Poly(ADP-Ribose) Polymerase-1 Inhibitors Drug Discovery, Design, and Development as Anticancer Agents from Past to Present: A Mini-Review

Cancer treatments are known for their life-threatening toxicities attributed to their low selectivity; hence, new therapeutic approaches are being developed as alternatives. Among those approaches is the DNA repair mechanism, where its inhibition results selectively in the death of cancerous cells. Poly(ADP-Ribose) Polymerase (PARP) is one of the enzymes involved in the repair of damaged DNA. The inhibition of PARP shows to be a promising approach for effective targeted treatment of cancer, especially in tumours with pre-existing Homologous-Repair (HR) defects (i.e., BRCA). Nicotinamide, which is one of the PARP catalytic products, was the first identified PARP inhibitor (PARPi). The first FDA-approved PARPi was Olaparib in 2014 for the treatment of BRCA mutated advanced ovarian cancer. Several clinical trials have been conducted to further improve PARPi. However, there are some concerns related to drug resistance, PARPi sensitive-tumour identification, and toxic accumulation of PARPi. This report will review the uses of PARPi, drug design and development of PARPi from past to present, current issues, and prospective plans.