Structure-based pharmacophore modeling for precision inhibition of mutant ESR2 in breast cancer: A systematic computational approach.

BACKGROUND: Breast cancer, a leading cause of female mortality, is closely linked to mutations in estrogen receptor beta (ESR2), particularly in the ligand-binding domain, which contributed to altered signaling pathways and uncontrolled cell growth. OBJECTIVES/AIMS: This study investigates the molecular and structural aspects of ESR2 mutant proteins to identify shared pharmacophoric regions of ESR2 mutant proteins and potential therapeutic targets aligned within the pharmacophore model. METHODS: This study was initiated by establishing a common pharmacophore model among three mutant ESR2 proteins (PDB ID: 2FSZ, 7XVZ, and 7XWR). The generated shared feature pharmacophore (SFP) includes four primary binding interactions: Hydrogen bond donors (HBD), hydrogen bond acceptors (HBA), hydrophobic interactions (HPho), and Aromatic interactions (Ar), along with halogen bond donors (XBD) and totalling 11 features (HBD: 2, HBA: 3, HPho: 3, Ar: 2, XBD: 1). By employing an in-house Python script, these 11 features distributed into 336 combinations, which were used as query to isolate a drug library of 41,248 compounds and subjected to virtual screening through the generated SFP. RESULTS: The virtual screening demonstrated 33 hits showing potential pharmacophoric fit scores and low RMSD value. The top four compounds: ZINC94272748, ZINC79046938, ZINC05925939, and ZINC59928516 showed a fit score of more than 86% and satisfied the Lipinski rule of five. These four compounds and a control underwent molecular (XP Glide mode) docking analysis against wild-type ESR2 protein (PDB ID: 1QKM), resulting in binding affinity of -8.26, -5.73, -10.80, and -8.42 kcal/mol, respectively, along with the control -7.2 kcal/mol. Furthermore, the stability of the selected candidates was determined through molecular dynamics (MD) simulations of 200 ns and MM-GBSA analysis. CONCLUSION: Based on MD simulations and MM-GBSA analysis, our study identified ZINC05925939 as a promising ESR2 inhibitor among the top four hits. However, it is essential to conduct further wet lab evaluation to assess its efficacy.

Segregation of nuclear and membrane-initiated actions of estrogen receptor using genetically modified animals and pharmacological tools.

Estrogen receptor alpha (ERα) and beta (ERß) are members of the nuclear receptor superfamily, playing widespread functions in reproductive and non-reproductive tissues. Beside the canonical function of ERs as nuclear receptors, in this review, we summarize our current understanding of extra-nuclear, membrane-initiated functions of ERs with a specific focus on ERα. Over the last decade, in vivo evidence has accumulated to demonstrate the physiological relevance of this ERα membrane-initiated-signaling from mouse models to selective pharmacological tools. Finally, we discuss the perspectives and future challenges opened by the integration of extra-nuclear ERα signaling in physiology and pathology of estrogens.

Bisphenol A derivatives act as novel coactivator-binding inhibitors for estrogen receptor ß.

Bisphenol A and its derivatives are recognized as endocrine disruptors based on their complex effects on estrogen receptor (ER) signaling. While the effects of bisphenol derivatives on ERα have been thoroughly evaluated, how these chemicals affect ERß signaling is less well understood. Herein, we sought to identify novel ERß ligands using a radioligand competitive binding assay to screen a chemical library of bisphenol derivatives. Many of the compounds identified showed intriguing dual activities as both ERα agonists and ERß antagonists. Docking simulations of these compounds and ERß suggested that they bound not only to the canonical binding site of ERß but also to the coactivator binding site located on the surface of the receptor, suggesting that they act as coactivator-binding inhibitors (CBIs). Receptor-ligand binding experiments using WT and mutated ERß support the presence of a second ligand-interaction position at the coactivator-binding site in ERß, and direct binding experiments of ERß and a coactivator peptide confirmed that these compounds act as CBIs. Our study is the first to propose that bisphenol derivatives act as CBIs, presenting critical insight for the future development of ER signaling-based drugs and their potential to function as endocrine disruptors.

Protein druggability assessment for natural products using in silico simulation: A case study with estrogen receptor and the flavonoid genistein.

Traditional herbal medicine (THM) comprises a vast number of natural compounds. Most of them are metabolized into different structures after administration, which makes the clarification of THM's mode of action more complicated. To evaluate the biological activities of those components and metabolites, in silico simulation technology is helpful. We focused on mixed-solvent molecular dynamics (MD) simulation for druggability assessment of natural products. Mixed-solvent MD is an in silico simulation method for the exploration of ligand-binding sites on target proteins, which uses water and an organic molecule mixture. The selection of organic small molecules is an important factor for predicting the characteristics of natural products. In this study, we used the known crystal structure of estrogen receptors with genistein as a test case and explored fragments reflecting the characteristics of natural products. We found that structures with a 4-pyrone structure are more often included in the natural products database compared with the DrugBank database, and we selectively detected the known-binding sites of estrogen receptor α and ß. The results indicate that the 4-pyrone structure might be promising for predicting the protein druggability of flavonoids. Additionally, mixed-solvent MD simulation discriminates the selectivity of genistein between estrogen receptor ß and α, indicating that the simulation can be evaluated using indices that differ from those of traditional ligand docking. Although this approach is still in its early stages, it has the potential to provide valuable information for understanding the diverse biological activities of natural products.

Experimental and molecular docking studies of estrogen-like and anti-osteoporosis activity of compounds in Fructus Psoraleae.

ETHNOPHARMACOLOGICAL RELEVANCE: Fructus Psoraleae (FP), dry mature fruits of Cullen corylifolium (L.) Medik., has been used clinically to treat kidney yang deficiency-induced impotence, asthma and cold pain in waist and knee caused by kidney deficiency. A study of the source of the significant kidney-enhancing effect of FP revealed that it may be due to its strong estrogen-like activity. AIM OF THE STUDY: This study aimed to investigate the estrogen-like activity of the FP extract and 13 bioactive compounds in it, as well as the mechanisms underlying their estrogen-like and anti-osteoporosis activities. MATERIALS AND METHODS: The estrogen-like activities of the 75% ethanol-only FP extract, and 75% ethanol plus petroleum ether, ethyl acetate, n-butanol or water FP extracts were each measured using Cell Counting Kit-8 (CCK-8) and luciferase reporter gene assays. The compounds were identified by high-performance liquid chromatography analysis. The activation of estrogen receptor signaling by the compounds was compared with that by estradiol (E2) using the molecular docking software MOE-Dock 2008.10. The activation of the ER-Wnt-ß-catenin signaling pathway was investigated using an alkaline phosphatase (ALP) assay, qPCR analysis and Western blot analysis. RESULTS: The results revealed that the 75% ethanol plus ethyl acetate extract showed the highest estrogen-like activity among the four 75% ethanol extract fractions (further extracted with petroleum ether, ethyl acetate, n-butanol or water). Some compounds in FP showed strong estrogenic effect and anti-osteoporosis activity, and activated the Wnt-ß-catenin pathway. The isoflavone compound was the most active. CONCLUSIONS: This study demonstrated that FP has a strong estrogen-like activity and some of its component compounds have anti-osteoporosis activity by activating the ER-Wnt-ß-catenin signaling pathway. Our detections provide a new insight into the mechanisms underlying the estrogen-like and anti-osteoporosis activities of FP, as well as a better understanding of structure effects.

Dietary isoflavone-induced, estrogen receptor-ß-mediated proliferation of Caco-2 cells is modulated by gallic acid.

Dietary isoflavones and their biotransformation products (from food fermentation) are estrogen mimics which activate estrogen receptors (ER)α and ERß. In silico molecular modelling is used to determine theoretical binding energies of genistein, daidzein and hydroxylated biotransformation products, and to investigate structure-binding energy relationships with ERß. Results suggest that ligand hydroxyl arrangement determines binding energy and influences binding affinity. Caco-2 cells (ERß expressing) are used to study the proliferative effect of genistein, daidzein and their hydroxylated biotransformation products. Isoflavones/biotransformation products showed weaker enhancement of Caco-2 proliferation than 17ß-estradiol. The EC50s of isoflavones/biotransformation products agreed with in silico-predicted binding affinity order. Hydroxylated biotransformation products studied showed greater Caco-2 proliferative effects than the parent isoflavones except 8-hydroxygenistein, probably due to unfavourable ERß interactions caused by 8-hydroxygenistein's extra hydroxyl. Caco-2 pre-treatment with UDP-glucose dehydrogenase inhibitor gallic acid promoted genistein/8-hydroxygenistein-mediated proliferation. This is probably due to a reduced isoflavone glucuronidation to form low estrogenicity glucuronides. Findings are discussed in the context of dietary isoflavones/gallic acid and effects on proliferation of ERß-expressing gut cancer cells.

SAR Study on Estrogen Receptor α/ß Activity of (Iso)flavonoids: Importance of Prenylation, C-Ring (Un)Saturation, and Hydroxyl Substituents.

Many botanicals used for women's health contain estrogenic (iso)flavonoids. The literature suggests that estrogen receptor beta (ERß) activity can counterbalance estrogen receptor alpha (ERα)-mediated proliferation, thus providing a better safety profile. A structure-activity relationship study of (iso)flavonoids was conducted to identify ERß-preferential structures, overall estrogenic activity, and ER subtype estrogenic activity of botanicals containing these (iso)flavonoids. Results showed that flavonoids with prenylation on C8 position increased estrogenic activity. C8-prenylated flavonoids with C2-C3 unsaturation resulted in increased ERß potency and selectivity [e.g., 8-prenylapigenin (8-PA), EC50 (ERß): 0.0035 ± 0.00040 µM], whereas 4'-methoxy or C3 hydroxy groups reduced activity [e.g., icaritin, EC50 (ERß): 1.7 ± 0.70 µM]. However, nonprenylated and C2-C3 unsaturated isoflavonoids showed increased ERß estrogenic activity [e.g., genistein, EC50 (ERß): 0.0022 ± 0.0004 µM]. Licorice (Glycyrrhiza inflata, [EC50 (ERα): 1.1 ± 0.20; (ERß): 0.60 ± 0.20 µg/mL], containing 8-PA, and red clover [EC50 (ERα): 1.8 ± 0.20; (ERß): 0.45 ± 0.10 µg/mL], with genistein, showed ERß-preferential activity as opposed to hops [EC50 (ERα): 0.030 ± 0.010; (ERß): 0.50 ± 0.050 µg/mL] and Epimedium sagittatum [EC50 (ERα): 3.2 ± 0.20; (ERß): 2.5 ± 0.090 µg/mL], containing 8-prenylnaringenin and icaritin, respectively. Botanicals with ERß-preferential flavonoids could plausibly contribute to ERß-protective benefits in menopausal women.

Indole Derivative Interacts with Estrogen Receptor Beta and Inhibits Human Ovarian Cancer Cell Growth.

Ovarian cancer remains the leading cause of mortality among gynecological tumors. Estrogen receptor beta (ERß) expression has been suggested to act as a tumor suppressor in epithelial ovarian cancer by reducing both tumor growth and metastasis. ERß expression abnormalities represent a critical step in the development and progression of ovarian cancer: for these reasons, its re-expression by genetic engineering, as well as the use of targeted ERß therapies, still constitute an important therapeutic approach. 3-{[2-chloro-1-(4-chlorobenzyl)-5-methoxy-6-methyl-1H-indol-3-yl]methylene}-5-hydroxy-6-methyl-1,3-dihydro-2H-indol-2-one, referred to here as compound 3, has been shown to have cytostatic as well cytotoxic effects on various hormone-dependent cancer cell lines. However, the mechanism of its anti-carcinogenic activity is not well understood. Here, we offer a possible explanation of such an effect in the human ovarian cancer cell line IGROV1. Chromatin binding protein assay and liquid chromatography mass spectrometry were exploited to localize and quantify compound 3 in cells. Molecular docking was used to prove compound 3 binding to ERß. Mass spectrometry-based approaches were used to analyze histone post-translational modifications. Finally, gene expression analyses revealed a set of genes regulated by the ERß/3 complex, namely CCND1, MYC, CDKN2A, and ESR2, providing possible molecular mechanisms that underline the observed antiproliferative effects.

Molecular docking simulation and in vitro studies on estrogenic activities of flavonoids from leaves of Carya cathayensis Sarg.

The main purpose of this study was to evaluate the estrogenic properties of total flavonoids (TFs) and five flavonoid monomers (cardamonin (Car), pinostrobin chalcone (PC), wogonin (Wo), chrysin (Chr) and Pinocembrin (PI)) from leaves of Carya cathayensis Sarg (LCC). TFs from LCC were isolated and determined using HPLC. The 3-[4,5-dimethylthiazole-2-yl]-2,5-diphenyltetrazolium bromide (MTT) assay and flow cytometry were performed to assess the effects of flavonoids on cell proliferation and cell cycle, respectively. The molecular docking technique was applied to investigate binding conformations of the monomers from LCC to the estrogen receptor ERα and ERß. Gene and protein expression patterns were assessed using quantitative real-time PCR (qRT-PCR) and western blot, respectively. The results showed that TFs, Car, PC, Wo and Chr promoted proliferation of MCF-7 cells and cell transition from the G1 to S phase, and inhabitation of MCF-7 cell proliferation was observed after the treatment of PI. Molecular docking studies confirmed ERs as molecular targets for the monomers. TFs, Car, PC, Wo and Chr from LCC promoted gene expression of ERα, ERß, progesterone receptor (PR) and pS2. Our collective results demonstrated that TFs and monomers from LCC may exert ER agonist activity through competitively bind to ER, inducing ER upregulation and active ER to estrogen response element (ERE)- independent gene regulation. As an abundant natural product, LCC may provide a novel medicinal source for treatment of diseases caused by estrogen deficiency.

Selective regulation of RANKL/RANK/OPG pathway by heparan sulfate through the binding with estrogen receptor ß in MC3T3-E1 cells.

Heparan sulfate (HS) is a linear anionic polysaccharide with repeating sulfated disaccharide units, which has been proven with various regulatory osteogenesis effects through multi-pathway signaling, but its impacts on receptor-activator of nuclear factor kappa beta ligand/receptor-activator of nuclear factor kappa beta/osteoprotegerin (RANKL/RANK/OPG) pathway is still poorly understood. In this study, the binding affinity between HS and estrogen receptor beta (ER-ß) was virtually analyzed using computer simulative docking method and experimentally studied by surface plasmon resonance (SPR). Thereafter, short interfering RNAs (siRNAs) were constructed to deliberately down-regulate the level of ER-ß in MC3T3-E1 cell line, and the transfected and non-transfected osteoblasts displaying good growth conditions were subsequently treated with HS. The results indicated that HS significantly reduced the expression level of RANKL without markedly affecting the expression of decoy receptor OPG during osteoblast differentiation, which can be partially owing to the interaction between HS and ER-ß. Meanwhile, the expression of RANKL in MC3T3-E1 cells was obviously increased after the transfection, demonstrating ER-ß as the key biomarker that regulates RANKL expression. The current work provided important supplementary information on the regulation mechanism of RANKL/RANK/OPG axis by HS.

Induced osteoblast differentiation by amide derivatives of stilbene: The possible osteogenic agents.

A series of amide derivatives of stilbene was synthesized and investigated for osteogenic activity. Out of sixteen, seven compounds viz19c, 19g, 19i, 24b, 25a, 25c and 26a showed significant osteoblast differentiation within 1 pM-1 µM concentrations. Amongst all, 26a was identified as most active molecule which presented effective mineralization of osteoblasts and expression of mRNA of osteogenic marker gene such as BMP-2, ALP, and Runx-2 at 1 pM. In estrogen-deficient balb/c mice, 26a showed significant osteogenic activity at 5 mg-kg-1 body weight dose. The protein expression study for estrogen receptors α and ß (ER-α & ER-ß) using mouse calvarial osteoblasts (MCOs) and molecular docking analyses showed preferential expression of ER-ß by 26a indicating the possibility of ER-ß mediated osteogenic activity of 26a.

Interaction of Coumarin Phytoestrogens with ERα and ERß: A Molecular Dynamics Simulation Study.

Coumarin phytoestrogens, as one of the important classes of phytoestrogens, have been proved to play an important role in various fields of human life. In this study, molecular simulation method including molecular docking and molecular dynamics methods were performed to explore the various effects between four classical coumarin phytoestrogens (coumestrol, 4-methoxycoumestrol, psoralen and isopsoralen), and estrogen receptors (ERα, ERß), respectively. The calculated results not only proved that the four coumarin phytoestrogens have weaker affinity than 17ß-estradiol to both ERα, and ERß, but also pointed out that the selective affinity for ERß is greater than ERα. In addition, the binding mode indicated that the formation of hydrogen bond and hydrophobic interaction have an important effect on the stability of the complexes. Further, the calculation and decomposition of binding free energy explored the main contribution interactions to the total free energy.

LARMD: integration of bioinformatic resources to profile ligand-driven protein dynamics with a case on the activation of estrogen receptor.

Protein dynamics is central to all biological processes, including signal transduction, cellular regulation and biological catalysis. Among them, in-depth exploration of ligand-driven protein dynamics contributes to an optimal understanding of protein function, which is particularly relevant to drug discovery. Hence, a wide range of computational tools have been designed to investigate the important dynamic information in proteins. However, performing and analyzing protein dynamics is still challenging due to the complicated operation steps, giving rise to great difficulty, especially for nonexperts. Moreover, there is a lack of web protocol to provide online facility to investigate and visualize ligand-driven protein dynamics. To this end, in this study, we integrated several bioinformatic tools to develop a protocol, named Ligand and Receptor Molecular Dynamics (LARMD, http://chemyang.ccnu.edu.cn/ccb/server/LARMD/ and http://agroda.gzu.edu.cn:9999/ccb/server/LARMD/), for profiling ligand-driven protein dynamics. To be specific, estrogen receptor (ER) was used as a case to reveal ERß-selective mechanism, which plays a vital role in the treatment of inflammatory diseases and many types of cancers in clinical practice. Two different residues (Ile373/Met421 and Met336/Leu384) in the pocket of ERß/ERα were the significant determinants for selectivity, especially Met336 of ERß. The helix H8, helix H11 and H7-H8 loop influenced the migration of selective agonist (WAY-244). These computational results were consistent with the experimental results. Therefore, LARMD provides a user-friendly online protocol to study the dynamic property of protein and to design new ligand or site-directed mutagenesis.

Total Polysaccharides of Lily Bulb Ameliorate Menopause-Like Behavior in Ovariectomized Mice: Multiple Mechanisms Distinct from Estrogen Therapy.

Our previous study has demonstrated the effects of aqueous extract of lily bulb in alleviating menopause-related psychiatric symptoms in ovariectomized (OVX) mice. This study sought to further investigate the psychotropic effects of total polysaccharides of lily bulb (TPLB) against anxiety, depression, and cognitive deterioration and the underlying mechanisms in OVX mice using behavioral, neurochemical, molecular, and proteomic approaches in comparison with estrogen therapy. While TPLB and estradiol showed similar effects in reducing OVX-induced anxiety, depression, and cognitive impairment, the psychotropic effects of TPLB were more closely associated with the predominant activation of estrogen receptors (ERs) and regulation of brain regional neurotransmitters and neurotrophins with minor effects on the uterus. Estradiol had similar potencies in binding affinity at ERα and ERß, which caused widespread genetic and epigenetic effects. In contrast, TPLB displayed a higher affinity at ERß than ERα, triggering the specific Ras/Akt/ERK/CREB signaling pathway without affecting any epigenetic activity. TPLB additionally modulated multiple proteins associated with mitochondrial oxidative stress, but estradiol did not. These results indicate that TPLB has comparable efficacy in reducing menopause-associated neuropsychological symptoms with a better safety profile compared to estrogen therapy. We suggest that TPLB could serve as a novel agent for menopause syndrome.

ER subtype selectivity of m-carborane-containing phenols: C-alkyl groups on the m-carborane cage enhance ERα selectivity.

Estrogen receptor (ER) exhibits two subtypes, ERα and ERß, whose biological functions are quite different despite expression in the same tissues. We developed diiodo-m-carborane derivative 3a, which showed 14-fold selectivity for ERß with high binding affinity toward ERß. Interestingly, introduction of an alkyl group into the carbon atom of the m-carborane cage of 3a markedly enhanced the binding affinity toward ERα and decreased affinity toward ERß. C-n-propyl derivative 3d showed 28-fold selectivity for ERα in an ER binding assay and promoted proliferation of MCF-7 breast cancer cells. Docking simulation studies suggest that the directions of the n-propyl group and the diiodo substituent introduced on the m-carborane cage play important roles for the control of ER subtype selectivity. As 3a and 3d showed ERß and ERα selectivity with high binding affinity, respectively, these ligands may be useful as biological tools to aid in understanding the different roles of ER subtypes.

Synthesis and characterization of hydrogen peroxide activated estrogen receptor beta ligands.

The development and evaluation of selective estrogen receptor modulators (SERMs) is of interest because of the complex and significant role of estrogen receptors in normal tissues as well as disease states. In neurodegenerative disorders such as Alzheimer's disease and multiple sclerosis, estrogen receptor beta (ERß) seems to provide a protective anti-inflammatory response. Due to the increase in reactive oxygen species (ROS) in these diseases, we have masked ERß ligands, including diarylpropionitrile (DPN), as boronate esters that release the active estrogen in the presence of H2O2. Here we demonstrate their synthesis, decreased binding affinities, kinetics of release, and selectivity toward ROS. The most promising ligand can be unmasked in the presence of pathological H2O2 to modulate ERß transcription in cells.

Estrogen receptor beta increases sensitivity to enzalutamide in androgen receptor-positive triple-negative breast cancer.

PURPOSE: Androgen receptor (AR) is playing an important role in the progression of a subset of TNBC. We evaluated the impact of ERß expression along with anti-AR drugs in AR-positive TNBC. METHODS: ERß expression was examined in AR-positive TNBC cell line using MTT assay, scratch and Annexin V-FITC assay in the presence or absence of anti-androgens. Protein levels of involved molecules were assessed using Western blot. Receptors' localization was detected by immunofluorescence and their physical association was examined using proximity ligation assay (PLA), which enables the visualization of interacting proteins in fixed cells and tissues. RESULTS: Transient transfection of ERß in MDA-MB 453 AR-positive TNBC cell line significantly inhibited cell proliferation, metastatic potential and induced apoptosis. ERß expression reversed the aggravating role of AR in both indirect and direct ways. Indirectly, ERß decreased AR activation through the inhibition of PI3K/AKT signaling pathway. Directly, ERß formed heterodimers with AR in MDA-MB 453 cells and in human tissue samples impeding AR from forming homodimers. Enzalutamide is a more potent anti-androgen in AR + TNBC compared to bicalutamide. ERß expression increased the sensitivity of MDA-MB 453 cells to anti-androgens and especially to enzalutamide. The administration of enzalutamide enhanced AR:ERß heterodimers formation increasing the anti-tumor capacity of ERß. CONCLUSIONS: Collectively, our results provide evidence for a novel mechanism by which ERß exerts oncosuppressive effect in AR-positive TBNC through direct and indirect interactions with AR. Moreover, ERß expression may identify a new subset of TNBC that would respond more favorable to anti-androgens.

Zerumbone binding to estrogen receptors: an in-silico investigation.

Breast cancer is the most frequent malignancy among females worldwide. Estrogen receptor (ER) mediate important pathophysiological signaling pathways induced by estrogens, and is regarded as a promising target for the treatment of breast cancer. Zerumbone (2,6,9,9-tetramethylcycloundeca-2,6,10-trien-1-one; ZER), a chemical constituent present in the Zingiber zerumbet is known to exhibit anti-breast cancer activity by modulating several proteins to induce apoptosis. Medicinal chemists usually exploit lead compounds of natural origin to develop molecules with improved pharmacological properties. Current study is intended to utilize molecular modeling techniques to investigate the interaction of ZER with estrogen receptors. AutoDock was used to predict the binding modes of ZER and target receptors. Stability of the ZER-ER complex was verified by molecular dynamics simulation using Desmond software. Docked ZER was further optimized by density functional theory (DFT) using Gaussian09 program. Analysis of docked conformations in terms of binding energy disclosed estrogen receptor-ß (ERß) as more promising than estrogen receptor-α (ERα). Evaluation of MD trajectories of ZER bound to both ERα and ERß showed appreciable stability with minimum Cα-atom root mean square deviation shifts. DFT based global reactivity descriptors such as electron affinity, hardness, chemical potential, electronegativity and electrophilicity index, calculated from the energies of highest occupied and lowest unoccupied molecular orbitals underscored the electronic features governing viability of the ZER for interaction with the target receptors. In conclusion, these findings can be exploited to design and develop novel anticancer agents based on the lead compound, ZER.

A-C Estrogens as Potent and Selective Estrogen Receptor-Beta Agonists (SERBAs) to Enhance Memory Consolidation under Low-Estrogen Conditions.

Estrogen receptor-beta (ERß) is a drug target for memory consolidation in postmenopausal women. Herein is reported a series of potent and selective ERß agonists (SERBAs) with in vivo efficacy that are A-C estrogens, lacking the B and D estrogen rings. The most potent and selective A-C estrogen is selective for activating ER relative to seven other nuclear hormone receptors, with a surprising 750-fold selectivity for the ß over α isoform and with EC50s of 20-30 nM in cell-based and direct binding assays. Comparison of potency in different assays suggests that the ER isoform selectivity is related to the compound's ability to drive the productive conformational change needed to activate transcription. The compound also shows in vivo efficacy after microinfusion into the dorsal hippocampus and after intraperitoneal injection (0.5 mg/kg) or oral gavage (0.5 mg/kg). This simple yet novel A-C estrogen is selective, brain penetrant, and facilitates memory consolidation.

A high-affinity subtype-selective fluorescent probe for estrogen receptor ß imaging in living cells.

Estrogen receptor ß (ERß) has recently been identified as a pharmaceutical target in hormone replacement therapy for breast cancers. However, the biological function of ERß in disease progression remains unclear. A highly ERß-selective fluorescent probe (FPNM) was discovered exhibiting nanomolar affinity for ERß with an ERß/ERα selectivity as high as 80, which allowed specific labeling of intracellular ERß. Moreover, distinct ERß dynamics in various cellular bio-settings such as prostate cancer (DU-145) or triple-negative breast cancer (MDA-MB-231) cells were directly observed for the first time viaFPNM staining.