The binding of lncRNA RP11-732M18.3 with 14-3-3 β/α accelerates p21 degradation and promotes glioma growth

Background: Long noncoding RNAs (lncRNAs) have been identified as regulators of a number of developmental and tumorigenic processes. However, the functions of most lncRNAs in glioma remain unknown and the mechanisms governing the proliferation of tumor cells remain poorly defined. Methods: Both in vitro and in vivo assays were performed to investigate the roles of lncRNAs in the pathophysiology of gliomas. lncRNA arrays were used to identify differentially expressed lncRNAs. Subcutaneous tumor formation and a brain orthotopic tumor model in nude mice were used to investigate the functions of lncRNAs in vivo. The in vitro functions of lncRNAs were analyzed by fluorescence-activated cell sorting, colony formation, and western blot analyses. RNA fluorescence in situ hybridization and immunoprecipitation were used to explore the underlying mechanisms. Findings: Here, we describe the newly discovered noncoding RNA RP11-732M18.3, which is highly overexpressed in glioma cells and interacts with 14-3-3 beta/alpha to promote glioma growth, acting as an oncogene. Overexpression of lncRNA RP11-732 M18.3 was associated with the proliferation of glioma cells and tumor growth in vitro and in vivo. Remarkably, lncRNA RP11-732M18.3 promoted cell proliferation and G1/S cell cycle transition. lncRNA RP11-732M18.3 is predominately localized in the cytoplasm. Mechanistically, the interaction of lncRNA RP11-732M18.3 with 14-3-3 beta/alpha increases the degradation of the p21 protein. lncRNA RP11-732M18.3 promoted the recruitment of ubiquitin-conjugating enzyme E2 E1 to 14-3-3 beta/alpha and the binding of 14-3-3 beta/alpha with ubiquitin-conjugating enzyme E2 E1 (UBE2E1) promoted the degradation of p21. Interpretation: Overall these data demonstrated that lncRNA RP11-732M18.3 regulates glioma growth through a newly described lncRNA-protein interaction mechanism. The inhibition of lncRNA RP11-732M18.3 could provide a novel therapeutic target for glioma treatment. (C) 2019 Published by Elsevier B.V.