Abstract
Glioblastoma (GBM) is a primary malignant tumor characterized by high infiltration and angiogenesis in the brain parenchyma. Glioma stem cells (GSCs), a heterogeneous GBM cell type with the potential for self-renewal and differentiation to tumor cells, are responsible for the high malignancy of GBM. The purpose of the present study was to investigate the roles of significantly differentially expressed genes between GSCs and GBM cells in GBM progression. The gene profiles GSE74304 and GSE124145, containing 10 GSC samples and 12 GBM samples in total, were obtained from the Gene Expression Omnibus (GEO) database. The overlapping differentially expressed genes were identified with GEO2R tools and Venn software online. Subsequently, Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway analysis was performed on the 41 upregulated and 142 downregulated differentially expressed genes in GSCs compared with in GBM cells via the DAVID website. Protein-protein interaction and module analyses in Cytoscape with the STRING database revealed 21 hub genes that were downregulated in GSCs compared with in GBM cells. Survival analysis conducted via the GEPIA2 website revealed that low expression levels of the hub genes prolyl 4-hydroxylase subunit α2 (P4HA2), TGF-β induced, integrin subunit α3 and thrombospondin 1 were associated with significantly prolonged survival time in patients with GBM. Further experiments were performed focusing on P4HA2. Reverse transcription-quantitative PCR was used to detect P4HA2 gene expression. In agreement with the bioinformatics analysis, P4HA2 expression was higher in U87 cells than in GSCs. Cell Counting Kit-8, EdU incorporation, cell cycle analysis, wound healing and Transwell assays demonstrated that the cell proliferation and migration increased after P4HA2 overexpression and decreased after P4HA2-knockdown. In conclusion, the present study demonstrated that low P4HA2 expression in GSCs promoted GBM cell proliferation and migration, suggesting that P4HA2 may act as a switch in the transition from GSCs to GBM cells.