Figure 3
Effects of PPD on cell cycle progression of cancer cells were analyzed using flow cytometry. (A) K562 cells were exposed to PPD at 0, 12.5, 25 and 50 μM for 48 hr. Then, they were fixed with ethanol, stained with propidium iodide and analyzed using flow cytometry. (B) K562 cells were exposed to PPD at 0, 12.5 and 25 μM for 24 hr, then expression levels of cell cycle regulators and pro-apoptotic proteins were determined with Western blotting using anti-cdk2, -cdk4, -cdk6, -cyclinA and -cyclinB1 antibodies, -PARP, -Bcl-2, and -caspase-9 antibodies. (C) Relative percentages of cells were calculated at sub-G1, G1, S and G2/M phases. (D) All experiments were repeated three times with similar results, so the means ± standard deviations of band intensities were calculated in our Western blot analyses for cell cycle and apoptosis components. *, p < 0.05; **, p < 0.01; ***, p < 0.001 for control (vehicle) are considered as significant.