Fig. 3
ZnCl2 induces p53/DNA binding and transactivation activities in the presence of low-dose ADR. a HCT116 (left panel) and RKO cells (right panel) (4x106) were plated in 150 mm dish and the day after treated with ADR (0.1-1 μg/ml) and ZnCl2 (100 μM) for 16 h before being assayed for ChIP analysis with anti-p53 antibody. PCR analyses were performed on the immunoprecipitated DNA using primers specific for p53 target genes. A sample representing linear amplification of the total chromatin (Input) was included as control. Additional controls included immunoprecipitation performed with nonspecific immunoglobulins (IP: IgG). One representative experiment, out of two independent experiments generating similar results, is shown here. b HCT116 and RKO cells were treated with ADR (0.1-0.2-0.5-1 μg/ml) in the presence or absence of ZnCl2 (100 μM) for 16 h before total mRNAs were reverse transcribed for analysis of p53 apoptotic target genes (Noxa and Puma) expression, using RT-PCR. 28S was used as a control for efficiency of RNA extraction and transcription. One representative experiment, out of two independent experiments with similar results, is shown here. c Densitometric analysis of gene expression as shown in (b) in HCT116 (left panel) and RKO (right panel) cells was plotted as expression ratio to 28S. The data represent the mean of two independent experiments ± S.D. Paired student’s t test was used for the statistical analysis of the normalized gene expression (Gene/28S ratios) at different ADR doses, with or without ZnCl2 (*: P < 0.01)