GPR30: a seven-transmembrane-spanning estrogen receptor that triggers EGF release.

PubMed

Filardo, Edward J; Thomas, Peter

2005-10-01

Heterotrimeric G proteins and seven-transmembrane-spanning (7TM) receptors are implicated in rapid estrogen signaling. The orphan 7TM receptor GPR30 is linked to estrogen-mediated activation of adenylyl cyclase, release of epidermal growth factor (EGF)-related ligands, and specific estrogen binding. GPR30 acts independently of estrogen receptors, ERalpha and ERbeta, and probably functions as a heptahelical ER. 7TM receptors elicit signals that stimulate second messengers, and convey intracellular signals via EGF receptors. Identification of GPR30 as a Gs-coupled 7TM receptor that triggers release of heparin-binding EGF establishes its role in cell signaling cascades initiated by estrogens, and explains their capacity to activate second messengers and promote EGF-like effects. Thus, estrogen can signal by the same mechanism as various other hormones, through a specific 7TM receptor.

The Estrogen Receptors: An Overview from Different Perspectives.

PubMed

Eyster, Kathleen M

2016-01-01

The estrogen receptors, ERα, ERβ, and GPER, mediate the effects of estrogenic compounds on their target tissues. Estrogen receptors are located in the tissues of the female reproductive tract and breast as one would expect, but also in tissues as diverse as bone, brain, liver, colon, skin, and salivary gland. The purpose of this discussion of the estrogen receptors is to provide a brief overview of the estrogen receptors and estrogen action from perspectives such as the historical, physiological, pharmacological, pathological, structural, and ligand perspectives.

Association of the membrane estrogen receptor, GPR30, with breast tumor metastasis and transactivation of the epidermal growth factor receptor.

PubMed

Filardo, Edward J; Quinn, Jeffrey A; Sabo, Edmond

2008-10-01

The epidermal growth factor receptor (EGFR) family of receptor tyrosine kinases function as a common signaling conduit for membrane receptors that lack intrinsic enzymatic activity, such as G-protein coupled receptors and integrins. GPR30, an orphan member of the seven transmembrane receptor (7TMR) superfamily has been linked to specific estrogen binding, rapid estrogen-mediated activation of adenylyl cyclase and the release of membrane-tethered proHB-EGF. More recently, GPR30 expression in primary breast adenocarcinoma has been associated with pathological parameters commonly used to assess breast cancer progression, including the development of extramammary metastases. This newly appreciated mechanism of cross communication between estrogen and EGF is consistent with the observation that 7TMR-mediated transactivation of the EGFR is a recurrent signaling paradigm and may explain prior data reporting the EGF-like effects of estrogen. The molecular details surrounding GPR30-mediated release of proHB-EGF, the involvement of integrin beta1 as a signaling intermediary in estrogen-dependent EGFR action, and the possible implications of these data for breast cancer progression are discussed herein.

Binding of Estrogenic Compounds to Recombinant Estrogen Receptor-α: Application to Environmental Analysis

PubMed Central

Pillon, Arnaud; Boussioux, Anne-Marie; Escande, Aurélie; Aït-Aïssa, Sélim; Gomez, Elena; Fenet, Hélène; Ruff, Marc; Moras, Dino; Vignon, Françoise; Duchesne, Marie-Josèphe; Casellas, Claude; Nicolas, Jean-Claude; Balaguer, Patrick

2005-01-01

Estrogenic activity in environmental samples could be mediated through a wide variety of compounds and by various mechanisms. High-affinity compounds for estrogen receptors (ERs), such as natural or synthetic estrogens, as well as low-affinity compounds such as alkylphenols, phthalates, and polychlorinated biphenyls are present in water and sediment samples. Furthermore, compounds such as polycyclic aromatic hydrocarbons, which do not bind ERs, modulate estrogen activity by means of the aryl hydrocarbon receptor (AhR). In order to characterize compounds that mediate estrogenic activity in river water and sediment samples, we developed a tool based on the ER-αligand-binding domain, which permitted us to estimate contaminating estrogenic compound affinities. We designed a simple transactivation assay in which compounds of high affinity were captured by limited amounts of recombinant ER-αand whose capture led to a selective inhibition of transactivation. This approach allowed us to bring to light that water samples contain estrogenic compounds that display a high affinity for ERs but are present at low concentrations. In sediment samples, on the contrary, we showed that estrogenic compounds possess a low affinity and are present at high concentration. Finally, we used immobilized recombinant ER-αto separate ligands for ER and AhR that are present in river sediments. Immobilized ER-α, which does not retain dioxin-like compounds, enabled us to isolate and concentrate ER ligands to facilitate their further analysis. PMID:15743715

GPER Mediates Non-Genomic Effects of Estrogen.

PubMed

Pupo, Marco; Maggiolini, Marcello; Musti, Anna Maria

2016-01-01

Estrogens are important modulators of a broad spectrum of physiological functions in humans. However, despite their beneficial actions, a number of lines of evidence correlate the sustained exposure to exogenous estrogen with increased risk of the onset of various cancers. Mainly these steroid hormones induce their effects by binding and activating estrogen receptors (ERα and ERβ). These receptors belong to the family of ligand-regulated transcription factors, and upon activation they regulate the expression of different target genes by binding directly to specific DNA sequences. On the other hand, in recent years it has become clear that the G protein-coupled estrogen receptor 30 (GPR30/GPER) is able to mediate non-genomic action of estrogens in different cell contexts. In particular, GPER has been shown to specifically bind estrogens, and in turn to functionally cross-react with diverse cell signaling systems such as the epidermal growth factor receptor (EGFR) pathway, the Notch signaling pathway and the mitogen-activated protein kinases (MAPK) pathway. In this chapter we will present some of the different experimental techniques currently used to demonstrate the functional role of GPER in mediating non-genomic actions of estrogens, such as the dual luciferase assay, assessment of the involvement of GPER in the stimulation of cell migration in breast cancer cell lines and in cancer-associated fibroblasts, and chromatin immunoprecipitation assay. Overall, the experimental procedures described herein represent key instruments for assessing the biological role of GPER in mediating non-genomic signals of estrogen.

G protein-coupled estrogen receptor inhibits the P2Y receptor-mediated Ca(2+) signaling pathway in human airway epithelia.

PubMed

Hao, Yuan; Chow, Alison W; Yip, Wallace C; Li, Chi H; Wan, Tai F; Tong, Benjamin C; Cheung, King H; Chan, Wood Y; Chen, Yangchao; Cheng, Christopher H; Ko, Wing H

2016-08-01

P2Y receptor activation causes the release of inflammatory cytokines in the bronchial epithelium, whereas G protein-coupled estrogen receptor (GPER), a novel estrogen (E2) receptor, may play an anti-inflammatory role in this process. We investigated the cellular mechanisms underlying the inhibitory effect of GPER activation on the P2Y receptor-mediated Ca(2+) signaling pathway and cytokine production in airway epithelia. Expression of GPER in primary human bronchial epithelial (HBE) or 16HBE14o- cells was confirmed on both the mRNA and protein levels. Stimulation of HBE or 16HBE14o- cells with E2 or G1, a specific agonist of GPER, attenuated the nucleotide-evoked increases in [Ca(2+)]i, whereas this effect was reversed by G15, a GPER-specific antagonist. G1 inhibited the secretion of two proinflammatory cytokines, interleukin (IL)-6 and IL-8, in cells stimulated by adenosine 5'-(γ-thio)triphosphate (ATPγS). G1 stimulated a real-time increase in cAMP levels in 16HBE14o- cells, which could be inhibited by adenylyl cyclase inhibitors. The inhibitory effects of E2 or G1 on P2Y receptor-induced increases in Ca(2+) were reversed by treating the cells with a protein kinase A (PKA) inhibitor. These results demonstrated that the inhibitory effects of G1 or E2 on P2Y receptor-mediated Ca(2+) mobilization and cytokine secretion were due to GPER-mediated activation of a cAMP-dependent PKA pathway. This study has reported, for the first time, the expression and function of GPER as an anti-inflammatory component in human bronchial epithelia, which may mediate through its opposing effects on the pro-inflammatory pathway activated by the P2Y receptors in inflamed airway epithelia.

Extent of Vascular Remodeling Is Dependent on the Balance Between Estrogen Receptor α and G-Protein-Coupled Estrogen Receptor.

PubMed

Gros, Robert; Hussain, Yasin; Chorazyczewski, Jozef; Pickering, J Geoffrey; Ding, Qingming; Feldman, Ross D

2016-11-01

Estrogens are important regulators of cardiovascular function. Some of estrogen's cardiovascular effects are mediated by a G-protein-coupled receptor mechanism, namely, G-protein-coupled estrogen receptor (GPER). Estradiol-mediated regulation of vascular cell programmed cell death reflects the balance of the opposing actions of GPER versus estrogen receptor α (ERα). However, the significance of these opposing actions on the regulation of vascular smooth muscle cell proliferation or migration in vitro is unclear, and the significance in vivo is unknown. To determine the effects of GPER activation in vitro, we studied rat aortic vascular smooth muscle cells maintained in primary culture. GPER was reintroduced using adenoviral gene transfer. Both estradiol and G1, a GPER agonist, inhibited both proliferation and cell migration effects that were blocked by the GPER antagonist, G15. To determine the importance of the GPER-ERα balance in regulating vascular remodeling in a rat model of carotid ligation, we studied the effects of upregulation of GPER expression versus downregulation of ERα. Reintroduction of GPER significantly attenuated the extent of medial hypertrophy and attenuated the extent of CD45 labeling. Downregulation of ERα expression comparably attenuated the extent of medial hypertrophy and inflammation after carotid ligation. These studies demonstrate that the balance between GPER and ERα regulates vascular remodeling. Receptor-specific modulation of estrogen's effects may be an important new approach in modifying vascular remodeling in both acute settings like vascular injury and perhaps in longer term regulation like in hypertension. © 2016 American Heart Association, Inc.

17β-Estradiol and Agonism of G-protein-Coupled Estrogen Receptor Enhance Hippocampal Memory via Different Cell-Signaling Mechanisms

PubMed Central

Kim, Jaekyoon; Szinte, Julia S.; Boulware, Marissa I.

2016-01-01

The ability of 17β-estradiol (E2) to enhance hippocampal object recognition and spatial memory depends on rapid activation of extracellular signal-regulated kinase (ERK) in the dorsal hippocampus (DH). Although this activation can be mediated by the intracellular estrogen receptors ERα and ERβ, little is known about the role that the membrane estrogen receptor GPER plays in regulating ERK or E2-mediated memory formation. In this study, post-training DH infusion of the GPER agonist G-1 enhanced object recognition and spatial memory in ovariectomized female mice, whereas the GPER antagonist G-15 impaired memory, suggesting that GPER activation, like E2, promotes hippocampal memory formation. However, unlike E2, G-1 did not increase ERK phosphorylation, but instead significantly increased phosphorylation of c-Jun N-terminal kinase (JNK) in the DH. Moreover, DH infusion of the JNK inhibitor SP600125 prevented G-1 from enhancing object recognition and spatial memory, but the ERK inhibitor U0126 did not. These data suggest that GPER enhances memory via different cell-signaling mechanisms than E2. This conclusion was supported by data showing that the ability of E2 to facilitate memory and activate ERK signaling was not blocked by G-15 or SP600125, which demonstrates that the memory-enhancing effects of E2 are not dependent on JNK or GPER activation in the DH. Together, these data indicate that GPER regulates memory independently from ERα and ERβ by activating JNK signaling, rather than ERK signaling. Thus, the findings suggest that GPER in the DH may not function as an estrogen receptor to regulate object recognition and spatial memory. SIGNIFICANCE STATEMENT Although 17β-estradiol has long been known to regulate memory function, the molecular mechanisms underlying estrogenic memory modulation remain largely unknown. Here, we examined whether the putative membrane estrogen receptor GPER acts like the classical estrogen receptors, ERα and ERβ, to facilitate

Tamoxifen regulation of bone growth and endocrine function in the ovariectomized rat: discrimination of responses involving estrogen receptor α/estrogen receptor β, G protein-coupled estrogen receptor, or estrogen-related receptor γ using fulvestrant (ICI 182780).

PubMed

Fitts, James M; Klein, Robert M; Powers, C Andrew

2011-07-01

Tamoxifen is a selective estrogen receptor (ER) modulator, but it is also a deactivating ligand for estrogen-related receptor-γ (ERRγ) and a full agonist for the G protein-coupled estrogen receptor (GPER). Fulvestrant is a selective ER down-regulator that lacks agonist effects on ERα/ERβ, is inactive on ERRγ, but acts as a full agonist on GPER. Fulvestrant effects on tamoxifen actions on uterine and somatic growth, bone, the growth hormone (GH)-insulin-like growth factor I (IGF-I) axis, and pituitary prolactin were analyzed to pharmacologically discriminate tamoxifen effects that may be mediated by ERα/ERβ versus ERRγ versus GPER. Ovariectomized rats received tamoxifen (0.6 mg/kg/daily) plus fulvestrant at 0, 3, 6, or 12 mg/kg/daily for 5 weeks; controls received vehicle or 6 mg/kg fulvestrant daily. Tamoxifen effects to increase uterine weight, decrease serum IGF-I, increase pituitary prolactin, and increase bone mineral density could be fully blocked by fulvestrant, indicating mediation by ERα/ERβ. Tamoxifen effects to decrease pituitary GH, tibia length, and body weight were only partially blocked by fulvestrant, indicating involvement of mechanisms unrelated to ERα/ERβ. Fulvestrant did not inhibit tamoxifen actions to reduce total pituitary protein, again indicating effects not mediated by ERα/ERβ. Tamoxifen actions to reduce serum GH were mimicked rather than inhibited by fulvestrant, pharmacological features consistent with GPER involvement. However, fulvestrant alone increased IGF-I and also blocked tamoxifen-evoked IGF-I decreases; thus fulvestrant effects on serum GH might reflect increased IGF-I feedback inhibition. Fulvestrant alone had no effect on the other parameters. The findings indicate that mechanisms unrelated to ERα/ERβ contribute to tamoxifen effects on body weight, bone growth, and pituitary function.

Endoxifen, 4-Hydroxytamoxifen and an Estrogenic Derivative Modulate Estrogen Receptor Complex Mediated Apoptosis in Breast Cancer.

PubMed

Maximov, Philipp Y; Abderrahman, Balkees; Fanning, Sean W; Sengupta, Surojeet; Fan, Ping; Curpan, Ramona F; Quintana Rincon, Daniela Maria; Greenland, Jeffery A; Rajan, Shyamala S; Greene, Geoffrey L; Jordan, V Craig

2018-05-08

Estrogen therapy was used to treat advanced breast cancer in postmenopausal women for decades until the introduction of tamoxifen. Resistance to long-term estrogen deprivation (LTED) with tamoxifen and aromatase inhibitors used as a treatment for breast cancer inevitably occurs, but unexpectedly low dose estrogen can cause regression of breast cancer and increase disease free survival in some patients. This therapeutic effect is attributed to estrogen-induced apoptosis in LTED breast cancer. Here we describe modulation of the estrogen receptor liganded with antiestrogens (endoxifen, 4-hydroxytamoxifen) and an estrogenic triphenylethylene (TPE) EthoxyTPE (EtOXTPE) on estrogen-induced apoptosis in LTED breast cancer cells. Our results show that the angular TPE estrogen (EtOXTPE) is able to induce the ER-mediated apoptosis only at a later time compared to planar estradiol in these cells. Using RT-PCR, ChIP, Western blotting, molecular modelling and X-ray crystallography techniques we report novel conformations of the ER complex with an angular estrogen EtOXTPE and endoxifen. We propose that alteration of the conformation of the ER complexes, with changes in coactivator binding, governs estrogen-induced apoptosis through the PERK sensor system to trigger an Unfolded Protein Response (UPR). The American Society for Pharmacology and Experimental Therapeutics.

Effects of atrazine on estrogen receptor α- and G protein-coupled receptor 30-mediated signaling and proliferation in cancer cells and cancer-associated fibroblasts.

PubMed

Albanito, Lidia; Lappano, Rosamaria; Madeo, Antonio; Chimento, Adele; Prossnitz, Eric R; Cappello, Anna Rita; Dolce, Vincenza; Abonante, Sergio; Pezzi, Vincenzo; Maggiolini, Marcello

2015-05-01

The pesticide atrazine does not bind to or activate the classical estrogen receptor (ER), but it up-regulates the aromatase activity in estrogen-sensitive tumor cells. The G protein estrogen receptor (GPR30/GPER) has been reported to be involved in certain biological responses to endogenous estrogens and environmental compounds exerting estrogen-like activity. We aimed to evaluate the potential of atrazine to trigger GPER-mediated signaling in cancer cells and cancer-associated fibroblasts (CAFs). Using gene reporter assays in diverse types of cancer cells, we found that atrazine did not transactivate endogenous ERα or chimeric proteins that encode the ERα and ERβ hormone binding domains. Conversely, atrazine was able to bind to GPER to induce ERK activation and the expression of estrogen target genes, which, interestingly, appeared to rely on both GPER and ERα expression. As a biological counterpart, atrazine stimulated the proliferation of ovarian cancer cells that depend on GPER and ERα, as evidenced by gene silencing experiments and the use of specific signaling inhibitors. Of note, through GPER, atrazine elicited ERK phosphorylation, gene expression, and migration in CAFs, thus extending its stimulatory role to these main players of the tumor microenvironment. Our results suggest a novel mechanism through which atrazine may exert relevant biological effects in cancer cells and CAFs. On the basis of our data, atrazine should be included among the environmental contaminants that may elicit estrogenic activity through GPER-mediated signaling.

Transcriptional targets shared by estrogen receptor- related receptors (ERRs) and estrogen receptor (ER) alpha, but not by ERbeta.

PubMed Central

Vanacker, J M; Pettersson, K; Gustafsson, J A; Laudet, V

1999-01-01

The physiological activities of estrogens are thought to be mediated by specific nuclear receptors, ERalpha and ERbeta. However, certain tissues, such as the bone, that are highly responsive to estrogens only express a low level of these receptors. Starting from this apparent contradiction, we have evaluated the potentials of two related receptors ERRalpha and ERRbeta to intervene in estrogen signaling. ERalpha, ERRalpha and ERRbeta bind to and activate transcription through both the classical estrogen response element (ERE) and the SF-1 response element (SFRE). In contrast, ERbeta DNA-binding and transcriptional activity is restricted to the ERE. Accordingly, the osteopontin gene promoter is stimulated through SFRE sequences, by ERRalpha as well as by ERalpha, but not by ERbeta. Analysis of the cross-talk within the ER/ERR subgroup of nuclear receptors thus revealed common targets but also functional differences between the two ERs. PMID:10428965

Estrogen enhances mismatch repair by induction of MLH1 expression via estrogen receptor-β

PubMed Central

Lu, Jun-Yu; Jin, Peng; Gao, Wei; Wang, De-Zhi; Sheng, Jian-Qiu

2017-01-01

Epidemiological data demonstrated that hormone replace treatment has protective effect against colorectal cancer (CRC). Our previous studies showed that this effect may be associated with DNA mismatch repair. This study aims to investigate the mechanism of estrogen induction of MLH1, and whether colorectal tumor proliferation can be inhibited through induction of MLH1 by estrogen signal pathway. Human CRC cell lines were used to examine the regulation of MLH1 expression by over-expression and depletion of estrogen receptor-α (ERα) and estrogen receptor-β (ERβ), under the treatment with 17β-estradiol or β-Estradiol 6-(O-carboxy-methyl)oxime:BSA, followed by a real-time Q-PCR and Western blotting analysis. Luciferase reporter and chromatin immunoprecipitation assays were used to identify the estrogen response elements in the proximal promoter of MLH1 gene. Then, the influence of estrogen-induced MLH1 on CRC tumor growth were determined in vitro and in vivo. We found that mismatch repair ability and microsatellite stability of cells were enhanced by estrogen via induction of MLH1 expression, which was mediated by ERβ, through a transcriptional activation process. Furthermore, we identified that ERβ exerted an inhibitory effect on CRC tumor proliferation in vitro and in vivo, combined with 5-FU, through up-regulation of MLH1 expression. Finally, we concluded that estrogen enhances mismatch repair ability and tumor inhibition effect in vitro and in vivo, via induction of MLH1 expression mediated by ERβ. PMID:28404976

Estrogen enhances mismatch repair by induction of MLH1 expression via estrogen receptor-β.

PubMed

Lu, Jun-Yu; Jin, Peng; Gao, Wei; Wang, De-Zhi; Sheng, Jian-Qiu

2017-06-13

Epidemiological data demonstrated that hormone replace treatment has protective effect against colorectal cancer (CRC). Our previous studies showed that this effect may be associated with DNA mismatch repair. This study aims to investigate the mechanism of estrogen induction of MLH1, and whether colorectal tumor proliferation can be inhibited through induction of MLH1 by estrogen signal pathway. Human CRC cell lines were used to examine the regulation of MLH1 expression by over-expression and depletion of estrogen receptor-α (ERα) and estrogen receptor-β (ERβ), under the treatment with 17β-estradiol or β-Estradiol 6-(O-carboxy-methyl)oxime:BSA, followed by a real-time Q-PCR and Western blotting analysis. Luciferase reporter and chromatin immunoprecipitation assays were used to identify the estrogen response elements in the proximal promoter of MLH1 gene. Then, the influence of estrogen-induced MLH1 on CRC tumor growth were determined in vitro and in vivo. We found that mismatch repair ability and microsatellite stability of cells were enhanced by estrogen via induction of MLH1 expression, which was mediated by ERβ, through a transcriptional activation process. Furthermore, we identified that ERβ exerted an inhibitory effect on CRC tumor proliferation in vitro and in vivo, combined with 5-FU, through up-regulation of MLH1 expression. Finally, we concluded that estrogen enhances mismatch repair ability and tumor inhibition effect in vitro and in vivo, via induction of MLH1 expression mediated by ERβ.

Involvement of epidermal growth factor receptor signaling in estrogen inhibition of oocyte maturation mediated through the G protein-coupled estrogen receptor (Gper) in zebrafish (Danio rerio).

PubMed

Peyton, Candace; Thomas, Peter

2011-07-01

Oocyte maturation (OM) in teleosts is under precise hormonal control by progestins and estrogens. We show here that estrogens activate an epidermal growth factor receptor (Egfr) signaling pathway in fully grown, denuded zebrafish (Danio rerio) oocytes through the G protein-coupled estrogen receptor (Gper; also known as GPR30) to maintain oocyte meiotic arrest in a germinal vesicle breakdown (GVBD) bioassay. A GPER-specific antagonist, G-15, increased spontaneous OM, indicating that the inhibitory estrogen actions on OM are mediated through Gper. Estradiol-17beta-bovine serum albumin, which cannot enter oocytes, decreased GVBD, whereas treatment with actinomycin D did not block estrogen's inhibitory effects, suggesting that estrogens act at the cell surface via a nongenomic mechanism to prevent OM. The intracellular tyrosine kinase (Src) inhibitor, PP2, blocked estrogen inhibition of OM. Expression of egfr mRNA and Egfr protein were detected in denuded zebrafish oocytes. The matrix metalloproteinase (MMP) inhibitor, ilomastat, which prevents the release of heparin-bound epidermal growth factor, increased spontaneous OM, whereas the MMP activator, interleukin-1alpha, decreased spontaneous OM. Moreover, inhibitors of EGFR (ErbB1) and extracellular-related kinase 1 and 2 (Erk1/2; official symbol Mapk3/1) increased spontaneous OM. In addition, estradiol-17beta and the GPER agonist, G-1, increased phosphorylation of Erk, and this was abrogated by simultaneous treatment with the EGFR inhibitor. Taken together, these results suggest that estrogens act through Gper to maintain meiotic arrest via an Src kinase-dependent G-protein betagamma subunit signaling pathway involving transactivation of egfr and phosphorylation of Mapk3/1. To our knowledge, this is the first evidence that EGFR signaling in vertebrate oocytes can prevent meiotic progression.

G Protein-Coupled Estrogen Receptor-Selective Ligands Modulate Endometrial Tumor Growth

PubMed Central

Petrie, Whitney K.; Dennis, Megan K.; Dai, Donghai; Arterburn, Jeffrey B.; Smith, Harriet O.; Hathaway, Helen J.; Prossnitz, Eric R.

2013-01-01

Endometrial carcinoma is the most common cancer of the female reproductive tract. GPER/GPR30 is a 7-transmembrane spanning G protein-coupled receptor that has been identified as the third estrogen receptor, in addition to ERα and ERβ. High GPER expression is predictive of poor survival in endometrial and ovarian cancer, but despite this, the estrogen-mediated signaling pathways and specific estrogen receptors involved in endometrial cancer remain unclear. Here, employing ERα-negative Hec50 endometrial cancer cells, we demonstrate that GPER mediates estrogen-stimulated activation of ERK and PI3K via matrix metalloproteinase activation and subsequent transactivation of the EGFR and that ER-targeted therapeutic agents (4-hydroxytamoxifen, ICI182,780/fulvestrant, and Raloxifene), the phytoestrogen genistein, and the “ERα-selective” agonist propylpyrazole triol also function as GPER agonists. Furthermore, xenograft tumors of Hec50 cells yield enhanced growth with G-1 and estrogen, the latter being inhibited by GPER-selective pharmacologic antagonism with G36. These results have important implications with respect to the use of putatively ER-selective ligands and particularly for the widespread long-term use of “ER-targeted” therapeutics. Moreover, our findings shed light on the potential mechanisms of SERM/SERD side effects reported in many clinical studies. Finally, our results provide the first demonstration that pharmacological inhibition of GPER activity in vivo prevents estrogen-mediated tumor growth. PMID:24379833

G protein-coupled estrogen receptor-selective ligands modulate endometrial tumor growth.

PubMed

Petrie, Whitney K; Dennis, Megan K; Hu, Chelin; Dai, Donghai; Arterburn, Jeffrey B; Smith, Harriet O; Hathaway, Helen J; Prossnitz, Eric R

2013-01-01

Endometrial carcinoma is the most common cancer of the female reproductive tract. GPER/GPR30 is a 7-transmembrane spanning G protein-coupled receptor that has been identified as the third estrogen receptor, in addition to ERα and ERβ. High GPER expression is predictive of poor survival in endometrial and ovarian cancer, but despite this, the estrogen-mediated signaling pathways and specific estrogen receptors involved in endometrial cancer remain unclear. Here, employing ERα-negative Hec50 endometrial cancer cells, we demonstrate that GPER mediates estrogen-stimulated activation of ERK and PI3K via matrix metalloproteinase activation and subsequent transactivation of the EGFR and that ER-targeted therapeutic agents (4-hydroxytamoxifen, ICI182,780/fulvestrant, and Raloxifene), the phytoestrogen genistein, and the "ERα-selective" agonist propylpyrazole triol also function as GPER agonists. Furthermore, xenograft tumors of Hec50 cells yield enhanced growth with G-1 and estrogen, the latter being inhibited by GPER-selective pharmacologic antagonism with G36. These results have important implications with respect to the use of putatively ER-selective ligands and particularly for the widespread long-term use of "ER-targeted" therapeutics. Moreover, our findings shed light on the potential mechanisms of SERM/SERD side effects reported in many clinical studies. Finally, our results provide the first demonstration that pharmacological inhibition of GPER activity in vivo prevents estrogen-mediated tumor growth.

Estrogen receptor signaling in prostate cancer: Implications for carcinogenesis and tumor progression.

PubMed

Bonkhoff, Helmut

2018-01-01

The androgen receptor (AR) is the classical target for prostate cancer prevention and treatment, but more recently estrogens and their receptors have also been implicated in prostate cancer development and tumor progression. Recent experimental and clinical data were reviewed to elucidate pathogenetic mechanisms how estrogens and their receptors may affect prostate carcinogenesis and tumor progression. The estrogen receptor beta (ERβ) is the most prevalent ER in the human prostate, while the estrogen receptor alpha (ERα) is restricted to basal cells of the prostatic epithelium and stromal cells. In high grade prostatic intraepithelial neoplasia (HGPIN), the ERα is up-regulated and most likely mediates carcinogenic effects of estradiol as demonstrated in animal models. The partial loss of the ERβ in HGPIN indicates that the ERβ acts as a tumor suppressor. The tumor promoting function of the TMPRSS2-ERG fusion, a major driver of prostate carcinogenesis, is triggered by the ERα and repressed by the ERβ. The ERβ is generally retained in hormone naïve and metastatic prostate cancer, but is partially lost in castration resistant disease. The progressive emergence of the ERα and ERα-regulated genes (eg, progesterone receptor (PR), PS2, TMPRSS2-ERG fusion, and NEAT1) during prostate cancer progression and hormone refractory disease suggests that these tumors can bypass the AR by using estrogens and progestins for their growth. In addition, nongenomic estrogen signaling pathways mediated by orphan receptors (eg, GPR30 and ERRα) has also been implicated in prostate cancer progression. Increasing evidences demonstrate that local estrogen signaling mechanisms are required for prostate carcinogenesis and tumor progression. Despite the recent progress in this research topic, the translation of the current information into potential therapeutic applications remains highly challenging and clearly warrants further investigation. © 2017 Wiley Periodicals, Inc.

17β-Estradiol and Agonism of G-protein-Coupled Estrogen Receptor Enhance Hippocampal Memory via Different Cell-Signaling Mechanisms.

PubMed

Kim, Jaekyoon; Szinte, Julia S; Boulware, Marissa I; Frick, Karyn M

2016-03-16

The ability of 17β-estradiol (E2) to enhance hippocampal object recognition and spatial memory depends on rapid activation of extracellular signal-regulated kinase (ERK) in the dorsal hippocampus (DH). Although this activation can be mediated by the intracellular estrogen receptors ERα and ERβ, little is known about the role that the membrane estrogen receptor GPER plays in regulating ERK or E2-mediated memory formation. In this study, post-training DH infusion of the GPER agonist G-1 enhanced object recognition and spatial memory in ovariectomized female mice, whereas the GPER antagonist G-15 impaired memory, suggesting that GPER activation, like E2, promotes hippocampal memory formation. However, unlike E2, G-1 did not increase ERK phosphorylation, but instead significantly increased phosphorylation of c-Jun N-terminal kinase (JNK) in the DH. Moreover, DH infusion of the JNK inhibitor SP600125 prevented G-1 from enhancing object recognition and spatial memory, but the ERK inhibitor U0126 did not. These data suggest that GPER enhances memory via different cell-signaling mechanisms than E2. This conclusion was supported by data showing that the ability of E2 to facilitate memory and activate ERK signaling was not blocked by G-15 or SP600125, which demonstrates that the memory-enhancing effects of E2 are not dependent on JNK or GPER activation in the DH. Together, these data indicate that GPER regulates memory independently from ERα and ERβ by activating JNK signaling, rather than ERK signaling. Thus, the findings suggest that GPER in the DH may not function as an estrogen receptor to regulate object recognition and spatial memory. Although 17β-estradiol has long been known to regulate memory function, the molecular mechanisms underlying estrogenic memory modulation remain largely unknown. Here, we examined whether the putative membrane estrogen receptor GPER acts like the classical estrogen receptors, ERα and ERβ, to facilitate hippocampal memory in female

Importance of Extranuclear Estrogen Receptor-α and Membrane G Protein–Coupled Estrogen Receptor in Pancreatic Islet Survival

PubMed Central

Liu, Suhuan; Le May, Cedric; Wong, Winifred P.S.; Ward, Robert D.; Clegg, Deborah J.; Marcelli, Marco; Korach, Kenneth S.; Mauvais-Jarvis, Franck

2009-01-01

OBJECTIVE We showed that 17β-estradiol (E2) favors pancreatic β-cell survival via the estrogen receptor-α (ERα) in mice. E2 activates nuclear estrogen receptors via an estrogen response element (ERE). E2 also activates nongenomic signals via an extranuclear form of ERα and the G protein–coupled estrogen receptor (GPER). We studied the contribution of estrogen receptors to islet survival. RESEARCH DESIGN AND METHODS We used mice and islets deficient in estrogen receptor-α (αERKO−/−), estrogen receptor-β (βERKO−/−), estrogen receptor-α and estrogen receptor-β (αβERKO−/−), and GPER (GPERKO−/−); a mouse lacking ERα binding to the ERE; and human islets. These mice and islets were studied in combination with receptor-specific pharmacological probes. RESULTS We show that ERα protection of islet survival is ERE independent and that E2 favors islet survival through extranuclear and membrane estrogen receptor signaling. We show that ERβ plays a minor cytoprotective role compared to ERα. Accordingly, βERKO−/− mice are mildly predisposed to streptozotocin-induced islet apoptosis. However, combined elimination of ERα and ERβ in mice does not synergize to provoke islet apoptosis. In αβERKO−/− mice and their islets, E2 partially prevents apoptosis suggesting that an alternative pathway compensates for ERα/ERβ deficiency. We find that E2 protection of islet survival is reproduced by a membrane-impermeant E2 formulation and a selective GPER agonist. Accordingly, GPERKO−/− mice are susceptible to streptozotocin-induced insulin deficiency. CONCLUSIONS E2 protects β-cell survival through ERα and ERβ via ERE-independent, extra-nuclear mechanisms, as well as GPER-dependent mechanisms. The present study adds a novel dimension to estrogen biology in β-cells and identifies GPER as a target to protect islet survival. PMID:19587358

Importance of extranuclear estrogen receptor-alpha and membrane G protein-coupled estrogen receptor in pancreatic islet survival.

PubMed

Liu, Suhuan; Le May, Cedric; Wong, Winifred P S; Ward, Robert D; Clegg, Deborah J; Marcelli, Marco; Korach, Kenneth S; Mauvais-Jarvis, Franck

2009-10-01

We showed that 17beta-estradiol (E(2)) favors pancreatic beta-cell survival via the estrogen receptor-alpha (ERalpha) in mice. E(2) activates nuclear estrogen receptors via an estrogen response element (ERE). E(2) also activates nongenomic signals via an extranuclear form of ERalpha and the G protein-coupled estrogen receptor (GPER). We studied the contribution of estrogen receptors to islet survival. We used mice and islets deficient in estrogen receptor-alpha (alphaERKO(-/-)), estrogen receptor-beta (betaERKO(-/-)), estrogen receptor-alpha and estrogen receptor-beta (alphabetaERKO(-/-)), and GPER (GPERKO(-/-)); a mouse lacking ERalpha binding to the ERE; and human islets. These mice and islets were studied in combination with receptor-specific pharmacological probes. We show that ERalpha protection of islet survival is ERE independent and that E(2) favors islet survival through extranuclear and membrane estrogen receptor signaling. We show that ERbeta plays a minor cytoprotective role compared to ERalpha. Accordingly, betaERKO(-/-) mice are mildly predisposed to streptozotocin-induced islet apoptosis. However, combined elimination of ERalpha and ERbeta in mice does not synergize to provoke islet apoptosis. In alphabetaERKO(-/-) mice and their islets, E(2) partially prevents apoptosis suggesting that an alternative pathway compensates for ERalpha/ERbeta deficiency. We find that E(2) protection of islet survival is reproduced by a membrane-impermeant E(2) formulation and a selective GPER agonist. Accordingly, GPERKO(-/-) mice are susceptible to streptozotocin-induced insulin deficiency. E(2) protects beta-cell survival through ERalpha and ERbeta via ERE-independent, extra-nuclear mechanisms, as well as GPER-dependent mechanisms. The present study adds a novel dimension to estrogen biology in beta-cells and identifies GPER as a target to protect islet survival.

The Estrogen Receptor-α in Osteoclasts Mediates the Protective Effects of Estrogens on Cancellous But Not Cortical Bone

PubMed Central

Martin-Millan, Marta; Almeida, Maria; Ambrogini, Elena; Han, Li; Zhao, Haibo; Weinstein, Robert S.; Jilka, Robert L.; O'Brien, Charles A.; Manolagas, Stavros C.

2010-01-01

Estrogens attenuate osteoclastogenesis and stimulate osteoclast apoptosis, but the molecular mechanism and contribution of these effects to the overall antiosteoporotic efficacy of estrogens remain controversial. We selectively deleted the estrogen receptor (ER)α from the monocyte/macrophage cell lineage in mice (ERαLysM−/−) and found a 2-fold increase in osteoclast progenitors in the marrow and the number of osteoclasts in cancellous bone, along with a decrease in cancellous bone mass. After loss of estrogens these mice failed to exhibit the expected increase in osteoclast progenitors, the number of osteoclasts in bone, and further loss of cancellous bone. However, they lost cortical bone indistinguishably from their littermate controls. Mature osteoclasts from ERαLysM−/− were resistant to the proapoptotic effect of 17β-estradiol. Nonetheless, the effects of estrogens on osteoclasts were unhindered in mice bearing an ERα knock-in mutation that prevented binding to DNA. Moreover, a polymeric form of estrogen that is not capable of stimulating the nuclear-initiated actions of ERα was as effective as 17β-estradiol in inducing osteoclast apoptosis in cells with the wild-type ERα. We conclude that estrogens attenuate osteoclast generation and life span via cell autonomous effects mediated by DNA-binding-independent actions of ERα. Elimination of these effects is sufficient for loss of bone in the cancellous compartment in which complete perforation of trabeculae by osteoclastic resorption precludes subsequent refilling of the cavities by the bone-forming osteoblasts. However, additional effects of estrogens on osteoblasts, osteocytes, and perhaps other cell types are required for their protective effects on the cortical compartment, which constitutes 80% of the skeleton. PMID:20053716

Involvement of Epidermal Growth Factor Receptor Signaling in Estrogen Inhibition of Oocyte Maturation Mediated Through the G Protein-Coupled Estrogen Receptor (Gper) in Zebrafish (Danio rerio)1

PubMed Central

Peyton, Candace; Thomas, Peter

2011-01-01

Oocyte maturation (OM) in teleosts is under precise hormonal control by progestins and estrogens. We show here that estrogens activate an epidermal growth factor receptor (Egfr) signaling pathway in fully grown, denuded zebrafish (Danio rerio) oocytes through the G protein-coupled estrogen receptor (Gper; also known as GPR30) to maintain oocyte meiotic arrest in a germinal vesicle breakdown (GVBD) bioassay. A GPER-specific antagonist, G-15, increased spontaneous OM, indicating that the inhibitory estrogen actions on OM are mediated through Gper. Estradiol-17beta-bovine serum albumin, which cannot enter oocytes, decreased GVBD, whereas treatment with actinomycin D did not block estrogen's inhibitory effects, suggesting that estrogens act at the cell surface via a nongenomic mechanism to prevent OM. The intracellular tyrosine kinase (Src) inhibitor, PP2, blocked estrogen inhibition of OM. Expression of egfr mRNA and Egfr protein were detected in denuded zebrafish oocytes. The matrix metalloproteinase (MMP) inhibitor, ilomastat, which prevents the release of heparin-bound epidermal growth factor, increased spontaneous OM, whereas the MMP activator, interleukin-1alpha, decreased spontaneous OM. Moreover, inhibitors of EGFR (ErbB1) and extracellular-related kinase 1 and 2 (Erk1/2; official symbol Mapk3/1) increased spontaneous OM. In addition, estradiol-17beta and the GPER agonist, G-1, increased phosphorylation of Erk, and this was abrogated by simultaneous treatment with the EGFR inhibitor. Taken together, these results suggest that estrogens act through Gper to maintain meiotic arrest via an Src kinase-dependent G-protein betagamma subunit signaling pathway involving transactivation of egfr and phosphorylation of Mapk3/1. To our knowledge, this is the first evidence that EGFR signaling in vertebrate oocytes can prevent meiotic progression. PMID:21349822

G protein-coupled estrogen receptor 1 (GPER 1) mediates estrogen-induced, proliferation of leiomyoma cells.

PubMed

Jiang, Xiuxiu; Ye, Xiaolei; Ma, Junyan; Li, Wen; Wu, Ruijin; Jun, Lin

2015-01-01

G protein-coupled estrogen receptor 1 (GPER-1, formerly known as GPR30) has been proposed as the receptor for estrogen-induced, growth of leiomyomas though its precise mechanisms of action are not clear. We obtained leiomyoma cells (LC) and normal smooth muscle cells from 28 women (n = 28, median age 38 years, median parity 1.0). We incubated them with 17-β estradiol (E(2)), after blocking, or upregulating, expression of GPER-1 with ICI182,780 (a GPER-1 agonist) and siGPR30, respectively. We evaluated the role of GPER-1 in the mitogen-activated protein kinase (MAPK) signaling pathway using Western blot analysis. We studied cell proliferation with 3-(4,5-dimethylthiazol-2-yl)2,5-diphenyl tetrazolium bromide, and, mitotic activity with phosphohistone H3 (PPH3) expression in leiomyoma, and, matched, normal, smooth muscle tissues using standard immunohistochemistry. Downregulation of GPER-1 expression with siGPR30 partially attenuated the E(2)-activated MAPK signaling pathway (p < 0.01). Upregulation of GPER-1 with ICI182,780 enhanced the E(2)-activated MAPK signaling pathway (p < 0.01). ICI182,780 enhanced E(2)-induced proliferation of LC (p < 0.01), while knock down of the GPER-1 gene with GPER-1 small interfering RNA partially inhibited E(2)-induced cell proliferation (p < 0.01). There were no significant differences in PPH3 expression between LCs and normal smooth muscle tissues (p > 0.05). Neither ICI182,780 nor siGPR30 increased mitosis in LCs (p > 0.05). Our results indicate that GPER-1 mediates proliferation of estrogen-induced, LC by activating the MAPK pathway, and, not by promoting mitosis.

Estrogen receptor α is required for oviductal transport of embryos

PubMed Central

Li, Shuai; O’Neill, Sofia R. S.; Zhang, Yong; Holtzman, Michael J.; Takemaru, Ken-Ichi; Korach, Kenneth S.; Winuthayanon, Wipawee

2017-01-01

Newly fertilized embryos spend the first few days within the oviduct and are transported to the uterus, where they implant onto the uterine wall. An implantation of the embryo before reaching the uterus could result in ectopic pregnancy and lead to maternal death. Estrogen is necessary for embryo transport in mammals; however, the mechanism involved in estrogen-mediated cellular function within the oviduct remains unclear. In this study, we show in mouse models that ciliary length and beat frequency of the oviductal epithelial cells are regulated through estrogen receptor α (ESR1) but not estrogen receptor β (ESR2). Gene profiling indicated that transcripts in the WNT/β-catenin (WNT/CTNNB1) signaling pathway were regulated by estrogen in mouse oviduct, and inhibition of this pathway in a whole oviduct culture system resulted in a decreased embryo transport distance. However, selective ablation of CTNNB1 from the oviductal ciliated cells did not affect embryo transport, possibly because of a compensatory mechanism via intact CTNNB1 in the adjacent secretory cells. In summary, we demonstrated that disruption of estrogen signaling in oviductal epithelial cells alters ciliary function and impairs embryo transport. Therefore, our findings may provide a better understanding of etiology of the ectopic pregnancy that is associated with alteration of estrogen signals.—Li, S., O’Neill, S. R. S., Zhang, Y., Holtzman, M. J., Takemaru, K.-I., Korach, K. S., Winuthayanon, W. Estrogen receptor α is required for oviductal transport of embryos. PMID:28082352

GPR30 mediates anorectic estrogen-induced STAT3 signaling in the hypothalamus.

PubMed

Kwon, Obin; Kang, Eun Seok; Kim, Insook; Shin, Sora; Kim, Mijung; Kwon, Somin; Oh, So Ra; Ahn, Young Soo; Kim, Chul Hoon

2014-11-01

Estrogen plays an important role in the control of energy balance in the hypothalamus. Leptin-independent STAT3 activation (i.e., tyrosine(705)-phosphorylation of STAT3, pSTAT3) in the hypothalamus is hypothesized as the primary mechanism of the estrogen-induced anorexic response. However, the type of estrogen receptor that mediates this regulation is unknown. We investigated the role of the G protein-coupled receptor 30 (GPR30) in estradiol (E2)-induced STAT3 activation in the hypothalamus. Regulation of STAT3 activation by E2, G-1, a specific agonist of GPR30 and G-15, a specific antagonist of GPR30 was analyzed in vitro and in vivo. Effect of GPR30 activation on eating behavior was analyzed in vivo. E2 stimulated pSTAT3 in cells expressing GPR30, but not expressing estrogen receptor ERα and ERβ. G-1 induced pSTAT3, and G-15 inhibited E2-induced pSTAT3 in primary cultures of hypothalamic neurons. A cerebroventricular injection of G-1 increased pSTAT3 in the arcuate nucleus of mice, which was associated with a decrease in food intake and body weight gain. These results suggest that GPR30 is the estrogen receptor that mediates the anorectic effect of estrogen through the STAT3 pathway in the hypothalamus. Copyright © 2014 Elsevier Inc. All rights reserved.

Estrogenic Compounds, Estrogen Receptors and Vascular Cell Signaling in the Aging Blood Vessels

PubMed Central

Smiley, Dia A.; Khalil, Raouf A.

2010-01-01

The cardiovascular benefits of menopausal hormone therapy (MHT) remain controversial. The earlier clinical observations that cardiovascular disease (CVD) was less common in MHT users compared to non-users suggested cardiovascular benefits of MHT. Also, experimental studies have identified estrogen receptors ERα, ERβ and GPR30, which mediate genomic or non-genomic effects in vascular endothelium, smooth muscle, and extracellular matrix (ECM). However, data from randomized clinical trials (RCTs), most notably the Women's Health Initiative (WHI) study, have challenged the cardiovascular benefits and highlighted adverse cardiovascular events with MHT. The discrepancies have been attributed to the design of RCTs, the subjects' advanced age and preexisting CVD, and the form of estrogen used. The discrepancies may also stem from age-related changes in vascular ER amount, distribution, integrity, and post-receptor signaling pathways as well as structural changes in the vasculature. Age-related changes in other sex hormones such as testosterone may also alter the hormonal environment and influence the cardiovascular effects of estrogen. Investigating the chemical properties, structure-activity relationship and pharmacology of natural and synthetic estrogens should improve the effectiveness of conventional MHT. Further characterization of phytoestrogens, selective estrogen-receptor modulators (SERMs), and specific ER agonists may provide substitutes to conventional MHT. Conditions with excess or low estrogen levels such as polycystic ovary syndrome (PCOS) and Turner syndrome may provide insight into the development and regulation of ER and the mechanisms of aberrant estrogen-ER interactions. The lessons learned from previous RCTs have led to more directed studies such as the Kronos Early Estrogen Prevention Study (KEEPS). Careful design of experimental models and RCTs, coupled with the development of specific ER modulators, hold the promise of improving the actions of

Rapid effects of estrogens on short-term memory: Possible mechanisms.

PubMed

Paletta, Pietro; Sheppard, Paul A S; Matta, Richard; Ervin, Kelsy S J; Choleris, Elena

2018-06-01

Estrogens affect learning and memory through rapid and delayed mechanisms. Here we review studies on rapid effects on short-term memory. Estradiol rapidly improves social and object recognition memory, spatial memory, and social learning when administered systemically. The dorsal hippocampus mediates estrogen rapid facilitation of object, social and spatial short-term memory. The medial amygdala mediates rapid facilitation of social recognition. The three estrogen receptors, α (ERα), β (ERβ) and the G-protein coupled estrogen receptor (GPER) appear to play different roles depending on the task and brain region. Both ERα and GPER agonists rapidly facilitate short-term social and object recognition and spatial memory when administered systemically or into the dorsal hippocampus and facilitate social recognition in the medial amygdala. Conversely, only GPER can facilitate social learning after systemic treatment and an ERβ agonist only rapidly improved short-term spatial memory when given systemically or into the hippocampus, but also facilitates social recognition in the medial amygdala. Investigations into the mechanisms behind estrogens' rapid effects on short term memory showed an involvement of the extracellular signal-regulated kinase (ERK) and the phosphoinositide 3-kinase (PI3K) kinase pathways. Recent evidence also showed that estrogens interact with the neuropeptide oxytocin in rapidly facilitating social recognition. Estrogens can increase the production and/or release of oxytocin and other neurotransmitters, such as dopamine and acetylcholine. Therefore, it is possible that estrogens' rapid effects on short-term memory may occur through the regulation of various neurotransmitters, although more research is need on these interactions as well as the mechanisms of estrogens' actions on short-term memory. Copyright © 2018 Elsevier Inc. All rights reserved.

Induction of osteoblast differentiation by selective activation of kinase-mediated actions of the estrogen receptor.

PubMed

Kousteni, Stavroula; Almeida, Maria; Han, Li; Bellido, Teresita; Jilka, Robert L; Manolagas, Stavros C

2007-02-01

Estrogens control gene transcription by cis or trans interactions of the estrogen receptor (ER) with target DNA or via the activation of cytoplasmic kinases. We report that selective activation of kinase-mediated actions of the ER with 4-estren-3alpha,17beta-diol (estren) or an estradiol-dendrimer conjugate, each a synthetic compound that stimulates kinase-mediated ER actions 1,000 to 10,000 times more potently than direct DNA interactions, induced osteoblastic differentiation in established cell lines of uncommitted osteoblast precursors and primary cultures of osteoblast progenitors by stimulating Wnt and BMP-2 signaling in a kinase-dependent manner. In sharp contrast, 17beta-estradiol (E(2)) suppressed BMP-2-induced osteoblast progenitor commitment and differentiation. Consistent with the in vitro findings, estren, but not E(2), stimulated Wnt/beta-catenin-mediated transcription in T-cell factor-lacZ transgenic mice. Moreover, E(2) stimulated BMP signaling in mice in which ERalpha lacks DNA binding activity and classical estrogen response element-mediated transcription (ERalpha(NERKI/-)) but not in wild-type controls. This evidence reveals for the first time the existence of a large signalosome in which inputs from the ER, kinases, bone morphogenetic proteins, and Wnt signaling converge to induce differentiation of osteoblast precursors. ER can either induce it or repress it, depending on whether the activating ligand (and presumably the resulting conformation of the receptor protein) precludes or accommodates ERE-mediated transcription.

Mechanical loading increases detection of estrogen receptor-alpha in osteocytes and osteoblasts despite chronic energy restriction.

PubMed

Swift, Sibyl N; Swift, Joshua M; Bloomfield, Susan A

2014-12-01

Estrogen receptor-α (ER-α) is an important mediator of the bone response to mechanical loading. We sought to determine whether restricting dietary energy intake by 40% limits the bone formation rate (BFR) response to mechanical loading (LOAD) by downregulating ER-α-expressing osteocytes, or osteoblasts, or both. Female rats (n = 48, 7 mo old) were randomized to ADLIB-SHAM and ADLIB-LOAD groups fed AIN-93M purified diet ad libitum or to ER40-SHAM and ER40-LOAD groups fed modified AIN-93M with 40% less energy (100% of all other nutrients). After 12 wk, LOAD rats were subjected to a muscle contraction protocol three times every third day. ER40 produced lower proximal tibia bone volume (-22%), trabecular thickness (-14%), and higher trabecular separation (+127%) in SHAM but not LOAD rats. ER40 rats exhibited reductions in mineral apposition rate, but not percent mineralizing surface or BFR. LOAD induced similar relative increases in these kinetic measures of osteoblast activity/recruitment in both diet groups., but absolute values for ER40 LOAD rats were lower vs. ADLIB-LOAD. There were fourfold and eightfold increases in proportion of estrogen receptor-α protein-positive osteoblast and osteocytes, respectively, in LOAD vs. SHAM rats, with no effect of ER40. These data suggest that a brief period of mechanical loading significantly affects estrogen receptor-α in cancellous bone osteoblasts and osteocytes. Chronic energy restriction does result in lower absolute values in indices of osteoblast activity after mechanical loading, but not by a smaller increment relative to unloaded bones; this change is not explained by an associated downregulation of ER-α in osteoblasts or osteocytes.

Estrogen signaling through the G protein-coupled estrogen receptor regulates granulocyte activation in fish.

PubMed

Cabas, Isabel; Rodenas, M Carmen; Abellán, Emilia; Meseguer, José; Mulero, Victoriano; García-Ayala, Alfonsa

2013-11-01

Neutrophils are major participants in innate host responses. It is well known that estrogens have an immune-modulatory role, and some evidence exists that neutrophil physiology can be altered by these molecules. Traditionally, estrogens act via classical nuclear estrogen receptors, but the identification of a G protein-coupled estrogen receptor (GPER), a membrane estrogen receptor that binds estradiol and other estrogens, has opened up the possibility of exploring additional estrogen-mediated effects. However, information on the importance of GPER for immunity, especially, in neutrophils is scant. In this study, we report that gilthead seabream (Sparus aurata L.) acidophilic granulocytes, which are the functional equivalent of mammalian neutrophils, express GPER at both mRNA and protein levels. By using a GPER selective agonist, G1, it was found that GPER activation in vitro slightly reduced the respiratory burst of acidophilic granulocytes and drastically altered the expression profile of several genes encoding major pro- and anti-inflammatory mediators. In addition, GPER signaling in vivo modulated adaptive immunity. Finally, a cAMP analog mimicked the effects of G1 in the induction of the gene coding for PG-endoperoxide synthase 2 and in the induction of CREB phosphorylation, whereas pharmacological inhibition of protein kinase A superinduced PG-endoperoxide synthase 2. Taken together, our results demonstrate for the first time, to our knowledge, that estrogens are able to modulate vertebrate granulocyte functions through a GPER/cAMP/protein kinase A/CREB signaling pathway and could establish therapeutic targets for several immune disorders in which estrogens play a prominent role.

The Dual Estrogen Receptor α Inhibitory Effects of the Tissue-Selective Estrogen Complex for Endometrial and Breast Safety

PubMed Central

Han, Sang Jun; Begum, Khurshida; Foulds, Charles E.; Hamilton, Ross A.; Bailey, Suzanna; Malovannaya, Anna; Chan, Doug; Qin, Jun

2016-01-01

The conjugated estrogen/bazedoxifene tissue-selective estrogen complex (TSEC) is designed to minimize the undesirable effects of estrogen in the uterus and breast tissues and to allow the beneficial effects of estrogen in other estrogen-target tissues, such as the bone and brain. However, the molecular mechanism underlying endometrial and breast safety during TSEC use is not fully understood. Estrogen receptor α (ERα)–estrogen response element (ERE)–DNA pull-down assays using HeLa nuclear extracts followed by mass spectrometry–immunoblotting analyses revealed that, upon TSEC treatment, ERα interacted with transcriptional repressors rather than coactivators. Therefore, the TSEC-mediated recruitment of transcriptional repressors suppresses ERα-mediated transcription in the breast and uterus. In addition, TSEC treatment also degraded ERα protein in uterine tissue and breast cancer cells, but not in bone cells. Interestingly, ERα-ERE-DNA pull-down assays also revealed that, upon TSEC treatment, ERα interacted with the F-box protein 45 (FBXO45) E3 ubiquitin ligase. The loss-of- and gain-of-FBXO45 function analyses indicated that FBXO45 is involved in TSEC-mediated degradation of the ERα protein in endometrial and breast cells. In preclinical studies, these synergistic effects of TSEC on ERα inhibition also suppressed the estrogen-dependent progression of endometriosis. Therefore, the endometrial and breast safety effects of TSEC are associated with synergy between the selective recruitment of transcriptional repressors to ERα and FBXO45-mediated degradation of the ERα protein. PMID:26487511

Estrogen receptor coregulator binding modulators (ERXs) effectively target estrogen receptor positive human breast cancers

PubMed Central

Raj, Ganesh V; Sareddy, Gangadhara Reddy; Ma, Shihong; Lee, Tae-Kyung; Viswanadhapalli, Suryavathi; Li, Rui; Liu, Xihui; Murakami, Shino; Chen, Chien-Cheng; Lee, Wan-Ru; Mann, Monica; Krishnan, Samaya Rajeshwari; Manandhar, Bikash; Gonugunta, Vijay K; Strand, Douglas; Tekmal, Rajeshwar Rao; Ahn, Jung-Mo; Vadlamudi, Ratna K

2017-01-01

The majority of human breast cancer is estrogen receptor alpha (ER) positive. While anti-estrogens/aromatase inhibitors are initially effective, resistance to these drugs commonly develops. Therapy-resistant tumors often retain ER signaling, via interaction with critical oncogenic coregulator proteins. To address these mechanisms of resistance, we have developed a novel ER coregulator binding modulator, ERX-11. ERX-11 interacts directly with ER and blocks the interaction between a subset of coregulators with both native and mutant forms of ER. ERX-11 effectively blocks ER-mediated oncogenic signaling and has potent anti-proliferative activity against therapy-sensitive and therapy-resistant human breast cancer cells. ERX-11 is orally bioavailable, with no overt signs of toxicity and potent activity in both murine xenograft and patient-derived breast tumor explant models. This first-in-class agent, with its novel mechanism of action of disrupting critical protein-protein interactions, overcomes the limitations of current therapies and may be clinically translatable for patients with therapy-sensitive and therapy-resistant breast cancers. DOI: http://dx.doi.org/10.7554/eLife.26857.001 PMID:28786813

Binding and transactivation of the largemouth bass estrogen receptors by model compounds

EPA Science Inventory

Environmental estrogens (EEs) are chemicals in the environment that can elicit adverse effects on estrogen (E2) signaling by binding with the estrogen receptors (ERs). In largemouth bass (LMB), the physiological actions of E2 are primarily mediated via three receptors (ERα, ERßb ...

DNA Repair, Redox Regulation and Modulation of Estrogen Receptor Alpha Mediated Transcription

ERIC Educational Resources Information Center

Curtis-Ducey, Carol Dianne

2009-01-01

Interaction of estrogen receptor [alpha] (ER[alpha]) with 17[beta]-estradiol (E[subscript 2]) facilitates binding of the receptor to estrogen response elements (EREs) in target genes, which in turn leads to recruitment of coregulatory proteins. To better understand how estrogen-responsive genes are regulated, our laboratory identified a number of…

Sex Hormones and Cardiometabolic Health: Role of Estrogen and Estrogen Receptors.

PubMed

Clegg, Deborah; Hevener, Andrea L; Moreau, Kerrie L; Morselli, Eugenia; Criollo, Alfredo; Van Pelt, Rachael E; Vieira-Potter, Victoria J

2017-05-01

With increased life expectancy, women will spend over three decades of life postmenopause. The menopausal transition increases susceptibility to metabolic diseases such as obesity, diabetes, cardiovascular disease, and cancer. Thus, it is more important than ever to develop effective hormonal treatment strategies to protect aging women. Understanding the role of estrogens, and their biological actions mediated by estrogen receptors (ERs), in the regulation of cardiometabolic health is of paramount importance to discover novel targeted therapeutics. In this brief review, we provide a detailed overview of the literature, from basic science findings to human clinical trial evidence, supporting a protective role of estrogens and their receptors, specifically ERα, in maintenance of cardiometabolic health. In so doing, we provide a concise mechanistic discussion of some of the major tissue-specific roles of estrogens signaling through ERα. Taken together, evidence suggests that targeted, perhaps receptor-specific, hormonal therapies can and should be used to optimize the health of women as they transition through menopause, while reducing the undesired complications that have limited the efficacy and use of traditional hormone replacement interventions. Copyright © 2017 Endocrine Society.

Estrogen promotes cutaneous wound healing via estrogen receptor β independent of its antiinflammatory activities

PubMed Central

Campbell, Laura; Emmerson, Elaine; Davies, Faith; Gilliver, Stephen C.; Krust, Andre; Chambon, Pierre; Ashcroft, Gillian S.

2010-01-01

Post-menopausal women have an increased risk of developing a number of degenerative pathological conditions, linked by the common theme of excessive inflammation. Systemic estrogen replacement (in the form of hormone replacement therapy) is able to accelerate healing of acute cutaneous wounds in elderly females, linked to its potent antiinflammatory activity. However, in contrast to many other age-associated pathologies, the detailed mechanisms through which estrogen modulates skin repair, particularly the cell type–specific role of the two estrogen receptors, ERα and ERβ, has yet to be determined. Here, we use pharmacological activation and genetic deletion to investigate the role of both ERα and ERβ in cutaneous tissue repair. Unexpectedly, we report that exogenous estrogen replacement to ovariectomised mice in the absence of ERβ actually delayed wound healing. Moreover, healing in epidermal-specific ERβ null mice (K14-cre/ERβL2/L2) largely resembled that in global ERβ null mice. Thus, the beneficial effects of estrogen on skin wound healing are mediated by epidermal ERβ, in marked contrast to most other tissues in the body where ERα is predominant. Surprisingly, agonists to both ERα and ERβ are potently antiinflammatory during skin repair, indicating clear uncoupling of inflammation and overall efficiency of repair. Thus, estrogen-mediated antiinflammatory activity is not the principal factor in accelerated wound healing. PMID:20733032

Obesity, Insulin Resistance and Diabetes: Sex Differences and Role of Estrogen Receptors

PubMed Central

Meyer, Matthias R.; Clegg, Deborah J.; Prossnitz, Eric R.; Barton, Matthias

2010-01-01

Obesity increases the risk of coronary artery disease through insulin resistance, diabetes, arterial hypertension, and dyslipidemia. The prevalence of obesity has increased worldwide and is particularly high among middle-aged women and men. After menopause, women are at an increased risk to develop visceral obesity due to the loss of endogenous ovarian hormone production. Effects of estrogens are classically mediated by the two nuclear estrogen receptors (ERs) α and β. In addition, more recent research has shown that the intracellular transmembrane G protein-coupled estrogen receptor, GPER, originally designated as GPR30, also mediates some of the actions attributed to estrogens. Estrogen and its receptors are important regulators of body weight and insulin sensitivity not only in women, but also in men as demonstrated by ER mutations in rodents and humans. This article reviews the role of sex hormones and estrogen receptors in the context of obesity, insulin sensitivity and diabetes as well as the related clinical issues in females and males. PMID:21281456

Retinoid X receptor and peroxisome proliferator-activated receptor activate an estrogen responsive gene independent of the estrogen receptor.

PubMed

Nuñez, S B; Medin, J A; Braissant, O; Kemp, L; Wahli, W; Ozato, K; Segars, J H

1997-03-14

Estrogen receptors regulate transcription of genes essential for sexual development and reproductive function. Since the retinoid X receptor (RXR) is able to modulate estrogen responsive genes and both 9-cis RA and fatty acids influenced development of estrogen responsive tumors, we hypothesized that estrogen responsive genes might be modulated by RXR and the fatty acid receptor (peroxisome proliferator-activated receptor, PPAR). To test this hypothesis, transfection assays in CV-1 cells were performed with an estrogen response element (ERE) coupled to a luciferase reporter construct. Addition of expression vectors for RXR and PPAR resulted in an 11-fold increase in luciferase activity in the presence of 9-cis RA. Furthermore, mobility shift assays demonstrated binding of RXR and PPAR to the vitellogenin A2-ERE and an ERE in the oxytocin promoter. Methylation interference assays demonstrated that specific guanine residues required for RXR/PPAR binding to the ERE were similar to residues required for ER binding. Moreover, RXR domain-deleted constructs in transfection assays showed that activation required RXR since an RXR delta AF-2 mutant completely abrogated reporter activity. Oligoprecipitation binding studies with biotinylated ERE and (35)S-labeled in vitro translated RXR constructs confirmed binding of delta AF-2 RXR mutant to the ERE in the presence of baculovirus-expressed PPAR. Finally, in situ hybridization confirmed RXR and PPAR mRNA expression in estrogen responsive tissues. Collectively, these data suggest that RXR and PPAR are present in reproductive tissues, are capable of activating estrogen responsive genes and suggest that the mechanism of activation may involve direct binding of the receptors to estrogen response elements.

Estrogen Enhances Linkage in the Vascular Endothelial Calmodulin Network via a Feedforward Mechanism at the G Protein-coupled Estrogen Receptor 1*

PubMed Central

Tran, Quang-Kim; Firkins, Rachel; Giles, Jennifer; Francis, Sarah; Matnishian, Vahe; Tran, Phuong; VerMeer, Mark; Jasurda, Jake; Burgard, Michelle Ann; Gebert-Oberle, Briana

2016-01-01

Estrogen exerts many effects on the vascular endothelium. Calmodulin (CaM) is the transducer of Ca2+ signals and is a limiting factor in cardiovascular tissues. It is unknown whether and how estrogen modifies endothelial functions via the network of CaM-dependent proteins. Here we show that 17β-estradiol (E2) up-regulates total CaM level in endothelial cells. Concurrent measurement of Ca2+ and Ca2+-CaM indicated that E2 also increases free Ca2+-CaM. Pharmacological studies, gene silencing, and receptor expression-specific cell studies indicated that the G protein-coupled estrogen receptor 1 (GPER/GPR30) mediates these effects via transactivation of EGFR and subsequent MAPK activation. The outcomes were then examined on four distinct members of the intracellular CaM target network, including GPER/GPR30 itself and estrogen receptor α, the plasma membrane Ca2+-ATPase (PMCA), and endothelial nitric-oxide synthase (eNOS). E2 substantially increases CaM binding to estrogen receptor α and GPER/GPR30. Mutations that reduced CaM binding to GPER/GPR30 in separate binding domains do not affect GPER/GPR30-Gβγ preassociation but decrease GPER/GPR30-mediated ERK1/2 phosphorylation. E2 increases CaM-PMCA association, but the expected stimulation of Ca2+ efflux is reversed by E2-stimulated tyrosine phosphorylation of PMCA. These effects sustain Ca2+ signals and promote Ca2+-dependent CaM interactions with other CaM targets. Consequently, E2 doubles CaM-eNOS interaction and also promotes dual phosphorylation of eNOS at Ser-617 and Ser-1179. Calculations using in-cell and in vitro data revealed substantial individual and combined contribution of these effects to total eNOS activity. Taken together, E2 generates a feedforward loop via GPER/GPR30, which enhances Ca2+/CaM signals and functional linkage in the endothelial CaM target network. PMID:26987903

Estrogen Enhances Linkage in the Vascular Endothelial Calmodulin Network via a Feedforward Mechanism at the G Protein-coupled Estrogen Receptor 1.

PubMed

Tran, Quang-Kim; Firkins, Rachel; Giles, Jennifer; Francis, Sarah; Matnishian, Vahe; Tran, Phuong; VerMeer, Mark; Jasurda, Jake; Burgard, Michelle Ann; Gebert-Oberle, Briana

2016-05-13

Estrogen exerts many effects on the vascular endothelium. Calmodulin (CaM) is the transducer of Ca(2+) signals and is a limiting factor in cardiovascular tissues. It is unknown whether and how estrogen modifies endothelial functions via the network of CaM-dependent proteins. Here we show that 17β-estradiol (E2) up-regulates total CaM level in endothelial cells. Concurrent measurement of Ca(2+) and Ca(2+)-CaM indicated that E2 also increases free Ca(2+)-CaM. Pharmacological studies, gene silencing, and receptor expression-specific cell studies indicated that the G protein-coupled estrogen receptor 1 (GPER/GPR30) mediates these effects via transactivation of EGFR and subsequent MAPK activation. The outcomes were then examined on four distinct members of the intracellular CaM target network, including GPER/GPR30 itself and estrogen receptor α, the plasma membrane Ca(2+)-ATPase (PMCA), and endothelial nitric-oxide synthase (eNOS). E2 substantially increases CaM binding to estrogen receptor α and GPER/GPR30. Mutations that reduced CaM binding to GPER/GPR30 in separate binding domains do not affect GPER/GPR30-Gβγ preassociation but decrease GPER/GPR30-mediated ERK1/2 phosphorylation. E2 increases CaM-PMCA association, but the expected stimulation of Ca(2+) efflux is reversed by E2-stimulated tyrosine phosphorylation of PMCA. These effects sustain Ca(2+) signals and promote Ca(2+)-dependent CaM interactions with other CaM targets. Consequently, E2 doubles CaM-eNOS interaction and also promotes dual phosphorylation of eNOS at Ser-617 and Ser-1179. Calculations using in-cell and in vitro data revealed substantial individual and combined contribution of these effects to total eNOS activity. Taken together, E2 generates a feedforward loop via GPER/GPR30, which enhances Ca(2+)/CaM signals and functional linkage in the endothelial CaM target network. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

Estrogen Receptors Alpha and Beta in Bone

PubMed Central

Khalid, Aysha B.; Krum, Susan A.

2016-01-01

Estrogens are important for bone metabolism via a variety of mechanisms in osteoblasts, osteocytes, osteoclasts, immune cells and other cells to maintain bone mineral density. Estrogens bind to estrogen receptor alpha (ERα) and ERβ, and the roles of each of these receptors are beginning to be elucidated through whole body and tissue-specific knockouts of the receptors. In vitro and in vivo experiments have shown that ERα and ERβ antagonize each other in bone and in other tissues. This review will highlight the role of these receptors in bone, with particular emphasis on their antagonism. PMID:27072516

Estrogen Receptor-Related Receptor α Mediates Up-Regulation of Aromatase Expression by Prostaglandin E2 in Prostate Stromal Cells

PubMed Central

Miao, Lin; Shi, Jiandang; Wang, Chun-Yu; Zhu, Yan; Du, Xiaoling; Jiao, Hongli; Mo, Zengnan; Klocker, Helmut; Lee, Chung; Zhang, Ju

2010-01-01

Estrogen receptor-related receptor α (ERRα) is an orphan member of the nuclear receptor superfamily of transcription factors. ERRα is highly expressed in the prostate, especially in prostate stromal cells. However, little is known about the regulation and function of ERRα, which may contribute to the progression of prostatic diseases. We previously found that prostaglandin E2 (PGE2) up-regulated the expression of aromatase in prostate stromal cells. Here we show that PGE2 also up-regulates the expression of ERRα, which, as a transcription factor, further mediates the regulatory effects of PGE2 on the expression of aromatase. ERRα expression was up-regulated by PGE2 in prostate stromal cell line WPMY-1, which was mediated mainly through the protein kinase A signaling pathway by PGE2 receptor EP2. Suppression of ERRα activity by chlordane (an antagonist of ERRα) or small interfering RNA knockdown of ERRα blocked the increase of expression and promoter activity of aromatase induced by PGE2. Overexpression of ERRα significantly increased aromatase expression and promoter activity, which were further augmented by PGE2. Chromatin immunoprecipitation assay demonstrated that ERRα directly bound to the aromatase promoter in vivo, and PGE2 enhanced the recruitment of ERRα and promoted transcriptional regulatory effects on aromatase expression in WPMY-1. 17β-Estradiol concentration in WPMY-1 medium was up-regulated by ERRα expression, and that was further increased by PGE2. Our results provided evidence that ERRα contributed to local estrogen production by up-regulating aromatase expression in response to PGE2 and provided further insights into the potential role of ERRα in estrogen-related prostatic diseases. PMID:20351196

Estrogen-Induced Developmental Disorders of the Rat Penis Involve Both Estrogen Receptor (ESR)- and Androgen Receptor (AR)-Mediated Pathways1

PubMed Central

Goyal, H.O.; Braden, T.D.; Williams, C.S.; Williams, J.W.

2009-01-01

This study tested the hypothesis that the estrogen receptor (ESR) pathway, androgen receptor (AR) pathway, or both mediate estrogen-induced developmental penile disorders. Rat pups received diethylstilbestrol (DES), with or without the ESR antagonist ICI 182,780 (ICI) or the AR agonist dihydrotestosterone (DHT) or testosterone (T), from Postnatal Days 1 to 6. Testicular T concentration, penile morphology and morphometry, and/or fertility was determined at age 7, 28, or 150 days. DES treatment alone caused 90% reduction in the neonatal intratesticular T surge; this reduction was prevented by ICI coadministration, but not by DHT or T coadministration. Unlike the T surge, coadministration of ICI and coadministration of DHT or T mitigated penile deformities and loss of fertility. Generally, ICI, DHT, or T treatment alone did not alter penile morphology; however, fertility was 20% that of controls in ICI-treated rats vs. 70%–90% in DHT- or T-treated rats. The lower fertility in the rats treated with ICI alone could be due to altered sexual behavior, as these males did not deposit vaginal plugs. In conclusion, observations that both an ESR antagonist and AR agonists prevent penile deformities and infertility suggest that both pathways are involved in estrogen-induced penile disorders. Observations that coadministration of ICI, but not DHT or T, prevents the DES-induced reduction in the neonatal T surge suggest that, although ICI exerts its mitigating effect both at the level of Leydig cells and penile stromal cells, DHT and T do so only at the level of stromal cells. PMID:19420389

A role for G-protein coupled estrogen receptor (GPER) in estrogen-induced carcinogenesis: Dysregulated glandular homeostasis, survival and metastasis.

PubMed

Filardo, Edward J

2018-02-01

Mechanisms of carcinogenesis by estrogen center on its mitogenic and genotoxic potential on tumor target cells. These models suggest that estrogen receptor (ER) signaling promotes expansion of the transformed population and that subsequent accumulation of somatic mutations that drive cancer progression occur via metabolic activation of cathecol estrogens or by epigenetic mechanisms. Recent findings that GPER is linked to obesity, vascular pathology and immunosuppression, key events in the development of metabolic syndrome and intra-tissular estrogen synthesis, provides an alternate view of estrogen-induced carcinogenesis. Consistent with this concept, GPER is directly associated with clinicopathological indices that predict cancer progression and poor survival in breast and gynecological cancers. Moreover, GPER manifests cell biological responses and a microenvironment conducive for tumor development and cancer progression, regulating cellular responses associated with glandular homeostasis and survival, invading surrounding tissue and attracting a vascular supply. Thus, the cellular actions attributed to GPER fit well with the known molecular mechanisms of G-protein coupled receptors, GPCRs, namely, their ability to transactivate integrins and EGF receptors and alter the interaction between glandular epithelia and their extracellular environment, affecting epithelial-to-mesenchymal transition (EMT) and allowing for tumor cell survival and dissemination. This perspective reviews the molecular and cellular responses manifested by GPER and evaluates its contribution to female reproductive cancers as diseases that progress as a result of dysregulated glandular homeostasis resulting in chronic inflammation and metastasis. This review is organized in sections as follows: I) a brief synopsis of the current state of knowledge regarding estrogen-induced carcinogenesis, II) a review of evidence from clinical and animal-based studies that support a role for GPER in cancer

Epidermal growth factor receptor (EGFR) transactivation by estrogen via the G-protein-coupled receptor, GPR30: a novel signaling pathway with potential significance for breast cancer.

PubMed

Filardo, Edward J

2002-02-01

The biological and biochemical effects of estrogen have been ascribed to its known receptors, which function as ligand-inducible transcription factors. However, estrogen also triggers rapid activation of classical second messengers (cAMP, calcium, and inositol triphosphate) and stimulation of intracellular signaling cascades mitogen-activated protein kinase (MAP K), PI3K and eNOS. These latter events are commonly activated by membrane receptors that either possess intrinsic tyrosine kinase activity or couple to heterotrimeric G-proteins. We have shown that estrogen transactivates the epidermal growth factor receptor (EGFR) to MAP K signaling axis via the G-protein-coupled receptor (GPCR), GPR30, through the release of surface-bound proHB-EGF from estrogen receptor (ER)-negative human breast cancer cells [Molecular Endocrinology 14 (2000) 1649]. This finding is consistent with a growing body of evidence suggesting that transactivation of EGFRs by GPCRs is a recurrent theme in cell signaling. GPCR-mediated transactivation of EGFRs by estrogen provides a previously unappreciated mechanism of cross-talk between estrogen and serum growth factors, and explains prior data reporting the EGF-like effects of estrogen. This novel mechanism by which estrogen activates growth factor-dependent signaling and its implications for breast cancer biology are discussed further in this review.

GPER mediates activation of HIF1α/VEGF signaling by estrogens.

PubMed

De Francesco, Ernestina Marianna; Pellegrino, Michele; Santolla, Maria Francesca; Lappano, Rosamaria; Ricchio, Emilia; Abonante, Sergio; Maggiolini, Marcello

2014-08-01

Biological responses to estrogens in normal and malignant tissues are mainly mediated by the estrogen receptors ERα and ERβ, which function as ligand-activated transcription factors. In addition, the G protein-coupled receptor GPR30 (GPER) mediates estrogenic signaling in breast cancer cells and cancer-associated fibroblasts (CAF) that contribute to cancer progression. In this study, we evaluated the role elicited by GPER in the estrogen-regulated expression and function of vascular endothelial growth factor (VEGF) in ER-negative breast cancer cells and CAF. We demonstrated that 17β-estradiol (E2) and the GPER-selective ligand G-1 triggered a GPER/EGFR/ERK/c-fos signaling pathway that leads to increased VEGF via upregulation of HIF1α. In further extending the mechanisms involved in E2-supported angiogenesis, we also showed that conditioned medium from CAF treated with E2 and G-1 promoted human endothelial tube formation in a GPER-dependent manner. In vivo, ligand-activated GPER was sufficient to enhance tumor growth and the expression of HIF1α, VEGF, and the endothelial marker CD34 in a mouse xenograft model of breast cancer. Our findings offer important new insights into the ability of estrogenic GPER signaling to trigger HIF1α-dependent VEGF expression that supports angiogenesis and progression in breast cancer. ©2014 American Association for Cancer Research.

Estetrol, a Fetal Selective Estrogen Receptor Modulator, Acts on the Vagina of Mice through Nuclear Estrogen Receptor α Activation.

PubMed

Benoit, Thibaut; Valera, Marie-Cecile; Fontaine, Coralie; Buscato, Melissa; Lenfant, Francoise; Raymond-Letron, Isabelle; Tremollieres, Florence; Soulie, Michel; Foidart, Jean-Michel; Game, Xavier; Arnal, Jean-Francois

2017-11-01

The genitourinary syndrome of menopause has a negative impact on quality of life of postmenopausal women. The treatment of vulvovaginal atrophy includes administration of estrogens. However, oral estrogen treatment is controversial because of its potential risks on venous thrombosis and breast cancer. Estetrol (E4) is a natural estrogen synthesized exclusively during pregnancy by the human fetal liver and initially considered as a weak estrogen. However, E4 was recently evaluated in phase 1 to 2 clinical studies and found to act as an oral contraceptive in combination with a progestin, without increasing the level of coagulation factors. We recently showed that E4 stimulates uterine epithelial proliferation through nuclear estrogen receptor (ER) α, but failed to elicit endothelial responses. Herein, we first evaluated the morphological and functional impacts of E4 on the vagina of ovariectomized mice, and we determined the molecular mechanism mediating these effects. Vaginal epithelial proliferation and lubrication after stimulation were found to increase after E4 chronic treatment. Using a combination of pharmacological and genetic approaches, we demonstrated that these E4 effects on the vagina are mediated by nuclear ERα activation. Altogether, we demonstrate that the selective activation of nuclear ERα is both necessary and sufficient to elicit functional and structural effects on the vagina, and therefore E4 appears promising as a therapeutic option to improve vulvovaginal atrophy. Copyright © 2017 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.

ICI 182,780-regulated gene expression in DU145 prostate cancer cells is mediated by estrogen receptor-beta/NFkappaB crosstalk.

PubMed

Leung, Yuet-Kin; Gao, Ying; Lau, Kin-Mang; Zhang, Xiang; Ho, Shuk-Mei

2006-04-01

Estrogen receptor (ER)-beta is the predominant ER subtype in prostate cancer (PCa). We previously demonstrated that ICI 182,780 (ICI), but not estrogens, exerted dose-dependent growth inhibition on DU145 PCa cells by an ER-beta-mediated pathway. Transcriptional profiling detected a greater than three-fold upregulation of seven genes after a 12-hour exposure to 1 microM ICI. Semiquantitative reverse transcriptase polymerase chain reaction confirmed the upregulation of four genes by ICI: interleukin-12alpha chain, interleukin-8, embryonic growth/differentiation factor, and RYK tyrosine kinase. Treatment with an ER-beta antisense oligonucleotide reduced cellular ER-beta mRNA and induced loss of expression of these genes. Sequence analysis revealed the presence of consensus NFkappaB sites, but not estrogen-responsive elements, in promoters of all four genes. Reporter assay and chromatin immunoprecipitation experiments demonstrated that ICI-induced gene expression could be mediated by crosstalk between ER-beta and the NFkappaB signaling pathway, denoting a novel mechanism of ER-beta-mediated ICI action. Therefore, combined therapies targeting ER-beta and NFkappaB signaling may be synergistic as treatment for PCa.

Extracellular matrix integrity: a possible mechanism for differential clinical effects among selective estrogen receptor modulators and estrogens?

PubMed

Cox, David A; Helvering, Leah M

2006-03-09

Recent gene microarray studies have illustrated heterogeneity in gene expression changes not only between estrogens and selective estrogen receptor modulators (SERMs), but also across different SERM molecules. In ovariectomized rats, this phenomenon was observed with respect to a number of genes involved in collagen turnover and extracellular matrix (ECM) integrity in the uterus and vaginal tissues. Preliminary mechanistic data suggest that these effects on ECM integrity may have relevance in the context of the effect of estrogens and some SERMs to increase the risk of pelvic organ prolapse and the incidence of urinary incontinence in postmenopausal women. Given the pivotal role of ECM integrity and collagen turnover in other tissues and disease states, these processes may provide a fruitful target for future research into the mechanisms for the heterogeneous pharmacology of estrogens and SERMs across different cell types and target tissues.

The Distinct Effects of Estrogen and Hydrostatic Pressure on Mesenchymal Stem Cells Differentiation: Involvement of Estrogen Receptor Signaling.

PubMed

Zhao, Ying; Yi, Fei-Zhou; Zhao, Yin-Hua; Chen, Yong-Jin; Ma, Heng; Zhang, Min

2016-10-01

This study aimed to investigate the differential and synergistic effects of mechanical stimulation and estrogen on the proliferation and osteogenic or chondrogenic differentiation potential of bone marrow mesenchymal stem cells (BMSCs) and the roles of estrogen receptor (ER) in them. BMSCs were isolated and cultured using the whole bone marrow adherence method, and flow cytometry was used to identify the surface marker molecules of BMSCs. Cells were pre-treated with 1 nM 17β-estradiol or 1 nM of the estrogen receptor antagonist tamoxifen. Then, the cells were stimulated with hydrostatic pressure. Assessment included flow cytometry analysis of the cell cycle; immunofluorescent staining for F-actin; protein quantification for MAPK protein; and mRNA analysis for Col I, OCN, OPN and BSP after osteogenic induction and Sox-9, Aggrecan and Col-II after chondrogenic induction. Hydrostatic pressure (90 kPa/1 h) and 1 nM 17β-estradiol enhanced the cellular proliferation ability and the cytoskeleton activity but without synergistic biological effects. Estrogen activated ERKs and JNKs simultaneously and promoted the osteogenic differentiation, whereas the pressure just caused JNK-1/2 activation and promoted the chondrogenic differentiation of BMSCs. Estrogen had antagonism effect on chondrogenic promotion of hydrostatic pressure. Mechanobiological effects of hydrostatic pressure are closely associated with ERα activity. MAPK molecules and F-actin were likely to be important mediator molecules in the ER-mediated mechanotransduction of BMSCs.

Estrogen promotes the brain metastatic colonization of triple negative breast cancer cells via an astrocyte-mediated paracrine mechanism.

PubMed

Sartorius, C A; Hanna, C T; Gril, B; Cruz, H; Serkova, N J; Huber, K M; Kabos, P; Schedin, T B; Borges, V F; Steeg, P S; Cittelly, D M

2016-06-02

Brain metastases (BM) are a devastating consequence of breast cancer. BM occur more frequently in patients with estrogen receptor-negative (ER-) breast cancer subtypes; HER2 overexpressing (HER2+) tumors and triple-negative (TN) (ER-, progesterone receptor-negative (PR-) and normal HER2) tumors. Young age is an independent risk factor for the development of BM, thus we speculated that higher circulating estrogens in young, pre-menopausal women could exert paracrine effects through the highly estrogen-responsive brain microenvironment. Using a TN experimental metastases model, we demonstrate that ovariectomy decreased the frequency of magnetic resonance imaging-detectable lesions by 56% as compared with estrogen supplementation, and that the combination of ovariectomy and letrozole further reduced the frequency of large lesions to 14.4% of the estrogen control. Human BM expressed 4.2-48.4% ER+ stromal area, particularly ER+ astrocytes. In vitro, E2-treated astrocytes increased proliferation, migration and invasion of 231BR-EGFP cells in an ER-dependent manner. E2 upregulated epidermal growth factor receptor (EGFR) ligands Egf, Ereg and Tgfa mRNA and protein levels in astrocytes, and activated EGFR in brain metastatic cells. Co-culture of 231BR-EGFP cells with E2-treated astrocytes led to the upregulation of the metastatic mediator S100 Calcium-binding protein A4 (S100A4) (1.78-fold, P<0.05). Exogenous EGF increased S100A4 mRNA levels in 231BR-EGFP cells (1.40±0.02-fold, P<0.01 compared with vehicle control) and an EGFR/HER2 inhibitor blocked this effect, suggesting that S100A4 is a downstream effector of EGFR activation. Short hairpin RNA-mediated S100A4 silencing in 231BR-EGFP cells decreased their migration and invasion in response to E2-CM, abolished their increased proliferation in co-cultures with E2-treated astrocytes and decreased brain metastatic colonization. Thus, S100A4 is one effector of the paracrine action of E2 in brain metastatic cells. These

Involvement of estrogen receptor variant ER-alpha36, not GPR30, in nongenomic estrogen signaling.

PubMed

Kang, Lianguo; Zhang, Xintian; Xie, Yan; Tu, Yaping; Wang, Dong; Liu, Zhenming; Wang, Zhao-Yi

2010-04-01

Accumulating evidence suggested that an orphan G protein-coupled receptor (GPR)30, mediates nongenomic responses to estrogen. The present study was performed to investigate the molecular mechanisms underlying GPR30 function. We found that knockdown of GPR30 expression in breast cancer SK-BR-3 cells down-regulated the expression levels of estrogen receptor (ER)-alpha36, a variant of ER-alpha. Introduction of a GPR30 expression vector into GPR30 nonexpressing cells induced endogenous ER-alpha36 expression, and cotransfection assay demonstrated that GPR30 activated the promoter activity of ER-alpha36 via an activator protein 1 binding site. Both 17beta-estradiol (E2) and G1, a compound reported to be a selective GPR30 agonist, increased the phosphorylation levels of the MAPK/ERK1/2 in SK-BR-3 cells, which could be blocked by an anti-ER-alpha36-specific antibody against its ligand-binding domain. G1 induced activities mediated by ER-alpha36, such as transcription activation activity of a VP16-ER-alpha36 fusion protein and activation of the MAPK/ERK1/2 in ER-alpha36-expressing cells. ER-alpha36-expressing cells, but not the nonexpressing cells, displayed high-affinity, specific E2 and G1 binding, and E2- and G1-induced intracellular Ca(2+) mobilization only in ER-alpha36 expressing cells. Taken together, our results demonstrated that previously reported activities of GPR30 in response to estrogen were through its ability to induce ER-alpha36 expression. The selective G protein-coupled receptor (GPR)30 agonist G1 actually interacts with ER-alpha36. Thus, the ER-alpha variant ER-alpha36, not GPR30, is involved in nongenomic estrogen signaling.

Channel catfish (Ictalurus punctatus) leukocytes express estrogen receptor isoforms ERα and ERβ2 and are functionally modulated by estrogens

USGS Publications Warehouse

Iwanowicz, Luke R.; Stafford, James L.; Patiño, Reynaldo; Bengten, Eva; Miller, Norman W.; Blazer, Vicki

2014-01-01

Estrogens are recognized as modulators of immune responses in mammals and teleosts. While it is known that the effects of estrogens are mediated via leukocyte-specific estrogen receptors (ERs) in humans and mice, leucocyte-specific estrogen receptor expression and the effects of estrogens on this cell population is less explored and poorly understood in teleosts. Here in, we verify that channel catfish (Ictalurus punctaus) leukocytes express ERα and ERβ2. Transcripts of these isoforms were detected in tissue-associated leukocyte populations by PCR, but ERβ2 was rarely detected in PBLs. Expression of these receptors was temporally regulated in PBLs following polyclonal activation by concanavalin A, lipopolysaccharide or alloantigen based on evaluation by quantitative and end-point PCR. Examination of long-term leukocyte cell lines demonstrated that these receptors are differentially expressed depending on leukocyte lineage and phenotype. Expression of ERs was also temporally dynamic in some leukocyte lineages and may reflect stage of cell maturity. Estrogens affect the responsiveness of channel catfish peripheral blood leukocytes (PBLs) to mitogens in vitro. Similarly, bactericidal activity and phorbol 12-myristate 13-acetate induced respiratory burst was modulated by 17β-estradiol. These actions were blocked by the pure ER antagonist ICI 182780 indicating that response is, in part, mediated via ERα. In summary, estrogen receptors are expressed in channel catfish leukocytes and participate in the regulation of the immune response. This is the first time leukocyte lineage expression has been reported in teleost cell lines.

Role of dietary bioactive natural products in estrogen receptor-positive breast cancer

PubMed Central

Bak, Min Ji; Das Gupta, Soumyasri; Wahler, Joseph; Suh, Nanjoo

2016-01-01

Estrogen receptor (ER)-positive breast cancer, including luminal-A and -B, is the most common type of breast cancer. Extended exposure to estrogen is associated with an increased risk of breast cancer. Both ER-dependent and ER-independent mechanisms have been implicated in estrogen-mediated carcinogenesis. The ER-dependent pathway involves cell growth and proliferation triggered by the binding of estrogen to the ER. The ER-independent mechanisms depend on the metabolism of estrogen to generate genotoxic metabolites, free radicals and reactive oxygen species to induce breast cancer. A better understanding of the mechanisms that drive ER-positive breast cancer will help optimize targeted approaches to prevent or treat breast cancer. A growing emphasis is being placed on alternative medicine and dietary approaches toward the prevention and treatment of breast cancer. Many natural products and bioactive compounds found in foods have been shown to inhibit breast carcinogenesis via inhibition of estrogen induced oxidative stress as well as ER signaling. This review summarizes the role of bioactive natural products that are involved in the prevention and treatment of estrogen-related and ER-positive breast cancer. PMID:27016037

Purple sweet potato color attenuates domoic acid-induced cognitive deficits by promoting estrogen receptor-α-mediated mitochondrial biogenesis signaling in mice.

PubMed

Lu, Jun; Wu, Dong-Mei; Zheng, Yuan-Lin; Hu, Bin; Cheng, Wei; Zhang, Zi-Feng

2012-02-01

Recent findings suggest that endoplasmic reticulum stress may be involved in the pathogenesis of domoic acid-induced neurodegeneration. Purple sweet potato color, a class of naturally occurring anthocyanins, has beneficial health and biological effects. Recent studies have also shown that anthocyanins have estrogenic activity and can enhance estrogen receptor-α expression. In this study, we evaluated the effect of purple sweet potato color on cognitive deficits induced by hippocampal mitochondrial dysfunction in domoic acid-treated mice and explored the potential mechanisms underlying this effect. Our results showed that the oral administration of purple sweet potato color to domoic acid-treated mice significantly improved their behavioral performance in a step-through passive avoidance task and a Morris water maze task. These improvements were mediated, at least in part, by a stimulation of estrogen receptor-α-mediated mitochondrial biogenesis signaling and by decreases in the expression of p47phox and gp91phox. Decreases in reactive oxygen species and protein carbonylation were also observed, along with a blockade of the endoplasmic reticulum stress pathway. Furthermore, purple sweet potato color significantly suppressed endoplasmic reticulum stress-induced apoptosis, which prevented neuron loss and restored the expression of memory-related proteins. However, knockdown of estrogen receptor-α using short hairpin RNA only partially blocked the neuroprotective effects of purple sweet potato color in the hippocampus of mice cotreated with purple sweet potato color and domoic acid, indicating that purple sweet potato color acts through multiple pathways. These results suggest that purple sweet potato color could be a possible candidate for the prevention and treatment of cognitive deficits in excitotoxic and other brain disorders. Crown Copyright © 2011. Published by Elsevier Inc. All rights reserved.

[Roles of G protein-coupled estrogen receptor in the male reproductive system].

PubMed

Chen, Kai-hong; Zhang, Xian; Jiang, Xue-wu

2016-02-01

The G protein-coupled estrogen receptor (GPER), also known as G protein-coupled receptor 30 (GPR30), was identified in the recent years as a functional membrane receptor different from the classical nuclear estrogen receptors. This receptor is widely expressed in the cortex, cerebellum, hippocampus, heart, lung, liver, skeletal muscle, and the urogenital system. It is responsible for the mediation of nongenomic effects associated with estrogen and its derivatives, participating in the physiological activities of the body. The present study reviews the molecular structure, subcellular localization, signaling pathways, distribution, and function of GPER in the male reproductive system.

G protein-coupled estrogen receptor (GPER) mediates NSCLC progression induced by 17β-estradiol (E2) and selective agonist G1.

PubMed

Liu, Changyu; Liao, Yongde; Fan, Sheng; Tang, Hexiao; Jiang, Zhixiao; Zhou, Bo; Xiong, Jing; Zhou, Sheng; Zou, Man; Wang, Jianmiao

2015-04-01

Estrogen classically drives lung cancer development via estrogen receptor β (ERβ). However, fulvestrant, an anti-estrogen-based endocrine therapeutic treatment, shows limited effects for non-small cell lung cancer (NSCLC) in phase II clinical trials. G protein-coupled estrogen receptor (GPER), a third estrogen receptor that binds to estrogen, has been found to be activated by fulvestrant, stimulating the progression of breast, endometrial, and ovarian cancers. We here demonstrated that cytoplasm-GPER (cGPER) (80.49 %) and nucleus-GPER (53.05 %) were detected by immunohistochemical analysis in NSCLC samples. cGPER expression was related to stages IIIA-IV, lymph node metastasis, and poorly differentiated NSCLC. Selective agonist G1 and 17β-estradiol (E2) promoted the GPER-mediated proliferation, invasion, and migration of NSCLC cells. Additionally, in vitro administration of E2 and G1 increased the number of tumor nodules, tumor grade, and tumor index in a urethane-induced adenocarcinoma model. Importantly, the pro-tumorigenic effects of GPER induced by E2 were significantly reduced by co-administering the GPER inhibitor G15 and the ERβ inhibitor fulvestrant, as compared to administering fulvestrant alone both in vitro and in vivo. Moreover, the phosphorylation of MAPK and Akt was involved in E2/G1-induced GPER activation. In conclusion, our results indicated that a pro-tumor function of GPER exists that mediated E2-/G1-dependent NSCLC progression and showed better efficiency regarding the co-targeting of GPER and ERβ, providing a rationale for further investigation of anti-estrogen clinical therapy.

ICI 182,780-Regulated Gene Expression in DU145 Prostate Cancer Cells Is Mediated by Estrogen Receptor-β/NFκB Crosstalk1

PubMed Central

Leung, Yuet-Kin; Gao, Ying; Lau, Kin-Mang; Zhang, Xiang; Ho, Shuk-Mei

2006-01-01

Abstract Estrogen receptor (ER)-β is the predominant ER subtype in prostate cancer (PCa). We previously demonstrated that ICI 182,780 (ICI), but not estrogens, exerted dose-dependent growth inhibition on DU145 PCa cells by an ER-β-mediated pathway. Transcriptional profiling detected a greater than three-fold upregulation of seven genes after a 12-hour exposure to 1 µM ICI. Semi-quantitative reverse transcriptase polymerase chain reaction confirmed the upregulation of four genes by ICI: interleukin-12α chain, interleukin-8, embryonic growth/differentiation factor, and RYK tyrosine kinase. Treatment with an ER-β antisense oligonucleotide reduced cellular ER-β mRNA and induced loss of expression of these genes. Sequence analysis revealed the presence of consensus NFκB sites, but not estrogen-responsive elements, in promoters of all four genes. Reporter assay and chromatin immunoprecipitation experiments demonstrated that ICI-induced gene expression could be mediated by crosstalk between ER-α and the NFκB signaling pathway, denoting a novel mechanism of ER-β-mediated ICI action. Therefore, combined therapies targeting ER-β and NFκB signaling may be synergistic as treatment for PCa. PMID:16756716

Rapid Estrogen Receptor-Mediated Mechanisms Determine the Sexually Dimorphic Sensitivity of Ventricular Myocytes to 17β-Estradiol and the Environmental Endocrine Disruptor Bisphenol A

PubMed Central

Belcher, Scott M.; Chen, Yamei; Yan, Sujuan

2012-01-01

Previously we showed that 17β-estradiol (E2) and/or the xenoestrogen bisphenol A (BPA) alter ventricular myocyte Ca2+ handing, resulting in increased cardiac arrhythmias in a female-specific manner. In the present study, the roles of estrogen receptors (ER) in mediating the rapid contractile and arrhythmogenic effects of estrogens were examined. Contractility was used as an index to assess the impact of E2 or BPA on Ca2+ handling in rodent ventricular myocytes. The concentration-response curve for the stimulatory effects of BPA and E2 on female myocyte was inverted-U shaped. Detectable effects for each compound were observed at 10−12 m, and the most efficacious concentrations for each were at 10−9 m. Sensitivity to E2 and BPA was not observed in male myocytes and was abolished in myocytes from ovariectomized females. Analysis using protein-conjugated E2 suggests that these rapid actions are induced by membrane-associated receptors. Analysis using selective ER agonists and antagonists and a genetic ERβ knockout mouse model showed that ERα and ERβ have opposing actions in myocytes and that the balance between ERβ and ERα signaling is the prime regulator of the sex-specific sensitivity toward estrogens. The response of female myocytes to E2 and BPA is dominated by the stimulatory ERβ-mediated signaling, and the absence of BPA and E2 responsiveness in males is due to a counterbalancing-suppressive action of ERα. We conclude that the sex-specific sensitivity of myocytes to estrogens and the rapid arrhythmogenic effects of BPA and estradiol in the female heart are regulated by the balance between ERα and ERβ signaling. PMID:22166976

Channel catfish (Ictalurus punctatus) leukocytes express estrogen receptor isoforms ERα and ERβ2 and are functionally modulated by estrogens.

PubMed

Iwanowicz, Luke R; Stafford, James L; Patiño, Reynaldo; Bengten, Eva; Miller, Norman W; Blazer, Vicki S

2014-09-01

Estrogens are recognized as modulators of immune responses in mammals and teleosts. While it is known that the effects of estrogens are mediated via leukocyte-specific estrogen receptors (ERs) in humans and mice, leucocyte-specific estrogen receptor expression and the effects of estrogens on this cell population is less explored and poorly understood in teleosts. Here in, we verify that channel catfish (Ictalurus punctaus) leukocytes express ERα and ERβ2. Transcripts of these isoforms were detected in tissue-associated leukocyte populations by PCR, but ERβ2 was rarely detected in PBLs. Expression of these receptors was temporally regulated in PBLs following polyclonal activation by concanavalin A, lipopolysaccharide or alloantigen based on evaluation by quantitative and end-point PCR. Examination of long-term leukocyte cell lines demonstrated that these receptors are differentially expressed depending on leukocyte lineage and phenotype. Expression of ERs was also temporally dynamic in some leukocyte lineages and may reflect stage of cell maturity. Estrogens affect the responsiveness of channel catfish peripheral blood leukocytes (PBLs) to mitogens in vitro. Similarly, bactericidal activity and phorbol 12-myristate 13-acetate induced respiratory burst was modulated by 17β-estradiol. These actions were blocked by the pure ER antagonist ICI 182780 indicating that response is, in part, mediated via ERα. In summary, estrogen receptors are expressed in channel catfish leukocytes and participate in the regulation of the immune response. This is the first time leukocyte lineage expression has been reported in teleost cell lines. Published by Elsevier Ltd.

Designer interface peptide grafts target estrogen receptor alpha dimerization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chakraborty, S.; Asare, B.K.; Biswas, P.K., E-mail: pbiswas@tougaloo.edu

The nuclear transcription factor estrogen receptor alpha (ERα), triggered by its cognate ligand estrogen, regulates a variety of cellular signaling events. ERα is expressed in 70% of breast cancers and is a widely validated target for anti-breast cancer drug discovery. Administration of anti-estrogen to block estrogen receptor activation is still a viable anti-breast cancer treatment option but anti-estrogen resistance has been a significant bottle-neck. Dimerization of estrogen receptor is required for ER activation. Blocking ERα dimerization is therefore a complementary and alternative strategy to combat anti-estrogen resistance. Dimer interface peptide “I-box” derived from ER residues 503–518 specifically blocks ER dimerization.more » Recently using a comprehensive molecular simulation we studied the interaction dynamics of ERα LBDs in a homo-dimer. Based on this study, we identified three interface recognition peptide motifs LDKITDT (ERα residues 479–485), LQQQHQRLAQ (residues 497–506), and LSHIRHMSNK (residues 511–520) and reported the suitability of using LQQQHQRLAQ (ER 497–506) as a template to design inhibitors of ERα dimerization. Stability and self-aggregation of peptide based therapeutics poses a significant bottle-neck to proceed further. In this study utilizing peptide grafted to preserve their pharmacophoric recognition motif and assessed their stability and potential to block ERα mediated activity in silico and in vitro. The Grafted peptides blocked ERα mediated cell proliferation and viability of breast cancer cells but did not alter their apoptotic fate. We believe the structural clues identified in this study can be used to identify novel peptidometics and small molecules that specifically target ER dimer interface generating a new breed of anti-cancer agents. - Highlights: • Designer peptide grafts retain core molecular recognition motif during MD simulations. • Designer peptide grafts with Poly-ALA helix form stable

International Union of Basic and Clinical Pharmacology. XCVII. G Protein–Coupled Estrogen Receptor and Its Pharmacologic Modulators

PubMed Central

2015-01-01

Estrogens are critical mediators of multiple and diverse physiologic effects throughout the body in both sexes, including the reproductive, cardiovascular, endocrine, nervous, and immune systems. As such, alterations in estrogen function play important roles in many diseases and pathophysiological conditions (including cancer), exemplified by the lower prevalence of many diseases in premenopausal women. Estrogens mediate their effects through multiple cellular receptors, including the nuclear receptor family (ERα and ERβ) and the G protein–coupled receptor (GPCR) family (GPR30/G protein–coupled estrogen receptor [GPER]). Although both receptor families can initiate rapid cell signaling and transcriptional regulation, the nuclear receptors are traditionally associated with regulating gene expression, whereas GPCRs are recognized as mediating rapid cellular signaling. Estrogen-activated pathways are not only the target of multiple therapeutic agents (e.g., tamoxifen, fulvestrant, raloxifene, and aromatase inhibitors) but are also affected by a plethora of phyto- and xeno-estrogens (e.g., genistein, coumestrol, bisphenol A, dichlorodiphenyltrichloroethane). Because of the existence of multiple estrogen receptors with overlapping ligand specificities, expression patterns, and signaling pathways, the roles of the individual receptors with respect to the diverse array of endogenous and exogenous ligands have been challenging to ascertain. The identification of GPER-selective ligands however has led to a much greater understanding of the roles of this receptor in normal physiology and disease as well as its interactions with the classic estrogen receptors ERα and ERβ and their signaling pathways. In this review, we describe the history and characterization of GPER over the past 15 years focusing on the pharmacology of steroidal and nonsteroidal compounds that have been employed to unravel the biology of this most recently recognized estrogen receptor. PMID

Estrogen receptor alpha deficiency modulates TLR ligand mediated PDC-TREM expression in plasmacytoid dendritic cells in lupus prone mice

PubMed Central

Scott, Jennifer L; Cunningham, Melissa A; Naga, Osama S; Wirth, Jena R; EuDaly, Jackie G; Gilkeson, Gary S

2016-01-01

Female lupus prone NZM2410 estrogen receptor alpha (ERα) deficient mice are protected from renal disease and have prolonged survival compared to wild type (WT) littermates, however the mechanism of protection is unknown. Plasmacytoid dendritic cells (pDCs) and type I interferon (IFN) drive lupus pathogenesis. Estrogen acting via ERα enhances both pDC development and IFN production. The objectives for this study were to determine if ERα modulates pDC function and IFN activity in pre-disease NZM2410 mice as a possible protective mechanism of ERα deficiency in lupus prone mice. We measured the effect of ERα deficiency on spleen pDC frequency, number, maturation, and activation state. ERα deficiency reduced type I IFN activity and the frequency of MHCII+ pDCs in the spleen without altering overall pDC frequency, number, or maturation state. Additionally, ERα deficient NZM2410 mice had a significantly decreased frequency of pDCs expressing PDC-TREM, a modulator of toll-like receptor (TLR) mediated IFN production. After in vitro TLR9 stimulation, ERα deficiency significantly reduced the expression of PDC-TREM on pDCs from both NZM2410 and C57BL/6 mice. Thus, we have identified a significant effect of ERα deficiency on pDCs in pre-disease NZM2410 mice, which may represent a mechanism by which ERα deficiency protects NZM2410 mice from lupus like disease. PMID:26553076

Female Mice Lacking Estrogen Receptor-α in Hypothalamic Proopiomelanocortin (POMC) Neurons Display Enhanced Estrogenic Response on Cortical Bone Mass.

PubMed

Farman, H H; Windahl, S H; Westberg, L; Isaksson, H; Egecioglu, E; Schele, E; Ryberg, H; Jansson, J O; Tuukkanen, J; Koskela, A; Xie, S K; Hahner, L; Zehr, J; Clegg, D J; Lagerquist, M K; Ohlsson, C

2016-08-01

Estrogens are important regulators of bone mass and their effects are mainly mediated via estrogen receptor (ER)α. Central ERα exerts an inhibitory role on bone mass. ERα is highly expressed in the arcuate (ARC) and the ventromedial (VMN) nuclei in the hypothalamus. To test whether ERα in proopiomelanocortin (POMC) neurons, located in ARC, is involved in the regulation of bone mass, we used mice lacking ERα expression specifically in POMC neurons (POMC-ERα(-/-)). Female POMC-ERα(-/-) and control mice were ovariectomized (OVX) and treated with vehicle or estradiol (0.5 μg/d) for 6 weeks. As expected, estradiol treatment increased the cortical bone thickness in femur, the cortical bone mechanical strength in tibia and the trabecular bone volume fraction in both femur and vertebrae in OVX control mice. Importantly, the estrogenic responses were substantially increased in OVX POMC-ERα(-/-) mice compared with the estrogenic responses in OVX control mice for cortical bone thickness (+126 ± 34%, P < .01) and mechanical strength (+193 ± 38%, P < .01). To test whether ERα in VMN is involved in the regulation of bone mass, ERα was silenced using an adeno-associated viral vector. Silencing of ERα in hypothalamic VMN resulted in unchanged bone mass. In conclusion, mice lacking ERα in POMC neurons display enhanced estrogenic response on cortical bone mass and mechanical strength. We propose that the balance between inhibitory effects of central ERα activity in hypothalamic POMC neurons in ARC and stimulatory peripheral ERα-mediated effects in bone determines cortical bone mass in female mice.

International Union of Basic and Clinical Pharmacology. XCVII. G Protein-Coupled Estrogen Receptor and Its Pharmacologic Modulators.

PubMed

Prossnitz, Eric R; Arterburn, Jeffrey B

2015-07-01

Estrogens are critical mediators of multiple and diverse physiologic effects throughout the body in both sexes, including the reproductive, cardiovascular, endocrine, nervous, and immune systems. As such, alterations in estrogen function play important roles in many diseases and pathophysiological conditions (including cancer), exemplified by the lower prevalence of many diseases in premenopausal women. Estrogens mediate their effects through multiple cellular receptors, including the nuclear receptor family (ERα and ERβ) and the G protein-coupled receptor (GPCR) family (GPR30/G protein-coupled estrogen receptor [GPER]). Although both receptor families can initiate rapid cell signaling and transcriptional regulation, the nuclear receptors are traditionally associated with regulating gene expression, whereas GPCRs are recognized as mediating rapid cellular signaling. Estrogen-activated pathways are not only the target of multiple therapeutic agents (e.g., tamoxifen, fulvestrant, raloxifene, and aromatase inhibitors) but are also affected by a plethora of phyto- and xeno-estrogens (e.g., genistein, coumestrol, bisphenol A, dichlorodiphenyltrichloroethane). Because of the existence of multiple estrogen receptors with overlapping ligand specificities, expression patterns, and signaling pathways, the roles of the individual receptors with respect to the diverse array of endogenous and exogenous ligands have been challenging to ascertain. The identification of GPER-selective ligands however has led to a much greater understanding of the roles of this receptor in normal physiology and disease as well as its interactions with the classic estrogen receptors ERα and ERβ and their signaling pathways. In this review, we describe the history and characterization of GPER over the past 15 years focusing on the pharmacology of steroidal and nonsteroidal compounds that have been employed to unravel the biology of this most recently recognized estrogen receptor. Copyright �

Aroclor1254 interferes with estrogen receptor-mediated neuroprotection against beta-amyloid toxicity in cholinergic SN56 cells.

PubMed

Bang, Yeojin; Lim, Juhee; Kim, Sa Suk; Jeong, Hyung Min; Jung, Ki-Kyung; Kang, Il-Hyun; Lee, Kwang-Youl; Choi, Hyun Jin

2011-10-01

Because estrogen plays important neurotrophic and neuroprotective roles in the brain by activating estrogen receptors (ERs), disruption of normal estrogen signaling can leave neurons vulnerable to a variety of insults, including β-amyloid peptide (Aβ). Aroclor1254 (A1254) belongs to the endocrine-disrupting chemical (EDC) polychlorinated biphenyls and has anti-estrogenic properties. In the present study, we evaluated the effect of A1254 on the protective activity of estrogen against Aβ toxicity in differentiated cholinergic SN56 cells. Aged Aβ25-35 causes apoptotic cell death in differentiated SN56 cells, and the cytotoxic evidences are effectively rescued by estrogen. We found that A1254 abolishes the neuroprotective activity of estrogen against Aβ toxicity, and attenuates the suppressive effect of estrogen on Aβ-induced tau phosphorylation and JNK activation. The effects of A1254 on the neuroprotective effects of estrogen in Aβ toxicity are very similar to the effects of the estrogen receptor antagonist ICI182,780. Thus, exposure to EDCs that have anti-estrogenic activity might interfere with normal estrogen-activated neuroprotective signaling events and leave neurons more vulnerable to dangerous stimuli. Our present results provide new understanding of the mechanisms contributing to the harmful effects of EDCs on the function and viability of neurons, and the possible relevance of EDCs in the pathogenesis of neurodegenerative diseases such as Alzheimer's disease. Copyright © 2011 Elsevier B.V. All rights reserved.

Estrogen promotes the brain metastatic colonization of triple negative breast cancer cells via an astrocyte-mediated paracrine mechanism

PubMed Central

Sartorius, Carol A.; Hanna, Colton T.; Gril, Brunilde; Cruz, Hazel; Serkova, Natalie J.; Huber, Kendra M.; Kabos, Peter; Schedin, Troy B.; Borges, Virginia F.; Steeg, Patricia S.; Cittelly, Diana M.

2015-01-01

Brain metastases (BM) are a devastating consequence of breast cancer. BM occur more frequently in patients with estrogen receptor-negative (ER−) breast cancer subtypes; HER2 overexpressing (HER2+) tumors and triple-negative (TN) (ER−, progesterone receptor-negative (PR−) and normal HER2) tumors. Young age is an independent risk factor for development of BM, thus we speculated that higher circulating estrogens in young, pre-menopausal women could exert paracrine effects through the highly estrogen-responsive brain microenvironment. Using a TN experimental metastases model, we demonstrate that ovariectomy decreased the frequency of MRI detectable lesions by 56% as compared to estrogen supplementation, and that the combination of ovariectomy and letrozole further reduced the frequency of large lesions to 14.4% of the estrogen control. Human BM expressed 4.2-48.4% ER+ stromal area, particularly ER+ astrocytes. In vitro, E2-treated astrocytes increased proliferation, migration and invasion of 231BR-EGFP cells in an ER-dependent manner. E2 upregulated EGFR ligands Egf, Ereg, and Tgfa mRNA and protein levels in astrocytes, and activated EGFR in brain metastatic cells. Co-culture of 231BR-EGFP cells with E2-treated astrocytes led to upregulation of the metastatic mediator S100 Calcium-binding protein A4 (S100A4) (1.78-fold, P<0.05). Exogenous EGF increased S100A4 mRNA levels in 231BR-EGFP cells (1.40±0.02 fold, P<0.01 compared to vehicle-control) and an EGFR/HER2 inhibitor blocked this effect, suggesting that S100A4 is a downstream effector of EGFR activation. ShRNA-mediated S100A4 silencing in 231BR-EGFP cells decreased their migration and invasion in response to E2-CM, abolished their increased proliferation in co-cultures with E2-treated astrocytes, and decreased brain metastatic colonization. Thus, S100A4 is one effector of the paracrine action of E2 in brain metastatic cells. These studies provide a novel mechanism by which estrogens, acting through ER

Gene therapy of uterine leiomyomas: adenovirus-mediated expression of dominant negative estrogen receptor inhibits tumor growth in nude mice.

PubMed

Al-Hendy, Ayman; Lee, Eun J; Wang, Hui Q; Copland, John A

2004-11-01

Leiomyomas (fibroids) are common estrogen-dependent uterine tumors with no effective medicinal treatment; hysterectomy is the mainstay of management. This study was undertaken to investigate a potential therapy for leiomyoma; we used a mutated dominant-negative estrogen receptor gene delivered via an adenoviral vector (Ad-ER-DN). Ad-ER-DN transduction, in both human and rat leiomyoma cell lines, induced an increase in both caspase-3 levels and BAX/Bcl-2 ratio with evident apoptosis in the TdT-mediated dUTP nick-end labeling assay. In nude mice, rat leiomyoma cells ex vivo transduced with Ad-ER-DN supported significantly smaller tumors compared with Ad-LacZ-treated cells 5 weeks after implantation. In mice treated by direct intratumor injection into preexisting lesions, Ad-ER-DN caused immediate overall arrest of tumor growth. The Ad-ER-DN-treated tumors demonstrated severely inhibited cell proliferation (BrdU index) and a marked increase in the number of apoptotic cells (TdT-mediated dUTP nick-end labeling index). Dominant-negative estrogen receptor gene therapy may provide a nonsurgical treatment option for women with symptomatic uterine fibroids who want to preserve their uteri.

Estrogen Receptor β Activation Rapidly Modulates Male Sexual Motivation through the Transactivation of Metabotropic Glutamate Receptor 1a

PubMed Central

Seredynski, Aurore L.; Balthazart, Jacques; Ball, Gregory F.

2015-01-01

In addition to the transcriptional activity of their liganded nuclear receptors, estrogens, such as estradiol (E2), modulate cell functions, and consequently physiology and behavior, within minutes through membrane-initiated events. The membrane-associated receptors (mERs) underlying the acute effects of estrogens on behavior have mostly been documented in females where active estrogens are thought to be of ovarian origin. We determined here, by acute intracerebroventricular injections of specific agonists and antagonists, the type(s) of mERs that modulate rapid effects of brain-derived estrogens on sexual motivation in male Japanese quail. Brain aromatase blockade acutely inhibited sexual motivation. Diarylpropionitrile (DPN), an estrogen receptor β (ERβ)-specific agonist, and to a lesser extent 17α-estradiol, possibly acting through ER-X, prevented this effect. In contrast, drugs targeting ERα (PPT and MPP), GPR30 (G1 and G15), and the Gq-mER (STX) did not affect sexual motivation. The mGluR1a antagonist LY367385 significantly inhibited sexual motivation but mGluR2/3 and mGluR5 antagonists were ineffective. LY367385 also blocked the behavioral restoration induced by E2 or DPN, providing functional evidence that ERβ interacts with metabotropic glutamate receptor 1a (mGluR1a) signaling to acutely regulate male sexual motivation. Together these results show that ERβ plays a key role in sexual behavior regulation and the recently uncovered cooperation between mERs and mGluRs is functional in males where it mediates the acute effects of estrogens produced centrally in response to social stimuli. The presence of an ER–mGluR interaction in birds suggests that this mechanism emerged relatively early in vertebrate history and is well conserved. SIGNIFICANCE STATEMENT The membrane-associated receptors underlying the acute effects of estrogens on behavior have mostly been documented in females, where active estrogens are thought to be of ovarian origin. Using acute

Estrogen Receptor β Activation Rapidly Modulates Male Sexual Motivation through the Transactivation of Metabotropic Glutamate Receptor 1a.

PubMed

Seredynski, Aurore L; Balthazart, Jacques; Ball, Gregory F; Cornil, Charlotte A

2015-09-23

In addition to the transcriptional activity of their liganded nuclear receptors, estrogens, such as estradiol (E2), modulate cell functions, and consequently physiology and behavior, within minutes through membrane-initiated events. The membrane-associated receptors (mERs) underlying the acute effects of estrogens on behavior have mostly been documented in females where active estrogens are thought to be of ovarian origin. We determined here, by acute intracerebroventricular injections of specific agonists and antagonists, the type(s) of mERs that modulate rapid effects of brain-derived estrogens on sexual motivation in male Japanese quail. Brain aromatase blockade acutely inhibited sexual motivation. Diarylpropionitrile (DPN), an estrogen receptor β (ERβ)-specific agonist, and to a lesser extent 17α-estradiol, possibly acting through ER-X, prevented this effect. In contrast, drugs targeting ERα (PPT and MPP), GPR30 (G1 and G15), and the Gq-mER (STX) did not affect sexual motivation. The mGluR1a antagonist LY367385 significantly inhibited sexual motivation but mGluR2/3 and mGluR5 antagonists were ineffective. LY367385 also blocked the behavioral restoration induced by E2 or DPN, providing functional evidence that ERβ interacts with metabotropic glutamate receptor 1a (mGluR1a) signaling to acutely regulate male sexual motivation. Together these results show that ERβ plays a key role in sexual behavior regulation and the recently uncovered cooperation between mERs and mGluRs is functional in males where it mediates the acute effects of estrogens produced centrally in response to social stimuli. The presence of an ER-mGluR interaction in birds suggests that this mechanism emerged relatively early in vertebrate history and is well conserved. Significance statement: The membrane-associated receptors underlying the acute effects of estrogens on behavior have mostly been documented in females, where active estrogens are thought to be of ovarian origin. Using acute

The anticancer estrogen receptor antagonist tamoxifen impairs consolidation of inhibitory avoidance memory through estrogen receptor alpha.

PubMed

Lichtenfels, Martina; Dornelles, Arethuza da Silva; Petry, Fernanda Dos Santos; Blank, Martina; de Farias, Caroline Brunetto; Roesler, Rafael; Schwartsmann, Gilberto

2017-11-01

Over two-thirds of women with breast cancer have positive tumors for hormone receptors, and these patients undergo treatment with endocrine therapy, tamoxifen being the most widely used agent. Despite being very effective in breast cancer treatment, tamoxifen is associated with side effects that include cognitive impairments. However, the specific aspects and mechanisms underlying these impairments remain to be characterized. Here, we have investigated the effects of tamoxifen and interaction with estrogen receptors on formation of memory for inhibitory avoidance conditioning in female rats. In the first experiment, Wistar female rats received a single oral dose of tamoxifen (1, 3, or 10 mg/kg) or saline by gavage immediately after training and were tested for memory consolidation 24 h after training. In the second experiment, rats received a single dose of 1 mg/kg tamoxifen or saline by gavage 3 h after training and were tested 24 h after training for memory consolidation. In the third experiment, rats received a subcutaneous injection with estrogen receptor α agonist or estrogen receptor beta agonist 30 min before the training. After training, rats received a single oral dose of tamoxifen 1 mg/kg or saline and were tested 24 h after training. In the fourth experiment, rats were trained and tested 24 h later. Immediately after test, rats received a single dose of tamoxifen (1 mg/kg) or saline by gavage and were given four additional daily test trials followed by a re-instatement. Tamoxifen at 1 mg/kg impaired memory consolidation when given immediately after training and the estrogen receptor alpha agonist improved the tamoxifen-related memory impairment. Moreover, tamoxifen impairs memory consolidation of the test. These findings indicate that estrogen receptors regulate the early phase of memory consolidation and the effects of tamoxifen on memory consolidation.

Melanocortin 4 receptor is not required for estrogenic regulations on energy homeostasis and reproduction

USDA-ARS?s Scientific Manuscript database

Brain estrogen receptor-a (ERa) is essential for estrogenic regulation of energy homeostasis and reproduction. We previously showed that ERa expressed by pro-opiomelanocortin (POMC) neurons mediates estrogen's effects on food intake, body weight, negative regulation of hypothalamic–pituitary–gonadal...

Expression and functional roles of G-protein-coupled estrogen receptor (GPER) in human eosinophils.

PubMed

Tamaki, Mami; Konno, Yasunori; Kobayashi, Yoshiki; Takeda, Masahide; Itoga, Masamichi; Moritoki, Yuki; Oyamada, Hajime; Kayaba, Hiroyuki; Chihara, Junichi; Ueki, Shigeharu

2014-07-01

Sexual dimorphism in asthma links the estrogen and allergic immune responses. The function of estrogen was classically believed to be mediated through its nuclear receptors, i.e., estrogen receptors (ERs). However, recent studies established the important roles of G-protein-coupled estrogen receptor (GPER/GPR30) as a novel membrane receptor for estrogen. To date, the role of GPER in allergic inflammation is poorly understood. The purpose of this study was to examine whether GPER might affect the functions of eosinophils, which play an important role in the pathogenesis of asthma. Here, we demonstrated that GPER was expressed in purified human peripheral blood eosinophils both at the mRNA and protein levels. Although GPER agonist G-1 did not induce eosinophil chemotaxis or chemokinesis, preincubation with G-1 enhanced eotaxin (CCL11)-directed eosinophil chemotaxis. G-1 inhibited eosinophil spontaneous apoptosis and caspase-3 activities. The anti-apoptotic effect was not affected by the cAMP-phospodiesterase inhibitor rolipram or phosphoinositide 3-kinase inhibitors. In contrast to resting eosinophils, G-1 induced apoptosis and increased caspase-3 activities when eosinophils were co-stimulated with IL-5. No effect of G-1 was observed on eosinophil degranulation in terms of release of eosinophil-derived neurotoxin (EDN). The current study indicates the functional capacities of GPER on human eosinophils and also provides the previously unrecognized mechanisms of interaction between estrogen and allergic inflammation. Copyright © 2014 Elsevier B.V. All rights reserved.

Estrogen receptor ligands: a patent review update.

PubMed

Paterni, Ilaria; Bertini, Simone; Granchi, Carlotta; Macchia, Marco; Minutolo, Filippo

2013-10-01

The role of estrogens is mostly mediated by two nuclear receptors (ERα and ERβ) and a membrane-associated G-protein (GPR30 or GPER), and it is not limited to reproduction, but it extends to the skeletal, cardiovascular and central nervous systems. Various pathologies such as cancer, inflammatory, neurodegenerative and metabolic diseases are often associated with dysfunctions of the estrogenic system. Therapeutic interventions by agents that affect the estrogenic signaling pathway might be useful in the treatment of many dissimilar diseases. The massive chemodiversity of ER ligands, limited to patented small molecules, is herein reviewed. The reported compounds are classified on the basis of their chemical structures. Non-steroidal derivatives, which mostly consist of diphenolic compounds, are further segregated into chemical classes based on their central scaffold. Estrogens have been used for almost a century and their earlier applications have concerned interventions in the female reproductive functions, as well as the treatment of some estrogen-dependent cancers and osteoporosis. Since the discovery of ERβ in 1996, the patent literature has started to pay a progressively increasing attention to this newer receptor subtype, which holds promise as a target for new indications, most of which still need to be clinically validated.

G protein-coupled estrogen receptor (GPER) expression in normal and abnormal endometrium.

PubMed

Plante, Beth J; Lessey, Bruce A; Taylor, Robert N; Wang, Wei; Bagchi, Milan K; Yuan, Lingwen; Scotchie, Jessica; Fritz, Marc A; Young, Steven L

2012-07-01

Rapid estrogen effects are mediated by membrane receptors, and evidence suggests a role for both a membrane-associated form of estrogen receptor alpha (ESR1; ERα) and G-protein coupled receptor 30 (GPER; GPR30). Considering estrogen's importance in endometrial physiology and endometriosis pathophysiology, we hypothesized that GPER could be involved in both cyclic changes in endometrial estrogen action and that aberrant expression might be seen in the eutopic endometrium of women with endometriosis. Using real-time reverse transcriptase-polymerase chain reaction (RT-PCR) and immunohistochemical analysis of normal endometrium, endometrial samples demonstrated cycle-regulated expression of GPER, with maximal expression in the proliferative phase. Eutopic and ectopic endometrium from women with endometriosis overexpressed GPER as compared to eutopic endometrium of normal participants. Ishikawa cells, an adenocarcinoma cell line, expressed GPER, with increased expression upon treatment with estrogen or an ESR1 agonist, but not with a GPER-specific agonist. Decreased expression was seen in Ishikawa cells stably transfected with progesterone receptor A. Together, these data suggest that normal endometrial GPER expression is cyclic and regulated by nuclear estrogen and progesterone receptors, while expression is dysregulated in endometriosis.

Increased anxiety and synaptic plasticity in estrogen receptor -deficient mice

NASA Astrophysics Data System (ADS)

Krel, Wojciech; Dupont, Sonia; Krust, Andrée; Chambon, Pierre; Chapman, Paul F.

2001-10-01

Estrogens are powerful modulators of neuronal physiology and in humans may affect a broad range of functions, including reproductive, emotional, and cognitive behaviors. We studied the contribution of estrogen receptors (ERs) in modulation of emotional processes and analyzed the effects of deleting ER or ER in mice. Behavior consistent with increased anxiety was observed principally in ER mutant females and was associated with a reduced threshold for the induction of synaptic plasticity in the basolateral amygdala. Local increase of 5-hydroxytryptamine 1a receptor expression inmedial amygdala may contribute to these changes. Our data show that, particularly in females, there is an important role for ERβ-mediated estrogen signaling in the processing of emotional behavior.

Melanocortin 4 receptor is not required for estrogenic regulations on energy homeostasis and reproduction.

PubMed

Xu, Pingwen; Zhu, Liangru; Saito, Kenji; Yang, Yongjie; Wang, Chunmei; He, Yanlin; Yan, Xiaofeng; Hyseni, Ilirjana; Tong, Qingchun; Xu, Yong

2017-05-01

Brain estrogen receptor-α (ERα) is essential for estrogenic regulation of energy homeostasis and reproduction. We previously showed that ERα expressed by pro-opiomelanocortin (POMC) neurons mediates estrogen's effects on food intake, body weight, negative regulation of hypothalamic-pituitary-gonadal axis (HPG axis) and fertility. We report here that global deletion of a key downstream receptor for POMC peptide, the melanocortin 4 receptor (MC4R), did not affect normal negative feedback regulation of estrogen on the HPG axis, estrous cyclicity and female fertility. Furthermore, loss of the MC4R did not influence estrogenic regulation on food intake and body weight. These results indicate that the MC4R is not required for estrogen's effects on metabolic and reproductive functions. Copyright © 2016 Elsevier Inc. All rights reserved.

GPER1 mediates estrogen-induced neuroprotection against oxygen-glucose deprivation in the primary hippocampal neurons.

PubMed

Zhao, Tian-Zhi; Shi, Fei; Hu, Jun; He, Shi-Ming; Ding, Qian; Ma, Lian-Ting

2016-07-22

It is well-known that the neuroprotective effects of estrogen have potential in the prevention and amelioration of ischemic and degenerative neurological disorders, while the underlying mechanisms for estrogen actions are undefined. As an important mediator for the non-genomic functions of estrogen, GPER1 (G Protein-coupled Estrogen Receptor 1) has been suggested to involve in the beneficial roles of estrogen in neural cells. Here our studies on primary hippocampal neurons have focused on GPER1 in an in vitro model of ischemia using oxygen-glucose deprivation (OGD). GPER1 expression in the primary hippocampal neurons was stimulated by the OGD treatments. Both E2 (estradiol) and E2-BSA (membrane impermeable estradiol by covalent conjugation of bovine serum albumin) attenuated OGD-induced cell death in primary cultures of hippocampal neurons. Importantly, this membrane-mediated estrogen function requires GPER1 protein. Knocking down of GPER1 diminished, while overexpression of GPER1 potentiated, the protective roles of E2/E2-BSA following OGD. Additionally, the downstream mechanisms employed by membrane-associated estrogen signaling were found to include PI3K/Akt-dependent Ask1 inhibition in the primary hippocampal neurons. Overall, these research results could enhance our understanding of the neuroprotective actions for estrogen, and provide a new therapeutic target for improving stroke outcome and ameliorating degenerative neurological diseases. Copyright © 2016 IBRO. Published by Elsevier Ltd. All rights reserved.

Expression pattern and signalling pathways in neutrophil like HL-60 cells after treatment with estrogen receptor selective ligands.

PubMed

Blesson, Chellakkan Selvanesan; Sahlin, Lena

2012-09-25

Estrogens play a role in the regulation of genes associated with inflammation and immunity in neutrophils. Estrogen signalling is mediated by estrogen receptor (ER)α, ERβ, and G-protein-coupled estrogen receptor-1 (GPER). The mechanisms by which estrogen regulate genes in neutrophils are poorly understood. Our aim was to identify the presence of ERs and to characterize estrogen responsive genes in terminally differentiated neutrophil like HL-60 (nHL-60) cells using estradiol and selective ER agonists. ERs were identified by Western blotting and immunocytochemistry. Microarray technique was used to screen for differentially expressed genes and the selected genes were verified by quantitative PCR. We show the presence of functional ERα, ERβ and GPER. Microarray analysis showed the presence of genes that are uniquely regulated by a single ligand and also genes that are regulated by multiple ligands. We conclude that ERs are functionally active in nHL-60 cells regulating genes involved in key physiological functions. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

Identification of the G protein-coupled estrogen receptor (GPER) in human prostate: expression site of the estrogen receptor in the benign and neoplastic gland.

PubMed

Rago, V; Romeo, F; Giordano, F; Ferraro, A; Carpino, A

2016-01-01

Estrogens are involved in growth, differentiation and pathogenesis of human prostate through the mediation of the classical estrogen receptors ERα and ERβ. The G protein-coupled estrogen receptor (GPER) is a 'novel' mediator of estrogen signaling which has been recently recognized in some human reproductive tissues, but its expression in the prostate gland is still unknown. Here, we investigated GPER in benign (from 5 patients) and neoplastic prostatic tissues (from 50 patients) by immunohistochemical analysis and Western blotting. Normal areas of benign prostates revealed a strong GPER immunoreactivity in the basal epithelial cells while luminal epithelial cells were unreactive and stromal cells were weakly immunostained. GPER was also immunolocalized in adenocarcinoma samples but the immunoreactivity of tumoral areas decreased from Gleason pattern 2 to Gleason pattern 4. Furthermore, a strong GPER immunostaining was also revealed in cells of pre-neoplastic lesions (high-grade prostatic intra-epithelial neoplasia). Western blot analysis of benign and tumor protein extracts showed the presence of a ~42 kDa band, consistent with the GPER molecular weight. An increase in both pAkt and p cAMP-response-binding protein (pCREB) levels was also observed in poorly differentiated PCa samples. Finally, this work identified GPER in the epithelial basal cells of benign human prostate, with a different localization with respect to the classical estrogen receptors. Furthermore, the expression of GPER in prostatic adenocarcinoma cells was also observed but with a modulation of the immunoreactivity according to tumor cell arrangements. © 2015 American Society of Andrology and European Academy of Andrology.

Estrogenic Activity of Hyperforin in MCF-7 Human Breast Cancer Cells Transfected with Estrogen Receptor.

PubMed

Kwon, Joseph; Oh, Kyung Seo; Cho, Se-Young; Bang, Mi Ae; Kim, Hwan Seon; Vaidya, Bipin; Kim, Duwoon

2016-11-01

Hyperforin, a major active compound of St. John's wort extract, affects estrogenic activity. In this study, the compound evoked estrogen response element-dependent luciferase activity and cell proliferation in MCF-7 cells. Hyperforin-induced cell proliferation was significantly inhibited by the estrogen receptor antagonist ICI 182,780. These results suggested that hyperforin had estrogenic and cell proliferation activities, which were stimulated via the estrogen receptor. Compared to 17 β -estradiol, hyperforin showed significantly lower estrogenic activity and cell proliferation. The mechanism underlying the estrogenic activity of hyperforin was unknown, therefore, in this study, for the first time, the expression and post-translational modification of proteins were determined and compared among control, 17 β -estradiol-treated, and hyperforin-treated cells using proteomic techniques. A total of 453 proteins were identified, of which 282 proteins were significantly modulated in hyperforin-treated cells compared to 17 β -estradiol-treated cells. Ingenuity pathway analysis also demonstrated that hyperforin treatment induced less cell proliferation than 17 β -estradiol by downregulating estrogen receptor 1. Protein network analysis showed that cell proliferation was regulated mainly by cyclin D1 and extracellular signal-regulated kinases. In conclusion, although, hyperforin exhibited lower estrogenic activity than 17 β -estradiol, the compound induced lower levels of cancer cell proliferation in vitro . Georg Thieme Verlag KG Stuttgart · New York.

Estrogen modulates sexually dimorphic contextual fear extinction in rats through estrogen receptor beta.

PubMed

Chang, Yao-Ju; Yang, Chih-Hao; Liang, Ying-Ching; Yeh, Che-Ming; Huang, Chiung-Chun; Hsu, Kuei-Sen

2009-11-01

Females and males are different in brain and behavior. These sex differences occur early during development due to a combination of genetic and hormonal factors and continue throughout the lifespan. Previous studies revealed that male rats exhibited significantly higher levels of contextual fear memory than female rats. However, it remains unknown whether a sex difference exists in the contextual fear extinction. To address this issue, male, normally cycling female, and ovariectomized (OVX) female Sprague-Dawley rats were subjected to contextual fear conditioning and extinction trials. Here we report that although male rats exhibited higher levels of freezing than cycling female rats after contextual fear conditioning, female rats subjected to conditioning in the proestrus and estrus stage exhibited an enhancement of fear extinction than male rats. An estrogen receptor (ER) beta agonist diarylpropionitrile but not an ERalpha agonist propyl-pyrazole-triol administration also enhanced extinction of contextual fear in OVX female rats, suggesting that estrogen-mediated facilitation of extinction involves the activation of ERbeta. Intrahippocampal injection of estradiol or diarylpropionitrile before extinction training in OVX female rats remarkably reduced the levels of freezing response during extinction trials. In addition, the locomotion or anxiety state of female rats does not vary across the ovarian cycle. These results reveal a crucial role for estrogen in mediating sexually dimorphic contextual fear extinction, and that estrogen-mediated enhancement of fear extinction involves the activation of ERbeta.

G Protein-Coupled Estrogen Receptor (GPER) Expression in Normal and Abnormal Endometrium

PubMed Central

Lessey, Bruce A.; Taylor, Robert N.; Wang, Wei; Bagchi, Milan K.; Yuan, Lingwen; Scotchie, Jessica; Fritz, Marc A.; Young, Steven L.

2012-01-01

Rapid estrogen effects are mediated by membrane receptors, and evidence suggests a role for both a membrane-associated form of estrogen receptor alpha (ESR1; ERα) and G-protein coupled receptor 30 (GPER; GPR30). Considering estrogen’s importance in endometrial physiology and endometriosis pathophysiology, we hypothesized that GPER could be involved in both cyclic changes in endometrial estrogen action and that aberrant expression might be seen in the eutopic endometrium of women with endometriosis. Using real-time reverse transcriptase–polymerase chain reaction (RT-PCR) and immunohistochemical analysis of normal endometrium, endometrial samples demonstrated cycle-regulated expression of GPER, with maximal expression in the proliferative phase. Eutopic and ectopic endometrium from women with endometriosis overexpressed GPER as compared to eutopic endometrium of normal participants. Ishikawa cells, an adenocarcinoma cell line, expressed GPER, with increased expression upon treatment with estrogen or an ESR1 agonist, but not with a GPER-specific agonist. Decreased expression was seen in Ishikawa cells stably transfected with progesterone receptor A. Together, these data suggest that normal endometrial GPER expression is cyclic and regulated by nuclear estrogen and progesterone receptors, while expression is dysregulated in endometriosis. PMID:22378861

17β-Estradiol and/or estrogen receptor alpha signaling blocks protein phosphatase 1 mediated ISO induced cardiac hypertrophy.

PubMed

Fang, Hsin-Yuan; Hung, Meng-Yu; Lin, Yueh-Min; Pandey, Sudhir; Chang, Chia-Chien; Lin, Kuan-Ho; Shen, Chia-Yao; Viswanadha, Vijaya Padma; Kuo, Wei-Wen; Huang, Chih-Yang

2018-01-01

Earlier studies have shown that estrogen possess protective function against the development of pathological cardiac hypertrophy. However, the molecular mechanisms of estrogens (E2) protective effect are poorly understood. Additionally, abnormal activation of β-adrenergic signaling have been implicated in the development of pathological cardiac remodeling. However, the role of serine/threonine protein phosphatase 1 (PP1) in pathological cardiac remodeling under the influence of β-adrenergic signaling have been sparsely investigated. In this study, we assessed the downstream effects of abnormal activation of PP1 upon isoproterenol (ISO) induced pathological cardiac changes. We found that pre-treatment of 17β-estradiol (E2), tet-on estrogen receptor-α, or both significantly inhibited ISO-induced increase in cell size, hypertrophy marker gene expression and cytosolic calcium accumulation in H9c2 cells. Additionally, treatment with estrogen receptor inhibitor (ICI) reversed those effects, implicating role of E2 in inhibiting pathological cardiac remodeling. However, specific inhibition of ERα using melatonin, reduced ISO-induced PP1c expression and enhanced the level of ser-16 phosphorylated phospholamban (PLB), responsible for regulation of sarcoplasmic reticulum Ca2+-ATPase (SERCA) activity. Furthermore, hypertrophic effect caused by overexpression of PP1cα was reduced by treatment with specific inhibitor of ERα. Collectively, we found that estrogen and estrogen receptor-α have protective effect against pathological cardiac changes by suppressing PP1 expression and its downstream signaling pathway, which further needs to be elucidated.

Sex differences in opioid analgesia and addiction: interactions among opioid receptors and estrogen receptors

PubMed Central

2013-01-01

Opioids are widely used as the pain reliever and also notorious for being addictive drugs. Sex differences in the opioid analgesia and addiction have been reported and investigated in human subjects and animal models. Yet, the molecular mechanism underlying the differences between males and females is still unclear. Here, we reviewed the literature describing the sex differences in analgesic responses and addiction liabilities to clinically relevant opioids. The reported interactions among opioids, estrogens, opioid receptors, and estrogen receptors are also evaluated. We postulate that the sex differences partly originated from the crosstalk among the estrogen and opioid receptors when stimulated by the exogenous opioids, possibly through common secondary messengers and the downstream gene transcriptional regulators. PMID:24010861

G Protein-coupled Estrogen Receptor Protects from Atherosclerosis

PubMed Central

Meyer, Matthias R.; Fredette, Natalie C.; Howard, Tamara A.; Hu, Chelin; Ramesh, Chinnasamy; Daniel, Christoph; Amann, Kerstin; Arterburn, Jeffrey B.; Barton, Matthias; Prossnitz, Eric R.

2014-01-01

Coronary atherosclerosis and myocardial infarction in postmenopausal women have been linked to inflammation and reduced nitric oxide (NO) formation. Natural estrogen exerts protective effects on both processes, yet also displays uterotrophic activity. Here, we used genetic and pharmacologic approaches to investigate the role of the G protein-coupled estrogen receptor (GPER) in atherosclerosis. In ovary-intact mice, deletion of gper increased atherosclerosis progression, total and LDL cholesterol levels and inflammation while reducing vascular NO bioactivity, effects that were in some cases aggravated by surgical menopause. In human endothelial cells, GPER was expressed on intracellular membranes and mediated eNOS activation and NO formation, partially accounting for estrogen-mediated effects. Chronic treatment with G-1, a synthetic, highly selective small molecule agonist of GPER, reduced postmenopausal atherosclerosis and inflammation without uterotrophic effects. In summary, this study reveals an atheroprotective function of GPER and introduces selective GPER activation as a novel therapeutic approach to inhibit postmenopausal atherosclerosis and inflammation in the absence of uterotrophic activity. PMID:25532911

The role of estrogens and estrogen receptor signaling pathways in cancer and infertility: the case of schistosomes.

PubMed

Botelho, Mónica C; Alves, Helena; Barros, Alberto; Rinaldi, Gabriel; Brindley, Paul J; Sousa, Mário

2015-06-01

Schistosoma haematobium, a parasitic flatworm that infects more than 100 million people, mostly in the developing world, is the causative agent of urogenital schistosomiasis, and is associated with a high incidence of squamous cell carcinoma (SCC) of the bladder. Schistosomiasis haematobia also appears to negatively influence fertility, and is particularly associated with female infertility. Given that estrogens and estrogen receptors are key players in human reproduction, we speculate that schistosome estrogen-like molecules may contribute to infertility through hormonal imbalances. Here, we review recent findings on the role of estrogens and estrogen receptors on both carcinogenesis and infertility associated with urogenital schistosomiasis and discuss the basic hormonal mechanisms that might be common in cancer and infertility. Copyright © 2015 Elsevier Ltd. All rights reserved.

Identifying a Mechanism for Crosstalk Between the Estrogen and Glucocorticoid Receptors | Center for Cancer Research

Cancer.gov

Estrogen has long been known to play important roles in the development and progression of breast cancer. Its receptor (ER), a member of the steroid receptor family, binds to estrogen response elements (EREs) in DNA and regulates gene transcription. More recently, another steroid receptor family member, the glucocorticoid receptor (GR), has been implicated in breast cancer

G protein-coupled estrogen receptor 1 (GPER1)/GPR30 increases ERK1/2 activity through PDZ motif-dependent and -independent mechanisms.

PubMed

Gonzalez de Valdivia, Ernesto; Broselid, Stefan; Kahn, Robin; Olde, Björn; Leeb-Lundberg, L M Fredrik

2017-06-16

G protein-coupled receptor 30 (GPR30), also called G protein-coupled estrogen receptor 1 (GPER1), is thought to play important roles in breast cancer and cardiometabolic regulation, but many questions remain about ligand activation, effector coupling, and subcellular localization. We showed recently that GPR30 interacts through the C-terminal type I PDZ motif with SAP97 and protein kinase A (PKA)-anchoring protein (AKAP) 5, which anchor the receptor in the plasma membrane and mediate an apparently constitutive decrease in cAMP production independently of G i/o Here, we show that GPR30 also constitutively increases ERK1/2 activity. Removing the receptor PDZ motif or knocking down specifically AKAP5 inhibited the increase, showing that this increase also requires the PDZ interaction. However, the increase was inhibited by pertussis toxin as well as by wortmannin but not by AG1478, indicating that G i/o and phosphoinositide 3-kinase (PI3K) mediate the increase independently of epidermal growth factor receptor transactivation. FK506 and okadaic acid also inhibited the increase, implying that a protein phosphatase is involved. The proposed GPR30 agonist G-1 also increased ERK1/2 activity, but this increase was only observed at a level of receptor expression below that required for the constitutive increase. Furthermore, deleting the PDZ motif did not inhibit the G-1-stimulated increase. Based on these results, we propose that GPR30 increases ERK1/2 activity via two G i/o -mediated mechanisms, a PDZ-dependent, apparently constitutive mechanism and a PDZ-independent G-1-stimulated mechanism. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

Ketamine and ketamine metabolites as novel estrogen receptor ligands: Induction of cytochrome P450 and AMPA glutamate receptor gene expression.

PubMed

Ho, Ming-Fen; Correia, Cristina; Ingle, James N; Kaddurah-Daouk, Rima; Wang, Liewei; Kaufmann, Scott H; Weinshilboum, Richard M

2018-04-03

Major depressive disorder (MDD) is the most common psychiatric illness worldwide, and it displays a striking sex-dependent difference in incidence, with two thirds of MDD patients being women. Ketamine treatment can produce rapid antidepressant effects in MDD patients, effects that are mediated-at least partially-through glutamatergic neurotransmission. Two active metabolites of ketamine, (2R,6R)-hydroxynorketamine (HNK) and (2S,6S)-HNK, also appear to play a key role in ketamine's rapid antidepressant effects through the activation of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) glutamate receptors. In the present study, we demonstrated that estrogen plus ketamine or estrogen plus active ketamine metabolites displayed additive effects on the induction of the expression of AMPA receptor subunits. In parallel, the expression of estrogen receptor alpha (ERα) was also significantly upregulated. Even more striking, radioligand binding assays demonstrated that [ 3 H]-ketamine can directly bind to ERα (K D : 344.5 ± 13 nM). Furthermore, ketamine and its (2R,6R)-HNK and (2S,6S)-HNK metabolites displayed similar affinity for ERα (IC 50 : 2.31 ± 0.1, 3.40 ± 0.2, and 3.53 ± 0.2 µM, respectively) as determined by [ 3 H]-ketamine displacement assays. Finally, induction of AMPA receptors by either estrogens or ketamine and its metabolites was lost when ERα was knocked down or silenced pharmacologically. These results suggest a positive feedback loop by which estrogens can augment the effects of ketamine and its (2R,6R)-HNK and (2S,6S)-HNK metabolites on the ERα-induced transcription of CYP2A6 and CYP2B6, estrogen inducible enzymes that catalyze ketamine's biotransformation to form the two active metabolites. These observations provide novel insight into ketamine's molecular mechanism(s) of action and have potential implications for the treatment of MDD. Copyright © 2018 Elsevier Inc. All rights reserved.

Estrogen receptor beta in prostate cancer: friend or foe?

PubMed

Nelson, Adam W; Tilley, Wayne D; Neal, David E; Carroll, Jason S

2014-08-01

Prostate cancer is the commonest, non-cutaneous cancer in men. At present, there is no cure for the advanced, castration-resistant form of the disease. Estrogen has been shown to be important in prostate carcinogenesis, with evidence resulting from epidemiological, cancer cell line, human tissue and animal studies. The prostate expresses both estrogen receptor alpha (ERA) and estrogen receptor beta (ERB). Most evidence suggests that ERA mediates the harmful effects of estrogen in the prostate, whereas ERB is tumour suppressive, but trials of ERB-selective agents have not translated into improved clinical outcomes. The role of ERB in the prostate remains unclear and there is increasing evidence that isoforms of ERB may be oncogenic. Detailed study of ERB and ERB isoforms in the prostate is required to establish their cell-specific roles, in order to determine if therapies can be directed towards ERB-dependent pathways. In this review, we summarise evidence on the role of ERB in prostate cancer and highlight areas for future research. © 2014 Society for Endocrinology.

Estrogen receptor α dependent regulation of estrogen related receptor β and its role in cell cycle in breast cancer.

PubMed

Madhu Krishna, B; Chaudhary, Sanjib; Mishra, Dipti Ranjan; Naik, Sanoj K; Suklabaidya, S; Adhya, A K; Mishra, Sandip K

2018-05-30

Breast cancer (BC) is highly heterogeneous with ~ 60-70% of estrogen receptor positive BC patient's response to anti-hormone therapy. Estrogen receptors (ERs) play an important role in breast cancer progression and treatment. Estrogen related receptors (ERRs) are a group of nuclear receptors which belong to orphan nuclear receptors, which have sequence homology with ERs and share target genes. Here, we investigated the possible role and clinicopathological importance of ERRβ in breast cancer. Estrogen related receptor β (ERRβ) expression was examined using tissue microarray slides (TMA) of Breast Carcinoma patients with adjacent normal by immunohistochemistry and in breast cancer cell lines. In order to investigate whether ERRβ is a direct target of ERα, we investigated the expression of ERRβ in short hairpin ribonucleic acid knockdown of ERα breast cancer cells by western blot, qRT-PCR and RT-PCR. We further confirmed the binding of ERα by electrophoretic mobility shift assay (EMSA), chromatin immunoprecipitation (ChIP), Re-ChIP and luciferase assays. Fluorescence-activated cell sorting analysis (FACS) was performed to elucidate the role of ERRβ in cell cycle regulation. A Kaplan-Meier Survival analysis of GEO dataset was performed to correlate the expression of ERRβ with survival in breast cancer patients. Tissue microarray (TMA) analysis showed that ERRβ is significantly down-regulated in breast carcinoma tissue samples compared to adjacent normal. ER + ve breast tumors and cell lines showed a significant expression of ERRβ compared to ER-ve tumors and cell lines. Estrogen treatment significantly induced the expression of ERRβ and it was ERα dependent. Mechanistic analyses indicate that ERα directly targets ERRβ through estrogen response element and ERRβ also mediates cell cycle regulation through p18, p21 cip and cyclin D1 in breast cancer cells. Our results also showed the up-regulation of ERRβ promoter activity in ectopically co

Ritonavir binds to and downregulates estrogen receptors: molecular mechanism of promoting early atherosclerosis.

PubMed

Xiang, Jin; Wang, Ying; Su, Ke; Liu, Min; Hu, Peng-Chao; Ma, Tian; Li, Jia-Xi; Wei, Lei; Zheng, Zhongliang; Yang, Fang

2014-10-01

Estrogenic actions are closely related to cardiovascular disease. Ritonavir (RTV), a human immunodeficiency virus (HIV) protease inhibitor, induces atherosclerosis in an estrogen-related manner. However, how RTV induce pathological phenotypes through estrogen pathway remains unclear. In this study, we found that RTV increases thickness of coronary artery walls of Sprague Dawley rats and plasma free fatty acids (FFA) levels. In addition, RTV could induce foam cell formation, downregulate both estrogen receptor α (ERα) and ERβ expression, upregulate G protein-coupled estrogen receptor (GPER) expression, and all of them could be partially blocked by 17β-estradiol (E2), suggesting RTV acts as an antagonist for E2. Computational modeling shows a similar interaction with ERα between RTV and 2-aryl indoles, which are highly subtype-selective ligands for ERα. We also found that RTV directly bound to ERα and selectively inhibited the nuclear localization of ERα, and residue Leu536 in the hydrophobic core of ligand binding domain (LBD) was essential for the interaction with RTV. In addition, RTV did not change the secondary structure of ERα-LBD like E2, which explained how ERα lost the capacity of nuclear translocation under the treatment of RTV. All of the evidences suggest that ritonavir acts as an antagonist for 17β-estradiol in regulating α subtype estrogen receptor function and early events of atherosclerosis. Copyright © 2014 Elsevier Inc. All rights reserved.

Progesterone receptor modulates estrogen receptor-α action in breast cancer

PubMed Central

Mohammed, Hisham; Russell, I. Alasdair; Stark, Rory; Rueda, Oscar M.; Hickey, Theresa E.; Tarulli, Gerard A.; Serandour, Aurelien A. A.; Birrell, Stephen N.; Bruna, Alejandra; Saadi, Amel; Menon, Suraj; Hadfield, James; Pugh, Michelle; Raj, Ganesh V.; Brown, Gordon D.; D’Santos, Clive; Robinson, Jessica L. L.; Silva, Grace; Launchbury, Rosalind; Perou, Charles M.; Stingl, John; Caldas, Carlos; Tilley, Wayne D.; Carroll, Jason S.

2015-01-01

Summary Progesterone receptor (PR) expression is employed as a biomarker of estrogen receptor-α (ERα) function and breast cancer prognosis. We now show that PR is not merely an ERα-induced gene target, but is also an ERα-associated protein that modulates its behaviour. In the presence of agonist ligands, PR associates with ERα to direct ERα chromatin binding events within breast cancer cells, resulting in a unique gene expression programme that is associated with good clinical outcome. Progesterone inhibited estrogen-mediated growth of ERα+ cell line xenografts and primary ERα+ breast tumour explants and had increased anti-proliferative effects when coupled with an ERα antagonist. Copy number loss of PgR is a common feature in ERα+ breast cancers, explaining lower PR levels in a subset of cases. Our findings indicate that PR functions as a molecular rheostat to control ERα chromatin binding and transcriptional activity, which has important implications for prognosis and therapeutic interventions. PMID:26153859

Estrogen receptor mRNA in mineralized tissues of rainbow trout: calcium mobilization by estrogen.

PubMed

Armour, K J; Lehane, D B; Pakdel, F; Valotaire, Y; Graham, R; Russell, R G; Henderson, I W

1997-07-07

RT-PCR was undertaken on total RNA extracts from bone and scales of the rainbow trout, Oncorhynchus mykiss. The rainbow trout estrogen receptor (ER)-specific primers used amplified a single product of expected size from each tissue which, using Southern blotting, strongly hybridized with a 32P-labelled rtER probe under stringent conditions. These data provide the first in vivo evidence of ER mRNA in bone and scale tissues of rainbow trout and suggest that the effects of estrogen observed in this study (increased bone mineral and decreased scale mineral contents, respectively) may be mediated directly through ER.

Activation of G protein-coupled receptor 30 by thiodiphenol promotes proliferation of estrogen receptor α-positive breast cancer cells.

PubMed

Lei, Bingli; Peng, Wei; Xu, Gang; Wu, Minghong; Wen, Yu; Xu, Jie; Yu, Zhiqiang; Wang, Yipei

2017-02-01

Many studies have been shown that environmental estrogen bisphenol A (BPA) can activate nuclear receptor (estrogen receptor alpha, ERα) or membrane receptor (G-protein-coupled receptor, GPR30) in breast cancer cells and exerts genomic or nongenomic actions inducing cell proliferation. 4,4'-thiodiphenol (TDP) as one of BPA derivatives exhibits more potent estrogenic activity than BPA does. However, comparatively little is known about the ways in which TDP interferes with these signaling pathways and produces cell biological changes. This study evaluated the effect of TDP on cell viability, reactive oxygen species (ROS) formation, and intercellular calcium (Ca 2+ ) fluctuation in MCF-7 breast cancer cells. The underlying molecular mechanism of cell proliferation induced by TDP was analyzed by examining the activation of ERα and GPR30-mediated phosphatidylinotidol 3-kinase/protein kinase B (PI3K/AKT) and extracellular-signa1regulated kinase (ERK1/2) signaling pathways. The results showed that exposure to 0.1-10 μM TDP for 24, 48, and 72 h significantly increased viability of MCF-7 cells. At the same concentration range, TDP exposure for 3 and 24 h markedly elevated ROS production and intracellular Ca 2+ levels. In addition, 0.01-1 μM TDP significantly increased the expression of ERα, GPR30, p-AKT and p-ERK1/2 protein. Specific protein inhibitors blocked phosphorylation of ERK1/2 and AKT and decreased TDP-induced cell proliferation. These findings show that TDP activated the GPR30-PI3K/AKT and ERK1/2 pathways, and the resulting interaction with ERα stimulated MCF-7 cell proliferation. Our results indicate a novel mechanism through which TDP may exert relevant estrogenic action in ERα positive cancer cells. Copyright © 2016 Elsevier Ltd. All rights reserved.

miRNA as a New Regulatory Mechanism of Estrogen Vascular Action.

PubMed

Pérez-Cremades, Daniel; Mompeón, Ana; Vidal-Gómez, Xavier; Hermenegildo, Carlos; Novella, Susana

2018-02-06

The beneficial effects of estrogen on the cardiovascular system have been reported extensively. In fact, the incidence of cardiovascular diseases in women is lower than in age-matched men during their fertile stage of life, a benefit that disappears after menopause. These sex-related differences point to sexual hormones, mainly estrogen, as possible cardiovascular protective factors. The regulation of vascular function by estrogen is mainly related to the maintenance of normal endothelial function and is mediated by both direct and indirect gene transcription through the activity of specific estrogen receptors. Some of these mechanisms are known, but many remain to be elucidated. In recent years, microRNAs have been established as non-coding RNAs that regulate the expression of a high percentage of protein-coding genes in mammals and are related to the correct function of human physiology. Moreover, within the cardiovascular system, miRNAs have been related to physiological and pathological conditions. In this review, we address what is known about the role of estrogen-regulated miRNAs and their emerging involvement in vascular biology.

The ginsenoside PPD exerts anti-endometriosis effects by suppressing estrogen receptor-mediated inhibition of endometrial stromal cell autophagy and NK cell cytotoxicity.

PubMed

Zhang, Bing; Zhou, Wen-Jie; Gu, Chun-Jie; Wu, Ke; Yang, Hui-Li; Mei, Jie; Yu, Jia-Jun; Hou, Xiao-Fan; Sun, Jian-Song; Xu, Feng-Yuan; Li, Da-Jin; Jin, Li-Ping; Li, Ming-Qing

2018-05-14

Endometriosis (EMS) is an estrogen-dependent gynecological disease with a low autophagy level of ectopic endometrial stromal cells (eESCs). Impaired NK cell cytotoxic activity is involved in the clearance obstruction of the ectopic endometrial tissue in the abdominopelvic cavity. Protopanaxadiol (PPD) and protopanaxatriol (PPT) are two metabolites of ginsenosides, which have profound biological functions, such as anti-cancer activities. However, the role and mechanism of ginsenosides and metabolites in endometriosis are completely unknown. Here, we found that the compounds PPD, PPT, ginsenoside-Rg3 (G-Rg3), ginsenoside-Rh2 (G-Rh2), and esculentoside A (EsA) led to significant decreases in the viability of eESCs, particularly PPD (IC50 = 30.64 µM). In vitro and in vivo experiments showed that PPD promoted the expression of progesterone receptor (PR) and downregulated the expression of estrogen receptor α (ERα) in eESCs. Treatment with PPD obviously induced the autophagy of eESCs and reversed the inhibitory effect of estrogen on eESC autophagy. In addition, eESCs pretreated with PPD enhanced the cytotoxic activity of NK cells in response to eESCs. PPD decreased the numbers and suppressed the growth of ectopic lesions in a mouse EMS model. These results suggest that PPD plays a role in anti-EMS activation, possibly by restricting estrogen-mediated autophagy regulation and enhancing the cytotoxicity of NK cells. This result provides a scientific basis for potential therapeutic strategies to treat EMS by PPD or further structural modification.

Estrogen Receptors Modulation of Anxiety-Like Behavior.

PubMed

Borrow, A P; Handa, R J

2017-01-01

Estrogens exert profound effects on the expression of anxiety in humans and rodents; however, the directionality of these effects varies considerably within both clinical and preclinical literature. It is believed that discrepancies regarding the nature of estrogens' effects on anxiety are attributable to the differential effects of specific estrogen receptor (ER) subtypes. In this chapter we will discuss the relative impact on anxiety and anxiety-like behavior of each of the three main ERs: ERα, which has a generally anxiogenic effect, ERβ, which has a generally anxiolytic effect, and the G-protein-coupled ER known as GPR30, which has been found to both increase and decrease anxiety-like behavior. In addition, we will describe the known mechanisms by which these receptor subtypes exert their influence on emotional responses, focusing on the hypothalamic-pituitary-adrenal axis and the oxytocinergic and serotonergic systems. The impact of estrogens on the expression of anxiety is likely the result of their combined effects on all of these neurobiological systems. © 2017 Elsevier Inc. All rights reserved.

Estrogens Induce Rapid Cytoskeleton Re-Organization in Human Dermal Fibroblasts via the Non-Classical Receptor GPR30

PubMed Central

Carnesecchi, Julie; Malbouyres, Marilyne; de Mets, Richard; Balland, Martial; Beauchef, Gallic; Vié, Katell; Chamot, Christophe; Lionnet, Claire; Ruggiero, Florence; Vanacker, Jean-Marc

2015-01-01

The post-menopausal decrease in estrogen circulating levels results in rapid skin deterioration pointing out to a protective effect exerted by these hormones. The identity of the skin cell type responding to estrogens is unclear as are the cellular and molecular processes they elicit. Here, we reported that lack of estrogens induces rapid re-organization of the human dermal fibroblast cytoskeleton resulting in striking cell shape change. This morphological change was accompanied by a spatial re-organization of focal adhesion and a substantial reduction of their number as evidenced by vinculin and actin co-staining. Cell morphology and cytoskeleton organization was fully restored upon 17β-estradiol (E2) addition. Treatment with specific ER antagonists and cycloheximide respectively showed that the E2 acts independently of the classical Estrogen Receptors and that cell shape change is mediated by non-genomic mechanisms. E2 treatment resulted in a rapid and transient activation of ERK1/2 but not Src or PI3K. We show that human fibroblasts express the non-classical E2 receptor GPR30 and that its agonist G-1 phenocopies the effect of E2. Inhibiting GPR30 through treatment with the G-15 antagonist or specific shRNA impaired E2 effects. Altogether, our data reveal a novel mechanism by which estrogens act on skin fibroblast by regulating cell shape through the non-classical G protein-coupled receptor GPR30 and ERK1/2 activation. PMID:25781607

Estrogens induce rapid cytoskeleton re-organization in human dermal fibroblasts via the non-classical receptor GPR30.

PubMed

Carnesecchi, Julie; Malbouyres, Marilyne; de Mets, Richard; Balland, Martial; Beauchef, Gallic; Vié, Katell; Chamot, Christophe; Lionnet, Claire; Ruggiero, Florence; Vanacker, Jean-Marc

2015-01-01

The post-menopausal decrease in estrogen circulating levels results in rapid skin deterioration pointing out to a protective effect exerted by these hormones. The identity of the skin cell type responding to estrogens is unclear as are the cellular and molecular processes they elicit. Here, we reported that lack of estrogens induces rapid re-organization of the human dermal fibroblast cytoskeleton resulting in striking cell shape change. This morphological change was accompanied by a spatial re-organization of focal adhesion and a substantial reduction of their number as evidenced by vinculin and actin co-staining. Cell morphology and cytoskeleton organization was fully restored upon 17β-estradiol (E2) addition. Treatment with specific ER antagonists and cycloheximide respectively showed that the E2 acts independently of the classical Estrogen Receptors and that cell shape change is mediated by non-genomic mechanisms. E2 treatment resulted in a rapid and transient activation of ERK1/2 but not Src or PI3K. We show that human fibroblasts express the non-classical E2 receptor GPR30 and that its agonist G-1 phenocopies the effect of E2. Inhibiting GPR30 through treatment with the G-15 antagonist or specific shRNA impaired E2 effects. Altogether, our data reveal a novel mechanism by which estrogens act on skin fibroblast by regulating cell shape through the non-classical G protein-coupled receptor GPR30 and ERK1/2 activation.

Identifying a Mechanism for Crosstalk Between the Estrogen and Glucocorticoid Receptors | Center for Cancer Research

Cancer.gov

Estrogen has long been known to play important roles in the development and progression of breast cancer. Its receptor (ER), a member of the steroid receptor family, binds to estrogen response elements (EREs) in DNA and regulates gene transcription. More recently, another steroid receptor family member, the glucocorticoid receptor (GR), has been implicated in breast cancer progression, and ER/GR status is an important predictor of breast cancer outcome.

Mechanisms of estradiol-induced insulin secretion by the G protein-coupled estrogen receptor GPR30/GPER in pancreatic beta-cells.

PubMed

Sharma, Geetanjali; Prossnitz, Eric R

2011-08-01

Sexual dimorphism and supplementation studies suggest an important role for estrogens in the amelioration of glucose intolerance and diabetes. Because little is known regarding the signaling mechanisms involved in estradiol-mediated insulin secretion, we investigated the role of the G protein-coupled receptor 30, now designated G protein-coupled estrogen receptor (GPER), in activating signal transduction cascades in β-cells, leading to secretion of insulin. GPER function in estradiol-induced signaling in the pancreatic β-cell line MIN6 was assessed using small interfering RNA and GPER-selective ligands (G-1 and G15) and in islets isolated from wild-type and GPER knockout mice. GPER is expressed in MIN6 cells, where estradiol and the GPER-selective agonist G-1 mediate calcium mobilization and activation of ERK and phosphatidylinositol 3-kinase. Both estradiol and G-1 induced insulin secretion under low- and high-glucose conditions, which was inhibited by pretreatment with GPER antagonist G15 as well as depletion of GPER by small interfering RNA. Insulin secretion in response to estradiol and G-1 was dependent on epidermal growth factor receptor and ERK activation and further modulated by phosphatidylinositol 3-kinase activity. In islets isolated from wild-type mice, the GPER antagonist G15 inhibited insulin secretion induced by estradiol and G-1, both of which failed to induce insulin secretion in islets obtained from GPER knockout mice. Our results indicate that GPER activation of the epidermal growth factor receptor and ERK in response to estradiol treatment plays a critical role in the secretion of insulin from β-cells. The results of this study suggest that the activation of downstream signaling pathways by the GPER-selective ligand G-1 could represent a novel therapeutic strategy in the treatment of diabetes.

Mechanisms of Estradiol-Induced Insulin Secretion by the G Protein-Coupled Estrogen Receptor GPR30/GPER in Pancreatic β-Cells

PubMed Central

Sharma, Geetanjali

2011-01-01

Sexual dimorphism and supplementation studies suggest an important role for estrogens in the amelioration of glucose intolerance and diabetes. Because little is known regarding the signaling mechanisms involved in estradiol-mediated insulin secretion, we investigated the role of the G protein-coupled receptor 30, now designated G protein-coupled estrogen receptor (GPER), in activating signal transduction cascades in β-cells, leading to secretion of insulin. GPER function in estradiol-induced signaling in the pancreatic β-cell line MIN6 was assessed using small interfering RNA and GPER-selective ligands (G-1 and G15) and in islets isolated from wild-type and GPER knockout mice. GPER is expressed in MIN6 cells, where estradiol and the GPER-selective agonist G-1 mediate calcium mobilization and activation of ERK and phosphatidylinositol 3-kinase. Both estradiol and G-1 induced insulin secretion under low- and high-glucose conditions, which was inhibited by pretreatment with GPER antagonist G15 as well as depletion of GPER by small interfering RNA. Insulin secretion in response to estradiol and G-1 was dependent on epidermal growth factor receptor and ERK activation and further modulated by phosphatidylinositol 3-kinase activity. In islets isolated from wild-type mice, the GPER antagonist G15 inhibited insulin secretion induced by estradiol and G-1, both of which failed to induce insulin secretion in islets obtained from GPER knockout mice. Our results indicate that GPER activation of the epidermal growth factor receptor and ERK in response to estradiol treatment plays a critical role in the secretion of insulin from β-cells. The results of this study suggest that the activation of downstream signaling pathways by the GPER-selective ligand G-1 could represent a novel therapeutic strategy in the treatment of diabetes. PMID:21673097

Estrogen receptors and ischemic neuroprotection: who, what, where, and when?

PubMed

Schreihofer, Derek A; Ma, Yulin

2013-06-13

Estrogens, particularly 17β-estradiol (E2), are powerful neuroprotective agents in animal models of cerebral ischemia. Loss of endogenous E2 in women at menopause or after surgical oopherectomy leads to an increase risk of stroke, neurodegenerative disease, and cognitive decline. However, several clinical trials found detrimental effects of E2 therapy after menopause, including increased stroke risk and dementia. Recent animal and human studies now support the "critical period" hypothesis for E2 neuroprotection whereby E2 therapy must begin soon after the loss of endogenous E2 production to have a beneficial effect. Although a wide array of mechanisms has been proposed for estradiol (E2)-dependent neuroprotection in cerebral ischemia and neurodegenerative disease, most of these mechanisms involve interactions of E2 with one of its cognate receptors, estrogen receptor alpha (ERα), estrogen receptor beta (ERβ), or the G protein-coupled estrogen receptor (GPER). However, these receptors are not uniformly distributed throughout the brain, across different cell types, and within cellular compartments. Such differences likely play a role in the ability of E2 and ER selective ligands to protect the brain from ischemia. This review examines the changes in ER expression and location that may underlie the loss of E2 neuroprotection seen with aging and long-term estrogen deprivation (LTED). Recent results suggest that the loss of ERα that accompanies aging and LTED plays an important role in the loss of E2-dependent neuroprotection. This article is part of a Special Issue entitled Hormone Therapy. Copyright © 2013 Elsevier B.V. All rights reserved.

Estrogen receptor status of breast cancer in Ontario

PubMed Central

McKeown-Eyssen, Gail E.; Rogers-Melamed, Iris; Clarke, E. Aileen

1985-01-01

Data from a number of studies of breast cancer have suggested that after the ages associated with the menopause the rates of estrogen-receptor-positive tumours increase with age, whereas the rates of estrogen-receptor-negative tumours do not. Previous investigators studied cases in specific treatment centres, so there was a possibility that the findings were influenced by differences in patterns of case referral by age. A review of all the cases of breast cancer diagnosed in Ontario women in 1981 and assayed for estrogen receptors, however, confirmed the earlier findings. The results showed that the incidence of estrogen-receptor-positive and estrogen-receptor-negative tumours increased at about the same rate before age 45, but thereafter an increase in incidence was seen only for estrogen-receptor-positive tumours. These differences in patterns of incidence suggest the possibility that the two types of tumour may have different etiologic factors. PMID:4063915

Mechanism of estrogen activation of c-myc oncogene expression.

PubMed

Dubik, D; Shiu, R P

1992-08-01

The estrogen receptor complex is a known trans-acting factor that regulates transcription of specific genes through an interaction with a specific estrogen-responsive cis-acting element (ERE). In previous studies we have shown that in estrogen-responsive human breast cancer cells estrogen rapidly activates c-myc expression. This activated expression occurs through enhanced transcription and does not require the synthesis of new protein intermediates; therefore, an ERE is present in the human c-myc gene regulatory region. To localize the ERE, constructs containing varying lengths of the c-myc 5'-flanking region ranging from -2327 to +25 (relative to the P1 promoter) placed adjacent to the chloramphenicol acetyl transferase reporter gene (CAT) were prepared. They were used in transient transfection studies in MCF-7 and HeLa cells co-transfected with an estrogen receptor expression vector. These studies reveal that all constructs containing the P2 promoter region exhibited estrogen-regulated CAT expression and that a 116-bp region upstream and encompassing the P2 TATA box is necessary for this activity. Analysis of this 116-bp region failed to identify a cis-acting element with sequences resembling the consensus ERE; however, co-transfection studies with mutant estrogen receptor expression vectors showed that the DNA-binding domain of the receptor is essential for estrogen-regulated CAT gene expression. We have also observed that anti-estrogen receptor complexes can weakly trans-activate from this 116-bp region but fail to do so from the ERE-containing ApoVLDLII-CAT construct. To explain these results we propose a new mechanism of estrogen trans-activation in the c-myc gene promoter.

Pharmacology of conjugated equine estrogens: efficacy, safety and mechanism of action.

PubMed

Bhavnani, Bhagu R; Stanczyk, Frank Z

2014-07-01

Oral conjugated equine estrogens (CEE) are the most used estrogen formulation for postmenopausal hormone therapy either alone or in combination with a progestin. CEE is most commonly used for the management of early menopausal symptoms such as hot flashes, vaginitis, insomnia, and mood disturbances. Additionally, if used at the start of the menopausal phase (age 50-59 years), CEE prevents osteoporosis and may in some women reduce the risk of cardiovascular disease (CVD) and Alzheimer's disease (AD). There appears to be a common mechanism through which estrogens can protect against CVD and AD. CEE is a natural formulation of an extract prepared from pregnant mares' urine. The product monogram lists the presence of only 10 estrogens consisting of the classical estrogens, estrone and 17β-estradiol, and a group of unique ring B unsaturated estrogens such as equilin and equilenin. The ring B unsaturated estrogens are formed by an alternate steroidogenic pathway in which cholesterol is not an obligatory intermediate. Both the route of administration and structure of these estrogens play a role in the overall pharmacology of CEE. In contrast to 17β-estradiol, ring B unsaturated estrogens express their biological effects mainly mediated by the estrogen receptor β and not the estrogen receptor α. All estrogen components of CEE are antioxidants, and some ring B unsaturated estrogens have several fold greater antioxidant activity than estrone and 17β-estradiol. The cardioprotective and neuroprotective effects of CEE appear to be, to some extent, due to its ability to prevent the formation of oxidized LDL and HDL, and by inhibiting or modulating some of the key proteases involved in programmed cell death (apoptosis) induced by the excess neurotransmitter glutamate and other neurotoxins. Selective combinations of ring B unsaturated estrogens have the potential of being developed as novel therapeutic agents for the prevention of cardiovascular disease and Alzheimer

Evaluation of estrogen receptor alpha activation by glyphosate-based herbicide constituents.

PubMed

Mesnage, Robin; Phedonos, Alexia; Biserni, Martina; Arno, Matthew; Balu, Sucharitha; Corton, J Christopher; Ugarte, Ricardo; Antoniou, Michael N

2017-10-01

The safety, including the endocrine disruptive capability, of glyphosate-based herbicides (GBHs) is a matter of intense debate. We evaluated the estrogenic potential of glyphosate, commercial GBHs and polyethoxylated tallowamine adjuvants present as co-formulants in GBHs. Glyphosate (≥10,000 μg/L or 59 μM) promoted proliferation of estrogen-dependent MCF-7 human breast cancer cells. Glyphosate also increased the expression of an estrogen response element-luciferase reporter gene (ERE-luc) in T47D-KBluc cells, which was blocked by the estrogen antagonist ICI 182,780. Commercial GBH formulations or their adjuvants alone did not exhibit estrogenic effects in either assay. Transcriptomics analysis of MCF-7 cells treated with glyphosate revealed changes in gene expression reflective of hormone-induced cell proliferation but did not overlap with an ERα gene expression biomarker. Calculation of glyphosate binding energy to ERα predicts a weak and unstable interaction (-4.10 kcal mol -1 ) compared to estradiol (-25.79 kcal mol -1 ), which suggests that activation of this receptor by glyphosate is via a ligand-independent mechanism. Induction of ERE-luc expression by the PKA signalling activator IBMX shows that ERE-luc is responsive to ligand-independent activation, suggesting a possible mechanism of glyphosate-mediated activation. Our study reveals that glyphosate, but not other components present in GBHs, can activate ERα in vitro, albeit at relatively high concentrations. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

Aromatase and estrogen receptors in male reproduction.

PubMed

Carreau, Serge; Delalande, Christelle; Silandre, Dorothée; Bourguiba, Sonia; Lambard, Sophie

2006-02-26

Aromatase is a terminal enzyme which transforms irreversibly androgens into estrogens and it is present in the endoplasmic reticulum of numerous tissues. We have demonstrated that mature rat germ cells express a functional aromatase with a production of estrogens equivalent to that of Leydig cells. In humans in addition to Leydig cells, we have shown the presence of aromatase in ejaculated spermatozoa and in immature germ cells. In most tissues, high affinity estrogen receptors, ERalpha and/or ERbeta, mediate the role of estrogens. Indeed, in human spermatozoa, we have successfully amplified ERbeta mRNA but the protein was not detectable. Using ERalpha antibody we have detected two proteins in human immature germ cells: one at the expected size 66 kDa and another at 46 kDa likely corresponding to the ERalpha isoform lacking exon 1. In spermatozoa only the 46 kDa isoform was present, and we suggest that it may be located on the membrane. In addition, in men genetically deficient in aromatase, it is reported that alterations of spermatogenesis occur both in terms of the number and motility of spermatozoa. All together, these observations suggest that endogenous estrogens are important in male reproduction.

Impact of Estrogens and Estrogen Receptor Alpha (ESR1) in Brain Lipid Metabolism.

PubMed

Morselli, Eugenia; de Souza Santos, Roberta; Gao, Su; Ávalos, Yenniffer; Criollo, Alfredo; Palmer, Biff F; Clegg, Deborah J

2018-03-06

Estrogens and their receptors play key roles in regulating body weight, energy expenditure, and metabolic homeostasis. It is known that lack of estrogens promotes increased food intake and induces the expansion of adipose tissues, for which much is known. An area of estrogenic research that has received less attention is the role of estrogens and their receptors in influencing intermediary lipid metabolism in organs such as the brain. In this review, we highlight the actions of estrogens and their receptors in regulating their impact on modulating fatty acid content, utilization, and oxidation through their direct impact on intracellular signaling cascades within the central nervous system.

The unliganded long isoform of estrogen receptor beta stimulates brain ryanodine receptor single channel activity alongside with cytosolic Ca2+

PubMed Central

Rybalchenko, Volodymyr; Grillo, Michael A.; Gastinger, Matthew J.; Rybalchenko, Nataliya; Payne, Andrew J.; Koulen, Peter

2010-01-01

Ca2+ release from intracellular stores mediated by endoplasmic reticulum membrane ryanodine receptors (RyR) plays a key role in activating and synchronizing downstream Ca2+-dependent mechanisms, in different cells varying from apoptosis to nuclear transcription and development of defensive responses. Recently discovered, atypical “non-genomic” effects mediated by estrogen receptors (ER) include rapid Ca2+ release upon estrogen exposure in conditions implicitly suggesting involvement of RyRs. In the present study, we report various levels of co-localization between RyR type 2 (RyR2) and ER type β (ERβ) in the neuronal cell line HT-22, indicating a possible functional interaction. Electrophysiological analyses revealed a significant increase in single channel ionic currents generated by mouse brain RyRs after application of the soluble monomer of the long form ERβ (ERβ1). The effect was due to a strong increase in open probability of RyR higher open channel sublevels at cytosolic [Ca2+] concentrations of 100 nM, suggesting a synergistic action of ERβ1 and Ca2+ in RyR activation, and a potential contribution to Ca2+-induced Ca2+ release rather than to basal intracellular Ca2+ concentration level at rest. This RyR/ERβ interaction has potential effects on cellular physiology, including roles of shorter ERβ isoforms and modulation of the RyR/ERβ complexes by exogenous estrogens. PMID:19899956

Effects of estrogen receptor modulators on cytoskeletal proteins in the central nervous system.

PubMed

Segura-Uribe, Julia J; Pinto-Almazán, Rodolfo; Coyoy-Salgado, Angélica; Fuentes-Venado, Claudia E; Guerra-Araiza, Christian

2017-08-01

Estrogen receptor modulators are compounds of interest because of their estrogenic agonistic/antagonistic effects and tissue specificity. These compounds have many clinical applications, particularly for breast cancer treatment and osteoporosis in postmenopausal women, as well as for the treatment of climacteric symptoms. Similar to estrogens, neuroprotective effects of estrogen receptor modulators have been described in different models. However, the mechanisms of action of these compounds in the central nervous system have not been fully described. We conducted a systematic search to investigate the effects of estrogen receptor modulators in the central nervous system, focusing on the modulation of cytoskeletal proteins. We found that raloxifene, tamoxifen, and tibolone modulate some cytoskeletal proteins such as tau, microtuble-associated protein 1 (MAP1), MAP2, neurofilament 38 (NF38) by different mechanisms of action and at different levels: neuronal microfilaments, intermediate filaments, and microtubule-associated proteins. Finally, we emphasize the importance of the study of these compounds in the treatment of neurodegenerative diseases since they present the benefits of estrogens without their side effects.

Effects of estrogen receptor modulators on cytoskeletal proteins in the central nervous system

PubMed Central

Segura-Uribe, Julia J.; Pinto-Almazán, Rodolfo; Coyoy-Salgado, Angélica; Fuentes-Venado, Claudia E.; Guerra-Araiza, Christian

2017-01-01

Estrogen receptor modulators are compounds of interest because of their estrogenic agonistic/antagonistic effects and tissue specificity. These compounds have many clinical applications, particularly for breast cancer treatment and osteoporosis in postmenopausal women, as well as for the treatment of climacteric symptoms. Similar to estrogens, neuroprotective effects of estrogen receptor modulators have been described in different models. However, the mechanisms of action of these compounds in the central nervous system have not been fully described. We conducted a systematic search to investigate the effects of estrogen receptor modulators in the central nervous system, focusing on the modulation of cytoskeletal proteins. We found that raloxifene, tamoxifen, and tibolone modulate some cytoskeletal proteins such as tau, microtuble-associated protein 1 (MAP1), MAP2, neurofilament 38 (NF38) by different mechanisms of action and at different levels: neuronal microfilaments, intermediate filaments, and microtubule-associated proteins. Finally, we emphasize the importance of the study of these compounds in the treatment of neurodegenerative diseases since they present the benefits of estrogens without their side effects. PMID:28966632

Estrogen Receptors Modulation of Anxiety-Like Behavior

PubMed Central

Borrow, A.P.; Handa, R.J.

2018-01-01

Estrogens exert profound effects on the expression of anxiety in humans and rodents; however, the directionality of these effects varies considerably within both clinical and preclinical literature. It is believed that discrepancies regarding the nature of estrogens’ effects on anxiety are attributable to the differential effects of specific estrogen receptor (ER) subtypes. In this chapter we will discuss the relative impact on anxiety and anxiety-like behavior of each of the three main ERs: ERα, which has a generally anxiogenic effect, ERβ, which has a generally anxiolytic effect, and the G-protein-coupled ER known as GPR30, which has been found to both increase and decrease anxiety-like behavior. In addition, we will describe the known mechanisms by which these receptor subtypes exert their influence on emotional responses, focusing on the hypothalamic–pituitary–adrenal axis and the oxytocinergic and serotonergic systems. The impact of estrogens on the expression of anxiety is likely the result of their combined effects on all of these neurobiological systems. PMID:28061972

Glyphosate induces human breast cancer cells growth via estrogen receptors.

PubMed

Thongprakaisang, Siriporn; Thiantanawat, Apinya; Rangkadilok, Nuchanart; Suriyo, Tawit; Satayavivad, Jutamaad

2013-09-01

Glyphosate is an active ingredient of the most widely used herbicide and it is believed to be less toxic than other pesticides. However, several recent studies showed its potential adverse health effects to humans as it may be an endocrine disruptor. This study focuses on the effects of pure glyphosate on estrogen receptors (ERs) mediated transcriptional activity and their expressions. Glyphosate exerted proliferative effects only in human hormone-dependent breast cancer, T47D cells, but not in hormone-independent breast cancer, MDA-MB231 cells, at 10⁻¹² to 10⁻⁶M in estrogen withdrawal condition. The proliferative concentrations of glyphosate that induced the activation of estrogen response element (ERE) transcription activity were 5-13 fold of control in T47D-KBluc cells and this activation was inhibited by an estrogen antagonist, ICI 182780, indicating that the estrogenic activity of glyphosate was mediated via ERs. Furthermore, glyphosate also altered both ERα and β expression. These results indicated that low and environmentally relevant concentrations of glyphosate possessed estrogenic activity. Glyphosate-based herbicides are widely used for soybean cultivation, and our results also found that there was an additive estrogenic effect between glyphosate and genistein, a phytoestrogen in soybeans. However, these additive effects of glyphosate contamination in soybeans need further animal study. Copyright © 2013 Elsevier Ltd. All rights reserved.

Estrogen receptor 1 modulates circadian rhythms in adult female mice.

PubMed

Blattner, Margaret S; Mahoney, Megan M

2014-06-01

Estradiol influences the level and distribution of daily activity, the duration of the free-running period, and the behavioral phase response to light pulses. However, the mechanisms by which estradiol regulates daily and circadian rhythms are not fully understood. We tested the hypothesis that estrogens modulate daily activity patterns via both classical and "non-classical" actions at the estrogen receptor subtype 1 (ESR1). We used female transgenic mice with mutations in their estrogen response pathways; ESR1 knock-out (ERKO) mice and "non-classical" estrogen receptor knock-in (NERKI) mice. NERKI mice have an ESR1 receptor with a mutation in the estrogen-response-element binding domain, allowing only actions via "non-classical" genomic and second messenger pathways. Ovariectomized female NERKI, ERKO, and wildtype (WT) mice were given a subcutaneous capsule with low- or high-dose estradiol and compared with counterparts with no hormone replacement. We measured wheel-running activity in a light:dark cycle and constant darkness, and the behavioral phase response to light pulses given at different points during the subjective day and night. Estradiol increased average daily wheel-running, consolidated activity to the dark phase, and shortened the endogenous period in WT, but not NERKI and ERKO mice. The timing of activity onset during entrainment was advanced in all estradiol-treated animals regardless of genotype suggesting an ESR1-independent mechanism. We propose that estradiol modifies period, activity level, and distribution of activity via classical actions of ESR1 whereas an ESR1 independent mechanism regulates the phase of rhythms.

Nuclear alternate estrogen receptor GPR30 mediates 17beta-estradiol-induced gene expression and migration in breast cancer-associated fibroblasts.

PubMed

Madeo, Antonio; Maggiolini, Marcello

2010-07-15

Fibroblasts are the principal cellular component of connective tissue and are associated with cancer cells at all stages of tumor progression. Structural and functional contributions of fibroblasts to the growth, survival, and invasive capacity of cancer cells are beginning to emerge. In breast carcinoma, approximately 80% of stromal fibroblasts termed cancer-associated fibroblasts (CAF) are thought to manifest an activated phenotype that promotes cancer cell proliferation tumor growth at metastatic sites similar to the primary tumor. In this report, we show that CAFs respond to physiologic concentrations of 17beta-estradiol (E2) by rapidly inducing extracellular signal-regulated kinase phosphorylation and immediate early gene expression, including c-fos and connective tissue growth factor, and cyclin D1. Notably, the E2 response is mediated by the alternate estrogen receptor GPR30, which interfaces with the epidermal growth factor receptor (EGFR) signaling pathway. In particular, E2 stimulates a physical interaction between GPR30 and phosphorylated EGFR, recruiting them to the cyclin D1 gene promoter. Nuclear localization induced by E2 was confirmed by cellular immunofluorescence methods. GPR30 was required for CAF proliferation and migration induced by E2. Our results provide important new mechanistic insights into how CAFs are stimulated by estrogen through a GPR30-mediated nuclear signaling pathway. More generally, they define estrogenic GPR30 signaling as a functionally important component of the tumor microenvironment. (c)2010 AACR.

Estrogens and their receptors in the medial amygdala rapidly facilitate social recognition in female mice.

PubMed

Lymer, Jennifer M; Sheppard, Paul A S; Kuun, Talya; Blackman, Andrea; Jani, Nilay; Mahbub, Sahnon; Choleris, Elena

2018-03-01

Estrogens have been shown to rapidly (within 1 h) affect learning and memory processes, including social recognition. Both systemic and hippocampal administration of 17β-estradiol facilitate social recognition in female mice within 40 min of administration. These effects were likely mediated by estrogen receptor (ER) α and the G-protein coupled estrogen receptor (GPER), as administration of the respective receptor agonists (PPT and G-1) also facilitated social recognition on a rapid time scale. The medial amygdala has been shown to be necessary for social recognition and long-term manipulations in rats have implicated medial amygdalar ERα. As such, our objective was to investigate whether estrogens and different ERs within the medial amygdala play a role in the rapid facilitation of social recognition in female mice. 17β-estradiol, G-1, PPT, or ERβ agonist DPN was infused directly into the medial amygdala of ovariectomized female mice. Mice were then tested in a social recognition paradigm, which was completed within 40 min, thus allowing the assessment of rapid effects of treatments. 17β-estradiol (10, 25, 50, 100 nM), PPT (300 nM), DPN (150 nM), and G-1 (50 nM) each rapidly facilitated social recognition. Therefore, estrogens in the medial amygdala rapidly facilitate social recognition in female mice, and the three main estrogen receptors: ERα, ERβ, and the GPER all are involved in these effects. This research adds to a network of brain regions, including the medial amygdala and the dorsal hippocampus, that are involved in mediating the rapid estrogenic facilitation of social recognition in female mice. Copyright © 2017 Elsevier Ltd. All rights reserved.

Src-JNK Potentiation of Estrogen Receptor AF-1; Mechanism, and Role in Estrogen Action in Breast Cancer

DTIC Science & Technology

2002-08-01

an increase in estrogen receptor activity. A second objective is to understand the potential role of Src in estrogen induced mammary ductal development ...bPcis i on to The Ser-ilS-dependent link wt GR- t KaroBio AB, a Swedish pharmaceutical development company with CBP is in addition to the Ser-1l8...the ECL detection kit (Amersham Pharmacia Biotech ). phoresis, stained with Coomassic Blue to monitor expression, and sub- Fluorescence Microscopy

Activation of the G protein-coupled estrogen receptor, but not estrogen receptor α or β, rapidly enhances social learning.

PubMed

Ervin, Kelsy Sharice Jean; Mulvale, Erin; Gallagher, Nicola; Roussel, Véronique; Choleris, Elena

2015-08-01

Social learning is a highly adaptive process by which an animal acquires information from a conspecific. While estrogens are known to modulate learning and memory, much of this research focuses on individual learning. Estrogens have been shown to enhance social learning on a long-term time scale, likely via genomic mechanisms. Estrogens have also been shown to affect individual learning on a rapid time scale through cell-signaling cascades, rather than via genomic effects, suggesting they may also rapidly influence social learning. We therefore investigated the effects of 17β-estradiol and involvement of the estrogen receptors (ERs) using the ERα agonist propyl pyrazole triol, the ERβ agonist diarylpropionitrile, and the G protein-coupled ER 1 (GPER1) agonist G1 on the social transmission of food preferences (STFP) task, within a time scale that focused on the rapid effects of estrogens. General ER activation with 17β-estradiol resulted in a modest facilitation of social learning, with mice showing a preference up to 30min of testing. Specific activation of the GPER1 also rapidly enhanced social learning, with mice showing a socially learned preference up to 2h of testing. ERα activation instead shortened the expression of a socially learned food preference, while ERβ activation had little to no effects. Thus, rapid estrogenic modulation of social learning in the STFP may be the outcome of competing action at the three main receptors. Hence, estrogens' rapid effects on social learning likely depend on the specific ERs present in brain regions recruited during social learning. Copyright © 2015 Elsevier Ltd. All rights reserved.

Genomic variation in the MMP-1 promoter influences estrogen receptor mediated activity in a mechanically activated environment: potential implications for microgravity risk assessment

NASA Astrophysics Data System (ADS)

Thaler, John; Myers, Ken; Lu, Ting; Hart, David

Background: Mechanotransduction, the conversion of mechanical forces (tensile, compression, shear etc.) into cellular signals is a significant response mechanism in bone that contributes to the balance between formation and resorption and helps maintain bone density. In microgravity the lack of mechanical signals can lead to a loss of bone density, however the signaling pathways responsible are not well understood. For women, sex-specific hormones are also important in maintaining bone density since estrogen deficiency is a major factor in the etiology of osteoporosis in postmenopausal women. Estrogen Receptors (ERs) are present in human connective tissue cells such as osteoblasts and may play a role in mechanotransduction responses. The two ER isoforms, alpha (ER-α) and beta (ER-β) differentially regulate expression of matrixmetalloproteinases (MMPs) which degrade extracellular matrix components found in connective tissues. Mechanical stimulation is known to affect the expression of MMP-1, a collagenase involved in the bone resorption process. The MMP-1 promoter region contains a single nucleotide polymorphism of an additional guanine (G) at position -1607 bp which creates a binding site for a member of the Ets family of mammalian transcription factors. The 2G allele is known to be present in 45-70% of healthy populations and has been associated with higher MMP-1 expression. The 2G allele has been linked to higher risk of several types of cancer but a link to osteoporosis or microgravity induced bone loss has not been explored. The purpose of the present study was to conduct a case-study to determine whether small genetic variations can influence cellular and tissue responses to mechanical loading. Specifically we examined the potential of the 1G/2G -1607 MMP-1 promoter SNP to alter the interplay between mechanical shear stress and estrogen receptors in controlling MMP-1 expression. Methods: Rabbit synovial cells (HIG-82) were used as an in vitro model system to

Epidermal growth factor induces G protein-coupled receptor 30 expression in estrogen receptor-negative breast cancer cells.

PubMed

Albanito, Lidia; Sisci, Diego; Aquila, Saveria; Brunelli, Elvira; Vivacqua, Adele; Madeo, Antonio; Lappano, Rosamaria; Pandey, Deo Prakash; Picard, Didier; Mauro, Loredana; Andò, Sebastiano; Maggiolini, Marcello

2008-08-01

Different cellular receptors mediate the biological effects induced by estrogens. In addition to the classical nuclear estrogen receptors (ERs)-alpha and -beta, estrogen also signals through the seven-transmembrane G-protein-coupled receptor (GPR)-30. Using as a model system SkBr3 and BT20 breast cancer cells lacking the classical ER, the regulation of GPR30 expression by 17beta-estradiol, the selective GPR30 ligand G-1, IGF-I, and epidermal growth factor (EGF) was evaluated. Transient transfections with an expression plasmid encoding a short 5'-flanking sequence of the GPR30 gene revealed that an activator protein-1 site located within this region is required for the activating potential exhibited only by EGF. Accordingly, EGF up-regulated GPR30 protein levels, which accumulated predominantly in the intracellular compartment. The stimulatory role elicited by EGF on GPR30 expression was triggered through rapid ERK phosphorylation and c-fos induction, which was strongly recruited to the activator protein-1 site found in the short 5'-flanking sequence of the GPR30 gene. Of note, EGF activating the EGF receptor-MAPK transduction pathway stimulated a regulatory loop that subsequently engaged estrogen through GPR30 to boost the proliferation of SkBr3 and BT20 breast tumor cells. The up-regulation of GPR30 by ligand-activated EGF receptor-MAPK signaling provides new insight into the well-known estrogen and EGF cross talk, which, as largely reported, contributes to breast cancer progression. On the basis of our results, the action of EGF may include the up-regulation of GPR30 in facilitating a stimulatory role of estrogen, even in ER-negative breast tumor cells.

Estrogen Receptor α Deficiency Modulates TLR Ligand-Mediated PDC-TREM Expression in Plasmacytoid Dendritic Cells in Lupus-Prone Mice.

PubMed

Scott, Jennifer L; Cunningham, Melissa A; Naga, Osama S; Wirth, Jena R; Eudaly, Jackie G; Gilkeson, Gary S

2015-12-15

Female lupus-prone NZM2410 estrogen receptor α (ERα)-deficient mice are protected from renal disease and have prolonged survival compared with wild-type littermates; however, the mechanism of protection is unknown. Plasmacytoid dendritic cells (pDCs) and type I IFN drive lupus pathogenesis. Estrogen acting via ERα enhances both pDC development and IFN production. The objectives for this study were to determine if ERα modulates pDC function and IFN activity in predisease NZM2410 mice as a possible protective mechanism of ERα deficiency in lupus-prone mice. We measured the effect of ERα deficiency on spleen pDC frequency, number, maturation, and activation state. ERα deficiency reduced type I IFN activity and the frequency of MHC class II(+) pDCs in the spleen without altering overall pDC frequency, number, or maturation state. Additionally, ERα-deficient NZM2410 mice had a significantly decreased frequency of pDCs expressing PDC-TREM, a modulator of TLR-mediated IFN production. After in vitro TLR9 stimulation, ERα deficiency significantly reduced the expression of PDC-TREM on pDCs from both NZM2410 and C57BL/6 mice. Thus, we have identified a significant effect of ERα deficiency on pDCs in predisease NZM2410 mice, which may represent a mechanism by which ERα deficiency protects NZM2410 mice from lupuslike disease. Copyright © 2015 by The American Association of Immunologists, Inc.

Estrogen Receptors and Chronic Venous Disease.

PubMed

Serra, R; Gallelli, L; Perri, P; De Francesco, E M; Rigiracciolo, D C; Mastroroberto, P; Maggiolini, M; de Franciscis, S

2016-07-01

Chronic venous disease (CVD) is a common and relevant problem affecting Western people. The role of estrogens and their receptors in the venous wall seems to support the major prevalence of CVD in women. The effects of the estrogens are mediated by three estrogen receptors (ERs): ERα, ERβ, and G protein-coupled ER (GPER). The expression of ERs in the vessel walls of varicose veins is evaluated. In this prospective study, patients of both sexes, with CVD and varicose veins undergoing open venous surgery procedures, were enrolled in order to obtain vein samples. To obtain control samples of healthy veins, patients of both sexes without CVD undergoing coronary artery bypass grafting with autologous saphenous vein were recruited (control group). Samples were processed in order to evaluate gene expression. Forty patients with CVD (10 men [25%], 30 women [75%], mean age 54.3 years [median 52 years, range 33-74 years]) were enrolled. Five patients without CVD (three men, two women [aged 61-73 years]) were enrolled as the control group. A significant increase of tissue expression of ERα, ERβ and GPER in patients with CVD was recorded (p < .01), which was also related to the severity of venous disease. ERs seem to play a role in CVD; in this study, the expression of ERs correlated with the severity of the disease, and their expression was correlated with the clinical stage. Copyright © 2016 European Society for Vascular Surgery. Published by Elsevier Ltd. All rights reserved.

Protein Kinase Cα Modulates Estrogen-Receptor-Dependent Transcription and Proliferation in Endometrial Cancer Cells

PubMed Central

Thorne, Alicia M.; Jackson, Twila A.; Willis, Van C.; Bradford, Andrew P.

2013-01-01

Endometrial cancer is the most common invasive gynecologic malignancy in developed countries. The most prevalent endometrioid tumors are linked to excessive estrogen exposure and hyperplasia. However, molecular mechanisms and signaling pathways underlying their etiology and pathophysiology remain poorly understood. We have shown that protein kinase Cα (PKCα) is aberrantly expressed in endometrioid tumors and is an important mediator of endometrial cancer cell survival, proliferation, and invasion. In this study, we demonstrate that expression of active, myristoylated PKCα conferred ligand-independent activation of estrogen-receptor- (ER-) dependent promoters and enhanced responses to estrogen. Conversely, knockdown of PKCα reduced ER-dependent gene expression and inhibited estrogen-induced proliferation of endometrial cancer cells. The ability of PKCα to potentiate estrogen activation of ER-dependent transcription was attenuated by inhibitors of phosphoinositide 3-kinase (PI3K) and Akt. Evidence suggests that PKCα and estrogen signal transduction pathways functionally interact, to modulate ER-dependent growth and transcription. Thus, PKCα signaling, via PI3K/Akt, may be a critical element of the hyperestrogenic environment and activation of ER that is thought to underlie the development of estrogen-dependent endometrial hyperplasia and malignancy. PKCα-dependent pathways may provide much needed prognostic markers of aggressive disease and novel therapeutic targets in ER positive tumors. PMID:23843797

Ritonavir binds to and downregulates estrogen receptors: Molecular mechanism of promoting early atherosclerosis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xiang, Jin; Wang, Ying; Su, Ke

Estrogenic actions are closely related to cardiovascular disease. Ritonavir (RTV), a human immunodeficiency virus (HIV) protease inhibitor, induces atherosclerosis in an estrogen-related manner. However, how RTV induce pathological phenotypes through estrogen pathway remains unclear. In this study, we found that RTV increases thickness of coronary artery walls of Sprague Dawley rats and plasma free fatty acids (FFA) levels. In addition, RTV could induce foam cell formation, downregulate both estrogen receptor α (ERα) and ERβ expression, upregulate G protein-coupled estrogen receptor (GPER) expression, and all of them could be partially blocked by 17β-estradiol (E2), suggesting RTV acts as an antagonist formore » E2. Computational modeling shows a similar interaction with ERα between RTV and 2-aryl indoles, which are highly subtype-selective ligands for ERα. We also found that RTV directly bound to ERα and selectively inhibited the nuclear localization of ERα, and residue Leu536 in the hydrophobic core of ligand binding domain (LBD) was essential for the interaction with RTV. In addition, RTV did not change the secondary structure of ERα-LBD like E2, which explained how ERα lost the capacity of nuclear translocation under the treatment of RTV. All of the evidences suggest that ritonavir acts as an antagonist for 17β-estradiol in regulating α subtype estrogen receptor function and early events of atherosclerosis. - Graphical abstract: RTV directly binds to ERα and Leu536 in the hydrophobic core of ligand binding domain is essential for the interaction. - Highlights: • RTV increases the thickness of rat coronary artery wall and foam cell formation. • RTV downregulates the expression of ERα and ERβ. • RTV inhibits ERα promoter activity. • RTV directly binds to ERα and the key amino acid is Leu536. • RTV inhibits the nuclear translocation of ERα and GPER.« less

Expression and localization of aromatase P450AROM, estrogen receptor-α, and estrogen receptor-β in the developing fetal bovine frontal cortex.

PubMed

Peruffo, A; Giacomello, M; Montelli, S; Corain, L; Cozzi, B

2011-06-01

The enzyme aromatase (P450(AROM)) converts testosterone (T) into 17-β estradiol (E(2)) and is crucial for the control of development of the central nervous system during ontogenesis. The effects of E(2) in various brain areas are mediated by the estrogen receptor alpha (ER-α) and the estrogen receptor beta (ER-β). During fetal development, steroids are responsible for the sexual differentiation of the hypothalamus. Estrogens are also able to exert effects in other brain areas of the fetus including the frontal cortex, where they act through estrogen receptors (ERs) modulating cognitive function and affective behaviors. In this study we have determined the expression profiles of P450(AROM) and ERs in the fetal bovine frontal cortex by quantitative Real-Time PCR (qRT-PCR) throughout the prenatal development. The data show that the patterns of expression of both ERs are strongly correlated during pregnancy and increase in the last stage of gestation. On the contrary, the expression of P450(AROM) has no correlation with ERs expression and is not developmentally regulated. Moreover, we performed immunochemical studies showing that fetal neurons express P450(AROM) and the ERs. P450(AROM) is localized in the cytoplasm and only seldom present in the fine extensions of the cells; ER-α is detected predominantly in the soma whereas ER-β is only present in the nucleus of a few cells. This study provides new data on the development of the frontal cortex in a long gestation mammal with a large convoluted brain. Copyright © 2011 Elsevier Inc. All rights reserved.

Expression and functional roles of estrogen receptor GPR30 in human intervertebral disc.

PubMed

Wei, Aiqun; Shen, Bojiang; Williams, Lisa A; Bhargav, Divya; Yan, Feng; Chong, Beng H; Diwan, Ashish D

2016-04-01

Estrogen withdrawal, a characteristic of female aging, is associated with age-related intervertebral disc (IVD) degeneration. The function of estrogen is mediated by two classic nuclear receptors, estrogen receptor (ER)-α and -β, and a membrane bound G-protein-coupled receptor 30 (GPR30). To date, the expression and function of GPR30 in human spine is poorly understood. This study aimed to evaluate GPR30 expression in IVD, and its role in estrogen-related regulation of proliferation and apoptosis of disc nucleus pulposus (NP) cells. GPR30 expression was examined in 30 human adult NP and 9 fetal IVD. Results showed that GPR30 was expressed in NP cells at both mRNA and protein levels. In human fetal IVD, GPR30 protein was expressed in the NP at 12-14 weeks gestation, but was undetectable at 8-11 weeks. The effect of 17β-estradiol (E2) on GPR30-mediated proliferation and interleukin-1β (IL-1β)-induced apoptosis of NP cells was investigated. Cultured NP cells were treated with or without E2, GPR30 antagonist G36, and ER antagonist ICI 182,780. NP cell viability was tested by MTS assay. Apoptosis was determined by flow cytometry using fluorescence labeled annexin-V, TUNEL assay and immumnocytochemical staining of activated caspase-3. E2 enhanced cell proliferation and prevented IL-1β-induced cell death, but the effect was partially blocked by G36 and completely abrogated by a combination of ICI 182,780 and G36. This study demonstrates that GPR30 is expressed in human IVD to transmit signals triggering E2-induced NP cell proliferation and protecting against IL-1β-induced apoptosis. The effects of E2 on NP cells require both GPR30 and classic estrogen receptors. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

Targeting estrogen/estrogen receptor alpha enhances Bacillus Calmette-Guérin efficacy in bladder cancer

PubMed Central

Shang, Zhiqun; Li, Yanjun; Hsu, Iawen; Zhang, Minghao; Tian, Jing; Wen, Simeng; Han, Ruifa; Messing, Edward M.; Chang, Chawnshang; Niu, Yuanjie; Yeh, Shuyuan

2016-01-01

Recent studies showed the potential linkage of estrogen/estrogen receptor signaling with bladder tumorigenesis, yet detailed mechanisms remain elusive. Here we found a new potential therapy with the combination of Bacillus Calmette Guerin (BCG) and the anti-estrogen ICI 182,780 led to better suppression of bladder cancer (BCa) than BCG alone. Mechanism dissection found ICI 182,780 could promote BCG attachment/internalization to the BCa cells through increased integrin-α5β1 expression and IL-6 release, which may enhance BCG-induced suppression of BCa cell growth via recruiting more monocytes/macrophages to BCa cells and increased TNF-α release. Consistently, in vivo studies found ICI 182,780 could potentiate the anti-BCa effects of BCG in the carcinogen-induced mouse BCa models. Together, these in vitro and in vivo results suggest that combining BCG with anti-estrogen may become a new therapeutic approach with better efficacy to suppress BCa progression and recurrence. PMID:27092883

Targeting estrogen/estrogen receptor alpha enhances Bacillus Calmette-Guérin efficacy in bladder cancer.

PubMed

Shang, Zhiqun; Li, Yanjun; Hsu, Iawen; Zhang, Minghao; Tian, Jing; Wen, Simeng; Han, Ruifa; Messing, Edward M; Chang, Chawnshang; Niu, Yuanjie; Yeh, Shuyuan

2016-05-10

Recent studies showed the potential linkage of estrogen/estrogen receptor signaling with bladder tumorigenesis, yet detailed mechanisms remain elusive. Here we found a new potential therapy with the combination of Bacillus Calmette-Guerin (BCG) and the anti-estrogen ICI 182,780 led to better suppression of bladder cancer (BCa) than BCG alone. Mechanism dissection found ICI 182,780 could promote BCG attachment/internalization to the BCa cells through increased integrin-α5β1 expression and IL-6 release, which may enhance BCG-induced suppression of BCa cell growth via recruiting more monocytes/macrophages to BCa cells and increased TNF-α release. Consistently, in vivo studies found ICI 182,780 could potentiate the anti-BCa effects of BCG in the carcinogen-induced mouse BCa models. Together, these in vitro and in vivo results suggest that combining BCG with anti-estrogen may become a new therapeutic approach with better efficacy to suppress BCa progression and recurrence.

Phytoestrogens and Mycoestrogens Induce Signature Structure Dynamics Changes on Estrogen Receptor α

PubMed Central

Chen, Xueyan; Uzuner, Ugur; Li, Man; Shi, Weibing; Yuan, Joshua S.; Dai, Susie Y.

2016-01-01

Endocrine disrupters include a broad spectrum of chemicals such as industrial chemicals, natural estrogens and androgens, synthetic estrogens and androgens. Phytoestrogens are widely present in diet and food supplements; mycoestrogens are frequently found in grains. As human beings and animals are commonly exposed to phytoestrogens and mycoestrogens in diet and environment, it is important to understand the potential beneficial or hazardous effects of estrogenic compounds. Many bioassays have been established to study the binding of estrogenic compounds with estrogen receptor (ER) and provided rich data in the literature. However, limited assays can offer structure information with regard to the ligand/ER complex. Our current study surveys the global structure dynamics changes for ERα ligand binding domain (LBD) when phytoestrogens and mycoestrogens bind. The assay is based on the structure dynamics information probed by hydrogen deuterium exchange mass spectrometry and offers a unique viewpoint to elucidate the mechanism how phytoestrogens and mycoestrogens interact with estrogen receptor. The cluster analysis based on the hydrogen deuterium exchange (HDX) assay data reveals a unique pattern when phytoestrogens and mycoestrogens bind with ERα LBD compared to that of estradiol and synthetic estrogen modulators. Our study highlights that structure dynamics could play an important role in the structure function relationship when endocrine disrupters interact with estrogen receptors. PMID:27589781

The Molecular, Cellular and Clinical Consequences of Targeting the Estrogen Receptor Following Estrogen Deprivation Therapy

PubMed Central

Fan, Ping; Maximov, Philipp Y.; Curpan, Ramona F.; Abderrahman, Balkees; Jordan, V. Craig

2015-01-01

During the past twenty years our understanding of the control of breast tumor development, growth and survival has changed dramatically. The once long forgotten application of high dose synthetic estrogen therapy as the first chemical therapy to treat any cancer has been resurrected, refined and reinvented as the new biology of estrogen-induced apoptosis. High dose estrogen therapy was cast aside once tamoxifen, from its origins as a failed “morning after pill”, was reinvented as the first targeted therapy to treat any cancer. The current understanding of the mechanism of estrogen-induced apoptosis is described as a consequence of acquired resistance to long term antihormone therapy in estrogen receptor (ER) positive breast cancer. The ER signal transduction pathway remains a target for therapy in breast cancer despite “antiestrogen” resistance, but becomes a regulator of resistance. Multiple mechanisms of resistance come into play: Selective ER Modulator (SERM) stimulated growth, growth factor/ER crosstalk, estrogen-induced apoptosis and mutations of ER. But it is with the science of estrogen-induced apoptosis that the next innovation in women’s health will be developed. Recent evidence suggests that the glucocorticoid properties of medroxyprogesterone acetate blunt estrogen-induced apoptosis in estrogen deprived breast cancer cell populations. As a result breast cancer develops during long-term Hormone Replacement Therapy (HRT). A new synthetic progestin with estrogen-like properties, such as the 19 nortestosterone derivatives used in oral contraceptives, will continue to protect the uterus from unopposed estrogen stimulation but at the same time, reinforce apoptosis in vulnerable populations of nascent breast cancer cells. PMID:26052034

Human sex hormone-binding globulin binding affinities of 125 structurally diverse chemicals and comparison with their binding to androgen receptor, estrogen receptor, and α-fetoprotein.

PubMed

Hong, Huixiao; Branham, William S; Ng, Hui Wen; Moland, Carrie L; Dial, Stacey L; Fang, Hong; Perkins, Roger; Sheehan, Daniel; Tong, Weida

2015-02-01

One endocrine disruption mechanism is through binding to nuclear receptors such as the androgen receptor (AR) and estrogen receptor (ER) in target cells. The concentration of a chemical in serum is important for its entry into the target cells to bind the receptors, which is regulated by the serum proteins. Human sex hormone-binding globulin (SHBG) is the major transport protein in serum that can bind androgens and estrogens and thus change a chemical's availability to enter the target cells. Sequestration of an androgen or estrogen in the serum can alter the chemical elicited AR- and ER-mediated responses. To better understand the chemical-induced endocrine activity, we developed a competitive binding assay using human pregnancy plasma and measured the binding to the human SHBG for 125 structurally diverse chemicals, most of which were known to bind AR and ER. Eighty seven chemicals were able to bind the human SHBG in the assay, whereas 38 chemicals were nonbinders. Binding data for human SHBG are compared with that for rat α-fetoprotein, ER and AR. Knowing the binding profiles between serum and nuclear receptors will improve assessment of a chemical's potential for endocrine disruption. The SHBG binding data reported here represent the largest data set of structurally diverse chemicals tested for human SHBG binding. Utilization of the SHBG binding data with AR and ER binding data could enable better evaluation of endocrine disrupting potential of chemicals through AR- and ER-mediated responses since sequestration in serum could be considered. Published by Oxford University Press on behalf of the Society of Toxicology 2014. This work is written by US Government employees and is in the public domain in the US.

“Rapid Estrogen Signaling in the Brain: Implications for the Fine-Tuning of Neuronal Circuitry”

PubMed Central

Srivastava, Deepak P.; Waters, Elizabeth M.; Mermelstein, Paul G.; Kramár, Enikö A.; Shors, Tracey J.; Liu, Feng

2011-01-01

Rapid actions of estrogens were first described over 40 years ago. However, the importance of rapid estrogen-mediated actions in the central nervous system (CNS) has only now becoming apparent. Several lines of evidence demonstrate that rapid estrogen-mediated signaling elicits potent effects on molecular and cellular events, resulting in the fine-tuning of neuronal circuitry. At an ultrastructural level, the details of estrogen receptor localization and how these are regulated by the circulating hormone and age, are now becoming evident. Furthermore, the mechanisms that allow membrane-associated estrogen receptors to couple with intracellular signaling pathways are also now being revealed. Elucidation of complex actions of rapid estrogen-mediated signaling on synaptic proteins, connectivity and synaptic function in pyramidal neurons has demonstrated that this neurosteroid engage specific mechanisms in different areas of the brain. The regulation of synaptic properties most likely underlies the ‘fine-tuning’ of neuronal circuitry. This in turn may influence how learned behaviors are encoded by different circuitry in male and female subjects. Importantly, as estrogens have been suggested as potential treatments of a number of disorders of the CNS, advancements in our understanding of rapid estrogen signaling in the brain will serve to aid in the development of potential novel estrogen-based treatments. PMID:22072656

Estrogen-related receptor alpha is critical for the growth of estrogen receptor-negative breast cancer

PubMed Central

Stein, Rebecca A.; Chang, Ching-yi; Kazmin, Dmitri A.; Way, James; Schroeder, Thies; Wergin, Melanie; Dewhirst, Mark W.; McDonnell, Donald P.

2009-01-01

Expression of estrogen-related receptor alpha (ERRα) has recently been shown to carry negative prognostic significance in breast and ovarian cancers. The specific role of this orphan nuclear receptor in tumor growth and progression, however, is yet to be fully understood. The significant homology between estrogen receptor alpha (ERα) and ERRα initially suggested that these receptors may have similar transcriptional targets. Using the well-characterized ERα-positive MCF-7 breast cancer cell line, we sought to gain a genome-wide picture of ERα-ERRα cross-talk using an unbiased microarray approach. In addition to generating a host of novel ERRα target genes, this study yielded the surprising result that most ERRα-regulated genes are unrelated to estrogen-signaling. The relatively small number of genes regulated by both ERα and ERRα led us to expand our study to the more aggressive and less clinically treatable ERα-negative class of breast cancers. In this setting we found that ERRα expression is required for the basal level of expression of many known and novel ERRα target genes. Introduction of an siRNA directed to ERRα into the highly aggressive breast carcinoma MDA-MB-231 cell line dramatically reduced the migratory potential of these cells. Although stable knockdown of ERRα expression in MDA-MB-231 cells had no impact on in vitro cell proliferation, a significant reduction of tumor growth rate was observed when these cells were implanted as xenografts. Our results confirm a role for ERRα in breast cancer growth and highlight it as a potential therapeutic target for estrogen receptor-negative breast cancer. PMID:18974123

Estrogen Receptor-α in the Medial Amygdala Prevents Stress-Induced Elevations in Blood Pressure in Females.

PubMed

Hinton, Antentor Othrell; He, Yanlin; Xia, Yan; Xu, Pingwen; Yang, Yongjie; Saito, Kenji; Wang, Chunmei; Yan, Xiaofeng; Shu, Gang; Henderson, Alexander; Clegg, Deborah J; Khan, Sohaib A; Reynolds, Corey; Wu, Qi; Tong, Qingchun; Xu, Yong

2016-06-01

Psychological stress contributes to the development of hypertension in humans. The ovarian hormone, estrogen, has been shown to prevent stress-induced pressor responses in females by unknown mechanisms. Here, we showed that the antihypertensive effects of estrogen during stress were blunted in female mice lacking estrogen receptor-α in the brain medial amygdala. Deletion of estrogen receptor-α in medial amygdala neurons also resulted in increased excitability of these neurons, associated with elevated ionotropic glutamate receptor expression. We further demonstrated that selective activation of medial amygdala neurons mimicked effects of stress to increase blood pressure in mice. Together, our results support a model where estrogen acts on estrogen receptor-α expressed by medial amygdala neurons to prevent stress-induced activation of these neurons, and therefore prevents pressor responses to stress. © 2016 American Heart Association, Inc.

Expression of estrogen and progesterone receptors in astrocytomas: a literature review

PubMed Central

Tavares, Cléciton Braga; Gomes-Braga, Francisca das Chagas Sheyla Almeida; Costa-Silva, Danylo Rafhael; Escórcio-Dourado, Carla Solange; Borges, Umbelina Soares; Conde, Airton Mendes; da Conceição Barros-Oliveira, Maria; Sousa, Emerson Brandão; da Rocha Barros, Lorena; Martins, Luana Mota; Facina, Gil; da-Silva, Benedito Borges

2016-01-01

Gliomas are the most common type of primary central nervous system neoplasm. Astrocytomas are the most prevalent type of glioma and these tumors may be influenced by sex steroid hormones. A literature review for the presence of estrogen and progesterone receptors in astrocytomas was conducted in the PubMed database using the following MeSH terms: “estrogen receptor beta” OR “estrogen receptor alpha” OR “estrogen receptor antagonists” OR “progesterone receptors” OR “astrocytoma” OR “glioma” OR “glioblastoma”. Among the 111 articles identified, 13 studies met our inclusion criteria. The majority of reports showed the presence of estrogen and progesterone receptors in astrocytomas. Overall, higher tumor grades were associated with decreased estrogen receptor expression and increased progesterone receptor expression. PMID:27626480

Stimulating the GPR30 estrogen receptor with a novel tamoxifen analogue activates SF-1 and promotes endometrial cell proliferation.

PubMed

Lin, Benjamin C; Suzawa, Miyuki; Blind, Raymond D; Tobias, Sandra C; Bulun, Serdar E; Scanlan, Thomas S; Ingraham, Holly A

2009-07-01

Estrogens and selective estrogen receptor (ER) modulators such as tamoxifen are known to increase uterine cell proliferation. Mounting evidence suggests that estrogen signaling is mediated not only by ERalpha and ERbeta nuclear receptors, but also by GPR30 (GPER), a seven transmembrane (7TM) receptor. Here, we report that primary human endometriotic H-38 cells express high levels of GPR30 with no detectable ERalpha or ERbeta. Using a novel tamoxifen analogue, STX, which activates GPR30 but not ERs, significant stimulation of the phosphatidylinositol 3-kinase (PI3K) and mitogen-activated protein kinase (MAPK) pathways was observed in H-38 cells and in Ishikawa endometrial cancer cells expressing GPR30; a similar effect was observed in JEG3 choriocarcinoma cells. STX treatment also increased cellular pools of phosphatidylinositol (3,4,5) triphosphate, a proposed ligand for the nuclear hormone receptor SF-1 (NR5A1). Consistent with these findings, STX, tamoxifen, and the phytoestrogen genistein were able to increase SF-1 transcription, promote Ishikawa cell proliferation, and induce the SF-1 target gene aromatase in a GPR30-dependent manner. Our findings suggest a novel signaling paradigm that is initiated by estrogen activation of the 7TM receptor GPR30, with signal transduction cascades (PI3K and MAPK) converging on nuclear hormone receptors (SF-1/LRH-1) to modulate their transcriptional output. We propose that this novel GPR30/SF-1 pathway increases local concentrations of estrogen, and together with classic ER signaling, mediate the proliferative effects of synthetic estrogens such as tamoxifen, in promoting endometriosis and endometrial cancers.

Estrogen action and prostate cancer

PubMed Central

Nelles, Jason L; Hu, Wen-Yang; Prins, Gail S

2011-01-01

Early work on the hormonal basis of prostate cancer focused on the role of androgens, but more recently estrogens have been implicated as potential agents in the development and progression of prostate cancer. In this article, we review the epidemiological, laboratory and clinical evidence that estrogen may play a causative role in human prostate cancer, as well as rodent and grafted in vivo models. We then review recent literature highlighting potential mechanisms by which estrogen may contribute to prostate cancer, including estrogenic imprinting and epigenetic modifications, direct genotoxicity, hyperprolactinemia, inflammation and immunologic changes, and receptor-mediated actions. We discuss the work performed so far separating the actions of the different known estrogen receptors (ERs), ERα and ERβ, as well as G-protein-coupled receptor 30 and their specific roles in prostate disease. Finally, we predict that future work in this field will involve more investigations into epigenetic changes, experiments using new models of hormonal dysregulation in developing human prostate tissue, and continued delineation of the roles of the different ER subtypes, as well as their downstream signaling pathways that may serve as therapeutic targets. PMID:21765856

The G protein-coupled estrogen receptor GPER in health and disease

PubMed Central

Prossnitz, Eric R.; Barton, Matthias

2012-01-01

Estrogens mediate profound effects throughout the body, and regulate physiological and pathological processes in both women and men. The decreased incidence of many diseases in premenopausal women is attributed to the presence of 17β-estradiol, the predominant and most potent endogenous estrogen. In addition to endogenous estrogens, however, several manmade and plant-derived molecules also exhibit estrogenic activity. Traditionally, the actions of 17β-estradiol are ascribed to two nuclear estrogen receptors (ERs), ERα and ERβ, which function as ligand-activated transcription factors. However, 17β-estradiol also mediates rapid signaling events via pathways that involve transmembrane ERs, such as G-protein-coupled ER 1, (GPER, formerly known as GPR30). In the past 10 years, GPER has been implicated in both rapid signaling and transcriptional regulation. With the discovery of GPER-selective ligands that can selectively modulate GPER function in cell experiments and preclinical studies, and the use of GPER-knockout mice, many more potential roles for GPER are currently being elucidated. This Review highlights the physiological roles of GPER in the reproductive, nervous, endocrine, immune and cardiovascular systems, as well as its pathological roles in a diverse array of disorders including cancer. GPER is emerging as a novel therapeutic target and prognostic indicator for these diseases. PMID:21844907

The G-protein-coupled estrogen receptor GPER in health and disease.

PubMed

Prossnitz, Eric R; Barton, Matthias

2011-08-16

Estrogens mediate profound effects throughout the body and regulate physiological and pathological processes in both women and men. The low prevalence of many diseases in premenopausal women is attributed to the presence of 17β-estradiol, the predominant and most potent endogenous estrogen. In addition to endogenous estrogens, several man-made and plant-derived molecules, such as bisphenol A and genistein, also exhibit estrogenic activity. Traditionally, the actions of 17β-estradiol are ascribed to two nuclear estrogen receptors (ERs), ERα and ERβ, which function as ligand-activated transcription factors. However, 17β-estradiol also mediates rapid signaling events via pathways that involve transmembrane ERs, such as G-protein-coupled ER 1 (GPER; formerly known as GPR30). In the past 10 years, GPER has been implicated in both rapid signaling and transcriptional regulation. With the discovery of GPER-selective ligands that can selectively modulate GPER function in vitro and in preclinical studies and with the use of Gper knockout mice, many more potential roles for GPER are being elucidated. This Review highlights the physiological roles of GPER in the reproductive, nervous, endocrine, immune and cardiovascular systems, as well as its pathological roles in a diverse array of disorders including cancer, for which GPER is emerging as a novel therapeutic target and prognostic indicator.

Estrogen, vascular estrogen receptor and hormone therapy in postmenopausal vascular disease.

PubMed

Khalil, Raouf A

2013-12-15

Cardiovascular disease (CVD) is less common in premenopausal women than men of the same age or postmenopausal women, suggesting vascular benefits of estrogen. Estrogen activates estrogen receptors ERα, ERβ and GPR30 in endothelium and vascular smooth muscle (VSM), which trigger downstream signaling pathways and lead to genomic and non-genomic vascular effects such as vasodilation, decreased VSM contraction and growth and reduced vascular remodeling. However, randomized clinical trials (RCTs), such as the Women's Health Initiative (WHI) and Heart and Estrogen/progestin Replacement Study (HERS), have shown little vascular benefits and even adverse events with menopausal hormone therapy (MHT), likely due to factors related to the MHT used, ER profile, and RCT design. Some MHT forms, dose, combinations or route of administration may have inadequate vascular effects. Age-related changes in ER amount, distribution, integrity and post-ER signaling could alter the vascular response to MHT. The subject's age, preexisting CVD, and hormone environment could also reduce the effects of MHT. Further evaluation of natural and synthetic estrogens, phytoestrogens, and selective estrogen-receptor modulators (SERMs), and the design of appropriate MHT combinations, dose, route and 'timing' could improve the effectiveness of conventional MHT and provide alternative therapies in the peri-menopausal period. Targeting ER using specific ER agonists, localized MHT delivery, and activation of specific post-ER signaling pathways could counter age-related changes in ER. Examination of the hormone environment and conditions associated with hormone imbalance such as polycystic ovary syndrome may reveal the causes of abnormal hormone-receptor interactions. Consideration of these factors in new RCTs such as the Kronos Early Estrogen Prevention Study (KEEPS) could enhance the vascular benefits of estrogen in postmenopausal CVD. Copyright © 2013 Elsevier Inc. All rights reserved.

Estrogen, Vascular Estrogen Receptor and Hormone Therapy in Postmenopausal Vascular Disease

PubMed Central

Khalil, Raouf A.

2013-01-01

Cardiovascular disease (CVD) is less common in premenopausal women than men of the same age or postmenopausal women, suggesting vascular benefits of estrogen. Estrogen activates estrogen receptors ERα, ERβ and GPR30 in endothelium and vascular smooth muscle (VSM), which trigger downstream signaling pathways and lead to genomic and non-genomic vascular effects such as vasodilation, decreased VSM contraction and growth and reduced vascular remodeling. However, randomized clinical trials (RCTs), such as the Women’s Health Initiative (WHI) and Heart and Estrogen/progestin Replacement Study (HERS), have shown little vascular benefits and even adverse events with menopausal hormone therapy (MHT), likely due to factors related to the MHT used, ER profile, and RCT design. Some MHT forms, dose, combinations or route of administration may have inadequate vascular effects. Age-related changes in ER amount, distribution, integrity and post-ER signaling could alter the vascular response to MHT. The subject’s age, preexisting CVD, and hormone environment could also reduce the effects of MHT. Further evaluation of natural and synthetic estrogens, phytoestrogens, and selective estrogen-receptor modulators (SERMs), and the design of appropriate MHT combinations, dose, route and 'timing' could improve the effectiveness of conventional MHT and provide alternative therapies in the peri-menopausal period. Targeting ER using specific ER agonists, localized MHT delivery, and activation of specific post-ER signaling pathways could counter age-related changes in ER. Examination of the hormone environment and conditions associated with hormone imbalance such as polycystic ovary syndrome may reveal the causes of abnormal hormone-receptor interactions. Consideration of these factors in new RCTs such as the Kronos Early Estrogen Prevention Study (KEEPS) could enhance the vascular benefits of estrogen in postmenopausal CVD. PMID:24099797

Estrogen and female reproductive tract innervation: cellular and molecular mechanisms of autonomic neuroplasticity

PubMed Central

Brauer, M. Mónica; Smith, Peter G.

2014-01-01

The female reproductive tract undergoes remarkable functional and structural changes associated with cycling, conception and pregnancy, and it is likely advantageous to both individual and species to alter relationships between reproductive tissues and innervation. For several decades, it has been appreciated that the mammalian uterus undergoes massive sympathetic axon depletion in late pregnancy, possibly representing an adaptation to promote smooth muscle quiescence and sustained blood flow. Innervation to other structures such as cervix and vagina also undergo pregnancy-related changes in innervation that may facilitate parturition. These tissues provide highly tractable models for examining cellular and molecular mechanisms underlying peripheral nervous system plasticity. Studies show that estrogen elicits rapid degeneration of sympathetic terminal axons in myometrium, which regenerate under low-estrogen conditions. Degeneration is mediated by the target tissue: under estrogen's influence, the myometrium produces proteins repulsive to sympathetic axons including BDNF, neurotrimin, semaphorins, and pro-NGF, and extracellular matrix components are remodeled. Interestingly, nerve depletion does not involve diminished levels of classical sympathetic neurotrophins that promote axon growth. Estrogen also affects sympathetic neuron neurotrophin receptor expression in ways that appear to favor pro-degenerative effects of the target tissue. In contrast to the uterus, estrogen depletes vaginal autonomic and nociceptive axons, with the latter driven in part by estrogen-induced suppression BMP4 synthesis. These findings illustrate that hormonally mediated physiological plasticity is a highly complex phenomenon involving multiple, predominantly repulsive target-derived factors acting in concert to achieve rapid and selective reductions in innervation. PMID:25530517

EPO-independent functional EPO receptor in breast cancer enhances estrogen receptor activity and promotes cell proliferation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Reinbothe, Susann; Larsson, Anna-Maria; Vaapil, Marica

Highlights: • New anti-human EPOR antibody confirms full-length EPOR expression in breast cancer cells. • Proliferation of breast cancer cells is not affected by rhEPO treatment in vitro. • EPOR knockdown impairs proliferation of ERa positive breast cancer cells. • EPOR knockdown reduces AKT phosphorylation and ERa activity. - Abstract: The main function of Erythropoietin (EPO) and its receptor (EPOR) is the stimulation of erythropoiesis. Recombinant human EPO (rhEPO) is therefore used to treat anemia in cancer patients. However, clinical trials have indicated that rhEPO treatment might promote tumor progression and has a negative effect on patient survival. In addition,more » EPOR expression has been detected in several cancer forms. Using a newly produced anti-EPOR antibody that reliably detects the full-length isoform of the EPOR we show that breast cancer tissue and cells express the EPOR protein. rhEPO stimulation of cultured EPOR expressing breast cancer cells did not result in increased proliferation, overt activation of EPOR (receptor phosphorylation) or a consistent activation of canonical EPOR signaling pathway mediators such as JAK2, STAT3, STAT5, or AKT. However, EPOR knockdown experiments suggested functional EPO receptors in estrogen receptor positive (ERα{sup +}) breast cancer cells, as reduced EPOR expression resulted in decreased proliferation. This effect on proliferation was not seen in ERα negative cells. EPOR knockdown decreased ERα activity further supports a mechanism by which EPOR affects proliferation via ERα-mediated mechanisms. We show that EPOR protein is expressed in breast cancer cells, where it appears to promote proliferation by an EPO-independent mechanism in ERα expressing breast cancer cells.« less

Bisphenol A and Related Alkylphenols Exert Nongenomic Estrogenic Actions Through a G Protein-Coupled Estrogen Receptor 1 (Gper)/Epidermal Growth Factor Receptor (Egfr) Pathway to Inhibit Meiotic Maturation of Zebrafish Oocytes.

PubMed

Fitzgerald, Amanda C; Peyton, Candace; Dong, Jing; Thomas, Peter

2015-12-01

Xenobiotic estrogens, such as bisphenol A (BPA), disrupt a wide variety of genomic estrogen actions, but their nongenomic estrogen actions remain poorly understood. We investigated nongenomic estrogenic effects of low concentrations of BPA and three related alkylphenols on the inhibition of zebrafish oocye maturation (OM) mediated through a G protein-coupled estrogen receptor 1 (Gper)-dependent epidermal growth factor receptor (Egfr) pathway. BPA (10-100 nM) treatment for 3 h mimicked the effects of estradiol-17beta (E2) and EGF, decreasing spontaneous maturation of defolliculated zebrafish oocytes, an effect not blocked by coincubation with actinomycin D, but blocked by coincubation with a Gper antibody. BPA displayed relatively high binding affinity (15.8% that of E2) for recombinant zebrafish Gper. The inhibitory effects of BPA were attenuated by inhibition of upstream regulators of Egfr, intracellular tyrosine kinase (Src) with PP2, and matrix metalloproteinase with ilomastat. Treatment with an inhibitor of Egfr transactivation, AG1478, and an inhibitor of the mitogen-activated protein kinase (MAPK) 3/1 pathway, U0126, increased spontaneous OM and blocked the inhibitory effects of BPA, E2, and the selective GPER agonist, G-1. Western blot analysis showed that BPA (10-200 nM) mimicked the stimulatory effects of E2 and EGF on Mapk3/1 phosphorylation. Tetrabromobisphenol A, 4-nonylphenol, and tetrachlorobisphenol A (5-100 nM) also inhibited OM, an effect blocked by cotreatment with AG1478, as well as with the GPER antagonist, G-15, and displayed similar binding affinities as BPA to zebrafish Gper. The results suggest that BPA and related alkylphenols disrupt zebrafish OM by a novel nongenomic estrogenic mechanism involving activation of the Gper/Egfr/Mapk3/1 pathway. © 2015 by the Society for the Study of Reproduction, Inc.

Twenty years of the G protein-coupled estrogen receptor GPER: Historical and personal perspectives.

PubMed

Barton, Matthias; Filardo, Edward J; Lolait, Stephen J; Thomas, Peter; Maggiolini, Marcello; Prossnitz, Eric R

2018-02-01

Estrogens play a critical role in many aspects of physiology, particularly female reproductive function, but also in pathophysiology, and are associated with protection from numerous diseases in premenopausal women. Steroids and the effects of estrogen have been known for ∼90 years, with the first evidence for a receptor for estrogen presented ∼50 years ago. The original ancestral steroid receptor, extending back into evolution more than 500 million years, was likely an estrogen receptor, whereas G protein-coupled receptors (GPCRs) trace their origins back into history more than one billion years. The classical estrogen receptors (ERα and ERβ) are ligand-activated transcription factors that confer estrogen sensitivity upon many genes. It was soon apparent that these, or novel receptors may also be responsible for the "rapid"/"non-genomic" membrane-associated effects of estrogen. The identification of an orphan GPCR (GPR30, published in 1996) opened a new field of research with the description in 2000 that GPR30 expression is required for rapid estrogen signaling. In 2005-2006, the field was greatly stimulated by two studies that described the binding of estrogen to GPR30-expressing cell membranes, followed by the identification of a GPR30-selective agonist (that lacked binding and activity towards ERα and ERβ). Renamed GPER (G protein-coupled estrogen receptor) by IUPHAR in 2007, the total number of articles in PubMed related to this receptor recently surpassed 1000. In this article, the authors present personal perspectives on how they became involved in the discovery and/or advancement of GPER research. These areas include non-genomic effects on vascular tone, receptor cloning, molecular and cellular biology, signal transduction mechanisms and pharmacology of GPER, highlighting the roles of GPER and GPER-selective compounds in diseases such as obesity, diabetes, and cancer and the obligatory role of GPER in propagating cardiovascular aging, arterial

GPER mediates differential effects of estrogen on colon cancer cell proliferation and migration under normoxic and hypoxic conditions

PubMed Central

Bustos, Viviana; Nolan, Áine M.; Nijhuis, Anke; Harvey, Harry; Parker, Alexandra; Poulsom, Richard; McBryan, Jean; Thomas, Warren; Silver, Andrew; Harvey, Brian J.

2017-01-01

The estrogen receptor ERβ is the predominant ER subtype expressed in normal well-differentiated colonic epithelium. However, ERβ expression is lost under the hypoxic microenvironment as colorectal cancer (CRC) malignancy progresses. This raises questions about the role of signalling through other estrogen receptors such as ERα or G-protein coupled estrogen receptor (GPER, GPR30) by the estrogen 17β-estradiol (E2) under hypoxic conditions after ERβ is lost in CRC progression. We tested the hypothesis that E2 or hypoxia can act via GPER to contribute to the altered phenotype of CRC cells. GPER expression was found to be up-regulated by hypoxia and E2 in a panel of CRC cell lines. The E2-modulated gene, Ataxia telangiectasia mutated (ATM), was repressed in hypoxia via GPER signalling. E2 treatment enhanced hypoxia-induced expression of HIF1-α and VEGFA, but repressed HIF1-α and VEGFA expression under normoxic conditions. The expression and repression of VEGFA by E2 were mediated by a GPER-dependent mechanism. E2 treatment potentiated hypoxia-induced CRC cell migration and proliferation, whereas in normoxia, cell migration and proliferation were suppressed by E2 treatment. The effects of E2 on these cellular responses in normoxia and hypoxia were mediated by GPER. In a cohort of 566 CRC patient tumor samples, GPER expression significantly associated with poor survival in CRC Stages 3-4 females but not in the stage-matched male population. Our findings support a potentially pro-tumorigenic role for E2 in ERβ-negative CRC under hypoxic conditions transduced via GPER and suggest a novel route of therapeutic intervention through GPER antagonism. PMID:29137421

GPER mediates differential effects of estrogen on colon cancer cell proliferation and migration under normoxic and hypoxic conditions.

PubMed

Bustos, Viviana; Nolan, Áine M; Nijhuis, Anke; Harvey, Harry; Parker, Alexandra; Poulsom, Richard; McBryan, Jean; Thomas, Warren; Silver, Andrew; Harvey, Brian J

2017-10-13

The estrogen receptor ERβ is the predominant ER subtype expressed in normal well-differentiated colonic epithelium. However, ERβ expression is lost under the hypoxic microenvironment as colorectal cancer (CRC) malignancy progresses. This raises questions about the role of signalling through other estrogen receptors such as ERα or G-protein coupled estrogen receptor (GPER, GPR30) by the estrogen 17β-estradiol (E2) under hypoxic conditions after ERβ is lost in CRC progression. We tested the hypothesis that E2 or hypoxia can act via GPER to contribute to the altered phenotype of CRC cells. GPER expression was found to be up-regulated by hypoxia and E2 in a panel of CRC cell lines. The E2-modulated gene, Ataxia telangiectasia mutated ( ATM ), was repressed in hypoxia via GPER signalling. E2 treatment enhanced hypoxia-induced expression of HIF1-α and VEGFA, but repressed HIF1-α and VEGFA expression under normoxic conditions. The expression and repression of VEGFA by E2 were mediated by a GPER-dependent mechanism. E2 treatment potentiated hypoxia-induced CRC cell migration and proliferation, whereas in normoxia, cell migration and proliferation were suppressed by E2 treatment. The effects of E2 on these cellular responses in normoxia and hypoxia were mediated by GPER. In a cohort of 566 CRC patient tumor samples, GPER expression significantly associated with poor survival in CRC Stages 3-4 females but not in the stage-matched male population. Our findings support a potentially pro-tumorigenic role for E2 in ERβ-negative CRC under hypoxic conditions transduced via GPER and suggest a novel route of therapeutic intervention through GPER antagonism.

Relaxant Effects of the Selective Estrogen Receptor Modulator, Bazedoxifene, and Estrogen Receptor Agonists in Isolated Rabbit Basilar Artery.

PubMed

Castelló-Ruiz, María; Salom, Juan B; Fernández-Musoles, Ricardo; Burguete, María C; López-Morales, Mikahela A; Arduini, Alessandro; Jover-Mengual, Teresa; Hervás, David; Torregrosa, Germán; Alborch, Enrique

2016-10-01

We have previously shown that the selective estrogen receptor modulator, bazedoxifene, improves the consequences of ischemic stroke. Now we aimed to characterize the effects and mechanisms of action of bazedoxifene in cerebral arteries. Male rabbit isolated basilar arteries were used for isometric tension recording and quantitative polymerase chain reaction. Bazedoxifene relaxed cerebral arteries, as 17-β-estradiol, 4,4',4″-(4-propyl-[1H]-pyrazole-1,3,5-triyl)trisphenol [estrogen receptor (ER) α agonist], and G1 [G protein-coupled ER (GPER) agonist] did it (4,4',4″-(4-propyl-[1H]-pyrazole-1,3,5-triyl)trisphenol > bazedoxifene = G1 > 17-β-estradiol). 2,3-Bis(4-hydroxyphenyl)-propionitrile (ERβ agonist) had no effect. Expression profile of genes encoding for ERα (ESR1), ERβ (ESR2), and GPER was GPER > ESR1 > ESR2. As to the endothelial mechanisms, endothelium removal, N-nitro-L-arginine methyl ester, and indomethacin, did not modify the relaxant responses to bazedoxifene. As to the K channels, both a high-K medium and the Kv blocker, 4-aminopyridine, inhibited the bazedoxifene-induced relaxations, whereas tetraethylammonium (nonselective K channel blocker), glibenclamide (selective KATP blocker) or iberiotoxin (selective KCa blocker) were without effect. Bazedoxifene also inhibited both Ca- and Bay K8644-elicited contractions. Therefore, bazedoxifene induces endothelium-independent relaxations of cerebral arteries through (1) activation of GPER and ERα receptors; (2) increase of K conductance through Kv channels; and (3) inhibition of Ca entry through L-type Ca channels. Such a profile is compatible with the beneficial effects of estrogenic compounds (eg, SERMs) on vascular function and, specifically, that concerning the brain. Therefore, bazedoxifene could be useful in the treatment of cerebral disorders in which the cerebrovascular function is compromised (eg, stroke).

The novel estrogen receptor G-protein-coupled receptor 30 is expressed in human bone.

PubMed

Heino, Terhi J; Chagin, Andrei S; Sävendahl, Lars

2008-05-01

Estrogens have significant impact on bone mineral metabolism. Besides the classical estrogen receptors (ERalpha and ERbeta), a trans-membrane G-protein-coupled receptor (GPR30) has been demonstrated to mediate estrogenic effects. We aimed to study whether GPR30 is expressed in bone cells and if so, whether the level of expression is developmentally regulated. Metaphyseal bone biopsies were collected from the tibia in 14 boys and 6 girls, all at different stages of puberty. GPR30 protein expression was studied by immunohistochemistry in paraffin-embedded sections. GPR30-positive osteocytes and osteoblasts were quantified and linear regression analysis was applied. Cytoplasmic GPR30 expression was detected in osteoblasts, osteocytes, and osteoclasts. Osteocytes were more frequently positive for GPR30 than osteoblasts (58+/-4% vs 46+/-3% positive cells respectively, P<0.05). Detailed analysis demonstrated that GPR30 positivity declined during pubertal development in osteocytes (R=-0.56, P<0.01) but not in osteoblasts (R=-0.31, P>0.05). No sex difference was observed in the numbers of GPR30-positive osteoblasts or osteocytes. Furthermore, GPR30 expression did not correlate with chronological or bone age. In conclusion, the novel ER GPR30 is expressed in osteoblasts, osteocytes, and osteoclasts suggesting that non-genomic estrogen signaling via GPR30 may exist in bone. However, the functional role of GPR30 in bone tissue remains to be elucidated.

Expression of Genomic Functional Estrogen Receptor 1 in Mouse Sertoli Cells

PubMed Central

Lin, Jing; Zhu, Jia; Li, Xian; Li, Shengqiang; Lan, Zijian; Ko, Jay

2014-01-01

There is no consensus whether Sertoli cells express estrogen receptor 1 (Esr1). Reverse transcription-polymerase chain reaction, Western blot, and immunofluorescence demonstrated that mouse Sertoli cell lines, TM4, MSC-1, and 15P-1, and purified primary mouse Sertoli cells (PSCs) contained Esr1 messenger RNA and proteins. Incubation of Sertoli cells with 17β-estradiol (E2) or ESR1 agonist stimulated the expression of an estrogen responsive gene Greb1, which was prevented by ESR inhibitor or ESR1 antagonist. Overexpression of Esr1 in MSC-1 enhanced E2-induced Greb1 expression, while knockdown of Esr1 by small interfering RNA in TM4 attenuated the response. Furthermore, E2-induced Greb1 expression was abolished in the PSCs isolated from Amh-Cre/Esr1-floxed mice in which Esr1 in Sertoli cells were selectively deleted. Chromatin immunoprecipitation assays indicated that E2-induced Greb1 expression in Sertoli cells was mediated by binding of ESR1 to estrogen responsive elements. In summary, ligand-dependent nuclear ESR1 was present in mouse Sertoli cells and mediates a classical genomic action of estrogens. PMID:24615934

Formononetin upregulates nitric oxide synthase in arterial endothelium through estrogen receptors and MAPK pathways.

PubMed

Sun, Tao; Cao, Lei; Ping, Na-Na; Wu, Yue; Liu, Dong-Zheng; Cao, Yong-Xiao

2016-03-01

Formononetin, a phytoestrogen, can improve arterial endothelial cell function by upregulating endothelial nitric oxide synthase (eNOS). The estrogen receptor plays an important role in the regulation of eNOS. This study investigated the hypothesis that formononetin upregulates eNOS through estrogen receptors and MAPK pathways. The rat superior mesenteric arteries were cultured with formononetin or formononetin plus inhibitors for 24 h. The isometric tension of the arteries was measured using a myograph system. The mRNA and protein expression levels of eNOS were determined by real-time PCR and immunohistochemistry, respectively. Acetylcholine (ACh) relaxed the mesenteric arteries precontracted with 5-hydroxytryptamine. This relaxation could be enhanced by formononetin. The removal of endothelium or incubation with l-NAME (a NOS inhibitor) completely abolished the formononetin-enhanced relaxation induced by ACh, suggesting that the formononetin-enhanced vasodilatation is dependent on endothelium and NO pathway. The estrogen receptor inhibitor ICI 182780 attenuated the formononetin-enhanced vasodilatation induced by ACh, suggesting that the formononetin-enhanced arterial relaxation is mediated by the estrogen receptor. Formononetin increased the mRNA and protein expression levels of eNOS. ICI 182780, U0126 (an ERK1/2 inhibitor) and SP600125 (a JNK inhibitor) prevented the increases in arterial relaxation and eNOS levels. Formononetin upregulates eNOS expression in mesenteric arteries via estrogen receptors, ERK1/2 and JNK pathways. © 2016 Royal Pharmaceutical Society, Journal of Pharmacy and Pharmacology.

Maternal Regulation of Estrogen Receptor α Methylation

PubMed Central

Champagne, Frances A.; Curley, James P.

2008-01-01

Summary Advances in molecular biology have provided tools for studying the epigenetic factors which modulate gene expression. DNA methylation is an epigenetic modification which can have sustained effects on transcription and is associated with long-term gene silencing. In this review, we focus on the regulation of estrogen receptor alpha (ERα) expression by hormonal and environmental cues, the consequences of these cues for female maternal and sexual behavior and recent studies which explore the role of DNA methylation in mediating these developmental effects, with particular focus on the mediating role of maternal care. The methylation status of ERα has implications for reproductive behavior, cancer susceptibility and recovery from ischemic injury suggesting an epigenetic basis for risk and resilience across the life span. PMID:18644464

Estrogen receptor ESR1 mediates activation of ERK1/2, CREB, and ELK1 in the corpus of the epididymis.

PubMed

Cavalcanti, Fernanda N; Lucas, Thais F G; Lazari, Maria Fatima M; Porto, Catarina S

2015-06-01

Expression of the estrogen receptor ESR1 is higher in the corpus than it is in the initial segment/caput and cauda of the epididymis. ESR1 immunostaining in the corpus has been localized not only in the nuclei but also in the cytoplasm and apical membrane, which indicates that ESR1 plays a role in membrane-initiated signaling. The present study investigated whether ESR1 mediates the activation of rapid signaling pathways by estradiol (E2) in the epididymis. We investigated the effect of E2 and the ESR1-selective agonist (4,4',4''-(4-propyl-(1H)-pyrazole-1,3,5-triyl)trisphenol (PPT) on the activation of extracellular signal-regulated protein kinases (ERK1/2), CREB protein, and ETS oncogene-related protein (ELK1). Treatment with PPT did not affect ERK1/2 phosphorylation in the cauda, but it rapidly increased ERK1/2 phosphorylation in the initial segment/caput and corpus of the epididymis. PPT also activated CREB and ELK1 in the corpus of the epididymis. The PPT-induced phosphorylation of ERK1/2, CREB, and ELK1 was blocked by the ESR1-selective antagonist MPP and by pretreatment with a non-receptor tyrosine kinase SRC inhibitor, an EGFR kinase inhibitor, an MEK1/2 inhibitor, and a phosphatidylinositol-3-kinase inhibitor. In conclusion, these results indicate that the corpus, which is a region with high expression of the estrogen receptor ESR1, is a major target in the epididymis for the activation of rapid signaling by E2. The sequence of events that follow E2 interaction with ESR1 includes the SRC-mediated transactivation of EGFR and the phosphorylation of ERK1/2, CREB, and ELK1. This rapid estrogen signaling may modulate gene expression in the corpus of the epididymis, and it may play a role in the dynamic microenvironment of the epididymal lumen. © 2015 Society for Endocrinology.

Bisphenol A and Related Alkylphenols Exert Nongenomic Estrogenic Actions Through a G Protein-Coupled Estrogen Receptor 1 (Gper)/Epidermal Growth Factor Receptor (Egfr) Pathway to Inhibit Meiotic Maturation of Zebrafish Oocytes1

PubMed Central

Fitzgerald, Amanda C.; Peyton, Candace; Dong, Jing; Thomas, Peter

2015-01-01

Xenobiotic estrogens, such as bisphenol A (BPA), disrupt a wide variety of genomic estrogen actions, but their nongenomic estrogen actions remain poorly understood. We investigated nongenomic estrogenic effects of low concentrations of BPA and three related alkylphenols on the inhibition of zebrafish oocye maturation (OM) mediated through a G protein-coupled estrogen receptor 1 (Gper)-dependent epidermal growth factor receptor (Egfr) pathway. BPA (10–100 nM) treatment for 3 h mimicked the effects of estradiol-17beta (E2) and EGF, decreasing spontaneous maturation of defolliculated zebrafish oocytes, an effect not blocked by coincubation with actinomycin D, but blocked by coincubation with a Gper antibody. BPA displayed relatively high binding affinity (15.8% that of E2) for recombinant zebrafish Gper. The inhibitory effects of BPA were attenuated by inhibition of upstream regulators of Egfr, intracellular tyrosine kinase (Src) with PP2, and matrix metalloproteinase with ilomastat. Treatment with an inhibitor of Egfr transactivation, AG1478, and an inhibitor of the mitogen-activated protein kinase (MAPK) 3/1 pathway, U0126, increased spontaneous OM and blocked the inhibitory effects of BPA, E2, and the selective GPER agonist, G-1. Western blot analysis showed that BPA (10–200 nM) mimicked the stimulatory effects of E2 and EGF on Mapk3/1 phosphorylation. Tetrabromobisphenol A, 4-nonylphenol, and tetrachlorobisphenol A (5–100 nM) also inhibited OM, an effect blocked by cotreatment with AG1478, as well as with the GPER antagonist, G-15, and displayed similar binding affinities as BPA to zebrafish Gper. The results suggest that BPA and related alkylphenols disrupt zebrafish OM by a novel nongenomic estrogenic mechanism involving activation of the Gper/Egfr/Mapk3/1 pathway. PMID:26490843

Estrogen-related receptor β (ERRβ) – renaissance receptor or receptor renaissance?

PubMed Central

Divekar, Shailaja D.; Tiek, Deanna M.; Fernandez, Aileen; Riggins, Rebecca B.

2016-01-01

Estrogen-related receptors (ERRs) are founding members of the orphan nuclear receptor (ONR) subgroup of the nuclear receptor superfamily. Twenty-seven years of study have yet to identify cognate ligands for the ERRs, though they have firmly placed ERRα and ERRγ at the intersection of cellular metabolism and oncogenesis. The pace of discovery for novel functions of ERRβ, however, has until recently been somewhat slower than that of its family members. ERRβ has also been largely ignored in summaries and perspectives of the ONR literature. Here, we provide an overview of established and emerging knowledge of ERRβ in mouse, man, and other species, highlighting unique aspects of ERRβ biology that set it apart from the other two estrogen-related receptors, with a focus on the impact of alternative splicing on the structure and function of this receptor. PMID:27507929

CITED2 modulates estrogen receptor transcriptional activity in breast cancer cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lau, Wen Min; Doucet, Michele; Huang, David

2013-07-26

Highlights: •The effects of elevated CITED2 on ER function in breast cancer cells are examined. •CITED2 enhances cell growth in the absence of estrogen and presence of tamoxifen. •CITED2 functions as a transcriptional co-activator of ER in breast cancer cells. -- Abstract: Cbp/p300-interacting transactivator with Glu/Asp-rich carboxy-terminal domain 2 (CITED2) is a member of the CITED family of non-DNA binding transcriptional co-activators of the p300/CBP-mediated transcription complex. Previously, we identified CITED2 as being overexpressed in human breast tumors relative to normal mammary epithelium. Upon further investigation within the estrogen receptor (ER)-positive subset of these breast tumor samples, we found thatmore » CITED2 mRNA expression was elevated in those associated with poor survival. In light of this observation, we investigated the effect of elevated CITED2 levels on ER function. While ectopic overexpression of CITED2 in three ER-positive breast cancer cell lines (MCF-7, T47D, and CAMA-1) did not alter cell proliferation in complete media, growth was markedly enhanced in the absence of exogenous estrogen. Correspondingly, cells overexpressing CITED2 demonstrated reduced sensitivity to the growth inhibitory effects of the selective estrogen receptor modulator, 4-hydroxytamoxifen. Subsequent studies revealed that basal ER transcriptional activity was elevated in CITED2-overexpressing cells and was further increased upon the addition of estrogen. Similarly, basal and estrogen-induced expression of the ER-regulated genes trefoil factor 1 (TFF1) and progesterone receptor (PGR) was higher in cells overexpressing CITED2. Concordant with this observation, ChIP analysis revealed higher basal levels of CITED2 localized to the TFF-1 and PGR promoters in cells with ectopic overexpression of CITED2, and these levels were elevated further in response to estrogen stimulation. Taken together, these data indicate that CITED2 functions as a

G Protein-Coupled Estrogen Receptor in Energy Homeostasis and Obesity Pathogenesis

PubMed Central

Shi, Haifei; Dharshan Senthil Kumar, Shiva Priya; Liu, Xian

2013-01-01

Obesity and its related metabolic diseases have reached a pandemic level worldwide. There are sex differences in the prevalence of obesity and its related metabolic diseases, with men being more vulnerable than women; however, the prevalence of these disorders increases dramatically in women after menopause, suggesting that sex steroid hormone estrogens play key protective roles against development of obesity and metabolic diseases. Estrogens are important regulators of several aspects of metabolism, including body weight and body fat, caloric intake and energy expenditure, and glucose and lipid metabolism in both males and females. Estrogens act in complex ways on their nuclear estrogen receptors (ERs) ERα and ERβ and transmembrane ERs such as G protein-coupled estrogen receptor. Genetic tools, such as different lines of knockout mouse models, and pharmacological agents, such as selective agonists and antagonists, are available to study function and signaling mechanisms of ERs. We provide an overview of the evidence for the physiological and cellular actions of ERs in estrogen-dependent processes in the context of energy homeostasis and body fat regulation and discuss its pathology that leads to obesity and related metabolic states. PMID:23317786

Estrogen, Angiogenesis, Immunity and Cell Metabolism: Solving the Puzzle.

PubMed

Trenti, Annalisa; Tedesco, Serena; Boscaro, Carlotta; Trevisi, Lucia; Bolego, Chiara; Cignarella, Andrea

2018-03-15

Estrogen plays an important role in the regulation of cardiovascular physiology and the immune system by inducing direct effects on multiple cell types including immune and vascular cells. Sex steroid hormones are implicated in cardiovascular protection, including endothelial healing in case of arterial injury and collateral vessel formation in ischemic tissue. Estrogen can exert potent modulation effects at all levels of the innate and adaptive immune systems. Their action is mediated by interaction with classical estrogen receptors (ERs), ERα and ERβ, as well as the more recently identified G-protein coupled receptor 30/G-protein estrogen receptor 1 (GPER1), via both genomic and non-genomic mechanisms. Emerging data from the literature suggest that estrogen deficiency in menopause is associated with an increased potential for an unresolved inflammatory status. In this review, we provide an overview through the puzzle pieces of how 17β-estradiol can influence the cardiovascular and immune systems.

Estrogenic status modulates aryl hydrocarbon receptor - mediated hepatic gene expression and carcinogenicity

USDA-ARS?s Scientific Manuscript database

Estrogenic status is thought to influence the cancer risk in women and has been reported to affect toxicity of carcinogenic polycyclic aromatic hydrocarbons (PAHs) in animals. The objective of this study was to examine the influence of estradiol (E2) on hepatic gene expression changes mediated by 7,...

MIBE acts as antagonist ligand of both estrogen receptor α and GPER in breast cancer cells

PubMed Central

2012-01-01

Introduction The multiple biological responses to estrogens are mainly mediated by the classical estrogen receptors ERα and ERβ, which act as ligand-activated transcription factors. ERα exerts a main role in the development of breast cancer; therefore, the ER antagonist tamoxifen has been widely used although its effectiveness is limited by de novo and acquired resistance. Recently, GPR30/GPER, a member of the seven-transmembrane G protein-coupled receptor family, has been implicated in mediating the effects of estrogens in various normal and cancer cells. In particular, GPER triggered gene expression and proliferative responses induced by estrogens and even ER antagonists in hormone-sensitive tumor cells. Likewise, additional ER ligands showed the ability to bind to GPER eliciting promiscuous and, in some cases, opposite actions through the two receptors. We synthesized a novel compound (ethyl 3-[5-(2-ethoxycarbonyl-1-methylvinyloxy)-1-methyl-1H-indol-3-yl]but-2-enoate), referred to as MIBE, and investigated its properties elicited through ERα and GPER in breast cancer cells. Methods Molecular modeling, binding experiments and functional assays were performed in order to evaluate the biological action exerted by MIBE through ERα and GPER in MCF7 and SkBr3 breast cancer cells. Results MIBE displayed the ability to act as an antagonist ligand for ERα and GPER as it elicited inhibitory effects on gene transcription and growth effects by binding to both receptors in breast cancer cells. Moreover, GPER was required for epidermal growth factor receptor (EGFR) and ERK activation by EGF as ascertained by using MIBE and performing gene silencing experiments. Conclusions Our findings provide novel insights on the functional cross-talk between GPER and EGFR signaling. Furthermore, the exclusive antagonistic activity exerted by MIBE on ERα and GPER could represent an innovative pharmacological approach targeting breast carcinomas which express one or both receptors at

MIBE acts as antagonist ligand of both estrogen receptor α and GPER in breast cancer cells.

PubMed

Lappano, Rosamaria; Santolla, Maria Francesca; Pupo, Marco; Sinicropi, Maria Stefania; Caruso, Anna; Rosano, Camillo; Maggiolini, Marcello

2012-01-17

The multiple biological responses to estrogens are mainly mediated by the classical estrogen receptors ERα and ERβ, which act as ligand-activated transcription factors. ERα exerts a main role in the development of breast cancer; therefore, the ER antagonist tamoxifen has been widely used although its effectiveness is limited by de novo and acquired resistance. Recently, GPR30/GPER, a member of the seven-transmembrane G protein-coupled receptor family, has been implicated in mediating the effects of estrogens in various normal and cancer cells. In particular, GPER triggered gene expression and proliferative responses induced by estrogens and even ER antagonists in hormone-sensitive tumor cells. Likewise, additional ER ligands showed the ability to bind to GPER eliciting promiscuous and, in some cases, opposite actions through the two receptors. We synthesized a novel compound (ethyl 3-[5-(2-ethoxycarbonyl-1-methylvinyloxy)-1-methyl-1H-indol-3-yl]but-2-enoate), referred to as MIBE, and investigated its properties elicited through ERα and GPER in breast cancer cells. Molecular modeling, binding experiments and functional assays were performed in order to evaluate the biological action exerted by MIBE through ERα and GPER in MCF7 and SkBr3 breast cancer cells. MIBE displayed the ability to act as an antagonist ligand for ERα and GPER as it elicited inhibitory effects on gene transcription and growth effects by binding to both receptors in breast cancer cells. Moreover, GPER was required for epidermal growth factor receptor (EGFR) and ERK activation by EGF as ascertained by using MIBE and performing gene silencing experiments. Our findings provide novel insights on the functional cross-talk between GPER and EGFR signaling. Furthermore, the exclusive antagonistic activity exerted by MIBE on ERα and GPER could represent an innovative pharmacological approach targeting breast carcinomas which express one or both receptors at the beginning and/or during tumor

Black tea and D. candidum extracts play estrogenic activity via estrogen receptor α-dependent signaling pathway

PubMed Central

Wang, Yongsen; Sun, Jing; Zhang, Kun; Hu, Xin; Sun, Yuchu; Sheng, Jun; Fu, Xueqi

2018-01-01

In recent years, phytoestrogens have been shown as useful selective estrogen receptor modulators. The estrogen-like effects of black tea (BT) and D. candidum (DC), as well as the combination of the two herbs, have remained largely elusive. This study aims to investigate the phytoestrogenic effect of BT and DC extract, and the possible mechanism. The effects on T47D (ER+ cell line) proliferation were evaluated by using MTT assay. The S phase proportion of ER+ cells was determined by using flow cytometry. The estrogen antagonist ICI 182,780 was applied to block the ER function. The activation of ER-mediated PI3K/AKT and ERK signal pathways were observed by using western blot. Expression of ERα and PGR, as well as PS2 and Cyclin D1 were detected by using western blot and real-time quantitative PCR. Firstly, our results found that BT and DC extracts promoted cell proliferation in ER-positive cells, and this effect was ER-dependent. Besides, BT and DC extracts increased the S-phase cell number. Next, PI3K, AKT and ERK pathways below ER were activated by phytoestrogen treatment, and this activation was blocked by the ER antagonist. Moreover, prolonged BT and DC treatments increased the expression of ESR1 and PGR. Consistently, the mRNA levels of not only ESR1 and PGR but also estrogen-dependent effectors ps2 and cyclin D1, were increased by phytoestrogens and blocked by ICI 182,780. Taken Together, BT and DC extracts have phytoestrogenic effects, and this may provide new ideas and experimental basis for the development and application of phytoestrogens. PMID:29422998

Bisphenol AF and Bisphenol B Exert Higher Estrogenic Effects than Bisphenol A via G Protein-Coupled Estrogen Receptor Pathway.

PubMed

Cao, Lin-Ying; Ren, Xiao-Min; Li, Chuan-Hai; Zhang, Jing; Qin, Wei-Ping; Yang, Yu; Wan, Bin; Guo, Liang-Hong

2017-10-03

Numerous studies have indicated estrogenic disruption effects of bisphenol A (BPA) analogues. Previous mechanistic studies were mainly focused on their genomic activities on nuclear estrogen receptor pathway. However, their nongenomic effects through G protein-coupled estrogen receptor (GPER) pathway remain poorly understood. Here, using a SKBR3 cell-based fluorescence competitive binding assay, we found six BPA analogues bound to GPER directly, with bisphenol AF (BPAF) and bisphenol B (BPB) displaying much higher (∼9-fold) binding affinity than BPA. Molecular docking also demonstrated the binding of these BPA analogues to GPER. By measuring calcium mobilization and cAMP production in SKBR3 cells, we found the binding of these BPA analogues to GPER lead to the activation of subsequent signaling pathways. Consistent with the binding results, BPAF and BPB presented higher agonistic activity than BPA with the lowest effective concentration (LOEC) of 10 nM. Moreover, based on the results of Boyden chamber and wound-healing assays, BPAF and BPB displayed higher activity in promoting GPER mediated SKBR3 cell migration than BPA with the LOEC of 100 nM. Overall, we found two BPA analogues BPAF and BPB could exert higher estrogenic effects than BPA via GPER pathway at nanomolar concentrations.

Tamoxifen resistance and metastasis of human breast cancer cells were mediated by the membrane-associated estrogen receptor ER-α36 signaling in vitro.

PubMed

Gu, Wenwen; Dong, Nian; Wang, Peng; Shi, Changgen; Yang, Jun; Wang, Jian

2017-04-01

The drug resistance and tumor metastasis have been the main obstacles for the longer-term therapeutic effects of tamoxifen (TAM) on estrogen receptor-positive (ER + ) breast cancer, but the mechanisms underlying the TAM resistance are still unclear. Here, we demonstrated that the membrane-associated estrogen receptor ER-α36 signaling, but not the G protein-coupled estrogen receptor 1 (GPER1) signaling, might be involved in the TAM resistance and metastasis of breast cancer cells. In this study, a model of ER + breast cancer cell MCF-7 that involves the up-regulated expression of ER-α36 and unchanged expression of ER-α66 and GPER1 was established via the removal of insulin from the cell culture medium. The mechanism of TAM resistance in the ER + breast cancer cell line MCF-7 was investigated, and the results showed that the stimulating effect of insulin on susceptibility of MCF-7 to TAM was mediated by ER-α36 and that the expression level of ER-α36 in TAM-resistant MCF-7 cells was also significantly increased. Both TAM and estradiol (E2) could promote the migration of triple negative (ER-α66 - /PR - /HER2 - ) and ER-α36 + /GPER1 + breast cancer cells MDA-MB-231. The migration of MDA-MB-231 cells was inhibited by the down-regulated intracellular expression of ER-α36 by transient transfection of specific small interfering RNA, whereas no effect of GPER1 down-regulation was observed. Meanwhile, the effect of TAM on the migration of ER-α36-down-regulated MDA-MB-231 cells was also reduced. Furthermore, it was found that TAM enhanced the distribution of integrin β1 on the cell surface but did not affect the expression of integrin β1 in MDA-MB-231 cells. Collectively, these data suggested that ER-α36 signaling might play critical roles in acquired and de novo TAM resistance and metastasis of breast cancer, and ER-α36 might present a potential biomarker of TAM resistance in the clinical diagnosis and treatment of ER + breast cancer.

A transcriptionally active estrogen receptor mutant is a novel type of dominant negative inhibitor of estrogen action.

PubMed

McInerney, E M; Ince, B A; Shapiro, D J; Katzenellenbogen, B S

1996-12-01

We have characterized a human estrogen receptor (ER) mutant, V364E, which has a single amino acid substitution in its hormone-binding domain. This ER mutant is fully active or even superactive at saturating levels of estradiol (10(-8) M E2) yet has the capacity to act as a strong dominant negative inhibitor of the wild type ER. In transient transfection assays using ER-negative Chinese hamster ovary (CHO) cells and two different estrogen response element (ERE)-containing promoter reporter genes, V364E treated with 10(-8) M E2 exhibited approximately 250% and 100% of the activity of the wild type ER with these two promoter contexts, respectively. Despite the high activity of V364E when present alone in cells, coexpression of both V364E and wild type ER causes a significant decrease in overall ER-mediated transcriptional activity. On the TATA promoter, where V364E was more inhibitory, estrogen-stimulated activity was reduced by approximately 50% at a 1:1 ratio of mutant to wild type ER expression vector, and at a 10:1 ratio, 75% of ER activity was inhibited. V364E was expressed at lower levels than wild type ER and has a approximately 40-fold lower affinity for E2 compared with wild type ER. In promoter interference assays, V364E exhibited a strict dependence upon E2 for binding to an ERE. Surprisingly, even when V364E was unable to bind to ERE DNA (i.e. either at low E2 concentration or by mutation of its DNA-binding domain), this mutant retained full dominant negative activity. This highly active ER mutant is, thus, able to repress ER-mediated transcription when the mutant and wild type ER are present together in cells, even without DNA binding. Since competition for ERE binding and the formation of inactive heterodimers cannot fully account for the dominant negative activity of V364E, it is probable that altered interactions with proteins important in ER-mediated transcription play a key role in the repression of transcription by V364E. The properties and probable

Changes in estrogen receptor signaling alters the timekeeping system in male mice.

PubMed

Blattner, Margaret S; Mahoney, Megan M

2015-11-01

Circadian rhythms are modulated by steroid hormones; however, the mechanisms of this action are not fully understood, particularly in males. In females estradiol regulates activity level, pattern of expression, and free running period (tau). We tested the hypothesis that activity level and distribution in male mice includes both classical and "non-classical" actions of estrogens at the estrogen receptor subtype 1 (ESR1). We used transgenic mice with mutations in their estrogen response pathways: ESR1 knock-out (ERKO) mice lack the ability to respond to estrogens via ESR1. "Non-classical" estrogen receptor knock-in (NERKI) mice have an inserted ESR1 receptor with a mutation in the estrogen-response-element binding domain, allowing activation via non-genomic and second messenger pathways. Gonadectomized male NERKI, ERKO, and wildtype (WT) littermates were given oil, or low or high dose estradiol and daily activity parameters were quantified. Estradiol shortened the ratio of activity in the light relative to dark (LD ratio), shortened tau, advanced the time of activity onset, and altered responsiveness to light cues administered in the late subjective night, suggesting modulation by an ESR1-independent mechanism. Estradiol treatment in NERKI but not WT males altered the timing of activity onset, LD ratio, and the behavioral response to light cues. These results may represent disruptions in the balance of genomic/nongenomic or ESR1/ESR2 signaling pathways. We also found a significant genotype effect on total activity, LD ratio, tau, and activity duration. These data provide new information about the role of ESR1-dependent and independent signaling pathways on the timekeeping system in male mice. Copyright © 2015 Elsevier B.V. All rights reserved.

Differential regulation of the human progesterone receptor gene through an estrogen response element half site and Sp1 sites.

PubMed

Petz, Larry N; Ziegler, Yvonne S; Schultz, Jennifer R; Kim, Hwajin; Kemper, J Kim; Nardulli, Ann M

2004-02-01

The progesterone receptor (PR) gene is regulated by estrogen in normal reproductive tissues and in MCF-7 human breast cancer cells. Although it is generally thought that estrogen responsiveness is mediated by interaction of the ligand-occupied estrogen receptor (ER) with estrogen response elements (EREs) in target genes, the human progesterone receptor (PR) gene lacks a palindromic ERE. Promoter A of the PR gene does, however, contain an ERE half site upstream of two adjacent Sp1 sites from +571 to +595, the +571 ERE/Sp1 site. We have examined the individual contributions of the ERE half site and the two Sp1 sites in regulating estrogen responsiveness. Transient transfection assays demonstrated that both Sp1 sites were critical for estrogen-mediated activation of the PR gene. Interestingly, rather than decreasing transcription, mutations in the ERE half site increased transcription substantially suggesting that this site plays a role in limiting transcription. Chromatin immunoprecipitation assays demonstrated that Sp1 was associated with the +571 ERE/Sp1 site in the endogenous PR gene in the absence and in the presence of estrogen, but that ERalpha was only associated with this region of the PR gene after MCF-7 cells had been treated with estrogen. Our studies provide evidence that effective regulation of transcription through the +571 ERE/Sp1 site requires the binding of ERalpha and Sp1 to their respective cis elements and the appropriate interaction of ERalpha and Sp1 with other coregulatory proteins and transcription factors.

Selective estrogen receptor modulators and risk for coronary heart disease.

PubMed

Cano, A; Hermenegildo, C; Oviedo, P; Tarín, J J

2007-04-01

Coronary heart disease (CHD) is the leading cause of death in women in most countries. Atherosclerosis is the main biological process determining CHD. Clinical data support the notion that CHD is sensitive to estrogens, but debate exists concerning the effects of the hormone on atherosclerosis and its complications. Selective estrogen receptor modulators (SERMs) are compounds capable of binding the estrogen receptor to induce a functional profile distinct from estrogens. The possibility that SERMs may shift the estrogenic balance on cardiovascular risk towards a more beneficial profile has generated interest in recent years. There is considerable information on the effects of SERMs on distinct areas that are crucial in atherogenesis. The complexity derived from the diversity of variables affecting their mechanism of action plus the differences between compounds make it difficult to delineate one uniform trend for SERMs. The present picture, nonetheless, is one where SERMs seem less powerful than estrogens in atherosclerosis protection, but more gentle with advanced forms of the disease. The recent publication of the Raloxifene Use for The Heart (RUTH) study has confirmed a neutral effect for raloxifene. Prothrombotic states may favor occlusive thrombi at sites occupied by atheromatous plaques. Platelet activation has received attention as an important determinant of arterial thrombogenesis. Although still sparse, available evidence globally suggests neutral or beneficial effects for SERMs.

The G protein-coupled receptor GPR30 inhibits proliferation of estrogen receptor-positive breast cancer cells.

PubMed

Ariazi, Eric A; Brailoiu, Eugen; Yerrum, Smitha; Shupp, Heather A; Slifker, Michael J; Cunliffe, Heather E; Black, Michael A; Donato, Anne L; Arterburn, Jeffrey B; Oprea, Tudor I; Prossnitz, Eric R; Dun, Nae J; Jordan, V Craig

2010-02-01

The G protein-coupled receptor GPR30 binds 17beta-estradiol (E(2)) yet differs from classic estrogen receptors (ERalpha and ERbeta). GPR30 can mediate E(2)-induced nongenomic signaling, but its role in ERalpha-positive breast cancer remains unclear. Gene expression microarray data from five cohorts comprising 1,250 breast carcinomas showed an association between increased GPR30 expression and ERalpha-positive status. We therefore examined GPR30 in estrogenic activities in ER-positive MCF-7 breast cancer cells using G-1 and diethylstilbestrol (DES), ligands that selectively activate GPR30 and ER, respectively, and small interfering RNAs. In expression studies, E(2) and DES, but not G-1, transiently downregulated both ER and GPR30, indicating that this was ER mediated. In Ca(2+) mobilization studies, GPR30, but not ERalpha, mediated E(2)-induced Ca(2+) responses because E(2), 4-hydroxytamoxifen (activates GPR30), and G-1, but not DES, elicited cytosolic Ca(2+) increases not only in MCF-7 cells but also in ER-negative SKBr3 cells. Additionally, in MCF-7 cells, GPR30 depletion blocked E(2)-induced and G-1-induced Ca(2+) mobilization, but ERalpha depletion did not. Interestingly, GPR30-coupled Ca(2+) responses were sustained and inositol triphosphate receptor mediated in ER-positive MCF-7 cells but transitory and ryanodine receptor mediated in ER-negative SKBr3 cells. Proliferation studies involving GPR30 depletion indicated that the role of GPR30 was to promote SKBr3 cell growth but reduce MCF-7 cell growth. Supporting this, G-1 profoundly inhibited MCF-7 cell growth, potentially via p53 and p21 induction. Further, flow cytometry showed that G-1 blocked MCF-7 cell cycle progression at the G(1) phase. Thus, GPR30 antagonizes growth of ERalpha-positive breast cancer and may represent a new target to combat this disease.

Distinct Hypothalamic Neurons Mediate Estrogenic Effects on Energy Homeostasis and Reproduction

PubMed Central

Xu, Yong; Nedungadi, Thekkethil P.; Zhu, Liangru; Sobhani, Nasim; Irani, Boman G.; Davis, Kathryn E.; Zhang, Xiaorui; Zou, Fang; Gent, Lana M.; Hahner, Lisa D.; Khan, Sohaib A.; Elias, Carol F.; Elmquist, Joel K.; Clegg, Deborah J.

2011-01-01

Summary Estrogens regulate body weight and reproduction primarily through actions on estrogen receptor-α (ERα). However, ERα-expressing cells mediating these effects are not identified. We demonstrate that brain-specific deletion of ERα in female mice causes abdominal obesity stemming from both hyperphagia and hypometabolism. Hypometabolism and abdominal obesity, but not hyperphagia, are recapitulated in female mice lacking ERα in hypothalamic steroidogenic factor-1 (SF1) neurons. In contrast, deletion of ERα in hypothalamic pro-opiomelanocortin (POMC) neurons leads to hyperphagia, without directly influencing energy expenditure or fat distribution. Further, simultaneous deletion of ERα from both SF1 and POMC neurons causes hypometabolism, hyperphagia and increased visceral adiposity. Additionally, female mice lacking ERα in SF1 neurons develop anovulation and infertility, while POMC-specific deletion of ERα inhibits negative feedback regulation of estrogens and impairs fertility in females. These results indicate that estrogens act on distinct hypothalamic ERα neurons to regulate different aspects of energy homeostasis and reproduction. PMID:21982706

Estrogen receptor-β in mitochondria: implications for mitochondrial bioenergetics and tumorigenesis.

PubMed

Liao, Tien-Ling; Tzeng, Chii-Ruey; Yu, Chao-Lan; Wang, Yi-Pei; Kao, Shu-Huei

2015-09-01

Estrogen enhances mitochondrial function by enhancing mitochondrial biogenesis and sustaining mitochondrial energy-transducing capacity. Shifts in mitochondrial bioenergetic pathways from oxidative phosphorylation to glycolysis have been hypothesized to be involved in estrogen-induced tumorigenesis. Studies have shown that mitochondria are an important target of estrogen. Estrogen receptor-β (ERβ) has been shown to localize to mitochondria in a ligand-dependent or -independent manner and can affect mitochondrial bioenergetics and anti-apoptotic signaling. However, the functional role of mitochondrial ERβ in tumorigenesis remains unclear. Clinical studies of ERβ-related tumorigenesis have shown that ERβ stimulates mitochondrial metabolism to meet the high energy demands of processes such as cell proliferation, cell survival, and transformation. Thus, in elucidating the precise role of mitochondrial ERβ in cell transformation and tumorigenesis, it will be particularly valuable to explore new approaches for the development of medical treatments targeting mitochondrial ERβ-mediated mitochondrial function and preventing apoptosis. © 2015 New York Academy of Sciences.

Signaling cross-talk between peroxisome proliferator-activated receptor/retinoid X receptor and estrogen receptor through estrogen response elements.

PubMed

Keller, H; Givel, F; Perroud, M; Wahli, W

1995-07-01

Peroxisome proliferator-activated receptors (PPARs) and retinoid X receptors (RXRs) are nuclear hormone receptors that are activated by fatty acids and 9-cis-retinoic acid, respectively. PPARs and RXRs form heterodimers that activate transcription by binding to PPAR response elements (PPREs) in the promoter of target genes. The PPREs described thus far consist of a direct tandem repeat of the AGGTCA core element with one intervening nucleotide. We show here that the vitellogenin A2 estrogen response element (ERE) can also function as a PPRE and is bound by a PPAR/RXR heterodimer. Although this heterodimer can bind to several other ERE-related palindromic response elements containing AGGTCA half-sites, only the ERE is able to confer transactivation of test reporter plasmids, when the ERE is placed either close to or at a distance from the transcription initiation site. Examination of natural ERE-containing promoters, including the pS2, very-low-density apolipoprotein II and vitellogenin A2 genes, revealed considerable differences in the binding of PPAR/RXR heterodimers to these EREs. In their natural promoter context, these EREs did not allow transcriptional activation by PPARs/RXRs. Analysis of this lack of stimulation of the vitellogenin A2 promoter demonstrated that PPARs/RXRs bind to the ERE but cannot transactivate due to a nonpermissive promoter structure. As a consequence, PPARs/RXRs inhibit transactivation by the estrogen receptor through competition for ERE binding. This is the first example of signaling cross-talk between PPAR/RXR and estrogen receptor.

PI3K in the ventromedial hypothalamic nucleus mediates estrogenic actions on energy expenditure in female mice

USDA-ARS?s Scientific Manuscript database

Estrogens act in the ventromedial hypothalamic nucleus (VMH) to regulate body weight homeostasis. However, the molecular mechanisms underlying these estrogenic effects are unknown. We show that activation of estrogen receptor-a (ERa) stimulates neural firing of VMH neurons expressing ERa, and these ...

Molecular imaging provides novel insights on estrogen receptor activity in mouse brain.

PubMed

Stell, Alessia; Belcredito, Silvia; Ciana, Paolo; Maggi, Adriana

2008-01-01

Estrogen receptors have long been known to be expressed in several brain areas in addition to those directly involved in the control of reproductive functions. Investigations in humans and in animal models suggest a strong influence of estrogens on limbic and motor functions, yet the complexity and heterogeneity of neural tissue have limited our approaches to the full understanding of estrogen activity in the central nervous system. The aim of this study was to examine the transcriptional activity of estrogen receptors in the brain of male and female mice. Exploiting the ERE-Luc reporter mouse, we set up a novel, bioluminescence-based technique to study brain estrogen receptor transcriptional activity. Here we show, for the first time, that estrogen receptors are similarly active in male and female brains and that the estrous cycle affects estrogen receptor activity in regions of the central nervous system not known to be associated with reproductive functions. Because of its reproducibility and sensitivity, this novel bioluminescence application stands as a candidate as an innovative methodology for the study and development of drugs targeting brain estrogen receptors.

Molecular Imaging Provides Novel Insights on Estrogen Receptor Activity in Mouse Brain

PubMed Central

Stell, Alessia; Belcredito, Silvia; Ciana, Paolo; Maggi, Adriana

2009-01-01

Estrogen receptors have long been known to be expressed in several brain areas in addition to those directly involved in the control of reproductive functions. Investigations in humans and in animal models suggest a strong influence of estrogens on limbic and motor functions, yet the complexity and heterogeneity of neural tissue have limited our approaches to the full understanding of estrogen activity in the central nervous system. The aim of this study was to examine the transcriptional activity of estrogen receptors in the brain of male and female mice. Exploiting the ERE-Luc reporter mouse, we set up a novel, bioluminescence-based technique to study brain estrogen receptor transcriptional activity. Here we show, for the first time, that estrogen receptors are similarly active in male and female brains and that the estrous cycle affects estrogen receptor activity in regions of the central nervous system not known to be associated with reproductive functions. Because of its reproducibility and sensitivity, this novel bioluminescence application candidates as an innovative methodology for the study and development of drugs targeting brain estrogen receptors. PMID:19123998

Estradiol coupling to human monocyte nitric oxide release is dependent on intracellular calcium transients: evidence for an estrogen surface receptor.

PubMed

Stefano, G B; Prevot, V; Beauvillain, J C; Fimiani, C; Welters, I; Cadet, P; Breton, C; Pestel, J; Salzet, M; Bilfinger, T V

1999-10-01

We tested the hypothesis that estrogen acutely stimulates constitutive NO synthase (cNOS) activity in human peripheral monocytes by acting on an estrogen surface receptor. NO release was measured in real time with an amperometric probe. 17beta-estradiol exposure to monocytes stimulated NO release within seconds in a concentration-dependent manner, whereas 17alpha-estradiol had no effect. 17beta-estradiol conjugated to BSA (E2-BSA) also stimulated NO release, suggesting mediation by a membrane surface receptor. Tamoxifen, an estrogen receptor inhibitor, antagonized the action of both 17beta-estradiol and E2-BSA, whereas ICI 182,780, a selective inhibitor of the nuclear estrogen receptor, had no effect. We further showed, using a dual emission microfluorometry in a calcium-free medium, that the 17beta-estradiol-stimulated release of monocyte NO was dependent on the initial stimulation of intracellular calcium transients in a tamoxifen-sensitive process. Leeching out the intracellular calcium stores abolished the effect of 17beta-estradiol on NO release. RT-PCR analysis of RNA obtained from the cells revealed a strong estrogen receptor-alpha amplification signal and a weak beta signal. Taken together, a physiological dose of estrogen acutely stimulates NO release from human monocytes via the activation of an estrogen surface receptor that is coupled to increases in intracellular calcium.

The Role of Hypothalamic Estrogen Receptors in Metabolic Regulation

PubMed Central

Frank, Aaron; Brown, Lynda M.; Clegg, Deborah J.

2014-01-01

Estrogens regulate key features of metabolism, including food intake, body weight, energy expenditure, insulin sensitivity, leptin sensitivity, and body fat distribution. There are two ”classical“ estrogen receptors (ERs): estrogen receptor alpha (ERS1) and estrogen receptor beta (ERS2). Human and murine data indicate ERS1 contributes to metabolic regulation more so than ESR2. For example, there are human inactivating mutations of ERS1 which recapitulate aspects of the metabolic syndrome in both men and women. Much of our understanding of the metabolic roles of ERS1 was initially uncovered in estrogen receptor α-null mice (ERS1−/−); these mice display aspects of the metabolic syndrome, including increased body weight, increased visceral fat deposition and dysregulated glucose intolerance. Recent data further implicate ERS1 in specific tissues and neuronal populations as being critical for regulating food intake, energy expenditure, body fat distribution and adipose tissue function. This review will focus predominantly on the role of hypothalamic ERs and their critical role in regulating all aspects of energy homeostasis and metabolism. PMID:24882636

The role of hypothalamic estrogen receptors in metabolic regulation.

PubMed

Frank, Aaron; Brown, Lynda M; Clegg, Deborah J

2014-10-01

Estrogens regulate key features of metabolism, including food intake, body weight, energy expenditure, insulin sensitivity, leptin sensitivity, and body fat distribution. There are two 'classical' estrogen receptors (ERs): estrogen receptor alpha (ERS1) and estrogen receptor beta (ERS2). Human and murine data indicate ERS1 contributes to metabolic regulation more so than ESR2. For example, there are human inactivating mutations of ERS1 which recapitulate aspects of the metabolic syndrome in both men and women. Much of our understanding of the metabolic roles of ERS1 was initially uncovered in estrogen receptor α-null mice (ERS1(-/-)); these mice display aspects of the metabolic syndrome, including increased body weight, increased visceral fat deposition and dysregulated glucose intolerance. Recent data further implicate ERS1 in specific tissues and neuronal populations as being critical for regulating food intake, energy expenditure, body fat distribution and adipose tissue function. This review will focus predominantly on the role of hypothalamic ERs and their critical role in regulating all aspects of energy homeostasis and metabolism. Copyright © 2014 Elsevier Inc. All rights reserved.

Estrogenic Mechanisms and Cardiac Responses Following Early Life Exposure to Bisphenol A (BPA) and Its Metabolite 4-Methyl-2,4-bis( p-hydroxyphenyl)pent-1-ene (MBP) in Zebrafish.

PubMed

Moreman, John; Takesono, Aya; Trznadel, Maciej; Winter, Matthew J; Perry, Alexis; Wood, Mark E; Rogers, Nicola J; Kudoh, Tetsuhiro; Tyler, Charles R

2018-06-05

Environmental exposure to Bisphenol A (BPA) has been associated with a range of adverse health effects, including on the cardiovascular system in humans. Lack of agreement on its mechanism(s) of action likely stem from comparisons between in vivo and in vitro test systems and potential multiple effects pathways. In rodents, in vivo, metabolic activation of BPA produces 4-methyl-2,4-bis(4-hydroxyphenyl)pent-1-ene (MBP), which is reported to be up to 1000 times more potent as an estrogen than BPA. We investigated the estrogenic effects and estrogen receptor signaling pathway(s) of BPA and MBP following early life exposure using a transgenic, estrogen responsive (ERE-TG) zebrafish and a targeted morpholino approach to knockdown the three fish estrogen receptor (ER) subtypes. The functional consequences of BPA exposure on the cardiovascular system of zebrafish larvae were also examined. The heart atrioventricular valves and the bulbus arteriosus were primary target tissues for both BPA and MBP in the ERE-TG zebrafish, and MBP was approximately 1000-fold more potent than BPA as an estrogen in these tissues. Estrogen receptor knockdown with morpholinos indicated that the estrogenic responses in the heart for both BPA and MBP were mediated via an estrogen receptor 1 (esr1) dependent pathway. At the highest BPA concentration tested (2500 μg/L), alterations in the atrial:ventricular beat ratio indicated a functional impact on the heart of 5 days post fertilization (dpf) larvae, and there was also a significantly reduced heart rate in these larvae at 14 dpf. Our findings indicate that some of the reported adverse effects on heart function associated with BPA exposure (in mammals) may act through an estrogenic mechanism, but that fish are unlikely to be susceptible to adverse effects on heart development for environmentally relevant exposures.

Insights from the Study of Animals Lacking Functional Estrogen Receptor

NASA Astrophysics Data System (ADS)

Korach, Kenneth S.

1994-12-01

Estrogen hormones produce physiological actions within a variety of target sites in the body and during development by activating a specific receptor protein. Hormone responsiveness for the estrogen receptor protein was investigated at different stages of development with the use of gene knockout techniques because no natural genetic mutants have been described. A mutant mouse line without a functional estrogen receptor was created and is being used to assess estrogen responsiveness. Both sexes of these mutant animals are infertile and show a variety of phenotypic changes, some of which are associated with the gonads, mammary glands, reproductive tracts, and skeletal tissues.

Estrogen receptors in skeletal metabolism: lessons from genetically modified models of receptor function.

PubMed

McCauley, Laurie K; Tözüm, Tolga F; Rosol, Thomas J

2002-01-01

Estrogens have long been known to be important for skeletal homeostasis, but their precise mechanisms of action in bone are still unclear. Mice with targeted deletions of the estrogen receptors alpha (ERalpha) and beta (ERbeta) have been generated by two research groups and several studies performed characterizing the phenotype of ERalpha knockout (ERKOalpha), ERbeta knockout (ERKObeta), or double deletion of ERalpha and ERbeta (DERKO) mice. Initial studies reported a reduction in bone mineral density in male ERKOalpha mice. More extensive analyses have been puzzling, likely because of compensatory mechanisms in ERKO mice. Furthermore, the existence of a third ER continues to be a potential explanation for some actions of estrogen in bone. Other rodent models, including the testicular feminized mouse and rat, the aromatase knockout mouse, and a rat with a dominant negative ER mutation, have added information regarding estrogen's actions in bone. This review summarizes many reports characterizing available rodent models with genetic alterations relevant to estrogen action. The sum of these reports suggests that the ERbeta is not highly protective in bone because loss of its function results in minimal alterations in the skeleton. Furthermore, loss of both the ERalpha and the ERbeta does not account for loss of estrogen action in bone, because the impact of DERKO is seemingly not as great as the impact of gonadectomy on the skeleton. Finally, through studies of ERKO mice and other rodent models of altered sex steroid action, it appears that estrogen may be more protective in the skeleton than androgens.

Rapid Steroid Hormone Actions Initiated at the Cell Surface and the Receptors that Mediate Them with an Emphasis on Recent Progress in Fish Models

PubMed Central

Thomas, Peter

2011-01-01

In addition to the classic genomic mechanism of steroid action mediated by activation of intracellular nuclear receptors, there is now extensive evidence that steroids also activate receptors on the cell surface to initiate rapid intracellular signaling and biological responses that are often nongenomic. Recent progress in our understanding of rapid, cell surface-initiated actions of estrogens, progestins, androgens and corticosteroids and the identities of the membrane receptors that act as their intermediaries is briefly reviewed with a special emphasis on studies in teleost fish. Two recently discovered novel proteins with seven-transmembrane domains, G protein-coupled receptor 30 (GPR30), and membrane progestin receptors (mPRs) have the ligand binding and signaling characteristics of estrogen and progestin membrane receptors, respectively, but their functional significance is disputed by some researchers. GPR30 is expressed on the cell surface of fish oocytes and mediates estrogen inhibition of oocyte maturation. mPRα is also expressed on the oocyte cell surface and is the intermediary in progestin induction of oocyte maturation in fish. Recent results suggest there is cross-talk between these two hormonal pathways and that there is reciprocal down-regulation of GPR30 and mPRα expression by estrogens and progestins at different phases of oocyte development to regulate the onset of oocyte maturation. There is also evidence in fish that mPRs are involved in progestin induction of sperm hypermotility and anti-apoptotic actions in ovarian follicle cells. Nonclassical androgen and corticosteroid actions have also been described in fish models but the membrane receptors mediating these actions have not been identified. PMID:22154643

Targeted Radiotherapy of Estrogen Receptor Positive Tumors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Raghavan Rajagopalan

The overall objectives of the proposal were to develop estrogen receptor (ER) binding small molecule radiopharmaceuticals for targeted radiotherapy of ER positive (ER+) tumors. In particular, this proposal focused on embedding a {sup 186,188}Re or a {sup 32}P radionuclide into an estrogen steroidal framework by isosteric substitution such that the resulting structure is topologically similar to the estrogen (estrogen mimic). The estrogen mimic molecules expected to bind to the ER and exhibit biodistribution akin to that of native estrogen due to structural mimicry. It is anticipated that the {sup 186,188}Re- or a {sup 32}P-containing estrogen mimics will be useful formore » targeted molecular radiotherapy of ER+ tumors. It is well established that the in vivo target tissue uptake of estrogen like steroidal molecules is related to the binding of the steroids to sex hormone binding globulin (SHBG). SHBG is important in the uptake of estrogens and testosterone in target tissues by SHBG receptors on the cell surface. However, hitherto the design of estrogen like small molecule radiopharmaceuticals was focused on optimizing ER binding characteristics without emphasis on SHBG binding properties. Consequently, even the molecules with good ER affinity in vitro, performed poorly in biodistribution studies. Based on molecular modeling studies the proposal focused on developing estrogen mimics 1-3 which were topologically similar to native estrogens, and form hydrogen bonds in ER and SHBG in the same manner as those of native estrogens. To this end the technical objectives of the proposal focused on synthesizing the rhenium-estrone and estradiol mimics 1 and 2 respectively, and phosphorous estradiol mimic 3 and to assess their stability and in vitro binding characteristics to ER and SHBG.« less

The nuclear orphan receptors COUP-TF and ARP-1 positively regulate the trout estrogen receptor gene through enhancing autoregulation.

PubMed Central

Lazennec, G; Kern, L; Valotaire, Y; Salbert, G

1997-01-01

The rainbow trout estrogen receptor (rtER) is a positively autoregulated gene in liver cells. In a previous report, we showed that upregulation is mediated by an estrogen response element (ERE) located in the proximal promoter of the gene and that a half binding site for nuclear receptors (5'-TGACCT-3') located 15 bp upstream of the ERE is involved in the magnitude of the estrogen response. We now report that the human orphan receptor COUP-TF and a COUP-TF-like protein from trout liver are able to bind to the consensus half-site. When cotransfected with the rtER gene proximal promoter, COUP-TF had no regulatory functions on its own. Interestingly, COUP-TF enhanced rtER transactivation properties in the presence of estradiol in a dose-dependent manner when cotransfected with the rtER gene promoter. Unliganded retinoid receptor heterodimers had the same helper function as COUP-TF in the presence of estradiol but were switched to repressors when the ligand all-trans-retinoic acid was added. Mutation of the consensus half-site only slightly reduced COUP-TF helper function, suggesting that it actually results from a complex mechanism that probably involves both DNA binding of COUP-TF to the promoter and protein-protein interaction with another transcription factor bound to the promoter. Nevertheless, a DNA-binding-defective mutant of COUP-TF was also defective in ER helper function. Competition footprinting analysis suggested that COUP-TF actually establishes contacts with the consensus upstream half-site and the downstream ERE half-site that would form a DR-24-like response element. Interaction of COUP-TF with the DR-24 element was confirmed in footprinting assays by using nuclear extracts from Saccharomyces cerevisiae expressing COUP-TF. Finally, interaction of COUP-TF with mutants of the rtER gene promoter showed that COUP-TF recognizes the ERE when the upstream half-site is mutated. These data show that COUP-TF may activate transcription through interaction with

Aldosterone mediates metastatic spread of renal cancer via the G protein-coupled estrogen receptor (GPER).

PubMed

Feldman, Ross D; Ding, Qingming; Hussain, Yasin; Limbird, Lee E; Pickering, J Geoffrey; Gros, Robert

2016-06-01

Although aldosterone is a known regulator of renal and cardiovascular function, its role as a regulator of cancer growth and spread has not been widely considered. This study tested the hypothesis that aldosterone regulates cancer cell growth/spread via G protein-coupled estrogen receptor (GPER) activation. In vitro in murine renal cortical adenocarcinoma (RENCA) cells, a widely used murine in vitro model for the study of renal cell adenocarcinoma, aldosterone increased RENCA cell proliferation to a maximum of 125 ± 3% of control at a concentration of 10 nM, an effect blocked by the GPER antagonist G15 or by GPER knockdown using short interfering (sh) RNA techniques. Further, aldosterone increased RENCA cell migration to a maximum of 170 ± 20% of control at a concentration of 100 nM, an effect also blocked by G15 or by GPER down-regulation. In vivo, after orthotopic RENCA cell renal transplantation, pulmonary tumor spread was inhibited by pharmacologic blockade of aldosterone effects with spironolactone (percentage of lung occupied by metastasis: control = 68 ± 13, spironolactone = 26 ± 8, P < 0.05) or inhibition of aldosterone synthesis with a high dietary salt diet (percentage of lung: control = 44 ± 6, high salt = 12 ± 3, P < 0.05), without reducing primary tumor size. Additionally, adrenalectomy significantly reduced the extent of pulmonary tumor spread, whereas aldosterone infusion recovered pulmonary metastatic spread toward baseline levels. Finally, inhibition of GPER either with the GPER antagonist G15 or by GPER knockdown comparably inhibited RENCA cell pulmonary metastatic cancer spread. Taken together, these findings provide strong evidence for aldosterone serving a causal role in renal cell cancer regulation via its GPER receptor; thus, antagonism of GPER represents a potential new target for treatment to reduce metastatic spread.-Feldman, R. D., Ding, Q., Hussain, Y., Limbird, L. E., Pickering, J. G., Gros, R. Aldosterone mediates metastatic

Estrogen receptors involvement in intervertebral discogenic pain of the elderly women: colocalization and correlation with the expression of Substance P in nucleus pulposus.

PubMed

Song, Xiao-Xing; Shi, Sheng; Guo, Zhen; Li, Xin-Feng; Yu, Bu-Wei

2017-06-13

Estrogenic modulation of pain is an exceedingly complex phenomenon. However, whether estrogen is involved in discogenic low back pain still remains unclear. Here, immunoreactivity staining technique was used to examine the expression level of the estrogen receptors (ERα and ERβ) and a pain related neuropeptide, Substance P in the lumbar intervertebral discs to analyze the relationship between the ERs and Substance P. Nucleus pulposus tissues of 23 elderly female patients were harvested during spinal surgeries and made to detect the immunoreactivity staining of ERα, ERβ and Substance P. The colocalization and intensities of ERs and Substance P were explored and evaluated respectively. The correlations between changes of ERα, ERβ and Substance P were also assessed.Our results revealed that Substance P colocalized with ERα and ERβ both in cytoplasm and nucleus of the nucleus pulposus cells. HSCORE analysis indicated that Substance P negatively correlated with both ERα and ERβ expression. Collectively, the crosstalk between ERs and Substance P might exist in the disc tissue. Estrogen-dependent pain mechanism might partly be mediated through ERs and Substance P in the nucleus pulposus of the elderly females. Estrogen and its receptors might be drug targets in discogenic low back pain diseases.

A recombinant estrogen receptor fragment-based homogeneous fluorescent assay for rapid detection of estrogens.

PubMed

Wang, Dan; Xie, Jiangbi; Zhu, Xiaocui; Li, Jinqiu; Zhao, Dongqin; Zhao, Meiping

2014-05-15

In this work, we demonstrate a novel estrogenic receptor fragment-based homogeneous fluorescent assay which enables rapid and sensitive detection of 17β-estradiol (E2) and other highly potent estrogens. A modified human estrogenic receptor fragment (N-His × 6-hER270-595-C-Strep tag II) has been constructed that contains amino acids 270-595 of wild-type human estrogenic receptor α (hER270-595) and two specific tags (6 × His and Strep tag II) fused to the N and C terminus, respectively. The designed receptor protein fragment could be easily produced by prokaryotic expression with high yield and high purity. The obtained protein exhibits high binding affinity to E2 and the two tags greatly facilitate the application of the recombinant protein. Taking advantage of the unique spectroscopic properties of coumestrol (CS), a fluorescent phytoestrogen, a CS/hER270-595-based fluorescent assay has been developed which can sensitively respond to E2 within 1.0 min with a linear working range from 0.1 to 20 ng/mL and a limit of detection of 0.1 ng/mL. The assay was successfully applied for rapid detection of E2 in the culture medium of rat hippocampal neurons. The method also holds great potential for high-throughput monitoring the variation of estrogen levels in complex biological fluids, which is crucial for investigation of the molecular basis of various estrogen-involved processes. Copyright © 2013 Elsevier B.V. All rights reserved.

Conditional expression of constitutively active estrogen receptor {alpha} in chondrocytes impairs longitudinal bone growth in mice

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ikeda, Kazuhiro; Tsukui, Tohru; Imazawa, Yukiko

2012-09-07

Highlights: Black-Right-Pointing-Pointer Conditional transgenic mice expressing constitutively active estrogen receptor {alpha} (caER{alpha}) in chondrocytes were developed. Black-Right-Pointing-Pointer Expression of caER{alpha} in chondrocytes impaired longitudinal bone growth in mice. Black-Right-Pointing-Pointer caER{alpha} affects chondrocyte proliferation and differentiation. Black-Right-Pointing-Pointer This mouse model is useful for understanding the physiological role of ER{alpha}in vivo. -- Abstract: Estrogen plays important roles in the regulation of chondrocyte proliferation and differentiation, which are essential steps for longitudinal bone growth; however, the mechanisms of estrogen action on chondrocytes have not been fully elucidated. In the present study, we generated conditional transgenic mice, designated as caER{alpha}{sup ColII}, expressing constitutively activemore » mutant estrogen receptor (ER) {alpha} in chondrocytes, using the chondrocyte-specific type II collagen promoter-driven Cre transgenic mice. caER{alpha}{sup ColII} mice showed retardation in longitudinal growth, with short bone lengths. BrdU labeling showed reduced proliferation of hypertrophic chondrocytes in the proliferating layer of the growth plate of tibia in caER{alpha}{sup ColII} mice. In situ hybridization analysis of type X collagen revealed that the maturation of hypertrophic chondrocytes was impaired in caER{alpha}{sup ColII} mice. These results suggest that ER{alpha} is a critical regulator of chondrocyte proliferation and maturation during skeletal development, mediating longitudinal bone growth in vivo.« less

Lordosis facilitated by GPER-1 receptor activation involves GnRH-1, progestin and estrogen receptors in estrogen-primed rats.

PubMed

Domínguez-Ordóñez, R; Garcia-Juárez, M; Lima-Hernández, F J; Gómora-Arrati, P; Domínguez-Salazar, E; Blaustein, J D; Etgen, A M; González-Flores, O

2018-02-01

The present study assessed the participation of membrane G-protein coupled estrogen receptor 1 (GPER-1) and gonadotropin releasing hormone 1 (GnRH-1) receptor in the display of lordosis induced by intracerebroventricular (icv) administration of G1, a GPER-1 agonist, and by unesterified 17β-estradiol (free E 2 ). In addition, we assessed the participation of both estrogen and progestin receptors in the lordosis behavior induced by G1 in ovariectomized (OVX), E 2 -benzoate (EB)-primed rats. In Experiment 1, icv injection of G1 induced lordosis behavior at 120 and 240min. In Experiment 2, icv injection of the GPER-1 antagonist G15 significantly reduced lordosis behavior induced by either G1 or free E 2 . In addition, Antide, a GnRH-1 receptor antagonist, significantly depressed G1 facilitation of lordosis behavior in OVX, EB-primed rats. Similarly, icv injection of Antide blocked the stimulatory effect of E 2 on lordosis behavior. In Experiment 3, systemic injection of either tamoxifen or RU486 significantly reduced lordosis behavior induced by icv administration of G1 in OVX, EB-primed rats. The results suggest that GnRH release activates both estrogen and progestin receptors and that this activation is important in the chain of events leading to the display of lordosis behavior in response to activation of GPER-1 in estrogen-primed rats. Copyright © 2018 Elsevier Inc. All rights reserved.

Tamoxifen induces the expression of maspin through estrogen receptor-alpha.

PubMed

Liu, Zesheng; Shi, Heidi Y; Nawaz, Zafar; Zhang, Ming

2004-06-08

Maspin (mammary serine protease inhibitor) is a tumor suppressor gene that plays an important role in inhibiting tumor growth, invasion and metastasis. Maspin expression is down regulated at transcription level in primary and metastatic breast tumor cells. Previous studies on hormonal regulation of maspin prompt us to test whether an estrogen antagonist tamoxifen (TAM) can exert its anti-tumor function by up regulating maspin gene expression. For this purpose, we first tested whether maspin promoter could be activated in normal and several breast tumor cells. We then carried out a series of promoter analysis in which estrogen receptors and TAM were reconstituted in an in vitro cell culture system. Here we report our new finding that tumor suppresser gene maspin is one of the TAM target genes. TAM induces a maspin/luciferase reporter in cell culture and this induction requires the presence of (estrogen receptor alpha) ERalpha but not estrogen receptor-beta (ERbeta). Maspin promoter deletion and mutation analysis showed that the cis element(s) within a region between -90and+87 bp but not the HRE site (-272 bp) was involved in TAM induction of maspin expression. TAM bound ERalpha may directly control maspin gene expression through the interaction with cofactor (s). Analysis using several ERalpha mutants showed that the N-terminal A/B motif (AF-1) was critical for maspin basal level transcription activation. An ERalpha mutant with point mutations at DNA binding domain abolished estrogen induction of an ERE-luciferase reporter but was still active in activating maspin promoter by TAM. LBD-AF2 domain was required for ERalpha-dependent TAM induction. Deletion of LBD-AF2 or a point mutation in the ERalpha LBD-AF2 region (LBDmtL539A) completely abolished the activation of maspin promoter, suggesting that TAM induction of maspin involves the recruitment of cofactor(s) by ERalpha to the maspin promoter region. This finding indicates that one of the pathways for cancer

Rapid effects of dorsal hippocampal G-protein coupled estrogen receptor on learning in female mice.

PubMed

Lymer, Jennifer; Robinson, Alana; Winters, Boyer D; Choleris, Elena

2017-03-01

Through rapid mechanisms of action, estrogens affect learning and memory processes. It has been shown that 17β-estradiol and an Estrogen Receptor (ER) α agonist enhances performance in social recognition, object recognition, and object placement tasks when administered systemically or infused in the dorsal hippocampus. In contrast, systemic and dorsal hippocampal ERβ activation only promote spatial learning. In addition, 17β-estradiol, the ERα and the G-protein coupled estrogen receptor (GPER) agonists increase dendritic spine density in the CA1 hippocampus. Recently, we have shown that selective systemic activation of the GPER also rapidly facilitated social recognition, object recognition, and object placement learning in female mice. Whether activation the GPER specifically in the dorsal hippocampus can also rapidly improve learning and memory prior to acquisition is unknown. Here, we investigated the rapid effects of infusion of the GPER agonist, G-1 (dose: 50nM, 100nM, 200nM), in the dorsal hippocampus on social recognition, object recognition, and object placement learning tasks in home cage. These paradigms were completed within 40min, which is within the range of rapid estrogenic effects. Dorsal hippocampal administration of G-1 improved social (doses: 50nM, 200nM G-1) and object (dose: 200nM G-1) recognition with no effect on object placement. Additionally, when spatial cues were minimized by testing in a Y-apparatus, G-1 administration promoted social (doses: 100nM, 200nM G-1) and object (doses: 50nM, 100nM, 200nM G-1) recognition. Therefore, like ERα, the GPER in the hippocampus appears to be sufficient for the rapid facilitation of social and object recognition in female mice, but not for the rapid facilitation of object placement learning. Thus, the GPER in the dorsal hippocampus is involved in estrogenic mediation of learning and memory and these effects likely occur through rapid signalling mechanisms. Copyright © 2016 Elsevier Ltd. All rights

Visualizing estrogen receptor-a-expressing neurons using a new ERa-ZsGreen reporter mouse line

USDA-ARS?s Scientific Manuscript database

A variety of biological functions of estrogens, including regulation of energy metabolism, are mediated by neurons expressingestrogen receptor-a (ERa) in the brain. However, complex intracellular processes in these ERa-expressing neurons are difficult to unravel, due to the lack of strategy to visua...

Estrogenic Environmental Chemicals and Drugs: Mechanisms for Effects on the Developing Male Urogenital System

PubMed Central

Taylor, Julia A.; Richter, Catherine A.; Ruhlen, Rachel L.; vom Saal, Frederick S.

2011-01-01

Development and differentiation of the prostate from the fetal urogenital sinus (UGS) is dependent on androgen action via androgen receptors (AR) in the UGS mesenchyme. Estrogens are not required for prostate differentiation but do act to modulate androgen action. In mice exposure to exogenous estrogen during development results in permanent effects on adult prostate size and function, which is mediated through mesenchymal estrogen receptor (ER) alpha. For many years estrogens were thought to inhibit prostate growth because estrogenic drugs studied were administered at very high concentrations that interfered with normal prostate development. There is now extensive evidence that exposure to estrogen at very low concentrations during the early stages of prostate differentiation can stimulate fetal/neonatal prostate growth and lead to prostate disease in adulthood. Bisphenol A (BPA) is an environmental endocrine disrupting chemical that binds to both ER receptor subtypes as well as to AR. Interest in BPA has increased because of its prevalence in the environment and its detection in over 90% of people in the USA. In tissue culture of fetal mouse UGS mesenchymal cells, BPA and estradiol stimulated changes in the expression of several genes. We discuss here the potential involvement of estrogen in regulating signaling pathways affecting cellular functions relevant to steroid hormone signaling and metabolism and to inter- and intra-cellular communications that promote cell growth. The findings presented here provide additional evidence that BPA and the estrogenic drug ethinylestradiol disrupt prostate development in male mice at administered doses relevant to human exposures. PMID:21827855

CERAPP: Collaborative Estrogen Receptor Activity Prediction Project

EPA Pesticide Factsheets

Data from a large-scale modeling project called CERAPP (Collaborative Estrogen Receptor Activity Prediction Project) demonstrating using predictive computational models on high-throughput screening data to screen thousands of chemicals against the estrogen receptor.This dataset is associated with the following publication:Mansouri , K., A. Abdelaziz, A. Rybacka, A. Roncaglioni, A. Tropsha, A. Varnek, A. Zakharov, A. Worth, A. Richard , C. Grulke , D. Trisciuzzi, D. Fourches, D. Horvath, E. Benfenati , E. Muratov, E.B. Wedebye, F. Grisoni, G.F. Mangiatordi, G.M. Incisivo, H. Hong, H.W. Ng, I.V. Tetko, I. Balabin, J. Kancherla , J. Shen, J. Burton, M. Nicklaus, M. Cassotti, N.G. Nikolov, O. Nicolotti, P.L. Andersson, Q. Zang, R. Politi, R.D. Beger , R. Todeschini, R. Huang, S. Farag, S.A. Rosenberg, S. Slavov, X. Hu, and R. Judson. (Environmental Health Perspectives) CERAPP: Collaborative Estrogen Receptor Activity Prediction Project. ENVIRONMENTAL HEALTH PERSPECTIVES. National Institute of Environmental Health Sciences (NIEHS), Research Triangle Park, NC, USA, 1-49, (2016).

Internalization of a C17α-alkynylestradiol-porphyrin conjugate into estrogen receptor positive MCF-7 breast cancer cells.

PubMed

Sadler, Sara; Persons, Kelly S; Jones, Graham B; Ray, Rahul

2011-08-01

We hypothesized that expression of nuclear estrogen receptor (ER) in hormone-sensitive breast cancer cells could be harnessed synergistically with the tumor-accumulating effect of porphyrins to selectively deliver estrogen-porphyrin conjugates into breast tumor cells, and preferentially kill tumor cells upon exposure to visible light. In this study we synthesized a conjugate of C(17α)-alkynylestradiol and pyropheophorbide and demonstrated that this conjugate is internalized by ER-positive MCF-7 cells while pyropheophorbide did not, suggesting an ER-mediated uptake and internalization of the conjugate by incipient nuclear ER in MCF-7 cells. This study is a direct demonstration of our hypothesis about ER-mediated internalization of estrogen-porphyrin conjugates. Copyright © 2011. Published by Elsevier Ltd.

Targeted basic research to highlight the role of estrogen and estrogen receptors in the cardiovascular system.

PubMed

Dworatzek, Elke; Mahmoodzadeh, Shokoufeh

2017-05-01

Epidemiological, clinical and animal studies revealed that sex differences exist in the manifestation and outcome of cardiovascular disease (CVD). The underlying molecular mechanisms implicated in these sex differences are not fully understood. The reasons for sex differences in CVD are definitely multifactorial, but major evidence points to the contribution of sex steroid hormone, 17β-estradiol (E2), and its receptors, estrogen receptor alpha (ERα) and estrogen receptor beta (ERβ). In this review, we summarize past and present studies that implicate E2 and ER as important determinants of sexual dimorphism in the physiology and pathophysiology of the heart. In particular, we give an overview of studies aimed to reveal the role of E2 and ER in the physiology of the observed sex differences in CVD using ER knock-out mice. Finally, we discuss recent findings from novel transgenic mouse models, which have provided new information on the sexual dimorphic roles of ER specifically in cardiomyocytes under pathological conditions. Copyright © 2017 Elsevier Ltd. All rights reserved.

Efficacy of Histone Deacetylase and Estrogen Receptor Inhibition in Breast Cancer Cells Due to Concerted down Regulation of Akt

PubMed Central

Thomas, Scott; Thurn, K. Ted; Raha, Paromita; Chen, Stephanie; Munster, Pamela N.

2013-01-01

Hormonal therapy resistance remains a considerable barrier in the treatment of breast cancer. Activation of the Akt-PI3K-mTOR pathway plays an important role in hormonal therapy resistance. Our recent preclinical and clinical studies showed that the addition of a histone deacetylase inhibitor re-sensitized hormonal therapy resistant breast cancer to tamoxifen. As histone deacetylases are key regulators of Akt, we evaluated the effect of combined treatment with the histone deacetylase inhibitor PCI-24781 and tamoxifen on Akt in breast cancer cells. We demonstrate that while both histone deacetylase and estrogen receptor inhibition down regulate AKT mRNA and protein, their concerted effort results in down regulation of AKT activity with induction of cell death. Histone deacetylase inhibition exerts its effect on AKT mRNA through an estrogen receptor-dependent mechanism, primarily down regulating the most abundant isoform AKT1. Although siRNA depletion of AKT modestly induces cell death, when combined with an anti-estrogen, cytotoxicity is significantly enhanced. Thus, histone deacetylase regulation of AKT mRNA is a key mediator of this therapeutic combination and may represent a novel biomarker for predicting response to this regimen. PMID:23874830

Estrogen directly and specifically downregulates NaPi-IIa through the activation of both estrogen receptor isoforms (ERα and ERβ) in rat kidney proximal tubule.

PubMed

Burris, Dara; Webster, Rose; Sheriff, Sulaiman; Faroqui, Rashma; Levi, Moshe; Hawse, John R; Amlal, Hassane

2015-03-15

We have previously demonstrated that estrogen (E2) downregulates phosphate transporter NaPi-IIa and causes phosphaturia and hypophosphatemia in ovariectomized rats. In the present study, we examined whether E2 directly targets NaPi-IIa in the proximal tubule (PT) and studied the respective roles of estrogen receptor isoforms (ERα and ERβ) in the downregulation of NaPi-IIa using both in vivo and an in vitro expression systems. We found that estrogen specifically downregulates NaPi-IIa but not NaPi-IIc or Pit2 in the kidney cortex. Proximal tubules incubated in a "shake" suspension with E2 for 24 h exhibited a dose-dependent decrease in NaPi-IIa protein abundance. Results from OVX rats treated with specific agonists for either ERα [4,4',4″;-(4-propyl-[1H]-pyrazole-1,3,5-triyl) trisphenol, PPT] or ERβ [4,4',4″-(4-propyl-[1H]-pyrazole-1,3,5-triyl) trisphenol, DPN] or both (PPT + DPN), indicated that only the latter caused a sharp downregulation of NaPi-IIa, along with significant phosphaturia and hypophosphatemia. Lastly, heterologous expression studies demonstrated that estrogen downregulated NaPi-IIa only in U20S cells expressing both ERα and ERβ, but not in cells expressing either receptor alone. In conclusion, these studies demonstrate that rat PT cells express both ERα and ERβ and that E2 induces phosphaturia by directly and specifically targeting NaPi-IIa in the PT cells. This effect is mediated via a mechanism involving coactivation of both ERα and ERβ, which likely form a functional heterodimer complex in the rat kidney proximal tubule. Copyright © 2015 the American Physiological Society.

Estrogen directly and specifically downregulates NaPi-IIa through the activation of both estrogen receptor isoforms (ERα and ERβ) in rat kidney proximal tubule

PubMed Central

Burris, Dara; Webster, Rose; Sheriff, Sulaiman; Faroqui, Rashma; Levi, Moshe; Hawse, John R.

2015-01-01

We have previously demonstrated that estrogen (E2) downregulates phosphate transporter NaPi-IIa and causes phosphaturia and hypophosphatemia in ovariectomized rats. In the present study, we examined whether E2 directly targets NaPi-IIa in the proximal tubule (PT) and studied the respective roles of estrogen receptor isoforms (ERα and ERβ) in the downregulation of NaPi-IIa using both in vivo and an in vitro expression systems. We found that estrogen specifically downregulates NaPi-IIa but not NaPi-IIc or Pit2 in the kidney cortex. Proximal tubules incubated in a “shake” suspension with E2 for 24 h exhibited a dose-dependent decrease in NaPi-IIa protein abundance. Results from OVX rats treated with specific agonists for either ERα [4,4′,4″;-(4-propyl-[1H]-pyrazole-1,3,5-triyl) trisphenol, PPT] or ERβ [4,4′,4″-(4-propyl-[1H]-pyrazole-1,3,5-triyl) trisphenol, DPN] or both (PPT + DPN), indicated that only the latter caused a sharp downregulation of NaPi-IIa, along with significant phosphaturia and hypophosphatemia. Lastly, heterologous expression studies demonstrated that estrogen downregulated NaPi-IIa only in U20S cells expressing both ERα and ERβ, but not in cells expressing either receptor alone. In conclusion, these studies demonstrate that rat PT cells express both ERα and ERβ and that E2 induces phosphaturia by directly and specifically targeting NaPi-IIa in the PT cells. This effect is mediated via a mechanism involving coactivation of both ERα and ERβ, which likely form a functional heterodimer complex in the rat kidney proximal tubule. PMID:25608964

Role of natriuretic peptide receptor 2-mediated signaling in meiotic arrest of zebrafish oocytes and its estrogen regulation through G protein-coupled estrogen receptor (Gper).

PubMed

Pang, Yefei; Thomas, Peter

2018-03-22

Natriuretic peptide type C (NPPC) and its receptor, natriuretic peptide receptor 2 (NPR2), have essential roles in maintaining meiotic arrest of oocytes in several mammalian species. However, it is not known if a similar mechanism exists in non-mammalian vertebrates. Using zebrafish as a model, we show that Nppc is expressed in ovarian follicle cells, whereas Npr2 is mainly detected in oocytes. Treatment of intact and defolliculated oocytes with 100 nM NPPC for 6 h caused a large increase in cGMP concentrations, and a significant decrease in oocyte maturation (OM), an effect that was mimicked by treatment with 8-Br-cGMP. Treatment with E2 and G-1, the specific GPER agonist, also increased cGMP levels. Cyclic AMP levels were also increased by treatments with 8-Br-cGMP, E2 and G1. The estrogen upregulation of cAMP levels was blocked by co-treatment with AG1478, an inhibitor of EGFR activation. Gene expression of npr2, but not nppc, was significantly upregulated in intact oocytes by 6 h treatments with 20 nM E2 and G-1. Both cilostamide, a phosphodiesterase 3 (PDE3) inhibitor, and rolipram, a PDE4 inhibitor, significantly decreased OM of intact and defolliculated oocytes, and enhanced the inhibitory effects of E2 and G-1 on OM. These findings indicate the presence of a Nppc/Npr2/cGMP pathway maintaining meiotic arrest in zebrafish oocytes that is upregulated by estrogen activation of Gper. Collectively, the results suggest that Nppc through Npr2 cooperates with E2 through Gper in upregulation of cGMP levels to inhibit phosphodiesterase activity resulting in maintenance of oocyte meiotic arrest in zebrafish. Copyright © 2018 Elsevier Inc. All rights reserved.

Regulation of expression of hyperalgesic priming by estrogen receptor alpha in the rat

PubMed Central

Ferrari, Luiz F.; Araldi, Dionéia; Levine, Jon D.

2017-01-01

Hyperalgesic priming, a sexually dimorphic model of transition to chronic pain, is expressed as prolongation of prostaglandin E2 (PGE2)-induced hyperalgesia by the activation of an additional pathway including an autocrine mechanism at the plasma membrane. The autocrine mechanism involves the transport of cAMP to the extracellular space, and its conversion to AMP and adenosine, by ecto-5′phosphodiesterase and ecto-5′nucleotidase, respectively. The end product, adenosine, activates A1 receptors, producing delayed onset prolongation of PGE2 hyperalgesia. We tested the hypothesis that the previously reported, estrogen-dependent, sexual dimorphism observed in the induction of priming is present in the mechanisms involved in its expression, as a regulatory effect on ecto-5′nucleotidase by estrogen receptor alpha (EsRα), in female rats. In the primed paw AMP hyperalgesia was dependent on conversion to adenosine, being prevented by ecto-5′nucleotidase inhibitor AMPCP and A1 receptor antagonist DPCPX. To investigate an interaction between EsRα and ecto-5′nucleotidase, we treated primed female rats with ODN antisense or mismatch against EsRα mRNA. While in rats treated with antisense AMP-induced hyperalgesia was abolished, the A1 receptor agonist N6-cyclopentiladenosine (CPA) still produced hyperalgesia. Thus, EsRα interacts with this autocrine pathway at the level of ecto-5′nucleotidase. These results demonstrate a sexually dimorphic mechanism for the expression of priming. Perspective This study presents evidence of an estrogen-dependent mechanism of expression of chronic pain in females, supporting the suggestion that differential targets must be considered when establishing protocols for the treatment of painful conditions in males and females. PMID:28089711

The antiestrogen ICI 182,780 decreases the expression of estrogen receptor-alpha but has no effect on estrogen receptor-beta and androgen receptor in rat efferent ductules

PubMed Central

Oliveira, Cleida A; Nie, Rong; Carnes, Kay; Franca, Luiz R; Prins, Gail S; Saunders, Philippa TK; Hess, Rex A

2003-01-01

Background The antiestrogen ICI 182,780 has been used successfully as an alternative experimental model for the study of estrogen action in the rodent adult male reproductive tract. Although ICI 182,780 causes severe alterations in testicular and efferent ductule morphology and function, the effects on the expression of estrogen and androgen receptors in the male have not been shown. Methods In the present study, adult male rats were treated with ICI 182,780 for 7 to 150 days, to evaluate the time-response effects of the treatment on the pattern of ERα, ERβ and AR protein expression in the efferent ductules. The receptors were localized using immunohistochemistry. Results ERα, ERβ and AR have distinct cellular distribution in the testis and efferent ductules. Staining for ERα is nearly opposite of that for ERβ, as ERα shows an increase in staining intensity from proximal to distal efferent ductules, whereas ERβ shows the reverse. Androgen receptor follows that of ERα. ICI 182,780 caused a gradual but dramatic decrease in ERα expression in the testis and efferent ductules, but no change in ERβ and AR expression. Conclusions The differential response of ERα and ERβ proteins to ICI 182,780 indicates that these receptors are regulated by different mechanisms in the male reproductive tract. PMID:14613549

Estrogen-related receptor {alpha} is essential for the expression of antioxidant protection genes and mitochondrial function

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rangwala, Shamina M.; Li, Xiaoyan; Lindsley, Loren

2007-05-25

Estrogen-related receptor {alpha} (ERR{alpha}) is an important mediator of mitochondrial biogenesis and function. To investigate the transcriptional network controlling these phenomena, we investigated mitochondrial gene expression in embryonic fibroblasts isolated from ERR{alpha} null mice. Peroxisome proliferator-activated receptor {gamma} coactivator-1{alpha} (PGC-1{alpha}) stimulated mitochondrial gene expression program in control cells, but not in the ERR{alpha} null cells. Interestingly, the induction of levels of mitochondrial oxidative stress protection genes in response to increased PGC-1{alpha} levels was dependent on ERR{alpha}. Furthermore, we found that the PGC-1{alpha}-mediated induction of estrogen-related receptor {gamma} and nuclear respiratory factor 2 (NRF-2), was dependent on the presence of ERR{alpha}.more » Basal levels of NRF-2 were decreased in the absence of ERR{alpha}. The absence of ERR{alpha} resulted in a decrease in citrate synthase enzyme activity in response to PGC-1{alpha} overexpression. Our results indicate an essential role for ERR{alpha} as a key regulator of oxidative metabolism.« less

Activation of Estrogen Receptor Transfected into a Receptor-Negative Brest Cancer Cell Line Decreases the Metastatic and Invasive Potential of the Cells

NASA Astrophysics Data System (ADS)

Garcia, Marcel; Derocq, Danielle; Freiss, Gilles; Rochefort, Henri

1992-12-01

Breast cancers containing estrogen receptors are responsive to antiestrogen treatment and have a better prognosis than estrogen receptor-negative tumors. The loss of estrogen and progesterone receptors appears to be associated with a progression to less-differentiated tumors. We transfected the human estrogen receptor into the estrogen receptor-negative metastatic breast cancer cell line MDA-MB-231 in an attempt to restore their sensitivity to antiestrogens. Two stable sublines of MDA-MB-231 cells (HC1 and HE5) expressing functional estrogen receptors were studied for their ability to grow and invade in vitro and to metastasize in athymic nude mice. The number and size of lung metastases developed by these two sublines in ovariectomized nude mice was not markedly altered by tamoxifen but was inhibited 3-fold by estradiol. Estradiol also significantly inhibited in vitro cell proliferation of these sublines and their invasiveness in Matrigel, a reconstituted basement membrane, whereas the antiestrogens 4-hydroxytamoxifen and ICI 164,384 reversed these effects. These results show that estradiol inhibits the metastatic ability of estrogen receptornegative breast cancer cells following transfection with the estrogen receptor, whereas estrogen receptor-positive breast cancers are stimulated by estrogen, indicating that factors other than the estrogen receptor are involved in progression toward hormone independence. Reactivation or transfer of the estrogen receptor gene can therefore be considered as therapeutic approaches to hormone-independent cancers

The putative G-protein coupled estrogen receptor agonist G-1 suppresses proliferation of ovarian and breast cancer cells in a GPER-independent manner

PubMed Central

Wang, Cheng; Lv, Xiangmin; Jiang, Chao; Davis, John S

2012-01-01

G-protein coupled estrogen receptor 1 (GPER) plays an important role in mediating estrogen action in many different tissues under both physiological and pathological conditions. G-1 (1-[4-(6-bromobenzo[1,3]dioxol-5yl)-3a,4,5,9b-tetrahydro-3H-cyclopenta [c]quinolin-8-yl]-ethanone) has been developed as a selective GPER agonist to distinguish estrogen actions mediated by GPER from those mediated by classic estrogen receptors. In the present study, we surprisingly found that G-1 suppressed proliferation and induced apoptosis of KGN cells (a human ovarian granulosa cell tumor cell line), actions that were not blocked by a selective GPER antagonist G15 or siRNA knockdown of GPER. G-1 also suppressed proliferation and induced cell apoptosis in GPER-negative HEK-293 cells and MDA-MB 231 breast cancer cells. Our results demonstrate that G-1 suppresses proliferation of ovarian and breast cancer cells in a GPER-independent manner. G-1 may be a candidate for the development of drugs against ovarian and breast cancer. PMID:23145207

Treatment of BG-1 Ovarian Cancer Cells Expressing Estrogen Receptors with Lambda-cyhalothrin and Cypermethrin Caused a Partial Estrogenicity Via an Estrogen Receptor-dependent Pathway

PubMed Central

Kim, Cho-Won; Go, Ryeo-Eun

2015-01-01

Synthetic pyrethroids (SPs) are the most common pesticides which are recently used for indoor pest control. The widespread use of SPs has resulted in the increased exposure to wild animals and humans. Recently, some SPs are suspected as endocrine disrupting chemicals (EDCs) and have been assessed for their potential estrogenicity by adopting various analyzing assays. In this study, we examined the estrogenic effects of lambda-cyhalothrin (LC) and cypermethrin (CP), the most commonly used pesticides in Korea, using BG-1 ovarian cancer cells expressing estrogen receptors (ERs). To evaluate the estrogenic activities of two SPs, LC and CP, we employed MTT assay and reverse-transcription polymerase chain reaction (RT-PCR) in LC or CP treated BG-1 ovarian cancer cells. In MTT assay, LC (10−6 M) and CP (10−5 M) significantly induced the growth of BG-1 cancer cells. LC or CP-induced cell growth was antagonized by addition of ICI 182,720 (10−8 M), an ER antagonist, suggesting that this effect appears to be mediated by an ER-dependent manner. Moreover, RT-PCR results showed that transcriptional level of cyclin D1, a cell cycle-regulating gene, was significantly up-regulated by LC and CP, while these effects were reversed by co-treatment of ICI 182,780. However, p21, a cyclin D-ckd-4 inhibitor gene, was not altered by LC or CP. Moreover, ERα expression was not significantly changed by LC and CP, while downregulated by E2. Finally, in xenografted mouse model transplanted with human BG-1 ovarian cancer cells, E2 significantly increased the tumor volume compare to a negative control, but LC did not. Taken together, these results suggest that LC and CP may possess estrogenic potentials by stimulating the growth of BG-1 ovarian cancer cells via partially ER signaling pathway associated with cell cycle as did E2, but this estrogenic effect was not found in in vivo mouse model. PMID:26877835

Not lost in translation: Emerging clinical importance of the G protein-coupled estrogen receptor GPER.

PubMed

Barton, Matthias

2016-07-01

It has been 20years that the G protein-coupled estrogen receptor (GPER) was cloned as the orphan receptor GPR30 from multiple cellular sources, including vascular endothelial cells. Here, I will provide an overview of estrogen biology and the historical background leading to the discovery of rapid vascular estrogen signaling. I will also review the recent advances in the understanding of the mechanisms underlying GPER function, its role in physiology and disease, some of the currently available GPER-targeting drugs approved for clinical use such as SERMs (selective estrogen receptor modulators) and SERDs (selective estrogen receptor downregulators). Many of currently used drugs such as tamoxifen, raloxifene, or faslodex™/fulvestrant were discovered targeting GPER many years after they had been introduced to the clinics for entirely different purposes. This has important implications for the clinical use of these drugs and their modes of action, which I have termed 'reverse translational medicine'. In addition, environmental pollutants known as 'endocrine disruptors' have been found to bind to GPER. This article also discusses recent evidence in these areas as well as opportunities in translational clinical medicine and GPER research, including medical genetics, personalized medicine, prevention, and its theranostic use. Copyright © 2016 Elsevier Inc. All rights reserved.

Estrogen receptors involvement in intervertebral discogenic pain of the elderly women: colocalization and correlation with the expression of Substance P in nucleus pulposus

PubMed Central

Li, Xin-Feng; Yu, Bu-Wei

2017-01-01

Estrogenic modulation of pain is an exceedingly complex phenomenon. However, whether estrogen is involved in discogenic low back pain still remains unclear. Here, immunoreactivity staining technique was used to examine the expression level of the estrogen receptors (ERα and ERβ) and a pain related neuropeptide, Substance P in the lumbar intervertebral discs to analyze the relationship between the ERs and Substance P. Nucleus pulposus tissues of 23 elderly female patients were harvested during spinal surgeries and made to detect the immunoreactivity staining of ERα, ERβ and Substance P. The colocalization and intensities of ERs and Substance P were explored and evaluated respectively. The correlations between changes of ERα, ERβ and Substance P were also assessed.Our results revealed that Substance P colocalized with ERα and ERβ both in cytoplasm and nucleus of the nucleus pulposus cells. HSCORE analysis indicated that Substance P negatively correlated with both ERα and ERβ expression. Collectively, the crosstalk between ERs and Substance P might exist in the disc tissue. Estrogen-dependent pain mechanism might partly be mediated through ERs and Substance P in the nucleus pulposus of the elderly females. Estrogen and its receptors might be drug targets in discogenic low back pain diseases. PMID:28430617

A-C Estrogens as Potent and Selective Estrogen Receptor-Beta Agonists (SERBAs) to Enhance Memory Consolidation under Low-Estrogen Conditions.

PubMed

Hanson, Alicia M; Perera, K L Iresha Sampathi; Kim, Jaekyoon; Pandey, Rajesh K; Sweeney, Noreena; Lu, Xingyun; Imhoff, Andrea; Mackinnon, Alexander Craig; Wargolet, Adam J; Van Hart, Rochelle M; Frick, Karyn M; Donaldson, William A; Sem, Daniel S

2018-06-14

Estrogen receptor-beta (ERβ) is a drug target for memory consolidation in postmenopausal women. Herein is reported a series of potent and selective ERβ agonists (SERBAs) with in vivo efficacy that are A-C estrogens, lacking the B and D estrogen rings. The most potent and selective A-C estrogen is selective for activating ER relative to seven other nuclear hormone receptors, with a surprising 750-fold selectivity for the β over α isoform and with EC 50 s of 20-30 nM in cell-based and direct binding assays. Comparison of potency in different assays suggests that the ER isoform selectivity is related to the compound's ability to drive the productive conformational change needed to activate transcription. The compound also shows in vivo efficacy after microinfusion into the dorsal hippocampus and after intraperitoneal injection (0.5 mg/kg) or oral gavage (0.5 mg/kg). This simple yet novel A-C estrogen is selective, brain penetrant, and facilitates memory consolidation.

Bone Marrow Oxytocin Mediates the Anabolic Action of Estrogen on the Skeleton*

PubMed Central

Colaianni, Graziana; Sun, Li; Di Benedetto, Adriana; Tamma, Roberto; Zhu, Ling-Ling; Cao, Jay; Grano, Maria; Yuen, Tony; Colucci, Sylvia; Cuscito, Concetta; Mancini, Lucia; Li, Jianhua; Nishimori, Katsuhiko; Bab, Itai; Lee, Heon-Jin; Iqbal, Jameel; Young, W. Scott; Rosen, Clifford; Zallone, Alberta; Zaidi, Mone

2012-01-01

Estrogen uses two mechanisms to exert its effect on the skeleton: it inhibits bone resorption by osteoclasts and, at higher doses, can stimulate bone formation. Although the antiresorptive action of estrogen arises from the inhibition of the MAPK JNK, the mechanism of its effect on the osteoblast remains unclear. Here, we report that the anabolic action of estrogen in mice occurs, at least in part, through oxytocin (OT) produced by osteoblasts in bone marrow. We show that the absence of OT receptors (OTRs) in OTR−/− osteoblasts or attenuation of OTR expression in silenced cells inhibits estrogen-induced osteoblast differentiation, transcription factor up-regulation, and/or OT production in vitro. In vivo, OTR−/− mice, known to have a bone formation defect, fail to display increases in trabecular bone volume, cortical thickness, and bone formation in response to estrogen. Furthermore, osteoblast-specific Col2.3-Cre+/OTRfl/fl mice, but not TRAP-Cre+/OTRfl/fl mice, mimic the OTR−/− phenotype and also fail to respond to estrogen. These data attribute the phenotype of OTR deficiency to an osteoblastic rather than an osteoclastic defect. Physiologically, feed-forward OT release in bone marrow by a rising estrogen concentration may facilitate rapid skeletal recovery during the latter phases of lactation. PMID:22761429

Estrogen Receptor-α Correlates with Higher Fungal Cell Number in Oral Paracoccidioidomycosis in Women.

PubMed

Caixeta, Clenivaldo Alves; de Carli, Marina Lara; Ribeiro Júnior, Noé Vital; Sperandio, Felipe Fornias; Nonogaki, Suely; Nogueira, Denismar Alves; Pereira, Alessandro Antônio Costa; Hanemann, João Adolfo Costa

2018-05-23

Paracoccidioidomycosis is a neglected tropical fungal infection with great predilection for adult men, indicating the participation of female hormone estrogen in preventing paracoccidioidomycosis development in women. Estrogen has an immunologic effect leading to polarization toward the Th2 immune response, which favors the disease evolution. To evaluate estrogen and progesterone receptors in oral paracoccidioidomycosis lesions and to verify any association with tissue fungi counting in women and men. Thirty-two cases of chronic oral paracoccidioidomycosis were included. Immunohistochemical analyses for anti-estrogen receptor-α, anti-progesterone receptor and anti-Paracoccidioides brasiliensis antibodies were performed. The differences between women and men and the relations among the immunomarkers for each gender were also evaluated. A significant positive correlation was observed between estrogen receptor-α and the amount of fungi in women. In addition, estrogen receptor-α was mildly expressed in the inflammatory cells of female patients, while progesterone receptor was expressed in both genders, with similar expression between women and men. Moreover, fungi counting revealed no differences between genders. Estrogen receptor-α was expressed only in women and showed a positive correlation with the amount of fungi in oral paracoccidioidomycosis, while progesterone receptor was observed in both genders and exhibited no correlation with estrogen receptor-α or fungi counting.

Binding of alkylphenols and alkylated non-phenolics to rainbow trout (Oncorhynchus mykiss) hepatic estrogen receptors.

PubMed

Tollefsen, Knut-Erik; Julie Nilsen, Anja

2008-02-01

Alkylphenols are well-known endocrine disrupters, mediating effects through the estrogen receptor (ER). In the present work, the interaction of alkylphenols and alkylated non-phenolics with hepatic rainbow trout (Oncorhynchus mykiss) estrogen receptors (rtERs) was determined. The role of alkyl chain length and branching, substituent position, number of alkylated groups, and the requirement of a phenolic ring structure was assessed. The results showed that the rtERs bound most alkylphenols, although with 20,000 to 2 million times lower affinity than the endogenous estrogen 17beta-estradiol. Mono-substituted alkylphenols with moderate (C4-C6) and long (C8 and C12) alkyl chain length in the para position exhibited the highest affinity for the rtERs. Substitution with multiple alkyl groups, presence of substituents in the ortho- and meta-position, and lack of a hydroxyl group on the benzene ring reduced the binding affinity. The rtERs resembled the reported binding specificity of the human ER for alkylphenols, although some exceptions were identified.

ROLE OF ESTROGEN RECEPTOR-α ON FOOD DEMAND ELASTICITY

PubMed Central

Minervini, Vanessa; Rowland, Neil E.; Robertson, Kimberly L.; Foster, Thomas C.

2016-01-01

Estrogens have been shown to have an inhibitory effect on food intake under free-feeding conditions, yet the effects of estrogens on food-maintained operant responding have been studied to a much lesser extent and, thus, are not well understood. Therefore, the purpose of the present experiment was to use a behavioral economics paradigm to assess differences in demand elasticity between mice with knockout of the estrogen receptor subtype α, knockout of subtype β, and their wild type controls. The mice responded in a closed economy, and the price of food was increased by increasing the fixed-ratio response requirement every four sessions. Overall, we found that mice with the knockout of receptor subtype α had the most elastic demand functions. Therefore, under these conditions, estrogens increased food seeking via activation of the receptor subtype α. The results were inconsistent with those reported by previous studies that employed free-feeding conditions. PMID:25869426

Role of estrogen receptor-α on food demand elasticity.

PubMed

Minervini, Vanessa; Rowland, Neil E; Robertson, Kimberly L; Foster, Thomas C

2015-05-01

Estrogens have been shown to have an inhibitory effect on food intake under free-feeding conditions, yet the effects of estrogens on food-maintained operant responding have been studied to a much lesser extent and, thus, are not well understood. Therefore, the purpose of the present experiment was to use a behavioral economics paradigm to assess differences in demand elasticity between mice with knockout of the estrogen receptor subtype α, knockout of subtype β, and their wild type controls. The mice responded in a closed economy, and the price of food was increased by increasing the fixed-ratio response requirement every four sessions. Overall, we found that mice with the knockout of receptor subtype α had the most elastic demand functions. Therefore, under these conditions, estrogens increased food seeking via activation of the receptor subtype α. The results were inconsistent with those reported by previous studies that employed free-feeding conditions. © Society for the Experimental Analysis of Behavior.

Combinations of physiologic estrogens with xenoestrogens alter calcium and kinase responses, prolactin release, and membrane estrogen receptor trafficking in rat pituitary cells

PubMed Central

2010-01-01

Background Xenoestrogens such as alkylphenols and the structurally related plastic byproduct bisphenol A have recently been shown to act potently via nongenomic signaling pathways and the membrane version of estrogen receptor-α. Though the responses to these compounds are typically measured individually, they usually contaminate organisms that already have endogenous estrogens present. Therefore, we used quantitative medium-throughput screening assays to measure the effects of physiologic estrogens in combination with these xenoestrogens. Methods We studied the effects of low concentrations of endogenous estrogens (estradiol, estriol, and estrone) at 10 pM (representing pre-development levels), and 1 nM (representing higher cycle-dependent and pregnancy levels) in combinations with the same levels of xenoestrogens in GH3/B6/F10 pituitary cells. These levels of xenoestrogens represent extremely low contamination levels. We monitored calcium entry into cells using Fura-2 fluorescence imaging of single cells. Prolactin release was measured by radio-immunoassay. Extracellular-regulated kinase (1 and 2) phospho-activations and the levels of three estrogen receptors in the cell membrane (ERα, ERβ, and GPER) were measured using a quantitative plate immunoassay of fixed cells either permeabilized or nonpermeabilized (respectively). Results All xenoestrogens caused responses at these concentrations, and had disruptive effects on the actions of physiologic estrogens. Xenoestrogens reduced the % of cells that responded to estradiol via calcium channel opening. They also inhibited the activation (phosphorylation) of extracellular-regulated kinases at some concentrations. They either inhibited or enhanced rapid prolactin release, depending upon concentration. These latter two dose-responses were nonmonotonic, a characteristic of nongenomic estrogenic responses. Conclusions Responses mediated by endogenous estrogens representing different life stages are vulnerable to very

G-protein coupled estrogen receptor (GPER) inhibits final oocyte maturation in common carp, Cyprinus carpio.

PubMed

Majumder, Suravi; Das, Sumana; Moulik, Sujata Roy; Mallick, Buddhadev; Pal, Puja; Mukherjee, Dilip

2015-01-15

GPR-30, now named as GPER (G protein-coupled estrogen receptor) was first identified as an orphan receptor and subsequently shown to be required for estrogen-mediated signaling in certain cancer cells. Later studies demonstrated that GPER has the characteristics of a high affinity estrogen membrane receptor on Atlantic croaker and zebra fish oocytes and mediates estrogen inhibition of oocyte maturation in these two distantly related teleost. To determine the broad application of these findings to other teleost, expression of GPER mRNA and its involvement in 17β-estradiol mediated inhibition of oocyte maturation in other cyprinid, Cyprinus carpio was investigated. Carp oocytes at pre-vitellogenic, late-vitellogenic and post-vitellogenic stages of development contained GPER mRNA and its transcribed protein with a maximum at late-vitellogenic oocytes. Ovarian follicular cells did not express GPER mRNA. Carp oocytes GPER mRNA was essentially identical to that found in other perciformes and cyprinid fish oocytes. Both spontaneous and 17,20β-dihydroxy-4-pregnen-3-one (17,20β-P)-induced oocyte maturation in carp was significantly decreased when they were incubated with either E2, or GPER agonist G-1. On the other hand spontaneous oocyte maturation was significantly increased when carp ovarian follicles were incubated with an aromatase inhibitor, fadrozole, GPER antagonist, G-15 and enzymatic removal of the ovarian follicle cell layers. This increase in oocyte maturation was partially reversed by co-treatment with E2. Consistent with previous findings with human and fish GPR30, E2 treatment in carp oocytes caused increase in cAMP production and simultaneously decrease in oocyte maturation, which was inhibited by the addition of 17,20β-P. The results suggest that E2 and GPER play a critical role in regulating re-entry in to meiotic cell cycle in carp oocytes. Copyright © 2014 Elsevier Inc. All rights reserved.

T Lymphocytes Do Not Directly Mediate the Protective Effect of Estrogen on Experimental Autoimmune Encephalomyelitis

PubMed Central

Polanczyk, Magdalena J.; Jones, Richard E.; Subramanian, Sandhya; Afentoulis, Michael; Rich, Cathleen; Zakroczymski, Melissa; Cooke, Paul; Vandenbark, Arthur A.; Offner, Halina

2004-01-01

Gender influences mediated by 17β-estradiol (E2) have been associated with susceptibility to and severity of autoimmune diseases such as diabetes, arthritis, and multiple sclerosis. In this regard, we have shown that estrogen receptor-α (Esr1) is crucial for the protective effect of 17β-estradiol (E2) in murine experimental autoimmune encephalitis (EAE), an animal model of multiple sclerosis. The expression of estrogen receptors among various immune cells (eg, T and B lymphocytes, antigen-presenting cells) suggests that the therapeutic effect of E2 is likely mediated directly through specific receptor binding. However, the target immune cell populations responsive to E2 treatment have not been identified. In the current study, we induced EAE in T-cell-deficient, severe combined immunodeficient mice or in immunocompetent mice with encephalitogenic T cells from wild-type Esr1+/+ or Esr1 knockout (Esr1−/−) donors and compared the protective E2 responses. The results showed that E2-responsive, Esr1+/+ disease-inducing encephalitogenic T cells were neither necessary nor sufficient for E2-mediated protection from EAE. Instead, the therapeutic response appeared to be mediated through direct effects on nonlymphocytic, E2-responsive cells and down-regulation of the inflammatory response in the central nervous system. These results provide the first demonstration that the protective effect of E2 on EAE is not mediated directly through E2-responsive T cells and raise the alternative possibility that nonlymphocytic cells such as macrophages, dendritic cells, or other nonlymphocytic cells are primarily responsive to E2 treatment in EAE. PMID:15579449

Bisphenol-A rapidly promotes dynamic changes in hippocampal dendritic morphology through estrogen receptor-mediated pathway by concomitant phosphorylation of NMDA receptor subunit NR2B

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xu Xiaohong, E-mail: xuxh63@zjnu.cn; Ye Yinping; Li Tao

Bisphenol-A (BPA) is known to be a potent endocrine disrupter. Evidence is emerging that estrogen exerts a rapid influence on hippocampal synaptic plasticity and the dendritic spine density, which requires activation of NMDA receptors. In the present study, we investigated the effects of BPA (ranging from 1 to 1000 nM), focusing on the rapid dynamic changes in dendritic filopodia and the expressions of estrogen receptor (ER) {beta} and NMDA receptor, as well as the phosphorylation of NMDA receptor subunit NR2B in the cultured hippocampal neurons. A specific ER antagonist ICI 182,780 was used to examine the potential involvement of ERs.more » The results demonstrated that exposure to BPA (ranging from 10 to 1000 nM) for 30 min rapidly enhanced the motility and the density of dendritic filopodia in the cultured hippocampal neurons, as well as the phosphorylation of NR2B (pNR2B), though the expressions of NMDA receptor subunits NR1, NR2B, and ER{beta} were not changed. The antagonist of ERs completely inhibited the BPA-induced increases in the filopodial motility and the number of filopodia extending from dendrites. The increased pNR2B induced by BPA (100 nM) was also completely eliminated. Furthermore, BPA attenuated the effects of 17{beta}-estradiol (17{beta}-E{sub 2}) on the dendritic filopodia outgrowth and the expression of pNR2B when BPA was co-treated with 17{beta}-E{sub 2}. The present results suggest that BPA, like 17{beta}-E{sub 2}, rapidly results in the enhanced motility and density of dendritic filopodia in the cultured hippocampal neurons with the concomitant activation of NMDA receptor subunit NR2B via an ER-mediated signaling pathway. Meanwhile, BPA suppressed the enhancement effects of 17{beta}-E{sub 2} when it coexists with 17{beta}-E{sub 2}. These results provided important evidence suggesting the neurotoxicity of the low levels of BPA during the early postnatal development of the brain.« less

The human oxytocin gene promoter is regulated by estrogens.

PubMed

Richard, S; Zingg, H H

1990-04-15

Gonadal steroids affect brain function primarily by altering the expression of specific genes, yet the specific mechanisms by which neuronal target genes undergo such regulation are unknown. Recent evidence suggests that the expression of the neuropeptide gene for oxytocin (OT) is modulated by estrogens. We therefore examined the possibility that this regulation occurred via a direct interaction of the estrogen-receptor complex with cis-acting elements flanking the OT gene. DNA-mediated gene transfer experiments were performed using Neuro-2a neuroblastoma cells and chimeric plasmids containing portions of the human OT gene 5'-glanking region linked to the chloramphenicol acetyltransferase gene. We identified a 19-base pair region located at -164 to -146 upstream of the transcription start site which is capable of conferring estrogen responsiveness to the homologous as well as to a heterologous promoter. The hormonal response is strictly dependent on the presence of intracellular estrogen receptors, since estrogen induced stimulation occurred only in Neuro-2a cells co-transfected with an expression vector for the human estrogen receptor. The identified region contains a novel imperfect palindrome (GGTGACCTTGACC) with sequence similarity to other estrogen response elements (EREs). To define cis-acting elements that function in synergism with the ERE, sequences 3' to the ERE were deleted, including the CCAAT box, two additional motifs corresponding to the right half of the ERE palindrome (TGACC), as well as a CTGCTAA heptamer similar to the "elegans box" found in Caenorhabditis elegans. Interestingly, optimal function of the identified ERE was fully independent of these elements and only required a short promoter region (-49 to +36). Our studies define a molecular mechanism by which estrogens can directly modulate OT gene expression. However, only a subset of OT neurons are capable of binding estrogens, therefore, direct action of estrogens on the OT gene may be

The choroid plexus harbors a circadian oscillator modulated by estrogens.

PubMed

Quintela, Telma; Albuquerque, Tânia; Lundkvist, Gabriella; Carmine Belin, Andrea; Talhada, Daniela; Gonçalves, Isabel; Carro, Eva; Santos, Cecília R A

2018-02-01

The suprachiasmatic nucleus (SCN) of the hypothalamus is considered the master circadian oscillator in mammals. However, extra-SCN structures in the brain also display daily rhythms. Recently, we have demonstrated that the choroid plexus (CP) expresses core clock genes that are subjected to circadian regulation in a sex-dependent manner. By using CP explants cultured from female knock-in mice carrying the Period-luciferase transgene, we show that CP exhibits endogenous circadian rhythms of PERIOD2::LUCIFERASE expression. Furthermore, we demonstrate that estrogen declines following ovariectomy modulates the daily rhythm expression of Bmal1, Per1 and Per2 in female rat CP, corroborating data obtained in experiments where rat CP epithelial cell (CPEC) cultures were incubated with 17β-estradiol (E2). The molecular mechanism underlying these effects was also investigated, and we provide evidence that the estrogen receptor (ER) mediates the response of clock genes to E2. In conclusion, our study proves that the CP harbors a circadian oscillator that is modulated by estrogens and demonstrates that E2 regulation occurs through an estrogen-receptor-dependent mechanism.

Trichostatin A enhances estrogen receptor-alpha repression in MCF-7 breast cancer cells under hypoxia

DOE Office of Scientific and Technical Information (OSTI.GOV)

Noh, Hyunggyun; Park, Joonwoo; Shim, Myeongguk

Estrogen receptor (ER) is a crucial determinant of resistance to endocrine therapy, which may change during the progression of breast cancer. We previously showed that hypoxia induces ESR1 gene repression and ERα protein degradation via proteasome-mediated pathway in breast cancer cells. HDAC plays important roles in the regulation of histone and non-histone protein post-translational modification. HDAC inhibitors can induce epigenetic changes and have therapeutic potential for targeting various cancers. Trichostatin A exerts potent antitumor activities against breast cancer cells in vitro and in vivo. In this report, we show that TSA augments ESR1 gene repression at the transcriptional level and downregulates ERαmore » protein expression under hypoxic conditions through a proteasome-mediated pathway. TSA-induced estrogen response element-driven reporter activity in the absence of estrogen was synergistically enhanced under hypoxia; however, TSA inhibited cell proliferation under both normoxia and hypoxia. Our data show that the hypoxia-induced repression of ESR1 and degradation of ERα are enhanced by concomitant treatment with TSA. These findings expand our understanding of hormone responsiveness in the tumor microenvironment; however, additional in-depth studies are required to elucidate the detailed mechanisms of TSA-induced ERα regulation under hypoxia. - Highlights: • TSA augments ESR1 gene repression at the transcriptional level under hypoxia. • TSA downregulates ERα protein expression under hypoxia. • TSA-induced ERα regulation under hypoxia is essential for understanding the behavior and progression of breast cancer.« less

Computational estimation of rainbow trout estrogen receptor binding affinities for environmental estrogens

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shyu, Conrad; Cavileer, Timothy D.; Nagler, James J.

2011-02-01

Environmental estrogens have been the subject of intense research due to their documented detrimental effects on the health of fish and wildlife and their potential to negatively impact humans. A complete understanding of how these compounds affect health is complicated because environmental estrogens are a structurally heterogeneous group of compounds. In this work, computational molecular dynamics simulations were utilized to predict the binding affinity of different compounds using rainbow trout (Oncorhynchus mykiss) estrogen receptors (ERs) as a model. Specifically, this study presents a comparison of the binding affinity of the natural ligand estradiol-17{beta} to the four rainbow trout ER isoformsmore » with that of three known environmental estrogens 17{alpha}-ethinylestradiol, bisphenol A, and raloxifene. Two additional compounds, atrazine and testosterone, that are known to be very weak or non-binders to ERs were tested. The binding affinity of these compounds to the human ER{alpha} subtype is also included for comparison. The results of this study suggest that, when compared to estradiol-17{beta}, bisphenol A binds less strongly to all four receptors, 17{alpha}-ethinylestradiol binds more strongly, and raloxifene has a high affinity for the {alpha} subtype only. The results also show that atrazine and testosterone are weak or non-binders to the ERs. All of the results are in excellent qualitative agreement with the known in vivo estrogenicity of these compounds in the rainbow trout and other fishes. Computational estimation of binding affinities could be a valuable tool for predicting the impact of environmental estrogens in fish and other animals.« less

Rapid effects of estrogens on behavior: environmental modulation and molecular mechanisms.

PubMed

Laredo, Sarah A; Villalon Landeros, Rosalina; Trainor, Brian C

2014-10-01

Estradiol can modulate neural activity and behavior via both genomic and nongenomic mechanisms. Environmental cues have a major impact on the relative importance of these signaling pathways with significant consequences for behavior. First we consider how photoperiod modulates nongenomic estrogen signaling on behavior. Intriguingly, short days permit rapid effects of estrogens on aggression in both rodents and song sparrows. This highlights the importance of considering photoperiod as a variable in laboratory research. Next we review evidence for rapid effects of estradiol on ecologically-relevant behaviors including aggression, copulation, communication, and learning. We also address the impact of endocrine disruptors on estrogen signaling, such as those found in corncob bedding used in rodent research. Finally, we examine the biochemical mechanisms that may mediate rapid estrogen action on behavior in males and females. A common theme across these topics is that the effects of estrogens on social behaviors vary across different environmental conditions. Copyright © 2014 Elsevier Inc. All rights reserved.

Differential neonatal imprinting and regulation by estrogen of estrogen receptor subtypes alpha and beta and of the truncated estrogen receptor product (TERP-1) mRNA expression in the male rat pituitary.

PubMed

Tena-Sempere, M; Barreiro, M L; González, L C; Pinilla, L; Aguilar, E

2001-11-01

Two distinct nuclear estrogen receptors (ERs) have been identified, the classical one, renamed ERalpha, and the more recently cloned ERbeta. In a variety of tissues, gene expression of both receptor subtypes results in the generation of multiple transcripts encoding the full-length as well as several alternately spliced isoforms. In the rat pituitary, a truncated, tissue-specific variant of ERalpha, called TERP-1, has been identified and found able to modulate ERalpha and ERbeta activity. So far, its pattern of expression and hormonal regulation have been mostly studied in females. The present study was designed to analyze the pattern of expression of TERP-1 mRNA in the male rat pituitary at different stages of postnatal development, and to evaluate the impact of neonatal imprinting and estrogen treatment upon TERP-1 expression in the male pituitary. Assessment of TERP-1 mRNA levels by semi-quantitative RT-PCR, using a variant-specific primer pair, revealed that TERP-1 is also expressed in the male rat pituitary. Relative mRNA expression levels changed markedly during postnatal development, with moderate expression of the TERP-1 transcript at birth, barely detectable levels during the infantile-prepubertal period, and maximal values in adulthood. Expression of TERP-1 was sensitive to neonatal estrogen exposure, which resulted in a significant, persistent increase in mRNA levels from the infantile period until puberty. This phenomenon was not mimicked by neonatal blockade of endogenous GnRH. In addition, estrogen was able to acutely up-regulate pituitary TERP-1 mRNA expression levels in prepubertal (30-day-old) and adult (75-day-old) males. Interestingly, neonatal imprinting as well as acute estrogen treatment resulted in opposite effects on TERP-1 and full-length ERalpha and ERbeta transcripts, the latter being decreased under both conditions. In conclusion, our data indicate that TERP-1 mRNA is expressed in a developmentally regulated manner in the male rat

Expression pattern of G protein‑coupled estrogen receptor 1 (GPER) in human cumulus granulosa cells (CGCs) of patients with PCOS.

PubMed

Zang, Lili; Zhang, Quan; Zhou, Yi; Zhao, Yan; Lu, Linlin; Jiang, Zhou; Peng, Zhen; Zou, Shuhua

2016-06-01

Estradiol mediates its actions by binding to classical nuclear receptors, estrogen receptor α (ER-α) and estrogen receptor β (ER-β), and the non-classical G protein-coupled estrogen receptor 1(GPER). Several gene knockdown models have shown the importance of the receptors for growth of the oocyte and for ovulation. The aim of our study was to identify the pattern of GPER expression in human cumulus granulosa cells (CGCs) from ovarian follicles at different stages of oocyte maturation, and the differences of GPER expression between polycystic ovary syndrome (PCOS) patients and non-PCOS women. Thirty-eight cases of PCOS patients and a control group of thirty-two infertile women without PCOS were used in this study. GPER's location in CGCs was investigated by immunohistochemistry. Quantitative RT-PCR and western blot were used to identify the quantify GPER expression. Here we demonstrated that GPER was expressed in CGCs of both PCOS patients and non-PCOS women, and the expression of GPER was decreased significantly during oocyte maturation. But the expression levels of GPER in CGCs of PCOS patients and non-PCOS women were not significantly different. The data indicate that GPER may play a role during human oocyte maturation through its action in cumulus granulosa cells. AMHRIIs: anti-Mullerian hormone type II receptors; BMI: body mass index; CGCs: cumulus granulosa cells; COH: controlled ovarian hyperstimulation; E2: estradiol; EGFR: epidermal growth factor receptor; ER-α: estrogen receptor; ER-β: estrogen receptor β; FF: follicular fluid; FSH: follicle-stimulating hormone; GCs: granulosa cells; GPER: G protein-coupled estrogen receptor 1; GV: germinal vesicle; GVBD: germinal vesicle breakdown; HCG: human chorionic gonadotropin; IRS: immunoreactive score; IVF-ET: in vitro fertilization and embryo transfer; MI: metaphase I; MII: metaphase II; MAPK: mitogen-activated protein kinase; OCCCs: oocyte corona cumulus complexes; PCOS: polycystic ovarian syndrome; q

Estrogen and estrogen receptor alpha promotes malignancy and osteoblastic tumorigenesis in prostate cancer.

PubMed

Mishra, Sweta; Tai, Qin; Gu, Xiang; Schmitz, James; Poullard, Ashley; Fajardo, Roberto J; Mahalingam, Devalingam; Chen, Xiaodong; Zhu, Xueqiong; Sun, Lu-Zhe

2015-12-29

The role of estrogen signaling in regulating prostate tumorigenesis is relatively underexplored. Although, an increasing body of evidence has linked estrogen receptor beta (ERß) to prostate cancer, the function of estrogen receptor alpha (ERα) in prostate cancer is not very well studied. We have discovered a novel role of ERα in the pathogenesis of prostate tumors. Here, we show that prostate cancer cells express ERα and estrogen induces oncogenic properties in prostate cancer cells through ERα. Importantly, ERα knockdown in the human prostate cancer PacMetUT1 cells as well as pharmacological inhibition of ERα with ICI 182,780 inhibited osteoblastic lesion formation and lung metastasis in vivo. Co-culture of pre-osteoblasts with cancer cells showed a significant induction of osteogenic markers in the pre-osteoblasts, which was attenuated by knockdown of ERα in cancer cells suggesting that estrogen/ERα signaling promotes crosstalk between cancer and osteoblastic progenitors to stimulate osteoblastic tumorigenesis. These results suggest that ERα expression in prostate cancer cells is essential for osteoblastic lesion formation and lung metastasis. Thus, inhibition of ERα signaling in prostate cancer cells may be a novel therapeutic strategy to inhibit the osteoblastic lesion development as well as lung metastasis in patients with advanced prostate cancer.

Histone H2A.Z is essential for estrogen receptor signaling

PubMed Central

Gévry, Nicolas; Hardy, Sara; Jacques, Pierre-Étienne; Laflamme, Liette; Svotelis, Amy; Robert, François; Gaudreau, Luc

2009-01-01

Incorporation of H2A.Z into the chromatin of inactive promoters has been shown to poise genes for their expression. Here we provide strong evidence that H2A.Z is incorporated into the promoter regions of estrogen receptor (ERα) target genes only upon gene induction, and that, in a cyclic pattern. Moreover, members of the human H2A.Z-depositing complex, p400, also follow the same gene recruitment kinetics as H2A.Z. Importantly, cellular depletion of H2A.Z or p400 leads to a severe defect in estrogen signaling, including loss of estrogen-specific cell proliferation. We find that incorporation of H2A.Z within TFF1 promoter chromatin allows nucleosomes to adopt preferential positions along the DNA translational axis. Finally, we provide evidence that H2A.Z is essential to allow estrogen-responsive enhancer function. Taken together, our results provide strong mechanistic insight into how H2A.Z regulates ERα-mediated gene expression and provide a novel link between H2A.Z–p400 and ERα-dependent gene regulation and enhancer function. PMID:19515975

Evaluation of the Biological Activity of Opuntia ficus indica as a Tissue- and Estrogen Receptor Subtype-Selective Modulator.

PubMed

An, Byoung Ha; Jeong, Hyesoo; Zhou, Wenmei; Liu, Xiyuan; Kim, Soolin; Jang, Chang Young; Kim, Hyun-Sook; Sohn, Johann; Park, Hye-Jin; Sung, Na-Hye; Hong, Cheol Yi; Chang, Minsun

2016-06-01

Phytoestrogens are selective estrogen receptor modulators (SERMs) with potential for use in hormone replacement therapy (HRT) to relieve peri/postmenopausal symptoms. This study was aimed at elucidating the molecular mechanisms underlying the SERM properties of the extract of Korean-grown Opuntia ficus-indica (KOFI). The KOFI extract induced estrogen response element (ERE)-driven transcription in breast and endometrial cancer cell lines and the expression of endogenous estrogen-responsive genes in breast cancer cells. The flavonoid content of different KOFI preparations affected ERE-luciferase activities, implying that the flavonoid composition likely mediated the estrogenic activities in cells. Oral administration of KOFI decreased the weight gain and levels of both serum glucose and triglyceride in ovariectomized (OVX) rats. Finally, KOFI had an inhibitory effect on the 17β-estradiol-induced proliferation of the endometrial epithelium in OVX rats. Our data demonstrate that KOFI exhibited SERM activity with no uterotrophic side effects. Therefore, KOFI alone or in combination with other botanical supplements, vitamins, or minerals may be an effective and safe alternative active ingredient to HRTs, for the management of postmenopausal symptoms. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

Estrogens and Progesterone Promote Persistent CCND1 Gene Activation during G1 by Inducing Transcriptional Derepression via c-Jun/c-Fos/Estrogen Receptor (Progesterone Receptor) Complex Assembly to a Distal Regulatory Element and Recruitment of Cyclin D1 to Its Own Gene Promoter

PubMed Central

Cicatiello, Luigi; Addeo, Raffaele; Sasso, Annarita; Altucci, Lucia; Petrizzi, Valeria Belsito; Borgo, Raphaelle; Cancemi, Massimo; Caporali, Simona; Caristi, Silvana; Scafoglio, Claudio; Teti, Diana; Bresciani, Francesco; Perillo, Bruno; Weisz, Alessandro

2004-01-01

Transcriptional activation of the cyclin D1 gene (CCND1) plays a pivotal role in G1-phase progression, which is thereby controlled by multiple regulatory factors, including nuclear receptors (NRs). Appropriate CCND1 gene activity is essential for normal development and physiology of the mammary gland, where it is regulated by ovarian steroids through a mechanism(s) that is not fully elucidated. We report here that CCND1 promoter activation by estrogens in human breast cancer cells is mediated by recruitment of a c-Jun/c-Fos/estrogen receptor α complex to the tetradecanoyl phorbol acetate-responsive element of the gene, together with Oct-1 to a site immediately adjacent. This process coincides with the release from the same DNA region of a transcriptional repressor complex including Yin-Yang 1 (YY1) and histone deacetylase 1 and is sufficient to induce the assembly of the basal transcription machinery on the promoter and to lead to initial cyclin D1 accumulation in the cell. Later on in estrogen stimulation, the cyclin D1/Cdk4 holoenzyme associates with the CCND1 promoter, where E2F and pRb can also be found, contributing to the long-lasting gene enhancement required to drive G1-phase completion. Interestingly, progesterone triggers similar regulatory events through its own NRs, suggesting that the gene regulation cascade described here represents a crossroad for the transcriptional control of G1-phase progression by different classes of NRs. PMID:15282324

Immune-Specific Expression and Estrogenic Regulation of the Four Estrogen Receptor Isoforms in Female Rainbow Trout (Oncorhynchus mykiss).

PubMed

Casanova-Nakayama, Ayako; Wernicke von Siebenthal, Elena; Kropf, Christian; Oldenberg, Elisabeth; Segner, Helmut

2018-03-21

liver and gonads. The correlation between ER gene transcript numbers and serum E2 concentrations was only moderate to low. In conclusion, the low mRNA numbers of nuclear ER in the trout immune system, together with their limited estrogen-responsiveness, suggest that the known estrogen actions on trout immunity may be not primarily mediated through genomic actions, but may involve other mechanisms, such as non-genomic pathways or indirect effects.

MODELING THE EFFECTS OF FLEXIBILITY ON THE BINDING OF ENVIRONMENTAL ESTROGENS TO THE ESTROGEN RECEPTOR

EPA Science Inventory

Modeling the effects of flexibility on the binding of environmental estrogens to the estrogen receptor
There are many reports of environmental endocrine disruption in the literature, yet it has been difficult to identify the specific chemicals responsible for these effects. ...

Estrogen Regulates Bone Turnover by Targeting RANKL Expression in Bone Lining Cells.

PubMed

Streicher, Carmen; Heyny, Alexandra; Andrukhova, Olena; Haigl, Barbara; Slavic, Svetlana; Schüler, Christiane; Kollmann, Karoline; Kantner, Ingrid; Sexl, Veronika; Kleiter, Miriam; Hofbauer, Lorenz C; Kostenuik, Paul J; Erben, Reinhold G

2017-07-25

Estrogen is critical for skeletal homeostasis and regulates bone remodeling, in part, by modulating the expression of receptor activator of NF-κB ligand (RANKL), an essential cytokine for bone resorption by osteoclasts. RANKL can be produced by a variety of hematopoietic (e.g. T and B-cell) and mesenchymal (osteoblast lineage, chondrocyte) cell types. The cellular mechanisms by which estrogen acts on bone are still a matter of controversy. By using murine reconstitution models that allow for selective deletion of estrogen receptor-alpha (ERα) or selective inhibition of RANKL in hematopoietic vs. mesenchymal cells, in conjunction with in situ expression profiling in bone cells, we identified bone lining cells as important gatekeepers of estrogen-controlled bone resorption. Our data indicate that the increase in bone resorption observed in states of estrogen deficiency in mice is mainly caused by lack of ERα-mediated suppression of RANKL expression in bone lining cells.

Low Concentrations of o,p’-DDT Inhibit Gene Expression and Prostaglandin Synthesis by Estrogen Receptor-Independent Mechanism in Rat Ovarian Cells

PubMed Central

Liu, Jing; Zhao, Meirong; Zhuang, Shulin; Yang, Yan; Yang, Ye; Liu, Weiping

2012-01-01

o,p’-DDT is an infamous xenoestrogen as well as a ubiquitous and persistent pollutant. Biomonitoring studies show that women have been internally exposed to o,p’-DDT at range of 0.3–500 ng/g (8.46×10−10 M−1.41×10−6 M) in blood and other tissues. However, very limited studies have investigated the biological effects and mechanism(s) of o,p’-DDT at levels equal to or lower than current exposure levels in human. In this study, using primary cultures of rat ovarian granulosa cells, we determined that very low doses of o,p’-DDT (10−12−10−8 M) suppressed the expression of ovarian genes and production of prostaglandin E2 (PGE2). In vivo experiments consistently demonstrated that o,p’-DDT at 0.5–1 mg/kg inhibited the gene expression and PGE2 levels in rat ovary. The surprising results from the receptor inhibitors studies showed that these inhibitory effects were exerted independently of either classical estrogen receptors (ERs) or G protein-coupled receptor 30 (GPR30). Instead, o,p’-DDT altered gene expression or hormone action via inhibiting the activation of protein kinase A (PKA), rather than protein kinase C (PKC). We further revealed that o,p’-DDT directly interfered with the PKA catalytic subunit. Our novel findings support the hypothesis that exposure to low concentrations of o,p’-DDT alters gene expression and hormone synthesis through signaling mediators beyond receptor binding, and imply that the current exposure levels of o,p’-DDT observed in the population likely poses a health risk to female reproduction. PMID:23209616

Estrogen rapidly enhances incisional pain of ovariectomized rats primarily through the G protein-coupled estrogen receptor.

PubMed

An, Guanghui; Li, Wenhui; Yan, Tao; Li, Shitong

2014-06-11

It has become increasingly apparent that the pain threshold of females and males varies in an estrogen dependent manner. To investigate the modulation of pain by estrogen and the molecular mechanisms involved in this process. A total of 48 rats were ovariectomized (OVX). At 14 and 20 days after OVX, rats were divided into eight groups: groups 1-4 were administered drugs intravenously (IV); groups 5-8 were administered through intrathecal (IT) catheter. Hind paw incision was made in all animals to determine incisional pain. Paw withdraw threshold (PWT) was tested prior to and 24 h after incision. The test drugs were applied 24 h after the incision. Rats were either IV or IT administered with: 17-β-estradiol (E2), G protein-coupled estrogen receptor (GPER)-selective agonist (G1), GPER-selective antagonist (G15) and E2 (G15+E2), or solvent. Before and 30 min after IV drug administration and 20 min during the IT catheter administration, PWT was tested and recorded. 24 h after incisional surgery, the PWT of all rats significantly decreased. Both in the IV group and IT group: administration of E2 and G1 significantly decreased PWT. Neither administration of G15+E2 nor solvent significantly changed PWT. Estrogen causes rapid reduction in the mechanical pain threshold of OVX rats via GPER.

Estrogen supports urothelial defense mechanisms.

PubMed

Lüthje, Petra; Brauner, Hanna; Ramos, Nubia L; Ovregaard, Amanda; Gläser, Regine; Hirschberg, Angelica Lindén; Aspenström, Pontus; Brauner, Annelie

2013-06-19

Epidemiological data imply a role of estrogen in the pathogenesis of urinary tract infections (UTIs), although the underlying mechanisms are not well understood. However, it is thought that estrogen supplementation after menopause decreases the risk of recurrent infections. We sought to investigate the influence of estrogen on host-pathogen interactions and the consequences for UTI pathogenesis. We analyzed urothelial cells from menstruating and postmenopausal women before and after a 2-week period of estrogen supplementation, and also studied the influence of estradiol during Escherichia coli UTI in a mouse infection model. Important findings were confirmed in two human urothelial cell lines. We identified two epithelial defense mechanisms modulated by estrogen. Estrogen induced the expression of antimicrobial peptides, thereby enhancing the antimicrobial capacity of the urothelium and restricting bacterial multiplication. In addition, estrogen promoted the expression and redistribution of cell-cell contact-associated proteins, thereby strengthening the epithelial integrity and preventing excessive loss of superficial cells during infection. These two effects together may prevent bacteria from reaching deeper layers of the urinary tract epithelium and developing reservoirs that can serve as a source for recurrent infections. Thus, this study presents some underlying mechanisms for the beneficial effect of estradiol after menopause and supports the application of estrogen in postmenopausal women suffering from recurrent UTI.

Interplay between estrogen receptor and AKT in Estradiol-induced alternative splicing

PubMed Central

2013-01-01

Background Alternative splicing is critical for generating complex proteomes in response to extracellular signals. Nuclear receptors including estrogen receptor alpha (ERα) and their ligands promote alternative splicing. The endogenous targets of ERα:estradiol (E2)-mediated alternative splicing and the influence of extracellular kinases that phosphorylate ERα on E2-induced splicing are unknown. Methods MCF-7 and its anti-estrogen derivatives were used for the majority of the assays. CD44 mini gene was used to measure the effect of E2 and AKT on alternative splicing. ExonHit array analysis was performed to identify E2 and AKT-regulated endogenous alternatively spliced apoptosis-related genes. Quantitative reverse transcription polymerase chain reaction was performed to verify alternative splicing. ERα binding to alternatively spliced genes was verified by chromatin immunoprecipitation assay. Bromodeoxyuridine incorporation-ELISA and Annexin V labeling assays were done to measure cell proliferation and apoptosis, respectively. Results We identified the targets of E2-induced alternative splicing and deconstructed some of the mechanisms surrounding E2-induced splicing by combining splice array with ERα cistrome and gene expression array. E2-induced alternatively spliced genes fall into at least two subgroups: coupled to E2-regulated transcription and ERα binding to the gene without an effect on rate of transcription. Further, AKT, which phosphorylates both ERα and splicing factors, influenced ERα:E2 dependent splicing in a gene-specific manner. Genes that are alternatively spliced include FAS/CD95, FGFR2, and AXIN-1. E2 increased the expression of FGFR2 C1 isoform but reduced C3 isoform at mRNA level. E2-induced alternative splicing of FAS and FGFR2 in MCF-7 cells correlated with resistance to FAS activation-induced apoptosis and response to keratinocyte growth factor (KGF), respectively. Resistance of MCF-7 breast cancer cells to the anti-estrogen tamoxifen

The estrogen receptor alpha nuclear localization sequence is critical for fulvestrant-induced degradation of the receptor.

PubMed

Casa, Angelo J; Hochbaum, Daniel; Sreekumar, Sreeja; Oesterreich, Steffi; Lee, Adrian V

2015-11-05

Fulvestrant, a selective estrogen receptor down-regulator (SERD) is a pure competitive antagonist of estrogen receptor alpha (ERα). Fulvestrant binds ERα and reduces the receptor's half-life by increasing protein turnover, however, its mechanism of action is not fully understood. In this study, we show that removal of the ERα nuclear localization sequence (ERΔNLS) resulted in a predominantly cytoplasmic ERα that was degraded in response to 17-β-estradiol (E2) but was resistant to degradation by fulvestrant. ERΔNLS bound the ligands and exhibited receptor interaction similar to ERα, indicating that the lack of degradation was not due to disruption of these processes. Forcing ERΔNLS into the nucleus with a heterologous SV40-NLS did not restore degradation, suggesting that the NLS domain itself, and not merely receptor localization, is critical for fulvestrant-induced ERα degradation. Indeed, cloning of the endogenous ERα NLS onto the N-terminus of ERΔNLS significantly restored both its nuclear localization and turnover in response to fulvestrant. Moreover, mutation of the sumoylation targets K266 and K268 within the NLS impaired fulvestrant-induced ERα degradation. In conclusion, our study provides evidence for the unique role of the ERα NLS in fulvestrant-induced degradation of the receptor. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Mechanism of phytoestrogen puerarin-mediated cytoprotection following oxidative injury: Estrogen receptor-dependent up-regulation of PI3K/Akt and HO-1

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hwang, Yong Pil; Jeong, Hye Gwang

2008-12-15

Phytoestrogens are polyphenolic non-steroidal plant compounds with estrogen-like biological activity. The phytoestrogen puerarin, the main isoflavone glycoside found in the root of Pueraria lobata, has been used for various medicinal purposes in traditional Chinese medicines for thousands of years. Recent studies have indicated that the estrogen receptor (ER), through interaction with p85, regulates phosphoinositide 3-kinase (PI3K) activity, revealing a physiologic, non-nuclear function of ER that may be relevant in cytoprotection. In this study, we demonstrate that the phytoestrogen puerarin inhibits tert-butyl hydroperoxide (t-BHP)-induced oxidative injury via an ER-dependent G{beta}1/PI3K/Akt and heme oxygenase-1 (HO-1) pathway. Pretreatment of Hepa1c1c7 and HepG2 cellsmore » with puerarin significantly reduced t-BHP-induced caspase-3 activation and subsequent cell death. Also, puerarin up-regulated HO-1 expression and this expression conferred cytoprotection against oxidative injury induced by t-BHP. Moreover, puerarin induced Nrf2 nuclear translocation, which is upstream of puerarin-induced HO-1 expression, and PI3K activation, a pathway that is involved in induced Nrf2 nuclear translocation, HO-1 expression and cytoprotection. Puerarin-induced up-regulation of HO-1 and cytoprotection against t-BHP were abolished by silencing Nrf2 expression with specific siRNA. Also, puerarin-mediated increases in PI3K activation and HO-1 induction were reversed by co-treatment with ICI 182,780 and pertussis toxin. Taken together, these results suggest that puerarin augments cellular antioxidant defense capacity through ER-dependent HO-1 induction via the G{beta}1/PI3K/Akt-Nrf2 signaling pathway, thereby protecting cells from oxidative stress.« less

Inhibition of estrogen-responsive gene activation by the retinoid X receptor beta: evidence for multiple inhibitory pathways.

PubMed

Segars, J H; Marks, M S; Hirschfeld, S; Driggers, P H; Martinez, E; Grippo, J F; Brown, M; Wahli, W; Ozato, K

1993-04-01

The retinoid X receptor beta (RXR beta; H-2RIIBP) forms heterodimers with various nuclear hormone receptors and binds multiple hormone response elements, including the estrogen response element (ERE). In this report, we show that endogenous RXR beta contributes to ERE binding activity in nuclear extracts of the human breast cancer cell line MCF-7. To define a possible regulatory role of RXR beta regarding estrogen-responsive transcription in breast cancer cells, RXR beta and a reporter gene driven by the vitellogenin A2 ERE were transfected into estrogen-treated MCF-7 cells. RXR beta inhibited ERE-driven reporter activity in a dose-dependent and element-specific fashion. This inhibition occurred in the absence of the RXR ligand 9-cis retinoic acid. The RXR beta-induced inhibition was specific for estrogen receptor (ER)-mediated ERE activation because inhibition was observed in ER-negative MDA-MB-231 cells only following transfection of the estrogen-activated ER. No inhibition of the basal reporter activity was observed. The inhibition was not caused by simple competition of RXR beta with the ER for ERE binding, since deletion mutants retaining DNA binding activity but lacking the N-terminal or C-terminal domain failed to inhibit reporter activity. In addition, cross-linking studies indicated the presence of an auxiliary nuclear factor present in MCF-7 cells that contributed to RXR beta binding of the ERE. Studies using known heterodimerization partners of RXR beta confirmed that RXR beta/triiodothyronine receptor alpha heterodimers avidly bind the ERE but revealed the existence of another triiodothyronine-independent pathway of ERE inhibition. These results indicate that estrogen-responsive genes may be negatively regulated by RXR beta through two distinct pathways.

Isoliquiritigenin exhibits anti-proliferative properties in the pituitary independent of estrogen receptor function

DOE Office of Scientific and Technical Information (OSTI.GOV)

Weis, Karen E.; Raetzman, Lori T., E-mail: raetzma

The plant flavonoid isoliquiritigenin (ISL) is a botanical estrogen widely taken as an herbal supplement to ease the symptoms of menopause. ISL has been also shown to have anti-tumor properties in a number of cancer cell backgrounds. However, the effects of ISL on normal cells are less well known and virtually unstudied in the context of the pituitary gland. We have established a pituitary explant culture model to screen chemical agents for gene expression changes within the pituitary gland during a period of active proliferation and differentiation. Using this whole-organ culture system we found ISL to be weakly estrogenic basedmore » on its ability to induce Cckar mRNA expression, an estrogen receptor (ER) mediated gene. Using a range of ISL from 200 nM to 200 μM, we discovered that ISL promoted cell proliferation at a low concentration, yet potently inhibited proliferation at the highest concentration. ICI 182,780 failed to antagonize ISL's repression of pituitary cell proliferation, indicating the effect is independent of ER signaling. Coincident with a decrease in proliferating cells, we observed down-regulation of transcript for cyclin D2 and E2 and a strong induction of mRNA and protein for the cyclin dependent kinase inhibitor Cdkn1a (p21). Importantly, high dose ISL did not alter the balance of progenitor vs. differentiated cell types within the pituitary explants and they seemed otherwise healthy; however, TUNEL staining revealed an increase in apoptotic cell death in ISL treated cultures. Our results merit further examination of ISL as an anti-tumor agent in the pituitary gland. - Highlights: • Isoliquiritigenin possesses weak estrogenic activity based on induction of Cckar. • ISL can be anti-proliferative in pituitary explants without altering cell lineages. • Anti-proliferative behavior of ISL is not estrogen receptor mediated. • ISL induces p21 expression leading to cell cycle arrest and apoptosis.« less

Tamoxifen and estradiol improved locomotor function and increased spared tissue in rats after spinal cord injury: their antioxidant effect and role of estrogen receptor alpha.

PubMed

Mosquera, Laurivette; Colón, Jennifer M; Santiago, José M; Torrado, Aranza I; Meléndez, Margarita; Segarra, Annabell C; Rodríguez-Orengo, José F; Miranda, Jorge D

2014-05-02

17β-Estradiol is a multi-active steroid that imparts neuroprotection via diverse mechanisms of action. However, its role as a neuroprotective agent after spinal cord injury (SCI), or the involvement of the estrogen receptor-alpha (ER-α) in locomotor recovery, is still a subject of much debate. In this study, we evaluated the effects of estradiol and of Tamoxifen (an estrogen receptor mixed agonist/antagonist) on locomotor recovery following SCI. To control estradiol cyclical variability, ovariectomized female rats received empty or estradiol filled implants, prior to a moderate contusion to the spinal cord. Estradiol improved locomotor function at 7, 14, 21, and 28 days post injury (DPI), when compared to control groups (measured with the BBB open field test). This effect was ER-α mediated, because functional recovery was blocked with an ER-α antagonist. We also observed that ER-α was up-regulated after SCI. Long-term treatment (28 DPI) with estradiol and Tamoxifen reduced the extent of the lesion cavity, an effect also mediated by ER-α. The antioxidant effects of estradiol were seen acutely at 2 DPI but not at 28 DPI, and this acute effect was not receptor mediated. Rats treated with Tamoxifen recovered some locomotor activity at 21 and 28 DPI, which could be related to the antioxidant protection seen at these time points. These results show that estradiol improves functional outcome, and these protective effects are mediated by the ER-α dependent and independent-mechanisms. Tamoxifen׳s effects during late stages of SCI support the use of this drug as a long-term alternative treatment for this condition. Copyright © 2014 Elsevier B.V. All rights reserved.

Evidence for estrogen receptor beta-selective activity of Vitex agnus-castus and isolated flavones.

PubMed

Jarry, Hubertus; Spengler, Barbara; Porzel, Andrea; Schmidt, Juergen; Wuttke, Wolfgang; Christoffel, Volker

2003-10-01

Recent cell culture experiments indicated that extracts of Vitex agnus-castus (VAC) may contain yet unidentified phytoestrogens. Estrogenic actions are mediated via estrogen receptors (ER). To investigate whether VAC compounds bind to the currently known isoforms ERalpha or ERss, ligand binding assays (LBA) were performed. Subtype specific ER-LBA revealed a binding of VAC to ERss only. To isolate the ERss-selective compounds, the extract was fractionated by bio-guidance. The flavonoid apigenin was isolated and identified as the most active ERss-selective phytoestrogen in VAC. Other isolated compounds were vitexin and penduletin. These data demonstrate that the phytoestrogens in VAC are ERss-selective.

Progesterone receptor isoforms, agonists and antagonists differentially reprogram estrogen signaling

PubMed Central

Singhal, Hari; Greene, Marianne E.; Zarnke, Allison L.; Laine, Muriel; Al Abosy, Rose; Chang, Ya-Fang; Dembo, Anna G.; Schoenfelt, Kelly; Vadhi, Raga; Qiu, Xintao; Rao, Prakash; Santhamma, Bindu; Nair, Hareesh B.; Nickisch, Klaus J.; Long, Henry W.; Becker, Lev; Brown, Myles; Greene, Geoffrey L.

2018-01-01

Major roadblocks to developing effective progesterone receptor (PR)-targeted therapies in breast cancer include the lack of highly-specific PR modulators, a poor understanding of the pro- or anti-tumorigenic networks for PR isoforms and ligands, and an incomplete understanding of the cross talk between PR and estrogen receptor (ER) signaling. Through genomic analyses of xenografts treated with various clinically-relevant ER and PR-targeting drugs, we describe how the activation or inhibition of PR differentially reprograms estrogen signaling, resulting in the segregation of transcriptomes into separate PR agonist and antagonist-mediated groups. These findings address an ongoing controversy regarding the clinical utility of PR agonists and antagonists, alone or in combination with tamoxifen, for breast cancer management. Additionally, the two PR isoforms PRA and PRB, bind distinct but overlapping genomic sites and interact with different sets of co-regulators to differentially modulate estrogen signaling to be either pro- or anti-tumorigenic. Of the two isoforms, PRA inhibited gene expression and ER chromatin binding significantly more than PRB. Differential gene expression was observed in PRA and PRB-rich patient tumors and PRA-rich gene signatures had poorer survival outcomes. In support of antiprogestin responsiveness of PRA-rich tumors, gene signatures associated with PR antagonists, but not PR agonists, predicted better survival outcomes. The better patient survival associated with PR antagonists versus PR agonists treatments was further reflected in the higher in vivo anti-tumor activity of therapies that combine tamoxifen with PR antagonists and modulators. This study suggests that distinguishing common effects observed due to concomitant interaction of another receptor with its ligand (agonist or antagonist), from unique isoform and ligand-specific effects will inform the development of biomarkers for patient selection and translation of PR

Expression of estrogen, estrogen related and androgen receptors in adrenal cortex of intact adult male and female rats.

PubMed

Trejter, Marcin; Jopek, Karol; Celichowski, Piotr; Tyczewska, Marianna; Malendowicz, Ludwik K; Rucinski, Marcin

2015-01-01

RNA. In adrenals of adult male and female rats expression levels of estrogen-related receptors ERRα and ERRβ were similar, and only in the ZF/R of female rats ERRγ expression levels were significantly higher than in males. We also analyzed expression profile of three isoforms of steroid 5α-reductase (Srd5a1, Srd5a2 and Srd5a3) and aromatase (Cyp19a1) and expression levels of all these genes were similar in ZG and ZF/R of male and female rats. In contrast to Affymetrix microarray data QPCR revealed higher expression levels of AR gene in adrenal glands of the male rats. In adrenals of both sexes expression levels of ERa, ERb, non-genomic GPR30 (GPER-1), ERR α and ERRβ receptors were comparable. The obtained results suggest that acute steroidogenic effect of estrogens on corticosteroid secretion may be mediated by non-genomic GPR30.

Tristetraprolin Represses Estrogen Receptor α Transactivation in Breast Cancer Cells*

PubMed Central

Barrios-García, Tonatiuh; Tecalco-Cruz, Angeles; Gómez-Romero, Vania; Reyes-Carmona, Sandra; Meneses-Morales, Iván; León-Del-Río, Alfonso

2014-01-01

Estrogen receptor α (ERα) mediates the effects of 17β-estradiol (E2) in normal mammary gland, and it is a key participant in breast cancer tumor development. ERα transactivation activity is mediated by the synergistic interaction of two domains designated AF1 and AF2. The function of AF2 is to recruit coactivator and corepressor proteins that allow ERα to oscillate between the roles of transcriptional activator and repressor. In contrast, the mechanism responsible for AF-1 transcriptional activity is not completely understood. In this study, we identified tristetraproline (TTP) as a novel ERα-associated protein. TTP expression in MCF7 cells repressed ERα transactivation and reduced MCF7 cell proliferation and the ability of the cells to form tumors in a mouse model. We show that TTP transcriptional activity is mediated through its recruitment to the promoter region of ERα target genes and its interaction with histone deacetylases, in particular with HDAC1. TTP expression attenuates the coactivating activity of SRC-1, suggesting that exchange between TTP and other coactivators may play an important role in fine-tuning ERα transactivation. These results indicate that TTP acts as a bona fide ERα corepressor and suggest that this protein may be a contributing factor in the development of E2-dependent tumors in breast cancer. PMID:24737323

Transcriptional corepressor SMILE recruits SIRT1 to inhibit nuclear receptor estrogen receptor-related receptor gamma transactivation.

PubMed

Xie, Yuan-Bin; Park, Jeong-Hoh; Kim, Don-Kyu; Hwang, Jung Hwan; Oh, Sangmi; Park, Seung Bum; Shong, Minho; Lee, In-Kyu; Choi, Hueng-Sik

2009-10-16

SMILE (small heterodimer partner interacting leucine zipper protein) has been identified as a corepressor of the glucocorticoid receptor, constitutive androstane receptor, and hepatocyte nuclear factor 4alpha. Here we show that SMILE also represses estrogen receptor-related receptor gamma (ERRgamma) transactivation. Knockdown of SMILE gene expression increases ERRgamma activity. SMILE directly interacts with ERRgamma in vitro and in vivo. Domain mapping analysis showed that SMILE binds to the AF2 domain of ERRgamma. SMILE represses ERRgamma transactivation partially through competition with coactivators PGC-1alpha, PGC-1beta, and GRIP1. Interestingly, the repression of SMILE on ERRgamma is released by SIRT1 inhibitors, a catalytically inactive SIRT1 mutant, and SIRT1 small interfering RNA but not by histone protein deacetylase inhibitor. In vivo glutathione S-transferase pulldown and coimmunoprecipitation assays validated that SMILE physically interacts with SIRT1. Furthermore, the ERRgamma inverse agonist GSK5182 enhances the interaction of SMILE with ERRgamma and SMILE-mediated repression. Knockdown of SMILE or SIRT1 blocks the repressive effect of GSK5182. Moreover, chromatin immunoprecipitation assays revealed that GSK5182 augments the association of SMILE and SIRT1 on the promoter of the ERRgamma target PDK4. GSK5182 and adenoviral overexpression of SMILE cooperate to repress ERRgamma-induced PDK4 gene expression, and this repression is released by overexpression of a catalytically defective SIRT1 mutant. Finally, we demonstrated that ERRgamma regulates SMILE gene expression, which in turn inhibits ERRgamma. Overall, these findings implicate SMILE as a novel corepressor of ERRgamma and recruitment of SIRT1 as a novel repressive mechanism for SMILE and ERRgamma inverse agonist.

Species comparisons in molecular and functional attributes of the androgen and estrogen receptor

EPA Science Inventory

While endocrine disrupting compounds (EDCs) have the potential to act via several mechanisms of action, one of the most widely studied is the ability of environmental chemicals to interact directly with either the estrogen (ER) or androgen receptor (AR). In vitro screening assay...

Tetrahydroisoquinoline alkaloids mimic direct but not receptor-mediated inhibitory effects of estrogens and phytoestrogens on testicular endocrine function. Possible significance for Leydig cell insufficiency in alcohol addiction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stammel, W.; Thomas, H.; Staib, W.

1991-01-01

Possible effects of various tetrahydroisoquinolines (TIQs) on rat testicular endocrine function were tested in vitro in order to prove whether these compounds may be mediators of the development of Leydig cell insufficiency. TIQ effects on different levels of regulation of testis function were compared in vitro with estrogen effects, since both classes of compounds have structural similarities. Gonadotropin-stimulated testosterone production by testicular Leydig cells was inhibited by tetrahydropapaveroline and isosalsoline, the IC{sub 50} values being comparable to those of estradiol, 2-hydroxyestradiol, and the phytoestrogens, coumestrol and genistein; salsolinol and salsoline were less effective, and salsolidine was ineffective. None of thesemore » TIQs interacted significantly with testicular estrogen receptor as analyzed by estradiol displacement. However, tetrahydropapaveroline, isosalsoline and salsolinol competitively inhibited substrate binding to cytochrome P45OXVII, with similar efficiency as the estrogens did; salsoline and salsolidine were again much less effective.« less

SIP1/NHERF2 enhances estrogen receptor alpha transactivation in breast cancer cells

PubMed Central

Meneses-Morales, Ivan; Tecalco-Cruz, Angeles C.; Barrios-García, Tonatiuh; Gómez-Romero, Vania; Trujillo-González, Isis; Reyes-Carmona, Sandra; García-Zepeda, Eduardo; Méndez-Enríquez, Erika; Cervantes-Roldán, Rafael; Pérez-Sánchez, Víctor; Recillas-Targa, Félix; Mohar-Betancourt, Alejandro; León-Del-Río, Alfonso

2014-01-01

The estrogen receptor alpha (ERα) is a ligand-activated transcription factor that possesses two activating domains designated AF-1 and AF-2 that mediate its transcriptional activity. The role of AF-2 is to recruit coregulator protein complexes capable of modifying chromatin condensation status. In contrast, the mechanism responsible for the ligand-independent AF-1 activity and for its synergistic functional interaction with AF-2 is unclear. In this study, we have identified the protein Na+/H+ Exchanger RegulatoryFactor 2 (NHERF2) as an ERα-associated coactivator that interacts predominantly with the AF-1 domain of the nuclear receptor. Overexpression of NHERF2 in breast cancer MCF7 cells produced an increase in ERα transactivation. Interestingly, the presence of SRC-1 in NHERF2 stably overexpressing MCF7 cells produced a synergistic increase in ERα activity. We show further that NHERF2 interacts with ERα and SRC-1 in the promoter region of ERα target genes. The binding of NHERF2 to ERα in MCF7 cells increased cell proliferation and the ability of MCF7 cells to form tumors in a mouse model. We analyzed the expression of NHERF2 in breast cancer tumors finding a 2- to 17-fold increase in its mRNA levels in 50% of the tumor samples compared to normal breast tissue. These results indicate that NHERF2 is a coactivator of ERα that may participate in the development of estrogen-dependent breast cancer tumors. PMID:24771346

Bisphenol A (BPA) binding on full-length architectures of estrogen receptor.

PubMed

Liu, Yaquan; Qu, Kaili; Hai, Ying; Zhao, Chunyan

2018-08-01

Previous research has shown that the major toxicity mechanism for many environment chemicals is binding with estrogen receptor (ER) and blocking endogenous estrogen access, including bisphenol A (BPA). However, the molecular level understanding the global consequence of BPA binding on the full-length architectures of ER is largely unknown, which is a necessary stage to evaluate estrogen-like toxicity of BPA. In the present work, the consequence of BPA on full-length architectures of ER was firstly modeled based on molecular dynamics, focusing on the cross communication between multi-domains including ligand binding domain (LBD) and DNA binding domain (DBD). The study proved consequence of BPA upon full-length ER structure was dependent on long-range communications between multiple protein domains. The allosteric effects occurring in LBD units could alter dimerization formation through a crucial change in residue-residue connections, which resulted in relaxation of DBD. It indicated BPA could present consequence on the full-size receptor, not only on the separate domains, but also on the cross communication among LBD, DBD, and DNA molecules. It might provide detailed insight into the knowledge about the structural characteristics of ER and its role in gene regulation, which eventually helped us evaluate the estrogen-like toxicity upon BPA binding with full-length ER. © 2018 Wiley Periodicals, Inc.

Estrogen receptor agonists/antagonists in breast cancer therapy: A critical review.

PubMed

Jameera Begam, A; Jubie, S; Nanjan, M J

2017-04-01

Estrogens display intriguing tissue selective action that is of great biomedical importance in the development of optimal therapeutics for the prevention and treatment of breast cancer. There are also strong evidences to show that both endogenous and exogenous estrogens are involved in the pathogenesis of breast cancer. Tamoxifen has been the only drug of choice for more than 30years to treat patients with estrogen related (ER) positive breast tumors. There is a need therefore, for identifying newer, potential and novel candidates for breast cancer. Keeping this in view, the present review focuses on selective estrogen receptor modulators and estrogen antagonists such as sulfatase and aromatase inhibitors involved in breast cancer therapy. A succinct and critical overview of the structure of estrogen receptors, their signaling and involvement in breast carcinogenesis are herein described. Copyright © 2017 Elsevier Inc. All rights reserved.

The role of estrogens for male bone health.

PubMed

Ohlsson, Claes; Vandenput, Liesbeth

2009-06-01

Sex steroids are important for the growth and maintenance of both the female and the male skeleton. However, the relative contribution of androgens versus estrogens in the regulation of the male skeleton is unclear. Experiments using mice with inactivated sex steroid receptors demonstrated that both activation of the estrogen receptor (ER)alpha and activation of the androgen receptor result in a stimulatory effect on both the cortical and trabecular bone mass in males. ERbeta is of no importance for the skeleton in male mice while it modulates the ERalpha-action on bone in female mice. Previous in vitro studies suggest that the membrane G protein-coupled receptor GPR30 also might be a functional ER. Our in vivo analyses of GPR30-inactivated mice revealed no function of GPR30 for estrogen-mediated effects on bone mass but it is required for normal regulation of the growth plate and estrogen-mediated insulin-secretion. Recent clinical evidence suggests that a threshold exists for estrogen effects on bone in men: rates of bone loss and fracture risk seem to be the highest in men with estradiol levels below this threshold. Taken together, even though these findings do not exclude an important role for testosterone in male skeletal homeostasis, it is now well-established that estrogens are important regulators of bone health in men.

Minireview: G Protein-Coupled Estrogen Receptor-1, GPER-1: Its Mechanism of Action and Role in Female Reproductive Cancer, Renal and Vascular Physiology

PubMed Central

Thomas, Peter

2012-01-01

Using cDNA cloning strategies commonly employed for G protein-coupled receptors (GPCR), GPCR-30 (GPR30), was isolated from mammalian cells before knowledge of its cognate ligand. GPR30 is evolutionarily conserved throughout the vertebrates. A broad literature suggests that GPR30 is a Gs-coupled heptahelical transmembrane receptor that promotes specific binding of naturally occurring and man-made estrogens but not cortisol, progesterone, or testosterone. Its “pregenomic” signaling actions are manifested by plasma membrane-associated actions familiar to GPCR, namely, stimulation of adenylyl cyclase and Gβγ-subunit protein-dependent release of membrane-tethered heparan bound epidermal growth factor. These facts regarding its mechanism of action have led to the formal renaming of this receptor to its current functional designate, G protein-coupled estrogen receptor (ER) (GPER)-1. Further insight regarding its biochemical action and physiological functions in vertebrates is derived from receptor knockdown studies and the use of selective agonists/antagonists that discriminate GPER-1 from the nuclear steroid hormone receptors, ERα and ERβ. GPER-1-selective agents have linked GPER-1 to physiological and pathological events regulated by estrogen action, including, but not limited to, the central nervous, immune, renal, reproductive, and cardiovascular systems. Moreover, immunohistochemical studies have shown a positive association between GPER-1 expression and progression of female reproductive cancer, a relationship that is diametrically opposed from ER. Unlike ER knockout mice, GPER-1 knockout mice are fertile and show no overt reproductive anomalies. However, they do exhibit thymic atrophy, impaired glucose tolerance, and altered bone growth. Here, we discuss the role of GPER-1 in female reproductive cancers as well as renal and vascular physiology. PMID:22495674

Minireview: G protein-coupled estrogen receptor-1, GPER-1: its mechanism of action and role in female reproductive cancer, renal and vascular physiology.

PubMed

Filardo, Edward J; Thomas, Peter

2012-07-01

Using cDNA cloning strategies commonly employed for G protein-coupled receptors (GPCR), GPCR-30 (GPR30), was isolated from mammalian cells before knowledge of its cognate ligand. GPR30 is evolutionarily conserved throughout the vertebrates. A broad literature suggests that GPR30 is a Gs-coupled heptahelical transmembrane receptor that promotes specific binding of naturally occurring and man-made estrogens but not cortisol, progesterone, or testosterone. Its "pregenomic" signaling actions are manifested by plasma membrane-associated actions familiar to GPCR, namely, stimulation of adenylyl cyclase and Gβγ-subunit protein-dependent release of membrane-tethered heparan bound epidermal growth factor. These facts regarding its mechanism of action have led to the formal renaming of this receptor to its current functional designate, G protein-coupled estrogen receptor (ER) (GPER)-1. Further insight regarding its biochemical action and physiological functions in vertebrates is derived from receptor knockdown studies and the use of selective agonists/antagonists that discriminate GPER-1 from the nuclear steroid hormone receptors, ERα and ERβ. GPER-1-selective agents have linked GPER-1 to physiological and pathological events regulated by estrogen action, including, but not limited to, the central nervous, immune, renal, reproductive, and cardiovascular systems. Moreover, immunohistochemical studies have shown a positive association between GPER-1 expression and progression of female reproductive cancer, a relationship that is diametrically opposed from ER. Unlike ER knockout mice, GPER-1 knockout mice are fertile and show no overt reproductive anomalies. However, they do exhibit thymic atrophy, impaired glucose tolerance, and altered bone growth. Here, we discuss the role of GPER-1 in female reproductive cancers as well as renal and vascular physiology.

SMILE, a new orphan nuclear receptor SHP-interacting protein, regulates SHP-repressed estrogen receptor transactivation.

PubMed

Xie, Yuan-Bin; Lee, Ok-Hee; Nedumaran, Balachandar; Seong, Hyun-A; Lee, Kyeong-Min; Ha, Hyunjung; Lee, In-Kyu; Yun, Yungdae; Choi, Hueng-Sik

2008-12-15

SHP (small heterodimer partner) is a well-known NR (nuclear receptor) co-regulator. In the present study, we have identified a new SHP-interacting protein, termed SMILE (SHP-interacting leucine zipper protein), which was previously designated as ZF (Zhangfei) via a yeast two-hybrid system. We have determined that the SMILE gene generates two isoforms [SMILE-L (long isoform of SMILE) and SMILE-S (short isoform of SMILE)]. Mutational analysis has demonstrated that the SMILE isoforms arise from the alternative usage of initiation codons. We have confirmed the in vivo interaction and co-localization of the SMILE isoforms and SHP. Domain-mapping analysis indicates that the entire N-terminus of SHP and the middle region of SMILE-L are involved in this interaction. Interestingly, the SMILE isoforms counteract the SHP repressive effect on the transactivation of ERs (estrogen receptors) in HEK-293T cells (human embryonic kidney cells expressing the large T-antigen of simian virus 40), but enhance the SHP-repressive effect in MCF-7, T47D and MDA-MB-435 cells. Knockdown of SMILE gene expression using siRNA (small interfering RNA) in MCF-7 cells increases ER-mediated transcriptional activity. Moreover, adenovirus-mediated overexpression of SMILE and SHP down-regulates estrogen-induced mRNA expression of the critical cell-cycle regulator E2F1. Collectively, these results indicate that SMILE isoforms regulate the inhibition of ER transactivation by SHP in a cell-type-specific manner and act as a novel transcriptional co-regulator in ER signalling.

Estrogen biology: new insights into GPER function and clinical opportunities.

PubMed

Prossnitz, Eric R; Barton, Matthias

2014-05-25

Estrogens play an important role in the regulation of normal physiology, aging and many disease states. Although the nuclear estrogen receptors have classically been described to function as ligand-activated transcription factors mediating genomic effects in hormonally regulated tissues, more recent studies reveal that estrogens also mediate rapid signaling events traditionally associated with G protein-coupled receptors. The G protein-coupled estrogen receptor GPER (formerly GPR30) has now become recognized as a major mediator of estrogen's rapid cellular effects throughout the body. With the discovery of selective synthetic ligands for GPER, both agonists and antagonists, as well as the use of GPER knockout mice, significant advances have been made in our understanding of GPER function at the cellular, tissue and organismal levels. In many instances, the protective/beneficial effects of estrogen are mimicked by selective GPER agonism and are absent or reduced in GPER knockout mice, suggesting an essential or at least parallel role for GPER in the actions of estrogen. In this review, we will discuss recent advances and our current understanding of the role of GPER and the activity of clinically used drugs, such as SERMs and SERDs, in physiology and disease. We will also highlight novel opportunities for clinical development towards GPER-targeted therapeutics, for molecular imaging, as well as for theranostic approaches and personalized medicine. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Estrogen Receptor Alpha Binding to ERE is Required for Full Tlr7- and Tlr9-Induced Inflammation

PubMed Central

Cunningham, Melissa A; Wirth, Jena R; Naga, Osama; Eudaly, Jackie; Gilkeson, Gary S

2014-01-01

We previously found that a maximum innate inflammatory response induced by stimulation of Toll-like receptors (TLRs) 3, 7 and 9 requires ERα, but does not require estrogen in multiple cell types from both control and lupus-prone mice. Given the estrogen-independence, we hypothesized that ERα mediates TLR signaling by tethering to, and enhancing, the activity of downstream transcription factors such as NFκB, rather than acting classically by binding EREs on target genes. To investigate the mechanism of ERα impact on TLR signaling, we utilized mice with a knock-in ERα mutant that is unable to bind ERE. After stimulation with TLR ligands, both ex vivo spleen cells and bone marrow-derived dendritic cells (BM-DCs) isolated from mutant ERα (“KIKO”) mice produced significantly less IL-6 compared with cells from wild-type (WT) littermates. These results suggest that ERα modulation of TLR signaling does indeed require ERE binding for its effect on the innate immune response. PMID:25061615

Niacin activates the G protein estrogen receptor (GPER)-mediated signalling.

PubMed

Santolla, Maria Francesca; De Francesco, Ernestina Marianna; Lappano, Rosamaria; Rosano, Camillo; Abonante, Sergio; Maggiolini, Marcello

2014-07-01

Nicotinic acid, also known as niacin, is the water soluble vitamin B3 used for decades for the treatment of dyslipidemic diseases. Its action is mainly mediated by the G protein-coupled receptor (GPR) 109A; however, certain regulatory effects on lipid levels occur in a GPR109A-independent manner. The amide form of nicotinic acid, named nicotinamide, acts as a vitamin although neither activates the GPR109A nor exhibits the pharmacological properties of nicotinic acid. In the present study, we demonstrate for the first time that nicotinic acid and nicotinamide bind to and activate the GPER-mediated signalling in breast cancer cells and cancer-associated fibroblasts (CAFs). In particular, we show that both molecules are able to promote the up-regulation of well established GPER target genes through the EGFR/ERK transduction pathway. As a biological counterpart, nicotinic acid and nicotinamide induce proliferative and migratory effects in breast cancer cells and CAFs in a GPER-dependent fashion. Moreover, nicotinic acid prevents the up-regulation of ICAM-1 triggered by the pro-inflammatory cytokine TNF-α and stimulates the formation of endothelial tubes through GPER in HUVECs. Together, our findings concerning the agonist activity for GPER displayed by both nicotinic acid and nicotinamide broaden the mechanisms involved in the biological action of these molecules and further support the potential of a ligand to induce different responses mediated in a promiscuous manner by distinct GPCRs. Copyright © 2014 Elsevier Inc. All rights reserved.

Mechanics of receptor-mediated endocytosis

NASA Astrophysics Data System (ADS)

Gao, Huajian; Shi, Wendong; Freund, Lambert B.

2005-07-01

Most viruses and bioparticles endocytosed by cells have characteristic sizes in the range of tens to hundreds of nanometers. The process of viruses entering and leaving animal cells is mediated by the binding interaction between ligand molecules on the viral capid and their receptor molecules on the cell membrane. How does the size of a bioparticle affect receptor-mediated endocytosis? Here, we study how a cell membrane containing diffusive mobile receptors wraps around a ligand-coated cylindrical or spherical particle. It is shown that particles in the size range of tens to hundreds of nanometers can enter or exit cells via wrapping even in the absence of clathrin or caveolin coats, and an optimal particles size exists for the smallest wrapping time. This model can also be extended to include the effect of clathrin coat. The results seem to show broad agreement with experimental observations. Author contributions: H.G. and L.B.F. designed research; H.G., W.S., and L.B.F. performed research; and H.G., W.S., and L.B.F. wrote the paper.Abbreviations: CNT, carbon nanotube; SWNT, single-walled nanotube.

Nuclear receptor coactivators function in estrogen receptor- and progestin receptor-dependent aspects of sexual behavior in female rats

PubMed Central

Molenda-Figueira, Heather A.; Williams, Casey A.; Griffin, Andreana L.; Rutledge, Eric M.; Blaustein, Jeffrey D.; Tetel, Marc J.

2008-01-01

The ovarian hormones, estradiol (E) and progesterone (P) facilitate the expression of sexual behavior in female rats. E and P mediate many of these behavioral effects by binding to their respective intracellular receptors in specific brain regions. Nuclear receptor coactivators, including Steroid Receptor Coactivator-1 (SRC-1) and CREB Binding Protein (CBP), dramatically enhance ligand-dependent steroid receptor transcriptional activity in vitro. Previously, our lab has shown that SRC-1 and CBP modulate estrogen receptor (ER)-mediated induction of progestin receptor (PR) gene expression in the ventromedial nucleus of the hypothalamus (VMN) and hormone-dependent sexual receptivity in female rats. Female sexual behaviors can be activated by high doses of E alone in ovariectomized rats, and thus are believed to be ER-dependent. However, the full repertoire of female sexual behavior, in particular, proceptive behaviors such as hopping, darting and ear wiggling, are considered to be PR-dependent. In the present experiments, the function of SRC-1 and CBP in distinct ER- (Exp. 1) and PR- (Exp. 2) dependent aspects of female sexual behavior was investigated. In Exp. 1, infusion of antisense oligodeoxynucleotides to SRC-1 and CBP mRNA into the VMN decreased lordosis intensity in rats treated with E alone, suggesting that these coactivators modulate ER-mediated female sexual behavior. In Exp. 2, antisense to SRC-1 and CBP mRNA around the time of P administration reduced PR-dependent ear wiggling and hopping and darting. Taken together, these data suggest that SRC-1 and CBP modulate ER and PR action in brain and influence distinct aspects of hormone-dependent sexual behaviors. These findings support our previous studies and provide further evidence that SRC-1 and CBP function together to regulate ovarian hormone action in behaviorally-relevant brain regions. PMID:16769066

Studies on the mechanism of functional cooperativity between progesterone and estrogen receptors.

PubMed

Bradshaw, M S; Tsai, S Y; Leng, X H; Dobson, A D; Conneely, O M; O'Malley, B W; Tsai, M J

1991-09-05

Steroid response elements (SREs) cooperate with many different cis-acting elements including NF-1 sites, CACCC boxes, and other SREs to induce target gene expression (Schule, R., Muller, M., Otsuka-Murakami, H., and Renkawitz, R. (1988) Nature 332, 87-90; Strahle, U., Schmid, W., and Schutz, G. (1988) EMBO J. 7, 3389-3395). Induction of gene expression can be additive or synergistic with respect to the level of activation by either transactivators. Two mechanisms have been proposed for how synergism occurs: 1) cooperative binding of transcriptional activators to DNA or 2) simultaneous interaction of individually bound activators with a common target protein. We have shown previously that cooperative binding of receptors is important for synergism between two progesterone response elements (PREs). Here we showed that an estrogen response element (ERE) and a PRE can also functionally cooperate and this synergism between an ERE and a PRE is not contributed by cooperative DNA binding. Furthermore, we have demonstrated that the activation domains of the progesterone receptor (PR) (C1Act) are required for synergism between two PREs and sufficient for confirming cooperative binding. However these two activation domains of PR are not sufficient for synergism between an ERE and a PRE. Additional regions within the NH2-terminal and COOH-terminal domains are also required for synergistic interaction between two heterologous SREs.

Estrogen regulation of gene expression in the teleost fish immune system.

PubMed

Burgos-Aceves, Mario Alberto; Cohen, Amit; Smith, Yoav; Faggio, Caterina

2016-11-01

Elucidating the mechanisms of estrogens-induced immunomodulation in teleost fish is of great importance due to the observed worldwide continuing decrease in pristine environments. However, little is know about the immunotoxicological consequences of exposure to these chemicals in fish, or of the mechanisms through which these effects are mediated. In this review, we summarize the results showing estrogens (natural or synthetic) acting through estrogen receptors and regulating specific target genes, also through microRNAs (miRNAs), leading to modulation of the immune functioning. The identification and characterization of miRNAs will provide new opportunities for functional genome research on teleost immune system and can also be useful when screening for novel molecule biomarkers for environmental pollution. Copyright © 2016 Elsevier Ltd. All rights reserved.

G-protein estrogen receptor as a regulator of low-density lipoprotein cholesterol metabolism: cellular and population genetic studies.

PubMed

Hussain, Yasin; Ding, Qingming; Connelly, Philip W; Brunt, J Howard; Ban, Matthew R; McIntyre, Adam D; Huff, Murray W; Gros, Robert; Hegele, Robert A; Feldman, Ross D

2015-01-01

Estrogen deficiency is linked with increased low-density lipoprotein (LDL) cholesterol. The hormone receptor mediating this effect is unknown. G-protein estrogen receptor (GPER) is a recently recognized G-protein-coupled receptor that is activated by estrogens. We recently identified a common hypofunctional missense variant of GPER, namely P16L. However, the role of GPER in LDL metabolism is unknown. Therefore, we examined the association of the P16L genotype with plasma LDL cholesterol level. Furthermore, we studied the role of GPER in regulating expression of the LDL receptor and proprotein convertase subtilisin kexin type 9. Our discovery cohort was a genetically isolated population of Northern European descent, and our validation cohort consisted of normal, healthy women aged 18 to 56 years from London, Ontario. In addition, we examined the effect of GPER on the regulation of proprotein convertase subtilisin kexin type 9 and LDL receptor expression by the treatment with the GPER agonist, G1. In the discovery cohort, GPER P16L genotype was associated with a significant increase in LDL cholesterol (mean±SEM): 3.18±0.05, 3.25±0.08, and 4.25±0.33 mmol/L, respectively, in subjects with CC (homozygous for P16), CT (heterozygotes), and TT (homozygous for L16) genotypes (P<0.05). In the validation cohort (n=339), the GPER P16L genotype was associated with a similar increase in LDL cholesterol: 2.17±0.05, 2.34±0.06, and 2.42±0.16 mmol/L, respectively, in subjects with CC, CT, and TT genotypes (P<0.05). In the human hepatic carcinoma cell line, the GPER agonist, G1, mediated a concentration-dependent increase in LDL receptor expression, blocked by either pretreatment with the GPER antagonist G15 or by shRNA-mediated GPER downregulation. G1 also mediated a GPER- and concentration-dependent decrease in proprotein convertase subtilisin kexin type 9 expression. GPER activation upregulates LDL receptor expression, probably at least, in part, via proprotein convertase

G-protein-coupled receptor 30 mediates the effects of estrogen on endothelial cell tube formation in vitro.

PubMed

Zhou, Liyuan; Chen, Hong; Mao, Xun; Qi, Hongbo; Baker, Philip N; Zhang, Hua

2017-06-01

The placenta is the exchange organ between the mother and the fetus. The inadequate function of this organ is associated with a number of pregnancy disorders. Hypoxia and oxidative stress during placental development may induce endothelial dysfunction, resulting in the reduction in the perfusion of the placenta. During pregnancy, the levels of estrogen are increased. Decreased estrogen levels have been reported in women with preeclampsia. However, whether estrogen is involved in placental angiogenesis remains unclear. In this study, we aimed to investigate the effects of estrogen on endothelial cell tube formation and to elucidate the underlying mechanisms. For this purpose, human umbilical vein endothelial cells (HUVECs) were cultured with 17‑β‑estradiol under conditions of hypoxia/reoxygenation (H/R). The total pipe length of the tube‑like structure on endothelial cells was measured. The expression levels of G‑protein‑coupled receptor 30 (GPR30) and endothelial nitric oxide synthase (eNOS) and Akt were also measured in the endothelial cells following treatment with 17‑β‑estradiol under H/R conditions by western blot analysis and immunostaining. We found that the total pipe length of the tube‑like structure on endothelial cells was significantly reduced. This reduction was reversed by treatment with 17‑β‑estradiol. The expression of GPR30 in endothelial cells was significantly increased following treatment with 17‑β‑estradiol under H/R conditions. Furthermore, the levels of eNOS and Akt in endothelial cells were also significantly increased following treatment with 17-β-estradiol under H/R conditions. The activation of eNOS was inhibited by wortmannin, an inhibitor of PI3K/Akt. Our data thus demonstrate that estrogen prevents the failure of endothelial cell tube formation induced by H/R. GPR30 plays an important role in these protective effects through the activation of eNOS and Akt in endothelial cells. Our data suggest that

Glyphosate induces growth of estrogen receptor alpha positive cholangiocarcinoma cells via non-genomic estrogen receptor/ERK1/2 signaling pathway.

PubMed

Sritana, Narongrit; Suriyo, Tawit; Kanitwithayanun, Jantamas; Songvasin, Benjaporn Homkajorn; Thiantanawat, Apinya; Satayavivad, Jutamaad

2018-06-08

Previous studies showed that glyphosate stimulates breast cancer cell growth via estrogen receptors. The present study investigated the effect of glyphosate on the estrogen signaling pathway involved in the induction of cholangiocarcinoma (CCA) cell growth. HuCCA-1, RMCCA-1 and MMNK-1 were chosen for comparison. The effects of glyphosate on cell growth, cell cycle and molecular signaling pathways were measured. The results showed that HuCCA-1 cells expressed estrogen receptor alpha (ERα), while ERα was not detected in RMCCA-1 and MMNK-1 cells. ERα was mostly expressed in cytoplasmic compartment of HuCCA-1 cells. Estradiol (E2) (10 -11 -10 -5  M) induced cell proliferation in HuCCA-1 but not in RMCCA-1 and MMNK-1 cells. Glyphosate at the same concentration range also induced HuCCA-1 cell proliferation. The S phase of the cell cycle, and protein levels of the cyclin family were significantly increased after treatment of glyphosate or E2. Both compounds also induced the expression of proliferative signaling-related proteins including ERα, VEGFR2, pERK, PI3K(p85), and PCNA. These effects of glyphosate and E2 were abolished by the ER antagonist, 4-hydroxytamoxifen and U0126, a MEK inhibitor. The data from this study indicate that glyphosate can induce cell growth in ERα positive CCA cells through non-genomic estrogen receptor/ERK1/2 signaling pathway. Copyright © 2018 Elsevier Ltd. All rights reserved.

Anti-inflammatory effects of tanshinone IIA on atherosclerostic vessels of ovariectomized ApoE mice are mediated by estrogen receptor activation and through the ERK signaling pathway.

PubMed

Liu, Xin; Guo, Chun-Yu; Ma, Xiao-Juan; Wu, Cai-Feng; Zhang, Ying; Sun, Ming-Yue; Pan, Yu-Ting; Yin, Hui-Jun

2015-01-01

Estrogen plays a protective role in atherosclerosis. Our preliminary work demonstrated that the active conformation of Tanshinone IIA(TanIIA) is similar to the 17β-estradiol and it can bind to the estrogen receptor. Here, we hypothesized that Tanshinone IIA might have anti-inflammatory and anti-oxidative effects in atherosclerosis, mediated through estrogen receptor activation. Subjects for this study were 120 apoE(-/-) female mice and 20 C57/BL female mice. The apoE(-/-) mice were ovariectomized (OVX) and the C57/BL mice were sham ovariectomized. The sham OVX mice were maintained on a normal diet (NOR) group. The OVX apoE(-/-) mice were fed a high fat diet and randomly divided into 6 groups: Model (MOD) group which was fed a high fat diet only, E2 group were given estrogen (E2) 0.13 mg/kg/d; E2+ICI group were given E2:0.13 mg/kg/d and ICI182780:65 mg/kg/m; TLD group (TanIIA low dose) were given TanIIA: 30 mg/kg/d; THD group (TanIIA high dose) were given TanIIA:60 mg/kg/d; and TLD+ICI group were given TanIIA 30 mg/kg/d and ICI182780 65 mg/kg/m. After three months of treatment, the aorta and the blood of the mice from each group was collected. The aorta were used for testing the lipid deposition by using hematoxylin and eosin(HE) and oil red O staining and for testing the expression of p-ERK1/2 by Western blot. The blood was used for testing the serum cholesterol, superoxide dismutase (SOD), methane dicarboxylic aldehyde (MDA), nuclear factor kappa (NF-κB), soluble intercellular cell adhesion molecule-1 (sICAM-1), activating protein-1 (AP-1), E-selectin and 17β-estradiol in serum. Tanshinone IIA significantly reduced the lipid deposition in aorta, decreased the levels of total cholesterol (TC), triglyceride (TG), low density lipoprotein (LDL), very low density lipoprotein (VLDL), MDA, NF-κB, sICAM-1, AP-1, and E-selectin in serum but increased the levels of high density lipoprotein (HDL) and SOD in serum. Tanshinone IIA also suppressed the expression of p-ERK1

GPR30 Activation Opposes Estrogen-Dependent Uterine Growth via Inhibition of Stromal ERK1/2 and Estrogen Receptor Alpha (ERα) Phosphorylation Signals

PubMed Central

Gao, Fei; Ma, Xinghong; Ostmann, Alicia B.

2011-01-01

Although estradiol-17β (E2)-regulated early and late phase uterine responses have been well defined, the molecular mechanisms linking the phases remain poorly understood. We have previously shown that E2-regulated early signals mediate cross talk with estrogen receptor (ER)-α to elicit uterine late growth responses. G protein-coupled receptor (GPR30) has been implicated in early nongenomic signaling mediated by E2, although its role in E2-dependent uterine biology is unclear. Using selective activation of GPR30 by G-1, we show here a new function of GPR30 in regulating early signaling events, including the inhibition of ERK1/2 and ERα (Ser118) phosphorylation signals and perturbation of growth regulation under the direction of E2 in the mouse uterus. We observed that GPR30 primarily localizes in the uterine epithelial cells, and its activation alters gene expression and mediates inhibition of ERK1/2 and ERα (Ser118) phosphorylation signals in the stromal compartment, suggesting a paracrine signaling is involved. Importantly, viral-driven manipulation of GPR30 or pharmacological inhibition of ERK1/2 activation effectively alters E2-dependent uterine growth responses. Overall, GPR30 is a negative regulator of ERα-dependent uterine growth in response to E2. Our work has uncovered a novel GPR30-regulated inhibitory event, which may be physiologically relevant in both normal and pathological situations to negatively balance ERα-dependent uterine growth regulatory functions induced by E2. PMID:21303939

The activation of G protein-coupled receptor 30 (GPR30) inhibits proliferation of estrogen receptor-negative breast cancer cells in vitro and in vivo.

PubMed

Wei, W; Chen, Z-J; Zhang, K-S; Yang, X-L; Wu, Y-M; Chen, X-H; Huang, H-B; Liu, H-L; Cai, S-H; Du, J; Wang, H-S

2014-10-02

There is an urgent clinical need for safe and effective treatment agents and therapy targets for estrogen receptor negative (ER-) breast cancer. G protein-coupled receptor 30 (GPR30), which mediates non-genomic signaling of estrogen to regulate cell growth, is highly expressed in ER--breast cancer cells. We here showed that activation of GPR30 by the receptor-specific agonist G-1 inhibited the growth of ER--breast cancer cells in vitro. Treatment of ER--breast cancer cells with G-1 resulted in G2/M-phase arrest, downregulation of G2-checkpoint regulator cyclin B, and induction of mitochondrial-related apoptosis. The G-1 treatment increased expression of p53 and its phosphorylation levels at Serine 15, promoted its nuclear translocation, and inhibited its ubiquitylation, which mediated the growth arrest effects on cell proliferation. Further, the G-1 induced sustained activation and nuclear translocation of ERK1/2, which was mediated by GPR30/epidermal growth factor receptor (EGFR) signals, also mediated its inhibition effects of G-1. With extensive use of siRNA-knockdown experiments and inhibitors, we found that upregulation of p21 by the cross-talk of GPR30/EGFR and p53 was also involved in G-1-induced cell growth arrest. In vivo experiments showed that G-1 treatment significantly suppressed the growth of SkBr3 xenograft tumors and increased the survival rate, associated with proliferation suppression and upregulation of p53, p21 while downregulation of cyclin B. The discovery of multiple signal pathways mediated the suppression effects of G-1 makes it a promising candidate drug and lays the foundation for future development of GPR30-based therapies for ER- breast cancer treatment.

Calmodulin Lobes Facilitate Dimerization and Activation of Estrogen Receptor-α*

PubMed Central

Li, Zhigang; Zhang, Yonghong; Hedman, Andrew C.; Ames, James B.

2017-01-01

Estrogen receptor α (ER-α) is a nuclear hormone receptor that controls selected genes, thereby regulating proliferation and differentiation of target tissues, such as breast. Gene expression controlled by ER-α is modulated by Ca2+ via calmodulin (CaM). Here we present the NMR structure of Ca2+-CaM bound to two molecules of ER-α (residues 287–305). The two lobes of CaM bind to the same site on two separate ER-α molecules (residues 292, 296, 299, 302, and 303), which explains why CaM binds two molecules of ER-α in a 1:2 complex and stabilizes ER-α dimerization. Exposed glutamate residues in CaM (Glu-11, Glu-14, Glu-84, and Glu-87) form salt bridges with key lysine residues in ER-α (Lys-299, Lys-302, and Lys-303), which is likely to prevent ubiquitination at these sites and inhibit degradation of ER-α. Transfection of cells with full-length CaM slightly increased the ability of estrogen to enhance transcriptional activation by ER-α of endogenous estrogen-responsive genes. By contrast, expression of either the N- or C-lobe of CaM abrogated estrogen-stimulated transcription of the estrogen responsive genes pS2 and progesterone receptor. These data suggest that CaM-induced dimerization of ER-α is required for estrogen-stimulated transcriptional activation by the receptor. In light of the critical role of ER-α in breast carcinoma, our data suggest that small molecules that selectively disrupt the interaction of ER-α with CaM may be useful in the therapy of breast carcinoma. PMID:28174300

Reversal of androgen inhibition of estrogen-activated sexual behavior by cholinergic agents.

PubMed

Dohanich, G P; Cada, D A

1989-12-01

Androgens have been found to inhibit lordosis activated by estrogen treatment of ovariectomized female rats. In the present experiments, dihydrotestosterone propionate (200 micrograms for 3 days) inhibited the incidence of lordosis in ovariectomized females treated with estradiol benzoate (1 microgram for 3 days). This inhibition of lordosis was reversed 15 min after bilateral intraventricular infusion of physostigmine (10 micrograms/cannula), an acetylcholinesterase inhibitor, or carbachol (0.5 microgram/cannula), a cholinergic receptor agonist. This reversal of inhibition appears to be mediated by cholinergic muscarinic receptors since pretreatment with scopolamine (4 mg/kg, ip), a muscarinic receptor blocker, prevented the reversal of androgen inhibition by physostigmine. These results indicate that androgens may inhibit estrogen-activated lordosis through interference with central cholinergic muscarinic mechanisms.

G protein-coupled estrogen receptor is required for the neuritogenic mechanism of 17β-estradiol in developing hippocampal neurons.

PubMed

Ruiz-Palmero, Isabel; Hernando, Maria; Garcia-Segura, Luis M; Arevalo, Maria-Angeles

2013-06-15

Estradiol promotes neuritogenesis in developing hippocampal neurons by a mechanism involving the upregulation of neurogenin 3, a Notch-regulated transcription factor. In this study we have explored whether G-protein coupled estrogen receptor 1 (GPER) participates in this hormonal action. GPER agonists (17β-estradiol, G1, ICI 182,780) increased neurogenin 3 expression and neuritogenesis in mouse primary hippocampal neurons and this effect was blocked by the GPER antagonist G15 and by a siRNA for GPER. In addition, GPER agonists increased Akt phosphorylation in ser473, which is indicative of the activation of phosphoinositide-3-kinase (PI3K). G15 or GPER silencing prevented the estrogenic induction of Akt phosphorylation. Furthermore, the PI3K inhibitor wortmannin prevented the effect of G1 and estradiol on neurogenin 3 expression and the effect of estradiol on neuritogenesis. These findings suggest that GPER participates in the control of hippocampal neuritogenesis by a mechanism involving the activation of PI3K signaling. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Investigations of new lead structures for the design of selective estrogen receptor modulators.

PubMed

Gust, R; Keilitz, R; Schmidt, K

2001-06-07

Heterocyclic derivatives of (R,S)/(S,R)-1-(2-chloro-4-hydroxyphenyl)-2-(2,6-dichloro-4-hydroxyphenyl)ethylenediamine (L1) were synthesized and tested for estrogen receptor binding. The selection of the heterocycles was based on theoretical consideration. (2R,3S)/(2S,3R)-2-(2-Chloro-4-hydroxyphenyl)-3-(2,6-dichloro-4-hydroxyphenyl)piperazine 2, (4R,5S)/(4S,5R)-4-(2-chloro-4-hydroxyphenyl)-5-(2,6-dichloro-4-hydroxyphenyl)-2-imidazoline 3, and 4-(2-chloro-4-hydroxyphenyl)-5-(2,6-dichloro-4-hydroxyphenyl)imidazole 4 possess a spatial structure with neighboring aromatic rings as is realized in hormonally active [1,2-diphenylethylenediamine]platinum(II) complexes. The 1,2-diphenylethane pharmacophor, however, cannot adapt an antiperiplanar conformation to interact with the estrogen receptor (ER) comparable to synthetic (e.g., diethylstilbestrol (DES)) or steroidal (e.g., estradiol (E2)) estrogens. Due to the different spatial structures, the heterocycles cause only a marginal displacement of E2 from its binding site (relative binding affinity (RBA) < 0.1%). Nevertheless, unequivocally ER mediated gene activation was verified on the MCF-7-2a cell line. Imidazoline 3 as the most active compound reached the maximum effect of E2 (100% activation) in a concentration of 5 x 10(-7) M, while piperazine 2 and imidazole 4 activate luciferase expression only in a small but significant amount of 20% and 27%, respectively. We therefore assigned these heterocyclic compounds to a second class of hormones (type-II-estrogens), which are attached at the ER at different amino acids than DES or E2 (type-I-estrogens).

Withaferin A Suppresses Estrogen Receptor-α Expression in Human Breast Cancer Cells

PubMed Central

Hahm, Eun-Ryeong; Lee, Joomin; Huang, Yi; Singh, Shivendra V.

2011-01-01

We have shown previously that withaferin A (WA), a promising anticancer constituent of Ayurvedic medicine plant Withania somnifera, inhibits growth of MCF-7 and MDA-MB-231 human breast cancer cells in culture and MDA-MB-231 xenografts in vivo by causing apoptosis. However, the mechanism of WA-induced apoptosis is not fully understood. The present study was designed to systematically determine the role of tumor suppressor p53 and estrogen receptor-α (ER-α) in proapoptotic response to WA using MCF-7, T47D, and ER-α overexpressing MDA-MB-231 cells as a model. WA treatment resulted in induction as well as increased Ser15 phosphorylation of p53 in MCF-7 cells, but RNA interference of this tumor suppressor gene conferred modest protection at best against WA-induced apoptosis. WA-mediated growth inhibition and apoptosis induction in MCF-7 cells were significantly attenuated in the presence of 17β-estradiol (E2). Exposure of MCF-7 cells to WA resulted in a marked decrease in protein levels of ER-α (but not ER-β) and ER-α regulated gene product pS2, and this effect was markedly attenuated in the presence of E2. WA-mediated down-regulation of ER-α protein expression correlated with a decrease in its nuclear level, suppression of its mRNA level, and inhibition of E2-dependent activation of ERE2e1b-luciferase reporter gene. Ectopic expression of ER-α in the MDA-MB-231 cell line conferred partial but statistically significant protection against WA-mediated apoptosis, but not G2/M phase cell cycle arrest. Collectively, these results indicate that WA functions as an anti-estrogen, and the proapoptotic effect of this promising natural product is partially attenuated by p53 knockdown and E2-ER-α. PMID:21432907

Genistein Promotes Proliferation of Human Cervical Cancer Cells Through Estrogen Receptor-Mediated PI3K/Akt-NF-κB Pathway

PubMed Central

Chen, Hai-Hong; Chen, Shu-Ping; Zheng, Qiu-Ling; Nie, Shao-Ping; Li, Wen-Juan; Hu, Xiao-Juan; Xie, Ming-Yong

2018-01-01

Phytoestrogens are polyphenol compounds which have similar structure to 17β-estradiol (E2), a kind of main estrogen in women. Thus, phytoestrogens may affect the reproductive and endocrine systems, leading to the development of estrogen-related cancers. The effect of genistein (Gen), one of the most studied phytoestrogens, on human cervical cancer cells (HeLa) was investigated in this study. It was found that Gen at concentrations of 0.001, 0.01, 0.1 and 1 µmol·L-1 promoted the proliferation of HeLa cells in a dose-dependent manner. Gen increased the portion of HeLa cells in S phase and decreased the portion of the cells in G1 phase. Besides, apoptosis rate of the cells was significantly lower when treated with Gen compared with the control group. It was also found that the expression of ERα, Akt or nuclear NF-κB p65 protein was activated by Gen. The correlation between these three proteins may be as following: ERα was the upstream, followed by Akt, and then nuclear NF-κB p65 protein. In addition, the downstream genes of activated nuclear NF-κB p65 were found to be associated with cell cycle and apoptosis of cancer cells. Our results suggested that Gen may stimulate cell proliferation partially through the estrogen receptor-mediated PI3K/Akt-NF-κB pathway and the further activation of the downstream genes of nuclear NF-κB p65. PMID:29344275

Activation of G protein-coupled estrogen receptor 1 (GPER-1) decreases fluid intake in female rats

PubMed Central

Santollo, Jessica; Daniels, Derek

2015-01-01

Estradiol (E2) decreases fluid intake in the female rat and recent studies from our lab demonstrate that the effect is at least in part mediated by membrane-associated estrogen receptors. Because multiple estrogen receptor subtypes can localize to the cell membrane, it is unclear which receptor(s) is generating the anti-dipsogenic effect of E2. The G protein-coupled estrogen receptor 1 (GPER-1) is a particularly interesting possibility because it has been shown to regulate blood pressure; many drinking-regulatory systems play overlapping roles in the control of blood pressure. Accordingly, we tested the hypothesis that activation of GPER-1 is sufficient to decrease fluid intake in female rats. In support of this hypothesis we found that treatment with the selective GPER-1 agonist G1 reduced AngII-stimulated fluid intake in OVX rats. Given the close association between food and fluid intakes in rats, and previous reports suggesting GPER-1 plays a role in energy homeostasis, we tested the hypothesis that the effect of GPER-1 on fluid intake was caused by a more direct effect on food intake. We found, however, that G1-treatment did not influence short-term or overnight food intake in OVX rats. Together these results reveal a novel effect of GPER-1 in the control of drinking behavior and provide an example of the divergence in the controls of fluid and food intakes in female rats. PMID:26093261

Activation of G protein-coupled estrogen receptor 1 (GPER-1) decreases fluid intake in female rats.

PubMed

Santollo, Jessica; Daniels, Derek

2015-07-01

Estradiol (E2) decreases fluid intake in the female rat and recent studies from our lab demonstrate that the effect is at least in part mediated by membrane-associated estrogen receptors. Because multiple estrogen receptor subtypes can localize to the cell membrane, it is unclear which receptor(s) is generating the anti-dipsogenic effect of E2. The G protein-coupled estrogen receptor 1 (GPER-1) is a particularly interesting possibility because it has been shown to regulate blood pressure; many drinking-regulatory systems play overlapping roles in the control of blood pressure. Accordingly, we tested the hypothesis that activation of GPER-1 is sufficient to decrease fluid intake in female rats. In support of this hypothesis we found that treatment with the selective GPER-1 agonist G1 reduced AngII-stimulated fluid intake in OVX rats. Given the close association between food and fluid intakes in rats, and previous reports suggesting GPER-1 plays a role in energy homeostasis, we tested the hypothesis that the effect of GPER-1 on fluid intake was caused by a more direct effect on food intake. We found, however, that G1-treatment did not influence short-term or overnight food intake in OVX rats. Together these results reveal a novel effect of GPER-1 in the control of drinking behavior and provide an example of the divergence in the controls of fluid and food intakes in female rats. Copyright © 2015 Elsevier Inc. All rights reserved.

Synergism between a half-site and an imperfect estrogen-responsive element, and cooperation with COUP-TFI are required for estrogen receptor (ER) to achieve a maximal estrogen-stimulation of rainbow trout ER gene.

PubMed

Petit, F G; Métivier, R; Valotaire, Y; Pakdel, F

1999-01-01

In all oviparous, liver represents one of the main E2-target tissues where estrogen receptor (ER) constitutes the key mediator of estrogen action. The rainbow trout estrogen receptor (rtER) gene expression is markedly up-regulated by estrogens and the sequences responsible for this autoregulation have been located in a 0.2 kb upstream transcription start site within - 40/- 248 enhancer region. Absence of interference with steroid hormone receptors and tissue-specific factors and a conserved basal transcriptional machinery between yeast and higher eukaryotes, make yeast a simple assay system that will enable determination of important cis-acting regulatory sequences within rtER gene promoter and identification of transcription factors implicated in the regulation of this gene. Deletion analysis allowed to show a synergistic effect between an imperfect estrogen-responsive element (ERE) and a consensus half-ERE to achieve a high hormone-dependent transcriptional activation of the rtER gene promoter in the presence of stably expressed rtER. As in mammalian cells, here we observed a positive regulation of the rtER gene promoter by the chicken ovalbumin upstream promoter-transcription factor I (COUP-TFI) through enhancing autoregulation. Using a point mutation COUP-TFI mutant unable to bind DNA demonstrates that enhancement of rtER gene autoregulation requires the interaction of COUP-TFI to the DNA. Moreover, this enhancement of transcriptional activation by COUP-TFI requires specifically the AF-1 transactivation function of ER and can be observed in the presence of E2 or 4-hydroxytamoxifen but not ICI 164384. Thus, this paper describes the reconstitution of a hormone-responsive transcription unit in yeast in which the regulation of rtER gene promoter could be enhanced by the participation of cis-elements and/or trans-acting factors, such as ER itself or COUP-TF.

Protective effects of estrogen against vascular calcification via estrogen receptor α-dependent growth arrest-specific gene 6 transactivation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nanao-Hamai, Michiko; Son, Bo-Kyung; Institute of Gerontology, The University of Tokyo, Tokyo

Vascular calcification is one of the major complications of cardiovascular disease and is an independent risk factor for myocardial infarction and cardiac death. Postmenopausal women have a higher prevalence of vascular calcification compared with premenopausal women, suggesting protective effects of estrogen (E2). However, the underlying mechanisms of its beneficial effects remain unclear. In the present study, we examined the inhibitory effects of E2 on vascular smooth muscle cell (VSMC) calcification, and found that growth arrest-specific gene 6 (Gas6), a crucial molecule in vascular calcification, is transactivated by estrogen receptor α (ERα) in response to E2. In human aortic smooth musclemore » cells, physiological levels of E2 inhibited inorganic phosphate (Pi)-induced calcification in a concentration-dependent manner. This inhibitory effect was significantly abolished by MPP, an ERα-selective antagonist, and ERα siRNA, but not by PHTPP, an ERβ-selective antagonist, and ERβ siRNA, implicating an ERα-dependent action. Apoptosis, an essential process for Pi-induced VSMC calcification, was inhibited by E2 in a concentration-dependent manner and further, MPP abolished this inhibition. Mechanistically, E2 restored the inhibited expression of Gas6 and phospho-Akt in Pi-induced apoptosis through ERα. Furthermore, E2 significantly activated Gas6 transcription, and MPP abrogated this E2-dependent Gas6 transactivation. E2-BSA failed to activate Gas6 transcription and to inhibit Ca deposition in VSMC, suggesting beneficial actions of genomic signaling by E2/nuclear ERα. Taken together, these results indicate that E2 exerts inhibitory effects on VSMC apoptosis and calcification through ERα-mediated Gas6 transactivation. These findings indicate a potential therapeutic strategy for the prevention of vascular calcification, especially in postmenopausal women. - Highlights: • E2 inhibits Pi-induced calcification in vascular smooth muscles cells. • E2

The polymorphism of estrogen receptor α is important for metabolic consequences associated with menopause.

PubMed

Pinkas, Jarosław; Gujski, Mariusz; Wierzbińska-Stępniak, Anna; Owoc, Alfred; Bojar, Iwona

2016-01-01

Menopause is associated with multiple health and metabolic consequences resulting from the decrease in estrogens level. Women at postmenopausal age are burdened with a higher risk of cardiovascular diseases, and the main cause of mortality in this group is ischemic heart disease. Estrogen deficiency is related, among other things, with frequent occurrence of dislipidemia, cessation of the beneficial effect of estrogens on the vascular wall, increase in body weight characterized by unfavourable redistribution of fatty tissue, with an increased amount of visceral fat and reduction of so-called non-fatty body mass. Estrogens exert an effect on metabolism, mainly through the genomic mechanism. The presence of α and β estrogen receptors was found in many tissues and organs. Recently, attention was paid to the fact that the effect of estrogens action on tissues and organs may depend not only on distribution, but also on their polymorphic types. The article presents the latest approach to the problem of metabolic consequences resulting from menopause, according to the possessed α estrogen receptor polymorphism (ERα).Genes encoding for ERα have many polymorphic variants, the most important of which from the clinical aspect are two single nucleotide polymorphisms (SNPs) - Xba1 and PvuII. The review of literature indicates that ERα polymorphisms are of great importance with respect to the effect of estrogens on the functioning of the body of a woman after menopause, and may imply the development of many pathological states, including the prevention or development of metabolic disorders. Identifying ERα polymorphisms may be useful in case of estrogen therapy for menopausal women who may benefit from it.

Recurrence of Cervical Cancer in Mice after Selective Estrogen Receptor Modulator Therapy

PubMed Central

Spurgeon, Megan E.; Chung, Sang-Hyuk; Lambert, Paul F.

2015-01-01

Estrogen and its nuclear receptor, estrogen receptor α, are necessary cofactors in the initiation and multistage progression of carcinogenesis in the K14E6/E7 transgenic mouse model of human papillomavirus–associated cervical cancer. Recently, our laboratory reported that raloxifene, a selective estrogen receptor modulator, promoted regression of high-grade dysplasia and cancer that arose in the cervix of K14E6/E7 transgenic mice treated long-term with estrogen. Herein, we evaluated the recurrence of cervical cancer after raloxifene therapy in our preclinical model of human papillomavirus–associated cervical carcinogenesis. We observed recurrence of cervical cancer in mice re-exposed to estrogen after raloxifene treatment, despite evidence suggesting the antagonistic effects of raloxifene persisted in the reproductive tract after treatment had ceased. We also observed recurrence of neoplastic disease in mice that were not retreated with exogenous estrogen, although the severity of disease was less. Recurrent neoplastic disease and cancers retained functional estrogen receptor α and responded to retreatment with raloxifene. Moreover, continuous treatment of mice with raloxifene prevented the emergence of recurrent disease seen in mice in which raloxifene was discontinued. These data suggest that cervical cancer cells are not completely eradicated by raloxifene and rapidly expand if raloxifene treatment is ceased. These findings indicate that a prolonged treatment period with raloxifene might be required to prevent recurrence of neoplastic disease and lower reproductive tract cancers. PMID:24418098

G protein-coupled estrogen receptor and estrogen receptor ligands regulate colonic motility and visceral pain.

PubMed

Zielińska, M; Fichna, J; Bashashati, M; Habibi, S; Sibaev, A; Timmermans, J-P; Storr, M

2017-07-01

Diarrhea-predominant irritable bowel syndrome (IBS-D) is a functional gastrointestinal (GI) disorder, which occurs more frequently in women than men. The aim of our study was to determine the role of activation of classical estrogen receptors (ER) and novel membrane receptor, G protein-coupled estrogen receptor (GPER) in human and mouse tissue and to assess the possible cross talk between these receptors in the GI tract. Immunohistochemistry was used to determine the expression of GPER in human and mouse intestines. The effect of G-1, a GPER selective agonist, and estradiol, a non-selective ER agonist, on muscle contractility was characterized in isolated preparations of the human and mouse colon. To characterize the effect of G-1 and estradiol in vivo, colonic bead expulsion test was performed. G-1 and estradiol activity on the visceral pain signaling was assessed in the mustard oil-induced abdominal pain model. GPER is expressed in the human colon and in the mouse colon and ileum. G-1 and estradiol inhibited muscle contractility in vitro in human and mouse colon. G-1 or estradiol administered intravenously at the dose of 20 mg/kg significantly prolonged the time to bead expulsion in females. Moreover, G-1 prolonged the time to bead expulsion and inhibited GI hypermotility in both genders. The injection of G-1 or estradiol resulted in a significant reduction in the number of pain-induced behaviors in mice. GPER and ER receptors are involved in the regulation of GI motility and visceral pain. Both may thus constitute an important pharmacological target in the IBS-D therapy. © 2017 John Wiley & Sons Ltd.

Estrogen Biology: New Insights into GPER Function and Clinical Opportunities

PubMed Central

Prossnitz, Eric R.; Barton, Matthias

2014-01-01

Estrogens play an important role in the regulation of normal physiology, aging and many disease states. Although the nuclear estrogen receptors have classically been described to function as ligand-activated transcription factors mediating genomic effects in hormonally regulated tissues, more recent studies reveal that estrogens also mediate rapid signaling events traditionally associated with G protein-coupled receptors. The G protein-coupled estrogen receptor GPER (formerly GPR30) has now become recognized as a major mediator of estrogen’s rapid cellular effects throughout the body. With the discovery of selective synthetic ligands for GPER, both agonists and antagonists, as well as the use of GPER knockout mice, significant advances have been made in our understanding of GPER function at the cellular, tissue and organismal levels. In many instances, the protective/beneficial effects of estrogen are mimicked by selective GPER agonism and are absent or reduced in GPER knockout mice, suggesting an essential or at least parallel role for GPER in the actions of estrogen. In this review, we will discuss recent advances and our current understanding of the role of GPER and certain drugs such as SERMs and SERDs in physiology and disease. We will also highlight novel opportunities for clinical development towards GPER-targeted therapeutics, for molecular imaging, as well as for theranostic approaches and personalized medicine. PMID:24530924

Antiestrogenic activity of flavnoid phytochemicals mediated via c-Jun N-terminal protein kinase pathway. Cell-type specific regulation of estrogen receptor alpha

USDA-ARS?s Scientific Manuscript database

Flavonoid phytochemicals act as both agonists and antagonists of the human estrogen receptors (ERs). While a number of these compounds act by directly binding to the ER, certain phytochemicals, such as the flavonoid compounds chalcone and flavone, elicit antagonistic effects on estrogen signaling in...

Hormone Binding to Recombinant Estrogen Receptors from Human, Alligator, Quail, Salamander, and Fathead Minnow

EPA Science Inventory

In this work, a 96-well plate estrogen receptor binding assay was developed to facilitate the direct comparison of chemical binding to full-length recombinant estrogen receptors across vertebrate classes. Receptors were generated in a baculovirus expression system. This approach ...

Identification of Breast Cancer Inhibitors Specific for G Protein-Coupled Estrogen Receptor (GPER)-Expressing Cells.

PubMed

Aiello, Francesca; Carullo, Gabriele; Giordano, Francesca; Spina, Elena; Nigro, Alessandra; Garofalo, Antonio; Tassini, Sabrina; Costantino, Gabriele; Vincetti, Paolo; Bruno, Agostino; Radi, Marco

2017-08-22

Together with estrogen receptors ERα and ERβ, the G protein-coupled estrogen receptor (GPER) mediates important pathophysiological signaling pathways induced by estrogens and is currently regarded as a promising target for ER-negative (ER-) and triple-negative (TN) breast cancer. Only a few selective GPER modulators have been reported to date, and their use in cancer cell lines has often led to contradictory results. Herein we report the application of virtual screening and cell-based studies for the identification of new chemical scaffolds with a specific antiproliferative effect against GPER-expressing breast cancer cell lines. Out of the four different scaffolds identified, 8-chloro-4-(4-chlorophenyl)pyrrolo[1,2-a]quinoxaline 14 c was found to be the most promising compound able to induce: 1) antiproliferative activity in GPER-expressing cell lines (MCF7 and SKBR3), similarly to G15; 2) no effect on cells that do not express GPER (HEK293); 3) a decrease in cyclin D1 expression; and 4) a sustained induction of cell-cycle negative regulators p53 and p21. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

The G-protein coupled estrogen receptor, GPER: The inside and inside-out story.

PubMed

Gaudet, H M; Cheng, S B; Christensen, E M; Filardo, E J

2015-12-15

GPER possesses structural and functional characteristics shared by members of the G-protein-coupled receptor (GPCR) superfamily, the largest class of plasma membrane receptors. This newly appreciated estrogen receptor is localized predominately within intracellular membranes in most, but not all, cell types and its surface expression is modulated by steroid hormones and during tissue injury. An intracellular staining pattern is not unique among GPCRs, which employ a diverse array of molecular mechanisms that restrict cell surface expression and effectively regulating receptor binding and activation. The finding that GPER displays an intracellular predisposition has created some confusion as the estrogen-inducible transcription factors, ERα and ERβ, also reside intracellularly, and has led to complex suggestions of receptor interaction. GPER undergoes constitutive retrograde trafficking from the plasma membrane to the endoplasmic reticulum and recent studies indicate its interaction with PDZ binding proteins that sort transmembrane receptors to synaptosomes and endosomes. Genetic targeting and selective ligand approaches as well as cell models that express GPER in the absence of ERs clearly supports GPER as a bonafide "stand alone" receptor. Here, the molecular details that regulate GPER action, its cell biological activities and its implicated roles in physiological and pathological processes are reviewed. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Akt mediates 17beta-estradiol and/or estrogen receptor-alpha inhibition of LPS-induced tumor necresis factor-alpha expression and myocardial cell apoptosis by suppressing the JNK1/2-NFkappaB pathway.

PubMed

Liu, Chung-Jung; Lo, Jeng-Fan; Kuo, Chia-Hua; Chu, Chun-Hsien; Chen, Li-Ming; Tsai, Fuu-Jen; Tsai, Chang-Hai; Tzang, Bor-Show; Kuo, Wei-Wen; Huang, Chih-Yang

2009-09-01

Evidence shows that women have lower tumour necrosis factor-alpha (TNF-alpha) levels and lower incidences of heart dysfunction and sepsis-related morbidity and mortality. To identify the cardioprotective effects and precise cellular/molecular mechanisms behind estrogen and estrogen receptors (ERs), we investigated the effects of 17beta-estradiol (E(2)) and estrogen receptor alpha (ERalpha) on LPS-induced apoptosis by analyzing the activation of survival and death signalling pathways in doxycycline (Dox)-inducible Tet-On/ERalpha H9c2 myocardial cells and ERalpha-transfected primary cardiomyocytes overexpressing ERalpha. We found that LPS challenge activated JNK1/2, and then induced IkappaB degradation, NFkappaB activation, TNF-alpha up-regulation and subsequent myocardial apoptotic responses. In addition, treatments involving E(2), membrane-impermeable BSA-E(2) and/or Dox, which induces ERalpha overexpression, significantly inhibited LPS-induced apoptosis by suppressing LPS-up-regulated JNK1/2 activity, IkappaB degradation, NFkappaB activation and pro-apoptotic proteins (e.g. TNF-alpha, active caspases-8, t-Bid, Bax, released cytochrome c, active caspase-9, active caspase-3) in myocardial cells. However, the cardioprotective properties of E(2), BSA-E(2) and ERalpha overexpression to inhibit LPS-induced apoptosis and promote cell survival were attenuated by applying LY294002 (PI3K inhibitor) and PI3K siRNA. These findings suggest that E(2), BSA-E(2) and ERalpha expression exert their cardioprotective effects by inhibiting JNK1/2-mediated LPS-induced TNF-alpha expression and cardiomyocyte apoptosis through activation of Akt.

Estrogen receptor (ESR1) mutation in bone metastases from breast cancer.

PubMed

Bartels, Stephan; Christgen, Matthias; Luft, Angelina; Persing, Sascha; Jödecke, Kai; Lehmann, Ulrich; Kreipe, Hans

2018-01-01

Activating mutations of estrogen receptor α gene (ESR1) in breast cancer can cause endocrine resistance of metastatic tumor cells. The skeleton belongs to the metastatic sides frequently affected by breast cancer. The prevalence of ESR1 mutation in bone metastasis and the corresponding phenotype are not known. In this study bone metastases from breast cancer (n=231) were analyzed for ESR1 mutation. In 27 patients (12%) (median age 73 years, range: 55-82 years) activating mutations of ESR1 were detected. The most frequent mutation was p.D538G (53%), no mutations in exon 4 (K303) or 7 (S463) were found. Lobular breast cancer was present in 52% of mutated cases (n=14) and in 49% of all samples (n=231), respectively. Mutated cancers constantly displayed strong estrogen receptor expression. Progesterone receptor was positive in 78% of the mutated cases (n=21). From 194 estrogen receptor-positive samples, 14% had ESR1 mutated. Except for one mutated case, no concurrent HER2 overexpression was noted. Metastatic breast cancer with activating mutations of ESR1 had a higher Ki67 labeling index than primary luminal cancers (median 30%, ranging from 5 to 60% with 85% of cases revealing ≥20% Ki67-positive cells). From those patients from whom information on endocrine therapy was available (n=7), two had received tamoxifen only, 4 tamoxifen followed by aromatase inhibitors and one patient had been treated with aromatase inhibitors only. We conclude that ESR1 mutation is associated with estrogen receptor expression and high proliferative activity and affects about 14% of estrogen receptor-positive bone metastases from breast cancer.

Nuclear and Membrane Actions of Estrogen Receptor Alpha: Contribution to the Regulation of Energy and Glucose Homeostasis.

PubMed

Guillaume, Maeva; Montagner, Alexandra; Fontaine, Coralie; Lenfant, Françoise; Arnal, Jean-François; Gourdy, Pierre

2017-01-01

Estrogen receptor alpha (ERα) has been demonstrated to play a key role in reproduction but also to exert numerous functions in nonreproductive tissues. Accordingly, ERα is now recognized as a key regulator of energy homeostasis and glucose metabolism and mediates the protective effects of estrogens against obesity and type 2 diabetes. This chapter attempts to summarize our current understanding of the mechanisms of ERα activation and their involvement in the modulation of energy balance and glucose metabolism. We first focus on the experimental studies that constitute the basis of the understanding of ERα as a nuclear receptor and more specifically on the key roles played by its two activation functions (AFs). We depict the consequences of the selective inactivation of these AFs in mouse models, which further underline the prominent role of nuclear ERα in the prevention of obesity and diabetes, as on the reproductive tract and the vascular system. Besides these nuclear actions, a fraction of ERα is associated with the plasma membrane and activates nonnuclear signaling from this site. Such rapid effects, called membrane-initiated steroid signals (MISS), have been characterized in a variety of cell lines and in particular in endothelial cells. The development of selective pharmacological tools that specifically activate MISS as well as the generation of mice expressing an ERα protein impeded for membrane localization has just begun to unravel the physiological role of MISS in vivo and their contribution to ERα-mediated metabolic protection. Finally, we discuss novel perspectives for the design of tissue-selective ER modulators.

Estrogen Inhibits Dlk1/FA1 Production: A Potential Mechanism for Estrogen Effects on Bone Turnover

PubMed Central

Abdallah, B. M.; Bay-Jensen, A.; Srinivasan, B.; Tabassi, N. C.; Garnero, P.; Delaissé, J.; Khosla, S.; Kassem, M.

2011-01-01

We have recently identified Dlk1/FA1 (Delta-like 1/FA1) as a novel regulator of bone mass that functions to mediate bone loss, under estrogen deficiency, in mice. In this report, we investigated the effects of estrogen (E)-deficiency and E replacement on serum (s) levels of Dlk1/FA1 (s-Dlk1FA1) and its correlation with bone turnover markers. s-Dlk1/FA1 and bone turnover markers (s-CTx and s-osteocalcin), were measured in two cohorts: a group of pre- and postmenopausal women (n=100) and a group of postmenopausal women, where half had received estrogen replacement therapy (ERT) (n=166). s-Dlk1/FA1, and s-CTX were elevated in postmenopausal E-deficient compared to premenopausal E-replete women (both; P<0.001). s-Dlk1/FA1 was correlated with s-CTX (r=0.30, P<0.01). ERT, in postmenopausal women, decreased s-Dlk1/FA1, as well as s-CTX and s-osteoclacin (all; P<0.0001). Changes in s-Dlk1 were significantly correlated with those observed in s-CTx (r=0.18, P<0.05) and s-osteocalcin (r=0.28, P<0.001). In conclusion, s-Dlk1/FA1 is influenced by E-deficiency and is correlated with bone turnover. Increased levels of s-Dlk1/FA1 in post-menopausal women may be a mechanism mediating the effects estrogen deficiency on bone turnover. PMID:21681814

COMPARATIVE DOCKING STUDIES OF THE BINDING OF POLYCYCLIC AROMATIC HYDROCARBONS TO THE ESTROGEN RECEPTOR

EPA Science Inventory

The interactions of several PAHs, and some of their possible metabolites, with the ligand binding domain of the estrogen receptor have been examined using molecular docking and quantum mechanical methods. The geometries of the PAHs were optimized at the Hartree-Fock level and the...

The estrogen-related receptors (ERRs): potential targets against bone loss.

PubMed

Zhang, Ling; Wong, Jiemin; Vanacker, Jean-Marc

2016-10-01

Bone loss and the resulting skeletal fragility is induced by several pathological or natural conditions, the most prominent of which being aging as well as the decreased levels of circulating estrogens in post-menopause females. To date, most treatments against bone loss aim at preventing excess bone resorption. We here summarize data indicating that the estrogen-related receptors (ERRs) α and γ prevent bone formation. Inhibiting these receptors may thus constitute an anabolic approach by increasing bone formation.

Thyroid hormone regulates vitellogenin by inducing estrogen receptor alpha in the goldfish liver.

PubMed

Nelson, Erik R; Habibi, Hamid R

2016-11-15

Vitellogenin (Vtg) is an egg-yolk precursor protein that is synthesized in the liver of oviparous species and taken up from the circulation by the ovary. It is well known that Vtg is induced by circulating estrogens. However, other endocrine factors that regulate the expression of Vtg are less well characterized; factors that might play significant roles, especially in seasonal spawners such as the goldfish which require increased quantities of Vtg for the development of hundreds of follicles. In this regard, thyroid hormones have been shown to cycle with the reproductive season. Therefore, we hypothesized that the thyroid hormones might influence the synthesis of Vtg. Treatment of female goldfish with triiodothyronine (T3) resulted in increased Vtg, an observation that was absent in males. Furthermore, T3 failed to induce Vtg in cultured hepatocytes of either sex. Interestingly however, T3 consistently up-regulated the expression of the estrogen receptor alpha (ERα). The T3 mediated upregulation of ERα requires the presence of both thyroid receptor (TR) α-1 and TRβ. When goldfish or cultured hepatocytes were treated with T3 followed by estradiol, there was a synergistic increase in Vtg, a response which is dependent on the presence of ERα. Therefore, by upregulating ERα, T3 serves to prime the liver to subsequent stimuli from estradiol. This cross-talk likely reveals an important physiologic mechanism by which thyroid hormones, whose circulating levels are high during early gonadal recrudescence, facilitate the production of large amounts of Vtg required for egg development. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Novel Aspects Concerning the Functional Cross-Talk between the Insulin/IGF-I System and Estrogen Signaling in Cancer Cells

PubMed Central

De Marco, Paola; Cirillo, Francesca; Vivacqua, Adele; Malaguarnera, Roberta; Belfiore, Antonino; Maggiolini, Marcello

2015-01-01

The insulin/IGF system plays an important role in cancer progression. Accordingly, elevated levels of circulating insulin have been associated with an increased cancer risk as well as with aggressive and metastatic cancer phenotypes. Numerous studies have documented that estrogens cooperate with the insulin/IGF system in multiple pathophysiological conditions. The biological responses to estrogens are mainly mediated by the estrogen receptors (ER)α and ERβ, which act as transcription factors; however, several studies have recently demonstrated that a member of the G protein-coupled receptors, named GPR30/G-protein estrogen receptor (GPER), is also involved in the estrogen signaling in normal and malignant cells as well as in cancer-associated fibroblasts (CAFs). In this regard, novel mechanisms linking the action of estrogens through GPER with the insulin/IGF system have been recently demonstrated. This review recapitulates the relevant aspects of this functional cross-talk between the insulin/IGF and the estrogenic GPER transduction pathways, which occurs in various cell types and may account for cancer progression. PMID:25798130

Novel Aspects Concerning the Functional Cross-Talk between the Insulin/IGF-I System and Estrogen Signaling in Cancer Cells.

PubMed

De Marco, Paola; Cirillo, Francesca; Vivacqua, Adele; Malaguarnera, Roberta; Belfiore, Antonino; Maggiolini, Marcello

2015-01-01

The insulin/IGF system plays an important role in cancer progression. Accordingly, elevated levels of circulating insulin have been associated with an increased cancer risk as well as with aggressive and metastatic cancer phenotypes. Numerous studies have documented that estrogens cooperate with the insulin/IGF system in multiple pathophysiological conditions. The biological responses to estrogens are mainly mediated by the estrogen receptors (ER)α and ERβ, which act as transcription factors; however, several studies have recently demonstrated that a member of the G protein-coupled receptors, named GPR30/G-protein estrogen receptor (GPER), is also involved in the estrogen signaling in normal and malignant cells as well as in cancer-associated fibroblasts (CAFs). In this regard, novel mechanisms linking the action of estrogens through GPER with the insulin/IGF system have been recently demonstrated. This review recapitulates the relevant aspects of this functional cross-talk between the insulin/IGF and the estrogenic GPER transduction pathways, which occurs in various cell types and may account for cancer progression.

Design and Synthesis of Selective Estrogen Receptor beta Agonists and Their Pharmacology

NASA Astrophysics Data System (ADS)

Perera, K. L. Iresha Sampathi

Estrogens (17beta-estradiol, E2) have garnered considerable attention in influencing cognitive process in relation to phases of the menstrual cycle, aging and menopausal symptoms. However, hormone replacement therapy can have deleterious effects leading to breast and endometrial cancer, predominantly mediated by estrogen receptor-alpha (ERalpha) the major isoform present in the mammary gland and uterus. Further evidence supports a dominant role of estrogen receptor-beta (ERbeta) for improved cognitive effects such as enhanced hippocampal signaling and memory consolidation via estrogen activated signaling cascades. Creation of the ERbeta selective ligands is challenging due to high structural similarity of both receptors. Thus far, several ERbeta selective agonists have been developed, however, none of these have made it to clinical use due to their lower selectivity or considerable side effects. The research in this dissertation involved the design of non-steroidal ERbeta selective agonists for hippocampal memory consolidation. The step-wise process to achieve the ultimate goal of this research includes: (1) design and synthesis of (4-hydroxyphenyl)cyclohexyl or cycloheptyl derivatives, (2) in vitro biological evaluation of synthesized compounds to identify highly potent and selective candidates, and (3) in vivo biological evaluation of selected candidates for hippocampal memory consolidation. Several (4-hydroxyphenyl)cyclohexyl or cycloheptyl derivatives were synthesized having structural alterations on both aromatic and cyclohexyl/heptyl ring scaffolds. ERbeta agonist potency was initially evaluated in TR-FRET ERbeta ligand binding assay and compounds having high potency were re-evaluated in functional cell based assays for potency and ERbeta vs. ERalpha selectivity. Two compounds from each series, ISP 163-PK4 and ISP 358-2 were identified as most selective ERbeta agonists. Both compounds revealed high metabolic stability, solubility and no cross reactivity

Knockdown of estrogen receptor-α induces autophagy and inhibits antiestrogen-mediated unfolded protein response activation, promoting ROS-induced breast cancer cell death

PubMed Central

Cook, Katherine L.; Clarke, Pamela A. G.; Parmar, Jignesh; Hu, Rong; Schwartz-Roberts, Jessica L.; Abu-Asab, Mones; Wärri, Anni; Baumann, William T.; Clarke, Robert

2014-01-01

Approximately 70% of all newly diagnosed breast cancers express estrogen receptor (ER)-α. Although inhibiting ER action using targeted therapies such as fulvestrant (ICI) is often effective, later emergence of antiestrogen resistance limits clinical use. We used antiestrogen-sensitive and -resistant cells to determine the effect of antiestrogens/ERα on regulating autophagy and unfolded protein response (UPR) signaling. Knockdown of ERα significantly increased the sensitivity of LCC1 cells (sensitive) and also resensitized LCC9 cells (resistant) to antiestrogen drugs. Interestingly, ERα knockdown, but not ICI, reduced nuclear factor (erythroid-derived 2)-like (NRF)-2 (UPR-induced antioxidant protein) and increased cytosolic kelch-like ECH-associated protein (KEAP)-1 (NRF2 inhibitor), consistent with the observed increase in ROS production. Furthermore, autophagy induction by antiestrogens was prosurvival but did not prevent ERα knockdown–mediated death. We built a novel mathematical model to elucidate the interactions among UPR, autophagy, ER signaling, and ROS regulation of breast cancer cell survival. The experimentally validated mathematical model explains the counterintuitive result that knocking down the main target of ICI (ERα) increased the effectiveness of ICI. Specifically, the model indicated that ERα is no longer present in excess and that the effect on proliferation from further reductions in its level by ICI cannot be compensated for by increased autophagy. The stimulation of signaling that can confer resistance suggests that combining autophagy or UPR inhibitors with antiestrogens would reduce the development of resistance in some breast cancers.—Cook, K. L., Clarke, P. A. G., Parmar, J., Hu, R., Schwartz-Roberts, J. L., Abu-Asab, M., Wärri, A., Baumann, W. T., Clarke, R. Knockdown of estrogen receptor-α induces autophagy and inhibits antiestrogen-mediated unfolded protein response activation, promoting ROS-induced breast cancer cell death

Receptor-mediated cell mechanosensing

PubMed Central

Chen, Yunfeng; Ju, Lining; Rushdi, Muaz; Ge, Chenghao; Zhu, Cheng

2017-01-01

Mechanosensing describes the ability of a cell to sense mechanical cues of its microenvironment, including not only all components of force, stress, and strain but also substrate rigidity, topology, and adhesiveness. This ability is crucial for the cell to respond to the surrounding mechanical cues and adapt to the changing environment. Examples of responses and adaptation include (de)activation, proliferation/apoptosis, and (de)differentiation. Receptor-mediated cell mechanosensing is a multistep process that is initiated by binding of cell surface receptors to their ligands on the extracellular matrix or the surface of adjacent cells. Mechanical cues are presented by the ligand and received by the receptor at the binding interface; but their transmission over space and time and their conversion into biochemical signals may involve other domains and additional molecules. In this review, a four-step model is described for the receptor-mediated cell mechanosensing process. Platelet glycoprotein Ib, T-cell receptor, and integrins are used as examples to illustrate the key concepts and players in this process. PMID:28954860

Divergent effects of estradiol and the estrogen receptor-alpha agonist PPT on eating and activation of PVN CRH neurons in ovariectomized rats and mice.

PubMed

Thammacharoen, Sumpun; Geary, Nori; Lutz, Thomas A; Ogawa, Sonoko; Asarian, Lori

2009-05-01

Eating is modulated by estradiol in females of many species and in women. To further investigate the estrogen receptor mechanism mediating this effect, ovariectomized rats and mice were treated with estradiol benzoate or the estrogen receptor-alpha (ER-alpha)-selective agonist PPT. PPT inhibited eating in rats much more rapidly than estradiol (approximately 2-6 h versus >24 h). In contrast, the latencies to vaginal estrus after PPT and estradiol were similar (>24 h). PPT also inhibited eating within a few hours in wild-type mice, but failed to inhibit eating in transgenic mice deficient in ER-alpha (ERalphaKO mice). PPT, but not estradiol, induced the expression of c-Fos in corticotrophin-releasing hormone (CRH)-expressing cells of the paraventricular nucleus (PVN) of the hypothalamus within 90-180 min in rats. Both PPT and estradiol reduced c-Fos expression in an ER-alpha-containing area of the nucleus of the solitary tract. The anomalously rapid eating-inhibitory effect of PPT suggests that PPT's neuropharmacological effect differs from estradiol's, perhaps because PPT differentially activates membrane versus nuclear ER-alpha or because PPT activates non-ER-alpha membrane estrogen receptors in addition to ER-alpha. The failure of PPT to inhibit eating in ERalphaKO mice, however, indicates that ER-alpha is necessary for PPT's eating-inhibitory action and that any PPT-induced activation of non-ER-alpha estrogen receptors is not sufficient to inhibit eating. Finally, the rapid induction of c-Fos in CRH-expressing cells in the PVN by PPT suggests that PPT elicits a neural response that is similar to that elicited by stress or aversive emotional stimuli.

Flightless I (Drosophila) homolog facilitates chromatin accessibility of the estrogen receptor α target genes in MCF-7 breast cancer cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jeong, Kwang Won, E-mail: kwjeong@gachon.ac.kr

2014-04-04

Highlights: • H3K4me3 and Pol II binding at TFF1 promoter were reduced in FLII-depleted MCF-7 cells. • FLII is required for chromatin accessibility of the enhancer of ERalpha target genes. • Depletion of FLII causes inhibition of proliferation of MCF-7 cells. - Abstract: The coordinated activities of multiple protein complexes are essential to the remodeling of chromatin structure and for the recruitment of RNA polymerase II (Pol II) to the promoter in order to facilitate the initiation of transcription in nuclear receptor-mediated gene expression. Flightless I (Drosophila) homolog (FLII), a nuclear receptor coactivator, is associated with the SWI/SNF-chromatin remodeling complexmore » during estrogen receptor (ER)α-mediated transcription. However, the function of FLII in estrogen-induced chromatin opening has not been fully explored. Here, we show that FLII plays a critical role in establishing active histone modification marks and generating the open chromatin structure of ERα target genes. We observed that the enhancer regions of ERα target genes are heavily occupied by FLII, and histone H3K4me3 and Pol II binding induced by estrogen are decreased in FLII-depleted MCF-7 cells. Furthermore, formaldehyde-assisted isolation of regulatory elements (FAIRE)-quantitative polymerase chain reaction (qPCR) experiments showed that depletion of FLII resulted in reduced chromatin accessibility of multiple ERα target genes. These data suggest FLII as a key regulator of ERα-mediated transcription through its role in regulating chromatin accessibility for the binding of RNA Polymerase II and possibly other transcriptional coactivators.« less

Estrogen-dependent regulation of sodium/hydrogen exchanger-3 (NHE3) expression via estrogen receptor β in proximal colon of pregnant mice.

PubMed

Choijookhuu, Narantsog; Sato, Yoko; Nishino, Tomoya; Endo, Daisuke; Hishikawa, Yoshitaka; Koji, Takehiko

2012-05-01

Although constipation is very common during pregnancy, the exact mechanism is unknown. We hypothesized that the involvement of estrogen receptor (ER) in the regulation of electrolyte transporter in the colon leads to constipation. In this study, the intestines of normal female ICR mouse and pregnant mice were examined for the expression of ERα and ERβ by immunohistochemistry and in situ hybridization. ERβ, but not ERα, was expressed in surface epithelial cells of the proximal, but not distal, colon on pregnancy days 10, 15, and 18, but not day 5, and the number of ERβ-positive cells increased significantly during pregnancy. Expression of NHE3, the gene that harbors estrogen response element, examined by immunohistochemistry and western blotting, was localized in the surface epithelial cells of the proximal colon and increased in parallel with ERβ expression. In ovariectomized mice, NHE3 expression was only marginal and was up-regulated after treatment with 17β-estradiol (E(2)), but not E(2) + ICI 182,780 (estrogen receptor antagonist). Moreover, knock-down of ERβ expression by electroporetically transfected siRNA resulted in a significant reduction of NHE3 expression. These results indicate that ERβ regulates the expression of NHE3 in the proximal colon of pregnant mice through estrogen action, suggesting the involvement of increased sodium absorption by up-regulated NHE3 in constipation during pregnancy.

An alternate pathway for androgen regulation of brain function: Activation of estrogen receptor beta by the metabolite of dihydrotestosterone, 5α-androstane 3β, 17β diol

PubMed Central

Handa, Robert J.; Pak, Toni R.; Kudwa, Andrea E.; Lund, Trent D.; Hinds, Laura

2008-01-01

The complexity of gonadal steroid hormone actions is reflected in their broad and diverse effects on a host of integrated systems including reproductive physiology, sexual behavior, stress responses, immune function, cognition, and neural protection. Understanding the specific contributions of androgens and estrogens in neurons that mediate these important biological processes is central to the study of neuroendocrinology. Of particular interest in recent years has been the biological role of androgen metabolites. The goal of this review is to highlight recent data delineating the specific brain targets for the dihydrotestosterone metabolite, 5α-androstane, 3β, 17β-diol (3β-Diol). Studies using both in vitro and in vivo approaches provide compelling evidence that 3β-Diol is an important modulator of the stress response mediated by the hypothalmo-pituitary-adrenal axis. Further, the actions of 3β-Diol are mediated by estrogen receptors, and not androgen receptors, often through a canonical estrogen response element in the promoter of a given target gene. These novel findings compel us to re-evaluate the interpretation of past studies and the design of future experiments aimed at elucidating the specific effects of androgen receptor signaling pathways. PMID:18067894

Cellular mechanisms of estradiol-mediated sexual differentiation of the brain.

PubMed

Wright, Christopher L; Schwarz, Jaclyn S; Dean, Shannon L; McCarthy, Margaret M

2010-09-01

Gonadal steroids organize the developing brain during a perinatal sensitive period and have enduring consequences for adult behavior. In male rodents testicular androgens are aromatized in neurons to estrogens and initiate multiple distinct cellular processes that ultimately determine the masculine phenotype. Within specific brain regions, overall cell number and dendritic morphology are the principal targets for hormonal organization. Recent advances have been made in elucidating the cellular mechanisms by which the neurological underpinnings of sexually dimorphic physiology and behavior are determined. These include estradiol-mediated prostaglandin synthesis, presynaptic release of glutamate, postsynaptic changes in glutamate receptors and changes in cell adhesion molecules. Sex differences in cell death are mediated by hormonal modulation of survival and death factors such as TNFalpha and Bcl-2/BAX. Copyright 2010 Elsevier Ltd. All rights reserved.

Mechanism of HSV infection through soluble adapter-mediated virus bridging to the EGF receptor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nakano, Kenji, E-mail: kenakano@med.kyushu-u.ac.j; Kobayashi, Masatoshi; Nakamura, Kei-ichiro

2011-04-25

Herpes simplex virus entry into cells requires the binding of envelope glycoprotein D (gD) to an entry receptor. Depending on the cell, entry occurs by different mechanisms, including fusion at the cell surface or endocytosis. Here we examined the entry mechanism through a non-HSV receptor mediated by a soluble bi-specific adapter protein composed of recognition elements for gD and the EGF receptor (EGFR). Virus entered into endosomes using either EGF or an EGFR-specific single chain antibody (scFv) for receptor recognition. Infection was less efficient with the EGF adapter which could be attributed to its weaker binding to a viral gD.more » Infection mediated by the scFv adapter was pH sensitive, indicating that gD-EGFR bridging alone was insufficient for capsid release from endosomes. We also show that the scFv adapter enhanced infection of EGFR-expressing tumor tissue in vivo. Our results indicate that adapters may retarget HSV infection without drastically changing the entry mechanism.« less

Human glutathione S-transferase P1-1 functions as an estrogen receptor α signaling modulator

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Xiyuan; An, Byoung Ha; Kim, Min Jung

2014-09-26

Highlights: • GSTP induces the classical ERα signaling event. • The functional GSTP is a prerequisite for GSTP-induced ERα transcription activity. • The expression of RIP140, a transcription cofactor, was inhibited by GSTP protein. • We propose the novel non-enzymatic role of GSTP. - Abstract: Estrogen receptor α (ERα) plays a crucial role in estrogen-mediated signaling pathways and exerts its action as a nuclear transcription factor. Binding of the ligand-activated ERα to the estrogen response element (ERE) is a central part of ERα-associated signal transduction pathways and its aberrant modulation is associated with many disease conditions. Human glutathione S-transferase P1-1more » (GSTP) functions as an enzyme in conjugation reactions in drug metabolism and as a regulator of kinase signaling pathways. It is overexpressed in tumors following chemotherapy and has been associated with a poor prognosis in breast cancer. In this study, a novel regulatory function of GSTP has been proposed in which GSTP modulates ERE-mediated ERα signaling events. Ectopic expression of GSTP was able to induce the ERα and ERE-mediated transcriptional activities in ERα-positive but GSTP-negative MCF7 human breast cancer cells. This inductive effect of GSTP on the ERE-transcription activity was diminished when the cells express a mutated form of the enzyme or are treated with a GSTP-specific chemical inhibitor. It was found that GSTP inhibited the expression of the receptor interacting protein 140 (RIP140), a negative regulator of ERα transcription, at both mRNA and protein levels. Our study suggests a novel non-enzymatic role of GSTP which plays a significant role in regulating the classical ERα signaling pathways via modification of transcription cofactors such as RIP140.« less

Cordycepin-induced apoptosis and autophagy in breast cancer cells are independent of the estrogen receptor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Choi, Sunga; Lim, Mi-Hee; Kim, Ki Mo

2011-12-15

Cordycepin (3-deoxyadenosine), found in Cordyceps spp., has been known to have many therapeutic effects including immunomodulatory, anti-inflammatory, antimicrobial, and anti-aging effects. Moreover, anti-tumor and anti-metastatic effects of cordycepin have been reported, but the mechanism causing cancer cell death is poorly characterized. The present study was designed to investigate whether the mechanisms of cordycepin-induced cell death were associated with estrogen receptor in breast cancer cells. Exposure of both MDA-MB-231 and MCF-7 human breast cancer cells to cordycepin resulted in dose-responsive inhibition of cell growth and reduction in cell viability. The cordycepin-induced cell death in MDA-MB-231 cells was associated with several specificmore » features of the mitochondria-mediated apoptotic pathway, which was confirmed by DNA fragmentation, TUNEL, and biochemical assays. Cordycepin also caused a dose-dependent increase in mitochondrial translocation of Bax, triggering cytosolic release of cytochrome c and activation of caspases-9 and -3. Interestingly, MCF-7 cells showed autophagy-associated cell death, as observed by the detection of an autophagosome-specific protein and large membranous vacuole ultrastructure morphology in the cytoplasm. Cordycepin-induced autophagic cell death has applications in treating MCF-7 cells with apoptotic defects, irrespective of the ER response. Although autophagy has a survival function in tumorigenesis of some cancer cells, autophagy may be important for cordycepin-induced MCF-7 cell death. In conclusion, the results of our study demonstrate that cordycepin effectively kills MDA-MB-231 and MCF-7 human breast cancer cell lines in culture. Hence, further studies should be conducted to determine whether cordycepin will be a clinically useful, ER-independent, chemotherapeutic agent for human breast cancer. -- Highlights: Black-Right-Pointing-Pointer We studied the mechanism which cordycepin-induced cell death

Estrogens of multiple classes and their role in mental health disease mechanisms.

PubMed

Watson, Cheryl S; Alyea, Rebecca A; Cunningham, Kathryn A; Jeng, Yow-Jiun

2010-08-09

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.

Opioid receptor agonists may favorably affect bone mechanical properties in rats with estrogen deficiency-induced osteoporosis.

PubMed

Janas, Aleksandra; Folwarczna, Joanna

2017-02-01

The results of epidemiological, clinical, and in vivo and in vitro experimental studies on the effect of opioid analgesics on bone are inconsistent. The aim of the present study was to investigate the effect of morphine (an agonist of opioid receptors), buprenorphine (a partial μ opioid receptor agonist and κ opioid receptor antagonist), and naloxone (an antagonist of opioid receptors) on the skeletal system of female rats in vivo. The experiments were carried out on 3-month-old Wistar rats, divided into two groups: nonovariectomized (intact; NOVX) rats and ovariectomized (OVX) rats. The bilateral ovariectomy was performed 7 days before the start of drug administration. Morphine hydrochloride (20 mg/kg/day s.c.), buprenorphine (0.05 mg/kg/day s.c.), or naloxone hydrochloride dihydrate (2 mg/kg/day s.c.) were administered for 4 weeks to NOVX and OVX rats. In OVX rats, the use of morphine and buprenorphine counteracted the development of osteoporotic changes in the skeletal system induced by estrogen deficiency. Morphine and buprenorphine beneficially affected also the skeletal system of NOVX rats, but the effects were much weaker than those in OVX rats. Naloxone generally did not affect the rat skeletal system. The results confirmed the role of opioid receptors in the regulation of bone remodeling processes and demonstrated, in experimental conditions, that the use of opioid analgesics at moderate doses may exert beneficial effects on the skeletal system, especially in estrogen deficiency.

Decursin and decursinol angelate inhibit estrogen-stimulated and estrogen-independent growth and survival of breast cancer cells.

PubMed

Jiang, Cheng; Guo, Junming; Wang, Zhe; Xiao, Bingxiu; Lee, Hyo-Jung; Lee, Eun-Ok; Kim, Sung-Hoon; Lu, Junxuan

2007-01-01

Estrogen and estrogen receptor (ER)-mediated signaling are crucial for the etiology and progression of human breast cancer. Attenuating ER activities by natural products is a promising strategy to decrease breast cancer risk. We recently discovered that the pyranocoumarin compound decursin and its isomer decursinol angelate (DA) have potent novel antiandrogen receptor signaling activities. Because the ER and the androgen receptor belong to the steroid receptor superfamily, we examined whether these compounds affected ER expression and signaling in breast cancer cells. We treated estrogen-dependent MCF-7 and estrogen-independent MDA MB-231 human breast cancer cells with decursin and DA, and examined cell growth, apoptosis, and ERalpha and ERbeta expression in both cell lines - and, in particular, estrogen-stimulated signaling in the MCF-7 cells. We compared these compounds with decursinol to determine their structure-activity relationship. Decursin and DA exerted growth inhibitory effects on MCF-7 cells through G1 arrest and caspase-mediated apoptosis. These compounds decreased ERalpha in MCF-7 cells at both mRNA and protein levels, and suppressed estrogen-stimulated genes. Decursin and the pure antiestrogen Faslodex exerted an additive growth inhibitory effect on MCF-7 cells. In MDA MB-231 cells, these compounds induced cell-cycle arrests in the G1 and G2 phases as well as inducing apoptosis, accompanied by an increased expression of ERbeta. In contrast, decursinol, which lacks the side chain of decursin and DA, did not have these cellular and molecular activities at comparable concentrations. The side chain of decursin and DA is crucial for their anti-ER signaling and breast cancer growth inhibitory activities. These data provide mechanistic rationales for validating the chemopreventive and therapeutic efficacy of decursin and its derivatives in preclinical animal models of breast cancer.

Decursin and decursinol angelate inhibit estrogen-stimulated and estrogen-independent growth and survival of breast cancer cells

PubMed Central

Jiang, Cheng; Guo, Junming; Wang, Zhe; Xiao, Bingxiu; Lee, Hyo-Jung; Lee, Eun-Ok; Kim, Sung-Hoon; Lu, Junxuan

2007-01-01

Introduction Estrogen and estrogen receptor (ER)-mediated signaling are crucial for the etiology and progression of human breast cancer. Attenuating ER activities by natural products is a promising strategy to decrease breast cancer risk. We recently discovered that the pyranocoumarin compound decursin and its isomer decursinol angelate (DA) have potent novel antiandrogen receptor signaling activities. Because the ER and the androgen receptor belong to the steroid receptor superfamily, we examined whether these compounds affected ER expression and signaling in breast cancer cells. Methods We treated estrogen-dependent MCF-7 and estrogen-independent MDA MB-231 human breast cancer cells with decursin and DA, and examined cell growth, apoptosis, and ERα and ERβ expression in both cell lines – and, in particular, estrogen-stimulated signaling in the MCF-7 cells. We compared these compounds with decursinol to determine their structure-activity relationship. Results Decursin and DA exerted growth inhibitory effects on MCF-7 cells through G1 arrest and caspase-mediated apoptosis. These compounds decreased ERα in MCF-7 cells at both mRNA and protein levels, and suppressed estrogen-stimulated genes. Decursin and the pure antiestrogen Faslodex™ exerted an additive growth inhibitory effect on MCF-7 cells. In MDA MB-231 cells, these compounds induced cell-cycle arrests in the G1 and G2 phases as well as inducing apoptosis, accompanied by an increased expression of ERβ. In contrast, decursinol, which lacks the side chain of decursin and DA, did not have these cellular and molecular activities at comparable concentrations. Conclusion The side chain of decursin and DA is crucial for their anti-ER signaling and breast cancer growth inhibitory activities. These data provide mechanistic rationales for validating the chemopreventive and therapeutic efficacy of decursin and its derivatives in preclinical animal models of breast cancer. PMID:17986353

The Oxysterol, 27-Hydroxycholesterol, Links Cholesterol Metabolism to Bone Homeostasis Through Its Actions on the Estrogen and Liver X Receptors

PubMed Central

Nelson, Erik R.; DuSell, Carolyn D.; Wang, Xiaojuan; Howe, Matthew K.; Evans, Glenda; Michalek, Ryan D.; Umetani, Michihisa; Rathmell, Jeffrey C.; Khosla, Sundeep; Gesty-Palmer, Diane

2011-01-01

Osteoporosis and age-related bone loss are important public health concerns. Therefore, there is a high level of interest in the development of medical interventions and lifestyle changes that reduce the incidence of osteoporosis and age-related bone loss. Decreased bone mineral density is associated with high cholesterol, and patients on statins have increased bone mineral densities, strongly implicating cholesterol as a negative regulator of bone homeostasis. In this study, using both molecular and pharmacological approaches, we have been able to demonstrate that the primary cholesterol metabolite, 27-hydroxycholesterol, through its actions on both estrogen receptors and liver X receptors, decreases osteoblast differentiation and enhances osteoclastogenesis, resulting in increased bone resorbtion in mice. Induction of the short heterodimer partner protein by estrogens in osteoblasts can attenuate the liver X receptor-mediated actions of 27-hydroxycholesterol in bone. These data establish a mechanistic link between cholesterol and bone quality, highlight an unexpected target of estrogens in osteoblasts, and define a signaling axis, the therapeutic exploitation of which is likely to yield novel antiosteoporotic drugs. PMID:21933863

Estrogen receptors in neuropeptide Y neurons: at the crossroads of feeding and reproduction.

PubMed

Acosta-Martinez, Maricedes; Horton, Teresa; Levine, Jon E

2007-03-01

Hypothalamic neuropeptide Y (NPY) neurons function as physiological integrators in at least two different neuroendocrine systems - one governing feeding and the other controlling reproduction. Estrogen might modulate both systems by regulating NPY gene expression; it might reduce food intake by suppressing NPY expression, and evoke reproductive hormone surges by stimulating it. How can estrogen exert opposing effects in an ostensibly homogeneous NPY neuronal population? Recent work with immortalized NPY-producing cells suggests that the ratio of estrogen receptor alpha:estrogen receptor beta can determine the direction and temporal pattern of transcriptional responses to estrogen. Because this ratio might itself be physiologically regulated, these findings provide one explanation for multiple neuropeptidergic responses to a single steroid hormone.

GPER - novel membrane estrogen receptor

PubMed Central

Zimmerman, Margaret A.; Budish, Rebecca A.; Kashyap, Shreya; Lindsey, Sarah H.

2016-01-01

The recent discovery of the G protein-coupled estrogen receptor (GPER) presents new challenges and opportunities for understanding the physiology, pathophysiology, and pharmacology of many diseases. This review will focus on the expression and function of GPER in hypertension, kidney disease, atherosclerosis, vascular remodeling, heart failure, reproduction, metabolic disorders, cancer, environmental health, and menopause. Furthermore, this review will highlight the potential of GPER as a therapeutic target. PMID:27154744

Factors Modulating Estrogen Receptor Activity

DTIC Science & Technology

1997-07-01

public release; distribution unlimited The views, opinions and/or findings contained in this report are those of the author( s ) and should not be...TITLE AND SUBTITLE Activity Factors Modulating Estrogen Receptor 6. AUTHOR( S ) Michael J. Garabedian, Ph.D. 7. PERFORMING ORGANIZATION NAME( S ) AND...ADDRESS(ES) New York University Medical Center New York, New York 10016 9. SPONSORING/MONITORING AGENCY NAME( S ) AND ADDRESS(ES) Commander U.S

Regulation of Estrogen Receptor α Expression in the Hypothalamus by Sex Steroids: Implication in the Regulation of Energy Homeostasis.

PubMed

Liu, Xian; Shi, Haifei

2015-01-01

Sex differences exist in the complex regulation of energy homeostasis that utilizes central and peripheral systems. It is widely accepted that sex steroids, especially estrogens, are important physiological and pathological components in this sex-specific regulation. Estrogens exert their biological functions via estrogen receptors (ERs). ERα, a classic nuclear receptor, contributes to metabolic regulation and sexual behavior more than other ER subtypes. Physiological and molecular studies have identified multiple ERα-rich nuclei in the hypothalamus of the central nervous system (CNS) as sites of actions that mediate effects of estrogens. Much of our understanding of ERα regulation has been obtained using transgenic models such as ERα global or nuclei-specific knockout mice. A fundamental question concerning how ERα is regulated in wild-type animals, including humans, in response to alterations in steroid hormone levels, due to experimental manipulation (i.e., castration and hormone replacement) or physiological stages (i.e., puberty, pregnancy, and menopause), lacks consistent answers. This review discusses how different sex hormones affect ERα expression in the hypothalamus. This information will contribute to the knowledge of estrogen action in the CNS, further our understanding of discrepancies in correlation of altered sex hormone levels with metabolic disturbances when comparing both sexes, and improve health issues in postmenopausal women.

Novel drugs that target the estrogen-related receptor alpha: their therapeutic potential in breast cancer

PubMed Central

May, Felicity EB

2014-01-01

The incidence of breast cancer continues to rise: 1.7 million women were diagnosed with and 521,000 women died from breast cancer in 2012. This review considers first current treatment options: surgery; radiotherapy; and systemic endocrine, anti-biological, and cytotoxic therapies. Clinical management includes prevention, early detection by screening, treatment with curative intent, management of chronic disease, and palliative control of advanced breast cancer. Next, the potential of novel drugs that target DNA repair, growth factor dependence, intracellular and intercellular signal transduction, and cell cycle are considered. Estrogen-related receptor alpha has attracted attention as a therapeutic target in triple-negative breast cancers with de novo resistance to, and in breast cancers with acquired resistance to, endocrine therapies such as antiestrogens and aromatase inhibitors. Estrogen-related receptor alpha is an orphan receptor and transcription factor. Its activity is regulated by coregulator proteins and posttranslational modification. It is an energy sensor that controls adaptation to energy demand and may facilitate glycolytic metabolism and mitochondrial oxidative respiration in breast cancer cells. Estrogen-related receptor alpha increases breast cancer cell migration, proliferation, and tumor development. It is expressed at high levels in estrogen receptor-negative tumors, and is proposed to activate estrogen-responsive genes in endocrine-resistant tumors. The structures and functions of the ligand-binding domains of estrogen receptor alpha and estrogen-related receptor alpha, their ability to bind estrogens, phytoestrogens, and synthetic ligands, and the effects of ligand agonists, antagonists, and inverse agonists on biological activity, are evaluated. Synthetic ligands of estrogen-related receptor alpha have activity in preclinical models of metabolic disorders, diabetes, osteoporosis, and oncology. The clinical settings in which these novel

Resveratrol inhibits estrogen-induced breast carcinogenesis through induction of NRF2-mediated protective pathways

PubMed Central

Singh, Bhupendra; Shoulson, Rivka; Chatterjee, Anwesha; Ronghe, Amruta; Bhat, Nimee K.; Dim, Daniel C.; Bhat, Hari K.

2014-01-01

The importance of estrogens in the etiology of breast cancer is widely recognized. Estrogen-induced oxidative stress has been implicated in this carcinogenic process. Resveratrol (Res), a natural antioxidant phytoestrogen has chemopreventive effects against a variety of illnesses including cancer. The objective of the present study was to characterize the mechanism(s) of Res-mediated protection against estrogen-induced breast carcinogenesis. Female August Copenhagen Irish rats were treated with 17β-estradiol (E2), Res and Res + E2 for 8 months. Cotreatment of rats with Res and E2 inhibited E2-mediated proliferative changes in mammary tissues and significantly increased tumor latency and reduced E2-induced breast tumor development. Resveratrol treatment alone or in combination with E2 significantly upregulated expression of nuclear factor erythroid 2-related factor 2 (NRF2) in mammary tissues. Expression of NRF2-regulated antioxidant genes NQO1, SOD3 and OGG1 that are involved in protection against oxidative DNA damage was increased in Res- and Res + E2-treated mammary tissues. Resveratrol also prevented E2-mediated inhibition of detoxification genes AOX1 and FMO1. Inhibition of E2-mediated alterations in NRF2 promoter methylation and expression of NRF2 targeting miR-93 after Res treatment indicated Res-mediated epigenetic regulation of NRF2 during E2-induced breast carcinogenesis. Resveratrol treatment also induced apoptosis and inhibited E2-mediated increase in DNA damage in mammary tissues. Increased apoptosis and decreased DNA damage, cell migration, colony and mammosphere formation in Res- and Res + E2-treated MCF-10A cells suggested a protective role of Res against E2-induced mammary carcinogenesis. Small-interfering RNA-mediated silencing of NRF2 inhibited Res-mediated preventive effects on the colony and mammosphere formation. Taken together, these results suggest that Res inhibits E2-induced breast carcinogenesis via induction of NRF2-mediated protective

Estrogen receptor expert system overview and examples

EPA Science Inventory

The estrogen receptor expert system (ERES) is a rule-based system developed to prioritize chemicals based upon their potential for binding to the ER. The ERES was initially developed to predict ER affinity of chemicals from two specific EPA chemical inventories, antimicrobial pe...

Disruption of estrogen homeostasis as a mechanism for uterine toxicity in Wistar Han rats treated with tetrabromobisphenol A

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sanders, J. Michael, E-mail: sander10@mail.nih.gov; Coulter, Sherry J.; Knudsen, Gabriel A.

Chronic oral treatment of tetrabromobisphenol A (TBBPA) to female Wistar Han rats resulted in increased incidence of cell proliferation at 250 mg/kg and tumor formation in the uterus at higher doses. The present study was designed to test the hypothesis that disruption of estrogen homeostasis was a major mode-of-action for the observed effects. Biological changes were assessed in serum, liver, and the proximal (nearest the cervix) and distal (nearest the ovaries) sections of the uterine horn of Wistar Han rats 24 h following administration of the last of five daily oral doses of 250 mg/kg. Expression of genes associated withmore » receptors, biosynthesis, and metabolism of estrogen was altered in the liver and uterus. TBBPA treatment also resulted in changes in expression of genes associated with cell division and growth. Changes were also observed in the concentration of thyroxine in serum and in expression of genes in the liver and uterus associated with thyroid hormone receptors. Differential expression of some genes was tissue-dependent or specific to tissue location in the uterus. The biological responses observed in the present study support the hypothesis that perturbation of estrogen homeostasis is a major mode-of-action for TBBPA-mediated cell proliferation and tumorigenesis previously observed in the uterus of TBBPA-treated Wistar Han rats. - Highlights: • Perturbation of estrogen homeostasis in TBBPA-treated female rats was investigated. • Gene expression changes were observed in the liver and uterus of these rats. • Genes associated with estrogen biosynthesis and metabolism were affected. • Genes associated with thyroid homeostasis and cell division/growth were affected. • A mechanism of uterine toxicity via endocrine disruption was indicated.« less