Ethanol. A heat sensitizer on neuroblastoma cells in culture

The presence of 1% ethanol in culture medium during heat treatment (40 degrees C for 8 hours and 43 degrees C for 15 minutes) was sufficient to enhance the effect of hyperthermia on murine neuroblastoma cells (NBP2) in culture, on the criteria of growth (number of viable cells per dish) and survival (colony formation). However, the metabolites of ethanol, acetaldehyde, and sodium acetate at concentrations of 0.003% and 0.125% in culture medium, respectively, under the same experimental conditions did not modify the effect of heat (40 degrees C) on these cells. The presence of same concentration of ethanol, acetaldehyde, or sodium acetate for 15 minutes or 8 hours at 37 degrees C did not affect the growth or the survival of NB cells in culture. These results suggest that ethanol itself rather than its metabolites is responsible for the enhancement of heat effect on NB cells. When ethanol and its metabolites were allowed to remain in the culture medium for the entire periods of heat treatment and observation, they also enhanced the effects of heat on NB cells; however, acetaldehyde was more effective.