phytoestrogens and 3-3--4-5--tetrahydroxystilbene

INTRODUATION: Resveratrol, a phytoestrogen present at a high concentration in red wine, has been reported to possess many health benefit effects that are protective against age-related diseases. Protein S (PS), an important anticoagulant factor in the protein C (PC) anticoagulant pathway, is mainly synthesized by hepatocytes, and its plasma level is decreased in high-estrogen conditions such as pregnancy and oral contraceptive use. The aim of this study was to investigate whether resveratrol affects PS expression in HepG2 cells.. The secreted and intracellular levels of PS were determined by an enzyme-linked ligandsorbent assay and Western blotting. The mRNA expressions of PS, PC and β chain of C4b-binding protein (C4BP-β) were analyzed by reverse transcription-polymerase chain reaction. The PS gene promotor activities in HepG2 cells transiently expressing estrogen receptor (ER) α were examined by a luciferase reporter assay.. Resveratrol dose- and time-dependently down-regulated the PS expression in HepG2 cells at a transcriptional level, resulting in a significant decrease in secreted PS; however, the PC and C4BP-β mRNA expressions were not affected. This action of resveratrol was not mediated through either the ER signaling or those of mitogen-activated protein kinases and protein kinase C. Piceatannol, a hydroxylated metabolite of resveratrol, and genistein, an isoflavone found in soy products, also down-regulated the PS expression.. Resveratrol down-regulates the PS expression in HepG2 cells in an ER-independent manner, and the two phenolic hydroxyls at carbon-3 and -5 of resveratrol may be involved in this function.

Topics: Blood Proteins; Blotting, Western; Carcinoma, Hepatocellular; Dose-Response Relationship, Drug; Down-Regulation; Enzyme-Linked Immunosorbent Assay; Estrogen Receptor alpha; Gene Expression Regulation, Neoplastic; Genistein; Hep G2 Cells; Histocompatibility Antigens; Humans; Liver Neoplasms; Molecular Structure; Phytoestrogens; Promoter Regions, Genetic; Protein C; Protein S; Resveratrol; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Stilbenes; Structure-Activity Relationship; Time Factors; Transcription, Genetic; Transfection; Wine

Previous epidemiological reports have suggested that red wine intake is associated with beneficial health effects due to the ability of certain phytochemical components to exert estrogen-like activity. It has been also documented that estrogens induce the proliferation of hormone-dependent breast cancer cells by binding to and transactivating estrogen receptor (ER) alpha, which in turn interacts with responsive DNA sequences located within the promoter region of target genes. In order to provide further insight into the positive association between wine consumption and the incidence of breast carcinoma in postmenopausal women, we have evaluated the estrogenic properties of two abundant wine-derived compounds, named piceatannol (PIC) and myricetin (MYR), using as model systems the hormone-sensitive MCF7 and the endocrine-independent SKBR3 breast cancer cells. On the basis of our experimental evidence PIC and MYR may contribute to the estrogenicity of red wine since: (1) they transactivate endogenous ER alpha; (2) they activate the agonist-dependent activation function (AF) 2 of ER alpha and ER beta in the context of the Gal4 chimeric proteins; (3) they rapidly induce the nuclear immunodetection of ER alpha; (4) they regulate the expression of diverse estrogen target genes; (5) they compete with 17beta-estradiol for binding to ER alpha and ER beta; and--as a biological counterpart of the aforementioned abilities--(6) they exert stimulatory effects on the proliferation of MCF7 cells. Hence, the estrogenic activity of PIC and MYR might be considered at least as a potential factor in the association of red wine intake and breast tumors, particularly in postmenopausal women.

Topics: Breast Neoplasms; Cell Line, Tumor; Cell Proliferation; Estradiol; Estrogen Receptor alpha; Estrogen Receptor beta; Female; Flavonoids; Gene Expression Regulation; Genes, Reporter; Humans; Molecular Structure; Phenols; Phytoestrogens; Protein-Tyrosine Kinases; Recombinant Fusion Proteins; Stilbenes; Wine