Effect of leptin on proliferation and apoptosis of cholangiocarcinoma QBC939 cells 

Objective To determine whether leptin can exert anti-proliferative and pro-apoptotic effects on human cholangiocarcinoma cells and to investigate the underlying molecular mechanisms.Methods Human cholangiocarcinoma QBC939 cells were cultured and treated with different concentrations of leptin.Changes in the proliferation rate were measured by the MTT assay.Changes in cell cycle and in the apoptosis incidence rate were detected by flow cytometry.Changes in cyclin D1, bax and bcl-2 gene expression were detected by measuring mRNA levels by real-time quantitative reverse transcription-polymerase chain reaction (qPCR) .Changes in caspase-3 protease activity were detected by fluorometric assay.Results Leptin treatment significantly increased the proliferation rate of QBC939 cells in a dose-and time-dependent manner.Compared to untreated QBC939 cells, leptin treatment led to significantly more G0/G1 to S phase transition and significantly lower apoptosis rate.In addition, leptin-treated QBC939 cells showed enhanced mRNA expression of cyclin D1 and bcl-2, but decreased mRNA expression of bax.The leptin treatment also led to decreased caspase-3 activity.Conclusion Leptin promotes S to G0/G1 phase transition and proliferation, but inhibits apoptosis, of human cholangiocarcinoma cells in vitro.