谷胱甘肽过氧化物酶家族的功能及其成员作为胶质瘤免疫治疗标志物的可能性

The function of the glutathione peroxidase family and the possibility of its members as immunotherapeutic markers for glioma

目的:探讨谷胱甘肽过氧化物酶(GPX)家族在胶质瘤发生发展中的生物学功能和预后价值。方法:利用TCGA、GTEx和CGGA等多个数据库数据分析胶质瘤中GPX各亚型基因的表达及其相关性、蛋白之间的相互作用、基因突变、GPX表达与胶质瘤患者预后的关系以及GPX7、8的基因集富集分析;GPX8与胶质瘤中免疫细胞浸润以及免疫检查点分子表达的相关性分析,胶质瘤中GPX8表达与化疗药物IC_(50)的相关性分析。采用qPCR法、WB法和免疫荧光技术检测国人胶质瘤组织和对照组织(标本收集自2022年10月20日至12月20日间在上海奉贤区中心医院神经外科手术切除的5例胶质瘤和3例严重脑外伤的病灶组织)中GPX mRNA、蛋白以及相关免疫检查点分子的表达进行验证。结果:数据库分析显示胶质瘤中GPX各亚型蛋白之间存在相互作用、基因表达水平存在相关性(P<0.05或P<0.01),胶质瘤组织中多个GPX亚型存在单核苷酸变异和拷贝数变异;不同类型胶质瘤组织的免疫细胞和肿瘤细胞中主要表达的GPX亚型有明显不同,在胶质瘤组织中GPX1、4、7、8均呈高表达(均P<0.05)且与胶质瘤患者预后不良相关(P<0.01)。qPCR法、WB法检测中国人胶质瘤组织中GPX7、8均呈高表达验证了数据库信息的正确性。在胶质瘤中GPX7、8表达具有独立预后预测价值;富集分析显示GPX7、8与胶质瘤细胞周期和免疫途径有关,在GBM和LGG中GPX8表达与免疫评分呈明显相关(P<0.01)、GPX8可能在胶质瘤中诱导抑制性免疫细胞浸润导致免疫抑制、GPX8表达与胶质瘤中多个免疫检查点分子表达正相关(均P<0.01)、GPX8表达与化疗药物IC_(50)呈明显正相关(均P<0.01)且其高表达可导致胶质瘤对化疗药物的耐药。结论:GPX8在胶质瘤中呈显著高表达,GPX8高表达能诱导胶质瘤中抑制性免疫细胞的浸润其与多个免疫抑制点、与多个化疗药物IC_(50)和患者预后密切相关,可作为胶质瘤免疫治疗的潜在靶点。

Objective:To explore the biological function and prognostic value of the glutathione peroxidase(GPX)family in gliomas.Methods:The correlation of gene expression of GPX isoforms in gliomas,protein interactions,gene mutations,the relationship between GPX expression and the prognosis of glioma patients,and the gene set enrichment analysis of GPX7 and 8 were analyzed using various databases such as TCGA,GTEx,and CGGA;the correlation analysis of the expression of GPX8 with the immune cell infiltration and the expression of immune checkpoint molecules in glioma;and the correlation analysis of GPX8 expression with IC50 of chemotherapeutic agents in glioma.The correlation between GPX8 expression and IC50 of chemotherapeutic drugs was analyzed;the expression of GPX mRNA,protein and related immune checkpoint molecules in glioma tissues and control tissues of Chinese people(Specimens were collected from five cases of glioma and three cases of severe traumatic brain injury surgically removed by neurosurgery at Fengxian District Central Hospital,Shanghai,China,between October 20,2022 and December 20,2022.)were detected by qPCR,WB and immunofluorescence techniques for validation.Results:Database analysis showed that there were interactions and correlation of gene expression levels among GPX isoforms in gliomas(P<0.05 or P<0.01),and there were single-nucleotide and copy-number variations of several GPX isoforms in glioma tissues;there were significant differences of GPX isoforms in different types of immune cells and tumor cells of glioma tissues;and high expression levels of GPX1,4,7,and 8(all P<0.05)were correlated with poor prognosis of glioma patients(P<0.01).7 and 8 were highly expressed in glioma tissues(all P<0.05),and correlated with poor prognosis of glioma patients(P<0.01);qPCR and WB assays for GPX7 and 8 expression in human glioma tissues verified the correctness of the database information;the expression of GPX7 and 8 in gliomas has an independent prognostic value;GSEA analysis showed that GPX7 and 8 are associated with the glioma cell cycle and the immune pathway;GBM and LGG are associated with GBM and LGG;and GPX7 and 8 are associated with GBM and LGG are associated with GBM and LGG.related;GPX8 expression was significantly correlated with immune scores in GBM and LGG(P<0.01);GPX8 may induce infiltration of suppressive immune cells in gliomas leading to immunosuppression;there was a positive correlation between GPX8 expression and the expression of several immune checkpoint molecules in gliomas(P<0.01);there was a significant positive correlation between GPX8 expression and the IC50 of the chemotherapeutic agents(P<0.01),and its high expression could lead to the resistance of glioma to chemotherapeutic drugs.Conclusion:GPX8 expression is significantly high in gliomas,and GPX8 expression may induce infiltration of suppressor immune cells in gliomas,which is strongly associated with multiple immunosuppression points,with the IC50 of multiple chemotherapeutic agents,and with patient prognosis,which may serve as a potential target for immunotherapy of gliomas.