Single-cell transcriptomic profiling of immune microenvironment remodeling in unresectable hepatocellular carcinoma after TACE combined therapies

Background The mechanisms underlying immune microenvironment remodeling remain unclear for patients with unresectable hepatocellular carcinoma (uHCC) undergoing transarterial chemoembolization (TACE) combined with tyrosine kinase inhibitors (TKIs) and immune checkpoint inhibitors (ICIs). This study aims to identify the key features that change following the combination therapy in patients with uHCC. Methods Single-cell transcriptomic profiling was conducted on uHCC samples from the control group, pre-treatment group, and post-treatment group. The Cancer Genome Atlas (TCGA) database was obtained for prognostic analysis. Enriched genes and pathways were identified, and the association and underlying mechanisms of the identified sub-cluster of cells were elucidated in relation to other cellular components. Results A total of 82,687 cells were obtained from seven patients with uHCC. In the pre-treatment group, the CancerCells_1 was associated with epithelial-mesenchymal transition, indicating a poor prognosis, as evidenced by data from 370 HCC patients in TCGA database. In the post-treatment group, a high proportion of macrophages_FOLR2 was observed corresponding to an elevated interferon response signature score and a diminished pro-angiogenic signature score. The exhaustion of CD8 + effector T cell (CD8Teff) was mitigated by downregulating the notable expression of BHLHE40 and CXCL13. Following treatment, there was an increase in liver sinusoidal endothelial cell (LSEC), while both angiogenesis and TGF-β pathway scores were reduced. Notable changes were observed in the interactions across different cells, particularly concerning the key signatures of LGALS9_HAVCR2, CSF1_CSF1R, and VEGFB_FLT1. Conclusion After combined treatment, uHCC patients were characterized by macrophages_FOLR2, CD8Teff, and LSEC, indicating a remodeling of the immune microenvironment.