DIFFERENTIATION OF PROMYELOCYTIC LEUKEMIA-CELLS HL-60 INDUCED BY DAIDZEIN IN-VITRO AND IN-VIVO

We have screened more than one thousand synthetic and natural chemical s to explore differentiation inducers and found that daidzein has pote nt differentiation-inducing activity for human leukemia HL-60 cells, b oth in vitro and in vivo. In vitro study showed that daidzein at conce trations exceeding 10 mug/ml caused inhibition of HL-60 cells; and it induced differentiation of the cells into granulacytic lineage as judg ed by NBT reduction activity, phagocytic ability and morphological cha racteristics. Flow cytometry study indicated that daidzein arrested HL -60 cells in the G1 phase. The growth of HL-60 cells in the subrenal c apsules of mice and in diffusion chambers implanted into the periotone al cavities of mice was inhibited by 50 mg/kg daidzein. HL-60 cells tr eated with daidzein in vivo also exhibited characteristic morphologica l changes of matured cells. Moreover, the colony forming efficiency of HL-60 cells in diffusion chambers in mice was markedly inhibited by t he administration of daidzein.