Integrative Bioinformatics Analysis Identified Hub Genes in Association with Development of Lung Adenocarcinoma
Abstract Background: Cancer-related death is mainly caused by lung adenocarcinoma (LUAD), an aggressive malignant tumor. Therefore, the identification of important LUAD-related genes and the further analysis of its prognostic significance are critical for the survival of LUAD patients.Methods: Weighted Gene Co-expression Network Analysis (WGCNA) and differential gene expression analysis methods were adopted to screen out TCGA-LUAD database and the gene expression profiles of GSE32863 from GEO. Functional annotation analysis and protein-protein interaction (PPI) network were conducted on differential co-expression genes. Furthermore, survival analysis was carried out on twelve hub genes that were identified by applying the CytoHubba plugin of Cytoscape. Finally, we validated the protein level of survival-related gene in HPA database.Results: A total of 358 differential co-expression genes were extracted from the database of TCGA and GEO. These genes were mainly enriched in extracellular structure organization, cell−substrate adhesion and response to acid chemical (biological process), cell−cell junction and collagen−containing extracellular matrix (cellular component), DNA−binding transcription activator activity, glycosaminoglycan binding, and growth factor binding (molecular function). In the KEGG analysis, the main pathways were Drug metabolism−cytochrome P450. Moreover, in a PPI network, the 12 hub genes (GNG11, ADRB2, ADCY4, TGFBR2, IL6, GPC3, VIPR1, GRK5, CAV1, RAMP3, RAMP2, and CALCRL) were identified. The expression level of ADCY4, VIPR1, and TGFBR2 was corresponded with clinical stages and overall survival (OS) in LUAD patients. Finally, the protein level of ADCY4 and VIPR1 was down-regulated consistently with mRNA levels in LUAD samples.Conclusion: Perhaps, ADCY4, VIPR1 and TGFBR2 play important role in tumorigenesis, so they will serve as prognostic biomarkers and therapeutic targets of LUAD in the future.