The Biological Roles and Molecular Mechanisms of Long Non-Coding RNA MEG3 in the Hallmarks of Cancer

SIMPLE SUMMARY: MEG3 is a class of lncRNA, which is considered a tumor suppressor. It is lost or decreased in different biological processes of various human tumors and is closely related to various diseases. MEG3 can modulate the expression of target genes through transcription, translation, post-translational modification and epigenetic regulation. Studies have shown that MEG3 dysfunction has been linked to a poor prognosis and drug resistance. MEG3 mediates the hallmarks of cancer through a variety of mechanisms, acting as a tumor suppressor to limit tumor growth. Hence, MEG3 is a potential prognostic marker and antitumor therapeutic target. ABSTRACT: Long non-coding RNAs (lncRNAs) are critical regulators in various biological processes involved in the hallmarks of cancer. Maternally expressed gene 3 (MEG3) is lncRNA that regulates target genes through transcription, translation, post-translational modification, and epigenetic regulation. MEG3 has been known as a tumor suppressor, and its downregulation could be found in various cancers. Furthermore, clinical studies revealed that impaired MEG3 expression is associated with poor prognosis and drug resistance. MEG3 exerts its tumor suppressive effect by suppressing various cancer hallmarks and preventing cells from acquiring cancer-specific characteristics; as it could suppress tumor cells proliferation, invasion, metastasis, and angiogenesis; it also could promote tumor cell death and regulate tumor cell metabolic reprogramming. Hence, MEG3 is a potential prognostic marker, and overexpressing MEG3 might become a potential antitumor therapeutic strategy. Herein, we summarize recent knowledge regarding the role of MEG3 in regulating tumor hallmarks as well as the underlying molecular mechanisms. Furthermore, we also discuss the clinical importance of MEG3, as well as their potential in tumor prognosis and antitumor therapeutic strategies.