O-glycan inhibitors generate aryl-glycans, induce apoptosis and lead to growth inhibition in colorectal cancer cell lines.

Abstract

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 analogs of the GalNAc-alpha-1-O-serine/threonine structure based on 1-benzyl-2-acetamido-2-deoxy-alpha-O-d-galactopyranoside have been synthesized and tested in the human colorectal cancer cell lines PC/AA/C1/SB10C and HCA7/C29. Three inhibitors, 1-benzyl-2-acetamido-2-deoxy-alpha-O-D-galactopyranoside, and the corresponding 2-azido- and C-glycoside analogs were screened in these colorectal cancer cell lines at 0.5 mM and showed induction of apoptosis and downregulation of proliferation. Treatment of both cell lines with inhibitors led to changes in glycosylation detected with peanut lectin. The 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/SB10C 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.

• Authors: Georgios Patsos, Virginie Hebbe-Viton, Catherine Robbe-Masselot, David Masselot, Raul San Martin, Rosemary Greenwood, Christos Paraskeva, Andreas Klein, Monika Graessmann, Jean Claude Michalski, Timothy Gallagher, Anthony Corfield
• Journal: Glycobiology (Glycobiology) Vol. 19 Issue 4 Pg. 382-98 (Apr 2009) ISSN: 1460-2423 [Electronic] England
• PMID: 19122213 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• 1-benzyl-2-acetamido-2-galactopyranoside
• Enzyme Inhibitors
• Glycoproteins
• Neoplasm Proteins
• Glycosyltransferases
• Galactose

Topics

• Apoptosis (drug effects)
• Caco-2 Cells
• Cell Proliferation (drug effects)
• Colorectal Neoplasms (drug therapy, enzymology)
• Drug Screening Assays, Antitumor (methods)
• Enzyme Inhibitors (chemistry, pharmacology)
• Galactose (analogs & derivatives, chemistry, pharmacology)
• Glycoproteins (metabolism)
• Glycosylation (drug effects)
• Glycosyltransferases (antagonists & inhibitors)
• Humans
• Neoplasm Proteins (metabolism)
• Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization (methods)