TEAD4 exerts pro-metastatic effects and is negatively regulated by miR6839-3p in lung adenocarcinoma progression.

: Several studies have shown the tumorigenesis role of transcriptional enhancer associate domain (TEAD) proteins; here, we initially explored expression, function and signalling mechanisms of TEAD4 in lung adenocarcinoma (LAD). Both the mRNA and protein levels of TEAD4 were increased in LAD tissues than those in adjacent nontumourous tissues. Besides, database search indicated a poorer clinical outcome in LAD patients with higher TEAD4 expression, revealing its potential tumour-promoting role. Therefore, we conducted cellular experiments to further investigate its effect on tumour phenotypes. Accordingly, TEAD4 showed little impact on LAD cell cycle, proliferation, or apoptosis. However, silencing TEAD4 remarkably attenuated cell migration and invasion capacities. Consistently, several important epithelial-mesenchymal transition (EMT) markers such as E-cadherin and Slug were consequently altered by silencing TEAD4. Furthermore, we identified a novel TEAD4-targeted microRNA, namely miR6839-3p, and confirmed its function in suppressing TEAD4 expression. Finally, the impact of overexpressing miR6839-3p mimics on LAD progression was validated, which showed a similar pattern with TEAD4 knockdown cells. Taken together, our data not only revealed the significant role of TEAD4 in promoting LAD progression and predicting clinical outcome but also distinguished miR6839-3p mimics as a promising therapeutic direction.