Fig. 2: PB causes apoptosis in melanoma cells.

a A-375 and SK-MEL-5 cells were stained with annexin V and PI and analyzed by flow cytometry. b–c A-375 and SK-MEL-5 cells were treated with the indicated concentrations of PB for 24 h or with 2 μM PB at different time points. Western blotting analysis was applied to detect the expression levels of cleaved caspase-3. β-actin served as a loading control. Data are shown as the mean ± SEM of three independent experiments. *P < 0.05, **P < 0.01, #P < 0.05, ##P < 0.01 vs. the control group.