Effect of dihydroxyanthraquinone and radiation on G2 progression.

The effect of dihydroxyanthraquinone (DHAQ), a potential anticancer chemotherapeutic agent, on the progression of Chinese hamster ovary cells into mitosis and on the division delay induced by ionizing radiation was studied using the mitotic selection procedure for cell cycle analysis. Following the addition of DHAQ, the number of mitotic cells selected from an asynchronous population remained unaltered for a refractory period and then decreased. This effect was concentration dependent with transition points between the S/G2 boundary at 10(-4) micrograms/ml and the G2/M boundary at greater than or equal to 10(2) micrograms/ml. The duration of the transient division delay was dependent upon the concentration of drug used and the duration of pulse exposure. When cells were treated with pulses of DHAQ in addition to X-irradiation, there was no change in the location of the radiation transition point. There was an increase in the duration of division delay compared to that produced by X-ray alone that was dependent upon the concentration and duration of drug treatment. The effect of DHAW is similar to that of other cancer chemotherapeutic agents (Adriamycin, bleomycin, and lucanthone), and the same cautions should therefore be considered when combining DHAQ and radiation for clinical use.