Analysis Of The Expression And Significance Of DARS2 Gene In Bladder Cancer And Pan-cancer Based On Bioinformatics

Objective: DARS2 is a gene encoding aspartyl-tRNA synthetase(AspRS),which not only has the classical function of catalyzing protein biosynthesis,but also has been shown to play a role in the development of some tumors(hepatocellular carcinoma,lung adenocarcinoma)with more in-depth studies in recent years.However,current knowledge of the role of DARS2 in Bladder Urothelial Carcinoma(BLCA)is limited.Therefore,this study will use bioinformatics techniques based on several databases to initially explore DARS2 expression in BLCA patients and analyze its correlation with multiple clinical variables and prognosis.Exploring the potential regulatory mechanism of DARS2 in BLCA development by single gene set enrichment analysis(GSEA).To analyze the correlation between the expression of DARS2 in BLCA and the tumor immune microenvironment,and to further evaluate the expression of DARS2 in pan-cancer and its correlation with clinical stage and prognosis.Methods: This study focuses on bioinformatics analysis of BLCA data from The Cancer Genome Atlas(TCGA)database and GSE7476 dataset from Gene Expression Omnibus(GEO)database using R language and various online sites including GEPIA2,TIMER,c Bio Portal,COSMIC.First,the complete data of TCGA-BLCA and GSE7476 datasets were initially filtered and screened using R language;then,the differential expression of DARS2 in TCGA-BLCA and GSE7476 datasets was analyzed by R language and validated using GEPIA2 database.To analyze the correlation between DARS2 and different clinicopathological characteristics such as TNM stage,pathological grade,gender,age,and race and to assess the degree of relationship between DARS2 and each clinical variable using single gene logistic regression analysis.Diagnostic ROC curves were plotted and the ability of the variable DARS2 to differentiate between bladder uroepithelial carcinoma tissue and normal bladder tissue was analyzed according to the area under the curve(AUC)and the optimal threshold was determined.The role of DARS2 expression in prognosis was assessed using Cox survival regression analysis,and variables that were statistically significant in univariate Cox regression were further included in multivariate Cox regression.Evaluation of mutation frequency and mutation type of DARS2 in BLCA in c Bio Portal and COSMIC databases.To investigate the potential mechanism,BLCA samples were divided into high and low expression groups according to the expression value of DARS2 gene(simulating the effect of similar overexpression or knockdown of the gene),and the differential molecules in the two groups were analyzed to obtain the molecules that might be associated with DARS2 and then GSEA analysis was performed and visualized.Analysis of DARS2 correlation with BLCA immune microenvironment based on ss GSEA algorithm and validation using TIMER database to reveal its potential as an immunotherapeutic target.Finally,the genomic data of 33 cancer types including BLCA and the corresponding clinical data were downloaded from UCSC Xena database and visualized by using R language,GEPIA2 and TIMER database to analyze the expression of DARS2 in pan-cancer and its correlation with prognosis and clinical stage.Results: DARS2 gene was significantly higher expressed in BLCA tissues compared with normal bladder tissues,and the increased expression level of DARS2 was significantly correlated with different races,T-stage,M-stage,clinical stage,pathological histological grade,primary treatment outcome,overall survival,disease-specific survival,and tumor status.Diagnostic ROC curves showed some accuracy in the predictive power of the variable DARS2 in predicting BLCA outcomes(AUC = 0.868,CI = 0.798-0.937),with an optimal diagnostic threshold of 4.065 and high sensitivity(84.2%)and specificity(81.1%).Cox survival regression analysis showed that high expression of DARS2 was significantly associated with poor prognosis(lower OS,DSS,and PFI)in patients with BLCA.Multivariate Cox regression risk models showed that DARS2 expression level was an independent prognostic factor in BLCA patients.Single-gene GSEA analysis suggests that DARS2 may act through pathways affecting the cell cycle checkpoint,cell cycle,mitotic spindle checkpoint,M phase,and DNA replication in BLCA patients.The results based on ss GSEA analysis showed that DARS2 expression levels significantly correlated with the infiltration levels of multiple immune cells.Finally,further analysis in the pan-cancer data showed that the expression of DARS2 differed significantly between multiple tumor tissues and normal tissues,and that its expression was strongly correlated with the clinical stage and prognosis of multiple tumors.Conclusion: The findings suggest that increased levels of DARS2 expression significantly correlate with BLCA progression,potentially promoting BLCA progression by promoting the tumor cell cycle and altering the tumor immune microenvironment,and could be used as a new prognostic biomarker for BLCA patients,and could potentially be promoted in a variety of tumors.