Abstract / Summary
Abstract Background Metabolic reprogramming and lactate-associated microenvironmental remodeling are integral to oral squamous cell carcinoma (OSCC) progression. Phosphoenolpyruvate carboxykinase 1 (PCK1), a cytosolic cataplerotic enzyme linking tricarboxylic-acid-cycle intermediates to phosphoenolpyruvate production, has context-dependent functions across malignancies. Its biological role and relationship with lactate-related transcriptional states in OSCC remain incompletely defined. Methods A lactate-related prognostic signature was developed from TCGA-HNSC transcriptomic data using differential-expression analysis, univariable Cox regression, and LASSO-Cox modeling. PCK1 expression was evaluated by immunohistochemistry in 23 primary OSCC specimens and 15 non-malignant oral mucosal specimens. Functional effects were assessed in SCC25 and HSC3 cells using CCK-8, colony-formation, EdU-incorporation, wound-healing, and Transwell assays. A four-group SCC25-derived xenograft model (sh-PCK1, shNC, Vector, and OE-PCK1) was used to examine bidirectional PCK1 manipulation in vivo. Pathway associations were explored using GO/KEGG, GSEA/GSVA, immune-infiltration analyses, and tumor-tissue immunoblotting. Results A total of 135 differentially expressed lactate-related genes were identified; 15 were associated with prognosis, and six genes (ABCB1, AKAP12, PCK1, PDGFA, SHCBP1, and SLC20A1) were retained in the final prognostic signature. The high-risk state was associated with shorter overall survival, lower stromal/immune/ESTIMATE scores, and distinct inferred immune-cell profiles. PCK1 expression was reduced in OSCC and was associated with adverse clinicopathological features and shorter overall survival. In vitro, PCK1 overexpression consistently reduced cellular viability, clonogenicity, DNA synthesis, migration, and invasion in SCC25 and HSC3 cells. In vivo, bidirectional PCK1 manipulation produced non-linear changes in tumor burden, Ki67, TUNEL, and total PI3K abundance, indicating that the phenotypic output of PCK1 is strongly conditioned by the tumor environment. Transcriptomic enrichment and xenograft protein data converged on a functional association with PI3K/Akt-related signaling. Conclusion PCK1 is a clinically relevant metabolic regulator in OSCC that exerts a reproducible suppressive effect on malignant phenotypes in vitro while displaying context-dependent behavior in vivo. Its integration within a lactate-related transcriptional program associated with immune contexture and PI3K/Akt-related signaling identifies PCK1 as a biologically informative node linking carbon metabolism, tumor-cell behavior, and the microenvironment.