Fig. 6.

DDR pathway [[162], [163], [164]]: The DNA damage and response pathway: The figure depicts the causative agents and plausible DNA damage repair pathways. Depending on the type of insult, there are different types of DNA damage including mismatched nucleotide, damaged bases, bulk adduct binding, single strand and double strand break. This figure also describes the outcome of the different DNA damage repair pathway leading to cell cycle arrest, senescence, and apoptosis. PARP: Poly (ADP-ribose) polymerase (PARP); PARG: Poly (ADP-ribose) glycohydrolase; ARH3: ADP-ribosylhydrolase 3; NAD: Nicotinamide adenine dinucleotide; MRN: Mre11-Rad50-Nbs1; H2AX: H2A histone family member X; ATM: Ataxia Telangiectasia mutated; ATR: Ataxia Telangiectasia and Rad3-related; CHK1, CHK2: Checkpoint kinase 1 and 2; CDK: Cyclin-dependent kinases.