XPF-ERCC1 · Structural and kinetic studies of XPF/ERCC1-DNA complex for drug discovery

Cancer chemotherapeutic drugs, such as platinum agents, work by producing DNA damage that causes cell-cycle arrest and cell death. However, DNA repair pathways can enable tumour cells to survive DNA damage induced by chemotherapeutic treatments. Platinum resistance is a major clinical problem in cancer treatment and there is a considerable interest in inhibitors of DNA repair pathways, that can increase efficiency of chemotherapy, when administered together. An attractive target to circumvent platinum resistance is XPF/ERCC1 heterodimer. XPF/ERCC1 is a structure-specific endonuclease that cleaves double- to single-stranded DNA junctions, and its function is directly linked to repair of DNA cross-links induced by platinum agents. Here, we propose a multi-disciplinary methodology that combines structural studies by Nuclear Magnetic Resonance Spectroscopy with kinetic studies by Kinetic Capillary Electrophoresis to elucidate the mechanisms of XPF/ERCC1 function and modulate its activity for potential therapeutic benefit. Structural and molecular insights of DNA binding will be coupled with kinetic rates of DNA cleavage and enzyme/substrate interactions. The combined information will be used to develop XPF/ERCC1 inhibitors by in silico screening. Currently structure-kinetics relationship is not well explored in drug discovery, although the residence lifetime of a drug determines the duration of a pharmacological effect. The ability to combine structural and kinetic parameters in validating computational hits should identify compounds with desired pharmacological properties at early stages and facilitate faster optimization phase. The research proposed here is highly beneficial to public health, because it would allow to develop combination therapies for cancer treatment.