Evaluating Parp1 domains as gossypol targets

Pleiotropic role of PARP1: an overview

Poly (ADP-ribose) polymerase 1 (PARP1) protein is encoded by the PARP1 gene located on chromosome 1 (1q42.12) in human cells. It plays a crucial role in post-translational modification by adding poly (ADP-ribose) (PAR) groups to various proteins and PARP1 itself by utilizing nicotinamide adenine dinucleotide (NAD +) as a substrate. Since the discovery of PARP1, its role in DNA repair and cell death has been its identity. This is evident from an overwhelmingly high number of scientific reports in this regard. However, PARP1 also plays critical roles in inflammation, metabolism, tumor development and progression, chromatin modification and transcription, mRNA stability, and alternative splicing. In the present study, we attempted to compile all the scattered scientific information about this molecule, including the structure and multifunctional role of PARP1 in cancer and non-cancer diseases, along with PARP1 inhibitors (PARPis). Furthermore, for the first time, we have classified PARP1-mediated cell death for ease of understanding its role in cell death pathways.

Computational investigation of FDA approved drugs as selective PARP-1 inhibitors by targeting BRCT domain for cancer therapy

Poly(ADP-ribose) polymerase-1 is a promising target for the treatment of cancer due to its involvement in base excision repair pathways for repairing DNA single-strand breaks. However, available PARP-1 inhibitors target a highly conserved PARPs catalytic domain, which causes toxicity due to the off-target activity. Therefore, the present study was hypothesized to identify selective inhibitors by targeting specific protein-protein interacting (PPI) PARP-1 BRCT domain. Moreover, PPI hotspot residues (Gly399, Lys400, Leu401, Lys441 & Lys442) and a druggable pocket was detected to screen small molecule inhibitors. Hence, two FDA approved drug molecules (levoleucovorin and balsalazide) were recognized to fit in the druggable pocket. Since they are already under investigation for anti-cancer activity, thus could be further explored in PARP-1 sensitive cancer cells to expand their selectivity and develop as effective anti-cancer agents. Besides, the study also provides detailed structural insight of PARP-1 and XRCC1 complex through their BRCT domains.