Kinetic analysis of platinum-induced DNA-DNA crosslink formation and repair

Abstract

Cisplatin, carboplatin, and oxaliplatin are FDA-approved platinum-based anti-tumor drugs used in chemotherapy regimens. Their therapeutic efficacy is principally attributed to the formation of DNA intrastrand and interstrand cross-links, which disrupt vital cellular processes such as DNA replication, ultimately triggering apoptosis and cell death. Despite their clinical significance, the emergence of drug resistance and adverse side effects pose substantial challenges to the efficacy and tolerability of platinumbased chemotherapy In prior investigations, our laboratory aimed to address these challenges through the development of comprehensive ultraperformance liquid chromatography-selective ion monitoring (UPLC-SIM) assays to quantify various types of DNA intrastrand cross-links induced by platinum drugs, including 1,2-GG, 1,2AG, 1,3-GCG, and 1,3-GTG cross-links. Such analytical methodologies provide critical insights into the distinct contributions of individual intrastrand cross-links to the pharmacological activity of platinum drugs. Using this assay, I quantified platinum cross-link formation in CTDNA and in cell culture. Furthermore, I sought to enhance our understanding of platinum drug-induced DNA damage by optimizing the alkaline COMET chip assay. This optimized assay enabled the assessment of nucleotide excision repair (NER) incision rates in cells exposed to platinum drugs. Through this approach, I aim to better understand the mechanisms of resistance to platinum therapies and the role of DNA repair pathways play in the etiology of resistance. Throught this understanding, we may facilitate the development of more effective and targeted therapeutic strategies to combat cancer.