| Gastric cancer is one of the common malignancies worldwide.The mortality rate of gastric cancer in China is second only to lung cancer in malignancy,which seriously harms human health.Long non-coding RNAs(lncRNAs)are RNAs that are longer than 200 nucleotides in length.Their expression is regulated by the growth and development process,and has temporal and spatial specificity in different tissues and cell types.Therefore,unlike genes that encode proteins,lncRNAs show very large changes in different tissues.In recent years,the regulatory mechanism of competitive endogenous RNA(ceRNA)gene expression has been gradually confirmed by more and more research experiments.As a new mechanism of interaction between RNAs,this mechanism believes that ceRNAs can interact with miRNAs.Original reaction elements(MREs)compete for the same miRNA,which in turn regulates the expression of target gene transcripts.Studies have shown that lncRNA can be used as a kind of ceRNA that specifically binds miRNAs to regulate the expression of genes and is closely related to the occurrence and development of human diseases.This study integrates the disciplinary advantages of molecular biology and bioinformatics and aims to construct a molecular regulation network with lncRNA as the core in gastric cancer.This method provides important clues for the study of the mechanism of the development of gastric cancer,and also for other researches.Materials and methods:Level 3 RNA seq and miRNA seq data from 407 samples were extracted from the TCGA database.These included 375 cases of gastric cancer and 32 normal samples.The data obtained were processed by DEseq software to obtain differentially expressed lncRNA,miRNA,mRNA in gastric cancer.Bioinformatics prediction of target miRNAs with differentially expressed long non-coding RNAs using the miRcode database,and then using several miRNA databases to predict differentially expressed target genes for miRNA regulation and compare them with differentially expressed genes to predict miRNA targets mRNAs.Based on the results of the above bioinformatics prediction,a lncRNA-miRNA-mRNA ceRNA regulatory network was constructed,and genes from cancer-related pathways were selected to construct an lncRNA-miRNA-mRNA pathway.qRT-PCR validated the expression level of core lncRNA,miRNA and mRNA,and analyzed whether it was consistent with the trend of TCGA data analysis results.Results:In this study,24 differentially expressed lncRNAs,15 differentially expressed miRNAs,and 82 differentially expressed mRNAs were used to construct a global regulatory network of lncRNA-miRNA-mRNA.Genes in this regulatory network were enriched in pathways in cancer,Rap1 signaling pathway,PI3K-Akt signaling pathway,positive regulation of cell proliferation,angiogenesis and cancer-related GO and pathways.We choose to prove lncRNA UCA1/miRNA-143-3p/FGF1 pathway in 20 pairs of gastric cancer and adjacent tissues and multiple gastric cancer cells.After preliminary verification by qRT-PCR,the expression of long non-coding RNA UCA1 and FGF1 are significantly up-regulated in gastric cancer tissues and gastric cancer cells,and miR-143-3p is significantly down-regulated in gastric cancer tissues,There was a negative correlation between the expression of lncRNA UCA1 and miRNA-143-3p,and the positive correlation between miRNA-143-3p and FGF1 expression,consistent with the analysis results of the TCGA database. |
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