Effect of vitamin C on the expression of apoptosis-associated proteins in A375 cells. (A) Whole cell extracts and mitochondria lysis were prepared for cells treated with vitamin C for 6 h, and the expression levels of mitochondrial-cytochrome c, Bax, Bcl-2, caspase-3 and caspase-9 were determined by western blotting. (B) Relative protein expression levels of mitochondrial-cytochrome c, Bax, Bcl-2, caspase-3 and caspase-9 are shown. β-actin was used as the internal control. *P<0.05, **P<0.01 vs. Ctrl. Ctrl, control.