Surface properties of normal, transformed, and temperature-sensitive rat liver epithelial cells

Cell surface proteins, glycoproteins, and glycopeptides from normal, transformed, and mutant temperature-sensitive rat liver epithelial cells were radiolabeled and compared by Sephadex G-50 chromatography and polyacrylamide gel electrophoresis. Some changes were observed in the transformed cell lines including an increase in high-molecular-weight glycopeptides and a decrease in the amount of fibronectin (large external transformation-sensitive) protein. The mutant TS223 cells, which were temperature-sensitive for maintenance of the transformed phenotype when grown at the nonpermissive temperature (41 degrees C), had characteristics intermediate between those of the normal and transformed phenotypes. These results corresponded to those of previous studies indicating that TS223 was somewhat "leaky" at 41 degrees C; i.e., although more "normal" than at 37 degrees C, it was not completely normal. Alterations in surface macromolecules in transformed epithelial cells may, therefore, represent a useful marker for transformation because morphologic changes are usually not readily apparent in transformed epithelial cells.