RESUMEN
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.
Asunto(s)
Enfermedad de Alzheimer/tratamiento farmacológico , Secretasas de la Proteína Precursora del Amiloide/antagonistas & inhibidores , Inhibidores Enzimáticos/farmacología , Sulfonamidas/farmacología , Tiofenos/farmacología , Adolescente , Adulto , Secretasas de la Proteína Precursora del Amiloide/metabolismo , Precursor de Proteína beta-Amiloide/genética , Precursor de Proteína beta-Amiloide/metabolismo , Animales , Unión Competitiva , Células CHO , Línea Celular , Cricetinae , Cricetulus , Perros , Inhibidores Enzimáticos/farmacocinética , Inhibidores Enzimáticos/toxicidad , Miedo/psicología , Femenino , Humanos , Masculino , Ratones , Ratones Transgénicos , Persona de Mediana Edad , Ratas , Ratas Sprague-Dawley , Receptores Notch/fisiología , Transducción de Señal/efectos de los fármacos , Sulfonamidas/farmacocinética , Sulfonamidas/toxicidad , Tiofenos/farmacocinética , Tiofenos/toxicidad , Adulto JovenRESUMEN
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.
Asunto(s)
Enfermedad de Alzheimer/tratamiento farmacológico , Secretasas de la Proteína Precursora del Amiloide/antagonistas & inhibidores , Secretasas de la Proteína Precursora del Amiloide/metabolismo , Compuestos Heterocíclicos/química , Compuestos Heterocíclicos/farmacología , Sulfonamidas/química , Sulfonamidas/farmacología , Péptidos beta-Amiloides/antagonistas & inhibidores , Péptidos beta-Amiloides/metabolismo , Animales , Células CHO , Cricetinae , Cricetulus , Compuestos Heterocíclicos/síntesis química , Humanos , Estructura Molecular , Unión Proteica , Receptores Notch/metabolismo , Relación Estructura-Actividad , Sulfonamidas/síntesis químicaRESUMEN
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.
Asunto(s)
Enfermedad de Alzheimer/tratamiento farmacológico , Secretasas de la Proteína Precursora del Amiloide/antagonistas & inhibidores , Isoleucina/análogos & derivados , Receptor Notch1/metabolismo , Alcoholes , Secretasas de la Proteína Precursora del Amiloide/metabolismo , Precursor de Proteína beta-Amiloide/química , Animales , Diseño de Fármacos , Humanos , Isoleucina/química , Modelos Químicos , Propanolaminas/química , Sulfonamidas/químicaRESUMEN
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.
Asunto(s)
Enfermedad de Alzheimer/tratamiento farmacológico , Secretasas de la Proteína Precursora del Amiloide/antagonistas & inhibidores , Descubrimiento de Drogas , Inhibidores Enzimáticos/farmacología , Receptor Notch1/metabolismo , Sulfonamidas/farmacología , Tiofenos/farmacología , Enfermedad de Alzheimer/enzimología , Secretasas de la Proteína Precursora del Amiloide/metabolismo , Péptidos beta-Amiloides/metabolismo , Animales , Cristalografía por Rayos X , Modelos Animales de Enfermedad , Relación Dosis-Respuesta a Droga , Inhibidores Enzimáticos/síntesis química , Inhibidores Enzimáticos/química , Ratones , Ratones Transgénicos , Modelos Moleculares , Conformación Molecular , Estereoisomerismo , Relación Estructura-Actividad , Sulfonamidas/síntesis química , Sulfonamidas/química , Tiofenos/síntesis química , Tiofenos/químicaRESUMEN
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.
Asunto(s)
Secretasas de la Proteína Precursora del Amiloide/antagonistas & inhibidores , Química Farmacéutica/métodos , Inhibidores Enzimáticos/síntesis química , Inhibidores Enzimáticos/farmacología , Receptores Notch/metabolismo , Enfermedad de Alzheimer/tratamiento farmacológico , Amiloide/química , Secretasas de la Proteína Precursora del Amiloide/química , Carbono/química , Diseño de Fármacos , Evaluación Preclínica de Medicamentos , Humanos , Modelos Químicos , Receptores Notch/antagonistas & inhibidores , Relación Estructura-ActividadRESUMEN
Transgenic mice (Tg2576) overexpressing the Swedish mutation of the human amyloid precursor protein display biochemical, pathological, and behavioral markers consistent with many aspects of Alzheimer's disease, including impaired hippocampal function. Impaired, hippocampal-dependent, contextual fear conditioning (CFC) is observed in mice as young as 20 weeks of age. This impairment can be attenuated after treatment before training with the phosphodiesterase-4 inhibitor rolipram (0.1 mg/kg, i.p.). A rolipram-associated improvement is also observed in the littermate controls, suggesting that the effect of rolipram is independent of beta-amyloid. Acute treatment before training (but not after training or before testing) with the gamma-secretase inhibitor (GSI) N-[N-(3,5-difluorophenacetyl)-l-alanyl]-S-phenylglycine-t-butylester (DAPT), at a dose that reduces brain concentrations of beta-amyloid (100 mg/kg), attenuates the impairment in 20- to 65-week-old Tg2576 mice. Importantly, DAPT had no effect on performance of control littermates. These data are supportive of a role of beta-amyloid in the impairment of CFC in Tg2576 mice. Furthermore, they suggest that acute treatment with GSI may provide improved cognitive functioning as well as disease-modifying effects in Alzheimer's disease.
Asunto(s)
Enfermedad de Alzheimer/metabolismo , Enfermedad de Alzheimer/psicología , Condicionamiento Psicológico/efectos de los fármacos , Endopeptidasas/metabolismo , Inhibidores Enzimáticos/farmacología , Miedo , 3',5'-AMP Cíclico Fosfodiesterasas/antagonistas & inhibidores , Envejecimiento/psicología , Enfermedad de Alzheimer/genética , Secretasas de la Proteína Precursora del Amiloide , Péptidos beta-Amiloides/metabolismo , Precursor de Proteína beta-Amiloide/genética , Precursor de Proteína beta-Amiloide/metabolismo , Animales , Ácido Aspártico Endopeptidasas , Cognición/efectos de los fármacos , Trastornos del Conocimiento/inducido químicamente , Trastornos del Conocimiento/psicología , Fosfodiesterasas de Nucleótidos Cíclicos Tipo 4 , Modelos Animales de Enfermedad , Ratones , Ratones Transgénicos , Mutación , Inhibidores de Fosfodiesterasa/farmacología , Rolipram/farmacología , Triglicéridos/farmacología , Ácido gamma-Aminobutírico/análogos & derivados , Ácido gamma-Aminobutírico/farmacologíaRESUMEN
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.
Asunto(s)
Péptidos beta-Amiloides/antagonistas & inhibidores , Encéfalo/efectos de los fármacos , Endopeptidasas/efectos de los fármacos , Piperidinas/síntesis química , Inhibidores de Proteasas/síntesis química , Enfermedad de Alzheimer/enzimología , Secretasas de la Proteína Precursora del Amiloide , Animales , Encéfalo/metabolismo , Diseño de Fármacos , Endopeptidasas/metabolismo , Modelos Moleculares , Piperidinas/farmacología , Inhibidores de Proteasas/farmacología , Unión Proteica , Relación Estructura-ActividadRESUMEN
A method using reverse phase liquid chromatography-tandem mass spectrometry and cassette administration was developed for in vivo brain and plasma exposure profiling to assist early CNS drug discovery programs. Three to four compounds were grouped in cassettes for dosing and analysis. Compounds in the cassettes were selected to minimize possible analytical interference from each other, as well as from their potential metabolites. In order to improve the confidence of cassette administration, an analogue of the study compounds, with well-established brain penetration data, was included in each cassette as a "biological internal standard". Compounds were administered to rats by intraperitoneal injection and extracted from plasma or brain homogenate by simple protein precipitation. Fast chromatographic separation was achieved by using a short narrow-bore column at a flow rate of 1.0ml/min with a fast gradient. The brain penetration of the compounds was evaluated by comparing their C(max) and AUC values in brain and plasma. This approach rapidly provided early brain penetration and plasma exposure information, thus making more of this data available to teams. Comparing the brain exposures to the EC(50) values (i.e. in vitro potency) of series compounds in the same discovery program provided another dimension of information to select lead compounds for future in vivo assessment. The method described here has been used for providing early brain penetration information in several CNS exploratory and discovery programs.