Synthesis, activity, metabolic stability, and pharmacokinetics of glucocorticoid receptor modulator–statin hybrids

Undesired versus designed enzymatic cleavage of linkers for liver targeting

A design for the selective release of drug molecules in the liver was tested, involving the attachment of a representative active agent by an ester linkage to various 2-substituted 5-aminovaleric acid carbamates. The anticipated pathway of carboxylesterase-1-mediated carbamate cleavage followed by lactamization and drug release was frustrated by unexpectedly high sensitivity of the ester linkage toward hydrolysis by carboxylesterase-2 and other microsomal components.

ATP-dependent transport of statins by human and rat MRP2/Mrp2

Multidrug resistance associated protein-2, MRP2 (human), Mrp2 (rat) are an efflux transporter, responsible for the transport of numerous endogenous and xenobiotic compounds including taurocholate, methotrexate and carboxydichlorofluorescein (CDF). The present study aims to characterise transport of statins by human and rat MRP2/Mrp2 using membrane and vesicle preparations. All statins tested (simvastatin, pravastatin, pitavastatin, fluvastatin, atorvastatin, lovastatin and rosuvastatin) stimulated vanadate-sensitive ATPase activity in membranes expressing human or rat MRP2/Mrp2, suggesting that all statins are substrates of human and rat MRP2/Mrp2. The substrate affinity (Km) of all statins for MRP2/Mrp2 was comparable and no correlation between lipophilicity (logD7.0) and Km was seen. All statins also inhibited uptake of the fluorescent Mrp2 substrate, CDF (1μM) into vesicles expressing human or rat MRP2/Mrp2 with similar IC50 values. Fitting of the inhibitory data to the hill slope equation, gave hill coefficients (h) of greater than one, suggesting that transport involved more than one binding site for inhibitors of MPR2 and Mrp2. We conclude that statins were transported by both human and rat MRP2/Mrp2 with similar affinity. Statins were also shown to compete with other substrates for transport by MRP2/Mrp2 and that this transport involved more than one binding site on the Mrp2/MRP2 protein.

Structure guided design of 5-arylindazole glucocorticoid receptor agonists and antagonists

Glucocorticoid receptor (GR) agonists have been used for more than half a century as the most effective treatment of acute and chronic inflammatory conditions despite serious side effects that accompany their extended use that include glucose intolerance, muscle wasting, skin thinning, and osteoporosis. As a starting point for the identification of GR ligands with an improved therapeutic index, we wished to discover selective nonsteroidal GR agonists and antagonists with simplified structure compared to known GR ligands to serve as starting points for the optimization of dissociated GR modulators. To do so, we selected multiple chemical series by structure guided docking studies and evaluated GR agonist activity. From these efforts we identified 5-arylindazole compounds that showed moderate binding to the glucocorticoid receptor (GR) with clear opportunities for further development. Structure guided optimization was used to design arrays that led to potent GR agonists and antagonists. Several in vitro and in vivo experiments were utilized to demonstrate that GR agonist 23a (GSK9027) had a profile similar to that of a classical steroidal GR agonist.

Discovery of nonsteroidal glucocorticoid receptor ligands based on 6-indole-1,2,3,4-tetrahydroquinolines

A series of nonsteroidal glucocorticoid receptor (GR) ligands based on a 6-indole-1,2,3,4-tetrahydroquinoline scaffold are reported. Structure-activity relationship (SAR) of the pendent indole group identified compound 20 exhibiting good GR binding affinity (K(i)=1.5nM) and 100- to 1000-fold selectivity over MR, PR, and AR while showing activity in an E-selectin repression assay.

5(Z)-Benzylidene-1,2-dihydro-9-hydroxy-10-methoxy-2,2,4-trimethyl-5H-1-aza-6-oxa-chrysenes as non-steroidal glucocorticoid receptor modulators

A series of 5-benzylidene-1,2-dihydro-2,2,4-trimethyl-5H-1-aza-6-oxa-chrysenes was synthesized and profiled for their ability to act as selective glucocorticoid receptor modulators (SGRMs). The synthesis and structure-activity relationships for this series of compounds are presented.

Non-steroidal glucocorticoid agonists: the discovery of aryl pyrazoles as A-ring mimetics

Starting from an established series of non-steroidal glucocorticoid receptor (GR) agonists, a large array was designed where a metabolically labile benzoxazinone moiety was replaced. Initial hits bound to GR but lacked agonist activity. Following two further iterations, potent GR agonists were discovered with 20D1E1 having NFkappaB agonism pIC(50) 8.8 (103%). Other analogues such as 23D1E1 display a dissociated profile (NFkappaB pIC(50) 8.1 (103%), MMTV pEC(50) 7.02 (36%)). The tetrahydronaphthalene moiety can also be replaced with substituted aryls such as 24E1 and 25E1.

Glucocorticoid receptor antagonists: new tools to investigate disorders characterized by cortisol hypersecretion

Increased cortisol levels have been observed in patients suffering from a number of metabolic and psychiatric disorders. In some of these disorders a causal relationship has been suggested between the increased cortisol secretion and the observed clinical phenomena. Glucocorticoid receptor antagonists which block cortisol effects might have a benefit in both the diagnosis and treatment of these disorders. Selective glucocorticoid receptor antagonists with in vivo potency have not been described thus far, partly due to the similarity between the glucocorticoid and progesterone receptors. In the present studies, we report on three different chemical classes derived from the glucocorticoid/progestagen antagonist RU486. Selected compounds from the classes 11-monoaryl steroids, 11,21-bisaryl steroids and 11-aryl, 16-hydroxy steroids proved to be selective glucocorticoid receptor binders with in vivo antagonistic activity. Most compounds were able to pass the blood-brain barrier. These compounds offer the opportunity to investigate and possibly treat patients with a disturbed hypothalamus-pituitary-adrenal axis without side effects caused by an antiprogestagenic action.

Optimization and metabolic stabilization of a class of nonsteroidal glucocorticoid modulators

The optimization of a series of nonsteroidal glucocorticoid modulators is reported. Potent selective GR ligands that have improved metabolic stability were discovered typified by the subnanomolar acid 12 (GR binding IC(50)=0.6 nM).