ERα Protein Expression Research Articles

Spatial and temporal changes in the expression of steroid hormone receptors in mouse model of endometriosis.

Endometriosis is recognized as a steroid hormone-dependent disorder. However, controversies exist regarding the status of the steroid hormone receptor expression in endometriotic tissues. The purpose of this study was to determine the ontogeny of cellular changes in the expression of estrogen receptors (ERα, ERβ), G protein-coupled estrogen receptor 1 (GPER1), and progesterone receptors (PRs) in endometriosis using a mouse model. We used the autologous uterine tissue transfer mouse model and studied the mRNA and protein expression of ERα, ERβ, GPER1, and PR in ectopic lesions at 2, 4, and 8weeks of induction of endometriosis. As compared to endometrium of controls, in the ectopic endometrium, ERα is reduced while ERβ was elevated in stromal cells; however, Gper1 and PR levels are reduced in both stromal and epithelial cells in a time-specific manner. There is a high inter-animal variation in thelevels of these receptors in ectopic endometrium as compared to controls; the levels also varied by almost 100-fold within the same lesion resulting in "micro-heterogeneity." The expression of all these receptors also deferred between two lesions from the same animal. In the endometriotic tissue, there is extensive inter-animal and intra-lesion heterogeneity in the expression of ERα, ERβ, GPER1, and PR. These changes are not due to the influence of the peritoneal environment but appear to be tissue intrinsic. We propose that the variable outcomes in hormonal therapy for endometriosis could be possibly due to heterogeneity in the expression of steroid hormone receptors in the ectopic endometrium.

Targeted degradation of activating estrogen receptor α ligand-binding domain mutations in human breast cancer.

Studies have identified several estrogen receptor α (ERα) ligand-binding domain (LBD) somatic mutations in endocrine therapy resistant, metastatic ER-positive breast cancers. The most common mutations, Tyr537Ser (Y537S) and Asp538Gly (D538G), are detected in ~ 30% of endocrine resistant metastatic breast cancer patients. These ESR1 mutations induce the agonist conformation of ERα, confer an estrogen-independent phenotype, and promote drug resistance to antiestrogens. ER-positive, estrogen-dependent MCF-7 cells were engineered to express either the Y537S or D538G mutants using CRISPR knock-in (cY537S and cD538G). These cells were used to screen several estrogen receptor degrader (ERD) compounds synthesized using the Proteolysis Targeting Chimeras (PROTAC) method to induce degradation of ERα via the ubiquitin-proteasome pathway. Wild-type MCF-7 and ERα LBD mutant cells were treated with ERD-148 (10pM-1µM) and assayed for cellular proliferation using the PrestoBlue cell viability assay. ERD-148 attenuated ER-dependent growth with IC50 values of 0.8, 10.5, and 6.1nM in MCF-7, cY537S, and cD538G cells, respectively. Western blot analysis showed that MCF-7 cells treated with 1nM ERD-148 for 24h exhibited reduced ERα protein expression as compared to the mutants. The ER-regulated gene, GREB1, demonstrated significant downregulation in parental and mutant cells after 24h of ERD-148 treatment at 10nM. Growth of the ER-negative, estrogen-independent MDA-MB-231 breast cancer cells was not inhibited by ERD-148 at the ~ IC90 observed in the ER-positive cells. ERD-148 inhibits the growth of ER-positive breast cancer cells via downregulating ERα with comparable potency to Fulvestrant with marginal non-specific toxicity.

Expression of Estrogen-Related Receptors in Localized Provoked Vulvodynia.

Eight percent of women suffer from vulvodynia, a chronic pain condition with unknown etiology. Inflammation and dysregulation of estrogen signaling have been suggested to play a role in the pathogenesis of localized provoked vulvodynia (LPV). Therefore, the aim of the study was to analyze protein expression levels of estrogen-related receptors ERRα, ERRß, ERRγ, estrogen receptor (ERα), and progesterone receptor (PRα) and CD3-positive T cells in the vulvar vestibulum obtained from women suffering from LPV in comparison to healthy, unaffected controls. Vulvar vestibulum tissue specimens were obtained from LPV patients (n = 12) who had undergone modified posterior vestibulectomy and from 15 healthy controls. Protein expression of ERRα, ERRß, ERRγ, ERα, and PRα and CD3-positive T cells was analyzed by immunohistochemistry (IHC). Expression of ERRß was significantly more pronounced in samples from LPV compared to healthy controls (p = 0.006). No significant difference in the expression patterns of ERRα, ERRγ, ERα, PRα, or CD3 cells was detected. To our knowledge, this is the first study reporting ERR expression in normal vestibulum and in vestibulectomy samples from LPV patients. The higher level of ERRß expression detected by IHC may reflect dysregulation of estrogen signaling in LPV.

17β-estradiol binding to ERα promotes the progression of prolactinoma through estrogen-response element-induced CaBP-9k up-regulation.

17β-estradiol (E2) is considered to be an important instigator of prolactinoma, and can positively regulate the expression of calbindin-D9k (CaBP-9k) which contains an estrogen responsive element (ERE) via estrogen receptors (ERs). However, the detailed mechanism of E2 in promoting CaBP-9k expression and their roles in prolactinoma progression remain unclear. Here, we aimed to characterize it. The luciferase gene reporter assay with luc-ERE transfection showed that E2 treatment significantly enhanced the transcriptional level of CaBP-9k, whereas CaBP-9k activity was reduced when GH3 and MMQ cells were treated with AZD9496, an antagonist of ERα. E2 treatment increased the protein expressions of CaBP-9k and ERα but not ERβ, whereas this effect was also abolished when cells were treated with AZD9496. Besides, immunoprecipitation (IP) and immunofluorescence assays demonstrated that CaBP-9k could directly interact with ERα not ERβ, and Chromatin IP (ChIP) assay showed that ERα could bind to ERE of the CaBP-9k promoter. Moreover, cell counting kit-8 (CCK-8) and flow cytometry assays showed that E2 treatment significantly enhanced cell viability and inhibited cell apoptosis, but these effects were all abolished when ERα was down-regulated by short hairpin RNA (shRNA) or inhibited by AZD9496, as well as CaBP-9K suppression in both GH3 and MMQ cell lines. Taken together, these findings indicated that E2 stimulation promoted prolactin cell proliferation and inhibited cell apoptosis through ERα-induced CaBP-9k up-regulation, which then accelerated the advanced progression of prolactinoma.

Estrogen receptor α/prolactin receptor bilateral crosstalk promotes bromocriptine resistance in prolactinomas.

Prolactinomas are the most common type of functional pituitary adenoma. Although bromocriptine is the preferred first line treatment for prolactinoma, resistance frequently occurs, posing a prominent clinical challenge. Both the prolactin receptor (PRLR) and estrogen receptor α (ERα) serve critical roles in the development and progression of prolactinomas, and whether this interaction between PRLR and ERα contributes to bromocriptine resistance remains to be clarified. In the present study, increased levels of ERα and PRLR protein expression were detected in bromocriptine-resistant prolactinomas and MMQ cells. Prolactin (PRL) and estradiol (E2) were found to exert synergistic effects on prolactinoma cell proliferation. Furthermore, PRL induced the phosphorylation of ERα via the JAK2-PI3K/Akt-MEK/ERK pathway, while estrogen promoted PRLR upregulation via pERα. ERα inhibition abolished E2-induced PRLR upregulation and PRL-induced ERα phosphorylation, and fulvestrant, an ERα inhibitor, restored pituitary adenoma cell sensitivity to bromocriptine by activating JNK-MEK/ERK-p38 MAPK signaling and cyclin D1 downregulation. Collectively, these data suggest that the interaction between the estrogen/ERα and PRL/PRLR pathways may contribute to bromocriptine resistance, and therefore, that combination treatment with fulvestrant and bromocriptine (as opposed to either drug alone) may exert potent antitumor effects on bromocriptine-resistant prolactinomas.

Oroxylin A Reduces Vasoconstriction in Rat Aortic Rings through Promoting NO Production and NOS Protein Expression via Estrogen Receptor Signal Pathway.

Oroxylin A, a flavonoid, is naturally produced in many medicinal plants. Our previous study identified it as a phytoestrogen. Based on this, the present study investigated its vasoconstriction reducing effects and whether the action was mediated by the estrogen receptor (ER) signal pathway. Long-term in vitro treatment with oroxylin A reduced Ach-induced vasorelaxation and NE-mediated or KCl-mediated contractile responses in rat aortic rings. These effects were interfered by an ER inhibitor ICI 182,780. Rat cardiac microvascular endothelial cells (CMECs) and aortic vascular smooth muscle cells (VSMCs) were used to study the possible underlying mechanisms. Oroxylin A activated the ER signal pathway. In CMECs, it increased NO production and eNOS protein expression. In VSMCs, it promoted NO production and iNOS protein expression. These effects were also inhibited by ICI 182,780. Besides, oroxylin A stimulated ERα and ERβ protein expression in CMECs and VSMCs. All these findings suggest that the ER signal pathway takes part in the vasoconstriction reducing effects of oroxylin A.

Sweroside promotes osteoblastic differentiation and mineralization via interaction of membrane estrogen receptor-α and GPR30 mediated p38 signalling pathway on MC3T3-E1 cells

BackgroundDipsaci Radix has been clinically used for thousands of years in China for strengthening muscles and bones. Sweroside is the major active iridoid glycoside isolated from Dipsaci Radix. It has been reported that sweroside can promote alkaline phosphatase (ALP) activity in both the human osteosarcoma cell line MG-63 and rat osteoblasts. However, the underlying mechanism involved in these osteoblastic processes is poorly understood. PurposeThis study aimed to characterize the bone protective effects of sweroside and to investigate the signaling pathway that is involved in its actions in MC3T3-E1 cells. MethodsCell proliferation, differentiation and mineralization were evaluated by the 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) assay, ALP test and Alizarin Red S staining, respectively. The concentration of sweroside in intracellular and extracellular fluids was determined by ultra-performance liquid chromatography coupled to triple quadrupole xevo-mass spectrometry (UPLC/TQ-XS-MS). Proteins associated with the osteoblastic signaling pathway were analysed by western blot and immunofluorescence methods. ResultsSweroside did not obviously affect the proliferation but significantly promoted the ALP activity and mineralization of MC3T3-E1 cells. The maximal absorption amount 0.465 ng/ml (1.3 × 10−9 M) of sweroside was extremely lower than the tested concentration of 358.340 ng/ml (10−6 M), indicating an extremely low absorption rate by MC3T3-E1 cells. Moreover, the ALP activity, the protein expression of ER-α and G protein-coupled receptor 30 (GPR30) induced by sweroside were markedly blocked by both the ER antagonist ICI 182780 and the GPR30 antagonist G15. In addition, sweroside also activated the phosphorylation of p38 kinase (p-p38), while the phosphorylation effects together with ALP and mineralization activities were completely blocked by a p38 antagonist, SB203580. Additionally, the phosphorylation of p38 induced by sweroside were markedly blocked by both the ER antagonist ICI 182780 and the GPR30 antagonist G15. ConclusionsThe present study indicated that sweroside, as a potential agent in treatment of osteoporosis, might exert beneficial effects on MC3T3-E1 cells by interaction with the membrane estrogen receptor-α and GPR30 that then activates the p38 signaling pathway. This is the first study to report the specific mechanism of the effects of sweroside on osteoblastic differentiation and mineralization of MC3T3-E1 cells.

Combined Exposure to Fructose and Bisphenol A Exacerbates Abnormal Lipid Metabolism in Liver of Developmental Male Rats.

The aim of this study was to investigate whether combined exposure to fructose and bisphenol A (BPA) has a synergistic effect on abnormal lipid metabolism in the liver of developmental male rats and its possible mechanism. Fifty weaned male Wistar rats were divided into five groups: the control, 13% fructose, 20% fructose, 1 µg/mL BPA, and 13% fructose + 1 µg/mL BPA (combined exposure). Rats were exposed to fructose and/or BPA through drinking water for eight weeks. Genes or proteins regulating lipid metabolism include sterol regulatory element binding protein 1 (SREBP1), adipose triglyceride lipase (ATGL), hormone sensitive lipase (HSL), acetyl-CoA carboxylase 1 (ACC1), fatty acid synthase (FAS), zinc α 2 glycoprotein (ZAG) and estrogen receptor α (ERα), and the expression of proteins regulating inflammatory response, such as TLR4 and NF-κB, were determined. Serum total cholesterol (T-CHO), triglyceride (TG), low, high density lipoprotein cholesterol (LDL-C, HDL-C), blood glucose, insulin, IL-17 and TNF-α levels were also measured. Liver tissue morphology was observed by H&E staining. The results showed that the levels of gene and protein catalyzing lipogenesis were increased (SREBP1, ACC1 and FAS), while those catalyzing lipolysis were decreased (ATGL, HSL and ZAG), accompanied by dyslipidemia, insulin resistance and hepatic fat accumulation, and there were higher expression of TLR4 and NF-κB protein and lower expression of ERα protein in liver, and increased serum IL-17 and TNF-α levels in fructose and/or BPA exposed rats compared with controls. Moreover, the above indicators were more serious in combined exposure group than in single exposure group. Therefore, abnormal lipid metabolism in the liver of developmental rats could be exacerbated by combined exposed to fructose and BPA.

Lifelong n-3 Polyunsaturated Fatty Acid Exposure Modulates Size of Mammary Epithelial Cell Populations and Expression of Caveolae Resident Proteins in Fat-1 Mice.

Omega-3 polyunsaturated fatty acids (n-3 PUFA) have been associated with reduced breast cancer risk; however, the exact mechanism remains elusive. Female wildtype (WT) and fat-1 mice were fed a 10% safflower diet until 6 weeks of age. Mammary gland epithelial cells (EC) were isolated and EC populations were determined by CD24 surface expression. Fat-1 mice expressed 65%, 20%, and 15% while WT mice expressed 65%, 26% and 9% for non-, myo- and luminal ECs, respectively. The luminal EC population was significantly greater in fat-1 mice (p ≤ 0.05), while the total number of mammary ECs were similar between groups (p = 0.79). Caveolae was isolated from ECs and Her-2/neu, ER-α and cav-1 protein expression was determined by Western blotting. Fat-1 mice had a two-fold greater ER-α (p ≤ 0.05) and a 1.5-fold greater cav-1 (p ≤ 0.05) expression than WT with a similar amount of Her-2/neu protein (p = 0.990) between groups. Overall, this study provides novel mechanistic evidence by which n-3 PUFA modifies early mammary gland development that may potentially reduce breast cancer risk later in life.

Disocin prevents postmenopausal atherosclerosis in ovariectomized LDLR-/- mice through a PGC-1α/ERα pathway leading to promotion of autophagy and inhibition of oxidative stress, inflammation and apoptosis

Atherosclerosis (AS) is one of the major causes leading to mortality of dysfunctional cardiovascular events in the menopausal women, which has long-term deficiency of estrogen. At present, the primary treatment for postmenopausal AS is hormone replacement therapy (HRT). However, it can increase the risks of ovarian and uterine cancers with long-term therapy. So seeking for a phytoestrogen which can overcome the disadvantages of HRT is a great mission. Dioscin, a traditional Chinese medicine, extracted from the roots of dioscorea nipponica, has anti-inflammatory, anti-tumor and anti-apoptosis activities. Especially, it also has estrogenic activity. Thus, this study aims to investigate the effects of dioscin on postmenopausal AS. Currently, ovariectomy (OVX) is the accepted model for AS associated with estrogen deficiency, and it can mimic the cessation of ovarian function that occurs in postmenopausal women as well. We used the high fat diet and ovariectomy(HFD-OVX)model to induce postmenopausal AS in the low-density lipoprotein receptor- deficient (LDLR-/-) mice. (1) The levels of TG, TC, LDL-C, HDLC, MDA, GSH, MDA and GSH in serum of HFD-OVX induced LDLR-/- mice were measured by colorimetric assay. (2) The artery injury of HFD-OVX induced LDLR-/- mice was detected with Oil Red O staining. (3) The protein expressions of NOX4, P22phox, IκB, p-p65, n-p65, ICAM-1, VCAM-1, caspase-3, caspase-9, bcl-2, PGC-1α, ERα, ERβ in the arterial tissue of HFD-OVX induced LDLR-/- mice were detected by Western blot analysis. In vitro, the model of human aortic endothelial cells (HAECs) induced by oxidized low-density lipoprotein (ox-LDL) (150 μg /ml) was established, and the molecular mechanism of dioscin on atherosclerosis in postmenopausal women was investigated. (1) The levels of MDA, GSH, MDA and GSH in ox-LDL induced HAECs were measured by colorimetric assay. (2) Reactive Oxygen Species (ROS) of ox-LDL induced HAEC cells was detected by fluorescence staining. (3) The protein expressions of PGC-1α, ERα, ERβ, NOX4, P22phox, IκB, p-p65, n-p65, ICAM-1, VCAM-1, caspase-3, caspase-9, bcl-2 and LC3 in ox-LDL induced HAECs were detected by Western blot analysis. (4) The autophagy level of ox-LDL induced HAECs was measured by transmission electron microscopy. (5) The applications of si-RNA transfection were used to explore whether dioscin could activate PGC-1α/ERα pathway to inhibit postmenopausal atherosclerosis.In vivo, we found that dioscin decreased the level of TG, TC, LDL-C and increased the level of HDLC in serum of HFD-OVX induced LDLR-/- mice, and it has protective effects to maintain the lipid homeostasis; The Oil Red O staining study showed that dioscin could significantly inhibit the formation of atherosclerotic plaques in HFD-OVX-treated LDLR-/- mice; Dioscin decreased the levels of NOX4, P22phox, p-p65, n-p65, ICAM-1, VCAM-1, caspase-3, caspase-9, but increased the levels of HDL-C, GSH, SOD, PGC-1α, ERα, ERβ, IκB, Bcl-2 and elevated the autophagy level in arterial tissues of HFD-OVX induced LDLR-/- mice. It is particularly worth mentioning that the up-regulating effect of dioscin on ERα is stronger than ERβ in OVX treated mice. In vitro, the results of colorimetric assay showed that dioscin decreased the level of MDA and LDH, increased the level of SOD and GSH in ox-LDL-induced HAEC cells; Dioscin also suppressed the release of ROS in ox-LDL-induced HAECs by fluorescence staining; Dioscin decreased the levels of NOX4, P22phox, p-p65, n-p65, ICAM-1, VCAM-1, caspase-3, caspase-9, but increased the levels of PGC-1α, ERα, ERβ, IκB, Bcl-2 and the ratio of LC3-II/LC3-I in ox-LDL-induced HAECs; Dioscin significantly elevated the autophagy level of ox-LDL-induced HAECs by transmission electron microscopy analysis; In addition, by si-RNA transfection, we found that the inhibitory effects of dioscin on oxidative stress, inflammatory response and apoptosis might partly through PGC-1α/ERα pathway in ox-LDL induced HAECs. The data of dual-Luciferase reporter assay revealed that dioscin activated ERα at least partly through PGC-1α pathway.Dioscin significantly inhibited oxidative stress, inflammatory response, apoptosis and increased the level of autophagy in vivo and vitro. In addition, dioscin could regulate the balance of lipid metabolism. Moreover, we proved that the effects of dioscin attenuating postmenopausal atherosclerosis by inhibiting oxidative stress, inflammation and apoptosis were partly dependent on PGC-1α/ERα pathway. Therefore, dioscin, as a phytoestrogen, might become a drug for the treatment of atherosclerosis in postmenopausal women.

DHT and E2 synthesis-related proteins and receptors expression in male yak skin during different hair follicle stages

Dihydrotestosterone (DHT) and 17β-estradiol (E2) are sex hormones that regulate human hair follicle (HF) growth and are produced by peripheral reduction and aromatization of testosterone. However, the expression patterns of DHT and E2 synthesis-related proteins and their receptors in male yak skin during different HF stages (telogen, anagen, and catagen) are unknown. In this study, we found that both 5α-red and androgen receptor (AR) were expressed in epithelial cells and AR was expressed in the dermal papilla. Additionally, the transcription level of 5α-red1 at different HF stages was significantly higher than that of 5α-red2 mRNA at the same stage; 5α-red1 and 5α-red2 proteins peaked during the anagen and telogen periods of HF, respectively. However, AR protein was only expressed in the skin during the anagen phase of HF. Aromatase and estrogen receptors (ERα and ERβ) were expressed in cutaneous epithelial cells, whereas ERα and ERβ were expressed in the dermal papilla; the transcription level of ERα in HFs at each stage was much higher than that of ERβ. From the catagen to telogen phase, aromatase protein expression was down-regulated, while ERα protein expression was up-regulated. Based on our results, we speculate that 5α-red1 is essential for the synthesis of DHT in male yak skin epithelial cells and promotes the growth of HFs through AR. E2 synthesized by male yak skin epithelial cells may inhibit the growth of male yak skin HFs by ERα. These results provide a foundation for further study on the mechanism of hormone-regulated male yak skin HFs.

Impact of gestational low protein diet and postnatal bisphenol A exposure on chemically induced mammary carcinogenesis in female offspring rats.

This study evaluated the effect of gestational low protein diet (LPD) and/or postnatal bisphenol A (BPA) exposure on mammary gland development and carcinogenesis in female offspring. Pregnant Sprague-Dawley rats were fed a normal protein diet (NPD, 17% protein) or LPD (6% protein). At weaning, female offspring were distributed in four groups (NPD, LPD, NPD + BPA, and LPD + BPA) and received vehicle or BPA in drinking water (0.1%), during postnatal day (PND) 21 to 51. On PND 51, some female offspring were euthanized or received a single dose of 7,12-dimethylbenzoanthracene (DMBA, 30 mg/kg, i.g.) and were euthanized on PND 250. On PND 51, neither gestational LPD nor postnatal BPA exposure, individually or in combination, significantly altered the development of mammary gland tree, mean number of terminal structures or estrogen receptor beta (ER-β), proliferating cell nuclear antigen (PCNA) or caspase-3 protein expression in the mammary tissue. A significant reduction in mammary epithelial area (%) was observed in both LPD groups and a significant increase in ER-α protein expression was detected only in LPD group. In LPD + BPA group was observed a significant increase in both fat pad area (%) and in mean number of mammary epithelial cells positive for progesterone receptor (PR). On PND 250, the groups that received BPA presented lower latency and higher tumor incidence and tumor multiplicity and LPD + BPA group more aggressive tumors. These findings suggest that postnatal BPA exposure associated with gestational LPD is able to induce morphological changes in the mammary gland and increase susceptibility to mammary carcinogenesis.

Abstract 4320: Enhanced expression of histone methyltransferases increase ERα expression in tamoxifen-resistant breast cancer cells

Abstract Estrogen receptor (ER)-positive breast cancers depend on ER signaling for growth and progression. Although tamoxifen remains the frontline treatment for such cancers, resistance to this drug limits its clinical efficacy. Nevertheless, the majority of tamoxifen-resistant patients retain ERα expression, providing a rationale for targeting ERα in these patients. Here, we found that the expression of mixed lineage leukemia (MLL) family proteins are increased in tamoxifen-resistant breast cancer cells and patients. Specifically, mixed lineage leukemia 3 (MLL3) and SET domain containing 1A (SET1A) depletion downregulated the expression of ERα protein and mRNA levels in a ER-positive breast cancer cell. Chromatin Immunoprecipitation analysis revealed that the knock-down of MLL3 and SET1A reduce the histone H3K4 methylation status in ESR1 promoter regions. We also observed the positive correlation between ERα level and MLL3/SET1A level in breast cancer clinical data sets. Importantly, MLL3 and SET1A depletion downregulated the ERα and its downstream growth-related protein levels, as well as the growth of both ER-positive and tamoxifen-resistant breast cancer cells. Likewise, MLL3 and SET1A knockdown decreased the proportion of cells entering the cell cycle. Additional fulvestrant treatment resulted in synergistic reduction of ERα levels and growth of the tamoxifen-resistant breast cancer cells. Thus, enhanced expression of MLL3 and SET1A in tamoxifen-resistant breast cancer cells supported ERα-dependent growth of breast cancer cells, suggesting that MLL3 SET1A might provide an attractive target for overcoming endocrine resistance. Citation Format: Seungsu Kim, Min-Ho Lee, Mi-Ock Lee. Enhanced expression of histone methyltransferases increase ERα expression in tamoxifen-resistant breast cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4320.

Increased expression of the HDAC9 gene is associated with antiestrogen resistance of breast cancers.

Estrogens play a pivotal role in breast cancer etiology, and endocrine therapy remains the main first line treatment for estrogen receptor‐alpha (ERα)‐positive breast cancer. ER are transcription factors whose activity is finely regulated by various regulatory complexes, including histone deacetylases (HDACs). Here, we investigated the role of HDAC9 in ERα signaling and response to antiestrogens in breast cancer cells. Various Michigan Cancer Foundation‐7 (MCF7) breast cancer cell lines that overexpress class IIa HDAC9 or that are resistant to the partial antiestrogen 4‐hydroxy‐tamoxifen (OHTam) were used to study phenotypic changes in response to ER ligands by using transcriptomic and gene set enrichment analyses. Kaplan–Meier survival analyses were performed using public transcriptomic datasets from human breast cancer biopsies. In MCF7 breast cancer cells, HDAC9 decreased ERα mRNA and protein expression and inhibited its transcriptional activity. Conversely, HDAC9 mRNA was strongly overexpressed in OHTam‐resistant MCF7 cells and in ERα‐negative breast tumor cell lines. Moreover, HDAC9‐overexpressing cells were less sensitive to OHTam antiproliferative effects compared with parental MCF7 cells. Several genes (including MUC1, SMC3 and S100P) were similarly deregulated in OHTam‐resistant and in HDAC9‐overexpressing MCF7 cells. Finally, HDAC9 expression was positively associated with genes upregulated in endocrine therapy‐resistant breast cancers and high HDAC9 levels were associated with worse prognosis in patients treated with OHTam. These results demonstrate the complex interactions of class IIa HDAC9 with ERα signaling in breast cancer cells and its effect on the response to hormone therapy.

PF516 ESTROGEN BETA RECEPTOR: A NEW TARGET FOR DIFFUSE LARGE B‐CELL LYMPHOMA

Background:About 40% of DLBCL patients do not respond to immuno‐chemotherapy and have a poor prognosis, underscoring the need for alternative treatment approaches. Using an unbiased genome‐wide guilt‐by‐association approach we identified the estrogen receptor beta (ERβ) as a possible new target in DLBCL. ERβ can serve as a target for selective ER modulators such as tamoxifen. Tamoxifen is one of the most widely used anticancer drugs, with a history of more than 4 decades of safe clinical use.Aims:To investigate whether ERβ and tamoxifen could serve as a therapeutic target‐drug combination in DLBCL.Methods:Publically available mRNA (Gene expression omnibus) and RNA sequence data (GEPIA) were consulted to study ERβ expression DLBCL and normal B cells. Nanostring was used to establish ERβ mRNA expression in lymphoma cell lines. ERβ and estrogen receptor α (ERα) protein expression were determined using Western Blot (WB) on DLBCL cell lines. Cell viability and apoptosis assays were performed after treatment with tamoxifen, endoxifen, the selective ERβ agonist DPN and the selective ERβ antagonist PHTPP. BH3 profiling was used to study changes in the anti‐apoptotic dependencies for cell lines and patient samples after treatment with tamoxifen. NSG mice were transplanted with DLBCL cell lines and the treatment group was treated with 60‐day release tamoxifen pellets subcutaneously. A nationwide, population based study was consulted to assess DLBCL incidence in patients with breast cancer (BC) treated with or without tamoxifen between 2007 and 2017.Results:ERβ mRNA and RNA seq expression was found to be significantly higher in DLBCL compared to normal B‐cells, and mRNA expression was found to be high in DLBCL compared to other lymphoma cell lines. All DLBCL cell lines expressed ERβ at the protein level, but no ERα. Treatment of DLBCL cell lines with the selective ER modulators tamoxifen and its active metabolite endoxifen dose‐dependently induced apoptosis in all DLBCL cell lines. The selective ERβ antagonist PHTPP also caused cell death, while DPN had no effect. Treatment with tamoxifen induced a BAD‐dependent apoptotic signal and increased anti‐apoptotic dependency for the anti‐apoptotic protein BCL‐2 in both cell lines and patient‐derived DLBCL cells. In our DLBCL mouse model, DLBCL outgrowth was significantly decreased in mice treated with tamoxifen compared to control mice, leading to a significant improved survival (HR 3.9, p = 0.007). To study the clinical relevance of tamoxifen, we investigated the DLBCL incidence in BC patients treated with or without tamoxifen. Of 153,883 patients, 106 patients (0.07%) were diagnosed with both BC and DLBCL. Interestingly, 82 patients (77%) received no tamoxifen treatment, resulting in a relative risk reduction of 38% (p < 0.05) for tamoxifen treated patients.Summary/Conclusion:ERβ is highly expressed in DLBCL. Targeting of ERβ with tamoxifen treatment causes a dose‐dependent decrease in cell viability and induces BAD dependent apoptosis in all DLBCL cell lines. Targeting ERβ with tamoxifen as a treatment for DLBCL, especially considering low costs and limited side effects, would implicate great clinical potential.image

The Effect of Rutin on Progesterone and Estrogen Receptor Expression in Uterine Endometrial Tissue in the Heterotopic Transplantation of Newborn Mouse Ovary

Background: Rutin (quercetin-3-rhamnosyl-glucoside), a flavonoid, is derived from plants and has antioxidant properties. Objectives: This study aimed to evaluate the effect of different concentrations of rutin on mouse ovary heterotopic allotransplantation. Methods: The present animal experimental study was conducted on 40 female adult Balb/c mice weighing 30 ± 5 g at the Jundishapur University of Medical Sciences, Ahvaz, Iran, during 2016 - 2018. The mice were divided by permuted block randomization into 8 groups (n = 5): OVX (ovariectomy), as the negative control; normal (positive control); OVX + OVA (ovariectomy and transplantation) (control), treated with 0.5 mL of normal saline; OVX + OVA + 10 mg/kg of rutin; OVX + OVA + 30 mg/kg of rutin; OVX + OVA + 60 mg/kg of rutin; OVX + OVA + 100 mg/kg of rutin; and the autograft. Groups were treated daily. Fourteen days after transplantation, ovarian grafts were collected and processed histologically for follicle number counting. Serum estrogen (E2) and progesterone (P4) levels were evaluated. Furthermore, the expression of Estrogen Receptor alpha (ERα), Estrogen Receptor beta (ERβ), and Progesterone Receptor (PR) in the uterine endometrial tissue was tested using qRT-PCR and western blotting. Results: A decrease in the number of mature follicles and increase in the number of atretic follicles (mean ± SD: OVX + OVA + 30 = 19.00 ± 1.000, OVX + OVA + 60 = 25.00 ± 5.000, and OVX + OVA + 100 = 23.00 ± 2.646) were observed in all groups treated with rutin in comparison with the control group (mean ± SD: 12.33 ± 2.517) (P value < 0.05). The level of E2 and P4 (mean ± SD: OVX + OVA + 100 = 6.133 ± 1.026) increased in comparison with the OVX + OVA group (mean ± SD: 0.4667 ± 0.2517) (P value < 0.05). The protein expression of ERα (mean ± SD: OVX + OVA + 10 = 1.615 ± 0.1701 and OVX + OVA + 30 = 1.744 ± 0.1779) in comparison with the control group (mean ± SD: 0.7089 ± 0.1131), and ERβ (mean ± SD: OVX + OVA + 10 = 0.7747 ± 0.4365, OVX + OVA + 30 = 0.9220 ± 0.1245, OVX + OVA + 60 = 0.7701 ± 0.2150, and OVX + OVA + 100 = 0.6676 ± 0.1547) increased in a dose-dependent manner in all groups treated with rutin in comparison with the OVX + OVA group (mean ± SD: 0.1534 ± 0.06109) (P value < 0.05). No significant changes in PR were found in groups treated with rutin in comparison with the control group. Conclusions: The results of the present study indicated that rutin increases E2 and P4 levels in ovarian hetero allograft mice. Rutin also upregulated the expression of ERα and ERβ but had no significant effect on PR.

CCAAT-displacement protein/cut homeobox transcription factor (CUX1) represses estrogen receptor-alpha (ER-α) in triple-negative breast cancer cells and can be antagonized by muscadine grape skin extract (MSKE).

Triple-Negative Breast Cancers (TNBCs) are the most difficult to treat subtype of breast cancer and are often associated with high nuclear expression of Snail and Cathepsin L (Cat L) protease. We have previously shown that Snail can increase Cat L expression/activity in prostate and breast cancer cells. This study investigated the role of CUX1 (a downstream substrate of Cat L) in TNBC. We showed that Cat L and CUX1 were highly expressed in TNBC patient tissue/cell lines, as compared to ER-positive samples, using cBioportal data and western blot/zymography analyses. Additionally, luciferase reporter and chromatin immunoprecipitation assays showed that CUX1 directly bound to estrogen receptor-alpha (ER-α) promoter in MDA-MB-468, a representative TNBC cell line, and that CUX1 siRNA could restore ER-α transcription and protein expression. Furthermore, Snail and CUX1 expression in various TNBC cell lines was inhibited by muscadine grape skin extract (MSKE, a natural grape product rich in anthocyanins) or Cat L inhibitor (Z-FY-CHO) leading to decreased cell invasion and migration. MSKE decreased cell viability and increased expression of apoptotic markers in MDA-MB-468 cells, with no effect on non-tumorigenic MCF10A cells. MSKE also decreased CUX1 binding to ER-α promoter and restored ER-α expression in TNBC cells, while both MSKE and CUX1 siRNA restored sensitivity to estradiol and 4-hydoxytamoxifen as shown by increased cell viability. Therefore, CUX1 activated by Snail-Cat L signaling may contribute to TNBC via ER-α repression, and may be a viable target for TNBC using natural products such as MSKE that targets cancer and not normal cells.

Sex steroid hormone receptor expression in the vaginal wall in cervical cancer survivors after radiotherapy

Background: Sex steroid hormones and their receptors are important in female sexual function. The aim of this study was to investigate the expression and distribution of estrogen receptor (ER)α, ERβ, G-protein-coupled ER-1 (GPER), androgen receptor (AR), progesterone receptor (PR)A, PRB and connective tissue growth factor (CTGF) in the vaginal wall among women who had been treated for cervical cancer with radiotherapy.Material and methods: We included cervical cancer survivors treated with radiotherapy and premenopausal control women of the same age scheduled for benign gynecological surgery. We analyzed the expression and distribution of sex steroid hormone receptors and CTGF in biopsies from the vaginal wall, by real-time PCR and immunohistochemistry (IHC). Serum samples were analyzed for hormone levels and radiation dose at biopsy site were calculated and correlated to levels of the sex steroid hormone receptors.Results: In the cervical cancer survivors (n = 34), we found a lower expression of ERα at both mRNA and protein levels, compared to the control women (n = 37). In the survivors with high radiation dose at biopsy site, the immunostaining of ERα and AR was lower in the epithelium and the stroma, compared to survivors with minimal radiation dose. The later group showed expression of ERα comparable to the control women. The cancer survivors were sufficiently substituted with systemic estradiol with no difference in the serum estradiol levels compared to control women.Conclusions: We found that external radiation reduces the ERα and AR protein expression in the vaginal mucosa, indicating that the vaginal changes in irradiated cervical cancer survivors and the lack of response to hormonal treatment could be due to the decreases in sex steroid hormone receptor expression.

Effects of Resveratrol on the Mechanisms of Antioxidants and Estrogen in Alzheimer's Disease.

Objective To observe the effects of resveratrol (Res) on the antioxidative function and estrogen level in an Alzheimer's disease (AD) mouse model. Methods First, we examined the effects of Res on an AD mice model. SAMP8 mice were selected as the model, and normal-aging SAMR1 mice were used as the control group. The model mice were randomly divided into three groups: a model group, high-dose Res group (40mg/kg, intraperitoneal (ip)), and low-dose Res group (20mg/kg, ip). After receiving medication for 15 days, the mice were subjected to the water maze test to assess their spatial discrimination. The spectrophotometric method was used to detect the activity of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and catalase (CAT) as well as the malondialdehyde (MDA) content. Quantitative PCR (q-PCR) was used to detect SOD, GSH-Px, CAT, and heme oxygenase-1 (HO-1) mRNA level changes. Western blot analysis detected HO-1 and Nrf2 protein expression. Second, we researched the effect of Res on the estrogen level in the SAMP8 model mice. The model mice were randomly divided into four groups: a model group, estrogen replacement group (0.28 mg/kg, intramuscular (im), estradiol benzoate), high-dose Res group (5 mg/kg, im), and low-dose Res group (2.5 mg/kg, im). The mice were injected, once every three days, for 5 weeks. Q-PCR was used to detect brain tissue mRNA expression changes. Western blot analysis detected ERα, ERβ, and ChAT protein expression. An enzyme-linked immunosorbent assay (ELISA) kit was used to detect the expression of E2 and amyloid β protein (Aβ) in brain tissue. Results Compared with the control treatment, Res could improve the spatial abilities of the mice to a certain extent and also increase the expression of SOD, GSH-Px, CAT, and HO-1 at the mRNA level (P<0.05). In addition, enhanced SOD, GSH-Px, and CAT activities and HO-1 protein levels and decreased MDA content (P<0.05) were detected in the brain tissue of the Res-treated mice. The cytoplasmic Nrf2 content in the Res-treated mice was also decreased while the nuclear Nrf2 content and the nuclear translation rate of Nrf2 were increased (P<0.05). Res could decrease the expression of ERβ in the brain tissue at the mRNA and protein levels and the expression of Aβ in the brain tissue at the protein level. Res could also increase the mRNA and protein expression of ERα and ChAT and the protein expression of estradiol in the brain tissue. Conclusion Res can increase the antioxidant capacity of AD models through the Nrf2/HO-1 signaling pathway. In addition, Res can enhance estrogen levels in an AD model. These findings provide a new idea for the treatment of AD.

Differential effects of ambient PAH mixtures on cellular and steroidogenic properties of placental JEG-3 and BeWo cells

We determined the action of a mixture of 16 priority PAHs present in high concentrations in maternal blood (Mix I) and the same but in low concentrations detected in placental tissue (Mix II) on AhR, ERα, NFκB, CYP1A1, CYP1B1, and COMT protein expression and cell proliferation of JEG-3 and BeWo cell lines. Both mixtures induced AhR expression in JEG-3 and BeWo; however, in JEG-3 cells expression of ERα, CYP1A1, CYP1B1, and COMT was upregulated, while in BeWo cells downregulated. The opposite effect of mixtures on NFκB protein expression (inhibitory in JEG-3, stimulatory in BeWo) was noted. We suggest AhR-mediated activation of PAHs metabolism in JEG-3 cells, and AhR interaction with NFκB and AhR cross-talk with ERα causing inhibition of detoxification in BeWo cells. As a result there was a stimulatory effect on JEG-3 and an inhibitory one on BeWo cell proliferation.