Determination of cell cycle phases using flow cytometry

Cells were seeded in 6-well tissue culture dishes at 1 × 10⁵ cells per well. The cells were allowed to adhere for 24 h and were then incubated with the indicated drug concentrations. Each condition was tested in triplicate wells. The cell cycle phases of the treated cells were determined by quantifying their DNA content through staining with propidium iodide staining, and the cell cycle phases were analyzed by a FACS scanner (Becton Dickinson Immunocytometry Systems, San Jose, CA, USA) and quantified by Cell Quest software (Becton Dickinson Immunocytometry Systems).