Spatial remodeling of the tumor immune microenvironment in hepatocellular carcinoma with cirrhosis driven by Treg-CD8⁺T cell crosstalk via the SPP1-ITGA4 axis.

[OBJECTIVE] The tumor microenvironment (TME) of hepatocellular carcinoma (HCC) is shaped by underlying liver pathology, with potentially distinct features in HCC without cirrhosis (Non-cirrHCC) compared to HCC with cirrhosis (CirrHCC); however, these background-specific differences remain incompletely understood. This study aimed to systematically characterize and compare the cellular composition, spatial organization, and immunoregulatory interactions of the TME between Non-cirrHCC and CirrHCC.

[METHODS] Total 278 HBV-positive cases and mapped 2,837,999 cells across 11 major cell types were applied for spatial analysis. Subsequently, we integrated the spatial data with publicly available single-cell RNA-seq datasets for downstream analysis.

[RESULTS] Comparative analysis demonstrated marked differences in immune cell composition between Non-cirrHCC and CirrHCC, with CirrHCC characterized by a pronounced decline in functionally active CD8⁺ T cells. We identified 10 distinct heterotypic cellular neighborhoods (HCNs) representing the heterotypic architecture of the tumor microenvironment. Notably, CirrHCC exhibited an immunosuppressive microenvironment with increased spatial proximity between Tregs and CD8T_CD107a⁺ cells, leading to reduced CD8⁺ T cell functional signaling. Integration with single-cell RNA sequencing from public database further indicated that, in CirrHCC, Tregs preferentially interact with the CD8T_CD107a+ cells, potentially mediated by the SPP1-ITGA4 signaling axis.

[CONCLUSION] In conclusion, CirrHCC promotes a spatially organized Treg-CD8T_CD107a⁺ suppressive niche that constrains CD8⁺ T cell effector function in HCC, with SPP1-ITGA4 emerging as a potential mediating pathway.