Specific N‐glycan alterations are coupled in epithelial–mesenchymal transition induced by EGF in GE11 epithelial cells

Abstract

Epithelial-mesenchymal transition (EMT) is a phenomenon in cancer progression during which cancer cells undergo remarkable alteration acquiring highly invasive property. The aim of this study was to evaluate specific N-glycan alterations during EMT induced by epidermal growth factor (EGF) in GE11 epithelial cells. Herein, we demonstrated that EGF activated epidermal growth factor receptor (EGFR)/Akt/extracellular signal-regulated kinase (ERK) phosphorylation and promoted GE11 cell proliferation. Meanwhile, EGF stimulated the epithelial cells to undergo morphological alteration, destroying cell-cell inter-contact and exhibiting mesenchymal cells higher metastatic potential. A wound-healing assay showed the migratory ability increased 1.5-fold after EGF treatment. Moreover, the relative intensity of N-cadherin versus E-cadherin increased 2.6-fold, and the E-cadherin distribution in cell-cell junctions became jagged and faint after EGF incubation for 72 h. Interestingly, the amounts of bisecting GlcNAc structure were dramatically declined, by contrast, the formation of β1,6 GlcNAc branches on cell surface was upregulated during EMT induced by EGF. To understand the roles of N-glycans in EGF-induced EMT, the cells were stably transfected with N-acetylglucosaminyltransferase III (GnT-III), which catalyzes the bisecting GlcNAc structure formation. As the markers for EMT, EGF-induced E-cadherin decrease and fibronectin increase were delayed in GnT-III-overexpressing cells. Taken together, these results demonstrated that specific N-glycan alterations were coupled in EMT induced by EGF, which might be contributed to diagnosis and therapy of tumor metastasis.