Xenoestrogen regulation of ERα/ERβ balance in hormone-associated cancers

Resorcinol as "endocrine disrupting chemical": Are thyroid-related adverse effects adequately documented in reptiles? In vivo experimentation in lizard Podarcis siculus

The endocrine system and particularly thyroid hormones regulate almost all physiological processes in a timely manner in all vertebrates, from fish to reptiles to mammals, so risk assessment of endocrine disrupting chemicals (EDCs) is extremely important given their persistent presence in all environmental matrices. Resorcinol, as well as nonylphenol, octylphenol, and bisphenol A, F, S, are non-Halogenated Phenolic (non-HPCs) Chemicals known as EDCs. Resorcinol is a particular example in that most studies are based exclusively on humans while animal studies are few and often inadequate. The aim of this study was to assess the effects of exposure to different doses of resorcinol on the thyroid gland of the lizard Podarcis siculus during different periods of the thyroid gland activity cycle. Our results showed histopathologic changes in thyroid (follicular cell height increase and colloid area decrease), a thyroid weight increase in combination with serum T4 and T3 decrease, serum TSH, TRH increase in male lizards treated with 0.8,3.9,13.1, and 36.9 mg/kg/d of resorcinol. Besides, we also investigated the impacts of resorcinol treatments on hepatic 5'ORD (type II) deiodinase and hepatic content of T3 and T4. Our findings showed that they are in agreement with in vivo in humans and in rodents data and therefore, resorcinol in reptiles may meet the WHO definition of ECDs.

17β-estradiol in colorectal cancer: friend or foe?

Colorectal cancer (CRC) is a common gastrointestinal malignancy with higher incidence and mortality rates in men compared to women, potentially due to the effects of estrogen signaling. There is substantial evidence supporting the significant role of 17β-Estradiol (E2) in reducing CRC risk in females, although this perspective remains debated. E2 has been demonstrated to inhibit CRC cell proliferation and migration at the cellular level by enhancing DNA mismatch repair, modulating key gene expression, triggering cell cycle arrest, and reducing activity of migration factors. Furthermore, E2 contributes to promote a tumor microenvironment unfavorable for CRC growth by stimulating ERβ expression, reducing inflammatory responses, reversing immunosuppression, and altering the gut microbiome composition. Conversely, under conditions of high oxidative stress, hypoxia, and nutritional deficiencies, E2 may facilitate CRC development through GPER-mediated non-genomic signaling. E2's influence on CRC involves the genomic and non-genomic signals mediated by ERβ and GPER, respectively, leading to its dual roles in anticancer activity and carcinogenesis. This review aims to summarize the potential mechanisms by which E2 directly or indirectly impacts CRC development, providing insights into the phenomenon of sexual dimorphism in CRC and suggesting potential strategies for prevention and treatment.

Application of the Key Characteristics of Carcinogens to Bisphenol A

The ten key characteristics (KCs) of carcinogens are based on characteristics of known human carcinogens and encompass many types of endpoints. We propose that an objective review of the large amount of cancer mechanistic evidence for the chemical bisphenol A (BPA) can be achieved through use of these KCs. A search on metabolic and mechanistic data relevant to the carcinogenicity of BPA was conducted and web-based software tools were used to screen and organize the results. We applied the KCs to systematically identify, organize, and summarize mechanistic information for BPA, and to bring relevant carcinogenic mechanisms into focus. For some KCs with very large data sets, we utilized reviews focused on specific endpoints. Over 3000 studies for BPA from various data streams (exposed humans, animals, in vitro and cell-free systems) were identified. Mechanistic data relevant to each of the ten KCs were identified, with receptor-mediated effects, epigenetic alterations, oxidative stress, and cell proliferation being especially data rich. Reactive and bioactive metabolites are also associated with a number of KCs. This review demonstrates how the KCs can be applied to evaluate mechanistic data, especially for data-rich chemicals. While individual entities may have different approaches for the incorporation of mechanistic data in cancer hazard identification, the KCs provide a practical framework for conducting an objective examination of the available mechanistic data without a priori assumptions on mode of action. This analysis of the mechanistic data available for BPA suggests multiple and inter-connected mechanisms through which this chemical can act.

The impacts of exposure to bisphenol A in the adult female prostate Meriones unguiculatus

The female prostate is associated with the urogenital system and presents homology in morphological terms with the male prostate. Due to its responsiveness to endogenous hormones, this gland is under a constant risk of developing prostatic pathologies and neoplasia when exposed to certain exogenous compounds. Bisphenol A (BPA) is an endocrine disruptor found in different plastic and resin products. Studies have emphasized the effects of perinatal exposure to this compound on different hormone-responsive organs. However, there have been few studies highlighting the influence on female prostate morphology of perinatal exposure to BPA. The objective of this study was to describe the histopathological alterations caused by perinatal exposure to BPA (50 µg/kg) and 17-β estradiol (E2) (35 µg/kg) in the prostate of adult female gerbils. The results showed that E2 and BPA induced proliferative lesions in the female prostate and acted along similar pathways by modulating steroid receptors in the epithelium. BPA was also found to be a pro-inflammatory and pro-angiogenic agent. The impacts of both agents were marked in the prostatic stroma. An increase in the thickness of the smooth muscle layer and a decrease in AR expression were observed, but no alterations in the expression of ERα and ERβ, leading to estrogenic sensitivity of the prostate. However, a peculiar response of the female prostate was to diminish the collagen frequency under BPA exposure correlated to smooth muscle layer. These data therefore indicate the development of features related to estrogenic and non-estrogenic tissue repercussions by BPA perinatally exposure in gerbil female prostate.

Cyclopia extracts act as selective estrogen receptor subtype downregulators in estrogen receptor positive breast cancer cell lines: Comparison to standard of care breast cancer endocrine therapies and a selective estrogen receptor agonist and antagonist

Breast cancer is the most diagnosed type of cancer amongst women in economically developing countries and globally. Most breast cancers express estrogen receptor alpha (ERα) and are categorized as positive (ER+) breast cancer. Endocrine therapies such as, selective estrogen receptor modulators (SERMs), aromatase inhibitors (AIs), and selective estrogen receptor downregulators (SERDs) are used to treat ER+ breast cancer. However, despite their effectiveness, severe side-effects and resistance are associated with these endocrine therapies. Thus, it would be highly beneficial to develop breast cancer drugs that are as effective as current therapies, but less toxic with fewer side effects, and less likely to induce resistance. Extracts of Cyclopia species, an indigenous South African fynbos plant, have been shown to possess phenolic compounds that exhibit phytoestrogenic and chemopreventive activities against breast cancer development and progression. In the current study, three well characterized Cyclopia extracts, SM6Met, cup of tea (CoT) and P104, were examined for their abilities to modulate the levels of the estrogen receptor subtypes, estrogen receptor alpha and estrogen receptor beta (ERβ), which have been recognized as crucial to breast cancer prognosis and treatment. We showed that the Cyclopia subternata Vogel (C. subternata Vogel) extracts, SM6Met and cup of tea, but not the C. genistoides extract, P104, reduced estrogen receptor alpha protein levels while elevating estrogen receptor beta protein levels, thereby reducing the ERα:ERβ ratio in a similar manner as standard of care breast cancer endocrine therapies such as fulvestrant (selective estrogen receptor downregulator) and 4-hydroxytamoxifen (elective estrogen receptor modulator). Estrogen receptor alpha expression enhances the proliferation of breast cancer cells while estrogen receptor beta inhibits the proliferative activities of estrogen receptor alpha. We also showed that in terms of the molecular mechanisms involved all the Cyclopia extracts regulated estrogen receptor alpha and estrogen receptor beta protein levels through both transcriptional and translational, and proteasomal degradation mechanisms. Therefore, from our findings, we proffer that the C. subternata Vogel extracts, SM6Met and cup of tea, but not the C. genistoides extract, P104, selectively modulate estrogen receptor subtypes levels in a manner that generally supports inhibition of breast cancer proliferation, thereby demonstrating attributes that could be explored as potential therapeutic agents for breast cancer.

To Waste or Not to Waste: Questioning Potential Health Risks of Micro- and Nanoplastics with a Focus on Their Ingestion and Potential Carcinogenicity

Micro- and nanoplastics (MNPs) are recognized as emerging contaminants, especially in food, with unknown health significance. MNPs passing through the gastrointestinal tract have been brought in context with disruption of the gut microbiome. Several molecular mechanisms have been described to facilitate tissue uptake of MNPs, which then are involved in local inflammatory and immune responses. Furthermore, MNPs can act as potential transporters ("vectors") of contaminants and as chemosensitizers for toxic substances ("Trojan Horse effect"). In this review, we summarize current multidisciplinary knowledge of ingested MNPs and their potential adverse health effects. We discuss new insights into analytical and molecular modeling tools to help us better understand the local deposition and uptake of MNPs that might drive carcinogenic signaling. We present bioethical insights to basically re-consider the "culture of consumerism." Finally, we map out prominent research questions in accordance with the Sustainable Development Goals of the United Nations.

Xenoestrogens impact brain estrogen receptor signaling during the female lifespan: A precursor to neurological disease?

Xenoestrogens, foreign synthetic chemicals mimicking estrogens, are lurking in our surroundings. Climate change may alter their toxicity and bioavailability. Since xenoestrogens have extremely high lipid solubility and are structurally similar to natural endogenous estrogens, they can bind to estrogen receptors (ERs) -alpha (ER-α) and -beta (ER-β). Scientific evidence accumulated over the past decades have suggested that natural 17β-estradiol (E2; a potent estrogen), via activation of its receptors, plays a pivotal role in regulation of brain development, differentiation, metabolism, synaptic plasticity, neuroprotection, cognition, anxiety, body temperature, feeding and sexual behavior. In the brain, ER-β is predominantly expressed in the various regions, including cerebral cortex and hippocampus, that have been shown to play a key role in cognition. Therefore, disturbances in function of ER-β mediated E2 signaling by xenoestrogens can lead to deleterious effects that potentiate a variety of neurological diseases starting from prenatal to post-menopause in women. The goal of this review is to identify the possible neurological effects of xenoestrogens that can alter estrogen receptor-mediated signaling in the brain during different stages of the female lifespan.

Methylparaben-induced regulation of estrogenic signaling in human neutrophils

Parabens, including the most common methylparaben (MeP), are popular preservatives, which possess estrogenic activity. The aims of this study were to assess the impact of MeP on estrogen receptors (ERs) and/or NF-κB-dependent generation of IL-8 and production of nitric oxide (NO), and also to verify the hypothesis about the crosstalk of ERs with NF-κB in xenoestrogen-exposed neutrophils. Human neutrophils were incubated for 20-h with MeP (0.06 μM) and/or ER antagonist (1 μM) and/or NF-κB inhibitor (100 μM). After the isolation of cell lysates and cytoplasmic and nuclear fraction, the expression of ERα, ERβ, p-IKKα/β, p65 NF-κB, and inducible nitric oxide synthase (iNOS) was measured by Western blot analysis, The concentration of NO was evaluated by Griess reaction, and that of IL-8 was measured by ELISA. The results showed that MeP modulated the expression of ERα, but not ERβ. Exposure to paraben activated iKKα/β-dependent NF-κB pathway, but translocation of p65 NF-κB into the cell nucleus was inhibited by ERs. MeP also decreased the iNOS-dependent production of NO, but did not influence the secretion of IL-8 by neutrophils. The study indicates that MeP may affect the functioning of human neutrophils by modulating intracellular signal transduction pathways, including ERs and NF-κB pathway.

The extra-nuclear interactome of the estrogen receptors: implications for physiological functions

Over the last decades, a great body of evidence has defined a novel view of the cellular mechanism of action of the steroid hormone 17β-estradiol (E2) through its estrogen receptors (i.e., ERα and ERβ). It is now clear that the E2-activated ERs work both as transcription factors and extra-nuclear plasma membrane-localized receptors. The activation of a plethora of signal transduction cascades follows the E2-dependent engagement of plasma membrane-localized ERs and is required for the coordination of gene expression, which ultimately controls the occurrence of the pleiotropic effects of E2. The definition of the molecular mechanisms by which the ERs locate at the cell surface (i.e., palmitoylation and protein association) determined the quest for understanding the specificity of the extra-nuclear E2 signaling. The use of mice models lacking the plasma membrane ERα localization unveiled that the extra-nuclear E2 signaling is operational in vivo but tissue-specific. However, the underlying molecular details for such ERs signaling diversity in the perspective of the E2 physiological functions in the different cellular contexts are still not understood. Therefore, to gain insights into the tissue specificity of the extra-nuclear E2 signaling to physiological functions, here we reviewed the known ERs extra-nuclear interactors and tried to extrapolate from available databases the ERα and ERβ extra-nuclear interactomes. Based on literature data, it is possible to conclude that by specifically binding to extra-nuclear localized proteins in different sub-cellular compartments, the ERs fine-tune their molecular activities. Moreover, we report that the context-dependent diversity of the ERs-mediated extra-nuclear E2 actions can be ascribed to the great flexibility of the physical structures of ERs and the spatial-temporal organization of the logistics of the cells (i.e., the endocytic compartments). Finally, we provide lists of proteins belonging to the potential ERα and ERβ extra-nuclear interactomes and propose that the systematic experimental definition of the ERs extra-nuclear interactomes in different tissues represents the next step for the research in the ERs field. Such characterization will be fundamental for the identification of novel druggable targets for the innovative treatment of ERs-related diseases.

The Peculiar Estrogenicity of Diethyl Phthalate: Modulation of Estrogen Receptor α Activities in the Proliferation of Breast Cancer Cells

Phthalates comprise a group of synthetic chemicals present in the environment because of their wide use as plasticizers and as additives in products for personal care. Among others, diethyl phthalate (DEP) is largely used in products for infants, children, and adults, in which its exposure has been correlated with an increased risk of breast cancer. The adverse health outcomes deriving from phthalate exposure have been associated with their activity as endocrine disruptors (EDCs) of the steroid and thyroid hormone signaling by affecting developmental and reproductive health, and even carcinogenicity. However, the estrogen disruptor activities of DEP are still controversial, and the mechanism at the root of the estrogenic-disrupting action of DEP remains to be clarified. Here, we evaluated the DEP mechanism of action on the activation status of estrogen receptor α (ERα) by analyzing the receptor's phosphorylation as well as both nuclear and extra-nuclear pathways triggered by the receptor to modulate the proliferation of breast cancer cells. Although DEP does not bind to ERα, our results suggest that this phthalate ester exerts multiple parallel interactions with ERα signaling and emphasize the importance to determine an appropriate battery of in vitro methods that will include specific molecular mechanisms involved in the endocrine disruption.

NF-κB-An Important Player in Xenoestrogen Signaling in Immune Cells

The proper functioning of the immune system is critical for an effective defense against pathogenic factors such as bacteria and viruses. All the cellular processes taking place in an organism are strictly regulated by an intracellular network of signaling pathways. In the case of immune cells, the NF-κB pathway is considered the key signaling pathway as it regulates the expression of more than 200 genes. The transcription factor NF-κB is sensitive to exogenous factors, such as xenoestrogens (XEs), which are compounds mimicking the action of endogenous estrogens and are widely distributed in the environment. Moreover, XE-induced modulation of signaling pathways may be crucial for the proper development of the immune system. In this review, we summarize the effects of XEs on the NF-κB signaling pathway. Based on our analysis, we constructed a model of XE-induced signaling in immune cells and found that in most cases XEs activate NF-κB. Our analysis indicated that the indirect impact of XEs on NF-κB in immune cells is related to the modulation of estrogen signaling and other pathways such as MAPK and JAK/STAT. We also summarize the role of these aspects of signaling in the development and further functioning of the immune system in this paper.

Alkyphenol Exposure Alters Steroidogenesis in Male Lizard Podarcis siculus

BACKGROUND

Nonylphenol (NP) and Octylphenol (OP) are persistent and non-biodegradable environmental contaminants classified as endocrine disruptor chemicals (EDCs). These compounds are widely used in several industrial applications and present estrogen-like properties, which have extensively been studied in aquatic organisms. The present study aimed to verify the interference of these compounds alone, and in mixture, on the reproductive cycle of the male terrestrial vertebrate Podarcis siculus, focusing mainly on the steroidogenesis process.

METHODS

Male lizards have been treated with different injections of both NP and OP alone and in mixture, and evaluation has been carried out using a histological approach.

RESULTS

Results obtained showed that both substances are able to alter both testis histology and localization of key steroidogenic enzymes, such as 3β-hydroxysteroid dehydrogenase (3β-HSD), 17β- hydroxysteroid dehydrogenase (17β-HSD) and P450 aromatase. Moreover, OP exerts a preponderant effect, and the P450 aromatase represents the major target of both chemicals.

CONCLUSIONS

In conclusion, NP and OP inhibit steroidogenesis, which in turn may reduce the reproductive capacity of the specimens.

OctylPhenol (OP) Alone and in Combination with NonylPhenol (NP) Alters the Structure and the Function of Thyroid Gland of the Lizard Podarcis siculus

Different environmental contaminants disturb the thyroid system at many levels. AlkylPhenols (APs), by-products of microbial degradation of AlkylPhenol Polyethoxylates (APEOs), constitute an important class of Endocrine Disrupting Chemicals (EDCs), the two most often used environmental APs being 4-nonylphenol (4-NP) and 4-tert-octylphenol (4-t-OP). The purpose of the present study was to investigate the effects on the thyroid gland of the bioindicator Podarcis siculus of OP alone and in combination with NP. We used radioimmunoassay to determine their effects on plasma 3,3',5-triiodo-L-thyronine (T₃), 3,3',5,5'-L-thyroxine (T₄), thyroid-stimulating hormone (TSH), and thyrotropin-releasing hormone (TRH) levels in adult male lizards. We also investigated the impacts of AP treatments on hepatic 5'ORD (type II) deiodinase and hepatic content of T₃ and T₄. After OP and OP + NP administration, TRH levels increased, whereas TSH, T₃, and T₄ levels decreased. Lizards treated with OP and OP + NP had a higher concentration of T₃ in the liver and 5'ORD (type II) activity, whereas T₄ concentrations were lower than that observed in the control group. Moreover, histological examination showed that the volume of the thyroid follicles became smaller in treated lizards suggesting that that thyroid follicular epithelial cells were not functionally active following treatment. This data collectively suggest a severe interference with hypothalamus-pituitary-thyroid axis and a systemic imbalance of thyroid hormones.

The impact of bisphenols on reproductive system and on offspring in pigs - A review 2011-2020

This study summarizes the knowledge about effects of bisphenol A (BPA) and its analogues on reproduction of pigs and some parameters of their offspring during period 2011-2020. Bisphenols are known as one of the most harmful environmental toxicants with endocrine-disrupting properties. One study in the reference period related to male reproductive system. Treatment with an antagonist of G-protein coupled estrogen receptor (GPER) - G15, and bisphenol A and its analogues, tetrabromobisphenol A (TBBPA) and tetrachromobisphenol A (TCBPA) diversely disrupted protein molecules controlling the biogenesis and function of microRNA in Leydig cells. Nine studies examined the effect of BPA, bisphenol S (BPS) or fluorene-9-bisphenol (BHPF) on female reproductive system. From the possible protective effect's point of view seems to be perspective the administration of melatonin in BPA-exposed oocytes. Finally, two studies were found to evaluate the maternal exposure to BPA on offspring's meat quality, muscle metabolism and oxidative stress. Administration of methyl donor improved antioxidant enzymes activity and reduced oxidative stress in piglets.

Ouabain and Digoxin Activate the Proteasome and the Degradation of the ERα in Cells Modeling Primary and Metastatic Breast Cancer

Simple Summary

Breast cancer (BC) treatment relies on the detection of the estrogen receptor α (ERα). ERα-expressing BC patients are treated with anti-estrogen drugs (i.e., tamoxifen and fulvestrant). Despite their proven efficacy, these drugs cause serious side effects in a significant fraction of the patients, including both tumor insurgence in secondary organs, and resistant phenotypes, which result in a relapsing disease with scarce treatment options. Thus, new drugs for treatment of primary and metastatic BC (MBC) are needed. Here, we report the characterization of two cardiac glycosides (CGs) (i.e., ouabain and digoxin), approved by the FDA for treatment of heart disease, as novel ‘anti-estrogen’-like drugs. We found that these drugs induce ERα degradation, and prevent the proliferation of cellular models of primary and metastatic BC cells. Remarkably, we discovered that these CGs are activators of the proteasome, and therefore may be repurposed for treatment not only of BC, but also for other proteasome-based diseases.

Abstract

Estrogen receptor α expressing breast cancers (BC) are classically treated with endocrine therapy. Prolonged endocrine therapy often results in a metastatic disease (MBC), for which a standardized effective therapy is still lacking. Thus, new drugs are required for primary and metastatic BC treatment. Here, we report that the Food and Drug Administration (FDA)-approved drugs, ouabain and digoxin, induce ERα degradation and prevent proliferation in cells modeling primary and metastatic BC. Ouabain and digoxin activate the cellular proteasome, instigating ERα degradation, which causes the inhibition of 17β-estradiol signaling, induces the cell cycle blockade in the G2 phase, and triggers apoptosis. Remarkably, these effects are independent of the inhibition of the Na/K pump. The antiproliferative effects of ouabain and digoxin occur also in diverse cancer models (i.e., tumor spheroids and xenografts). Additionally, gene profiling analysis reveals that these drugs downregulate the expression of genes related to endocrine therapy resistance. Therefore, ouabain and digoxin behave as ‘anti-estrogen’-like drugs, and are appealing candidates for the treatment of primary and metastatic BCs.

ET-1 regulates the human umbilical vein endothelial cell cycle by adjusting the ERβ/FOXN1 signaling pathway

Background

Atherosclerosis (AS) is a chronic and progressive disease primarily induced by inflammation of the arterial blood vessel wall. Investigating the function and molecular regulation mechanisms of ET-1, ERβ, and FOXN1 in disease models will provide new targets and means for clinical treatment.

Methods

The effects of ET-1 on oxidative stress in HUVEC were verified through quantitative polymerase chain reaction (qPCR), western blot, flow cytometry, as well as dual luciferase reporter gene and biochemical assays.

Results

Compared with the ET-1+ negative control (NC) group, the ERβ messenger ribonucleic acid (mRNA) expression level was significantly reduced, and the FOXN1 mRNA expression level increased markedly in the ET-1 + ERβ small interfering ribonucleic acid (siRNA) group. Meanwhile, the FOXN1 mRNA expression level was significantly reduced in the ET-1 + FOXN1 siRNA group. FOXN1 promoter luciferase reporter gene activity was notably enhanced in the ERβ siRNA group compared with the siRNA control group. Compared with the ET-1 + NC group, the levels of reaction oxygen species (ROS) in the ET-1 + ERβ siRNA group increased considerably, the superoxide dismutase (SOD) level was significantly reduced, and the G0/G1 phase cell ratio was reduced. In addition, the protein expression of ERβ and cyclin B1 (CCNB1) was markedly reduced, whereas the protein expression of cyclin A2 (CCNA2), cyclin D1 (CCND1), and cyclin E1 (CCNE1) increased substantially. The opposite result was observed in the ET-1 + FOXN1 siRNA group.

Conclusions

ET-1 can contribute to the expression of ERβ and FOXN1. ERβ can inhibit the expression of FOXN1 by regulating promoter activity. The ET-1/ERβ/FOXN1 signaling pathway is involved in the regulation of oxidative stress and cycle progression in HUVEC. This study provides a new mechanism for the regulation of umbilical vein endothelial cells. The ET-1/ERβ/FOXN1 signaling pathway may provide novel therapeutic targets and strategies for the treatment of atherosclerosis.

Effects of alkylphenols mixture on the adrenal gland of the lizard Podarcis sicula

Alkylphenols (AP) are widespread environmental compounds belonging to the large family of substances known as Endocrine Disrupting Chemicals (EDCs). The present study was carried out to assess the effects of Octylphenol (OP) alone and in combination with Nonylphenol (NP) on the hypothalamus-pituitary-adrenal gland (HPA) axis of the lizard Podarcis sicula. Lizards are good bioindicators due to their features such as wide distribution, large population and good sensitivity to contaminants. Results obtained showed a time and dose-dependent stimulation of the HPA together with a high variation of both catecholamine plasma levels and greater vascularization and hypertrophy of steroidogenic cord of adrenal gland after both OP and OP + NP treatments. Interestingly, the OP + NP mixture treatment has provoked a state of stress of the adrenal gland which in fact appeared to be characterized by the presence of a marked macrophage infiltration which can be seen especially close to the connective capsule surrounding the gland. This macrophage infiltration could be an evidence of a particularly pronounced inflammatory state to indicate, probably, an animal's response to a non-physiological situation.

Unexpected Impact of a Hepatitis C Virus Inhibitor on 17β-Estradiol Signaling in Breast Cancer

17β-Estradiol (E2) controls diverse physiological processes, including cell proliferation, through its binding to estrogen receptor α (ERα). E2:ERα signaling depends on both the receptor subcellular localization (e.g., nucleus, plasma membrane) and intracellular ERα abundance. Indeed, the control of ERα levels is necessary for the effects of E2, and E2 itself induces ERα degradation and cell proliferation in parallel. Thus, the modulation of intracellular ERα levels is a critical parameter for E2-induced cell proliferation. Therefore, we used this parameter as a bait to identify compounds that influence ERα levels and E2-dependent proliferation in breast cancer (BC) cells from a library of Food and Drug Administration (FDA)-approved drugs. We found that telaprevir (Tel) reduces ERα levels and inhibits BC cell proliferation. Tel is an inhibitor of the hepatitis C virus (HCV) NS3/4A serine protease, but its effect on E2:ERα signaling has not been investigated. Here, for the first time, we analyzed the effects of Tel on intracellular ERα levels and E2:ERα signaling to cell proliferation in different ERα-expressing BC cell lines. Overall, our findings demonstrate that Tel reduces intracellular ERα levels, deregulates E2:ERα signaling and inhibits E2-induced proliferation in BC cells and suggest the potential drug repurposing of Tel for the treatment of BC.

Real-time measurement of E2: ERα transcriptional activity in living cells

Kinetic analyses of diverse physiological processes have the potential to unveil new aspects of the molecular regulation of cell biology at temporal levels. 17β-estradiol (E2) regulates diverse physiological effects by binding to the estrogen receptor α (ERα), which primarily works as a transcription factor. Although many molecular details of the modulation of ERα transcriptional activity have been discovered including the impact of receptor plasma membrane localization and its relative E2-evoked signaling, the knowledge of real-time ERα transcriptional dynamics in living cells is lacking. Here, we report the generation of MCF-7 and HeLa cells stably expressing a modified luciferase under the control of an E2-sensitive promoter, which activity can be continuously monitored in living cells and show that E2 induces a linear increase in ERα transcriptional activity. Ligand-independent (e.g., epidermal growth factor) receptor activation was also detected in a time-dependent manner. Kinetic profiles of ERα transcriptional activity measured in the presence of both receptor antagonists and inhibitors of ERα plasma membrane localization reveal a biphasic dynamic of receptor behavior underlying novel aspects of receptor-regulated transcriptional effects. Finally, analysis of the rate of the dose-dependent E2 induction of ERα transcriptional activity demonstrates that low doses of E2 induce an effect identical to that determined by high concentrations of E2 as a function of the duration of hormone administration. Overall, we present the characterization of sensitive stable cell lines were to study the kinetic of E2 transcriptional signaling and to identify new aspects of ERα function in different physiological or pathophysiological conditions.

Divergent Effects of Daidzein and its Metabolites on Estrogen-Induced Survival of Breast Cancer Cells

Although soy consumption is associated with breast cancer prevention, the low bioavailability and the extensive metabolism of soy-active components limit their clinical application. Here, the impact of daidzein (D) and its metabolites on estrogen-dependent anti-apoptotic pathway has been evaluated in breast cancer cells. In estrogen receptor α-positive breast cancer cells treated with D and its metabolites, single or in mixture, ERα activation and Neuroglobin (NGB) levels, an anti-apoptotic estrogen/ERα-inducible protein, were evaluated. Moreover, the apoptotic cascade activation, as well as the cell number after stimulation was assessed in the absence/presence of paclitaxel to determine the compound effects on cell susceptibility to a chemotherapeutic agent. Among the metabolites, only D-4'-sulfate maintains the anti-estrogenic effect of D, reducing the NGB levels and rendering breast cancer cells more prone to the paclitaxel treatment, whereas other metabolites showed estrogen mimetic effects, or even estrogen independent effects. Intriguingly, the co-stimulation of D and gut metabolites strongly reduced D effects. The results highlight the important and complex influence of metabolic transformation on isoflavones physiological effects and demonstrate the need to take biotransformation into account when assessing the potential health benefits of consumption of soy isoflavones in cancer.

Abnormal Expression of ERα in Cholangiocytes of Patients With Primary Biliary Cholangitis Mediated Intrahepatic Bile Duct Inflammation

ERα, one of the classical receptors of estrogen, has been found to be abnormally up-regulated in patients with primary biliary cholangitis (PBC), which is an important factor leading to ductopenia. ERα-mediated signaling pathways are involved in proliferation of human intrahepatic biliary epithelial cells (HiBECs) and portal inflammation. Our previous studies have shown that the expression levels of ERα in the liver tissues of PBC patients are positively correlated with the levels of serum pro-inflammatory cytokines. The present study was designed to assess the relationship between abnormal ERα expression in small bile ducts and the progression of PBC. We examined the levels of multiple cytokines and analyzed their relationship with clinical parameters of livers functions in a cohort of 43 PBC patients and 45 healthy controls (HC). The levels of ERα expression and the relation with the levels of cytokines were further assessed. The localization of cytokines and ERα-mediated signaling pathways in liver were examined using immunohistochemistry. The possible underlying mechanisms of these alterations in PBC were explored in vitro. Our results demonstrated that the levels of IL-6, IL-8, and TNF-α were increased in PBC patients, and positively correlated with the serum AKP levels and ERα expression levels. Moreover, the expression of these cytokines were up-regulated in HiBECs that were stimulated with 17β-estradiol and PPT (an ERα agonist) and they also were positive in intrahepatic bile duct of PBC patients. The ERα-mediated expression of pro-inflammatory cytokines was induced by JNK, P38, and STAT3 phosphorylation in HiBECs. In addition, the CD54 expression was increased in HiBECs after ERα activation, which induced peripheral blood monouclear cells (PBMCs) recruitment. In conclusion, the present study highlighted a key role of abnormal ERα expression in inducing an inflammatory phenotype of HiBECs, which was critical in the development of inflammation and damage in small bile duct.

17α-Ethynylestradiol and 4-nonylphenol stimulate lung adenocarcinoma cell production in xenoestrogenic way

Lung cancer has been one of the major cancers leading to mortalities worldwide. In addition to smoking, estrogen is considered to play an important role in the lung cancer development because women have a higher proportion of adenocarcinoma than men. In the environment, there are many metabolites and waste products that mimic human estrogen structurally and functionally. 17α-Ethynylestradiol (EE2) which is used as an oral contraceptive is released into wastewater after being utilized. Moreover, 4-nonylphenol (NP) which is found in the petrochemical products and air pollutants reveals estrogenic activity. In the present study, 17β-estradiol (E2), EE2, and NP are administered to stimulate male lung adenocarcinoma cells (A549) and female lung adenocarcinoma cells (H1435). The results demonstrate that EE2 and NP stimulate A549 and H1435 cells proliferation in a dose- and time-dependent manner. Both estrogen receptors α and β are simultaneously activated. In response to estrogens, up-regulation of the epidermal growth factor receptor and extracellular signal-regulated kinase expression occurs. In conclusion, this is the first study to report that EE2 and NP exert a biotoxic effect to stimulate the proliferation of both male and female lung cancer cell in a dose- and time- dependent manner. The environmental hormones posing new challenges for lung cancer deserve further investigation.

Neutrophils life under estrogenic and xenoestrogenic control

Over 100 years ago, scientists had identified cells that represent the most abundant population of peripheral blood leukocytes; they called this population neutrophils. Day by day, the knowledge specific to neutrophils is augmented with new and often surprising aspects and facts about neutrophils' life or death. Estrogens (estrone, estriol, and estradiol) are relevant for the regulation of immune responses that are related with neutrophils. An understanding of the molecular mechanism of the action of endogenous hormones allows us to predict the effects of the substances that commonly occur in an environment with estrogen-like properties (xenoestrogens (e.g., bisphenol A, DDT, tributyltin, polychlorinated biphenyls, nonylphenol and octylphenol)). Therefore, we summarize current literature on the impact of estrogens and xenoestrogens, on each aspect of neutrophil life, as well as describe its mechanism of actions in neutrophils.

Preventative effects of resveratrol and estradiol on streptozotocin-induced diabetes in ovariectomized mice and the related mechanisms

Resveratrol, a non-flavonoid polyphenolic compound, is structurally and functionally similar to estrogen and has drawn great attention for its potentially beneficial effects on diabetes. However, it is not known whether it shares the same protective effect against diabetes as estrogen and the underlying mechanisms. The aim of the present study was to investigate the protective effects of phytoestrogen resveratrol and exogenous 17β-estradiol against streptozotocin (STZ)-induced type 1 diabetes. Female mice were ovariectomized (OVX) and chronically injected with different concentrations of resveratrol (0.1, 1 or 10 mg/kg) and 17β-estradiol (0.01, 0.1 or 1 mg/kg) subcutaneously for 4 weeks, and the levels of blood glucose, plasma insulin, plasma antioxidant capacity, the changes of pancreatic islet cells and the expressions of glucose transporter 4 (GLUT4), insulin receptor substrate 1 (IRS-1) and phosphorylation of extracellular signal-regulated kinase (p-ERK) were detected. Resveratrol and 17β-estradiol significantly inhibited the increase of the blood glucose level and the rise of plasma malondialdehyde in STZ-induced diabetic mice, improved the levels of plasma antioxidant capacity and plasma insulin, protected the pancreatic islet cells, and increased the expressions of GLUT4 and IRS-1, but decreased p-ERK expression in skeletal muscle and myocardial tissue. The results suggest that resveratrol or 17β-estradiol shows obvious protection against STZ-induced diabetes in OVX mice, the mechanisms probably involve their ameliorating antioxidant activities and islet function, promoting muscle glucose uptake and inhibiting the expression of p-ERK.

In silico screening for ERα down modulators identifies thioridazine as an anti-proliferative agent in primary, 4OH-tamoxifen-resistant and Y537S ERα-expressing breast cancer cells

PURPOSE

Most breast cancers (BCs) express estrogen receptor α (ERα) and are treated with the endocrine therapy (ET) drugs 4OH-tamoxifen (Tam) and fulvestrant (ICI 182,780; ICI). Unfortunately, a high fraction of ET treated women relapses and becomes resistant to ET. Therefore, additional anti-BC drugs are needed. Recently, we proposed that the identification of novel anti-BC drugs can be achieved using modulation of the intracellular ERα content in BC cells as a pharmacological target. Here, we searched for Food and Drug Administration (FDA)-approved drugs that potentially modify the ERα content in BC cells.

METHODS

We screened in silico more than 60,000 compounds to identify FDA-approved drugs with a gene signature similar to that of ICI. We identified mitoxantrone and thioridazine and tested them in primary, Tam-resistant and genome-edited Y537S ERα-expressing BC cells.

RESULTS

We found that mitoxantrone and thioridazine induced ERα downmodulation and prevented MCF-7 BC cell proliferation. Interestingly, while mitoxantrone was found to be toxic for normal breast epithelial cells, thioridazine showed a preferential activity towards BC cells. Thioridazine also reduced the ERα content and prevented cell proliferation in primary, Tam-resistant and genome-edited Y537S ERα expressing BC cells.

CONCLUSIONS

We suggest that modulation of the intracellular ERα concentration in BC cells can be exploited in in silico screens to identify anti-BC drugs and uncover a re-purposing opportunity for thioridazine in the treatment of primary and metastatic ET resistant BCs.

The role of G-protein-coupled membrane estrogen receptor in mouse Leydig cell function-in vivo and in vitro evaluation

In this study, G-coupled estrogen receptor (GPER) was inactivated, by treatment with antagonist (G-15), in testes of C57BL/6 mice: immature (3 weeks old), mature (3 months old) and aged (1.5 years old) (50 μg/kg bw), as well as MA-10 mouse Leydig cells (10 nM/24 h) alone or in combination with 17β-estradiol or antiestrogen (ICI 182,780). In G-15-treated mice, overgrowth of interstitial tissue was found in both mature and aged testes. Depending on age, differences in structure and distribution of various Leydig cell organelles were observed. Concomitantly, modulation of activity of the mitochondria and tubulin microfibers was revealed. Diverse and complex GPER regulation at the mRNA level and protein of estrogen signaling molecules (estrogen receptor α and β; ERα, ERβ and cytochrome P450 aromatase; P450arom) in G-15 Leydig cells was found in relation to age and the experimental system utilized (in vivo and in vitro). Changes in expression patterns of ERs and P450arom, as well as steroid secretion, reflected Leydig cell heterogeneity to estrogen regulation throughout male life including cell physiological status.We show, for the first time, GPER with ERs and P450arom work in tandem to maintain Leydig cell architecture and supervise its steroidogenic function by estrogen during male life. Full set of estrogen signaling molecules, with involvement of GPER, is crucial for proper Leydig cell function where each molecule acts in a specific and/or complementary manner. Further understanding of the mechanisms by which GPER controls Leydig cells with special regard to male age, cell of origin and experimental system used is critical for predicting and preventing testis steroidogenic disorders based on perturbations in estrogen signaling.

Put "gender glasses" on the effects of phenolic compounds on cardiovascular function and diseases

INTRODUCTION

The influence of sex and gender is particularly relevant in cardiovascular diseases (CVD) as well as in several aspects of drug pharmacodynamics and pharmacokinetics. Anatomical and physiological differences between the sexes may influence the activity of many drugs, including the possibility of their interaction with other drugs, bioactive compounds, foods and beverages. Phenolic compounds could interact with our organism at organ, cellular, and molecular levels triggering a preventive action against chronic diseases, including CVD.

RESULTS

This article will review the role of sex on the activity of these bioactive molecules, considering the existence of sex differences in oxidative stress. It describes the pharmacokinetics of phenolic compounds, their effects on vessels, on cardiovascular system, and during development, including the role of nuclear receptors and microbiota.

CONCLUSIONS

Although there is a large gap between the knowledge of the sex differences in the phenolic compounds' activity and safety, and the urgent need for more research, available data underlie the possibility that plant-derived phenolic compounds could differently influence the health of male and female subjects.

Nonylphenol and Octylphenol Differently Affect Cell Redox Balance by Modulating the Nitric Oxide Signaling

Nonylphenol (NP) and octylphenol (OP) are pervasive environmental contaminants belonging to the broader class of compounds known as alkylphenols, with potential human toxic effects. Classified as “xenoestrogens,” NP and OP are able to interfere with the cell endocrine physiology via a direct interaction with the estrogen receptors. Here, using HepG2 cells in culture, the changes of the cell redox balance and mitochondrial activity induced by OP and NP have been investigated at μM concentrations, largely below those provoking acute toxicity, as those typical of environmental contaminants. Following 24 h cell exposure to both OP and NP, ROS production appeared significantly increased (p ≤ 0.01), together with the production of higher NO oxides (p = 0.003) and peroxynitrated protein-derivatives (NP versus CTR, p = 0.003). The mitochondrial proton electrochemical potential gradient instead was decreased (p ≤ 0.05), as the oxygen consumption by complex IV, particularly following incubation with NP (NP versus CTR, p = 0.017). Consistently, the RT-PCR and Western blot analyses proved that the OP and NP can modulate to a different extent the expression of the inducible NOS (NP versus CTR, p ≤ 0.01) and the endothelial NOS (OP versus CTR, p ≤ 0.05), with a significant variation of the coupling efficiency of the latter (NP versus CTR, p ≤ 0.05), a finding that may provide a novel clue to understand the specific xenoestrogenic properties of OP and NP.

A high throughput method to study the physiology of E2:ERα signaling in breast cancer cells

17β-estradiol (E2) regulates diverse physiological effects including cell proliferation through the estrogen receptor α (ERα), which as a transcription factor drives gene transcription and as an extra-nuclear localized receptor triggers the membrane-dependent activation of diverse kinase cascades. E2 also modifies ERα intracellular levels via diverse intracellular mechanisms. In this way, the E2-acivated ERα integrates signaling cascades with the modulation of receptor intracellular concentration and with the induction of DNA synthesis and ultimately drives cell proliferation. In turn, E2 signaling deregulation can cause many diseases including breast cancer (BC). Recently, we performed a Western blotting (WB)-based screen to identify novel pathways affecting ERα intracellular levels and BC cell proliferation. However, because WB lacks high throughput potential, a high-content method to detect all aspects of E2:ERα signaling (nuclear and extra-nuclear receptor activity, ERα levels, E2-induced DNA synthesis) is desirable. Here, we set up a rapid way to measure E2:ERα signaling in 96-well plate format. To demonstrate its robustness, we also challenged 4OH-tamoxifen resistant (Tam-Res) BC cells with a library of anti-cancer drugs and identified methotrexate (MTX) as a molecule inducing ERα degradation and preventing BC cell proliferation. Overall, our research provides a high-content technique to study the physiology of E2:ERα signaling in cells and further suggests a possible anti-ERα and anti-proliferative use for MTX in Tam-Res BCs.