Effect of metformin on the proliferation and apoptosis of the renal cancer cell line 786-O and the underlying mechanisms.

Purpose: To investigate the effects of metformin (Met) on the proliferation and apoptosis of a renal carcinoma cell line and study the underlying mechanisms. Methods: Renal cell carcinoma (RCC) line 786-O was cultured with media containing different concentrations of Met. The proliferation and apoptosis of 786-O cells were detected by the MTT method and flow cytometry, respectively. The invasion of 786-O cells was detected by scratch test, and the expression of pro-apoptotic proteins was determined by Western blot assay. Results: The proliferation rates of 786-O cells with Met concentrations of 10, 15, and 20 mM were decreased by 62.8, 61.7, and 65.1%, respectively, with no significant difference among these concentrations (p>0.05). Twenty-four hrs after the scratch assay, the mean migration index in the control group and Met treatment group was 51.6% +/- 5.9 and 28.1% +/- 4.3, and that after 48 hrs was 92.2% +/- 6.4 and 68.0% +/- 4.9, respectively (p<0.05). At low serum concentration, the percentage of apoptotic cells in the Met treatment group (17.6%) was significantly higher (p<0.05) than that. in the control group (5.2%). Met (10 mM) treatment significantly increased the expression of Caspase-3 and Bax proteins in 786-O cells (p<0.05). Conclusions: Metformin may be a potential drug of choice in the treatment of metastatic RCC.