RESUMEN
The discovery of potent, bioavailable small molecule inhibitors of p53-HDM2 PPI led us to investigate subsequent modifications to address a CYP3A4 time-dependent inhibition liability. On the basis of the crystal structure of HDM2 in complex with 2, further functionalization of the solvent exposed area of the molecule that binds to Phe19 pocket were investigated as a strategy to modulate the molecule liphophilicity. Introduction of 2-oxo-nicotinic amide at Phe19 proved a viable strategy in obtaining inhibitors exempt from CYP3A4 time-dependent inhibition liability.
Asunto(s)
Citocromo P-450 CYP3A/metabolismo , Fenilalanina/farmacología , Proteínas Proto-Oncogénicas c-mdm2/antagonistas & inhibidores , Bibliotecas de Moléculas Pequeñas/farmacología , Proteína p53 Supresora de Tumor/antagonistas & inhibidores , Relación Dosis-Respuesta a Droga , Humanos , Estructura Molecular , Fenilalanina/química , Unión Proteica/efectos de los fármacos , Proteínas Proto-Oncogénicas c-mdm2/metabolismo , Bibliotecas de Moléculas Pequeñas/síntesis química , Bibliotecas de Moléculas Pequeñas/química , Relación Estructura-Actividad , Proteína p53 Supresora de Tumor/metabolismoRESUMEN
Imidazo-[1, 2-a]pyrazine 1 is a potent inhibitor of Aurora A and B kinase in vitro and is effective in in vivo tumor models, but has poor oral bioavailbility and is unsuitable for oral dosing. We describe herein our effort to improve oral exposure in this class, resulting ultimately in the identification of a potent Aurora inhibitor 16, which exhibited good drug exposure levels across species upon oral dosing, and showed excellent in vivo efficacy in a mouse xenograft tumor model when dosed orally.
Asunto(s)
Antineoplásicos/uso terapéutico , Aurora Quinasa A/antagonistas & inhibidores , Aurora Quinasa B/antagonistas & inhibidores , Imidazoles/uso terapéutico , Inhibidores de Proteínas Quinasas/uso terapéutico , Pirazinas/uso terapéutico , Administración Oral , Animales , Antineoplásicos/administración & dosificación , Antineoplásicos/síntesis química , Antineoplásicos/farmacocinética , Perros , Células HCT116 , Haplorrinos , Histonas/metabolismo , Humanos , Imidazoles/administración & dosificación , Imidazoles/síntesis química , Imidazoles/farmacocinética , Ratones , Fosforilación , Inhibidores de Proteínas Quinasas/administración & dosificación , Inhibidores de Proteínas Quinasas/síntesis química , Inhibidores de Proteínas Quinasas/farmacocinética , Pirazinas/administración & dosificación , Pirazinas/síntesis química , Pirazinas/farmacocinética , Ratas , Estereoisomerismo , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
A new subseries of substituted piperidines as p53-HDM2 inhibitors exemplified by 21 has been developed from the initial lead 1. Research focused on optimization of a crucial HDM2 Trp23-ligand interaction led to the identification of 2-(trifluoromethyl)thiophene as the preferred moiety. Further investigation of the Leu26 pocket resulted in potent, novel substituted piperidine inhibitors of the HDM2-p53 interaction that demonstrated tumor regression in several human cancer xenograft models in mice. The structure of HDM2 in complex with inhibitors 3, 10, and 21 is described.
RESUMEN
Aurora kinases are cell cycle regulated serine/threonine kinases that have been linked to cancer. Compound 1 was identified as a potent Aurora inhibitor but lacked oral bioavailability. Optimization of 1 led to the discovery of a series of fluoroamine and deuterated analogues, exemplified by compound 25, with an improved pharmacokinetic profile. We found that blocking oxidative metabolism at the benzylic position and decreasing the basicity of the amine are important to obtaining compounds with good biological profiles and oral bioavailability.
Asunto(s)
Antineoplásicos/síntesis química , Flúor , Imidazoles/síntesis química , Proteínas Serina-Treonina Quinasas/antagonistas & inhibidores , Pirazinas/síntesis química , Administración Oral , Animales , Antineoplásicos/farmacocinética , Antineoplásicos/farmacología , Aurora Quinasas , Disponibilidad Biológica , Línea Celular Tumoral , Deuterio , Perros , Ensayos de Selección de Medicamentos Antitumorales , Histonas/metabolismo , Humanos , Imidazoles/farmacocinética , Imidazoles/farmacología , Macaca fascicularis , Ratones , Ratones Desnudos , Trasplante de Neoplasias , Fosforilación , Pirazinas/farmacocinética , Pirazinas/farmacología , Ratas , Ratas Sprague-Dawley , Relación Estructura-Actividad , Trasplante HeterólogoRESUMEN
Our continued effort toward the development of the imidazo[1,2-a]pyrazine scaffold as Aurora kinase inhibitors is described. Bioisosteric approach was applied to optimize the 8-position of the core. Several new potent Aurora A/B dual inhibitors, such as 25k and 25l, were identified.
Asunto(s)
Imidazoles/química , Inhibidores de Proteínas Quinasas/química , Proteínas Serina-Treonina Quinasas/antagonistas & inhibidores , Pirazinas/química , Animales , Aurora Quinasa A , Aurora Quinasas , Evaluación Preclínica de Medicamentos , Imidazoles/síntesis química , Imidazoles/farmacocinética , Inhibidores de Proteínas Quinasas/síntesis química , Inhibidores de Proteínas Quinasas/farmacocinética , Proteínas Serina-Treonina Quinasas/metabolismo , Pirazinas/síntesis química , Pirazinas/farmacocinética , RatasRESUMEN
Hepatitis C (HCV) infection is a global health crisis leading to chronic liver disease. In our efforts towards a second generation HCV NS3 serine protease inhibitor with improved profile, we have undertaken SAR studies in various regions of Boceprevir including P2. Herein, we report the synthesis and structure-activity relationship studies of inhibitors with (S)-1,4-dithia-7-azaspiro[4.4]nonane-8-carboxylic acid 2 as P2 substituent replacing the (1R,2S,5S)-6,6-dimethyl 3-azabicyclo[3.1.0]hexane-2-carboxylic acid. The systematic investigation led to the discovery of highly potent inhibitor 25 (K(i)( *)=7nM, EC(90)=30nM) with improved rat exposure of 2.56microM h.
Asunto(s)
Antivirales/química , Prolina/análogos & derivados , Inhibidores de Proteasas/química , Quinolizinas/química , Compuestos de Azufre/química , Proteínas no Estructurales Virales/antagonistas & inhibidores , Animales , Antivirales/síntesis química , Antivirales/farmacocinética , Sitios de Unión , Simulación por Computador , Humanos , Prolina/síntesis química , Prolina/química , Prolina/farmacocinética , Inhibidores de Proteasas/síntesis química , Inhibidores de Proteasas/farmacocinética , Ratas , Relación Estructura-Actividad , Proteínas no Estructurales Virales/metabolismoRESUMEN
The discovery of C-linked imidazole azaheptapyridine bridgehead FPT inhibitors is described. This novel class of compounds are sub nM FPT enzyme inhibitors with potent cellular inhibitory activities. This series also has reduced hERG activity versus previous N-linked imidazole series. X-ray of compound 10a bound to FTase revealed strong interaction between bridgehead imidazole 3N with catalytic zinc atom.
Asunto(s)
Descubrimiento de Drogas/métodos , Farnesiltransferasa/antagonistas & inhibidores , Imidazoles/química , Piridinas/química , Línea Celular Tumoral , Cristalografía por Rayos X , Farnesiltransferasa/metabolismo , Humanos , Imidazoles/metabolismo , Imidazoles/farmacología , Piridinas/metabolismo , Piridinas/farmacologíaRESUMEN
Inhibition of cyclin-dependent kinases (CDKs) has emerged as an attractive strategy for the development of novel oncology therapeutics. Herein is described the utilization of an in vivo screening approach with integrated efficacy and tolerability parameters to identify candidate CDK inhibitors with a suitable balance of activity and tolerability. This approach has resulted in the identification of SCH 727965, a potent and selective CDK inhibitor that is currently undergoing clinical evaluation.
RESUMEN
The imidazo-[1,2-a]-pyrazine (1) is a dual inhibitor of Aurora kinases A and B with modest cell potency (IC50 = 250 nM) and low solubility (5 µM). Lead optimization guided by the binding mode led to the acyclic amino alcohol 12k (SCH 1473759), which is a picomolar inhibitor of Aurora kinases (TdF K d Aur A = 0.02 nM and Aur B = 0.03 nM) with improved cell potency (phos-HH3 inhibition IC50 = 25 nM) and intrinsic aqueous solubility (11.4 mM). It also demonstrated efficacy and target engagement in human tumor xenograft mouse models.
RESUMEN
Farnesyl protein transferase (FPT) inhibition is an interesting and promising approach to noncytotoxic anticancer therapy. Research in this area has resulted in several orally active compounds that are in clinical trials. Electrospray ionization (ESI) time-of-flight mass spectrometry (TOF-MS) was used for the direct detection of a 95 182 Da pentameric noncovalent complex of alpha/beta subunits of FPT containing Zn, farnesyl pyrophosphate (FPP) and SCH 66336, a compound currently undergoing phase III clinical trials as an anticancer agent. It was noted that the desalting of protein samples was an important factor in the detection of the complex. This study demonstrated that the presence of FPP in the system was necessary for the detection of the FPT-inhibitor complex. No pentameric complex was detected in the spectrum when the experiment was carried out in the absence of the FPP. An indirect approach was also applied to confirm the noncovalent binding of SCH 66336 to FPT by the use of an off-line size exclusion chromatography followed by liquid chromatography-electrospray ionization mass spectrometry (LC-ESI-MS) for the detection of the inhibitor.
Asunto(s)
Transferasas Alquil y Aril/antagonistas & inhibidores , Inhibidores Enzimáticos/farmacología , Piperidinas/farmacología , Piridinas/farmacología , Transferasas Alquil y Aril/metabolismo , Cromatografía en Gel , Inhibidores Enzimáticos/metabolismo , Espectrometría de Masas , Peso Molecular , Piperidinas/metabolismo , Desnaturalización Proteica , Piridinas/metabolismo , Espectrometría de Masa por Ionización de ElectrosprayRESUMEN
CDK2 inhibitors containing the related bicyclic heterocycles pyrazolopyrimidines and imidazopyrazines were discovered through high-throughput screening. Crystal structures of inhibitors with these bicyclic cores and two more related ones show that all but one have a common binding mode featuring two hydrogen bonds (H-bonds) to the backbone of the kinase hinge region. Even though ab initio computations indicated that the imidazopyrazine core would bind more tightly to the hinge, pyrazolopyrimidines gain an advantage in potency through participation of N4 in an H-bond network involving two catalytic residues and bridging water molecules. Further insight into inhibitor/CDK2 interactions was gained from analysis of additional crystal structures. Significant gains in potency were obtained by optimizing the fit of hydrophobic substituents to the gatekeeper region of the ATP binding site. The most potent inhibitors have good selectivity.
Asunto(s)
Quinasas Ciclina-Dependientes/antagonistas & inhibidores , Quinasas Ciclina-Dependientes/química , Diseño de Fármacos , Inhibidores Enzimáticos/química , Inhibidores Enzimáticos/farmacología , Sitios de Unión/efectos de los fármacos , Cristalografía por Rayos X , Evaluación Preclínica de Medicamentos , Concentración 50 Inhibidora , Modelos Moleculares , Estructura Molecular , Estructura Terciaria de Proteína , Relación Estructura-ActividadRESUMEN
A series of four bicyclic cores were prepared and evaluated as cyclin-dependent kinase-2 (CDK2) inhibitors. From the in-vitro and cell-based analysis, the pyrazolo[1,5-a]pyrimidine core (represented by 9) emerged as the superior core for further elaboration in the identification of novel CDK2 inhibitors.
Asunto(s)
Quinasa 2 Dependiente de la Ciclina/efectos de los fármacos , Proteínas Inhibidoras de las Quinasas Dependientes de la Ciclina/química , Proteínas Inhibidoras de las Quinasas Dependientes de la Ciclina/farmacología , Inhibidores de Proteínas Quinasas/química , Inhibidores de Proteínas Quinasas/farmacología , Pirazoles/química , Pirazoles/farmacología , Pirimidinas/química , Pirimidinas/farmacología , Sitios de Unión , Cristalografía por Rayos X , Quinasa 2 Dependiente de la Ciclina/química , Proteínas Inhibidoras de las Quinasas Dependientes de la Ciclina/síntesis química , Diseño de Fármacos , Concentración 50 Inhibidora , Estructura Molecular , Unión Proteica , Inhibidores de Proteínas Quinasas/síntesis química , Pirazoles/síntesis química , Pirimidinas/síntesis químicaRESUMEN
Properly substituted pyrazolo[1,5-a]pyrimidines are potent and selective CDK2 inhibitors. Compound 15j is orally available and showed efficacy in a mouse A2780 xenograft model.
Asunto(s)
Quinasa 2 Dependiente de la Ciclina/antagonistas & inhibidores , Pirazoles/química , Pirazoles/farmacología , Piridinas/química , Piridinas/farmacología , Administración Oral , Animales , Cristalografía por Rayos X , Quinasa 2 Dependiente de la Ciclina/efectos de los fármacos , Perros , Ensayos de Selección de Medicamentos Antitumorales , Haplorrinos , Ratones , Modelos Animales , Modelos Moleculares , Estructura Molecular , Pirazoles/síntesis química , Piridinas/síntesis química , Ratas , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
Farnesyltransferase inhibitors identified from an ECLiPS library were optimized using solution-phase synthesis. X-ray crystallography of inhibited complexes was used to identify substructures that coordinate to the active site zinc. The X-ray structures were ultimately used to guide the design of second-generation analogs with FTase IC(50)s of less than 1.0 nM.
Asunto(s)
Inhibidores Enzimáticos/farmacología , Farnesiltransferasa/antagonistas & inhibidores , Biblioteca de Péptidos , Zinc/química , Animales , Sitios de Unión , Catálisis , Cristalografía por Rayos X , Inhibidores Enzimáticos/síntesis química , Farnesiltransferasa/síntesis química , Concentración 50 Inhibidora , Ratones , Células 3T3 NIH , Relación Estructura-ActividadRESUMEN
The cyclin dependent kinases, Cdks, are potential targets for new anticancer therapy. Dysregulation of the cell cycle is common during tumorigenesis, and inhibition of certain Cdks has been shown to inhibit tumor cell growth, induce apoptosis and cause tumor regressions in animal models. This review discusses the rationale for inhibiting Cdks as an approach to cancer therapy and the status of Cdk inhibitors in clinical trials. Compounds resulting from a patent literature search from 2003 to July, 2005 are discussed.
Asunto(s)
Antineoplásicos/farmacología , Quinasas Ciclina-Dependientes/antagonistas & inhibidores , Animales , Apoptosis/efectos de los fármacos , Ciclo Celular/efectos de los fármacos , Ensayos Clínicos como Asunto , Quinasas Ciclina-Dependientes/fisiología , Humanos , Neoplasias/tratamiento farmacológico , Neoplasias/enzimología , Patentes como AsuntoRESUMEN
Farnesyltransferase (FT) inhibitors were originally designed as anticancer agents, and were thought to act by inhibiting the farnesylation of mutant Ras proteins. However, these compounds were subsequently demonstrated to have antitumor effects even in the absence of Ras mutations and it has now become clear that other protein targets are involved. This article discusses the preclinical and clinical development of FT inhibitors. To date, tipifarnib (Zarnestra; Janssen Pharmaceutica NV) and lonafarnib (Sarasar; Schering-Plough Research Institute) are the only two FT inhibitors to have been evaluated in phase III clinical trials. The clinical results of these two compounds are presented below, with emphasis on ways of enhancing the possibility of a successful FT inhibitor anticancer drug. Details of new FT inhibitors disclosed since the beginning of 2003 are also included.
Asunto(s)
Transferasas Alquil y Aril/antagonistas & inhibidores , Transferasas Alquil y Aril/uso terapéutico , Antineoplásicos/uso terapéutico , Transferasas Alquil y Aril/farmacología , Animales , Antineoplásicos/farmacología , Ensayos Clínicos Fase II como Asunto , Ensayos Clínicos Fase III como Asunto , Sistemas de Liberación de Medicamentos , Ensayos de Selección de Medicamentos Antitumorales , Farnesiltransferasa , Humanos , Estructura Molecular , Proteínas Oncogénicas/biosíntesis , Proteínas Oncogénicas/efectos de los fármacosRESUMEN
MAPK (mitogen-activated protein kinase) pathways constitute major regulators of cellular transcriptional programmes. We analysed the ERK1,2 (extracellular-signal-regulated kinase 1,2) transcriptome in a non-transformed MEC (mammary epithelial cell) line, MCF-12A, utilizing rAd MEK1EE, a recombinant adenovirus encoding constitutively active MEK1 (MAPK/ERK kinase 1). rAd MEK1EE infection induced morphological changes and DNA synthesis which were inhibited by the MEK1,2 inhibitor PD184352. Hierarchical clustering of data derived from seven time points over 24 h identified 430 and 305 co-ordinately up-regulated and down-regulated genes respectively. c-Myc binding sites were identified in the promoters of most of these up-regulated genes. A total of 46 candidate effectors of the Raf/MEK/ERK1,2 pathway in MECs were identified by comparing our dataset with previously reported Raf-1-regulated genes. These analyses led to the identification of a suite of growth factors co-ordinately induced by MEK1EE, including multiple ErbB ligands, vascular endothelial growth factor and PHRP (parathyroid hormone-related protein). PHRP is the primary mediator of humoral hypercalcaemia of malignancy, and has been implicated in metastasis to bone. We demonstrate that PHRP is secreted by MEK1EE-expressing cells. This secretion is inhibited by PD184352, but not by ErbB inhibitors. Our results suggest that, in addition to anti-proliferative properties, MEK1,2 inhibitors may be anti-angiogenic and possess therapeutic utility in the treatment of PHRP-positive tumours.
Asunto(s)
Mama/citología , Mama/enzimología , Células Epiteliales/enzimología , Proteína Quinasa 1 Activada por Mitógenos/genética , Proteína Quinasa 3 Activada por Mitógenos/genética , Transcripción Genética , Adenoviridae/genética , Apoptosis/genética , Sitios de Unión/genética , Ciclo Celular/fisiología , Línea Celular , Mapeo Cromosómico/métodos , Citoesqueleto/enzimología , Citoesqueleto/metabolismo , Reparación del ADN/genética , Fosfatasa 1 de Especificidad Dual , Regulación Enzimológica de la Expresión Génica/genética , Regulación Enzimológica de la Expresión Génica/fisiología , Genes/fisiología , Genes BRCA1/fisiología , Genes BRCA2/fisiología , Genes Inmediatos-Precoces/genética , Vectores Genéticos/biosíntesis , Humanos , MAP Quinasa Quinasa 1/genética , MAP Quinasa Quinasa 1/fisiología , Proteína Quinasa 1 Activada por Mitógenos/fisiología , Proteína Quinasa 3 Activada por Mitógenos/fisiología , Análisis de Secuencia por Matrices de Oligonucleótidos/métodos , Proteína Fosfatasa 1 , Proteínas Tirosina Fosfatasas/genética , Proteínas Tirosina Fosfatasas/fisiología , Proteínas Proto-Oncogénicas c-raf/genética , Factores de Transcripción/genéticaRESUMEN
The 10-bromobenzocycloheptapyridyl farnesyl transferase inhibitor (FTI) Sch-66336 (1) is currently under clinical evaluation for the treatment of human cancers. During structure-activity relationship development leading to 1, 10-bromobenzocycloheptapyridyl FTIs were found to be more potent than analogous compounds lacking the 10-Br substituent. This potency enhancement was believed to be due, in part, to an increase in conformational rigidity as the 10-bromo substituent could restrict the conformation of the appended C(11) piperidyl substituent in an axial orientation. A novel and potent class of FTIs, represented by indolocycloheptapyridine Sch-207758 [(+)-10a], have been designed based on this principle. Although structural and thermodynamic results suggest that entropy plays a crucial role in the increased potency observed with (+)-10a through conformational constraints and solvation effects, the results also indicate that the indolocycloheptapyridine moiety in (+)-10a provides increased hydrophobic interactions with the protein through the addition of the indole group. This report details the X-ray structure and the thermodynamic and pharmacokinetic profiles of (+)-10a, as well as the synthesis of indolocycloheptapyridine FTIs and their potencies in biochemical and biological assays.