180P - Unravelling drug resistance in high-grade serous ovarian cancer through clonal dynamics and single-cell heterogeneity analysis

Background

High-grade serous ovarian cancer (HGSOC) presents significant challenges due to extensive intra-tumoural heterogeneity and development of drug resistance. This study aims to investigate the clonal dynamics and single-cell gene expression profiles of HGSOC cells under the selective pressure of anticancer drugs.

Methods

HGSOC cell lines were barcoded through lentiviral transfection, assigning each cell a unique barcode to track clonal evolution under carboplatin, paclitaxel, and olaparib exposure. Single-cell RNA sequencing (scRNA-seq) was employed to analyse gene expression profiles of drug-persistent cell populations, providing insights into cellular heterogeneity and evolutionary dynamics. This approach allows for the identification of rare populations and outlier cells that are not detectable through pooled cell analysis.

Results

Our findings highlighted the presence of pre-existing persistent clones prior to any drug exposure that were positively selected under drug pressure. ScRNA-seq analysis revealed distinct gene expression signatures associated with resistance to each drug. Olaparib exposure led to the most heterogeneous final cell populations, with notable upregulation of genes associated with DNA repair pathways and cell cycle regulation, including TGF-Beta and EMT-related genes. Carboplatin-persistent cells showed reduced heterogeneity, with significant enrichment of genes related to oxidative stress response and apoptosis regulation, such as G2/M checkpoint and MYC. Paclitaxel-persistent cells exhibited unique transcriptional profiles, including activation of genes involved in cytoskeletal organization and hypoxia, such as Hypoxia and E2F family transcription factors.

Conclusions

Integrating DNA barcoding and scRNA-seq provides a comprehensive view of HGSOC adaptation under therapeutic pressure. Our findings emphasize the critical role of single-cell heterogeneity in drug resistance and underscore the potential for tailored therapeutic strategies to mitigate resistance. These insights pave the way for designing adaptive treatment regimens that anticipate and counteract tumour evolution, ultimately improving outcomes for HGSOC patients.

Editorial acknowledgement

Clinical trial identification

Legal entity responsible for the study

The Institute of Cancer Research.

Funding

CRUK, Wellcome Trust, NIHR (National Institute for Health Research).

Disclosure

S. Banerjee: Financial Interests, Personal, Advisory Board: Immunogen, Mersana, MSD, Roche, AstraZeneca, GSK, Oncxerna, Shattuck Labs, Novartis, Epsilogen, Seagen, Eisai, Regeneron, Verastem, Myriad; Financial Interests, Personal, Invited Speaker: AstraZeneca, GSK, Takeda, Medscape, Research to Practice, Peerview, Novocure, AbbVie; Financial Interests, Personal, Stocks/Shares: Perci Health; Financial Interests, Institutional, Research Grant: AstraZeneca, GSK; Non-Financial Interests, Personal, Principal Investigator, Phase II clinical trial Global lead, ENGOTov60/GOG3052/RAMP201: Verastem; Non-Financial Interests, Personal, Principal Investigator, ENGOT-GYN1/ATARI phase II international trial (academic sponsored): AstraZeneca; Non-Financial Interests, Personal, Principal Investigator, Academic sponsored trial PI (MONITOR-UK): GSK; Non-Financial Interests, Personal, Advisory Role, Medical advisor to UK Ovarian Cancer Charity: Ovacome Charity; Non-Financial Interests, Personal, Leadership Role, Board Member: International Cancer Foundation (ICF). U. Banerji: Financial Interests, Personal, Advisory Board, Advisory Board Member: Pegasy, Carrick Therapeutics; Financial Interests, Personal, Advisory Board: Pharmenable, Ellipses Pharma; Financial Interests, Personal, Full or part-time Employment, Employed by the Institute of Cancer Research: The Institute of Cancer Research; Financial Interests, Institutional, Research Grant, Pre-clinical grant: Verastem Oncology; Financial Interests, Institutional, Research Grant, Preclinical Research Grant: Avacta; Non-Financial Interests, Personal, Principal Investigator: Various pharma companies. All other authors have declared no conflicts of interest.