Multiparameter assessment of the cell cycle effects of bioactive and cytotoxic agents

This paper describes the use of the bromodeoxyuridine/propidium iodide method to assess the effects of bioactive and cytotoxic agents on the kinetic characteristics of acute myelogenous leukemia cells. By careful selection of gates, the following parameters can be measured simultaneously using only 50,000 cells: the proportion of cells in S-phase, the distribution of cells within the S-phase compartment, the relative rate of DNA synthesis, the relative distribution of S-phase times, the proportion of S0 cells, and the proportion of cells in G1 and G2/M. This method was used to demonstrate that while retinoic acid, alpha-interferon, and cytosine arabinoside may all "inhibit" DNA synthesis, the actual effects of these agents differ. Retinoic acid appears to arrest cells in G1 without affecting the rate of DNA synthesis, while alpha-interferon and cytosine arabinoside "inhibit" DNA synthesis by reducing the rate of synthesis per se.