DIRECTED CELL-KILLING (APOPTOSIS) IN HUMAN LYMPHOBLASTOID-CELLS INCUBATED IN THE PRESENCE OF FARNESOL - EFFECT OF PHOSPHATIDYLCHOLINE

Previously reported observations have shown that trans-trans farnesol inhibits incorporation of choline into phosphatidylcholine and reduces the growth rate of the human acute leukemia CEM-C1 cell line (Melnyko vych, G., Haug, J.S. and Goldner, C.M. (1992) Biochem. Biophys. Res. C ommun. 186, 543-548). These findings have now been followed up in orde r to establish a relationship between the inhibition of phosphatidylch oline synthesis and the ensuing cell shrinkage and cell death which ta kes place at higher concentrations of farnesol or upon long incubation . The present results show that after incubation in the presence of fa rnesol the cells decrease in viability. Their nuclear DNA becomes frag mented at internucleosomal linker regions, showing characteristic patt ern of bands at 180 to 200 base-pair intervals. This farnesol-induced effect was also demonstrated by flow cytometry by staining the cellula r DNA with propidium iodide and was partially reversible with phosphat idylcholine.