Figure 3. Potent flavonol F20 induces apoptosis through activation of the extrinsic and intrinsic apoptotic pathway caspases in melanoma and non-melanoma cancer cells.

The blots show the effect of F20 at IC₅₀ and 2×IC₅₀ concentrations on the protein expression levels of markers of apoptosis, including pro- and-cleaved caspase−3, −7 and −8, components of the intrinsic apoptosis pathway, after 48-h treatment, comparing with untreated controls. A375 and A431 cells were incubated in the absence or presence of F20 (0, IC₅₀, 2×IC₅₀; 48 h), and whole-cell lysates were subjected to SDS-polyacrylamide gel electrophoresis. The Western blot data shown are representative immunoblots from three independent experiments with similar results. Equal protein loading was confirmed by re-probing for β-actin or GAPDH as loading control, and the actual protein levels were normalized to the loading control to obtain % Expression values shown on the bar graphs (mean ± SD of relative quantitative density values are plotted). The data are expressed as the percentage to which derivatives F20 suppressed or induced the protein expression levels of pro- and-cleaved caspases in A375 and A431 cells as compared with controls. Statistical significance was assessed using one-way ANOVA and Dunn’s multiple comparison tests, and p < 0.05 (*) was considered significant.