NAC induces p53 and reduces p63 protein expression through activation of PPARα. A-B, Cellular protein was isolated from A549 cells cultured with NAC (5 mM) for 24 h, followed by Western blot analysis with antibodies against p53, p50 and p65 proteins. C, A549 cells were treated with GW6470 (20 μM) for 2 h before exposure of the cells to NAC (5 mM) for an additional 24 h. Afterwards, Western blot analysis was performed using polyclonal antibodies against p53 and p65 protein. The bar graphs represent the mean ± SD of p53 or p65/GAPDH of at least three independent experiments. *indicates significance as compared with controls (CTR). **indicates significance of combination treatment as compared with NAC alone (p < 0.05).