RESUMEN
The structure-activity relationship (SAR) of a novel, potent and metabolically stable series of sulfonamide-pyrazoles that attenuate ß-amyloid peptide synthesis via γ-secretase inhibition is detailed herein. Sulfonamide-pyrazoles that are efficacious in reducing the cortical Aßx-40 levels in FVB mice via a single PO dose, as well as sulfonamide-pyrazoles that exhibit selectivity for inhibition of APP versus Notch processing by γ-secretase, are highlighted.
Asunto(s)
Secretasas de la Proteína Precursora del Amiloide/antagonistas & inhibidores , Precursor de Proteína beta-Amiloide/antagonistas & inhibidores , Diseño de Fármacos , Inhibidores Enzimáticos/síntesis química , Inhibidores Enzimáticos/farmacología , Compuestos Heterocíclicos con 3 Anillos/síntesis química , Compuestos Heterocíclicos con 3 Anillos/farmacología , Sulfonamidas/síntesis química , Sulfonamidas/farmacología , Péptidos beta-Amiloides/metabolismo , Animales , Evaluación Preclínica de Medicamentos , Inhibidores Enzimáticos/química , Compuestos Heterocíclicos con 3 Anillos/química , Concentración 50 Inhibidora , Ratones , Ratones Endogámicos , Relación Estructura-Actividad , Sulfonamidas/químicaRESUMEN
Utilizing a pharmacophore hypothesis, previously described gamma-secretase inhibiting HTS hits were evolved into novel tricyclic sulfonamide-pyrazoles, with high in vitro potency, good brain penetration, low metabolic stability, and high clearance.
Asunto(s)
Enfermedad de Alzheimer/tratamiento farmacológico , Secretasas de la Proteína Precursora del Amiloide/antagonistas & inhibidores , Secretasas de la Proteína Precursora del Amiloide/metabolismo , Pirazoles/farmacología , Sulfonamidas/farmacología , Animales , Cristalografía por Rayos X , Humanos , Concentración 50 Inhibidora , Modelos Moleculares , Pirazoles/química , Pirazoles/farmacocinética , Ratas , Ratas Sprague-Dawley , Relación Estructura-Actividad , Sulfonamidas/química , Sulfonamidas/farmacocinéticaRESUMEN
Troglitazone, a thiazolidinedione containing compound, was widely used to treat non-insulin dependent-diabetes. Unfortunately, troglitazone was associated with a sporadic liver toxicity that led to a cessation of its use clinically. Here we show that troglitazone induces a rapid and dose-dependent drop of mitochondrial membrane potential in liver HepG2 cells. The decrease in mitochondrial membrane potential induced by 100 microM troglitazone was completed after 5 min and similar in magnitude to that caused by carbonyl cyanide m-chloro phenylhydrazone. The troglitazone-induced loss of mitochondrial membrane potential preceded changes in cell permeability and cell count. In addition, troglitazone-induced a rise of intracellular calcium, subsequent to the drop in mitochondrial membrane potential, which was blocked by EGTA and the Na+/Ca2+ exchange inhibitor bepridil. Finally, application of 100 microM troglitazone for 24h to HepG2 cells resulted in activation of caspase 3. The results of this study shed light on the molecular mechanisms by which troglitazone can cause cytotoxicity.
Asunto(s)
Cromanos/farmacología , Hipoglucemiantes/farmacología , Mitocondrias Hepáticas/efectos de los fármacos , Tiazolidinedionas/farmacología , Adenosina Trifosfato/metabolismo , Calcio/metabolismo , Caspasa 3 , Caspasas/metabolismo , Recuento de Células , Línea Celular Tumoral , Permeabilidad de la Membrana Celular/efectos de los fármacos , Interpretación Estadística de Datos , Relación Dosis-Respuesta a Droga , Activación Enzimática/efectos de los fármacos , Humanos , Interpretación de Imagen Asistida por Computador , Indicadores y Reactivos , Potenciales de la Membrana/efectos de los fármacos , Microscopía Fluorescente , Fijación del Tejido , TroglitazonaRESUMEN
Herein, we describe our strategy to design metabolically stable γ-secretase inhibitors which are selective for inhibition of Aß generation over Notch. We highlight our synthetic strategy to incorporate diversity and chirality. Compounds 30 (ELND006) and 34 (ELND007) both entered human clinical trials. The in vitro and in vivo characteristics for these two compounds are described. A comparison of inhibition of Aß generation in vivo between 30, 34, Semagacestat 41, Begacestat 42, and Avagacestat 43 in mice is made. 30 lowered Aß in the CSF of healthy human volunteers.
Asunto(s)
Secretasas de la Proteína Precursora del Amiloide/antagonistas & inhibidores , Péptidos beta-Amiloides/antagonistas & inhibidores , Inhibidores Enzimáticos/farmacología , Compuestos Heterocíclicos con 3 Anillos/farmacología , Pirazoles/farmacología , Quinolinas/farmacología , Receptores Notch/antagonistas & inhibidores , Sulfonamidas/farmacología , Secretasas de la Proteína Precursora del Amiloide/metabolismo , Péptidos beta-Amiloides/líquido cefalorraquídeo , Péptidos beta-Amiloides/metabolismo , Animales , Área Bajo la Curva , Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico/genética , Perros , Relación Dosis-Respuesta a Droga , Diseño de Fármacos , Estabilidad de Medicamentos , Inhibidores Enzimáticos/síntesis química , Inhibidores Enzimáticos/farmacocinética , Expresión Génica/efectos de los fármacos , Compuestos Heterocíclicos con 3 Anillos/química , Proteínas de Homeodominio/genética , Humanos , Masculino , Ratones , Microsomas Hepáticos/efectos de los fármacos , Microsomas Hepáticos/metabolismo , Modelos Químicos , Estructura Molecular , Pirazoles/síntesis química , Pirazoles/farmacocinética , Quinolinas/síntesis química , Quinolinas/farmacocinética , ARN Mensajero/genética , ARN Mensajero/metabolismo , Ratas , Ratas Sprague-Dawley , Receptores Notch/metabolismo , Relación Estructura-Actividad , Sulfonamidas/química , Factores de Tiempo , Factor de Transcripción HES-1RESUMEN
INTRODUCTION: Inhibition of gamma-secretase presents a direct target for lowering Aß production in the brain as a therapy for Alzheimer's disease (AD). However, gamma-secretase is known to process multiple substrates in addition to amyloid precursor protein (APP), most notably Notch, which has limited clinical development of inhibitors targeting this enzyme. It has been postulated that APP substrate selective inhibitors of gamma-secretase would be preferable to non-selective inhibitors from a safety perspective for AD therapy. METHODS: In vitro assays monitoring inhibitor potencies at APP γ-site cleavage (equivalent to Aß40), and Notch ε-site cleavage, in conjunction with a single cell assay to simultaneously monitor selectivity for inhibition of Aß production vs. Notch signaling were developed to discover APP selective gamma-secretase inhibitors. In vivo efficacy for acute reduction of brain Aß was determined in the PDAPP transgene model of AD, as well as in wild-type FVB strain mice. In vivo selectivity was determined following seven days x twice per day (b.i.d.) treatment with 15 mg/kg/dose to 1,000 mg/kg/dose ELN475516, and monitoring brain Aß reduction vs. Notch signaling endpoints in periphery. RESULTS: The APP selective gamma-secretase inhibitors ELN318463 and ELN475516 reported here behave as classic gamma-secretase inhibitors, demonstrate 75- to 120-fold selectivity for inhibiting Aß production compared with Notch signaling in cells, and displace an active site directed inhibitor at very high concentrations only in the presence of substrate. ELN318463 demonstrated discordant efficacy for reduction of brain Aß in the PDAPP compared with wild-type FVB, not observed with ELN475516. Improved in vivo safety of ELN475516 was demonstrated in the 7d repeat dose study in wild-type mice, where a 33% reduction of brain Aß was observed in mice terminated three hours post last dose at the lowest dose of inhibitor tested. No overt in-life or post-mortem indications of systemic toxicity, nor RNA and histological end-points indicative of toxicity attributable to inhibition of Notch signaling were observed at any dose tested. CONCLUSIONS: The discordant in vivo activity of ELN318463 suggests that the potency of gamma-secretase inhibitors in AD transgenic mice should be corroborated in wild-type mice. The discovery of ELN475516 demonstrates that it is possible to develop APP selective gamma-secretase inhibitors with potential for treatment for AD.
RESUMEN
The synthesis of a chiral pilocarpine analogue 3 in which the lactone ring is replaced by an oxazolidinone and the bridging methylene group is in the ketone oxidation state has been accomplished. The utility of this compound as a key intermediate for the preparation of more complex structures was demonstrated by its reduction to two alcohol epimers and its reaction with a methylene ylide.
Asunto(s)
Cetonas/química , Pilocarpina , Cromatografía Líquida de Alta Presión , Imidazoles/química , Lactonas/química , Espectrometría de Masas , Estructura Molecular , Oxidación-Reducción , Pilocarpina/análogos & derivados , Pilocarpina/síntesis química , Pilocarpina/química , EstereoisomerismoRESUMEN
Here, we report the identification and characterization of five ortho-quinone inhibitors of PTPalpha. We observed that the potency of these compounds in biochemical assays was markedly enhanced by the presence of DTT. A kinetic analysis suggested that they were functioning as irreversible inhibitors and that the inhibition was targeted to the catalytic site of PTPalpha. The inhibition observed by these compounds was sensitive to superoxide dismutase and catalase, suggesting that reactive oxygen species may be mediators of their inhibition. We observed that in the presence of DTT, these compounds would produce up to 2.5mM hydrogen peroxide (H(2)O(2)). The levels of H(2)O(2) produced were sufficient to completely inactivate PTPalpha. In contrast, without a reducing agent the compounds did not generate H(2)O(2) and showed little activity towards PTPalpha. In addition, these compounds inhibited PTPalpha-dependent cell spreading in NIH 3T3 cells at concentrations that were similar to their activity in biochemical assays. The biological implications of these results are discussed as they support growing evidence that H(2)O(2) is a key regulator of PTPs.