Studies on glycoproteins produced by wild type and wheat germ agglutinin-resistant B16 mouse melanoma cells

Two variants of B16 mouse melanoma cells have been selected in serum-free medium for their resistance to toxic levels of wheat germ agglutinin isolation 1 (WGA). Chromosome analysis and characteristic melanin production showed that the variants are derived from the parent mouse melanoma cell lines. However, the two variants were less tumorigenic in mice compared to the parent B16 mouse melanoma cells. The variants showed a marked decrease in cell agglutination with WGA. Cell agglutination with recin and peanut lectin was not different between the three cell lines, but the two variants showed a slight increase in agglutination with concanavalin A. The binding of 125I-labeled wheat germ agglutinin to the two variant cells was reduced compared to that of the parent cell. Glycoproteins secreted or shed by the three lines were isolated after growth in serum-free medium in the presence of [3He]glucosamine and bovine serum albumin (1%). These metabolically labeled products were fractionated on the basis of their interaction with WGA-Sepharose (2 mg/ml). The WGA-Sepharose affinity chromatographic data suggested a decrease in WGA-binding glycoprotein(s) secreted to the medium by the two variants. The WGA-bound glycoproteins from the two variants upon SDS-PAGE revealed three bands of approximate molecular weights, 92,000, 56,000, and 42,000, none of which were present in the parent cell line (50,000 molecular weight)