System analysis based on the cancer-immunity cycle identifies ZNF207 as a novel immunotherapy target for hepatocellular carcinoma

Background Immune checkpoint inhibitors as monotherapies for advanced hepatocellular carcinoma (HCC) fail to achieve satisfying results, while combination therapies show greater efficacy. Therefore, identifying new combined targets for immune checkpoint inhibitors could be promising. Methods We combined the cancer-immunity cycle score with weighted gene coexpression network and system analyses to screen immunosuppressive targets in HCC. In vitro and in vivo experiments were used to assess the effect of zinc finger protein 207 (ZNF207) on HCC immunity. RNA sequencing, metabolomic, cytokine array analysis, dual-luciferase reporter gene assay, and ChIP quantitative PCR assay were used to investigate the role of ZNF207 in tumor immunity regulation. Results The system analysis and experimental verification revealed ZNF207 as an immunosuppressive target in HCC. Hypoxia-induced upregulation of ZNF207 promoted HCC progression in immunocompetent mice while being associated with decreased CD8(+) T-cell infiltration and increased exhaustion. Mechanistically, the mitogen-activated protein kinase (MAPK)-chemokine C-X3-C-motif ligand axis was involved in ZNF207-mediated CD8(+) T-cell chemotaxis. Furthermore, ZNF207 transcriptionally regulated indoleamine 2,3-dioxygenase 1 and elevated kynurenine levels, leading to the exhaustion of CD8(+) T cells. Patients with lower ZNF207 expression were more sensitive to antiprogrammed cell death protein 1 (PD1) therapy, and silencing ZNF207 could be beneficial to anti-PD1 combination therapy. Conclusion Our study implicates ZNF207 in suppressing the HCC microenvironment and showed the feasibility of targeting ZNF207 during anti-PD1 therapy in HCC.