Osteopontin-driven TGF-β1 signaling via integrin αvβ3-NF-κB axis impairs NK cell function in head and neck squamous cell carcinoma.

In head and neck squamous cell carcinoma (HNSCC), an immunosuppressive tumor microenvironment (TME) frequently leads to natural killer (NK) cell dysfunction, but the molecular mechanisms underlying this impairment remain unclear. Here, we combined flow cytometry and multiplex immunohistochemistry to evaluate NK cells infiltration and functional status in HNSCC tumors. Bulk RNA-seq datasets from patient cohorts and single-cell RNA-seq data were analyzed to identify transcriptional correlates of NK cells dysfunction. Mechanistic studies in tumor cell lines assessed the role of osteopontin (OPN)-integrin αvβ3/NF-κB signaling in modulating TGF-β1 production and its effects on NK cell activity. NK cells in HNSCC tumors exhibited reduced infiltration and diminished activation marker expression, coinciding with high OPN levels in the TME. Transcriptomic analyses demonstrated a strong inverse correlation between tumor SPP1 (encoding OPN) expression and NK cells abundance. Mechanistically, tumor-derived OPN engaged integrin αvβ3 to activate NF-κB signaling, inducing robust TGF-β1 secretion that suppressed NK cell activation and cytotoxic function. Single-cell RNA-seq analysis further confirmed the exhausted functional states of NK cells within the HNSCC TME. Tumor-derived OPN promotes immune evasion in HNSCC by driving TGF-β1-mediated suppression of NK cell activity. These findings highlight the OPN-TGF-β1 axis as a potential therapeutic target for restoring NK cell-mediated immunity in HNSCC.