Wednesday, October 17

7:30 am Registration Opens

NUCLEAR HORMONE RECEPTORS 
AS THERAPEUTIC TARGETS

2:10 pm Chairperson’s Remarks 
Johan Malm, Ph.D., Karo Bio AB

2:15 Anti-Obesity, Anti-Diabetic, and Lipid Lowering Effects of the Thyroid Receptor Subtype Selective Agonist KB-141 
Gary J. Grover, Ph.D., Physiology and Biophysics, Robert Wood Johnson Medical School
Thyroid hormone receptor subtype-b(TRb) activation increases metabolic rate with a shallow dose-response slope without tachycardia, unlike T3. The TRb selective agonist KB-141, has a 10-30-fold window in lean rats where 5-10% increases in metabolic rate are seen without tachycardia and retention of cholesterol reduction. The purpose of this study was to determine whether KB-141 causes loss of body weight and adiposity, lipid levels, and anti-diabetic effects in obese Zucker fa/fa rats and ob/ob mice. Anti-obesity studies were done in Zucker fa/fa fatty rats; KB-141 was given p.o. at 0.00547, 0.0547, 0.167 or 0.547 mg/kg/day for 21 days and effects on body weight and adiposity (DEXA) were determined. Body weight was significantly reduced by KB-141 by 6 and 8% compared to vehicle treated rats at the 2 higher doses with no tachycardia. At 0.167 mg/kg/day, KB-141 reduced adiposity (DEXA) and body weight by approximately 5-6%. For the lipid-lowering studies, ob/ob mice were treated for 7 days with 0.5 mg/kg/day KB-141 and significant serum cholesterol and triglyceride lowering (35% vs vehicle, respectively) as reduced serum free fatty acids were observed with no tachycardia. To assess the anti-diabetic effects of KB-141, ob/ob mice were treated with 0.0547 or 0.328 mg/kg/day KB-141 over 2 weeks. This treatment improved glucose tolerance and insulin sensitivity in a dose-dependent manner while having no effect on heart rate. Therefore, the selective profile for KB-141 in lean rats correlates with its anti-obesity effects without tachycardia. In addition, lipid-lowering and anti-diabetic effects are also observed at anti-obesity doses suggesting that selective TRb activation by KB-141 attenuates these features of the metabolic syndrome with some selectivity relative to tachycardia.

2:45 Glucocorticoid Receptors: Old Targets that Need New Drugs
John Cidlowski, Ph.D., Group Leader, Molecular Endocrinology Group, National Institute of Environmental Health Sciences, National Institutes of Health
Glucocorticoids are necessary for life after birth and regulate numerous homeostatic functions in man, including glucose homeostasis, protein catabolism, skeletal growth, respiratory function, inflammation, development, behavior and apoptosis. They are also one of the most prescribed classes of anti-inflammatory drugs in the world. Our understanding of how one hormone or drug regulates all of these diverse processes is limited, although most of these actions are thought to be mediated via the glucocorticoid receptor, which is a product of a single gene. However, recent studies in our laboratory have shown that multiple glucocorticoid receptor isoforms are produced from one gene via combinations of alternative mRNA splicing and alternative translation initiation. In addition these glucocorticoid receptor isoforms are subject to several post-translational modifications including ubiquitination, phosphorylation and sumoylation which also modulate receptor function. In this lecture, we will show that these GR receptor isoforms regulate specific subsets of genes and selectively regulate distinct cellular functions such as apoptosis. Finally, we will also describe new studies on the human glucocorticoid receptor protein whose expression is associated with various states of glucocorticoid resistance in human inflammatory disease. Specifically we identify a ligand for hGR and demonstrate that this receptor isoform is transcriptionally active in human cells.

3:15 Pro-Inflammatory Actions of Thiazolidinediones (TZDs) in Macrophages: Mechanism and Implications for Human Health
Julie M. Hall, Ph.D., Research Scientist, Pharmacology and Cancer Biology, Duke University Medical Center
It is currently thought that the anti-infl ammatory actions of peroxisome proliferator-activated receptors (PPARs) may explain the protective effect of these receptors in diabetes, atherosclerosis, cancer and other nfl ammatory diseases. However, emerging evidence for proinfl ammatory activities of activated PPARs is concerning in light of new studies that associate PPAR modulators with an increased incidence of both cardiovascular events in humans and the sporadic formation of tumors in rodents. In an attempt to defi ne the role of each PPAR subtype in infl ammation, we made the unexpected observation that human PPARd is a positive regulator of infl ammatory responses in both monocytes and macrophages. Notably, TNFα-stimulated cells administered PPARd agonists express and secrete elevated levels of infl ammatory cytokines. Most surprising, however, was the fi nding that thiazolidinediones (TZDs) and other known PPARγ ligands display different degrees of pro-infl ammatory activities in a PPARγ- and PPARα-independent manner via their ability to augment PPARõ signaling. A series of mechanistic studies revealed that TZDs, at clinically relevant concentrations, bind and activate the transcriptional activity of PPARd. Collectively, these studies suggest that the observed proinfl ammatory and potentially deleterious effects of PPARõ ligands may be mediated through an off-target effect on PPARd. These studies highlight the need for PPAR modulators with increased receptor subtype-specifi city. Furthermore, they suggest that differences in systemic exposure and, consequently, in the activation of PPARγ and PPARõ may explain why TZDs can exhibit both infl ammatory and anti-infl ammatory activities in humans.

3:45 Vitamin D Receptor Modulators for the Treatment of Cardiovascular Disease: New Assignment for an Old Remedy
J. Ruth Wu-Wong, Ph.D., MBA, Chief Scientific Officer, Vidagene
Vitamin D3 is made in the skin after exposure to ultraviolet light, modified in the liver and kidney to form the active hormone, 1.25-dihydroxyvitamin D3 (calcitriol). Calcitriol binds to a nuclear receptor: the vitamin D receptor (VDR). During the past three decades, the VDR field has focused mainly on elucidating its role in the regulation of parathyroid hormone, intestinal calcium/phosphate absorption and bone metabolism. As a result, several of VDR modulators (VDRMs) have been developed for the treatment of psoriasis, osteoporosis, and hyperparathyroidism secondary to chronic kidney disease (CKD). However, VDR has been identified in more than 30 different tissues in the human body. Recent clinical observations show that VDRM therapy is associated with a survival benefit for Stage 5 CKD patients, which is likely due to a decrease in cardiovascular-related mortality. In addition, in the VDR knockout (KO) mice, renin expression and plasma angiotensin II production were increased; levels of ANP (atrial natriuretic peptide) mRNA and circulating ANP were also increased. The animals were hypertensive, and the size of left ventricular cardiomyocyte was markedly increased. Furthermore, thrombomodulin in the aorta, liver, and kidney of the VDR KO mice was down-regulated, while tissue factor mRNA expression was up-regulated, suggesting that VDR may be involved in regulating fibrinolysis and thrombogenesis. Thrombosis is a frequent and important complication of cancer. In a recent clinical trial testing a high dose of calcitriol plus docetaxel vs. docetaxel alone in cancer patients, it was found that the thrombotic events were significantly reduced in the group receiving calcitriol. These observations suggest that VDR modulators may be useful for treating cardiovascular complications in CKD and oncology.

4:15 Network Refreshment Break in the Exhibit Hall

5:20 Progesterone Receptor Modulation of Inflammatory Signaling in Pregnancy and Labor
Carole R. Mendelson, Ph.D., Professor, Biochemistry and Obstetrics & Gynecology; Director, North Texas March of Dimes Birth Defects Center, University of Texas Southwestern Medical Center at Dallas
The mechanisms underlying the initiation of labor have remained unclear. Throughout most of pregnancy, uterine quiescence is maintained by elevated progesterone acting through the progesterone receptor (PR). However, in humans, levels of circulating progesterone and of uterine PR remain increased throughout pregnancy and into labor. This has led us to postulate that spontaneous labor is initiated by a concerted series of events that antagonize the ability of the PR to regulate genes that maintain uterine quiescence. There is increasing evidence that both term and preterm labor in humans are associated with an inflammatory response. In preterm labor, it is likely that intra-amniotic infection provides the stimulus for increased amniotic fluid cytokines, leukocyte migration into the uterus and increased uterine contractility. However, at term the stimulus for the inflammatory response is unknown. We have obtained compelling evidence that the fetal lung produces a key signal for the initiation of labor at term through augmented production of surfactant, a lipoprotein that is essential for air-breathing. Our findings also suggest that progesterone/PR maintains uterine quiescence throughout most of pregnancy by blocking inflammatory signaling and that the increased inflammatory response near term negatively impacts the capacity of the PR to maintain uterine quiescence, further contributing to the onset of labor.

5:50 Drug Discovery of Selective Progesterone Receptor Modulators
Kristof Chwalisz, M.D., Ph.D., Head, Therapeutic Area, Women’s Health, Clinical Pharmacology and Translational Medicine, TAP Pharmaceuticals Products Inc.
Selective progesterone receptor modulators (SPRMs) represent a new class of progesterone receptor ligands. SPRMs exert clinically relevant tissue-selective progesterone agonist, antagonist, or mixed agonist/antagonist effects on various progesterone target tissues in vivo. New SPRMs with tissue-specific effects, along with recent advances in the understanding of the PR biology and pharmacology, offer the promise of new therapeutic strategies for the treatment of women with symptomatic uterine fibroids, endometriosis-related pain, and abnormal uterine bleeding. Drug discovery approaches of novel SPRMs, with special attention to animal models, will be discussed. 

6:20 Nuclear Receptor Functional Analyses by High-Throughput Imaging
Michael A. Mancini, Ph.D., Associate Professor, Department of Molecular & Cellular Biology, Baylor College of Medicine
Using high-throughput microscopy (HTM), we have developed multiplex single cell models that enable an increasingly integrated view of estrogen (ER) and androgen receptor (AR) functions. In AR studies in HeLa, we have quantified the cytological distribution and transcriptional activity of wild type and mutant ARs in response to 30 compounds (known agonists, antagonists or endocrine disruptors). EC50 values for nuclear translocation and subnuclear speckling were markedly different, and for agonists, a general (but not universal) correlation between speckling and transcription was observed. Importantly, the link between agonist-induced speckling and transcription was AR expression-level-dependent, demonstrating that speckling, in the absence of expression level monitoring, could be misleading when assaying for transcriptional antagonists. For higher level multiplex analsyses, we developed a stable HeLa cell line containing a visible, multicopy promoter-reporter gene array regulated by ER. HTM was used to quantify array size and reporter gene mRNA in response to agonists and antagonists. Using a panel of antibodies to ER coregulators and multi-channel image analysis, we will discuss “visual ChIP” approaches to define promoter array occupancy that can be linked to chromatin changes and mRNA synthesis. In conclusion, we have developed multiplex single cell assays for rapid characterization of transcription function amendable to mechanistic dissection by high-content screening.

6:50 End of Conference Day

Thursday, October 18

7:30-8:35 am Registration & Morning Coffee

DISCOVERY CHEMISTRY

8:35 Chairperson’s Remarks 
William T. Schrader, Ph.D., Deputy Scientific Director, National Institute of 
Environmental Health Sciences, National Institutes of Health

8:40 Discovery of the Physiological Ligand for the RevErb Orphan Nuclear Hormone Receptors: Implications for Metabolic Diseases
Thomas P. Burris, Ph.D., Professor, Nuclear Receptor Biology Laboratory, Pennington Biomedical Research Center, Louisiana State University 
Rev-erba and rev-erbb are orphan nuclear hormone receptors that have been demonstrated to regulate metabolic function and differentiation in hepatic, adipose and muscle tissue. Additionally, these receptors are known to be key regulators of the circadian rhythm. As thus, the rev-erbs represent unique targets for drug discovery if one could regulate their activity with a ligand. Here, I will describe our discovery of the physiological ligand for rev-erba and rev-erbb. I will also discuss the implications for development of novel therapeutics for metabolic and psychiatiric diseases.

9:10 Selective PPAR gamma Modulators for the Treatment of Type 2 Diabetes
H. Blair Wood, Ph.D., Senior Research Fellow, Basic Chemistry, Merck Research Laboratories
Peroxisomal proliferator-activated receptor (PPAR) gamma is a nuclear receptor that is an attractive target for treatment of Type II Diabetes Mellitus. While PPARγ agonists are effective in ameliorating hyperglycemia in T2DM patients, they are associated with adverse effects. Identifi cation of effi cacious PPAR ligands exhibiting a reduced potential to cause these mechanism-based side effects represents an attractive pharmacologic goal. Therefore, selective PPARγ modulators (SPPARγMs or partial agonists) as opposed to full agonists may be desired ligands for the long-term management of T2DM. Towards this end, a series of structurally novel and potent PPARγ ligands were identified through in vitro screening. Characterization of these leads and a comparison of their profi le to that of full PPARγ agonists will be discussed.

9:40 New Vistas in the Search for a Selective Glucocorticoid Receptor Modulator (SGRM)
Matthew W. Carson, Ph.D., Discovery Chemistry, Eli Lilly and Company

10:10 Networking Coffee Break in the Exhibit Hall

10:55 Discovery of Progesterone Receptor Modulators with a Unique Mechanism of Action
Matthew R. Yudt, Ph.D., Women’s Health and Musculoskeletal Biology, Wyeth Research
Progesterone receptor (PR) modulators, both agonists and antagonists, are used in various therapeutic settings. PR agonists are widely used in contraceptives and menopausal hormone therapies while antagonists are available for emergency contraception and have shown clinical efficacy in reproductive disorders such as endometriosis and uterine fibroids. To date, all marketed PR agonists and clinically evaluated antagonists are steroidal compounds, often with subtle differences in structures, pharmacology and mechanism of action. At Wyeth, discovery of new PR modulators has focused on non-steroidal structures with improved biological profiles. For example, Tanaproget, a potent, non-steroidal PR agonist with distinct pre-clinical properties, displays some gene selective regulation distinct from other steroidal agonists. An attempt to develop PR isoform selective modulators led to the discovery of non-steroidal selective PR modulators (SPRM) with unique gene activation and peptide interaction profiles. The challenge remains to use these gene regulation and peptide interaction profiles to predict and screen for biologically improved compound profiles. Finally, we have developed potent nonsteroidal PR antagonists with a novel mechanism of action. Although crystallographic and protease digestion studies indicate an agonist-like conformation for these compounds, they neither induce the strong co-activator peptide interactions that full agonists do, nor do they recruit co-repressor peptides like RU-486 and asoprisnil do. These antagonists appear to function by affecting nuclear translocation and accumulation, and receptor phosphorylation. In summary, Wyeth has found a broad spectrum of PR modulators – from potent complete agonists to antagonists with a unique mechanism of action, to tissue and species-specific compounds, and partial agonists with unique molecular profiles that together highlight the promising diversity of nuclear receptor pharmacology and future drug discovery.

11:25 Tissue Selective Androgen Receptor Modulators 
Lawrence G. Hamann, Ph.D., Discovery Chemistry, Bristol-Myers Squibb, Pharmaceutical Research Institute 
Serum testosterone levels decline with aging in men causing alterations in body composition: diminished energy, muscle strength and physical function. Clinical studies have shown that supplementation of elderly men with physiologic doses of testosterone results in a significant improvement on a number of endpoints, though treatment rates remain low due to concerns about effects on the prostate. Novel therapies using oral Selective Androgen Receptor Modulators (SARMs) have the potential to provide the beneficial effects of androgens with a more favorable side-effect profile. BMS-564929 has been shown to be a potent and orally available SARM with high selectivity for muscle versus prostate. Discussion of structure activity relationships around this clinical lead and genetic markers of androgen action will be described.

11:55 Structure-Activity Relationships of Selective Estrogen Receptor Modulators (SERMs) Optimized for Uterine Antagonism and Ovarian Safety 
Timothy I. Richardson, Ph.D., Principle Research Scientist, Lilly Research
Laboratories - Eli Lilly and Company
Uterine fibroids are non-cancerous growths that develop in the myometrium of the uterus. In some women, they cause abnormal menstrual bleeding that has a profoundly negative effect on quality of life. Hysterectomy is the most definitive solution; however, this surgical procedure is unacceptable for pre-menopausal women desiring future pregnancies. Current pharmaceutical treatments include GnRH agonists, which induce a hypo-estrogenic state and result in fibroid reduction but also cause unacceptable side effects with chronic treatment. Since uterine fibroids exhibit estrogen dependence, the estrogen receptors (ERaα and ERβ) are viable targets. SERMs have ER antagonist or agonist activity depending on the tissue target. Clinical trials have been conducted with the SERM raloxifene to study fibroid reduction. However, its use in pre-menopausal women is limited presumably because it acts as an antagonist in the hypothalamus, resulting in overproduction of gonadotropins and unacceptable ovarian stimulation. Here we describe the development of SERMs that have antagonistic effects in an immature rat uterine model, but in a mature female rat do not significantly raise estrogen levels, a sensitive biomarker for ovarian stimulation. To decrease activity in the hypothalamus, we replaced the pendant phenolic ring common to many SERMs with aryl substituents possessing high polar surface areas thereby reducing brain exposure. Compounds with lower brain/plasma ratios did not significantly raise plasma estrogen levels in mature female rats at pharmacologic doses. This strategy allowed us to select compounds for clinical evaluation.

12:25 pm Luncheon Workshop (Sponsorship Available) or Lunch on Your Own 

12:55 Session Break

INNOVATIVE TECHNOLOGIES FOR NHR MODULATORS

1:55 Chairperson’s Remarks 
William T. Schrader, Ph.D., Deputy Scientific Director, National Institute of Environmental Health Sciences, National Institutes of Health

2:00 Mechanistic Studies of Nuclear Receptor Modulation
Pat Griffin, Ph.D., Professor and Chair, Molecular Therapeutics and Director, Translational Research, The Scripps Research Institute, Scripps Florida
Nuclear receptors are ligand-dependent transcription factors and mediators of metabolism and development. The lipid-sensing receptors have been implicated in metabolic disorders and have been shown to function as heterodimers with the retinoid X receptor associating with promoter regions on target genes. Upon ligand interaction, structural perturbations drive recruitment of cofactors that have intrinsic chromatin remodeling activity that promotes recruitment of basal transcription machinery (e.g., RNA Polymerase II). Detailed analysis of the mechanism of activation of these receptors and the signaling pathway requires a multi-pronged approach. Using the Peroxisome proliferator-activated receptor as a model we employed small molecules, cell-based assays, proteomics, RNA dynamics and structural biology to develop an understanding of the relationship between ligand, cofactor recruitment, and transcriptional output. Results from these studies will be presented.

3:00 Networking Refreshment Break in the Exhibit Hall

3:40 Target Specific Virtual Screening for the Estrogen Receptor 
David Lloyd, Ph.D., Molecular Design Group, School of Biochemistry and Immunology, Trinity College Dublin
To date, no truly generic virtual screening (VS) platform exists to produce high hit retrieval rates across numerous targets, indeed a tendency towards delivery of generic screening tools has negatively impacted on the perceived robustness of virtual screening as a discovery tool. Selecting the most appropriate docking tool that will produce the best result for a given target is not straightforward. Here we discuss the development, refinement and reduction to practice of a virtual screening discovery research tool for the human estrogen receptor.

4:40 Panel Discussion

5:10 Close of Nuclear Hormone Receptor Modulators Conference