ERbeta Expression Research Articles

Role of Estrogen Receptor‐α and −β in Regulating Leptin Expression in 3T3‐L1 Adipocytes

We investigated the effects of the estrogen receptor-alpha (ERalpha) and -beta (ERbeta) in the regulation of leptin, resistin, and adiponectin expression in 3T3-L1 adipocytes. Mature adipocytes were exposed to estradiol (E2), ERalpha agonist (PPT (4,4',4''-(4-propyl-[1H]-pyrazole-1,3,5-triyl)trisphenol)), ERbeta agonist (DPN (2,3-bis(4-Hydroxyphenyl)-propionitrile)), E2 with ERalpha antagonist (MPP (1,3-Bis(4-hydroxyphenyl)-4-methyl-5-[4-(2-piperidinylethoxy)phenol]-1H-pyrazole dihydrochloride)), and E2 with ERbeta antagonist (R,R-THC ((R,R)-5,11-diethyl-5,6,11,12-tetrahydro-2,8-chrysenediol)) at different concentrations. To clarify the expression and regulation of adipokines by ER subtypes, total RNA was extracted from cells and measured using quantitative PCR. Western blot analysis was performed to evaluate the protein expression of adipokines, ERalpha, and ERbeta. The leptin expression was significantly increased in the cells treated with high concentrations (10(-5) and 10(-6) mol/l) of the PPT (P < 0.01, P < 0.05). By contrast, the leptin expression decreased in a dose-dependent manner in the MPP-treated groups (P < 0.05). High concentrations (10(-5) mol/l) of R,R-THC with E2 (10(-7) mol/l) caused a significant increase of the leptin expression (P < 0.01). The leptin mRNA levels were positively correlated with the ERalpha mRNA levels (r = 0.584, P < 0.01) and negatively correlated with the ERbeta mRNA levels (r = -0.236, P = 0.03) in the adipocytes. The ratio of the ERalpha to ERbeta mRNA levels in the adipocytes was significantly associated with leptin mRNA levels (r = 0.454, P < 0.01). ERalpha induced leptin expression and ERbeta inhibited its expression in 3T3-L1 adipocytes. The ratio of the ERalpha-to-ERbeta expression in 3T3-L1 adipocytes may be an important potential regulatory factor in leptin expression.

Oestrogen Receptor α and β Immunoreactive Cells in the Suprachiasmatic Nucleus of Mice: Distribution, Sex Differences and Regulation by Gonadal Hormones

Oestrogen regulates various aspects of circadian rhythm physiology. The presence of oestrogen receptors within the suprachiasmatic nucleus (SCN), the principal circadian oscillator, indicates that some actions of oestrogen on circadian functions may be exerted at that site. The present study analysed sex differences, topographic distribution, and neurochemical phenotype of neurones expressing the alpha and beta subtypes of oestrogen receptors (ERalpha and ERbeta) in the mouse SCN. We found that relatively few neurones in the SCN are immunoreactive (IR) for ERalpha (approximately 4.5% in females and 3% in males), but five- to six-fold more SCN neurones express ERbeta. ER-IR neurones are primarily in the shell subdivision of the nucleus and show differences between the sexes, significantly greater numbers being found in females. Treatment of male or female gonadectomised mice with oestradiol benzoate for 24 h substantially reduced the number of ERbeta-IR neurones, but not ERalpha-IR neurones. Double-labelling immunocytochemical experiments to characterise the phenotype of the oestrogen-receptive neurones showed the presence of the calcium-binding proteins calretinin or calbindin D28K in approximately 12% and 10%, respectively, of ERalpha-IR neurones. A higher proportion (approximately 38%) of ERbeta-IR neurones contains calbindin D28K; a few (approximately 2%) express calretinin or vasopressin. These double-labelled cells appear primarily in the shell subdivision of the SCN. Neither vasoactive intestinal polypeptide- nor gastrin releasing peptide-immunoreactivity was observed in ER-IR neurones. These data indicate that the primary target cells for oestrogen are in the shell subdivision of the nucleus. The sexually differentiated expression and distribution of ERalpha and ERbeta in various cell populations of the SCN suggest multiple modes of oestrogen signalling within this nucleus, which may modulate circadian functions.

Soy isoflavone genistein upregulates epithelial adhesion molecule E-cadherin expression and attenuates -catenin signaling in mammary epithelial cells

Breast cancer risk is highly modifiable by diet; however, mechanisms underlying dietary protection against mammary tumorigenesis remain poorly understood. A proportion of breast carcinomas is associated with deregulation of beta-catenin stability and amplification of c-Myc expression. We recently showed that dietary exposure to the soy isoflavone genistein (Gen) inhibited Wnt transduction in rat mammary epithelial cells in vivo. Here, we explored the role of Gen on cell adhesion protein, E-cadherin, expression to downregulate beta-catenin proto-oncogene function. In mammary glands of female rats exposed to dietary Gen, E-cadherin and beta-catenin protein levels were increased, concurrent with higher beta-casein gene expression. In HC11 mouse mammary epithelial cells, Gen diminished basal and Wnt-1-induced cell proliferation and attenuated Wnt-1 targets c-Myc and Cyclin D1 expression. Whereas, Gen had no effect on E-cadherin transcript levels, the abundance of membrane E-cadherin protein and of E-cadherin-beta-catenin adhesion complex was increased by Gen, attendant with downregulation of Wnt-1-induced free beta-catenin accumulation in cytosol. Gen inhibition of Wnt-induced c-Myc expression was mimicked by an estrogen receptor (ER)-beta-specific but not ER-alpha-specific agonist and was attenuated with loss of ER-beta expression, concordant with decreased E-cadherin expression. E-cadherin small-interfering RNA targeting eliminated Gen inhibition of Wnt-stimulated c-Myc expression and promoted Gen induction of basal c-Myc transcript levels and subsequent proliferation. Our studies identify E-cadherin as a Gen cellular target and demonstrate that the dichotomy in mammary epithelial response to Gen may be a function of cellular E-cadherin expression.

The evolving role of oestrogen receptor β in clinical breast cancer

Controversy surrounds the potential clinical importance of oestrogen receptor (ER)β in breast cancer, and three recent papers have sought to resolve this. In the present issue of Breast Cancer Research Novelli and colleagues explored the significance of ERβ1 expression in 936 breast cancer patients, and they showed diverse relationships according to lymph node status. A second paper examined 442 breast cancers in which ERβ1 was an independent predictor of recurrence, disease-free survival and overall survival. Finally a third paper showed that ERβ2 was a powerful prognostic indicator in 757 breast cancers but this was dependent on cellular location, with nuclear ERβ2 expression predicting good survival whilst cytoplasmic expression predicted worse outcome. These papers point to a clinical role for ERβ in breast cancer and shall be discussed.

A divergent role for estrogen receptor-beta in node-positive and node-negative breast cancer classified according to molecular subtypes: an observational prospective study

IntroductionEstrogen receptor-alpha (ER-α) and progesterone receptor (PgR) are consolidated predictors of response to hormonal therapy (HT). In contrast, little information regarding the role of estrogen receptor-beta (ER-β) in various breast cancer risk groups treated with different therapeutic regimens is available. In particular, there are no data concerning ER-β distribution within the novel molecular breast cancer subtypes luminal A (LA) and luminal B (LB), HER2 (HS), and triple-negative (TN).MethodsWe conducted an observational prospective study using immunohistochemistry to evaluate ER-β expression in 936 breast carcinomas. Associations with conventional biopathological factors and with molecular subtypes were analyzed by multiple correspondence analysis (MCA), while univariate and multivariate Cox regression analysis and classification and regression tree analysis were applied to determine the impact of ER-β on disease-free survival in the 728 patients with complete follow-up data.ResultsER-β evenly distributes (55.5%) across the four molecular breast cancer subtypes, confirming the lack of correlation between ER-β and classical prognosticators. However, the relationships among the biopathological factors, analyzed by MCA, showed that ER-β positivity is located in the quadrant containing more aggressive phenotypes such as HER2 and TN or ER-α/PgR/Bcl2- tumors. Kaplan-Meier curves and Cox regression analysis identified ER-β as a significant discriminating factor for disease-free survival both in the node-negative LA (P = 0.02) subgroup, where it is predictive of response to HT, and in the node-positive LB (P = 0.04) group, where, in association with PgR negativity, it conveys a higher risk of relapse.ConclusionOur data indicated that, in contrast to node-negative patients, in node-positive breast cancer patients, ER-β positivity appears to be a biomarker related to a more aggressive clinical course. In this context, further investigations are necessary to better assess the role of the different ER-β isophorms.

Study on expression of estrogen receptor isoforms in eutopic and ectopic endometrium of ovarian endometriosis

To investigate the distribution of ER isoforms in endometriosis and eutopic endometrium. Tissue samples of patients with ovarian endometriosis, treated in People's Liberation Army General Hospital from January 2004 to December 2006, were retrieved. A total of 60 cases of ovarian endometriotic cysts with their corresponding eutopic endometrium (30 cases of proliferation phase and 30 of secretary phase eutopic endometrium) and 30 cases of normal endometrium (15 proliferative and 15 secretary phase endometrial samples respectively) were included. Expressions of ERalpha and ERbeta were analyzed using immunohistochemistry and the expression ratio was statistically analyzed by using SPSS 12.0 software. Expressions of both ERalpha and ERbeta in epithelial cells were positively correlated with that of the stromal cells. The expression of ERalpha in eutopic endometrium (73.3% in epithelium and 76.7% in stroma) was significantly higher than that in ovarian endometriotic cysts (43.3% in epithelium and 46.7% in stroma), or normal control (56.7% in epithelium and 50.0% in stroma, respectively, each P < 0.05. However, the expression of ERbeta (90.0% in epithelium and 76.7% in stroma) was higher in ovarian endometriotic cysts than that in the eutopic endometrium (68.0% in epithelium and 63.3% in stroma respectively, P < 0.05), and ERbeta expression in eutopic endometrium was higher than that in the normal control endometrium (36.7% in epithelium and 26.7% in stroma, respectively, P < 0.05). The expressions of both ERalpha and ERbeta changed periodically in eutopic and normal endometrium, whereas ERalpha and ERbeta level were less variable in the ectopic endometrium. The expression of ERbeta was statistically higher than that of ERalpha (P < 0.05) in ectopic endometrium, whereas no significant difference was seen between the two isoforms in the eutopic or normal endometrium. Both ERalpha and ERbeta have higher expression levels in eutopic endometrium of patients with ovarian endometriotic cysts. ERbeta is predominantly expressed in endometriotic cysts, where the expression of ERalpha is limited. The different distribution of ERalpha and ERbeta may play an important role in the development of ovarian endometriosis.

Expression of Estrogen Receptor Alpha and Beta in Breast Cancers of Pre- and Post-menopausal Women

Expression of estrogen receptors (ER) is clinically relevant in designing therapeutic strategies. The relative importance of the two types of estrogen receptors (ER-alpha and ER-beta) in human breast cancers in pre- and post-menopausal women has not been properly defined. To determine the possible association between the expression of estrogen receptor and serum estradiol levels in pre- and post-menopausal women with breast cancer. 44 patients with invasive ductal carcinoma of the breast were studied and a breast tissue biopsy was taken. ER-alpha and ER-beta were detected by immunocytochemistry. Serum levels of estradiol and estrone were measured by radioimmunoassay and FSH was measured using IRMA. We studied 21 pre- and 23 post-menopausal women with breast carcinoma. Examining the number of cases with tumors positive for ER, we found no differences in the frequency of ER-alpha between pre- and post-menopausal women, but ER-beta decreased marginally after menopause (p < 0.051). In cases with tumors positive for ER, the proportion of cells positive for ER-alpha was similar post-menopausally (53.95%) and pre-menopausally (57.21%), but for ER-beta the number of positive cells decreased significantly after menopause (p < 0.051). In pre-menopausal women there was a correlation between serum estradiol levels and ER-beta; in post-menopausal women there was a correlation between serum FSH levels and ER-alpha. These results indicate that estradiol levels in women with mammary carcinoma are related to ER-beta expression in the breast tumor tissue.

Artemisinin selectively decreases functional levels of estrogen receptor-alpha and ablates estrogen-induced proliferation in human breast cancer cells

MCF7 cells are an estrogen-responsive human breast cancer cell line that expresses both estrogen receptor (ER) alpha and ERbeta. Treatment of MCF7 cells with artemisinin, an antimalarial phytochemical from the sweet wormwood plant, effectively blocked estrogen-stimulated cell cycle progression induced by either 17beta-estradiol (E(2)), an agonist for both ERs, or by propyl pyrazole triol (PPT), a selective ERalpha agonist. Artemisinin strongly downregulated ERalpha protein and transcripts without altering expression or activity of ERbeta. Transfection of MCF7 cells with ERalpha promoter-linked luciferase reporter plasmids revealed that the artemisinin downregulation of ERalpha promoter activity accounted for the loss of ERalpha expression. Artemisinin treatment ablated the estrogenic induction of endogenous progesterone receptor (PR) transcripts by either E(2) or PPT and inhibited the estrogenic stimulation of a luciferase reporter plasmid driven by consensus estrogen response elements (EREs). Chromatin immunoprecipitation assays revealed that artemisinin significantly downregulated the level of endogeneous ERalpha bound to the PR promoter, whereas the level of bound endogeneous ERbeta was not altered. Treatment of MCF7 cells with artemisinin and the pure antiestrogen fulvestrant resulted in a cooperative reduction of ERalpha protein levels and enhanced G(1) cell cycle arrest compared with the effects of either compound alone. Our results show that artemisinin switches proliferative human breast cancer cells from expressing a high ERalpha:ERbeta ratio to a condition in which ERbeta predominates, which parallels the physiological state linked to antiproliferative events in normal mammary epithelium.

The localization and non‐genomic function of the membrane‐associated estrogen receptor in oligodendrocytes

There is general acceptance that the estrogen receptor can act as a transcription factor. However, estrogens can also bind to receptors that are located at the plasma membrane and stimulate rapid intracellular signaling processes. We recently showed that a membrane-associated estrogen receptor (mER) is present within myelin and at the oligodendrocyte (OL) plasma membrane. To understand the physiological function of mER in OLs, we investigated its cellular localization and involvement in rapid signaling in CG4 cells and OL primary cultures. An ERalpha was expressed along the lacy network of veins in the membrane sheets and in the perikaryon and nucleus in OLs. ERbeta was located in the nucleus, and to a lesser extent along the veins. The expression of ERalpha and ERbeta in OL membranes was confirmed by Western analysis of isolated membranes. OL membranes mainly had truncated forms of ERalpha, 53 and 50 kDa, in addition to some 65 kDa form, whereas ERbeta was a 54 kDa form. CG4 cells and OLs were pulsed with 17alpha- and 17beta-estradiol for various times and the total lysates were analyzed for phosphorylated kinases. Both 17alpha- and 17beta-estradiol elicited rapid phosphorylation of p42/44MAPK, Akt, and GSK-3beta within 8 min. This rapid signaling is consistent with estradiol ligation of a membrane form of ER. Since 17alpha-estradiol is produced at higher concentrations than 17beta-estradiol in the brain of both sexes, signaling via 17alpha-estradiol-liganded mER may have an important function in OLs.

Insulin resistance of pregnancy involves estrogen-induced repression of muscle GLUT4

Pregnancy is accompanied by hyperestrogenism, however, the role of estrogens in the gestational-induced insulin resistance is unknown. Skeletal muscle plays a fundamental role in this resistance, where GLUT4 regulates glucose uptake. We investigated: (1) effects of oophorectomy and estradiol (E2) on insulin sensitivity and GLUT4 expression. E2 ( approximately 200nM) for 7 days decreased sensitivity, reducing approximately 30% GLUT4 mRNA and protein (P<0.05) and plasma membrane expression in muscle; (2) the expression of ERalpha and ERbeta in L6 myotubes, showing that both coexpress in the same nucleus; (3) effects of E2 on GLUT4 in L6, showing a time- and dose-dependent response. High concentration (100nM) for 6 days reduced approximately 25% GLUT4 mRNA and protein (P<0.05). Concluding, E2 regulates GLUT4 in muscle, and at high concentrations, such as in pregnancy, reduces GLUT4 expression and, in vivo, decreases insulin sensitivity. Thus, hyperestrogenism may be involved in the pregnancy-induced insulin resistance and/or gestational diabetes.

Influence of Cellular ERα/ERβ Ratio on the ERα-Agonist Induced Proliferation of Human T47D Breast Cancer Cells

Breast cancer cells show overexpression of estrogen receptor (ER) α relative to ERβ compared to normal breast tissues. This observation has lead to the hypothesis that ERβ may modulate the proliferative effect of ERα. This study investigated how variable cellular expression ratios of the ERα and ERβ modulate the effects on cell proliferation induced by ERα or ERβ agonists, respectively. Using human osteosarcoma (U2OS) ERα or ERβ reporter cells, propyl-pyrazole-triol (PPT) was shown to be a selective ERα and diarylpropionitrile (DPN) a preferential ERβ modulator. The effects of these selective estrogen receptor modulators (SERMs) and of the model compound E2 on the proliferation of T47D human breast cancer cells with tetracycline-dependent expression of ERβ (T47D-ERβ) were characterized. E2-induced cell proliferation of cells in which ERβ expression was inhibited was similar to that of the T47D wild-type cells, whereas this E2-induced cell proliferation was no longer observed when ERβ expression in the T47D-ERβ cells was increased. In the T47D-ERβ cell line, DPN also appeared to be able to suppress cell proliferation when levels of ERβ expression were high. In the T47D-ERβ cell line, PPT was unable to suppress cell proliferation at all ratios of ERα/ERβ expression, reflecting its ability to activate only ERα and not ERβ. It is concluded that effects of estrogen-like compounds on cell proliferation are dependent on the actual ERα/ERβ expression levels in these cells or tissues and the potential of the estrogen agonists to activate ERα and/or ERβ.

Human umbilical vascular endothelial cells express estrogen receptor beta (ERβ) and progesterone receptor A (PR-A), but not ERα and PR-B

Several reports deal with possible effects of female sex hormones on human umbilical vein endothelial cells (HUVEC) including elasticity, activation of plasma membrane Na+/H+ exchange, VEGF receptor Flk-1/KDR and many others. In contrast to those findings, some publications pointed out that HUVEC lack expression of both the estrogen receptor (ER) and/or the progesterone receptor (PR). Because the majority of these investigations were carried out at a time period, when only one ER and one PR was known, the aim of this study was the systematic analysis of ERalpha and ERbeta as well as PR-A and PR-B expression in HUVEC with specific monoclonal antibodies by immunocytochemistry and quantitative RT-PCR (TaqMan). As a result, we could show that HUVEC lack ERalpha but express ERbeta. The expression of ERbeta could be significantly upregulated with 17beta-estradiol on mRNA and protein level. In addition, HUVEC express PR-A but not PR-B. PR-A expression could be significantly upregulated with progesterone, again on mRNA and protein level. We conclude that estrogenic effects on HUVEC are mediated via the ERbeta and gestagens act via the PR-A pathway.

Expression of estrogen receptor beta in the breast carcinoma of BRCA1 mutation carriers.

BackgroundBreast cancers (BC) in women carrying mutations in BRCA1 gene are more frequently estrogen receptor negative than the nonhereditary BC. Nevertheless, tamoxifen has been found to have a protective effect in preventing contralateral tumors in BRCA1 mutation carriers. The identification of the second human estrogen receptor, ERβ, raised a question of its role in hereditary breast cancer. The aim of this study was to assess the frequency of ERα, ERβ, PgR (progesterone receptor) and HER-2 expression in breast cancer patients with mutated BRCA1 gene and in the control group.MethodsThe study group consisted of 48 women with BRCA1 gene mutations confirmed by multiplex PCR assay. The patients were tested for three most common mutations of BRCA1 affecting the Polish population (5382insC, C61G, 4153delA). Immunostaining for ERα, ERβ and PgR (progesterone receptor) was performed using monoclonal antibodies against ERα, PgR (DakoCytomation), and polyclonal antibody against ERβ (Chemicon). The EnVision detection system was applied. The study population comprised a control group of 120 BC operated successively during the years 1998–99.ResultsThe results of our investigation showed that BRCA1 mutation carriers were more likely to have ERα-negative breast cancer than those in the control group. Only 14.5% of BRCA1-related cancers were ERα-positive compared with 57.5% in the control group (P < 0.0001). On the contrary, the expression of ERβ protein was observed in 42% of BRCA1-related tumors and in 55% of the control group. An interesting finding was that most hereditary cancers (75% of the whole group) were triple-negative: ERα(-)/PgR(-)/HER-2(-) but almost half of this group (44.4%) showed the expression of ERβ.ConclusionIn the case of BRCA1-associated tumors the expression of ERβ was significantly higher than the expression of ERα. This may explain the effectiveness of tamoxifen in preventing contralateral breast cancer development in BRCA1 mutation carriers.

Morphologic and Molecular Evolutionary Pathways of Low Nuclear Grade Invasive Breast Cancers and Their Putative Precursor Lesions: Further Evidence to Support the Concept of Low Nuclear Grade Breast Neoplasia Family

We have previously provided evidence showing an association between some precursor lesions with low nuclear grade breast carcinomas (LNGBCs). In this study, further immunophenotypic support to our proposed route of pathogenesis of LNGBC and their precursor lesions was provided. Precursor lesions including columnar cell lesions, atypical ductal hyperplasia, ductal carcinoma in situ, usual epithelial hyperplasia, and lobular neoplasia were compared with matching "morphologically normal" terminal lobular duct units and matching invasive carcinoma. The epithelial cells in the putative precursor flat epithelial atypia, atypical ductal hyperplasia, lobular neoplasia, ductal carcinoma in situ lesions, and their coexisting LNGBC were negative for basal and myoepithelial markers, but positive for CK19/18/8, estrogen receptor (ER)-alpha, Bcl-2, and cyclin D1. The ER-alpha/ER-beta expression ratio increased during carcinogenesis, as did expression of cyclin D1 and Bcl-2. p53 immunopositivity was found 3% in LNGBC versus 43% in high nuclear grade breast carcinoma (HNGBC), whereas ataxia telangiectasia mutated expression was absent or reduced in 22% of LNGBC versus 53% of HNGBC cases. In summary, our findings support the concept that flat epithelial atypia is the earliest morphologically identifiable nonobligate precursor lesion of LNGBC. These may represent a family of precursor, in situ and invasive neoplastic lesions belonging to the luminal "A" subclass of breast cancer. The balance between ER-alpha and ER-beta expression may be important in driving cyclin D-1 and Bcl-2 expression. Ataxia telangiectasia mutated may be one of the alternative regulatory mechanisms to TP53 mutation or dysfunction in low-grade and high-grade breast carcinoma. Our findings support the concept that progression of LNGBC to HNGBC (basal-like or HER2+) phenotype is an unlikely biologic phenomenon.

Estrogen receptor β protects against acoustic trauma in mice

The hormone estradiol affects the auditory system both by itself and by its interaction with neuroprotective factors. In this study, we examined the role of estrogen receptors (ERs) in response to auditory trauma. We found a ligand-dependent protective role for ERbeta in the auditory system by investigating mice deficient in ERalpha (ERKO mice), ERbeta (BERKO mice), and aromatase (ARKO mice). Basal auditory brainstem response (ABR) thresholds were similar in all animals. An acoustic trauma causing a temporary hearing loss raised ABR thresholds in male and female BERKO and ARKO mice compared with WT and ERKO mice. The ERalpha-selective agonist, propyl(1H) pyrazole-1,3,5-triyl-trisphenol (PPT), partially protected ARKO mice from trauma, while the ERbeta-selective agonist, 2,3-bis (4-hydroxyphenyl)-propionitrile (DPN), protected WT and ARKO mice. Immunohistochemistry and western blotting confirmed the expression of ERbeta in cochlea of WT males and females. Levels of brain-derived neurotrophic factor (BDNF), a neuroprotective peptide that can be induced by estrogen, was lower in BERKO and ARKO mice compared with WT. DPN treatment increased BDNF expression in ARKO mice. These data indicate ERbeta-mediated neuroprotection involving BDNF in the auditory system of males and females.

Estrogen Receptor β: Expression Profile and Possible Anti-Inflammatory Role in Disease

Estrogen receptor (ER) beta agonists have been demonstrated to possess anti-inflammatory properties in inflammatory disease models. The objective of this study was to determine whether ERbeta agonists affect in vitro and in vivo preclinical models of asthma. mRNA expression assays were validated in human and rodent tissue panels. These assays were then used to measure expression in human cells and our characterized rat model of allergic asthma. ERB-041 [7-ethenyl-2-(3-fluoro-4-hydroxyphenyl)-1,3-benzoxazol-5-ol], an ERbeta agonist, was profiled on cytokine release from interleukin-1beta-stimulated human airway smooth muscle (HASM) cells and in the rodent asthma model. Although ERbeta expression was demonstrated at the gene and protein level in HASM cells, the agonist failed to have an impact on the inflammatory response. Similarly, in vivo, we observed temporal modulation of ERbeta expression after antigen challenge. However, the agonist failed to have an impact on the model endpoints such as airway inflammation, even though plasma levels reflected linear compound exposure and was associated with an increase in receptor activation after drug administration. In these modeling systems of airway inflammation, an ERbeta agonist was ineffective. Although ERbeta agonists are anti-inflammatory in certain models, this novel study would suggest that they would not be clinically useful in the treatment of asthma.

Hormone Receptor Expression in Renal Angiomyolipoma: Clinicopathologic Correlation

Although renal angiomyolipoma (AML) occurs more commonly in females than males, the origin of this difference in incidence by sex is unknown. Therefore, we investigated the expression of the androgen receptor (AR), estrogen receptor subtypes alpha (ERalpha) and beta (ERbeta), progesterone receptor, and the enzyme aromatase in renal AML. We evaluated specimens from 110 patients who had undergone resection of a renal AML, including 90 women and 20 men. Immunohistochemistry was performed using monoclonal antibodies on paraffin-embedded tissue sections. Expression was correlated with patient demographics and tumor pathologic features. ERbeta was expressed in 100% (106 of 106) of the AML specimens evaluated. Of the 104 specimens that could be assessed for the AR, 82 (79%) demonstrated staining. Of 110 lesions, 31 (28%), 42 (38%), and 11 (10%) expressed ERalpha, progesterone receptor, and aromatase, respectively. The level of ERbeta expression was not associated with patient age (P = 0.92), sex (P = 0.82), a diagnosis of tuberous sclerosis (P = 0.56), or histologic subtype of AML (P = 0.94). A trend was found toward increased AR expression in men (P = 0.069) and younger patients (P = 0.052), and ERalpha was expressed in the AML specimens from 5 (71%) of 7 patients with tuberous sclerosis compared with 26 (25%) of 103 without tuberous sclerosis (P = 0.018). Both AR and ERalpha expression were more common in the triphasic subtype of AML than in the lipomatous tumors (P = 0.046 for both). The results of our study have shown that ERbeta expression is ubiquitous in renal AML, and the AR is found in most tumors. ERalpha and progesterone receptor were expressed in approximately one third of cases. These data suggest a potential role for hormones in the pathogenesis and management of renal AML.

Expression and regulation of oestrogen receptors in the human corpus luteum

The molecular mechanisms underlying the control of corpus luteum lifespan in women are not fully understood. Oestradiol has various luteolytic, or luteotrophic, functions in some species, and as it is synthesised within the human corpus luteum, it is an excellent candidate molecule to be a paracrine regulator of luteal function. This study aimed to comprehensively investigate the expression, regulation and effects of oestrogen receptors (ER) in human luteal cells. Genomic oestrogen receptors ERalpha, ERbeta1 and ERbeta2 were immunolocalised in human corpora lutea from throughout the luteal phase. mRNA expression was investigated throughout the luteal phase and after luteal rescue with exogenous human chorionic gonadotrophin (hCG). The regulation of ER expression and oestradiol action was investigated in cultures of luteinised granulosa cells. ER subtypes ERbeta1 and ERbeta2 were localised throughout the luteal phase to steroidogenic cells in the human corpus luteum and cells of the surrounding stroma. Unlike follicular granulosa cells, steroidogenic cells in the corpus luteum showed minimal ERalpha immunostaining. The presence of endothelial cells in the granulosa cell layer with ERbeta1 and ERbeta2 positive nuclei was noted. ERbeta1 and ERbeta2 were differentially regulated across the luteal phase with ERbeta1 maximally expressed in the mid-luteal phase, while ERbeta2 expression was maximal in the early luteal phase. In vivo and in vitro, hCG had no long-term effect on ER expression, although in vitro hCG and oestradiol acutely down-regulated ERs. Treatment with oestradiol in vitro down-regulated 11beta-hydroxysteroid dehydrogenase type 1 and inhibin betaA subunit confirming a functional oestradiol response. These data highlight functional and differentially regulated oestradiol reception in human luteal cells.

Cloning of gene fragment of estrogen receptor-βand its expression in mouse embryo

In order to study the expression and regulation effects of estrogen receptor-beta (ERbeta) in the development of mouse embryo, the primer of ERbeta was designed, the ERbeta fragment was first obtained by RT-PCR and subcloned into plasmids pGEM- 3Z, then the recombinant plasmids were linearized with the restriction enzymes of EcoRand Hind. Using Sp6 and T7 RNA polymerase, the digoxigenin(dig) labeled sense and anti-sense probes were transcriped in vitro, respectively. Then the expression of ERbeta in mouse embryo was examined with the probes by whole-mount in situ hybridization. The results indicated that ERbeta is expressed in the brain, spinal neural tube, genital ridge, pericardium, limb bud and mandibular arch of 10.5 dpc embryo, and is also expressed in the telencephalon, mesencephalon, medulla oblongata, spinal cord and limb bud of 13.5 dpc embryo. These results suggest that ERbeta maybe play a role of regulation in sexual differentiation, primal differentiation of neural tube, further differentiation of three primary cerebral vesicles and spinal cord, generation and differentiation of bone and cartilage of limb bud, development of pericardium and configuration differentiation of mandibular in mouse embryo.

Effects of testosterone and estrogen treatment on the distribution of sex hormone receptors in the endometrium of postmenopausal women

Our aim was to investigate the effects of the addition of testosterone to estrogen compared with those of estrogen alone on the expression and distribution of sex hormone receptors in glands and stroma of the endometrium of postmenopausal women. An open, randomized clinical study with parallel group comparison was performed in the Women's Health Research Unit at a university hospital. Thirty-one postmenopausal women were given oral estradiol valerate (2 mg daily) or estradiol valerate in combination with testosterone undecanoate (40 mg every 2 days) for 3 months. Before and at the end of treatment, endometrial biopsy samples were obtained, and expressions of estrogen receptor (ER)-alpha, ER-beta, progesterone receptor isoforms A and B, and androgen receptor (AR) were evaluated by immunohistochemical analysis. At baseline, expressions of ER-alpha and progesterone receptors were stronger in glands than in stroma, whereas the immunostaining of AR was stronger in stroma than in glands. After treatment, expressions of ER-alpha and progesterone receptors were up-regulated in both glands and stroma by both treatments, but to a lesser extent in glands by combined treatment. The expression of ER-beta in glands was significantly higher with combined treatment than with estrogen alone. Moreover, AR immunostaining was significantly higher after combined treatment than after treatment with estrogen alone. Expressions of AR and ER-beta were stronger in glands of the endometrium of postmenopausal women after treatment with testosterone added to estrogen than after estrogen alone. In contrast, expressions of ER-alpha and progesterone receptors were up-regulated in the endometrium with estrogen-alone treatment, whereas these expressions were less increased in glands after combined treatment. These data indicate that testosterone is involved in the regulation of sex hormone receptor expression in the postmenopausal endometrium and may therefore influence endometrial proliferation and differentiation.