Agarose gel electrophoresis of DNA isolated from HL-60 leukemia cells and SK-N-MC NB cells after 24 hours of incubation with complete growth medium alone (control), actinomycin D (Act.D; 1 μg/mL), DFO (0.1 mmol/L and 2.5 mmol/L), or the PIH analogues (206, 308, 309, 311, and 315; 1 μmol/L and 10 μmol/L). The molecular weight marker was DNA molecular marker X from Boehringer Mannheim.