Fig. 5. The effect of p53 knockdown on cell cycle in LNCaP and 22Rv1 cells. (A) Immunoblotting for p53 and glyceraldehyde 3-phosphate dehydrogenase (GAPDH) using lysates from LNCaP cells transfected with control siRNA or p53-targeted siRNA and treated with dimethyl sulfoxide (DMSO) or 40 µM piceatannol (PIC) for 24 hours. The numbers on top of the band indicate fold change in the protein level compared to control siRNA-transfected cells treated with DMSO. GAPDH was used for normalization. The experiments were repeated twice with consistent results. Representative data from one such experiment is shown. (B) Quantification of cell distribution of LNCaP cells transfected with control siRNA or p53-targeted siRNA and treated with DMSO or 40 µM PIC for 24 hours. The results are expressed as mean ± SD (n = 3). aStatistically significant as P < 0.05 compared with DMSO-treated control within group; bStatistically significant as P < 0.05 compared with the same treatment between groups by one-way analysis of variance followed by Bonferroni’s multiple test. The experiments were repeated twice with consistent results. Representative data from one such experiment is shown. (C) Immunoblotting for p53 and GAPDH using lysates from 22Rv1 cells transfected with control siRNA or p53-targeted siRNA and treated with DMSO or 40 µM PIC for 24 hours. The numbers on top of the band indicate fold change in protein level compared to control siRNA-transfected cells treated with DMSO. GAPDH was used for normalization. The experiments were repeated twice with consistent results. Representative data from one such experiment is shown. (D) Quantification of cell distribution of 22Rv1 cells transfected with control siRNA or p53-targeted siRNA and treated with DMSO or 40 µM PIC for 24 hours. The results are expressed as mean ± SD (n = 3). Representative data from one such experiment is shown.