[Cytokines modify 2-chlorodeoxyadenosine (2-CdA) toxicity in acute myeloid leukemia clonogenic cells (L-CFU)]

We investigated the effect of 2-chlorodeoxyadenosine (2-CdA) in concentrations: 10, 20, 50, 100, 150 and 300 nM/l on the clonal growth of acute myeloid leukemia clonogenic cells (L-CFU), after 24 h preincubation with recombinant granulocyte-macrophage colony stimulating factor (GM-CSF), interleukin-1 alpha (IL-1 alpha) or interleukin 3 (IL-3) and in conditioned medium obtained from phytohemagglutin stimulated lymphocytes (PHA-LCM). 2-CdA in concentration 300 nM/l significantly reduced (30%) the number of blast colonies in comparison with control experiments (p < 0.05). After preincubation of blast cells with cytokines (20% PHA-LCM, or GM-CSF--100 ng/ml, or IL-3--5 U/ml) an increase of 2-CdA cytotoxic effect on L-CFU clonal growth was observed. In experiments with 2-CdA (300 nM/l) and GM-CSF or PHA-LCM or IL-3 the number of blast colonies was reduced in 70%, 50% and 50%, respectively, (p < 0.05). Preincubation of blasts with IL-1, did not effect the 2-CdA--induced growth inhibition of CFU.