Nuclear Estrogen Receptor Research Articles

Association of growth differentiation factor 9 expression with nuclear receptor and basic helix-loop-helix transcription factors in buffalo oocytes during in vitro maturation

Abstract Growth differentiation factor 9 (GDF9) is an oocyte-specific paracrine factor involved in bidirectional communication, which plays an important role in oocyte developmental competence. In spite of its vital role in reproduction, there is insufficient information about exact transcriptional control mechanism of GDF9. Hence, present study was undertaken with the aim to study the expression of basic helix-loop-helix (bHLH) transcription factors (TFs) such as the factor in the germline alpha (FIGLA), twist-related protein 1 (TWIST1) and upstream stimulating factor 1 and 2 (USF1 and USF2), and nuclear receptor (NR) superfamily TFs like germ cell nuclear factor (GCNF) and oestrogen receptor 2 (ESR2) under three different in vitro maturation (IVM) groups [follicle-stimulating hormone (FSH), insulin-like growth factor-1 (IGF1) and oestradiol)] along with all supplementation group as positive control, to understand their role in regulation of GDF9 expression. Buffalo cumulus–oocyte complexes were aspirated from abattoir-derived ovaries and matured in different IVM groups. Following maturation, TFs expression was studied at 8 h of maturation in all four different IVM groups and correlated with GDF9 expression. USF1 displayed positive whereas GCNF, TWIST1 and ESR2 revealed negative correlation with GDF9 expression. TWIST1 & ESR2 revealing negative correlation with GDF9 expression were found to be positively correlated amongst themselves also. GCNF & USF1 revealing highly significant correlation with GDF9 expression in an opposite manner were found to be negatively correlated. The present study concludes that the expression of GDF9 in buffalo oocytes remains under control through the involvement of NR and bHLH TFs.

Sociodemographic and dietary predictors of maternal and placental mycoestrogen concentrations in a US pregnancy cohort.

Zearalenone (ZEN) is a mycotoxin contaminating grains and processed foods. ZEN alters nuclear estrogen receptor α/β signaling earning its designation as a mycoestrogen. Experimental evidence demonstrates that mycoestrogen exposure during pregnancy is associated with altered maternal sex steroid hormones, changes in placental size, and decreases in fetal weight and length. While mycoestrogens have been detected in human biospecimens worldwide, exposure assessment of ZEN in US populations, particularly during pregnancy, is lacking. To characterize urinary and placental concentrations of ZEN and its metabolites in healthy US pregnant people and examine demographic, perinatal, and dietary predictors of exposure. Urine samples were collected in each trimester from pregnant participants in the UPSIDE study and placenta samples were collected at delivery (Rochester, NY, n = 317). We used high performance liquid chromatography and high-resolution tandem mass spectrometry to measure total urinary (ng/ml) and placental mycoestrogens (ng/g). Using linear regression and linear mixed effect models, we examined associations between mycoestrogen concentrations and demographic, perinatal, and dietary factors (Healthy Eating Index [HEI], ultra-processed food [UPF] consumption). Mycoestrogens were detected in 97% of urines (median 0.323 ng/ml) and 84% of placentas (median 0.012 ng/g). Stability of urinary mycoestrogens across pregnancy was low (ICC: 0.16-0.22) and did not correlate with placental levels. In adjusted models, parity (multiparous) and pre-pregnancy BMI (higher) predicted higher urinary concentrations. Birth season (fall) corresponded with higher placental mycoestrogens. Dietary analyses indicated that higher HEI (healthier diets) predicted lower exposure (e.g., Σmycoestrogens %∆ -2.03; 95%CI -3.23, -0.81) and higher percent calories from UPF predicted higher exposure (e.g., Σmycoestrogens %∆ 1.26; 95%CI 0.29, 2.24). The mycotoxin, zearalenone (ZEN), has been linked to adverse health and reproductive impacts in animal models and livestock. Despite evidence of widespread human exposure, relatively little is known about predictors of exposure. In a pregnant population, we observed that maternal ZEN concentrations varied by maternal pre-pregnancy BMI and parity. Consumption of ultra-processed foods, added sugars, and refined grains were linked to higher ZEN concentrations while healthier diets were associated with lower levels. Our research suggests disparities in exposure that are likely due to diet. Further research is needed to understand the impacts of ZEN on maternal and offspring health.

Insights on estetrol, the native estrogen: from contraception to hormone replacement therapy.

Estetrol (E4) is a natural estrogen that has recently emerged as new option for contraception and hormone replacement therapy (HRT). Unlike other estrogens, E4 primarily stimulates nuclear estrogen receptor alpha (ERα) and does not activate membrane ERα. For this reason, this novel estrogen has tissue-specific effects across various organs such as liver, vascular endothelium, mammary glands, brain, vagina, and uterus. The selective activation of the nuclear ERα results in distinct pharmacological properties that contribute to its unique therapeutic profile. Moreover, E4 shows minimal interaction with the hepatic cytochrome P450 enzyme system, leading to a favorable pharmacokinetic profile and a reduced potential for drug-drug interactions. Currently, E4 is commercially available in combination with drospirenone as a combined oral contraceptive and its application in HRT is undergoing late-stage clinical development. Many studies have demonstrated that E4 has a lower impact on hemostatic and metabolic parameters compared to other estrogens, potentially reducing the risk of adverse effects commonly associated with hormonal therapies such as thromboembolic events or dyslipidemia. Beyond its role in contraception and HRT, E4 shows promising therapeutic potential in other medical fields, including neuroprotection in neonatal hypoxic-ischemic encephalopathy, enhancement of hematopoietic stem cell transplantation outcomes and prostate cancer management. This review synthesizes the latest evidence on E4 primarily focusing on its pharmacological characteristics and clinical applications. The findings suggest that E4 versatility and peculiar mechanism of action may represent an important therapeutic option for a broad spectrum of medical conditions.

P25-12 Effects of personalized chemical mixture on endocrine disruption based on estrogen nuclear receptors

P25-12 Effects of personalized chemical mixture on endocrine disruption based on estrogen nuclear receptors

Abstract P447: Impact of Altered Receptor Expression On the Cardiovascular Response to Estrogen

Premenopausal women benefit from estrogen's protective effects, including lower arterial stiffness than men of the same age. Despite estrogen's protective role, menopausal hormone therapy showed no cardiovascular benefits in the Women's Health Initiative. One theory is that the response to menopausal hormone therapy is modulated by the presence of pre-existing cardiovascular disease. Estrogen signals through nuclear estrogen receptors ERα and ERβ, and the membrane-bound G protein-coupled estrogen receptor (GPER). Our lab has shown that GPER induces protective cardiovascular effects including decreased blood pressure, protection from renal damage, and attenuation of arterial remodeling. In this study, we hypothesized that GPER deletion would attenuate the protective vascular effects of estrogen after menopause. Female C57Bl/6J wildtype (wt) and global GPER knockout (ko) mice underwent ovariectomy (OVX) at 46 weeks of age and concurrently administered estrogen (E) or vehicle (Veh). Angiotensin II (Ang II; 700 ng/kg/day) infusion was used to induce hypertension either four weeks prior (Ang-E) or at the time of OVX (E-Ang) to evaluate the impact of cardiovascular diseases preceding or coinciding with menopause. Blood pressure was measured by tail-cuff plethysmography and arterial stiffness was assessed by pulse wave velocity (PWV). Statistical analysis was performed using one-way ANOVA. Ang II induced a similar level of hypertension in wt and ko mice and was not impacted by E or timing. In wt mice, PWV was significantly higher in Veh-treated compared with E-treated hypertensive animals, independent of timing (P<0.001). In contrast, PWV was not impacted by E in GPER ko mice (P=0.99). In conclusion, we found that E did not affect the hypertensive response to Ang II in both wt and GPER ko mice. GPER deletion reduced estrogen’s protection from arterial stiffening. Whether Ang II preceded or coincided with menopause did not alter the effects of E. These studies are important for determining whether cardiovascular status should be a factor when considering menopausal hormone therapy.

Selective Estrogen Receptor Modulators' (SERMs) Influence on TET3 Expression in Breast Cancer Cell Lines with Distinct Biological Subtypes.

Tamoxifen, a selective estrogen receptor modulator (SERM), exhibits dual agonist or antagonist effects contingent upon its binding to either G-protein-coupled estrogen receptor (GPER) or estrogen nuclear receptor (ESR). Estrogen signaling plays a pivotal role in initiating epigenetic alterations and regulating estrogen-responsive genes in breast cancer. Employing three distinct breast cancer cell lines-MCF-7 (ESR+; GPER+), MDA-MB-231 (ESR-; GPER-), and SkBr3 (ESR-; GPER+)-this study subjected them to treatment with two tamoxifen derivatives: 4-hydroxytamoxifen (4-HT) and endoxifen (Endox). Through 2D high-performance liquid chromatography with tandem mass spectrometry detection (HPLC-MS/MS), varying levels of 5-methylcytosine (5-mC) were found, with MCF-7 displaying the highest levels. Furthermore, TET3 mRNA expression levels varied among the cell lines, with MCF-7 exhibiting the lowest expression. Notably, treatment with 4-HT induced significant changes in TET3 expression across all cell lines, with the most pronounced increase seen in MCF-7 and the least in MDA-MB-231. These findings underscore the influence of tamoxifen derivatives on DNA methylation patterns, particularly through modulating TET3 expression, which appears to be contingent on the presence of estrogen receptors. This study highlights the potential of targeting epigenetic modifications for personalized anti-cancer therapy, offering a novel avenue to improve treatment outcomes.

Reproductive function and behaviors: an update on the role of neural estrogen receptors alpha and beta.

Infertility is becoming a major public health problem, with increasing frequency due to medical, environmental and societal causes. The increasingly late age of childbearing, growing exposure to endocrine disruptors and other reprotoxic products, and increasing number of medical reproductive dysfunctions (endometriosis, polycystic ovary syndrome, etc.) are among the most common causes. Fertility relies on fine-tuned control of both neuroendocrine function and reproductive behaviors, those are critically regulated by sex steroid hormones. Testosterone and estradiol exert organizational and activational effects throughout life to establish and activate the neural circuits underlying reproductive function. This regulation is mediated through estrogen receptors (ERs) and androgen receptor (AR). Estradiol acts mainly via nuclear estrogen receptors ERα and ERβ. The aim of this review is to summarize the genetic studies that have been undertaken to comprehend the specific contribution of ERα and ERβ in the neural circuits underlying the regulation of the hypothalamic-pituitary-gonadal axis and the expression of reproductive behaviors, including sexual and parental behavior. Particular emphasis will be placed on the neural role of these receptors and the underlying sex differences.

The Dicentrarchus labrax estrogen screen test: A relevant tool to screen estrogen-like endocrine disrupting chemicals in the aquatic environment

In response to the need for the diversification of regulatory bioassays to screen estrogen-like endocrine disrupting chemical (EEDC) in the environment, we propose the use of a reporter gene assay involving all nuclear estrogen receptors from Dicentrarchus labrax (i.e., sbEsr1, sbEsr2a, or sbEsr2b). Named DLES test (D. labrax estrogen screen), it aims at complementing existing standardized in vitro tests by implementing more estrogen receptors notably those that do not originate from humans.Positive responses were obtained with all three estrogen receptors, and—consistently with observations from other species—variations in sensitivity to E2 were measured. Sensitivity and EC50 values could be classified as follows: sbEsr2b < sbEsr2a < sbEsr1. The pharmacological characterization with a human estrogen receptor antagonist (fulvestrant) successfully validated the specific involvement of each sbEsr and evidenced the capacity of the DLES test to highlight antagonist interactions. The DLES test was applied to WWTP contaminant extracts. A positive response was detected in the inflow sample in accordance with the YES test, but not in the outflow sample. Notwithstanding, the DLES test (sbEsr2b) exhibited greater sensitivity for the screening of those samples. This study demonstrates the need for more comprehensive testing including representatives of marine species for a better detection of EEDCs. The DLES test appears as a pertinent tool to predict adverse effects and to widen the scope of screening and hazard assessment of EEDCs in the environment.

Roles of estrogen receptors during sexual reversal in Pelodiscus sinensis.

The Chinese soft-shelled turtle, Pelodiscus sinensis, exhibits distinct sexual dimorphism, with the males growing faster and larger than the females. During breeding, all-male offspring can be obtained using 17β-estradiol (E2). However, the molecular mechanisms underlying E2-induced sexual reversal have not yet been elucidated. Previous studies have investigated the molecular sequence and expression characteristics of estrogen receptors (ERs). In this study, primary liver cells and embryos of P. sinensis were treated with ER agonists or inhibitors. Cell incubation experiments revealed that nuclear ERs (nERs) were the main pathway for the transmission of estrogen signals. Our results showed that ERα agonist (ERα-ag) upregulated the expression of Rspo1, whereas ERα inhibitor (ERα-Inh) downregulated its expression. The expression of Dmrt1 was enhanced after ERα-Inh + G-ag treatment, indicating that the regulation of male genes may not act through a single estrogen receptor, but a combination of ERs. In embryos, only the ERα-ag remarkably promoted the expression levels of Rspo1, Wnt4, and β-catenin, whereas the ERα-Inh had a suppressive effect. Additionally, Dmrt1, Amh, and Sox9 expression levels were downregulated after ERβ inhibitor (ERβ-Inh) treatment. GPER agonist (G-ag) has a significant promotion effect on Rspo1, Wnt4, and β-catenin, while the inhibitor G-Inh does not affect male-related genes. Overall, these results suggest that ERs play different roles during sexual reversal in P. sinensis and ERα may be the main carrier of estrogen-induced sexual reversal in P. sinensis. Further studies need to be performed to analyze the mechanism of ER action.

Estrogen promotes gonadotropin-releasing hormone expression by regulating tachykinin 3 and prodynorphin systems in chicken

The "KNDy neurons" located in the hypothalamic arcuate nucleus (ARC) of mammals are known to co-express kisspeptin, neurokinin B (NKB), and dynorphin (DYN), and have been identified as key mediators of the feedback regulation of steroid hormones on gonadotropin-releasing hormone (GnRH). However, in birds, the genes encoding kisspeptin and its receptor GPR54 are genomic lost, leaving unclear mechanisms for feedback regulation of GnRH by steroid hormones. Here, the genes tachykinin 3 (TAC3) and prodynorphin (PDYN) encoding chicken NKB and DYN neuropeptides were successfully cloned. Temporal expression profiling indicated that TAC3, PDYN and their receptor genes (TACR3, OPRK1) were mainly expressed in the hypothalamus, with significantly higher expression at 30W than at 15W. Furthermore, overexpression or interference of TAC3 and PDYN can regulate the GnRH mRNA expression. In addition, in vivo and in vitro assays showed that estrogen (E2) could promote the mRNA expression of TAC3, PDYN, and GnRH, as well as the secretion of GnRH/LH. Mechanistically, E2 could dimerize the nuclear estrogen receptor 1 (ESR1) to regulate the expression of TAC3 and PDYN, which promoted the mRNA and protein expression of GnRH gene as well as the secretion of GnRH. In conclusion, these results revealed that E2 could regulate the GnRH expression through TAC3 and PDYN systems, providing novel insights for reproductive regulation in chickens.

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.

Abstract 6877: Progesterone promotes immunosuppression in the murine mammary gland by causing T cell death

Abstract Breast Cancer is the most common cancer diagnosed in women in the United States. Second only to lung cancer, breast cancer results in the greatest number of cancer deaths for women. Hormone receptor positive (HR+) breast cancers - cancers expressing the nuclear receptors for steroid hormones estrogen and progesterone, termed the estrogen receptor (ER) and progesterone receptor (PR) - make up the largest proportion of diagnosed breast cancers by a significant margin. So, although the HR+ subtype is less aggressive compared to others, it continues to be the largest contributor to breast cancer mortality. Treatment consists of anti-endocrine therapies, largely targeting ER/estrogen, the established drivers of breast cancer growth. Most women respond well to these therapies, but for women who do not, there are few alternative options. With the advent of immunotherapy and its successes in treating and controlling certain tumor types, many were hopeful that it could be employed for breast cancer as well. However, breast cancers, especially HR+ breast cancers, are considered “immune cold.” They lack high proportions of tumor-infiltrating lymphocytes (TILs), have low neoantigen production, and high percentages of immunosuppressive cells. A contributing factor could be the hormones present in the tumor microenvironment. The accepted paradigm is that lifetime exposure to estrogens drives the development of HR+ breast cancer, but both estrogen and progesterone are part of the normal menstrual cycle. Prior work from our lab has uncovered a novel immune-modulatory role for progesterone, pivotal to promoting the growth of PR-positive mammary tumors. Recent preliminary data from our lab show that progesterone treatment conveys immune protection against T cell killing in a co-culture with E0771 mammary gland tumor cells. However, when activated in monoculture, T cells exposed to increasing concentrations of progesterone have no differing expression of cell surface activation or exhaustion markers, implying that progesterone is not eliciting this effect by interfering with the T cell activation cascade nor is it inducing premature exhaustion. Interestingly, progesterone treatment instead leads to a concentration-dependent increase in T cell death compared to the untreated control. In vivo, these results are supported as progesterone treatment decreases the amount of total CD3+ T cells, and specifically the cytotoxic CD8+ subset, in the mammary glands of mice. These results suggest that progesterone could modulate the breast and tumor microenvironment, providing tumor cells with protection from immunosurveillance and contributing to HR+ breast cancer development. These data also argue for the use of anti-progestins to be added to the HR+ breast cancer treatment regimen to boost anti-tumor immune activity. Citation Format: Amanda Heard, Lauryn R. Werner, Eilidh I. Chowanec, Harmony Saunders, Julio Tinoco, Zachary C. Hartman, Christy R. Hagan. Progesterone promotes immunosuppression in the murine mammary gland by causing T cell death [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6877.

Low thrombin generation in postmenopausal women using estetrol

Objective Estetrol (E4) represents a novel estrogen of interest to relieve vasomotor symptoms. E4 activates the nuclear estrogen receptor α (ERα) but antagonizes the estradiol ERα-dependent membrane-initiated steroid signaling pathway. The distinct pharmacological properties of E4 could explain its low impact on hemostasis. This study aimed to assess the effect of E4 on coagulation in postmenopausal women, using the thrombin generation assay (TGA). Methods Data were collected from a multicenter, randomized, placebo-controlled, dose-finding study in postmenopausal women (NCT02834312). Oral E4 (2.5 mg, n = 42; 5 mg, n = 29; 10 mg, n = 34; or 15 mg, n = 32) or placebo (n = 31) was administered daily for 12 weeks. Thrombograms and TGA parameters were extracted for each subject at baseline and after 12 weeks of treatment. Results After 12 weeks of treatment, all treatment groups showed a mean thrombogram (±95% confidence interval [CI] of the mean) within the reference ranges, that is, the 2.5th–97.5th percentile of all baseline thrombograms (n = 168), as well as for TGA parameters. Conclusions The intake of E4 15 mg for 12 weeks led to significant but not clinically relevant changes compared to baseline as the mean values (±95% CI of the mean) remained within reference ranges, demonstrating a neutral profile of this estrogen on hemostasis.

G Protein-Coupled Estrogen Receptor (GPER) and ERs Are Modulated in the Testis-Epididymal Complex in the Normal and Cryptorchid Dog.

There is growing evidence by the literature that the unbalance between androgens and estrogens is a relevant condition associated with a common canine reproductive disorder known as cryptorchidism. The role of estrogens in regulating testicular cell function and reproductive events is supposedly due to the wide expression of two nuclear estrogen receptors (ERs), ER-alpha and ER-beta and a trans-membrane G protein-coupled estrogen receptor (GPER) in the testis. In this study, immunohistochemistry, Western blotting and qRT-PCR were used to assess the distribution and expression of GPER in the testis-epididymal complex in the normal and cryptorchid dog. ER-alpha and ER-beta were also evaluated to better characterize the relative abundances of all three receptors. In addition, in these tissues, the expression level of two proteins as SOD1 and Nrf2 normally associated with oxidative stress was investigated to evaluate a possible relationship with ERs. Our data revealed changes in the distribution and expression of the GPER between the normal and cryptorchid dog. In particular, dogs affected by cryptorchidism showed an upregulation of GPER at level of the examined reproductive tract. Also considering the obtained result of a modulation of SOD1 and Nrf2 expression, we could hypothesize the involvement of GPER in the cryptorchid condition. Further studies are, however, necessary to characterize the role of GPER and its specific signaling mechanisms.

Physicochemical characterization of B-hydroxyphenyl phosphine borane derivatives and their evaluation as nuclear estrogen receptor ligands.

Increasing the structural options in medicinal chemistry is a promising approach to develop new drug candidates. In this research, we designed and synthesized a series of B-hydroxyphenyl phosphine borane derivatives and investigated their structure-property and structure-activity relationships. The synthesized B-phenylphosphine borane derivatives exhibited sufficient stability in aqueous media, weaker hydrophobicity than the corresponding alkanes and silanes, and sufficient affinity for lipid membranes to enable permeability. Several B-hydroxyphenyl phosphine borane derivatives exhibited significant estrogen receptor (ER) agonistic activity with superior ligand-lipophilicity efficiency (LLE). The phosphine borane framework appears to be a promising option for structural development in drug discovery studies.

Sex and interspecies differences in ESR2-expressing cell distributions in mouse and rat brains

BackgroundESR2, a nuclear estrogen receptor also known as estrogen receptor β, is expressed in the brain and contributes to the actions of estrogen in various physiological phenomena. However, its expression profiles in the brain have long been debated because of difficulties in detecting ESR2-expressing cells. In the present study, we aimed to determine the distribution of ESR2 in rodent brains, as well as its sex and interspecies differences, using immunohistochemical detection with a well-validated anti-ESR2 antibody (PPZ0506).MethodsTo determine the expression profiles of ESR2 protein in rodent brains, whole brain sections from mice and rats of both sexes were subjected to immunostaining for ESR2. In addition, to evaluate the effects of circulating estrogen on ESR2 expression profiles, ovariectomized female mice and rats were treated with low or high doses of estrogen, and the resulting numbers of ESR2-immunopositive cells were analyzed. Welch’s t-test was used for comparisons between two groups for sex differences, and one-way analysis of variance followed by the Tukey–Kramer test were used for comparisons among multiple groups with different estrogen treatments.ResultsESR2-immunopositive cells were observed in several subregions of mouse and rat brains, including the preoptic area, extended amygdala, hypothalamus, mesencephalon, and cerebral cortex. Their distribution profiles exhibited sex and interspecies differences. In addition, low-dose estrogen treatment in ovariectomized female mice and rats tended to increase the numbers of ESR2-immunopositive cells, whereas high-dose estrogen treatment tended to decrease these numbers.ConclusionsImmunohistochemistry using the well-validated PPZ0506 antibody revealed a more localized expression of ESR2 protein in rodent brains than has previously been reported. Furthermore, there were marked sex and interspecies differences in its distribution. Our histological analyses also revealed estrogen-dependent changes in ESR2 expression levels in female brains. These findings will be helpful for understanding the ESR2-mediated actions of estrogen in the brain.

Sex Differences in Colon Cancer: Genomic and Nongenomic Signalling of Oestrogen.

Colon cancer (CRC) is a prevalent malignancy that exhibits distinct differences in incidence, prognosis, and treatment responses between males and females. These disparities have long been attributed to hormonal differences, particularly the influence of oestrogen signalling. This review aims to provide a comprehensive analysis of recent advances in our understanding of the molecular mechanisms underlying sex differences in colon cancer and the protective role of membrane and nuclear oestrogen signalling in CRC development, progression, and therapeutic interventions. We discuss the epidemiological and molecular evidence supporting sex differences in colon cancer, followed by an exploration of the impact of oestrogen in CRC through various genomic and nongenomic signalling pathways involving membrane and nuclear oestrogen receptors. Furthermore, we examine the interplay between oestrogen receptors and other signalling pathways, in particular the Wnt/β-catenin proliferative pathway and hypoxia in shaping biological sex differences and oestrogen protective actions in colon cancer. Lastly, we highlight the potential therapeutic implications of targeting oestrogen signalling in the management of colon cancer and propose future research directions to address the current gaps in our understanding of this complex phenomenon.

Role for Nongenomic Estrogen Signaling in Male Fertility.

Estrogen actions are mediated by both nuclear (n) and membrane (m) localized estrogen receptor 1 (ESR1). Male Esr1 knockout (Esr1KO) mice lacking functional Esr1 are infertile, with reproductive tract abnormalities. Male mice expressing nESR1 but lacking mESR1 (nuclear-only estrogen receptor 1 mice) are progressively infertile due to testicular, rete testis, and efferent ductule abnormalities similar to Esr1KO males, indicating a role for mESR1 in male reproduction. The H2NES mouse expresses only mESR1 but lacks nESR1. The goal of this study was to identify the functions of mESR1 alone in mice where nESR1 was absent. Breeding trials showed that H2NES males are fertile, with decreased litter numbers but normal pup numbers/litter. In contrast to Esr1KO mice, H2NES testicular, and epididymal weights were not reduced, and seminiferous tubule abnormalities were less pronounced. However, Esr1KO and H2NES males both had decreased sperm motility and a high incidence of abnormal sperm morphology. Seminiferous tubule and rete testis dilation and decreased efferent ductule epithelial height characteristic of Esr1KO males were reduced in H2NES. Consistent with this, expression of genes involved in fluid transport and ion movement that were reduced in Esr1KO (Aqp1, Car2, Car14, Cftr) were partially or fully restored to wild-type levels in H2NES. In summary, in contrast to Esr1KO males, H2NES males are fertile and have reduced phenotypic and functional abnormalities in the testis and efferent ductules. Thus, mESR1 alone, in the absence of nESR1, can partially regulate male reproductive tract structure and function, emphasizing its importance for overall estrogen action.

17β-Estradiol mediates TGFBR3/Smad2/3 signaling to attenuate the fibrosis of TGF-β1-induced bovine endometrial epithelial cells via GPER.

Abnormal function and fibrosis of endometrium caused by cows' endometritis pose difficult implantation of embryos and uterine cavity adhesions. 17β-Estradiol (E2) serves as the most effective aromatized estrogen, and its synthetase and receptors have been detected in the endometrium. Studies have demonstrated the positive role of estrogen in combating pathological fibrosis in diverse diseases. However, it is still unknown whether E2 regulates endometrium fibrosis in bovine endometritis. Herein, we evaluated the expression patterns of transforming growth factor-β1 (TGF-β1), epithelial-mesenchymal transformation (EMT)-related proteins (α-SMA, vimentin N-cadherin and E-cadherin), cytochrome P450 19A1 (CYP19A1), and G protein-coupled estrogen receptor (GPER) in bovine healthy endometrium and Inflammatory endometrium. Our data showed that the inflamed endometrium presented low CYP19A1 and GPER expression, and significantly higher EMT process versus the normal tissue. Moreover, we established a TGF-β1-induced fibrosis model in BEND cells, and found that E2 inhibited the EMT process of BEND cells in a dose-dependent manner. The anti-fibrotic effect of E2 was blocked by the GPER inhibitor G15, but not the estrogen nuclear receptors (ERs) inhibitor ICI182780. Moreover, the GPER agonist G1 inhibited fibrosis and Smad2/3 phosphorylation but increased the expression of TGFBR3 in BEND cells. Transfection with TGFBR3 small interfering RNA blocked the effect of G1 on fibrosis of BEND cells and upregulated the expression of P-Smad2/3. Our in vivo data also showed that E2 and G1 affected uterus fibrosis in mice endometritis model caused by LPS, which was associated with the inhibition of TGFBR3/Smad2/3 signaling. In conclusion, our data implied that E2 alleviates the fibrosis of TGF-β1-induced BEND cells, which is associated with the GPER mediation of TGFBR3/Smad2/3 signaling.

Evolutionary history and functional characterization of duplicated G protein-coupled estrogen receptors in European sea bass

Across vertebrates, the numerous estrogenic functions are mainly mediated by nuclear and membrane receptors, including the G protein-coupled estrogen receptor (GPER) that has been mostly associated with rapid non-genomic responses. Although Gper-mediated signalling has been characterized in only few fish species, Gpers in fish appear to present more mechanistic functionalities as those of mammals due to additional gene duplicates. In this study, we ran a thorough investigation of the fish Gper evolutionary history in light of available genomes, we carried out the functional characterization of the two gper gene duplicates of European sea bass (Dicentrarchus labrax) using luciferase reporter gene transactivation assays, validated it with natural and synthetic estrogen agonists/antagonists and applied it to other chemicals of aquaculture and ecotoxicological interest. Phylogenetic and synteny analyses of fish gper1 and gper1-like genes suggest their duplication may have not resulted from the teleost-specific whole genome duplication. We confirmed that both sbsGper isoforms activate the cAMP signalling pathway and respond differentially to distinct estrogenic compounds. Therefore, as observed for nuclear estrogen receptors, both sbsGpers duplicates retain estrogenic activity although they differ in their specificity and potency (Gper1 being more potent and more specific than Gper1-like), suggesting a more conserved role for Gper1 than for Gper1-like. In addition, Gpers were able to respond to estrogenic environmental pollutants known to interfere with estrogen signalling, such as the phytoestrogen genistein and the anti-depressant fluoxetine, a point that can be taken into account in aquatic environment pollution screenings and chemical risk assessment, complementing previous assays for sea bass nuclear estrogen receptors.