A Vitex agnus-castus Extract Inhibits Cell Growth and Induces Apoptosis in Prostate Epithelial Cell Lines

Abstract

Extracts of Vitex agnus-castus fruits (VACF) are described to have beneficial effects on disorders related to hyperprolactinemia (cycle disorders, premenstrual syndrome). A VACF extract has recently been shown to exhibit antitumor activities in different human cancer cell lines. In the present study, we explored the antiproliferative effects of a VACF extract with a particular focus on apoptosis-inducing and potential cytotoxic effects. Three different human prostate epithelial cell lines (BPH-1, LNCaP, PC-3) representing different disease stages and androgen responsiveness were chosen. The action of VACF on cell viability was assessed using the WST-8-tetrazolium assay. Cell proliferation in cells receiving VACF alone or in combination with a pan-caspase inhibitor (Z-VAD-fmk) was quantified using a Crystal Violet assay. Flow cytometric cell cycle analysis and measurement of DNA fragmentation using an ELISA method were used for studying the induction of apoptosis. Lactate dehydrogenase (LDH) activity was determined as a marker of cytotoxicity. The extract inhibited proliferation of all three cell lines in a concentration-dependent manner with IC₅₀ values below 10 μg/mL after treatment for 48 h. Cell cycle analysis and DNA fragmentation assays suggest that part of the cells were undergoing apoptosis. The VACF-induced decrease in cell number was partially inhibited by Z-VAD-fmk, indicating a caspase-dependent apoptotic cell death. However, the concentration-dependent LDH activity of VACF treated cells indicated cytotoxic effects as well. These data suggest that VACF contains components that inhibit proliferation and induce apoptosis in human prostate epithelial cell lines. The extract may be useful for the prevention and/or treatment not only of benign prostatic hyperplasia but also of human prostate cancer.

Abbreviations

BPH:benign prostatic hyperplasia

CV:Crystal Violet

DMSO:dimethyl sulfoxide

ER:estrogen receptor

FBS:fetal bovine serum

LDH:lactate dehydrogenase

O.D.:optical density

PRL:prolactin

PCA:prostate cancer

VACF:Vitex agnus-castus fruit extract

Vitex agnus-castus - prostate - cell lines - apoptosis - cell cycle caspase

References

• 1 Wuttke W, Jarry H, Christoffel V, Spengler B, Seidlova-Wuttke D. Chaste tree (Vitex agnus-castus) - pharmacology and clinical indications.  Phytomedicine. 2003;  10 348-57
• 2 Jarry H, Spengler B, Porzel A, Schmidt J, Wuttke W, Christoffel V. Evidence for estrogen receptor beta-selective activity of Vitex agnus-castus and isolated flavones.  Planta Med. 2003;  69 945-7
• 3 Dixon-Shanies D, Shaikh N. Growth inhibition of human breast cancer cells by herbs and phytoestrogens.  Oncol Rep. 1999;  6 1383-7
• 4 Ohyama K, Akaike T, Hirobe C, Yamakawa T. Cytotoxicity and apoptotic inducibility of Vitex agnus-castus fruit extract in cultured human normal and cancer cells and effect on growth.  Biol Pharm Bull. 2003;  26 10-8
• 5 Hayward S W, Dahiya R, Cunha G R, Bartek J, Deshpande N, Narayan P. Establishment and characterization of an immortalized but non-transformed human prostate epithelial cell line: BPH-1.  In Vitro Cell Dev Biol Anim. 1995;  31 14-24
• 6 Horoszewicz J S, Leong S S, Chu T M, Wajsman Z L, Friedman M, Papsidero L, Kim U, Chai L S, Kakati S, Arya S K, Sandberg A A. The LNCaP cell line - a new model for studies on human prostatic carcinoma.  Prog Clin Biol Res. 1980;  37 115-32
• 7 Kaighn M E, Narayan K S, Ohnuki Y, Lechner J F, Jones L W. Establishment and characterization of a human prostatic carcinoma cell line (PC-3).  Invest Urol. 1979;  17 16-23
• 8 Kueng W, Silber E, Eppenberger U. Quantification of cells cultured on 96-well plates.  Anal Biochem. 1989;  182 6-9
• 9 Darzynkiewicz Z, Bedner E, Smolewski P. Flow cytometry in analysis of cell cycle and apoptosis.  Semin Hematol. 2001;  38 179-93
• 10 Jensen O M, Esteve J, Moller H, Renard H. Cancer in the European Community and its member states.  Eur J Cancer. 1990;  26 1167-256
• 11 Griffiths K, Morton M S, Denis L. Certain aspects of molecular endocrinology that relate to the influence of dietary factors on the pathogenesis of prostate cancer.  Eur Urol. 1999;  35 443-55