Temperature effect on mitoxantrone cytotoxicity in Chinese hamster cells in vitro

The effect of heat on 1,4-dihydroxy-5,8-bis[2-[(2-hydroxyethyl)amino]ethylamino]-9, 10-anthracenedione dihydrochloride (DHAD; mitoxantrone, NSC 301739) cytotoxicity was studied in V79 Chinese hamster cells. An overnight exposure to the drug at 40 degrees C enhanced drug damage in chromosome aberrations, culture growth, and cellular reproductive integrity. Preincubation of cells overnight in medium containing no drug at this temperature also showed some enhancement in subsequent DHAD lethality (at 37 degrees C as well as 43 degrees C). Short exposures (1 h) to DHAD at 43 degrees C was more damaging than were exposures at 37 degrees C. This was also true for cells in the plateau phase of culture growth. As compared with exponentially growing cells, plateau-phase cells were more resistant to DHAD.