Abstract AP05: OVARIAN CANCER-ASSOCIATED RAD51D MUTATIONS WHICH IMPAIR ITS INTERACTION WITH XRCC2 RESULT IN DNA REPAIR DEFICIENCY

The proficiency of ovarian cancer cells to repair DNA double-strand breaks (DSBs) by homologous recombination (HR) is a key determinant in predicting response to targeted therapies such as PARP inhibitors (PARPi). The RAD51 paralogs act downstream of BRCA1/2 to facilitate HR. Numerous epidemiological studies have linked mutations in the RAD51 paralogs with hereditary ovarian cancer predisposition. Despite their substantial links to cancer predisposition and development, RAD51 paralog function during HR has remained elusive, in part due to limitations in studying recombination events downstream of RAD51 filament formation. Here we investigate the impact of cancer-associated mutations in the RAD51 paralog, RAD51D, using yeast 2/3-hybrid assays to screen for altered protein-protein interactions. Following the identification of mutations that disrupt the interaction between RAD51D and XRCC2 in yeast, we validated the interaction by co-immunoprecipitation in human cells. Importantly, we determined the impact of these mutations on HR-proficiency using a direct-repeat recombination assay. By characterizing the impact of cancer-associated mutations in the RAD51 paralogs on HR-proficiency, we aim to develop more effective predictive models for therapeutic sensitivity and resistance in patients who harbor similar mutations in these essential genes.

Citation Format: Robert A. Baldock, Catherine A. Pressimone, Jared M. Baird, Anton Y. Khodakov, Yoav Karpenshif, Edwige B. Garcin, Stéphanie Gon, Mauro Modesti, Kara A. Bernstein. OVARIAN CANCER-ASSOCIATED RAD51D MUTATIONS WHICH IMPAIR ITS INTERACTION WITH XRCC2 RESULT IN DNA REPAIR DEFICIENCY [abstract]. In: Proceedings of the 12th Biennial Ovarian Cancer Research Symposium; Sep 13-15, 2018; Seattle, WA. Philadelphia (PA): AACR; Clin Cancer Res 2019;25(22 Suppl):Abstract nr AP05.

A new experimental cell for in situ and operandoX-ray absorption measurements in heterogeneous catalysis

A new X-ray absorption cell dedicated to in situ and operando experiments in heterogeneous catalysis has been built and tested. The cell consists of several boron nitride and stainless steel plates linked together using graphite seals. It allows the measurement of XANES and EXAFS spectra of heterogeneous catalysts within a wide range of photon energies in transmission mode under the flow of various oxidative and reductive gas mixtures at elevated temperatures. The cell is compact and easy to build. Catalysts are loaded into the cell as powders. The use of boron nitride and a small beam pathlength in the cell result in a low absorption of the X-ray beam at lower energies. The cell was tested by in situ characterizing cobalt species during oxidative and reductive pre-treatments of a silica-supported Fischer-Tropsch catalyst. An operando study of methanol conversion over alumina-supported molybdenum catalysts was also carried out.