Effect of SCH722984, vemurafenib or the combination on cell cycle progression and apoptosis in BRAF-mutant melanoma cell lines. Two sensitive cell lines (M238 and M792) and two resistant cell lines (M233 and M299) were exposed to DMSO as vehicle control (Unst, control unstained: Control, control stained), 1 μM vemurafenib (Vem), SCH722984 (ERKi), the combination (V + E) or 1 μM staurosporine for 48 hours. A. Cell cycle progression was tested by DAPI staining solution and induced apoptosis by cleaved PARP (PARP-Ax700). Figures are representative of triplicate experiments. B. Quantitative analysis of the cell cycle progression by DAPI staining using flow cytometry shows the percentage of cells in sub-G0 (blue), G0/G1 (red), S phase (yellow), or G2/M (green). Numbers on the bar graph represent percentage of cells in G0/G1. Columns represent mean values of three independent experiments (n = 3); bars, SEM. C. Apoptosis in response to MAPK inhibitors. Percentage of apoptotic cells positive for cleaved PARP (PARP-Ax700) in this four melanoma cell lines. Columns represent mean values of three independent experiments (n = 3); bars, SEM; *, P < 0.05.