Chromatin accessibility module identified by single-cell sequencing underlies the diagnosis and prognosis of hepatocellular carcinoma.

BACKGROUND: Hepatocellular carcinoma (HCC) is notorious for its aggressive progression and dismal prognosis, with chromatin accessibility dynamics emerging as pivotal yet poorly understood drivers. AIM: To dissect how multilayered chromatin regulation sustains oncogenic transcription and tumor-stroma crosstalk in HCC, we combined multiomics single cell analysis. METHODS: We integrated single-cell RNA sequencing and paired single-cell assay for transposase-accessible chromatin with sequencing data of HCC samples, complemented by bulk RNA sequencing validation across The Cancer Genome Atlas, Liver Cancer Institute, and GSE25907 cohorts. Cell type-specific chromatin architectures were resolved via ArchR, with regulatory hubs identified through peak-to-gene linkages and coaccessibility networks. Functional validation employed A485-mediated histone 3 lysine 27 acetylation suppression and small interfering RNA targeting DGAT1. RESULTS: Malignant hepatocytes exhibited expanded chromatin accessibility profiles, characterized by increased numbers of accessible peaks and larger physical regions despite reduced peak intensity. Enhancer-like peaks enriched in malignant regulation, forming long-range hubs. Eighteen enhancer-like peak-related genes showed tumor-specific overexpression and diagnostic accuracy, correlating with poor prognosis. Intercellular coaccessibility analysis revealed tumor-stroma symbiosis via shared chromatin states. Pharmacological histone 3 lysine 27 acetylation inhibition paradoxically downregulated DGAT1, the hub gene most strongly regulated by chromatin accessibility. DGAT1 knockdown suppressed cell proliferation. CONCLUSION: Multilayered chromatin reprogramming sustains HCC progression through tumor-stroma crosstalk and DGAT1-related oncogenic transcription, defining targetable epigenetic vulnerabilities.