Downregulation of miR-452 promotes stem-like traits and tumorigenicity of gliomas

Purpose: miR-452 is reported to be required for neural crest stem cell differentiation during neural crest development. However, the biologic role of miR-452 in gliomas remains unclear. The aim of the present study was to evaluate the effect of miR-452 on the stem-like properties and tumorigenesis of glioma cells. Experimental Design: The expression of miR-452 was examined in glioma cells and glioma tissues using real-time PCR. The effects of miR-452 on stem-like traits and tumorigenesis were investigated in vitro and in vivo using patient-derived glioma cells and glioma cell lines. Western blotting and luciferase reporter assays were conducted to examine the negative regulation of Bmi-1, LEF1, and TCF4 by miR-452. The methylation of the miR-452 promoter region was examined by bisulfite genomic sequencing PCR. Results: miR-452 was markedly downregulated in glioma cells and clinical glioma tissues. miR-452 levels were inversely correlated with World Health Organization (WHO) grades and patient survival. miR-452 directly targeted and suppressed multiple stemness regulators, including Bmi-1, LEF1, and TCF4, resulting in reduced stem-like traits and tumorigenesis of glioma cells in vitro and in vivo. Furthermore, we showed that downregulation of miR-452 in gliomas was caused by hypermethylation of its promoter region. Conclusions: Downregulation of miR-452 plays an important role in promoting the stem-like traits and tumorigenesis of gliomas and may represent a novel prognostic biomarker and therapeutic target for the disease.