Comparison of the effects of dihydroxyanthraquinone and adriamycin on the survival of cultured Chinese hamster cells.

Dihydroxyanthraquinone [1,4-dihydroxy-5,8-bis ((2-([(2-hydroxyethyl)amino)ethyl)amino))-9,10-anthracenedione (DHAQ) (NSC 279836)] is currently being tested as a cancer chemotherapeutic agent because of its structural similarity to Adriamycin (ADR) and other DNA-intercalating antibiotics. We have therefore studied the effect of DHAQ on the survival of cultured Chinese hamster cells in direct comparison to ADR. Both DHAQ and ADR produced cytotoxicity that was dependent upon the concentration and duration of drug exposure. For 1-hr pulse exposures of asynchronous populations of exponentially growing cells, a 5- to 10-fold greater concentration of ADR than of DHAQ was required to produce the same level of cell killing. There were also differences in the cell cycle age specificity demonstrated by treating at various times before or after selection of cells in mitosis. DHAQ produced the greatest cytotoxicity in cells treated while in G1 or G2; ADR was more effective on cells located in S phase or mitosis. Overall, DHAQ was found to be similar to ADR and other DNA-intercalating antibiotics with regard to the induction of cell lethality. The only differences were those of the concentration required to produce a certain level of effect and of the cell cycle phase specificities for maximum effect.