Tumor growth effects of rapamycin on human biliary tract cancer cells

Background: Liver transplantation is an important treatment option for patients with liver-originated tumors including biliary tract carcinomas (BTCs). Post-transplant tumor recurrence remains a limiting factor for long-term survival. The mammalian target of rapamycin-targeting immunosuppressive drug rapamycin could be helpful in lowering BTC recurrence rates. Therein, we investigated the antiproliferative effect of rapamycin on BTC cells and compared it with standard immunosuppressants. Methods: We investigated two human BTC cell lines. We performed cell cycle and proliferation analyses after treatment with different doses of rapamycin and the standard immunosuppressants, cyclosporine A and tacrolimus. Results: Rapamycin inhibited the growth of two BTC cell lines in vitro. By contrast, an increase in cell growth was observed among the cells treated with the standard immunosuppressants. Conclusions: These results support the hypothesis that rapamycin inhibits BTC cell proliferation and thus might be the preferred immunosuppressant for patients after a liver transplantation because of BTC.