Induction to Granulocytic Differentiation of Human Promyelocytic Leukemia Cells （HL－6０） by Polyprenoic Acid （E5166）

The　effects of synthesized polyprenoic acid, E5166,on human promyelocytic　leukemia cell line, HL60, were examined. The cells continuously exposed to the drug in vitro underwent growth inhibition and granulocytic differentation. In the culture treated with E5166, the cell cycle progression was markedly inhibited and an accumukation of the cells in G1/0 phase was apparent on day 4 when a small number of granulocyte first appeared. Subsequently, the percentage of differentiated cellsin the culture increased continuously with the time of treatment and on day 7, 80％ of cells acquired the morphological characteristics of mature granulocytes. The close relationship between cell kinetics and differentiation was suggested, although the mechanisms by which E5166 induces differentiation and exerts its antiproliferative effect on HL-60 are unknown.

Differentitation

Leukemia

polyprenoic acid

Flow cytometry

BrdUrd

Cell cycle