title: Asparagine-linked oligosaccharides in murine tumor cells: comparison of a WGA-resistant (WGAr) nonmetastatic mutant and a related WGA-sensitive (WGAs) metastatic line.
abstract: MDW40, a wheat germ agglutinin-resistant (WGAr) mutant of the highly metastatic tumor cell line called MDAY-D2, is restricted to local growth at the subcutaneous site of inoculation. The WGAr tumor cells acquire metastatic ability by fusing spontaneously with a normal host cell followed by chromosome segregation, a process accompanied by reversion of the WGAr phenotype (i.e., WGAs). Since lectin-resistant mutant cell lines often have oligosaccharide alterations that may affect membrane function and consequently metastatic capacity, we compared the major Asn-linked glycopeptides in WGAr and WGAs cell lines. [2-3H]mannose-labeled glycopeptides were separated into four fractions on a DEAE-cellulose column and then further fractionated on a concanavalin A-Sepharose column. Glycopeptide structures were determined by: (a) sequential exoglycosidase digestion followed by chromatography on lectin/agarose and Bio-Gel P-4 columns and (b) proton nuclear magnetic resonance analysis. The metastatic WGAs cells had a sialylated poly-N-acetyllactosamine-containing glycopeptide which was absent in the nonmetastatic mutant cell line. Unique to the mutant was a neutral triantennary class of glycopeptide lacking sialic acid and galactose; the WGAr lesion therefore appeared to be a premature truncation of the antennae of the poly-N-acetyllactosamine-containing glycopeptide found in the WGAs cells. High mannose glycopeptides containing five to nine mannose residues constituted a major class in both WGAr and WGAs cells. Lysates of both wild-type and mutant cells had similar levels of galactosyltransferase activity capable of adding galactose to the N-acetylglucosamine-terminated glycopeptide isolated from mutant cells; the basis of the WGAr lesion remains to be determined.
mesh_terms: D000818:Animals; D001216:Asparagine; D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D002460:Cell Line; D004351:Drug Resistance; D006020:Glycopeptides / Q000302:isolation & purification; D006023:Glycoproteins / Q000302:isolation & purification*; D037102:Lectins; D008545:Melanoma / Q000473:pathology*; D051379:Mice; D008811:Mice, Inbred DBA; D009154:Mutation; D009362:Neoplasm Metastasis / Q000473:pathology*; D009844:Oligosaccharides / Q000032:analysis*; D014909:Wheat Germ Agglutinins
chemical_list: D006020:Glycopeptides; D006023:Glycoproteins; D037102:Lectins; D009844:Oligosaccharides; D014909:Wheat Germ Agglutinins; D001216:Asparagine