GAPDH: Unveiling Its Impact As a Key Hypoxia-related Player in Head and Neck Squamous Cell Carcinoma Tumor Progression, Prognosis, and Therapeutic Potential

Head and neck squamous cell carcinoma (HNSCC), characterized by hypoxia patterns, ranks as the sixth most prevalent malignant tumor worldwide. Glyceraldehyde-3-phosphate dehydrogenase () plays a role in oncogenesis under hypoxic conditions in various cancers. However, its precise function in HNSCC, especially under varied hypoxic conditions, including at high altitudes, remains unclear. Elevated mRNA and protein levels in HNSCC relative to normal tissues have been demonstrated through data from The Cancer Genome Atlas (TCGA), GSE29330, and the Human Protein Atlas (<0.05). This elevation was further confirmed through experiments utilizing two HNSCC cell lines and a normal oral mucosal epithelial cell line. Additionally, data from TCGA and GSE41613 reveal a correlation between elevated expression and diminished overall and progression-free survival in patients (<0.05). Subsequent analysis identifies as an independent risk factor for HNSCC (<0.05). Using the ESTIMATE and single-sample gene set enrichment analysis (ssGSEA) algorithms, high expression was found to be associated with reduced immune scores and diminished anti-tumor cell infiltration, such as CD8+ T cells, in TCGA and GSE41613 datasets (<0.05). Analysis of single-cell RNA sequencing data from GSE139324 suggests that elevated expression hinders communication between plasmacytoid dendritic cells and mast cells (<0.05). Furthermore, in the TCGA and GSE41613 datasets, 's biological function is closely tied to hypoxia through Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), and Gene Set Variation Analysis (GSVA) analyses. Moreover, its expression is linked to one cuproptosis-related gene, five N6-methyladenosine-related genes, six immune checkpoint genes, and pivotal pathways such as and (<0.05). showed excellent predictive value in estimating the efficacy of immunotherapy and 11 anti-tumor drugs (e.g., cisplatin) (<0.05), using TIDE and pRRophetic algorithms on the TCGA and GSE41613 datasets. Under 1% O , HNSCC cells show elevated expression, leading to decreased apoptosis and increased migration, clonogenicity, invasiveness, and resistance to cisplatin (<0.05). At 5% O, these effects persisted, albeit less pronouncedly. Inhibiting reversed these effects under all oxygen concentrations (<0.05). Overall, our findings reveal as a key hypoxia-related player influencing tumor progression, prognosis, and therapeutic potential in HNSCC.