Integrative Analysis of Single-Cell and Spatial Transcriptomics Reveals Intratumor Heterogeneity Shaping the Tumor Microenvironment in Hepatocellular Carcinoma

Background: Intratumour heterogeneity (ITH) is one of the key characteristics of cancer and is closely associated with patient prognosis, treatment resistance, and tumor metastasis. Nevertheless, the study of ITH in hepatocellular carcinoma (HCC) remains limited. Methods: The present study elucidated the influence of ITH on the tumor microenvironment (TME) in HCC. We applied Non-negative Matrix Factorization (NMF) analysis to a cohort of 78 single-cell RNA sequencing (scRNA-seq) HCC samples to systematically characterize ITH. Furthermore, by integrating spatial transcriptomics (ST) data from five HCC patients, we comprehensively analyzed the spatial organization and functional properties of distinct niches within HCC. We conducted a detailed analysis of the cell-type co-localization relationships within the TME and constructed a comprehensive atlas of HCC spatial organization. Results: We observed a co-localization relationship between hypoxia tumor cells, plasmalemma vesicle-associated protein (PLVAP+) endothelial cells (EC), and vascular endothelial growth factor A (VEGFA+) cancer-associated fibroblasts (CAF), suggesting a key role for hypoxia tumor cells in VEGFA+ CAF transformation and tumor angiogenesis. We identified a unique boundary region enriched with dendritic cells1 (DC1), interferon-expressing tumor cells, lymphatic EC, C–X–C Motif Chemokine Ligand 10 (CXCL10+) macrophages (Mac), and secreted phosphoprotein 1 (SPP1+) Mac located between the tumor-infiltrating immune cells and tumor regions. Furthermore, we found that CXCL10+ Mac and SPP1+ Mac, despite co-localizing in the boundary region, exhibit distinct functions, which may be attributed to their unique spatial locations, with the former being closer to the immune-infiltrated region and the latter more proximal to the tumor area. Conclusions: Our study highlights the critical role of spatial interactions between tumor cells and the microenvironment in HCC. The findings offer new insights into ITH and underscore the importance of spatial organization in understanding cancer biology and designing future precision therapies.