Estrogen Receptor Modulators Research Articles

Oestrogen receptor β ligand acts on CD11c+ cells to mediate protection in experimental autoimmune encephalomyelitis

Oestrogen treatments are neuroprotective in a variety of neurodegenerative disease models. Selective oestrogen receptor modifiers are needed to optimize beneficial effects while minimizing adverse effects to achieve neuroprotection in chronic diseases. Oestrogen receptor beta (ERβ) ligands are potential candidates. In the multiple sclerosis model chronic experimental autoimmune encephalomyelitis, ERβ-ligand treatment is neuroprotective, but mechanisms underlying this neuroprotection remain unclear. Specifically, whether there are direct effects of ERβ-ligand on CD11c+ microglia, myeloid dendritic cells or macrophages in vivo during disease is unknown. Here, we generated mice with ERβ deleted from CD11c+ cells to show direct effects of ERβ-ligand treatment in vivo on these cells to mediate neuroprotection during experimental autoimmune encephalomyelitis. Further, we use bone marrow chimeras to show that ERβ in peripherally derived myeloid cells, not resident microglia, are the CD11c+ cells mediating this protection. CD11c+ dendritic cell and macrophages isolated from the central nervous system of wild-type experimental autoimmune encephalomyelitis mice treated with ERβ-ligand expressed less iNOS and T-bet, but more IL-10, and this treatment effect was lost in mice with specific deletion of ERβ in CD11c+ cells. Also, we extend previous reports of ERβ-ligand’s ability to enhance remyelination through a direct effect on oligodendrocytes by showing that the immunomodulatory effect of ERβ-ligand acting on CD11c+ cells is necessary to permit the maturation of oligodendrocytes. Together these results demonstrate that targeting ERβ signalling pathways in CD11c+ myeloid cells is a novel strategy for regulation of the innate immune system in neurodegenerative diseases. To our knowledge, this is the first report showing how direct effects of a candidate neuroprotective treatment on two distinct cell lineages (bone marrow derived myeloid cells and oligodendrocytes) can have complementary neuroprotective effects in vivo.awx315media15688130498001.

Treatment of Girls and Boys with McCune-Albright Syndrome with Precocious Puberty - Update 2017.

The most common endocrinopathy associated with McCune-Albright Syndrome (MAS) is peripheral precocious puberty (PP) which occurs far more often in girls than in boys. We will discuss the latest advancements in the treatment of precocious puberty in MAS that have been achieved during the past 10 years. However, due to the rarity of the condition and the heterogeneity of the disease, research in this field is limited particularly in regards to treatment in boys. In girls, a period of watchful waiting is recommended prior to initiating therapy due to extreme variability in the clinical course. This article will review in detail current pharmacologic treatment in girls, which typically consists of either inhibiting estrogen production or blocking estrogen action at the level of the end-organ. The two treatments with the most evidence at this time are Tamoxifen (which is an estrogen receptor modulator) and Letrozole (which is a 3rd generation aromatase inhibitor). This article will also review the current treatment strategies in boys which typically include using an androgen receptor blocker and an aromatase inhibitor. Due to the rarity of the condition, large multicenter collaborative studies are needed to further investigate efficacy and safety with the goal of establishing the gold standard for treatment of PP in children with MAS.

Identification of a Raloxifene Analog That Promotes AhR-Mediated Apoptosis in Cancer Cells.

We previously reported that raloxifene, an estrogen receptor modulator, is also a ligand for the aryl hydrocarbon receptor (AhR). Raloxifene induces apoptosis in estrogen receptor-negative human cancer cells through the AhR. We performed structure–activity studies with seven raloxifene analogs to better understand the structural requirements of raloxifene for induction of AhR-mediated transcriptional activity and apoptosis. We identified Y134 as a raloxifene analog that activates AhR-mediated transcriptional activity and induces apoptosis in MDA-MB-231 human triple negative breast cancer cells. Suppression of AhR expression strongly reduced apoptosis induced by Y134, indicating the requirement of AhR for Y134-induced apoptosis. Y134 also induced apoptosis in hepatoma cells without having an effect on cell cycle regulation. Toxicity testing on zebrafish embryos revealed that Y134 has a significantly better safety profile than raloxifene. Our studies also identified an analog of raloxifene that acts as a partial antagonist of the AhR, and is capable of inhibiting AhR agonist-induced transcriptional activity. We conclude that Y134 is a promising raloxifene analog for further optimization as an anti-cancer agent targeting the AhR.

Quantification of the Effect of Toxicants on the Intracellular Kinetic Energy and Cross-Sectional Area of Mammary Epithelial Organoids by OCT Fluctuation Spectroscopy.

The ability to assess toxicant exposures of 3D in vitro mammary models that recapitulate the tissue microenvironment can aid in our understanding of environmental exposure risk over time. Longitudinal studies of 3D model systems, however, are cumbersome and suffer from a lack of high-throughput toxicological assays. In this study, we establish a noninvasive and label-free optical coherence tomography (OCT)-based imaging platform for tracking exposure-response relationships in 3D human mammary epithelial organoid models. The OCT-based assay includes metrics that quantify organoid intracellular kinetic energy and cross-sectional area (CSA). We compare the results to those obtained using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) mitochondrial dye conversion assay. Both estrogen receptor (ER)-positive (MCF7) and ER-negative (MCF10DCIS.com) breast cell lines were studied, beginning one hour after exposure and continuing for several days. Six days of exposure to 17β-estradiol or the selective ER modulator 4-hydroxytamoxifen respectively increased or decreased MCF7 organoid CSA (p < .01), consistent with the role of estrogen signaling in ER-positive mammary epithelial cell proliferation. We also observed a significant decrease in the intracellular kinetic energy of MCF10DCIS.com organoids after 24 h of exposure to doxorubicin, a cytotoxic intercalating agent that causes DNA double-strand breaks (p < .01). MTT-based metabolic activity of MCF10DCIS.com organoids after 48 h of doxorubicin exposure decreased with dose in a similar manner as OCT-based energy metrics. These results demonstrate the feasibility of an OCT-based assay to quantify mammary epithelial cell toxicant response in vitro, noninvasively, longitudinally, and in the context of tissue microenvironments, providing a new high-throughput screening tool for toxicological studies.

Membrane delimited estrogen receptor activation protects heart against ischemic-reperfusion injury in mice with cardiac but not endothelial specific ablation of ERα

Steroid hormone receptors, such as estrogen receptors (ER) function as ligand-regulated transcription factors. However, recent data indicate that estrogen also elicits effects through binding to estrogen receptors (ER-α, ER-β and GPER) at the plasma membrane and initiating signaling. In this study, ovariectomized C57BL/6J mice were treated with estradiol (6 μg/day) or estrogen-dendrimer conjugate (EDC, a membrane delimited ER modulator) for two weeks. Ischemia-reperfusion injury was evaluated in Langendorff perfused hearts. Similar to estradiol-treated hearts, EDC treatment significantly decreased infarct size and improved post-ischemic functional recovery. EDC treatment also resulted in an increase in protein S-nitrosylation (SNO), consistent with previous studies showing a SNO role in cardioprotection. In further support of a role for SNO, inhibition of nitric oxide synthase but not soluble guanylyl cyclase blocked EDC-mediated protection. ICI182,780 (antagonist of classic ER but agonist of GPER) significantly blocked the EDC-mediated cardioprotection, suggesting EDC-induced protection is mediated by classic ER. Cardiac- or endothelial-specific (cs- or es-) ERα knockout (KO) mice were generated to test tissue-specific ERα involved in EDC protection. In cs-ERαKO mice, EDC treatment still significantly decreased infarct size and improved functional recovery similar to that found in wildtype, while protection was lost in es-ERαKO mice, suggesting an important role for endothelial ERα. In contrast to wildtype hearts, EDC treatment did not increase SNO in es-ERαKO mice. ERα but not ERβ was found significantly decreased in cs-ERαKO mice, while opposite results were found in es-ERαKO mice. Thus, loss of EDC-induced protection and SNO increase in es-ERαKO mice could also be due to significant down-regulation of cardiac ERβ/SNO signaling. In conclusion, these results demonstrated a role of activation of membrane delimited ER in cardioprotection, suggesting that EDC-like compounds could be used clinically to provide cardiovascular benefit without the classical steroid hormone side effects, such as stimulation of uterine and breast cancer.

Synthesis of prenylated flavonols and their potents as estrogen receptor modulator

Prenylated flavonols are known as phytoestrogen and have good bioactivties. However, their abundances in nature are pretty low. It is required to find an efficient synthesis technique. Icariin is a prenylated flavonol glycoside with low cost. It can be used to synthesize different prenylated flavonols. A combination of cellulase and trifluoacetic acid hydrolysis could effectively remove rhamnose and glucose from icariin. Icaritin, anhydroicaritin and wushanicaritin were the leading prenylated flavonol products. Their affinities to estrogen receptors α and β were predicted by docking study. The weak affinity of wushanicaritin indicated that prenyl hydroxylation impaired its affinity to estrogen receptor β. The prenyl cyclization led to a loss of affinity to both receptors. The interactions between icaritin and ligand binding cavity of estrogen receptor β were simulated. π-π stacking and hydrophobic forces were predicted to be the dominant interactions positioning icaritin, which induced the helix (H12) forming an activated conformation.

Biological effects of combined resveratrol and vitamin D3 on ovarian tissue

BackgroundResveratrol (3,5,4′-trihydroxy-trans-stilbene) is a natural antioxidant polyphenol able to exert a wide range of biological effect on several tissues. Despite its important beneficial properties, it has a low water solubility, which limits its therapeutic applications in humans. Resveratrol also acts as a phytoestrogen that modulates estrogen receptor (ER)-mediated transcription. In addition, it has been shown that ovarian tissues benefit greatly from vitamin D3, which exerts its beneficial effects through VDR receptors.The aim was to evaluate the cooperative effects of resveratrol combined with vitamin D3 on ovarian cells and tissues and some other organs as well. Moreover, the modulation of specific intracellular pathways involving ER and VDR receptors has been studied.MethodsThe experiments were performed both in vitro and in vivo, to analyze cell viability, radical oxygen species production, signal transductions through Western Blot, and resveratrol quantification by HPLC.ResultsCell viability, radical oxygen species production, and intracellular pathways have been studied on CHO-K1 cells. Also, the relative mechanism activated following oral intake in female Wistar rats as animal model was investigated, evaluating bioavailability, biodistribution and signal transduction in heart, kidney, liver and ovarian tissues. Both in in vitro and in vivo experiments, resveratrol exerts more evident effects when administered in combination with vitD in ovarian cells, showing a common biphasic cooperative effect: The role of vitamin D3 in maintaining and supporting the biological activity of resveratrol has been clearly observed. Moreover, resveratrol plus vitamin D3 blood concentrations showed a biphasic absorption rate.ConclusionsSuch results could be used as a fundamental data for the development of new therapies for gynecological conditions, such as hot-flashes.

Breast Cancer Suppression by Progesterone Receptors Is Mediated by Their Modulation of Estrogen Receptors and RNA Polymerase III.

Greater than 50% of estrogen receptor (ER)-positive breast cancers coexpress the progesterone receptor (PR), which can directly and globally modify ER action to attenuate tumor growth. However, whether this attenuation is mediated only through PR-ER interaction remains unknown. To address this question, we assessed tumor growth in ER/PR-positive patient-derived xenograft models of breast cancer, where both natural and synthetic progestins were found to antagonize the mitogenic effects of estrogens. Probing the genome-wide mechanisms by which this occurs, we documented that chronic progestin treatment blunted ER-mediated gene expression up to 2-fold at the level of mRNA transcripts. Unexpectedly, <25% of all ER DNA binding events were affected by the same treatment. The PR cistrome displayed a bimodal distribution. In one group, >50% of PR binding sites were co-occupied by ER, with a propensity for both receptors to coordinately gain or lose binding in the presence of progesterone. In the second group, PR but not ER was associated with a large fraction of RNA polymerase III-transcribed tRNA genes, independent of hormone treatment. Notably, we discovered that PR physically associated with the Pol III holoenzyme. Select pre-tRNAs and mature tRNAs with PR and POLR3A colocalized at their promoters were relatively decreased in estrogen + progestin-treated tumors. Our results illuminate how PR may indirectly impede ER action by reducing the bioavailability of translational molecules needed for tumor growth. Cancer Res; 77(18); 4934-46. ©2017 AACR.

The Woman's Heart: Insights into New Potential Targeted Therapy.

Cardiovascular disease is an increasingly common cause of death in women. There is as yet no consensus on the analysis of cardiovascular risk factors with regard to the specific, personalised treatment of pre- and post-menopausal women. Clinically significant cardioprotective and antiremodelling effects have been observed in animal and human studies exploring chronic inhibition of phosphodiesterase type 5 (PDE5). The relationship between the heart, estrogens and PDE5 inhibitors (PDE5is) remains unclear. Experimental data suggest potential beneficial effects on cardiac geometry, function, endothelial function and microvascular coronary flow in women. It was recently postulated that the efficacy of PDE5is is estrogen-dependent in female heart disease. A registered randomised, placebo-controlled study, RECOGITO (NCT01803828), aimed at identifying the genderspecific efficacy of long-term PDE5 inhibition in diabetic cardiomyopathy, is currently recruiting patients. Estrogen receptor modulation could be a new promising approach to heart protection via PDE5is. PDE5is could be indicated as a gender-oriented strategy in modulated cardiac dysfunction and remodelling and in cardiac risk factors for selected cardiovascular diseases.

Tamoxifen gynecological side effects

Prospective comparative study done in basrah maternity and child hospital over a period of two years from 2002- 2004 , on breast cancer patients treated with tamoxifen which is estrogen receptors modulators with paradoxical effects ( agonist on some tissue and antagonist on others. This study aimed To compare side effect of tamoxifen on both studied groups Premenopausal and postmenopausal.This study included96 Symptomatic pre and postmenopausal breast cancer treated patients with tamoxifen assassed by history and then examination was performedThen endometrium assessed by transabdominal ultrasound to check thickness then almost all patients subjected to endometrial biopsy under general anesthesia, about 45.8% of patients between 50-60 years of age 41.6% of patients had advanced stages of cancer , vaginal bleeding which is the most common symptom symptoms presented in 68.7% ,while 22.8% , 8.28% had vaginal discharge and pain respectively.ultrasound findings showed 22.9% endometrial thickness less than 6mm , 41.6% endometrial thickness 1 cm and more ,10.3% showed polyps and fibroid . no statistical difference between pre and postmenopausal inUSS findings with p value = 7.81, x2= 13.7, df=321.2% showed atrophic endometrium, 16.9% showed endometrial hyperplasia , bulk 44.6% showed non secretory ( proliferative) , with no cases of endometrial carcinoma . No, statistical difference between pre and postmenopausal findingsP value = 9.49 , x2 8.652 , df= 4 .In conclusion the main sharing symptoms in both groups was vaginal bleeding, USS had a poor predictive value in detecting changes in both studied groupOur study did not confirm risk of endometrial carcinoma , with no statistical difference in risk of hyperplasia between pre and postmenopausal studied groups.

Epigenetic Mechanisms of Tamoxifen Resistance in Luminal Breast Cancer.

Breast cancer is one of the most common cancers and the second leading cause of cancer death in the United States. Estrogen receptor (ER)-positive cancer is the most frequent subtype representing more than 70% of breast cancers. These tumors respond to endocrine therapy targeting the ER pathway including selective ER modulators (SERMs), selective ER downregulators (SERDs) and aromatase inhibitors (AIs). However, resistance to endocrine therapy associated with disease progression remains a significant therapeutic challenge. The precise mechanisms of endocrine resistance remain unclear. This is partly due to the complexity of the signaling pathways that influence the estrogen-mediated regulation in breast cancer. Mechanisms include ER modifications, alteration of coregulatory function and modification of growth factor signaling pathways. In this review, we provide an overview of epigenetic mechanisms of tamoxifen resistance in ER-positive luminal breast cancer. We highlight the effect of epigenetic changes on some of the key mechanisms involved in tamoxifen resistance, such as tumor-cell heterogeneity, ER signaling pathway and cancer stem cells (CSCs). It became increasingly recognized that CSCs are playing an important role in driving metastasis and tamoxifen resistance. Understanding the mechanism of tamoxifen resistance will provide insight into the design of novel strategies to overcome the resistance and make further improvements in breast cancer therapeutics.

Abstract LB-299: Glucose metabolism modulator HJC0152 differentially regulates glycolytic enzymes to suppress breast carcinogenesis

Abstract Currently available preventive therapies for breast cancer (BC) are primarily based on selective estrogen receptor (ER) modulators (SERMs) to target ER signaling. However, these drugs only partially prevent ER-positive BCs (EPBCs) but not ER-negative BCs (ENBCs), rendering approximately 60% of BCs unpreventable. About half of established EPBCs respond to SERMs and aromatase inhibitors (AIs), whereas ENBCs, most of which are triple-negative BCs (TNBCs), do not respond to SERMs or AIs. To date, there is no other targeted therapy for ENBCs or nonresponsive/resistant EPBCs, presenting a pressing need of non-ER-based targets and the agents that can effectively target such targets. Dysregulated glucose and energy metabolism is critically involved in the development and progression of various cancers, however, such a role in BC development remains largely unknown, thus representing a key knowledge gap and a potential avenue for non-ER-based targeted prevention and treatment of BC. Several metabolic and biogenetic anticancer therapies have been developed, but none has progressed to clinical use owing to their limited potency or specificity and/or their undesirable drug properties, such as toxicity and poor bioavailability. We recently developed a new class of anticancer agents, including HJC0152, that target glucose and energy metabolism and thus may have promise for the prevention and treatment of BCs, particularly ENBCs and resistant EPBCs. In this study, orally active HJC0152 differentially modulates glycolytic enzymes in BC cells. HJC0152 also regulates the transcription of genes involved in glucose and mitochondrial energy metabolism, including the subunits of mitochondrial respiratory chain complexes. HJC0152 also significantly inhibits Complexes IV but increases Complex V (ATP synthase) function, while Complexes I and II function is minimally affected. Migration and invasion of MDA-MB-231 cells are significantly inhibited by HJC0152 exposure. In vivo, HJC0152 significantly blocked mammary tumor development in mouse ENBC and TNBC models via inhibiting premalignant lesions. HJC0152 also dramatically blocked the development of experimental lung macro- and micro-metastasis in mice. These results suggest that HJC0152 can reprogram/restore the dysregulated glucose metabolism by inducing specific glycolytic enzyme expression and mitochondrial respiratory chain function, likely via targeting one or more upstream signal molecule(s) that regulates glucose and energy metabolism, thereby suppressing BC development and progression. To elucidate the mechanisms and discover the oncogenic drivers that promote BC development and progression, we are employing several strategies including in silico HJC0152 function-modelling and structure-modelling analysis, Unique Polymer Technology, and HJC0152-derived tool compounds to identify the HJC0152-interacting target(s). An initial in silico analysis has resulted in 12 potential targets, including the known JAK/STAT pathway molecules and proteins important for glucose/energy metabolism for further validation studies. This work was supported by Grants P50 CA097007, and P30DA028821(JZ) from NIH, CPRIT (JZ), John Sealy Memorial Endowment Fund (JZ), DFI Seed Grants from MDACC (QS), the Prevent Cancer Foundation (QS), and the PREVENT Program from NIH/NCI (QS). Citation Format: Jiabin Dong, Dengfeng Li, Hyejin Kim, Hong Wang, Zhi Zheng, Ziwei Zhang, Na Ye, Haiying Chen, Jia Zhou, Qiang Shen. Glucose metabolism modulator HJC0152 differentially regulates glycolytic enzymes to suppress breast carcinogenesis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr LB-299. doi:10.1158/1538-7445.AM2017-LB-299

Phytochemicals Targeting Estrogen Receptors: Beneficial Rather Than Adverse Effects?

In mammals, the effects of estrogen are mainly mediated by two different estrogen receptors, ERα and ERβ. These proteins are members of the nuclear receptor family, characterized by distinct structural and functional domains, and participate in the regulation of different biological processes, including cell growth, survival and differentiation. The two estrogen receptor (ER) subtypes are generated from two distinct genes and have partially distinct expression patterns. Their activities are modulated differently by a range of natural and synthetic ligands. Some of these ligands show agonistic or antagonistic effects depending on ER subtype and are described as selective ER modulators (SERMs). Accordingly, a few phytochemicals, called phytoestrogens, which are synthesized from plants and vegetables, show low estrogenic activity or anti-estrogenic activity with potentially anti-proliferative effects that offer nutraceutical or pharmacological advantages. These compounds may be used as hormonal substitutes or as complements in breast cancer treatments. In this review, we discuss and summarize the in vitro and in vivo effects of certain phytoestrogens and their potential roles in the interaction with estrogen receptors.

The olive oil phenolic (-)-oleocanthal modulates estrogen receptor expression in luminal breast cancer in vitro and in vivo and synergizes with tamoxifen treatment

Luminal breast cancer represents a therapeutic challenge in terms of aggressive disease and emerging resistance to targeted therapy. (-)-Oleocanthal has demonstrated anticancer activity in multiple human cancers. The goal of this study was to explore the effect of (-)-oleocanthal treatment on growth of luminal breast cancer cells and to examine the effect of combination of (-)-oleocanthal with tamoxifen. Results showed that (-)-oleocanthal inhibited growth of BT-474, MCF-7, and T-47D human breast cancer cells in mitogen-free media with IC50 values of 32.7, 24.07, and 80.93µM, respectively. Similarly, (-)-oleocanthal suppressed growth of BT-474, MCF-7, and T-47D cells in 17β-estradiol-supplemented media with IC50 values of 22.28, 20.77, and 83.91µM, respectively. Combined (-)-oleocanthal and tamoxifen treatments resulted in a synergistic growth inhibition of BT-474, MCF-7, and T-47D cells with combination index values of 0.65, 0.61, and 0.53 for each cell line, respectively. In-silico docking studies indicated high degree of overlapping for the binding of (-)-oleocanthal and 17β-estradiol to estrogen receptors, while (-)-oleocanthal and tamoxifen have distinguished binding modes. Treatment with 5mg/kg or 10mg/kg (-)-oleocanthal resulted in 97% inhibition of tumor growth in orthotopic athymic mice bearing BT-474 tumor xenografts compared to vehicle-treated animals. (-)-Oleocanthal treatment reduced total levels of estrogen receptors in BT-474 cells both in vitro and in vivo. Collectively, (-)-oleocanthal showed a potential beneficial effect in suppressing growth of hormone-dependent breast cancer and improving sensitivity to tamoxifen treatment. These findings provide rational for evaluating the effect of (-)-oleocanthal in combination with endocrine treatments in luminal breast cancer.

Baicalein, unlike 4-hydroxytamoxifen but similar to G15, suppresses 17β-estradiol-induced cell invasion, and matrix metalloproteinase-9 expression and activation in MCF-7 human breast cancer cells.

Estrogen performs an important role in the growth and development of breast cancer. There are at least three major receptors, including estrogen receptor (ER)α and β, and G protein-coupled receptor 30 (GPR30), which mediate the actions of estrogen through using transcriptional and rapid non-genomic signaling pathways. Flavonoids have been considered candidates for chemopreventive agents in breast cancer. Baicalein, the primary flavonoid derived from the root of Scutellaria baicalensis Georgi, has been reported to exert an anti-estrogenic effect. In the present study, the effects of baicalein on 17β-estradiol (E2)-induced cell invasion, and matrix metalloproteinase-9 (MMP-9) expression and activation were investigated. Furthermore, its effects were compared with that of the active form of the ER modulator tamoxifen 4-hydroxytamoxifen (OHT) and the GPR30 antagonist G15 in ERα- and GPR30-positive MCF-7 breast cancer cells. The results demonstrated that OHT failed to prevent E2-induced cell invasion, upregulation and proteolytic activity of MMP-9. However, baicalein was able to significantly suppress these E2-induced effects. Furthermore, E2-stimulated invasion, and MMP-9 expression and activation were significantly attenuated following G15 treatment. In addition, baicalein significantly inhibited G-1, a specific GPR30 agonist, induced invasion, and reduced G-1 promoted expression and activity of MMP-9, consistent with effects of G15. The results of the present study suggest that baicalein is a therapeutic candidate for GPR30-positive breast cancer treatment, and besides ERα targeting the GPR30 receptor it may achieve additional therapeutic benefits in breast cancer.

Treatment with Standard and Low Dose of Conjugated Equine Estrogen Differentially Modulates Estrogen Receptor Expression and Response to Angiotensin II in Mesenteric Venular Bed of Surgically Postmenopausal Hypertensive Rats.

Standard hormone therapy for menopausal women [conjugated equine estrogen (CEE) 0.625 mg] has been associated with increased risk of venous thrombosis. Regimens containing a lower CEE dose (0.30 mg) have been used clinically to decrease side effects of supraphysiologic doses of estrogen. In this study, we determined the effects of standard (SD) and low dose (LD) of CEE on venular function in ovariectomized (OVX) spontaneously hypertensive rats (SHR). Contractions by angiotensin-II (Ang-II 10 μM) in perfused mesenteric venular bed were markedly increased in OVX (21.5 ± 1.3 mmHg) compared with Sham (14.7 ± 1.1 mm Hg, P < 0.05). CEE-SD did not modify Ang-II responses in OVX, whereas CEE-LD restored Ang-II contraction to Sham levels. Endothelial nitric oxide synthase (eNOS) inhibition by L-NAME increased Ang-II contractions in Sham and CEE-LD and was without effect in venules of OVX SHR and CEE-SD. In OVX there was decreased NO generation in association with diminished eNOS phosphorylation and increased O2- generation in the venular wall. CEE-LD reverted the deleterious effects of ovariectomy. Although CEE-SD augmented eNOS phosphorylation in OVX, it was unable to increase NO levels, probably owing to its inability to reduce O2- Distinct effects by CEE-SD and CEE-LD parallel the differential modulation of Ang-II and estrogen receptors. Compared with Sham, CEE-LD increases Ang II receptor type 2, whereas CEE-SD modified ERβ expression in the venous bed. Interestingly, both CEE doses increased G protein-coupled estrogen receptor in OVX. Our data suggest that estrogen dose is an important factor for venous function. Although CEE-LD reversed deleterious effects of OVX, CEE-SD showed null effects despite its ability to increase eNOS activity.

Comprehensive genomic sequencing for triple negative breast cancer in Japan.

e23122 Background: Breast cancer is the leading cancer among women both in US and Japan. Triple negative breast cancer (TNBC) is the subset of breast cancers that are negative for estrogen receptor (ER), progesterone receptor, and HER2. While the selective ER modulator tamoxifen or anti-HER2 therapy for breast cancer patients with ER positive or HER2 protein overexpression are the most successful examples of targeted therapies, only limited therapies are available for patients with TNBCs, which are associated with a poor prognosis. Advance in next-generation sequencing enables us to identify actionable driver mutations that can be potentially treated by targeted therapies in each cancer patient. The aim of this study is to examine actionable driver mutations in TNBCs in Japan by comprehensive genomic sequencing (CGS) with 435 gene panel, and compare the driver events in Japan with TCGA database to validate the utility of CGS. Methods: We examined all exons of 435 known cancer genes in Japanese TNBC patients (N = 53) by CGS and evaluated for concordance among independent data obtained from The Cancer Genome Atlas-TNBC whole exome sequencing database (N = 123). Results: Oncogenic driver mutations were identified in 51 of 53 Japanese patients (96%) with TNBC and 36 of 53 patients (67%) harbored mutations in genes associated with FDA-approved targeted therapies, indicating the potential clinical utility of a large gene panel for evaluating patients with TNBC. Among 80 total genetic alterations, frequently mutated genes ( &gt; 10% patients) were TP53, PIK3CA and PTEN. Overall, the mutation spectrum of the Japanese patients is similar to that of the TCGA population, except amplification of MYC. Conclusions: Use of a CGS panel of 435 genes can reliably identify all of the critical mutations in TNBC patients, which are similar as TCGA data. The information derived from CGS can be used to determine the optimal treatment for TNBC patients.

The cholesterol metabolite 27-hydroxycholesterol stimulates cell proliferation via ER\u03b2 in prostate cancer cells

BackgroundFor every six men, one will be diagnosed with prostate cancer (PCa) in their lifetime. Estrogen receptors (ERs) are known to play a role in prostate carcinogenesis. However, it is unclear whether the estrogenic effects are mediated by estrogen receptor α (ERα) or estrogen receptor β (ERβ). Although it is speculated that ERα is associated with harmful effects on PCa, the role of ERβ in PCa is still ill-defined. The cholesterol oxidized metabolite 27-hydroxycholesterol (27-OHC) has been found to bind to ERs and act as a selective ER modulator (SERM). Increased 27-OHC levels are found in individuals with hypercholesterolemia, a condition that is suggested to be a risk factor for PCa.MethodsIn the present study, we determined the extent to which 27-OHC causes deleterious effects in the non-tumorigenic RWPE-1, the low tumorigenic LNCaP, and the highly tumorigenic PC3 prostate cancer cells. We conducted cell metabolic activity and proliferation assays using MTS and CyQUANT dyes, protein expression analyses via immunoblots and gene expression analyses via RT-PCR. Additionally, immunocytochemistry and invasion assays were performed to analyze intracellular protein distribution and quantify transepithelial cell motility.ResultsWe found that incubation of LNCaP and PC3 cells with 27-OHC significantly increased cell proliferation. We also demonstrate that the ER inhibitor ICI 182,780 (fulvestrant) significantly reduced 27-OH-induced cell proliferation, indicating the involvement of ERs in proliferation. Interestingly, ERβ levels, and to a lesser extent ERα, were significantly increased following incubation of PCa cells with 27-OHC. Furthermore, in the presence of the ERβ specific inhibitor, PHTPP, 27-OHC-induced proliferation is attenuated.ConclusionsAltogether, our results show for the first time that 27-OHC, through ER activation, triggers deleterious effect in prostate cancer cell lines. We propose that dysregulated levels of 27-OHC may trigger or exacerbate prostate cancer via acting on ERβ.

Potential role of antiestrogens in treating ovarian cancer

Ovarian cancer is the deadliest of all gynecologic malignancies and remains the fifth leading cause of cancer related deaths among women (1). High-grade serous ovarian cancer (HGSOC) is the most predominant and lethal subtype accounting for about 70% of ovarian cancer cases (2). The standard of care involves platinum and taxol based cytotoxic chemotherapy which has remained unchanged for the past 3 decades (3,4). Development of individualized targeted therapies catering to the specific tumor characteristics is needed. Andersen and colleagues report the presence of a subset of estrogen dependent HGSOC and have identified estrogen responsive features, which can be used to determine patient cohorts who can benefit from endocrine therapy. Endocrine based therapies have been found to be effective when targeting estrogen receptor (ER) in ER positive metastatic breast cancer (5). Inhibition of ER is considered as an alternative in recurrent ovarian cancer patients who are resistant to the carbo-taxol based standard chemotherapy (6). However, changes in expression of ER have been reported between matched primary and recurrent ovarian cancer (7). Therefore, it is essential to take this into account while planning therapies involving ER inhibition. In their article Andersen and colleagues suggest that many OC patients exhibit high expression of ERα and have identified an ER dependent gene expression signature (8). They further report that the selective ER-alpha down-regulator (SERD) fulvestrant is more effective than the selective ER modulator (SERM) 4-Hydroxytamoxifen (4OHT) in inhibiting the growth of ERα expressing ovarian cancer.

Estrogens regulate life and death in mitochondria.

Estrogens coordinate and integrate cellular metabolism and mitochondrial activities by direct and indirect mechanisms mediated by differential expression and localization of estrogen receptors (ER) in a cell-specific manner. Estrogens regulate transcription and cell signaling pathways that converge to stimulate mitochondrial function- including mitochondrial bioenergetics, mitochondrial fusion and fission, calcium homeostasis, and antioxidant defense against free radicals. Estrogens regulate nuclear gene transcription by binding and activating the classical genomic estrogen receptors α and β (ERα and ERβ) and by activating plasma membrane-associated mERα, mERβ, and G-protein coupled ER (GPER, GPER1). Localization of ERα and ERβ within mitochondria and in the mitochondrial membrane provides additional mechanisms of regulation. Here we review the mechanisms of rapid and longer-term effects of estrogens and selective ER modulators (SERMs, e.g., tamoxifen (TAM)) on mitochondrial biogenesis, morphology, and function including regulation of Nuclear Respiratory Factor-1 (NRF-1, NRF1) transcription. NRF-1 is a nuclear transcription factor that promotes transcription of mitochondrial transcription factor TFAM (mtDNA maintenance factorFA) which then regulates mtDNA-encoded genes. The nuclear effects of estrogens on gene expression directly controlling mitochondrial biogenesis, oxygen consumption, mtDNA transcription, and apoptosis are reviewed.