INCREASED EXPRESSION OF HIGHLY BRANCHED N-GLYCANS AT CELL-SURFACE IS CORRELATED WITH THE MALIGNANT PHENOTYPES OF MOUSE-TUMOR CELLS

Three NIH3T3 transformants, MTAg, MTPy, and MTI, which grow similarly in soft agar media, showed remarkable differences in athymic mice: MTA g grew more rapidly than MTPy, whereas MT1 and NIH3T3 did not, and onl y MTAg metastasized in lung, Structural analysis of N-glycans from pla sma membrane glycoproteins revealed that each sample contains similar amounts of N-glycans, but the relative amounts of 2,6-branched tri- an d tetra-antennary oligosaccharides prominently increase and the relati ve amounts of biantennary oligosaccharides prominently decrease in the order of NIH3T3, MT1, MTPy, and MTAg whereas those of others remained constant. Western blot analysis revealed that binding of Datura stram onium agglutinin, which interacts with 2,6-branched tri- and tetra-ant ennary oligosaccharides, is significantly increased in several bands f rom MTAg compared with NIH3T3, two of which are tentatively identified as lysosome-associated membrane protein-1 and fibronectin (FN)-recept or. It was also shown that the spreading of MTAg on FN-coated plates i s dramatically inhibited with the anti-FN; receptor antiserum when com pared with NIH3T3. These results indicate that the increased expressio n of highly branched N-glycans at cell surface is correlated with the rapidness of tumor formation and altered adhesive properties of tumor cells in vivo.