Finally, PD exposure induced apoptosis of U 937 cells by caspase-3 dependent PARP and laminin A. It is therefore logical to assume that the main anti-leukemia activity of PD is to induce internal replication and mitosis, which is caused by the kinetics of compression of the spindle microtubules and the promotion of apoptosis of leukemia cells. Here, CASP3 is linked to leukemia.