LncRNA MEG3 suppresses the tumorigenesis of hemangioma by sponging miR-494 and Regulating PTEN/ PI3K/AKT Pathway

Abstract

Background/Aims: Dysregulation of long noncoding RNAs (lncRNAs) is associated with the proliferation and metastasis in a variety of cancers, of which lncRNA maternally expressed gene 3 (MEG3) has been indicated as a tumor suppressor in multiple malignancies. However, the underlying mechanisms by which MEG3 contributes to human hemangiomas (HAs) remain undetermined. Methods: qRT-PCR analysis was performed to examine the expression levels of MEG3 and VEGF in proliferating or involuting phase HAs. MTT, colony formation assay, flow cytometry analysis and a subcutaneous xenograft tumor model were conducted to assess the effects of MEG3 on the HAs tumorigenesis. The interaction between MEG3 and miRNAs or their downstream pathways was evidenced by bioinformatic analysis, luciferase report assays, RNA immunoprecipitation (RIP) assay. and Western blot analysis. Results: The expression of MEG3 was substantially decreased and had a negative correlation with VEGF expression in proliferating phase HAs, as compared with the involuting phase HAs and normal skin tissues. Ectopic expression of MEG3 suppressed cell proliferation, colony formation and induced cycle arrest in vitro and in vivo, followed by the downregulation of VEGF and cyclinD1, but knockdown of MEG3 reversed these effects. Furthermore, MEG3 was verified to act as a sponge of miR-494 in HAs cells, and miR-494 counteracted MEG3-caused anti-proliferative effects by regulating PTEN/PI3K/AKT pathway, and exhibited the negative correlation with MEG3 and PTEN expression in proliferating phase HAs. Conclusion: Our findings suggested that lncRNA MEG3 inhibited HAs tumorigenesis by sponging miR-494 and regulating PTEN/PI3K/AKT pathway.