Effects of metformin on apoptosis and the expression of apoptosis-related genes of Hep-G2 cells

Objective To investigate the effect of metformin on proliferation, apoptosis of Hep-G2 cells and tumor growth in nude mice. Methods Hep-G2 cells were treated with metformin at different concentrations, and cell viability was measured by using methyl thiazol tetrazolium (MTT) method. Cell cycle and apoptosis rate were assayed by flow cytometry. The expression of apoptosis-related protein were detected by Western blotting.Nude mice were transplanted with Hep-G2 cells, and tumor growth inhibition rate was detected. Results After Hep-G2 cells were treated with 20 mmol/L metformin for 48 h, the growth cycle was arrested in G0/G1 phase, the apoptosis rate was (20.57±3.16)%, the expression of bcl-2 and bcl-xl proteins was down-regulated after metformin treatment, while the Bid protein was significantly increased, tumor size in the high-dose metformin group, cisplatin combined with metformin group were significantly reduced as compared with control group, and the inhibition rates in the high-dose metformin group, cisplatin combined with metformin group was 40.8% and 72.8% respectively. ConclusionMetformin inhibits proliferation of Hep-G2 cells, and induces apoptosis in vitro and significantly inhibits the growth of hepatocellular carcinoma in nude mice. Key words: Metformin;  Carcinoma,hepatocellular;  Apoptosis