(L) SMAD3, Phospho-SMAD3 Ser423/425 and BIRC3 expression levels in melanoma cell lines. Four subtypes of melanoma cells (U, undifferentiated; NC, neural crest-like; T, transitory; M, melanocytic) have been compared. 501Mel and M249 cells are melanocytic cells in contrast to dedifferentiated BRAFi-resistant cells (R). Three couples of melanoma cell lines (Sensitive (S) and (R)) have been used to illustrate the SMAD3 and BIRC3 increases in BRAFi-resistant cell lines. HEK293 cells are used as control (kidney). HSC70 serves as loading control for western-blot experiments. Each antibody has been evaluated on individual membrane (explaining the three HSC70, loading controls). 