The Relationship And Mechanism Of NMUR1 With The Prognosis And Immune Infiltration Of Colon Cancer Based On Pan-cancer Analysis

Objective:Pan-cancer analysis offers a systematic comprehension of specific expression signatures and immune regulation in diverse cancer,and might provide potential biomarkers for prognosis and immunotherapy response.However,the role of Neuromedin U receptor 1(NMUR1)in pan-cancer has rarely been reported.Methods:(1)The Cancer Genome Atlas(TCGA)and Genotype-tissue Expression(GTEx)databases were used to acquire original data,which were further analyzed via R software.NMUR1 expression profiles were elucidated based on online databases including TCGA,GTEx,Human Protein Atlas(HPA),and TISIDB,NMUR1 prognostic values were analyzed by GEPIA2 and Kaplan Meier plotter databases.(2)NMUR1 Genetic mutation and epigenetic alteration analysis was conducted by c Bio Portal and UALCAN databases.(3)The correlation of NMUR1 expression level and immune infiltration in pan-cancer was detected according to various online databases,including TIMER,x Cell,CIBERSORT and R"ESTIMATE"package.(4)NMUR1 related genes function and pathway enrichment were carried out by the Gene MANIA and R“GSVA”packages.(5)Cancer SEA and TISCH single cell sequencing databases were used to analyze the underlying related pathway and immune signatures at single-cell level.(6)Finally,we collected CC clinical tissue samples and established the tissue microarray(TMA),immunohistochemistry staining was conducted to detect NMUR1expression signature and prognostic value in CC.Colon cancer cells were cultured to construct NMUR1 overexpression and knockdown models.CCK8 and wound healing assays were performed to investigate tumor-suppressive impact of NMUR1 on colon cancer cells.Results:(1)Bioinformatic analysis revealed that NMUR1expression was downregulated in most tumors and that its expression characteristic was correlated to poor prognosis in various cancer types.(2)A significant association was observed between the NMUR1expression level and gene mutation in pan-cancer and most cancer tissues had a higher level of NMUR1 promoter methylation.(3)Immuescore identified NMUR1 was correlated with immune cell infiltration,immune-related molecules expression level and different immune subtypes.(4)NMUR1co-expression networks and related pathways enrichment analysis showed NMUR1 were mostly involved in the DNA damage,cell cycle,cytokine receptor interaction,etc.(5)The single-cell sequencing database revealed that NMUR1expression level was significantly correlated with the composition and proportion of the tumor microenvironment(TME).(6)Furthermore,the experimental findings of this study confirmed the NMUR1 expression characteristics and association with the prognostic landscape in CC patients,and NMUR1 overexpression suppressed colon cancer cells’progression and invasion.Conclusions:(1)Bioinformatic analysis revealed NMUR1 is down-regulated in pan-cancer and its expression signature was correlated with poor prognosis and immune infiltration.(2)The functional status and immune characteristics of NMUR1 in CC were elevated by single-cell sequencing databases,results showed NMUR1 is mostly involved in tumor progression and invasion and NMRU1 is significantly up-regulated in CD4~+T cell、CD8~+T cell and macrophage cells.We then confirmed the expression signature,prognostic value and tumor-suppressive role of NMUR1 in CC and colon cancer cells by fundamental experiments.(3)All in all,NMUR1 might serve as a potential prognostic biomarker and a predictive factor to immunotherapy response in CC.