PRKDC orchestrates immune evasion in hepatocellular carcinoma through CSF1/CSF1R-mediated M2 macrophage polarization

Hepatocellular carcinoma (HCC) remains highly lethal, with immune evasion limiting treatment efficacy. Tumor-associated macrophages (TAMs) are abundant in HCC and tend to polarize toward an M2-like phenotype, contributing to immune evasion. Although PRKDC is implicated in tumor progression, its role in the HCC tumor microenvironment (TME), especially in TAMs, remains unclear. We established mouse Hepa1-6 oe− PRKDC cells and subcutaneous and orthotopic HCC models. PRKDC overexpression enhanced malignant phenotypes in vitro and increased tumor growth in vivo. Olink proteomics, RNA sequencing, qPCR, ELISA, and IHC indicated that PRKDC upregulated CSF1. Database analyses further supported CSF1R as the primary CSF1 receptor, and single-cell analysis showed CSF1R enrichment in TAMs. CSF1R knockdown in mouse RAW264.7 macrophages reduced IL-4-induced M2 marker expression. IHC, co-culture, and flow cytometry showed increased expression of M2-like TAM markers in the oe- PRKDC group. Macrophage phagocytosis assays further indicated that PRKDC -mediated CSF1 upregulation was associated with increased HCC cell resistance to phagocytosis. Collectively, PRKDC may promote HCC progression by upregulating CSF1, activating the CSF1/CSF1R pathway, and inducing M2-like TAM polarization, thereby impairing phagocytosis and contributing to immune evasion. The PRKDC -CSF1/CSF1R-TAM axis may be a potential therapeutic target in HCC.