MicroRNA-200b-3p suppresses epithelial-mesenchymal transition and inhibits tumor growth of glioma through down-regulation of ERK5.

Epithelial-mesenchymal transition (EMT) plays a pivotal role in the development of cancer. Has-miR-200b-3p is generally recognized as one of the fundamental regulators of EMT. In this study, we found that the expression of miR-200b-3p was downregulated in glioma tissues and human glioma cells U87 and U251. Meanwhile, Up-regulating miR-200b-3p enhanced E-cadherin, reduced mesenchymal markers, and decreased cell proliferation, migration, and invasion in vitro. In vivo, the xenograft mouse model also unveiled the suppressive effects of miR-200b-3p on tumor growth. Additionally, The extracellular-regulated protein kinase 5 (ERK5) was confirmed as a direct target gene of miR-200b-3p. The direct suppression of ERK5 expressions by miR-200b-3p was revealed by luciferase reporter assay, quantitative RT-PCR analysis, and western blot. Moreover, we observed an inverse correlation between miR-200b-3p and ERK5 in human glioma tissues. In summary, our findings demonstrated that miR-200b-3p suppresses glioma tumor growth, invasion, and reverses EMT through downregulated its target ERK5.