Estrogen receptor beta expression and role in cancers

Estrogen drives the growth of some cancers, such as breast cancer, via estrogen receptor alpha (ERβ). Estrogen also activates ERβ, but whether ERβ is expressed and has a role in different cancers is debated. The use of nonspecific antibodies has contributed to the confusion, and this review delves into ERβ's controversial role in cancer and focuses on tumor expression that can be supported by non-antibody-dependent assays. We discuss its expression at the transcript level and focus on its potential role in lymphoma, granulosa cell tumor, testicular, and adrenal cancers, emphasizing recent findings and the complexities that necessitate further research.

25-hydroxycholesterol promotes proliferation and metastasis of lung adenocarcinoma cells by regulating ERβ/TNFRSF17 axis

Lung adenocarcinoma is the main type of lung cancer in women. Our previous findings have evidenced that 25-hydroxycholesterol (25-HC) promotes migration and invasion of lung adenocarcinoma cells (LAC), during which LXR as a 25-HC receptor plays an important role. Estrogen receptor beta (ERβ) is a receptor of 27-hydroxycholesterol that is structurally analogous to 25-HC, but its role in the functional actions of 25-HC remained largely unknown. In this study, we demonstrated that 25-HC treatment triggered ERβ expression in LAC. Knockdown of ERβ inhibited 25-HC-mediated proliferation, migration and invasion, and reduced 25-HC-induced LAC metastasis in vivo. Further investigation revealed that ERβ knockdown restrained the expression of TNFRSF17 (BCMA). In vivo experiments also confirmed that ERβ knockdown blocked 25-HC-induced TNFRSF17 expression. TNFRSF17 knockdown also restrained 25-HC-induced proliferation, migration and invasion. Bioinformatic analysis showed that the levels of ERβ and TNFRSF17 were elevated in lung adenocarcinoma, and were closely related to tumor stages and nodal metastasis status. These results suggested that 25-HC promoted the proliferation and metastasis of LAC by regulating ERβ/TNFRSF17 axis.

Benzo[a]pyrene exposure affects colorectal cancer susceptibility by regulating ERβ-mediated LINC02977 transcription

Environmental pollutants known as polycyclic aromatic hydrocarbons (PAHs) are produced through the incomplete combustion of organic material. While PAHs have been investigated as genotoxicants, they can also operate through nongenotoxic pathways in estrogen-dependent malignancies, such as breast, cervical and ovarian cancer. However, whether PAHs induce colorectal cancer (CRC) risk through estrogenic effects is still illusive. Here, we systematically investigated the abnormal expression and activation of estrogen receptor beta (ERβ) regulated by PAHs in CRC as well as the underlying mechanisms of ERβ-mediated CRC risk. Based on the 300 plasma samples from CRC patients and healthy controls detected by GC-MS/MS, we found that the plasma concentrations of benzo[a]pyrene (BaP) were significantly higher in CRC cases than in healthy controls, with significant estrogenic effects. Moreover, histone deacetylase 2 (HDAC2)-induced deacetylation of the promoter decreases ERβ expression, which is associated with poor overall survival and advanced tumor stage. The study also revealed that BaP and estradiol (E2) had different carcinogenic effects, with BaP promoting cell proliferation and inhibiting apoptosis, while E2 had the opposite effects. Additionally, this study mapped ERβ genomic binding regions by performing ChIP-seq and ATAC-seq and identified genetic variants of rs1411680 and its high linkage disequilibrium SNP rs6477937, which were significantly associated with CRC risk through meta-analysis of two independent Chinese population genome-wide association studies comprising 2,248 cases and 3,173 controls and then validation in a large-scale European population. By integrating data from functional genomics, we validated the regulatory effect of rs6477937 as an ERβ binding-disrupting SNP that mediated allele-specific expression of LINC02977 in a long-range chromosomal interaction manner, which was found to be highly expressed in CRC tissues. Overall, this study suggests that the different active effects on ERβ by PAHs and endogenous E2 may play a crucial role in the development and progression of CRC and highlights the potential of targeting ERβ and its downstream targets for CRC prevention and treatment.

A novel ERβ high throughput microscopy platform for testing endocrine disrupting chemicals

In this study we present an inducible biosensor model for the Estrogen Receptor Beta (ERβ), GFP-ERβ:PRL-HeLa, a single-cell-based high throughput (HT) in vitro assay that allows direct visualization and measurement of GFP-tagged ERβ binding to ER-specific DNA response elements (EREs), ERβ-induced chromatin remodeling, and monitor transcriptional alterations via mRNA fluorescence in situ hybridization for a prolactin (PRL)-dsRED2 reporter gene. The model was used to accurately (Z' = 0.58-0.8) differentiate ERβ-selective ligands from ERα ligands when treated with a panel of selective agonists and antagonists. Next, we tested an Environmental Protection Agency (EPA)-provided set of 45 estrogenic reference chemicals with known ERα in vivo activity and identified several that activated ERβ as well, with varying sensitivity, including a subset that is completely novel. We then used an orthogonal ERE-containing transgenic zebrafish (ZF) model to cross validate ERβ and ERα selective activities at the organism level. Using this environmentally relevant ZF assay, some compounds were confirmed to have ERβ activity, validating the GFP-ERβ:PRL-HeLa assay as a screening tool for potential ERβ active endocrine disruptors (EDCs). These data demonstrate the value of sensitive multiplex mechanistic data gathered by the GFP-ERβ:PRL-HeLa assay coupled with an orthogonal zebrafish model to rapidly identify environmentally relevant ERβ EDCs and improve upon currently available screening tools for this understudied nuclear receptor.

Estrogen receptor β affects hypoxia response in colorectal cancer cells

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

Erectile function and androgen and estrogen beta receptor gene polymorphisms in acromegalic men

PURPOSE

Sexual dysfunctions are often experienced by male patients with acromegaly, due to a combination of hypogonadism and other comorbidities, but are a scarcely investigated complication. Erectile dysfunction is also closely related to cardiovascular diseases through endothelial dysfunction. Therefore, this project aimed to assess the prevalence of erectile dysfunction in a population of acromegalic men and evaluate its association with cardio-metabolic disorders, also exploring associations with androgen and estrogen receptor gene polymorphisms.

METHODS

Sexually active men aged 18-65 with previous diagnosis of acromegaly were recruited. Clinical and laboratory data were retrospectively collected. Each patient also provided a blood sample for AR and ERβ gene polymorphisms analyses and filled out the IIEF-15 questionnaire.

RESULTS

Twenty men with previous diagnosis of acromegaly (mean age 48.4 ± 10.0 years) were recruited. 13/20 subjects (65%) had erectile dysfunction, but only four had a concurrent biochemical hypogonadism, with no significant correlation with IIEF-15 scores. Total testosterone negatively correlated with sexual intercourse satisfaction domain (ρ = - 0.595; p = 0.019) and general satisfaction domain (ρ = - 0.651; p = 0.009). IGF-1 levels negatively correlated with biochemical hypogonadism (ρ = - 0.585; p = 0.028). The number of CAG and CA repeats in AR and ERβ receptors genes was not significantly associated with IIEF-15 scores or with GH/IGF-1 levels, but a negative correlation between CA repeats and the presence of cardiomyopathy (ρ = - 0.846; p = 0.002) was present.

CONCLUSIONS

Men with acromegaly have a high prevalence of erectile dysfunction, but it does not appear to be correlated with treatments, testosterone levels and AR/ER-beta signaling. Nonetheless, a shorter CA polymorphic trait (ERbeta) is associated with the presence of cardiomyopathy. If confirmed, these data may suggest an association between an incorrect hormonal balance and increased cardiovascular risk in acromegaly subjects.

The identification of cianidanol as a selective estrogen receptor beta agonist and evaluation of its neuroprotective effects on Parkinson's disease models

AIM

The present study aims to identify selective estrogen receptor beta (ERβ) agonists and to evaluate the neuroprotective mechanism in Parkinson's disease (PD) models.

MAIN METHODS

In-silico studies were carried out using Maestro and GROMACS. Neuroprotective activity and apoptosis were evaluated using cytotoxicity assay and flow cytometry respectively. Gene expression studies were carried out by reverse transcription polymerase chain reaction. Motor and cognitive functions were assessed by actophotometer, rotarod, catalepsy, and elevated plus maze. The neuronal population in the substantia nigra and striatum of rats was assessed by hematoxylin and eosin staining.

KEY FINDINGS

Cianidanol was identified as a selective ERβ agonist through virtual screening. The cianidanol-ERβ complex is stable during the 200 ns simulation and was able to retain the interactions with key amino acid residues. Cianidanol (25 μM) prevents neuronal toxicity and apoptosis induced by rotenone in differentiated SH-SY5Y cells. Additionally, cianidanol (25 μM) increases the expression of ERβ, cathepsin D, and Nrf2 transcripts. The neuroprotective effects of cianidanol (25 μM) were reversed in the presence of a selective ERβ antagonist. In this study, we found that selective activation of ERβ could decrease the transcription of α-synuclein gene. Additionally, cianidanol (10, 20, 30 mg/kg, oral) improves the motor and cognitive deficit in rats induced by rotenone.

SIGNIFICANCE

Cianidanol shows neuroprotective action in PD models and has the potential to serve as a novel therapeutic agent for the treatment of PD.

Correlation between androgen and estrogen receptor expression and clinicopathologic features in carcinoma urinary bladder

INTRODUCTION

The molecular mapping of cancers by the Cancer Genome Atlas Project has accelerated the quest for new therapeutic targets for urinary bladder cancer, including sex steroid receptors. Previous studies have demonstrated conflicting results on their relationship with bladder cancer, and there is sparse data on their expression in the Indian population. The aim of our study is to examine the expression of androgen receptors (AR) and estrogen receptors (ERα and ERβ) in patients with bladder cancer and their correlation with clinicopathologic features.

MATERIALS AND METHODS

In this retrospective cohort study, a total of 132 patients, who were surgically managed for urinary bladder mass by transurethral resection or radical cystectomy in our institute, with transitional cell carcinoma on histopathology and with at least two years of follow-up were included. Their demographic and treatment details were obtained, histopathology blocks were retrieved and immunohistochemical staining for androgen and estrogen receptors was performed. Then, the relationship between their expression and clinicopathologic features was studied.

RESULTS

A total of 3.79% of patients showed estrogen receptor alpha positivity, 51.52% estrogen receptor beta positivity and 63.64% androgen receptor positivity. No statistically significant correlation was found between age of patients (p = 0.75/0.52/0.87), tumour stage and grade (0.71/0.3/0.21), pathological variant (p = 1/0.58/0.38) and overall survival (p = 0.70/0.052/0.45 for NMIBC and p = 0.82/0.36/0.22) and estrogen receptor alpha, estrogen receptor beta and androgen receptor-positive status, respectively. Estrogen receptor beta positivity was significantly higher in patients with unifocal (p = 0.015) and small tumours (< 5 cm) (p = 0.03), and its expression was associated with better disease-free survival (DFS) (p = 0.046) in patients of non-muscle invasive bladder cancer (NMIBC).

CONCLUSION

Our study has the largest sample size conducted on Indian population with results differing from previous studies conducted on western population. Estrogen receptor beta expression was significantly associated with small unifocal tumours and better DFS. Estrogen receptor alpha and androgen receptor expression were not found to be associated with the clinicopathologic features of the study population.

Pharmacological inhibition of KDM1A/LSD1 enhances estrogen receptor beta-mediated tumor suppression in ovarian cancer

Ovarian cancer (OCa) is the most lethal gynecologic cancer. Emerging data indicates that estrogen receptor beta (ERβ) functions as a tumor suppressor in OCa. Lysine-specific histone demethylase 1A (KDM1A) is an epigenetic modifier that acts as a coregulator for steroid hormone receptors. However, it remain unknown if KDM1A interacts with ERβ and regulates its expression/functions in OCa. Analysis of TCGA data sets indicated KDM1A and ERβ expression showed an inverse relationship in OCa. Knockout (KO), knockdown (KD), or inhibition of KDM1A increased ERβ isoform 1 expression in established and patient-derived OCa cells. Further, KDM1A interacts with and functions as a corepressor of ERβ, and its inhibition enhances ERβ target gene expression via alterations of histone methylation marks at their promoters. Importantly, KDM1A-KO or -KD enhanced the efficacy of ERβ agonist LY500307, and the combination of KDM1A inhibitor (KDM1Ai) NCD38 with ERβ agonist synergistically reduced the cell viability, colony formation, and invasion of OCa cells. RNA-seq and DIA mass spectrometry analyses showed that KDM1A-KO resulted in enhanced ERβ signaling and that genes altered by KDM1A-KO and ERβ agonist were related to apoptosis, cell cycle, and EMT. Moreover, combination treatment significantly reduced the tumor growth in OCa orthotopic, syngeneic, and patient-derived xenograft models and proliferation in patient-derived explant models. Our results demonstrate that KDM1A regulates ERβ expression/functions, and its inhibition improves ERβ mediated tumor suppression. Overall, our findings suggest that KDM1Ai and ERβ agonist combination therapy is a promising strategy for OCa.

Estrogen receptor alpha mediates 17β-estradiol, up-regulates autophagy and alleviates hydrogen peroxide-induced vascular senescence

Atherosclerosis threatens human health by developing cardiovascular diseases, the deadliest disease world widely. The major mechanism contributing to the formation of atherosclerosis is mainly due to vascular endothelial cell (VECs) senescence. We have shown that 17β-estradiol (17β-E2) may protect VECs from senescence by upregulating autophagy. However, little is known about how 17β-E2 activates the autophagy pathway to alleviate cellular senescence. Therefore, the aim of this study is to determine the role of estrogen receptor (ER) α and β in the effects of 17β-E2 on vascular autophagy and aging through in vitro and in vivo models. Hydrogen peroxide (H2O2) was used to establish Human Umbilical Vein Endothelial Cells (HUVECs) senescence. Autophagy activity was measured through immunofluorescence and immunohistochemistry staining of light chain 3 (LC3) expression. Inhibition of ER activity was established using shRNA gene silencing and ER antagonist. Compared with ER-β knockdown, we found that knockdown of ER-α resulted in a significant increase in the extent of HUVEC senescence and senescence-associated secretory phenotype (SASP) secretion. ER-α-specific shRNA was found to reduce 17β-E2-induced autophagy, promote HUVEC senescence, disrupt the morphology of HUVECs, and increase the expression of Rb dephosphorylation and SASP. These in vitro findings were found consistent with the in vivo results. In conclusion, our data suggest that 17β-E2 activates the activity of ER-α and then increases the formation of autophagosomes (LC3 high expression) and decreases the fusion of lysosomes with autophagic vesicles (P62 low expression), which in turn serves to decrease the secretion of SASP caused by H2O2 and consequently inhibit H2O2-induced senescence in HUVEC cells.

Sex steroid receptors in the ovarian follicles of the lizard Sceloporus torquatus

Estradiol and progesterone have been recognized as important mediators of reproductive events in the female mainly via binding to their receptors. This study aimed to characterize the immunolocalization of the estrogen receptor alfa (ERα), estrogen receptor beta (ERβ) and progesterone receptor (PR) in the ovarian follicles of the lizard Sceloporus torquatus. The localization of steroid receptors has a spatio-temporal pattern that depends on the stage of follicular development. The immunostaining intensity of the three receptors was high in the pyriform cells and the cortex of the oocyte of previtellogenic follicles. During the vitellogenic phase, the granulosa and theca immunostaining was intense even with the modification of the follicular layer. In the preovulatory follicles, the receptors were found in yolk and additionally, ERα was also located in the theca. These observations suggest a role for sex steroids in regulating follicular development in lizards, like other vertebrates.

Estrogen receptor beta expression in triple negative breast cancers is not associated with recurrence or survival

BACKGROUND

Triple negative BCa (TNBC) is defined by a lack of expression of estrogen (ERα), progesterone (PgR) receptors and human epidermal growth factor receptor 2 (HER2) as assessed by protein expression and/or gene amplification. It makes up ~ 15% of all BCa and often has a poor prognosis. TNBC is not treated with endocrine therapies as ERα and PR negative tumors in general do not show benefit. However, a small fraction of the true TNBC tumors do show tamoxifen sensitivity, with those expressing the most common isoform of ERβ1 having the most benefit. Recently, the antibodies commonly used to assess ERβ1 in TNBC have been found to lack specificity, which calls into question available data regarding the proportion of TNBC that express ERβ1 and any relationship to clinical outcome.

METHODS

To confirm the true frequency of ERβ1 in TNBC we performed robust ERβ1 immunohistochemistry using the specific antibody CWK-F12 ERβ1 on 156 primary TNBC cancers from patients with a median of 78 months (range 0.2-155 months) follow up.

RESULTS

We found that high expression of ERβ1 was not associated with increased recurrence or survival when assessed as percentage of ERβ1 positive tumor cells or as Allred > 5. In contrast, the non-specific PPG5-10 antibody did show an association with recurrence and survival.

CONCLUSIONS

Our data indicate that ERβ1 expression in TNBC tumours does not associate with prognosis.

Distribution of estrogen receptors alpha and beta in the brain of male rats with same-sex preference

Two distinct estrogen receptors (ERs) exist, ERα and ERβ. Both receptors participate in the sexual differentiation of the rat brain and likely participate in the regulation of adult sexual orientation (i.e. partner preference). This last idea was investigated herein by examining males treated with the aromatase inhibitor, letrozole, administered prenatally (0.56 μg/kg G10-22). This treatment usually provokes same-sex preference in 1-2 males per litter. Vehicle-treated males (with female preference) and females in spontaneous proestrus (with male preference) were included as controls. ERα and ERβ expression was analyzed by immunohistochemistry in brain areas known to control masculine sexual behavior and partner preference, like the medial preoptic area (MPOA), bed nucleus of the stria terminalis (BNST), medial amygdala (MeA) and ventromedial hypothalamic nucleus (VMH), as well as other brain regions suspected to participate in these processes. In addition, serum levels of estradiol were determined in all male groups. Letrozole-treated male rats that preferred sexually experienced males (LPM) showed over-expressed ERα in the hippocampal cornu Ammonis (CA 1, 3, 4) and dentate gyrus. The LPM group showed up-regulated ERβ expression in the CA2 and reticular thalamic nucleus. The levels of estradiol did not differ between the groups. The higher expression of ERs in these males was different than their expression in females, with male sex-preference. This suggests that males with same-sex preference showed a unique brain, this sui generis steroid receptor expression probably participates in the biological underpinnings of sexual preference.

Sexual dimorphism in reactive oxygen species production and a role for integrin α1β1 in estrogen receptor α and β expression in articular cartilage

BACKGROUND

Osteoarthritis (OA) is a debilitating disease involving cartilage degradation. A need remains for the discovery of new molecular targets in cartilage for pharmaceutical intervention of OA. One potential target is integrin α1β1 that protects against OA when it is upregulated by chondrocytes early in the disease process. Integrin α1β1 offers this protection by dampening epidermal growth factor receptor (EGFR) signaling, and its effects are more robust in females compared to males. The aim of this study, therefore, was to measure the impact of itga1 on chondrocyte EGFR activity and downstream reactive oxygen species (ROS) production in male and female mice. Furthermore, chondrocyte expression of estrogen receptor (ER) α and ERβ was measured to investigate the mechanism for sexual dimorphism in the EGFR/integrin α1β1 signaling axis. We hypothesized that integrin α1β1 would decrease ROS production and pEGFR and 3-nitrotyrosine expression, with this effect being greater in females. We further hypothesized that chondrocyte expression of ERα and ERβ would be greater in females compared to males, with a greater effect seen in itga1-null compared to wild-type mice.

MATERIALS AND METHODS

Femoral and tibial cartilage of male and female, wild-type and itga1-null mice were processed for ex vivo confocal imaging of ROS, immunohistochemical analysis of 3-nitrotyrosine, or immunofluorescence of pEGFR and ERα and ERβ.

RESULTS

We show that ROS-producing chondrocytes are more abundant in female itga1-null compared to wild-type mice ex vivo; however, itga1 had limited influence on the percent of chondrocytes stained positively for 3-nitrotyrosine or pEGFR in situ. In addition, we found that itga1 influenced ERα and ERβ expression in femoral cartilage from female mice, and that ERα and ERβ were coexpressed as well as colocalized in chondrocytes. Finally, we show sexual dimorphism in ROS and 3-nitrotyrosine production, but surprisingly not in pEGFR expression.

CONCLUSIONS

Together these data highlight sexual dimorphism in the EGFR/integrin α1β1 signaling axis and underline the need for further investigation into the role of ERs in this biological paradigm. Understanding the molecular mechanisms underlying the development of OA is essential for the development of individualized, sex-specific treatments in this age of personalized medicine.

Estrogen receptor beta in the central amygdala regulates the deleterious behavioral and neuronal consequences of repeated social stress in female rats

While over 95% of the population has reported experiencing extreme stress or trauma, females of reproductive age develop stress-induced neuropsychiatric disorders at twice the rate of males. This suggests that ovarian hormones may facilitate neural processes that increase stress susceptibility and underlie the heightened rates of these disorders, like depression and anxiety, that result from stress exposure in females. However, there is contradicting evidence in the literature regarding estrogen's role in stress-related behavioral outcomes. Estrogen signaling through estrogen receptor beta (ERβ) has been traditionally thought of as anxiolytic, but recent studies suggest estrogen exhibits distinct effects in the context of stress. Furthermore, ERβ is found abundantly in many stress-sensitive brain loci, including the central amygdala (CeA), in which transcription of the vital stress hormone, corticotropin releasing factor (CRF), can be regulated by an estrogen response element. Therefore, these experiments sought to identify the role of CeA ERβ activity during stress on behavioral outcomes in naturally cycling, adult, female Sprague-Dawley rats. Rats were exposed to an ethological model of vicarious social stress, witness stress (WS), in which they experienced the sensory and psychological aspects of an aggressive social defeat encounter between two males. Following WS, rats exhibited stress-induced anxiety-like behaviors in the marble burying taskand brain analysis revealed increased ERβ and CRF specifically within the CeA following exposure to stress cues. Subsequent experiments were designed to target this receptor in the CeA using microinjections of the ERβ antagonist, PHTPP, prior to each stress session. During WS, estrogen signaling through ERβ was responsible for the behavioral sensitization to repeated social stress. Sucrose preference, acoustic startle, and marble burying tasks determined that blocking ERβ in the CeA during WS prevented the development of depressive-, anxiety-like, and hypervigilant behaviors. Additionally, brain analysis revealed a long-term decrease of intra-CeA CRF expression in PHTPP-treated rats. These experiments indicate that ERβ signaling in the CeA, likely through its effects on CRF, contributes to the development of negative valence behaviors that result from exposure to repeated social stress in female rats.

Evaluation of tooth eruption rate of incisor teeth in rats with estrogen deficiency

OBJECTIVES

To assess the influence of estrogen deficiency on tooth eruption rate (TER) and gene expression of estrogen receptor alpha and beta (ERα and ERβ) in the odontogenic region of teeth with continuous formation in a rat model.

MATERIALS AND METHODS

Ovariectomies (OVX; n = 25) and sham surgeries (SHAM; n = 25) were performed in female Wistar rats when animals were 25 days old. The TER of the lower incisors, both in impeded (hyperfunction condition) and unimpeded (trimmed incisal edge-hypofunction condition) conditions, was evaluated using standardized digital photographs acquired every 48-72 h for 3 weeks (35th-53rd day of life), using a camera coupled to a stereomicroscope. Quantitative real-time PCR was performed to evaluate the relative gene expression of ERα and ERβ in the odontogenic region.

RESULTS

The OVX group showed a significant reduction in TER when compared to the SHAM group, only in the impeded condition (p = 0.03). There was no statistically significant difference between the groups in ERα gene expression (p = 0.33). ERβ showed a significantly higher gene expression in the OVX group (p ≤ 0.05).

CONCLUSIONS

Estrogen deficiency decreases TER in teeth under impeded condition. Estrogen deficiency also increases ERβ gene expression in the odontogenic region of teeth with continuous formation.

CLINICAL RELEVANCE

Hormonal disturbances affecting estrogen levels can cause alterations in dental formation and teeth eruption.

ERβ overexpression may not be a direct prognostic factor in patients with NSCLC: A meta-analysis

BACKGROUND

Overall survival of non-small cell lung cancer (NSCLC) patients remains disappointingly low. The estrogen receptor (ER) was considered a promising therapeutic target for NSCLC. Numerous studies have linked expression of ERβ to lung cancer outcome. However, results are conflicting regarding the association of ERβ with surviving lung cancer.

METHOD

The aim of this meta-analysis was to evaluate the prognostic aspect of ERβ expression on survival among NSCLC patients. We performed a final analysis of prognostic value of overexpression ERβ on 3500 patients from 18 evaluable studies (from January 1, 2000 to May 1, 2021). The reference category is specified as low ERβ expression levels. Summarized hazard ratios were calculated.

RESULTS

Our study showed that the pooled hazard ratios of ERβ overexpression for overall survival in NSCLC was 0.81 (95% confidence interval (CI): 0.64-1.02, P = 0.07) by univariate analysis and 1.06 (95% CI: 0.83-1.36, P = 0.63) by multivariate analysis. Pooled hazard ratio by univariate analysis in Asian studies was 0.73 (95%CI: 0.59-0.89, P = 0.002). Pooled hazard ratio by univariate analysis was 0.75 (95% CI: 0.61-0.93, P = 0.009) from seven studies reported for nuclear ERβ. No significant results were found in subgroups by multivariate analysis. No significant results were found in studies outside Asia or in studies reported for cytoplasmic ERβ.

CONCLUSION

Our results suggested that expression of ERβ might not be a direct prognostic factor for NSCLC patients. More detailed prospective studies are needed to identify direct prognostic factors in these patients.

The hypothalamic paraventricular nucleus as a central hub for the estrogenic modulation of neuroendocrine function and behavior

Estradiol and hypothalamic paraventricular nucleus (PVN) help coordinate reproduction with body physiology, growth and metabolism. PVN integrates hormonal and neural signals originating in the periphery, generating an output mediated both by its long-distance neuronal projections, and by a variety of neurohormones produced by its magnocellular and parvocellular neurosecretory cells. Here we review the cyto-and chemo-architecture, the connectivity and function of PVN and the sex-specific regulation exerted by estradiol on PVN neurons and on the expression of neurotransmitters, neuromodulators, neuropeptides and neurohormones in PVN. Classical and non-classical estrogen receptors (ERs) are expressed in neuronal afferents to PVN and in specific PVN interneurons, projecting neurons, neurosecretory neurons and glial cells that are involved in the input-output integration and coordination of neurohormonal signals. Indeed, PVN ERs are known to modulate body homeostatic processes such as autonomic functions, stress response, reproduction, and metabolic control. Finally, the functional implications of the estrogenic modulation of the PVN for body homeostasis are discussed.

Crucial role of high-mobility group box 2 in mouse ovarian follicular development through estrogen receptor beta

High-mobility group box 2 (HMGB2) is a chromatin-associated protein that is an important regulator of gene transcription, recombination, and repair processes. The functional importance of HMGB2 has been reported in various organs, including the testis, heart, and cartilage. However, its role in the ovary is largely unknown. In this study, ovary tissues from wild-type (WT) and HMGB2-knock-out (KO) mice were examined by histopathological staining and immunohistochemistry. The ovary size and weight were significantly lower in HMGB2-KO mice than in age-matched WT littermates. Histopathological analysis revealed ovarian atrophy and progressive fibrosis in 10-month-old HMGB2-KO mouse ovaries. Compared to age-matched WT mice, the numbers of oocytes and developing follicles were significantly decreased at 2 months of age and were completely depleted at 10 months of age in HMGB2-KO mice. Immunohistochemistry revealed the expression of HMGB2 in the granulosa cells of developing follicles, oocytes, some corpora lutea, and stromal cells. Importantly, HMGB2-positive cells were co-localized with estrogen receptor beta (ERβ), but not ERα. Estrogen response element-binding activity was demonstrated by southwestern histochemistry, and it was decreased in HMGB2-KO mouse ovaries. Cell proliferation activity was also decreased in HMGB2-KO mouse ovaries in parallel with the decreased folliculogenesis. These results indicated that the depletion of HMGB2 induced ovarian atrophy that was characterized by a decreased ovarian size and weight, progressive fibrosis, as well as decreased oocytes and folliculogenesis. In conclusion, we demonstrated the crucial role of HMGB2 in mouse ovarian folliculogenesis through ERβ expression.

An Optimized ChIP-Seq Protocol to Determine Chromatin Binding of Estrogen Receptor Beta

Estrogen regulates transcription through two nuclear receptors, ERα and ERβ, in a tissue and cellular-dependent manner. Both the receptors bind estrogen and activate transcription through direct or indirect interactions with DNA. Revealing their interactions with the chromatin is key to understanding their transcriptional activities and their biological functions. Chromatin-immunoprecipitation followed by sequencing (ChIP-Seq) is a powerful technique to map protein-DNA interactions at precise genomic locations. The genome-wide binding of ERα has been extensively studied. Similar studies of ERβ, however, have been more difficult, in part due to a lack of endogenous expression in cell lines and lack of specific antibodies. In this chapter, we provide an optimized stepwise ChIP protocol for a well-validated ERβ antibody, which is applicable for ChIP-Seq analysis of cell lines with exogenous expression of ERβ.

Antibody Validation for Estrogen Receptor Beta

Antibodies can cross-react with proteins other than their intended targets, and antibody-based applications can, if not properly validated, lead to flawed interpretations. When evaluating 13 anti-estrogen receptor beta (ERβ) antibodies in 2017, we concluded that only one of them was specific. Applying this antibody in immunohistochemistry of over 44 different normal human tissues and 20 types of cancers revealed ERβ expression in only a few selected tissues. This aligned with mRNA evidence but contradicted a large set of published literature. ERβ protein expression continues to be reported in tissues without clear support by mRNA expression. In this chapter, we describe how ERβ antibodies can be thoroughly validated and discuss selection of well-characterized positive and negative controls. The validation scheme presented is applicable for immunohistochemistry and Western blotting. The protocol includes evaluation of mRNA evidence, use of public databases, assessment of on- and off-target binding, and an optional step for corroboration with immunoprecipitation and mass spectrometry.

Galangin 3-benzyl-5-methylether derivatives function as an adiponectin synthesis-promoting peroxisome proliferator-activated receptor γ partial agonist

The upregulation of adiponectin production has been suggested as a novel strategy for the treatment of metabolic diseases. Galangin, a natural flavonoid, exhibited adiponectin synthesis-promoting activity during adipogenesis in human bone marrow mesenchymal stem cells. In target identification, galangin bound both peroxisome proliferator-activated receptor (PPAR) γ and estrogen receptor (ER) β. Novel galangin derivatives were synthesized to improve adiponectin synthesis-promoting compounds by increasing the PPARγ activity of galangin and reducing its ERβ activity, because PPARγ functions can be inhibited by ERβ. Three galangin 3-benzyl-5-methylether derivatives significantly promoted adiponectin production by 2.88-, 4.47-, and 2.76-fold, respectively, compared to the effect of galangin. The most potent compound, galangin 3-benzyl-5,7-dimethylether, selectively bound to PPARγ (Ki, 1.7 μM), whereas it did not bind to ERβ. Galangin 3-benzyl-5,7-dimethylether was identified as a PPARγ partial agonist in docking and pharmacological competition studies, suggesting that it may have diverse therapeutic potential in a variety of metabolic diseases.

Estrogen receptor beta (ESR2) gene polymorphism and susceptibility to dementia

Strong evidence supports the involvement of sex steroid hormones in the development and progression of dementia. Attention has been largely focused on the association between genetic variants of estrogen receptor alpha (ERα, ESR1) with dementia, although several studies indicate that ERβ is predominantly expressed in the brain. Interestingly, however, a limited number of studies evaluate the role of ERβ (ESR2) in dementia. Therefore, a meta-analysis was conducted to clarify the association between ESR2 genetic polymorphisms and the risk of dementia. All the relevant studies evaluating ESR2 genetic polymorphisms and dementia were identified through online databases. In total, 14 studies including 20,609 subjects were analyzed. Collectively, it was found that a combined data set of ESR2 polymorphisms was not associated with dementia risk. Interestingly, ESR2 rs4986938 polymorphism is significantly associated with dementia in the Asian population (OR = 0.73, 95% CI 0.59-0.91, P = 0.006). The carrier of A allele in rs4986938 exhibits a protective effect against dementia (A vs. G, OR = 0.6633, P = 0.012; AA + GA vs. GG, OR = 0.6499, P = 0.014; GA vs. AA + GG, OR = 0.6672, P = 0.025; GA vs. GG, OR = 0.6617, P = 0.022). In conclusion, our study suggests that ESR2 genetic polymorphisms are not significantly associated with dementia risk. ESR2 rs4986938 may have potential as a genetic marker for dementia in the Asian population. However, further studies need to verify this conclusion.

Estrogen receptor β alleviates inflammatory lesions in a rat model of inflammatory bowel disease via down-regulating P2X7R expression in macrophages

Estrogen receptor beta (ERβ) agonists could inhibit inflammation in animal models of inflammatory bowel disease (IBD). However, the mechanism underlying such effect and the potential role of P2 × 7 receptor (P2X7R) remains unclear. In the present study, we examined whether the effect of ERβ activation in IBD rats was related to P2X7R. Overexpression of ERβ using a recombinant lentivirus in IBD rats improved the IBD-like symptoms, including weight loss, disease activity index (DAI) scores, and inflammatory responses. ERβ agonists DPN and ERB-041 attenuated P2X7R expression in macrophages from colitis rats and in a murine macrophage cell line (RAW264.7) in response to either lipopolysaccharide (LPS) or adenosine triphosphate (ATP). DPN and ERB-041 also blocked increased production of TNF-α, IL-6, and IL-1β in the rectocolon of colitis rats. The two ERβ agonists reversed LPS- and ATP-induced up-regulation of P2X7R and its downstream proteins, including NLRP3, ASC, caspase-1, and pro-IL-1β, in RAW264.7 cells. Also, in both the rectocolon of colitis rats and RAW264.7 cells, ERβ agonists reversed the up-regulation of extracellular regulated protein kinases (ERK), the Janus kinase 2 (JAK2), and signal transducer and activator of transcription 3 (STAT3), but not up-regulation of serine threonine kinase or cAMP-response element binding protein (CREB). Blockade of JAK2 or STAT3 phosphorylation significantly reduced the ability of DPN to down-regulate P2X7R expression and the ability of ERB-041 and DPN to inhibit IL-1β release from RAW264.7 cells. We found that ERβ and P2X7R co-localized in the macrophages of rat rectocolon and in RAW264.7 cells. Deletion of macrophages from colitis rats with clodronate abolished the inhibitory effect of DPN. These results suggest that ERβ plays an important anti-inflammatory role in IBD rats by down-regulating P2X7R expression and inhibiting IL-1β release from macrophages through the JAK2/STAT3 signaling pathway.

Sex hormones regulate lipid metabolism in adult Sertoli cells: A genome-wide study of estrogen and androgen receptor binding sites

Optimal functioning of Sertoli cells is crucial for spermatogenesis which is under tight regulation of sex hormones, estrogen and androgen. Adult rat Sertoli cells expresses estrogen receptor beta (ERβ) and androgen receptor (AR), both of which regulate gene transcription by binding to the DNA. The present study is aimed to acquire a genome-wide map of estrogen- and androgen-regulated genes in adult Sertoli cells. ChIP-Seq was performed for ERβ and AR in Sertoli cells under physiological conditions. 30,859 peaks in ERβ and 9,594 peaks in AR were identified with a fold enrichment >2 fold. Pathway analysis for the genes revealed metabolic pathways to be significantly enriched. Since Sertoli cells have supportive functions and provide energy substrates to germ cells during spermatogenesis, significantly enriched metabolic pathways were explored further. Peaks of the genes involved in lipid metabolism, like fatty acid, glyceride, leucine, and sphingosine metabolism were validated. Motif analysis confirmed the presence of estrogen- and androgen-response elements (EREs and AREs). Moreover, transcript levels of enzymes involved in the lipid metabolic pathways were significantly altered in cultured Sertoli cells treated with estrogen and androgen receptor agonists, demonstrating functional significance of these binding sites. This study elucidates a mechanism by which sex hormones regulate lipid metabolism in Sertoli cells by transcriptionally controlling the expression of these genes, thereby shedding light on the roles of these hormones in male fertility.

Estrogen receptor beta and neural development

The female sex hormone estradiol (E2, 17β-estradiol) has important functions in the developing brain. In addition to regulating sexual differentiation of the brain, E2 participates in the development of brain areas involved in functions unrelated to reproduction, such as cognition. E2 signals mainly thorough two estrogen receptors; estrogen receptor alpha (ERα) and beta (ERβ). While ERα has distinct functions for sexual imprinting of the developing brain, ERβ is considered to participate in the development of brain areas related to cognitive function. In this chapter we will focus on ERβ's role during neural development. We will discuss the contributions of sex chromosomal and sex hormonal effects in this process and place it in relation to recent data on ERβ obtained from stem cell models. Finally, we will discuss the lessons learned from mouse and stem cell models in understanding ERβ's role in neural development and how new stem cell models, by addressing the human relevance, may help to advance our progress in this field.

Motor Function Deficits in the Estrogen Receptor Beta Knockout Mouse: Role on Excitatory Neurotransmission and Myelination in the Motor Cortex

BACKGROUND

Male estrogen receptor beta (ERβ) knockout (BERKO) mice display anxiety and aggression linked to, among others, altered serotonergic signaling in the basolateral amygdala and dorsal raphe, impaired cortical radial glia migration, and reduced GABAergic signaling. The effects on primary motor cortex (M1 cortex) and locomotor activity as a consequence of ERβ loss have not been investigated.

OBJECTIVE

The aim of this study was to determine whether locomotor activity is altered as a consequence of the changes in the M1 cortex.

METHODS

The locomotor activity of male wild-type (WT) and BERKO mice was evaluated using the open-field and rotarod tests. Molecular changes in the M1 cortex were analyzed by RNA sequencing, electron microscopy, electrophysiology, and immunohistological techniques. In addition, we established oligodendrocyte (OL) cultures from WT and BERKO mouse embryonic stem cells to evaluate OL function.

RESULTS

Locomotor profiling revealed that BERKO mice were more active than WT mice but had impaired motor coordination. Analysis of the M1 cortex pointed out differences in synapse function and myelination. There was a reduction in GABAergic signaling resulting in imbalanced excitatory and inhibitory neurotransmission as well as a defective OL differentiation accompanied by myelin defects. The effects of ERβ loss on OL differentiation were confirmed in vitro.

CONCLUSION

ERβ is an important regulator of GABAergic interneurons and OL differentiation, which impacts on adult M1 cortex function and may be linked to increased locomotor activity and decreased motor coordination in BERKO mice.

The phthalate DEHP modulates the estrogen receptors α and β increasing lactotroph cell population in female pituitary glands

Humans are exposed to numerous endocrine disruptors on a daily basis, which may interfere with endogenous estrogens, with Di-(2-ethylhexyl) phthalate (DEHP) being one of the most employed. The anterior pituitary gland is a target of 17β-estradiol (E2) through the specific estrogen receptors (ERs) α and β, whose expression levels fluctuate in the gland under different contexts, and the ERα/β index is responsible for the final E2 effect. The aim of the present study was to evaluate in vivo and in vitro the DEHP effects on ERα and β expression in the pituitary cell population, and also its impact on lactotroph and somatotroph cell growth. Our results revealed that perinatal exposure to DEHP altered the ERα and β expression pattern in pituitary glands from prepubertal and adult female rats and increased the percentage of lactotroph cells in adulthood. In the in vitro system, DEHP down-regulated ERα and β expression, and as a result increased the ERα/β ratio and decreased the percentages of lactotrophs and somatotrophs expressing ERα and β. In addition, DEHP increased the S + G2M phases, Ki67 index and cyclin D1 in vitro, leading to a rise in the lactotroph and somatotroph cell populations. These results showed that DEHP modified the pituitary ERα and β expression in lactotrophs and somatotrophs from female rats and had an impact on the pituitary cell growth. These changes in ER expression may be a mechanism underlying DEHP exposure in the pituitary gland, leading to cell growth deregulation.

Evaluation of the possibility of selective modulation of retinal glucose transporters in diabetic complications: An experimental study

PURPOSE:

To identify the possibility of modulating retinal glucose transporters in diabetic conditions to prevent retinal complications of diabetic retinopathy.

MATERIALS AND METHODS:

In silico and in vitro binding assays were performed to assess the effect of genistein and positive controls (pioglitazone and estradiol) on nuclear receptor estrogen receptor beta and peroxisome proliferator-activated receptor gamma (PPARγ). In vivo effects of compounds were tested on diabetic rats. Structural and functional analysis of retina was performed at 28^th day followed by gene expression analysis of glucose transporters and nuclear receptors. Pioglitazone and genistein levels were analyzed by liquid chromatography with tandem mass spectrometry.

RESULTS:

Genistein showed equi-affinity toward PPARγ in In silico experiments contrary to in vitro findings. In multidose study, their therapeutic effects were observed by analyzing the retinal function. Retinal gene expression studies revealed that both test agents significantly up regulated PPARγ, GLUT4, and down regulated GLUT1. Genistein showed significant up regulation of GLUT4 and down regulation of GLUT1 as compared to PGZ which has been well correlated with the Electroretinography (ERG) outcome.

CONCLUSION:

This study showed the possibility of selective upregulation of GLUT4 (independent of PPARγ activation) in the retina of diabetic rats using genistein. Selective modulation of retinal glucose transporters as therapeutic target in ocular diabetic complications can be possibly explored.

Oestrogen receptors and hypoxia inducible factor 1 alpha expression in abdominal wall endometriosis

RESEARCH QUESTION

What are the protein levels and localization of oestrogen receptors (including ERa, ERb and G protein-coupled oestrogen receptor [GPER]) and hypoxia-inducible factor-1alpha (HIF-1a) in normal control endometrium (COEM) and ectopic endometrium from abdominal wall endometriosis (AWE).

DESIGN

AWE (n = 20) were obtained during surgery; COEM (n = 40) were collected by curettage. All tissues were obtained during the proliferative or secretory phase. Formalin-fixed paraffin-embedded tissues were used for immunohistochemical study for oestrogen receptors and HIF-1a proteins.

RESULT(S)

The expression of oestrogen receptors and HIF-1a in AWE differed from that in the corresponding menstrual cycle phase of COEM. Compared with COEM, ERa and HIF-1a were decreased whereas ERb and GPER were increased in AWE. The greatest difference was in GPER, with increased protein expression in both the cytoplasm and nucleus of endometrial epithelial and stromal cells, as well as a distinct change in localization from cytoplasmic expression to nuclear and cytoplasmic expression, compared with COEM.

CONCLUSIONS

Our data suggest that the expression changes of oestrogen receptors and HIF-1a, especially GPER, are associated with AWE, which may provide new clues to understanding the cause of endometriosis.

Long filopodia and tunneling nanotubes define new phenotypes of breast cancer cells in 3D cultures

Cancer cell invasion into the surrounding extracellular matrix (ECM) takes place when cell-cell junctions are disrupted upon epithelial-to-mesenchymal transition (EMT). Both cancer cell-stroma and cell-cell crosstalk are essential to support the continuous tumor invasion. Cancer cells release microvesicles and exosomes containing bioactive molecules and signal peptides, which are recruited by neighboring cells or carried to distant sites, thus supporting intercellular communication and cargo transfer. Besides this indirect communication mode, cancer cells can develop cytoplasmic intercellular protrusions or tunneling nanotubes (TNTs), which allow the direct communication and molecular exchange between connected distinct cells. Using scanning electron microscopy (SEM) we show for the first time that MDA-MB-231 (high metastatic potential) and shERβ MDA-MB-231 (low metastatic potential) breast cancer cells cultured on fibronectin and collagen type I or 17β-estradiol (E2) develop TNTs and very long flexible filopodia. Interestingly, the less aggressive shERβ MDA-MB-231 cells treated with E2 in 3D collagen matrix showed the highest development of TNTs and filopodia. TNTs were often associated to adhering exosomes and microvesicles surfing from one cell to another, but no filopodia exhibited vesicle-like cytoplasmic structures on their surface. Moreover, E2 affected the expression of matrix macromolecules and cell effectors mostly in the presence of ERβ. Our novel data highlights the significance of matrix substrates and the presence of E2 and ERβ in the formation of cellular protrusion and the production of surface structures, defining novel phenotypes that unravel nodal reports for breast cancer progression.

17β-Estradiol reduces inflammation and modulates antioxidant enzymes in colonic epithelial cells

BACKGROUND/AIMS

Estrogen is known to have protective effect in colorectal cancer development. The aims of this study are to investigate whether estradiol treatment reduces inflammation in CCD841CoN, a female human colonic epithelial cell line and to uncover underlying mechanisms of estradiol effects.

METHODS

17β-Estradiol (E2) effect was measured by Western blot after inducing inf lammation of CCD841CoN by tumor necrosis factor α (TNF-α). Expression levels of estrogen receptor α (ERα) and β (ERβ), cyclooxygenase-2 (COX-2), nuclear factor-κB (NF-κB), heme oxygenase-1 (HO-1), and NAD(P)H-quinone oxidoreductase-1 (NQO-1) were also evaluated.

RESULTS

E2 treatment induced expression of ERβ but did not increase that of ERα. E2 treatment for 48 hours significantly elevated the expression of anti-oxidant enzymes, HO-1 and NQO-1. TNF-α treatment significantly increased the level of activated NF-κB (p < 0.05), and this increase was significantly suppressed by treatment of 10 nM of E2 (p < 0.05). E2 treatment ameliorated TNF-α-induced COX-2 expression and decrease of HO-1 expression. 4-(2-phenyl-5,7-bis(trifluoromethyl) pyrazolo(1,5-a)pyrimidin-3-yl)phenol (PHTPP), antagonist of ERβ, removed the inhibitory effect of E2 in the TNF-α-induced COX-2 expression (p = 0.05).

CONCLUSION

Estrogen seems to inhibit inflammation in female human colonic epithelial cell lines, through down-regulation of NF-κB and COX-2 expression and induction of anti-oxidant enzymes such as HO-1 and NQO-1.

Optimisation of estrogen receptor subtype-selectivity of a 4-Aryl-4H-chromene scaffold previously identified by virtual screening

4-Aryl-4H-Chromene derivatives have been previously shown to exhibit anti-proliferative, apoptotic and anti-angiogenic activity in a variety of tumor models in vitro and in vivo generally via activation of caspases through inhibition of tubulin polymerisation. We have previously identified by Virtual Screening (VS) a 4-aryl-4H-chromene scaffold, of which two examples were shown to bind Estrogen Receptor α and β with low nanomolar affinity and <20-fold selectivity for α over β and low micromolar anti-proliferative activity in the MCF-7 cell line. Thus, using the 4-aryl-4H-chromene scaffold as a starting point, a series of compounds with a range of basic arylethers at C-4 and modifications at the C3-ester substituent of the benzopyran ring were synthesised, producing some potent ER antagonists in the MCF-7 cell line which were highly selective for ERα (compound 35; 350-fold selectivity) or ERβ (compound 42; 170-fold selectivity).

Estrogen receptor β induces autophagy of osteosarcoma through the mTOR signaling pathway

BACKGROUND

Estrogen receptor beta (ERβ) was considered as a tumor-inhibiting factor in estrogen-sensitive malignant tumors. In this study, we intended to investigate whether ERβ was involved in inducing autophagy in osteosarcoma.

METHODS

This is an experimental study. The associations between ERβ and autophagy were detected in osteosarcoma U2-OS cells which were treated with E2, E2 + 2,3-Bis (4-hydroxyphenyl) propionitrile (DPN, ERβ agonists), E2 + DPN + water, E2 + DPN + 3-Methyladenine (3-MA, autophagy inhibitor), respectively. Cell viability and death were detected using cell counting kit 8 assay and flow cytometry, respectively. In addition, the expression of autophagy marker LC3II/I, sequestosome 1 (P62), mammalian target of rapamycin (mTOR), and phosphorylated-mTOR (p-mTOR) was determined by reverse transcription quantitative polymerase chain reaction (RT-qPCR) and Western blotting.

RESULTS

Cell viability was significantly decreased with DPN treatment, while was reversed with 3-MA treatment. DPN treatment decreased living cells proportion and increased cell apoptosis proportion, while 3-MA treatment reversed those changes. However, there were significant differences between the E2 group and the E2 + DPN + 3-MA group for the living cell proportion and cell apoptosis proportion, suggesting apoptosis and autophagy all were induced. In addition, DPN treatment upregulated the LC3II/I expression level and downregulated P62 and mTOR (mRNA level) and p-mTOR (protein level) expression levels.

CONCLUSION

ERβ inhibited the cell viability and mediated cell death by inducing apoptosis and autophagy in osteosarcoma. ERβ-induced autophagy in osteosarcoma was associated with downregulating the P62 expression level and inhibiting mTOR activation.

Transcriptional Activity of an Estrogen Receptor β Subtype in the Medaka Oryzias dancena

In vertebrate reproductive system, estrogen receptor (ER) plays a pivotal role in mediation of estrogenic signaling pathways. In the present study, we report the cDNA cloning, expression analysis, and transcriptional activity of ERβ1 subtype from medaka Oryzias dancena. The deduced O. dancena ERβ1 (odERβ1; 519 amino acids) contained six characteristic A/B to E/F domains with very short activation function 2 region (called AF2). A phylogenetic analysis indicated that odERβ1 was highly conserved among teleost ERβ1 subgroup. A conventional RT-PCR revealed that the odERβ1 transcripts were widely distributed in the multiple tissues, the ovary, brain, gill, intestine, kidney, and muscle. Further, the relatively higher odERβ1 expressions in the ovary and brain were clearly reproduced in RT-qPCR assay. When HA-fused odERβ1 expression vector was transfected into HEK293 cells, an immunoreactivity for odERβ1 was mainly detected in the nucleus part. Finally, an estrogen responsive element driven luciferase reporter assays demonstrated that the transcriptional activity of odERβ1 significantly increased by estradiol-17β (E2) in a dose dependent manner (p<0.05). However, fold-activation of odERβ1 in the presence of E2 was markedly weak, when it compared with those of O. latipes ERβ1. Taken together, these data suggest that odERβ1 represents a functional variant of teleost ERβ subtype and provides a basic tool allowing future studies examining the function of F domain of ERβ1 subtype and expanding our knowledge of ERβ evolution.

Knockdown of PTEN decreases expression of estrogen receptor β and tamoxifen sensitivity of human breast cancer cells

Estrogen receptors (ERs) and the PTEN-Akt-mTor pathway are important growth regulators in human breast cancer cells, which both are known to affect response to tamoxifen therapy. Recently it was reported that ERβ activates PTEN expression and tamoxifen sensitivity of human breast cancer cells. In this study we examined whether expression of ERβ in turn might be affected by tumor suppressor PTEN, analyzed the effect of this interaction on tamoxifen response and the co-expression of both genes in human breast cancer samples. After siRNA-mediated PTEN knockdown, Western blot analysis revealed a reduction of ERβ protein expression by 67.2% in MCF-7 cells and by 73.6% in T-47D cells (both p < 0.01), results which could be verified on the mRNA level. In cells with normal PTEN and ERβ status, after 6 days of treatment with 1 µM 4-OH tamoxifen, E2-driven proliferation was decreased by 64.5% in MCF-7 and by 57.7% in T-47D cells (both p < 0.01). After knockdown of PTEN expression, the same concentration of 4-OH TAM reduced E2-triggered growth only by 34.9% (MCF-7) and by 41.8% (T-47D) (both p < 0.01 vs control siRNA). Importantly, treatment with ERβ agonist DPN (5 nM) significantly decreased the inhibitory effect of a PTEN knockdown on tamoxifen response of both cell lines (p < 0.05). Additionally, Spearmańs rank association analysis of PTEN and ERβ 1 mRNA levels in 115 normal and malignant breast tissue samples revealed a strong positive correlation of both genes (rho = 0.6085, p < 0.0001). The data of previous studies reporting an important role of ERβ in tamoxifen sensitivity and our findings suggest down-regulation of ERβ triggered by PTEN knockdown contributed to the decreased response of breast cancer cells to tamoxifen observed in this study. Our data also suggest expression of ERβ might be maintained by tumor suppressor PTEN in human breast cancer cells.

Estrogen Receptor Expression in Glial Tumors of Iranian Patients: A Single Center Experience

Background & Objective

Gliomas are the most common type of primary intracranial tumors in adults. The expression of estrogen receptors varies in different grades of glial tumors, and some studies have suggested that this expression might have a prognostic value. It seems that estrogen receptor expression negatively correlates with the histological grade of gliomas. In the present study, we aimed to determine the expression of estrogen receptor in different glial tumors in Iranian patients and to find a possible correlation between its expression and the grade of glial tumors.

Methods

The brain tumors pathology reports from 2014 to 2017 in the Pathology Department of Shohaday-e Tajrish Hospital in Tehran, Iran were evaluated and 104 different gliomas: 79 cases of astrocytoma and 25 cases of oligodendroglioma were selected. All the samples were re-evaluated by a neuropathologist in order to accurately determine the tumor grade. The immunohistochemistry was carried out to detect the expression of estrogen receptor alpha and beta on brain tumors.

Results

None of the samples expressed estrogen receptor alpha. In the case of estrogen receptor beta (ERβ), all samples showed various degrees of positivity: 9% weak, 40% moderate, and 51% strong expressions. The level of ERβ expression was found to be conversely correlated with tumor grade.

Conclusion

Our study demonstrated that ERβ is expressed in the majority (if not all) of the glial tumors and its expression was conversely related to the tumor grade. Because of well-tolerability and acceptable adverse effects, ER agonists might be considered as therapeutic agents for the patients with glial tumors.

Optimized immunohistochemical detection of estrogen receptor beta using two validated monoclonal antibodies confirms its expression in normal and malignant breast tissues

PURPOSE

Significant controversy exists regarding the expression patterns of estrogen receptor beta (ERβ) in normal and diseased breast tissue. To address this issue, we have validated two ERβ antibodies, optimized the IHC protocols for both antibodies and now report the expression patterns of ERβ in normal and malignant breast tissues.

METHODS

ERβ antibody specificity was determined using western blot and IHC analysis. ERβ protein expression patterns were assessed via IHC in normal breast tissue and invasive breast carcinoma. Further, we report the detailed protocol of the ERβ IHC assay developed in our CAP/CLIA certified laboratory to provide a standardized method for future studies.

RESULTS

We have confirmed the specificity of two independent ERβ monoclonal antibodies, one that detects total (i.e., full length plus splice variants 2-5, which do not include the ligand binding domain) ERβ protein (PPZ0506) and one that detects only the full-length form, which includes the ligand binding domain, of ERβ (PPG5/10). Using these two antibodies, we demonstrate that ERβ is highly expressed in normal human breast tissue as well as in 20-30% of invasive breast cancers. Further, these two antibodies exhibited similar staining patterns across multiple different tissues and were highly concordant with regard to determining ERβ positivity in breast cancers.

CONCLUSIONS

ERβ protein was shown to be abundant in the majority of normal breast epithelial cells and is present in 20-30% of breast cancers. Use of these two antibodies, along with their standardized IHC protocols, provide a reference for future studies aimed at determining the utility of ERβ as a prognostic and/or predictive biomarker in various tissues of benign or malignant states.

[Effects of metformin on the expression of estrogen synthetase and ER mRNA in uterine leiomyoma tissues]

Objective: To elucidate whether metformin could regulate the mRNA expression level of estrogen synthetase and ER in human uterine leiomyoma tissues. Methods: (1) Seventeen pairs of uterine leiomyoma tissues and adjacent myometrium (>2 cm) were collected from patients underwent hysterectomy in Peking University First Hospital between December 2016 and January 2017. Real-time PCR was used to measure the mRNA expression level of estrogen synthetase [including cytochrome P450 cholesterol side chain cleavage enzyme (P450scc), cytochrome P450 17α-hydroxylase (P450c17), 3-beta-hydroxysteroid dehydrogenase type 2 (3β-HSD-2), 17-beta-hydroxysteroid dehydrogenase type 1 (17β-HSD-1) and aromatase cytochrome P450 (P450arom)] and ER (including ERα and ERβ) in the uterine leiomyoma tissues and adjacent myometrium. (2) Uterine leiomyoma cells derived from uterine leiomyoma tissues were identified by immunocytochemistry method and cultured to the third generation. The treatment groups were cultured with different concentrations of metformin (10, 50 and 100 μmol/L) for 48 hours, and the control group was cultured with deionized water for 48 hours. The mRNA expression level of estrogen synthetase and estrogen receptor subtypes were measured by real-time PCR. Results: (1) P450scc, P450c17, 3β-HSD-2, 17β-HSD-1, P450arom mRNA median expression levels were 112, 4, 13, 42 and 194 in the uterine leiomyoma tissues, and were respectively 114, 5, 11, 32 and 6 in the myometrium. Compared to those of the myometrium, 3β-HSD-2 and P450arom mRNA expression levels in the uterine leiomyoma tissue were significantly higher (P<0.05), while there were no significant change of mRNA expression levels among P450scc, P450c17 and 17β-HSD-1 (P>0.05). ERα and ERβ mRNA median expression levels were 208 and 116 in the uterine leiomyoma tissues, and were 24 and 95 in the myometrium. Compared to that of the myometrium, ERα mRNA level in the uterine leiomyoma tissue was significantly higher (P=0.001), while there were no significant change of ERβ mRNA level (P=0.193). (2) After cultured with different concentrations of metformin (10, 50 and 100 μmol/L), the P450arom mRNA levels in the uterine leiomyoma tissues were 9±4, 8±5 and 8±3 respectively in the treatment groups and was 16±5 in the control group. Compared to that of the control group, P450arom mRNA expression levels in the treatment groups were significantly declined (P<0.05). There were no significant different change of mRNA expression levels among 3β-HSD-2, ERα and ERβ between the treatment groups and the control group (P>0.05). Conclusions: Metformin could down-regulate the mRNA expression level of aromatase in the uterine leiomyoma cells. These results indicate that metformin may inhibit the local estrogen synthesis and therefore suppress the development of uterine leiomyoma.

Localization of estrogen receptor ERα, ERβ and GPR30 on myenteric neurons of the gastrointestinal tract and their role in motility

Estrogen is well known to have a modulatory role on gastrointestinal tract, particularly through its interaction with nuclear estrogen receptors (ERs), alpha and beta (ERα/β). Recent functional studies also indicate that estrogen can activate a G-protein coupled estrogen receptor, GPR30, or GPER1. The present study was designed to identify either the presence or absence of nuclear ERs and GPR30 in the myenteric plexus of the stomach, duodenum, jejunum, ileum and colon of female and male mice. Immunofluorescence staining revealed a high expression of GPR30 in the cytoplasm but not within the nucleus of enteric neurons in female and male mice. ERβ localization was similar to GPR30, where it was expressed in cytoplasm of enteric neurons, but was absent from nuclei, opening up the possibility that ERβ and GPR30 might work together to manifest estrogenic effects. Comparatively, ERα was mainly located in the nuclei of enteric neurons. ERα, ERβ and GPR30 were also expressed in the cytoplasm of glial cells in the stomach and small intestine, but levels were lower in the colon. The expression nuclear:cytoplasm ratio of ERα was higher in male than female mice, which might relate to sex-dependent translocation of ERα from cytoplasm to nucleus in response to known plasma levels of estrogen. A functional study using isolated ileal segments showed that ERα, ERβ and GPR30 are involved in the neuronal-mediated contractions in female tissues, but only ERα was involved in male tissues. This may indicate although expression level was similar between males and females, the downstream mechanisms of ERβ and GPR30 could be different between sexes. The present study provides a rationale for the action of estrogen to modulate gastrointestinal function in health and disease in different sexes.

ERβ activation in obesity improves whole body metabolism via adipose tissue function and enhanced mitochondria biogenesis

OBJECTIVE

Estrogens play a key role in the distribution of adipose tissue and have their action by binding to both estrogen receptors (ER), α and β. Although ERβ has a role in the energy metabolism, limited data of the physiological mechanism and metabolic response involved in the pharmacological activation of ERβ is available.

METHODS

For clinical relevance, non-ovariectomized female mice were subjected to high fat diet together with pharmacological (DIP - 4-(2-(3,5-dimethylisoxazol-4-yl)-1H-indol-3-yl)phenol) interventions to ERβ selective activation. The physiological mechanism was assessed in vivo by magnetic resonance imaging and spectroscopy, and oral glucose and intraperitoneal insulin tolerance test before and after DIP treatment. Liver and adipose tissue metabolic response was measured in HFD + vehicle and HFD + DIP by stable isotope, RNA sequencing and protein content.

RESULTS

HFD-fed females treated with DIP had a tissue-specific response towards ERβ selective activation. The metabolic profile showed an improved fasting glucose level, insulin sensitivity and reduced liver steatosis.

CONCLUSIONS

Our data demonstrate that selective activation of ERβ exerts a tissue-specific activity which promotes a beneficial effect on whole body metabolic response to obesity.

In Vivo Quantitation of Estrogen Receptor β Subtype Expression in Ovarian Surface Epithelium Using Immunofluorescence Profiling and Confocal Microscopy

Immunohistochemistry using formalin-fixed, paraffin-embedded tissue, chromogen label, and light microscopy has traditionally been used to semiquantify estrogen receptor (ER) to guide diagnosis and management of breast cancer. Quantitation of ER for this purpose currently only assesses levels of the ER-alpha subtype. Considerable variability in results reported has been due to protocol and fixation variability, intraobserver and interobserver variability, and different scoring systems and thresholds for scoring ER positivity. Results can also vary with low expression levels of ER. ER-beta expression is reduced in breast and ovarian cancers and requires quantitation.Herein we describe a novel approach to quantifying ERβ using older mouse ovarian surface epithelium, where ERβ is expressed at lower levels than ERα and is therefore harder to detect. We use an antibody highly specific to the ERβ1 isoform, together with immunofluorescence, confocal microscopy, and imaging and statistical software to achieve clear, reproducible, and unbiased quantitation of ERβ.

Expression of estrogen receptor beta correlates with adverse prognosis in resected pancreatic adenocarcinoma

Background

The relevance of estrogen receptor (ER) expression in pancreatic ductal adenocarcinoma (PDAC) is largely unknown. Clinical trials targeting ER with selective estrogen receptor modulators in pancreatic cancer did not show any benefit. Here, we analyze the impact of recently characterized ER isoform beta on survival in a cohort of patients with resected PDAC.

Methods

Eighty-four patients having undergone pancreatic resection for PDAC at a single institution were identified. Tissue microarrays were constructed of archival tumor specimens. The expression of ER beta was determined by immunohistochemistry and quantified by a system established for estrogen receptor expression in breast cancer. ER beta expression was then correlated with clinicopathological parameters, and univariate and multivariate survival analyses were performed.

Results

Nuclear expression of ER beta was found in 31% of tumors. No significant correlation was found between ER beta expression and TNM status, tumor grade, age or sex. Univariate analysis revealed nodal metastasis and the expression of ER beta as factors correlating with a shorter overall survival and disease free survival. When comparing ER beta expression in patients surviving more than 24 months with those who died from the tumor within 12 or 24 months, respectively, a significantly lower ER beta expression was found in the long term survivors. In multivariate analysis, ER beta expression was demonstrated to be an independent predictor of shorter overall survival.

Conclusions

In resected PDAC, expression of ER beta seems to correlate with poor prognosis. These data may help to identify patients who may benefit from additional systemic therapy including selective estrogen receptor modulators.

Effects of long-term dietary administration of estrogen receptor-beta agonist diarylpropionitrile on ovariectomized female ICR (CD-1) mice

Diarylpropionitrile (DPN) is an estrogen receptor-β-specific agonist that has been linked to neuroprotection, preserving cognitive function with age, the suppression of anxiety-like behaviors, inhibition of cancer growth, and other positive properties. We hypothesized that DPN may have pro-longevity properties. DPN was administered via feed at a dose corresponding to approximately 3 mg/kg/day to ovariectomized female mice beginning at 7 months of age. Mice were followed for the duration of their lifespans while monitoring body mass, aspects of behavior, learning, memory, and frailty. DPN-treated mice gained more body mass over the first 2 years of age (17 months of the study). A test of voluntary running behavior at 24 months of age behavior revealed no deficits in DPN-treated mice, which were as likely as control mice to engage in extended bouts of wheel running, and did so at higher average speeds. DPN administration had anxiolytic-like effects when measured using an elevated plus maze at 9 months of age. A mouse frailty index was used to assess age-related changes. The correlation between age and frailty differed between control and DPN-treated mice. Overall, dietary DPN administration had some beneficial effects on the aging phenotype of ovariectomized female mice with few significant detrimental effects.

Role of co-expression of estrogen receptor beta and Ki67 in prostate adenocarcinoma

Purpose

To evaluate the expression of estrogen receptor (ER)-beta and Ki67 in prostate cancer and study their relationship.

Materials and Methods

We analyzed 101 cases of prostate adenocarcinoma diagnosed from January 2011 to June 2015 in 100 patients. Immunohistochemical staining of ER-beta and Ki67 was analyzed according to Gleason score categorized into prognostic groups of 1 to 5. Double-immunofluorescent staining of ER-beta and Ki67 was performed in a total of 20 cases to study the co-expression and the relationship between these markers within the same tumor.

Results

A total of 53 of 101 cases (52.5%) were positive for ER-beta expression. There was a positive correlation whereby a high percentage of ER-beta expression was seen in the higher prognostic groups (groups 4 and 5; p=0.007). High Ki67 expression was observed in the higher prognostic group, whereas low Ki67 or negative expression was found in the lower prognostic group (p<0.001). The majority of cases evaluated with double-immunofluorescent staining (14/20) showed co-expression of ER-beta and Ki67 at the individual cell level.

Conclusions

ER-beta and Ki67 are independent tumor markers in high prognostic groups. Hence, co-expression of ER-beta and Ki67 indicates a more aggressive tumor with a poorer prognosis.

Sex differences in effects of gestational polychlorinated biphenyl exposure on hypothalamic neuroimmune and neuromodulator systems in neonatal rats

Polychlorinated biphenyls (PCBs) are ubiquitous in the environment and exposure to them is associated with immune, endocrine and neural dysfunction. Effects of PCBs on inflammation and immunity are best described in spleen and blood, with fewer studies on neural tissues. This is an important gap in knowledge, as molecules typically associated with neuroinflammation also serve neuromodulatory roles and interact with hormones in normal brain development. The current study used Sprague-Dawley rats to assess whether gestational PCB exposure altered hypothalamic gene expression and serum cytokine concentration in neonatal animals given an immune challenge. Dams were fed wafers containing a mixture of PCBs at an environmentally relevant dose and composition (20 μg/kg, 1:1:1 Aroclor 1242:1248:1254) or oil vehicle control throughout their pregnancy. One day old male and female offspring were treated with an inflammatory challenge (lipopolysaccharide, LPS, 50 μg/kg, sc) or saline vehicle control approximately 3.5 h prior to tissue collection. Across both basal and activated inflammatory states, PCB exposure caused greater expression of a subset of inflammatory genes in the hypothalamus and lower expression of genes involved in dopamine, serotonin, and opioid systems compared to oil controls. PCB exposure also altered reactions to inflammatory challenge: it reversed the normal decrease in Esr2 hypothalamic expression and induced an abnormal increase in IL-1b and IL-6 serum concentration in response to LPS. Many of these effects were sex specific. Given the potential long-term consequences of neuroimmune disruption, our findings demonstrate the need for further research.

Prognostic value of estrogen receptor α and estrogen receptor β in gastric cancer based on a meta-analysis and The Cancer Genome Atlas (TCGA) datasets

PURPOSE

Numbers of studies have demonstrated that estrogen receptor α and estrogen receptor β have been involved in development of gastric cancer. Hence, we analyzed studies and The Cancer Genome Atlas (TCGA) data of ERs expression and perform this meta-analysis to access the association between ERα or ER β and the clinicopathological characteristics, overall survival time, in GC.

METHOD

A literature search was performed in PubMed, Cochrane Library, Web of Science, EMBASE database, and Chinese CNKI. Data on the relationship between ERα or ERβ expression and clinicopathological features were extracted. A TCGA dataset including information of the ERs expression and clinical data of GC patients was analyzed. Pooled odds ratios (ORs) and hazard ratios (HRs) with 95% confidence intervals (CIs) were calculated.

RESULTS

ERα was not associated with cancer risk, lymph node metastasis, infiltration degree, gender, and TNM stage. However, ERβ was negatively associated with lymph node metastasis. ERα expression may be associated with poor prognosis in GC patients.

CONCLUSION

Estrogen receptors may be related to the progression and deterioration of gastric cancer. However, further high-quality studies are needed to provide more reliable evidence.

The protective role of estrogen and estrogen receptors in cardiovascular disease and the controversial use of estrogen therapy

Epidemiologic studies have previously suggested that premenopausal females have reduced incidence of cardiovascular disease (CVD) when compared to age-matched males, and the incidence and severity of CVD increases postmenopause. The lower incidence of cardiovascular disease in women during reproductive age is attributed at least in part to estrogen (E2). E2 binds to the traditional E2 receptors (ERs), estrogen receptor alpha (ERα), and estrogen receptor beta (ERβ), as well as the more recently identified G-protein-coupled ER (GPR30), and can exert both genomic and non-genomic actions. This review summarizes the protective role of E2 and its receptors in the cardiovascular system and discusses its underlying mechanisms with an emphasis on oxidative stress, fibrosis, angiogenesis, and vascular function. This review also presents the sexual dimorphic role of ERs in modulating E2 action in cardiovascular disease. The controversies surrounding the clinical use of exogenous E2 as a therapeutic agent for cardiovascular disease in women due to the possible risks of thrombotic events, cancers, and arrhythmia are also discussed. Endogenous local E2 biosynthesis from the conversion of testosterone to E2 via aromatase enzyme offers a novel therapeutic paradigm. Targeting specific ERs in the cardiovascular system may result in novel and possibly safer therapeutic options for cardiovascular protection.

The nuclear receptor ERβ engages AGO2 in regulation of gene transcription, RNA splicing and RISC loading

BACKGROUND

The RNA-binding protein Argonaute 2 (AGO2) is a key effector of RNA-silencing pathways It exerts a pivotal role in microRNA maturation and activity and can modulate chromatin remodeling, transcriptional gene regulation and RNA splicing. Estrogen receptor beta (ERβ) is endowed with oncosuppressive activities, antagonizing hormone-induced carcinogenesis and inhibiting growth and oncogenic functions in luminal-like breast cancers (BCs), where its expression correlates with a better prognosis of the disease.

RESULTS

Applying interaction proteomics coupled to mass spectrometry to characterize nuclear factors cooperating with ERβ in gene regulation, we identify AGO2 as a novel partner of ERβ in human BC cells. ERβ-AGO2 association was confirmed in vitro and in vivo in both the nucleus and cytoplasm and is shown to be RNA-mediated. ChIP-Seq demonstrates AGO2 association with a large number of ERβ binding sites, and total and nascent RNA-Seq in ERβ + vs ERβ - cells, and before and after AGO2 knock-down in ERβ + cells, reveals a widespread involvement of this factor in ERβ-mediated regulation of gene transcription rate and RNA splicing. Moreover, isolation and sequencing by RIP-Seq of ERβ-associated long and small RNAs in the cytoplasm suggests involvement of the nuclear receptor in RISC loading, indicating that it may also be able to directly control mRNA translation efficiency and stability.

CONCLUSIONS

These results demonstrate that AGO2 can act as a pleiotropic functional partner of ERβ, indicating that both factors are endowed with multiple roles in the control of key cellular functions.

Estrogen receptor beta as epigenetic mediator of miR-10b and miR-145 in mammary cancer

Even though the role of estrogen receptor alpha (ERα) in the modulation of breast cancer cells' behavior is thoroughly studied, the biological functions of its isoform, ERβ, are less elucidated. The suppression of ERβ in the aggressive ERα-negative MDA-MB-231 breast cancer cells resulted in the inhibition of epithelial to mesenchymal transition (EMT) and major changes in the basic functional properties and expression levels of certain matrix components of breast cancer cells. This arrest in metastatic potential of breast cancer cells suggests the contribution of ERβ in the induction of a more aggressive phenotype in MDA-MB-231 breast cancer cells. The epigenetic alterations are responsible for the ability of the tumor cells to metastasize. Here, we report for the first time that the suppression of ERβ in MDA-MB-231 breast cancer cells leads to significant changes in the expression profiles of specific microRNAs, including miR-10b, miR-200b and miR-145. Growth of MCF-7 and MDA-MB-231 cells in estrogen-free medium has a diverse impact on miRNA expression and the behavior of these cells, suggesting the specific effect of estradiol on the miRNA expression profile depending on the ER status of breast cancer cells. Enhanced miR-10b expression or silencing of miR-145 clearly revealed that these microRNAs can regulate the functional properties, EMT program and the expression of major matrix components known to be implicated in breast cancer aggressiveness. Our data revealed that miR-10b is strongly implicated in the regulation of functional properties, EMT program and Erk1/2 signaling in shERβ MDA-MB-231 cells, thus affecting the extracellular matrix (ECM) composition, including syndecan-1, proteolytic behavior, especially MMP2, MMP7 and MMP9 expression and subsequently the aggressiveness of these cells. Accordingly, the inhibition of miR-145 expression significantly increased the aggressiveness of shERβ MDA-MB-231 cells and induced EMT. Moreover, miR-145 inhibition resulted in important changes in the gene and protein levels of ECM mediators, such as HER2 and several MMPs, whereas it significantly increased the phosphorylated levels of Erk1/2 kinases in these cells, suggesting the crucial role of miR-145 in this signaling pathway. These novel results suggest that the alterations in cell behavior and in ECM composition caused by the suppression of ERβ in MDA-MB-231 cells are closely related to certain epigenetic miRNA-induced alterations. Targeting the ERβ-regulated miR-10b and miR-145 is a promising tool for diagnosis and pharmaceutical targeting in breast cancer.