Glycoproteins of cultured epithelial cells from human colonic adenocarcinoma and fetal intestine

Abstract

The molecular weight distribution and Concanavalin A binding properties of labeled glycopeptides and glycoproteins from cell surface membranes, the cytoplasmic fraction and culture media were studied in human fetal and neoplastic colonic cells. Cells were labeled by culturing cells in the presence of [ 14C]-or[ 3 H]-labeled glucosamine or fucose. Both fucose and glucosamine were incorporated into the membrane glycoprotein fraction of the colonic cancer cells to a much lesser extent than into fetal cells. The elution profile obtained from Bio-gel P- 150 column chromatography indicated that colonic cancer cell membranes contain fucose- and glucosamine-labeled, trypsin labile, high molecular weight glycopeptides not present in fetal cells. Affinity chromatographic studies of membrane glycopeptides using agarose-bound Concanavalin A also indicated that cell surface membranes from fetal and cancerous colonic cells contain not only glycoproteins of different molecular weights, but glycoproteins having different oligosaccharide side chains. These results indicate that there are significant quantitative and qualitative differences in cell surface glycoproteins between fetal and cancerous intestinal cells.