Synthesis and release of cell surface-derived and sulfated lactosaminoglycans by human ovarian carcinoma cells

Ovarian carcinoma cell clusters were isolated from patient effusions. Cell-surface glycoconjugates were radiolabelled by a galactose oxidase-borotritide method. The surface-labelled glycoconjugates and metabolically labelled glycoconjugates released to culture medium were characterized. The surface-derived glycoconjugates were highly heterodisperse and had the same molecular weight distribution as the metabolically labelled components. Lectin precipitation assays showed that both classes of glycoconjugates contained N-linked oligosaccharides bearing N-acetyllactosamine moieties. A121 ovarian carcinoma cells also synthesized and released a heterodisperse array of glycoconjugates to culture medium. Ricinus communis agglutinin I (RCAI) precipitated glycoconjugates of MW greater than 100 kDa for both A121 cells and cells from effusions. Cells of different ovarian carcinoma histology yielded similar results. Metabolic labelling experiments with 35SO4 showed that the RACI-bound glycoconjugates released by A121 cells were sulfated. The RCAI-bound sulfated lactosaminoglycans may be associated with malignant transformation and/or metastasis since similar components were not produced by mesothelial cells isolated from effusions [Allen, H.J., M. Gamarra M.S. Piver and E.A.Z. Johnson (1989). Cancer Biochem. Biophys. 10, 219-226].