Single-cell resolution of an open chromatin signature in persister tumor cells

Cancer can recur when a subset of tumor cells, termed persister cells, survive therapy and re-enter the cell cycle. Through single-nucleus multi-omic profiling (single-nucleus RNA sequencing [snRNA-seq] and single-nucleus assay for transposase-accessible chromatin by sequencing [snATAC-seq]) of (1) non-malignant fallopian tubes and (2) treatment-naive and (3) neoadjuvant-chemotherapy-treated samples from patients with high-grade serous ovarian carcinoma (HGSOC), we identify a persister cell signature defining the chemotherapy-tolerant state. The chromatin features of the signature are detectable in residual tumors after treatment and in treatment-naive tumors from patients who later develop resistance. Further, the signature independently predicts chemotherapy response in metastatic HGSOC and patient-derived xenograft models. Cells enriched in the persister state display a subset of genes primed for expression before treatment, an altered cell cycle, and stress-response programs associated with poor clinical outcomes. These findings suggest that an intrinsic regulatory program primes tumor cells toward chemotherapy tolerance and reveal new vulnerabilities that can be targeted with chromatin-modifying agents to prevent cancer recurrence.