Comparison of the cytotoxicity of 5-thio-D-glucose and misonidazole on hypoxic cells in vitro.

The cytotoxicity of 5-thio-D-glucose (5-TG) and misonidazole (MISO) on hypoxic cells in vitro was compared, and the combined effect of these two compounds was investigated. The cytotoxicity of 5-TG on hypoxic SCK mammary carcinoma cells of mice was markedly greater than that of MISO. However, MISO was more toxic than was 5-TG to P815-X2 mastocytoma cells of mice. The elevation of temperature from 37.5 degrees C to 40.0 degrees C during incubation with drugs greatly enhanced the cell death. The thermal enhancement of cytotoxicity of 5-TG to mastocytoma cells appeared to be greater than that of MISO. Preliminary studies indicated that the combined effect of 5-TG and MISO is additive, suggesting the intracellular targets or cytocidal mechanisms of these two compounds may be different.