FTSJ1-mediated IL1RN mRNA instability promotes inflammation-driven hepatocellular carcinoma.

BACKGROUND: The role of 2'-O-methyltransferases in hepatocellular carcinoma (HCC) progression, particularly concerning inflammation, remains unclear. This study investigated their prognostic significance, identified key prognostic target FTSJ1, and elucidated its inflammatory-related biological functions and molecular mechanisms. METHODS: Transcriptomic data from The Cancer Genome Atlas-Liver Hepatocellular Carcinoma (TCGA-LIHC) were integrated to data of subtype HCC patients via consensus clustering based on 2'-O-methyltransferase expression. Single-gene survival analysis linked FTSJ1, FTSJ2, FTSJ3, and FBL to prognosis. A four-gene risk model was built. Multivariate COX regression identified independent risk factors. FTSJ1 expression and prognostic value were validated clinically using quantitative real-time polymerase chain reaction (qRT-PCR) and immunohistochemistry (IHC). Functional roles were assessed in vitro [Cell Counting Kit-8 (CCK-8), Transwell, apoptosis/cell cycle assays] and in vivo (xenograft models). Mechanisms were explored via RNA sequencing (RNA-seq), gene set enrichment analysis (GSEA), and inflammatory cytokine detection. RESULTS: Consensus clustering defined three subtypes. Subtype 1 (high 2'-O-methyltransferase expression) showed the worst prognosis. FTSJ1/2/3 and FBL correlated significantly with survival. The four-gene risk model predicted survival across cohorts [The Cancer Genome Atlas (TCGA)/Gene Expression Omnibus (GEO) datasets (GSE54236/GSE144269)]. FTSJ1 was an independent risk factor [multivariate Cox, hazard ratio (HR) =2.268, P=0.01] and significantly elevated in HCC tissues. Functionally, FTSJ1 knockdown inhibited proliferation and migration; induced G0/G1 arrest; promoted apoptosis in vitro; and suppressed tumor growth in vivo. Mechanistically, FTSJ1 drove HCC progression by reducing RNA stability of the key anti-inflammatory gene interleukin 1 receptor antagonist (IL1RN), leading to downregulated tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) and enhanced pro-inflammatory signaling. CONCLUSIONS: High 2'-O-methyltransferase abundance predicts poor HCC prognosis. FTSJ1 is a novel independent prognostic biomarker and oncogenic factor that promotes HCC progression by dysregulating the inflammatory response pathway, highlighting its translational potential in inflammation-driven HCC.