Role of Bcl-2 in apoptosis induced by Rapamycin on hepatocelluar carcinoma BEL-7402 Cells

OBJECTIVE:To investigate cell growth inhibition and apoptosis induced by rapamycin on human hepatocelluar carcinoma BEL-7402 cells and the role of Bcl-2 in its action mechanism. METHODS: BEL-7402 cells were given in culture medium with rapamycin in different concentrations, 5, 10, 20, 30, 40 and 50 nmol/L. Cell viability was assessed by MTT assay. Cell apoptosis was observed by Hoechst 33258 staining and flow cytometry (FCM).The Bcl-2 apoptotic related genes were assayed by Western blotting. RESULTS: Rapamycin inhibited the growth of BEL-7402 cells and induced apoptosis significantly in time-and dose-dependent manner. Marked morphological changes of apoptosis were observed by Hoechst 33258 staining after the cells were exposed to rapamycin for 48 h. Western blotting analysis demonstrated that anti-apoptotic protein Bcl-2 and Bcl-xl were downregulatd while pro-apoptotic protein bax was upregulated remarkably in a time dependent manner when apoptosis ocurred. CONCLUSION: Rapamycin has significant antiproliferation effect by induction of apoptosis with downregulation of anti-apoptotic protein Bcl-2 , Bcl-xl and upregulation of pro-apoptotic protein bax.