Fig.1 Metformin inhibits the proliferation of cells in a dose-dependent manner.

(A) Ishikawa cells and HEC IB cells were treated with metformin for 48 h.Cell proliferation was measured using the thymidine incorporation assays. Results are presented as means ± standard errors of the mean. Asterisks indicate significant differences compared with metformin-free controls ( P＜ 0.05, Mann-Whitney U-test). From Mitsuhashi et al., modified with permission^［21］.
(B) Flow cytometry analysis of Ishikawa cells after 24 h treatment with 5 or 10 mM metformin. The cells in the G1 phase of the cell cycle is indicated. After the addition of metformin, G1 cells increased by 18.6% in those treated with 5 mM metformin and 23% in those treated with 10 mM metformin compared to 16.8% in the control.