Paraquat promotes the epithelial-mesenchymal transition in alveolar epithelial cells through regulating the Wnt/β-catenin signal pathway.

Objective: To investigate whether paraquat (PQ)-induced rat alveolar type II cells (RLE-6TN) epithelial-mesenchymal transition (EMT) and to explore the underlying molecular mechanism. Materials and

Methods: In the present study, RLE-6TN cells were treated by 20 μmol/L PQ, and then the morphology was observed under an inverted microscope; RT-PCR and Western blot were performed to detect the expression level of EMT related markers, E-cadherin, and vimentin, as well as Wnt/β-catenin signaling pathway. In addition, we performed the transwell invasion assay to detect the ability of cell invasion.

Results: We demonstrated that PQ was able to induce the transition of RLE-6TN cells from epithelial morphology to fibroblast-like morphology, associated with the acquisition of migratory properties. Phenotypically, PQ induced-EMT was characterized by loss of epithelial cell markers including E-cadherin, while upregulation of mesenchymal cell markers including vimentin, was concurrent with the activation of Wnt/β-catenin signaling pathway. Furthermore, knockdown of β-catenin by using specific siRNA could reverse PQ triggered EMT process and attenuated cell migration ability.

Conclusions: PQ promotes RLE-6TN epithelial-mesenchymal transition by upregulating the expression of Wnt/β-catenin.