Transformation parameters induced in chick cells by incubation in media of altered NaCl concentration

Lowering the NaCl concentration of the medium in which normal chick cell cultures are incubated causes them to enlarge, vaculate, and appear morphologically similar to cells transformed by the Bryan strain of Rous sarcoma virus (RSV). Raising the NaCl concentration of the medium causes cells to become round or spindle shaped and to appear morphologically similar to cells transformed by the Schmidt-Ruppin strain of RSV. Uninfected chick cell cultures incubated in either low or high NaCl medium also express many characteristics of transformed cells. They lose contact inhibition of growth and movement, grow to higher saturation densities, synthesize reduced amounts of fibronectin, exhibit increased lectin agglutinability, transport increased amounts of hexoses, have reduced levels of succinic dehydrogenase activity, produce increased amounts of lactate and pyruvate, and can be serially passaged in culture significantly longer than normal chick fibroblasts. We were not able to induce normal chick cells to exhibit all transformation parameters by incubation an altered NaCl media: the cells did not grow in soft agar or in low serum medium. Cells transformed by the Bryan and Schmidt-Ruppin strains of RSV exhibit strain-specific changes in their intracellular Na⁺ and K⁺ concentrations. Cells incubated in altered NaCl media exhibit altered intracellular monovalent cation concentrations similar to those seen in the cells they resemble morphologically. Results presented in this publication identify a possible new transformation parameter, alteration of the intracellular Na⁺ and K⁺ concentrations, and suggest that many, but not all transformation parameters may be consequences of the altered intracellular monovalent cation concentrations.