USP14 promotes head and neck squamous cell carcinoma progression via deubiquitinating and stabilizing CFL2

Aim To identify novel substrates of USP14 and elucidate the molecular mechanisms by which USP14 promotes head and neck squamous cell carcinoma (HNSCC) progression.Materials and methods USP14 expression patterns were examined in HNSCC tissues and cell lines. Functional effects were assessed using genetic knockout and overexpression models in vitro and in vivo. USP14-CFL2 interactions were evaluated by co-immunoprecipitation and GST pull-down assays. Deubiquitination activity was measured in vitro. Transcriptomic analysis and bioinformatics were used to identify downstream pathways and clinical relevance.Results USP14 was significantly overexpressed in HNSCC and correlated with poor prognosis. Genetic knockout of USP14 markedly suppressed HNSCC cell proliferation, migration, and tumor growth, while USP14 overexpression exerted opposite effects. Mechanistically, we identified CFL2 as a novel substrate of USP14; USP14 directly interacted with and deubiquitinated CFL2, thereby enhancing its stability by preventing proteasomal degradation. Clinically, CFL2 was also overexpressed in HNSCC and its elevated levels correlated with reduced overall survival. Functionally, CFL2 overexpression significantly rescued the anti-tumor effects of USP14 knockout, including impaired cell proliferation and migration.Conclusion In summary, our findings identify a novel USP14-CFL2 regulatory axis and establish USP14 as a critical promoter of HNSCC progression, acting through CFL2 deubiquitination and stabilization.