Leukemia cell death assay. Untreated OCI-AML3 cells served as a control to determine the background levels of cell death under the experimental conditions used. Cells were incubated with 20μM CGFYWLRSC + D(KLAKLAK)2 control peptide or with 20μM CGFYWLRSC-GG-D(KLAKLAK)2 for 20 hours at 37°C. annexin V–FITC/propidium iodide staining was used to detect the level of cell death via flow cytometry.