Low concentrations of metformin induced cell cycle arrest but not apoptosis in CD133⁺ pancreatic cancer cells.

<p>A, Effect of low concentrations of metformin on apoptosis in pancreatic cancer. AsPC-1 and SW1990 cells were incubated with 0.2 mM or 0.1 mM metformin, respectively, for 72 h and the proportions of apoptotic cells were determined by flow cytometry. No significant differences were observed between the treated cells and controls. B, Effect of low concentrations of metformin on the cell cycle in pancreatic cancer. AsPC-1 and SW1990 cells were incubated with 0.2 mM or 0.1 mM metformin, respectively, for 72 h and the proportions of cells in each stage of the cell cycle were determined by flow cytometry. A decrease of total S phase cells and an increase of G0/G1 phase suggest G1/S arrest in CD133⁺ cells. Error bars represent the standard deviation. ^*<i>P</i><0.05.