PGK1 dysregulation promotes head and neck cancer progression through p21 downregulation

Head and neck squamous cell carcinoma (HNSCC) is an aggressive malignancy characterized by poor prognosis and high recurrence rates. Phosphoglycerate kinase 1 (PGK1), a key glycolytic enzyme, has been implicated in cancer progression through both metabolic and non-metabolic functions. However, its functional role in HNSCC remains largely unclear. In this study, we investigated the expression and biological significance of PGK1 in HNSCC. Single-cell transcriptomic analysis was used to examine PGK1 expression across normal, premalignant, and malignant epithelial cells, followed by validation in HNSCC tissues and cell lines. To define its functional significance, we performed siRNA-mediated knockdown, PGK1 overexpression, and pharmacological inhibition using the PGK1 inhibitor NG-52. We further conducted xenograft experiments to evaluate whether PGK1 inhibition suppresses tumor growth in vivo. Consistent with our single-cell analysis and validation experiments, PGK1 expression was elevated in HNSCC tumor tissues compared with adjacent normal tissues and was associated with poor clinical outcomes. Functionally, genetic knockdown or pharmacological inhibition of PGK1 suppressed HNSCC cell proliferation, reduced glycolytic activity, and induced G1 phase cell cycle arrest, whereas PGK1 overexpression enhanced cell proliferation. PGK1 inhibition increased p21 protein expression without markedly altering CDKN1A mRNA levels. Furthermore, NG-52 treatment significantly suppressed tumor growth in xenograft models without obvious body weight loss. NG-52-treated tumors showed reduced Ki67 expression and increased p21 protein levels, supporting the in vivo relevance of PGK1 inhibition in regulating tumor proliferation and p21 protein expression. Together, our findings demonstrate that PGK1 contributes to HNSCC progression by promoting glycolytic activity, cell proliferation, and cell cycle progression, accompanied by changes in p21 protein expression. These results support the biological relevance of PGK1 in HNSCC and suggest that PGK1 may represent a potential therapeutic vulnerability for further investigation.