BMI1-induced CD127+KLRG1+ memory T cells enhance the efficacy of liver cancer immunotherapy.

The efficacy of HCC (hepatocellular carcinoma) immunotherapy is hindered by the limited reactivity and short duration of tumor-infiltrating T cells. These deficiencies may be ascribed to the proliferative ability of T cells. The primary objective of this study was to identify the key factor regulating tumor-infiltrating lymphocytes (TIL) proliferation within the HCC microenvironment. Through the utilization of tissue-infiltrated T cell proteomics and fraction proteomics, we analyzed the differential proteins in T cells among HCC, liver fibrosis, and hemangioma (serving as controls) groups. Additionally, we examined the differential regulatory TFs of T cells between the HCC and VH (volunteer healthy, as a control) groups. Using cyTOF and flow cytometry technologies, as well as generating CD8+ T-specific BMI1 knockout mice, we confirmed that BMI1 controls CD127+KLRG1+ memory cell differentiation. Through RNA-seq and MeRIP-seq, we verified that BMI1 regulates TCF1 expression independently of its classical function. Furthermore, by conducting Tyramide signal amplification (TSA) IHC analysis, employing a hydrodynamic mouse HCC model, and utilizing liver-specific nanoparticle targeting therapy, we demonstrated that BMI1 in HCC influences the proliferation of infiltrating CD8+T. BMI1 inhibition promotes effector T cell differentiation while suppressing memory T cell differentiation. Moreover, liver-specific BMI1 knockdown proves beneficial in ameliorating T cell dysfunction and decelerating HCC progression. Our research group has pioneered the exploration of the proteomics of HCC-infiltrated T cells, shedding light on the pivotal role of BMI1 in controlling CD127+KLRG1+ memory CD8+ T cell differentiation, which serves as the cornerstone for achieving immunotherapy efficacy in HCC.

SULT2B1-CS-DOCK2 axis regulates effector T-cell exhaustion in HCC microenvironment.

BACKGROUND AND AIMS: HCC is a malignant disease. Compared with tyrosine kinase inhibitors (the classical therapy), immune checkpoint inhibitors are more effective in the treatment of HCC, despite their limited efficacy. Among these restricted factors, exhaustion of tumor-infiltrated lymphocytes, especially CD8 + T cells, is a core event. We aimed to determine the key factors contributing to CD8 + T-cell infiltration in HCC and investigate the underlying mechanisms. APPROACH AND RESULTS: Using machine learning and multiplex immunohistochemistry analysis, we showed that dedicator of cytokinesis protein 2 (DOCK2) was a potential indicator of infiltrated CD8 + T cells in HCC. Using RNA sequencing, flow cytometry analysis, and mouse HCC models, we demonstrated that DOCK2 inactivation accounted for infiltrated CD8 + T-cell exhaustion in tumors. Using quasi-targeted metabolomics, mass spectrum, and mass cytometry by time of flight analysis, we found that cholesterol sulfate synthesized by sulfotransferase 2B1 in tumor cells suppressed DOCK2 enzymatic activity of T cells. Through virtual screening, molecular docking simulation, and experiments validation, we demonstrated that tolazamide reversed DOCK2 inactivation-mediated CD8 + T-cell exhaustion and enhanced anti-programmed death-ligand 1 antibody+apatinib immunotherapeutic effects on HCC. CONCLUSIONS: This study indicates that DOCK2 controls CD8 + T-cell infiltration in HCC, and cholesterol sulfate synthesized by sulfotransferase 2B1 in tumor cells promotes effector T-cell exhaustion. The findings suggest that the usage of conventional drugs affects immunotherapy efficacy in HCC patients.