Oral Presentation NSW State Cancer Conference 2023

Single cell analysis assigns key roles to cellular plasticity and distinct DNA repair signatures in platinum-resistant ovarian cancer cells (#58)

George Joun 1 , Yue Cao 2 3 , James Cornwell 4 , Anna deFazio AM 1 5 6 7 , Jean Yang 2 3 , Mohit Kumar Jolly 8 , Naisana Seyedasli 1 5
  1. School of Medical Sciences, Faculty of Medicine and Health, University of Sydney, Westmead, NSW, Australia
  2. Sydney Bioinformatics and Biometrics Group, School of Mathematics, Faculty of Science, University of Sydney, Camperdown NSW , NSW , Australia
  3. The Charles Perkins Centre, University of Sydney, Camperdown, NSW, Australia
  4. Laboratory of Cancer Biology and Genetic, Centre for Cancer Research, National Cancer Institute, National Institutes of Health, Bathesda, MD, USA
  5. Centre for Cancer Research, The Westmead Institute for Medical Research, Westmead, NSW, Australia
  6. The Daffodil Cen, University of Sydney, Camperdown, NSW, Australia
  7. Department of Gynaecological Oncology, Westmead Hospital, Westmead, NSW, Australia
  8. Centre for BioSystems Science and Engineering, Indian Institute of Science, Bangalore , NSW, India

Platinum-resistance is a major confounding factor in the clinical management of ovarian cancer resulting in close to 70% rate of relapse of treatment-resistant disease. In this study, we have used patient-derived cells from the Australian Ovarian Cancer Study to highlight the cellular and molecular dynamics of high grade serous ovarian cancer cells during the course of platinum treatment. Using an array of techniques, including live single cell tracking and single cell sequencing, combined with quantitative proteomics, we have demonstrated inherent cellular and molecular patterns of response to platinum, stratified along the resistance spectrum. Tracking of fluorescent-tagged ovarian cancer cells with the cell cycle reporter, FUCCI, clearly demonstrated distinct patterns of cell cycle plasticity among clonal lineages with varied levels of platinum response. Further, single cell sequencing during the course of treatment, has highlighted key signatures within defined clusters with heightened response to platinum, with the remainder clusters demonstrating a clear resistance to treatment. Quantitative proteomics of chromatin-bound protein fractions in single cell-derived clones with varied response to platinum, further highlighted discrete signatures of arrest with key elements of DNA repair machinery and nuclear skeletal remodeling. Altogether, our findings provide a comprehensive single-cell resolution overview of cellular and molecular dynamics in high grade ovarian cancer cells during the course of platinum response. An image that will further elucidate the mechanisms behind development of resistance, providing biomarkers for molecular prognostics and targets for novel treatments.