Changes in surface properties of normal and transformed cells caused by tunicamycin, an inhibitor of protein glycosylation.

Abstract

Normal and virally transformed mouse (3T3) and human (WI-38) cells were treated with tunicamycin, an inhibitor of lipid-carrier-dependent glycosylation of rpoteins. Incubation of cells with tunicamycin (1 .mu.g/ml) caused detachment and death of sv-40- and polyoma-transformed cells within 24 h; these effects were not seen with nontransformed cell lines. The proliferation of 3T3 cells was inhibited by tunicamycin and, after a few days, a distinct change from an epithelioid to an abnormally elongated shape was observed. Both inhibition of growth and the morphological changes were reversible. A marked decrease in concanavalin A agglutinability was observed in virally transformed cells treated with tunicamycin (0.5 .mu.g/ml), but agglutination by wheat germ agglutinin or soybean agglutinin was unaffected. Analysis of biosynthetically labeled proteins showed that a high MW protein, presumed to be related to fibronectin, is markedly reduced in the medium of cells cultured in the presence of tunicamycin. Tunicamycin probably interfers with the insertion or function of 1 or more cell-surface glycoproteins. Such cell-surface changes could affect a number of cellular properties, including attachment, cell shape and agglutinability by some lectins.