Dietary phytoestrogen regulates estrogen receptor gene expression in human mammary carcinoma cells

Assessment of estrogenic potential from exudates of microcystin-producing and non-microcystin-producing Microcystis by metabolomics, machine learning and E-screen assay

Cyanobacterial blooms, often dominated by Microcystis aeruginosa, are capable of producing estrogenic effects. It is important to identify specific estrogenic compounds produced by cyanobacteria, though this can prove challenging owing to the complexity of exudate mixtures. In this study, we used untargeted metabolomics to compare components of exudates from microcystin-producing and non-microcystin-producing M. aeruginosa strains that differed with respect to their ability to produce microcystins, and across two growth phases. We identified 416 chemicals and found that the two strains produced similar components, mainly organoheterocyclic compounds (20.2%), organic acids and derivatives (17.3%), phenylpropanoids and polyketides (12.7%), benzenoids (12.0%), lipids and lipid-like molecules (11.5%), and organic oxygen compounds (10.1%). We then predicted estrogenic compounds from this group using random forest machine learning. Six compounds (daidzin, biochanin A, phenylethylamine, rhein, o-Cresol, and arbutin) belonging to phenylpropanoids and polyketides (3), benzenoids (2), and organic oxygen compound (1) were tested and exhibited estrogenic potency based upon the E-screen assay. This study confirmed that both Microcystis strains produce exudates that contain compounds with estrogenic properties, a growing concern in cyanobacteria management.

In utero and postnatal exposure to Foeniculum vulgare and Linum usitatissimum seed extracts: modifications of key enzymes involved in epigenetic regulation and estrogen receptors expression in the offspring's ovaries of NMRI mice

BACKGROUND

Early-life exposure to exogenous estrogens such as phytoestrogens (plant-derived estrogens) could affect later health through epigenetic modifications. Foeniculum vulgare (fennel) and Linum usitatissimum (flax) are two common medicinal plants with high phytoestrogen content. Considering the developmental epigenetic programming effect of phytoestrogens, the main goal of the present study was to evaluate the perinatal exposure with life-long exposure to hydroalcoholic extracts of both plants on offspring's ovarian epigenetic changes and estrogen receptors (ESRs) expression level as signaling cascades triggers of phytoestrogens.

METHODS

Pregnant mice were randomly divided into control (CTL) that received no treatment and extract-treated groups that received 500 mg/kg/day of fennel (FV) and flaxseed (FX) alone or in combination (FV + FX) during gestation and lactation. At weaning, female offspring exposed to extracts prenatally remained on the maternal-doses diets until puberty. Then, the ovaries were collected for morphometric studies and quantitative real-time PCR analysis.

RESULTS

A reduction in mRNA transcripts of the epigenetic modifying enzymes DNMTs and HDACs as well as estrogen receptors was observed in the FV and FX groups compared to the CTL group. Interestingly, an increase in ESRα/ESRβ ratio along with HDAC2 overexpression was observed in the FV + FX group.

CONCLUSION

Our findings clearly show a positive relationship between pre and postnatal exposure to fennel and flaxseed extracts, ovarian epigenetic changes, and estrogen receptors expression, which may affect the estrogen signaling pathway. However, due to the high phytoestrogen contents of these extracts, the use of these plants in humans requires more detailed investigations.

Biphasic effects of kaempferol on the estrogenicity in human breast cancer cells

Dietary flavonoids have attracted a great deal of attention as agents for preventing estrogen-related diseases, such as postmenopausal symptoms, and for reducing the risk of estrogen-dependent cancer. Kaempferol is one of the most commonly found dietary phytoestrogen. The aim of this study was to investigate the estrogenic and/or antiestrogenic effect of kaempferol, which can confirm its potency as a preventive agent against estrogen-related diseases. Kaempferol has both estrogenic and antiestrogenic activity, which are biphasic response on estrogen receptor. The estrogenic activity of kaempferol induced via ER-mediated pathway depending on E2 concentration (< or = 10(-12) M). Kaempferol (10(-5) M) also caused antiproliferative effect on MCF-7 cell in the presence of E2 (10(-11) M) and restored to the addition of excess E2 (10(-7) M), which confirms that antiproliferation of kaempferol was induced via ER-dependent pathway. However, at 10(-4) M, concentration higher than the concentrations at which the estrogenic effects of kaempferol are detected (10(-5) M), kaempferol induced strong antiproliferative effect, but were unaffected by the addition of excess E2 (10(-7) M) indicating that kaempferol exerts antiproliferation via ER-independent pathway. In particular, kaempferol blocked the focus formation induced by E2, which confirms that kaempferol might inhibit the malignant transformation caused by estrogens. Therefore, we suggested that kaempferol might regulate a suitable level of estrogenic activity in the body and is expected to have potential beneficial effects in preventing estrogen imbalance diseases (breast cancer, osteoporosis, cardiovascular disease and etc.).

Phytoestrogens

Collectively, plants contain several different families of natural products among which are compounds with weak estrogenic or antiestrogenic activity toward mammals. These compounds, termed phytoestrogens, include certain isoflavonoids, flavonoids, stilbenes, and lignans. The best-studied dietary phytoestrogens are the soy isoflavones and the flaxseed lignans. Their perceived health beneficial properties extend beyond hormone-dependent breast and prostate cancers and osteoporosis to include cognitive function, cardiovascular disease, immunity and inflammation, and reproduction and fertility. In the future, metabolic engineering of plants could generate novel and exquisitely controlled dietary sources with which to better assess the potential health beneficial effects of phytoestrogens.

Estrogen receptor is expressed in pig embryos during preimplantation development

Although estrogen is recognized as essential for embryonic development and maintenance of pregnancy, it remains unclear whether it has a direct role in the embryos themselves. The aim of this study was to investigate whether estrogen can have any effect in pig embryos during preimplantation development. Since the function of estrogen is mediated through its specific receptor, estrogen receptor (ER), the presence of ER mRNA and protein in pig embryos collected in vivo at different stages of preimplantation development was determined and compared. Using reverse transcription polymerase chain reaction, ER RNA was detected at the one-cell, two-cell, and four-cell stages. The level became undetectable at the five- to eight-cell stages and the morula stages and then reappeared again at the blastocyst stage. To determine whether the ER message observed in the embryos was translated into ER protein, immunocytochemical analysis was performed and the presence of ER protein was detected in oocytes at one-cell and four-cell stages. However, the amount of ER protein in porcine embryos at the blastocyst stage was still below the detection limit. The presence of ER mRNA at the blastocyst stages suggests that estrogen may start to act directly on pig embryos afterwards, and our results provide a basis for determining the direct role of estrogen in preimplantation pig embryos.