Metformin increased cell death and caspase activity in MCF-7 cells.

<p>(<b>A–C</b>) MCF-7 cells exposed to 10 mM metformin for 48 and 72 hours were analyzed with flow cytometry. Results were expressed as percentage of PI positive cells. (<b>D–F</b>) Apoptosis was determined by measuring active caspase-3 and -7 positive MCF-7 cells after 48 and 72 hours of treatment using flow cytometry. Results were expressed as mean fluorescence arbitrary units (AU). (<b>G–H</b>) MCF-7 cells were treated with 10 mM metformin for 24 and 48 hours. Apoptosis was determined by Annexin V propidium iodide staining and measured by flow cytometry. Apoptotic cells were measured as percentage of AV⁺/PI^- stained cells. ** p<0.001 vs. control, *** p<0.0001 vs. control.