Potential regulatory mechanism of overexpression of phosphatidylinositol glycan anchor biosynthesis class U on the glycolytic pathway in hepatocellular carcinoma

OBJECTIVE: To explore the potential molecular regulatory mechanisms of phosphatidylinositol glycan anchor biosynthesis class U (PIGU) in glycolysis in hepatocellular carcinoma (HCC). METHODS: This study initially employed public databases of global bulk RNA (including multi-center microarray and bulk RNA sequencing), in-house immunohistochemistry (IHC), proteomics, and single-cell RNA sequencing (scRNA-seq) to detect the comprehensive overexpression of PIGU in HCC. Combined with CRISPR knockout screen analysis, the impact of knocking out PIGU on HCC cell lines was assessed. bulk RNA and scRNA-seq data were utilized to identify the potential regulatory mechanisms of PIGU in HCC. Further analysis of PIGU's potential regulatory modes in glycolysis was conducted using scMetabolism and scFEA. CellChat was used to explore the pathways of PIGU in various cell types. In vitro experiments were conducted to reveal the biological effects of PIGU on SMMC-7721 and Huh7 cells through proliferation, migration, invasion, cell cycle, and apoptosis assays. RESULTS: PIGU was markedly overexpressed in bulk RNA (3773 HCC samples), IHC and proteomics (234 HCC samples), and scRNA-seq (22861 HCC cells). CRISPR knockout of PIGU inhibited the proliferation of HCC cell lines. The upregulation of PIGU modulated glycolysis and affected the cell cycle, promoting the glycolytic metabolic pathway from Glucose to G6P and 3PD to Pyruvate. Additionally, high expression of PIGU potentially regulated the MK pathway. In cell experiments, knockdown of PIGU gene expression impeded the proliferation, migration, and invasive capabilities of SMMC-7721 and Huh7 cells, and induced a tendency towards cell cycle arrest and apoptosis in SMMC-7721 cells. CONCLUSIONS: Overexpression of PIGU may potentially promote glycolysis by regulating the conversion from Glucose to G6P and from 3PD to Pyruvate, affecting the cell cycle, and thereby promoting the occurrence and development of HCC.