Coactivity of apoptosis and G1 arrest by Chinese licorice root in the tumor suppressive effects of human breast cancer in vitro and in vivo

Abstract

5322

Licorice root is a botanical, a shrub native to southern Europe and Asia, which primarily has desirable qualities in sweetening and herbal medicine. European licorice root (Glycrrhiza glabra) is well-known to have the estrogenic and anti-proliferative properties in breast cancer cell. But, this study is first showed that Chinese licorice root (Glycyrrhiza uralensis) has the anti-tumor effect and estrogenicity. The extract of Chinese licorice root was fractionated in EtOH: H₂O (80: 20; 80% ethanol). In vitro cell growth was analyzed by the MTT assay, and this extract suppressed cell growth. Estrogenic activity was analyzed by the recombinant yeasts containing the human estrogen receptor (Saccharomyces cerevisiae ER + LYS 8127), and this extract exhibited estrogenicity like 17β- estradiol (E2, 10^-8M). This cell growth reduction was associated with apoptosis and G1 arrest in MCF-7 cells. Licorice root induced up-regulation of Bax and PARP cleavage, and also up-regulation of p53 and p21^waf1/cip1 and down-regulation of cdk 2 and cyclin E demonstrated by Western blotting. An in vivo MCF-7 xenograft model was used to study the effects of a licorice root-supplemented diet (1000mg/kg/day) on tumor growth in comparison with a control diet. The licorice root-supplemented diet significantly slowed MCF-7 tumor growth over 2 weeks. The results suggest that ethanol extract of licorice root might have the chemopreventive effect on human breast cancer cells and also useful for the alternatives of hormone replacement therapy without breast cancer risk. This study was supported by technology Development Program for Agriculture and Forestry, Ministry of Agriculture and Forestry (203004-03-HD110). arrest