RESUMEN
Activation of the inositol-requiring enzyme-1 alpha (IRE1α) protein caused by endoplasmic reticulum stress results in the homodimerization of the N-terminal endoplasmic reticulum luminal domains, autophosphorylation of the cytoplasmic kinase domains, and conformational changes to the cytoplasmic endoribonuclease (RNase) domains, which render them functional and can lead to the splicing of X-box binding protein 1 (XBP 1) mRNA. Herein, we report the first crystal structures of the cytoplasmic portion of a human phosphorylated IRE1α dimer in complex with (R)-2-(3,4-dichlorobenzyl)-N-(4-methylbenzyl)-2,7-diazaspiro(4.5)decane-7-carboxamide, a novel, IRE1α-selective kinase inhibitor, and staurosporine, a broad spectrum kinase inhibitor. (R)-2-(3,4-dichlorobenzyl)-N-(4-methylbenzyl)-2,7-diazaspiro(4.5)decane-7-carboxamide inhibits both the kinase and RNase activities of IRE1α. The inhibitor interacts with the catalytic residues Lys599 and Glu612 and displaces the kinase activation loop to the DFG-out conformation. Inactivation of IRE1α RNase activity appears to be caused by a conformational change, whereby the αC helix is displaced, resulting in the rearrangement of the kinase domain-dimer interface and a rotation of the RNase domains away from each other. In contrast, staurosporine binds at the ATP-binding site of IRE1α, resulting in a dimer consistent with RNase active yeast Ire1 dimers. Activation of IRE1α RNase activity appears to be promoted by a network of hydrogen bond interactions between highly conserved residues across the RNase dimer interface that place key catalytic residues poised for reaction. These data implicate that the intermolecular interactions between conserved residues in the RNase domain are required for activity, and that the disruption of these interactions can be achieved pharmacologically by small molecule kinase domain inhibitors.
Asunto(s)
Endorribonucleasas/antagonistas & inhibidores , Endorribonucleasas/metabolismo , Inhibidores de Proteínas Quinasas/metabolismo , Proteínas Serina-Treonina Quinasas/antagonistas & inhibidores , Proteínas Serina-Treonina Quinasas/metabolismo , Línea Celular Tumoral , Cristalización , Endorribonucleasas/química , Activación Enzimática/efectos de los fármacos , Activación Enzimática/fisiología , Humanos , Conformación Proteica/efectos de los fármacos , Inhibidores de Proteínas Quinasas/química , Inhibidores de Proteínas Quinasas/farmacología , Proteínas Serina-Treonina Quinasas/química , Estructura Secundaria de Proteína , Estructura Terciaria de ProteínaRESUMEN
The aim of this study was to assess niraparib (MK-4827), a novel poly(ADP-Ribose) polymerase (PARP) inhibitor, for its ability to radiosensitize human tumor cells. Human tumor cells derived from lung, breast and prostate cancers were tested for radiosensitization by niraparib using clonogenic survival assays. Both p53 wild-type and p53-defective lines were included. The ability of niraparib to alter the repair of radiation-induced DNA double strand breaks (DSBs) was determined using detection of γ-H2AX foci and RAD51 foci. Clonogenic survival analyses indicated that micromolar concentrations of niraparib radiosensitized tumor cell lines derived from lung, breast, and prostate cancers independently of their p53 status but not cell lines derived from normal tissues. Niraparib also sensitized tumor cells to H2O2 and converted H2O2-induced single strand breaks (SSBs) into DSBs during DNA replication. These results indicate that human tumor cells are significantly radiosensitized by the potent and selective PARP-1 inhibitor, niraparib, in the in vitro setting. The mechanism of this effect appears to involve a conversion of sublethal SSBs into lethal DSBs during DNA replication due to the inhibition of base excision repair by the drug. Taken together, our findings strongly support the clinical evaluation of niraparib in combination with radiation.
Asunto(s)
Indazoles/farmacología , Piperidinas/farmacología , Inhibidores de Poli(ADP-Ribosa) Polimerasas , Fármacos Sensibilizantes a Radiaciones/farmacología , Neoplasias de la Mama/genética , Neoplasias de la Mama/metabolismo , Neoplasias de la Mama/patología , Carcinoma de Pulmón de Células no Pequeñas/genética , Carcinoma de Pulmón de Células no Pequeñas/metabolismo , Carcinoma de Pulmón de Células no Pequeñas/patología , Línea Celular , Línea Celular Tumoral , Supervivencia Celular/efectos de los fármacos , Supervivencia Celular/efectos de la radiación , Roturas del ADN de Doble Cadena/efectos de los fármacos , Roturas del ADN de Doble Cadena/efectos de la radiación , Roturas del ADN de Cadena Simple/efectos de los fármacos , Roturas del ADN de Cadena Simple/efectos de la radiación , Reparación del ADN/efectos de los fármacos , Reparación del ADN/efectos de la radiación , Femenino , Histonas/metabolismo , Humanos , Peróxido de Hidrógeno/farmacología , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/metabolismo , Neoplasias Pulmonares/patología , Masculino , Microscopía Fluorescente , Oxidantes/farmacología , Poli(ADP-Ribosa) Polimerasas/metabolismo , Neoplasias de la Próstata/genética , Neoplasias de la Próstata/metabolismo , Neoplasias de la Próstata/patología , Recombinasa Rad51/metabolismo , Ensayo de Tumor de Célula Madre , Proteína p53 Supresora de Tumor/genética , Proteína p53 Supresora de Tumor/metabolismoRESUMEN
Pyridyl aminothiazoles comprise a novel class of ATP-competitive Chk1 inhibitors with excellent inhibitory potential. Modification of the core with ethylenediamine amides provides compounds with low picomolar potency and very high residence times. Investigation of binding parameters of such compounds using X-ray crystallography and molecular dynamics simulations revealed multiple hydrogen bonds to the enzyme backbone as well as stabilization of the conserved water molecules network in the hydrophobic binding region.
Asunto(s)
Antineoplásicos/síntesis química , Inhibidores de Proteínas Quinasas/síntesis química , Proteínas Quinasas/química , Piridinas/síntesis química , Tiazoles/síntesis química , Amidas/química , Antineoplásicos/farmacología , Sitios de Unión , Quinasa 1 Reguladora del Ciclo Celular (Checkpoint 1) , Cristalografía por Rayos X , Diseño de Fármacos , Etilenodiaminas/química , Humanos , Enlace de Hidrógeno , Cinética , Simulación de Dinámica Molecular , Estructura Molecular , Unión Proteica , Inhibidores de Proteínas Quinasas/farmacología , Proteínas Quinasas/metabolismo , Piridinas/farmacología , Relación Estructura-Actividad , Tiazoles/farmacología , Agua/químicaRESUMEN
Translation of significant biochemical activity of pyridyl aminothiazole class of Chk1 inhibitors into functional CEA potency required analysis and adjustment of both physical properties and kinase selectivity profile of the series. The steps toward optimization of cellular potency included elimination of CDK7 activity, reduction of molecular weight and polar surface area and increase in lipophilicity of the molecules in the series.
Asunto(s)
Antineoplásicos/síntesis química , Inhibidores de Proteínas Quinasas/síntesis química , Proteínas Quinasas/química , Piridinas/síntesis química , Tiazoles/síntesis química , Antineoplásicos/farmacología , Puntos de Control del Ciclo Celular/efectos de los fármacos , Línea Celular Tumoral , Permeabilidad de la Membrana Celular , Quinasa 1 Reguladora del Ciclo Celular (Checkpoint 1) , Quinasas Ciclina-Dependientes/antagonistas & inhibidores , Quinasas Ciclina-Dependientes/química , Diseño de Fármacos , Halogenación , Humanos , Cinética , Estructura Molecular , Inhibidores de Proteínas Quinasas/farmacología , Proteínas Quinasas/metabolismo , Piridinas/farmacología , Relación Estructura-Actividad , Tiazoles/farmacología , Quinasa Activadora de Quinasas Ciclina-DependientesRESUMEN
Hepatocellular carcinoma (HCC) is a heterogeneous and highly aggressive malignancy, for which there are no effective cures. Identification of a malignant stemlike subtype of HCC may offer patients with a dismal prognosis a potential targeted therapy using c-MET and Wnt pathway inhibitors. MicroRNAs (miRNAs) show promise as diagnostic and prognostic tools for cancer detection and stratification. Using a TRE-c-Met-driven transgenic HCC mouse model, we identified a cluster of 23 miRNAs that is encoded within the Dlk1-Gtl2 imprinted region on chromosome 12qF1 overexpressed in all of the isolated liver tumors. Interestingly, this region is conserved among mammalian species and maps to the human DLK1-DIO3 region on chromosome 14q32.2. We thus examined the expression of the DLK1-DIO3 miRNA cluster in a cohort of 97 hepatitis B virus-associated HCC patients and identified a subgroup (n = 18) of patients showing strong coordinate overexpression of miRNAs in this cluster but not in other cancer types (breast, lung, kidney, stomach, and colon) that were tested. Expression levels of imprinted gene transcripts from neighboring loci in this 14q32.2 region and from a subset of other imprinted sites were concomitantly elevated in human HCC. Interestingly, overexpression of the DLK1-DIO3 miRNA cluster was positively correlated with HCC stem cell markers (CD133, CD90, EpCAM, Nestin) and associated with a high level of serum α-fetoprotein, a conventional biomarker for liver cancer, and poor survival rate in HCC patients. In conclusion, our findings suggest that coordinate up-regulation of the DLK1-DIO3 miRNA cluster at 14q32.2 may define a novel molecular (stem cell-like) subtype of HCC associated with poor prognosis.
Asunto(s)
Carcinoma Hepatocelular/genética , Carcinoma Hepatocelular/mortalidad , Cromosomas Humanos Par 14/genética , Péptidos y Proteínas de Señalización Intercelular/genética , Yoduro Peroxidasa/genética , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/mortalidad , Proteínas de la Membrana/genética , MicroARNs/genética , Biomarcadores de Tumor/metabolismo , Proteínas de Unión al Calcio , Estudios de Cohortes , Humanos , Hígado/metabolismo , MicroARNs/metabolismo , Familia de Multigenes , Pronóstico , Distribución Tisular , Resultado del Tratamiento , Regulación hacia ArribaRESUMEN
PURPOSE: Radiotherapy is commonly used to treat a variety of solid tumors. However, improvements in the therapeutic ratio for several disease sites are sorely needed, leading us to assess molecularly targeted therapeutics as radiosensitizers. The aim of this study was to assess the wee1 kinase inhibitor, MK-1775, for its ability to radiosensitize human tumor cells. EXPERIMENTAL DESIGN: Human tumor cells derived from lung, breast, and prostate cancers were tested for radiosensitization by MK-1775 using clonogenic survival assays. Both p53 wild-type and p53-defective lines were included. The ability of MK-1775 to abrogate the radiation-induced G2 block, thereby allowing cells harboring DNA lesions to prematurely progress into mitosis, was determined using flow cytometry and detection of γ-H2AX foci. The in vivo efficacy of the combination of MK-1775 and radiation was assessed by tumor growth delay experiments using a human lung cancer cell line growing as a xenograft tumor in nude mice. RESULTS: Clonogenic survival analyses indicated that nanomolar concentrations of MK-1775 radiosensitized p53-defective human lung, breast, and prostate cancer cells but not similar lines with wild-type p53. Consistent with its ability to radiosensitize, MK-1775 abrogated the radiation-induced G2 block in p53-defective cells but not in p53 wild-type lines. MK-1775 also significantly enhanced the antitumor efficacy of radiation in vivo as shown in tumor growth delay studies, again for p53-defective tumors. CONCLUSIONS: These results indicate that p53-defective human tumor cells are significantly radiosensitized by the potent and selective wee1 kinase inhibitor, MK-1775, in both the in vitro and in vivo settings. Taken together, our findings strongly support the clinical evaluation of MK-1775 in combination with radiation.
Asunto(s)
Proteínas de Ciclo Celular/antagonistas & inhibidores , Neoplasias , Proteínas Nucleares/antagonistas & inhibidores , Proteínas Tirosina Quinasas/antagonistas & inhibidores , Pirazoles/farmacología , Pirimidinas/farmacología , Fármacos Sensibilizantes a Radiaciones/farmacología , Proteína p53 Supresora de Tumor/deficiencia , Animales , Antineoplásicos/farmacología , Neoplasias de la Mama/tratamiento farmacológico , Neoplasias de la Mama/radioterapia , Línea Celular Tumoral , Terapia Combinada , Femenino , Puntos de Control de la Fase G2 del Ciclo Celular/efectos de los fármacos , Puntos de Control de la Fase G2 del Ciclo Celular/efectos de la radiación , Humanos , Neoplasias Pulmonares/tratamiento farmacológico , Neoplasias Pulmonares/radioterapia , Masculino , Ratones , Ratones Desnudos , Neoplasias/tratamiento farmacológico , Neoplasias/patología , Neoplasias/radioterapia , Neoplasias de la Próstata/tratamiento farmacológico , Neoplasias de la Próstata/radioterapia , Inhibidores de Proteínas Quinasas/farmacología , Inhibidores de Proteínas Quinasas/uso terapéutico , Pirimidinonas , Trasplante Heterólogo , Proteína p53 Supresora de Tumor/genética , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
This study characterized the preclinical anti-myeloma activity of VE465, a low molecular weight pan-Aurora kinase inhibitor. After 96-h drug exposure, several multiple myeloma (MM) cell lines were more sensitive to VE465 compared to non-malignant cells. The anti-MM activity of VE465 was maintained in the presence of interleukin-6 and, interestingly, enhanced by co-culture with stromal cells. However, primary MM cells were less responsive than cell lines. Combinations with dexamethasone (Dex), doxorubicin (Doxo) and bortezomib showed no antagonism. Our study highlights the potential role of the tumour microenvironment in modulating the activity of this drug class.
Asunto(s)
Antineoplásicos/farmacología , Mieloma Múltiple/patología , Piperazinas/farmacología , Proteínas Serina-Treonina Quinasas/antagonistas & inhibidores , Protocolos de Quimioterapia Combinada Antineoplásica/farmacología , Apoptosis/efectos de los fármacos , Aurora Quinasas , Comunicación Celular/efectos de los fármacos , Ciclo Celular/efectos de los fármacos , Técnicas de Cocultivo , Relación Dosis-Respuesta a Droga , Ensayos de Selección de Medicamentos Antitumorales/métodos , Células Madre Hematopoyéticas/citología , Humanos , Células Tumorales CultivadasRESUMEN
A number of inhibitors of kinesin spindle protein (KSP) have been described, which are known from X-ray crystallography studies to bind to an induced fit pocket defined by the L5 loop. We describe the characterization of eight mutant forms of KSP in which six residues that line this pocket have been altered. Mutants were analyzed by measuring rates of enzyme catalysis, in the presence and absence of six KSP inhibitors of four diverse structural classes and of varied ATP-competition status. Our analysis was in agreement with the model of binding established by the structural studies and suggests that binding energy is well distributed across functional groups in these molecules. The majority of the mutants retained significant enzymatic activity while diminishing inhibitor binding, indicating potential for the development of drug resistance. These data provide detailed information on interactions between inhibitor and binding pocket at the functional group level and enable the development of novel KSP inhibitors.
Asunto(s)
Cinesinas/antagonistas & inhibidores , Adenosina Trifosfato/metabolismo , Secuencia de Aminoácidos , Unión Competitiva , Biocatálisis , Cristalografía por Rayos X , Humanos , Cinesinas/química , Cinesinas/genética , Cinesinas/metabolismo , Datos de Secuencia Molecular , Mutagénesis Sitio-Dirigida , Conformación Proteica , Homología de Secuencia de AminoácidoRESUMEN
A high throughput screening campaign was designed to identify allosteric inhibitors of Chk1 kinase by testing compounds at high concentration. Activity was then observed at K(m) for ATP and at near-physiological concentrations of ATP. This strategy led to the discovery of a non-ATP competitive thioquinazolinone series which was optimized for potency and stability. An X-ray crystal structure for the complex of our best inhibitor bound to Chk1 was solved, indicating that it binds to an allosteric site approximately 13A from the ATP binding site. Preliminary data is presented for several of these compounds.
Asunto(s)
Inhibidores de Proteínas Quinasas/síntesis química , Inhibidores de Proteínas Quinasas/farmacología , Proteínas Quinasas/efectos de los fármacos , Quinazolinas/síntesis química , Quinazolinas/farmacología , Sitios de Unión , Quinasa 1 Reguladora del Ciclo Celular (Checkpoint 1) , Técnicas Químicas Combinatorias , Cristalografía por Rayos X , Humanos , Conformación Molecular , Estructura Molecular , Inhibidores de Proteínas Quinasas/química , Proteínas Quinasas/química , Proteínas Quinasas/metabolismo , Quinazolinas/químicaRESUMEN
PURPOSE: We determined the effects of vorinostat (suberoylanalide hydroxamic acid) and/or MK-0457 (VX-680), an Aurora kinase inhibitor on the cultured human (HL-60, OCI-AML3, and K562) and primary acute myelogenous leukemia (AML) and chronic myelogenous leukemia (CML), as well as on the murine pro-B BaF3 cells with ectopic expression of the unmutated and mutant forms of Bcr-Abl. EXPERIMENTAL DESIGN: Following exposure to MK-0457 and/or vorinostat, apoptosis, loss of viability, as well as activity and levels of Aurora kinase and Bcr-Abl proteins were determined. RESULTS: Treatment with MK-0457 decreased the phosphorylation of Aurora kinase substrates including serine (S)10 on histone H3 and survivin, and led to aberrant mitosis, DNA endoreduplication as well as apoptosis of the cultured human acute leukemia HL-60, OCI-AML3, and K562 cells. Combined treatment with vorinostat and MK-0457 resulted in greater attenuation of Aurora and Bcr-Abl (in K562) kinase activity and levels as well as synergistically induced apoptosis of OCI-AML3, HL-60, and K562 cells. MK-0457 plus vorinostat also induced synergistic apoptosis of BaF3 cells with ectopic overexpression of wild-type or mutant Bcr-Abl. Finally, cotreatment with MK-0457 and vorinostat induced more loss of viability of primary AML and imatinib-refractory CML than treatment with either agent alone, but exhibited minimal toxicity to normal CD34+ progenitor cells. CONCLUSIONS: Combined in vitro treatment with MK-0457 and vorinostat is highly active against cultured and primary leukemia cells. These findings merit in vivo testing of the combination against human AML and CML cells, especially against imatinib mesylate-resistant Bcr-AblT315I-expressing CML Cells.
Asunto(s)
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Ácidos Hidroxámicos/administración & dosificación , Leucemia Mielógena Crónica BCR-ABL Positiva/tratamiento farmacológico , Leucemia Mieloide Aguda/tratamiento farmacológico , Piperazinas/administración & dosificación , Animales , Línea Celular Tumoral , Sinergismo Farmacológico , Proteínas de Fusión bcr-abl/metabolismo , Células HL-60 , Histonas/metabolismo , Humanos , Proteínas Inhibidoras de la Apoptosis , Células K562 , Ratones , Proteínas Asociadas a Microtúbulos/metabolismo , Mutación , Proteínas de Neoplasias/metabolismo , Survivin , VorinostatRESUMEN
Inhibition of kinesin spindle protein (KSP) is a novel mechanism for treatment of cancer with the potential to overcome limitations associated with currently employed cytotoxic agents. Herein, we describe a C2-hydroxymethyl dihydropyrrole KSP inhibitor ( 11) that circumvents hERG channel binding and poor in vivo potency, issues that limited earlier compounds from our program. However, introduction of the C2-hydroxymethyl group caused 11 to be a substrate for cellular efflux by P-glycoprotein (Pgp). Utilizing knowledge garnered from previous KSP inhibitors, we found that beta-fluorination modulated the p K a of the piperidine nitrogen and reduced Pgp efflux, but the resulting compound ( 14) generated a toxic metabolite in vivo. Incorporation of fluorine in a strategic, metabolically benign position by synthesis of an N-methyl-3-fluoro-4-(aminomethyl)piperidine urea led to compound 30 that has an optimal in vitro and metabolic profile. Compound 30 (MK-0731) was recently studied in a phase I clinical trial in patients with taxane-refractory solid tumors.
Asunto(s)
Antineoplásicos/farmacología , Inhibidores Enzimáticos/farmacología , Cinesinas/antagonistas & inhibidores , Neoplasias/enzimología , Piperidinas/farmacología , Pirroles/farmacología , Taxoides/farmacología , Miembro 1 de la Subfamilia B de Casetes de Unión a ATP/metabolismo , Antineoplásicos/uso terapéutico , Inhibidores Enzimáticos/uso terapéutico , Humanos , Neoplasias/tratamiento farmacológico , Taxoides/uso terapéuticoRESUMEN
The kinesin spindle protein (KSP, also known as Eg5) is essential for the proper separation of spindle poles during mitosis, and inhibition results in mitotic arrest and the formation of characteristic monoaster spindles. Several distinct classes of KSP inhibitors have been described previously in the public and patent literature. However, most appear to share a common induced-fit allosteric binding site, suggesting a common mechanism of inhibition. In a high-throughput screen for inhibitors of KSP, a novel class of thiazole-containing inhibitors was identified. Unlike the previously described allosteric KSP inhibitors, the thiazoles described here show ATP competitive kinetic behavior, consistent with binding within the nucleotide binding pocket. Although they bind to a pocket that is highly conserved across kinesins, these molecules exhibit significant selectivity for KSP over other kinesins and other ATP-utilizing enzymes. Several of these compounds are active in cells and produce a phenotype similar to that observed with previously published allosteric inhibitors of KSP.
Asunto(s)
Adenosina Trifosfato/metabolismo , Bioquímica/métodos , Cinesinas/antagonistas & inhibidores , Cinesinas/química , Mitosis , Adenosina Trifosfato/química , Sitio Alostérico , Unión Competitiva , Diseño de Fármacos , Humanos , Cinesinas/metabolismo , Modelos Biológicos , Modelos Químicos , Nucleótidos/química , Fenotipo , Unión Proteica , Tiazoles/farmacologíaRESUMEN
Inspired by previous efforts in the pyrazolobenzoxazine class of KSP inhibitors, the design and synthesis of 1,4-diaryl-4,5-dihydropyrazole inhibitors of KSP are described. Crystallographic evidence of binding mode and in vivo potency data is also highlighted.
Asunto(s)
Diseño de Fármacos , Hidrógeno/química , Cinesinas/antagonistas & inhibidores , Cinesinas/metabolismo , Mitosis/efectos de los fármacos , Pirazoles/química , Pirazoles/farmacología , Sitios de Unión , Cristalografía por Rayos X , Humanos , Modelos Moleculares , Estructura Molecular , Pirazoles/síntesis química , Relación Estructura-ActividadRESUMEN
From HTS lead 1, a novel benzoisoquinolinone class of ATP-competitive Chk1 inhibitors was devised and synthesized via a photochemical route. Using X-ray crystallography as a guide, potency was rapidly enhanced through the installation of a tethered basic amine designed to interact with an acidic residue (Glu91) in the enzyme pocket. Further SAR was explored at the solvent front and near to the H1 pocket and resulted in the discovery of low MW, sub-nanomolar inhibitors of Chk1.
Asunto(s)
Inhibidores Enzimáticos/síntesis química , Inhibidores Enzimáticos/farmacología , Proteínas Quinasas/efectos de los fármacos , Quinolonas/síntesis química , Quinolonas/farmacología , Apoptosis/efectos de los fármacos , Sitios de Unión , Línea Celular Tumoral , Quinasa 1 Reguladora del Ciclo Celular (Checkpoint 1) , Cristalografía por Rayos X , Evaluación Preclínica de Medicamentos , Inhibidores Enzimáticos/química , Humanos , Concentración 50 Inhibidora , Modelos Moleculares , Estructura Molecular , Fotoquímica , Proteínas Quinasas/química , Quinolonas/química , Relación Estructura-ActividadRESUMEN
3,5-diaryl-4,5-dihydropyrazoles were discovered to be potent KSP inhibitors with excellent in vivo potency. These enzyme inhibitors possess desirable physical properties that can be readily modified by incorporation of a weakly basic amine. Careful adjustment of amine basicity was essential for preserving cellular potency in a multidrug resistant cell line while maintaining good aqueous solubility.
Asunto(s)
Amidas/síntesis química , Amidas/farmacología , Antimitóticos/síntesis química , Antimitóticos/farmacología , Cinesinas/antagonistas & inhibidores , Mitosis/efectos de los fármacos , Pirazoles/síntesis química , Pirazoles/farmacología , Miembro 1 de la Subfamilia B de Casetes de Unión a ATP/antagonistas & inhibidores , Antineoplásicos/síntesis química , Antineoplásicos/farmacología , Línea Celular Tumoral , Fenómenos Químicos , Química Física , Diseño de Fármacos , Resistencia a Antineoplásicos , Genes MDR/efectos de los fármacos , Humanos , Indicadores y Reactivos , Solubilidad , Estereoisomerismo , Relación Estructura-ActividadRESUMEN
The development of 2,5-dihydro-4H-pyrazolo[4,3-c]quinolin-4-ones as inhibitors of Chk1 kinase is described. Introduction of a fused ring at the C7/C8 positions of the pyrazoloquinolinone provided an increase in potency while guidance from overlapping inhibitor bound Chk1 X-ray crystal structures contributed to the discovery of a potent and solubilizing propyl amine moiety in compound 52 (Chk1 IC(50)=3.1 nM).
Asunto(s)
Inhibidores de Proteínas Quinasas/farmacología , Proteínas Quinasas/efectos de los fármacos , Quinolonas/farmacología , Quinasa 1 Reguladora del Ciclo Celular (Checkpoint 1) , Cristalografía por Rayos X , Modelos Moleculares , Inhibidores de Proteínas Quinasas/química , Quinolonas/química , Relación Estructura-ActividadRESUMEN
Observations from two structurally related series of KSP inhibitors led to the proposal and discovery of dihydropyrazolobenzoxazines that possess ideal properties for cancer drug development. The synthesis and characterization of this class of inhibitors along with relevant pharmacokinetic and in vivo data are presented. The synthesis is highlighted by a key [3+2] cycloaddition to form the pyrazolobenzoxazine core followed by diastereospecific installation of a quaternary center.
Asunto(s)
Benzoxazinas/química , Benzoxazinas/farmacología , Diseño de Fármacos , Cinesinas/antagonistas & inhibidores , Cinesinas/metabolismo , Mitosis/efectos de los fármacos , Pirazoles/química , Animales , Benzoxazinas/síntesis química , Benzoxazinas/farmacocinética , Línea Celular , Perros , Humanos , Hidrógeno/química , Estructura Molecular , Relación Estructura-ActividadRESUMEN
Installation of a C2-aminopropyl side chain to the 2,4-diaryl-2,5-dihydropyrrole series of kinesin spindle protein (KSP) inhibitors results in potent, water soluble compounds, but the aminopropyl group induces susceptibility to cellular efflux by P-glycoprotein (Pgp). We show that by carefully modulating the basicity of the amino group by beta-fluorination, this series of inhibitors maintains potency against KSP and has greatly improved efficacy in a Pgp-overexpressing cell line. The discovery that cellular efflux by Pgp can be overcome by carefully modulating the basicity of an amine may be of general use to medicinal chemists attempting to transform leading compounds into cancer cell- or CNS-penetrant drugs.
Asunto(s)
Miembro 1 de la Subfamilia B de Casetes de Unión a ATP/fisiología , Flúor/metabolismo , Cinesinas/antagonistas & inhibidores , Propilaminas/farmacología , Pirroles/farmacología , Transporte Biológico , Citoesqueleto , Concentración de Iones de Hidrógeno , Cinesinas/metabolismo , Solubilidad , AguaRESUMEN
Through a comparison of X-ray co-crystallographic data for 1 and 2 in the Chek1 active site, it was hypothesized that the affinity of the indolylquinolinone series (2) for Chek1 kinase would be improved via C6 substitution into the hydrophobic region I (HI) pocket. An efficient route to 6-bromo-3-indolyl-quinolinone (9) was developed, and this series was rapidly optimized for potency by modification at C6. A general trend was observed among these low nanomolar Chek1 inhibitors that compounds with multiple basic amines, or elevated polar surface area (PSA) exhibited poor cell potency. Minimization of these parameters (basic amines, PSA) resulted in Chek1 inhibitors with improved cell potency, and preliminary pharmacokinetic data are presented for several of these compounds.
Asunto(s)
Inhibidores Enzimáticos/farmacología , Indoles/química , Proteínas Quinasas/efectos de los fármacos , Quinolonas/química , Animales , Sitios de Unión , Quinasa 1 Reguladora del Ciclo Celular (Checkpoint 1) , Cristalografía por Rayos X , Diseño de Fármacos , Inhibidores Enzimáticos/química , Inhibidores Enzimáticos/farmacocinética , Humanos , Interacciones Hidrofóbicas e Hidrofílicas , Proteínas Quinasas/metabolismo , Relación Estructura-ActividadRESUMEN
The development of 3-(indol-2-yl)indazoles as inhibitors of Chek1 kinase is described. Introduction of amides and heteroaryl groups at the C6 position of the indazole ring system provided sufficient Chek1 potency and selectivity over Cdk7 to permit escape from DNA damage-induced arrest in a cellular assay. Enzyme potency against Chek1 was optimized by the incorporation of a hydroxymethyl triazole moiety in compound 21 (Chek1 IC(50)=0.30nM) that was shown by X-ray crystallography to displace one of three highly conserved water molecules in the HI region of the ATP-binding cleft.