Glycosaminoglycan production and distribution in cloned B16 murine melanoma cell lines exhibiting different lung colony-forming efficiencies

Three cloned B16 murine melanoma cell lines were characterized with respect to their ability to a) detach from a plastic tissue culture substratum, b) form experimental pulmonary metastases, and c) produce and process glycosaminoglycans (GAGS). All three of the cell lines formed pulmonary metastases to different extents. Chondroitin sulfate and heparin-heparan sulfate were the major GAGS produced by all of the clones. Although the major compositional analyses of the cell lines were similar, some differences were apparent. The clone never selected for lung colony-forming efficiency and with the lowest metastatic potential (B16YL1) exhibited a reduced cell-associated glycosaminoglycan (GAG) matrix, shed the highest proportion of labeled GAGS into the medium, and was the most easily removed from the tissue culture substratum. In contrast, the other two cell lines (B16YM1 and B16YH1), derived from cultures selected for lung colony-forming efficiency, exhibited GAG-enriched cellular coats and were more resistant to EDTA-induced detachment from the plastic substratum. Both the B16YL1 and B16YM1 clones, which exhibited the lowest lung colony-forming efficiencies, shed an unsulfated chondroitin species into the extracellular fraction that was not evident in the most metastatic clone B16YH1. Despite these differences, cellular GAG matrix development and detachment from the plastic substratum showed only a partial correlation with lung colony-forming efficiency, presumably expressing the complexity of this biological phenomenon. Nonetheless, the findings suggest that GAGS may play an important role at several steps along the cascade of events leading to the successful dissemination of malignant cells.