Fig. 4.

PARP-1 inhibition abrogates nuclear accumulation and p53 PARylation. Differentiated SH-SY5Y cells were pre-treated with PARP-1 inhibitor ABT-888 (10 µM) for 1 h following which the cells were treated with increasing concentrations of cocaine for 24 h. Post-treatment cells were harvested, cytoplasmic and nuclear extract were isolated and further subjected to immunoblot analyses for p53 expression. ABT-888 abrogates cocaine-induced p53 nuclear accumulation. A, C Representative blots showing the effect of ABT-888 pretreatment followed by cocaine treatment on nuclear and cytoplasmic p53 expression, respectively. Densitometry analyses of nuclear p53 (B) and cytoplasmic p53 (D) from (n = 3) independent experiments. One-way ANOVA, multiple comparison analysis with Tukey’s test; *p < 0.05, **p < 0.01 for the comparison of cytoplasmic p53 levels between saline (0 µM) and treated groups. ABT-888 abrogates PARylation of p53. E Representative western blot showing effect of cocaine on PARylated p53 in presence of DMSO (vehicle) and ABT-888 pre-treated cells with respective controls. F Densitometry analysis for effect of PARP-1 inhibitor (ABT-888) on levels of PARylated nuclear p53. Two-way ANOVA, multi way analysis with Tukey’s test; *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001 for the comparison of relative PARylated p53 expression normalized to IgG Light chain (Lc) across varying treatments of cocaine as well as, in cocaine concentrations between the experimental groups