LECTIN-LIKE ACTIVITIES ASSOCIATED WITH HUMAN AND MURINE NEOPLASTIC-CELLS

  • 1 January 1981
    • journal article
    • research article
    • Vol. 41  (9) , 3642-3647
Abstract
Single-cell suspensions of several tumor cell lines, including 5 human melanomas (A375, SH4, Hs294, Hs852 and Hs939), a human cervical adenocarcinoma (HeLa-S3), a murine melanoma (B16-F1) and a murine fibrosarcoma (UV-2237P), undergo extensive homotypic aggregation in the presence of the glycoproteins fetuin and its desialated derivative, asialofetuin. This phenomenon was observed even at very low glycoprotein concentrations (< 10 .mu.g/ml). Fluorescent derivatives of fetuin and asialofetuin bind to the surface B16-F1 melanoma cells; this binding can be inhibited by lactose (0.1 M). Since the above results suggested the presence of a carbohydrate-binding component(s) on the tumor cells, the possibility that the cells contain endogenous lectin(s) was tested. Extracts prepared from the neoplastic cell lines used in this study exhibited a potent capacity to agglutinate trypsin-treated, glutaraldehyde-fixed rabbit erythrocytes. This activity was abolished by treating the extracts with trypsin and could be inhibited by millimolar concentrations of lactose, whereas D-galactose, D-galactosamine and N-acetyl-D-galactosamine were much less potent inhibitors. D-Mannose, L-fucose and N-acetyl-D-glucosamine failed to inhibit hemagglutination at 0.2 M. The presence of a galactoside-specific lectin in the tumor cells was demonstrated. The implications of the existence of a carbohydrate-binding protein(s) on the surface of malignant cells on their in vivo behavior, especially as it may relate to metastatic spread, are discussed.