2008 SARMs Research

Crystallization and preliminary X-ray analysis of the human androgen receptor ligand-binding domain with a coactivator-like peptide and selective androgen receptor modulators.

Thauvin M, Robin-Jagerschmidt C, Nique F, Mollat P, Fleury D, Prangé T.

UMR 8015 CNRS, Université Paris Descartes, 4 Avenue de l’Observatoire, 75006 Paris, France.

The ligand-binding domain of the human androgen receptor has been cloned, overproduced and crystallized in the presence of a coactivator-like 11-mer peptide and two different nonsteroidal ligands. The crystals of the two ternary complexes were isomorphous and belonged to space group P2(1)2(1)2(1), with one molecule in the asymmetric unit. They diffracted to 1.7 and 1.95 A resolution, respectively. Structure determination of these two complexes will help in understanding the mode of binding of selective nonsteroidal androgens versus endogenous steroidal ligands and possibly the origin of their tissue selectivity.

 

Selective androgen receptor modulators in preclinical and clinical development.

Narayanan R, Mohler ML, Bohl CE, Miller DD, Dalton JT.

Preclinical Research and Development, GTx, Inc., Memphis, Tennessee, USA.

Androgen receptor (AR) plays a critical role in the function of several organs including primary and accessory sexual organs, skeletal muscle, and bone, making it a desirable therapeutic target. Selective androgen receptor modulators (SARMs) bind to the AR and demonstrate osteo- and myo-anabolic activity; however, unlike testosterone and other anabolic steroids, these nonsteroidal agents produce less of a growth effect on prostate and other secondary sexual organs. SARMs provide therapeutic opportunities in a variety of diseases, including muscle wasting associated with burns, cancer, or end-stage renal disease, osteoporosis, frailty, and hypogonadism. This review summarizes the current standing of research and development of SARMs, crystallography of AR with SARMs, plausible mechanisms for their action and the potential therapeutic indications for this emerging class of drugs.

 

Effect of B-ring substitution pattern on binding mode of propionamide selective androgen receptor modulators.

Bohl CE, Wu Z, Chen J, Mohler ML, Yang J, Hwang DJ, Mustafa S, Miller DD, Bell CE, Dalton JT.

Division of Pharmaceutics, College of Pharmacy, The Ohio State University, 500 West 12th Avenue, 242 L.M. Parks Hall, Columbus, OH 43210, USA.

Selective androgen receptor modulators (SARMs) are essentially prostate sparing androgens, which provide therapeutic potential in osteoporosis, male hormone replacement, and muscle wasting. Herein we report crystal structures of the androgen receptor (AR) ligand-binding domain (LBD) complexed to a series of potent synthetic nonsteroidal SARMs with a substituted pendant arene referred to as the B-ring. We found that hydrophilic B-ring para-substituted analogs exhibit an additional region of hydrogen bonding not seen with steroidal compounds and that multiple halogen substitutions affect the B-ring conformation and aromatic interactions with Trp741. This information elucidates interactions important for high AR binding affinity and provides new insight for structure-based drug design.

 

Use of an electrochemically synthesised metabolite of a selective androgen receptor modulator for mass spectrometry-based sports drug testing.

Thevis M, Lohmann W, Schrader Y, Kohler M, Bornatsch W, Karst U, Schänzer W.

Center for Preventive Doping Research-Institute of Biochemistry, German Sport University Cologne, Am Sportpark Müngersdorf 6, 50933 Cologne, Germany. thevis@dshs-koeln.de

The elucidation of the metabolism of new therapeutics is a major task for pharmaceutical companies and of great interest for drug testing laboratories. The latter in particular need to determine the presence or absence of drugs or their metabolic products in urine to test for a misuse of these compounds. Commonly, in vitro or animal models are used to mimic the human metabolism and produce potential targets in amounts allowing for method development. An alternative route based on electrochemical reactions of drugs was reported to allow for the generation of selected metabolites. The utility of this approach for doping control purposes was demonstrated with a novel class of anabolic agents termed selective androgen receptor modulators (SARMs). An arylpropionamide- derived drug candidate was subjected to electrochemical “metabolism” and a major phase-I- metabolite, resulting from the elimination of a substituted phenol residue as identified in in vitro experiments, was generated and characterised using liquid chromatography/nuclear magnetic resonance spectroscopy and high resolution/high accuracy mass spectrometry. The metabolite was included in routine doping control procedures based on liquid chromatography/tandem mass spectrometry and has served as a reference compound for 5000 doping control specimens.

 

Screening for two selective androgen receptor modulators using gas chromatography-mass spectrometry in doping control analysis.

Thevis M, Kohler M, Schlörer N, Fusshöller G, Schänzer W.

Center for Preventive Doping Research-Institute of Biochemistry, German Sport University Cologne, Am Sportpark Müngersdorf 6, 50933 Cologne, Germany. thevis@dshs-koeln.de

Selective androgen receptor modulators (SARMs) have become a major field of clinical research enabling the tissue-selective stimulation of androgen receptors. The treatment of debilitating diseases, osteoporosis and frailty are primary goals and promising results have been obtained from clinical trials. However, the potential for misuse of SARMs in sport is great and drug testing methods based on liquid chromatography were established for different classes including arylpropionamide-, 2-quinolinone- and bicyclic hydantoin-derived compounds. As gas chromatography and mass spectrometry (GC-MS) are still important analytical tools in sports drug testing, a method to determine 2-quinolinone- and bicyclic hydantoin-derived SARMs established. Spiked urine samples were subjected to routine doping control protocols including enzymatic hydrolysis, liquid-liquid extraction, concentration and derivatisation to trimethylsilylated analogues followed by GC-MS analysis. The method was validated for the items specificity, lower limit of detection (0.2-10 ng mL(-1)), recovery (83-85%), intraday and interday precision (9-15% and 13-18%, respectively), which demonstrates the suitability of conventional GC-MS systems to determine representatives of an emerging class of compounds in doping control specimens.

 

Doping control analysis of tricyclic tetrahydroquinoline-derived selective androgen receptor modulators using liquid chromatography/electrospray ionization tandem mass spectrometry.

Thevis M, Kohler M, Thomas A, Schlörer N, Schänzer W.

Center for Preventive Doping Research – Institute of Biochemistry, German Sport University Cologne, Carl-Diem Weg 6, 50933 Cologne, Germany. m.thevis@biochem.dshs-koeln.de

Selective androgen receptor modulators represent an emerging class of therapeutics to counteract various diseases such as osteoporosis and muscle wasting. Numerous drug candidates have been developed and investigated including a group that comprises a tricyclic tetrahydroquinoline nucleus such as 2-methyl-2-(8-nitro-3a,4,5,9b-tetrahydro-3H-cyclopenta[c]chinolin-4-yl)propan-1-ol. Due to their novelty and medicinal purpose, these compounds also possess great potential for misuse in sports, and studies on the mass spectrometric behavior of three synthesized model substances and drug candidates were conducted to provide information on typical dissociation pathways following electrospray ionization and collision-induced dissociation. Product ion mass spectra derived from protonated molecules were studied using high resolution/high accuracy orbitrap mass spectrometry, and characteristic fragmentation routes and product ions were elucidated. Major and general findings include the elimination of a hydroxyl radical from [M+H](+), the elimination of the 2-substituted side chain, and the gas-phase rearrangement of the investigated tricyclic tetrahydroquinolines to 6-nitroquinoline yielding a common product ion at m/z 175. Knowledge of these dissociation pathways supports the identification of related substances as well as metabolic products, which is of utmost importance to drug testing laboratories. The compounds were implemented into existing screening procedures, and detection limits (0.2-0.6 ng/mL), recoveries (92-97%), and intraday and interday precision (<22%) were evaluated. Copyright (c) 2008 John Wiley & Sons, Ltd.

 

Mass spectrometry of selective androgen receptor modulators.

Thevis M, Schänzer W.

Institute of Biochemistry, Center for Preventive Doping Research, German Sport University Cologne, Carl-Diem Weg 6, 50933 Cologne, Germany. m.thevis@biochem.dshs-koeln.de

Nonsteroidal selective androgen receptor modulators (SARMs) are an emerging class of drugs for treatment of various diseases including osteoporosis and muscle wasting as well as the correction of age-related functional decline such as muscle strength and power. Several SARMs, which have advanced to preclinical and clinical trials, are composed of diverse chemical structures including arylpropionamide-, bicyclic hydantoin-, quinoline-, and tetrahydroquinoline-derived nuclei. Since January 2008, SARMs have been categorized as anabolic agents and prohibited by the World Anti-Doping Agency (WADA). Suitable detection methods for these low-molecular weight drugs were based on mass spectrometric approaches, which necessitated the elucidation of dissociation pathways in order to characterize and identify the target analytes in doping control samples as well as potential metabolic products and synthetic analogs. Fragmentation patterns of representatives of each category of SARMs after electrospray ionization (ESI) and collision-induced dissociation (CID) as well as electron ionization (EI) are summarized. The complexity and structural heterogeneity of these drugs is a daunting challenge for detection methods. Copyright 2008 John Wiley & Sons, Ltd.

 

A selective androgen receptor modulator with minimal prostate hypertrophic activity restores lean body mass in aged orchidectomized male rats.

Allan G, Sbriscia T, Linton O, Lai MT, Haynes-Johnson D, Bhattacharjee S, Ng R, Sui Z, Lundeen S.

Reproductive Therapeutics, Johnson & Johnson Pharmaceutical Research and Development, L.L.C., 1000 U.S. Route 202 South, Raritan, NJ, USA. gallan4@prdus.jnj.com

Androgens are required for the maintenance of normal sexual activity in adulthood and for enhancing muscle growth and lean body mass in adolescents and adults. Androgen receptor (AR) ligands with tissue selectivity (selective androgen receptor modulators, or SARMs) have potential for treating muscle wasting, hypogonadism of aging, osteoporosis, female sexual dysfunction, and other indications. JNJ-37654032 is a nonsteroidal AR ligand with mixed agonist and antagonist activity in androgen-responsive cell-based assays. It is an orally active SARM with muscle selectivity in orchidectomized rat models. It stimulated growth of the levator ani muscle with ED(50) 0.8 mg/kg, stimulating maximal growth at a dose of 3mg/kg. In contrast, it stimulated ventral prostate growth to 21% of its full size at 3mg/kg. At the same time, JNJ-37654032 reduced prostate weight in intact rats by 47% at 3mg/kg, while having no inhibitory effect on muscle. Using magnetic resonance imaging to monitor body composition, JNJ-37654032 restored about 20% of the lean body mass lost following orchidectomy in aged rats. JNJ-37654032 reduced follicle-stimulating hormone levels in orchidectomized rats and reduced testis size in intact rats. JNJ-37654032 is a potent prostate-sparing SARM with the potential for clinical benefit in muscle-wasting diseases.

 

Discovery of a novel series of nonsteroidal androgen receptor modulators: 5- or 6-oxachrysen-2-ones.

Zhao S, Shen Y, van Oeveren A, Marschke KB, Zhi L.

Discovery Research, Ligand Pharmaceuticals Inc., 10275 Science Center Drive, San Diego, CA 92121, USA. szhao2005@gmail.com

A novel oxachrysenone series (2) of nonsteroidal selective androgen receptor modulators (SARM) was developed based on the 6-aryl-2-quinolinones (1). Synthesis and preliminary SAR results based on in vitro assays are discussed. In the cotransfection assay, lead compound 5d showed AR agonist activity more potent than dihydrotestosterone (DHT), whereas compound 17b was a potent antagonist similar to bicalutamide.

 

Discovery and biological characterization of a novel series of androgen receptor modulators.

Zhou C, Wu G, Feng Y, Li Q, Su H, Mais DE, Zhu Y, Li N, Deng Y, Yang D, Wang MW.

The National Center for Drug Screening and State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China.

BACKGROUND AND PURPOSE: Selective androgen receptor modulators are of great value in the treatment of prostate cancer. The purpose of this study was to provide a preliminary characterization of a new class of non-steroidal androgen receptor modulators discovered in a high-throughput screening campaign. EXPERIMENTAL APPROACH: Competitive receptor binding, luciferase-based reporter methods, cell proliferation and in vivo assays were employed to evaluate an initial set of compounds from chemistry efforts. KEY RESULTS: Forty-nine analogues from the chemistry efforts showed high affinity binding to androgen receptors, agonist and/or antagonist activities in both CV-1 and MDA-MB-453 transfection assays. A proliferation assay in LNCaP cells also exhibited this profile. A representative of these non-steroidal compounds (compound 21) was devoid of activity at other nuclear receptors (oestrogen, progesterone, glucocorticoid and mineralocorticoid receptors) in the CV-1 co-transfection assay. At the same time, in an immature castrated rat model, it behaved as an androgen receptor antagonist against the growth of prostate, seminal vesicles and levator ani induced by exogenous androgen. Separation of compound 21 into its enantiomers showed that nearly all the androgen receptor modulating activity and binding resided in the dextrorotatory compound (23) while the laevorotatory isomer (22) possessed weak or little effect depending on the cell type studied. CONCLUSIONS AND IMPLICATIONS: These non-steroidal compounds may represent a new class of androgen receptor modulators for the treatment of not only prostate cancer but other clinical conditions where androgens and androgen receptors are involved in the pathological processes.

 

Androgenic-anabolic steroids and the Olympic Games.

Fitch KD.

School of Human Movement and Exercise Science, Faculty of Life and Health Sciences, University of Western Australia, Nedlands 6009, Australia. kfitch@cyllene.uwa.edu.au

Androgenic-anabolic steroids (AAS) have been misused by athletes at the Olympic Games, both before and after they were prohibited in sport in 1974. Systematic doping with AAS occurred in the German Democratic Republic (GDR) from 1965 to 1989 which assisted that country to win many medals at Olympic Games, especially in female events. Currently, AAS are the most frequent category of prohibited substances detected in the urine of athletes both globally and at the last two Summer Olympic Games. Scientific confirmation that AAS are effective in enhancing sports performance was difficult because ethical approval was difficult for research involving male subjects taking massive doses of androgens as some athletes and bodybuilders did. Methods to detect AAS have evolved gradually over the past three decades and currently, despite an impressive array of sophisticated analytical equipment and methods, anti-doping authorities and analytical scientists continue to face challenges as have occurred from the use by athletes of designer AAS during the past few years. The future development and use of selective androgen receptor modulators (SARMs) can be anticipated to pose problems in the years ahead. Endocrinologists should be aware that on occasions, replacement testosterone (T) therapy may be authorized in sport as a therapeutic use exemption (TUE) and these circumstances are discussed. 2008, Asian Journal of Andrology, SIMM and SJTU. All rights reserved.

 

Selective androgen receptor modulators based on a series of 7H-[1,4]oxazino[3,2-g]quinolin-7-ones with improved in vivo activity.

Long YO, Higuchi RI, Caferro TR, Lau TL, Wu M, Cummings ML, Martinborough EA, Marschke KB, Chang WY, López FJ, Karanewsky DS, Zhi L.

Discovery Research, Ligand Pharmaceuticals, 10275 Science Center Drive, San Diego, CA 92121, USA.

Modification on a lead series of [1,4]oxazino[3,2-g]quinolin-7-ones at the 2-position led to selective androgen receptor modulators with improved in vivo activity. The most potent analog (-)-33a exhibited full maintenance of levator ani muscle at 3mg/kg and reduced activity on ventral prostate weight in a 2-week orally-dosed and orchidectomized rat maintenance assay.

 

New drugs and methods of doping and manipulation.

Thevis M, Kohler M, Schänzer W.

Center for Preventive Doping Research, Institute of Biochemistry, German Sport University Cologne, Carl-Diem-Weg 6, 50933 Cologne, Germany. m.thevis@biochem.dshs-koeln.de

The issue of doping in sport is multifaceted. New drugs not only with anabolic properties such as selective androgen receptor modulators, synthetic insulins, blood doping with erythropoietins or homologous and autologous blood transfusions but also with sample manipulation have necessitated sensitive, comprehensive and specific detection assays allowing for the identification of cheats. New methods based on mass spectrometry, flow cytometry and immunological techniques have been introduced and improved in the past years to support and enhance the antidoping fight. Although numerous approaches are successful and promising, these methods still have some shortcomings.

 

Pharmacological characterization of AC-262536, a novel selective androgen receptor modulator.

Piu F, Gardell LR, Son T, Schlienger N, Lund BW, Schiffer HH, Vanover KE, Davis RE, Olsson R, Bradley SR.

ACADIA Pharmaceuticals Inc., 3911 Sorrento Valley Boulevard, San Diego, CA 92121, USA. fpiu@acadia-pharm.com

Because of the limitations and liabilities of current testosterone therapies, non-steroidal tissue-selective androgen receptor modulators may provide a clinically meaningful advance in therapy. Using a functional cell-based assay AC-262536 was identified as a potent and selective AR ligand, with partial agonist activity relative to the natural androgen testosterone. A 2-week chronic study in castrated male rats indicated that AC-262536 significantly improves anabolic parameters in these animals, especially in stimulating the growth of the levator ani and in suppressing elevated LH levels. In sharp contrast to testosterone, AC-262536 has weak androgenic effects, as measured by prostate and seminal vesicle weights. Thus, AC-262536 represents a novel class of selective androgen receptor modulators (SARMs) with beneficial anabolic effects.

 

Mass spectrometry of hydantoin-derived selective androgen receptor modulators.

Thevis M, Kohler M, Schlörer N, Kamber M, Kühn A, Linscheid MW, Schänzer W.

Center for Preventive Doping Research, Institute of Biochemistry, German Sport University Cologne, Cologne, Germany. m.thevis@biochem.dshs-koeln.de

N-Aryl-hydroxybicyclohydantoins represent a new class of tissue-selective anabolic agents [selective androgen receptor modulators (SARMs)] and are promising therapeutics as well as drugs prohibited in amateur and professional sport. The dissociation behavior after negative and positive electrospray ionization (ESI) and subsequent collision-induced dissociation (CID) was studied with a drug candidate (BMS 564929) as well as structurally related and isotope-labeled analogs using high resolution/high accuracy orbitrap mass spectrometry. Positive ionization and CID yielded characteristic product ions resulting from the cleavage of the hydantoin structure providing information about the proline-derived nucleus as well as the substituted aryl residue at m/z 96 and 193, respectively. Negative ESI and CID (MS/MS) yielded product ions mainly representing losses of water and CO(2), the latter of which is of particular significance as the hydantoin structure does not contain a carboxyl function. Employing MS(n) experiments with accurate mass determination on six model SARMs, dissociation pathways to characteristic product ions were proposed supporting the identification of these drugs, their metabolites or related compounds in future doping control assays.