The estrogen receptor beta-isoform (ERbeta) of the human estrogen receptor modulates ERalpha transcriptional activity and is a key regulator of the cellular response to estrogens and antiestrogens

Manganese-induced Precocious Puberty Alters Mammary Epithelial Cell Proliferation in Female Rats

Precocious puberty (PP) is an established breast cancer risk factor. In the normal mammary gland, hormone receptor-positive (HR+) cells rarely proliferate. In breast cancer, proliferating epithelial cells are often HR+. It is not known if PP can modify this population of proliferating HR+ cells. Previously, we established a manganese-induced precocious puberty (MnPP) model to study the effects of PP on mammary gland development in female rats. Here, we characterized the distribution of HR+ proliferating mammary epithelial cells in prepubertal and adult rodents, in association with precocious puberty. Female rats were exposed daily to 10 mg/kg manganese chloride or saline (control) from postnatal day (PND) 12 to PND 30. Mammary glands were collected on PNDs 30 and 120, processed for western blot analysis and double immunofluorescence staining for proliferating cell nuclear antigen and progesterone receptor or estrogen receptor. MnPP increased the percentage of HR+ mammary epithelial cells coexpressing proliferating cell nuclear antigen relative to normally developed controls at PND 30. This correlated with increased expression of estrogen receptor-regulated proteins in MnPP mammary glands relative to controls at PND 30, including FOXA1, AREG, and c-Myc. Conversely, at PND 120 relative to PND 30, proliferating HR+ cells remained chronically elevated in MnPP mammary glands at PND 120, which coincided with decreased expression of cell-cycle regulator, p27, and increased expression of progesterone receptor-regulated markers, EREG and sp1. Collectively, these results suggest early puberty alters steroidal regulation of classic proliferative mechanisms in the prepubertal gland with increased prevalence of high-risk proliferating HR+ cells.

Research progress on estrogen and estrogen receptors in the occurrence and progression of autoimmune thyroid diseases

Autoimmune thyroid disease (AITD) is a category of disease related to sex differences, with a significantly higher incidence in women than in men. In addition to X chromosome inactivation abnormalities, Estrogen and estrogen receptors may lead to the sex differences in AITD. Estrogen, estrogen receptors and estrogen receptor-mediated signaling pathways can affect the number and function of immune cells and the function of the thyroid to promote the development of AITD. This article describes the role of estrogen in regulating the composition ratio and the function of immune cells and the role of estrogen in promoting thyroid cell proliferation and thyroxine-binding protein and thyroid antibody production; the role of estrogen in stimulating the hypothalamus-pituitary-thyroid gland axis; and the role of estrogen and the estrogen receptor in the progression of AITD. These roles offer a new perspective for understanding the pathological mechanism of AITD and provide new targets for future therapeutic strategies.

Interaction between Estrogen Receptors and p53: A Broader Role for Tamoxifen?

Tamoxifen is one of the most widely used anticancer drugs in the world. It is a safe drug with generally well-tolerated side effects and has been prescribed for the treatment of early-stage and advanced-stage or metastatic estrogen receptor α (ERα/ESR1)-positive breast cancer. Tamoxifen therapy also provides a 38% reduction of the risk of developing breast cancer in women at high risk. With the advent of newer medications targeting ERα-positive breast cancer, tamoxifen is now mainly used as adjuvant therapy for lower-risk premenopausal breast cancer and cancer prevention. It is widely accepted that tamoxifen as a selective estrogen receptor modulator exerts its therapeutic effect by competitively binding to ERα, leading to the recruitment of corepressors and inhibition of transcription of genes involved in the proliferation of breast cancer epithelium. As such, expression of ERα in breast tumors has been considered necessary for tumors to be responsive to tamoxifen therapy. However, ERα-independent effects of tamoxifen in various in vitro and in vivo contexts have been reported over the years. Importantly, the recent discovery that ERα and estrogen receptor β (ERβ/ESR2) can bind tumor suppressor protein p53 with functional consequences has provided new insights into the mechanisms underlying response to tamoxifen therapy and resistance. Furthermore, these findings have paved the way for broadening the use of tamoxifen by potentially repurposing it to treat triple negative (negative for ERα, human epidermal growth factor receptor 2, and progesterone receptor) breast cancer. Herein, we summarize these developments and discuss their mechanistic underpinnings and clinical implications.

The Hypothalamus and Pituitary Gland Regulate Reproduction and Are Involved in the Development of Polycystic Ovary Syndrome

BACKGROUND

Polycystic ovary syndrome (PCOS) is a complex condition with unclear mechanisms, posing a challenge for prevention and treatment of PCOS. The role of the hypothalamus and pituitary gland in regulating female reproduction is critical. Abnormalities in the hypothalamus and pituitary can impair reproductive function. It is important to study hypothalamic and pituitary changes in patients with PCOS.

SUMMARY

This article reviews articles on the hypothalamus and PCOS with the goal of summarizing what abnormalities of the hypothalamic-pituitary-ovarian axis are present in patients with PCOS and to clarify the pathogenesis of PCOS. We find that the mechanisms by which the hypothalamus and pituitary regulate reproduction in girls are complex and are associated with altered sex hormone levels, obesity, and insulin resistance. Different animal models of PCOS are characterized by different alterations in the hypothalamus and pituitary and respond differently to different treatments, which correspond to the complex pathogenesis of patients with PCOS.

KEY MESSAGES

Arcuate nucleus (ARC) is associated with luteinizing hormone (LH) surges. Suprachiasmatic nucleus, ARC, and RP3V are associated with LH surges. Animal models of PCOS have different characteristics.

A Dynamic Shift in Estrogen Receptor Expression During Granulosa Cell Differentiation in the Ovary

This study uncovers a dynamic shift in estrogen receptor expression during granulosa cell (GC) differentiation in the ovary, highlighting a transition from estrogen receptor alpha (ESR1) to estrogen receptor beta (ESR2). Using a transgenic mouse model with Esr1-iCre-mediated Esr2 deletion, we demonstrate that ESR2 expression is absent in GCs derived from ESR1-expressing ovarian surface epithelium (OSE) cells. Single-cell analysis of the OSE-GC lineage reveals a developmental trajectory from Esr1-expressing OSE cells to Foxl2-expressing pre-GCs, culminating in GCs exclusively expressing Esr2. Transcriptome analyses identified vasculature-derived TGFβ1 ligands as key regulators of this transition. Supporting this, TGFβ1 treatment of cultured embryonic ovaries reduced Esr1 expression while promoting Esr2 expression. This study underscores the capability of GCs to switch from ESR1 to ESR2 expression as a fundamental aspect of normal differentiation.

The Impact of Dietary Encapsulated Fennel Seed (Foeniculum vulgare Mill.) Essential Oil Inclusion Levels on Performance, Serum Hormone Profiles, and Expression of Reproductive Axis-Related Genes in the Early and Late Laying Phases of Hens

Fennel seed (Foeniculum vulgare Mill.) essential oil (FEO), which is rich in the phytoestrogenic compound trans-anethole, interacts with oestrogen receptors and influences molecular targets within cells and hormonal responses. This study examined the effect of dietary encapsulated FEO inclusion levels on performance, reproductive hormone profiles, and gene expression in laying hens during the early and late phases. The study was conducted in two independent trials, each involving 210 Atak-S laying hens that were randomly distributed into 3 experimental groups, each having 10 replicates with 7 hens. The dietary treatments included a basal diet without FEO (Control) and a basal diet supplemented with 175 (FEO175) or 350 mg (FEO350) of encapsulated FEO/kg for 12 weeks. The results showed that FEO350 treatment improved egg production, egg mass, and feed conversion ratio during both early and late phases (p < 0.05). Moreover, increasing FEO inclusion levels enhanced oestradiol, follicle-stimulating hormone, luteinizing hormone and progesterone concentrations in both early and late laying hens, reaching peak levels at FEO350 (p < 0.05). FEO supplementation upregulated the expression of oestrogen receptor 2 (ESR2) and follicle-stimulating hormone receptor (FSHR) (p < 0.05). Furthermore, FEO350 increased prolactin receptor (PRLR) expression during the early phase but decreased it during the late laying phase (p < 0.05). Positive correlations were observed between egg production and FSHR, ESR2 and steroidogenic acute regulatory protein (STAR) expression, with a negative correlation for PRLR (p < 0.05). In conclusion, 350 mg FEO/kg was found to be the most effective level for enhancing layer performance.

Cellular and molecular mechanisms of action of ovarian steroid hormones. I: Regulation of central nervous system function

The conventional way steroid hormones work through receptors inside cells is widely acknowledged. There are unanswered questions about what happens to the hormone in the end and why there isn't always a strong connection between how much tissue takes up and its biological effects through receptor binding. Steroid hormones can also have non-traditional effects that happen quickly but don't involve entering the cell. Several possible mechanisms for these non-traditional actions include (a) changes in membrane fluidity, (b) steroid hormones acting on receptors on the outer surface of cells, (c) steroid hormones regulating GABAA receptors on cell membranes, and (d) activation of steroid receptors by factors like EGF, IGF-1, and dopamine. Data also suggests that steroid hormones may be inserted into DNA through receptors, acting as transcription factors. These proposed new mechanisms of action should not be seen as challenging the conventional mechanism. Instead, they contribute to a more comprehensive understanding of how hormones work, allowing for rapid, short-term, and prolonged effects to meet the body's physiological needs.

Estrogen-dependent gene regulation: Molecular basis of TIMP-1 as a sex-specific biomarker for acute lung injury

Increased circulating tissue inhibitor of metalloproteinases-1 (TIMP-1) levels have been observed in patients with acute lung injury (ALI). However, the sex-specific regulation of TIMP-1 and the underlying molecular mechanisms have not been well elucidated. In this study, we found that plasma TIMP-1 levels were significantly higher in COVID-19 and H1N1 patients compared with those in healthy subjects (n = 25). TIMP-1 concentrations were significantly different between males and females in each disease group. Among female but not male patients, TIMP-1 levels significantly correlated with the PaO2/FiO2 ratio and hospital length of stay. Using the mouse model of ALI induced by the H1N1 virus, we found that TIMP-1 is strikingly induced in PDGFRα-positive cells in the murine lungs. Moreover, female mice showed a higher Timp-1 expression in the lungs on day 3 postinfection. Mechanistically, we observed that estrogen can upregulate TIMP-1 expression in lung fibroblasts, not epithelial cells. In addition, overexpression of estrogen receptor α (ERα) increased the TIMP-1 promoter activity. In summary, TIMP-1 is an estrogen-responsive gene, and its promoter activity is regulated by ERα. Circulating TIMP-1 may serve as a sex-specific marker, reflecting the severity and worst outcomes in female patients with SARS-CoV2- and IAV-related ALI.

Advances in immune regulation of the G protein-coupled estrogen receptor

Estrogen and related receptors have been shown to have a significant impact on human development, reproduction, metabolism and immune regulation and to play a critical role in tumor development and treatment. Traditionally, the nuclear estrogen receptors (nERs) ERα and ERβ have been thought to be involved in mediating the estrogenic effects. However, our group and others have previously demonstrated that the G protein-coupled estrogen receptor (GPER) is the third independent ER, and estrogen signaling mediated by GPER is known to play an important role in normal physiology and a variety of abnormal diseases. Interestingly, recent studies have progressively revealed GPER involvement in the maintenance of the normal immune system, abnormal immune diseases, and inflammatory lesions, which may be of significant clinical value primarily in the immunotherapy of tumors. In this article, we review current advances in GPER-related immunomodulators and provide a theoretical basis and potential clinical targets to ameliorate immune-related diseases and immunotherapy for tumors.

Estrogen Receptor Alpha Mutations, Truncations, Heterodimers, and Therapies

Annual breast cancer (BCa) deaths have declined since its apex in 1989 concomitant with widespread adoption of hormone therapies that target estrogen receptor alpha (ERα), the prominent nuclear receptor expressed in ∼80% of BCa. However, up to ∼50% of patients who are ER+ with high-risk disease experience post endocrine therapy relapse and metastasis to distant organs. The vast majority of BCa mortality occurs in this setting, highlighting the inadequacy of current therapies. Genomic abnormalities to ESR1, the gene encoding ERα, emerge under prolonged selective pressure to enable endocrine therapy resistance. These genetic lesions include focal gene amplifications, hotspot missense mutations in the ligand binding domain, truncations, fusions, and complex interactions with other nuclear receptors. Tumor cells utilize aberrant ERα activity to proliferate, spread, and evade therapy in BCa as well as other cancers. Cutting edge studies on ERα structural and transcriptional relationships are being harnessed to produce new therapies that have shown benefits in patients with ESR1 hotspot mutations. In this review we discuss the history of ERα, current research unlocking unknown aspects of ERα signaling including the structural basis for receptor antagonism, and future directions of ESR1 investigation. In addition, we discuss the development of endocrine therapies from their inception to present day and survey new avenues of drug development to improve pharmaceutical profiles, targeting, and efficacy.

The Role of Estrogen and Estrogen Receptors in Head and Neck Tumors

Head and neck squamous cell carcinoma (HNSCC) is the most common histological form of head and neck tumors (HNTs), which originate from the epithelium of the lips and oral cavity, pharynx, larynx, salivary glands, nasal cavity, and sinuses. The main risk factors include consumption of tobacco in all forms and alcohol, as well as infections with high-risk human papillomaviruses or the Epstein-Barr virus. Regardless of the etiological agent, the risk of developing different types of HNTs is from two to more than six times higher in males than in females. The reason for such disparities probably lies in a combination of both biological and psychosocial factors. Therefore, it is hypothesized that exposure to female sex hormones, primarily estrogen, provides women with protection against the formation and metastasis of HNTs. In this review, we synthesized available knowledge on the role of estrogen and estrogen receptors (ERs) in the development and progression of HNTs, with special emphasis on membrane ERs, which are much less studied. We can summarize that in addition to epidemiologic studies unequivocally pointing to the protective effect of estrogen in women, an increased expression of both nuclear ERs, ERα, and ERβ, and membrane ERs, ERα36, GPER1, and NaV1.2, was present in different types of HNSCC, for which anti-estrogens could be used as an effective therapeutic approach.

Molecular insights into the potential effects of selective estrogen receptor β agonists in Alzheimer's and Parkinson's diseases

Alzheimer's disease (AD) and Parkinson's disease (PD) are the most common neurodegenerative disorders. Pathologically, AD and PD are characterized by the accumulation of misfolded proteins. Hence, they are also called as proteinopathy diseases. Gender is considered as one of the risk factors in both diseases. Estrogens are widely accepted to be neuroprotective in several neurodegenerative disorders. Estrogens can be produced in the central nervous system, where they are called as neurosteroids. Estrogens mediate their neuroprotective action mainly through their actions on estrogen receptor alpha (ERα) and estrogen receptor beta (ERβ). However, ERα is mainly involved in the growth and development of the primary and secondary sexual organs in females. Hence, the activation of ERα is associated with undesired side effects such as gynecomastia and increase in the risk of breast cancer, thromboembolism, and feminization. Therefore, selective activation of ERβ is often considered to be safer. In this review, we explore the role of ERβ in regulating the expression and functions of AD- and PD-associated genes. Additionally, we discuss the association of these genes with the amyloid-beta peptide (Aβ) and α-synuclein mediated toxicity. Ultimately, we established a correlation between the importance of ERβ activation and the process underlying ERβ's neuroprotective mechanisms in AD and PD.

Estrogen receptor β affects hypoxia response in colorectal cancer cells

The occurrence of colorectal cancer (CRC) is inversely correlated with estrogen receptor beta (ERβ) presence. Additionally, multiple studies associate low ERβ expression with poorer overall survival of CRC patients. Molecular pathways involved in ERβ - related reduced tumorigenesis include enhanced apoptosis, decreased proliferation, or repression of oncogenes. Moreover, the development of solid tumors, such as CRC, is often associated with an increased tumor mass that results in decreased oxygen partial tension, known as hypoxia, clinically associated with decreased prognosis and therapeutic resistance. Our high-throughput study suggests that ERβ also represses a hypoxic response in CRC cells. We observed a significantly altered transcriptional profile in HCT116 ERβ overexpressing cells that was further stimulated by E2 treatment under hypoxic conditions. The achieved data for downregulation of VEGFA, PDGFA and ANGPTL4 were validated in a time course experiment in DLD-1 cells. In addition, using an ERβ construct with a mutated DNA binding domain we observed that the downregulation of selected genes is dependent on the direct binding of this receptor to regulatory region genes. In addition, we observed that ERβ may affect the expression of the main hypoxia regulator, HIF1A, at the transcriptional and translational levels. In summary, ERβ alters the hypoxic outcome in CRC cells.

Sex hormone signaling and regulation of immune function

Immune responses to antigens, including innocuous, self, tumor, microbial, and vaccine antigens, differ between males and females. The quest to uncover the mechanisms for biological sex differences in the immune system has intensified, with considerable literature pointing toward sex hormonal influences on immune cell function. Sex steroids, including estrogens, androgens, and progestins, have profound effects on immune function. As such, drastic changes in sex steroid concentrations that occur with aging (e.g., after puberty or during the menopause transition) or pregnancy impact immune responses and the pathogenesis of immune-related diseases. The effect of sex steroids on immunity involves both the concentration of the ligand and the density and distribution of genomic and nongenomic receptors that serve as transcriptional regulators of immune cellular responses to affect autoimmunity, allergy, infectious diseases, cancers, and responses to vaccines. The next frontier will be harnessing these effects of sex steroids to improve therapeutic outcomes.

Overexpression of BQ323636.1 contributes to anastrozole resistance in AR+ve/ER+ve breast cancer

Aromatase inhibitors (Ais) are used as adjuvant endocrine therapy for oestrogen receptor-positive (ER+ve) post-menopausal breast cancer patients. Ais, by inhibiting the enzyme aromatase, block the conversion of androgen to oestrogen, reducing oestrogen levels. Resistance to Ais limits their clinical utilisation. Here, we show that overexpression of BQ323636.1 (BQ), a novel splice variant of nuclear co-repressor NCOR2, is associated with resistance to the non-steroidal aromatase inhibitor anastrozole in ER+ve post-menopausal breast cancer. Mechanistic study indicates that BQ overexpression enhances androgen receptor (AR) activity and in the presence of anastrozole, causes hyper-activation of AR signalling, which unexpectedly enhanced cell proliferation, through increased expression of CDK2, CDK4, and CCNE1. BQ overexpression reverses the effect of anastrozole in ER+ve breast cancer in an AR-dependent manner, whilst co-treatment with the AR antagonist bicalutamide recovered its therapeutic effect both in vitro and in vivo. Thus, for BQ-overexpressing breast cancer, targeting AR can combat anastrozole resistance. Clinical study of 268 primary breast cancer samples of ER+ve patients who had been treated with non-steroidal Ais showed 32.5% (38/117) of cases with combined high nuclear expression of BQ and AR, which were found to be significantly associated with Ai resistance. Non-steroidal Ai-treated patients with high nuclear expression of both BQ and AR had poorer overall, disease-specific, and disease-free survival. These findings suggest the importance of assessing BQ and AR expression status in the primary ER+ve breast tumour prior to Ai treatment. This may save patients from inappropriate treatment and enable effective therapy to be given at an early stage. © 2023 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

The habitual characteristic of smart phone use under relevant cues among Chinese college students

Excessive smartphone use may be habitual behavior induced by cues associated with the phone. Habitual behavior occurs outside of awareness and is characterized by lack of control. It is not like problematic smartphone use (PSU) (Brand et al., 2016), which is used to either limit behavior or produce pleasure and relieve feelings of pain, stress, and failure despite significant harmful consequences. 62 college students participated in experiments to test the effects of visual cues and self-control, which are the important characteristic of habitual behavior in smartphone-related behavior. The results showed that a significantly larger amount of cue-related phone use behavior occurred in the setting where participants (a) had their smartphones in sight and (b) were given no instructions to exert self-control, compared to when neither of the two conditions was imposed. The habitual model is a useful framework for understanding PSU and can help people avoid it with less stress. The results provide substantial implications for reducing the frequency and duration of smartphone use among college populations.

The Role of NLRP3 in Regulation of Antimicrobial Peptides and Estrogen Signaling in UPEC-Infected Bladder Epithelial Cells

The NLRP3 inflammasome, estrogen and antimicrobial peptides have all been found to have a vital role in the protection of the bladder urothelium. However, the interdependence between these protective factors during a bladder infection is currently unknown. Our aim was to investigate the role of NLRP3 in the regulation of antimicrobial peptides and estrogen signaling in bladder epithelial cells during a UPEC infection. Human bladder epithelial cells and CRISPR/Cas9-generated NLRP3-deficient cells were stimulated with the UPEC strain CFT073 and estradiol. The gene and protein expression were evaluated with microarray, qRT-PCR, western blot and ELISA. Microarray results showed that the expression of most antimicrobial peptides was reduced in CFT073-infected NLRP3-deficient cells compared to Cas9 control cells. Conditioned medium from NLRP3-deficient cells also lost the ability to suppress CFT073 growth. Moreover, NLRP3-deficient cells had lower basal release of Beta-defensin-1, Beta-defensin-2 and RNase7. The ability of estradiol to induce an increased expression of antimicrobial peptides was also abrogated in NLRP3-deficient cells. The decreased antimicrobial peptide expression might be linked to the observed reduced expression and activity of estradiol receptor beta in NLRP3-deficient cells. This study suggests that NLRP3 may regulate the release and expression of antimicrobial peptides and affect estrogen signaling in bladder epithelial cells.

Alternative promoters and splicing create multiple functionally distinct isoforms of oestrogen receptor alpha in breast cancer and healthy tissues

BACKGROUND

Oestrogen receptor alpha (ER) is involved in cell growth and proliferation and functions as a transcription factor, a transcriptional coregulator, and in cytoplasmic signalling. It affects, for example, bone, endometrium, ovaries and mammary epithelium. It is a key biomarker in clinical management of breast cancer, where it is used as a prognostic and treatment-predictive factor, and a therapeutical target. Several ER isoforms have been described, but transcript annotation in public databases is incomplete and inconsistent, and functional differences are not well understood.

METHODS

We have analysed short- and long-read RNA sequencing data from breast tumours, breast cancer cell lines, and normal tissues to create a comprehensive annotation of ER transcripts and combined it with experimental studies of full-length protein and six alternative isoforms.

RESULTS

The isoforms have varying transcription factor activity, subcellular localisation, and response to the ER-targeting drugs tamoxifen and fulvestrant. Antibodies differ in ability to detect alternative isoforms, which raises concerns for the interpretation of ER-status in routine pathology.

CONCLUSIONS

Future work should investigate the effects of alternative isoforms on patient survival and therapy response. An accurate annotation of ER isoforms will aid in interpretation of clinical data and inform functional studies to improve our understanding of the ER in health and disease.

A New Culture Model for Enhancing Estrogen Responsiveness in HR+ Breast Cancer Cells through Medium Replacement: Presumed Involvement of Autocrine Factors in Estrogen Resistance

Hormone receptor-positive breast cancer (HR+ BC) cells depend on estrogen and its receptor, ER. Due to this dependence, endocrine therapy (ET) such as aromatase inhibitor (AI) treatment is now possible. However, ET resistance (ET-R) occurs frequently and is a priority in HR+ BC research. The effects of estrogen have typically been determined under a special culture condition, i.e., phenol red-free media supplemented with dextran-coated charcoal-stripped fetal bovine serum (CS-FBS). However, CS-FBS has some limitations, such as not being fully defined or ordinary. Therefore, we attempted to find new experimental conditions and related mechanisms to improve cellular estrogen responsiveness based on the standard culture medium supplemented with normal FBS and phenol red. The hypothesis of pleiotropic estrogen effects led to the discovery that T47D cells respond well to estrogen under low cell density and medium replacement. These conditions made ET less effective there. The fact that several BC cell culture supernatants reversed these findings implies that housekeeping autocrine factors regulate estrogen and ET responsiveness. Results reproduced in T47D subclone and MCF-7 cells highlight that these phenomena are general among HR+ BC cells. Our findings offer not only new insights into ET-R but also a new experimental model for future ET-R studies.

Protective Role of Kelulut Honey against Toxicity Effects of Polystyrene Microplastics on Morphology, Hormones, and Sex Steroid Receptor Expression in the Uterus of Rats

BACKGROUND

Microplastics (MPs) are an emerging global pollutant. Previous studies have revealed that chronic exposure to MPs can affect animal and human reproductive health, particularly by impairing the reproductive system's normal functions, which may increase the risk of infertility in both males and females. Kelulut honey (KH), an excellent source of antioxidants, has been used to counteract the disruptive effects of Polystyrene microplastics (PS-MPs) in the rat uterus. Thus, this study aimed to investigate the potential protective effects of Kelulut honey against PS-MPs-induced uterine toxicity in pubertal rats.

METHODS

Prepubertal female Sprague Dawley rats were divided into four groups (n = 8): (i) normal control group (NC: treated with deionized water), MPs-exposed group (M: exposed to PS-MPs at 2.5 mg/kg), (iii) Kelulut honey group (DM: pretreated with 1200 mg/kg of KH 30 minutes before they were administered with PS-MPs at 2.5 mg/kg), and (iv) Kelulut honey control group (DC: only treated with KH at 2.5 mg/kg). The rats were treated orally once daily for six consecutive weeks.

RESULTS

Uterine abnormalities in PS-MPs-exposed rats were significantly improved after concurrent treatment with Kelulut honey. Morphology improvement was observed and luminal epithelial cells seemed thicker with more goblet cells, glandular cells had a more regular and circular shape, stromal cell increased in size, interstitial gaps between stromal cells expanded, and the myometrium layer was thicker. Kelulut honey treatment also effectively normalized the suppressive effect of PS-MPs on the expression and distribution of sex steroid receptors (ERα and ERβ), as well as the level of serum gonadotropin (LH and FSH) and sex steroid (estradiol and progesterone) hormones.

CONCLUSION

Kelulut honey can protect the female reproductive system against the disruptive effects of PS-MPs. The phytochemical properties of Kelulut honey might be responsible for these beneficial benefits. However, future studies are warranted to identify the mechanisms involved.

Significant Association of Estrogen Receptor-β Isoforms and Coactivators in Breast Cancer Subtypes

Nuclear receptor coregulators are the principal regulators of Estrogen Receptor (ER)-mediated transcription. ERβ, an ER subtype first identified in 1996, is associated with poor outcomes in breast cancer (BCa) subtypes, and the coexpression of the ERβ1 isoform and AIB-1 and TIF-2 coactivators in BCa-associated myofibroblasts is associated with high-grade BCa. We aimed to identify the specific coactivators that are involved in the progression of ERβ-expressing BCa. ERβ isoforms, coactivators, and prognostic markers were tested using standard immunohistochemistry. AIB-1, TIF-2, NF-kB, p-c-Jun, and/or cyclin D1 were differentially correlated with ERβ isoform expression in the BCa subtypes and subgroups. The coexpression of the ERβ5 and/or ERβ1 isoforms and the coactivators were found to be correlated with a high expression of P53, Ki-67, and Her2/neu and large-sized and/or high-grade tumors in BCa. Our study supports the notion that ERβ isoforms and coactivators seemingly coregulate the proliferation and progression of BCa and may provide insight into the potential therapeutic uses of the coactivators in BCa.

Estrogen Receptor Signaling in the Immune System

The immune system functions in a sexually dimorphic manner, with females exhibiting more robust immune responses than males. However, how female sex hormones affect immune function in normal homeostasis and in autoimmunity is poorly understood. In this review, we discuss how estrogens affect innate and adaptive immune cell activity and how dysregulation of estrogen signaling underlies the pathobiology of some autoimmune diseases and cancers. The potential roles of the major circulating estrogens, and each of the 3 estrogen receptors (ERα, ERβ, and G-protein coupled receptor) in the regulation of the activity of different immune cells are considered. This provides the framework for a discussion of the impact of ER modulators (aromatase inhibitors, selective estrogen receptor modulators, and selective estrogen receptor downregulators) on immunity. Synthesis of this information is timely given the considerable interest of late in defining the mechanistic basis of sex-biased responses/outcomes in patients with different cancers treated with immune checkpoint blockade. It will also be instructive with respect to the further development of ER modulators that modulate immunity in a therapeutically useful manner.

Microplastic in northern anchovies (Engraulis mordax) and common murres (Uria aalge) from the Monterey Bay, California USA - Insights into prevalence, composition, and estrogenic activity

Microplastic (particle size <5 mm) is considered an emerging threat to the marine environment, yet data are limited for coastal ecosystems. To provide information related to microplastic in a coastal system, we used alkaline tissue digestion and Raman spectroscopy to quantify the prevalence and composition (e.g. fiber, fragment, foam, etc.) of anthropogenic microparticles in the digestive tracts of northern anchovies (Engraulis mordax, anchovy, n = 24), and common murres (Uria aalge, murre, n = 19) from the Monterey Bay, California USA. We also determined microplastic prevalence and composition in seawater (n = 12 17-h sampling periods representing ∼46,000 L sampled) from two Monterey Bay intake systems (Moss Landing, CA and Santa Cruz, CA USA). Microparticles recovered from murre digestive tracts were assessed for estrogenic activity using an in-vitro estrogen receptor activation assay. Suspected anthropogenic microparticles based on visual characteristics were recovered from all sample types with ∼2 particles per 1000 L from the seawater sampling periods, 58% prevalence in anchovies, and 100% prevalence in murres. Across samples of seawater, anchovies, and murres, the most abundant microparticle type found were fibers (78%), followed by fragments (13%), foam (6%), film (2%), and beads (1%). Raman spectroscopy identified 57% of microparticles (excluding dye-prominent and unknown) as plastic (synthetic, semi-synthetic, or blends). Almost one quarter (23%) of the murre digestive tracts contained microparticles that exhibited estrogenic activity. Our study describes the widespread occurrence, composition, and potential estrogenic activity of microplastic in the Monterey Bay and provides important information to aid in the understanding of microplastic contamination in coastal systems.

AKTIP loss is enriched in ERα-positive breast cancer for tumorigenesis and confers endocrine resistance

Recurrent deletion of 16q12.2 is observed in luminal breast cancer, yet the causal genomic alterations in this region are largely unknown. In this study, we identify that loss of AKTIP, which is located on 16q12.2, drives tumorigenesis of estrogen receptor alpha (ERα)-positive, but not ERα-negative, breast cancer cells and is associated with poor prognosis of patients with ERα-positive breast cancer. Intriguingly, AKTIP-depleted tumors have increased ERα protein level and activity. Cullin-associated and neddylation-dissociated protein 1 (CAND1), which regulates the cullin-RING E3 ubiquitin ligases, protects ERα from cullin 2-dependent proteasomal degradation. Apart from ERα signaling, AKTIP loss triggers JAK2-STAT3 activation, which provides an alternative survival signal when ERα is inhibited. AKTIP-depleted MCF7 cells and ERα-positive patient-derived organoids are more resistant to ERα antagonists. Importantly, the resistance can be overcome by co-inhibition of JAK2/STAT3. Together, our results highlight the subtype-specific functional consequences of AKTIP loss and provide a mechanistic explanation for the enriched AKTIP copy-number loss in ERα-positive breast cancer.

In vivo arterial stiffness, but not isolated artery endothelial function, varies with the mouse estrous cycle

With the increasing appreciation for sex as a biological variable and the inclusion of female mice in research, it is important to understand the influence of the estrous cycle on physiological function. Sex hormones are known to modulate vascular function, but the effects of the mouse estrous cycle phase on arterial stiffness, endothelial function, and arterial estrogen receptor expression remain unknown. In 23 female C57BL/6 mice (6 mo of age), we determined the estrous cycle stage via vaginal cytology and plasma hormone concentrations. Aortic stiffness, assessed by pulse wave velocity, was lower during the estrus phase compared with diestrus. In ex vivo assessment of isolated pressurized mesenteric and posterior cerebral arteries, the responses to acetylcholine, insulin, and sodium nitroprusside, as well as nitric oxide-mediated dilation, were not different between estrous cycle phases. In the aorta, expression of phosphorylated estrogen receptor-α was higher for mice in estrus compared with mice in proestrus. In the cerebral arteries, gene expression for estrogen receptor-β (Esr2) was lowest for mice in estrus compared with diestrus and proestrus. These results demonstrate that the estrus phase is associated with lower in vivo large artery stiffness in mice. In contrast, ex vivo resistance artery endothelial function is not different between estrous cycle phases. Estrogen receptor expression is modulated by the estrus cycle in an artery-dependent manner. These results suggest that the estrous cycle phase should be considered when measuring in vivo arterial stiffness in young female mice.NEW & NOTEWORTHY To design rigorous vascular research studies using young female rodents, the influence of the estrous cycle on vascular function must be known. We found that in vivo aortic stiffness was lower during estrus compared with the diestrus phase in female mice. In contrast, ex vivo mesenteric and cerebral artery endothelial function did not differ between estrous cycle stages. These results suggest that the estrous cycle stage should be accounted for when measuring in vivo arterial stiffness.

The AF-2 cofactor binding region is key for the selective SUMOylation of estrogen receptor alpha by antiestrogens

Antiestrogens (AEs) are used to treat all stages of estrogen receptor (ER)-positive breast cancer. Selective estrogen receptor modulators such as tamoxifen have tissue-specific partial agonist activity, while selective estrogen receptor downregulators such as fulvestrant (ICI182,780) display a more complete antiestrogenic profile. We have previously observed that fulvestrant-induced ERα SUMOylation contributes to transcriptional suppression, but whether this effect is seen with other AEs and is specific to ERα is unclear. Here we show that several AEs induce SUMOylation of ERα, but not ERβ, at different levels. Swapping domains between ERα and ERβ indicates that the ERα identity of the ligand-binding domain helices 3 and 4 (H3-H4 region), which contribute to the static part of the activation function-2 (AF-2) cofactor binding groove, is sufficient to confer fulvestrant-induced SUMOylation to ERβ. This region does not contain lysine residues unique to ERα, suggesting that ERα-specific residues in H3-H4 determine the capacity of the AE-bound ERα ligand-binding domain to recruit the SUMOylation machinery. We also show that the SUMO E3 ligase protein inhibitor of activated STAT 1 increases SUMOylation of ERα and of ERβ containing the H3-H4 region of ERα, but not of ERβ. Together, these results shed new light on the molecular basis for the differential capacity of selective estrogen receptor modulators and selective estrogen receptor downregulators to suppress transcription by ERα.

The influence of ESR1 polymorphisms on selected hormonal, metabolic and mineral balance markers in women with hyperandrogenism

Hyperandrogenism is the most common endocrine disorder in women, characterized by an imbalance in normal estrogen and androgen levels in the blood. Androgens influence bone mineral density, body mass composition, muscle mass, mental state, and the regulation of sexual function.. The aim of the study was to assess the effect of estrogen receptor α gene (ESR1) polymorphisms on selected markers of bone metabolism and hormonal parameters in women with hyperandrogenism. The study group included 80 young women with hyperandrogenism who underwent measurements of bone mineral density (BMD), and determination of hormonal and metabolic parameters. Enzyme immunoassays were used to measure leptin, sRANKL (soluble receptor activator of nuclear factor-kB ligand), osteoprotegerin and 25-OH vitamin D total levels. An analysis of ESR1 gene polymorphisms was performed using the real-time PCR method. A relationship was demonstrated between the concentration of free estradiol (FEI) and the concentration of 17-OH-progesterone, and the ESR1 gene polymorphisms: rs3020314 (p = 0.031, p = 0.026 respectively) and rs1884051 (p = 0.033, p = 0.026 respectively). In conclusion, the ESR gene polymorphisms may be associated with hormonal disturbances in the concentration of estrogens and androgens, in hyperandrogenism in young women which may indirectly affect bone mineral density. However, no statistically significant relationships between the studied polymorphisms and the selected parameters of mineral metabolism have been demonstrated..

Photoswitchable Diazocine-Based Estrogen Receptor Agonists: Stabilization of the Active Form inside the Receptor

Photopharmacology is an emerging approach in drug design and pharmacological therapy. Light is used to switch a pharmacophore between a biologically inactive and an active isomer with high spatiotemporal resolution at the site of illness, thus potentially avoiding side effects in neighboring healthy tissue. The most frequently used strategy to design a photoswitchable drug is to replace a suitable functional group in a known bioactive molecule with azobenzene. Our strategy is different in that the photoswitch moiety is closer to the drug's scaffold. Docking studies reveal a very high structural similarity of natural 17β-estradiol and the E isomers of dihydroxy diazocines, but not their Z isomers, respectively. Seven dihydroxy diazocines were synthesized and subjected to a biological estrogen reporter gene assay. Four derivatives exhibit distinct estrogenic activity after irradiation with violet light, which can be shut off with green light. Most remarkably, the photogenerated, active E form of one of the active compounds isomerizes back to the inactive Z form with a half-life of merely several milliseconds in water, but nevertheless is active for more than 3 h in the presence of the estrogen receptor. The results suggest a significant local impact of the ligand-receptor complex toward back-isomerization. Thus, drugs that are active when bound but lose their activity immediately after leaving the receptor could be of great pharmacological value because they strongly increase target specificity. Moreover, the drugs are released into the environment in their inactive form. The latter argument is particularly important for drugs that act as endocrine disruptors.

An approach to uncover the relationship between 17b-estradiol and ESR1/ESR2 ratio in the regulation of canine corpus luteum

The canine corpus luteum (CL) is able to synthetise, activate and deactivate 17b-estradiol (E2) and also expresses nuclear estrogen receptors in a time-dependent manner during diestrus. Nevertheless, we are still missing a better comprehension of E2 functions in the canine CL, especially regarding the specific roles of estrogen receptor alpha (ERa) and ERb, encoded by ESR1 and 2, respectively. For that purpose, we analyzed transcriptomic data of canine non-pregnant CL collected on days 10, 20, 30, 40, 50 and 60 of diestrus and searched for differentially expressed genes (DEG) containing predicted transcription factor binding sites (TFBS) for ESR1 or ESR2. Based on biological functions of DEG presenting TFBS, expression of select transcripts and corresponding proteins was assessed. Additionally, luteal cells were collected across specific time points during diestrus and specificity of E2 responses was tested using ERa and/or ERb inhibitors. Bioinformatic analyses revealed 517 DEGs containing TFBS, from which 67 for both receptors. In general, abundance of predicted ESR1 targets was greater in the beginning, while abundance of ESR2 targets was greater in the end of diestrus. ESR1/ESR2 ratio shifted from an increasing to a decreasing pattern from day 30 to 40 post ovulation. Specific receptor inhibition suggested an ERa-mediated positive regulation of CL function at the beginning of diestrus and an ERb-mediated effect contributing to luteal regression. In conclusion, our data points toward a broad spectrum of action of E2 and its nuclear receptors, which can also act as transcription factors for other genes regulating canine CL function.

Hypothalamic Expression of Estrogen Receptor Isoforms Underlies Estradiol Control of Luteinizing Hormone in Female Rats

Luteinizing hormone (LH) secretion during the ovarian cycle is governed by fluctuations in circulating estradiol (E2) that oppositely regulate kisspeptin neurons in the anteroventral periventricular nucleus (AVPV) and arcuate nucleus (ARC) of the hypothalamus. However, how these effects are orchestrated to achieve fertility is unknown. Here, we have tested the hypothesis that AVPV and ARC neurons have different sensitivities to E2 to coordinate changes in LH secretion. Cycling and ovariectomized rats with low and high E2 levels were used. As an index of E2 responsiveness, progesterone receptor (PR) was expressed only in the AVPV of rats with high E2, showing the preovulatory LH surge. On the other hand, kisspeptin neurons in the ARC responded to low E2 levels sufficient to suppress LH release. Notably, the Esr1/Esr2 ratio of gene expression was higher in the ARC than AVPV, regardless of E2 levels. Accordingly, the selective pharmacological activation of estrogen receptor α (ERα) required lower doses to induce PR in the ARC. The activation of ERβ, in turn, amplified E2-induced PR expression in the AVPV and the LH surge. Thus, ARC and AVPV neurons are differently responsive to E2. Lower E2 levels activate ERα in the ARC, whereas ERβ potentiates the E2 positive feedback in the AVPV, which appears related to the differential Esr1/Esr2 ratio in these 2 brain areas. Our findings provide evidence that the distinct expression of ER isoforms in the AVPV and ARC plays a key role in the control of periodic secretion of LH required for fertility in females.

Molecular Mechanism of Equine Endometrosis: The NF-κB-Dependent Pathway Underlies the Ovarian Steroid Receptors’ Dysfunction

Endometrosis is a frequently occurring disease decreasing mares’ fertility. Thus, it is an important disease of the endometrium associated with epithelial and stromal cell alterations, endometrium gland degeneration and periglandular fibrosis. Multiple degenerative changes are found in uterine mucosa, the endometrium. However, their pathogenesis is not well known. It is thought that nuclear factor-κB (NF-κB), a cell metabolism regulator, and its activation pathways take part in it. The transcription of the profibrotic pathway genes of the NF-κB in fibrotic endometria differed between the follicular (FLP) and mid-luteal (MLP) phases of the estrous cycle, as well as with fibrosis progression. This study aimed to investigate the transcription of genes of estrogen (ESR1, ESR2) and progesterone receptors (PGR) in equine endometria to find relationships between the endocrine environment, NF-κB-pathway, and fibrosis. Endometrial samples (n = 100), collected in FLP or MLP, were classified histologically, and examined using quantitative PCR. The phase of the cycle was determined through the evaluation of ovarian structures and hormone levels (estradiol, progesterone) in serum. The transcription of ESR1, ESR2, and PGR decreased with the severity of endometrial fibrosis and degeneration of the endometrium. Moreover, differences in the transcription of ESR1, ESR2, and PGR were noted between FLP and MLP in the specific categories and histopathological type of equine endometrosis. In FLP and MLP, specific moderate and strong correlations between ESR1, ESR2, PGR and genes of the NF-κB pathway were evidenced. The transcription of endometrial steroid receptors can be subjected to dysregulation with the degree of equine endometrosis, especially in both destructive types of endometrosis, and mediated by the canonical NF-κB pathway depending on the estrous cycle phase.

Assessing Marine Endocrine-Disrupting Chemicals in the Critically Endangered California Condor: Implications for Reintroduction to Coastal Environments

Coastal reintroduction sites for California condors (Gymnogyps californianus) can lead to elevated halogenated organic compound (HOC) exposure and potential health impacts due to the consumption of scavenged marine mammals. Using nontargeted analysis based on comprehensive two-dimensional gas chromatography coupled to time-of-flight mass spectrometry (GC×GC/TOF-MS), we compared HOC profiles of plasma from inland and coastal scavenging California condors from the state of California (CA), and marine mammal blubber from CA and the Gulf of California off Baja California (BC), Mexico. We detected more HOCs in coastal condors (32 ± 5, mean number of HOCs ± SD, n = 7) than in inland condors (8 ± 1, n = 10) and in CA marine mammals (136 ± 87, n = 25) than in BC marine mammals (55 ± 46, n = 8). ∑DDT-related compounds, ∑PCBs, and total tris(chlorophenyl)methane (∑TCPM) were, respectively, ∼7, ∼3.5, and ∼148 times more abundant in CA than in BC marine mammals. The endocrine-disrupting potential of selected polychlorinated biphenyls (PCB) congeners, TCPM, and TCPMOH was determined by in vitro California condor estrogen receptor (ER) activation. The higher levels of HOCs in coastal condors compared to those in inland condors and lower levels of HOC contamination in Baja California marine mammals compared to those from the state of California are factors to consider in condor reintroduction efforts.

Tamoxifen administration alters gastrointestinal motility in mice

BACKGROUND

Tamoxifen is widely used for Cre-estrogen receptor-mediated genomic recombination in transgenic mouse models to mark cells for lineage tracing and to study gene function. However, recent studies have highlighted off-target effects of tamoxifen in various tissues and cell types when used for induction of Cre recombination. Despite the widespread use of these transgenic Cre models to assess gastrointestinal (GI) function, the effect of tamoxifen exposure on GI motility has not been described.

METHODS

We examined the effects of tamoxifen on GI motility by measuring total GI transit, gastric emptying, small intestinal transit, and colonic contractility in wild-type adult mice.

KEY RESULTS

We observed a significant delay in total GI transit in tamoxifen-treated mice, with unaltered gastric emptying, accelerated small intestinal transit, and abnormal colonic motility.

CONCLUSION

Our findings highlight the importance of considering GI motility alterations induced by tamoxifen when designing protocols that utilize tamoxifen as a Cre-driver for studying GI function.

ERβ Isoforms Have Differential Clinical Significance in Breast Cancer Subtypes and Subgroups

ERβ, an ER subtype first identified in 1996, is highly expressed in different types of BCa including ERα-negative BCa and TNBC. Many studies on ERβ expression investigated mostly on ERβ1 protein expression in ERα-positive and ERα-negative BCa combined. The results are conflicting. This may be due to the complexity of ERβ isoforms, subject heterogeneity, and various study designs targeting different ERβ isoforms and either ERβ protein or mRNA expression, as well as to the lack of a standardized testing protocol. Herein, we simultaneously investigated both mRNA and protein expression of ERβ isoforms 1, 2, and 5 in different BCa subtypes and clinical characteristics. Patient samples (138) and breast cancer cell lines (BCC) reflecting different types of BCa were tested for ERα and ERβ mRNA expression using quantitative real-time PCR, as well as for protein expression of ERα, ERβ1, ERβ2, and ERβ5 isoforms, PR, HER2/neu, Ki-67, CK 5/6, and p53 using immunohistochemistry. Associations of ERβ isoform expression with clinical characteristics and overall survival (OS) were analyzed. ERβ1, 2, and 5 isoforms are differentially expressed in different BCa subtypes including ERα-negative and TNBC. Each ERβ isoform seemingly plays a distinct role and is associated with clinical tumor characteristics and patient outcomes. ERβ isoform expression is significantly associated with >15% Ki-67 positivity and poor prognostic markers, and it predicts poorer OS, mostly in the subgroups. High ERβ2 and 5 isoform expression in ERα-negative BCa and TNBC is predictive of poor OS. Further investigation of ERβ isoforms in a larger cohort of BCa subgroups is needed to evaluate the role of ERβ for the potential usefulness of ERβ as a prognostic and predictive marker and for therapeutic use. The inconsistent outcomes of ERβ isoform mRNA or protein expression in many studies suggest that the standardization of ERβ testing would facilitate the use of ERβ in a clinical setting.

A human kinase yeast array for the identification of kinases modulating phosphorylation-dependent protein-protein interactions

Protein kinases play an important role in cellular signaling pathways and their dysregulation leads to multiple diseases, making kinases prime drug targets. While more than 500 human protein kinases are known to collectively mediate phosphorylation of over 290,000 S/T/Y sites, the activities have been characterized only for a minor, intensively studied subset. To systematically address this discrepancy, we developed a human kinase array in Saccharomyces cerevisiae as a simple readout tool to systematically assess kinase activities. For this array, we expressed 266 human kinases in four different S. cerevisiae strains and profiled ectopic growth as a proxy for kinase activity across 33 conditions. More than half of the kinases showed an activity-dependent phenotype across many conditions and in more than one strain. We then employed the kinase array to identify the kinase(s) that can modulate protein-protein interactions (PPIs). Two characterized, phosphorylation-dependent PPIs with unknown kinase-substrate relationships were analyzed in a phospho-yeast two-hybrid assay. CK2α1 and SGK2 kinases can abrogate the interaction between the spliceosomal proteins AAR2 and PRPF8, and NEK6 kinase was found to mediate the estrogen receptor (ERα) interaction with 14-3-3 proteins. The human kinase yeast array can thus be used for a variety of kinase activity-dependent readouts.

Estrogen Receptors-Mediated Apoptosis in Hormone-Dependent Cancers

It is known that estrogen stimulates growth and inhibits apoptosis through estrogen receptor(ER)-mediated mechanisms in many cancer cell types. Interestingly, there is strong evidence that estrogens can also induce apoptosis, activating different ER isoforms in cancer cells. It has been observed that E2/ERα complex activates multiple pathways involved in both cell cycle progression and apoptotic cascade prevention, while E2/ERβ complex in many cases directs the cells to apoptosis. However, the exact mechanism of estrogen-induced tumor regression is not completely known. Nevertheless, ERs expression levels of specific splice variants and their cellular localization differentially affect outcome of estrogen-dependent tumors. The goal of this review is to provide a general overview of current knowledge on ERs-mediated apoptosis that occurs in main hormone dependent-cancers. Understanding the molecular mechanisms underlying the induction of ER-mediated cell death will be useful for the development of specific ligands capable of triggering apoptosis to counteract estrogen-dependent tumor growth.

Overexpression of BQ323636.1 Modulated AR/IL-8/CXCR1 Axis to Confer Tamoxifen Resistance in ER-Positive Breast Cancer

NCOR2 is a co-repressor for estrogen receptor (ER) and androgen receptor (AR). Our group previously identified a novel splice variant of NCOR2, BQ323636.1 (BQ), that mediates tamoxifen resistance via interference of NCOR2 repression on ER. Luciferase reporter assay showed BQ overexpression could enhance the transcriptional activity of androgen response element (ARE). We proposed that BQ employs both AR and ER to confer tamoxifen resistance. Through in silico analysis, we identified interleukin-8 (IL-8) as the sole ERE and ARE containing gene responsiveness to ER and AR activation. We confirmed that BQ overexpression enhanced the expression of IL-8 in ER+ve breast cancer cells, and AR inhibition reduced IL-8 expression in the BQ overexpressing cell lines, suggesting that AR was involved in the modulation of IL-8 expression by BQ. Moreover, we demonstrated that IL-8 could activate both AKT and ERK1/2 via CXCR1 to confer tamoxifen resistance. Targeting CXCR1/2 by a small inhibitor repertaxin reversed tamoxifen resistance of BQ overexpressing breast cancer cells in vitro and in vivo. In conclusion, BQ overexpression in ER+ve breast cancer can enhance IL-8 mediated signaling to modulate tamoxifen resistance. Targeting IL-8 signaling is a promising approach to overcome tamoxifen resistance in ER+ve breast cancer.

Estradiol Signaling at the Heart of Folliculogenesis: Its Potential Deregulation in Human Ovarian Pathologies

Estradiol (E2) is a major hormone controlling women fertility, in particular folliculogenesis. This steroid, which is locally produced by granulosa cells (GC) within ovarian follicles, controls the development and selection of dominant preovulatory follicles. E2 effects rely on a complex set of nuclear and extra-nuclear signal transduction pathways principally triggered by its nuclear receptors, ERα and ERβ. These transcription factors are differentially expressed within follicles, with ERβ being the predominant ER in GC. Several ERβ splice isoforms have been identified and display specific structural features, which greatly complicates the nature of ERβ-mediated E2 signaling. This review aims at providing a concise overview of the main actions of E2 during follicular growth, maturation, and selection in human. It also describes the current understanding of the various roles of ERβ splice isoforms, especially their influence on cell fate. We finally discuss how E2 signaling deregulation could participate in two ovarian pathogeneses characterized by either a follicular arrest, as in polycystic ovary syndrome, or an excess of GC survival and proliferation, leading to granulosa cell tumors. This review emphasizes the need for further research to better understand the molecular basis of E2 signaling throughout folliculogenesis and to improve the efficiency of ovarian-related disease therapies.

Estrogen Receptor Bio-Activities Determine Clinical Endocrine Treatment Options in Estrogen Receptor-Positive Breast Cancer

In estrogen receptor positive (ER+) breast cancer therapy, estrogen receptors (ERs) are the major targeting molecules. ER-targeted therapy has provided clinical benefits for approximately 70% of all breast cancer patients through targeting the ERα subtype. In recent years, mechanisms underlying breast cancer occurrence and progression have been extensively studied and largely clarified. The PI3K/AKT/mTOR pathway, microRNA regulation, and other ER downstream signaling pathways are found to be the effective therapeutic targets in ER+ BC therapy. A number of the ER+ (ER+) breast cancer biomarkers have been established for diagnosis and prognosis. The ESR1 gene mutations that lead to endocrine therapy resistance in ER+ breast cancer had been identified. Mutations in the ligand-binding domain of ERα which encoded by ESR1 gene occur in most cases. The targeted drugs combined with endocrine therapy have been developed to improve the therapeutic efficacy of ER+ breast cancer, particularly the endocrine therapy resistance ER+ breast cancer. The combination therapy has been demonstrated to be superior to monotherapy in overall clinical evaluation. In this review, we focus on recent progress in studies on ERs and related clinical applications for targeted therapy and provide a perspective view for therapy of ER+ breast cancer.

Estrogen Receptor β Expression and Its Clinical Implication in Breast Cancers: Favorable or Unfavorable?

There are two estrogen receptor (ER) genes (ESR1/ERα and ESR2/ERβ) in humans. Of those. ERβ, the second ER isotype identified in 1996, is differentially expressed in different phenotypes and molecular subtypes of breast cancer (BCa), and is highly expressed in ERα-negative BCa and triple-negative BCa (TNBC). This review summarizes the potential clinical relevance of ERβ in BCa and the challenges associated with studies on the role of ERβ in BCa. The experimental and clinical studies evaluating clinical outcomes and associations with clinical characteristics and responses to endocrine therapy on targeting ERβ reviewed herein indicate that ERβ is a clinically important biomarker in BCa. The reviewed studies also suggest that each ERβ isoform has a distinct role in BCa subtypes and the potential of novel- targeted therapies in BCa, especially ERα-negative BCa and TNBC. However, the findings of many studies on ERβ are inconsistent, and the exact role of ERβ in BCa remains elusive; this may potentially be attributed to the complexity of ERβ isoforms, but also to the lack of standardized testing protocol. Thus, successful clinical application of ERβ requires the development of standardized, reproducible, and objective measurement methods for ERβ that can be widely and routinely applied in clinical setting.

Natural and Synthetic Estrogens in Chronic Inflammation and Breast Cancer

The oncogenic role of estrogen receptor (ER) signaling in breast cancer has long been established. Interaction of estrogen with estrogen receptor (ER) in the nucleus activates genomic pathways of estrogen signaling. In contrast, estrogen interaction with the cell membrane-bound G-protein-coupled estrogen receptor (GPER) activates the rapid receptor-mediated signaling transduction cascades. Aberrant estrogen signaling enhances mammary epithelial cell proliferation, survival, and angiogenesis, hence is an important step towards breast cancer initiation and progression. Meanwhile, a growing number of studies also provide evidence for estrogen's pro- or anti-inflammatory roles. As other articles in this issue cover classic ER and GPER signaling mediated by estrogen, this review will discuss the crucial mechanisms by which estrogen signaling influences chronic inflammation and how that is involved in breast cancer. Xenoestrogens acquired from plant diet or exposure to industrial products constantly interact with and alter innate estrogen signaling at various levels. As such, they can modulate chronic inflammation and breast cancer development. Natural xenoestrogens generally have anti-inflammatory properties, which is consistent with their chemoprotective role in breast cancer. In contrast, synthetic xenoestrogens are proinflammatory and carcinogenic compounds that can increase the risk of breast cancer. This article also highlights important xenoestrogens with a particular focus on their role in inflammation and breast cancer. Improved understanding of the complex relationship between estrogens, inflammation, and breast cancer will guide clinical research on agents that could advance breast cancer prevention and therapy.

Polymorphism analysis and expression profile of the estrogen receptor 2 gene in Leizhou black duck

Our previous study on the ovarian transcriptomic analysis in Leizhou black duck revealed that the ESR2 gene was involved in hormone regulation in reproduction and the estrogen signaling pathway related to reproductive performance was enriched. This suggested that ESR2 may have a functional role in the reproductive performance of the Leizhou black duck. Thus, this study aimed at evaluating the polymorphism of the ESR2 gene and its association with egg-laying traits and the distribution pattern of ESR2 mRNA in laying and non-laying Leizhou black ducks. In this study, genomic DNA was extracted from blood samples of 101 Leizhou black ducks to identify single nucleotide polymorphisms (SNPs) of the ESR2 gene to elucidate molecular markers highly associated with egg-laying traits. Four each of laying and non-laying Leizhou black ducks were selected to collect different tissues to analyze the ESR2 gene expression. A total of 23 SNPs were identified and association analysis of the single SNP sites showed that SNPs g.56805646 T>C and exon 3-20G>A were significantly (P < 0.05) associated with egg weight. Ducks with CT and AG genotypes had significantly higher (P < 0.05) egg weights than their respective other genotypes. Haplotype association analysis of g.56805646 T>C and exon 3-20G>A showed that the haplotypes were significantly associated with egg weight. Higher egg weight was seen in individuals with H3H4 haplotypes. In the hypothalamus-pituitary-gonadal (HPG) axis, the results of qRT/PCR showed that ESR2 mRNA was significantly (P < 0.05) expressed in the ovaries of both duck groups than in the hypothalamus and pituitary. In the oviduct, ESR2 was significantly (P < 0.05) higher in the infundibulum and magnum of laying and non-laying ducks respectively. This study provides a molecular marker for selecting Leizhou black ducks for egg production. In addition, it offers theoretical knowledge for studying the related biological functions of the ESR2 gene at the cellular level.

The Effects of Osteoporotic and Non-osteoporotic Medications on Fracture Risk and Bone Mineral Density

Osteoporosis is a highly prevalent bone disease affecting more than 37.5 million individuals in the European Union (EU) and the  United States of America (USA). It is characterized by low bone mineral density (BMD), impaired bone quality, and loss of structural and biomechanical properties, resulting in reduced bone strength. An increase in morbidity and mortality is seen in patients with osteoporosis, caused by the approximately 3.5 million new osteoporotic fractures occurring every year in the EU. Currently, different medications are available for the treatment of osteoporosis, including anti-resorptive and osteoanabolic medications. Bisphosphonates, which belong to the anti-resorptive medications, are the standard treatment for osteoporosis based on their positive effects on bone, long-term experience, and low costs. However, not only medications used for the treatment of osteoporosis can affect bone: several other medications are suggested to have an effect on bone as well, especially on fracture risk and BMD. Knowledge about the positive and negative effects of different medications on both fracture risk and BMD is important, as it can contribute to an improvement in osteoporosis prevention and treatment in general, and, even more importantly, to the individual's health. In this review, we therefore discuss the effects of both osteoporotic and non-osteoporotic medications on fracture risk and BMD. In addition, we discuss the underlying mechanisms of action.

Estrogen Receptor β as a Possible Double-Edged Sword Molecule in Breast Cancer: A Mechanism of Alteration of Its Role by Exposure to Endocrine-Disrupting Chemicals

Estrogen is essential for the growth and development of mammary glands and its signaling is associated with breast cancer growth. Estrogen can exert physiological actions via estrogen receptors α/β (ERα/β). There is experimental evidence suggesting that in ERα/β-positive breast cancer, ERα promotes tumor cell proliferation and ERβ inhibits ERα-mediated transcriptional activity, resulting in abrogation of cell growth. Therefore, ERβ is attracting attention as a potential tumor suppressor, and as a biomarker and therapeutic target in the ERα/β-positive breast cancer. Based on this information, we have hypothesized that some endocrine-disrupting chemicals (EDCs) that can perturb the balance between ERα and ERβ expression levels in breast cancer cells might have effects on the breast cancer proliferation (i.e., down-regulation of the α-type of ER). We have recently reported that 4-methyl-2,4-bis(4-hydroxyphenyl)pent-1-ene (MBP), an active metabolite of bisphenol A, in ERα/β-positive human breast cancer significantly down-regulates ERα expression, yet stimulates cell proliferation through the activation of ERβ-mediated transcription. These results support our hypothesis by demonstrating that exposure to MBP altered the functional role of ERβ in breast cancer cells from suppressor to promoter. In contrast, some EDCs, such as Δ⁹-tetrahydrocannabinol and bisphenol AF, can exhibit anti-estrogenic effects through up-regulation of ERβ expression without affecting the ERα expression levels. However, there is no consensus on the correlation between ERβ expression levels and clinical prognosis, which might be due to differences in exposed chemicals. Therefore, elucidating the exposure effects of EDCs can reveal the reason for inconsistent functional role of ERβ in ERα/β-positive breast cancer.

Role of Polyphenols in the Metabolism of the Skeletal System in Humans and Animals – A Review

Polyphenols are a group of compounds arousing enormous interest due to their multiple effects on both human and animal health and omnipresence in plants. A number of in vitro and animal model studies have shown that all polyphenols exhibit anti-inflammatory and antioxidant activities, and play a significant role against oxidative stress-related pathologies. They also exert gut promotory effects and prevent chronic degenerative diseases. However, less attention has been paid to the potential influence of polyphenols on bone properties and metabolism. It is well known that proper growth and functioning of the organism depend largely on bone growth and health. Therefore, understanding the action of substances (including polyphenols) that may improve the health and functioning of the skeletal system and bone metabolism is extremely important for the health of the present and future generations of both humans and farm animals. This review provides a comprehensive summary of literature related to causes of bone loss during ageing of the organism (in both humans and animals) and possible effects of dietary polyphenols preventing bone loss and diseases. In particular, the underlying cellular and molecular mechanisms that can modulate skeletal homeostasis and influence the bone modeling and remodeling processes are presented.

A Short S-Equol Exposure Has a Long-Term Inhibitory Effect on Adipogenesis in Mouse 3T3-L1 Cells

In the search for new drugs against obesity, the chronic disease that threatens human health worldwide, several works have focused on the study of estrogen homologs because of the role of estrogen receptors (ERs) in adipocyte growth. The isoflavone equol, an ERβ agonist, has shown beneficial metabolic effects in in vivo and in vitro assays; however, additional studies are required to better characterize its potential for body weight control. Here, we showed that the treatment of 3T3-L1 cells with 10 μM of S-equol for the first three days of the adipocyte differentiation protocol was able to prevent cells becoming semi-rounded and having a lipid droplet formation until the seventh day of culture; moreover, lipid accumulation was reduced by about 50%. Congruently, S-equol induced a reduction in mRNA expression of the adipogenic markers C/EBPα and PPARγ, and adipokines secretion, mainly Adiponectin, Leptin, Resistin, and MCP-1, while the release of PAI-1 was augmented. Moreover, it also reduced the expression of ERα and attenuated the subexpression of ERβ associated with adipogenesis. Altogether, our data suggested that S-equol binding to ERβ affects the transcriptional program that regulates adipogenesis and alters adipocyte functions. Future efforts will focus on studying the impact of S-equol on ER signaling pathways.

Sex Differences, Estrogen Metabolism and Signaling in the Development of Pulmonary Arterial Hypertension

Pulmonary arterial hypertension (PAH) is a complex and devastating disease with a poor long-term prognosis. While women are at increased risk for developing PAH, they exhibit superior right heart function and higher survival rates than men. Susceptibility to disease risk in PAH has been attributed, in part, to estrogen signaling. In contrast to potential pathological influences of estrogen in patients, studies of animal models reveal estrogen demonstrates protective effects in PAH. Consistent with this latter observation, an ovariectomy in female rats appears to aggravate the condition. This discrepancy between observations from patients and animal models is often called the "estrogen paradox." Further, the tissue-specific interactions between estrogen, its metabolites and receptors in PAH and right heart function remain complex; nonetheless, these relationships are essential to characterize to better understand PAH pathophysiology and to potentially develop novel therapeutic and curative targets. In this review, we explore estrogen-mediated mechanisms that may further explain this paradox by summarizing published literature related to: (1) the synthesis and catabolism of estrogen; (2) activity and functions of the various estrogen receptors; (3) the multiple modalities of estrogen signaling in cells; and (4) the role of estrogen and its diverse metabolites on the susceptibility to, and progression of, PAH as well as their impact on right heart function.