We determined if soy isoflavones have dose-related estrogenic and methylation effects. Thirty-four healthy premenopausal women were randomized to 40 mg or 140 mg isoflavones daily through one ...menstrual cycle. Breast specific and systemic estrogenic effects were assessed measuring the estrogenic marker complement (C)3 and changes in cytology, whereas methylation assessment of 5 cancer related genes (p16, RASSF1A, RAR β 2, ER, and CCND2) was performed on intraductal specimens. Serum genistein significantly increased after consuming both isoflavone doses. Cytology did not significantly change at either isoflavone dose. Serum C3 levels posttreatment were inversely related to change in serum genistein (r =-0.76, P = 0.0045) in women consuming low but not high dose isoflavones. The RAR β 2 hypermethylation increase posttreatment correlated with the posttreatment genistein level considering the entire group (r = 0.67, P = 0.0017) and those receiving high-dose isoflavones (r = 0.68, P = 0.021). At the low but not the high isoflavone dose, CCND2 hypermethylation increase correlated with posttreatment genistein levels (r = 0.79, P = 0.011). In summary, the inverse correlation between C3 and genistein suggests an antiestrogenic effect. Isoflavones induced dose-specific changes in RAR β 2 and CCND2 gene methylation, which correlated with genistein levels. This work provides novel insights into estrogenic and methylation effects of dietary isoflavones.
Bisphenol A (BPA) is a monomer with estrogenic activity that is used in the production of food packaging, dental sealants, polycarbonate plastic, and many other products. The monomer has previously ...been reported to hydrolyze and leach from these products under high heat and alkaline conditions, and the amount of leaching increases as a function of use. We examined whether new and used polycarbonate animal cages passively release bioactive levels of BPA into water at room temperature and neutral pH. Purified water was incubated at room temperature in new polycarbonate and polysulfone cages and used (discolored) polycarbonate cages, as well as control (glass and used polypropylene) containers. The resulting water samples were characterized with gas chromatography/mass spectrometry (GC/MS) and tested for estrogenic activity using an MCF-7 human breast cancer cell proliferation assay. Significant estrogenic activity, identifiable as BPA by GC/MS (up to 310 μg/L), was released from used polycarbonate animal cages. Detectable levels of BPA were released from new polycarbonate cages (up to 0.3 μg/L) as well as new polysulfone cages (1.5 μg/L), whereas no BPA was detected in water incubated in glass and used polypropylene cages. Finally, BPA exposure as a result of being housed in used polycarbonate cages produced a 16% increase in uterine weight in prepubertal female mice relative to females housed in used polypropylene cages, although the difference was not statistically significant. Our findings suggest that laboratory animals maintained in polycarbonate and polysulfone cages are exposed to BPA via leaching, with exposure reaching the highest levels in old cages.
Background: Hormonal alterations during development have lifelong effects on the prostate gland. Endogenous estrogens, including 17β-estradiol (E₂), and synthetic estrogenic endocrine disruptors, ...such as bisphenol A (BPA), have similar effects on prostate development. Increasing exposure to estrogens within the low-dose, physiologic range results in permanent increases in the size and androgen responsiveness of the prostate, whereas exposure within the high-dose, pharmacologic range has the opposite effects. Objectives: We tested the hypothesis that the low-dose effects of estrogens on the developing prostate are associated with increased expression of androgen receptor (Ar) and estrogen receptor 1 (α) (Esr1) genes in mesenchyme cells. Methods: Ar and Esrl mRNA levels were quantified in primary cultures of fetal mouse prostate mesenchyme cells treated with E₂ and BPA. Discusion: Ar and Esrl mRNA expression increased in response to E₂, with thresholds of 0.001 and 0.037 nM, respectively; and in response to BPA, with a threshold of 1 nM for both mRNAs. We did not observe the expected inhibition of Ar mRNA expression by pharmacologic levels of E₂ relative to unexposed cells. Conclusion: The observed induction of gene expression occurred at concentrations within the range of free E₂ previously shown to permanently increase prostate size, thus supporting the involvement of direct effects of estrogens on gene expression in prostate mesenchyme. The effects of BPA occurred within the range of concentrations currently measured in human serum, demonstrating the vulnerability of developing tissues to xenoestrogens.
First full term pregnancy (FFTP) completed at a young age has been linked to low long term breast cancer risk, whereas late FFTP pregnancy age confers high long term risk, compared to nulliparity. ...Our hypothesis was that proteins linked to breast cancer would be differentially expressed in human milk collected at three time points during lactation based on age at FFTP.
We analyzed breast milk from 72 lactating women. Samples were collected within 10 days of the onset of lactation (baseline-BL), two months after lactation started and during breast weaning (W). We measured 16 proteins (11 kallikreins (KLKs), basic fibroblast growth factor, YKL-40, neutrophil gelatinase-associated lipocalin and transforming growth factor (TGF) β-1 and -2) associated with breast cancer, most known to be secreted into milk.
During lactation there was a significant change in the expression of 14 proteins in women < 26 years old and 9 proteins in women > = 26 at FFTP. The most significant (p < .001) changes from BL to W in women divided by FFTP age (< 26 vs. > = 26) were in KLK3,6, 8, and TGFβ2 in women < 26; and KLK6, 8, and TGFβ2 in women > = 26. There was a significant increase (p = .022) in KLK8 expression from BL to W depending on FFTP age. Examination of DNA methylation in the promoter region of KLK6 revealed high levels of methylation that did not explain the observed changes in protein levels. On the other hand, KLK6 and TGFβ1 expression were significantly associated (r2 = .43, p = .0050).
The expression profile of milk proteins linked to breast cancer is influenced by age at FFTP. These proteins may play a role in future cancer risk.
Background: Although estrogenic chemicals can disrupt development of the reproductive system, there is debate about whether phytoestrogens in soy are beneficial, benign, or harmful. Objectives: We ...compared reproductive and metabolic characteristics in male and female mice reared and maintained on non-soy low-phytoestrogen feed or soy-based high-phytoestrogen feed. Methods: The low-phytoestrogen diet was non-soy PMI 5K96 (verified casein diet), and the high-phytoestrogen diet consisted of soy-based PMI 5008 during pregnancy and lactation and soy-based PMI 5001 maintenance feed after weaning. Results: In fetuses whose mothers consumed the low-phytoestrogen PMI 5K96 feed, we found a paradoxical significant elevation in endogenous serum estradiol, which was associated postnatally with adverse reproductive outcomes referred to as the "fetal estrogenization syndrome (FES)". In females, this syndrome included early puberty and increased uterine responsiveness to estrogen, and in males, it included reduced testis, epididymis, and seminal vesicle size, but an enlarged prostate. The low-phytoestrogen-fed males and females were lighter at birth, but, between weaning and adulthood, they became obese and developed abnormally high serum leptin levels; these males, but not females, showed impaired glucose regulation. Conclusions: Removing phytoestrogens from mouse feed produces an obese phenotype consistent with metabolic syndrome, and the associated reproductive system abnormalities are consistent with FES due to elevated endogenous fetal estradiol. Laboratory rodents may have become adapted to high-phytoestrogen intake over many generations of being fed soy-based commercial feed; removing all phytoestrogens from feed leads to alterations that could disrupt many types of biomedical research.
► Prostate development is dependent on androgen action but is modulated by estrogens. ► Early life estrogen exposure can permanently impact adult prostate size and function ► Different effects of ...estrogen are seen at low and high doses. ► Early exposure to BPA and other xenoestrogens affects adult prostate morphology, androgen receptors and disease ► Prostate differentiation is directed by interaction of AR- and ER- driven events.
Development and differentiation of the prostate from the fetal urogenital sinus (UGS) is dependent on androgen action via androgen receptors (AR) in the UGS mesenchyme. Estrogens are not required for prostate differentiation but do act to modulate androgen action. In mice exposure to exogenous estrogen during development results in permanent effects on adult prostate size and function, which is mediated through mesenchymal estrogen receptor (ER) alpha. For many years estrogens were thought to inhibit prostate growth because estrogenic drugs studied were administered at very high concentrations that interfered with normal prostate development. There is now extensive evidence that exposure to estrogen at very low concentrations during the early stages of prostate differentiation can stimulate fetal/neonatal prostate growth and lead to prostate disease in adulthood. Bisphenol A (BPA) is an environmental endocrine disrupting chemical that binds to both ER receptor subtypes as well as to AR. Interest in BPA has increased because of its prevalence in the environment and its detection in over 90% of people in the USA. In tissue culture of fetal mouse UGS mesenchymal cells, BPA and estradiol stimulated changes in the expression of several genes. We discuss here the potential involvement of estrogen in regulating signaling pathways affecting cellular functions relevant to steroid hormone signaling and metabolism and to inter- and intra-cellular communications that promote cell growth. The findings presented here provide additional evidence that BPA and the estrogenic drug ethinylestradiol disrupt prostate development in male mice at administered doses relevant to human exposures.
What Happens to the Whistleblowers? Ruhlen, Rachel L.
Science (American Association for the Advancement of Science),
10/2006, Letnik:
314, Številka:
5797
Journal Article
The ACI rat is a unique model of human breast cancer in that mammary cancers are induced by estrogen without carcinogens, irradiation, xenografts or transgenic manipulations. We sought to ...characterize mammary cancers in a congenic variant of the ACI rat, the ACI.COP-Ept2. All rats with estradiol implants developed mammary cancers in 5-7 months. Rats bearing estradiol-induced mammary cancers were treated with tamoxifen for three weeks. Tamoxifen reduced tumor mass, measured by magnetic resonance imaging, by 89%. Tumors expressed estrogen receptors (ER), progesterone receptor (PR), and Erbb2. ERα and PR were overexpressed in tumor compared to adjacent non-tumor mammary gland. Thus, this model is highly relevant to hormone responsive human breast cancers.
Women's Health Initiative findings indicate that hormone replacement therapy may increase breast cancer and cardiovascular disease risk. Black cohosh extract (BCE) is a popular alternative that ...reduced menopausal symptoms in several clinical trials. Preclinical studies have addressed the estrogenic properties of BCE, with conflicting results. The estrogenic influence of BCE on the breast has not been investigated. Black cohosh is standardized to triterpenes, but the activity and mechanism of action of these compounds are unknown. The study goals were to determine 1) triterpene content of 2 commercially available BCE preparations and 2) the effect of BCE on circulating and breast-specific estrogenic markers. Two black cohosh preparations were analyzed for triterpene content. Postmenopausal women took BCE for 12 wk followed by a 12-wk washout. One BCE preparation contained trace amounts and another contained 2.5% triterpenes. Women taking BCE with 2.5% triterpenes experienced relief of menopausal symptoms, with reversion toward baseline after washout. BCE had no effect on estrogenic markers in serum and no effect on pS2 or cellular morphology in nipple aspirate fluid. Triterpene content in commercially available black cohosh preparations varies. BCE standardized to 2.5% triterpenes relieved menopausal symptoms without systemic or breast-specific estrogenic effects.
Mobilization of a joint affects local tissue directly but may also have other effects that are mediated through the central nervous system.
To identify differential gene expression in the spinal ...cords of rats with or without inflammatory joint injury after manual therapy or no treatment.
Rats were randomly assigned to 1 of 4 treatment groups: no injury and no touch (NI/NT), injury and no touch (I/NT), no injury and manual therapy (NI/MT), and injury and manual therapy (I/MT). We induced acute inflammatory joint injury in the rats by injecting carrageenan into an ankle. Rats in the no-injury groups did not receive carrageenan injection. One day after injury, rats received manual therapy to the knee of the injured limb. Rats in the no-touch groups were anesthetized without receiving manual therapy. Spinal cords were harvested 30 minutes after therapy or no touch, and spinal cord gene expression was analyzed by microarray for 3 comparisons: NI/NT vs I/NT, I/MT vs I/NT, and NI/NT vs NI/MT.
Three rats were assigned to each group. Of 38,875 expressed sequence tags, 755 were differentially expressed in the NI/NT vs I/NT comparison. For the other comparisons, no expressed sequence tags were differentially expressed. Cluster analysis revealed that the differentially expressed sequence tags were over-represented in several categories, including ion homeostasis (enrichment score, 2.29), transmembrane (enrichment score, 1.55), and disulfide bond (enrichment score, 2.04).
An inflammatory injury to the ankle of rats caused differential expression of genes in the spinal cord. Consistent with other studies, genes involved in ion transport were among those affected. However, manual therapy to the knees of injured limbs or to rats without injury did not alter gene expression in the spinal cord. Thus, evidence for central nervous system mediation of manual therapy was not observed.
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