LncRNA SMARCC2-miR-551b-3p-TMPRSS4 Axis Is Involved In Cell Proliferation,Migration And Invasion In Gastric Cancer

ObjectiveMicroRNA microarray show miR-551b-3p is decreased in gastric cancer tissues,however,its role and mechanism in gastric cancer is poorly understood.The current study focus on miR-551b-3p,aims to understand role of miR-551b-3p in gastric cancer and position of miR-551b-3p in the molecular regulation network of gastric cancer.Methods1.Real-time quantitative PCR was used to determine miR-551b-3p expression in gastric cancer cell lines and normal gastric epithelial cell line,different expression miR-551b-3p in gastric cancer tissues and matched adjacent tissues,analysis was performed to compare the correlation between different expression miR-551b-3p and clinicopathological characteristic of the patients.2.Transient transfection and lentivirus infection were used to establish gastric cancer cell models with miR-551b-3p overexpression.Cell growth curve,colony formation,determination of cell apoptosis,wound healing,transwell miagration and invassion assay,nude mice xenograft assay were used to analysis how miR-551b-3p overexpression impact on the proliferation,migration and invasion of gastric cancer cells.3.RNA-seq and bioinformatic methods were used to screen target gene of miR-551b-3p,bioinformatic methods were used to predict upstream lncRNA of miR-551b-3p.Dual luciferase reporter gene assay was used to validate interaction between miR-551b-3p and its target gene,upstream lncRNA and miR-551b-3p.Western blot was used to determine changes in the expression of target gene after upregulation of miR-551b-3p.Real-time quantitative PCR was used to determine expression of the upstream lncRNA in gastric cancer cells,changes in the expression of miR-551b-3p after alteration of upstream lncRNA,cell growth curve,transwell miagration were used to analysis how the upstream lncRNA impact on the proliferation,migration of gastric cancer cells.Western blot was used to determine affection on the expression of target gene by the upstream lncRNA.Results1.Expression of miR-551b-3p in five gastric cancer cell lines were lower than in normal gastric epithelial cell.Compared to normal gastric tissues,expression of miR-551b-3p was decreased in gastric cancer tissues,levels of miR-551b-3p were positively correlated with tumor differentiation,negatively correlated with depth of invasion and lymphatic metastasis.Survival analysis showed that tumors with higher expression level of miR-551b-3p have a better prognosis compared to lower ones.2.The vitro experiments revealed that upregulation of miR-551b-3p in gastric cancer cells inhibits cell proliferation,inhibits colony formation,promote cell apoptosis,inhibits cell migration and invasion.Nude mice xenograft assays revealed that mi R-551b-3p can inhibit vivo growth of gastric cancer cells.3.We got TMPRSS4 as potential gene target of miR-551b-3p from RNA-seq and bioinformatic methods,and lncRNA SMARCC2 as potential upstream lncRNA from bioinformatic methods.Dual luciferase reporter gene assay validate miR-551b-3p directly binds the 3'untranslated region of TMPRSS4,lncRNA SMARCC2 directly binds miR-551b-3p with its miRNA response elements.Upregulation of miR-551b-3p can decreased expression of TMPRSS4 on protein level.LncRNA SMARCC2 expression was increased in gastric cancer cells when compared with normal gastric epithelial cell,lncRNA SMARCC2 exerted positive effects on the proliferation and migration of gastric cancer cells.LncRNA SMARCC2 can regulate expression of miR-551b-3p negatively in gastric cancer cells.LncRNA SMARCC2 functions as a positive regulator of TMPRSS4 on protein level,partly by negative regulation miR-551b-3p.Conclusions1.miR-551b-3p expression was decreased in gastric cancer cases,and its expression was negatively correlated with depth of invasion and lymphatic metastasis,positively correlated with tumor differentiation and the patient survival time.2.miR-551b-3p affected gastric cancer cell proliferation,mobility and invasiveness negatively.3.TMPRSS4 is a target gene of miR-551b-3p.LncRNA SMARCC2 can interact with miR-551b-3p directly with its miRNA response elements,lncRNA SMARCC2 regulate miR-551b-3p expression negatively in gastric cancer cells.LncRNA SMARCC2 acts as a positive regulator of TMPRSS4 through ceRNA mechanism in gastric cancer cell SGC-7901.