RESUMEN
Inhibition of mutant B-Raf signaling, through either direct inhibition of the enzyme or inhibition of MEK, the direct substrate of Raf, has been demonstrated preclinically to inhibit tumor growth. Very recently, treatment of B-Raf mutant melanoma patients with a selective B-Raf inhibitor has resulted in promising preliminary evidence of antitumor activity. This article describes the design and optimization of tetrahydronaphthalene-derived compounds as potent inhibitors of the Raf pathway in vitro and in vivo. These compounds possess good pharmacokinetic properties in rodents and inhibit B-Raf mutant tumor growth in mouse xenograft models.
Asunto(s)
Antineoplásicos/síntesis química , Proteínas Proto-Oncogénicas B-raf/antagonistas & inhibidores , Tetrahidronaftalenos/síntesis química , Administración Oral , Animales , Antineoplásicos/química , Antineoplásicos/farmacología , Disponibilidad Biológica , Cristalografía por Rayos X , Diseño de Fármacos , Melanoma Experimental/tratamiento farmacológico , Melanoma Experimental/enzimología , Melanoma Experimental/patología , Ratones , Ratones Desnudos , Modelos Moleculares , Mutación , Proteínas Proto-Oncogénicas B-raf/genética , Estereoisomerismo , Relación Estructura-Actividad , Tetrahidronaftalenos/química , Tetrahidronaftalenos/farmacología , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
Starting from a tripeptide screening hit, a series of dipeptide inhibitors of the proteasome with Thr as the P3 residue has been optimized with the aid of crystal structures in complex with the ß-5/6 active site of y20S. Derivative 25, (ß5 IC(50)=7.4 nM) inhibits only the chymotryptic activity of the proteasome, shows cellular activity against targets in the UPS, and inhibits proliferation.
Asunto(s)
Quimotripsina/antagonistas & inhibidores , Dipéptidos/química , Complejo de la Endopetidasa Proteasomal/metabolismo , Treonina/química , Humanos , Modelos MolecularesRESUMEN
The discovery of novel pyrazoline derivatives as B-Raf (V600E) inhibitors is described in this report. Chemical modification of the pyrazoline scaffold led to the development of SAR and identified potent and selective inhibitors of B-Raf (V600E). Determination of the pharmacokinetic properties of selected inhibitors is also reported.
Asunto(s)
Inhibidores de Proteínas Quinasas/química , Proteínas Proto-Oncogénicas B-raf/antagonistas & inhibidores , Pirazoles/química , Sustitución de Aminoácidos , Sitios de Unión , Simulación por Computador , Evaluación Preclínica de Medicamentos , Inhibidores de Proteínas Quinasas/síntesis química , Inhibidores de Proteínas Quinasas/farmacocinética , Proteínas Proto-Oncogénicas B-raf/genética , Proteínas Proto-Oncogénicas B-raf/metabolismo , Pirazoles/síntesis química , Pirazoles/farmacocinética , Proteínas Recombinantes/antagonistas & inhibidores , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Relación Estructura-ActividadRESUMEN
The mammalian 26S proteasome is a 2500 kDa multi-catalytic complex involved in intracellular protein degradation. We describe the synthesis and properties of a novel series of non-covalent di-peptide inhibitors of the proteasome based [corrected] on a capped tri-peptide that was first identified by high-throughput screening of a library of approx. 350000 compounds for inhibitors of the ubiquitin-proteasome system in cells. We show that these compounds are entirely selective for the beta5 (chymotrypsin-like) site over the beta1 (caspase-like) and beta2 (trypsin-like) sites of the 20S core particle of the proteasome, and over a panel of less closely related proteases. Compound optimization, guided by X-ray crystallography of the liganded 20S core particle, confirmed their non-covalent binding mode and provided a structural basis for their enhanced in vitro and cellular potencies. We demonstrate that such compounds show low nanomolar IC50 values for the human 20S beta5 site in vitro, and that pharmacological inhibition of this site in cells is sufficient to potently inhibit the degradation of a tetra-ubiquitin-luciferase reporter, activation of NFkappaB (nuclear factor kappaB) in response to TNF-alpha (tumour necrosis factor-alpha) and the proliferation of cancer cells. Finally, we identified capped di-peptides that show differential selectivity for the beta5 site of the constitutively expressed proteasome and immunoproteasome in vitro and in B-cell lymphomas. Collectively, these studies describe the synthesis, activity and binding mode of a new series of non-covalent proteasome inhibitors with unprecedented potency and selectivity for the beta5 site, and which can discriminate between the constitutive proteasome and immunoproteasome in vitro and in cells.
Asunto(s)
Oligopéptidos/farmacología , Inhibidores de Proteasas/farmacología , Inhibidores de Proteasoma , Secuencia de Aminoácidos , Sitios de Unión , Ácidos Borónicos/farmacología , Bortezomib , Línea Celular , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Cristalografía por Rayos X , Células HCT116 , Células HT29 , Humanos , Cinética , Luciferasas/genética , Luciferasas/metabolismo , Modelos Moleculares , Datos de Secuencia Molecular , Estructura Molecular , FN-kappa B/genética , FN-kappa B/metabolismo , Oligopéptidos/química , Oligopéptidos/metabolismo , Inhibidores de Proteasas/química , Inhibidores de Proteasas/metabolismo , Complejo de la Endopetidasa Proteasomal/genética , Complejo de la Endopetidasa Proteasomal/metabolismo , Unión Proteica , Estructura Terciaria de Proteína , Subunidades de Proteína/antagonistas & inhibidores , Subunidades de Proteína/genética , Subunidades de Proteína/metabolismo , Pirazinas/farmacología , Interferencia de ARN , Homología de Secuencia de Aminoácido , Ubiquitina/genética , Ubiquitina/metabolismoRESUMEN
A high throughput screen identified N-aroylpyrazoline 1 as a selective inhibitor of the V600E mutant of B-Raf kinase. Parallel synthesis of acyl, aroyl, and sulfonyl derivatives led to the identification of several potent inhibitors in both enzymatic and cellular (pERK) assays such as compound 42.