Biological Information Analysis Of A Panel Of Collagen Genes Associated With Prognosis Of Patients With Gastric Cancer And Regulated By MicroRNA-29c-3p

Objective:To screen the differentially expressed genes(DEGs)of gastric cancer(GC)via bioinformatics method,and to explore the clinical significance and regulatory mechanism of these genes.The aim of the present study was to identify potential markers of diagnostic,treatment and prognostic of GC.Methods:1)Download the Gene data with clinical information of GC patients from GEO(Gene Expression Omnibus)database.To analyze the data sets obtained from GEO with R language.The genes with significantly high or low expression in GC patients was extracted and obtained the intersection of DEG.The potential role of DEG was determined through GO(Gene Ontology analysis)functional annotation and KEGG(Kyoto Encyclopedia of Genes and Genomes)pathway enrichment analysis.Subsequently,the protein-protein interaction(PPI)network analysis of DGEs was performed to further screen target genes.The association of target genes involved in the prognosis of GC patients was determined using data provided by the Kaplan-Meier-plotter database,the Cancer Genome Atlas Stomach Adenocarcinoma(TCGA-STAD),and a GC-related dataset(GSE15459).2)The expression and clinical significance of target genes in GC tissues and non-cancer tissues were validated by real-time quantitative fluorescence PCR(RT-qPCR),immunohistochemistry(IHC),COX analysis,and ROC analysis in our in-housecohort.3)miRNA able to target the identified candidate genes were predicted and confirmed using RT-qPCR,Western blotting,and dual-luciferase reporter assays in vitro.Results:Four differentially gene expression sets(GSE13861?GSE27342?GSE54129?GSE63089)of GC were obtained from GEO database,and 76 DEGs including 34 up-regulated genes and 42 down-regulated genes were selected.GO and KEGG pathway analysis indicated that these genes were significantly enriched in extracellular matrix(ECM)-related functions and pathways.Through PPI network analysis,a group of collagen genes(COL10A1,COL1A1,COL1A2,COL3A1,COL4A1,COL5A2,and COL6A3)were found to be significantly up-regulated in the GC tissue and constitute important nodes of the PPI network.Overexpression of COL1A1 and COL4A1 was confirmed in GC tissues,and this was closely related to prognosis and certain clinicopathological parameters.Double luciferase reporter assay found that miRNA-29c-3p could directly target COL1A1 and COL4A1.Conclusion:A group of collagen genes identified in this study are high expressed in GC patients.The high expression of COL1A1 and COL4A1 is related to poor prognosis of GC patients,which may serve as GC diagnostic markers or potential therapeutic targets.Abnormal expression of COL1A1 and COL4A1 in GC patients might be regulated by miRNA-29c-3p.