Phytoestrogens induce differential estrogen receptor alpha- or Beta-mediated responses in transfected breast cancer cells.

Increased intake of phytoestrogens may be associated with a lower risk of cancer in the breast and several other sites, although there is controversy surrounding this activity. One of the mechanisms proposed to explain the activity of phytoestrogens is their ability to bind and activate human estrogen receptor alpha (ERalpha) and human estrogen receptor beta (ERbeta). Nine phytoestrogens were tested for their ability to transactivate ERalpha or ERbeta at a range of doses. Mammary adenocarcinoma (MCF-7) cells were co-transfected with either ERalpha or ERbeta, and an estrogen-response element was linked to a luciferase reporter gene. Dose-dependent responses were compared with the endogenous ligand 17beta-estradiol. Purified genistein, daidzein, apigenin, and coumestrol showed differential and robust transactivation of ERalpha- and ERbeta-induced transcription, with an up to 100-fold stronger activation of ERbeta. Equol, naringenin, and kaempferol were weaker agonists. When activity was evaluated against a background of 0.5 nM 17beta-estradiol, the addition of genistein, daidzein, and resveratrol superstimulated the system, while kaempferol and quercetin were antagonists at the highest doses. This transfection assay provides an excellent model to evaluate the activation of ERalpha and ERbeta by different phytoestrogens in a breast cancer context and can be used as a screening bioassay tool to evaluate the estrogenic activity of extracts of herbs and foods.

Tobacco or health.

Tobacco smoking is the major cause of premature death among men in the CCEE/NIS. Reliable information on smoking prevalence and tobacco use is scarce, but the overall evidence points to two different patterns: a traditional and a high prevalence pattern. The traditional pattern dominates in the NIS and some of the CCEE, and is characterized by a high smoking rate in men (about 50%) and a low rate in women (10%). Smoking by women, however, is increasing, starting with the younger age groups. The high prevalence pattern found in the Czech Republic, Hungary and Poland, for example, shows a high smoking prevalence in women (about 25%) in addition to a high prevalence in men. Predictions made in 1990 indicated further increases or stable tobacco consumption in the CCEE/NIS by the year 2000, in contrast with the steady decrease in western European countries. When smoking is combined with other types of harmful health behaviour and environmental influences, the result is some of the highest mortality rates from lung cancer and other diseases in the world. This situation has caused severe concern in public health professionals in many of the affected countries, but not in the public and policy-makers. The fundamental changes in social and economic structures have both improved and decreased opportunities to promote nonsmoking. In the short term, the negative influences seem to dominate, although some countries, such as Lithuania and Poland, are now introducing their first realistic policies on tobacco. In most countries, however, tobacco control has to compete with other issues for priority on a crowded public health agenda.(ABSTRACT TRUNCATED AT 250 WORDS)