RESUMEN
Huntington's disease (HD) is caused by an expanded CAG trinucleotide repeat in exon 1 of the huntingtin (HTT) gene. We report the design of a series of HTT pre-mRNA splicing modulators that lower huntingtin (HTT) protein, including the toxic mutant huntingtin (mHTT), by promoting insertion of a pseudoexon containing a premature termination codon at the exon 49-50 junction. The resulting transcript undergoes nonsense-mediated decay, leading to a reduction of HTT mRNA transcripts and protein levels. The starting benzamide core was modified to pyrazine amide and further optimized to give a potent, CNS-penetrant, and orally bioavailable HTT-splicing modulator 27. This compound reduced canonical splicing of the HTT RNA exon 49-50 and demonstrated significant HTT-lowering in both human HD stem cells and mouse BACHD models. Compound 27 is a structurally diverse HTT-splicing modulator that may help understand the mechanism of adverse effects such as peripheral neuropathy associated with branaplam.
RESUMEN
Plasma protein binding and tissue binding are arguably two of the most critical parameters that are measured as part of a drug discovery program since, according to the free drug hypothesis, it is the free drug that is responsible for both efficacy and toxicity. This chapter aims to deconstruct the role of plasma protein and tissue binding in drug discovery programs, and to consider the conclusion made by Pfizer and Genentech/Depomed a decade ago that optimising plasma protein binding as an independent parameter does not significantly influence efficacy. This chapter will also examine how binding metrics are applied in drug discovery programs and explore circumstances where optimising plasma protein or tissue binding can be an effective strategy to deliver a candidate molecule for preclinical development with an early indication of sufficient therapeutic index.
Asunto(s)
Proteínas Sanguíneas , Descubrimiento de Drogas , Proteínas Sanguíneas/metabolismo , Unión ProteicaRESUMEN
Usher syndrome type III (USH3), characterized by progressive deafness, variable balance disorder and blindness, is caused by destabilizing mutations in the gene encoding the clarin-1 (CLRN1) protein. Here we report a new strategy to mitigate hearing loss associated with a common USH3 mutation CLRN1(N48K) that involves cell-based high-throughput screening of small molecules capable of stabilizing CLRN1(N48K), followed by a secondary screening to eliminate general proteasome inhibitors, and finally an iterative process to optimize structure-activity relationships. This resulted in the identification of BioFocus 844 (BF844). To test the efficacy of BF844, we developed a mouse model that mimicked the progressive hearing loss associated with USH3. BF844 effectively attenuated progressive hearing loss and prevented deafness in this model. Because the CLRN1(N48K) mutation causes both hearing and vision loss, BF844 could in principle prevent both sensory deficiencies in patients with USH3. Moreover, the strategy described here could help identify drugs for other protein-destabilizing monogenic disorders.
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Modelos Animales de Enfermedad , Proteínas de la Membrana/antagonistas & inhibidores , Pirazoles/farmacología , Piridazinas/farmacología , Bibliotecas de Moléculas Pequeñas/química , Bibliotecas de Moléculas Pequeñas/uso terapéutico , Síndromes de Usher/tratamiento farmacológico , Animales , Ensayos Analíticos de Alto Rendimiento , Humanos , Proteínas de la Membrana/deficiencia , Proteínas de la Membrana/genética , Proteínas de la Membrana/metabolismo , Ratones , Estructura Molecular , Pirazoles/síntesis química , Pirazoles/química , Pirazoles/uso terapéutico , Piridazinas/síntesis química , Piridazinas/química , Piridazinas/uso terapéutico , Bibliotecas de Moléculas Pequeñas/síntesis química , Bibliotecas de Moléculas Pequeñas/farmacología , Relación Estructura-Actividad , Síndromes de Usher/genéticaRESUMEN
The optimization of a potent and highly selective series of dual mTORC1 and mTORC2 inhibitors is described. An initial focus on improving cellular potency whilst maintaining or improving other key parameters, such as aqueous solubility and margins over hERG IC(50), led to the discovery of the clinical candidate AZD8055 (14). Further optimization, particularly aimed at reducing the rate of metabolism in human hepatocyte incubations, resulted in the discovery of the clinical candidate AZD2014 (21).
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Morfolinas/farmacología , Complejos Multiproteicos/antagonistas & inhibidores , Inhibidores de Proteínas Quinasas/farmacología , Serina-Treonina Quinasas TOR/antagonistas & inhibidores , Benzamidas , Procesos de Crecimiento Celular/efectos de los fármacos , Células Cultivadas , Hepatocitos/efectos de los fármacos , Hepatocitos/enzimología , Hepatocitos/metabolismo , Humanos , Diana Mecanicista del Complejo 1 de la Rapamicina , Diana Mecanicista del Complejo 2 de la Rapamicina , PirimidinasRESUMEN
The mammalian target of rapamycin (mTOR) kinase forms two multiprotein complexes, mTORC1 and mTORC2, which regulate cell growth, cell survival, and autophagy. Allosteric inhibitors of mTORC1, such as rapamycin, have been extensively used to study tumor cell growth, proliferation, and autophagy but have shown only limited clinical utility. Here, we describe AZD8055, a novel ATP-competitive inhibitor of mTOR kinase activity, with an IC50 of 0.8 nmol/L. AZD8055 showed excellent selectivity (approximately 1,000-fold) against all class I phosphatidylinositol 3-kinase (PI3K) isoforms and other members of the PI3K-like kinase family. Furthermore, there was no significant activity against a panel of 260 kinases at concentrations up to 10 micromol/L. AZD8055 inhibits the phosphorylation of mTORC1 substrates p70S6K and 4E-BP1 as well as phosphorylation of the mTORC2 substrate AKT and downstream proteins. The rapamycin-resistant T37/46 phosphorylation sites on 4E-BP1 were fully inhibited by AZD8055, resulting in significant inhibition of cap-dependent translation. In vitro, AZD8055 potently inhibits proliferation and induces autophagy in H838 and A549 cells. In vivo, AZD8055 induces a dose-dependent pharmacodynamic effect on phosphorylated S6 and phosphorylated AKT at plasma concentrations leading to tumor growth inhibition. Notably, AZD8055 results in significant growth inhibition and/or regression in xenografts, representing a broad range of human tumor types. AZD8055 is currently in phase I clinical trials.
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Antineoplásicos/farmacología , Morfolinas/farmacología , Neoplasias Experimentales/tratamiento farmacológico , Proteínas Quinasas/efectos de los fármacos , Transducción de Señal/efectos de los fármacos , Animales , Proliferación Celular/efectos de los fármacos , Femenino , Humanos , Ratones , Ratones Desnudos , Inhibidores de Proteínas Quinasas/farmacología , Proteínas Quinasas/metabolismo , Serina-Treonina Quinasas TOR , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
We describe a novel series of potent inhibitors of the kinase activity of mTOR. The compounds display good selectivity relative to other PI3K-related kinase family members and, in cellular assays, inhibit both mTORC1 and mTORC2 complexes and exhibit good antiproliferative activity.
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Antineoplásicos/química , Diaminas/química , Morfolinas/química , Inhibidores de Proteínas Quinasas/química , Proteínas Quinasas/química , Pirimidinas/química , Antineoplásicos/síntesis química , Antineoplásicos/farmacología , Línea Celular , Diaminas/síntesis química , Diaminas/farmacología , Descubrimiento de Drogas , Humanos , Diana Mecanicista del Complejo 1 de la Rapamicina , Morfolinas/síntesis química , Morfolinas/farmacología , Complejos Multiproteicos , Inhibidores de Proteínas Quinasas/síntesis química , Inhibidores de Proteínas Quinasas/farmacología , Proteínas Quinasas/metabolismo , Proteínas , Pirimidinas/síntesis química , Pirimidinas/farmacología , Relación Estructura-Actividad , Serina-Treonina Quinasas TOR , Factores de Transcripción/antagonistas & inhibidores , Factores de Transcripción/metabolismoRESUMEN
A pharmacophore mapping approach, derived from previous experience of PIKK family enzymes, was used to identify a hit series of selective inhibitors of the mammalian target of rapamycin (mTOR). Subsequent refinement of the SAR around this hit series based on a tri-substituted triazine scaffold has led to the discovery of potent and selective inhibitors of mTOR.
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Antineoplásicos/química , Morfolinas/química , Inhibidores de Proteínas Quinasas/química , Proteínas Quinasas/química , Pirimidinas/química , Triazinas/química , Antineoplásicos/síntesis química , Antineoplásicos/farmacología , Línea Celular Tumoral , Humanos , Morfolinas/síntesis química , Morfolinas/farmacología , Fosfatidilinositol 3-Quinasas/metabolismo , Inhibidores de las Quinasa Fosfoinosítidos-3 , Inhibidores de Proteínas Quinasas/síntesis química , Inhibidores de Proteínas Quinasas/farmacología , Proteínas Quinasas/metabolismo , Pirimidinas/síntesis química , Pirimidinas/farmacología , Relación Estructura-Actividad , Serina-Treonina Quinasas TOR , Triazinas/síntesis química , Triazinas/farmacologíaRESUMEN
The NIBR (Novartis Institutes for BioMedical Research) compound collection enrichment and enhancement project integrates corporate internal combinatorial compound synthesis and external compound acquisition activities in order to build up a comprehensive screening collection for a modern drug discovery organization. The main purpose of the screening collection is to supply the Novartis drug discovery pipeline with hit-to-lead compounds for today's and the future's portfolio of drug discovery programs, and to provide tool compounds for the chemogenomics investigation of novel biological pathways and circuits. As such, it integrates designed focused and diversity-based compound sets from the synthetic and natural paradigms able to cope with druggable and currently deemed undruggable targets and molecular interaction modes. Herein, we will summarize together with new trends published in the literature, scientific challenges faced and key approaches taken at NIBR to match the chemical and biological spaces.
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Diseño de Fármacos , Evaluación Preclínica de Medicamentos/métodos , Genómica/métodos , Animales , Inteligencia Artificial , Técnicas Químicas Combinatorias , Humanos , Biblioteca de PéptidosRESUMEN
A heteroatom-tethered regioselective ring-closing metathesis reaction was used for the C-19 functionalization of 1alpha-hydroxy-5,6-trans-vitamin D(2) analogues. Applications of the reaction to form a range of analogues by manipulation of the tether using both organolithium reagents and Diels-Alder cycloadditions are described.