l-β-D-Arabinofuranosylcytosine-induced Malignant Transformation of Hamster and Rat Cells in Culture

The potent antileukemic chemotherapeutic drug, 1-β-d-arabinofuranosylcytosine (ara-C), was observed to transform malignantly secondary hamster fetal cells as well as established rat cells in vitro. Results indicated that: (a) hamster cells altered by treatment with ara-C are morphologically indistinguishable from cells transformed with benzo(a)pyrene; (b) the ara-C-induced transformation can be observed under conditions of little or no inhibition of DNA synthesis and little or no cytotoxicity; (c) the transformation can occur with only a 6-hr exposure to ara-C; and (d) the transformation of hamster cells seems to require cellular DNA synthesis, for cells in S phase are much more sensitive to ara-C-induced transformation than are G r arrested cells. Representative transformed colonies of hamster and rat cells produced rapidly growing fibrosarcomas in inoculated newborn hamsters and rats, respectively. Control cells remained nontumorigenic.