Role Of Estrogen Receptor Beta Research Articles

Abstract 3465: p53 status as a determinant of estrogen receptor beta function in breast cancer

Abstract While the importance of estrogen receptor alpha (ERα) in breast cancer is well documented, role of estrogen receptor beta (ERβ) still remains elusive. Whether ERβ is an oncogenic or a tumor suppressor protein in breast cancer remains controversial. ERβ levels are high in ERα negative cancers including triple-negative breast cancer (TNBCs). Recent reports including the Cancer Genome Atlas (TCGA) show that about 80% of TNBC express mutant p53 (mut-p53) and it is the most predominant driver mutant in these cancers. Importantly, in addition to losing tumor suppressor activity, mut-p53 gains oncogenic functions, and therefore, has a major role in driving the cancer process. We tested the hypothesis that p53 status in breast cancer will have an important role in determining function of ERβ. We report that ERβ directly binds to p53 in human breast cancer cells. Using glutathione-S-transferase (GST)-pull down and co-imunoprecipitation assays, we have delineated the domains of both proteins that are required for the ERβ-p53 interaction. The DNA binding domain (DBD) along with the hinge domain of ERβ and the C-terminal regulatory domain of p53 are essential for the interaction. Using the highly sensitive proximity ligation assay (PLA), we show ERβ-p53 interaction in situ in breast cancer cells expressing either wt- or mut-p53. Surprisingly, we found that ERβ has opposite functions depending on the wt/mut status of p53. A combination of proliferation and apoptosis assays, RNAi technology, quantitative chromatin immunoprecipitation (qChIP), and quantitative real-time PCR (qRT-PCR) showed that in the context of the wt-p53, ERβ is pro-proliferative, whereas in the context of mut-p53, ERβ is anti-proliferative. ERβ binds wt-p53 and inhibits its transcriptional function. On the other hand, ERβ binds and sequesters mut-p53 from mut-p53−p73 complex leading to reactivation of tumor suppressor p73. Consistent with findings in cell culture models, combination of immunohistochemistry (IHC) and PLA in TNBC patient tissue microarray (TMA) representing 130 tumors followed by correlative analysis of linked patient tumor characteristics obtained from RPCI clinical data network showed that p53 status is an important determinant of ERβ function. For example, ERβ along with mut-p53 has negative effect on tumor growth, whereas ERβ in the wt-p53 context has opposite effect. Our finding that ERβ elicits opposite functions dependent on p53 status provides an important insight into the mechanism underlying the context-dependent function of ERβ and provides an explanation to the controversial reports on pro- versus anti-tumorigenic role of ERβ. These data would have significant clinical implications in targeting ERβ and mutant p53 signaling pathways for diagnostic, prognostic, and therapeutic purposes especially in ERα negative cancers such as triple negative breast cancer. Note: This abstract was not presented at the meeting. Citation Format: Gokul M. Das, Utpal K. Mukhopadhyay, Sanjay Bansal, Nadi Wickramasekera, Rajesh Medisetty, Wendy M. Swetzig, Austin Miller, Jianmin Wang, Chetan Oturkar, Alka Mukhopadhyay, Santhi Konduri. p53 status as a determinant of estrogen receptor beta function in breast cancer. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 3465. doi:10.1158/1538-7445.AM2015-3465

Estrogen receptor beta in prostate cancer: friend or foe?

Prostate cancer is the commonest, non-cutaneous cancer in men. At present, there is no cure for the advanced, castration-resistant form of the disease. Estrogen has been shown to be important in prostate carcinogenesis, with evidence resulting from epidemiological, cancer cell line, human tissue and animal studies. The prostate expresses both estrogen receptor alpha (ERA) and estrogen receptor beta (ERB). Most evidence suggests that ERA mediates the harmful effects of estrogen in the prostate, whereas ERB is tumour suppressive, but trials of ERB-selective agents have not translated into improved clinical outcomes. The role of ERB in the prostate remains unclear and there is increasing evidence that isoforms of ERB may be oncogenic. Detailed study of ERB and ERB isoforms in the prostate is required to establish their cell-specific roles, in order to determine if therapies can be directed towards ERB-dependent pathways. In this review, we summarise evidence on the role of ERB in prostate cancer and highlight areas for future research.

Estrogen receptor alpha/beta ratio and estrogen receptor beta as predictors of endocrine therapy responsiveness–a randomized neoadjuvant trial comparison between anastrozole and tamoxifen for the treatment of postmenopausal breast cancer

BackgroundThe role of estrogen receptor beta (ER-β) in breast cancer (BC) remains unclear. Some studies have suggested that ER-β may oppose the actions of estrogen receptor alpha (ER-α), and clinical evidence has indicated that the loss of ER-β expression is associated with a poor prognosis and resistance to endocrine therapy. The objective of the present study was to determine the role of ER-β and the ER-α/ER-β ratio in predicting the response to endocrine therapy and whether different regimens have any effect on ER-β expression levels.MethodsNinety postmenopausal patients with primary BC were recruited for a short-term double-blinded randomized prospective controlled study. To determine tumor cell proliferation, we measured the expression of Ki67 in tumor biopsy samples taken before and after 26 days of treatment with anastrozole 1 mg/day (N = 25), tamoxifen 20 mg/day (N = 24) or placebo (N = 29) of 78 participants. The pre- and post-samples were placed in tissue microarray blocks and submitted for immunohistochemical assay. Biomarker statuses (ER-β, ER-α and Ki67) were obtained by comparing each immunohistochemical evaluation of the pre- and post-surgery samples using the semi-quantitative Allred’s method. Statistical analyses were performed using an ANOVA and Spearman’s correlation coefficient tests, with significance at p ≤ 0.05.ResultsThe frequency of ER-β expression did not change after treatment (p = 0.33). There were no significant changes in Ki67 levels in ER-β-negative cases (p = 0.45), but in the ER-β-positive cases, the anastrozole (p = 0.01) and tamoxifen groups (p = 0.04) presented a significant reduction in post-treatment Ki67 scores. There was a weak but positive correlation between the ER-α and ER-β expression levels. Only patients with an ER-α/ER-β expression ratio between 1 and 1.5 demonstrated significant differences in Ki67 levels after treatment with anastrozole (p = 0.005) and tamoxifen (p = 0.026).ConclusionsOur results provide additional data that indicate that the measurement of ER-β in BC patients may help predict tamoxifen and anastrozole responsiveness in the neoadjuvant setting. These effects of hormonal treatment appear to be dependent on the ratio of ER-α/ER-β expression.Trial registrationCurrent Controlled Trials ISRCTN89801719

Correction: Potential Role of Estrogen Receptor Beta as a Tumor Suppressor of Epithelial Ovarian Cancer

There was an error in the Funding statement. The correct statement is: This work was supported by grants from ARC (Association pour la Recherche contre le Cancer, Grant No. 3582) (http://www.arc-cancer.net), The Ligue Nationale Contre le Cancer (http://www.ligue-cancer.net). Muriel Busson was supported by FRM (Fondation pour la Recherche Medicale) (http://www.frm.org). DV was a recipient of the Ligue Nationale contre le Cancer. CB was supported by a HFSP fellowship (http://www.hfsp.org/). The K. B. lab is supported by the Agence Nationale de la Recherche (ANR, grant number 2010 JCJC 1104 01) (http://www.agence-nationale-recherche.fr ​/), the Universite Paris-Sud, the Institut National de la Sante et de la Recherche Medicale (INSERM) and the Ligue Nationale Contre le Cancer (Comite Val d'Oise), and is a member of the Laboratory of Excellence LERMIT (Laboratory of Excellence in Research on Medication and Innovative Therapeutics) supported by a grant from ANR (Investissements d´Avenir). Dr Madly Brigitte was supported by the Fondation ARC and Dr Carine Jacquard by INCA (Institut National du Cancer). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

Given breast cancer, is fat better than thin? Impact of the estrogen receptor beta gene polymorphisms

The role of estrogen receptor beta (ERβ) in breast cancer has been investigated since its identification in 1996. Studies based on protein expression have indicated that ERβ is a favorable prognostic marker. Further, ERβ expression is lower in obese breast cancer patients. Fewer studies have focused on the prognostic impact of ERβ polymorphisms. Therefore, we analyzed the associations between four previously identified haplotype tagging single nucleotide polymorphisms (htSNPs), associated haplo- and diplotypes, and breast cancer-free survival according to body constitution. The patient cohort included 634 women from the prospective breast cancer and blood study (BC Blood study, Sweden) with a median follow-up of 4.92years. Four htSNPs (i.e., rs4986938, rs1256049, rs1256031, rs3020450) in the ESR2 gene and the correlating haplo- and diplotypes were analyzed and correlated to selected patient and tumor characteristics and to disease-free survival, including stratification for BMI. Based on the four htSNPs, seven haplotypes and eight diplotypes were identified. The patient and tumor characteristics were well-balanced across all geno- and haplotypes. Disease-free survival differed according to rs4986938 and rs1256031 (Log-Rank P=0.045 and P=0.041, respectively) and the number of haplotype copies of the wildtype CCGC and TCAC (Log-Rank P=0.027 and P=0.038, respectively). In the survival analyses stratified for BMI, significant survival differences between alleles were observed among overweight women (rs4986938 and rs1256031 with Log-Rank P=0.001 and P=0.001, respectively). The BMI-stratified survival analyses based on haplotypes showed shorter disease-free survival for overweight women with null copies of CCGC (Log-Rank P=0.001) and for overweight women with any TCAC copy (Log-Rank P<0.0001). Markedly impaired disease-free survival was found for genotypes in two out of four ESR2 htSNPs and for two haplotypes. ESR2 polymorphisms seem to divide patients into good and poor survivors based on BMI, stressing the need of taking host factors into consideration in the evaluation of prognostic markers.

Potential Role of Estrogen Receptor Beta as a Tumor Suppressor of Epithelial Ovarian Cancer

Ovarian cancer is the gynecological cancer exhibiting the highest morbidity and improvement of treatments is still required. Previous studies have shown that Estrogen-receptor beta (ERβ) levels decreased along with ovarian carcinogenesis. Here, we present evidence that reintroduction of ERβ in BG-1 epithelial ovarian cancer cells, which express ERα, leads in vitro to a decrease of basal and estradiol-promoted cell proliferation. ERβ reduced the frequency of cells in S phase and increased the one of cells in G2/M phase. At the molecular level, we found that ERβ downregulated total retinoblastoma (Rb), phosphorylated Rb and phospho-AKT cellular content as well as cyclins D1 and A2. In addition, ERβ had a direct effect on ERα, by strongly inhibiting its expression and activity, which could explain part of the anti-proliferative action of ERβ. By developing a novel preclinical model of ovarian cancer based on a luminescent orthotopic xenograft in athymic Nude mice, we further revealed that ERβ expression reduces tumor growth and the presence of tumor cells in sites of metastasis, hence resulting in improved survival of mice. Altogether, these findings unveil a potential tumor-suppressor role of ERβ in ovarian carcinogenesis, which could be of potential clinical relevance for the selection of the most appropriate treatment for patients.

Investigation of immunohistochemical ERα, ERβ and ERβcx expressions in normal and neoplastic breast tissues

Estrogen receptor alpha (ERα) is a well-established prognostic marker in breast cancer. The role of estrogen receptor beta (ERβ) in breast cancers is still under investigation. We aimed to investigate the clinicopathological significance and immunohistochemical expression patterns of ERα, total ERβ (ERβ) and its spliced variant ERβcx in normal breast, ductal carcinoma in situ (DCIS) and invasive ductal carcinoma (IDC).Our study population comprised 10 normal breasts, 26 DCISs and 44 IDCs. Immunohistochemical expression of these markers was investigated in sections of formalin-fixed, paraffin-embedded blocks by 2 observers.In invasive ductal carcinomas, ERβ expression had a significant positive correlation with ERα expression (p=0.013), while ERβcx expression was significantly associated with the presence of lymphovascular invasion (p=0.046). There was a significant relationship between ERα expression and low histological grade (p<0.0001). Similarly, ERα+/ERβ+ tumors (p=0.004) and ERα+/ERβcx+ tumors (p=0.008) were significantly associated with low histological grade, too. ERα expression (p=0.009), ERβcx expression (p=0.048) and ERα+/ERβ+ coexpression (p=0.002) increased significantly in progression from normal breast to invasive ductal carcinoma.Expression of ERα correlates with less aggressive phenotypic features, and ERβ expression is positively correlated with ERα expression in breast cancer. ERβcx is associated with aggressive features and can take part in the progression of invasive carcinoma. Increase in ERα+/ERβ+ coexpression, ERα expression and ERβcx expression in breast cancer progression indicates an enhancement in ER expressions or an alteration in expression patterns of different ER variants during mammary carcinogenesis.

Differential role of estrogen receptor beta in early versus metastatic non-small cell lung cancer.

Although women have an increased susceptibility to lung cancer, they also have a favorable clinical outcome. This may in part be due to female specific genetic and hormonal factors. In the present study, expression of ER-beta was investigated by immunohistochemistry using tissue samples from two cohorts: non-small cell lung cancer (NSCLC) diagnosed in 1999 in Manitoba and advanced NSCLC patients from the NCIC-CTG BR.18 trial. In the Manitoba cohort assessable tissue samples available in 79 patients (32 females and 47 males) and the majority (75%) had early stage disease. Fifty-one percent of patients expressed high levels of ER-beta (defined by ≥60, the median immunohistochemistry score) and its expression was comparable in males and females. The 3-year overall survival of the group was 53% and males had significantly worse survival compared to females (HR=2.37, 95%CI 1.15–4.91, P=0.02). Higher ER-beta 1 expression was associated with better survival in both univariate (HR=0.41, 95%CI 0.21–0.80, P=0.009) and in multivariate (HR=0.37, 95%CI 0.18–0.77, P=0.008) analysis. In the NCIC-CTG cohort that were more often later stage, assessable tissue samples from 48 cases were available however higher ER beta 1 expression correlated with poorer survival (HR= 1.94, 95%CI 1.01–3.75 P=0.047). These results suggest a differential impact of ER-beta 1 expression on clinical outcome by disease stage, that needs to be explored further and may explain contradictory observations reported in the literature.

Abstract 5590: Role of estrogen receptor-beta in colitis-associated cancer

Abstract Inflammatory bowel disease has been strongly correlated with colitis-associated cancer (CAC) cases, a subtype of colorectal cancer. Previously, we demonstrated that estrogen receptor-beta (ERβ) exerted protective effects against the development of colonic precancerous lesions in the azoxymethane-induced spontaneous colon cancer in vivo model. In the present study, we investigated whether ERβ could also be protective against CAC. Estrogen receptor-β knockout (βERKO) and wild type (WT) mice were exposed to azoxymethane, followed by dextran sodium sulfate (DSS) treatment. Three days after the DSS treatment two βERKO mice died, suggesting that these mice might be more susceptible to inflammatory inducers than WT mice. Furthermore, six weeks after DSS exposure five mice from each group were sacrificed and morphology and RNA analyses of inflammation markers were performed. All βERKO mice presented polyp-like structures in the colon (3.60 ± 0.81) and greater number of cellular infiltration areas (9.00 ± 1.50), whereas only two WT mice presented polyp-like structures (2.40 ± 1.47) and fewer number of cellular infiltration areas (4.00 ± 2.02). βERKO mice showed 9.8 and 5.6 fold increase in mRNA expression of inducible-nitric oxide synthase (iNOS) and tumor necrosis factor-alpha (TNF-α), respectively, when compared to WT mice. In both βERKO and WT mice a 2.1 fold increase in cyclooxygenase-2 (COX-2) mRNA expression was observed compared to the respective negative control groups. All together these results suggest that ERβ might be protective against CAC. These data will be compared to the group of mice that will be sacrificed 15 weeks post DSS treatment. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 5590. doi:10.1158/1538-7445.AM2011-5590

Abstract P2-06-07: Estrogen Receptor Beta as a Coadjuvant Target? A Short-Time Prospective Double Blind Study

Abstract Background: The role of estrogen receptor beta (ER-b) in human breast cancer remains unclear. There is no consensus regarding the clinical utility of an ER-b assay. Some studies have suggested that ER-b may oppose actions of estrogen receptor alpha (ER-a) in breast cancer cells and clinical evidences indicate that loss of ER-b expression is associated with a poor prognosis and resistance to endocrine therapy. Tumor expression of the Ki67 antigen is used to assess the prognosis of cancer patients. A change in the expression of Ki67 after short-term exposure of patients to therapeutic agents is frequently used as a proliferation marker of treatment efficacy. The association between ER-b and HER-2, the human epidermal growth factor receptor 2 used in the clinical setting as a prognostic and predictive marker, in breast tumors remains unclear. Objectives: The aim of this study was to compare the expression of Ki-67, HER-2, ER-a and ER-b in postmenopausal women with invasive ductal carcinomas (IDC), prior and after tamoxifen and anastrozole in neoadjuvant short-time treatment. Material and Methods: Patients were double-blind randomized in a prospective placebo controlled study with three neoadjuvant hormone therapy (HT) groups. To determine the clinical significance of the tumor cell proliferation during endocrine therapy for breast cancer, we measured the expression of Ki67 in tumor biopsy samples taken before and after 26 days of presurgical treatment with anastrozole 1mg/day (n= 25) or tamoxifen 20mg/day (n= 24) or placebo (n=29) in 78 patients with primary palpable IDC (stage II and III). Pre and post HT samples were disposed in tissue micro array blocks and submitted to immunohistochemical essay. Biomarkers status (Ki-67, HER-2, ER-a and ER-b) were obtained comparing each immunohistochemical evaluation of pre and post-surgery samples using semi-quantitative Allred's method. Statistical analysis were performed using the GEE (General Estimation Equations) and Anova tests with significant p &amp;lt; 0,05. Results: Randomization was adequate. HER2 did not show any variation in the three groups evaluated. With positive ER-b (Allred's score 3 to 8), only anastrozole group showed a significant reduction in KI-67 status from 4.46 in the pre-treatment to 3.15 in post treatment samples (p=0.0130). Positive ER-a breast cancers showed a significant reduction in KI-67 status in tamoxifen and anastrozole groups, and this reduction was correlated to a positive ER-b score. Discussion: Clinical management of breast cancer is guided by assessment of some tumor parameters. One of these is estrogen receptor status. With the discovery of ER-b, definition of ER status is potentially more complex. Our study brings new data about the short-time exposure to endocrine therapy. The role of ER-a may be different when co-expressed with ER-b and ER-b signaling may be a therapeutic target in these tumors. Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P2-06-07.

Estrogen receptor β causes a G2 cell cycle arrest by inhibiting CDK1 activity through the regulation of cyclin B1, GADD45A, and BTG2

The role of estrogen receptor beta (ERβ) in breast cancer is unclear. ERβ is considered to have a protective role in breast cancer development based on findings demonstrating that ERβ expression inhibits ERα-mediated proliferation of breast cancer cells. We previously demonstrated that ERβ causes a ligand independent G2 cell cycle arrest in MCF-7 cells. To study the mechanisms of the ERβ-mediated G2 cell cycle arrest, we investigated its effects on the regulatory pathways responsible for the G2/M phase transition. We found that ERβ inhibits CDK1 activity, which is the critical determinant of the G2/M progression. CDK1 activity is modulated by both stimulatory and inhibitory factors. Cyclin B1 is the major activator of CDK1. ERβ inhibited the cell cycle-dependent stimulation of cyclin B1 mRNA and protein. GADD45A and BTG2 are two major inhibitors of CDK1, which have been implicated in breast tumor formation. Based on these findings, we explored if the expression pattern of GADD45A and BTG2 is affected by ERβ. We found that ERβ stimulates GADD45A and BTG2 mRNA levels. The induction of these two genes is caused by ERβ binding directly to these genes and recruiting c-jun and NCOA2. Our findings demonstrated that unliganded ERβ causes a G2 cell cycle arrest by inactivating CDK1 through the repression of cyclin B1 and stimulation of GADD45A and BTG2 expression. These results provide evidence that drugs that stimulate the production of unliganded ERβ may be effective new therapies to prevent breast cancer.

Endometrial expression of estrogen receptor β and its splice variants in patients with and without endometriosis

The role of estrogen receptor beta (ERβ) in pathogenesis of endometriosis remains to be elucidated. In this study, we have examined the expression of the four main ERβ transcript isoforms in human endometrial tissue in women with or without endometriosis. Total RNA was isolated from native endometrial tissue and transcript levels of ERα, β1, β2, β4, β5 were analyzed by means of RT-PCR. We compared the results with regard to menstrual cycle phase as well as to presence or absence of endometriosis. We prospectively harvested the endometrium of ten women without endometriosis (five for each cycle phase) and eight patients with endometriosis (five in the proliferative phase, three in the secretory phase). ERα, β1, β2, and β5 transcripts were detected in both cycle phases. During the proliferative phase, healthy women had a significantly higher ERα/ERβ1-ratio than patients with endometriosis. Irrespective of the cycle phase, ERα-mRNA level was significantly higher than transcript levels of ERβ isoforms. ERα, β1, β2, and β5 are expressed in human endometrium. The individual receptors differed in terms of expression strength but there was no relevant change during the cycle. The decreased ERα/ERβ1-ratio in proliferative endometrium of endometriosis patients suggest that ERβ1 might be involved in the pathogenesis of endometriosis. Further studies should be undertaken to substantiate the role of ERβ in endometrial pathology.

Estrogen receptor beta participate in the regulation of metabolizm of extracellular matrix in estrogen alpha negative breast cancer.

The biology of breast cancer is closely releted to sex steroid hormones. Estrogen receptor beta is overexpressed in around 70% breast cancer cases, referrd to as "ER positive". Estrogens bind to estrogen receptor and stimulate the transcription of genes involved in control of cell proliferation. Moreover, estrogens may induce growth factors and components of extracellular matrix and interact with them in a complex manner. Extracellular matrix and integrins play an important role in cell functions and their aberrant expressions are implicated in breast cancer development, invasion and metastasis. ER beta is certainly associated with more differentiated tumors, while evidence of role of ER beta is controversial. The highly invasive breast cancer ER beta negative cell line MDA-MB 231 can be the model of exam the role of ER beta in breast cancer. The aim of this study was to examine the role of activation of ER beta on the metabolism of the extracellular matrix and the expression of beta-1 integrin in the breast cancer cell line MDA-MB 231. The cells were exposed on the estradiol, tamoxifen, raloxifen and genisteina in dose dependent concentrations. To determine the relative rate of collagen syntesis we measured the time-dependent reduction of collagen-bound radioactivity after pulse-chase labeling with [3 H] prolina by Peterkofsky methods. The expression of beta-1 integrin was determine by Western blot analysis. The activity of MMP2 and 9 were measured using gelatin zymography with an image analysis system. Our data suggest on the role of estrogen receptor beta on the metabolism of extracellular matrix in the breast cancer line MDA - MB 231. Estradiol and SERMs regulate the expression of ECM proteins: collagen, integrins and enhance activity of metaloproteinases 2 and 9.

Genetic mapping of Mom5 , a novel modifier of Apc Min -induced intestinal tumorigenesis

The initial purpose of this study was to assess the role of estrogen receptor beta (ERbeta) in intestinal tumorigenesis by examining the effects of an ERbeta knockout (ERbeta(-/-)) on Apc(Min) mice. In order to accomplish this goal on a uniform genetic background, we were required to backcross the ERbeta knockout from the 129P2 genetic background to the B6 genetic background for 10 generations. Midway through this process, we performed a test cross in which mice from the N(5) backcross generation of the ERbeta knockout strain were intercrossed with Apc(Min/+) mice to obtain Apc(Min/+) ERbeta(+/+), Apc(Min/+) ERbeta(+/-) and Apc(Min/+) ERbeta(-/-) mice. Intestinal tumorigenesis in the N(5)F(2) mice was evaluated at 14 weeks of age. The analysis of the impact of ERbeta in the N(5) cross was complicated by segregating 129P2-derived alleles that affected tumor number and were unlinked to ERbeta. Genetic linkage analysis of this cross permitted the localization of a single genetic modifier of tumor number in Apc(Min/+) mice. This locus, Modifier of Min 5 (Mom5), maps to proximal mouse chromosome 5; the 129P2 allele of this locus is associated with a 50% reduction in mean intestinal tumor number. Through in silico analysis and confirmatory sequencing, we have identified the Rad50-interacting protein-1 gene as a strong candidate for Mom5.

Tissue microarray analysis of hormonal signaling pathways in uterine carcinosarcoma

To evaluate the relationship of hormone (estrogen receptor alpha, estrogen receptor beta, progesterone receptor) and growth factor receptor (insulin-like growth factor receptor, human epidermal growth factor receptor 2) expression with disease progression in uterine carcinosarcoma. Immunohistochemistry was performed on tissue arrays using standard methodology. Differences between groups were evaluated by the Wilcoxon rank-sum test. Interactions between tumor stage and receptor expression were determined by linear trend analysis. Compared with normal endometrium, carcinosarcomas exhibited low estrogen receptor alpha and progesterone receptor expression (all P < .01), but overexpressed estrogen receptor beta (P = .02). Estrogen receptor beta expression increased in advanced stage disease (P = .02). Insulin-like growth factor receptor expression was lower in carcinosarcoma compared with normal endometrium (P = .01). Human epidermal growth factor receptor 2 expression was elevated and increased with disease progression (P < .01). In uterine carcinosarcoma, estrogen receptor beta expression is elevated and increases with disease progression, whereas estrogen receptor alpha and progesterone receptor are suppressed. Human epidermal growth factor receptor 2 expression is increased, whereas insulin-like growth factor receptor is lower than in normal endometrium. These data support a potential role for estrogen receptor beta in disease progression via crosstalk with human epidermal growth factor receptor 2.

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.

Different estrogen receptor β expression in distinct histologic subtypes of lung adenocarcinoma

Adenocarcinoma is becoming the most common histologic type of lung cancer in both sex. Although most cases are seen in smokers, it develops more frequently than other histologic types in individuals who have never smoked. This evidence suggests that other putative etiologic factors, such as sex hormones, need to be investigated. Several subtypes of lung adenocarcinoma have been recently described with distinct clinicopathologic features and prognostic implications. The purpose of this study is to investigate the role of estrogen receptor beta in lung adenocarcinoma, with particular attention paid to its different histologic subtypes. Nuclear estrogen receptor beta expression was evaluated by immunohistochemistry in 112 lung adenocarcinomas, including both "single subtype" and "mixed subtype" samples. Using a 2-level (high/low) score system, estrogen receptor beta expression was high in most (75%) adenocarcinomas and turned out to be strongly related to the histologic subtypes. In fact, estrogen receptor beta expression was low or negative in 68.2% of solid subtypes, whereas it was high in 76.5% of nonmucinous bronchioloalveolar, in 69.4% of acinar, and in 61.2% of papillary patterns (P = .00004). Furthermore, a strong association between estrogen receptor beta expression and tumor histologic grade was observed: estrogen receptor beta was highly expressed predominantly in well- and moderately differentiated tumors (P = .0014). In conclusion, estrogen receptor beta expression has distinct patterns in lung adenocarcinoma, suggesting a specific role for estrogen receptor beta in the pathogenesis of different histologic subtypes of this type of cancer. Moreover, loss of estrogen receptor beta expression in poorly differentiated (G3) tumors could represent a crucial step in the dedifferentiation process of lung adenocarcinoma.

Estrogen Receptor-Beta Regulates Mechanical Signaling in Primary Osteoblasts

Mice lacking estrogen receptor-alpha (ERα) show reduced periosteal bone formation in response to mechanical loading suggesting that ERa plays an important role in bone mechanotransduction. Much less is known about the role of estrogen receptor-beta (ERβ) in mechanotransduction. Recent studies in female mice lacking ERβ show they have an enhanced response to mechanical loading suggesting that ERβ may inhibit load-induced periosteal bone formation. The enhanced response to loading is not observed in male mice lacking ERβ. PURPOSE: To determine the role of ERβ in osteoblast mechanotransduction in the presence and absence of estradiol. METHODS: Primary calvarial osteoblasts were harvested from 3–5 day-old wild-type (WT) and estrogen receptor-beta knockout (ERβ-−/−) mice and cultured in Dulbecco's minimum essential media (DMEM) + 10% fetal calf serum (FCS) and 1 % penicillin/ streptomycin (P/S). Early passage WT and ERβ−/− cells were plated onto collagen-coated glass slides. At 80% confluency, cells were loaded into parallel plate flow chambers and subjected to oscillatory fluid flow (OFF) which produced a fluid shear stress of 15 dyn/cm2 at 1 Hz. Cells were subjected to OFF for varying periods in the presence and absence of estradiol, and the activation of mechanical signaling pathways known to be important in bone physiology was observed. RESULTS: OFF significantly enhanced prostaglandin E2 (PGE2) release in WT and ERβ−/− cells in both the presence and absence of estradiol. PGE2 levels were significantly higher in ERβ−/− cells subjected to OFF and treated with estradiol compared to all other groups. Cyclooxygenase 2 (COX-2) expression was significantly greater in WT, but not ERβ−/− cells, in the absence of estradiol. Estradiol treatment rescued OFF-induced COX-2 expression in ERβ−/− cells. Estrogen receptor transcriptional activity, as measured by estrogen responsive element (ERE)-luciferase reporter activity, was significantly greater in ERβ-−/− cells regardless of flow conditions. OFF significantly enhanced transcriptional activity in ERβ−/− cells treated with estradiol. CONCLUSIONS: ERβ may normally suppress load-induced periosteal bone formation by regulating PGE2 release and ERE transcriptional activity in osteoblasts.

Inhibition of neointima formation by local delivery of estrogen receptor alpha and beta specific agonists

Neointima formation is the underlying mechanism of (in-stent) restenosis. 17beta-Estradiol (E2) is known to inhibit injury-induced neointima formation and post-angioplasty restenosis. Estrogen receptor alpha (ERalpha) has been demonstrated to mediate E2 anti-restenotic properties. However, the role of estrogen receptor beta (ERbeta) is not fully elucidated. In the present study, the specific role of vascular ERalpha and ERbeta in neointima formation is assessed. Neointima formation was induced by placement of a perivascular cuff around the femoral artery of male C57BL/6J mice. E2-eluting cuffs significantly inhibited cuff-induced neointima formation. To address the specific roles of ERalpha and ERbeta on neointima formation, the ERalpha-selective agonist 4,4',4''-(4-propyl-[1H]-pyrazole-1,3,5-triyl)tris-phenol (PPT) and the ERbeta-selective agonist 2,3-bis(4-hydroxy-phenyl)-propionitrile (DPN) were applied via a drug-eluting cuff. PPT inhibited neointima formation at low but not at high concentrations. Conversely, DPN inhibited neointima formation dose dependently. To demonstrate the specificity of these responses, an ERalpha-selective antagonist, MPP, was also used in combination with E2, PPT, or DPN. While the effect of PPT on neointima formation inhibition was blocked by co-delivery of MPP, E2 and DPN could still inhibit neointima formation. Our data suggest that, in addition to ERalpha, specific ERbeta activation inhibits neointima formation in a mouse model of restenosis. These data reveal a yet unidentified protective role of ERbeta on neointima formation.

The effect of tamoxifen on bladder functions and histology, and the role of estrogen receptor β in a rat chemical cystitis model

The purpose of this study was to investigate the effect of tamoxifen citrate on bladder functions and histology, and also to investigate the role of estrogen receptor beta (ER beta) in a rat chemical cystitis model. The study included 37 female Sprague-Dawley rats. Chemical cystitis was induced by intravesical instillation of hydrochloric acid in 32 rats, and the treatment group (n = 15) received daily 0.4 mg/kg of tamoxifen citrate with orogastric tube, and the control group (n = 17) received no treatment. The sham group consisted of five rats having no acid instillation and no treatment. Cystometric studies were performed in all rats at the beginning and end of the experiment. The rats were euthanized at 2 months. The bladders were removed and examined histologically for mast cells, inflammatory cells, and ER beta. The mean maximal bladder volume increased by 73.6% +/- 25.2 in the treatment group and decreased by 7.2% +/- 10.8 in the control group, revealing a significant difference (P = 0.007). The mean bladder compliance increased by 81.2% +/- 25.2 in the treatment group and decreased by 4.8% +/- 12.7 in the control group, revealing a significant difference between the two groups (P = 0.005). ER beta positive cells were significantly lower in the bladders with chronic cystitis than in the sham group (P = 0.038). Tamoxifen citrate may be an alternative choice, as easy, to other treatment options in the treatment of chronic inflammatory condition to improve deteriorated bladder function. In addition, ER beta may have a role on chronic bladder inflammation in a rat chemical cystitis model.