Figure 4

Metformin and tamoxifen promote the apoptosis of MCF-7 and ZR-75-1 cells. MCF-7 and ZR-75-1 cells were treated with 5 or 10 μM Tam, 5 mM Met, or 5 or 10 μM Tam + 5 mM Met. After 4 days, apoptosis was measured. (A and C) Annexin/propidium iodide staining was used to examine apoptosis of the cells. (B and D) Histograms represent the quantification of apoptotic cells. *P < 0.05 for the 5 μM Tam group vs. the 5 μM Tam + 5 mM Met group; ^# P < 0.05 for the 10 μM Tam group vs. the 10 μM Tam + 5 mM Met group. (E and F) MCF-7 and ZR-75-1 cells were treated with 5 mM Met, 10 μM Tam or 10 μM Tam + 5 mM Met for 4 days. Protein was extracted and subjected to western blot. The expression of the target proteins was normalized to β-actin.