[Apoptosis of human hepatoma HepG2 cells induced by emodin in vitro]

Emodin (3-methyl-1,6,8-trihydro- xyanthrax-quinone) is the main effective composition of some Chinese herbs. Previous studies showed that emodin could inhibit the proliferation of some kind of tumor cells, such as breast cancer and lung cancer, while the mechanism(s) by which emodin suppresses tumor growth remains unknown. The study was designed to investigate the inhibitory effects and mechanisms of emodin-induced cell death in human hepatoma cell HepG2.

MTT assay was used to evaluate the IC(50) of emodin on HepG2 cells. Through soft agar assay, the ability of cell proliferation when exposed to emodin at various dosages was detected. DNA fragmentation (ladder) and flow cytometry analysis were applied to investigate the effects and mechanisms of emodin on HepG2 cells.

Emodin could inhibit the growth of HepG2 cells significantly with IC(50) of 36+/-2.6 microg/ml; and could inhibit the colony formation of the cells in soft agar. After treatment of emodin,extraction of cancer cells exhibited typical DNA fragmentation, and flow cytometry analysis showed apoptosis in a dosage- dependent manner. As the concentration of emodin raised from 10 microg/ml to 20 microg/ml,the ratio of apoptotic cells increased from 27.3% to 59.6%. Under the concentration of 40 microg/ml, there were almost no living cells detected.

Emodin may inhibit the growth and proliferation of HepG2 cells through the way of apoptosis introduction.