ecDNA hubs drive cooperative intermolecular oncogene expression [scRNA and scATAC-Seq]

Extrachromsomal DNA (ecDNA) are prevalent in human cancers and are associated with high oncogene expression as well as altered chromatin. Here we show that multiple ecDNAs cluster in the nucleus during interphase to form ecDNA hubs, where oncogene transcription preferentially occurs. Single-cell multiomics, single-molecule sequencing, and 3D enhancer connectome reveal MYC ecDNAs are heterogenous in primary sequence and that ecDNA hubs support ectopic and intermolecular enhancer-promoter interactions. Bromodomain-containing protein 4 (BRD4) extensively occupies ecDNA regulatory elements, and inhibition by JQ1 disperses ecDNA hubs and preferentially reduces ecDNA oncogene transcription. Two amplified oncogenes can intermix in ecDNA hubs, engage in intermolecular enhancer-promoter interactions, and transcription is uniformly sensitive to JQ1. Thus, ecDNA hubs – nuclear bodies of many ecDNAs tethered by proteins – are platforms for cooperative oncogene transcription. The recognition of ecDNA hubs as units of oncogene function and diversification has potentially broad implications for cancer cell evolution and therapy. Overall design: Single cell multiome ATAC + gene expression profiling of COLO320-DM and COLO320-HSR cell lines.