11β-Hydroxysteroid dehydrogenase type 1 inhibitors as therapeutic agents

Divergent Entry to Walsucochin Nortriterpenoids: Total Syntheses of (±)-Walsucochin A and (±)-Walsucochinoids C-F

Nortriterpenoids isolated from Walsura cochinchinensis have attracted much attention from both synthetic and medicinal chemists, yet only recently have efficient synthetic approaches to any members appeared. Shown here is that the common intermediate with a 6/6/5/6-fused tetracyclic ring nucleus can be converted to walsucochin family members. The first total syntheses of (±)-walsucochin A, (±)-walsucochinoids C-F, and their analogues were achieved in this work.

UFSRAT: Ultra-fast Shape Recognition with Atom Types--the discovery of novel bioactive small molecular scaffolds for FKBP12 and 11βHSD1

MOTIVATION

Using molecular similarity to discover bioactive small molecules with novel chemical scaffolds can be computationally demanding. We describe Ultra-fast Shape Recognition with Atom Types (UFSRAT), an efficient algorithm that considers both the 3D distribution (shape) and electrostatics of atoms to score and retrieve molecules capable of making similar interactions to those of the supplied query.

RESULTS

Computational optimization and pre-calculation of molecular descriptors enables a query molecule to be run against a database containing 3.8 million molecules and results returned in under 10 seconds on modest hardware. UFSRAT has been used in pipelines to identify bioactive molecules for two clinically relevant drug targets; FK506-Binding Protein 12 and 11β-hydroxysteroid dehydrogenase type 1. In the case of FK506-Binding Protein 12, UFSRAT was used as the first step in a structure-based virtual screening pipeline, yielding many actives, of which the most active shows a KD, app of 281 µM and contains a substructure present in the query compound. Success was also achieved running solely the UFSRAT technique to identify new actives for 11β-hydroxysteroid dehydrogenase type 1, for which the most active displays an IC50 of 67 nM in a cell based assay and contains a substructure radically different to the query. This demonstrates the valuable ability of the UFSRAT algorithm to perform scaffold hops.

AVAILABILITY AND IMPLEMENTATION

A web-based implementation of the algorithm is freely available at http://opus.bch.ed.ac.uk/ufsrat/.

Design of pyrazolo-pyrimidines as 11β-HSD1 inhibitors through optimisation of molecular electrostatic potential

Rapid and efficient lead optimisation through quantification of the molecular electrostatic potential using quantum mechanics.

Dammarane-type triterpenoids as 11β-HSD1 inhibitors from Homonoia riparia

An exploration for 11β-HSD1 inhibitors from Homonoia riparia returned eight new dammarane-type triterpenoids, horipenoids A–H (1–8), and a known oleanane-type triterpenoid (9). Their structures were elucidated on the basis of comprehensive analysis of spectroscopic data, and the absolute configuration of horipenoid E (5) was established by single crystal X-ray crystallography. Compounds 1–4 represent a rare class of octanortriterpenoids. Horipenoids C (3) and E (5) showed potent inhibition against mouse 11β-HSD1 with IC50 values of 0.810 ± 0.058 and 0.898 ± 0.215 μM, respectively.

11β-HSD1 inhibitors for the treatment of type 2 diabetes and cardiovascular disease

Inhibition of the enzyme 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) has been proposed as a novel therapeutic target for the treatment of type 2 diabetes mellitus. Over 170 new compounds targeting 11β-HSD1 have been developed. This article reviews the current published literature on compounds that have reached phase II clinical trials in patients with type 2 diabetes, and summarises the preclinical evidence that such agents may be useful for associated conditions, including peripheral vascular disease, coronary artery disease and cognitive decline. In clinical trials, 11β-HSD1 inhibitors have been well tolerated and have improved glycaemic control, lipid profile and blood pressure, and induced modest weight loss. The magnitude of the effects are small relative to other agents, so that further development of 11β-HSD1 inhibitors for the primary therapeutic indication of type 2 diabetes has stalled. Ongoing programmes are focused on additional benefits for cognitive function and other cardiovascular risk factors.

Modulation of 11β-hydroxysteroid dehydrogenase as a strategy to reduce vascular inflammation

Atherosclerosis is a chronic inflammatory disease in which initial vascular damage leads to extensive macrophage and lymphocyte infiltration. Although acutely glucocorticoids suppress inflammation, chronic glucocorticoid excess worsens atherosclerosis, possibly by exacerbating systemic cardiovascular risk factors. However, glucocorticoid action within the lesion may reduce neointimal proliferation and inflammation. Glucocorticoid levels within cells do not necessarily reflect circulating levels due to pre-receptor metabolism by 11β-hydroxysteroid dehydrogenases (11β-HSDs). 11β-HSD2 converts active glucocorticoids into inert 11-keto forms. 11β-HSD1 catalyses the reverse reaction, regenerating active glucocorticoids. 11β-HSD2-deficiency/inhibition causes hypertension, whereas deficiency/inhibition of 11β-HSD1 generates a cardioprotective lipid profile and improves glycemic control. Importantly, 11β-HSD1-deficiency/inhibition is atheroprotective, whereas 11β-HSD2-deficiency accelerates atherosclerosis. These effects are largely independent of systemic risk factors, reflecting modulation of glucocorticoid action and inflammation within the vasculature. Here, we consider whether evidence linking the 11β-HSDs to vascular inflammation suggests these isozymes are potential therapeutic targets in vascular injury and atherosclerosis.

11β-HSD1 inhibitors from Walsura cochinchinensis

A search for inhibitors of 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) from Walsura cochinchinensis yielded 10 new limonoids, cochinchinoids A-J (1-10), and two new triterpenoids, 3-epimesendanin S (11) and cochinchinoid K (12). Their structures were assigned on the basis of spectroscopic data, with the absolute configurations of 1 and 12 being established by X-ray diffraction analysis. Of these compounds, cochinchinoid K (12) displayed inhibitory activity against mouse 11β-HSD1 with an IC50 value of 0.82 μM.

Optimisation of pharmacokinetic properties in a neutral series of 11β-HSD1 inhibitors

11β-HSD1 is increasingly seen as an attractive target for the treatment of type II diabetes and other elements of the metabolic syndrome. In this program of work we describe how a series of neutral 2-thioalkyl-pyridine 11β-HSD1 inhibitors were optimized in terms of their pharmacokinetic properties to give compounds with excellent bioavailability in both rat and dog through a core change to pyrimidine. A potential reactive metabolite issue with 4-thioalkyl-pyrimidines was circumvented by a switch from sulfur to carbon substitution.

Discovery of a potent, selective, and orally bioavailable acidic 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) inhibitor: discovery of 2-[(3S)-1-[5-(cyclohexylcarbamoyl)-6-propylsulfanylpyridin-2-yl]-3-piperidyl]acetic acid (AZD4017)

Inhibition of 11β-HSD1 is an attractive mechanism for the treatment of obesity and other elements of the metabolic syndrome. We report here the discovery of a nicotinic amide derived carboxylic acid class of inhibitors that has good potency, selectivity, and pharmacokinetic characteristics. Compound 11i (AZD4017) is an effective inhibitor of 11β-HSD1 in human adipocytes and exhibits good druglike properties and as a consequence was selected for clinical development.

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.

Crystal structures of 11β-hydroxysteroid dehydrogenase type 1 and their use in drug discovery

Cortisol is synthesized by 11β-hydroxysteroid dehydrogenase type 1, inhibitors of which may treat disease associated with excessive cortisol levels. The crystal structures of 11β-hydroxysteroid dehydrogenase type 1 that have been released may aid drug discovery. The crystal structures have been analyzed in terms of the interactions between the protein and the ligands. Despite a variety of structurally different inhibitors the crystal structures of the proteins are quite similar. However, the differences are significant for drug discovery. The crystal structures can be of use in drug discovery, but care needs to be taken when selecting structures for use in virtual screening and ligand docking.

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.

Modulation of 11beta-hydroxysteroid dehydrogenase type 1 activity by 1,5-substituted 1H-tetrazoles

Inhibitors of 11beta-hydroxysteroid dehydrogenase (11beta-HSD1) show promise as drugs to treat metabolic disease and CNS disorders such as cognitive impairment. A series of 1,5-substituted 1H-tetrazole 11beta-HSD1 inhibitors has been discovered and chemically modified. Compounds are selective for 11beta-HSD1 over 11beta-HSD2 and possess good cellular potency in human and murine 11beta-HSD1 assays. A range of in vitro stabilities are observed in human liver microsome assays.

Diazepane-acetamide derivatives as selective 11beta-hydroxysteroid dehydrogenase type 1 inhibitors

WO2008052638 describes the identification and synthesis of diazepane- acetamide derivatives as a novel class of selective small molecule inhibitors of 11beta-hydroxysteroid dehydrogenase type 1 (11beta-HSD1) for the treatment of metabolic syndrome. The generic structure of the disclosed diazepane-acetamide derivatives offers considerable possibilities for modifications that allow optimizing compound properties. Further studies to assess target selectivity, species-specificity, modulation of tissue-specific functions of 11beta-HSD1 as well as interference with alternative functions of this enzyme are needed to explore the therapeutic potential of these chemicals.

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.

Therapeutic manipulation of glucocorticoid metabolism in cardiovascular disease

The therapeutic potential for manipulation of glucocorticoid metabolism in cardiovascular disease was revolutionized by the recognition that access of glucocorticoids to their receptors is regulated in a tissue-specific manner by the isozymes of 11beta-hydroxysteroid dehydrogenase. Selective inhibitors of 11beta-hydroxysteroid dehydrogenase type 1 have been shown recently to ameliorate cardiovascular risk factors and inhibit the development of atherosclerosis. This article addresses the possibility that inhibition of 11beta-hydroxsteroid dehydrogenase type 1 activity in cells of the cardiovascular system contributes to this beneficial action. The link between glucocorticoids and cardiovascular disease is complex as glucocorticoid excess is linked with increased cardiovascular events but glucocorticoid administration can reduce atherogenesis and restenosis in animal models. There is considerable evidence that glucocorticoids can interact directly with cells of the cardiovascular system to alter their function and structure and the inflammatory response to injury. These actions may be regulated by glucocorticoid and/or mineralocorticoid receptors but are also dependent on the 11beta-hydroxysteroid dehydrogenases which may be expressed in cardiac, vascular (endothelial, smooth muscle) and inflammatory (macrophages, neutrophils) cells. The activity of 11beta-hydroxysteroid dehydrogenases in these cells is dependent upon differentiation state, the action of pro-inflammaotory cytokines and the influence of endogenous inhibitors (oxysterols, bile acids). Further investigations are required to clarify the link between glucocorticoid excess and cardiovascular events and to determine the mechanism through which glucocorticoid treatment inhibits atherosclerosis/restenosis. This will provide greater insights into the potential benefit of selective 11beta-hydroxysteroid dehydrogenase inhibitors in treatment of cardiovascular disease.

Antidiabetic and toxicological evaluations of naringenin in normoglycaemic and NIDDM rat models and its implications on extra-pancreatic glucose regulation

AIM

The present investigation was designed to determine the in vivo antidiabetic effect of naringenin (NG) in normoglycaemic and diabetic rat models through blood glucose (GLU) measurements following acute and subchronic time periods. Possible modes of action of NG were investigated and its acute toxicity determined.

METHODS

Normoglycaemic and non-insulin-dependent diabetes mellitus (NIDDM) rat models were treated for acute and subchronic (5 days) time periods with 50 mg/kg/day of NG. Blood biochemical profiles were determined after 5 days of the treatment in normoglycaemic and NIDDM rats using commercial kits for GLU, triglycerides (TG), total cholesterol (CHOL) and high-density lipoprotein (HDL). In order to elucidate its antidiabetic mode of action, NG was administered intragastrically and an oral glucose tolerance test performed using GLU and sucrose (2 g/kg) as substrates. The inhibitory effect of a single concentration of NG (10 microM) on 11beta-hydroxysteroid dehydrogenase type 1 (11beta-HSD1) activity in vitro was determined. Finally, the preclinical safety and tolerability of NG was determined by toxicological evaluation in mice and rats using Organization for Economic Cooperation and Development (OECD) protocols.

RESULTS

Intragastrically administered NG (50 mg/kg) induced a significant decrease in plasma GLU in normoglycaemic and NIDDM rat models (p < 0.05) following acute and subchronic time periods. After 5 days of administration, NG produced significant diminished blood GLU and TG levels in streptozotocin-nicotinamide-induced diabetic rats. The administration of NG to normal rats significantly increased the levels of TG, CHOL and HDL (p < 0.05). NG (5 and 50 mg/kg) induced a total suppression in the increase of plasma GLU levels after administration of substrates (p < 0.01), but NG did not produce inhibition of alpha-glucosidase activity in vitro. However, NG (10 microM) was shown to inhibit 11beta-HSD1 activity by 39.49% in a cellular enzyme assay. Finally, NG showed a Medium Lethal Dose LD(50) > 5000 mg/kg and ranking at level five based on OECD protocols.

CONCLUSION

Our findings suggest that NG may exert its antidiabetic effect by extra-pancreatic action and by suppressing carbohydrate absorption from intestine, thereby reducing the postprandial increase in blood GLU levels.

Antidiabetic activity of N-(6-substituted-1,3-benzothiazol-2-yl)benzenesulfonamides

N-(6-Substituted-1,3-benzothiazol-2-yl)benzenesulfonamide derivatives 1-8 were synthesized and evaluated for their in vivo antidiabetic activity in a non-insulin-dependent diabetes mellitus rat model. Several compounds synthesized showed significant lowering of plasma glucose level in this model. As a possible mode of action, the compounds were in vitro evaluated as 11beta-hydroxysteroid dehydrogenase type 1 (11beta-HSD1) inhibitors. The most active compounds (3 and 4) were docked into the crystal structure of 11beta-HSD1. Docking results indicate potential hydrogen bond interactions with catalytic amino acid residues.