Fig. 5

Change of mRNA expression profiles in the p53 signaling pathway. a The mRNA expression profiles were generated by microarray analysis. The genes, the expression level of which increased more than 2-fold after PARP inhibition, are indicated as a black box in the p53 signaling pathway published by the KEGG database. b The mRNA expression profiles shown in (a) were confirmed by RT-PCR. Several genes downstream to Trp53 (p53) were upregulated after PARP inhibition, whereas Trp53 itself was constant regardless of the presence of the PARP inhibitors. c Changes in the levels of p53 and phosphorylated p53 by the PARP inhibitors (PJ34, DHIQ, or 3AB) were observed in NSPCs. p21 protein as well as p21 mRNA, as shown in (b), were upregulated by all of the PARP inhibitors. Cleaved fragment of caspase-3 at Asp 175 (p17), which is a marker of apoptosis, was also increased by PARP inhibition. d Quantitative mRNA analyses after the addition of PJ34, DR2313 (PARP-1-specific inhibitor), or UPF1069 (PARP-2-specific inhibitor) were performed for the genes in the p53 signaling pathway. DR2313 as well as PJ34 upregulated the genes in the p53 signaling pathway, while UPF1069 did not change the expression of these genes, except Bbc3 (PUMA). Data shown in (d) are expressed as the ratio of the mean value of the control (vehicle alone). Data represent the mean value ± SEM (n = 3). *p < 0.05 by comparison against control using one-way ANOVA followed by Tukey’s post hoc test