Estrogen receptors alpha and beta in male and female gerbil prostates

The Mongolian gerbil (Meriones unguiculatus, Gerbilinae: Muridae) is useful for prostate studies, because both males and females spontaneously develop prostatic disorders with age. Estrogens regulate prostate homeostasis via two estrogen receptors, ER alpha (ESR1) and ER beta (ESR2), but the cellular distribution and regulation of these receptors in the gerbil prostate has not been described. Both receptors were localized by immunohistochemistry in the ventral prostate of intact male and female gerbils, in males 7 and 21 days after castration, and in females treated with testosterone for 7 and 21 days. In male and female adult gerbils, ER alpha was detected mainly in prostatic stromal cells, whereas ER beta was present mostly in secretory and basal cells. More ER alpha-positive stromal cells were found in females than in males, as was a reduction toward the male value in females treated with testosterone. Castration did not alter ER alpha expression. Testosterone was necessary for maintenance of ER beta in the male prostate epithelium: ER beta expression declined markedly in prostates of males older than 1 yr, and castration of 4-mo-old males caused a reduction in ER beta to levels seen in 1-yr-old males. Because ER beta is an antiproliferative receptor, its loss with age may predispose the aging gerbil to proliferative diseases of the prostate. © 2013 by the Society for the Study of Reproduction, Inc.

Maternal Thyroid and Glucocorticoid Hormone Interactions in Larval Fish Development, and Their Applications in Aquaculture

Thyroid hormones (THs) have long been known to have regulatory roles in the differentiation and maturation of vertebrate embryos, beginning with the knowledge that hormones of maternal origin are essential for human fetal central nervous and respiratory system development. Precise measurements of circulating THs led to insights into their critically important actions throughout vertebrate growth and development, initially with amphibian metamorphosis and including embryogenesis in fishes. Thyroid cues for larval fish differentiation are enhanced by glucocorticoid hormones, which promote deiodinase activity and thereby increase the generation of triiodothyronine (T-3) from the less bioactive thyroxin (T-4). Glucocorticoids also induce the expression of thyroid hormone receptors in some vertebrates. Maternally derived thyroid hormones and cortisol are deposited in fish egg yolk and accelerate larval organ system differentiation until larvae become capable of endogenous endocrine function. Increases in the T-3/T-4 ratio during larval development may reflect the regulatory importance of maternal thyroid hormones. Experimental applications of individual hormones have produced mixed results, but treatments with combinations of thyroid and corticoid hormones consistently promote larval fish development and improve survival rates. The developmental and survival benefits of maternal endocrine provisioning are increased in viviparous fishes, in which maternal/larval chemical contact is prolonged. Treatments with exogenous thyroid and corticoid hormones consistently promote development and reduce mortality rates in larval fishes, with potential hatchery-scale applications in aquaculture.

Gene and protein expression of oestrogen-beta and progesterone receptors in facial melasma and adjacent healthy skin in women

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Coordinated expression of oestrogen and androgen receptors in HER2-positive breast carcinomas: impact on proliferative activity

Aims Human epidermal growth factor receptor 2 (HER2)-positive breast cancers are aggressive neoplasms associated with a variable response to systemic therapies. Therefore, the identification of biomarkers to better characterise this heterogeneity would improve treatment efficacy. The aim of this study was to evaluate the influence of androgen receptor (AR) and oestrogen receptor (ER) on clinicopathological features in a series of HER2-positive breast carcinomas. Methods A total of 104 carcinomas were selected and reviewed. Immunohistochemical studies for ER, progesterone receptor and Ki-67 were analysed on tumour whole histological sections. AR expression was analysed on samples represented on tissue microarrays. According to steroid receptor expression, cases were classified into three groups: AR positive/ER positive (48 cases), AR positive/ER negative (41 cases) and AR negative/ER negative (13 cases). Results AR-positive tumours corresponded to 89 (85.6%) of 104 carcinomas. AR-positive carcinomas were associated with a higher frequency of ER and progesterone receptor co-expression and lower proliferative activity determined by the expression of Ki-67. AR-negative carcinomas were more often high grade. The group of AR-positive/ER-negative carcinomas was associated with the highest frequency of apocrine morphological features. The group of AR-negative/ER-negative carcinomas was associated with the highest proliferative activity and the highest frequency of high histological and nuclear grade. The lowest frequency of high-grade tumours and the lowest proliferative activity were seen among tumours with expression of both receptors. Conclusions These results suggest that co-expression of AR and ER can provide a protective effect based on phenotypical presentation of HER2-positive carcinomas. Furthermore, lack of both steroid hormone receptors characterises the most aggressive phenotype.

Growth hormone response to growth hormone-releasing peptide-2 in growth hormone-deficient Little mice

OBJECTIVE: To investigate a possible direct, growth hormone-releasing, hormone-independent action of a growth hormone secretagogue, GHRP-2, in pituitary somatotroph cells in the presence of inactive growth hormone-releasing hormone receptors. MATERIALS AND METHODS: The responses of serum growth hormone to acutely injected growth hormone-releasing P-2 in lit/litmice, which represent a model of GH deficiency arising frommutated growth hormone-releasing hormone-receptors, were compared to those observed in the heterozygous (lit/+) littermates and wild-type (+/+) C57BL/6J mice. RESULTS: After the administration of 10 mcg of growth hormone-releasing P-2 to lit/lit mice, a growth hormone release of 9.3 +/- 1.5 ng/ml was observed compared with 1.04 +/- 1.15 ng/ml in controls (p<0.001). In comparison, an intermediate growth hormone release of 34.5 +/- 9.7 ng/ml and a higher growth hormone release of 163 +/- 46 ng/ml were induced in the lit/+ mice and wild-type mice, respectively. Thus, GHRP-2 stimulated growth hormone in the lit/lit mice, and the release of growth hormone in vivo may be only partially dependent on growth hormone-releasing hormone. Additionally, the plasma leptin and ghrelin levels were evaluated in the lit/lit mice under basal and stimulated conditions. CONCLUSIONS: Here, we have demonstrated that lit/lit mice, which harbor a germline mutation in the Growth hormone-releasing hormone gene, maintain a limited but statistically significant growth hormone elevation after exogenous stimulation with GHRP-2. The present data probably reflect a direct, growth hormone-independent effect on Growth hormone S (ghrelin) stimulation in the remaining pituitary somatotrophs of little mice that is mediated by growth hormone S-R 1a.

Growth hormone response to growth hormone-releasing peptide-2 in growth hormone-deficient Little mice

OBJECTIVE: To investigate a possible direct, growth hormone-releasing, hormone-independent action of a growth hormone secretagogue, GHRP-2, in pituitary somatotroph cells in the presence of inactive growth hormonereleasing hormone receptors. MATERIALS AND METHODS: The responses of serum growth hormone to acutely injected growth hormone-releasing P-2 in lit/litmice, which represent a model of GH deficiency arising frommutated growth hormone-releasing hormonereceptors, were compared to those observed in the heterozygous (lit/+) littermates and wild-type (+/+) C57BL/6J mice. RESULTS: After the administration of 10 mcg of growth hormone-releasing P-2 to lit/lit mice, a growth hormone release of 9.3±1.5 ng/ml was observed compared with 1.04±1.15 ng/ml in controls (p<0.001). In comparison, an intermediate growth hormone release of 34.5±9.7 ng/ml and a higher growth hormone release of 163±46 ng/ml were induced in the lit/+ mice and wild-type mice, respectively. Thus, GHRP-2 stimulated growth hormone in the lit/lit mice, and the release of growth hormone in vivo may be only partially dependent on growth hormone-releasing hormone. Additionally, the plasma leptin and ghrelin levels were evaluated in the lit/lit mice under basal and stimulated conditions. CONCLUSIONS: Here, we have demonstrated that lit/lit mice, which harbor a germline mutation in the Growth hormone-releasing hormone gene, maintain a limited but statistically significant growth hormone elevation after exogenous stimulation with GHRP-2. The present data probably reflect a direct, growth hormone-independent effect on Growth hormone S (ghrelin) stimulation in the remaining pituitary somatotrophs of little mice that is mediated by growth hormone S-R 1a.

Glucose-dependent insulinotropic polypeptide receptors in most gastroenteropancreatic and bronchial neuroendocrine tumors

Gastrointestinal peptide hormone receptors overexpressed in neuroendocrine tumors (NET), such as somatostatin or glucagon-like peptide-1 (GLP-1) receptors, are used for in vivo tumor targeting. Unfortunately, not all NET express these receptors sufficiently.

Re-evaluating adjuvant breast cancer trials: assessing hormone receptor status by immunohistochemical versus extraction assays

BACKGROUND: Tumor levels of steroid hormone receptors, a factor used to select adjuvant treatment for early-stage breast cancer, are currently determined with immunohistochemical assays. These assays have a discordance of 10%-30% with previously used extraction assays. We assessed the concordance and predictive value of hormone receptor status as determined by immunohistochemical and extraction assays on specimens from International Breast Cancer Study Group Trials VIII and IX. These trials predominantly used extraction assays and compared adjuvant chemoendocrine therapy with endocrine therapy alone among pre- and postmenopausal patients with lymph node-negative breast cancer. Trial conclusions were that combination therapy provided a benefit to pre- and postmenopausal patients with estrogen receptor (ER)-negative tumors but not to ER-positive postmenopausal patients. ER-positive premenopausal patients required further study. METHODS: Tumor specimens from 571 premenopausal and 976 postmenopausal patients on which extraction assays had determined ER and progesterone receptor (PgR) levels before randomization from October 1, 1988, through October 1, 1999, were re-evaluated with an immunohistochemical assay in a central pathology laboratory. The endpoint was disease-free survival. Hazard ratios of recurrence or death for treatment comparisons were estimated with Cox proportional hazards regression models, and discriminatory ability was evaluated with the c index. All statistical tests were two-sided. RESULTS: Concordance of hormone receptor status determined by both assays ranged from 74% (kappa = 0.48) for PgR among postmenopausal patients to 88% (kappa = 0.66) for ER in postmenopausal patients. Hazard ratio estimates were similar for the association between disease-free survival and ER status (among all patients) or PgR status (among postmenopausal patients) as determined by the two methods. However, among premenopausal patients treated with endocrine therapy alone, the discriminatory ability of PgR status as determined by immunohistochemical assay was statistically significantly better (c index = 0.60 versus 0.51; P = .003) than that determined by extraction assay, and so immunohistochemically determined PgR status could predict disease-free survival. CONCLUSIONS: Trial conclusions in which ER status (for all patients) or PgR status (for postmenopausal patients) was determined by immunohistochemical assay supported those determined by extraction assays. However, among premenopausal patients, trial conclusions drawn from PgR status differed--immunohistochemically determined PgR status could predict response to endocrine therapy, unlike that determined by the extraction assay.

Secretin receptors in the human liver: expression in biliary tract and cholangiocarcinoma, but not in hepatocytes or hepatocellular carcinoma

BACKGROUND/AIMS: Gut hormone receptors are over-expressed in human cancer and allow receptor-targeted tumor imaging and therapy. A novel promising receptor for these purposes is the secretin receptor. The secretin receptor expression was investigated in the human liver because the liver is a physiological secretin target and because novel diagnostic and treatment modalities are needed for liver cancer. METHODS: Nineteen normal livers, 10 cirrhotic livers, 35 cholangiocarcinomas, and 45 hepatocellular carcinomas were investigated for secretin receptor expression by in vitro receptor autoradiography using (125)I-[Tyr(10)] rat secretin and, in selected cases, for secretin receptor mRNA by RT-PCR. RESULTS: Secretin receptors were present in normal bile ducts and ductules, but not in hepatocytes. A significant receptor up-regulation was observed in ductular reaction in liver cirrhosis. Twenty-two (63%) cholangiocarcinomas were positive for secretin receptors, while hepatocellular carcinomas were negative. RT-PCR revealed wild-type receptor mRNA in the non-neoplastic liver, wild-type and spliced variant receptor mRNAs in cholangiocarcinomas found receptor positive in autoradiography experiments, and no receptor transcripts in autoradiographically negative cholangiocarcinomas. CONCLUSIONS: The expression of secretin receptors in the biliary tract is the molecular basis of the secretin-induced bicarbonate-rich choleresis in man. The high receptor expression in cholangiocarcinomas may be used for in vivo secretin receptor-targeting of these tumors and for the differential diagnosis with hepatocellular carcinoma.

NPY receptors in human cancer: a review of current knowledge

Many peptide hormone receptors are over-expressed in human cancer, permitting an in vivo targeting of tumors for diagnostic and therapeutic purposes. NPY receptors are novel and promising candidates in this field. Using in vitro receptor autoradiography, Y1 and Y2 receptors have been found to be expressed in breast carcinomas, adrenal gland and related tumors, renal cell carcinomas, and ovarian cancers in both tumor cells and tumor-associated blood vessels. Pathophysiologically, tumoral NPY receptors may be activated by endogenous NPY released from intratumoral nerve fibers or tumor cells themselves, and mediate NPY effects on tumor cell proliferation and tumoral blood supply. Clinically, tumoral NPY receptors may be targeted with NPY analogs coupled with adequate radionuclides or cytotoxic agents for a scintigraphic tumor imaging and/or tumor therapy.

Targeting CCK receptors in human cancers

Gut hormone receptors can be over-expressed in several human cancers and represent the basis for receptor-targeted tumor imaging and therapy. A promising receptor for such clinical applications is the cholecystokinin receptor. Cholecystokinin receptors are expressed in numerous neuroendocrine tumors, in particular medullary thyroid carcinomas and neuroendocrine gut tumors, as well as in stromal tumors. Moreover, several radiolabeled CCK or gastrin analogs have been developed allowing to detect these tumors and their metastases in patients using in vivo cholecystokinin receptor scintigraphy, proving the feasibility of targeting CCK receptors in human tumors in vivo.

Wild-type and splice-variant secretin receptors in lung cancer: overexpression in carcinoid tumors and peritumoral lung tissue

Gastrointestinal peptide hormone receptors, like somatostatin receptors, are often overexpressed in human cancer, allowing receptor-targeted tumor imaging and therapy. A novel candidate for these applications is the secretin receptor recently identified in pancreatic and cholangiocellular carcinomas. In the present study, secretin receptors were assessed in a non-gastrointestinal tissue, the human lung. Non-small-cell lung cancers (n=26), small-cell lung cancers (n=10), bronchopulmonary carcinoid tumors (n=29), and non-neoplastic lung (n=46) were investigated for secretin receptor protein expression with in vitro receptor autoradiography, using (125)I-[Tyr(10)] rat secretin and for secretin receptor transcripts with RT-PCR. Secretin receptor protein expression was found in 62% of bronchopulmonary carcinoids in moderate to high density, in 12% of non-small cell lung cancers in low density, but not in small cell lung cancers. In tumors found to be secretin receptor positive by autoradiography, RT-PCR revealed transcripts for the wild-type secretin receptor and for novel secretin receptor splice variants. In the non-neoplastic lung, secretin receptor protein expression was observed in low density along the alveolar septa in direct tumor vicinity in cases of acute inflammation, but not in histologically normal lung. In the autoradiographically positive peritumoral lung, RT-PCR showed transcripts for the wild-type secretin receptor and for a secretin receptor spliceoform different from those occurring in lung and gut tumors. In conclusion, secretin receptors are new markers for bronchopulmonary carcinoid tumors, and represent the molecular basis for an in vivo targeting of carcinoid tumors for diagnosis and therapy. Furthermore, secretin receptors may play a role in peritumoral lung pathophysiology. Secretin receptor mis-splicing specifically occurs in tumor and non-tumor lung pathology.

Estrogen receptor β expression and androgen receptor phosphorylation correlate with a poor clinical outcome in hormone-naive prostate cancer and are elevated in castration-resistant disease

Patients with advanced prostate cancer (PC) are usually treated with androgen withdrawal. While this therapy is initially effective, nearly all PCs become refractory to it. As hormone receptors play a crucial role in this process, we constructed a tissue microarray consisting of PC samples from 107 hormone-naïve (HN) and 101 castration-resistant (CR) PC patients and analyzed the androgen receptor (AR) gene copy number and the protein expression profiles of AR, Serin210-phosphorylated AR (pAR(210)), estrogen receptor (ER)β, ERα and the proliferation marker Ki67. The amplification of the AR gene was virtually restricted to CR PC and was significantly associated with increased AR protein expression (P<0.0001) and higher tumor cell proliferation (P=0.001). Strong AR expression was observed in a subgroup of HN PC patients with an adverse prognosis. In contrast, the absence of AR expression in CR PC was significantly associated with a poor overall survival. While pAR(210) was predominantly found in CR PC patients (P<0.0001), pAR(210) positivity was observed in a subgroup of HN PC patients with a poor survival (P<0.05). Epithelial ERα expression was restricted to CR PC cells (9%). ERβ protein expression was found in 38% of both HN and CR PCs, but was elevated in matched CR PC specimens. Similar to pAR(210), the presence of ERβ in HN patients was significantly associated with an adverse prognosis (P<0.005). Our results strongly suggest a major role for pAR(210) and ERβ in HN PC. The expression of these markers might be directly involved in CR tumor growth.

Chemopreventive function of retinoid X receptors in human squamous cell carcinoma of the skin

Retinoid therapy has been successful for the treatment of skin squamous cell carcinoma (SCC). A suppression of the predominant retinoid X receptor expressed in skin, retinoid X receptor α (RXRα), has been reported in skin SCC. These observations have led to the hypothesis that retinoid receptor loss contributes to the tumorigenic phenotype of epithelial cancers. To test this hypothesis, the RXRα gene was mapped in order to generate a targeting construct. Additionally the transcriptional regulation of the human RXRα a gene in keratinocytes was characterized after identifying the transcription initiation sites, the promoter, and enhancer regions of this gene. The structure is highly conserved between human and mouse. A nontumorigenic human skin-derived cell line called near diploid immortalized keratinocytes (NIKS) has the advantage of growing as organotypic raft cultures, under physiological conditions closely resembling in-vivo squamous stratification. We have exploited the raft culture technique to develop an in-vitro model for skin SCC progression that includes the NIKS cells, HaCaT cells, a premalignant cell line, and SRB 12-p9 cells, a tumorigenic SCC skin cell line. The differentiation, proliferation and nuclear receptor ligand response characteristics of this system were studied and significant and novel results were obtained. RXRs are obligate heterodimerization partners with many of the nuclear hormone receptors, including retinoic acid receptors (RARs), vitamin D3 receptors (VDR), thyroid hormone receptors (T3 R) and peroxisome proliferator activate receptors (PPARs), which are all known to be active in skin. Treatment of the three cell lines in raft culture with the RXR specific ligand BMS649, BMS961 (RARγ-specific), vitamin D3 (VDR ligand), thryoid hormone (T3R ligand) and clofibrate (PPARa ligand), and the combination of BMS649 with each of the 4 receptor partner ligands, resulted in distinct effects on differentiation, proliferation and apoptosis. The effects of activation of RXRs in each of the four-receptor pathways; in the context of skin SCC progression, with an emphasis on the VDR/RXR pathway, are discussed. These studies will lead to a better understanding of RXRα action in human skin and will help determine its role in SCC tumorigenesis, as well as its potential as a target for the prevention, treatment, and control of skin cancer. ^

Cloning and characterization of a corepressor and potential component of the nuclear hormone receptor repression complex

Nuclear hormone receptors are potent repressors of transcription in the unliganded state. We describe here the cloning of a nuclear receptor corepressor that we call SUN-CoR (Small Unique Nuclear receptor CoRepressor), which shows no homology to previously described nuclear hormone receptor corepressors, N-CoR, or SMRT. SUN-CoR is a highly basic, 16-kDa nuclear protein that is expressed at high levels in adult tissues and is induced during adipocyte and myogenic differentiation. SUN-CoR potentiates transcriptional repression by thyroid hormone receptor and RevErb in vivo, represses transcription when fused to a heterologous DNA binding domain, and interacts with RevErb as well as with thyroid hormone receptor in vitro. SUN-CoR also interacts with N-CoR and SMRT in vitro and with endogenous N-CoR in cells. We conclude that SUN-CoR is a corepressor and may function as an additional component of the complex involved in transcriptional repression by unliganded and orphan nuclear hormone receptors.