Abstract PR006: Single-molecule and single-cell epigenetics: Decoding the epigenome for cancer research and diagnostics

Abstract

Abstract Genes and genomic elements are packaged by chromatin structures that regulate their activity. We developed a novel high-throughput single-molecule imaging technology to decode combinatorial modifications on millions of individual nucleosomes. We apply this technology to image nucleosomes and delineate their combinatorial epigenetic patterns, and how these patterns are deregulated in cancer. In addition, we adapt single-cell technologies based on CyTOF to profile the global levels of multiple histone modifications in single cells, thus revealing epigenetic heterogeneity in cancer. Our research focuses on pediatric gliomas harboring lysine to methionine substitution of residue 27 on histone H3 (K27M). We provide evidence for widespread effects of the H3-K27M oncohistone on multiple core epigenetic pathways, and highlight the capability of single-molecule and single-cell tools to reveal mechanisms of chromatin deregulation and heterogeneity in cancer. We also harness the single-molecule technology as a novel liquid biopsy approach, by comprehensively profiling combinatorial epigenetic marks of plasma-isolated nucleosomes. Applying this analysis to a cohort of plasma samples detect colorectal cancer at high accuracy and sensitivity, even at early stages. Finally, combining this proteomic analysis with single-molecule DNA sequencing reveals the tissue-of-origin of the tumor. Citation Format: Efrat Shema. Single-molecule and single-cell epigenetics: Decoding the epigenome for cancer research and diagnostics. [abstract]. In: Proceedings of the AACR Special Conference: Cancer Epigenomics; 2022 Oct 6-8; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2022;82(23 Suppl_2):Abstract nr PR006.