Glycobiology Advance Access published online on January 3, 2009
Glycobiology, doi:10.1093/glycob/cwn149
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O-GLYCAN INHIBITORS GENERATE ARYL-GLYCANS INDUCE APOPTOSIS AND LEAD TO GROWTH INHIBITION IN COLORECTAL CANCER CELL LINES
1 From the Departments of Clinical Science at South Bristol
2 Chemistry
3 Cellular and Molecular Medicine, University of Bristol, Bristol UK
4 Institut für Molekularbiologie und Bioinformatik, Charité Unversitätsmedizin Berlin, Arnimallee 22, 14195 Berlin, Germany
5 UMR CNRS /USTL 8576, "Glycobiologie Structurale et Fonctionnelle", Bâtiment C9, Université des Sciences et Technologies Lille1, F-59655 Villeneuve d'Ascq Cedex France
Address correspondence to: Anthony Corfield, Mucin Research Group, Clinical Science at South Bristol, Bristol Royal Infirmary, Level 7, Marlborough Street, Bristol BS2 8 HW, UK. Tel: 44–117-928–4898; FAX 44–925-2736; Email: tony.corfield{at}bristol.ac.uk
Received on June 30, 2008; accepted on December 13, 2008
Our studies provide direct evidence that O-glycosylation pathways play a role in the regulation of cell growth through apoptosis and proliferation pathways. A series of small molecular weight analogues of the GalNAc-
-1-O-serine/threonine structure based on 1-benzyl-2-acetamido-2-deoxy--O-D-galactopyranoside have been synthesised and tested in the human colorectal cancer cell lines PC/AA/C1/SB10 C and HCA7/C29. Three inhibitors, 1-benzyl-2-acetamido-2-deoxy--O-D-galactopyranoside and the corresponding 2-azido- and C-glycoside analogues were screened in these colorectal cancer cell lines at 0.5 mM and showed induction of apoptosis and down regulation of proliferation. Treatment both cell lines with inhibitors led to changes in glycosylation detected with peanut lectin. Inhibition of glycosyltransferase activity in cell homogenates from human colorectal mucosal cells and cultured cell lines could be shown. The competitive action of the inhibitors resulted in the intracellular formation of 28 aryl-glycan products which were identified by MALDI and electrospray mass spectroscopy. The structures showed a differential pattern for each of the inhibitors in both cell lines. Gene array analysis of the glycogenes illustrated a pattern of glycosyltransferases that matched the glycan structures found in glycoproteins and aryl-glycans formed in the PC/AA/C1/SB10 C cells, however there was no action of the three inhibitors on glycogene transcript levels. The inhibitors act at both intermediary metabolic and genomic levels, resulting in altered protein glycosylation and aryl-glycan formation. These events may play a part in growth arrest.
Key words: Apoptosis / Aryl-glycans Benzyl-O-GalNAc / Growth Inhibition / O-Glycans
Current address: Department of Organic Chemistry II, Faculty of Science and Technology, University of the Basque Country (UPV/EHU), Leioako Kanpusa. Sarriena auzoa, z/g. 48940 Leioa (Bizkaia) Spain