Circ-EZH2 knockdown reverses DDAH1 and CBX3-mediated cell growth and invasion in glioma through miR-1265 sponge activity

Accumulating evidence has indicated the important roles of circular RNAs (circRNAs) in different tumors. However, their detailed regulatory mechanisms in glioma are not fully understood. In this study, the functional role of a novel circRNA, circ-EZH2, was investigated by cell counting kit-8 (CCK-8), colony formation, flow cytometry, and transwell experiments. The regulatory mechanism of circ-EZH2 was explored by bioinformatics analysis, quantitative real-time PCR (qRT-PCR), Western blot and dual-luciferase reporter assay. We identified that circ-EZH2 was overexpressed in glioma tissues and cell lines. Further studies revealed that ectopic expression of circ-EZH2 significantly promoted cell growth, migration and invasion but inhibited cell apoptosis. By contrast, silencing of circ-EZH2 induced the opposite effects. Additionally, we found circ-EZH2 served as a miRNA sponge for miR-1265 to release its suppression on DDAH1 and CBX3. Rescue assays further revealed that the oncogenic function of circ-EZH2 was partly dependent on its modulation of DDAH1 and CBX3. Our study unraveled a novel molecular pathway in glioma and may provide a new perspective for the treatment of glioma.