Radiosensitizing effect of 2,4-dinitroimidazole-1-ethanol and its cytotoxicity in HeLa S3 cells.

Using cultured HeLa S3 cells, the radiosensitizing and cytotoxic effects of newly synthesized derivatives of dinitroimidazole were investigated and compared with those of misonidazole. 2,4-Dinitroimidazole-1-ethanol radiosensitized hypoxic cells selectively. At 5 mM misonidazole, the enhancement ratio was 1.95; with 0.5 mM 2,4-dinitroimidazole-1-ethanol, almost the same enhancement could be obtained. This indicates that the radiosensitizing effect of the latter agent was about 10 times greater than that of misonidazole. However, its cytotoxicity was twice that of misonidazole under hypoxic conditions and there was no apparent differential cytotoxicity to hypoxic and aerobic cells.