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Catanese MC, Vandenberg LN. Bisphenol S (BPS) Alters Maternal Behavior and Brain in Mice Exposed During Pregnancy/Lactation and Their Daughters. Endocrinology 2017; 158:516-530. [PMID: 28005399 PMCID: PMC5460783 DOI: 10.1210/en.2016-1723] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/02/2016] [Accepted: 12/05/2016] [Indexed: 01/12/2023]
Abstract
Estrogenic endocrine disrupting chemicals have been shown to disrupt maternal behavior in rodents. We investigated the effects of an emerging xenoestrogen, bisphenol S (BPS), on maternal behavior and brain in CD-1 mice exposed during pregnancy and lactation (F0 generation) and in female offspring exposed during gestation and perinatal development (F1 generation). We observed different effects in F0 and F1 dams for a number of components of maternal behavior, including time on the nest, time spent on nest building, latency to retrieve pups, and latency to retrieve the entire litter. We also characterized expression of estrogen receptor α in the medial preoptic area (MPOA) and quantified tyrosine hydroxylase immunoreactive cells in the ventral tegmental area, 2 brain regions critical for maternal care. BPS-treated females in the F0 generation had a statistically significant increase in estrogen receptor α expression in the caudal subregion of the central MPOA in a dose-dependent manner. In contrast, there were no statistically significant effects of BPS on the MPOA in F1 dams or the ventral tegmental area in either generation. This work demonstrates that BPS affects maternal behavior and brain with outcomes depending on generation, dose, and postpartum period. Many studies examining effects of endocrine disrupting chemicals view the mother as a means by which offspring can be exposed during critical periods of development. Here, we demonstrate that pregnancy and lactation are vulnerable periods for the mother. We also show that developmental BPS exposure alters maternal behavior later in adulthood. Both findings have potential public health implications.
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Affiliation(s)
- Mary C. Catanese
- Graduate Program in Neuroscience and Behavior, University of Massachusetts–Amherst, Amherst, Massachusetts 01003; and
| | - Laura N. Vandenberg
- Graduate Program in Neuroscience and Behavior, University of Massachusetts–Amherst, Amherst, Massachusetts 01003; and
- Department of Environmental Health Sciences, School of Public Health and Health Sciences, University of Massachusetts–Amherst, Amherst, Massachusetts 01003
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Paulose T, Speroni L, Sonnenschein C, Soto AM. Estrogens in the wrong place at the wrong time: Fetal BPA exposure and mammary cancer. Reprod Toxicol 2014; 54:58-65. [PMID: 25277313 DOI: 10.1016/j.reprotox.2014.09.012] [Citation(s) in RCA: 73] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2014] [Revised: 08/19/2014] [Accepted: 09/09/2014] [Indexed: 01/27/2023]
Abstract
Iatrogenic gestational exposure to diethylstilbestrol (DES) induced alterations of the genital tract and predisposed individuals to develop clear cell carcinoma of the vagina as well as breast cancer later in life. Gestational exposure of rodents to a related compound, the xenoestrogen bisphenol-A (BPA) increases the propensity to develop mammary cancer during adulthood, long after cessation of exposure. Exposure to BPA during gestation induces morphological alterations in both the stroma and the epithelium of the fetal mammary gland at 18 days of age. We postulate that the primary target of BPA is the fetal stroma, the only mammary tissue expressing estrogen receptors during fetal life. BPA would then alter the reciprocal stroma-epithelial interactions that mediate mammogenesis. In addition to this direct effect on the mammary gland, BPA is postulated to affect the hypothalamus and thus in turn affect the regulation of mammotropic hormones at puberty and beyond.
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MESH Headings
- Age Factors
- Animals
- Benzhydryl Compounds/toxicity
- Breast Neoplasms/chemically induced
- Breast Neoplasms/metabolism
- Breast Neoplasms/pathology
- Cell Communication/drug effects
- Cell Transformation, Neoplastic/chemically induced
- Cell Transformation, Neoplastic/metabolism
- Cell Transformation, Neoplastic/pathology
- Dose-Response Relationship, Drug
- Endocrine Disruptors/toxicity
- Epithelial Cells/drug effects
- Epithelial Cells/metabolism
- Epithelial Cells/pathology
- Estrogens/toxicity
- Female
- Gestational Age
- Humans
- Hypothalamus/drug effects
- Hypothalamus/metabolism
- Mammary Glands, Animal/drug effects
- Mammary Glands, Animal/growth & development
- Mammary Glands, Animal/metabolism
- Mammary Glands, Animal/pathology
- Mammary Glands, Human/drug effects
- Mammary Glands, Human/growth & development
- Mammary Glands, Human/metabolism
- Mammary Glands, Human/pathology
- Maternal Exposure/adverse effects
- Phenols/toxicity
- Pregnancy
- Prenatal Exposure Delayed Effects
- Risk Assessment
- Risk Factors
- Stromal Cells/drug effects
- Stromal Cells/metabolism
- Stromal Cells/pathology
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Affiliation(s)
- Tessie Paulose
- Department of Integrative Physiology and Pathobiology, Tufts University School of Medicine, 136 Harrison Avenue, Boston, MA 02111, United States.
| | - Lucia Speroni
- Department of Integrative Physiology and Pathobiology, Tufts University School of Medicine, 136 Harrison Avenue, Boston, MA 02111, United States.
| | - Carlos Sonnenschein
- Department of Integrative Physiology and Pathobiology, Tufts University School of Medicine, 136 Harrison Avenue, Boston, MA 02111, United States.
| | - Ana M Soto
- Department of Integrative Physiology and Pathobiology, Tufts University School of Medicine, 136 Harrison Avenue, Boston, MA 02111, United States.
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Yoon K, Kwack SJ, Kim HS, Lee BM. Estrogenic endocrine-disrupting chemicals: molecular mechanisms of actions on putative human diseases. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART B, CRITICAL REVIEWS 2014; 17:127-74. [PMID: 24749480 DOI: 10.1080/10937404.2014.882194] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Endocrine-disrupting chemicals (EDC), including phthalates, bisphenol A (BPA), phytoestrogens such as genistein and daidzein, dichlorodiphenyltrichloroethane (DDT), and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), are associated with a variety of adverse health effects in organisms or progeny by altering the endocrine system. Environmental estrogens, including BPA, phthalates, and phytoestrogens, are the most extensively studied and are considered to mimic the actions of endogenous estrogen, 17β-estradiol (E2). Diverse modes of action of estrogen and estrogen receptors (ERα and ERβ) have been described, but the mode of action of estrogenic EDC is postulated to be more complex and needs to be more clearly elucidated. This review examines the adverse effects of estrogenic EDC on male or female reproductive systems and molecular mechanisms underlying EDC effects that modulate ER-mediated signaling. Mechanisms of action for estrogenic EDC may involve both ER-dependent and ER-independent pathways. Recent findings from systems toxicology of examining estrogenic EDC are also discussed.
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Affiliation(s)
- Kyungsil Yoon
- a Lung Cancer Branch , Research Institute, National Cancer Center , Goyang , Gyeonggi-do , South Korea
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Alonso-Magdalena P, Ropero AB, Soriano S, García-Arévalo M, Ripoll C, Fuentes E, Quesada I, Nadal Á. Bisphenol-A acts as a potent estrogen via non-classical estrogen triggered pathways. Mol Cell Endocrinol 2012; 355:201-7. [PMID: 22227557 DOI: 10.1016/j.mce.2011.12.012] [Citation(s) in RCA: 236] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/22/2011] [Revised: 12/02/2011] [Accepted: 12/14/2011] [Indexed: 01/03/2023]
Abstract
Bisphenol-A (BPA) is an estrogenic monomer commonly used in the manufacture of numerous consumer products such as food and beverage containers. Widespread human exposure to significant doses of this compound has been reported. Traditionally, BPA has been considered a weak estrogen, based on its lower binding affinity to the nuclear estrogen receptors (ERs) compared to 17-β estradiol (E2) as well as its low transcriptional activity after ERs activation. However, in vivo animal studies have demonstrated that it can interfere with endocrine signaling pathways at low doses during fetal, neonatal or perinatal periods as well as in adulthood. In addition, mounting evidence suggests a variety of pathways through which BPA can elicit cellular responses at very low concentrations with the same or even higher efficiency than E2. Thus, the purpose of the present review is to analyze with substantiated scientific evidence the strong estrogenic activity of BPA when it acts through alternative mechanisms of action at least in certain cell types.
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Affiliation(s)
- Paloma Alonso-Magdalena
- Instituto de Bioingeniería and CIBERDEM, Universidad Miguel Hernández de Elche, 03202 Elche, Spain.
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Watson CS, Jeng YJ, Hu G, Wozniak A, Bulayeva N, Guptarak J. Estrogen- and xenoestrogen-induced ERK signaling in pituitary tumor cells involves estrogen receptor-α interactions with G protein-αi and caveolin I. Steroids 2012; 77:424-32. [PMID: 22230296 PMCID: PMC3304022 DOI: 10.1016/j.steroids.2011.12.025] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/27/2011] [Revised: 12/21/2011] [Accepted: 12/22/2011] [Indexed: 12/16/2022]
Abstract
UNLABELLED Multiple physiologic estrogens (estradiol, estriol, and estrone), as well as xenoestrogenic compounds (including alkylphenols and bisphenol A), can act via nongenomic signaling initiated by liganding of the plasma membrane estrogen receptor-α (mERα). We examined heterotrimeric G protein involvement leading to extracellular-regulated kinase (ERK) activation in GH3/B6/F10 rat anterior pituitary tumor cells that express abundant mERα, and smaller amounts of mERβ and GPR30. A combination of microarrays, immunoblots, and quantitative immunoassays demonstrated the expression of members of all α, β, and γ G protein classes in these cells. Use of selective inhibitors showed that the G(αi) subtype was the primary initiator of downstream ERK signaling. Using antibodies against the GTP-bound form of G(α) protein subtypes i and s, we showed that xenoestrogens (bisphenol A, nonylphenol) activated G(αi) at 15-30s; all alkylphenols examined subsequently suppressed activation by 5min. GTP-activation of G(αi) for all estrogens was enhanced by irreversible cumulative binding to GTPγS. In contrast, G(αs) was neither activated nor deactivated by these treatments with estrogens. ERα and G(αi) co-localized outside nuclei and could be immuno-captured together. Interactions of ERα with G(αi) and caveolin I were demonstrated by epitope proximity ligation assays. An ERα/β antagonist (ICI182780) and a selective disruptor of caveolar structures (nystatin) blocked estrogen-induced ERK activation. CONCLUSIONS Xenoestrogens, like physiologic estrogens, can evoke downstream kinase signaling involving selective interactions of ERα with G(αi) and caveolin I, but with some different characteristics, which could explain their disruptive actions.
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Affiliation(s)
- Cheryl S Watson
- Dept. of Biochemistry & Molecular Biology, Univ. of Texas Medical Branch, Galveston, TX 77555-0645, USA.
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Watson CS, Alyea RA, Cunningham KA, Jeng YJ. Estrogens of multiple classes and their role in mental health disease mechanisms. Int J Womens Health 2010; 2:153-66. [PMID: 21072308 PMCID: PMC2971739 DOI: 10.2147/ijwh.s6907] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2010] [Indexed: 12/21/2022] Open
Abstract
Gender and sex hormones can influence a variety of mental health states, including mood, cognitive development and function, and vulnerability to neurodegenerative diseases and brain damage. Functions of neuronal cells may be altered by estrogens depending upon the availability of different physiological estrogenic ligands; these ligands and their effects vary with life stages, the genetic or postgenetic regulation of receptor levels in specific tissues, or the intercession of competing nonphysiological ligands (either intentional or unintentional, beneficial to health or not). Here we review evidence for how different estrogens (physiological and environmental/dietary), acting via different estrogen receptor subtypes residing in alternative subcellular locations, influence brain functions and behavior. We also discuss the families of receptors and transporters for monoamine neurotransmitters and how they may interact with the estrogenic signaling pathways.
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Membrane-impermeable estrogen is involved in regulation of calbindin-D9k expression via non-genomic pathways in a rat pituitary cell line, GH3 cells. Toxicol In Vitro 2010; 24:1229-36. [DOI: 10.1016/j.tiv.2010.02.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2009] [Revised: 01/05/2010] [Accepted: 02/04/2010] [Indexed: 01/05/2023]
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Abstract
Recent investigations on the effects of phyto-oestrogens on various tissues have revealed that these diverse molecules may improve human health, particularly by protecting against certain chronic diseases. After a brief examination of the food sources, structures, and general cellular actions of the major phyto-oestrogens, current research findings on cardiovascular disease, skeletal tissues, and reproductive cancers are reviewed. Phyto-oestrogen concentrations in blood may be maintained at high levels in those consuming soyabean (Glycine max)-based food daily at several meals and exert their effects on target cells through either genomic effects via the classical oestrogen receptors or non-genomic effects mediated by membrane-bound oestrogen receptors or other cellular proteins. The expression of oestrogen receptor (OR) subtypes alpha (a) and beta (beta) varies across tissues, and cells that preferentially express OR-beta, which may include bone cells, are more likely to respond to phyto-oestrogens. Conversely, reproductive tissues contain relatively more OR-a and may, thus, be differently affected by phyto-oestrogens. Soyabean phyto-oestrogens appear to prevent the progression of atherosclerosis through multiple interactions, including lowering of plasma lipids and lipoproteins, increased vasodilatation and, possibly, decreased activation of blood platelets and vascular smooth muscle cells. However, a favourable impact on cardiovascular disease morbidity and mortality by a soyabean-enriched western-type diet remains to be shown, and unresolved questions remain regarding dose and form of the phyto-oestrogens in relation to risks and benefits. The isoflavones of soyabean have been shown consistently to have bone-retentive effects in animal studies by several investigators using rodent models, although intakes must be above a relatively high threshold level for a lengthy period of time, and little or no extra benefit is observed with intakes above this threshold level. The reports of modest or no effects on prevention of bone loss in human and non-human primate studies respectively, may be due to the limited doses tested so far. The relationship between soyabean-food intake and cancer risk has been more extensively investigated than for any other disease, but with less certainty about the benefits of long-term consumption of phyto-oestrogen-containing foods on prevention of cancer. The observations that breast and prostate cancer rates are lower in Asian countries, where soyabean foods are consumed at high levels, and the high isoflavone content of soyabeans have led to examination of the potential protective effects of phyto-oestrogens. Establishing diet-cancer relationships has proved difficult, in part because of the conflicting data from various studies of effects of soyabean-diets on cancer. Epidemiological evidence, though not impressive, does suggest that soyabean intake reduces breast cancer risk. The isoflavone genistein has a potent effect on breast cancer cells in vitro, and early exposure of animals to genistein has been effective in reducing later development of mammary cancer. Thus, continuous consumption of soyabean foods in early life and adulthood may help explain the low breast cancer mortality rates in Asian countries. Although the evidence for a protective effect against prostate cancer may be slightly more supportive, more research is needed before any firm conclusions can be made about the phyto-oestrogen-cancer linkages.
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Affiliation(s)
- J J Anderson
- Department of Nutrition, Schools of Public Health and Medicine, University of North Carolina, Chapel Hill, NC 27599-7400, USA.
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Vasudevan N, Pfaff DW. Non-genomic actions of estrogens and their interaction with genomic actions in the brain. Front Neuroendocrinol 2008; 29:238-57. [PMID: 18083219 DOI: 10.1016/j.yfrne.2007.08.003] [Citation(s) in RCA: 255] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/09/2007] [Accepted: 08/14/2007] [Indexed: 12/16/2022]
Abstract
Ligands for the nuclear receptor superfamily have at least two mechanisms of action: (a) classical transcriptional regulation of target genes (genomic mechanisms); and (b) non-genomic actions, which are initiated at the cell membrane, which could also impact transcription. Though transcriptional mechanisms are increasingly well understood, membrane-initiated actions of these ligands are incompletely understood. This has led to considerable debate over the physiological relevance of membrane-initiated actions of hormones versus genomic actions of hormones, with genomic actions predominating in the endocrine field. There is good evidence that the membrane-limited actions of hormones, particularly estrogens, involve the rapid activation of kinases and the release of calcium and that these are linked to physiologically relevant scenarios in the brain. We show evidence in this review, that membrane actions of estrogens, which activate these rapid signaling cascades, can also potentiate nuclear transcription in both the central nervous system and in non-neuronal cell lines. We present a theoretical scenario which can be used to understand this phenomenon. These signaling cascades may occur in parallel or in series but subsequently, converge at the modification of transcriptionally relevant molecules such as nuclear receptors and/or coactivators. In addition, other non-cognate hormones or neurotransmitters may also activate cascades to crosstalk with estrogen receptor-mediated transcription, though the relevance of this is less clear. The idea that coupling between membrane-initiated and genomic actions of hormones is a novel idea in neuroendocrinology and provides us with a unified view of hormone action in the central nervous system.
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Affiliation(s)
- Nandini Vasudevan
- Cell and Molecular Biology Department, Tulane University, LA 70118, USA.
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Zhang Z, Duan L, Du X, Ma H, Park I, Lee C, Zhang J, Shi J. The proliferative effect of estradiol on human prostate stromal cells is mediated through activation of ERK. Prostate 2008; 68:508-16. [PMID: 18213633 DOI: 10.1002/pros.20722] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
BACKGROUND Estrogen is involved in the development and progression of benign prostatic hyperplasia (BPH). It can stimulate proliferation of prostate stromal cells (PrSCs). However, the exact mechanism remains unclear. METHODS We used the primary cultured human PrSCs and a prostate stromal cell line, WPMY-1, to examine the signaling pathways involved in estrogen-mediated proliferation of PrSCs. Cells were treated with 17beta-estradiol (E(2)) or BSA-E(2). Cell proliferation was assessed by the MTT assay and by cell counting. Western blot analysis was used to determine the status of activation of ERK1/2. RESULTS Results indicated that both E(2) and BSA-E(2) stimulated proliferation of primary PrSCs and WPMY-1 cells. ERK was rapidly activated by E(2) and BSA-E(2). PD98059, which is a selective ERK inhibitor, significantly inhibited estrogen-induced cell proliferation. PrSCs expressed estrogen receptor alpha (ERalpha) and GPR30 but not ERbeta. Small hairpin RNA (shRNA) to ERalpha, but not to GPR30, blocked estrogen-mediated ERK activation and cell proliferation. CONCLUSIONS The results indicated that estrogen could activate ERK pathway through the non-genomic ERalpha pathway, leading to proliferation of PrSCs.
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Affiliation(s)
- Zhisong Zhang
- Department of Biochemistry and Molecular Biology, College of Life Sciences, Nankai University, Tianjin, China
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Watson CS, Alyea RA, Jeng YJ, Kochukov MY. Nongenomic actions of low concentration estrogens and xenoestrogens on multiple tissues. Mol Cell Endocrinol 2007; 274:1-7. [PMID: 17601655 PMCID: PMC1986712 DOI: 10.1016/j.mce.2007.05.011] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/07/2007] [Accepted: 05/17/2007] [Indexed: 10/23/2022]
Abstract
Nongenomic estrogenic mechanisms offer an opportunity to explain the conundrum of environmental estrogen and plant estrogen effects on cells and animals at the very low concentrations which are prevalent in our environments and diets. Heretofore the actions of these compounds have not been adequately accounted for by laboratory tests utilizing assays for actions only via the genomic pathway of steroid action and the nuclear forms of estrogen receptor alpha and beta. Membrane versions of these receptors, and the newly described GPR30 (7TMER) receptor protein provide explanations for the more potent actions of xenoestrogens. The effects of estrogens on many tissues demand a comprehensive assessment of the receptors, receptor levels, and mechanisms that might be involved, to determine which of these estrogen mimetic compounds are harmful and which might even be used therapeutically, depending upon the life stage at which we are exposed to them.
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Affiliation(s)
- C S Watson
- Department of Biochemistry & Molecular Biology, University of Texas Medical Branch, Galveston, TX 77555-0645, USA.
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Wetherill YB, Akingbemi BT, Kanno J, McLachlan JA, Nadal A, Sonnenschein C, Watson CS, Zoeller RT, Belcher SM. In vitro molecular mechanisms of bisphenol A action. Reprod Toxicol 2007; 24:178-98. [PMID: 17628395 DOI: 10.1016/j.reprotox.2007.05.010] [Citation(s) in RCA: 633] [Impact Index Per Article: 37.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2007] [Accepted: 05/18/2007] [Indexed: 11/29/2022]
Abstract
Bisphenol A (BPA, 2,2-bis (4-hydroxyphenyl) propane; CAS# 80-05-7) is a chemical used primarily in the manufacture of polycarbonate plastic, epoxy resins and as a non-polymer additive to other plastics. Recent evidence has demonstrated that human and wildlife populations are exposed to levels of BPA which cause adverse reproductive and developmental effects in a number of different wildlife species and laboratory animal models. However, there are major uncertainties surrounding the spectrum of BPA's mechanisms of action, the tissue-specific impacts of exposures, and the critical windows of susceptibility during which target tissues are sensitive to BPA exposures. As a foundation to address some of those uncertainties, this review was prepared by the "In vitro" expert sub-panel assembled during the "Bisphenol A: An Examination of the Relevance of Ecological, In vitro and Laboratory Animal Studies for Assessing Risks to Human Health" workshop held in Chapel Hill, NC, Nov 28-29, 2006. The specific charge of this expert panel was to review and assess the strength of the published literature pertaining to the mechanisms of BPA action. The resulting document is a detailed review of published studies that have focused on the mechanistic basis of BPA action in diverse experimental models and an assessment of the strength of the evidence regarding the published BPA research.
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Affiliation(s)
- Yelena B Wetherill
- Department of Environmental Health, Harvard School of Public Health, Boston, MA 02115, USA
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Abstract
Hormonal ligands for the nuclear receptor superfamily have at least two interacting mechanisms of action: 1) classical transcriptional regulation of target genes (genomic mechanisms); and 2) nongenomic actions that are initiated at the cell membrane, which could impact transcription. Although transcriptional mechanisms are increasingly well understood, membrane-initiated actions of these ligands are incompletely understood. Historically, this has led to a considerable divergence of thought in the molecular endocrine field. We have attempted to uncover principles of hormone action that are relevant to membrane-initiated actions of estrogens. There is evidence that the membrane-limited actions of hormones, particularly estrogens, involve the rapid activation of kinases and the release of calcium. Membrane actions of estrogens, which activate these rapid signaling cascades, can also potentiate nuclear transcription. These signaling cascades may occur in parallel or in series but subsequently converge at the level of modification of transcriptionally relevant molecules such as nuclear receptors and/or coactivators. In addition, other hormones or neurotransmitters may also activate cascades to crosstalk with estrogen receptor-mediated transcription. The idea of synergistic coupling between membrane-initiated and genomic actions of hormones fundamentally revises the paradigms of cell signaling in neuroendocrinology.
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Affiliation(s)
- Nandini Vasudevan
- Department of Biology, Pennsylvania State University, University Park, Pennsylvania 16802, USA.
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Xenoestrogens are potent activators of nongenomic estrogenic responses. Steroids 2006; 72:124-34. [PMID: 17174995 DOI: 10.1016/j.steroids.2006.11.002] [Citation(s) in RCA: 114] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/24/2006] [Revised: 10/31/2006] [Accepted: 11/03/2006] [Indexed: 01/28/2023]
Abstract
Studies of the nuclear transcriptional regulatory activities of non-physiological estrogens have not explained their actions in mediating endocrine disruption in animals and humans at the low concentrations widespread in the environment. However, xenoestrogens have rarely been tested for their ability to participate in the plethora of nongenomic steroid signaling pathways elucidated over the last several years. Here we review what is known about such responses in comparison to our recent evidence that xenoestrogens can rapidly and potently elicit signaling through nongenomic pathways culminating in functional endpoints. Both estradiol (E(2)) and compounds representing various classes of xenoestrogens (diethylstilbestrol, coumestrol, bisphenol A, DDE, nonylphenol, endosulfan, and dieldrin) act via a membrane version of the estrogen receptor-alpha on pituitary cells, and can provoke Ca(2+) influx via L-type channels, leading to prolactin (PRL) secretion. These hormones and mimetics can also cause the oscillating activation of extracellular regulated kinases (ERKs). However, individual estrogen mimetics differ in their potency and temporal phasing of these activations compared to each other and to E(2). It is perhaps in these ways that they disrupt some endocrine functions when acting in combination with physiological estrogens. Our quantitative assays allow comparison of these outcomes for each mimetic, and let us build a detailed picture of alternative signaling pathway usage. Such an understanding should allow us to determine the estrogenic or antiestrogenic potential of different types of xenoestrogens, and help us to develop strategies for preventing xenoestrogenic disruption of estrogen action in many tissues.
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Ropero AB, Alonso-Magdalena P, Ripoll C, Fuentes E, Nadal A. Rapid endocrine disruption: environmental estrogen actions triggered outside the nucleus. J Steroid Biochem Mol Biol 2006; 102:163-9. [PMID: 17084624 DOI: 10.1016/j.jsbmb.2006.09.019] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
An exogenous substance is defined as an endocrine disrupter chemical (EDC) if it alters the function of the endocrine system provoking adverse health effects. Environmental estrogens are the most studied EDCs. They follow the same mechanisms of action as the gonadal hormone 17beta-estradiol. Up to now, the estrogenicity of environmental estrogenic pollutants has been based on the property of these compounds to bind to estrogen receptors (ERs), either ERalpha or ERbeta, and to act subsequently as transcription factors when binding to the estrogen response element (ERE) in the DNA. All the estrogenic bioassays currently used are based on this mechanism of action. New evidence indicates that the definition of estrogenicity for a chemical should take into account other estrogen receptors as well as new signaling pathways. These include the activation of additional transcription factors as well as the action of xenoestrogens through estrogen receptors located outside the nucleus: in the plasma membrane, mitochondria and probably the cytosol. Therefore, new estrogenic bioassays should be developed to include the novel concept of rapid endocrine disruption.
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Affiliation(s)
- Ana B Ropero
- Instituto de Bioingeniería, Universidad Miguel Hernández de Elche, 03202 Elche, Alicante, Spain
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Singh M, Dykens JA, Simpkins JW. Novel mechanisms for estrogen-induced neuroprotection. Exp Biol Med (Maywood) 2006; 231:514-21. [PMID: 16636299 DOI: 10.1177/153537020623100505] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Estrogens are gonadal steroid hormones that are present in the circulation of both males and females and that can no longer be considered within the strict confines of reproductive function. In fact, the bone, the cardiovascular system, and extrahypothalamic regions of the brain are now well-established targets of estrogens. Among the numerous aspects of brain function regulated by estrogens are their effects on mood, cognitive function, and neuronal viability. Here, we review the supporting evidence for estrogens as neuroprotective agents and summarize the various mechanisms that may be involved in this effect, focusing particularly on the mitochondria as an important target. On the basis of this evidence, we discuss the clinical applicability of estrogens in treating various age-related disorders, including Alzheimer disease and stroke, and identify the caveats that must be considered.
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Affiliation(s)
- Meharvan Singh
- Department of Pharmacology & Neuroscience, University of North Texas Health Science Center, Fort Worth, TX 76107, USA.
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Zivadinovic D, Watson CS. Membrane estrogen receptor-alpha levels predict estrogen-induced ERK1/2 activation in MCF-7 cells. Breast Cancer Res 2004; 7:R130-44. [PMID: 15642162 PMCID: PMC1064105 DOI: 10.1186/bcr959] [Citation(s) in RCA: 85] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2004] [Revised: 08/18/2004] [Accepted: 10/07/2004] [Indexed: 12/19/2022] Open
Abstract
INTRODUCTION We examined the participation of a membrane form of estrogen receptor (mER)-alpha in the activation of mitogen-activated protein kinases (extracellular signal-regulated kinase [ERK]1 and ERK2) related to cell growth responses in MCF-7 cells. METHODS We immunopanned and subsequently separated MCF-7 cells (using fluorescence-activated cell sorting) into mER-alpha-enriched (mERhigh) and mER-alpha-depleted (mERlow) populations. We then measured the expression levels of mER-alpha on the surface of these separated cell populations by immunocytochemical analysis and by a quantitative 96-well plate immunoassay that distinguished between mER-alpha and intracellular ER-alpha. Western analysis was used to determine colocalized estrogen receptor (ER)-alpha and caveolins in membrane subfractions. The levels of activated ERK1 and ERK2 were determined using a fixed cell-based enzyme-linked immunosorbent assay developed in our laboratory. RESULTS Immunocytochemical studies revealed punctate ER-alpha antibody staining of the surface of nonpermeabilized mERhigh cells, whereas the majority of mERlow cells exhibited little or no staining. Western analysis demonstrated that mERhigh cells expressed caveolin-1 and caveolin-2, and that ER-alpha was contained in the same gradient-separated membrane fractions. The quantitative immunoassay for ER-alpha detected a significant difference in mER-alpha levels between mERhigh and mERlow cells when cells were grown at a sufficiently low cell density, but equivalent levels of total ER-alpha (membrane plus intracellular receptors). These two separated cell subpopulations also exhibited different kinetics of ERK1/2 activation with 1 pmol/l 17beta-estradiol (E2), as well as different patterns of E2 dose-dependent responsiveness. The maximal kinase activation was achieved after 10 min versus 6 min in mERhigh versus mERlow cells, respectively. After a decline in the level of phosphorylated ERKs, a reactivation was seen at 60 min in mERhigh cells but not in mERlow cells. Both 1A and 2B protein phosphatases participated in dephosphorylation of ERKs, as demonstrated by efficient reversal of ERK1/2 inactivation with okadaic acid and cyclosporin A. CONCLUSION Our results suggest that the levels of mER-alpha play a role in the temporal coordination of phosphorylation/dephosphorylation events for the ERKs in breast cancer cells, and that these signaling differences can be correlated to previously demonstrated differences in E2-induced cell proliferation outcomes in these cell types.
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Affiliation(s)
- Dragoslava Zivadinovic
- Department of Human Biological Chemistry and Genetics, University of Texas Medical Branch, Galveston, Texas, USA
| | - Cheryl S Watson
- Department of Human Biological Chemistry and Genetics, University of Texas Medical Branch, Galveston, Texas, USA
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19
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Bulayeva NN, Watson CS. Xenoestrogen-induced ERK-1 and ERK-2 activation via multiple membrane-initiated signaling pathways. ENVIRONMENTAL HEALTH PERSPECTIVES 2004; 112:1481-7. [PMID: 15531431 PMCID: PMC1325963 DOI: 10.1289/ehp.7175] [Citation(s) in RCA: 102] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Xenoestrogens can mimic or antagonize the activity of physiological estrogens, and the suggested mechanism of xenoestrogen action involves binding to estrogen receptors (ERs). However, the failure of various in vitro or in vivo assays to show strong genomic activity of xenoestrogens compared with estradiol (E2) makes it difficult to explain their ability to cause abnormalities in animal (and perhaps human) reproductive functions via this pathway of steroid action. E2 has also been shown to initiate rapid intracellular signaling, such as changes in levels of intracellular calcium, cAMP, and nitric oxide, and activations of a variety of kinases, via action at the membrane. In this study, we demonstrate that several xenoestrogens can rapidly activate extracellular-regulated kinases (ERKs) in the pituitary tumor cell line GH3/B6/F10, which expresses high levels of the membrane receptor for ER-alpha (mER). We tested a phytoestrogen (coumestrol), organochlorine pesticides or their metabolites (endosulfan, dieldrin, and DDE), and detergent by-products of plastics manufacturing (p-nonylphenol and bisphenol A). These xenoestrogens (except bisphenolA) produced rapid (3-30 min after application), concentration (10(-14)-10(-8) M)-dependent ERK-1/2 phosphorylation but with distinctly different activation patterns. To identify signaling pathways involved in ERK activation, we used specific inhibitors of ERs, epidermal growth factor receptors, Ca2+ signaling, Src and phosphoinositide-3 kinases, and a membrane structure disruption agent. Multiple inhibitors blocked ERK activation, suggesting simultaneous use of multiple pathways and complex signaling web interactions. However, inhibitors differentially affected each xenoestrogen response examined. These actions may help to explain the distinct abilities of xenoestrogens to disrupt reproductive functions at low concentrations.
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Affiliation(s)
- Nataliya N Bulayeva
- Department of Human Biological Chemistry and Genetics, University of Texas Medical Branch, Galveston, Texas 77555-0645, USA
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20
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Watson CS, Gametchu B. Proteins of multiple classes may participate in nongenomic steroid actions. Exp Biol Med (Maywood) 2004; 228:1272-81. [PMID: 14681543 PMCID: PMC1224708 DOI: 10.1177/153537020322801106] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Responses to steroids initiated from non-nuclear receptors impinge on a wide variety of cellular responses and utilize nearly all known signal transduction webs. While the mechanisms by which steroid receptors localize in the membrane are still unclear, it is apparent that this alternative localization allows steroid receptors to participate in a wide range of complex functions influencing cell proliferation, death, and differentiation. The central debate still remains the identity of the protein class or classes that mediate membrane-initiated (nongenomic) responses. The data thus far have supported several possibilities, including: nuclear steroid receptor-like forms in non-nuclear locations; other known (nonsteroid) membrane receptors or channels with additional steroid-binding sites; enzymes; transporters; receptors for serum steroid-binding proteins; unique and previously undescribed proteins; or chimeras of typical steroid receptor domains with other unique or known protein domains. Categorizing membrane steroid receptor proteins based exclusively on the actions of antagonists and agonists, without considering cell context and protein partnering issues, may mislead us into predicting more receptor subtypes than really exist. However, the plethora of signaling and functional outcomes may indicate the participation of more than one kind of steroid-binding protein. Resolving such unanswered questions will require future investigative focus on this alternative arm of steroid action, which is likely to yield as many therapeutic opportunities as have nuclear steroid mechanisms.
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Affiliation(s)
- Cheryl S Watson
- Department of Human Biological Chemistry and Genetics, University of Texas, Medical Branch, Galveston, Texas 77555, USA.
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21
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Mize AL, Young LJ, Alper RH. Uncoupling of 5-HT1A receptors in the brain by estrogens: regional variations in antagonism by ICI 182,780. Neuropharmacology 2003; 44:584-91. [PMID: 12668044 DOI: 10.1016/s0028-3908(03)00044-3] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Previously we have shown that 17beta-estradiol (in vivo and in vitro) rapidly decreases the function of serotonin(1A) (5-HT(1A)) receptors, allowing us to hypothesize that 17beta-estradiol accomplished this via activation of a membrane estrogen receptor. Hippocampus and frontal cortex obtained from ovariectomized rats were incubated with 17beta-estradiol or bovine serum albumin (BSA)-estradiol in the presence or absence of the estrogen receptor (ER) antagonist ICI 182,780. Membranes were prepared to measure R(+)8-OH-DPAT-stimulated [(35)S]GTPgammaS binding (a measure of 5-HT(1A) receptor coupling and function). In both hippocampus and frontal cortex, 17beta-estradiol and BSA-estradiol (50 nM) decreased R(+)8-OH-DPAT-stimulated [(35)S]GTPgammaS binding. ICI 182,780 blocked the effect of both the estrogens in hippocampus, but only the effect of 17beta-estradiol in frontal cortex. Due to the inability of ICI 182,780 to block the effects of BSA-estradiol in frontal cortex, similar experiments were performed using the selective estrogen receptor modulator tamoxifen as the agonist. Tamoxifen (100 nM and 1 microM) decreased R(+)8-OH-DPAT-stimulated [(35)S]GTPgammaS binding. ICI 182,780 (1 microM) blocked the ability of tamoxifen to decrease 5-HT(1A) receptor coupling in the hippocampus, but not in the frontal cortex. Taken together, these data support the existence of a pharmacologically distinct ER in hippocampus vs. frontal cortex that might be responsible for rapid uncoupling of 5-HT(1A) receptors.
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Affiliation(s)
- A L Mize
- Department of Pharmacology, Toxicology and Therapeutics, The University of Kansas School of Medicine, Kansas City, USA
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22
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CAMPBELL CELESTEH, BULAYEVA NATALIYA, BROWN DAVIDB, GAMETCHU BAHIRU, WATSON CHERYLS. Regulation of the membrane estrogen receptor-alpha: role of cell density, serum, cell passage number, and estradiol. FASEB J 2002; 16:1917-27. [PMID: 12468456 PMCID: PMC1266276 DOI: 10.1096/fj.02-0182com] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
We used modified immunocytochemical conditions to quantify a membrane form of estrogen receptor-alpha (mERalpha) in a rat pituitary tumor cell line, GH3/B6/F10. We studied the regulation of mERalpha vs. levels of intracellular ERalpha (iERalpha) using our 96-well plate immunoassay. The anti-ERalpha antibody C542 was used to label the ERalpha (via conjugated alkaline phosphatase) in fixed permeabilized (for iERalpha) vs. nonpermeabilized cells (for mERalpha). Expression of mERalpha was highest at low cell densities (<1000 cells/well) and decreased significantly at densities where cellular processes touched, whereas the more abundant iERalpha increased with increasing cell density over the same range. Serum starvation for 48 h caused increases in mERalpha, whereas iERalpha levels showed no significant changes. A large decline in mERalpha and iERalpha levels with cell passage number was observed. Minutes after nM 17beta-estradiol (E2) treatment, a portion of the cells rounded up and detached from the culture plate, whereas nM cholesterol had no such effect. Although E2 treatment did not change mERalpha levels, the antigen was reorganized from a fine particulate to aggregation into asymmetric large granules of staining. That common culturing conditions favor down-regulation of mERalpha may explain the relatively few reports of this protein in other experimental systems.
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Affiliation(s)
- CELESTE H. CAMPBELL
- Human Biological Chemistry and Genetics Department, University of Texas, Medical Branch, Galveston Texas, USA; and
| | - NATALIYA BULAYEVA
- Human Biological Chemistry and Genetics Department, University of Texas, Medical Branch, Galveston Texas, USA; and
| | - DAVID B. BROWN
- Human Biological Chemistry and Genetics Department, University of Texas, Medical Branch, Galveston Texas, USA; and
| | - BAHIRU GAMETCHU
- Department of Pediatrics, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
| | - CHERYL S. WATSON
- Human Biological Chemistry and Genetics Department, University of Texas, Medical Branch, Galveston Texas, USA; and
- Correspondence: Department of Human Biological Chemistry and Genetics, University of Texas, Medical Branch, Galveston, TX 77555-0645, USA. E-mail:
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23
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Benassayag C, Perrot-Applanat M, Ferre F. Phytoestrogens as modulators of steroid action in target cells. J Chromatogr B Analyt Technol Biomed Life Sci 2002; 777:233-48. [PMID: 12270216 DOI: 10.1016/s1570-0232(02)00340-9] [Citation(s) in RCA: 120] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Although numerous reports exist on the potential beneficial role of nutritional phytoestrogens in human health, their molecular mechanism in target cells is still not completely understood. Phytoestrogens promote estrogen and antiestrogen effects by interacting with numerous molecules, carrier proteins, enzymes and membrane and nuclear receptors, directly or indirectly involved in the transfer of estrogen signals. The hypothesis that the ER beta subtype plays a key role in antiproliferative effect of phytoestrogens, especially in breast cancer, is examined here. This review focus on the effects of phytoestrogens in developmental processes such as those linked to reproductive function, tumorigenesis and angiogenesis.
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Affiliation(s)
- C Benassayag
- U361 INSERM, Université Paris V, Pavillon Baudelocque, Port Royal Cochin, Paris, France
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24
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Cossette LJ, Gaumond I, Martinoli MG. Combined effect of xenoestrogens and growth factors in two estrogen-responsive cell lines. Endocrine 2002; 18:303-8. [PMID: 12450323 DOI: 10.1385/endo:18:3:303] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
It is now well recognized that estrogenic signaling mechanisms are far more complex than once thought. Several crosstalks between the estrogen receptor and other signaling pathways may influence the estrogenic stimulation of cell growth. Thus, the estrogenic effects of several environmental contaminants, now suspected to act as endocrine disrupters, may be influenced by a simultaneous stimulation of other signaling pathways. The aim of this study was to investigate whether the growth response of two estrogen-responsive cell lines, MCF-7 and GH3, treated with xenoestrogens might be affected by the addition of growth factors to their culture medium. Cells were treated with two known xenoestrogens, endosulfan and chlordane, alone or in the presence of insulin-like growth factor-1 and epidermal growth factor, respectively, and their growth was measured using the 2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxyanilide proliferation assay. Our results show that treatment with endosulfan or chlordane as well as treatment with growth factors increased cell growth, while the administration of xenoestrogens together with growth factors triggered a partly additive response with no antagonist or synergistic effect. These results sustain a role for xenoestrogens in cellular growth.
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Affiliation(s)
- Louis J Cossette
- Department of Biochemistry, Université du Québec à Trois-Rivières, Trois-Rivières, Québec, Canada
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25
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Singh S, Shaul PW, Gupta PD. Conventional estrogen receptors are found in the plasma membrane of vaginal epithelial cells of the rat. Steroids 2002; 67:757-64. [PMID: 12123787 DOI: 10.1016/s0039-128x(02)00028-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Estrogens induce rapid (non-genomic) and delayed (genomic) effects on the target cells. The early effects include induction of signal transduction pathway within seconds, whereas the delayed responses require hours and involve transcription and translation. The rapid effects of estradiol (E) on the vaginal epithelial cells (VEC) involved calcium uptake within seconds via the induction of phosphoinositol lipid metabolism as reported in our earlier studies. In this study, we demonstrate the presence of classical estrogen receptors (ER) on the plasma membrane of VEC of the rats. Immunoreactive bands of 67, 56 and 35 kDa are detectable in the membrane fractions (mf) using antibodies recognizing different epitopes of ER alpha. We have also been able to purify a protein having a mass of 67 kDa from the detergent-soluble fraction of the plasma membrane of VEC, which shows properties identical to the classical receptor purified from the cytosolic fraction of the cells. The membrane receptors get dissociated upon binding to the ligand. Besides a role in signal transduction events induced by estradiol, the membrane estrogen receptors may have an important role to play in translocation of the steroid to the cytosolic compartment.
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Affiliation(s)
- Shashi Singh
- Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad 500007, India.
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26
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Abstract
Many studies have demonstrated the nuclear forms of steroid receptors and their activities, while fewer investigators have identified and described the membrane forms of these receptors. Our immuno-identification approaches for the qualitative and quantitative comparison of the membrane form of the estrogen receptor-alpha (mER alpha) to its nuclear counterpart now allow us to address questions about the comparative levels and regulation of these receptor forms. ER alpha-specific antisense oligonucleotides eliminate mER alpha expression, while only mildly reducing the nuclear ER alpha. Success of immuno-identification for the mER alpha is very sensitive to different fixation protocols, affecting cell permeability (and thus distinction from the intracellular form) and differential epitope preservation. All such identifications must be accompanied by proof of cell membrane integrity and focal plane assessments. The mER alpha expression on selected cells declines rapidly with cell passage number and cell density. Expression of mER alpha is enhanced by serum starvation and selection for specific phases of the cell cycle. The hinge region of the protein is sensitive to ligand-induced epitope masking and to antibody-induced changes in receptor-mediated responses. Responsive cells are often diluted within cell populations by loss of the membrane receptor form. The bimodality of the rapid estrogen action, with inhibitory doses between picomolar and nanomolar stimulatory concentrations, requires detailed dose-response curves. Finally, responsive cells can be lost from assays, as upon estrogen treatment they rapidly round up and leave the substrates to which they are attached. These regulatory phenomena demonstrate that levels of the membrane form of the estrogen receptor are very dynamic.
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Affiliation(s)
- Cheryl S Watson
- Human Biological Chemistry and Genetics Department, University of Texas Medical Branch, Galveston, TX 77555, USA.
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27
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Sutter-Dub MT. Rapid non-genomic and genomic responses to progestogens, estrogens, and glucocorticoids in the endocrine pancreatic B cell, the adipocyte and other cell types. Steroids 2002; 67:77-93. [PMID: 11755172 DOI: 10.1016/s0039-128x(01)00142-8] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Rapid biologic responses to injected steroids were described as early as 60 years ago. More recently, evidence has been presented that 17beta-estradiol given i.v. will double the uterine cAMP activity within 15 s (Proc Natl Acad Sci USA 1967;58:1711-8), and also that estrogens will bind to the outer surfaces of endometrial cells (Nature 1977;265:69-72), suggesting that these steroids can both engage and direct intracellular events. Unfortunately, studies of such rapid membrane effects of steroids have languished due to the accumulation of compelling data for the more slowly manifest actions of these compounds at the level of nuclear DNA. We report a number of observations in women, in experimental animals, and in isolated organ or cell systems using 17beta-estradiol, progesterone or glucocorticoids which provide ample evidence for rapid intracellular metabolic responses to these steroids, mediated by their actions at the cellular plasma membrane. Such rapid responses have been shown in various classic targets or not, such as the B cell of the endocrine pancreas and the fat cell. They involve plasma membrane binding, changes in membrane electrical activity, Ca2+ handling, G and Ras proteins, cAMP, cGMP, IP(3), DAG, phosphodiesterases, protein kinases, tyrosine kinases, ER kinases, and mitogen activated protein kinases (MAPks) and nitric oxide synthase. These recent findings are discussed in detail and should lead to a fuller understanding of the cellular effects of the steroid hormones.
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Affiliation(s)
- Marie Thérèse Sutter-Dub
- Université Bordeaux I, UFR de Biologie, Laboratoire d'Endocrinologie cellulaire: Mécanismes d'action d'hormones stéroides, Avenue des Facultés, F-33405 Talence Cedex, France.
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28
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Watson CS, Gametchu B. Membrane estrogen and glucocorticoid receptors--implications for hormonal control of immune function and autoimmunity. Int Immunopharmacol 2001; 1:1049-63. [PMID: 11407301 DOI: 10.1016/s1567-5769(01)00036-4] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Membrane steroid receptors (mSRs) have recently re-emerged as candidates for mediating steroid effects which do not fit the paradigm of nuclear transcription factor mechanisms. We have studied two steroid-binding classes of mSRs, and have noted striking similarities in their characteristics (immunocytochemical appearance, biochemical properties, proteolytic sensitivity, signaling pathways, regulation, and molecular origins). These observations strengthen the conclusion that mSRs can be modified versions of intracellular steroid receptors. The membrane estrogen receptors (mERs) we studied are involved in estrogen-induced release of prolactin. Membrane glucocorticoid receptors (mGRs) in both mouse and human lymphoma cells are necessary for the initiation of glucocorticoid-induced therapeutic apoptosis which is related to the developmental phenomenon of thymic involution. Diseases of autoimmunity such as systemic lupus erythematosus and arthritis are related to estrogen status. Since both of these mSRs have recently been found in both normal and cancerous lymphoid cells, actions of these mSRs may have important consequences for functions and diseases of the immune system. Therefore, the study of these forms of steroid receptors may present novel therapeutic opportunities for the use of steroids and steroid analogs.
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Affiliation(s)
- C S Watson
- Human Biological Chemistry and Genetics Department, University of Texas Medical Branch, Route 0645, Galveston, TX 77555-0645, USA.
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Powell CE, Soto AM, Sonnenschein C. Identification and characterization of membrane estrogen receptor from MCF7 estrogen-target cells. J Steroid Biochem Mol Biol 2001; 77:97-108. [PMID: 11377974 DOI: 10.1016/s0960-0760(01)00040-1] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Estrogens control the proliferation of estrogen-target cells through a receptor mediated pathway. We have recently presented evidence that estradiol cancels the proliferative inhibition exerted by albumin on estrogen-target cells (indirect-negative hypothesis). We postulate that this mechanism requires the presence of a membrane estrogen receptor (mER)-membrane albumin receptor complex. Confirmation for mERalpha in MCF7 cells is now made using both the C542 monoclonal and ER-21 polyclonal antibodies (Ab)s specific for ERalpha. Western blot analysis of purified membrane proteins with ERalpha Abs revealed multiple high M(r) mERs (92 k, 110 k, and 130 k M(r)), as well as a 67 k M(r) mER; immunoreactive proteins were competed by inclusion of 500-fold molar excess C542 peptide. Ligand blot analysis of similar extracts with estradiol-peroxidase identified several potential mERs as well; two of these proteins were also recognized by C542 and ER-21 Abs (110 and 67 k M(r)). Fluorescence, confocal and electron microscopy of MCF7 cells fixed in 2.0% paraformaldehyde/0.1% glutaraldehyde identified specific mERalpha sites by immunocytochemistry. Specific binding of 3H-17beta-estradiol was reduced by a 200-fold molar excess of unlabeled 17beta-estradiol, but not by testosterone and progesterone. These results suggest that the ER on the plasma membrane of MCF7 cells is similar, but not identical to its intracellular counterpart. We propose that the observed mER actively participates in the estrogen-mediated proliferation of MCF7 cells.
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Affiliation(s)
- C E Powell
- Department of Anatomy and Cellular Biology, Tufts University School of Medicine, 136 Harrison Avenue, Boston, MA 02111, USA
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30
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Abstract
Platelets play an important role in the coronary thrombus formation that leads to myocardial ischemia and infarction. Gender differences in the development of coronary heart disease and its outcomes are partly regulated by estrogen and its receptors, but the roles of the latter in thrombogenicity are less well-defined. We previously demonstrated the presence of estrogen receptor (ER) beta in cells of the megakaryocytic lineage. In this study, we characterize human platelet ERbeta and its expression using biochemical and molecular biological techniques. Western immunoblotting showed that platelet ERbeta migrated with an apparent molecular mass approximately 3.7 kDa larger than ERbeta in a variety of cell lines (including those of prostate and breast origin). A rigorous investigation of platelet ERbeta mRNA by reverse transcriptase-polymerase chain reaction revealed normal transcripts and a single alternately spliced mRNA. However, this variant form was smaller, lacking exon 2, and could not account for the larger protein size seen in platelets. Treatment of ERbeta with N-glycosidase F, which removes core carbohydrate residues, caused a more rapid migration through polyacrylamide gels but had no effect on ERbeta from human cell lines. We conclude that the larger form of ERbeta in human platelets is not attributable to alternate mRNA splicing but primarily to tissue-specific glycosylation.
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Affiliation(s)
- M L Nealen
- Department of Medicine, Program in Cellular and Molecular Medicine, Johns Hopkins University School of Medicine, Baltimore, Md, USA
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31
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Son HY, Nishikawa A, Ikeda T, Furukawa F, Hirose M. Lack of modification by environmental estrogenic compounds of thyroid carcinogenesis in ovariectomized rats pretreated with N-bis(2-hydroxypropyl)nitrosamine (DHPN). Jpn J Cancer Res 2000; 91:966-72. [PMID: 11050465 PMCID: PMC5926253 DOI: 10.1111/j.1349-7006.2000.tb00872.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
The effects of environmental estrogenic compounds, soy isoflavone mixture (SI), genistein (GEN), and nonylphenol (NP), and the possible goitrogen 3-chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone (MX), on thyroid carcinogenesis were investigated in ovariectomized (OVX) female rats. Five-week-old OVX F344 rats were given a single subcutaneous injection of N-bis(2-hydroxypropyl)nitrosamine (DHPN; 2400 mg / kg, body weight) or vehicle alone. Starting 1 week later, GEN (250 or 25 ppm in diet), SI (400 ppm in diet), NP (250 or 25 ppm in diet), MX (30 ppm, in drinking water), sulfadimethoxine (SDM), a known thyroid tumor-promoter (1000 ppm in drinking water), or beta-estradiol 3-benzoate (EB), a synthetic estrogen (0.5 mg in cholesterol pellet, s.c.) were administered for 12 weeks. SDM and EB were included as positive controls. At sacrifice the major organs including the thyroid, pituitary, liver, kidney, uterus, vagina, brain and pancreas were collected and histopathological observation was performed. Thyroid weights were significantly increased (P < 0. 001) only in the SDM treatment group and pituitary weights were elevated with SDM (P < 0.05) and EB (P < 0.001). Kidney and uterus weights were also significantly increased (P < 0.05) by EB. Histopathologically, proliferative lesions of the thyroid were only observed in the SDM treatment group and of the pituitary in the SDM or EB treatment groups. Renal tubule lesions, uterine squamous metaplasia, vaginal keratinization and telangiectasia of pancreatic islets were also observed with EB. There were no organ weight changes or histopathological lesions in the major organs, including the thyroid, in the GEN, SI, MX or NP treatment groups. Our results thus indicated a lack of modifying effects on thyroid carcinogenesis in female OVX rats, in agreement with our previous finding in males.
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Affiliation(s)
- H Y Son
- Division of Pathology, National Institute of Health Sciences, Setagaya-ku, Tokyo 158-8501, Japan.
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32
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Son HY, Nishikawa A, Ikeda T, Nakamura H, Miyauchi M, Imazawa T, Furukawa F, Hirose M. Lack of modifying effects of environmental estrogenic compounds on the development of thyroid proliferative lesions in male rats pretreated with N-bis(2-hydroxypropyl)nitrosamine (DHPN). Jpn J Cancer Res 2000; 91:899-905. [PMID: 11011117 PMCID: PMC5926451 DOI: 10.1111/j.1349-7006.2000.tb01032.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
The modifying effects of various environmental estrogenic compounds on thyroid carcinogenesis were investigated in a rodent two-stage carcinogenesis model. The compounds examined were a soy isoflavone mixture (SI) and genistein (GEN) as phytoestrogens, nonylphenol (NP) as a xenoestrogen, 3-chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone (MX) as a thyroid carcinogen and sulfadimethoxine (SDM) as a known thyroid tumor promoter. Five-week-old male F344 rats were given a single subcutaneous injection of N-bis(2-hydroxypropyl)nitrosamine (DHPN; 2800 mg / kg, body weight) or the vehicle alone. Starting one week thereafter, GEN (250 or 25 ppm in diet), SI (400 ppm in diet), NP (250 or 25 ppm in diet), MX (30 ppm, in drinking water) or SDM (1000 ppm in drinking water) was administered for 12 weeks. Major organs including the thyroid, pituitary, liver, kidney, testis, brain and pancreas were weighed and histopathological observation was performed. Thyroid weights were significantly increased (P < 0.001) only in the SDM treatment groups, especially with DHPN pretreatment. Kidney weights were slightly increased in the NP or MX treatment groups, albeit without statistical significance. Histopathologically, thyroid proliferative lesions were only observed in the SDM alone or DHPN + SDM group with significant focal hyperplasias, adenomas and adenocarcinomas limited to the combined treatment case. There were no organ weight changes or histopathological lesions in the major organs including the thyroid in the GEN, SI, NP, and MX treatment groups regardless of DHPN pretreatment. Our results thus indicate that the weakly estrogenic compounds GEN, SI and NP and the environmental rat thyroid carcinogen MX do not exert any modifying effects on thyroid carcinogenesis in rats under the present experimental conditions.
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Affiliation(s)
- H Y Son
- Division of Pathology, National Institute of Health Sciences, Setagaya-ku, Tokyo 158-8501, Japan.
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Fang H, Tong W, Perkins R, Soto AM, Prechtl NV, Sheehan DM. Quantitative comparisons of in vitro assays for estrogenic activities. ENVIRONMENTAL HEALTH PERSPECTIVES 2000; 108:723-9. [PMID: 10964792 PMCID: PMC1638296 DOI: 10.1289/ehp.00108723] [Citation(s) in RCA: 137] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Substances that may act as estrogens show a broad chemical structural diversity. To thoroughly address the question of possible adverse estrogenic effects, reliable methods are needed to detect and identify the chemicals of these diverse structural classes. We compared three assays--in vitro estrogen receptor competitive binding assays (ER binding assays), yeast-based reporter gene assays (yeast assays), and the MCF-7 cell proliferation assay (E-SCREEN assay)--to determine their quantitative agreement in identifying structurally diverse estrogens. We examined assay performance for relative sensitivity, detection of active/inactive chemicals, and estrogen/antiestrogen activities. In this examination, we combined individual data sets in a specific, quantitative data mining exercise. Data sets for at least 29 chemicals from five laboratories were analyzed pair-wise by X-Y plots. The ER binding assay was a good predictor for the other two assay results when the antiestrogens were excluded (r(2) is 0.78 for the yeast assays and 0.85 for the E-SCREEN assays). Additionally, the examination strongly suggests that biologic information that is not apparent from any of the individual assays can be discovered by quantitative pair-wise comparisons among assays. Antiestrogens are identified as outliers in the ER binding/yeast assay, while complete antagonists are identified in the ER binding and E-SCREEN assays. Furthermore, the presence of outliers may be explained by different mechanisms that induce an endocrine response, different impurities in different batches of chemicals, different species sensitivity, or limitations of the assay techniques. Although these assays involve different levels of biologic complexity, the major conclusion is that they generally provided consistent information in quantitatively determining estrogenic activity for the five data sets examined. The results should provide guidance for expanded data mining examinations and the selection of appropriate assays to screen estrogenic endocrine disruptors.
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Affiliation(s)
- H Fang
- Division of Genetic and Reproductive Toxicology, National Center for Toxicological Research (NCTR), Jefferson, Arkansas, USA.
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Russell KS, Haynes MP, Sinha D, Clerisme E, Bender JR. Human vascular endothelial cells contain membrane binding sites for estradiol, which mediate rapid intracellular signaling. Proc Natl Acad Sci U S A 2000; 97:5930-5. [PMID: 10823945 PMCID: PMC18536 DOI: 10.1073/pnas.97.11.5930] [Citation(s) in RCA: 289] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Estrogen induces both rapid and delayed effects on the cardiovascular system. The early effects take place within minutes (e.g., changes in vasomotor tone) and are mediated through rapid intracellular signaling pathways; whereas the delayed effects (e.g., remodeling or lipid alterations) require hours to days to occur and require transcriptional effects with subsequent modulation of protein expression. To study the acute effects of 17beta-estradiol (E2) treatment on vascular function, we have investigated the rapid (on the order of minutes) effects of E2 treatment on intracellular signaling in human endothelial cells (EC). Our previous data have shown that E2 induces rapid release of NO from and activation of guanylate cyclase in human EC. In this study, we demonstrate that E2 also activates mitogen-activated protein kinase (extracellular signal-related kinase) signaling within minutes in EC. We hypothesized that this effect might be mediated by estrogen receptors (ER) localized to the cell surface. Our data show that membrane-impermeant forms of E2 also activate EC mitogen-activated protein kinase as well as stimulate cGMP production and NO release. The ER antagonist ICI 182,780 blocks this effect. Using confocal microscopy and flow cytometric analysis, we demonstrate that EC contain surface binding sites for E2, detectable by cell-impermeant ligand binding and equally with an anti-ERalpha antibody. Immunoreactive bands of 66 and 45 kDa are detectable with an anti-ERalpha mAb in human EC, and their individual presence correlates functionally with E2-stimulated genomic and rapid nongenomic responses, respectively. Membrane ERs may provide key molecular switches in these novel, rapid signaling pathways induced by E2 in EC.
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Affiliation(s)
- K S Russell
- Division of Cardiovascular Medicine and Molecular Cardiobiology, Boyer Center for Molecular Medicine, Yale University School of Medicine, New Haven, CT 06536-0812, USA
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NORFLEET ANDREAM, CLARKE CHARLOTTEH, GAMETCHU BAHIRU, WATSON CHERYLS. Antibodies to the estrogen receptor-alpha modulate rapid prolactin release from rat pituitary tumor cells through plasma membrane estrogen receptors. FASEB J 2000; 14:157-65. [PMID: 10627290 PMCID: PMC1189731 DOI: 10.1096/fasebj.14.1.157] [Citation(s) in RCA: 93] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Antibodies (Abs) raised against the estrogen receptor-alpha (ERalpha) were used to investigate the role of ERalpha proteins located at the plasma membrane in mediating the rapid, estrogen-stimulated secretion of prolactin (PRL) from rat pituitary GH(3)/B6/F10 cells. Exposure of the cells to 1 nM 17beta-estradiol (E(2)) significantly increased PRL release after 3 or 6 min. When ERalpha Abs that bind specifically to ERalpha but are too large to diffuse into cells were tested for activity at the cell membrane, Ab R4, targeted to an ERalpha hinge region sequence, increased PRL release in a time- and concentration-dependent fashion. Ab H151, directed against a different hinge region epitope, decreased PRL release and blocked the stimulatory action of E(2). Abs raised against the DNA binding domain (H226) or the carboxyl terminus (C542) were not biologically active. When each Ab was examined for recognition of ERalpha on the cell surface by immunocytochemistry, all except H151 generated immunostaining in aldehyde-fixed cells. In live cells, however, Ab H151 but not Ab R4 blocked the membrane binding of fluorescently tagged E(2)-BSA. Overall, the data indicate that plasma membrane ERalpha proteins mediate estrogen-stimulated PRL release from GH(3)/B6/F10 cells. These results may also convey information about conformationally sensitive areas of the membrane form of ERalpha involved in rapid, nongenomic responses to estrogens.
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Affiliation(s)
| | - CHARLOTTE H. CLARKE
- Department of Pharmacology, University of Texas Medical Branch, Galveston, TX 77555, USA; and
| | - BAHIRU GAMETCHU
- Department of Pediatrics, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - CHERYL S. WATSON
- Department of Human Biological Chemistry and Genetics, and
- Correspondence: Department of Human Biological Chemistry and Genetics, University of Texas Medical Branch, Galveston, TX 77555-0645, USA. E-mail:
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Watson CS, Campbell CH, Gametchu B. Membrane oestrogen receptors on rat pituitary tumour cells: immuno-identification and responses to oestradiol and xenoestrogens. Exp Physiol 1999; 84:1013-22. [PMID: 10564698 PMCID: PMC1931420 DOI: 10.1111/j.1469-445x.1999.01903.x] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Our laboratory has identified plasma membrane oestrogen receptors on a GH3/B6 rat pituitary tumour cell line and several sublines which produce rapid (within minutes), non-genomic responses to oestrogens. Oestrogen receptors have been identified by their binding to nine different antibodies (Abs) which together recognize at least seven epitopes on the oestrogen receptor-alpha. GH3/B6/F10 cells, a membrane oestrogen receptor-enriched subline, elevate intracellular calcium levels in response to 10 nM oestradiol. Prolactin release in these cells is triggered by both 1 pM and 1 nM oestradiol and diethylstilbestrol (DES). A membrane oestrogen receptor-alpha immunocytochemical signal rapidly disappears (at 3 min) and reappears (at 12-15 min) when 1 nM oestradiol, 10 nM diethylstilbestrol, or 10 nM nonylphenol is applied to the cells. This suggests that both oestrogens and xenoestrogens can utilize this alternative pathway for oestrogenic action. Xenoestrogens, which have so far shown weak effects in genomic assay systems, should now be retested for activity in eliciting membrane-initiated oestrogenic responses.
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Affiliation(s)
- C S Watson
- Human Biological Chemistry & Genetics Department, University of Texas Medical Branch, Galveston, TX 77555-0645, USA.
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Tanabe S, Hata T, Hiraoka M. Effects of estrogen on action potential and membrane currents in guinea pig ventricular myocytes. THE AMERICAN JOURNAL OF PHYSIOLOGY 1999; 277:H826-33. [PMID: 10444511 DOI: 10.1152/ajpheart.1999.277.2.h826] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
To explore a possible ionic basis for the prolonged Q-T interval in women compared with that in men, we investigated the electrophysiological effects of estrogen in isolated guinea pig ventricular myocytes. Action potentials and membrane currents were recorded using the whole cell configuration of the patch-clamp technique. Application of 17beta-estradiol (10-30 microM) significantly prolonged the action potential duration (APD) at 20% (APD(20)) and 90% repolarization (APD(90)) at stimulation rates of 0. 1-2.0 Hz. In the presence of 30 microM 17beta-estradiol, APD(20) and APD(90) at 0.1 Hz were prolonged by 46.2 +/- 17.1 and 63.4 +/- 11.7% of the control (n = 5), respectively. In the presence of 30 microM 17beta-estradiol the peak inward Ca(2+) current (I(CaL)) was decreased to 80.1 +/- 2.5% of the control (n = 4) without a shift in its voltage dependence. Application of 30 microM 17beta-estradiol decreased the rapidly activating component of the delayed outward K(+) current (I(Kr)) to 63.4 +/- 8% and the slowly activating component (I(Ks)) to 65.8 +/- 8.7% with respect to the control; the inward rectifier K(+) current was barely affected. The results suggest that 17beta-estradiol prolonged APD mainly by inhibiting the I(K) components I(Kr) and I(Ks).
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Affiliation(s)
- S Tanabe
- Department of Cardiovascular Diseases, Medical Research Institute, Tokyo Medical and Dental University, Tokyo 113-8510, Japan
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38
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Pickford DB, Morris ID. Effects of endocrine-disrupting contaminants on amphibian oogenesis: methoxychlor inhibits progesterone-induced maturation of Xenopus laevis oocytes in vitro. ENVIRONMENTAL HEALTH PERSPECTIVES 1999; 107:285-92. [PMID: 10090707 PMCID: PMC1566524 DOI: 10.1289/ehp.99107285] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
There is currently little evidence of pollution-induced endocrine dysfunction in amphibia, in spite of widespread concern over global declines in this ecologically diverse group. Data regarding the potential effects of endocrine-disrupting contaminants (EDCs) on reproductive function in amphibia are particularly lacking. We hypothesized that estrogenic EDCs may disrupt progesterone-induced oocyte maturation in the adult amphibian ovary, and tested this with an in vitro germinal vesicle breakdown assay using defolliculated oocytes from the African clawed frog, Xenopus laevis. While a variety of natural and synthetic estrogens and xenoestrogens were inactive in this system, the proestrogenic pesticide methoxychlor was a surprisingly potent inhibitor of progesterone-induced oocyte maturation (median inhibitive concentration, 72 nM). This inhibitory activity was specific to methoxychlor, rather than to its estrogenic contaminants or metabolites, and was not antagonized by the estrogen receptor antagonist ICI 182,780, suggesting that this activity is not estrogenic per se. The inhibitory activity of methoxychlor was dose dependent, reversible, and early acting. However, washout was unable to reverse the effect of short methoxychlor exposure, and methoxychlor did not competitively displace [3H]progesterone from a specific binding site in the oocyte plasma membrane. Therefore, methoxychlor may exert its action not directly at the site of progesterone action, but downstream on early events in maturational signaling, although the precise mechanism of action is unclear. The activity of methoxychlor in this system indicates that xenobiotics may exert endocrine-disrupting effects through interference with progestin-regulated processes and through mechanisms other than receptor antagonism.
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Affiliation(s)
- D B Pickford
- Division of Physiology, Pharmacology and Toxicology, School of Biological Sciences, University of Manchester, Manchester, UK
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Toran-Allerand CD, Singh M, Sétáló G. Novel mechanisms of estrogen action in the brain: new players in an old story. Front Neuroendocrinol 1999; 20:97-121. [PMID: 10328986 DOI: 10.1006/frne.1999.0177] [Citation(s) in RCA: 345] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Estrogen elicits a selective enhancement of the growth and differentiation of axons and dendrites (neurites) in the developing brain. Widespread colocalization of estrogen and neurotrophin receptors (trk) within estrogen and neurotrophin targets, including neurons of the cerebral cortex, sensory ganglia, and PC12 cells, has been shown to result in differential and reciprocal transcriptional regulation of these receptors by their ligands. In addition, estrogen and neurotrophin receptor coexpression leads to convergence or cross-coupling of their signaling pathways, particularly at the level of the mitogen-activated protein (MAP) kinase cascade. 17beta-Estradiol elicits rapid (within 5-15 min) and sustained (at least 2 h) tyrosine phosphorylation and activation of the MAP kinases, extracellular-signal regulated kinase (ERK)1, and ERK2, which is successfully inhibited by the MAP kinase/ERK kinase 1 inhibitor PD98059, but not by the estrogen receptor (ER) antagonist ICI 182,780 and also does not appear to result from estradiol-induced activation of trk. Furthermore, the ability of estradiol to phosphorylate ERK persists even in ER-alpha knockout mice, implicating other estrogen receptors such as ER-beta in these actions of estradiol. The existence of an estrogen receptor-containing, multimeric complex consisting of hsp90, src, and B-Raf also suggests a direct link between the estrogen receptor and the MAP kinase signaling cascade. Collectively, these novel findings, coupled with our growing understanding of additional signaling substrates utilized by estrogen, provide alternative mechanisms for estrogen action in the developing brain which could explain not only some of the very rapid effects of estrogen, but also the ability of estrogen and neurotrophins to regulate the same broad array of cytoskeletal and growth-associated genes involved in neurite growth and differentiation. This review expands the usually restrictive view of estrogen action in the brain beyond the confines of sexual differentiation and reproductive neuroendocrine function. It considers the much broader question of estrogen as a neural growth factor with important influences on the development, survival, plasticity, regeneration, and aging of the mammalian brain and supports the view that the estrogen receptor is not only a ligand-induced transcriptional enhancer but also a mediator of rapid, nongenomic events.
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Affiliation(s)
- C D Toran-Allerand
- Department of Anatomy and Cell Biology, Center for Neurobiology, Columbia University College of Physicians and Surgeons, New York, New York 10032, USA.
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40
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Picotto G, Vazquez G, Boland R. 17beta-oestradiol increases intracellular Ca2+ concentration in rat enterocytes. Potential role of phospholipase C-dependent store-operated Ca2+ influx. Biochem J 1999; 339 ( Pt 1):71-7. [PMID: 10085229 PMCID: PMC1220129] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
Abstract
The involvement of the phospholipase C (PLC) pathway in the non-genomic regulation of duodenal cell Ca2+ concentration by 17beta-oestradiol was investigated. The PLC inhibitors neomycin (0.5 mM) and U-73122 (2 microM) suppressed the stimulatory effect of 0.1 nM 17beta-oestradiol on the 45Ca2+ influx into enterocytes isolated from rat duodenum. The hormone (1 pM to 10 nM) increased the formation of 1,2-diacylglycerol in a biphasic pattern, characterized by an early peak at 45 s (+82%) and a later peak at 5 min (+46%). Both PLC inhibitors suppressed the first peak but were unable to block the 17beta-oestradiol effect at 5 min. 17beta-Oestradiol also increased the generation of inositol 1,4,5-trisphosphate within 15 s, with maximal stimulation at 30 s. 17beta-Oestradiol induced a rapid (30 s) and sustained (up to 5 min) increase in the intracellular Ca2+ concentration ([Ca2+]i) of fura 2-loaded enterocytes. The fast rise in [Ca2+]i was specific because other sex steroid hormones were without effect and could be blocked to a great extent by U-73122 (by 86% at 1 min). The effects of 17beta-oestradiol on enterocyte [Ca2+]i were decreased significantly (by 75%) in a Ca2+-free extracellular medium but a pronounced increase in [Ca2+]i was obtained after readmission of Ca2+ to the medium. The latter change was suppressed by 10 microM La3+, whereas nitrendipine (1 microM) and verapamil (10 microM) separately were without effect. The permeability of the 17beta-oestradiol-induced Ca2+ influx pathway to Mn2+ was increased 2.8-fold by treatment with oestrogen. These results suggest the operation of a PLC-dependent store-operated Ca2+ channel mechanism in 17beta-oestradiol regulation of enterocyte extracellular Ca2+ influx.
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Affiliation(s)
- G Picotto
- Departamento de Biolog approximately ía, Bioqu approximately ímica y Farmacia, Universidad Nacional del Sur, San Juan 670, 8000 Bahia Blanca, Argentina
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Abstract
Estrogens exert fast non-genomic actions in their target tissues which may involve the participation of receptors located at the cell membrane. Studies were performed to identify and characterize membrane-associated 17beta-estradiol binding proteins in rabbit uterus. Specific and saturable [3H]17beta-estradiol binding sites of high affinity (Kd = 0.36 nM) were detected in uterine microsomes at higher concentration than in cytosol (370 +/- 98 vs. 270 +/- 87 fmol/mg protein, respectively). Various other steroid hormones, the stereoisomer 17alpha-estradiol and the antiestrogen tamoxifen were significantly less effective than 17beta-estradiol to compete with the radioactive ligand for binding to the membranes. The microsome binding sites were trypsin-sensitive and could be extracted to a great extent (80-90%) with 0.4/0.6 M KCl. Assays of the marker enzyme glucose-6-P dehydrogenase excluded membrane contamination with cytosolic soluble components. Immunoblot analysis of particulate and soluble fractions using monoclonal antibodies against the transactivation, heat shock protein recognition, and steroid binding domains of the nuclear estrogen receptor (ER; 67 kDa), revealed lower concentrations of the ER in membranes and the presence of five additional immunoreactive proteins of 57, 50, 32, 28, and 11 kDa which were absent in cytosol. Moreover, the antibody against the steroid binding domain was as effective as an inhibitor for cytosolic and membrane specific radioligand binding. Extraction of microsomes with the nondenaturing detergent CHAPS allowed a 2-fold enrichment of ER-like binding proteins as shown by antibody labeling and [3H]17beta-estradiol binding analysis. The results of this work are consistent with the existence of novel 17beta-estradiol membrane binding proteins structurally related to the intracellular ER. Future studies should investigate whether any of these proteins are involved in the primary events (e.g. receptor function) mediating nongenomic estrogen effects.
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Affiliation(s)
- P Monje
- Departamento de Biología, Bioquímica y Farmacia, Universidad Nacional del Sur, Bahia Blanca, Argentina
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Abstract
Practically all plant foods contain small amounts of the diverse phytoestrogen molecules that have the potential to improve health. Phytoestrogens, especially the soy-derived isoflavones, are receiving great scrutiny as food supplements for the purposes of both enhancing the health of tissues and preventing several common diseases, such as cardiovascular diseases, cancers of reproductive tissues and osteoporosis. Investigations of isoflavones, in particular, have recently become more prominent because of their oestrogenic activities. These actions may be as either partial oestrogen agonists or anti-oestrogens (inhibitors of natural oestrogen activity). For example, the isoflavones of soy, mainly genistein and daidzein, have been shown by at least three different laboratories to conserve bone in ovariectomized rodent models, and they probably have similar conservatory effects in higher mammalian species. Nevertheless, the only positive effects of phytoestrogens on bone observed so far in post-menopausal women have been small and limited to the lumbar vertebrae. Additional information on human studies currently in progress is needed before the efficacy of these preparations in human subjects is known.
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Affiliation(s)
- J J Anderson
- Department of Nutrition, Schools of Public Health and Medicine, University of North Carolina, Chapel Hill, USA
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Durkee TJ, Mueller M, Zinaman M. Identification of estrogen receptor protein and messenger ribonucleic acid in human spermatozoa. Am J Obstet Gynecol 1998; 178:1288-97. [PMID: 9662314 DOI: 10.1016/s0002-9378(98)70335-7] [Citation(s) in RCA: 69] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
OBJECTIVE The processes leading to fertilization involve a series of sequential events including the deposition and transport of sperm in the female genital tract. It is becoming evident that spermatozoa in which a hyperactive state has been induced are more effective in both reaching and penetrating the oocyte. Many of the changes that spermatozoa undergo are the result of their ability to respond to the milieu of the female genital tract. In the presence of estrogen sperm have been shown to have increased their metabolic activity and flagellar activity and to have an increased ability to penetrate oocytes. Most important, these observed changes in sperm physiology occur quickly, suggesting a novel second-messenger system coupled to the estrogen receptor. Established effects of steroid hormones involve mediation of the signal through genomic expression. However, because it has not been definitively demonstrated whether the human sperm express the estrogen receptor, the mechanism by which estrogen exert its effect remains to be elucidated. STUDY DESIGN The presence of estrogen receptors on human spermatozoa was investigated. Immunohistochemistry performed on human spermatozoa indicates that the estrogen receptors are located on the tailpiece. In addition, protein from human spermatozoa was isolated and subjected to Western blot analysis. RESULTS Results indicate a single band of approximately 65 kd, similar to that of the native human estrogen receptor. Ribonucleic acid obtained from the human spermatozoa was reverse transcribed into deoxyribonucleic acid. With use of selected primers, this deoxyribonucleic acid was amplified by polymerase chain reaction. Resolution and examination of the expansion products demonstrated a single band of deoxyribonucleic acid of 450 bp, identical to that expected from the selected primers. The specificity of this reverse transcriptase-polymerase chain reaction amplified deoxyribonucleic acid sequence was verified by Southern blotting. CONCLUSION For the first time we provide evidence as to the expression of estrogen receptor by human spermatozoa.
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Affiliation(s)
- T J Durkee
- Department of Obstetrics and Gynecology, Rockford Clinic, Illinois, USA
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Rao BR. Isolation and characterization of an estrogen binding protein which may integrate the plethora of estrogenic actions in non-reproductive organs. J Steroid Biochem Mol Biol 1998; 65:3-41. [PMID: 9699855 DOI: 10.1016/s0960-0760(98)00019-3] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A putative estrogen receptor (pER) from mouse liver has been characterized. The heterodimer protein (81-84 kDa) consists of two covalently bound subunits (61-67 and 17-27 kDa) with following characteristics: sedimentation constant--4.9 S; IP--4.8; dissociation constant (Kd) for estradiol-17beta binding--0.7 nmol; binding sites--0.746 pmol/mg protein; relative binding affinity--estradiol-17beta--100, estrone--80 and estriol--30; specificity--does not bind, other natural steroids, synthetic estrogens, antiestrogens and bioflavonoids. Importantly, immunosuppressants, neuroleptic and carcinogens influence 3H-estradiol-17beta binding to pER. Interestingly, pER is a serine phosphatase and this may have relevancy to estrogen action in Alzheimer's disease. The polyclonal anti-pER antibody does not react with estrogen receptors (ER). ER antibody does not react with pER. Remarkably, anti-pER antibody reacts with calcineurin, a brain phosphatase and anti-calcineurin antibody reacts with pER. Immunohistochemical analyses showed that pER is undetectable in reproductive organs (except ovary). It is localized on the plasma or the nuclear membranes in some, in cytoplasm and/or nucleus in other cells of non-reproductive organs (skeletal, neural, vascular, hair and retina), and in tumors (mammary, endometrial and prostate cancers, and prostatic hyperplasia). The information presented justifies the proposition that pER may mediate the estrogenic actions in non-reproductive organs.
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MESH Headings
- 9,10-Dimethyl-1,2-benzanthracene/pharmacology
- Animals
- Antibody Specificity
- Antipsychotic Agents/metabolism
- Binding, Competitive
- Calmodulin/metabolism
- Chickens
- Estradiol/metabolism
- Estriol/metabolism
- Estrogens/metabolism
- Estrone/metabolism
- Female
- Genitalia, Female/chemistry
- Genitalia, Female/ultrastructure
- Humans
- Immunosuppressive Agents/metabolism
- Liver/metabolism
- Liver/ultrastructure
- Male
- Mice
- Phosphoric Monoester Hydrolases/metabolism
- Prostate/chemistry
- Prostate/ultrastructure
- Rats
- Receptors, Estrogen/drug effects
- Receptors, Estrogen/immunology
- Receptors, Estrogen/isolation & purification
- Receptors, Estrogen/metabolism
- Sulfhydryl Reagents/pharmacology
- Tissue Distribution
- Tumor Cells, Cultured
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Affiliation(s)
- B R Rao
- Brug 254, AZVU, Amsterdam, The Netherlands.
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45
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Zacharewski T. Identification and assessment of endocrine disruptors: limitations of in vivo and in vitro assays. ENVIRONMENTAL HEALTH PERSPECTIVES 1998; 106 Suppl 2:577-82. [PMID: 9599705 PMCID: PMC1533380 DOI: 10.1289/ehp.98106577] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
It has been suggested that chemicals and complex mixtures capable of modulating the endocrine system may contribute to adverse health, reproduction, and developmental effects in humans and wildlife. These effects include increased incidence of hormone-dependent cancers, compromised reproductive fitness, and abnormal reproductive system development. In response to public concern, regulatory agencies in North America and Europe are formulating potential strategies to systematically test chemicals and complex mixtures for their endocrine-disrupting activities. Because of the complexity of the endocrine system and the number of potential endocrine disruptor targets, a tiered approach involving a complementary battery of short- and long-term in vivo and in vitro assays that assesses both receptor and nonreceptor-mediated mechanisms of action is being considered. However, the available established assays use a limited number of end points, and significant information gaps exist for other potential targets in the endocrine system. In addition to discussing the merits and limitations of the assays that may be adopted, this paper also highlights potential problems associated with the use of a tiered testing strategy.
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Affiliation(s)
- T Zacharewski
- Department of Pharmacology and Toxicology, University of Western Ontario, London, Canada.
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46
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Rudel R. Predicting health effects of exposures to compounds with estrogenic activity: methodological issues. ENVIRONMENTAL HEALTH PERSPECTIVES 1997; 105 Suppl 3:655-663. [PMID: 9168010 PMCID: PMC1469898 DOI: 10.1289/ehp.97105s3655] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Many substances are active in in vitro tests for estrogenic activity, but data from multigenerational and other toxicity studies are not available for many of those substances. Controversy has arisen, therefore, concerning the likelihood of adverse health effects. Based on a toxic equivalence factor risk assessment approach, some researchers have concluded that exposure to environmental estrogens is not associated with estrogen receptor (ER)-mediated health effects. Their rationale cites the low potency of these compounds in in vitro assays relative to estradiol, and the widespread exposure to pharmaceutical, endogenous, and dietary estrogens. This reasoning relies on two assumptions: that the relative estrogenic potency in in vitro assays is predictive of the relative potency for the most sensitive in vivo estrogenic effect; and that all estrogens act via the same mechanism to produce the most sensitive in vivo estrogenic effect. Experimental data reviewed here suggest that these assumptions may be inappropriate because diversity in both mechanism and effect exists for estrogenic compounds. Examples include variations in ER-ligand binding to estrogen response elements, time course of nuclear ER accumulation, patterns of gene activation, and other mechanistic characteristics that are not reflected in many in vitro assays, but may have significance for ER-mediated in vivo effects. In light of these data, this report identifies emerging methodological issues in risk assessment for estrogenic compounds: the need to address differences in in vivo end points of concern and the associated mechanisms; pharmacokinetics; the crucial role of timing and duration of exposure; interactions; and non-ER-mediated activities of estrogenic compounds.
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Affiliation(s)
- R Rudel
- Silent Spring Institute, Newton, Massachusetts 02158, USA.
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