Isoliquiritigenin inhibits the growth of prostate cancer

Objective: Isoliquiritigenin, one of the components in the root of Glycyrrhiza glabra L., is a member of the flavonoids, which are known to have an anti-tumor activity in vitro and in vivo. In this study, we investigated the antitumor effect of isoliquiritigenin on prostate cancer in vitro. Methods: DU145 and LNCaP prostate cancer cell lines were used as targets. We examined the effects of isoliquiritigenin on cell proliferation, cell cycle regulation and cell cycle-regulating gene expression. Further, we investigated the effects of isoliquiritigenin on the GADD153 mRNA and protein expression, and promoter activity. Results: Isoliquiritigenin significantly inhibited the proliferation of prostate cancer cell lines in a dose-dependent and time-dependent manner. Fluorescence-activated cell sorting (FAGS) analysis indicated that isoliquiritigenin induced S and G2/M phase arrest. Isoliquiritigenin enhanced the expression of GADD153 mRNA and protein associated with cell cycle arrest. Further, isoliquiritigenin stimulated transcriptional activity of GADD153 promoter dose-dependently. Conclusion: These findings suggest that isoliquiritigenin is a candidate agent for the treatment of prostate cancer and GADD153 may play an important role in isoliquiritigenin-induced cell cycle arrest and cell growth inhibition. (C) 2003 Elsevier Science B.V. All rights reserved.