger colon cancer patients in early stages . However , further studies with larger sample sizes are needed .
|
[
1,
0,
0,
0,
0,
0,
0,
0,
0,
0
] |
22838389
|
The use of substrates containing well defined adducts at precise sites , is required to perform a careful analysis of the toxic and mutagenic potential of a lesion . As a first step in this direction the octamer 5'-d(CCGGCGGT) , containing the sequence of the codons 12 d(GGC) and 13 d(GGT) of the human H-ras gene , was reacted with the antitumoral drug cis-diamminedichloroplatinum(II) . The platinated products have been purified by HPLC . A first set of experiments , including enzymatic digestions with nuclease P1 followed by alkaline phosphatase and acid-catalysed hydrolysis , allowed us to determine which bases were engaged in the cis-DDP lesions . Our results indicate that only guanine residues were chelated with cisplatin to yield bifunctional adducts . Furthermore , by performing enzymatic digestions with phosphodiesterases , we have located the adducts with respect to the 5 ' end of the octamer . Among the purified and characterized platinated oligonucleotides , three present a particular interest , since we have shown here that the cis-d(GpG) adduct is precisely situated either at the d(GGC) or at the d(GGT) or at both sites of their sequence .
|
[
0,
0,
0,
0,
0,
1,
0,
0,
0,
0
] |
1480469
|
ZBP-89 ( ZNF148 ) is a Zinc finger Binding Protein of 89 kDa that binds GC-rich DNA elements . Originally , it was expression cloned using a DNA element mediating EGF regulation of the gastrin promoter . ZBP-89 functions as both a transcriptional activator and repressor . A variety of extracellular regulators including TGFbeta , retinoic acid and butyrate stimulate ZBP-89 gene expression . Butyrate activation of p21WAF1 is potentiated by ZBP-89 through the recruitment of the co-activator p300 , while chronic stimulation by butyrate increases ZBP-89 gene expression correlating with cell differentiation . ZBP-89 stimulates growth arrest and apoptosis through its ability to bind the p21WAF1 promoter or its ability to form protein-protein interactions with p53 . ZBP-89 protein is elevated in a variety of gastrointestinal cancers as well as the pancreas . In particular , ZBP-89 is normally expressed in pancreatic islets and ducts and in about 30% of pancreatic adenocarcinomas .
|
[
0,
0,
0,
0,
1,
0,
0,
1,
0,
0
] |
12622418
|
Pilocytic astrocytoma is commonly viewed as a benign lesion . However , disease onset is most prevalent in the first two decades of life , and children are often left with residual or recurrent disease and significant morbidity . The Hedgehog ( Hh ) pathway regulates the growth of higher WHO grade gliomas , and in this study , we have evaluated the activation and operational status of this regulatory pathway in pilocytic astrocytomas . Expression levels of the Hh pathway transcriptional target PTCH were elevated in 45% of tumor specimens analyzed ( ages 1-22 years ) and correlated inversely with patient age . Evaluation of a tissue array revealed oligodendroglioma-like features , pilomyxoid features , infiltration , and necrosis more commonly in specimens from younger patients ( below the median patient age of 10 years ) . Immunohistochemical staining for the Hh pathway components PTCH and GLI1 and the proliferation marker Ki67 demonstrated that patients diagnosed before the age of 10 had higher staining indices than those diagnosed after the age of 10 . A significant correlation between Ki67 and PTCH and GLI1 staining indices was measured , and 86% of Ki67-positive cells also expressed PTCH . The operational status of the Hh pathway was confirmed in primary cell culture and could be modulated in a manner consistent with a ligand-dependent mechanism . Taken together , these findings suggest that Hh pathway activation is common in pediatric pilocytic astrocytomas and may be associated with younger age at diagnosis and tumor growth .
|
[
0,
0,
0,
0,
0,
0,
0,
1,
1,
0
] |
20223881
|
The immune system has an important role in tumor appearance and spreading . One of the most efficient subpopulations of cytotoxic cells in the destruction of tumors are NK cells . NK cells are activated and increase their cytotoxic potential and modulate their cytokine production after treatment with IFNgamma , IL-12 , TNFalpha and IL-2 . The investigation of the activity of NK cells was performed on peripheral blood lymphocytes ( PBL ) of 16 healthy controls and of 40 patients with metastatic breast carcinoma . Modulation of NK cells was performed with IL-2 , IL-7 , IL-12 , TNFalpha , monoclonal antibodies ( mAb ) for TNFalpha and TNFalpha receptors type I and II , as well as with sera of healthy controls and patients with breast cancer in different clinical stages . Modulating effect of the applied factors after in vitro treatment of PBL was evaluated by the cytotoxic assay using 51chromium . Our results indicate that IL-2 significantly increased the activity of NK cells of controls and breast cancer patients . The sera of patients with advanced breast cancer significantly reduced NK cell activity . IL-7 , IL-12 and mAb for TNFalpha do not significantly change the activity of NK cells . The presence of anti-TNFalpha mAb did not change the inhibitory effect of the sera of breast cancer patients with advanced disease on the activity of NK cells of controls and patients with breast cancer . Blocking of TNFalpha Rcs with mAbs decrease the reactivity of NK cells for IL-2 . The treatment of breast cancer patients with advanced clinical stage of breast cancer with IL-2 , as an additional therapy , could be advantageous , as NK cells after this treatment increase their cytotoxic activity against tumor cells and can improve therapeutical results .
|
[
0,
1,
0,
0,
0,
0,
0,
0,
0,
0
] |
16078444
|
BACKGROUND Estrogen receptor β ( ERβ ) is the predominant ER in the colorectal epithelium , whose expression is greatly reduced in colorectal cancer compared with normal colon tissue . Recent in vitro studies suggested that ERβ may suppress tumor growth . No research was reported whether ERβ can be used as therapeutic agent for colon cancer . METHODS In this study , ERβ gene constructed into adenoviral ( Ad ) vectors was used to treat colon cancer HCT-116 cells alone or in combination with raloxifene . In vitro and in vivo studies were conducted to investigate the therapeutic effects of ERβ and raloxifene in HCT-116 cells . RESULTS Our results indicated that , although Ad-ERβ alone had no effect on the proliferation of HCT-116 cells , the combination of Ad-ERβ with raloxifene significantly inhibited the proliferation of HCT-116 cells . The apparently apoptotic induction effects may partly explain the cytotoxicity of the two agents . The results of the study of ERβ on migration and invasion of HCT-116 cells demonstrated that overexpression of ERβ significantly decreased cell migration and increased invasion of cells . The antitumor efficacies of ERβ as well as raloxifene were further investigated on HCT-116 tumor bearing mice . Results demonstrated that both Ad-ERβ and raloxifene individually inhibited tumor growth . The combination group showed the highest inhibitory efficiency compared with other three groups . CONCLUSION These findings demonstrated that combined administration of Ad-ERβ with raloxifene represents a promising colon cancer therapeutic strategy .
|
[
1,
0,
0,
0,
0,
0,
0,
1,
1,
0
] |
22398780
|
Despite insights into the molecular pathways regulating hypoxia-induced gene expression , it is not known which cell types accomplish oxygen sensing during neo-vasculogenesis . We have developed a humanized mouse model of endothelial and mesenchymal progenitor co-transplantation to delineate the cellular compartments responsible for hypoxia response during vasculogenesis . Mesenchymal stem/progenitor cells ( MSPCs ) accumulated nuclear hypoxia-inducible transcription factor ( HIF)-1α earlier and more sensitively than endothelial colony forming progenitor cells ( ECFCs ) in vitro and in vivo . Hypoxic ECFCs showed reduced function in vitro and underwent apoptosis within 24h in vivo when used without MSPCs . Surprisingly , only in MSPCs did pharmacologic or genetic inhibition of HIF-1α abrogate neo-vasculogenesis . HIF deletion in ECFCs caused no effect . ECFCs could be rescued from hypoxia-induced apoptosis by HIF-competent MSPCs resulting in the formation of patent perfused human vessels . Several angiogenic factors need to act in concert to partially substitute mesenchymal HIF-deficiency . Results demonstrate that ECFCs require HIF-competent vessel wall progenitors to initiate vasculogenesis in vivo and to bypass hypoxia-induced apoptosis . We describe a novel mechanistic role of MSPCs as oxygen sensors promoting vasculogenesis thus underscoring their importance for the development of advanced cellular therapies .
|
[
0,
0,
0,
0,
0,
0,
1,
1,
0,
0
] |
22970226
|
Human papillomavirus type 16 ( HPV16 ) E6 and E7 are selectively retained and expressed in HPV16-associated human genital tumors . E6 is active in several cell culture assays , including transformation of NIH 3T3 cells , trans activation of the adenovirus E2 promoter , and cooperation with E7 to immortalize normal human keratinocytes . Biochemically , the HPV16 E6 protein has been shown to bind to tumor suppressor protein p53 in vitro and induce its degradation in a rabbit reticulocyte lysate . To examine the relationship between the various biological activities of E6 and inactivation of p53 , we tested the abilities of dominant negative mutants of p53 to substitute functionally for E6 in the three cell culture assays . While wild-type p53 inhibited keratinocyte proliferation , both mouse and human mutant p53s , in conjunction with E7 , increased proliferation of the keratinocytes , resulting in generation of immortalized lines . However , in contrast to E6 , mutant p53 was unable to induce transformation or trans activate the adenovirus E2 promoter in NIH 3T3 cells . These results suggest that inactivation of wild-type p53 is necessary for HPV-induced immortalization of human keratinocytes and that different or additional activities are required for E6-dependent transformation and trans activation of NIH 3T3 cells .
|
[
0,
0,
0,
1,
0,
0,
0,
0,
0,
0
] |
1318401
|
It is well established that blocking the interaction of EGFR with growth factors leads to the arrest of tumor growth , resulting in tumor cell death . ER414 is a human monoclonal antibody ( mAb ) derived by guided selection of the mouse mAb A13 . The ER414 exhibited a lower affinity and , as a result , lower efficacy of inhibition of the EGF-mediated tyrosine phosphorylation of EGFR when compared with mAb A13 and cetuximab . We performed a stepwise in vitro affinity maturation to improve the affinity of ER414 . We obtained a 3D model of ER414 to identify the amino acids in the CDRs that needed to be mutated . Clones were selected from the phage library with randomized amino acids in the CDRs and substitution of amino acids in the HCDR3 and LCDR1 of ER414 led to improved affinity . A clone , H3-14 , with a increased affinity , was selected from the HCDR3 randomized library . Then three clones , ER2 , ER78 and ER79 , were selected from the LCDR1 randomized library based on the H3-14 but did not show further increased affinities compared to that of H3-14 . Of the three , ER2 was chosen for further characterization due to its better expression than others . We successfully performed affinity maturation of ER414 and obtained antibodies with a similar affinity as cetuximab . And antibody from an affinity maturation inhibits the EGF-mediated tyrosine phosphorylation of EGFR in a manner similar to cetuximab .
|
[
0,
0,
0,
0,
0,
0,
0,
0,
0,
0
] |
23091439
|
BACKGROUND Surgical procedures such as liver resection and liver transplantation are the first-line treatments for hepatocellular carcinoma ( HCC ) patients . However , the high incidence of tumor recurrence and metastasis after liver surgery remains a major problem . Recent studies have shown that hepatic ischemia-reperfusion ( I/R ) injury and endothelial progenitor cells ( EPCs ) contribute to tumor growth and metastasis . We aim to investigate the mechanism of FTY720 , which was originally applied as an immunomodulator , on suppression of liver tumor metastasis after liver resection and partial hepatic I/R injury . METHODOLOGY/PRINCIPAL FINDINGS An orthotopic liver tumor model in Buffalo rat was established using the hepatocellular carcinoma cell line McA-RH7777 . Two weeks after orthotopic liver tumor implantation , the rats underwent liver resection for tumor-bearing lobe and partial hepatic I/R injury . FTY720 ( 2 mg/kg ) was administered through the inferior caval vein before and after I/R injury . Blood samples were taken at days 0 , 1 , 3 , 7 , 14 , 21 and 28 for detection of circulating EPCs ( CD133+CD34+ ) . Our results showed that intrahepatic and lung metastases were significantly inhibited together with less tumor angiogenesis by FTY720 treatment . The number of circulating EPCs was also significantly decreased by FTY720 treatment from day 7 to day 28 . Hepatic gene expressions of CXCL10 , VEGF , CXCR3 , CXCR4 induced by hepatic I/R injury were down-regulated in the treatment group . CONCLUSIONS/SIGNIFICANCE FTY720 suppressed liver tumor metastasis after liver resection marred by hepatic I/R injury in a rat liver tumor model by attenuating hepatic I/R injury and reducing circulating EPCs .
|
[
1,
0,
0,
0,
0,
0,
1,
0,
0,
0
] |
22384233
|
The conserved eukaryotic DNA replication protein ORC1 is one of the constituents of pre-replication complexes that assemble at or very near origins prior to replication initiation . ORC1 has been shown to be constitutively nuclear in Leishmania major . This study investigates the sequences involved in nuclear localization of ORC1 in Leishmania donovani , the causative agent of visceral leishmaniasis . Nuclear localization signals ( NLSs ) have been reported in only a few Leishmania proteins . Functional analyses have delineated NLSs to regions of amino acids in length in the tyrosyl DNA phosphodiesterase I and type II DNA topoisomerase of L. donovani , and in the L. major kinesin KIN13-1 . Using a panel of site-directed mutations we have identified a sequence essential for nuclear import of LdORC1 . This sequence at the N terminus of the protein comprises residues 2-5 ( KRSR ) , with K2 , R3 and R5 being crucial . Independent mutation of the K2 residue causes exclusion of the protein from the nucleus , while mutating the R5 residue leads to diffusion of the protein throughout the cell . This sequence , however , is insufficient for targeting a heterologous protein ( \u03b2-galactosidase ) to the nucleus . Analysis of additional ORC1 mutations and reporter constructs reveals that while the highly basic tetra-amino acid sequence at the N terminus is essential for nuclear localization , the ORC1 NLS in its entirety is more complex , and of a distributive character . Our results suggest that nuclear localization signalling sequences in Leishmania nuclear proteins are more complex than what is typically seen in higher eukaryotes .
|
[
0,
0,
0,
0,
0,
0,
0,
0,
0,
0
] |
22575896
|
Ionizing radiation is a potent inducer of DNA damage because it causes single- and double-strand breaks , alkali-labile sites , base damage , and crosslinks . The interest in ionizing radiation is due to its environmental and clinical implications . Single-strand breaks , which are the initial damage induced by a genotoxic agent , can be used as a biomarker of exposure , whereas the more biologically relevant double-strand breaks can be analyzed to quantify the extent of damage . In the present study the effects of 137CS gamma-radiation at doses of 1 , 5 , and 10 Gray on DNA and subsequent repair by C3H10T1/2 cells ( mouse embryo fibroblasts ) were investigated . Two versions of the comet assay , a sensitive method for evaluating DNA damage , were implemented : the alkaline one to detect single-strand breaks , and the neutral one to identify double-strand breaks . The results show a good linear relation between DNA damage and radiation dose , for both single-strand and double-strand breaks . A statistically significant difference with respect to controls was found at the lowest dose of 1 Gy . Heterogeneity in DNA damage within the cell population was observed as a function of radiation dose . Repair kinetics showed that most of the damage was repaired within 2 h after irradiation , and that the highest rejoining rate occurred with the highest dose ( 10 Gy ) . Single-strand breaks were completely repaired 24 h after irradiation , whereas residual double-strand breaks were still present . This finding needs further investigation .
|
[
0,
0,
0,
0,
0,
1,
0,
0,
0,
0
] |
12484548
|
Background . Over the past ten years oncological outcomes achieved by local excision techniques ( LETs ) as the sole treatment for early stages of rectal cancer ( ESRC ) have been often disappointing . The reasons for these poor results lie mostly in the high risk of the disease's diffusion to local-regional lymph nodes even in ESRC . Aims . This study aims to find the correct indications for LET in ESRC taking into consideration clinical-pathological features of tumours that may reduce the risk of lymph node metastasis to zero . Methods . Systematic literature review and meta-analysis of casistics of ESRC treated with total mesorectal excision with the aim of identifying risk factors for nodal involvement . Results . The risk of lymph node metastasis is higher in G ≥ 2 and T ≥ 2 tumours with lymphatic and/or vascular invasion . Other features which have not yet been sufficiently investigated include female gender , TSM stage >1 , presence of tumour budding and/or perineural invasion . Conclusions . Results comparable to radical surgery can be achieved by LET only in patients with T(1) N(0) G(1) tumours with low-risk histological features , whereas deeper or more aggressive tumours should be addressed by radical surgery ( RS ) .
|
[
1,
0,
0,
0,
0,
0,
0,
0,
0,
0
] |
22778940
|
Telomerase is a ribonucleoprotein consisting of a catalytic subunit , the telomerase reverse transcriptase , TERT , and an integrally associated RNA , TR , which contains a template for the synthesis of short repetitive G-rich DNA sequences at the ends of telomeres . Telomerase can repetitively reverse transcribe its short RNA template , acting processively to add multiple telomeric repeats onto the same DNA substrate . The contribution of enzyme processivity to telomere length regulation in human cells is not well characterized . In cancer cells , under homeostatic telomere length-maintenance conditions , telomerase acts processively , while under nonequilibrium conditions , telomerase acts distributively on the shortest telomeres . To investigate the role of increased telomerase processivity on telomere length regulation in human cells with limited lifespan that are dependent on human TERT ( hTERT ) for lifespan extension and immortalization , we mutated the leucine at position 866 in the reverse transcriptase C motif of hTERT to a tyrosine ( L866Y ) , which is the amino acid found at a similar position in HIV-1 reverse transcriptase . We report that , similar to the previously reported ' gain of function ' Tetrahymena telomerase mutant ( L813Y ) , the human telomerase variant displays increased processivity. hTERT-L866Y , like wild-type hTERT can immortalize and extend the lifespan of limited lifespan cells . Moreover , hTERT-L866Y expressing cells display heterogenous telomere lengths , telomere elongation , multiple telomeric signals indicative of fragile sites and replicative stress , and an increase in short telomeres , which is accompanied by telomere trimming events . Our results suggest that telomere length and homeostasis in human cells may be regulated by telomerase enzyme processivity .
|
[
0,
0,
0,
1,
0,
0,
0,
0,
0,
0
] |
23178942
|
BACKGROUND The current staging system provides an anatomical classification of lung tumors ; its secondary purpose is to allow the prognostic stratification of patients into homogeneous groups after surgery . In this work , intratumoral perineural invasion , lymphatic and blood vessel invasion together with the necrosis content of the tumor exclusive of the non-small cell cancer staging system were studied . METHODS During a 4-year period , 152 patients operated for non-small cell lung cancer ( NSCLC ) at our hospital were analyzed . Mean age of patients was 55.7 +/- 10.1 years . RESULTS Overall 5-year survival was 42.2 % . Mediastinal lymph node involvement , tumor size , incomplete resection , pneumonectomy , presence of necrosis and perineural invasion were significant prognosticators ( P = 0.03 , 0.04 , 0.0001 , 0.046 , 0.0246 , < 0.0001 , respectively ) . Multivariate analysis revealed that N status , perineural invasion , and the presence of necrosis were independent prognostic factors ( P = 0.006 , P = 0.001 , P = 0.001 , respectively ) . Patients who had stage I tumor with necrosis and perineural invasion had a lower survival rate than those with stage IIIA tumor without these histopathological features ( P = 0.04 ) . The presence of these histopathological characteristics in stage IIIA patients was a sign of a poorer prognosis ( P = 0.0001 ) . CONCLUSIONS Perineural invasion and the presence of necrosis independently indicated a dismal prognosis and their prognostic power is comparable to those of the TNM classification . These factors could be candidates for better survival stratification and the indicators of the need for adjuvant therapy in early stage lung cancer patients .
|
[
1,
0,
0,
0,
0,
0,
0,
1,
0,
0
] |
20333571
|
Dendritic cells ( DCs ) are key regulators of innate and acquired immunity . The maturation of DCs is directed by signal transduction events downstream of toll-like receptors ( TLRs ) and other pattern recognition receptors . Here , we demonstrate that , in mouse DCs , TLR agonists stimulate a profound metabolic transition to aerobic glycolysis , similar to the Warburg metabolism displayed by cancer cells . This metabolic switch depends on the phosphatidyl inositol 3'-kinase/Akt pathway , is antagonized by the adenosine monophosphate ( AMP)-activated protein kinase ( AMPK ) , and is required for DC maturation . The metabolic switch induced by DC activation is antagonized by the antiinflammatory cytokine interleukin-10 . Our data pinpoint TLR-mediated metabolic conversion as essential for DC maturation and function and reveal it as a potential target for intervention in the control of excessive inflammation and inappropriately regulated immune responses .
|
[
0,
0,
1,
0,
0,
0,
0,
0,
0,
1
] |
20351312
|
The telomerase activity and the senescence profile of cultured breast fibroblasts from normal human interstitial and malignant stromal tissue were studied in comparison with their proliferation and differentiation pattern . Fibroblasts were grown either in the presence or absence of a conditioned medium ( CM ) obtained from cultures of the oestrogen receptor-positive breast cancer MCF-7 cell line . At different passages ( from the 2nd up to the 48th ) , fibroblasts were examined for the telomerase activity by the Telomerase Repeats Amplification Protocol ( TRAP ) assay , for proliferation profile by Ki-67 antigen expression , and the myofibroblast or smooth muscle cell-like differentiation pattern by immunofluorescence with monoclonal antibodies specific for smooth muscle markers . Serial passages of fibroblasts from normal or tumour breast reveal that the relationship between the levels of telomerase activity and phenotypic/proliferation profile changes with cell subcultivation in a different manner in the two cell populations . The fibroblasts from normal tissue completed 12 passages in a CM-independent way prior to senescence whereas fibroblasts from tumour stroma senescence were attained after 48 passages . These cells showed a marked decrease of telomerase activity , growth rate and smooth muscle alpha-actin expressing myofibroblasts after the 32nd passage . CM treatment of this fibroblast population induces a decline in the myofibroblast content , which precedes the changes in telomerase activity . Passaged fibroblasts from normal breast tissue can be converted to myofibroblasts upon CM treatment whereas those from tumour stroma were CM-insensitive . Taken together our data suggest that a heterogeneous fibroblast population with different life span is activated/recruited in the breast interstitium and poses the problem of a unique activation/recruitment of fibroblasts in neoplastic conditions .
|
[
0,
0,
0,
1,
0,
0,
0,
0,
0,
0
] |
12814188
|
Comparative mutagenesis studies of N-(2'-deoxyguanosin-8-yl)-2-acetylaminofluorene ( dG-AAF ) and N-(2'-deoxyguanosin-8-yl)-2-aminofluorene ( dG-AF ) adducts positioned in the Nar I restriction enzyme site were performed using Escherichia coli ( E. coli ) and simian kidney ( COS-7 ) cells . Oligodeoxynucleotides ( (5)(')TCCTCG(1)G(2)CG(3)CCTCTC ) containing a recognition sequence for the Nar I restriction enzyme were modified site-specifically with dG-AAF or dG-AF . Modified and unmodified oligomers inserted into single-stranded phagemid shuttle vectors were used to transform E. coli or to transfect COS-7 cells . Following replication in host cells , progeny plasmids were recovered and analyzed for mutations . In SOS-induced E. coli , dG-AAF primarily induced one- and two-base deletions . The mutational frequency varied , depending on the position modified in the Nar I site ; 91% two-base deletions were observed at G(3) , while 8.4% and 2.8% deletions were detected at G(2) and G(1) , respectively . In contrast , dG-AF at any position in the Nar I site failed to produce deletions , generating primarily G --> T transversions ( mutational frequency , 7.6-8.4% ) . In COS-7 cells , both dG-AAF and dG-AF primarily induced G --> T transversions . Mutation frequencies for dG-AAF were 9.4-24% , the highest values being at G(1) and G(3) . Mutation frequencies for dG-AF were 9.3-21% , the higher value at G(2) . We conclude from this study that the mutation potential of dG-AAF and dG-AF depends on the structure of the adduct , the sequence context of the lesion , and the host cell used for the experiment .
|
[
0,
0,
0,
0,
0,
1,
0,
0,
0,
0
] |
12450390
|
Recent studies have demonstrated that n-3 polyunsaturated fatty acids such as eicosapentaenoic acid ( EPA ) are able to suppress cell proliferation and inhibit tumor growth . The objective of our study was to investigate the influence of a high dose EPA on the development of the tumor phenotype in ataxia-telangiectasia mutated ( Atm)-deficient mice , a genetic cancer model that is associated with increased levels of oxidative stress . We analyzed toxicity , proliferation , cell-cycle progression , and apoptosis of EPA in vitro and latency to tumorigenesis in vivo . Because of the impact of reactive oxygen species ( ROS ) on the tumor incidence in ataxia telangiectasia ( AT ) , we further analyzed the effect of EPA on the generation of ROS and oxidative DNA damage ( ODD ) . EPA effectively inhibited proliferation , altered cell-cycle progression , and induced apoptosis of tumor cells ( AT-4 ) . EPA showed no effect on the latency to tumorigenesis in Atm-deficient mice . EPA treatment was accompanied by a significant increase of ROS and ODD . Our results demonstrate the antiproliferative effect of EPA on tumor cells by alteration of cell-cycle progression and induction of apoptosis in vitro . On the other hand , EPA treatment of Atm-deficient mice led to the formation of ROS and accumulation of ODD that might have abrogated the anticarcinogenic effect caused by EPA .
|
[
0,
0,
0,
0,
1,
0,
0,
1,
1,
0
] |
20574919
|
Expression of angiogenic factors is upregulated in hyperplastic mucosa adjacent to colon cancer , and this upregulation is closely associated with cancer growth and metastasis . We investigated the role of histone acetylation in vascular endothelial growth factor ( VEGF ) expression in hyperplastic mucosa adjacent to orthotopic colon cancer in mice . In the hyperplastic mucosa adjacent to KM12SM tumor in the cecum of athymic mice , VEGF upregulation was associated with hypoxia-inducible factor ( HIF)-1alpha induction . The hyperplastic mucosa also showed hypoacetylation of histone H4 and reduction of both p53 and von Hippel-Lindau ( VHL ) proteins . To examine the effects of growth factors and cytokines on histone acetylation and levels of p53 , VHL and HIF-1alpha , the rat intestinal epithelial cell line IEC6 was treated with epidermal growth factor ( EGF ) and interleukin ( IL)-15 for 35 days . Acetylated histone H4 , p53 protein and ubiquitinated protein levels were reduced , whereas HIF-1alpha production was upregulated in EGF- and IL-15-treated IEC6 cells . These findings suggest that EGF- or IL-15-induced histone H4 hypoacetylation is associated with repression of p53 and VHL genes in intestinal epithelial cells . The subsequent suppression of protein ubiquitination leads to upregulation of VEGF production by HIF-1alpha retention .
|
[
0,
0,
0,
0,
0,
0,
1,
0,
1,
0
] |
12865631
|
Maintaining the integrity of the cell cycle is critical for ensuring that cells only undergo DNA replication and proliferation under controlled conditions in response to discrete stimuli . One mechanism by which the fidelity of this process is guaranteed is through the activation of cell cycle checkpoints . The mitotic spindle checkpoint , which is regulated by Aurora B kinase , ensures proper kinetochore attachment to chromosomes leading to equal distribution of chromosomes to daughter cells . We demonstrated that the mitogen-activated protein kinase ( MAPK ) cascade regulates mitotic progression and the spindle checkpoint . As demonstrated by immunofluorescence at kinetochores , depletion of Raf Kinase Inhibitory Protein ( RKIP ) , an inhibitor of Raf/MEK/ERK signaling , causes an increase in MAPK activity that inhibits Aurora B kinase activity . By monitoring mitotic index and transit time from nuclear envelope breakdown to anaphase , we demonstrated that RKIP depletion leads to a defective spindle checkpoint and genomic instability , particularly in response to drugs that disrupt microtubule function .
|
[
0,
0,
0,
0,
0,
1,
0,
0,
1,
0
] |
20812004
|
BACKGROUND Intracystic papillary carcinoma ( IPC ) of the breast is a rare form of noninvasive breast cancer . An appreciation of associated pathology with IPC may be critical in surgical decision-making . METHODS The medical records of all patients with IPC treated between 1985 and 2001 were retrospectively reviewed . Three patient groups were identified according to the pathologic features of the primary tumor : IPC alone , IPC with associated ductal carcinoma in situ ( DCIS ) , and IPC with associated invasion with or without DCIS . Types of treatment and outcomes were compared between groups . RESULTS Forty patients were treated for IPC during the study period . Fourteen had pure IPC , 13 had IPC with DCIS , and 13 had IPC with invasion . The incidence of recurrence and the likelihood of dying of IPC did not differ between the three groups regardless of the type of surgery ( mastectomy or segmental mastectomy ) performed and whether radiation therapy was administered . The disease-specific survival rate was 100% . CONCLUSIONS When IPC is identified , it is frequently associated with DCIS and or invasion . Standard therapy should be based on associated pathology . The role of radiation therapy in pure IPC remains to be determined .
|
[
1,
0,
0,
0,
0,
0,
0,
0,
0,
0
] |
12383904
|
Prostate cancer ( PCA ) is the most common histological malignancy and the second leading cause of cancer deaths among North American men . There has been considerable interest in the chemopreventative properties of selenium . In this study , we assessed whether selenium inhibits cell growth and associated cell cycle regulatory proteins . Human PCA cells ( LNCaP , PC3 , PC3-AR2 , and PC3-M ) were incubated with and without selenium ( Seleno-DL-methionine , 150 microM ) for 24 , 48 , and 72 h . Cells were fixed and stained with propidium iodide for flow cytometry analysis . In parallel experiments , total protein was extracted , immunoprecipitated with cyclin E antibody , and analyzed by Western blot for the expression of cell cycle markers . Treatment with selenium caused G1 arrest and an 80% reduction in the S phase of LNCaP with no effect on PC3 . However , PC3 cells transfected with the androgen receptor ( PC3-AR2 ) exhibited a G2/M arrest and a marked reduction ( 57% ) in the S phase during cell cycle progression . In the analysis of cell cycle regulatory molecules , selenium-treated cells demonstrated a significant induction of cyclin-dependent kinase inhibitors Cip1/p21 and Kip1/p27 . These data suggest that selenium possesses strong antiproliferative properties in regard to human PCA . This effect appears to be dependent on the presence of a functioning androgen receptor . This provides a theoretical basis for Phase III studies of selenium in PCA prevention .
|
[
0,
0,
0,
0,
1,
0,
0,
0,
1,
0
] |
11980647
|
Previous studies with selenium and/or vitamin E in prostate carcinogenesis animal models have been negative , but these models may not involve oxidative stress mechanisms . In this study , we examined the potential of selenomethionine and alpha-tocopherol to modulate prostate cancer development in the testosterone plus estradiol-treated NBL rat , a model that does involve sex hormone-induced oxidative stress mechanisms and prostatic inflammation . One week following the implantation with hormone-filled Silastic implants , rats were fed diets containing l-selenomethionine ( 1.5 or 3.0 mg/kg ) , DL-alpha-tocopherol acetate ( 2,000 or 4,000 mg/kg ) , or a natural ingredient control diet ( NIH-07 ) . The development of prostate carcinomas was not affected by dietary treatment with either agent . Food intake , body weight , and mortality were also not affected . The high dose of selenomethionine reduced the severity of epithelial dysplasia in the lateral prostate that was not associated with inflammation , and alpha-tocopherol reduced in a dose-related fashion the incidence of marked inflammation and marked epithelial dysplasia in the lateral prostate , regardless of whether these lesions were associated with inflammation. alpha-Tocopherol significantly increased the incidence of adenocarcinomas of the mammary glands at both dietary concentrations . Collectively , our findings suggest that selenomethionine and alpha-tocopherol supplementation does not prevent prostate cancer in rats fed diets with nutritionally adequate levels of selenium and vitamin E. Importantly , the results of the current animal studies and those reported previously were fully predictive of the outcome of the Selenium and Vitamin E Cancer Prevention Trial .
|
[
0,
0,
0,
0,
0,
0,
0,
0,
0,
1
] |
20179302
|
Human diploid fibroblasts have a limited life span in vitro , and spontaneous immortalization is an extremely rare event . We have used transformation of human diploid fibroblasts by an origin-defective simian virus 40 genome to develop series of genetically matched immortal cell lines to analyze immortalization . Comparison of a preimmortal transformant ( SVtsA/HF-A ) with its uncloned and cloned immortalized derivatives ( AR5 and HAL ) has failed to reveal any major alteration involving the simian virus 40 genome . Karyotypic analysis , however , demonstrated that all of the immortal cell lines in this series have alterations of chromosome 6 involving loss of the portion distal to 6q21 . The karyotypic analysis was corroborated by DNA analyses . Southern analysis demonstrated that only one copy of three proto-oncogene loci ( ros1 , c-myb , and mas1 ) on 6q was retained in immortal cells . Polymerase chain reaction analysis of the microsatellite polymorphism at 6q22 ( D6S87 ) showed loss of heterozygosity . In addition , elevated expression of c-myb ( 6q22-23 ) was observed . We hypothesize that the region at and/or distal to 6q21 plays a role in immortalization , consistent with the presence of a growth suppressor gene .
|
[
0,
0,
0,
1,
0,
0,
0,
0,
0,
0
] |
1373811
|
Atherosclerosis ( As ) is now widely appreciated to represent a chronic inflammatory reaction of the vascular wall in response to dyslipidemia and endothelial distress involving the inflammatory recruitment of leukocytes and the activation of resident vascular cells . MicroRNAs ( miRNAs ) are a group of endogenous , small ( nucleotides in length ) non-coding RNA molecules , which function specifically by base pairing with mRNA of genes , thereby induce translation repressions of the genes within metazoan cells . Recently , the function of miR-27 , one of the miRNAs , in the initiation and progression of atherosclerosis has been identified . In vivo and in vitro studies suggest that miR-27 may serve as a diagnostic and prognostic marker for atherosclerosis . More recently , studies have identified important roles for miR-27 in angiogenesis , adipogenesis , inflammation , lipid metabolism , oxidative stress , insulin resistance and type 2 diabetes , etc . In this review , we focus on the role of miR-27 in the development of vulnerable atherosclerotic plaques , potential as a disease biomarker and novel therapeutic target in atherosclerosis .
|
[
0,
0,
0,
0,
0,
0,
0,
0,
0,
0
] |
22307089
|
Doxorubicin ( DOX ) is one of the most powerful and widely prescribed chemotherapeutic agents to treat divergent human cancers . However , the clinical use of DOX is restricted due to its severe cardiotoxic side-effects . There has been ongoing search for cardioprotectants against DOX toxicity . Inorganic nitrate has emerged as a bioactive compound that can be reduced into nitrite and nitric oxide in vivo and in turn plays a therapeutic role in diseases associated with nitric oxide insufficiency or dysregulation . In this review , we describe a novel concept of using dietary supplementation of inorganic nitrate to reduce DOX-induced cardiac cellular damage and dysfunction , based on our recent promising studies in a mouse model of DOX cardiotoxicity . Our data show that chronic oral ingestion of sodium nitrate , at a dose equivalent to of the Acceptable Daily Intake of the World Health Organization , alleviated DOX-induced left ventricular dysfunction and mitochondrial respiratory chain damage . Such cardioprotective effects were associated with reduction of cardiomyocyte necrosis/apoptosis , tissue lipid peroxidation , and mitochondrial H(2)O(2) generation following DOX treatment . Furthermore , proteomic studies revealed enhanced cardiac expression of mitochondrial antioxidant enzyme - peroxiredoxin 5 in the nitrate-treated animals . These studies suggest that inorganic nitrate could be an inexpensive therapeutic agent for long-term oral administration in preventing DOX-induced cardiac toxicity and myopathy during the prolonged pathological process . Future clinical trials in the cancer patients undergoing DOX chemotherapy are warranted to translate these experimental findings into an effective new therapy in preventing the DOX-induced cardiomyopathy .
|
[
0,
0,
0,
0,
0,
0,
0,
0,
0,
0
] |
22484629
|
Hexavalent chromium ( Cr(VI) ) compounds are known human carcinogens associated with the incidence of lung cancer . Although a direct correlation between Cr(VI) exposure and lung cancer has been established , several studies aimed at generating animal models for Cr(VI) have yielded inconsistent data that do not affirmatively support findings from epidemiologic studies . Because the lack of a good animal model has hindered the identification of molecular mechanisms involved in Cr(VI) exposure , we developed an in vitro model that facilitates mechanistic studies of Cr(VI)-induced carcinogenesis . We report here that long-term exposure to Cr(VI) leads to the malignant transformation of nontumorigenic human lung epithelial cells . Cr(VI)-transformed cells exhibited loss of contact inhibition , colony formation , and increased rates of cell invasion , migration , and proliferation , as compared with passage-matched control cells . Cr(VI)-transformed cells evaded apoptosis by a mechanism involving S-nitrosylation and stabilization of Bcl-2 protein in a nitric oxide-dependent manner . This study establishes an important in vitro model that facilitates mechanistic studies of Cr(VI)-induced carcinogenesis , and elucidates a novel mechanism that causes apoptosis-resistant malignant transformation of nontumorigenic lung cells in response to a human carcinogen .
|
[
1,
0,
0,
0,
1,
0,
0,
1,
0,
0
] |
19556603
|
Semaphorin 5A , a member of semaphorin family , was originally identified as axonal guidance factor functioning during neuronal development . Previously , we showed that the expression of semaphorin 5A might contribute to the metastasis of gastric cancer . However , its functional roles and mechanism(s) in invasion and metastasis of gastric cancer remain unclear . By using human gastric caner cell lines Parental SGC7901 , SGC7901-siScrambled and SGC7901-siSema 5A , we found that semaphorin 5A significantly promoted the invasive and metastatic abilities of gastric cancer cell in vitro . Semaphorin 5A increased the expression of MMP9 by activating phosphorylated ErK1/2 in gastric cancer cell . Furthermore , MEK inhibitor PD98059 and MMP9 antibody ( Ab ) significantly inhibited in vitro invasive and metastatic abilities induced by semaphorin 5A . Taken together , the present work revealed a novel function of semaphorin 5A that the existence of semaphorin 5A could promote invasion and metastasis of gastric cancer by regulating MMP9 expression , at least partially , via the MEK/ERKs signal transduction pathway . Semaphorin 5A and its regulated molecules could be the potential targets for cancer therapy .
|
[
1,
0,
0,
0,
0,
0,
0,
0,
1,
0
] |
22821546
|
Lowering the threshold of cellular senescence , the process employed by cells to thwart abnormal cell proliferation , though inhibition of CDK2 or Skp2 ( regulator of CDK inhibitors ) has been recently suggested as a potential avenue for cancer treatment . In this study , we employ a published mathematical model of G1/S transition involving the DNA-damage signal transduction pathway to conduct carefully constructed computational experiments to highlight the effectiveness of manipulating cellular senescence in inhibiting damaged cell proliferation . We first demonstrate the suitability of the mathematical model to explore senescence by highlighting the overlap between senescence pathways and those involved in G1/S transition and DNA damage signal transduction . We then investigate the effect of CDK2 deficiency on senescence in healthy cells , followed by effectiveness of CDK2 deficiency in triggering senescence in DNA damaged cells . For this , we focus on the behaviour of CycE , whose peak response indicates G1/S transition , for several reduced CDK2 levels in healthy as well as two DNA-damage conditions to calculate the probability ( \u03b2 ) or the percentage of CDK2 deficient cells passing G1/S checkpoint ( (1-\u03b2) indicates level of senescence ) . Results show that 50% CDK2 deficiency can cause senescence in all healthy cells in a fairly uniform cell population ; whereas , most healthy cells ( \u224867% ) in a heterogeneous population escape senescence . This finding is novel to our study . Under both low- and high-DNA damaged conditions , 50% CDK deficiency can cause 65% increase in senescence in a heterogeneous cell population . Furthermore , the model analyses the relationship between CDK2 and its CKIs ( p21 , p27 ) to help search for other effective ways to bring forward cellular senescence . Results show that the degradation rate of p21 and initial concentration of p27 are effective in lowering CDK2 levels to lower the senescence threshold . Specifically , CDK2 and p27 are the most effective in triggering senescence while p21 having a smaller influence . While receiving experimental support , these findings specify in detail the inhibitory effects of CKIs . However , simultaneous variation of CDK2 and CKIs produces a dramatic reduction of damage cells passing the G1/S with CDK2&p27 combination causing senescence in almost all damaged cells . This combined effect of CDK2&CKIs on senescence is a novel contribution in this study . A review of the crucial protein complexes revealed that the concentration of active CycE/CDK2-p that controls cell cycle arrest provides support for the above findings with CycE/CDK2-p undergoing the largest reduction ( over 100% ) under the combined CDK2&CKI conditions leading to the arrest of most of the damaged cells . Our study thus provides quantitative assessments for the previously published qualitative findings on senescence and highlights new avenues for bringing forward senescence bar .
|
[
0,
0,
0,
1,
1,
1,
0,
0,
0,
0
] |
23254306
|
An accidental exposure of six workers to ethylene oxide ( EO ) provided the rationale for a biomonitoring and follow-up study , whose aim was to analyse protein adduct kinetics and examine the differentiation between accidental and environmental exposure , e.g. , from tobacco smoke . For this purpose , the decrease in the concentration of the haemoglobin adduct N-2-hydroxyethylvaline ( HEV ) was followed during a five-month period after the accident , together with N-2-cyanoethylvaline ( CEV ) and urinary cotinine , two well-established biomarkers for smoking . The follow-up study showed that EO adduct concentrations significantly increased after a short but presumably high exposure . Initial biomonitoring revealed HEV levels above 500 pmol g(-1) globin in all cases , with a maximum of about 2,400 pmol g(-1) globin . This compares to a German EKA value ( exposure equivalent for carcinogenic substances ) for a daily 8-h-exposure to 1 ppm EO of 90 \u03bcg L(-1) blood ( pmol g(-1) globin ) . The adduct levels dropped in accordance with the expected zero-order kinetics for a single exposure . After the five-month observation interval , the HEV concentrations in blood reflected the individual background from tobacco smoking . The results of this study show that even a short exposure to ethylene oxide may result in a significant rise in haemoglobin adduct levels . Although protein adducts and their occupational-medical assessment values are considered for long-term exposure surveillance , they can also be used for monitoring accidental exposures . In these cases , the calculation of daily ' ppm-equivalents ' may provide a means for a comparison with the existing assessment values .
|
[
0,
0,
0,
0,
0,
0,
0,
0,
0,
0
] |
22728792
|
We investigated the effectiveness of continuous hyperthermic peritoneal perfusion ( CHPP ) for the peritoneal dissemination of gastric cancer . A total 124 patients with advanced gastric cancer were enrolled in this study . Prophylactic CHPP ( P-CHPP ) was performed in 45 patients who had macroscopic serosal invasion without peritoneal dissemination , and 79 patients without CHPP were a control group . Therapeutic CHPP ( T-CHPP ) was performed in 21 patients with peritoneal dissemination , and 52 patients without CHPP were a control group . There was no significant difference in 5 year survival between patients treated and not treated with P-CHPP . Univariate analysis showed that location of tumor , tumor diameter , and lymph node metastasis influenced prognosis , but there was no prognostic factor in the Cox proportional regression hazard model . There was no significant difference in 5-year survival between patients treated and not treated with T-CHPP . Univariate analysis showed that degree of peritoneal dissemination and adjuvant chemotherapy influenced prognosis , and the Cox proportional regression hazard model showed that the macroscopic types and degree of peritoneal dissemination affected prognosis . In the patients with CHPP , the incidences of respiratory failure and renal failure were each statistically greater than in the patients undergoing CHPP .
|
[
1,
0,
0,
0,
0,
0,
0,
0,
0,
0
] |
12484029
|
Filamin-A cross-links actin filaments into dynamic orthogonal networks , and interacts with an array of proteins of diverse cellular functions . Because several filamin-A interaction partners are implicated in signaling of cell mobility regulation , we tested the hypothesis that filamin-A plays a role in cancer metastasis . Using four pairs of filamin-A proficient and deficient isogenic cell lines , we found that filamin-A deficiency in cancer cells significantly reduces their migration and invasion . Using a xenograft tumor model with subcutaneous and intracardiac injections of tumor cells , we found that the filamin-A deficiency causes significant reduction of lung , splenic and systemic metastasis in nude mice . We evaluated the expression of filamin-A in breast cancer tissues by immunohistochemical staining , and found that low levels of filamin-A expression in cancer cells of the tumor tissues are associated with a better distant metastasis-free survival than those with normal levels of filamin-A . These data not only validate filamin-A as a prognostic marker for cancer metastasis , but also suggest that inhibition of filamin-A in cancer cells may reduce metastasis and that filamin-A can be used as a therapeutic target for filamin-A positive cancer .
|
[
1,
0,
0,
0,
0,
0,
0,
0,
0,
0
] |
23289018
|
Metformin , one of the most widely used antidiabetic drugs , has recently been associated with potential antitumorigenic effects . In this study , we evaluated the possible cytotoxic impact of combined low doses of metformin and ionizing radiation ( IR ) on 2human hepatoma cell lines . The cytotoxic effect of metformin combined with IR was subsequently determined by clonogenic survival and cell cycle assays , assessment of mitochondrial complexI and lactate dehydrogenase ( LDH ) activity , measurement of cellular adenosine triphosphate ( ATP ) levels , comet assay and analyses of the formation and disappearance of phosphorylated histone H2AX ( γ-H2AX ) protein . The combination of metformin and IR caused a much stronger cytotoxicity than the treatment with metformin or IR alone , leading to an decrease in cell viability and increase in the accumulation of cells in the G2/M phase of the cell cycle in the 2hepatoma cell lines . In addition , a reduction in mitochondrial complexI activity ( and a significant increase in LDH activity , as well as lactate production were observed in the cells exposed to metformin . Interestingly , a severe depletion in ATP , increased olive tail moment and the delayed disappearance of γ-H2AX expression were detected in the hepatoma cells treated by metformin plus IR . These findings show that the combination of a low concentration of metformin and IR results in the considerable enhancement of cytotoxic effects in human hepatoma cell lines , leading to decreased DNA repair by reducing ATP production . The data provided in this study may elucidate the remarkable efficiency of this combination treatment and suggest that metformin may be used as a potential adjunct to the radiotherapy of hepatocellular carcinoma .
|
[
0,
0,
0,
0,
0,
0,
0,
0,
0,
0
] |
22843031
|
ABSTRACT : BACKGROUND : Chemokine receptor CXCR4 , together with its ligand CXCL12 , plays critical roles in cancer progression , including growth , metastasis and angiogenesis . Ewing sarcoma is a sarcoma with poor prognosis despite current therapies , particularly for patients with advanced-stage disease . Lungs and bone ( marrow ) , organs of predilection for ( primary/metastatic ) Ewing sarcoma , represent predominant CXCL12 sources . METHODS : To gain insight into the role of the CXCR4-CXCL12 axis in Ewing sarcoma , CXCR4 , CXCL12 and hypoxia-inducible factor-1alpha protein expression was studied in therapy-naive and metastatic tumors by immunohistochemistry . CXCR4 function was assessed in vitro , by flow cytometry and proliferation/ cell viability assays , in the presence of recombinant CXCL12 and/or CXCR4-antagonist AMD3100 or under hypoxic conditions . RESULTS : Whereas CXCR4 was predominantly expressed by tumor cells , CXCL12 was observed in both tumor and stromal areas . Survival analysis revealed an ( expression level-dependent ) negative impact of CXCR4 expression ( p < 0.04 ) . A role for the CXCR4-CXCL12 axis in Ewing sarcoma growth was suggested by our observations that i ) CXCR4 expression correlated positively with tumor volume at diagnosis ( p = 0.013 ) , ii ) CXCL12 was present within the microenvironment of virtually all cases , iii ) CXCL12 induced proliferation of CXCR4-positive Ewing sarcoma cell lines , which could be abrogated by AMD3100 . CXCR4 expression was not correlated with occurrence of metastatic disease . Also , therapy-naive tumors demonstrated higher CXCR4 expression as compared to metastases ( p = 0.027 ) . Evaluation of in vivo hypoxia-inducible factor-1alpha expression and culture of cells under hypoxic conditions revealed no role for hypoxia in CXCR4 expression . CONCLUSIONS : Together , our results imply a crucial role for the CXCR4-CXCL12 axis in auto- and/or paracrine growth stimulation . Integration of CXCR4-targeting strategies into first- and/or second-line treatment regimens may represent a promising treatment option for Ewing sarcoma .
|
[
1,
0,
0,
0,
0,
0,
0,
0,
0,
0
] |
23249693
|
The development and progression of esophageal cancer is associated with multiple alterations in the genome , including loss of the tumor suppressor phosphatase and tensin homolog deleted from the chromosome 10 ( PTEN ) gene . The purpose of this study was to determine the effects of adenovirus-mediated MMAC/PTEN expression on the growth and survival of human esophageal cancer cells in vitro and in vivo . We found that compared to control cells , overexpression of PTEN significantly suppressed growth and induced apoptosis in esophageal cancer cell lines Eca-109 and TE-1 via downregulation of Bcl-2 expression and changes in cell-cycle progression . Adenovirus PTEN also inhibited the growth of subcutaneous tumor xenografts by significantly reducing tumor size in vivo . Thus our results confirm the proposed functional role of MMAC/PTEN as a regulator of esophageal cancer progression in vivo and in vitro . PTEN might be an important biological marker and potential therapeutic target in the treatment of human esophageal cancer .
|
[
0,
0,
0,
0,
1,
0,
0,
1,
1,
0
] |
20378992
|
Inflammation is a major risk factor for carcinogenesis in patients affected by chronic colitis , yet the molecular mechanisms underlying the progression from chronic inflammation to cancer are not completely understood . Activation of the Toll-like receptor 4 ( TLR4)-NFκB signaling axis is associated with inflammation . Thus , we hypothesized that inhibition of TLR4-NFκB signaling might help in limiting inflammatory responses and inflammation-induced oncogenesis . In this work , we studied the effects of a TLR4-interacting surfactant protein A-derived ( SPA4 ) peptide on lipopolysaccharide ( LPS)-induced TLR4-NFκB signaling and cancer progression . We first characterized this peptide for its ability to bind the TLR4 ligand-LPS and for physico-chemical characteristics . Inflammation was induced by challenging the colon cancer SW480 cells with Escherichia coli LPS . Cells were then treated with varying amounts of the SPA4 peptide . Changes in the expression of TLR4 , interleukin ( IL)-1β and IL-6 , in intracellular NFκB-related signal transducers ( IKBα , p65 , phosphorylated IKBα , phosphorylated p65 , RelB , COX-2 ) as well as in the transcriptional activity of NFκB were studied by immunocytochemistry , immunoblotting and NFκB reporter assay , respectively . Simultaneously , the effects on LPS-induced cell migration and invasion were determined . We found that the SPA4 peptide does not bind to LPS . Rather , its binding to TLR4 inhibits the LPS-induced phosphorylation of p65 , production of IL-1β and IL-6 , activity of NFκB , migration and invasion of SW480 cells . In conclusion , our results suggest that the inhibition of TLR4-NFκB signaling by a TLR4-binding peptide may help for the treatment of chronic inflammation and prevention of inflammation-induced cancer in patients with colitis .
|
[
1,
0,
0,
0,
0,
0,
0,
0,
0,
1
] |
23264896
|
Tumor cells exhibit enhanced glucose consumption and lactate production even when supplied with adequate oxygen ( a phenomenon known as the Warburg effect , or aerobic glycolysis ) . Pharmacological inhibition of aerobic glycolysis represents a potential tumor-selective approach that targets the metabolic differences between normal and malignant tissues . Human breast tumor MDA-MB-231 cells were used to develop an assay system to discover natural product-based glycolysis inhibitors . The assay employed was based on hypersensitivity to glycolytic inhibition in tumor cells treated with the mitochondrial electron transport inhibitor rotenone . Under such conditions , ATP supply , and hence cell viability , depends exclusively on glycolysis . This assay system was used to evaluate 10648 plant and marine organism extracts from the U.S. National Cancer Institute's Open Repository . Bioassay-guided isolation of an active Moronobea coccinea extract yielded the new bis-geranylacylphloroglucinol derivative moronone ( 1 ) . Compound 1 exhibited enhanced antiproliferative/cytotoxic activity in the presence of rotenone-imposed metabolic stress on tumor cells . Surprisingly , mechanistic studies revealed that 1 did not inhibit glycolysis , but rather functions as a protonophore that dissipates the mitochondrial proton gradient . In the presence of rotenone , tumor cells may be hypersensitive to protonophores due to increased ATP utilization by the ATP synthase .
|
[
0,
0,
1,
0,
0,
0,
0,
0,
0,
0
] |
23245650
|
Chronic inflammation is a risk factor for the development of colon cancer , providing genotoxic insults , growth and pro-angiogenic factors that can promote tumorigenesis and tumor growth . Immunomodulatory agents can interfere with the inflammation that feeds cancer , but their impact on the transformed cell is poorly understood . The calcium/calcineurin signaling pathway , through activation of NFAT , is essential for effective immune responses , and its inhibitors cyclosporin A ( CsA ) and FK506 are used in the clinics to suppress immunity . Moreover , the kinases GSK3β and mTOR , modulated by PI-3K/Akt , can inhibit NFAT activity , suggesting a cross-talk between the calcium and growth factor signaling pathways . Both NFAT and mTOR activity have been associated with tumorigenesis . We therefore investigated the impact of calcineurin and PI-3K/mTOR inhibition in growth of human colon carcinoma cells . We show that despite the efficient inhibition of NFAT1 activity , FK506 promotes tumor growth , whereas CsA inhibits it due to a delay in cell cycle progression and induction of necroptosis . We found NFκB activation and mTORC1 activity not to be altered by CsA or FK506 . Similarly , changes to mitochondrial homeostasis were equivalent upon treatment with these drugs . We further show that , in our model , NFAT1 activation is not modulated by PI3K/mTOR . We conclude that CsA slows cell cycle progression and induces necroptosis of human carcinoma cell lines in a TGFβ- , NFAT- , NFκB- and PI3K/mTOR-independent fashion . Nevertheless , our data suggest that CsA , in addition to its anti-inflammatory capacity , may target transformed colon and esophagus carcinoma cells without affecting non-transformed cells , promoting beneficial tumoristatic effects .
|
[
0,
0,
0,
0,
0,
0,
0,
0,
1,
1
] |
22992618
|
Metabolic reprogramming of cancer cells provides energy and multiple intermediates critical for cell growth . Hypoxia in tumors represents a hostile environment that can encourage these transformations . We report that glycogen metabolism is upregulated in tumors invivo and in cancer cells invitro in response to hypoxia . Invitro , hypoxia induced an early accumulation of glycogen , followed bya gradual decline . Concordantly , glycogen synthase ( GYS1 ) showed a rapid induction , followed by a later increase of glycogen phosphorylase ( PYGL ) . PYGL depletion and the consequent glycogen accumulation led to increased reactive oxygen species ( ROS ) levels that contributed to a p53-dependent induction of senescence and markedly impaired tumorigenesis invivo . Metabolic analyses indicated that glycogen degradation by PYGL is important for the optimal function of the pentose phosphate pathway . Thus , glycogen metabolism is a key pathway induced by hypoxia , necessary for optimal glucose utilization , which represents a targetable mechanism of metabolic adaptation .
|
[
0,
0,
0,
1,
0,
0,
0,
0,
0,
1
] |
23177934
|
Aberrant expression and polymorphism of fibroblast growth factor receptor 4 ( FGFR4 ) has been linked to tumor progression and anticancer drug resistance . We describe here a novel mechanism of tumor progression by matrix degradation involving epithelial-to-mesenchymal transition in response to membrane-type 1 matrix metalloproteinase ( MT1-MMP , MMP-14 ) induction at the edge of tumors expressing the FGFR4-R388 risk variant . Both FGFR4 and MT1-MMP were upregulated in tissue biopsies from several human cancer types including breast adenocarcinomas , where they were partially coexpressed at the tumor/stroma border and tumor invasion front . The strongest overall coexpression was found in prostate carcinoma . Studies with cultured prostate carcinoma cell lines showed that the FGFR4-R388 variant , which has previously been associated with poor cancer prognosis , increased MT1-MMP-dependent collagen invasion . In this experimental model , knockdown of FGFR4-R388 or MT1-MMP by RNA interference blocked tumor cell invasion and growth in collagen . This was coupled with impaired phosphorylation of FGFR substrate 2 and Src , upregulation of E-cadherin , and suppression of cadherin-11 and N-cadherin . These in vitro results were substantiated by reduced MT1-MMP content and in vivo growth of prostate carcinoma cells after the FGFR4-R388 gene silencing . In contrast , knockdown of the alternative FGFR4-G388 allele enhanced MT1-MMP and invasive tumor cell growth in vivo and within three-dimensional collagen . These results will help to explain the reported association of the FGFR4-R388 variant with the progression and poor prognosis of certain types of tumors .
|
[
1,
0,
0,
0,
0,
0,
0,
0,
1,
0
] |
20876804
|
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