Xanthohumol, a prenylflavonoid derived from hops induces apoptosis and inhibits NF-kappaB activation in prostate epithelial cells

There is increasing evidence that certain natural compounds found in plants may be useful as cancer chemopreventive or chemotherapeutic agents. Limited in vitro studies indicate that several prenylated flavonoids present in the hop plant (Humulus lupulus) possess anticarcinogenic properties. The purpose of this study was to investigate the anti-tumorigenic effects of xanthohumol (XN), the major prenylflavonoid in hops, on prostate cancer and benign prostate hyperplasia. BPH-1 and PC3 cell lines were used in our study to represent both non-tumorigenic hyperplasia and malignant prostate cancer. In both BPH-1 and PC3 cells, XN and its oxidation product, XAL, decreased cell viability in a dose dependent manner (2.5-20 mu M) as determined by MTT assay and caused an increase in the formation of early and late apoptotic cells as determined by Annexin V staining and multicaspase assays. XN and its oxygenated derivative also induced cell cycle changes in both cells lines, seen in an elevated sub G1 peak at 48 h treatment. Western blot analysis was performed to confirm the activation of proapoptotic proteins, Bax and p53. XN and its derivative caused decreased activation of NF kappa B. This work suggests that XN and its oxidation product, XAL, may be potentially useful as a chernopreventive agent during prostate hyperplasia and prostate carcinogenesis, acting via induction of apoptosis and down-regulation of NF kappa B activation in BPH-1 cells. (c) 2006 Elsevier Ireland Ltd. All rights reserved.