CHI3L2在脑胶质瘤中的表达和生物学过程及其对患者临床预后的影响

Expression and biological processes of CHI3L2 in brain glioma and its impact on patient prognosis

目的:基于生物信息学方法探究几丁质酶-3样蛋白2(CHI3L2)在脑胶质瘤中的表达和生物学过程及其对患者临床预后的影响。方法:以中国脑胶质瘤基因组图谱(CGGA)为训练集(n=325)、癌症基因组图谱(TCGA)为验证集(n=702),对CHI3L2与脑胶质瘤患者临床病理特征的关系、预后价值和生物学过程进行交叉验证分析。用Kaplan-Meier法进行生存分析,采用Cox回归模型分析CHI3L2表达及相关临床病理特征与脑胶质瘤患者预后的关系,利用受试者工作特征(ROC)曲线分析CHI3L2在脑胶质瘤诊断中的价值,用GO、KEGG及GSVA途径分析CHI3L2在脑胶质瘤中的潜在生物学过程,构建CHI3L2的列线图以校准曲线及C-Index值来评估预测的准确性。WB法和qPCR法检测CHI3L2在正常星形胶质细胞HA1800、胶质瘤U215和U87细胞中蛋白质与mRNA水平表达的影响。选取长沙市中心医院病理科保存的7例正常脑组织、5例低级别胶质瘤(LGG,WHOⅠ~Ⅱ级)和6例胶质母细胞瘤(GBM,WHOⅣ级)标本进行免疫组化染色分析,验证CHI3L2在正常脑组织和不同级别脑胶质瘤组织中的表达情况。结果:CHI3L2在GBM(P<0.0001)、非1p/19q编码(P<0.0001)、IDH-野生型(P<0.0001)、非MGMT甲基化(P<0.01)患者中显著表达,对GBM具有一定的预测价值,并且是脑胶质瘤患者总生存期(OS)的独立预后因素(P<0.001)。构建的列线图对脑胶质瘤患者的生存预后预测性良好。CHI3L2与LGG和GBM的免疫细胞浸润水平、肿瘤免疫微环境和免疫细胞均有显著关系。脑胶质瘤中CHI3L2蛋白(P<0.05)和mRNA(P<0.0001)的表达水平与更高的恶性程度相关,免疫组化的结果进一步验证了这个发现。结论:CHI3L2的表达与脑胶质瘤的恶性程度、临床病理特征及预后关系密切,并且参与脑胶质瘤的肿瘤微环境和免疫浸润,有望成为脑胶质瘤治疗策略中的一个新靶点。

Objective:To investigate the expression and biological processes of chitinase-3-like protein 2(CHI3L2)in brain gliomas and its impact on clinical prognosis of patients based on bioinformatics methods.Methods:With Chinese Glioma Genome Atlas(CGGA)serving as the training set(n=325)and The Cancer Genome Atlas(TCGA)as the validation set(n=702),the relationship between CHI3L2 and clinicopathologic features of brain glioma patients,as well as its prognostic value and biological processes were analyzed and cross-validated.Kaplan-Meier method was used for survival analysis.Cox regression model was employed to analyze the association between CHI3L2 expression and relevant clinicopathological features as well as prognosis of brain glioma patients.Receiver operating characteristic(ROC)curve analysis was performed to evaluate the diagnostic value of CHI3L2 for brain glioma.Gene Ontology(GO),Kyoto Encyclopedia of Genes and Genomes(KEGG),and Sene Set Variation Analysis(GSEA)were conducted to assess the potential biological processes associated with CHI3L2 in brain glioma.A Nomogram incorporating CHI3L2 and other relevant factors was constructed,and calibration curve and C-Index value were used to evaluate the Nomogram’s accuracy in prognosis prediction.The protein and mRNA expression levels of CHI3L2 in normal astrocyte HA1800,as well as glioma U215 and U87 cells,were assessed using Western blotting and qPCR,respectively.Immunohistochemistry was performed on 7 normal brain samples,5 low-grade glioma samples(LGG,WHOⅠ-Ⅱ),and 6 glioblastoma sample(GBM,WHOⅣ)that collected from the Department of Pathology at Changsha Central Hospital,with an aim to verify the expression of CHI3L2 in normal brain tissues and glioma tissues of different grades.Results:CHI3L2 was highly expressed in patients with GBM(P<0.0001),non-1p/19q coding glioma(P<0.0001),IDH-wild type glioma(P<0.0001),and non-MGMT methylation glioma(P<0.01),showing certain predictive value for GBM.Additionally,CHI3L2 was identified as an independent prognostic factor for overall survival(OS)in glioma patients(P<0.001).The constructed nomogram exhibited good predictive accuracy for patient prognosis.Furthermore,CHI3L2 was significantly associated with immune cell infiltration level,tumor immune microenvironment,and immune cells in LGG and GBM.Elevated CHI3L2 protein(P<0.05)and mRNA(P<0.0001)levels in gliomas were correlated with higher malignant grade,as further confirmed by immunohistochemistry results.Conclusion:CHI3L2 expression is intricately associated with the malignancy,clinicopathological characteristics,and prognosis of brain glioma.It actively participates in the tumor microenvironment and immune infiltration within glioma,thereby representing a promising therapeutic target for glioma treatment.