p53 protein expression in A549 cells without (A) or with (B) p53 siRNA transfection and the effect of p53 siRNA transfection on apoptosis (C) induced by various treatments.

The A549 cells were transfected with or without p53 siRNA before incubation with 25 ng/mL trichostatin A (TSA) alone or in combination with 5 µM quercetin (5Q) for 12 h or 48 h for the p53 expression assay and apoptosis assay, respectively. Values (mean ± SD) in the same group not sharing a common letter (a-c and A-C for without or with p53 siRNA, respectively) are significantly different (p<0.05). *denotes a significant different from p53-normal cells in the same treatment. (p<0.05). #denotes a significant interaction between TSA and quercetin (two-way ANOVA, p<0.05).