Responses of mouse cell lines transformed by various means to histidinol/cytosine arabinoside treatment.

The responses of the phenotypically-normal BALB/c 3T3 mouse cell line A31 and three of its transformed derivatives, BP-A31 (a benzo(a)pyrene transformant), M-A31 and SV-A31 (Moloney murine sarcomavirus and SV-40 virus transformants, respectively) to L-histidinol and to L-histidinol/cytosine arabinoside (AraC) combinations were investigated. As observed in comparable studies with other normal cell lines, prior treatment of the A31 parental line with L-histidinol led to significant protection from AraC-mediated toxicity. However, in contrast to previous analyses of a number of other transformed cell lines which showed enhanced AraC-mediated toxicity upon prior exposure to L-histidinol, the three types of A31 transformants were afforded varying degrees of protection from AraC when treated with histidinol. These findings support the concept that transformed, tumorigenic cells may retain certain growth properties of their nontumorigenic parental cells.