Expression of inflammatory related gene THY1 in gastric cancer and its relationship with tumor immunity and epithelial-mesenchymal transition
Objective To investigate the expression and prognostic value of inflammatory gene THY1 in gastric cancer,and the relationship between THY1 and tumor immunity,epithelial-mesenchymal transition(EMT)based on bioinformatics analysis.Methods Data sets of gastric cancer and normal tis-sues were generated from the cancer genome atlas(TCGA)database,and inflammation-related genes that were differentially expressed in gastric cancer were screened.The differentially expressed genes(DEGs)were identified by wilcoxon.test method,and after correction,genes with P＜0.05 and expression change over 1.5 times were identified as DEGs,then THY1 was identified for subsequent study.Survival analysis function of R software package was used to determine the prognostic value of THY1 expression.Function of THY1 was enriched by Metascape database.The correlation between the expression of THY1 gene and the abundance of immune cells was investigated in TIMER 2.0 database.Proteins interacting with THY1 were analyzed using STRING database,and the protein-protein interaction(PPI)results were analyzed.The mRNA levels of each gene were detected by fluorescence real-time quantitative reverse transcription poly-merase chain reaction(RT-qPCR)in 20 cases of fresh gastric cancer tissues and adjacent tissues.The net-work data were analyzed using R software for bioinformatics.The RT-qPCR detection results of tissues were processed by SPSS 25.0 software,t-test of paired samples was used,and P＜0.05 was considered statisti-cally significant.Results Among the 162 inflammation-related genes,30 were up-regulated in gastric cancer tissues compared to adjacent tissues,and 32 were down-regulated(P＜0.05),and THY1 was de-termined as the research object.The expression of THY1 in gastric cancer tissues(18.60±1.16)was sig-nificantly higher than that in normal tissues(16.98±1.31,W=10 017,P＜0.01).According to the me-dian of THY1,patients were divided into high expression group and low expression group.Kaplan-Meier survival results showed that the median survival time in the high expression group was significantly shorter than that in the low expression group(x2=5.62,P＜0.05).The results of functional enrichment analysis of THY1 gene showed that its function was related to Ephrin receptor signaling pathway,positive regulation of cell adhesion,regulation of leukocyte mediated cytotoxicity,etc.The expression of THY1 was positively correlated with the infiltration of CD4+and CD8+T cells.The samples were grouped according to the me-dian of THY1 level,and DEGs were identified via wilcoxon.test,and then GSEA enrichment analysis was carried out.The results showed that DEGs were enriched in EMT process and inflammatory response.PPI results showed that THY1 protein interacted with fibronectin 1(FN1),erythropoietin-producing hepatocyte receptor A4(EPHA4)and other proteins.Results of clinical tissue detection showed that the mRNA ex-pression levels of THY1,FN1,ARHGAP5,and EPHA4 in gastric cancer tissues(4.668±3.449,8.382±2.093,1.647±0.294)were higher than those in adjacent tissues(1.005±0.398,1.026± 0.131,0.759±0.125),and the difference was statistically significant(t=4.718,3.508,2.786,P＜0.01).Conclusion THY1 gene may participate in immune response and EMT process to promote the progression of gastric cancer,and is a new potential target gene for the treatment of gastric cancer.
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