  Through the last decade, cold atmospheric plasma (CAP) has emerged as an
innovative therapeutic option for cancer treatment. Recently, we have set up a
potentially safe atmospheric pressure plasma jet device that displays
antitumoral properties in a preclinical model of cholangiocarcinoma (CCA), a
rare and very aggressive cancer emerging from the biliary tree with few
efficient treatments. In the present study, we aimed at deciphering the
molecular mechanisms underlying the antitumor effects of CAP towards CCA both
in an in vivo and in vitro context. In vivo, using subcutaneous xenografts into
immunocompromised mice, CAP treatment of CCA induced DNA lesions and tumor cell
apoptosis, as evaluated by 8-oxoguanine and cleaved caspase-3
immunohistochemistry, respectively. Analysis of the tumor microenvironment
showed changes in markers related to macrophage polarization. In vitro,
incubation of CCA cells with CAP-treated culture media (i.e. plasma-activated
media, PAM) led to a dose response decrease in cell survival. At molecular
level, CAP treatment induced double-strand DNA breaks, followed by an increased
phosphorylation and activation of the cell cycle master regulators CHK1 and
p53, leading to cell cycle arrest and cell death by apoptosis. In conclusion,
CAP is a novel therapeutic option to consider for CCA in the future.
