Succinate dehydrogenase 5 (SDH5) regulates glycogen synthase kinase 3β-β-catenin-mediated lung cancer metastasis.

We demonstrate that loss of succinate dehydrogenase 5 (SDH5) expression initiates epithelial-mesenchymal transition (EMT), which is visualized by the repression of E-cadherin and up-regulation of vimentin in lung cancer cell lines and clinical lung cancer specimens. In SDH5 knock-out mice, lung epithelial cells exhibited elevated mesenchymal markers, which is characteristic of EMT. Using a human lung xenograft-mouse model, we observed that knocking down endogenous SDH5 in human carcinoma cells leads to the development of multiple lymph node metastases. Moreover, our data indicate that SDH5 functions as a critical protein in regulating EMT by modulating the glycogen synthase kinase (GSK)-3β-β-catenin signaling pathway. These results reveal a critical role for SDH5 in EMT and suggest that SDH5 may be a prognostic biomarker and potential therapeutic target for lung cancer metastasis.