关键词: CD44, 胶质母细胞瘤, 泛癌, 细胞功能, 生物信息学

Abstract: Objective To investigate the clinical significance of the differential expression of CD44 in glioblastoma (GBM), and the enrichment of related pathways combined with U87 cell verification. Methods Differential expression and Cox analysis were used to find potential differences in CD44 expression between tumor patients and healthy people as shown by pancancer transcriptome and hazard ratio (HR). Immunoinfiltration and stem-cell related scores of GBM patients with high and low CD44 expression groups were compared and the differences between immune cell subsets, and their correlation with CD44 were further analyzed. Pathway enrichment of differentially expressed genes in high and low CD44 expression groups for GBM patients was performed. Over-expression (OE), knockdown (KD) and knockout (KO) of CD44 in U87 cells was done by constructing and packaging lentivirus and using the electroribonucleoprotein complex; CD44 immunofluorescence staining was performed on U87 and U87 CD44 OE cells. The activity and apoptosis of U87 cells were detected by knocking down CD44 and the migration and invasion ability of U87 cells were detected by knocking down CD44. Results The expression of CD44 in GBM patients was higher than that in healthy people (P＜0.05) and HR＞1. GBM patients with high CD44 expression had higher stromal cell and immunoinfiltration scores, and GBM patients with high and low CD44 expression had significant differences in the ratio of dendritic cells, CD4⁺ memory T cells and regulatory T cells, all positively correlated with CD44 expression (P＜0.05). Differential gene enrichment in GBM patients with high and low CD44 expression was further associated with pathways related to cell migration and apoptosis(P＜0.05). Experiments using U87 cells showed that CD44 was normally localized in the cell membrane, but for CD44 OE it accumulated in the cytoplasm. CD44 KD can lead to a decrease in cell viability, increased in cell apoptosis, with the cell migration and invasion ability of CD44 KO also decreasing (P＜0.05). Conclusions Low expression of CD44 can decrease viability, migration and invasion of U87 cells and promote apoptosis rate of U87 cells, which leads to the deterioration of GBM and is a related factor potentially affecting the prognosis of GBM patients.

Key words: CD44, glioblastoma, pancancers, cell function, bioinformatics