Assessment of the cytotoxic effect of CGFYWLRSC-GG-D(KLAKLAK)2 peptide on leukemia cells in vitro. The effects of increasing doses of CGFYWLRSC + D(KLAKLAK)2 peptides or the CGFYWLRSC-GG-D(KLAKLAK)2 peptide are shown. Cell viability was measured via the DHL cell proliferation and viability assay (AnaSpec). The cell lines were (A) MOLT-4, (B) CCRF-CEM, (C) OCI-AML3, (D) HL-60, (E) K562, (F) RPMI-8226, (G) SR-786, and (H) U937. Results shown represent the average of 3 independent experiments.