Fig. 1

A Cell viabilities of TCam-2 and NTERA-2 cells determined by MTT assay after treatment with different concentrations of metformin (1 mM, 5 mM, 10 mM, 15 mM and 20 mM) for 24 h, 48 h and 72 h. B Flow cytometry analysis showed the cellular apoptosis of TCam-2 and NTERA-2 cells treated with 10 and 20 mM metformin at 72 h, and the average percentages of apoptotic cells were determined. C Flow cytometry showed that the TCam-2 and NTERA-2 cell cycle was blocked in G1 phase after treatment with metformin at 5–20 mM for 72 h. D TCam-2 and NTERA-2 cells were treated with metformin for 24, 48 and 72 h. Student’s t-test (two-tailed, equal variance) was used to calculate P values: *P < 0.05, **P < 0.01, ***P < 0.001 and ****P < 0.0001