2-(2-Aminothiazol-4-yl)pyrrolidine-based tartrate diamides as potent, selective and orally bioavailable TACE inhibitors.

TNF-α converting enzyme (TACE) inhibitors are promising agents to treat inflammatory disorders and cancer. We have investigated novel tartrate diamide TACE inhibitors where the tartrate core binds to zinc in a unique tridentate fashion. Incorporating (R)-2-(2-N-alkylaminothiazol-4-yl)pyrrolidines into the left hand side amide of the tartrate scaffold led to the discovery of potent and selective TACE inhibitors, some of which exhibited good rat oral bioavailability.

Expansion of SAR studies on triaryl bis sulfone cannabinoid CB2 receptor ligands.

We report further expansion of the structure activity relationship (SAR) on the triaryl bis sulfone class of compounds (I), which are potent CB(2) receptor ligands with excellent selectivity over the CB(1) receptor. This study was extended to B ring changes, followed by simultaneous optimization of the A-, B-, and C-rings. Compound 42 has excellent CB(2) potency, selectivity and rat exposure.

Non-aromatic A-ring replacement in the triaryl bis-sulfone CB2 receptor inhibitors.

The triaryl bis-sulfone 1 was modified by converting the aryl A-ring to a piperidine ring. The piperidine ring was further elaborated to a spirocyclopropyl piperidine moiety. The effect on CB2 binding potency, rat calcium channel affinity, and CYP 2C9 inhibition is described.

Biaryl substituted hydantoin compounds as TACE inhibitors.

We disclose further optimization of hydantoin TNF-alpha convertase enzyme (TACE) inhibitors. SAR with respect to the non-prime region of TACE active site was explored. A series of biaryl substituted hydantoin compounds was shown to have sub-nanomolar K(i), good rat PK, and good selectivity versus MMP-1, -2, -3, -7, -9, and -13.

Structure and activity relationships of tartrate-based TACE inhibitors.

The syntheses and structure-activity relationships of the tartrate-based TACE inhibitors are discussed. The optimization of both the prime and non-prime sites led to compounds with picomolar activity. Several analogs demonstrated good rat pharmacokinetics.

The discovery of novel tartrate-based TNF-alpha converting enzyme (TACE) inhibitors.

A novel series of TNF-alpha convertase (TACE) inhibitors which are non-hydroxamate have been discovered. These compounds are bis-amides of L-tartaric acid (tartrate) and coordinate to the active site zinc in a tridentate manner. They are selective for TACE over other MMP's. We report the first X-ray crystal structure for a tartrate-based TACE inhibitor.

Discovery of novel spirocyclopropyl hydroxamate and carboxylate compounds as TACE inhibitors.

We have discovered nanomolar inhibitors of TNF-alpha convertase (TACE) comprised of a novel spirocyclic scaffold and either a carboxylate or hydroxamate zinc binding moiety. X-ray crystal structures and computer models of selected compounds binding to TACE explain the observed SAR. We report the first TACE X-ray crystal structure for an inhibitor with a carboxylate zinc ligand.

Impairment of leukocyte trafficking in a murine pleuritis model by IL-4 and IL-10.

We have characterized leukocyte migration to the pleural cavity in a methylated-BSA (mBSA)-induced model of murine delayed-type hypersensitivity and evaluated the ability of IL-4 and IL-10 to modulate this response. Neutrophils, macrophages, T cells, and dendritic cells migrated to the pleural cavity in a time-dependent fashion following direct intrapleural antigen challenge, with neutrophils comprising the majority of exudate leukocytes in the cavity within the first 24 h and the number of mononuclear cells increasing at later times. Real-time quantitative PCR analysis of infiltrating leukocytes revealed a marked elevation of steady-state mRNA levels of IL-1beta and TNFalpha and the chemokines KC, MIP-2, CXCL9, CXCL10, CXCL11, CCL2, CCL3, and CCL4 at 6 h postchallenge, which diminished over time. In contrast, gammaIFN mRNA levels were maximal at 24 h and CCL5 expression was sustained throughout 72 h. ELISA analysis of pleural exudate fluid revealed significant elevations of KC and CCL2 protein levels at 6 h postantigen challenge and a peak increase in gammaIFN protein at 24 h, confirming our mRNA observations. Administration of recombinant murine IL-4 or IL-10 prior to challenge significantly blocked cell trafficking to the pleural cavity as well as peak levels of exudate gammaIFN, with IL-4 being more potent in impairing these responses. IL-4 administration also increased the proportion of naive T cells in the pleural cavity, as judged by CD62L and CD45RB expression. These results indicate that this in vivo model demonstrates a pattern of events associated with Th1-mediated leukocyte trafficking and underscore the potential utility of this in vivo model for evaluating therapeutic inhibitors of leukocyte trafficking.

Pharmacological characterization of Sch527123, a potent allosteric CXCR1/CXCR2 antagonist.

In neutrophils, growth-related protein-alpha (CXCL1) and interleukin-8 (CXCL8), are potent chemoattractants (Cytokine 14:27-36, 2001; Biochemistry 42:2874-2886, 2003) and can stimulate myeloperoxidase release via activation of the G protein-coupled receptors CXCR1 and CXCR2. The role of CXCR1 and CXCR2 in the pathogenesis of inflammatory responses has encouraged the development of small molecule antagonists for these receptors. The data presented herein describe the pharmacology of 2-hydroxy-N,N-dimethyl-3-{2-[[(R)-1-(5-methyl-furan-2-yl)-propyl]amino]-3,4-dioxo-cyclobut-1-enylamino}-benzamide (Sch527123), a novel antagonist of both CXCR1 and CXCR2. Sch527123 inhibited chemokine binding to (and activation of) these receptors in an insurmountable manner and, as such, is categorized as an allosteric antagonist. Sch527123 inhibited neutrophil chemotaxis and myeloperoxidase release in response to CXCL1 and CXCL8 but had no effect on the response of these cells to C5a or formyl-methionyl-leucyl-phenylalanine. The pharmacological specificity of Sch527123 was confirmed by testing in a diversity profile against a panel of enzymes, channels, and receptors. To measure compound affinity, we characterized [(3)H]Sch527123 in both equilibrium and nonequilibrium binding analyses. Sch527123 binding to CXCR1 and CXCR2 was both saturable and reversible. Although Sch527123 bound to CXCR1 with good affinity (K(d) = 3.9 +/- 0.3 nM), the compound is CXCR2-selective (K(d) = 0.049 +/- 0.004 nM). Taken together, our data show that Sch527123 represents a novel, potent, and specific CXCR2 antagonist with potential therapeutic utility in a variety of inflammatory conditions.

Cannabinoid CB(2)-selective inverse agonist protects against antigen-induced bone loss.

Work to improve the therapeutic properties of cannabinoid CB(2) receptor-selective inverse agonists has led to the development of Sch.036, an aryl substituted triaryl bis-sulfone with improved oral pharmacokinetic parameters. In this report, we show that this compound blocks in vivo trafficking of various leukocyte populations, a property consistent with other members of this chemical series. This CB(2)-selective compound also shows efficacy in leukocyte recruitment models when added in concert with suboptimal doses of selected anti-inflammatory agents, consistent with its unique function and indicative of its potential therapeutic utility. Finally, studies with Sch.036 show that this cannabinoid CB(2)-specific inverse agonist can ameliorate bone damage in a rat model of relapsing-remitting arthritis. This result suggests that a cannabinoid CB(2)-selective inverse agonist may help ameliorate a particularly harmful property of this inflammatory joint disease.

A novel cannabinoid peripheral cannabinoid receptor-selective inverse agonist blocks leukocyte recruitment in vivo.

The expression of the cannabinoid peripheral cannabinoid receptor (CB(2)) receptor on peripheral immune cells suggests that compounds specific for CB(2) might be effective anti-inflammatory agents. In this report, we present the initial biological profiling of a novel triaryl bis-sulfone, Sch.336 (N-[1(S)-[4-[[4-methoxy-2-[(4-methoxyphenyl)sulfonyl]phenyl]-sulfonyl]phenyl]ethyl]methanesulfonamide), which is selective for the human cannabinoid CB(2) receptor (hCB(2)). Sch.336 is an inverse agonist at hCB(2), as shown by its ability to decrease guanosine 5'-3-O-(thio)triphosphate (GTPgammaS) binding to membranes containing hCB(2), by the ability of GTPgammaS to left-shift Sch.336 binding to hCB(2) in these membranes, and by the compound's ability to increase forskolin-stimulated cAMP levels in CHO cells expressing hCB(2). In these systems, Sch.336 displays a greater potency than that reported for the CB(2)-selective dihydropyrazole, SR144528 (N-[(1S)-endo-1,3,3-trimethylbicyclo [2.2.1]heptan2-yl]-5-(4-chloro-3-methylphenyl)-1-[(4-methylphenyl)methyl]-1H-pyrazole-3-carboxamide). In vitro, Sch.336 impairs the migration of CB(2)-expressing recombinant cell lines to the cannabinoid agonist 2-arachidonylglycerol. In vivo, the compound impairs migration of cells to cannabinoid agonist HU210 [(6aR)-trans-3-(1,1-dimethylheptyl)-6a,7,10,10a-tetrahydro-1-hydroxy-6,6-dimethyl-6H-dibenzo [b,d] pyran-9-methanol]. Oral administration of the Sch.336 significantly inhibited leukocyte trafficking in several rodent in vivo models, induced either by specific chemokines or by antigen challenge. Finally, oral administration of Sch.336 blocked ovalbumin-induced lung eosinophilia in mice, a disease model for allergic asthma. We conclude that selective cannabinoid CB(2) inverse agonists may serve as novel immunomodulatory agents in the treatment of a broad range of acute and chronic inflammatory disorders in which leukocyte recruitment is a hallmark of disease pathology.

Characterization of peripheral human cannabinoid receptor (hCB2) expression and pharmacology using a novel radioligand, [35S]Sch225336.

Studies to characterize the endogenous expression and pharmacology of peripheral human cannabinoid receptor (hCB2) have been hampered by the dearth of authentic anti-hCB2 antibodies and the lack of radioligands with CB2 selectivity. We recently described a novel CB2 inverse agonist, N-[1(S)-[4-[[4-methoxy-2-[(4methoxyphenyl)sulfonyl] phenyl]sulfonyl] phenyl]ethyl]methane-sulfonamide (Sch225336), that binds hCB2 with high affinity and excellent selectivity versus hCB1. The precursor primary amine of Sch225336 was prepared and reacted directly with [(35)S]mesyl chloride (synthesized from commercially obtained [(35)S]methane sulfonic acid) to generate [(35)S]Sch225336. [(35)S]Sch225336 has high specific activity (>1,400 Ci/mmol) and affinity for hCB2 (65 pm). Using [(35)S]Sch225336, we assayed hemopoietic cells and cell lines to quantitate the expression and pharmacology of hCB2. Lastly, we used [(35)S]Sch225336 for detailed autoradiographic analysis of CB2 in lymphoid tissues. Based on these data, we conclude that [(35)S]Sch225336 represents a unique radioligand for the study of CB2 endogenously expressed in blood cells and tissues.

Triaryl bis-sulfones as a new class of cannabinoid CB2 receptor inhibitors: identification of a lead and initial SAR studies.

A novel class of cannabinoid CB2 receptor ligands is described. These triaryl bis-sulfones are nanomolar inhibitors of the CB2 receptor and show high selectivity over the cannabinoid CB1 receptor. One example of this new class decreases ligand-induced GTPgammaS binding to recombinant CB2 cell membranes, identifying the compound as a CB2-selective inverse agonist.