Astrocyte elevated gene-1(AEG-1) induces epithelial-mesenchymal transition in lung cancer through activating Wnt/beta-catenin signaling

作者:He, Weiling; He, Shanyang; Wang, Zuo; Shen, Hongwei; Fang, Wenfeng; Zhang, Yang; Qian, Wei; Lin, Millicent; Yuan, Jinglun; Wang, Jinyang; Huang, Wenhua; Wang, Liantang; Ke, Zunfu*
来源:BMC Cancer, 2015, 15(1): 107.
DOI:10.1186/s12885-015-1124-1

摘要

Background: Non-small cell lung cancer (NSCLC) is a highly metastatic cancer with limited therapeutic options, so development of novel therapies that target NSCLC is needed. During the early stage of metastasis, the cancer cells undergo an epithelial-mesenchymal transition (EMT), a phase in which Wnt/beta-catenin signaling is known to be involved. Simultaneously, AEG-1 has been demonstrated to activate Wnt-mediated signaling in some malignant tumors. Methods: Human NSCLC cell lines and xenograft of NSCLC cells in nude mice were used to investigate the effects of AEG-1 on EMT. EMT or Wnt/beta-catenin pathway-related proteins were characterized by western blot, immunofluorescence and immunohistochemistry. Results: In the present study, we demonstrated that astrocyte elevated gene-1(AEG-1) ectopic overexpression promoted EMT, which resulted from the down-regulation of E-cadherin and up-regulation of Vimentin in lung cancer cell lines and clinical lung cancer specimens. Using an orthotopic xenograft-mouse model, we also observed that AEG-1 overexpression in human carcinoma cells led to the development of multiple lymph node metastases and elevated mesenchymal markers such as Vimentin, which is a characteristic of cells in EMT. Furthermore, AEG-1 functioned as a critical protein in the regulation of EMT by directly targeting multiple positive regulators of the Wnt/beta-catenin signaling cascade, including GSK-3 beta and CKI delta. Notably, overexpression of AEG-1 in metastatic cancer tissues was closely associated with poor survival of NSCLC patients. Conclusions: These results reveal the critical role of AEG-1 in EMT and suggest that AEG-1 may be a prognostic biomarker and its targeted inhibition may be utilized as a novel therapy for NSCLC.