title: Glycomic analysis of gastric carcinoma cells discloses glycans as modulators of RON receptor tyrosine kinase activation in cancer.
abstract: BACKGROUND
  Terminal α2-3 and α2-6 sialylation of glycans precludes further chain elongation, leading to the biosynthesis of cancer relevant epitopes such as sialyl-Lewis X (SLe(X)). SLe(X) overexpression is associated with tumor aggressive phenotype and patients' poor prognosis.
  
  
  METHODS
  MKN45 gastric carcinoma cells transfected with the sialyltransferase ST3GAL4 were established as a model overexpressing sialylated terminal glycans. We have evaluated at the structural level the glycome and the sialoproteome of this gastric cancer cell line applying liquid chromatography and mass spectrometry. We further validated an identified target expression by proximity ligation assay in gastric tumors.
  
  
  RESULTS
  Our results showed that ST3GAL4 overexpression leads to several glycosylation alterations, including reduced O-glycan extension and decreased bisected and increased branched N-glycans. A shift from α2-6 towards α2-3 linked sialylated N-glycans was also observed. Sialoproteomic analysis further identified 47 proteins with significantly increased sialylated N-glycans. These included integrins, insulin receptor, carcinoembryonic antigens and RON receptor tyrosine kinase, which are proteins known to be key players in malignancy. Further analysis of RON confirmed its modification with SLe(X) and the concomitant activation. SLe(X) and RON co-expression was validated in gastric tumors.
  
  
  CONCLUSIONS
  The overexpression of ST3GAL4 interferes with the overall glycophenotype of cancer cells affecting a multitude of key proteins involved in malignancy. Aberrant glycosylation of the RON receptor was shown as an alternative mechanism of oncogenic activation.
  
  
  CONCLUSIONS
  This study provides novel targets and points to an integrative tumor glycomic/proteomic-profiling for gastric cancer patients' stratification. This article is part of a Special Issue entitled "Glycans in personalised medicine" Guest Editor: Professor Gordan Lauc.
authors.affiliation: I3S - Instituto de Investigação e Inovação em Saúde, University of Porto, Portugal; Institute of Molecular Pathology and Immunology of the University of Porto - IPATIMUP, Porto, Portugal; Institute of Biomedical Sciences of Abel Salazar - ICBAS, University of Porto, Portugal.
authors.forename: Stefan
authors.initials: S
authors.lastname: Mereiter
authors.affiliation: I3S - Instituto de Investigação e Inovação em Saúde, University of Porto, Portugal; Institute of Molecular Pathology and Immunology of the University of Porto - IPATIMUP, Porto, Portugal.
authors.forename: Ana
authors.initials: A
authors.lastname: Magalhães
authors.affiliation: Department of Medical Biochemistry and Cell Biology, Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, Sweden.
authors.forename: Barbara
authors.initials: B
authors.lastname: Adamczyk
authors.affiliation: Department of Medical Biochemistry and Cell Biology, Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, Sweden.
authors.forename: Chunsheng
authors.initials: C
authors.lastname: Jin
authors.affiliation: Department of Biomolecular Systems, Max Planck Institute of Colloids and Interfaces, 14424 Potsdam, Germany; Free University Berlin, Berlin, Germany.
authors.forename: Andreia
authors.initials: A
authors.lastname: Almeida
authors.affiliation: Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense, Denmark.
authors.forename: Lylia
authors.initials: L
authors.lastname: Drici
authors.affiliation: Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense, Denmark.
authors.forename: Maria
authors.initials: M
authors.lastname: Ibáñez-Vea
authors.affiliation: I3S - Instituto de Investigação e Inovação em Saúde, University of Porto, Portugal; Institute of Molecular Pathology and Immunology of the University of Porto - IPATIMUP, Porto, Portugal.
authors.forename: Catarina
authors.initials: C
authors.lastname: Gomes
authors.affiliation: I3S - Instituto de Investigação e Inovação em Saúde, University of Porto, Portugal; Institute of Molecular Pathology and Immunology of the University of Porto - IPATIMUP, Porto, Portugal; Experimental Pathology and Therapeutics Group, Portuguese Institute of Oncology of Porto, Portugal.
authors.forename: José A
authors.initials: JA
authors.lastname: Ferreira
authors.affiliation: Department of Pathology, Portuguese Institute of Oncology of Porto, Portugal.
authors.forename: Luis P
authors.initials: LP
authors.lastname: Afonso
authors.affiliation: Experimental Pathology and Therapeutics Group, Portuguese Institute of Oncology of Porto, Portugal; Department of Surgical Oncology, Portuguese Institute of Oncology of Porto, Portugal.
authors.forename: Lúcio L
authors.initials: LL
authors.lastname: Santos
authors.affiliation: Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense, Denmark.
authors.forename: Martin R
authors.initials: MR
authors.lastname: Larsen
authors.affiliation: Department of Biomolecular Systems, Max Planck Institute of Colloids and Interfaces, 14424 Potsdam, Germany.
authors.forename: Daniel
authors.initials: D
authors.lastname: Kolarich
authors.affiliation: Department of Medical Biochemistry and Cell Biology, Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, Sweden.
authors.forename: Niclas G
authors.initials: NG
authors.lastname: Karlsson
authors.affiliation: I3S - Instituto de Investigação e Inovação em Saúde, University of Porto, Portugal; Institute of Molecular Pathology and Immunology of the University of Porto - IPATIMUP, Porto, Portugal; Institute of Biomedical Sciences of Abel Salazar - ICBAS, University of Porto, Portugal; Medical Faculty, University of Porto, Portugal. Electronic address: celsor@ipatimup.pt.
authors.forename: Celso A
authors.initials: CA
authors.lastname: Reis
mesh_terms: D015971:Gene Expression Regulation, Enzymologic; D015972:Gene Expression Regulation, Neoplastic; D054794:Glycomics; D006801:Humans; D016256:Lewis X Antigen / Q000096:biosynthesis* / Q000235:genetics; D009363:Neoplasm Proteins / Q000096:biosynthesis* / Q000235:genetics; D011134:Polysaccharides / Q000096:biosynthesis* / Q000235:genetics; D020794:Receptor Protein-Tyrosine Kinases / Q000235:genetics / Q000378:metabolism*; D000080506:Sialyl Lewis X Antigen; D012799:Sialyltransferases / Q000096:biosynthesis / Q000235:genetics; D013274:Stomach Neoplasms / Q000235:genetics / Q000378:metabolism*; D000094663:beta-Galactoside alpha-2,3-Sialyltransferase
chemical_list: D016256:Lewis X Antigen; D009363:Neoplasm Proteins; D011134:Polysaccharides; D000080506:Sialyl Lewis X Antigen; D012799:Sialyltransferases; C080835:RON protein; D020794:Receptor Protein-Tyrosine Kinases; D000094663:beta-Galactoside alpha-2,3-Sialyltransferase; C000722087:ST3GAL1 protein, human
keywords: Gastric cancer; Glycome; RON; ST3GAL4; Sialome; Sialyl Lewis X (SLeX)