| Glioma is the most common tumor of the central nervous system, accounting for40%~50%of primary intracranial tumors. Traditional therapy include operation,radiotherapy and chemotherapy. But because of its infiltrating growth, the boundaries oftumor tissue and surrounding normal brain tissue are not clear, total resection is difficult,and the general effect is not satisfactory, also it is easy to recurrence after surgery.Radiotherapy and chemotherapy are often used as auxiliary means after the operation.But they can not high specificly kill tumor cells, also may produce side effects of centralnervous system.So the treatment of glioma is always one of the difficult problems inthe Department of neurosurgery. Exploreing a new treatment of glioma, especially themechanism of its occurrence, development and evolution on gene level, finding aneffective target of gene therapy is the hotspot and difficulty in research of Department ofneurosurgery in recent years.Long non coding RNA (lncRNA) is a kind of non protein coding RNA and itslength is greater than200nucleotides. Research shows that lncRNA can regulate geneexpression on the level of epigenetics, transcription and post transcription bychromosome modification, transcriptional activation or interference. There is a closerelationship between lncRNA and tumors. The expression of lncRNA in some tumortissues and their normal tissues are significantly difference. Abnormal lncRNA may playan important role in tumorigenesis. So we predict that lncRNAs could act as a newmarker of diagnosis and judgment of prognosis and therapeutic effect of tumor,meanwhile as a new therapeutic target in cancer gene therapy.At present, research about lncRNA in central nervous system tumors is little.Protein coding gene TSLC1has been identified as the tumor suppressor gene which isoften down-regulated by hypermethylation in many tumors, including glioma, lungcancer, neuroblastoma, nasopharyngeal cancer, malignant melanoma, esophageal cancer,liver cancer, breast cancer, gastric cancer, pancreatic cancer, colorectal cancer, cervical cancer and prostate cancer. While TSLC1-AS1, the antisense transcript of TSLC1, as amember of the lncRNA families, its expression in glioma and its function in occurrence,development of glioma have not been reported.In this study, real-time quantitative PCR were used to detect the expression oflncRNA TSLC1-AS1and mRNA TSLC1in30cases of glioma tissues and30cases ofnormal brain tissues, and in glioma cell lines U87, U251and SNB19. The differenceexpression of TSLC1-AS1in glioma tissues and normal brain tissues, differentexpression in different grades of glioma, and correlation of its expression with TSLC1were studied. The results showed TSLC1-AS1and TSLC1expression levels in gliomawere significantly down-regulated compared with normal brain tissues（P＜0.05）. Theexpression levels of TSLC1-AS1and TSLC1were significantly lower in tumors ofhigher pathological stage than that in tumors of lower pathological stage（P＜0.05）. TheTSLC1-AS1expression was positively correlated with TSLC1expression（R=0.66，P<0.01）. These results suggest that the expression of TSLC1-AS1in glioma cellsdecreased significantly, and its expression level decreased with glioma’s malignantdegree.It can be used as a molecular index to diagnose brain glioma, and its clinicalclassification and prognosis. Then the pcDNA-TSLC1-AS1was transfected into humanglioma cell line U87to upregulate the expression of TSLC1-AS1, and cell proliferation,migration of U87were detected by MTS cell proliferation assay and Transwell assay.The results showed TSLC1-AS1expression was markedly elevated（P＜0.05）, andTSLC1expression level was also evidently up-regulated by TSLC1-AS1cDNA plasmid（P＜0.05）. U87cells in pcDNA-TSLC1-AS1group grew significantly slowercompared with the cells in the pcDNA control group（P＜0.05）. The Transwell assayalso showed significant cell migration inhibition in the pcDNA-TSLC1-AS1groupcompared with the pcDNA control group（P＜0.05）. Then TSLC1-AS1siRNA wastransfected into SNB19cell line to knock-down the expression of TSLC1-AS1. Thebiological characteristics of glioma cell line SNB19were studied by MTS cellproliferation assay and Transwell assay. The results showed TSLC1-AS1expressionwas markedly decreased. Quantification analysis showed that TSLC1-AS1was knocked down nearly90%in TSLC1-AS1siRNA group and TSLC1expressionlevel was also down-regulated by TSLC1-AS1siRNA compared with negative control groups（P＜0.05）. It was found that only the sense strand of TSLC1-AS1siRNAsuccessfully knocked down the expression of both TSLC1-AS1and TSLC1（P＜0.05）,while the antisense strand had no effect on the TSLC1expression（P>0.05）. The resultsshowed that the SNB19cells in TSLC1-AS1siRNA transfected groups grewsignificantly faster compared with the cells in the negative control group（P＜0.05）. TheTranswell assay also showed significant cell migration elevation in the TSLC1-AS1siRNA group compared with the negative control group（P＜0.05）. These resultssuggest that overexpression of TSLC1-AS1can up-regulate expression of TSLC1andinhibit the proliferation, migration of glioma, and vice versa. The study provides atheoretical basis to target treatment of brain glioma. |
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