Correlation of GPC6 expression level in gliomas with prognosis of patients and effect of GPC6 on proliferation of glioma cells in vitro
10.3760/cma.j.cn115355-20240423-00200
- VernacularTitle:胶质瘤GPC6表达水平与患者预后的关系以及体外GPC6对胶质瘤细胞增殖的影响
- Author:
Bing YAN
1
;
Kun ZHANG
;
Xinyi XU
;
Hua LIU
Author Information
1. 山东第一医科大学附属中心医院普通外科，济南 250013
- Publication Type:Journal Article
- Keywords:
Glioma;
Glypicans;
Tissue array analysis;
Prognosis;
Immunohistochemistry;
Cell proliferation
- From:
Cancer Research and Clinic
2025;37(3):198-205
- CountryChina
- Language:Chinese
-
Abstract:
Objective:To investigate the correlation between the expression level of glypican-6 (GPC6) in gliomas and the prognosis of patients, as well as the effect of GPC6 on the proliferation of glioma cells in vitro.Methods:The transcriptome sequencing (RNA-seq) data of GPC6 gene and clinical data of glioma patients were downloaded from The Cancer Genome Atlas (TCGA) database. A total of 667 patients were enrolled, and the median FPKM value of GPC6 RNA-seq was used to distinguish the low and high expression of GPC6 gene. Kaplan-Meier method was used to analyze the overall survival (OS) of GPC6 high and low expression groups in 664 patients with survival data, and log-rank test was used for inter group comparison. The postoperative tumor tissue chips were retrospectively collected from glioma patients who underwent surgery from February 2008 to October 2011, immunohistochemistry (IHC) was used to detect the expression of GPC6 protein in 147 samples, and semi-quantitative scoring ≥ 4 points or not was used to distinguish the high and low expression of GPC6 protein based on the proportion of positive cells and staining intensity. The distributions of patients with high and low expression of GPC6 protein in tumor tissues were compared between different clinical pathological features in 147 patients, and Kaplan-Meier method was used to analyze the overall survival and disease-free survival (DFS) of patients in the GPC6 protein high and low expression groups; the risk factors that affect poor OS and DFS in patients were analyzed using univariate and multivariate Cox proportional hazards models. The human glioma U251 cells were infected with lentivirus packaged with GPC6 small interfering RNA and lentivirus packaged with unrelated control sequences, namely ShGPC6 group and ShCtrl group, respectively; green fluorescent cells were counted daily and the cell proliferation fold was calculated for 5 days, and the cell proliferation curve was plotted.Results:In TCGA database, the median FPKM value of 667 glioma patients was 225.66. The median FPKM value of GPC6 gene in 515 World Health Organization (WHO) classification low-grade glioma patients was lower than that in 152 high-grade glioma patients (201.10 vs. 347.92), and the difference was statistically significant ( Z = 5.36, P < 0.001); the OS of patients in GPC6 low expression group (332 cases) was better than that in GPC6 high expression group (332 cases), and the difference was statistically significant ( P < 0.001). IHC staining of the tissue chip showed that GPC6 protein was mainly expressed in the cytoplasm and nucleus of glioma cells; high expression of GPC6 protein accounted for 31.3% (46/147) of patients. Among patients who died, relapsed, had high grading, had survival time ≤ 84 months, and had positive epidermal growth factor receptor, the proportion of patients with GPC6 protein high expression was relatively higher, and the differences were statistically significant (all P < 0.05). There were no statistically significant differences in the proportions of GPC6 protein high expression patients among patients with different genders, age ≤ 43 years old, Ki-67 positivity, and programmed death receptor ligand 1 positivity (all P > 0.05); compared to the GPC6 low expression group (101 cases), the GPC6 protein high expression group (46 cases) had worse overall survival (median OS time: 57.0 months vs. not reached) and DFS (median DFS time: 33.0 months vs. not reached), and the differences were statistically significant (both P < 0.001). Multivariate Cox regression analysis showed that high expression of GPC6 protein (high expression vs. low expression, HR = 1.86, 95% CI: 1.04-3.31, P = 0.036) was the independent risk factor for poor OS in glioma patients, but the expression level of GPC6 protein was not the independent influencing factor for DFS (high expression vs. low expression, HR = 1.55, 95% CI: 0.95-2.53, P = 0.077). After infecting U251 cells with recombinant lentivirus for 3 days, reverse transcription polymerase chain reaction detection showed that the relative expression level of GPC6 mRNA in the ShGPC6 group was lower than that in the ShCtrl group, and the difference was statistically significant ( P < 0.001), the knockdown efficiency of GPC6 reached 79.32%; under the fluorescence microscope, the number and intensity of fluorescence positive U251 cells in the ShCtrl group increased day by day after infection with recombinant lentivirus, while there was no significant change in the ShGPC6 group; starting from the second day, the proliferation rate of U251 cells in the ShCtrl group was higher than that in the ShGPC6 group, and the differences were statistically significant (all P < 0.01). Conclusions:High GPC6 expression level may associate with the high risk of death in glioma patients, and high GPC6 expression may promote the proliferation of glioma cells.
