l-ase induces apoptosis in leukemic cells. OCI-AML3 cells and primary AML samples were cultured for 24 or 48 hours in 10% FBS MEM with or without 0.1, 1, or 10 UI/mL of E coli or E chrysanthemil-ase. Apoptosis was determined by Annexin V ^+/− 7AAD binding using flow cytometry (A-D) or by western blotting using an anti-caspase 3 antibody (E).