Identification of a cancer stem cell-like subpopulation that promotes HCC metastasis.

Background & Aims: Cancer stem cells (CSCs) are well-established drivers of tumorigenesis, but their role in regulating tumor metastasis remains poorly understood. Here, we report the identification and characterization of a cluster of metastasis-promoting CSC-like cells in hepatocellular carcinoma (HCC). Methods: CSC-like cells in HCC were identified through the analysis of single cell RNA-sequencing data from 19 HCC samples. The stemness and invasive characteristics of these cells were evaluated using bioinformatical analyses of nine clinical cohorts and experimental validations. Spatial transcriptomics sequencing of 12 HCC samples revealed the cellular interactions between the CSC-like cells and tumor microenvironments, which were validated through gene co-expression analyses and immunohistochemistry. Finally, signaling pathway blockade was used to assess the potential clinical application of CSC-like cells. Results: Through comprehensive analyses of single cell RNA-sequencing data from 19 patients with HCC and spatial transcriptomics data from 12 patients with HCC, a metastasis-promoting CSC-like subpopulation was identified. These CSC-like cells expressed high levels of epithelial-mesenchymal transition genes and were associated with poor prognosis of HCC. Histologically, CSC-like cells were enriched in highly aggressive tumors, especially in intrahepatic disseminated foci, where they interacted with immune cells. Functionally, CSC-like cells induced macrophage M2 polarization and T cell exhaustion through the ICAM1 signaling pathway, forming immunosuppressive microenvironments. Downregulation of ICAM1 expression in CSC-like cells suppressed macrophage M2-polarization and T cell exhaustion, thereby reversing antitumor immune effects. Conclusions: Our study identified a metastasis-promoting CSC subpopulation, providing a potential perspective for CSC-targeted therapies in HCC. Impact and implications: The heterogeneity of CSCs in HCC has been identified, yet the identification and characterization of metastasis-promoting CSC subpopulations remain unexplored. Here, we identified a CSC-like tumor cell subpopulation that promotes HCC metastasis by increasing cell invasiveness and suppressing antitumor immune responses via the ICAM1 signaling pathway. Our study uncovers novel mechanisms of HCC metastasis from the perspective of CSCs, and proposes potential tumor therapeutic strategies by inhibiting cellular interactions between CSC-like cells and immune cells.