title: Specific modifications of hepatoma cell-surface glycoproteins with enzymes. Effects on in vitro growth as investigated by the use of lectins.
abstract: The effects of enzymic treatment on the interactions between Zajdela's tumor cells and various lectins. Concanavalin A (ConA); Wheat Germ Agglutinin (WGA); Robinia lectin; have been studied. (1) The number of lectin-binding sites and the affinity constants were investigated. (2) The effects of the lectins on cell growth and [3H]thymidine incorporation were studied on untreated and enzyme-treated cells. It was observed that treatment of tumor cells with neuraminidase resulted in a change in the binding characteristics of each lectin. However, additional treatment of the cells with galactose oxidase had no further effect on lectin binding. ConA and Robinia lectin induced a decrease of the untreated tumor cell growth and a stimulation of the [3H]thymidine incorporation. This paradoxal result may be explained as a consequence of the stimulation of the [3H]thymidine uptake observed in the presence of lectins. The enzymatic treatments themselves did not change the cell growth although they did induce a change in the effect of ConA and Robinia lectin on cell growth and [3H]thymidine incorporation. As a result of neuraminidase treatment, the effects of ConA were totally suppressed but those of Robinia lectin only partially. Although WGA interacted with untreated and enzyme-treated cell surfaces, it had no effect on tumor cell growth nor [3H]thymidine incorporation. The results are discussed in terms of lectin transport.
mesh_terms: D000818:Animals; D001667:Binding, Competitive; D002455:Cell Division / Q000187:drug effects; D005692:Galactose Oxidase / Q000494:pharmacology; D037102:Lectins / Q000494:pharmacology*; D008114:Liver Neoplasms, Experimental / Q000378:metabolism* / Q000473:pathology; D008562:Membrane Glycoproteins / Q000378:metabolism*; D019158:N-Acetylneuraminic Acid; D009439:Neuraminidase / Q000494:pharmacology; D051381:Rats; D012794:Sialic Acids / Q000378:metabolism; D013936:Thymidine; D014407:Tumor Cells, Cultured
chemical_list: D037102:Lectins; D008562:Membrane Glycoproteins; D012794:Sialic Acids; D005692:Galactose Oxidase; D009439:Neuraminidase; D019158:N-Acetylneuraminic Acid; D013936:Thymidine