GBP2 As A Potential Prognostic Predictor With Immune-Related Characteristics In Glioma

Background:Glioma is the most common malignant brain tumor in adults,accounting for 81%of malignant tumors in the central nervous system.Gliomas usually originate from glial cells or their precursors,and gradually develop into astrocytomas,oligodendrogliomas,ependymomas,or mixed gliomas.Gliomas have a high mortality rate,low survival rate,and high recurrence rate.According to the World Health Organization,gliomas are classified into four grades.Grade Ⅰ and Ⅱ are low-grade gliomas,with a median survival time of 11.6 years.Grade Ⅲ and Ⅳ are high-grade gliomas,with a total survival time of only 15 months to 3 years.They develop rapidly and pose a great threat to human health.Currently,the main method and strategy for treating gliomas is comprehensive treatment with surgical resection and adjuvant chemotherapy and radiation therapy.Low-grade patients may have a chance of complete recovery,while high-grade gliomas often recur and cannot be cured.This is because comprehensive treatment cannot completely eliminate glioma cells.There is an urgent need for new treatment methods,and using immune checkpoint therapy to treat gliomas has become a potential new treatment strategy after comprehensive treatment.Objective:Guanylate binding protein 2(GBP2)is a member of the guanylate binding protein family(GBPs)and can bind to guanine nucleotides(GMP,GDP,and GTP).It has been reported that GBP2 increases the invasiveness of glioblastoma through the Stat3/Fibronectin pathway.GBP2 is also associated with the prognosis of pancreatic cancer and melanoma and is involved in the progression of melanoma through the Wnt/beta-catenin pathway.Our previous studies have shown that GBP2 can regulate the growth and migration of glioma cells.However,there have been few studies on the clinical correlation and immune-related characteristics of GBP2 in gliomas.In this study,we explore the expression differences of GBP2 in gliomas and normal tissues at multiple levels,as well as analyze the diagnostic and prognostic value of GBP2 in gliomas.We also investigate the relationship between GBP2 and the immune characteristics of gliomas.Methods:Obtain glioma data from The Cancer Genome Atlas(TCGA)database,corresponding normal tissue data from University of California Santa Cruz Xena public(UCSC Xena)data platform,and glioma data from Chinese Gliomas Genome Atlas(CGGA).Process the obtained data using R software,and analyze GBP2 expression using Gene Expression Profiling and Interactive Analyses(GEPIA),Ualcan online database,and The human protein atlas database(HPA).Further analyze the correlation between GBP2 and clinical features and prognosis of glioma using R language.Single gene differential analysis combined with Gene ontology(GO),Kyoto encyclopedia of genes and genomes(KEGG),and Gene set enrichment analysis(GSEA)are used to analyze the biological processes in which GBP2 may be involved.Single cell analysis and Tumor-immune System Interactions database analysis(TISIDB)are used to evaluate the immune characteristics of GBP2 in glioma.Additionally,non-coding RNA upstream of GBP2 is predicted using databases.Subsequently,different U87 and U251 cell lines are constructed.The first group is infected with si RNA to knockdown GBP2 expression(si GBP2),while the second group is transfected with control si RNA(si Ctrl).The changes in immune microenvironment markers are analyzed to determine whether GBP2 has a regulatory effect on the immune system.Additionally,mi RNA overexpression vectors are separately constructed in U87 and U251 cell lines to investigate whether overexpression of upstream non-coding RNA can change the expression of target genes.The expression levels of immune microenvironment markers and target genes are detected using real-time PCR technology.Results:Through a combined analysis using R software and public databases,we found that GBP2 is up regulated at both m RNA and protein levels in glioma.Clinical correlation analysis revealed that high expression of GBP2 is associated with adverse clinical features and poor prognosis in glioma patients.Functional analysis showed that GBP2 is involved in immune-related processes,and single-cell analysis demonstrated that GBP2 not only regulates the immune microenvironment of glioma but also correlates with the antigen presentation ability of immune cells,which was validated in U87 and U251 cell lines.Finally,we identified has-mir-26b-5p and has-mir-335-5p as potential upstream regulators of GBP2 expression,which was also validated in U87 and U251 cell lines.Conclusion:GBP2 is associated with poor clinical prognosis of glioblastoma and has the potential to serve as a prognostic biomarker.Its role in modulating the immune microenvironment and involvement in antigen presentation suggest that GBP2 could be a potential immunotherapeutic target for glioma.Additionally,we identified has-mir-26b-5p and has-mir-335-5p as potential upstream regulatory factors of GBP2 expression.Our findings provide new insights for the treatment of glioma.