Multi-Omics Analysis and Mechanistic Validation Reveal RPS8 as a Novel Prognostic Biomarker and Therapeutic Target for Hepatocellular Carcinoma.

Despite its aggressiveness and unfavorable prognosis, the key molecular drivers of Hepatocellular carcinoma (HCC) are still not fully defined. The role of ribosomal protein S8 (RPS8) in HCC development and its regulatory mechanisms received little attention. We investigated the role of RPS8 in HCC progression by delineating its biological functions, clinical relevance, and mechanistic underpinnings. We conducted comprehensive multi-omics analysis using public datasets (TCGA, GEO) to evaluate RPS8 expression and its prognostic value in HCC. Single-cell RNA-seq was utilized to map the distribution of RPS8 expression within the tumor microenvironment. The biological functions of RPS8 were validated through a series of in vitro assays (e.g., colony formation, Transwell, wound healing) and in vivo subcutaneous xenograft models using RPS8 knockdown and overexpression systems. Whole-transcriptome sequencing was performed to identify the downstream pathways regulated by RPS8. RPS8 was elevated in HCC at both the transcriptional and protein levels, and its overexpression independently signaled poor prognosis. In functional assays, RPS8 increased HCC cell proliferation, migration, and invasion in vitro and stimulated tumor growth in vivo. This pro-tumorigenic activity was associated with the induction of epithelial-mesenchymal transition (EMT) and angiogenesis. Mechanistically, we revealed that RPS8 exerts these effects by activating the endoplasmic reticulum (ER) stress pathway. Furthermore, high RPS8 expression was associated with a remodeled tumor immune microenvironment, characterized by increased CD8+ T cell infiltration. Findings identify RPS8 as a critical oncogene that promotes HCC progression via activation of ER stress. RPS8 can be leveraged as a prognostic biomarker and as a potential focus of therapy in HCC.