ISSN:
1573-4986
Keywords:
HT-29 cells
;
mucins
;
aryl-glycosides
;
O-glycosylation
;
sialyltransferases
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
Notes:
Abstract We have analysed the mucins synthesized by the HT-29 MTX cell subpopulation, derived from the HT-29 human colon carcinoma cells through a selective pressure with methotrexate (Lesuffleuret al., 1990,Cancer Res 50: 6334–43), in the presence of benzyl-N-acetyl-α-galactosaminide (GalNAcα-O-benzyl), which is a potential competitive inhibitor of the β1,3-galactosyltransferase that synthesizes the T-antigen. The main observation was a 13-fold decrease in the sialic acid content of mucins after 24 h of exposure to 5mm GalNAcα-O-benzyl. This effect was accompanied by an increased reactivity of these mucins to peanut lectin, testifying to the higher amount of T-antigen. The second observation was a decrease in the secretion of the mucins by GalNAcα-O-benzyl treated cells. The decrease in mucin sialyation was achieved through thein situ β-galactosylation of GalNAcα-O-benzyl into Galβ1–3GalNAcα-O-benzyl, which acts as a competitive substrate of Galβ1–3GalNAc α2,3-sialyltransferase, as shown by the intracellular accumulation of NeuAcα2–3Galβ1–3GalNAcα-O-benzyl in treated cells.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00702335
