Blockade of Glucocorticoid Excess at the Tissue Level: Inhibitors of 11β-Hydroxysteroid Dehydrogenase Type 1 as a Therapy for Type 2 Diabetes

11β-Hydroxysteroid Dehydrogenase Type 1 as a Potential Treatment Target in Cardiovascular Diseases

Glucocorticoids (GCs) belong to the group of steroid hormones. Their representative in humans is cortisol. GCs are involved in most physiological processes of the body and play a significant role in important biological processes, including reproduction, growth, immune responses, metabolism, maintenance of water and electrolyte balance, functioning of the central nervous system and the cardiovascular system. The availability of cortisol to the glucocorticoid receptor is locally controlled by the enzyme 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1). Evidence of changes in intracellular GC metabolism in the pathogenesis of obesity, metabolic syndrome (MetS) and cardiovascular complications highlights the role of selective 11β-HSD1 inhibition in the pharmacotherapy of these diseases. This paper discusses the role of 11β-HSD1 in MetS and its cardiovascular complications and the importance of selective inhibition of 11β-HSD1.

Novel 2-(Adamantan-1-ylamino)Thiazol-4(5H)-One Derivatives and Their Inhibitory Activity towards 11β-HSD1-Synthesis, Molecular Docking and In Vitro Studies

A common mechanism in which glucocorticoids participate is suggested in the pathogenesis of such metabolic diseases as obesity, metabolic syndrome, or Cushing’s syndrome. The enzyme involved in the control of the availability of cortisol, the active form of the glucocorticoid for the glucocorticoid receptor, is 11β-HSD1. Inhibition of 11β-HSD1 activity may bring beneficial results for the alleviation of the course of metabolic diseases such as metabolic syndrome, Cushing’s syndrome or type 2 diabetes. In this work, we obtained 10 novel 2-(adamantan-1-ylamino)thiazol-4(5H)-one derivatives containing different substituents at C-5 of thiazole ring and tested their activity towards inhibition of two 11β-HSD isoforms. For most of them, over 50% inhibition of 11β-HSD1 and less than 45% inhibition of 11β-HSD2 activity at the concentration of 10 µM was observed. The binding energies found during docking simulations for 11β-HSD1 correctly reproduced the experimental IC₅₀ values for analyzed compounds. The most active compound 2-(adamantan-1-ylamino)-1-thia-3-azaspiro[4.5]dec-2-en-4-one (3i) inhibits the activity of isoform 1 by 82.82%. This value is comparable to the known inhibitor-carbenoxolone. The IC₅₀ value is twice the value determined by us for carbenoxolone, however inhibition of the enzyme isoform 2 to a lesser extent makes it an excellent material for further tests.

Synthesis of Novel 2-(Isopropylamino)thiazol-4(5H)-one Derivatives and Their Inhibitory Activity of 11β-HSD1 and 11β-HSD2 in Aspect of Carcinogenesis Prevention

Glucocorticoid metabolism at the tissue level is regulated by two isoenzymes 11β-hydroxysteroid dehydrogenase (11β-HSD), which mutually convert biologically active cortisol and inactive cortisone. Recent research is focused on the role of 11β-HSD1 and 11β-HSD2 as autocrine factors of tumor cell proliferation and differentiation. Herein, we report the synthesis of novel 2-(isopropylamino)thiazol-4(5H)-one derivatives and their inhibitory activity for 11β-HSD1 and 11β-HSD2. The derivative containing the spiro system of thiazole and cyclohexane rings shows the highest degree of 11β-HSD1 inhibition (54.53% at 10 µM) and is the most selective inhibitor of this enzyme among the tested compounds. In turn, derivatives containing ethyl and n-propyl group at C-5 of thiazole ring inhibit the activity of 11β-HSD2 to a high degree (47.08 and 54.59% at 10 µM respectively) and are completely selective. Inhibition of the activity of these enzymes may have a significant impact on the process of formation and course of tumors. Therefore, these compounds can be considered as potential pharmaceuticals supporting anti-cancer therapy.

Synthesis of the N-methyl Derivatives of 2-Aminothiazol-4(5H)-one and Their Interactions with 11βHSD1-Molecular Modeling and in Vitro Studies

11β-Hydroxysteroid dehydrogenase type 1 (11β-HSD1) is an enzyme that affects the body's cortisol levels. The inhibition of its activity can be used in the treatment of Cushing's syndrome, metabolic syndrome and type 2 diabetes. In this study, we synthesized new derivatives of 2-(methylamino)thiazol-4(5H)-one and tested their activity towards inhibition of 11β-HSD1 and its isoform - 11β-HSD2. The results were compared with the previously tested allyl derivatives. We found out that methyl derivatives are weaker inhibitors of 11β-HSD1 in comparison to their allyl analogs. Due to significant differences in the activity of the compounds, molecular modeling was performed, which was aimed at comparing the interactions between 11β-HSD1 and ligands differing by substituent at the amine group (allyl vs. methyl). Modeling showed that the absence of the allyl group can lead to the rotation of whole ligand molecule which affects its interaction with the enzyme.

An inhibitor of 11-β hydroxysteroid dehydrogenase type 1 (PF915275) alleviates nonylphenol-induced hyperadrenalism and adiposity in rat and human cells

Background

Nonylphenol (NP) is an environmental endocrine-disrupting chemical (EDC) detected in human cord blood and milk. NP exposure in developmental periods results in hyperadrenalism and increasing 11β-hydroxysteroid dehydrogenase I (11β-HSD1) activity in an adult rat model. Alleviating 11β-HSD1 activity is therefore a logical and common way to treat hyperadrenalism. PF915275 (PF; 4′-cyano-biphenyl-4-sulfonic acid (6-amino-pyridin-2-yl)-amide) is a selective inhibitor for 11β-HSD1. This study aimed to determine whether PF915275 could alleviate the hyperadrenalism induced by NP. In addition to a rat model, the effects of NP and PF915275 were measured in human preadipocytes.

Methods

For the in vivo rat model, female adult rats exposed to NP during the developmental period were divided into two treatment groups, with one receiving oral DMSO solution and the other receiving PF915275 once per day for 4 weeks. After the final treatment, the rats from each group were sacrificed for analysis. For the in vitro human model, human preadipocytes received 2 regimens of NP treatment. One treatment regimen occurred before differentiation (to mimic the sensitive developmental period; P exposure), and the other included continuous exposure from preadipocytes to fully differentiated adipocytes (to mimic the growing and adult periods, respectively; C exposure). Protein and RNA were extracted from rat tissues and the preadipocytes for western blot and real-time PCR analysis.

Results

In the rat model, PF915275 alleviated NP-induced effects by interfering with adipogenesis pathways, including enhancing PPARα expression, decreasing PPARγ expression, and reducing both 11β-HSD1 protein and mRNA expression levels. Additionally, PF915275 reduced the effects of the adrenal corticoid synthesis pathway by reducing StAR expression and 11β-hydroxylase and aldosterone synthase activities. With short-term exposure, NP enhanced PPARγ and FASN mRNA expression levels and reduced PPARα expression, whereas PF915275 alleviated these effects. With C exposure, the NP-induced accumulation of intracellular lipids was reduced by PF915275 treatment, which was mediated by decreased PPARγ mRNA and protein expression levels and increased PPARα protein expression.

Conclusions

The effects of NP and PF915275 treatment in both rat and human cell models are similar. Rats may be an appropriate model to study the effects of NP in humans, especially during the developmental period.

A novel derivatives of thiazol-4(5H)-one and their activity in the inhibition of 11β-hydroxysteroid dehydrogenase type 1

11β-Hydroxysteroid dehydrogenase type 1 (11β-HSD1) is an enzyme that catalyzes the conversion of inactive cortisone into physiologically active cortisol. Inhibiting the activity of this enzyme plays a key role in the treatment of Cushing's syndrome, metabolic syndrome and type 2 diabetes. Therefore, new compounds that are selective inhibitors of this enzyme are constantly being looked for. In this work we present the synthesis of 2-(allylamino)thiazol-4(5H)-one derivatives by the reaction of N-allylthiourea with appropriate α-bromoesters. In the case of using of aliphatic α-bromoesters and α-bromo-β-phenylesters, the reactions were carried out in a basic medium (sodium ethoxide) and the products were isolated with a yield of up to 68%. Derivatives containing spiro systems in which carbon C-5 of the thiazole ring is the linker atom were obtained in the presence of N,N-diisopropylethylamine. Some of the obtained compounds, at a concentration of 10 μM have activity in the inhibition of 11β-HSD1 up to 71%. IC₅₀ value for the most active compound: 2-(allylamino)-1-thia-3-azaspiro[4.5]dec-2-en-4-one is 2.5 µM. With a high degree of 11β-HSD1 inhibition and a relatively large difference in the inhibition of 11β-HSD1 and 11β-HSD2 activity, this compound appears to be promising and should be subjected to further testing.

Optimization of 1,2,4-Triazolopyridines as Inhibitors of Human 11β-Hydroxysteroid Dehydrogenase Type 1 (11β-HSD-1)

Small alkyl groups and spirocyclic-aromatic rings directly attached to the left side and right side of the 1,2,4-triazolopyridines (TZP), respectively, were found to be potent and selective inhibitors of human 11β-hydroxysteroid dehydrogenase-type 1 (11β-HSD-1) enzyme. 3-(1-(4-Chlorophenyl)cyclopropyl)-8-cyclopropyl-[1,2,4]triazolo[4,3-a]pyridine (9f) was identified as a potent inhibitor of the 11β-HSD-1 enzyme with reduced Pregnane-X receptor (PXR) transactivation activity. The binding orientation of this TZP series was revealed by X-ray crystallography structure studies.

The regioselective synthesis of spirooxindolo pyrrolidines and pyrrolizidines via three-component reactions of acrylamides and aroylacrylic acids with isatins and α-amino acids

The regioselective three-component condensation of azomethine ylides derived from isatins and α-amino acids with acrylamides or aroylacrylic acids as dipolarophiles has been realized through a one-pot 1,3-dipolar cycloaddition protocol. Decarboxylation of 2'-aroyl-2-oxo-1,1',2,2',5',6',7',7a'-octahydrospiro[indole-3,3'-pyrrolizine]-1'-carboxylic acids is accompanied by cyclative rearrangement with formation of dihydropyrrolizinyl indolones.

GPR119 agonists: a promising approach for T2DM treatment? A SWOT analysis of GPR119

Ever since its advent as a promising therapeutic target for type 2 diabetes mellitus (T2DM), G-protein-coupled receptor 119 (GPR119) has received much interest from the pharmaceutical industry. This interest peaked in June 2010, when Sanofi-Aventis agreed to pay Metabolex (Cymabay Therapeutics) US$375 million for MBX-2982, which was a representative orally active GPR119 agonist. However, Sanofi-Aventis opted to terminate the deal in May 2011 and another leading GPR119 agonist, GSK1292263, had a loss of efficacy during its clinical trial. In this review, I discuss the pros and cons of GPR119 through a strengths, weaknesses, opportunities, and threats (SWOT) analysis and propose development strategies for the eventual success of a GPR119 agonist development program.

1,1-Dioxo-5,6-dihydro-[4,1,2]oxathiazines, a novel class of 11ß-HSD1 inhibitors for the treatment of diabetes

Racemic cis-1,1-dioxo-5,6-dihydro-[4,1,2]oxathiazine derivative 4a was isolated as an impurity in a sample of a hit from a HTS campaign on 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1). After separation by chiral chromatography the 4a-S, 8a-R enantiomer of compound 4a was identified as the true, potent enzyme inhibitor. The cocrystal structure of 4a with human and murine 11ß-HSD1 revealed the unique binding mode of the oxathiazine series. SAR elucidation and optimization in regard to metabolic stability led to monocyclic tetramethyloxathiazines as exemplified by compound 21g.

Design and synthesis of (R)-1-arylsulfonylpiperidine-2-carboxamides as 11β-hydroxysteroid dehydrogenase type 1 inhibitors

R adamantly beats S: 11β-HSD1 is a target for treating metabolic syndrome. The R isomer 5 was selected as a starting point for optimization and SAR studies. Inhibitor 8 w emerged after several rounds of optimization, showing cross-species inhibition of human and mouse 11β-HSD1. It also displays a good DMPK profile in vitro, and was advanced to PK/PD evaluations in vivo. The results confirmed its dose-dependent activity in mice.

Adamantyl carboxamides and acetamides as potent human 11β-hydroxysteroid dehydrogenase type 1 inhibitors

The modulation of 11β-HSD1 activity with selective inhibitors has beneficial effects on various metabolic disorders including insulin resistance, dyslipidemia and obesity. Here we report the discovery of a series of novel adamantyl carboxamide and acetamide derivatives as selective inhibitors of human 11β-HSD1 in HEK-293 cells transfected with the HSD11B1 gene. Optimization based on an initially identified 11β-HSD1 inhibitor (3) led to the discovery of potent inhibitors with IC(50) values in the 100 nM range. These compounds are also highly selective 11β-HSD1 inhibitors with no activity against 11β-HSD2 and 17β-HSD1. Compound 15 (IC(50)=114 nM) with weak inhibitory activity against the key human cytochrome P450 enzymes and moderate stability in incubation with human liver microsomes is worthy of further development. Importantly, compound 41 (IC(50)=280 nM) provides a new lead that incorporates an adamantyl group surrogate and should enable further series diversification.

Discovery of 3-hydroxy-4-cyano-isoquinolines as novel, potent, and selective inhibitors of human 11β-hydroxydehydrogenase 1 (11β-HSD1)

Derived from the HTS hit 1, a series of hydroxyisoquinolines was discovered as potent and selective 11β-HSD1 inhibitors with good cross species activity. Optimization of substituents at the 1 and 4 positions of the isoquinoline group in addition to the core modifications, with a special focus on enhancing metabolic stability and aqueous solubility, resulted in the identification of several compounds as potent advanced leads.

Adamantyl ethanone pyridyl derivatives: potent and selective inhibitors of human 11β-hydroxysteroid dehydrogenase type 1

Elevated levels of active glucocorticoids have been implicated in the development of several phenotypes of metabolic syndrome, such as type 2 diabetes and obesity. 11β-Hydroxysteroid dehydrogenase type 1 (11β-HSD1) catalyses the intracellular conversion of inactive cortisone to cortisol. Selective 11β-HSD1 inhibitors have shown beneficial effects in various conditions, including diabetes, dyslipidemia and obesity. A series of adamantyl ethanone pyridyl derivatives has been identified, providing potent and selective inhibitors of human 11β-HSD1. Lead compounds display low nanomolar inhibition against human and mouse 11β-HSD1 and are selective for this isoform, with no activity against 11β-HSD2 and 17β-HSD1. Structure-activity relationship studies reveal that an unsubstituted pyridine tethered to an adamantyl ethanone motif through an ether or sulfoxide linker provides a suitable pharmacophore for activity. The most potent inhibitors have IC₅₀ values around 34-48 nM against human 11β-HSD1, display reasonable metabolic stability in human liver microsomes, and weak inhibition of key human CYP450 enzymes.

Current and future drug targets in weight management

Obesity will continue to be one of the leading causes of chronic disease unless the ongoing rise in the prevalence of this condition is reversed. Accumulating morbidity figures and a shortage of effective drugs have generated substantial research activity with several molecular targets being investigated. However, pharmacological modulation of body weight is extremely complex, since it is essentially a battle against one of the strongest human instincts and highly efficient mechanisms of energy uptake and storage. This review provides an overview of the different molecular strategies intended to lower body weight or adipose tissue mass. Weight-loss drugs in development include molecules intended to reduce the absorption of lipids from the GI tract, various ways to limit food intake, and compounds that increase energy expenditure or reduce adipose tissue size. A number of new preparations, including combinations of the existing drugs topiramate plus phentermine, bupropion plus naltrexone, and the selective 5-HT(2C) agonist lorcaserin have recently been filed for approval. Behind these leading candidates are several other potentially promising compounds and combinations currently undergoing phase II and III testing. Some interesting targets further on the horizon are also discussed.

Discovery of adamantyl heterocyclic ketones as potent 11β-hydroxysteroid dehydrogenase type 1 inhibitors

11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) plays a key role in converting intracellular cortisone to physiologically active cortisol, which is implicated in the development of several phenotypes of metabolic syndrome. Inhibition of 11β-HSD1 activity with selective inhibitors has beneficial effects on various conditions, including diabetes, dyslipidemia and obesity, and therefore constitutes a promising strategy to discover novel therapies for metabolic and cardiovascular diseases. A series of novel adamantyl heterocyclic ketones provides potent and selective inhibitors of human 11β-HSD1. Lead compounds display low nanomolar inhibition against human and mouse 11β-HSD1 and are selective with no activity against 11β-HSD2 and 17β-HSD1. Selected potent 11β-HSD1 inhibitors show moderate metabolic stability upon incubation with human liver microsomes and weak inhibition of human CYP450 enzymes.

The glucocorticoid contribution to obesity

Obesity is fast becoming the scourge of our time. It is one of the biggest causes of death and disease in the industrialized world, and affects as many as 32% of adults and 17% of children in the USA, considered one of the world's fattest nations. It can also cost countries billions of dollars per annum in direct and indirect care, latest estimates putting the USA bill for obesity-related costs at $147 billion in 2008. It is becoming clear that the pathophysiology of obesity is vastly more complicated than the simple equation of energy in minus energy out. A combination of genetics, sex, perinatal environment and life-style factors can influence diet and energy metabolism. In this regard, psychological stress can have significant long-term impact upon the propensity to gain and maintain weight. In this review, we will discuss the ability of psychological stress and ultimately glucocorticoids (GCs) to alter appetite regulation and metabolism. We will specifically focus on (i) GC regulation of appetite and adiposity, (ii) the apparent sexual dimorphism in stress effects on obesity and (iii) the ability of early life stress to programme obesity in the long term.

Targeting thermogenesis and related pathways in anti-obesity drug discovery

The health consequences of the obesity epidemic are a huge burden on patients and society. Yet it remains an unmet therapeutic need. Lifestyle or behaviour modification, although desirable, seems to benefit only a few and bariatric surgery is not an option for all and not without risks. Nevertheless, bariatric surgery is currently the gold standard in terms of weight loss therapy and any weight loss agent will be in combination with management of lifestyle modification. Sadly, there is a poor history for the pharmacological treatment of obesity and repeated safety concerns have attracted intense regulatory scrutiny. Indeed, recent market withdrawals leave us with just one agent approved for the long term treatment of obesity and that is only mildly efficacious in terms of weight loss, although it is beneficial in terms of metabolic health. There are two broad pharmacological approaches that can be applied in obesity drug discovery: reduce intake (or absorption) or increase expenditure (thermogenesis) of calories. In this review we will look at the latter approach. We will cover regulatory requirements and the rationale for this approach. We believe that post-obese subjects display abnormal metabolic responses to weight loss that almost inevitably leads to weight regain. We will then explore a number of approaches that potentially increase thermogenesis in humans. The challenge we have is in accumulating enough human data to validate this approach using drugs.

Discovery of adamantyl ethanone derivatives as potent 11beta-hydroxysteroid dehydrogenase type 1 (11beta-HSD1) inhibitors

11Beta-hydroxysteroid dehydrogenases (11beta-HSDs) are key enzymes regulating the pre-receptor metabolism of glucocorticoid hormones. The modulation of 11beta-HSD type 1 activity with selective inhibitors has beneficial effects on various conditions including insulin resistance, dyslipidemia and obesity. Inhibition of tissue-specific glucocorticoid action by regulating 11beta-HSD1 constitutes a promising treatment for metabolic and cardiovascular diseases. A series of novel adamantyl ethanone compounds was identified as potent inhibitors of human 11beta-HSD1. The most active compounds identified (52, 62, 72, 92, 103 and 104) display potent inhibition of 11beta-HSD1 with IC(50) values in the 50-70 nM range. Compound 72 also proved to be metabolically stable when incubated with human liver microsomes. Furthermore, compound 72 showed very weak inhibitory activity for human cytochrome P450 enzymes and is therefore a candidate for in vivo studies. Comparison of the publicly available X-ray crystal structures of human 11beta-HSD1 led to docking studies of the potent compounds, revealing how these molecules may interact with the enzyme and cofactor.

The glucocorticoid-activating enzyme 11beta-hydroxysteroid dehydrogenase type 1 has broad substrate specificity: Physiological and toxicological considerations

The primary function of 11beta-hydroxysteroid dehydrogenase type 1 (11beta-HSD1) is to catalyze the conversion of inactive to active glucocorticoid hormones and to modulate local glucocorticoid-dependent gene expression. Thereby 11beta-HSD1 plays a key role in the regulation of metabolic functions and in the adaptation of the organism to energy requiring situations. Importantly, elevated 11beta-HSD1 activity has been associated with metabolic disorders, and recent investigations with rodent models of obesity and type 2 diabetes provided evidence for beneficial effects of 11beta-HSD1 inhibitors, making this enzyme a promising therapeutic target. Several earlier and recent studies, mainly performed in vitro, revealed a relatively broad substrate spectrum of 11beta-HSD1 and suggested that this enzyme has additional functions in the metabolism of some neurosteroids (7-oxy- and 11-oxyandrogens and -progestins) and 7-oxysterols, as well as in the detoxification of various xenobiotics that contain reactive carbonyl groups. While there are many studies on the effect of inhibitors on cortisone reduction and circulating glucocorticoid levels and on the transcriptional regulation of 11beta-HSD1 in obesity and diabetes, only few address the so-called alternative functions of this enzyme. We review recent progress on the biochemical characterization of 11beta-HSD1, with a focus on cofactor and substrate specificity and on possible alternative functions of this enzyme.

Discovery of cyclicsulfonamide derivatives as 11 beta-hydroxysteroid dehydrogenase 1 inhibitors

A new series of cyclic sulfonamide derivatives was synthesized and evaluated for their ability to inhibit 11beta-HSD1. Cyclic sulfonamides with phenylacetyl substituents at the 2-position showed nanomolar inhibitory activities. Among them, compound 4e exhibited a good in vitro inhibitory activity and selectivity toward human 11beta-HSD2.

11beta-hydroxysteroid dehydrogenase activity in acromegalic patients with normal or impaired carbohydrate metabolism

The 11beta-hydroxysteroid dehydrogenase isoenzymes (11beta-HSD) catalyse the interconversion of cortisol (F) and cortisone (E). Earlier studies demonstrated that growth hormone (GH) and insulin resistance may exert opposite effects on the conversion of E to F by 11beta-HSD type 1. Therefore, in the present study we determined F and E concentrations in 562 plasma samples obtained from acromegalic patients during an active phase (76 patients) and after cure of the disease (68 patients). In addition, we examined whether type 2 diabetes mellitus or impaired glucose tolerance, which are frequently associated with active acromegaly could influence plasma F and E levels in these patients. We found that plasma F concentrations were similar in patients with active acromegaly and in those who were cured with pituitary surgery, irradiation and/or medical therapy (mean+/-S.E., 12.4+/-0.3 and 12.7+/-0.4 microg/dl, respectively). However, plasma E levels were significantly higher in patients with active compared to those with cured acromegaly (2.8+/-0.1 and 2.2+/-0.1 microg/dl, respectively; p<0.001), resulting in a lower F/E ratio in patients with active disease (4.6+/-0.1 vs. 5.9+/-0.2 in the cured group of patients; p<0.001). When the effect of altered carbohydrate homeostasis on plasma F and E was analysed, the results indicated significantly lower plasma E levels and higher F/E ratios in active acromegalic patients with type 2 diabetes mellitus or impaired glucose tolerance compared to those with normal carbohydrate metabolism (E, 2.5+/-0.1 and 3.0+/-0.1 microg/dl, respectively; F/E, 5.1+/-0.2 and 4.4+/-0.1; p<0.001), whereas plasma F concentrations were similar in these two groups (12.1+/-0.4 and 12.6+/-0.3 microg/dl, respectively). These findings indicate that disease activity exerts a significant impact on 11beta-HSD in acromegalic patients, which is further modified with altered carbohydrate homeostasis, frequently present in patients with active disease.

Derivatives of (phenylsulfonamido-methyl)nicotine and (phenylsulfonamido-methyl)thiazole as novel 11beta-hydroxysteroid dehydrogenase type 1 inhibitors: synthesis and biological activities in vitro

AIM

To design and synthese a novel class of 11beta-hydroxysteroid dehydrogenase type 1 (11beta-HSD1) inhibitors, featuring the (phenylsulfonamido-methyl)pyridine and (phenylsulfonamido-methyl)thiazole framework.

METHODS

Our initial lead 4-(phenylsulfonamido-methyl)benzamides were modified. Inhibition of human and mouse 11beta-HSD1 enzymatic activities by the new compounds was determined by a scintillation proximity assay (SPA) using microsomes containing 11beta-HSD1.

RESULTS

Sixteen new compounds (6a-6h, 7a-7h) were designed, synthesized and bioassayed. In dose-response studies, several compounds showed strong inhibitory activities with IC50 values at nanomolar or low nanomolar concentrations. Structure-activity relationships are also discussed with respect to molecular docking results.

CONCLUSION

This study provides two promising new templates for 11beta-HSD1 inhibitors.

11beta-hydroxysteroid dehydrogenase type 1 inhibitors: a review of recent patents

BACKGROUND

The main components of metabolic syndrome (obesity, insulin resistance, hypertension and dyslipidemia) have become prevalent worldwide, and excess glucocorticoid levels have been implicated in patients with these symptoms. 11beta-Hydroxysteroid dehydrogenase type 1 (11beta-HSD1) is an enzyme involved in glucocorticoid regulation through catalysis of the conversion of inactive cortisone to its active form cortisol. Numerous rodent studies have demonstrated the potential use of 11beta-HSD1 inhibitors as treatment for the components of metabolic syndrome and limited clinical data in humans have shown 11beta-HSD1 inhibition to improve glucose levels, insulin sensitivity and lipid profiles. Many organizations have been active in the 11beta-HSD1 academic and patent literature, and two previous articles from this journal have reviewed disclosures through August 2007.

OBJECTIVE

To summarize the recent patent literature and progress in defining the utility of small molecule 11beta-HSD1 inhibitors.

METHODS

This review covers the recent 11beta-HSD1 patent literature and clinical activity ranging from late 2007 through the end of 2008.

RESULTS/CONCLUSION

The exploration of 11beta-HSD1 inhibitors continues, as a number of structural classes have been reported by several pharmaceutical companies over the past 16 months. Current clinical trials will ultimately shed light on the feasibility of 11beta-HSD1 inhibitors as pharmaceutical agents for the various components of metabolic syndrome.

Selective inhibition of 11beta-hydroxysteroid dehydrogenase 1 by 18alpha-glycyrrhetinic acid but not 18beta-glycyrrhetinic acid

Elevated cortisol concentrations have been associated with metabolic diseases such as diabetes type 2 and obesity. 11beta-hydroxysteroid dehydrogenase (11beta-HSD) type 1, catalyzing the conversion of inactive 11-ketoglucocorticoids into their active 11beta-hydroxy forms, plays an important role in the regulation of cortisol levels within specific tissues. The selective inhibition of 11beta-HSD1 is currently considered as promising therapeutic strategy for the treatment of metabolic diseases. In recent years, natural compound-derived drug design has gained considerable interest. 18beta-glycyrrhetinic acid (GA), a metabolite of the natural product glycyrrhizin, is not selective and inhibits both 11beta-HSD1 and 11beta-HSD2. Here, we compare the biological activity of 18beta-GA and its diastereomer 18alpha-GA against the two enzymes in lysates of transfected HEK-293 cells and show that 18alpha-GA selectively inhibits 11beta-HSD1 but not 11beta-HSD2. This is in contrast to 18beta-GA, which preferentially inhibits 11beta-HSD2. Using a pharmacophore model based on the crystal structure of the GA-derivative carbenoxolone in complex with human 11beta-HSD1, we provide an explanation for the differences in the activities of 18alpha-GA and 18beta-GA. This model will be used to design novel selective derivatives of GA.

Discovery and optimization of piperidyl benzamide derivatives as a novel class of 11beta-HSD1 inhibitors

Discovery and optimization of a piperidyl benzamide series of 11beta-HSD1 inhibitors is described. This series was derived from a cyclohexyl benzamide lead structures to address PXR selectivity, high non-specific protein binding, poor solubility, limited in vivo exposure, and in vitro cytotoxicity issues observed with the cyclohexyl benzamide structures. These efforts led to the discovery of piperidyl benzamide 15 which features improved properties over the cyclohexyl benzamide derivatives.

H6PDH interacts directly with 11beta-HSD1: implications for determining the directionality of glucocorticoid catalysis

Tissue specific amplification of glucocorticoid action through NADPH-dependent reduction of inactive glucocorticoid precursors by 11beta-hydroxysteroid dehydrogenase (11beta-HSD1) contributes to the development of visceral obesity, insulin resistance and Type 2 Diabetes. Hexose-6-phosphate dehydrogenase (H6PDH) is believed to supply NADPH for the reductase activity of 11beta-HSD1 in the lumen of the endoplasmic reticulum (ER), where the two enzymes are co-localized. We report here expression and purification of full-length and truncated N-terminal domain (NTD) of H6PDH in a mammalian expression system. Interestingly, both full-length H6PDH and the truncated NTD are secreted into the culture medium in the absence of 11beta-HSD1. Purified full-length H6PDH is a bi-functional enzyme with glucose-6-phosphate dehydrogenase (G6PDH) activity as well as 6-phosphogluconolactonase (6PGL) activity. Using co-immunoprecipitation experiments with purified H6PDH and 11beta-HSD1, and with cell lysates expressing H6PDH and 11beta-HSD1, we observe direct physical interaction between the two enzymes. We also show the modulation of 11beta-HSD1 directionality by H6PDH using overexpression and siRNA knockdown systems. The NTD retains the ability to interact with 11beta-HSD1 physically as well as modulate 11beta-HSD1 directionality indicating that the NTD of H6PDH is sufficient for the regulation of the 11beta-HSD1 activity.