The relationship between membrane permeability to adriamycin and adriamycin cytotoxicity in CHO cells at elevated temperatures.

The cytotoxicity of adriamycin at elevated temperatures was studied in CHO cells in vitro using a clonogenic assay. There is a significant increase in the cytotoxicity of adriamycin at temperatures which are not lethal to mammalian cells (38 degrees C-42 degrees C). The uptake of [14C]adriamycin was studied in similar conditions to determine whether the thermal enhancement of adriamycin cytotoxicity was due to an increase in membrane permeability. Although measurable increases in adriamycin uptake occur in the elevated but non-lethal temperature range, they are insufficient to explain the observed increase in cytotoxicity.