Synthesis of type 1 and 2 lacto series glycolipid antigens in human colonic adenocarcinoma and derived cell lines is due to activation of a normally unexpressed beta 1----3N-acetylglucosaminyltransferase.

摘要: Abstract Human colonic adenocarcinoma tissue and derived cell lines have been characterized by an abundance of different type 1 2 lacto series glycolipid antigens which are either low or not found in normal mucosa. The enzymatic basis for the expression contrasting compositions between adenocarcinomas mucosa, as well lines, has studied. following results were particular interest. (i) Abundant activities beta 1----4galactosyltransferase associated with synthesis both lactosylceramide lactoneotetraosylceramide, 1----3galactosyltransferase lactotetraosylceramide, alpha 1----3/4fucosyltransferase responsible Lex Lea mucosa a mucosal epithelial line HCMC, both. Variable levels these tissues various established lines. In striking contrast, significant activity 1----3N-acetylglucosaminyltransferase lactotriaosylceramide (Lc3) was cases but undetectable cells. (ii) situ transfer galactose to Lc3 performed on histologic sections preincubation acceptor followed incubation UDP-galactose. biosynthesized revealed indirect immunofluorescence monoclonal antibody 1B2 defines lactoneotetraosylceramide antigen. studies, prepared from frozen proximal colon shown lack native chain structures. However, UDP-galactose could be demonstrated cells after incorporation into membranes, indicating ability synthesize core structures if precursor is available. showed antibody. These data suggest that accumulation glycolipids 1----3- 1----4fucosyl substitution human due enhanced rather than enhancement other enzymes. This enzyme may play key role regulating level types tumor-associated chain.