Maternally expressed gene 3 (MEG3),a long non-coding RNA,inhibits the growth of various cancer cells by regulating downstream targeted genes.The aim of this study was to investigate MEG3 expression in epithelial ovarian cancer (EOC),and to explore the role of MEG3 in EOC cells and the underlying mechanisms.MEG3 expression in EOC tissues (n =67) and normal ovarian tissues (n =20) was examined by RT-PCR,and its correlation with the clinicopathological characteristics of EOCs was analyzed.The role of MEG3 in ovarian cancer cell growth was investigated in MEG3-overxpressing OVCAR3 and SKOV3 cells using MTT assays and flow cytometric cell cycle analysis.The transcriptional activity of the MEG3-targeted gene,Rbl,was analyzed using the dual luciferase reporter system.Rbl mRNA and protein levels were detected by RT-PCR and Western blot analyses,respectively.The relative MEG3 levels in EOC tissues (0.35 + 0.11) were significantly decreased compared to those in normal ovarian tissues (3.32 + 0.25),and were negatively correlated with the International Federation of Gynecology and Obstetrics stage,but not related to tumor pathological type and grade.MEG3 overexpression inhibited proliferation of OVCAR3 and SKOV3 cells in vitro.Furthermore,the transcriptional activity,mRNA and protein levels of Rb I were dramatically upregulated after MEG3 overexpression.MEG3 inhibits the proliferation of EOC cells by targeting Rbl.