Alteration of lacto-series glycolipid glycosyltransferase activities in human colonic adenocarcinoma DLD-1 cells after culture in N,N-dimethylformamide-containing medium.
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 beta 1----4galactosyltransferase or alpha 1----3/4fucosyltransferase with N,N-dimethylformamide treatment. However, a dramatic decrease of from 14- to 20-fold in the beta 1----3N-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 beta 1----3N-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.
Holmes
E H
EH
Pacific Northwest Research Foundation, Seattle, Washington 98122.
Greene
T G
TG
D000230:Adenocarcinoma / Q000473:pathology*; D000951:Antigens, Neoplasm / Q000096:biosynthesis*; D002454:Cell Differentiation / Q000187:drug effects; D002471:Cell Transformation, Neoplastic; D003110:Colonic Neoplasms / Q000473:pathology*; D004126:Dimethylformamide / Q000494:pharmacology*; D006017:Glycolipids / Q000378:metabolism*; D006031:Glycosylation; D006602:Hexosyltransferases / Q000032:analysis*; D006801:Humans; D009363:Neoplasm Proteins / Q000032:analysis*; D014407:Tumor Cells, Cultured / Q000187:drug effects / Q000201:enzymology / Q000473:pathology
D000951:Antigens, Neoplasm; D006017:Glycolipids; D009363:Neoplasm Proteins; D004126:Dimethylformamide; D006602:Hexosyltransferases