ANXA5 and leukemia: To confirm the ability of compounds 3, 5 and 6 to induce apoptosis in leukemia cells, we tested phosphatidylserine (PS) distribution in K562 and MOLT-4 cells using fluorescently labelled annexin V. In the non-apoptotic cells, PS is present only in the inner (cytoplasmic) leaflet of the cell membrane.