AEG-1 promotes mesenchymal transition through the activation of Rho GTPases in human glioblastoma cells

Despite growing evidence indicating that astrocyte elevated gene-1 (AEG-1) plays pivotal roles in tumor progression in various types of human cancers including brain tumors; to date, its role in the regulation of mesenchymal transition is not clear in glioblastoma. In the present study, we investigated the contribution of AEG-1 to stress fiber formation and then the acquisition of mesenchymal characteristics of glioblastoma cells. Gain- and loss-of-function studies in normal immortalized primary human fetal astrocytes (IM-PHFAs) and glioblastoma cells revealed that overexpression of AEG-1 increased expression of mesenchymal markers including N-cadherin and two mesenchymal transition-inducing transcription factors ZEB1 and Slug but decreased epithelial markers E-cadherin and ZO-1. In addition, knockdown of AEG-1 suppressed invasive ability and migration of glioblastoma cells. Overexpression of AEG-1 also induced stress fiber formation and activated the Rho GTPase signaling pathways in glioblastoma cells. Consistently, treatment with an RhoA inhibitor decreased AEG-1-mediated stress fiber formation in glioblastoma cells. Collectively, our findings suggest that AEG-1 promotes mesenchymal transition in glioblastoma through the regulation of the Rho signaling pathway, resulting in tumor invasion, a primary characteristic of malignant brain tumors.