Study on inhibitory effect of metformin in bladder cancer and its mechanism

Objective: To investigate the inhibitory effect of metformin on bladder cancer cell and its mechanism. Methods: In this study, metformin with different concentrations (0, 2, 5, 10, 20 mM) was used for the intervention on bladder cancer cell lines 5637 and T24 in vitro. Its influence on the growth and proliferation of cells was detected by MTT assay; the impact on cell colony formation was quantitatively analyzed by Quantity One software; the influence on cell apoptosis was examined by Annexin V/double staining assay. Bladder cancer cell xenograft was constructed in nude mice, and the effect of metformin on the volume and weight of xenograft was observed. Results: After 48 hours’ intervention by metformin with different concentration, by comparing with control group, the cell activity of 5637 cells and T24 cells was obviously reduced, and a significant reduction was observed in colony formation of bladder cancer cells after the intervention of metformin. Metformiin with high concentration had no significant induction on the apoptosis of 5637 cells and T24 cells; compared with the control group, the difference was no statistically significant. In vivo experiments showed that intraperitoneal injection of metformin could obviously inhibit the growth of tumor xenograft. Conclusion: metformin can significantly inhibit the ability of proliferation and colony formation of bladder cancer cells in vitro, this inhibition may not be achieved by inducing apoptosis of bladder cancer cells.