scCirclehunter delineates ecDNA-containing cells using single-cell ATAC-seq, with a focus on glioblastoma.

In cancer, extrachromosomal DNA (ecDNA) contributes to tumor heterogeneity and is associated with poor prognosis, but studies on patient-derived ecDNA are relatively limited at single-cell resolution. Here, we introduce scCirclehunter, a framework designed to identify ecDNA from scATAC-seq data and assign ecDNA to specific cell populations. Leveraging scCirclehunter and available glioblastoma (GBM) datasets, we uncover the inter-cellular heterogeneity of ecDNA-carrying cells across GBM patients and trace the trajectories of malignant cells within a single patient that harbors multiple ecDNAs. By integrating scRNA-seq data, we use ecNR2E1 as an example to demonstrate that ecDNA drives tumor progression in GBM through several mechanisms. Additionally, our findings suggest a potential link between ecDNA and increased mitochondrial transfer frequency. Overall, scCirclehunter provides a novel framework for analyzing patient-specific ecDNAs with single-cell precision, offering insights into the role of ecDNA-carrying cells in driving GBM heterogeneity.