PARP1 and Hereditary breast cancer: To evaluate whether nutlin-3a could serve as a PARP suppressor against BRCA1-associated hereditary breast cancer, we examined the effects of nutlin-3a in MCF-7 cells expressing shRNA against BRCA1 (MCF-7/shBRCA1) or GFP (MCF-7/shGFP), used as a negative control.