Calcium-mediated changes in related malignant and nonmalignant mouse epidermal cell lines.

Two epidermal cell lines of common origin, one tumorigenic and the other not, have been grown in media of different Ca2+ concentrations (low: 0.07 mM; normal: 1.4 mM; high: 10 mM). At normal Ca2+ levels, both cell lines had similar growth rates. The growth rates were reduced at both higher and lower Ca2+ concentrations, with greater inhibition of the tumorigenic than the nontumorigenic cells. At a given level of Ca2+, the 2 cell lines could not be distinguished in their polyacrylamide gel patterns by protein staining, by [125I]concanavalin A reactivity, and by lactoperoxidase iodination. Changes in surface membrane proteins with Ca2+ concentrations were observed by lactoperoxidase iodination, whereas the other techniques, which measure total cell proteins or glycoproteins, showed no substantial variation.