Antiproliferative and apoptotic effects of β-elemene on human hepatoma HepG2 cells

β-elemene, a natural sesquiterpene extracted from the essential oils of Curcuma aromatica Salisb, has been shown to be effective against a wide range of tumors. In this study, the antitumor effect of β-elemene on a human hepatoma cell line, HepG2, and the mechanism involved have been investigated. MTT assay was used to determine the growth inhibition of hepatoma HepG2 cells in vitro. Apoptosis of HepG2 cells were demonstrated by fluorescence microscope with Hoechst 33258 staining and flow cytometry with Annexin V-FITC/PI double staining. Flow cytometry was performed to analyze the cell cycle distribution of HepG2 cells. The mRNA and protein expression of Fas and FasL were measured by RT-PCR and Western blot analysis. MTT results showed that β-elemene could inhibit the proliferation of HepG2 cells in a time- and dose- dependent manner. Our results showed β-elemene had positive effect on apoptosis through fluorescence microscope and flow cytometry assay. Furthermore, β-elemene could induce the cell cycle arrest of the HepG2 cells in the G2/M phase. Fas and FasL expression were obviously increased after β-elemene treatment in both mRNA and protein level. The present study indicates that β-elemene can effectively inhibit proliferation and induce apoptosis in hepatoma HepG2 cells, and the apoptosis induction is related with up-regulating of Fas/FasL expression.