Abstract 1214 Functional Implications of PARP1 Mutations in Cancer: Toward Targeted Therapies for Genetic Diseases

Ataxia-telangiectasia (A-T) is a neurological disorder characterized by early-onset cerebellar neurodegeneration. It arises from the functional loss of the ATM kinase, a key component in the DNA damage response pathway. Studies have demonstrated the association between A-T and the accumulation of misfolded and aggregated proteins, particularly under conditions of oxidative stress. Interestingly, hallmark neurodegenerative diseases such as Alzheimer's and Parkinson's also exhibit similar characteristics. Poly(ADP-ribose) polymerase 1 (PARP1), through its pivotal role in DNA repair and response to oxidative stress, emerges as a potential contributor to the pathogenesis of these disorders. While PARP1 activity can activate the defense mechanism in cells against DNA damage and oxidative stress, excessive PARP1 activation has been shown to promote protein aggregation and cellular dysfunction, demonstrating the intricate balance required for PARP1-mediated processes. Notably, PARP1 has garnered significant attention in cancer therapy, as PARP inhibitors have shown clinical efficacy in homologous recombination (HR) deficient cancers, including BRCA-mutated breast and ovarian cancers. However, the regulatory mechanisms of PARP1's enzymatic site requires further investigation. The objective of this study is to explore the impact and the biochemical activity of PARP1 mutations found in patients with cancer. To achieve this, site-directed mutagenesis was utilized to specifically target amino acids within PARP1 and generate mutations that have been identified in patients with diverse types of cancer. Expression and purification conditions of the recombinant PARP1 mutant proteins are being optimized, and in vitro PARylation assays will be conducted to examine how the PARP1 mutation affects its enzymatic activity. Six different mutations have been successfully generated thus far and are currently in the process of being optimized for expression. This understanding holds the potential to enable precise modulation of PARP activity, thereby facilitating the development of targeted treatments for genetic diseases associated with PARP dysfunction. Freshman Research Initiative, College of Natural Sciences, The University of Texas at Austin.