Proteomics and Functional Validation Reveal IRAK4-NF-κB Axis as a Key Regulator of CD8+ T Cell Dysfunction in Glioblastoma Multiforme Immune Evasion

This study explores the critical role of interleukin-1 receptor-associated kinase 4 (IRAK4) in regulating CD8+ T cell dysfunction and immune evasion in glioblastoma multiforme (GBM), a highly aggressive brain tumor with limited treatment efficacy, by employing a comprehensive approach involving proteomics and functional assays to identify IRAK4 as a key regulator that activates the NF-κB pathway, thereby impairing CD8+ T cell cytotoxicity and facilitating tumor progression, with high-throughput proteomic techniques applied to clinical GBM samples from the CPTAC database revealing 1,205 differentially expressed proteins including a significant upregulation of IRAK4, while in vitro experiments utilizing CRISPR/Cas9 to knock out or overexpress IRAK4 in CD8+ T cells assessed cytotoxicity through LDH release and IFN-γ/TNF-α production alongside co-culture effects on GBM cell lines such as GL261 and G422, and in vivo validation through an orthotopic murine GBM model tested IRAK4's impact on tumor growth and CD8+ T cell infiltration, with NF-κB inhibition via Triptolide reversing these effects, complemented by bioinformatics analyses including GO and KEGG enrichment as well as Lasso and random forest modeling that linked IRAK4 to immune evasion pathways, ultimately showing that IRAK4 upregulation correlates with NF-κB activation to suppress CD8+ T cell function, enhance GBM proliferation, migration, and invasion, and that knockout boosts cytotoxicity while overexpression accelerates tumor growth and reduces infiltration, with NF-κB inhibition offering a potential therapeutic target, suggesting the IRAK4-NF-κB axis as a novel immune checkpoint in GBM that could restore antitumor immunity and overcome immune evasion to improve treatment outcomes, though limitations such as a small sample size affecting generalizability, a focus solely on CD8+ T cells overlooking other immune cell contributions, and the need for further clinical trials to validate therapeutic potential should be noted.