Correlation Of NUDT1 With Prognosis And Tumor Microenvironment In Clear Cell Renal Cell Carcinoma

Objective:Clear cell renal cell carcinoma(cc RCC)is a malignant tumor with high morbidity and mortality.As a member of the nudix hydrolase superfamily,nudix hydrolase 1(NUDT1)is closely related to the occurrence and development of cancer.Our study aims to verify and analyze the expression level and prognostic value of NUDT1 in cc RCC through bioinformatics and preliminary experiments,and further explore its correlation with immune cell infiltration and immune checkpoints in the tumor microenvironment.Methods:The cc RCC expression matrix and corresponding clinical information were obtained from The Cancer Genome Atlas(TCGA)database.The TIMER and GEPIA databases were utilized for pan-cancer analysis of NUDT1 expression.We collected40 cases of cc RCC tissues and 40 cases of paracancerous tissues that were treated by surgery in our hospital for RT-q PCR and immunohistochemistry to detect and validate NUDT1 expression.R software was utilized to study the expression difference of NUDT1 in cc RCC and its relationship with clinicopathological features.Kaplan-Meier survival analysis was utilized to explore the effect of NUDT1expression level on the overall survival(OS)and progression free survival(PFS)of patients with cc RCC,and the accuracy of the results was evaluated by using the receiver operating characteristic(ROC)curve.Univariate Cox regression and multivariate Cox regression were utilized to evaluate the prognostic factors of patients with cc RCC,and a nomogram containing prognostic factors was constructed to predict the survival probability of patients.Gene ontology(GO)functional enrichment and Kyoto Encyclopedia of Genes and Genomes(KEGG)pathway enrichment were utilized to explore the function and pathway of the differentially expressed genes(DEGs)in NUDT1 high and low expression groups.Gene set enrichment analysis(GSEA)was utilized to identify the signal pathway related to NUDT1 in cc RCC.Finally,CIBERSORT algorithm were utilized to explore the relationship between NUDT1 and immune cell infiltration in cc RCC,and further study the correlation between NUDT1 and immune checkpoints.Results:1.Compared with normal tissues,NUDT1 expression is significantly increased in a variety of tumors,including bladder cancer,colon cancer,head and neck squamous cell carcinoma,kidney renal clear cell carcinoma,kidney renal papillary cell carcinoma,liver hepatocellular carcinoma,lung adenocarcinoma,lung squamous cell carcinoma,rectal adenocarcinoma,gastric cancer and uterine corpus endometrial carcinoma.2.NUDT1 was overexpressed in cc RCC(P<0.001),and the expression of NUDT1 in male patients was higher than that in female patients(P=0.0013).In addition,the expression of NUDT1 was positively correlated with the grade(P<0.001),stage(P<0.001),T(P<0.001),N(P=0.0037),M(P<0.001)stage of cc RCC patients.3.Univariate Cox regression analysis showed that NUDT1 was a poor prognostic factor of cc RCC patients(HR=1.908,95%CI:1.477-2.465,P<0.001),and multivariate Cox regression showed that NUDT1 could be an independent poor prognostic indicator to affect the prognosis of cc RCC patients(HR=1.437,95%CI:1.065-1.939,P=0.018).The ROC curve shows that the area under curve(AUC)corresponding to 1,3 and 5 years of survival is 0.671,0.650 and 0.616,respectively.4.A total of 150 coexpressed genes and 1,886 differentially expressed genes(DEGs)were identified.NUDT1 expression level was positively correlated with the expression of BCL2L12,POLR2J,PPP1R14B,SNRPD2,PSMG3 and POP7(P<0.01).On the contrary,NUDT1 expression level was negatively correlated with the expression of LIFR,PRKAA2,WDFY3,MYO6 and FBXO3(P<0.01).GO/KEGG and GSEA results showed that NUDT1 and its DEGs were involved in DNA replication and repair,regulation of cell cycle,inflammation and immune-related pathways.5.NUDT1 expression was positively linked with infiltrating levels of regulatory T cells(Treg),CD8~+T cells,follicular helper T cells(Tfh),and M0 macrophages.But negatively linked with the infiltration level of M1 macrophages,M2 macrophages,resting mast cells,resting memory CD4~+T cells,and monocytes in cc RCC.In addition,NUDT1 was positively related to immune checkpoints,such as PD-1,LAG3,CTLA4,CD-27and CD70,in cc RCC.Conclusions:1.High expression of NUDT1 was closely associated with poor prognosis in cc RCC patients,NUDT1 was able to predict the survival prognosis of cc RCC patients as an independent prognostic factor.2.NUDT1 may be a promising biomarker in cc RCC and may contribute to cc RCC development and progression through DNA replication and repair,cell cycle,inflammation and immune-related pathways.3.In cc RCC,NUDT1 is significantly correlated with the infiltration of many immune cells and related immune checkpoints expression,suggesting that NUDT1 may be a potential immunotherapeutic target.