Pan-cancer investigation regarding the prognostic predictive and immunological regulation functions of PGK1 and experimental validation in esophageal squamous cell carcinoma

Phosphoglycerate kinase 1 (PGK1), a pivotal enzyme in the glycolysis pathway, contributes to tumor progression through diverse biological activities like cell metabolism, angiogenesis, proliferation, and epithelial-mesenchymal transformation (EMT). Although PGK1 has been intensively researched in specific cancer types, its overarching significance in pan-cancer contexts remains underexplored. This study leveraged various public database resources, including the Cancer Genome Atlas (TCGA), Genotype-Tissue Expression (GTEx), Tumor Immune Estimation Resource (TIMER2.0), and cBioPortal, to analyze the gene expression, gene alteration characteristics, prognostic value, subcellular localization, biological function, immune characteristics, and drug sensitivity of PGK1 in 33 different cancer types. R software was used to visualize these data. Furthermore, the effects of PGK1 on the proliferation, apoptosis, migration, and invasion of esophageal squamous cell carcinoma (ESCC) cells were also examined in vitro using 5-ethynyl-2′-deoxyuridine (EdU) incorporation assay, CCK-8 assay, Annexin V-FITC/PI assay, migration assay, and invasion assay. The findings suggested that PGK1 is upregulated in various cancer types and closely associated with poor prognosis. In terms of functional enrichment analysis, PGK1 primarily plays a role in glycolysis, hypoxia, EMT, and immune-related pathways. Furthermore, PGK1 is highly expressed in immune and malignant cells in the tumor microenvironment. Notably, PGK1 expression varied significantly among immune cells with distinct activation states. The results of experiments in vitro showed that PGK1 was significantly upregulated in ESCC cells, and its knockdown led to significant inhibition of proliferation, migration, and invasion while increasing cell apoptosis; conversely, overexpression promoted proliferation, migration, and invasion while reducing apoptosis. PGK1 can serve as a prognostic biomarker and therapy target for various cancers, and it may be a promising focal point of immunological studies.