Long non-coding RNA MEG3 inhibits NSCLC cells proliferation and induces apoptosis by affecting p53 expression

Abstract

BackgroundLong non-coding RNAs play an important role in tumorigenesis, hence, identification of cancer-associated lncRNAs and investigation of their biological functions and molecular mechanisms are important for understanding the development and progression of cancer. Recently, the downregulation of lncRNA MEG3 has been observed in various human cancers. However, its role in non-small cell lung cancer (NSCLC) is unknown. The aim of this study was to examine the expression pattern of MEG3 in NSCLC and to evaluate its biological role and clinical significance in tumor progression.MethodsExpression of MEG3 was analyzed in 44 NSCLC tissues and 7 NSCLC cell lines by qRT-PCR. Over-expression approaches were used to investigate the biological functions of MEG3 in NSCLC cells. Bisulfite sequencing was used to investigate DNA methylation on MEG3 expression. The effect of MEG3 on proliferation was evaluated by MTT and colony formation assays, and cell apoptosis was evaluated by Hoechst staining and Flow-cytometric analysis. NSCLC cells transfected with pCDNA-MEG3 were injection into nude mice to study the effect of MEG3 on tumorigenesis in vivo . Protein levels of MEG3 targets were determined by western blot analysis. Differences between groups were tested for significance using Student’s t-test (two-tailed).ResultsMEG3 expression was decreased in non-small cell lung cancer (NSCLC) tumor tissues compared with normal tissues, and associated with advanced pathologic stage, and tumor size. Moreover, patients with lower levels of MEG3 expression had a relatively poor prognosis. Overexpression of MEG3 decreased NSCLC cells proliferation and induced apoptosis in vitro and impeded tumorigenesis in vivo. MDM2 and p53 protein levels were affected by MEG3 over-expression in vitro.ConclusionsOur findings indicate that MEG3 is significantly down-regulated in NSCLC tissues that could be affected by DNA methylation, and regulates NSCLC cell proliferation and apoptosis, partially via the activition of p53. Thus, MEG3 may represent a new marker of poor prognosis and is a potential therapeutic target for NSCLC intervention.

Expression and Prognostic Significance of lncRNA MALAT1 in Pancreatic Cancer Tissues

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Pan-cancer transcriptome analysis reveals long noncoding RNAs with conserved function

“…Interestingly, MEG3 has already been found to promote cellular proliferation and induce apoptosis in non-small cell lung carcinoma (NSCLC) by affecting TP53 target gene expression. 40 This suggests that the oncogene regulates a lncRNA, MEG3, and that the lncRNA can regulate many downstream targets. Taken together, the association of lncRNA expression with mutational status potentially implicates some of the onco-lncRNAs in specific well-known cancer pathways.…”

Downregulation of BC200 in ovarian cancer contributes to cancer cell proliferation and chemoresistance to carboplatin

“…To date, lncRNAs, including maternally expressed 3 (MEG3) and papillary thyroid carcinoma susceptibility candidate 3 (PTCSC3), have been reported to function as tumor suppressors. Downregulation of MEG3 has been observed in various types of human cancer, and the lncRNA has been demonstrated to inhibit cancer cell proliferation and induce apoptosis (27,28). PTCSC3 is a newly identified, thyroid-specific lncRNA that is significantly downregulated in thyroid cancer.…”