Oncogenic transformation in vitro by the hypoxic cell sensitizer misonidazole.

The hypoxic cell sensitizer Misonidazole (Ro-07-0582) induces oncogenic transformations in the C3H/10T1/2 mouse embryo cell line cultured in vitro. A drug concentration of 0.4 mM applied to aerated cells for 3 or 6 days results in a transformation rate comparable to that observed following an X-ray dose of 1 Gray. A higher drug concentration of 6.0 mM is equivalent to 4 Gy. The combination of Misonidazole and X-rays produces a significant increase in the frequency of transformation over either drug or radiation alone, but the data are equivocal on the question of additivity vs synergism.