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Alteration of lacto‐series glycolipid glycosyltransferase activities in human colonic adenocarcinoma DLD‐1 cells after culture in N , N ‐dimethylformamide‐containing medium
Author(s) -
Holmes Eric H.,
Greene Thomas G.
Publication year - 1990
Publication title -
journal of cellular biochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.028
H-Index - 165
eISSN - 1097-4644
pISSN - 0730-2312
DOI - 10.1002/jcb.240440204
Subject(s) - glycolipid , chemistry , glycosyltransferase , antigen , dimethylformamide , biochemistry , microbiology and biotechnology , monoclonal antibody , lactosylceramide , ganglioside , enzyme , antibody , biology , immunology , solvent
Human colonic adenocarcinoma DLD‐1 cells were grown under conditions which induce characteristics of differentiated cells using medium containing 0.8% N , N ‐dimethylformamide in order to study alterations in glycosphingolipid glycosyltransferase activities during this process. Analysis of biosynthetic reactions involved in lacto‐series antigen synthesis revealed no changes in the specific activities of either β1→4galactosyltransferase or α1→3/4fucosyltransferase with N , N ‐dimethylformamide treatment. However, a dramatic decrease of from 14‐ to 20‐fold in the β1→3 N ‐acetylglucosaminyltransferase activity was observed in the treated cells. This enzyme catalyzes the rate‐limiting step in lacto‐series core chain synthesis. This is consistent with the pattern of regulation of lacto‐series antigen expression found to occur during oncogenesis in human colonic mucosa (Holmes EH, Hakomori S, Ostrander GK: J Biol Chem 262:15649, 1987). Total glycolipids from untreated and N , N ‐dimethylformamide‐treated cells were isolated and subjected to TLC immunostain analysis and solid phase radioimmunoassay with a series of monoclonal antibodies specific for lacto‐series‐based carbohydrate antigens. A decrease of about 2‐fold or less in the quantity of lacto‐series antigens was observed as a consequence of N , N ‐dimethylformamide treatment in both neutral glycolipid and ganglioside fractions. The results suggest that only very low levels of β1→3 N ‐acetylglucosaminyltransferase activity are required for the steady state expression of significant levels of lacto‐series based glycolipids and that modulation of its activity levels by N , N ‐dimethylformamide treatment in DLD‐1 cells represents a convenient in vitro system for studying aspects of regulation of lacto‐series antigen expression.