RNASE4 promotes malignant progression and chemoresistance in hypoxic glioblastoma via activation of AXL/AKT and NF-κB/cIAPs signaling pathways.

Glioblastoma (GBM) is the most malignant brain tumor frequently characterized by a hypoxic microenvironment. In this investigation, we unveiled unprecedented role of Ribonuclease 4 (RNASE4) in GBM pathogenesis through integrative methodologies. Leveraging The Cancer Genome Atlas (TCGA) dataset and clinical specimens from normal brain tissues, low- and high-grade gliomas, alongside rigorous in vitro and in vivo functional analyses, we identified a consistent upregulation of RNASE4 correlating with advanced GBM pathological stages and poor clinical survival outcomes. Functional assays corroborated the pivotal influences of RNASE4 on key tumorigenic processes such as cell proliferation, migration, invasion, stemness properties and temozolomide (TMZ) resistance. Further, Gene Set Enrichment Analysis (GSEA) illuminated the involvement of RNASE4 in modulating epithelial-mesenchymal transition (EMT) via activation of AXL, AKT and NF-κB signaling pathways. Furthermore, recombinant human RNASE4 (hRNASE4)-mediated NF-κB activation through IκBα phosphorylation and degradation could result in the upregulation of inhibitors of apoptosis proteins (IAPs), such as cIAP1, cIAP2, and SURVIVIN. Notably, treating RNASE4-induced TMZ-resistant cells with the SURVIVIN inhibitor YM-155 significantly restored cellular sensitivity to TMZ therapy. Herein, this study positions RNASE4 as a potent prognostic biomarker and therapeutic target, offering new insights into molecular pathogenesis of GBM and new avenues for future therapeutic interventions.