Phytoestrogens in Common Herbs Regulate Prostate Cancer Cell Growth in Vitro

Abstract

Prostate cancer is an important public health problem in the United States. Seven phytoestrogens found in common herbal products were screened for estrogen receptor binding and growth inhibition of androgen-insensitive (PC-3) and androgen-sensitive (LNCaP) human prostate tumor cells. In a competitive 3H-estradiol ligand binding assay using mouse uterine cytosol, 2.5 M quercetin, baicalein, genistein, epigallocatechin gallate (EGCG), and curcumin displaced > 85% of estradiol binding, whereas apigenin and resveratrol displaced > 40%. From growth inhibition studies in LNCaP cells, apigenin and curcumin were the most potent inhibitors of cell growth, and EGCG and baicalein were the least potent. In PC-3 cells, curcumin was the most potent inhibitor of cell growth, and EGCG was the least potent. In both cell lines, significant arrest of the cell cycle in S phase was induced by resveratrol and EGCG and in G2M phase by quercetin, baicalein, apigenin, genistein, and curcumin. Induction of apoptosis was induced by all of the 7 compounds in the 2 cell lines as shown by TUNEL and DNA fragmentation assays. Androgen responsiveness of the cell lines did not correlate with cellular response to the phytoestrogens. In conclusion, these 7 phytoestrogens, through different mechanisms, are effective inhibitors of prostate tumor cell growth.

The effects of curcumin on the invasiveness of prostate cancer in vitro and in vivo

“…2,3 Recently, curcumin has become a focus of interest with regard to its possible antitumor effects in prostate cancer. [12][13][14][15][16][17][18] This study shows for the first time, to our knowledge, that curcumin exerts an inhibitory effect on the invasiveness of DU-145 prostate cancer cells, and confirms this via both in vitro and in vivo testing.…”

“…This observation was previously reported in both androgen-dependent and androgen-independent prostate cancer cell lines. 12,14,16 Cytochrome c has been determined to function via the formation of a multicomplex, and subsequently initiates a cascade of caspase activations during chemically induced apoptosis. We identified the activation of cytochrome c, caspase-9, and poly ADP-ribose polymerase (PARP) after curcumin treatment via Western blotting (data not shown).…”

“…The results of previous studies have revealed that curcumin exerts pleiotropic effects on prostate cancer cells; however, its functions in invasion and metastasis have yet to be clearly elucidated. [12][13][14][15][16][17][18] Therefore, we assessed the effects of curcumin on the in vitro invasion of prostate cancer cells (DU-145), and further attempted to determine, using a tumor xenograft model, whether curcumin effected an inhibition of prostate cancer cell invasiveness.…”

Staying a Step Ahead of Cancer

“…Phytonutrients, often found in pungent and bitter vegetables, include resveratrol in grapes and curcumin in turmeric (Azari et al 2009, Feeney 2004, Greenlee, Hershman and Jacobson 2009, Holst and Williamson 2008, Kale, Gawande and Kotwal 2008, Kaur, Agarwal and Agarwal 2009, Lanzotti 2006, Mates et al 2011, Mattoo et al 2010, McGrath and Spigelman 2008, Neto 2007, Surh 2008, Wahlqvist and Lee 2007, Wenefrida et al 2009). Other molecules, including sulforaphane and genistein, an isoflavone found in soybeans, are currently being tested as pharmaceutical agents in cancer prevention (Ali et al 2005, Caetano et al 2006, Takahashi et al 2006, Shenouda et al 2004. A healthy balanced diet with these nutrients can help prevent cancer.…”

Soy isoflavone genistein in prevention and treatment of prostate cancer

“…Genistein inhibited the growth and induced apoptosis in LNCaP, DU-145 and PC3 prostatic cancer cells in a concentration p20 mM. [34][35][36][37][38][39][40][41][42] Genistein blocked the cell cycle progression at G 1 , inhibited PSA expression and modulated cell cycle gene regulation. 37,38,40,43 Expression of telomerase reverse transcriptase, c-myc mRNA and the MDM2 oncogene were downregulated by genistein, whereas p21 mRNA increased in response to genistein in PCa cells DU-145 and LNCaP.…”