Isolation and characterization of an N-linked oligosaccharide that is increased in glioblastoma tissue and cell lines.

We have isolated and characterized N-linked oligo-saccharides that are significantly increased in glioblastoma tissue and cell lines. The structures of N-linked oligosaccharides present in 3 human normal brain tissues, 15 patients with glio-blastoma and 3 glioma cell lines were analyzed by partially automated technique for the isolation and fluorescent labeling of N-linked sugar chains from glycoproteins. Characterization of the sugar chains was achieved with the use of a combination of HPLC columns and a highly sensitive fluorescence detector at femtomole levels. By collecting peaks which accounted for 0.1% or more, sixteen different oligosaccharide structures were characterized from glioblastoma tissue and cell lines. The 16 oligosaccharide structures accounted for 48.9% of the total N-linked oligosaccharides present in glioblastoma tissue. The major components of total oligosaccharides were similar to those of normal brain tissue. The amount of a biantennary bigalactosylated structure with one core fucosylation (A2G2F) was present in increased levels in glioblastoma tissue (mean = 2.90%) and glioma cell lines (mean = 5.60%), while being less than 0.1% in normal brain tissue. Expression of highly branched tetra-antennary N-glycans that are usually detected in lungs or hepatocellular cancer was not observed. Tissue glioma cells and cultured cells also displayed strong LCA-lectin binding, which binds to sugar chains with core fucose (including A2G2F), while normal brain tissue did not. Moreover, LCA lectin inhibited proliferation of glioma cells through induction of apoptosis. A2G2F on glioma specimens may provide a novel marker and target for the diagnosis and treatment of glioblastoma, respectively.