miR-21 regulates growth and EMT in lung cancer cells via PTEN/Akt/GSK3β signaling.

miRNA-21 (miR-21) is overexpressed in various human cancers. Here, we show that miR-21 is overexpressed in human Non-Small Cell Lung Cancer (NSCLC)  and that its up or down-regulation, respectively, increases or decreases cyclin D1 and cyclin E1 expression and coordinately promotes or inhibits proliferation of cancer cells. The perturbations of miR-21 also dramatically reduces or increases epithelial to mesenschymal transition (EMT). We show that regulation of proliferation and EMT are directed by PTEN/Akt/GSK3 beta signaling axis by regulating the expression of invasion markers including E-cadherin, vimentin, snail, slug and beta-catenin. Together, these findings show that miR-21 is a potential target for the development of treatment for NSCLC forms of human lung cancer.