... mutation carriers. Why are BRCA1- and BRCA2-deficient cells extremely sensitive to PARP-1 inhibition? The products of the genes, BRCA1, BRCA2 and PARP-1, are nuclear proteins and are critical components ... BRCA2-deficient pancreatic cancer cells? Because PARP-1-null mice are viable and healthy [32], and inhibitors that are specific for PARP-1 are relatively non-toxic and do not directly damage DNA, PARP-1 ... profoundly reduced colony formation (up to 100 fold) of MCF-7 and MDA-MB-231 cells when BRCA2 was depleted by RNAi compared with untreated control cells [24]. Studying Int. J. Med. Sci. 2006, 3 ...