ABSTRACT
The presenilin containing gamma-secretase complex is responsible for the regulated intramembraneous proteolysis of the amyloid precursor protein (APP), the Notch receptor, and a multitude of other substrates. gamma-Secretase catalyzes the final step in the generation of Abeta(40) and Abeta(42) peptides from APP. Amyloid beta-peptides (Abeta peptides) aggregate to form neurotoxic oligomers, senile plaques, and congophilic angiopathy, some of the cardinal pathologies associated with Alzheimer's disease. Although inhibition of this protease acting on APP may result in potentially therapeutic reductions of neurotoxic Abeta peptides, nonselective inhibition of the enzyme may cause severe adverse events as a result of impaired Notch receptor processing. Here, we report the preclinical pharmacological profile of GSI-953 (begacestat), a novel thiophene sulfonamide gamma-secretase inhibitor (GSI) that selectively inhibits cleavage of APP over Notch. This GSI inhibits Abeta production with low nanomolar potency in cellular and cell-free assays of gamma-secretase function, and displaces a tritiated analog of GSI-953 from enriched gamma-secretase enzyme complexes with similar potency. Cellular assays of Notch cleavage reveal that this compound is approximately 16-fold selective for the inhibition of APP cleavage. In the human APP-overexpressing Tg2576 transgenic mouse, treatment with this orally active compound results in a robust reduction in brain, plasma, and cerebral spinal fluid Abeta levels, and a reversal of contextual fear-conditioning deficits that are correlated with Abeta load. In healthy human volunteers, oral administration of a single dose of GSI-953 produces dose-dependent changes in plasma Abeta levels, confirming pharmacodynamic activity of GSI-953 in humans.
Subject(s)
Alzheimer Disease/drug therapy , Amyloid Precursor Protein Secretases/antagonists & inhibitors , Enzyme Inhibitors/pharmacology , Sulfonamides/pharmacology , Thiophenes/pharmacology , Adolescent , Adult , Amyloid Precursor Protein Secretases/metabolism , Amyloid beta-Protein Precursor/genetics , Amyloid beta-Protein Precursor/metabolism , Animals , Binding, Competitive , CHO Cells , Cell Line , Cricetinae , Cricetulus , Dogs , Enzyme Inhibitors/pharmacokinetics , Enzyme Inhibitors/toxicity , Fear/psychology , Female , Humans , Male , Mice , Mice, Transgenic , Middle Aged , Rats , Rats, Sprague-Dawley , Receptors, Notch/physiology , Signal Transduction/drug effects , Sulfonamides/pharmacokinetics , Sulfonamides/toxicity , Thiophenes/pharmacokinetics , Thiophenes/toxicity , Young AdultABSTRACT
gamma-Secretase inhibitors have been shown to reduce the production of beta-amyloid, a component of the plaques that are found in brains of patients with Alzheimer's disease. A novel series of heterocyclic sulfonamide gamma-secretase inhibitors that reduce beta-amyloid levels in cells is reported. Several examples of compounds within this series demonstrate a higher propensity to inhibit the processing of amyloid precursor protein compared to Notch, an alternative gamma-secretase substrate.
Subject(s)
Alzheimer Disease/drug therapy , Amyloid Precursor Protein Secretases/antagonists & inhibitors , Amyloid Precursor Protein Secretases/metabolism , Heterocyclic Compounds/chemistry , Heterocyclic Compounds/pharmacology , Sulfonamides/chemistry , Sulfonamides/pharmacology , Amyloid beta-Peptides/antagonists & inhibitors , Amyloid beta-Peptides/metabolism , Animals , CHO Cells , Cricetinae , Cricetulus , Heterocyclic Compounds/chemical synthesis , Humans , Molecular Structure , Protein Binding , Receptors, Notch/metabolism , Structure-Activity Relationship , Sulfonamides/chemical synthesisABSTRACT
In functional assay assessments using the five muscarinic receptor subtypes, a second generation of muscarinic M(1)-preferring receptor agonists [AC-42 (1), AC-260584 (2), 77-LH-28-1 (3) and LY-593039 (4)] was shown to have higher selectivity for muscarinic M(1) over M(3) receptor as compared to historical agonists [talsaclidine (8), sabcomeline (10), xanomeline (11), WAY-132983 (12), cevimeline (9) and NGX-267 (6)]. Another striking difference of these more recent compounds is their affinities for the dopamine D(2) and 5-HT(2B) receptors. Taken together, these results suggest that the newer compounds may have a greater clinical safety profile, especially with regard to muscarinic M(3) receptor-mediated events, than the historical agonists, but their affinities for other receptors may still compromise their use to validate the therapeutic potential of muscarinic M(1) receptor agonists.
Subject(s)
Muscarinic Agonists/pharmacology , Receptor, Muscarinic M1/agonists , Receptor, Muscarinic M3/agonists , Ligands , Muscarinic Agonists/adverse effects , Protein Binding , Receptor, Serotonin, 5-HT2B/drug effects , Receptor, Serotonin, 5-HT2B/metabolism , Receptors, Dopamine D2/drug effects , Receptors, Dopamine D2/metabolismABSTRACT
Accumulation of beta-amyloid (Abeta), produced by the proteolytic cleavage of amyloid precursor protein (APP) by beta- and gamma-secretase, is widely believed to be associated with Alzheimer's disease (AD). Research around the high-throughput screening hit (S)-4-chlorophenylsulfonyl isoleucinol led to the identification of the Notch-1-sparing (9.5-fold) gamma-secretase inhibitor (S)-N-(5-chlorothiophene-2-sulfonyl)-beta,beta-diethylalaninol 7.b.2 (Abeta(40/42) EC(50)=28 nM), which is efficacious in reduction of Abeta production in vivo.
Subject(s)
Alzheimer Disease/drug therapy , Amyloid Precursor Protein Secretases/antagonists & inhibitors , Isoleucine/analogs & derivatives , Receptor, Notch1/metabolism , Alcohols , Amyloid Precursor Protein Secretases/metabolism , Amyloid beta-Protein Precursor/chemistry , Animals , Drug Design , Humans , Isoleucine/chemistry , Models, Chemical , Propanolamines/chemistry , Sulfonamides/chemistryABSTRACT
SAR on HTS hits 1 and 2 led to the potent, Notch-1-sparing GSI 9, which lowered brain Abeta in Tg2576 mice at 100 mg/kg po. Converting the metabolically labile methyl groups in 9 to trifluoromethyl groups afforded the more stable analogue 10, which had improved in vivo potency. Further side chain modification afforded the potent Notch-1-sparing GSI begacestat (5), which was selected for development for the treatment of Alzheimer's disease.
Subject(s)
Alzheimer Disease/drug therapy , Amyloid Precursor Protein Secretases/antagonists & inhibitors , Drug Discovery , Enzyme Inhibitors/pharmacology , Receptor, Notch1/metabolism , Sulfonamides/pharmacology , Thiophenes/pharmacology , Alzheimer Disease/enzymology , Amyloid Precursor Protein Secretases/metabolism , Amyloid beta-Peptides/metabolism , Animals , Crystallography, X-Ray , Disease Models, Animal , Dose-Response Relationship, Drug , Enzyme Inhibitors/chemical synthesis , Enzyme Inhibitors/chemistry , Mice , Mice, Transgenic , Models, Molecular , Molecular Conformation , Stereoisomerism , Structure-Activity Relationship , Sulfonamides/chemical synthesis , Sulfonamides/chemistry , Thiophenes/chemical synthesis , Thiophenes/chemistryABSTRACT
Using a cell-based assay, we have identified a new series of Notch-sparing gamma-secretase inhibitors from HTS screening leads 2a and 2e. Lead optimization studies led to the discovery of analog 8e with improved gamma-secretase inhibitory potency and Notch-sparing selectivity.
Subject(s)
Amyloid Precursor Protein Secretases/antagonists & inhibitors , Chemistry, Pharmaceutical/methods , Enzyme Inhibitors/chemical synthesis , Enzyme Inhibitors/pharmacology , Receptors, Notch/metabolism , Alzheimer Disease/drug therapy , Amyloid/chemistry , Amyloid Precursor Protein Secretases/chemistry , Carbon/chemistry , Drug Design , Drug Evaluation, Preclinical , Humans , Models, Chemical , Receptors, Notch/antagonists & inhibitors , Structure-Activity RelationshipABSTRACT
Here, we have investigated the in vitro pharmacology of a muscarinic agonist, (3R,4R)-3-(3-hexylsulfanyl-pyrazin-2-yloxy)-1-aza-bicyclo[2.2.1]heptane (WAY-132983), and we demonstrated its activity in several models of pain. WAY-132983 had a similar affinity for the five muscarinic receptors (9.4-29.0 nM); however, in calcium mobilization studies it demonstrated moderate selectivity for M(1) (IC(50) = 6.6 nM; E(max) = 65% of 10 muM carbachol-stimulation) over the M(3) (IC(50) = 23 nM; E(max) = 41%) and M(5) receptors (IC(50) = 300 nM; E(max) = 18%). WAY-132983 also activated the M(4) receptor, fully inhibiting forskolin-induced increase in cAMP levels (IC(50) = 10.5 nM); at the M(2) receptor its potency was reduced by 5-fold (IC(50) = 49.8 nM). In vivo, WAY-132983 demonstrated good systemic bioavailability and high brain penetration (>20-fold over plasma levels). In addition, WAY-1329823 produced potent and efficacious antihyperalgesic and antiallodynic effects in rodent models of chemical irritant, chronic inflammatory, neuropathic, and incisional pain. It is noteworthy that efficacy in these models was observed at doses that did not produce analgesia or ataxia. Furthermore, a series of antagonist studies demonstrated that the in vivo activity of WAY-132983 is mediated through activation of muscarinic receptors primarily through the M(4) receptor. The data presented herein suggest that muscarinic agonists, such as WAY-132983, may have a broad therapeutic efficacy for the treatment of pain.
Subject(s)
Bridged-Ring Compounds/pharmacokinetics , Muscarinic Agonists/pharmacology , Pain/prevention & control , Pyrazines/pharmacokinetics , Animals , Biological Availability , Bridged-Ring Compounds/pharmacology , Chronic Disease , Disease Models, Animal , Inflammation , Inhibitory Concentration 50 , Pyrazines/pharmacology , Rats , Receptors, MuscarinicABSTRACT
Alzheimer's disease (AD) is a debilitating disease widely thought to be associated with the accumulation of beta amyloid (Abeta) in the brain. Inhibition of gamma-secretase, one of the enzymes responsible for Abeta production, may be a useful strategy for the treatment of AD. Described below is a series of gamma-secretase inhibitors designed from a scaffold identified by a ROCS [J. Comput. Chem.1996, 17, 1653] search of the corporate database.
