Loss and Recovery of Mgat3 and GnT-III Mediated E-cadherin N-glycosylation Is a Mechanism Involved in Epithelial-Mesenchymal-Epithelial Transitions

Abstract

BackgroundN-acetylglucosaminyltransferase-III (GnT-III) is a glycosyltransferase encoded by Mgat3 that catalyzes the addition of β1,4-bisecting-N-acetylglucosamine on N-glycans. GnT-III has been pointed as a metastases suppressor having varying effects on cell adhesion and migration. We have previously described the existence of a functional feedback loop between E-cadherin expression and GnT-III-mediated glycosylation. The effects of GnT-III-mediated glycosylation on E-cadherin expression and cellular phenotype lead us to evaluate Mgat3 and GnT-III-glycosylation role during Epithelial-Mesenchymal-Transition (EMT) and the reverted process, Mesenchymal-Epithelial-Transition (MET).Methodology/Principal FindingsWe analyzed the expression profile and genetic mechanism controlling Mgat3 expression as well as GnT-III-mediated glycosylation, in general and specifically on E-cadherin, during EMT/MET. We found that during EMT, Mgat3 expression was dramatically decreased and later recovered when cells returned to an epithelial-like phenotype. We further identified that Mgat3 promoter methylation/demethylation is involved in this expression regulation. The impact of Mgat3 expression variation, along EMT/MET, leads to a variation in the expression levels of the enzymatic product of GnT-III (bisecting GlcNAc structures), and more importantly, to the specific modification of E-cadherin glycosylation with bisecting GlcNAc structures.Conclusions/SignificanceAltogether, this work identifies for the first time Mgat3 glycogene expression and GnT-III-mediated glycosylation, specifically on E-cadherin, as a novel and major component of the EMT/MET mechanism signature, supporting its role during EMT/MET.

Specific Glycosylation of Membrane Proteins in Epithelial Ovarian Cancer Cell Lines: Glycan Structures Reflect Gene Expression and DNA Methylation Status

“…This correlates strongly with our finding of an increased proportion of complex type N-glycans in the non-cancerous cells as compared with the serous ovarian cancer cells. A recent study demonstrated that MGAT3 mediated E-cadherin N-glycosylation is involved in epithelialmesenchymal transitions and their findings point to an involvement of DNA methylation as a regulatory mechanism of MGAT3 (55). This supports our finding that the expression of bisecting GlcNAc on the entire N-glycoproteome is indeed a result of DNA hypomethylation of MGAT3 transcriptional regulatory elements in serous ovarian cancer cells.…”

Glycans and Cancer

“…At the molecular levels, it has been suggested that GnT-III and the bisecting GlcNAc play roles in cell adhesion and migration by altering the N-glycans in adhesion molecules and the extracellular matrix such as E-cadherin, laminin, and integrin (Gu & Taniguchi, 2008;Isaji et al, 2004;Kariya et al, 2008;Kariya, Kawamura, Tabei, & Gu, 2010;Kitada et al, 2001;Pinho et al, 2012Pinho et al, , 2011Sato et al, 2009;Yoshimura, Ihara, Matsuzawa, & Taniguchi, 1996;Zhao et al, 2006). The expression of GnT-III was found to be upregulated by E-cadherin-mediated cell adhesion.…”

“…Moreover, glycosylation plays a pivotal role in cancer progression and metastasis, cell-cell contact, and epithelial-mesenchymal transition (EMT) in cancer cells (Chen et al, 2013;Kalluri & Weinberg, 2009;Li et al, 2014;Pinho et al, 2012;Tan et al, 2014;Terao et al, 2011;Xu et al, 2012). In recent years, EMT has become the important issue for understanding the development and metastasis of cancer (Kalluri & Weinberg, 2009), and in fact, changes in N-glycan structures are considered to be important for understanding the significance of EMT and the resultant change of adhesive properties of cancer cells (Chen et al, 2013;Li et al, 2014;Pinho et al, 2012;Tan et al, 2014;Terao et al, 2011;Xu et al, 2012).…”

Contribution to study the glycoprotein ligands of the cerebellar soluble lectin in human K562 tumour cells

“…Asn-X-(Ser/thr), however, the precise regulation process implicated in the N-glycosylation is still unknown [45,46]. It has been suggested that the N-glycosylation concerns only the accessible asparagine.…”