Preventing E-cadherin aberrant N-glycosylation at Asn-554 improves its critical function in gastric cancer

• DOI: 10.1038/onc.2015.225
• Publication Date: 2015-07-20T10:02:57Z
• Authors: S Carvalho; T A Catarino; A M Dias; M Kato; A Almeida; B Hessling; J Figueiredo; F Gärtner; J M Sanches; T Ruppert; E Miyoshi; M Pierce; F Carneiro; D Kolarich; R Seruca; Y Yamaguchi; N Taniguchi; C A Reis; S S Pinho
• Keywords: 0301 basic medicine; Glycosylation; Oncology and carcinogenesis not elsewhere classified; Molecular Sequence Data; Gastric Mucosa/pathology; Clinical sciences; Cadherins/metabolism; Stomach Neoplasms/genetics; N-Acetylglucosaminyltransferases/metabolism; N-Acetylglucosaminyltransferases; Stomach Neoplasms/metabolism; Madin Darby Canine Kidney Cells; Mice; 03 medical and health sciences; Catalytic Domain/genetics; Dogs; Stomach Neoplasms; Catalytic Domain; Cell Line, Tumor; Animals; Humans; Asparagine/genetics; Amino Acid Sequence; Gastric Mucosa/metabolism; Mice, Knockout; Sequence Homology, Amino Acid; Cadherins/genetics; Stomach Neoplasms/pathology; Oncology and carcinogenesis; N-Acetylglucosaminyltransferases/genetics; Cadherins; 3. Good health; Mice, Inbred C57BL; Gastric Mucosa; Cadherins/chemistry; Mutagenesis, Site-Directed; Asparagine; Cadherins/physiology; N-Acetylglucosaminyltransferases/antagonists & inhibitors; HT29 Cells

E-cadherin is a central molecule in the process of gastric carcinogenesis and its posttranslational modifications by N-glycosylation have been described to induce a deleterious effect on cell adhesion associated with tumor cell invasion. However, the role that site-specific glycosylation of E-cadherin has in its defective function in gastric cancer cells needs to be determined. Using transgenic mice models and human clinical samples, we demonstrated that N-acetylglucosaminyltransferase V (GnT-V)-mediated glycosylation causes an abnormal pattern of E-cadherin expression in the gastric mucosa. In vitro models further indicated that, among the four potential N-glycosylation sites of E-cadherin, Asn-554 is the key site that is selectively modified with β1,6 GlcNAc-branched N-glycans catalyzed by GnT-V. This aberrant glycan modification on this specific asparagine site of E-cadherin was demonstrated to affect its critical functions in gastric cancer cells by affecting E-cadherin cellular localization, cis-dimer formation, molecular assembly and stability of the adherens junctions and cell-cell aggregation, which was further observed in human gastric carcinomas. Interestingly, manipulating this site-specific glycosylation, by preventing Asn-554 from receiving the deleterious branched structures, either by a mutation or by silencing GnT-V, resulted in a protective effect on E-cadherin, precluding its functional dysregulation and contributing to tumor suppression.