MiR-145 inhibits EGF-induced epithelial-to-mesenchymal transition via targeting Smad2 in human glioblastoma

Background/Aims: MiR-145 and Smad2 have been widely reported in the development and progression of human malignancies. In the present study, we investigated the correlation between miR-145 and Smad2 in human glioblastoma multiforme (GBM). Methods: The epithelial–mesenchymal transition (EMT) biomarkers and Smad2 were assessed by Western blot. The silencing of Smad2 was conducted by transfection of Smad2 siRNAs. The cell migration and invasion were evaluated using Transwell assays, respectively. The dual luciferase reporter assay was performed to identify whether Smad2 is a direct target of miR-145. Results: The epidermal growth factor (EGF) activated the phosphorylation of Smad2 in U87 and U251 cells in a time- and dose-dependent manner. However, treatment with silencing of Smad2 or overexpression of miR-145 significantly inhibited the expressions of total Smad2, N-cadherin, Vimentin and matrix metallopeptidase 9, but induced the expression of E-cadherin. In addition, silencing of Smad2 or overexpression of miR-145 also inhibited the migration and invasion of U87 and U251 cells. Mechanistically, Smad2 was confirmed to be a target gene of miR-145 by bioinformatics analysis and luciferase reporter assay. Restored Smad2 expression also reversed miR-145-induced inhibition of EMT in U87 and U251 cells. Conclusion: MiR-145 inhibits EGF-induced EMT via targeting Smad2 in human GBM. Therefore, miR-145 may be a promising biomarker and therapeutic target for GBM patients.