MiR-138-5p suppresses lung adenocarcinoma cell epithelial-mesenchymal transition, proliferation and metastasis by targeting ZEB2

Background: MiR-138-5p is regarded as a tumour suppressor in many cancers. Transforming growth factor beta (TGF-beta) often acts as a tumor promotor at the late stages of human cancers. However, the function of miR-138-5p on lung adenocarcinoma cells induced by TGF-beta remains to be further confirmed. Methods: RT-qPCR was used to detect the expression of human lung adenocarcinoma tissues, adjacent normal tissues, and relative cell lines. When the lung adenocarcinoma cells A549 and H1299 were transfected with negative control (NC), miR-138-5p mimics and miR-138-5p inhibitor by lipofectamine3000 and treated with or without TGF-beta 1, the lung adenocarcinoma cell function was detected by Immunofluorescence, Western blotting (WB), cell counting Kit-8 (CCK8), colony formation, EdU, Wound-healing and Transwell assays. The relation between miR-138-5p and zinc finger E-box-binding homeobox 2 (ZEB2) was detected by RT-qPCR, WB, and Luciferase reporter assays. When ZEB2 was knocked down, the lung adenocarcinoma cell function was detected by WB, CCK8 and Transwell assays. Results: The expression of miR-138-5p was decreased in lung adenocarcinoma tissues and cell lines. When treated with or without TGF-beta 1, overexpression of miR-138-5p suppressed EMT, proliferation and metastasis of A549 and H1299. ZEB2 was verified as the direct target of miR-138-5p. Downregulation of ZEB2 suppressed EMT, proliferation and metastasis of lung adenocarcinoma cell, which could be reversed by miR-138-5p inhibitor. Conclusions: MiR-138-5p inhibits epithelial-mesenchymal transition, growth and metastasis of lung adenocarcinoma cells through targeting ZEB2.