Objective      To determine the effect of emodin on the proliferation and apoptosis in human acute myeloid leukemia cell line KG-1a

and to investigate the role of Bcl-2/Bax in the process.       Methods       KG-1a cells were exposed to emodin at the doses of 25

50

100 and 200  mol/L. Cell viability was measured with MTT assay. The change of cell cycle and apoptosis were detected by flow cytometry (FCM). The expression of Bcl-2/Bax mRNA was assessed by RT-PCR.       Results        Emodin significantly inhibited the proliferation in KG-1a cells

with IC

50

value of 171.8 μmol/L after treatment for 48 h. Emodin blocked cell cycle at G

0

/G

1

phase

and

a remarkable sub-G1 apoptotic peak was observed according to the detection of flow cytometry.  The expression of Bcl-2 was down-regulated

while that of Bax was obviously up-regulated in a dose-dependent manner.       Conclusion        Emodin can significantly induce apoptosis of KG-1a cells

which might be related to the down-regulation of Bcl-2 and up-regulation of Bax.