Carcinogenesis in tissue culture 26: malignant transformation of rat liver cells in vitro associated with paradoxical electrokinetic changes.

Periodical examinations of the electrophoretic mobility of rat liver cells of two culture strains, RLC-10(2) and JTC-25.P3, were performed after the treatment with 3.3 X 10(-6) M 4-nitroquinoline 1-oxide (4NQO) for 30 min in culture. As early as 47th day after a single treatment with 4NQO, both control and treated cells of RLC-10(2) were found to produce tumors in animals on back-transplantation. At this stage, however, little difference was yet observed in electrokinetic patterns between the treated cells and the original antecedent cells. In contrast, a subline, JTC-25.P3, treated twice with 4NQO under the same conditions demonstrated a malignant electrokinetic pattern resembling that of rat ascites hepatocarcinoma strains, although its tumorigenicity was not verified. These discrepancies between changes of electrokinetic pattern and tumorigenicity were discussed with special references to the antigenic difference between cultured cell strains and each original host rats.