Suppression of the Epithelial-Mesenchymal Transition by Grainyhead-Like-2
Menée sur des lignées cellulaires de cancers du sein, cette étude met en évidence le rôle joué par le gène GRHL2 pour supprimer la transition épithélio-mésenchymateuse
Grainyhead genes are involved in wound healing and developmental neural tube closure. In light of the high degree of similarity between the epithelial-mesenchymal transitions (EMT) occurring in wound healing processes and the cancer stem cell-like compartment of tumors, including TGF-β-dependence, we investigated the role of the Grainyhead gene, Grainyhead-Like-2 (GRHL2) in oncogenic EMT. GRHL2 was down-regulated specifically in the claudin-low subclass breast tumors and in basal-B subclass breast cancer cell lines. GRHL2 suppressed TGF-β-induced, Twist-induced or spontaneous EMT, enhanced anoikis-sensitivity, and suppressed mammosphere generation in mammary epithelial cells. These effects were mediated in part by suppression of ZEB1 expression via direct repression of the ZEB1 promoter. GRHL2 also inhibited Smad-mediated transcription and it upregulated mir200b/c as well as the TGF-β receptor antagonist, BMP2. Lastly, ectopic expression of GRHL2 in MDA-MB-231 breast cancer cells triggered a mesenchymal-to-epithelial transition and restored sensitivity to anoikis. Taken together, our findings define a major role for GRHL2 in the suppression of oncogenic EMT in breast cancer cells.