| Background Epstein-Barr virus(EBV)latent membrane protein 1(LMP1)plays critical roles in the initiation and progression in several associated carcinomas.One important effect LMP1 gene exerted was the dysregulation of microRNAs(miRNAs).These miRNAs influenced the expression level of a large number of mRNAs in multiple ways.While few researches focused on the landscape of interactions between miRNAs and mRNAs about LMP1 gene,thus to illustrate the global change induced by LMP1 may provide understanding about the functions EBV played in associated carcinomas.This study takes advantage of Integrated bioinformatic tools to explore LMP1 gene associated miRNAs and mRNAs.A protein-protein network and a miRNA-mRNA interaction network were constructed based on the analysis.The work revealed another layer of gene regulation network in the LMP1-associated gene expression axis,which may open a way to explore the potential mechanism about EBV related disease.EBV infected epithelial cells and may cause significant changes in the intra-cellular and external environment.Including the the change of the expression level of miRNAs.Increasing evidence indicated that aberrantly expressed miRNAs play crucial roles in various neoplasms by regulating multiple tumor-related target genes.The miRNA-134 has been shown to be involved in the genesis and progression of various tumors.It acted either as a tumor suppressor or an oncogene in the pathogenesis of different types of tumors.Analysis of Gene Expression Omnibus(GEO)suggesting that miR-134-5p may be involved in the pathogenesis of EBV related epithelial carcinoma.The aim of this study is to explore the role and mechanism of miR-134-5p to be involved in EBV associated gastric cancer(EBVaGC)and EBV negative gastric cancer(EBVnGC).So as to provide experimental evidence for clarifying the oncogenic mechanism of miR-134-5p in EBV related epithelial carcinoma.Methods Two LMP1-associated microarray expression profiles data(GSE29297 and GSE26596)were downloaded from the GEO database.A protein-protein interaction network was constructed by using bioinformatic platform Gene-Cloud of Biotechnology Information(GCBI).Gene expression models were constructed based on the tendency of differentially expressed genes.GEO online tool GE02R was used to explore the differentially expressed miRNAs.A map of miRNA-mRNA interaction was then constructed by using above data.qRT-PCR was used to detect the expression levels of miR-134-5p in 3 EBVaGC cell lines and 3 EBVnGC cell lines.EBVnGC cell line SGC-7901 was transfected with miR-134-5p mimics and mimics negative control.EBVaGC cell line GT39 was transfected with miR-134-5p inhibitor and inhibitor negative control.The function of miR-134-5p in cell proliferation,apoptosis,migration and invasion was assessed via CCK-8 assay,flowcytometry,wound healing assay respectively.Results ? 2802 differentially expressed genes were identified in dataset GSE29297;and for GSE26596,102 up-regulated miRNA and 6 down-regulated genes were identified.?20 expression models were established based on the five groups in dataset GSE29297,15 of which were estimated as statistical significant.Notably,a descending expression model including 1422 genes and an ascending model including 1070 genes were identified as significantly enriched,which may be affected by the LMP1 associated up-regulated miRNAs.? A co-expression network including 245 genes and 661 connections was constructed based on the differentially expressed genes.? The miRNA target mRNAs predicted by miRNA databases were compared with the ascending model and the descending model,and a miRNA-mRNA interaction network was generated.? Compared with 3 EBV positive cell lines(GT3 8,GT39 and SNU-719),the expression of miR-13-5p was up-regulated in 3 EBVaGC cell lines(SGC-7901,MKN-45 and HGC-27)with significant difference(t=6.023,P<0.001).? Compared with control cells,overexpression of miR-134-5p was induced in miR-134-5p mimics transfected cell line SGC-7901(t=13.747,P<0.001)and no significant down-regulated expression of miR-134-5p was observed in miR-134-5p inhibitor transfected cells GT39(t=-2.229,P>0.05).?Over-expression of miR-134-5p decreased the proliferation,and increase the apoptosis of SGC-7901(t=7.793,P<0.001),no significant difference was observed between the cell migration rate and the control group(t=1.107,P>0.05).While the miR-134-5p inhibitor transfected EBVaGC cell line were testified to have intensive ability in proliferation and migration rate(t=5.403,P<0.001),and the apoptosis resistance was statistically significant(t=-7.393,P<0.01).Conclusion By taking advantage of bioinformatic tools and GEO profiles,a protein-protein network and a miRNA-mRNA interaction network associated with LMP1 gene were constructed.Gene expression models were also constructed to illustrate the expression tendency.This study extended the dimension of gene regulation network in the LMP1-associated gene axis,which would provide productive understanding of the interaction of mRNAs and miRNAs.The interaction relationship may open a way to explore the potential use of miRNA in EBV-associated carcinomas.Up-regulation of miR-134-5p attenuated the proliferation and invasion and promote the apoptosis of EBVnGC line SGC-7901,while in EBVaGC,Down-regulation of miR-134-5p promoted the proliferation and invasion and attenuated the apoptosis,suggesting that miR-134-5p acts as an anti-oncogene in the pathogenesis of EBVaGC. |
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