Kinetic Response of Human Lymphoid Cells to Adriamycin-DNA Complex in Vitro

The lysosomotropic agent adriamycin-DNA complex was analyzed for its effect on cell cycle progression of human lymphoid cells in culture by means of pulse cytophotometry. Complexing to DNA slightly reduced the perturbation effects previously reported for adriamycin alone. The major kinetic response was a G₂block, the magnitude and duration of which was dependent on drug concentration and duration of treatment. When high drug concentrations were maintained for a prolonged period of time, an additional, completely reversible block in G, phase or at the G,-S boundary was observed, accounting for two-step G₂accumulation curves. Cell age markedly influenced the magnitude of G₂accumulation in that treatment of cells in S and early G₂phase was most effective.