Regulation Of Estrogen Receptor Research Articles

Upregulation of GREB1 in colorectal cancer ovarian metastases may be a potential therapeutic target.

e15596 Background: Classification of ovarian metastases (OM) in colorectal cancer (CRC) as peritoneal metastasis (PM) remains controversial. Moreover, OM demonstrate resistance to systemic therapy, suggesting distinct molecular tumorigenesis. Gene expression profiling and transcriptomic analysis was performed to distinguish OM, PM, and primary CRC (pCRC) and identify potential therapeutic targets. Methods: RNA sequencing was performed on tissue from the Total Cancer Care database. Raw counts were scaled in reads per million to filter out low-expressed genes. Afterward, raw counts of retained genes were normalized in trimmed mean of M-values and then log2-transformed using the Limma R package. Genes with a |Log2FC| > 0.58 and an adjusted p-value < 0.05 were considered dysregulated. In silico motif enrichment analysis of estrogen receptor 1 (ESR1) on growth regulating estrogen receptor binding 1 (GREB1) was conducted via the FIMO program. Results: There were 115 patients with tissue from OM (n = 6), PM (n = 4), and pCRC (n = 105). The average age was 58 years and most patients were male (57.4%), Caucasian (89.5%), and had microsatellite stable disease (69.6%). Most patients underwent cytotoxic chemotherapy (67%), while fewer underwent targeted therapy (38.3%) or radiation therapy (27.8%). The median overall survival for the pCRC, OM, and PM populations was 7.1, 3.4, and 4.0 months, respectively. Among upregulated genes, LAMC3, SCUBE1, and GREB1 had the highest differential expression in OM compared to PM and PEG3, C7, and GREB1 had the highest differential expression in OM compared to pCRC (all p < 0.001). Among downregulated genes, IGLC1, IGHG2, and IGHG1 had the greatest differential expression in OM compared to PM and IGHG1, IGKV4-1, and MMP12 had the greatest differential expression in OM compared to pCRC (all p < 0.001, Figure 1). GREB1 was upregulated in OM compared to both PM and pCRC. There are two estrogen response element (ERE) sites within the promoter region of GREB1. ESR1 transcription factor was shown to bind to these ERE (p < 0.001). Conclusions: Transcriptomic analysis demonstrated clear molecular distinction between OM, PM and pCRC. Differences in gene expression profiling suggest distinct underlying mechanisms of metastasis. We identified a significant upregulation of GREB1 in OM compared to PM and pCRC. GREB1 contains both ERE and ESR1 in the upstream promoter regions implying potential upstream transcription regulation mediated by ESR1. GREB1 is a potential novel, hormonal target in treatment of OM in CRC. Continued analysis is ongoing to identify other potential targets.

Bioinformatics and In Vitro Study Reveal ERα as The Potential Target Gene of Honokiol to Enhance Trastuzumab Sensitivity in HER2+ Trastuzumab-Resistant Breast Cancer Cells

Trastuzumab resistance presents a significant challenge in the treatment of HER2+ breast cancer, necessitating the investigation of combination therapies to overcome this resistance. Honokiol, a compound with broad anticancer activity, has shown promise in this regard. This study aims to discover the effect of honokiol in increasing trastuzumab sensitivity in HER2+ trastuzumab-resistant breast cancer cells HCC1954 and the underline mechanisms behind. A bioinformatics study performed to explore the most potential target hub gene for honokiol in HER2+ breast cancer. Honokiol, trastuzumab and combined treatment cytotoxicity activity was then evaluated in both parental HCC1954 and trastuzumab resistance (TR-HCC1954) cells using MTT assay. The expression levels of these hub genes were then analyzed using qRT-PCR and those that could not be analyzed were subjected to molecular docking to determine their potential. Honokiol showed a potent cytotoxicity activity with an IC50 of 41.05 μM and 69.61 μM in parental HCC1954 and TR-HCC1954 cell line respectively. Furthermore, the combination of honokiol and trastuzumab resulted in significant differences in cytotoxicity in TR-HCC1954 cells at specific concentrations. Molecular docking and the qRT-PCR showed that the potential ERα identified from the bioinformatics analysis was affected by the treatment. Our results show that honokiol has the potential to increase the sensitivity of trastuzumab in HER2+ trastuzumab resistant breast cancer cell line HCC1954 by affecting regulating estrogen receptor signaling. Further research is necessary to validate these findings.

Estrogen receptor regulation of the Immune Microenvironment in Breast Cancer

Breast cancer (BCa) is the most common cancer in women and the estrogen receptor (ER)+ subtype is increasing in incidence. There are numerous therapy options available for patients that target the ER, however issues such as innate and acquired treatment resistance, and treatment related side effects justify research into alternative therapeutic options for these patients. Patients of many solid tumour types have benefitted from immunotherapy, however response rates have been generally low in ER+ BCa. We summarise the recent work assessing CDK4/6 inhibitors for ER+ BCa and how they have been shown to prime anti-tumour immune cells and achieve impressive results in preclinical models. A great example of how the immune system might be activated against ER+ BCa. We review the role of estrogen signalling in immune cells, and explore recent data highlighting the hormonal regulation of the immune microenvironment of normal breast, BCa and immune disorders. As recent data has indicated that macrophages are particularly susceptible to estrogen signalling, we highlight macrophage phagocytosis as a key potential target for priming the tumour immune microenvironment. We challenge the generally accepted paradigm that ER+ BCa are "immune-cold" - advocating instead for research into therapies that could be used in combination with targeted therapies and/or immune checkpoint blockade to achieve durable antitumour responses in ER+ BCa.

TRPS1 modulates chromatin accessibility to regulate estrogen receptor alpha (ER) binding and ER target gene expression in luminal breast cancer cells.

Common genetic variants in the repressive GATA-family transcription factor (TF) TRPS1 locus are associated with breast cancer risk, and luminal breast cancer cell lines are particularly sensitive to TRPS1 knockout. We introduced an inducible degron tag into the native TRPS1 locus within a luminal breast cancer cell line to identify the direct targets of TRPS1 and determine how TRPS1 mechanistically regulates gene expression. We acutely deplete over 80 percent of TRPS1 from chromatin within 30 minutes of inducing degradation. We find that TRPS1 regulates transcription of hundreds of genes, including those related to estrogen signaling. TRPS1 directly regulates chromatin structure, which causes estrogen receptor alpha (ER) to redistribute in the genome. ER redistribution leads to both repression and activation of dozens of ER target genes. Downstream from these primary effects, TRPS1 depletion represses cell cycle-related gene sets and reduces cell doubling rate. Finally, we show that high TRPS1 activity, calculated using a gene expression signature defined by primary TRPS1-regulated genes, is associated with worse breast cancer patient prognosis. Taken together, these data suggest a model in which TRPS1 modulates the genomic distribution of ER, both activating and repressing transcription of genes related to cancer cell fitness.

A prospective study of circulating estrogen in oral leukoplakia and oral squamous cell carcinoma

ABSTRACT Background: Reports suggested that hormone replacement therapy decreased the incidence of squamous cell carcinoma (SCC) of the oral cavity. Aim: The aim of this study was to analyze and quantify the serum 17β-estradiol (E2) level by chemiluminescence immunoassay in four groups, Group I (control group with no habit of tobacco and areca), Group II (control group with a habit of tobacco and areca), Group III (potentially malignant disorder—leukoplakia), and Group IV (oral squamous cell carcinoma (OSCC)). It was the first study to evaluate E2 in four study groups with and without the habit of tobacco. Method: The serum analysis was carried out in Cobas e411 analyzer by electrochemiluminescence immunoassay analysis. Results: As per the Kruskal–-Wallis test, statistically significant rise in estradiol levels in Group IV as in comparison to Group III as compared with Groups II and I. Conclusion: This study proved that irrespective of the gender bias, the female sex hormone, estradiol levels were significantly raised in OSCC patients. This study suggests that E2 may play a vital role in determining the patient prognosis in OSCC with tobacco habit. The confounding results of this preliminary study opened up new advents emphasizing the role of E2 in OSCC. The role of E2 in estrogen receptor regulation can also be a subject of study for targeted therapies in improving the patient’s prognosis.

Secoisolariciresinol diglucoside regulates estrogen receptor expression to ameliorate OVX-induced osteoporosis

ObjectiveSecoisolariciresinol diglucoside (SDG) is a phytoestrogen that has been reported to improve postmenopausal osteoporosis (PMOP) caused by estrogen deficiency. In our work, we aimed to investigate the mechanism of SDG in regulating the expressions of ERs on PMOP model rats.MethodsOvariectomization (OVX) was used to establish PMOP model in rats. The experiment was allocated to Sham, OVX, SDG and raloxifene (RLX) groups. After 12-week treatment, micro-CT was used to detect the transverse section of bone. Hematoxylin and Eosin staining and Safranine O-Fast Green staining were supplied to detect the femur pathological morphology of rats. Estradiol (E2), interleukin-6 (IL-6), bone formation and bone catabolism indexes in serum were detected using ELISA. Alkaline phosphatase (ALP) staining was used to detect the osteogenic ability of chondrocytes. Immunohistochemistry and Western blot were applied to detect the protein expressions of estrogen receptors (ERs) in the femur of rats.ResultsCompared with the OVX group, micro-CT results showed SDG could lessen the injury of bone and improve femoral parameters, including bone mineral content (BMC) and bone mineral density (BMD). Pathological results showed SDG could reduce pathological injury of femur in OVX rats. Meanwhile, SDG decreased the level of IL-6 and regulated bone formation and bone catabolism indexes. Besides, SDG increased the level of E2 and conversed OVX-induced decreased the expression of ERα and ERβ.ConclusionThe treatment elicited by SDG in OVX rats was due to the reduction of injury and inflammation and improvement of bone formation index, via regulating the expression of E2 and ERs.

The PAPSS1 gene is a modulator of response to cisplatin by regulating estrogen receptor alpha signaling activity in ovarian cancer cells

BackgroundCancer cells may develop resistance to cisplatin by various mechanisms. Yet, the exact mechanism of cisplatin in ovarian cancer remains unclear. Recent studies have shown that 3’-phospoadenosine 5’-phosphosulfate synthase 1 (PAPSS1) inhibition combined with low-dose cisplatin increases DNA damage. The aim of this study was to determine the value of targeting PAPSS1 as a cisplatin modulator in epithelial ovarian cancer (EOC).ResultsIncreased expression of PAPSS1 was observed in both EOC cells and tissues. Also, its higher nuclear expression was distinctly associated with FIGO (The International Federation of Gynecology and Obstetrics) stage, histological subtype, metastasis, and recurrence. Down-regulation of the PAPSS1 gene increased the cisplatin sensitivity of EOC in vitro and in vivo. Expression of PAPSS1 was negatively correlated with estrogen receptor α (ERα) in EOC. Also, low nuclear PAPSS1 and high nuclear ERα expression in EOC were associated with longer overall survival and progression-free survival in all ovarian cancer and ovarian cancer patients who received platinum-based chemotherapy. PAPSS1 silencing increased the activity of ERα-signaling in EOC cells, thus sensitizing tumors to cisplatin.ConclusionsThese findings characterize a novel interplay between PAPSS1-mediated sulfation and ERα-signaling in EOC cisplatin resistance. PAPSS1 may be exploited as a cisplatin-sensitizing therapeutic target.

Silibinin protects GLUTag cells from PA-induced injury via suppressing endoplasmic reticulum stress

ABSTRACT Silibinin is a natural flavonoid with anti-diabetic activity. Glucagon-like peptide−1 (GLP−1), an intestinal hormone mainly secreted from L cells, which regulates insulin production and sensitivity, appears to be a potential therapeutic strategy for T2DM. The current study aims to determine the protective effect of silibinin against palmitic acid (PA)-induced damage in GLUTag cells. The results revealed that PA triggered endoplasmic reticulum (ER) stress and apoptosis in GLUTag cells, while silibinin attenuated PA-induced lipotoxicity. Based on the estrogen-like effects of silibinin and the role of estrogen receptors in regulating glycolipid metabolism, the involvement of estrogen receptors in the protective effects of silibinin in GLUTag cells was further investigated. The results showed that estrogen receptor α- and β-specific inhibitors reversed the inhibitory impact of silibinin on ER stress. Our study demonstrated that silibinin protects GLUTag cells from PA-induced injury by decreasing ER stress under the regulation of estrogen receptors α and β.

Molecular basis and dual ligand regulation of tetrameric estrogen receptor α/14-3-3ζ protein complex

Therapeutic strategies targeting nuclear receptors (NRs) beyond their endogenous ligand binding pocket have gained significant scientific interest driven by a need to circumvent problems associated with drug resistance and pharmacological profile. The hub protein 14-3-3 is an endogenous regulator of various NRs, providing a novel entry point for small molecule modulation of NR activity. Exemplified, 14-3-3 binding to the C-terminal F-domain of the estrogen receptor alpha (ERα), and small molecule stabilization of the ERα/14-3-3ζ protein complex by the natural product Fusicoccin A (FC-A), was demonstrated to downregulate ERα-mediated breast cancer proliferation. This presents a novel drug discovery approach to target ERα; however, structural and mechanistic insights into ERα/14-3-3 complex formation are lacking. Here, we provide an in-depth molecular understanding of the ERα/14-3-3ζ complex by isolating 14-3-3ζ in complex with an ERα protein construct comprising its ligand-binding domain (LBD) and phosphorylated F-domain. Bacterial co-expression and co-purification of the ERα/14-3-3ζ complex, followed by extensive biophysical and structural characterization, revealed a tetrameric complex between the ERα homodimer and the 14-3-3ζ homodimer. 14-3-3ζ binding to ERα, and ERα/14-3-3ζ complex stabilization by FC-A, appeared to be orthogonal to ERα endogenous agonist (E2) binding, E2-induced conformational changes, and cofactor recruitment. Similarly, the ERα antagonist 4-hydroxytamoxifen inhibited cofactor recruitment to the ERα LBD while ERα was bound to 14-3-3ζ. Furthermore, stabilization of the ERα/14-3-3ζ protein complex by FC-A was not influenced by the disease-associated and 4-hydroxytamoxifen resistant ERα-Y537S mutant. Together, these molecular and mechanistic insights provide direction for targeting ERα via the ERα/14-3-3 complex as an alternative drug discovery approach.

Perfluorinated iodine alkanes promote the differentiation of mouse embryonic stem cells by regulating estrogen receptor signaling

Investigating the development toxicity of perfluorinated iodine alkanes (PFIs) is critical, given their estrogenic effects through binding with estrogen receptors (ERs). In the present study, two PFIs, including dodecafluoro-1,6-diiodohexane (PFHxDI) and tridecafluorohexyl iodide (PFHxI), with binding preference to ERα and ERβ, respectively, were selected to evaluate their effects on proliferation and differentiation of the mouse embryonic stem cells (mESCs). The results revealed that, similar to E2, 50 µmol/L PFHxDI accelerated the cell proliferation of the mESCs. The PFI stimulation at the exposure concentrations of 2–50 µmol/L promoted the differentiation of the mESCs as characterized by the upregulation of differentiation-related biomarkers (i.e., Otx2 and Dnmt3β) and downregulation of pluripotency genes (i.e., Oct4, Nanog, Sox2, Prdm14 and Rex1). Comparatively, PFHxDI exhibited higher induction effect on the differentiation of the mESCs than did PFHxI. The tests on ER signaling indicated that both PFI compounds induced exposure concentration-dependent expressions of ER signaling-related biomarkers (i.e., ERα, ERβ and Caveolin-1) in the mESCs, and the downstream ER responsive genes (i.e., c-fos, c-myc and c-jun) well responded to PFHxI stimulation. The role of ER in PFI-induced effects on the mESCs was further validated by the antagonistic experiments using an ER inhibitor (ICI). The findings demonstrated that PFIs triggered ER signaling, and perturbed the differentiation program of the mESCs, causing the potential health risk during early stage of development.

The chronification mechanism of orofacial inflammatory pain: Facilitation by GPER1 and microglia in the rostral ventral medulla.

Chronic orofacial pain is a common and incompletely defined clinical condition. The role of G protein-coupled estrogen receptor 1 (GPER1) as a new estrogen receptor in trunk and visceral pain regulation is well known. Here, we researched the role of GPER1 in the rostral ventral medulla (RVM) during chronic orofacial pain. A pain model was established where rats were injected in the temporomandibular joint with complete Freund's adjuvant (CFA) to simulate chronic orofacial pain. Following this a behavioral test was performed to establish pain threshold and results showed that the rats injected with CFA had abnormal pain in the orofacial regions. Additional Immunostaining and blot analysis indicated that microglia were activated in the RVM and GPER1 and c-Fos were significantly upregulated in the rats. Conversely, when the rats were injected with G15 (a GPER1 inhibitor) the abnormal pain the CFA rats were experiencing was alleviated and microglia activation was prevented. In addition, we found that G15 downregulated the expression of phospholipase C (PLC) and protein kinase C (PKC), inhibited the expression of GluA1, restores aberrant synaptic plasticity and reduces the overexpression of the synapse-associated proteins PSD-95 and syb-2 in the RVM of CFA rats. The findings indicate that GPER1 mediates chronic orofacial pain through modulation of the PLC-PKC signal pathway, sensitization of the RVM region and enhancement of neural plasticity. These results of this study therefore suggest that GPER1 may serve as a potential therapeutic target for chronic orofacial pain.

Extracellular Acidosis Differentially Regulates Estrogen Receptor β-Dependent EMT Reprogramming in Female and Male Melanoma Cells

Clinical outcomes of melanoma patients pointed out a gender disparity that supports a correlation between sex hormone activity on estrogen receptors (ER) and melanoma development and progression. Here, we found that the epithelial-to-mesenchymal transition (EMT) of melanoma cells induced by extracellular acidosis, which is a crucial hallmark of solid cancers, correlates with the expression of ERβ, the most representative ER on melanoma cells. Extracellular acidosis induces an enhanced expression of ERβ in female cells and EMT markers remain unchanged, while extracellular acidosis did not induce the expression of ERβ in male cells and EMT was strongly promoted. An inverse relationship between ERβ expression and EMT markers in melanoma cells of different sex exposed to extracellular acidosis was revealed by two different technical approaches: florescence-activated cell sorting of high ERβ expressing cell subpopulations and ERβ receptor silencing. Finally, we found that ERβ regulates EMT through NF-κB activation. These results demonstrate that extracellular acidosis drives a differential ERβ regulation in male and female melanoma cells and that this gender disparity might open new perspectives for personalized therapeutic approaches.

MOF negatively regulates estrogen receptor α signaling via CUL4B-mediated protein degradation in breast cancer.

Estrogen receptor α (ERα) is the dominant tumorigenesis driver in breast cancer (BC), and ERα-positive BC (ERα+ BC) accounts for more than two-thirds of BC cases. MOF (males absent on the first) is a highly conserved histone acetyltransferase that acetylates lysine 16 of histone H4 (H4K16) and several non-histone proteins. Unbalanced expression of MOF has been identified, and high MOF expression predicted a favorable prognosis in BC. However, the association of MOF with ERα and the regulatory mechanisms of MOF in ERα signaling remain elusive. Our study revealed that the expression of MOF is negatively correlated with that of ERα in BC. In ERα+ BC cells, MOF overexpression downregulated the protein abundance of ERα in both cytoplasm and nucleus, thus attenuating ERα-mediated transactivation as well as cellular proliferation and in vivo tumorigenicity of BC cells. MOF promoted ERα protein degradation through CUL4B-mediated ubiquitin–proteasome pathway and induced HSP90 hyperacetylation that led to the loss of chaperone protection of HSP90 to ERα. We also revealed that suppression of MOF restored ERα expression and increased the sensitivity of ERα-negative BC cells to tamoxifen treatment. These results provide a new insight into the tumor-suppressive role of MOF in BC via negatively regulating ERα action, suggesting that MOF might be a potential therapeutic target for BC.

MiR-489 Confines Uncontrolled Estrogen Signaling through a Negative Feedback Mechanism and Regulates Tamoxifen Resistance in Breast Cancer

Approximately 75% of diagnosed breast cancer tumors are estrogen-receptor-positive tumors and are associated with a better prognosis due to response to hormonal therapies. However, around 40% of patients relapse after hormonal therapies. Genomic analysis of gene expression profiles in primary breast cancers and tamoxifen-resistant cell lines suggested the potential role of miR-489 in the regulation of estrogen signaling and development of tamoxifen resistance. Our in vitro analysis showed that loss of miR-489 expression promoted tamoxifen resistance, while overexpression of miR-489 in tamoxifen-resistant cells restored tamoxifen sensitivity. Mechanistically, we found that miR-489 is an estrogen-regulated miRNA that negatively regulates estrogen receptor signaling by using at least the following two mechanisms: (i) modulation of the ER phosphorylation status by inhibiting MAPK and AKT kinase activities; (ii) regulation of nuclear-to-cytosol translocation of estrogen receptor α (ERα) by decreasing p38 expression and consequently ER phosphorylation. In addition, miR-489 can break the positive feed-forward loop between the estrogen-Erα axis and p38 MAPK in breast cancer cells, which is necessary for its function as a transcription factor. Overall, our study unveiled the underlying molecular mechanism by which miR-489 regulates an estrogen signaling pathway through a negative feedback loop and uncovered its role in both the development of and overcoming of tamoxifen resistance in breast cancers.

Effects of hypothyroidism on the female pancreas involve the regulation of estrogen receptors

This study aimed to investigate the impact of short-time hypothyroidism on the expression of aromatase, estrogen receptors (ERα, β), and GPR30 in the pancreas of female rabbits. The formation of new islets and the expression of insulin, GLUT4, and lactate dehydrogenase (LDH) were also analyzed. This purpose is based on actions that thyroid hormones and estrogens have on β-cells differentiation, acinar cell function, and insulin secretion. Twelve Chinchilla-breed adult virgin female rabbits were divided into control (n = 6) and hypothyroid (n = 6; methimazole 10 mg/kg for 30 days) groups. In the complete pancreas, expressions of aromatase and estrogen receptors, as well as proinsulin, GLUT4, and LDH were determined by western blot. Characteristics of islets were measured in slices of the pancreas with immunohistochemistry for insulin. Islet and acinar cells express aromatase, ERα, ERβ, and GPR30. Hypothyroidism increased the expression of ERα and diminished that for aromatase, ERβ, and GPR30 in the pancreas. It also promoted a high number of extra small islets (new islets) and increased the expression of proinsulin and GLUT4 in the pancreas. Our results show that actions of thyroid hormones and estrogens on β-cells neogenesis, acinar cell function, and synthesis and secretion of insulin are linked. Thus, the effects of hypothyroidism on the pancreas could include summatory actions of thyroid hormones plus estrogens. Our findings indicate the importance of monitoring estrogen levels and actions on the pancreas of hypothyroid women, particularly when serum estrogen concentrations are affected such as menopausal, pregnant, and those with contraceptive use.

Pharmacological Properties to Pharmacological Insight of Sesamin in Breast Cancer Treatment: A Literature-Based Review Study.

The use of dietary phytochemical rather than conventional therapies to treat numerous cancers is now a well-known approach in medical science. Easily available and less toxic dietary phytochemicals present in plants should be introduced in the list of phytochemical-based treatment areas. Sesamin, a natural phytochemical, may be a promising chemopreventive agent aiming to manage breast cancer. In this study, we discussed the pharmacological properties of sesamin that determine its therapeutics opportunity to be used in breast cancer treatment and other diseases. Sesamin is available in medicinal plants, especially in Sesamum indicum, and is easily metabolized by the liver. To better understand the antibreast cancer consequence of sesamin, we postulate some putative pathways related to the antibreast cancer mechanism: (1) regulation of estrogen receptor (ER-α and ER-β) activities, (2) suppressing programmed death-ligand 1 (PD-L1) overexpression, (3) growth factor receptor inhibition, and (4) some tyrosine kinase pathways. Targeting these pathways, sesamin can modulate cell proliferation, cell cycle arrest, cell growth and viability, metastasis, angiogenesis, apoptosis, and oncogene inactivation in various in vitro and animal models. Although the actual tumor intrinsic signaling mechanism targeted by sesamin in cancer treatment is still unknown, this review summarized that this phytoestrogen suppressed NF-κB, STAT, MAPK, and PIK/AKT signaling pathways and activated some tumor suppressor protein in numerous breast cancer models. Cotreatment with γ-tocotrienol, conventional drugs, and several drug carriers systems increased the anticancer potentiality of sesamin. Furthermore, sesamin exhibited promising pharmacokinetics properties with less toxicity in the bodies. Overall, the shreds of evidence highlight that sesamin can be a potent candidate to design drugs against breast cancer. So, like other phytochemicals, sesamin can be consumed for better therapeutic advantages due to having the ability to target a plethora of molecular pathways until clinically trialed standard drugs are not available in pharma markets.

ERα, but not ERβ and GPER, Mediates Estradiol-Induced Secretion of TSH in Mouse Pituitary.

Although estradiol (E2) plays a critical role in the promotion of pituitary development and in the regulation of various pituitary hormones, its effects on the thyroid-stimulating hormone (TSH) remain unaddressed. The actions of E2 are mediated by two classical nuclear estrogen receptors α (ERα) and β (ERβ) and the G protein-coupled estrogen receptor (GPER). However, the types of estrogen receptor involvement in the regulation of thyrotropes are still limited. In this study, we demonstrate that ERα, but not ERβ and GPER, is localized to thyrotropes in the pituitary of female mouse. In agreement with the presence of ERα in thyrotropes, E2 was shown to stimulate TSH release in vitro from primary culture of female mouse pituitary cells. PPT, a ERα-selective agonist, but not DPN (a ERβ-selective agonist) and G-1 (a GPER-selective agonist), was shown to stimulate TSH release in mouse pituitary cells. This effect could be prevented by the specific ER antagonist fulvestrant and the selective ERα antagonist MPP. The findings of this study suggest that E2 may bind to ERα to trigger TSH release and provide novel information on the differential regulation of multiple estrogen receptors in the pituitary.

Expression and regulation of estrogen receptor 2 and its coregulators in mouse granulosa cells.

The cooperative effects of estrogen and oocyte-derived paracrine factors (ODPFs) play critical roles in the normal development of ovarian follicles; however, the mechanism underlying this cooperation has not been well studied. The present study aimed to determine whether ODPFs affect estrogen signaling by regulating the expression of estrogen receptor (ESR) and its coregulators in mouse granulosa cells. Some transcripts encoding ESR coregulators were differentially expressed between cumulus and mural granulosa cells (MGCs). The transcript levels of ESR coregulators, including nuclear receptor corepressor 1 and activator 2, in cumulus cells were significantly suppressed by ODPFs; however, they increased when cumulus cell-oocyte complexes were treated with the transforming growth factor beta receptor I inhibitor, SB431542. Moreover, MGCs exhibited significantly higher ESR2 protein and transcript levels than those in cumulus cells. ODPFs promoted Esr2 expression in cumulus cells but had no effect on that in MGCs. Overall, regulation of the expression of ESR2 and its coregulators in cumulus cells by oocytes seems to be one of the mechanisms underlying estrogen-oocyte cooperation in well-developed antral follicles in mice.

Defective Signalling of the BRCA1 Neighbouring gene, NBR2, leads to ER-? Negative tumours in breast cancer xenograft mouse models

Majority of breast and ovarian cancer treatment modalities are based on endocrine therapies like antiestrogens which are dependent on the hormone receptor status of tumours. Although BRCA1 is a major regulator of Estrogen Receptor (ER-α), BRCA1 mutations are largely limited to hereditary cases. Here, we show the role of NBR2 (neighbour of BRCA1) in regulating ER-α. We demonstrate a positive correlation between NBR2 & ESR1 in TCGA datasets. Further, the study revealed that shRNA-mediated knockdown of NBR2 led to the downregulation of ER-α in breast cancer cells, MCF7. Finally, the downregulation of ER-α in NBR2 knockdown xenograft tumours (in female NSG mice), which showed higher invasive properties than wild type tumours was demonstrated. Thus, we concluded that in ER-α negative tumours with NBR2 deficiency, biguanides such as metformin and phenformin, which are reported to have a better efficacy under NBR2 deficient conditions, could serve as more suitable alternatives to antiestrogens.

Perfluorinated Iodine Alkanes Promote the Differentiation of Mouse Embryonic Stem Cells by Regulating Estrogen Receptor Signaling

Perfluorinated Iodine Alkanes Promote the Differentiation of Mouse Embryonic Stem Cells by Regulating Estrogen Receptor Signaling