Lack of correlation between the response to a proliferation inhibitor and other transformation markers in a mutant liver cell line.

A rat liver factor, which has been found previously to inhibit proliferation of untransformed rat liver cell lines but not of transformed liver cell lines, did not inhibit proliferation of the chemically transformed rat liver cell line, W-8. Moreover, a temperature-sensitive mutant derived from W-8 (TS-223), which exhibits an untransformed phenotype at 39.5-41 degrees and a transformed phenotype at 36 degrees, was not affected by the liver factor at either temperature. Since the factor can be incubated at 41 degrees for 4 days without loss of activity, it would seem that the regulation of cell proliferation is not necessarily linked with the expression of other markers of transformed cells.