Antiproliferative effect of all-trans-retinoic acid in cholangiocarcinoma

Cholangiocarcinoma (CCA) is an aggressive and potentially fatal bile duct cancer. This cancer responds poorly to current radiotherapy and chemotherapy, consequently, searching for novel therapeutic options of CCA is an urgent need. All-trans-retinoic acid (atRA), vitamin A derivative, is well-known to regulate cell behavior and to play key roles in determination of cell fate. Clinically, atRA is considered as a potential anti-tumor agent against human hematopoietic cancers. Up to now, little is known about the effect of atRA on treating human CCA. We aimed to investigate the potential of atRA in suppressing the proliferation of human CCA cells. In vitro experiments including sulforhodamine B (SRB) and colony-forming assays were performed in KKU-100 CCA cells. The result showed that, in a dose-dependent manner, atRA significantly reduced cell viability of cholangiocarcinoma cells. The long-term reproductive survival of CCA cells were also suppressed by atRA treatment. Our data demonstrate the anti-proliferative effect of atRA on CCA cells and suggest that atRA may be a potential therapeutic agent for the treatment of CCA. Therefore further studies investigating to understand the molecular mechanisms underlying its effects and in vivo anticancer benefit of atRA for the treatment of CCA are warranted.