The chromatin landscape of high-grade serous ovarian cancer metastasis identifies regulatory drivers in post-chemotherapy residual tumour cells

• Published in: Communications biology 2024-09, Vol.7 (1), p.1211-12, Article 1211
• Main Authors: Croft, W., Pounds, R., Jeevan, D., Singh, K., Balega, J., Sundar, S., Williams, A., Ganesan, R., Kehoe, S., Ott, S., Zuo, J., Yap, J., Moss, P.
• Format: Article
• Language: English
• Subjects: 14; 14/1; 38; 38/23; 45; 45/23; 631/67/1517/1709; 631/67/69; Biomedical and Life Sciences; Chemoresistance; Chemotherapy; Chromatin; Chromatin - genetics; Chromatin - metabolism; Drug Resistance, Neoplasm - genetics; Female; Gene expression; Gene Expression Regulation, Neoplastic; Humans; Life Sciences; Lymphoid cells; Metastases; Metastasis; Microenvironments; Neoplasm Metastasis; Nuclear receptors; Ovarian cancer; Ovarian Neoplasms - drug therapy; Ovarian Neoplasms - genetics; Ovarian Neoplasms - metabolism; Ovarian Neoplasms - pathology; p53 Protein; Therapeutic targets; Transcription factors; Tumor Microenvironment; Tumors
• ISSN: 2399-3642; 2399-3642
• DOI: 10.1038/s42003-024-06909-9

Disease recurrence following chemotherapy is a major clinical challenge in ovarian cancer (OC), but little is known regarding how the tumour epigenome regulates transcriptional programs underpinning chemoresistance. We determine the single cell chromatin accessibility landscape of omental OC metastasis from treatment-naïve and neoadjuvant chemotherapy-treated patients and define the chromatin accessibility profiles of epithelial, fibroblast, myeloid and lymphoid cells. Epithelial tumour cells display open chromatin regions enriched with motifs for the oncogenic transcription factors MEIS and PBX. Post chemotherapy microenvironments show profound tumour heterogeneity and selection for cells with accessible chromatin enriched for TP53, TP63, TWIST1 and resistance-pathway-activating transcription factor binding motifs. An OC chemoresistant tumour subpopulation known to be present prior to treatment, and characterised by stress-associated gene expression, is enriched post chemotherapy. Nuclear receptors RORa, NR2F6 and HNF4G are uncovered as candidate transcriptional drivers of these cells whilst closure of binding sites for E2F2 and E2F4 indicate post-treated tumour having low proliferative capacity. Delineation of the gene regulatory landscape of ovarian cancer cells surviving chemotherapy treatment therefore reveals potential core transcriptional regulators of chemoresistance, suggesting novel therapeutic targets for improving clinical outcome. Interrogating the single cell chromatin accessibility landscape of Ovarian Cancer metastatic tumour cells that reside following chemotherapy treatment highlights potential regulatory drivers of chemoresistance.