Expression And Function Study Of Long Noncoding RNA SNHG12 In Glioma

Background:Glioma,deriving from cancerization of glial cells in brain and spinal cord,is the most common primary tumor in central nervous system.Patients suffering from this disease show a mean survival time of 12-15 months although clinical therapies such as resection techniques,radiation therapies and chemotherapeutic strategies have made large progress in recent decades.So it is urgent to develop new effective treatments.Long noncoding RNAs are a class of RNAs which are more than 200 nt in length without protein-coding capacity.Nowadays,an increasing number of studies have proved that lncRNAs own the ability to regulate gene expression,which indicates that lncRNAs are involved in multiple biological process such as proliferation,migration,cell cycle and apoptosis.Recent studies have demonstrated that lncRNA SNHG12 is up-regulated and promotes tumorigenesis in various cancers such as osteosarcoma,colorectal cancer and hepatocellular carcinoma.However,the specific expression of SNHG12 in glioma and its biological function in glioma cells has not been clearly illustrated.Objective:This study aimed to investigate the expression of long noncoding RNA SNHG12 in glioma and its effect on cell proliferation,invasion and migration in glioma,and explore underlying mechanisms.Methods:The expression of SNHG12 in glioma tissues of different grades was analyzed within the Chinese Glioma Genome Atlas expression(CGGA)Database and Repository of Molecular Brain Neoplasia Data(REMBRANT)Database,and quantitative real-time PCR analysis was performed to detect the expression level of SNHG12 in nineteen glioma tissues and five normal brain tissues.The correlation between the expression of SNHG12 and the clinical survival of glioma patients was analyzed within CGGA and REMBRANT Database.The specific siRNA targeting SNHG12 was transfected into U251 and U87 glioma cells with Lipofectamine 2000,and the change of SNHG12 expression was evaluated by qRT-PCR.Then CCK-8 assay was performed to detect the effect SNHG12 has on proliferation of glioma cells.Transwell assay was conducted to evaluate the migration and invasion efficiency of glioma cells.Flow cytometry was used to analyze cell cycle of glioma cells.Gene ontology(GO)analysis and pathway analysis using KEGG and Reactome Database was performed to acquire major biological function and relevant signaling pathway of SNHG12.Western blotting assays were performed to investigate changes in CDK4?CDK6?Vimentin and MMP-9 proteins,which are related to cell proliferation,invasion and migration after knockdown of SNHG12.The microRNAs which were negatively correlated with SNHG12 were detected within miRcode and CGGA Database,then we used qRT-PCR and Dual-Luciferase reporter assay to identify the relationship between SNHG12 and miR-181b-5p.Results:SNHG12 expression was significantly up-regulated in glioma tissues compared with normal brain tissue,and its expression level was correlated with the grade of malignancy.The high expression of SNHG12 was associated with poor survival time of glioma patients.What's more,knockdown of SNHG12 resulted in reduce of proliferation,invasion and migration in U251 and U87 glioma cells,and suppressed cell cycle progression.GO and pathway analysis showed that SNHG12 was related to telomere maintenance,extracellular matrix regulation,cell adhesion,cell cycle,nuclear division and other biological processes in glioma.The protein expressions of CDK4,CDK6,Vimentin and MMP-9 were decreased after SNHG12 silencing.The expression of miR-181b-5p was negatively correlated with SNHG12,the luciferase activity in the SNHG12-Wt+miR-181b-5p mimics group was lower than that in the control group.Conclusions:The expression of long noncoding RNA SNHG12 is significantly up-regulated in glioma tissues compared with normal brain tissue,and is correlated with the malignant degree of glioma.SNHG12 could enhance the abilities of glioma cells proliferation,invasion and migration,and accelerate cell cycle.SNHG12 may regulate biological function and promote cancer process by targeting miR-181b-5p and activate related proteins such as CDK4,CDK6,Vimentin and MMP-9.