title: 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.affiliation: Department of Clinical Science, University of Bristol, Bristol BS8 1TH, UK.
authors.forename: Georgios
authors.initials: G
authors.lastname: Patsos
authors.forename: Virginie
authors.initials: V
authors.lastname: Hebbe-Viton
authors.forename: Catherine
authors.initials: C
authors.lastname: Robbe-Masselot
authors.forename: David
authors.initials: D
authors.lastname: Masselot
authors.forename: Raul
authors.initials: R
authors.lastname: San Martin
authors.forename: Rosemary
authors.initials: R
authors.lastname: Greenwood
authors.forename: Christos
authors.initials: C
authors.lastname: Paraskeva
authors.forename: Andreas
authors.initials: A
authors.lastname: Klein
authors.forename: Monika
authors.initials: M
authors.lastname: Graessmann
authors.forename: Jean Claude
authors.initials: JC
authors.lastname: Michalski
authors.forename: Timothy
authors.initials: T
authors.lastname: Gallagher
authors.forename: Anthony
authors.initials: A
authors.lastname: Corfield
mesh_terms: D017209:Apoptosis / Q000187:drug effects*; D018938:Caco-2 Cells; D049109:Cell Proliferation / Q000187:drug effects*; D015179:Colorectal Neoplasms / Q000188:drug therapy* / Q000201:enzymology; D004354:Drug Screening Assays, Antitumor / Q000379:methods; D004791:Enzyme Inhibitors / Q000737:chemistry / Q000494:pharmacology*; D005690:Galactose / Q000031:analogs & derivatives* / Q000737:chemistry / Q000494:pharmacology; D006023:Glycoproteins / Q000378:metabolism*; D006031:Glycosylation / Q000187:drug effects; D016695:Glycosyltransferases / Q000037:antagonists & inhibitors*; D006801:Humans; D009363:Neoplasm Proteins / Q000378:metabolism*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods
chemical_list: C411946:1-benzyl-2-acetamido-2-galactopyranoside; D004791:Enzyme Inhibitors; D006023:Glycoproteins; D009363:Neoplasm Proteins; D016695:Glycosyltransferases; D005690:Galactose