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Publication
Journal: Diabetes
May/8/2003
Abstract
The study addressed the role for aldose reductase (AR) in 1) retinal oxidative stress and vascular endothelial growth factor (VEGF) overexpression in early diabetes, and 2) high glucose-induced oxidative stress in retinal endothelial cells. In vivo experiments were performed on control rats and diabetic rats treated with or without low or high dose of the AR inhibitor (ARI) fidarestat (2 or 16 mg. kg(-1). day(-1)). In vitro studies were performed on bovine retinal endothelial cells (BREC) cultured in either 5 or 30 mmol/l glucose with or without 1 micro mol/l fidarestat. Intracellular reactive oxygen species were assessed using the 5-(and-6)-chloromethyl-2',7'-dichlorodihydrofluorescein diacetate (H(2)DCFDA) probe and flow cytometry. Both low and high doses of fidarestat (i.e., the doses that partially and completely inhibited sorbitol pathway hyperactivity) arrested diabetes-induced retinal lipid peroxidation. This was achieved due to upregulation of the key antioxidative defense enzyme activities rather than changes in reduced glutathione, oxidized glutathione, ascorbate and dehydroascorbate concentrations, and the glutathione and ascorbate redox states. Diabetes-associated 2.1-fold VEGF protein overexpression (enzyme-linked immunosorbent assay; ELISA) was dose-dependently prevented by fidarestat, whereas total VEGF mRNA and VEGF-164 mRNA (RT-PCR) abundance were not affected by either diabetes or the ARI. In BREC, fidarestat corrected hyperglycemia-induced increase in H(2)DCFDA fluorescence but not oxidative stress caused by three different pro-oxidants in normoglycemic conditions. In conclusion, increased AR activity contributes to retinal oxidative stress and VEGF protein overexpression in early diabetes. The findings justify the rationale for evaluation of fidarestat on diabetic retinopathy.
Publication
Journal: Oncogene
May/22/2003
Abstract
Prostate cancer (CaP) is initially androgen sensitive and responsive to hormone ablation therapy. However, cancer growth recurs despite androgen deprivation in the majority of cases of advanced disease. The molecular basis of this progression still remains unknown. The significance of androgen receptor (AR) coactivator proteins in this androgen-dependent malignancy is only beginning to emerge. In the present study, we examined the role of Tat interactive protein, 60 kDa (Tip60), an AR coactivator, in CaP progression. In hormone refractory CaP biopsies, we observed a nuclear accumulation of Tip60 expression in contrast to a more diffuse distribution pattern observed in benign prostate hyperplasia and primary CaP. Furthermore, in both the prostate xenograft model CWR22 and the LNCaP CaP cell line, we observed that androgen withdrawal promoted upregulation of Tip60 as well as nuclear accumulation. In contrast, androgen exposure resulted in decreased Tip60 expression that was more closely linked to a cytoplasmic presence. Chromatin immunoprecipitation analysis revealed Tip60's recruitment to the PSA gene promoter in both androgen-dependent and -independent cell lines. Thus, in vitro and in vivo data support a possible role for Tip60 in the molecular pathway leading to the development of androgen-independent CaP following long-term androgen deprivation therapy.
Publication
Journal: Journal of Biological Chemistry
January/27/1993
Abstract
The plasmid-borne arsenical resistance (ars) operon encodes an arsenical-translocating ATPase and confers resistance to antimonials and arsenicals in Escherichia coli by extrusion of the toxic compounds from the cytosol. The trans-acting regulatory ArsR protein was shown to bind to a fragment of DNA containing the ars promoter. Hybrid formation of the ArsR protein with a ArsR-beta-lactamase chimeric protein suggested that the active form of the ArsR repressor is a dimer. From footprinting analysis the binding site was defined as a region of imperfect dyad symmetry just upstream of the -35 site. In vivo the operon was derepressed by oxyions of +III oxidation state of arsenic, antimony, and bismuth, as well as arsenate (As(V)), whereas in vitro ArsR protein-operator interaction was reduced by each of those compounds except arsenate, as determined by gel retardation and DNase I and hydroxyl radical footprinting experiments. This indicates that arsenate is not a true inducer and must be reduced to arsenite in vivo to induce. An operator mutant obtained by deletion of the in vitro ArsR-protected DNA sequence exhibited constitutive ars promoter activity, demonstrating that the binding site is the functional target for the ArsR repressor in vivo.
Authors
Publication
Journal: Journal of Neuroscience
October/23/2002
Abstract
Norepinephrine strengthens the working memory, behavioral inhibition, and attentional functions of the prefrontal cortex through actions at postsynaptic alpha2-adrenoceptors (alpha2-AR). The alpha2-AR agonist guanfacine enhances prefrontal cortical functions in rats, monkeys, and human beings and ameliorates prefrontal cortical deficits in patients with attention deficit hyperactivity disorder. The present study examined the subtype of alpha2-AR underlying these beneficial effects. Because there are no selective alpha2A-AR, alpha2B-AR, or alpha2C-AR agonists or antagonists, genetically altered mice were used to identify the molecular target of the action of guanfacine. Mice with a point mutation of the alpha2A-AR, which serves as a functional knock-out, were compared with wild-type animals and with previously published studies of alpha2C-AR knock-out mice (Tanila et al., 1999). Mice were adapted to handling on a T maze and trained on either a spatial delayed alternation task that is sensitive to prefrontal cortical damage or a spatial discrimination control task with similar motor and motivational demands but no dependence on prefrontal cortex. The effects of guanfacine on performance of the delayed alternation task were assessed in additional groups of wild-type versus alpha2A-AR mutant mice. We observed that functional loss of the alpha2A-AR subtype, unlike knock-out of the alpha2C-AR subtype, weakened performance of the prefrontal cortical task without affecting learning and resulted in loss of the beneficial response to guanfacine. These data demonstrate the importance of alpha2A-AR subtype stimulation for the cognitive functions of the prefrontal cortex and identify the molecular substrate for guanfacine and novel therapeutic interventions.
Publication
Journal: Neuron
November/1/2004
Abstract
Sexually dimorphic behaviors are likely to involve neural pathways that express the androgen receptor (AR). We have genetically modified the AR locus to visualize dimorphisms in neuronal populations that express AR. Analysis of AR-positive neurons reveals both known dimorphisms in the preoptic area of the hypothalamus and the bed nucleus of the stria terminalis as well as novel dimorphic islands in the basal forebrain with a clarity unencumbered by the vast population of AR-negative neurons. This genetic approach allows the visualization of dimorphic subpopulations of AR-positive neurons along with their projections and may ultimately permit an association between neural circuits and specific dimorphic behaviors.
Publication
Journal: Investigative Ophthalmology and Visual Science
May/14/2000
Abstract
OBJECTIVE
Epidermal growth factor (EGF) and related growth factors: transforming growth factor (TGF)-alpha, heprin-ding (HB)-EGF, and amphiregulin (AR), have been shown to stimulate events associated with epithelial wound repair. These growth factors function by binding to a common EGF receptor (EGFR), tyrosine kinase. We have used in vivo and organ culture wound-healing models to examine the kinetics and extent of EGFR activation during corneal epithelial wound repair and whether the epithelium itself produces EGFR ligands capable of stimulating the healing process.
METHODS
In the in vivo model, 3-mm debridement wounds were made in rat corneas and allowed to heal in situ. Activation of EGFR was analyzed by 1) indirect immunofluorescence microscopy, 2) immunoprecipitation using anti-EGFR and anti-phosphotyrosine (anti-PT), and 3) binding-site localization using EGF-fluorescein isothiocyanate (FITC). Relative levels of mRNA for EGF, TGF-alpha, HB-EGF, and AR were determined using reverse transcription-polymerase chain reaction. To determine whether inhibiting EGFR activation slows epithelial migration, wounded corneas were allowed to heal in organ culture in the presence of tyrphostin AG1478 (0-50 microM), a specific inhibitor of EGFR kinase activity.
RESULTS
In unwounded corneas, EGFR was localized in basal cells and appeared to be membranous. Within 1 hour after wounding, EGFR was no longer immunolocalized in the membranes of cells migrating into the wound area. EGF-FITC-binding assays indicated that EGFR ligands could penetrate all the way to the limbus. Immunoprecipitation showed that EGFR was phosphorylated on tyrosine residues within 30 minutes after wounding and that phosphorylation levels increased after wounding. Levels of mRNA for TGF-alpha, HBEGF, and AR all appeared to increase after wounding. In organ culture experiments, tyrphostin AG1478 inhibited migration rates in a dose-dependent manner.
CONCLUSIONS
These data indicate that EGFR was activated during corneal epithelial wound healing in vivo. Furthermore, this activation appears to be a necessary component of the process, because inhibition of the EGFR signaling cascade significantly slowed migration rates.
Publication
Journal: Bone
November/12/2008
Abstract
Whilst exercise is recommended for optimum bone health in adult women, there are few systematic reviews of the efficacy of walking as singular exercise therapy for postmenopausal bone loss. The aim of this study was to assess the effects of prescribed walking programmes on bone mineral density (BMD) at the hip and spine in postmenopausal women and to determine if effects are modified by variations in protocol design. We undertook a systematic review and meta-analysis of randomised (RCTs) and non-randomised controlled trials. Electronic bibliographic databases, key journals and reference lists of reviews and articles were searched to identify studies for inclusion. Randomised and non-randomised controlled trials assessing the effects of walking on lumbar spine, femoral neck and total hip BMD, measured by radiographic techniques, among sedentary postmenopausal women were eligible for inclusion. Two independent reviewers assessed studies for eligibility. Reported absolute BMD outcomes were combined in the analysis. Weighted mean differences (WMD) were calculated using a fixed and random-effects models. Heterogeneity among trials was examined using the Q statistic and I2 methods. Potential publication bias was assessed through funnel plot inspection. Assessment of trial quality was also performed using the widely used instrument devised by Jadad et al. [Jadad AR, Moore RA, Carroll D, Jenkinson C, Reynolds DJM, Gavaghan DJ, et al. Assessing the quality of reports of randomized clinical trials: Is blinding necessary? Cont Clin Trials 1996; 17:1-12]. Eight trials were eligible for inclusion. Treatment duration ranged from 6 to 24 months. All eight trials reported BMD data at the lumbar spine following walking interventions among postmenopausal women. Meta-analysis showed no significant change in BMD at this site [WMD (fixed-effect) 0.007 g/cm2 95% CI (-0.001 to 0.016); P=0.09)]. BMD data at the femoral neck were available from five trials among postmenopausal women. Results were inconsistent (I2=51.4%) in showing a positive effect of walking on BMD at this site [WMD (random-effects) 0.014 g/cm2 95% CI (0.000 to 0.028); P=0.05). Insufficient data were available for meta-analysis of the total hip site. Funnel plots showed some asymmetry for negative lumbar spine BMD outcomes. Trial quality scores ranged from 0 to 3 from the Jadad scale of 0 to 5. We conclude that regular walking has no significant effect on preservation of BMD at the spine in postmenopausal women, whilst significant positive effects at femoral neck are evident. However, diverse methodological and reporting discrepancies are apparent in the published trials on which these conclusions are based. Other forms of exercise that provide greater targeted skeletal loading may be required to preserve bone mineral density in this population.
Publication
Journal: FASEB Journal
January/20/2010
Abstract
Androgens are essential for normal spermatogenesis and male fertility, but how androgens exert this effect remains uncertain. Androgen receptors (ARs) are expressed in several testicular cell types, but continuing uncertainty exists over which cell type mediates androgen control of spermatogenesis. Androgen signaling via Sertoli cells (SCs) is essential for complete spermatogenesis, but the role for androgen signaling via peritubular myoid (PTM) cells is contentious. To address this controversy, we generated PTM-specific AR-knockout (PTM-ARKO) mice in which gross reproductive development was normal, but all PTM-ARKO males were azoospermic and infertile. Testis weight was reduced beyond puberty, and in adulthood there was an 86% reduction in germ cells, compared with wild-type littermates. These changes were not explained by any deficits in testosterone, luteinizing hormone, or follicle-stimulating hormone concentrations. SC function was impaired in PTM-ARKO males, indicated by reduced seminiferous tubule fluid production and reduced expression of some androgen-dependent SC genes. Androgen action via PTM cells is therefore essential for normal testis function, spermatogenesis, and fertility in males. This study also provides the first direct evidence for the importance of androgen-driven stromal-epithelial interactions underpinning the regulation of spermatogenesis; PTM-ARKO mice will enable identification of the new molecular pathways involved.
Publication
Journal: Rheumatology
March/10/2011
Abstract
OBJECTIVE
The aim of this study is to evaluate the clinical manifestation and prognostic factors of anti-melanoma differentiation-associated gene 5 (MDA5) antibody-associated interstitial lung disease (ILD) with DM.
METHODS
Fourteen patients who presented with anti-MDA5 antibody and 10 patients with anti-aminoacyl-tRNA synthetase (ARS) antibody were enrolled. All patients were diagnosed as having DM with ILD. Clinical manifestations in the patients with anti-MDA5 antibody were compared with those in the patients with anti-ARS antibody.
RESULTS
The frequencies of acute/subacute interstitial pneumonia (A/SIP) and fatal outcome were significantly higher in the subset with anti-MDA5 antibody. The creatine kinase (CK) value was significantly lower and the gamma-glutamyl transpeptidase and ferritin values were significantly higher in the subset with anti-MDA5 antibody. Significant correlations were found between PaO(2)/F(i)O(2) and ferritin (r(s) = -0.59, P = 0.035), alveolar-arterial oxygen difference (A-aDO(2)) and KL-6 (r(s) = 0.73, P = 0.016) and A-aDO(2) and ferritin (r(s) = 0.66, P = 0.013) in the subset with anti-MDA5 antibody. The most significant prognostic factor was ferritin. The cumulative survival rate was significantly lower (P < 0.0001) in the subset with ferritin>>or=1600 ng/ml than that in the subset with ferritin <1600 ng/ml in anti-MDA5 antibody-associated ILD.
CONCLUSIONS
Both serum ferritin and anti-MDA5 antibody are powerful indicators for the early diagnosis of A/SIP with DM. Ferritin also predicts disease severity and prognosis for patients with anti-MDA5 antibody. Intensive treatment should be administered to cases that have anti-MDA5 antibody-associated ILD with DM showing hyperferritinaemia, especially if the ferritin level is>>or=1600 ng/ml.
Publication
Journal: Applied and Environmental Microbiology
October/4/2006
Abstract
The strong overexpression or complete deletion of a gene gives only limited information about its control over a certain phenotype or pathway. Gene function studies based on these methods are therefore incomplete. To effect facile manipulation of gene expression across a full continuum of possible expression levels, we recently created a library of mutant promoters. Here, we provide the detailed characterization of our yeast promoter collection comprising 11 mutants of the strong constitutive Saccharomyces cerevisiae TEF1 promoter. The activities of the mutant promoters range between about 8% and 120% of the activity of the unmutated TEF1 promoter. The differences in reporter gene expression in the 11 mutants were independent of the carbon source used, and real-time PCR confirmed that these differences were due to varying levels of transcription (i.e., caused by varying promoter strengths). In addition to a CEN/ARS plasmid-based promoter collection, we also created promoter replacement cassettes. They enable genomic integration of our mutant promoter collection upstream of any given yeast gene, allowing detailed genotype-phenotype characterizations. To illustrate the utility of the method, the GPD1 promoter of S. cerevisiae was replaced by five TEF1 promoter mutants of different strengths, which allowed analysis of the impact of glycerol 3-phosphate dehydrogenase activity on the glycerol yield.
Publication
Journal: Molecular and Cellular Proteomics
February/12/2013
Abstract
Prostate cancer is the leading type of cancer diagnosed in men. In 2010, ~217,730 new cases of prostate cancer were reported in the United States. Prompt diagnosis of the disease can substantially improve its clinical outcome. Improving capability for early detection, as well as developing new therapeutic targets in advanced disease are research priorities that will ultimately lead to better patient survival. Eukaryotic cells secrete proteins via distinct regulated mechanisms which are either ER/Golgi dependent or microvesicle mediated. The release of microvesicles has been shown to provide a novel mechanism for intercellular communication. Exosomes are nanometer sized cup-shaped membrane vesicles which are secreted from normal and cancerous cells. They are present in various biological fluids and are rich in characteristic proteins. Exosomes may thus have potential both in facilitating early diagnosis via less invasive procedures or be candidates for novel therapeutic approaches for castration resistance prostate cancer. Because exosomes have been shown previously to have a role in cell-cell communication in the local tumor microenvironment, conferring activation of numerous survival mechanisms, we characterized constitutive lipids, cholesterol and proteins from exosomes derived from six prostate cell lines and tracked their uptake in both cancerous and benign prostate cell lines respectively. Our comprehensive proteomic and lipidomic analysis of prostate derived exosomes could provide insight for future work on both biomarker and therapeutic targets for the treatment of prostate cancer.
Publication
Journal: Journal of Neuroscience
June/21/2007
Abstract
Spinal and bulbar muscular atrophy (SBMA) is an inherited motor neuron disease caused by the expansion of a polyglutamine tract within the androgen receptor (AR). The pathologic features of SBMA are motor neuron loss in the spinal cord and brainstem and diffuse nuclear accumulation and nuclear inclusions of the mutant AR in the residual motor neurons and certain visceral organs. Many components of the ubiquitin-proteasome and molecular chaperones are also sequestered in the inclusions, suggesting that they may be actively engaged in an attempt to degrade or refold the mutant AR. C terminus of Hsc70 (heat shock cognate protein 70)-interacting protein (CHIP), a U-box type E3 ubiquitin ligase, has been shown to interact with heat shock protein 90 (Hsp90) or Hsp70 and ubiquitylates unfolded proteins trapped by molecular chaperones and degrades them. Here, we demonstrate that transient overexpression of CHIP in a neuronal cell model reduces the monomeric mutant AR more effectively than it does the wild type, suggesting that the mutant AR is more sensitive to CHIP than is the wild type. High expression of CHIP in an SBMA transgenic mouse model also ameliorated motor symptoms and inhibited neuronal nuclear accumulation of the mutant AR. When CHIP was overexpressed in transgenic SBMA mice, mutant AR was also preferentially degraded over wild-type AR. These findings suggest that CHIP overexpression ameliorates SBMA phenotypes in mice by reducing nuclear-localized mutant AR via enhanced mutant AR degradation. Thus, CHIP overexpression would provide a potential therapeutic avenue for SBMA.
Publication
Journal: Journal of Neuroscience
May/5/2009
Abstract
Testosterone (T) profoundly influences central sexual differentiation and functions. In the brain, T signals either directly through androgen receptor (AR) or indirectly through estrogen receptor (ER) following aromatization into E2 (17-beta-estradiol). As T, through AR, also controls peripheral male sexual differentiation, the relative contribution of central AR in T-mediated regulation of behavioral and neuroendocrine responses still remains unclear. To address this question, we generated, by using Cre-loxP technology, mice selectively lacking AR expression in the nervous system. The mutant male urogenital tract was normally developed, and mice were able to produce offspring. Nonetheless, sexual motivation and performance as well as aggressive behaviors were affected. Only a low percentage of males displayed a complete sexual behavior and offensive attacks. The latency to show masculine behaviors was increased and copulation length prolonged. Erectile activity during mating was also altered. These alterations occurred despite increased levels of T and its metabolites, and an unaffected number of ERalpha-immunoreactive cells. Olfactory preference and neuronal activation, mapped by Fos immunoreactivity, following exposure to estrus female-soiled bedding were also normal. At comparable T levels, greater differences in masculine behaviors were observed between gonadectomized control and mutant males. AR invalidation in the nervous system also disrupted the somatotropic axis since mutant males exhibited growth retardation and decreased serum levels of insulin-like growth factor I. Our findings show that central AR is required in T-induced regulation of male-typical behaviors and gonadotrope and somatotropic axes. This genetic model offers a unique opportunity in the understanding of AR's role in cerebral functions of T.
Publication
Journal: Otolaryngology - Head and Neck Surgery
March/25/2015
Abstract
OBJECTIVE
Allergic rhinitis (AR) is one of the most common diseases affecting adults. It is the most common chronic disease in children in the United States today and the fifth most common chronic disease in the United States overall. AR is estimated to affect nearly 1 in every 6 Americans and generates $2 to $5 billion in direct health expenditures annually. It can impair quality of life and, through loss of work and school attendance, is responsible for as much as $2 to $4 billion in lost productivity annually. Not surprisingly, myriad diagnostic tests and treatments are used in managing this disorder, yet there is considerable variation in their use. This clinical practice guideline was undertaken to optimize the care of patients with AR by addressing quality improvement opportunities through an evaluation of the available evidence and an assessment of the harm-benefit balance of various diagnostic and management options.
OBJECTIVE
The primary purpose of this guideline is to address quality improvement opportunities for all clinicians, in any setting, who are likely to manage patients with AR as well as to optimize patient care, promote effective diagnosis and therapy, and reduce harmful or unnecessary variations in care. The guideline is intended to be applicable for both pediatric and adult patients with AR. Children under the age of 2 years were excluded from the clinical practice guideline because rhinitis in this population may be different than in older patients and is not informed by the same evidence base. The guideline is intended to focus on a limited number of quality improvement opportunities deemed most important by the working group and is not intended to be a comprehensive reference for diagnosing and managing AR. The recommendations outlined in the guideline are not intended to represent the standard of care for patient management, nor are the recommendations intended to limit treatment or care provided to individual patients.
UNASSIGNED
The development group made a strong recommendation that clinicians recommend intranasal steroids for patients with a clinical diagnosis of AR whose symptoms affect their quality of life. The development group also made a strong recommendation that clinicians recommend oral second-generation/less sedating antihistamines for patients with AR and primary complaints of sneezing and itching. The panel made the following recommendations: (1) Clinicians should make the clinical diagnosis of AR when patients present with a history and physical examination consistent with an allergic cause and 1 or more of the following symptoms: nasal congestion, runny nose, itchy nose, or sneezing. Findings of AR consistent with an allergic cause include, but are not limited to, clear rhinorrhea, nasal congestion, pale discoloration of the nasal mucosa, and red and watery eyes. (2) Clinicians should perform and interpret, or refer to a clinician who can perform and interpret, specific IgE (skin or blood) allergy testing for patients with a clinical diagnosis of AR who do not respond to empiric treatment, or when the diagnosis is uncertain, or when knowledge of the specific causative allergen is needed to target therapy. (3) Clinicians should assess patients with a clinical diagnosis of AR for, and document in the medical record, the presence of associated conditions such as asthma, atopic dermatitis, sleep-disordered breathing, conjunctivitis, rhinosinusitis, and otitis media. (4) Clinicians should offer, or refer to a clinician who can offer, immunotherapy (sublingual or subcutaneous) for patients with AR who have inadequate response to symptoms with pharmacologic therapy with or without environmental controls. The panel recommended against (1) clinicians routinely performing sinonasal imaging in patients presenting with symptoms consistent with a diagnosis of AR and (2) clinicians offering oral leukotriene receptor antagonists as primary therapy for patients with AR. The panel group made the following options: (1) Clinicians may advise avoidance of known allergens or may advise environmental controls (ie, removal of pets; the use of air filtration systems, bed covers, and acaricides [chemical agents formulated to kill dust mites]) in patients with AR who have identified allergens that correlate with clinical symptoms. (2) Clinicians may offer intranasal antihistamines for patients with seasonal, perennial, or episodic AR. (3) Clinicians may offer combination pharmacologic therapy in patients with AR who have inadequate response to pharmacologic monotherapy. (4) Clinicians may offer, or refer to a surgeon who can offer, inferior turbinate reduction in patients with AR with nasal airway obstruction and enlarged inferior turbinates who have failed medical management. (5) Clinicians may offer acupuncture, or refer to a clinician who can offer acupuncture, for patients with AR who are interested in nonpharmacologic therapy. The development group provided no recommendation regarding the use of herbal therapy for patients with AR.
Publication
Journal: Molecular Pharmacology
July/21/2003
Abstract
The P2Y13 receptor has recently been identified as a new P2Y receptor sharing a high sequence homology with the P2Y12 receptor as well as similar functional properties: coupling to Gi and responsiveness to ADP (Communi et al., 2001). In the present study, the pharmacology of the P2Y13 receptor and its differences with that of the P2Y12 receptor have been further characterized in 1321N1 cells (binding of [33P]2-methylthio-ADP (2MeSADP) and of GTPgamma[35S]), 1321N1 cells coexpressing Galpha16 [AG32 cells: inositol trisphosphate (IP3) measurement, binding of GTPgamma[35S]) and Chinese hamster ovary (CHO)-K1 cells (cAMP assay)]. 2MeSADP was more potent than ADP in displacing [33P]2MeSADP bound to 1321N1 cells and increasing GTPgamma[35S] binding to membranes prepared from the same cells. Similarly, 2MeSADP was more potent than ADP in stimulating IP3 accumulation after 10 min in AG32 cells and increasing cAMP in pertussis toxin-treated CHO-K1 cells stimulated by forskolin. On the other hand, ADP and 2MeSADP were equipotent at stimulating IP3 formation in AG32 cells after 30 s and inhibiting forskolininduced cAMP accumulation in CHO-K1 cells. These differences in potency cannot be explained by differences in degradation rate, which in AG32 cells was similar for the two nucleotides. When contaminating diphosphates were enzymatically removed and assay of IP3 was performed after 30 s, ATP and 2MeSATP seemed to be weak partial agonists of the P2Y13 receptor expressed in AG32 cells. The stimulatory effect of ADP on the P2Y13 receptor in AG32 cells was antagonized by reactive blue 2, suramin, pyridoxal-phosphate-6-azophenyl-2',4'disulfonic acid, diadenosine tetraphosphate, and 2-(propylthio)-5'-adenylic acid, monoanhydride with dichloromethylenebis (phosphonic acid) (AR-C67085MX), but not by N6-methyl 2'-deoxyadenosine 3',5'-bisphosphate (MRS-2179) (up to 100 microM). The most potent antagonist was N6-(2-methylthioethyl)-2-(3,3,3-trifluoropropylthio)-5'-adenylic acid, monoanhydride with dichloromethylenebis (phosphonic acid) (ARC69931MX) (IC50 = 4 nM), which behaved in a noncompetitive way. The active metabolite of clopidogrel was unable to displace bound 2MeSADP at concentrations up to 2 microM.
Publication
Journal: British Journal of Pharmacology
January/23/2000
Abstract
1 The human P2Y11 receptor is coupled to both the phosphoinositide and the cyclic AMP pathways. A pharmacological characterization of the recombinant human P2Y11 receptor has been conducted following stable expression in two different cell lines: the 1321N1 astrocytoma cells for inositol trisphosphate measurements and the CHO-K1 cells for cyclic AMP assays. The rank order of potency of a series of nucleotides was almost identical for the two pathways: ATPgammaS approximately BzATP>> dATP>> ATP>> ADPbetaS>> 2MeSATP. 2 ADPbetaS, AMPalphaS and A3P5PS behaved as partial agonists of the human P2Y11 receptor. At high concentrations, these three nucleotides were able to partially inhibit the ATP response. 3 Suramin was a more potent antagonist than reactive blue 2, whereas pyridoxal-phosphate-6-azophenyl-2',4'-disulphonic acid was completely inactive. The P2Y11 receptor proved to be sensitive to suramin in a competitive way with an apparent Ki value of 0.82+/-0. 07 microM. 4 The ATP derivative AR-C67085 (2-propylthio-beta, gamma-dichloromethylene-D-ATP), a potent inhibitor of ADP-induced platelet aggregation, was the most potent agonist of the P2Y11 receptor, among the various nucleotides tested. 5 The pharmacological profile of the recombinant human P2Y11 receptor is closely similar to that of the cyclic AMP-coupled P2 receptor recently described in HL-60 cells, suggesting that it is the same receptor.
Publication
Journal: Breast Cancer Research and Treatment
February/17/2011
Abstract
The purpose of this article is to evaluate the prognostic value of androgen receptor (AR) expression in patients with estrogen receptor (ER)-positive breast cancer, treated with endocrine therapy, with or without the addition of chemotherapy. A consecutive series of 953 patients with ER-positive breast cancer, treated between 1998 and 2003, was selected. Repeated immunohistochemistry confirmed the expression of ER in the tumor of 938 patients. AR expression was measured by immunohistochemistry. The Kaplan-Meier method, logrank test and multivariate Cox models were used to explore the impact of AR expression on time to relapse (TTR) and disease specific survival (DSS) in all patients and in subgroups treated with chemo-endocrine therapy or endocrine therapy alone. AR immunoreactivity was assessable in 859 tumors and positive in 609 (70.9%). AR expression was a significant marker of good prognosis for TTR (P = 0.001) and DSS (P < 0.001). This effect was particularly evident in the group of patients receiving chemo-endocrine therapy (TTR (P = 0.015) and DSS (P < 0.001)). Cox models confirmed AR as an independent variable for both TTR (P = 0.003, HR 0.444, 95%CI 0.258-0.765) and DSS (P < 0.001, HR 0.135, 95%CI 0.054-0.337). Thus, we focused on ER-positive luminal B breast cancer that may be selected for chemotherapy because of their more aggressive immunophenotype. In this subset AR expression identified a group of patients with better prognosis for TTR (P = 0.017, HR 0.521, 95%CI 0.306-0.888) and DSS (P = 0.001, HR 0.276, 95% CI 0.130-0.588). AR expression is an independent prognostic factor of better outcome in patients with ER-positive breast cancers.
Publication
Journal: Journal of Histochemistry and Cytochemistry
August/7/2002
Abstract
During the course of diagnostic surgical pathology, pathologists have established a large collection of formalin-fixed, paraffin-embedded tissues that form invaluable resources for translational studies of cancer and a variety of other diseases. Accessibility of macromolecules in the fixed tissue specimens is a critical issue as exemplified by heat-induced antigen retrieval (AR) immunohistochemical (IHC) staining. On the basis of observations that heating may also enhance in situ hybridization (ISH) and the similarity of formalin-induced chemical modifications that occur in protein and in DNA, we designed a study to examine the efficiency of DNA extraction from archival formalin-fixed, paraffin-embedded tissues using an adaptation of the basic principles of the AR technique, i.e., heating the tissue under the influence of different pH values. Archival paraffin blocks of lymph nodes, tonsil, and colon were randomly selected. Each paraffin block was prepared in 34 microtubes. For each paraffin block, one tube was used as a control sample, using a non-heating DNA extraction protocol. The other 33 tubes were tested using a heating protocol under 11 variable pH values (pH 2 to 12) under three different heating conditions (80, 100, and 120C). Evaluation of the results of DNA extraction was carried out by measuring yields by photometry and PCR amplification, as well as kinetic thermocycling (KTC)-PCR methods. In general, lower pH (acid) solutions gave inferior results to solutions at higher pH (alkaline). Heating tissues at a higher temperature and at pH 6-9 gave higher yields of DNA. There appeared to be a peak in terms of highest efficiency of extracted DNA at around pH 9. The average ratios 260:280 of extracted DNA also showed better values for samples heated at 120C. PCR products of three primers showed satisfactory results for DNA extracted from archival paraffin-embedded tissues by heating protocols at pH 6-12, with results that were comparable to the control sample subjected to the standard non-heating, enzymatic DNA extraction method. This study is the first to document the use of heating at an alkaline pH for DNA extraction from archival formalin-fixed, paraffin-embedded tissues, a recommendation based on the principles of AR for protein IHC. These findings may lead to a more effective protocol for DNA extraction from archival paraffin-embedded tissues and may also provide enhanced understanding of changes that occur during formalin-induced modification of nucleic acids.
Publication
Journal: Pharmacology and Therapeutics
September/5/2001
Abstract
Adrenergic receptors (ARs) are members of the G-protein-coupled receptor family, which includes alpha 1ARs, alpha 2ARs, beta 1ARs, beta 2ARs, beta 3ARs, adenosine, muscarinic, angiotensin, endothelin receptors, and many others that are responsible for a large variety of physiologic effects through G-protein coupling. This review focuses on alpha 1ARs and their regulation at both the mRNA and protein levels. Currently, three alpha 1AR subtypes have been characterized both pharmacologically and at the gene level: alpha 1aAR, alpha 1bAR, and alpha 1dAR. These are expressed in a species- and tissue-dependent manner. Mutagenesis approaches have been extremely valuable in the identification of key residues that govern alpha 1AR ligand binding and signaling. These studies reveal that alpha 1ARs have evolved an exquisitely sensitive regulation of their activity in which any disruption of the native structure has profound effects on subsequent function and effector coupling. Significant advances have also been made in the elucidation of signaling pathway components, resulting in the identification of novel pathways that can lead to pathologic conditions. Specific topics include mitogen-activated protein kinase, phosphatidylinositol 3-kinase, and G-protein-coupled receptor cross-talk pathways. Within this context, recent studies identifying underlying transcriptional mechanisms involved in the regulation of the alpha 1AR subtypes are also discussed. Finally, given the potentially important role of alpha 1ARs in the vasculature, as well as in the pathology of many diseases, such as myocardial hypertrophy and benign prostatic hyperplasia, the clinical relevance of alpha 1AR distribution, pharmacology, and therapeutic intervention is reviewed.
Publication
Journal: Cancer
August/28/2003
Abstract
BACKGROUND
Several studies have demonstrated the biologic and therapeutic significance of estrogen and progesterone receptors (ER and PR) in breast carcinomas. The aim of the current study was to examine the presence of androgen receptors (AR) in breast carcinomas.
METHODS
Two hundred cases of breast carcinoma, consisting of 145 invasive and 55 noninvasive (ductal carcinoma in situ [DCIS]) lesions, were examined using a monoclonal antibody against AR on formalin-fixed, paraffin-embedded archival material. The results were analyzed for correlations with immunohistochemically determined ER, PR, and HER-2/neu expression.
RESULTS
Eighty-seven of the 145 cases (60%) of invasive carcinoma and 45 of the 55 cases (82%) of DCIS were AR-positive according to internationally standardized guidelines. The vast majority of Grade 1 carcinomas were positive for AR (90% of invasive Grade 1 carcinomas and 95% of Grade 1 DCIS), whereas in Grade 3 invasive carcinomas and DCIS, positive immunoreactions for AR were observed in 46% and 76% of cases, respectively. Among the cases of Grade 3 carcinoma, 33 invasive carcinomas (39%) and 17 DCIS lesions (68%) were ER-negative but AR-positive. Among Grade 1 carcinomas (invasive and DCIS), not a single case was positive for HER-2/neu, but most cases were intensely positive for AR. In contrast, many invasive Grade 3 carcinomas exhibited agreement between AR status and HER-2/neu status (AR-positive and HER-2/neu-positive, 30.5%; AR-negative and HER-2/neu-negative, 42.5%).
CONCLUSIONS
Androgen receptors are commonly expressed in DCIS and in invasive breast carcinoma. A significant number of poorly differentiated carcinomas are ER-negative and PR-negative but AR-positive. Immunohistochemical examination of AR would be desirable because it would provide additional information about steroid receptors in breast carcinomas.
Publication
Journal: Environmental Health Perspectives
November/9/2004
Abstract
We tested 200 pesticides, including some of their isomers and metabolites, for agonism and antagonism to two human estrogen receptor (hER) subtypes, hERalpha and hERbeta, and a human androgen receptor (hAR) by highly sensitive transactivation assays using Chinese hamster ovary cells. The test compounds were classified into nine groups: organochlorines, diphenyl ethers, organophosphorus pesticides, pyrethroids, carbamates, acid amides, triazines, ureas, and others. These pesticides were tested at concentrations < 10-5 M. Of the 200 pesticides tested, 47 and 33 showed hER- and hERbeta-mediated estrogenic activities, respectively. Among them, 29 pesticides had both hERalpha and hERbeta agonistic activities, and the effects of the organochlorine insecticides beta-benzene hexachloride (BHC) and delta-BHC and the carbamate insecticide methiocarb were predominantly hERbeta rather than hERalpha agonistic. Weak antagonistic effects toward hERalpha and hERbeta were shown in five and two pesticides, respectively. On the other hand, none of tested pesticides showed hAR-mediated androgenic activity, but 66 of 200 pesticides exhibited inhibitory activity against the transcriptional activity induced by 5alpha-dihydrotestosterone. In particular, the antiandrogenic activities of two diphenyl ether herbicides, chlornitrofen and chlomethoxyfen, were higher than those of vinclozolin and p,p -dichlorodiphenyl dichloroethylene, known AR antagonists. The results of our ER and AR assays show that 34 pesticides possessed both estrogenic and antiandrogenic activities, indicating pleiotropic effects on hER and hAR. We also discussed chemical structures related to these activities. Taken together, our findings suggest that a variety of pesticides have estrogenic and/or antiandrogenic potential via ER and/or AR, and that numerous other manmade chemicals may also possess such estrogenic and antiandrogenic activities.
Publication
Journal: Journal of Agricultural and Food Chemistry
March/29/2005
Abstract
Turmeric, the rhizome of Curcuma longa L., has a wide range of effects on human health. The chemistry includes curcuminoids and sesquiterpenoids as components, which are known to have antioxidative, anticarcinogenic, and antiinflammatory activities. In this study, we investigated the effects of three turmeric extracts on blood glucose levels in type 2 diabetic KK-A(y) mice (6 weeks old, n = 5/group). These turmeric extracts were obtained by ethanol extraction (E-ext) to yield both curcuminoids and sesquiterpenoids, hexane extraction (H-ext) to yield sesquiterpenoids, and ethanol extraction from hexane-extraction residue (HE-ext) to yield curcuminoids. The control group was fed a basal diet, while the other groups were fed a diet containing 0.1 or 0.5 g of H-ext or HE-ext/100 g of diet or 0.2 or 1.0 g of E-ext/100 g of diet for 4 weeks. Although blood glucose levels in the control group significantly increased (P < 0.01) after 4 weeks, feeding of 0.2 or 1.0 g of E-ext, 0.5 g of H-ext, and 0.5 g of HE-ext/100 g of diet suppressed the significant increase in blood glucose levels. Furthermore, E-ext stimulated human adipocyte differentiation, and these turmeric extracts had human peroxisome proliferator-activated receptor-gamma (PPAR-gamma) ligand-binding activity in a GAL4-PPAR-gamma chimera assay. Also, curcumin, demethoxycurcumin, bisdemethoxycurcumin, and ar-turmerone had PPAR-gamma ligand-binding activity. These results indicate that both curcuminoids and sesquiterpenoids in turmeric exhibit hypoglycemic effects via PPAR-gamma activation as one of the mechanisms, and suggest that E-ext including curcuminoids and sesquiterpenoids has the additive or synergistic effects of both components.
Publication
Journal: European Journal of Neuroscience
August/16/2005
Abstract
Though overlapping in distribution within the posterior hypothalamus, neurons containing orexin (Orx) and melanin concentrating hormone (MCH) may play different roles in the regulation of behavioural state. In the present study in rats, we tested whether they express c-Fos differently after total sleep deprivation (SD) vs. sleep recovery (SR). Whereas c-Fos expression was increased in Orx neurons after SD, it was increased in MCH neurons after SR. We reasoned that Orx and MCH neurons could be differently modulated by noradrenaline (NA) and accordingly bear different adrenergic receptors (ARs). Of all Orx neurons (estimated at approximately 6700), substantial numbers were immunostained for the alpha1A-AR, including cells expressing c-Fos after SD. Yet, substantial numbers were also immunostained for the alpha2A-AR, also including cells expressing c-Fos after SD. Of all MCH neurons (estimated at approximately 12,300), rare neurons were immunostained for the alpha1A-AR, whereas significant numbers were immunostained for the alpha2A-AR, including cells expressing c-Fos after SR. We conclude that Orx neurons may act to sustain waking during sleep deprivation, whereas MCH neurons may act to promote sleep following sustained waking. Some Orx neurons would participate in the maintenance of waking during deprivation when excited by NA through alpha1-ARs, whereas MCH neurons would participate in sleep recovery after deprivation when released from inhibition by NA through alpha2-ARs. On the other hand, under certain conditions, Orx neurons may also be submitted to an inhibitory influence by NA through alpha2-ARs.
Publication
Journal: Breast Cancer Research and Treatment
July/12/2010
Abstract
Although the androgen receptor (AR) is a known clinical target in prostate cancer, little is known about its possible role in breast cancer. We have investigated the role of AR expression in human breast cancer in response to treatment with the antiestrogen tamoxifen. Resistance to tamoxifen is a major problem in treating women with breast cancer. By gene expression profiling, we found elevated AR and reduced estrogen receptor (ER) alpha mRNA in tamoxifen-resistant tumors. Exogenous overexpression of AR rendered ERalpha-positive MCF-7 breast cancer cells resistant to the growth-inhibitory effects of tamoxifen in anchorage-independent growth assays and in xenograft studies in athymic nude mice. AR-overexpressing cells remained sensitive to growth stimulation with dihydrotestosterone. Treatment with the AR antagonist Casodex (bicalutamide) reversed this resistance, demonstrating the involvement of AR signaling in tamoxifen resistance. In AR-overexpressing cells, tamoxifen induced transcriptional activation by ERalpha that could be blocked by Casodex, suggesting that AR overexpression enhances tamoxifen's agonistic properties. Our data suggest a role for AR overexpression as a novel mechanism of hormone resistance, so that AR may offer a new clinical therapeutic target in human breast cancers.
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