Glycomic analysis of gastric carcinoma cells discloses glycans as modulators of RON receptor tyrosine kinase activation in cancer

• Published in: Biochimica et biophysica acta Vol. 1860; no. 8; pp. 1795 - 1808
• Main Authors: Mereiter, Stefan, Magalhães, Ana, Adamczyk, Barbara, Jin, Chunsheng, Almeida, Andreia, Drici, Lylia, Ibáñez-Vea, Maria, Gomes, Catarina, Ferreira, José A., Afonso, Luis P., Santos, Lúcio L., Larsen, Martin R., Kolarich, Daniel, Karlsson, Niclas G., Reis, Celso A.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01-08-2016
• Subjects: Biochemistry & Molecular Biology; Biochemistry and Molecular Biology; Biofysik; Biokemi och molekylärbiologi; Biophysics; breast-cancer; c-met; colorectal-cancer; Gastric cancer; Gene Expression Regulation, Enzymologic; Gene Expression Regulation, Neoplastic; Glycome; Glycomics; Humans; in-vivo; invasive growth; Lewis X Antigen - biosynthesis; Lewis X Antigen - genetics; linked; n-acetylglucosaminyltransferase-iii; Neoplasm Proteins - biosynthesis; Neoplasm Proteins - genetics; next-generation; oligosaccharides; personalized medicine; Polysaccharides - biosynthesis; Polysaccharides - genetics; Receptor Protein-Tyrosine Kinases - genetics; Receptor Protein-Tyrosine Kinases - metabolism; RON; Sialome; Sialyl Lewis X (SLeX); Sialyltransferases - biosynthesis; Sialyltransferases - genetics; ST3GAL4; Stomach Neoplasms - genetics; Stomach Neoplasms - metabolism; structural-analysis; HILIC-FLD-UPLC; PLA; IHC; Glycome; PTM; RTK; SLeX; RON; Sialyl Lewis X (SLeX); SLea; ST3GAL4; GC; Gastric cancer; Sialome
• ISSN: 0304-4165; 0006-3002; 1872-8006
• DOI: 10.1016/j.bbagen.2015.12.016

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 (SLeX). SLeX overexpression is associated with tumor aggressive phenotype and patients' poor prognosis.
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.
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 SLeX and the concomitant activation. SLeX and RON co-expression was validated in gastric tumors.
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.
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.
•Expression of ST3GAL4 modulates sialylation and glycan size in cancer cells.•Modulation of sialylation impacts N-glycan branched structures.•47 increased sialylated proteins were identified in ST3GAL4 overexpressing cells.•Gastric cancer cells showed activation of aberrantly glycosylated RON receptor.•Aberrant RON glycosylation with SLeX was validated in human gastric tumors.