OBJECTIVE: This study aimed to investigate the role of long non-coding RNA MEG3 (lncRNA MEG3) in osteosarcoma (OS) and further explore the underlying molecular mechanism. MATERIALS AND METHODS: The expression profi les of MEG3 in OS cell lines and normal osteoblast cell line were detected by qRT-PCR. MEG3 was over-expressed in OS cell line by using LV-MEG3. MTT and colonyformation assays were applied for cell proliferation analysis. Cell migration assay was applied to investigate the cell migration ability. In addition, the expression levels of cell growth and metastasis related factors (Notch1, Hes1, TGF-β, N-cadheren and E-cadheren) were determined to illustrate the mechanisms. RESULTS: We found that compared with normal osteoblast hFOB1.19 cell line, MEG3 was signifi cantly downregulated in MG63 and U2OS cell lines, particularly in MG-63 cells. MEG3 was signifi cantly up-regulated in MG63 cells by LV-MEG3. Cell proliferation and migration ability were obviously repressed by MEG3 over-expression. In addition, MEG3 over-expression markedly inhibited Notch1, Hes1,TGF-β and N-cadheren expression, and the expression level of E-cadheren was improved. CONCLUSIONS: These results indicated that MEG3 could prevent cell growth and metastasis of OS by repressing Notch and TGF-β signaling pathway, thus providing a potential therapeutic target for OS treatment (Tab. 1, Fig. 4, Ref. 30). Text in PDF www.elis.sk.