Induction of the apoptosis of HL-60 promyelocytic leukemia cells by Eurya emarginata

This study examined the inhibitory effect of Eurya emarginata extracts on the growth of cancer cells. The ethylacetate (EtOAc) fraction of the E. emarginata leaves markedly inhibited the growth of leukemia cells including HL-60. When the HL-60 cells were treated with its EtOAc fraction, DNA fragmentation and sub-G1 hypodiploid cells were observed. Moreover, the EtOAc fraction of E. emarginata reduced the c-Myc and Bcl-2 protein and mRNA levels in a time-dependent manner, whereas the Bax protein and mRNA expression levels were slightly increased. The results suggest that the inhibitory effect of E. emarginata on the growth of HL-60 appears to arise from the induction of apoptosis via the down-regulation of Bcl-2 and c-Myc expression with an increase in the Bax expression level. (C) 2003 Elsevier Ireland Ltd. All rights reserved.