Cell cycle analysis by flow cytometry

MDA-MB-453, HCC1428 and MCF-7 cells were treated with different compounds as indicated and cells were collected, washed twice with cold PBS, fixed with 70% ethanol overnight at 4 °C and stained with PI (50 mg/ml, Sigma) plus 0.2 mg/ml DNase-free RNase A (Qiagen) for 30 min at rt. Cell cycle analysis was performed by the University of Michigan Flow Cytometry Core.