PLAUR, C3, and EMP3 coordinate tumor progression and immune evasion in clear cell renal cell carcinoma.

BACKGROUND: Clear cell renal cell carcinoma (ccRCC) progression is closely associated with the tumor microenvironment and immune evasion mechanisms. Identifying key molecular drivers is critical for advancing ccRCC diagnosis and therapy. METHODS: Differentially expressed genes (DEGs) were identified through analysis of the GSE6344 and GSE781 datasets. Weighted Gene Co-expression Network Analysis (WGCNA) was performed to uncover co-expression modules that exhibit significant correlation with clinical traits. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses, coupled with survival analysis, were employed to pinpoint potential hub genes. Single-cell RNA-seq data were analyzed to clarify cellular sources of PLAUR, C3, and EMP3. Functional validation of these genes was conducted using a range of assays, including RT-qPCR, Western blotting, CCK-8, wound healing, Transwell, and ELISA in both normal kidney cells and ccRCC cell lines. RESULTS: PLAUR, C3, and EMP3 were identified as hub genes enriched in extracellular matrix and immune-related pathways. All three genes were found to be overexpressed in ccRCC and associated with poor prognosis. Single-cell RNA-seq analysis revealed that PLAUR and C3 are primarily expressed in immune cells with detectable levels in tumor epithelial cells, whereas EMP3 exhibits a broader distribution, including strong expression in tumor epithelial cells. Silencing of PLAUR, C3, or EMP3 resulted in a marked inhibition of tumor proliferation, migration, and invasion. Notably, PLAUR knockdown exhibited the most substantial effect, disrupting immune evasion by reducing the levels of TGF-β, IL-10, and IL-6, while increasing the levels of IFN-γ, IL-2, and TNF-α in ccRCC cells co-cultured with T-cells. CONCLUSIONS: PLAUR, C3, and EMP3 promote ccRCC progression and immune evasion, with PLAUR acting as the dominant driver. Targeting PLAUR may provide a promising strategy to enhance anti-tumor immunity in ccRCC.