PARG Inhibitors and Functional PARG Inhibition Models.

Poly(ADP-ribose) polymerases (PARPs) family proteins catalyze poly(ADP-ribosylation) (PARylation) by conjugating ADP-ribose residues repeatedly on amino acid residues using nicotinamide adenine dinucleotide as a substrate. The inhibitors of PARP widely block DNA repair processes and are currently examined in clinical trials of cancer therapy. Poly(ADP-ribose) glycohydrolase (PARG) is the main nuclear enzyme, which digests poly(ADP-ribose) into ADP-ribose. PARG inhibitor could also be considered as a chemotherapeutic agent for cancer, because of its involvement in DNA repair. Various PARG inhibitors with IC50 value of micromolar to submicromolar range have been reported. However, for most of these chemicals, the specificity of inhibition has not been fully evaluated. PARG functional inhibition models in various organisms have been developed. Here, inducible PARG knockdown system was developed in HeLa cells and the cell line will be useful for identifying the synthetic lethal genes or affecting genes for PARG inhibitor treatment and also for functional elucidation of PARP superfamily molecules.