囊泡胺转运蛋白1表达与胶质母细胞瘤免疫微环境的相关性研究

A correlational study of vesicle amine transport protein 1 expression and the immune microenviron-ment in glioblastomas

目的探讨囊泡胺转运蛋白1(VAT1)的表达与胶质母细胞瘤(GBM)免疫微环境的相关性。方法回顾性分析中国脑胶质瘤基因图谱(CGGA)计划数据库中135例GBM患者的临床资料及转录组数据。采用CIBERSORT反卷积算法分析135例肿瘤组织中不同免疫细胞的占比。根据VAT1基因表达量的中位数分为高表达组(基因表达量大于或等于中位数;n=68)和低表达组(基因表达量小于中位数;n=67)。对两组间的差异基因进行基因富集分析(GSEA)。随机选取2018年11月至2019年4月首都医科大学附属北京天坛医院神经外科行开颅肿瘤切除术治疗的9例GBM患者的肿瘤组织样本,应用免疫组织化学染色技术检测VAT1、p65及CD80蛋白表达情况,并采用半定量方法判断蛋白染色结果。结果免疫细胞浸润分析结果显示,与VAT1低表达组比较,VAT1高表达组的滤泡辅助性T细胞和活化自然杀伤细胞占比均低,差异均具有统计学意义(P=0.019和P=0.045)。GSEA分析结果显示,与VAT1高表达呈正相关的基因功能主要富集在免疫系统过程、免疫反应调节和炎性反应(均P<0.001),且VAT1高表达与核因子κB(NF-κB)抑制物(IκB)激酶/NF-κB信号的调控和IκB激酶/NF-κB信号的正向调控密切相关(均P=0.001)。随着VAT1表达量的升高,多种NF-κB信号通路特异性基因表达呈正相关趋势(均P<0.001)。9例GBM的免疫组织化学染色结果显示,p65蛋白和CD80蛋白均与VAT1蛋白表达呈正相关(r值分别为0.92和0.93,均P=0.004)。结论初步研究发现,GBM患者中VAT1高表达可能会影响肿瘤免疫反应,并可能通过调控NF-κB信号通路影响肿瘤免疫细胞的浸润。

Objective To explore the correlation between vesicle amine transport protein 1(VAT1)expression and the immune microenvironment of glioblastomas(GBMs).Methods The clinical data and transcriptome data of 135 GBM patients in the Chinese Brain Glioma Genome Atlas(CGGA)dataset were retrospectively analyzed.The algorithm CIBERSORT was used to analyze the proportion of various immune cells in 135 tumor tissues.According to the median value of VAT1 gene expression,it was divided into a high expression group(gene expression level greater than or equal to the median;n=68)and a low expression group(gene expression level less than the median;n=67).The gene set enrichment analysis(GSEA)was performed on the differentially expressed genes between the two groups.Tumor tissue samples from 9 GBM patients who underwent craniotomy and tumor resection at the Department of Neurosurgery,Beijing Tiantan Hospital,Capital Medical University from November 2018 to April 2019 were randomly selected,and immunohistochemical staining was used to detect the expression of protein VAT1,p65 and CD80 proteins.The staining results were evaluated by semi-quantitative method.Results According to the CIBERSORT analysis,the infiltration of follicular helper T cells and natural killer cells in VAT1 high expression group declined compared with VAT1 low expression group(P=0.019 and P=0.045,respectively).The result of GSEA analysis indicated that VAT1 expression was functionally involved in the immune process,regulation of immune response and inflammatory response(all P<0.001).High expression of VAT1 was closely related to the regulation of nuclear factor kappa B inhibitor(IκB)kinase/nuclear factor kappa B(NF-κB)signaling and the upregulation of IκB kinase/NF-κB signaling(both P=0.001).With increased expression of VAT1,multiple specific genes of NF-κB signaling pathway showed positive correlation(all P<0.001).The result of immunohistochemical staining from 9 GBM patients indicated that the expression levels of p65 and CD80 were positively correlated with VAT1(r=0.92 and 0.93 respectively,both P=0.004).Conclusion The preliminary study suggests that high expression of VAT1 could affect the immune response in GBMs and might alter the infiltration of peritumor immune cells via regulating NF-κB signaling pathway.