RESUMEN
Although therapeutic interventions of signal-transduction cascades with targeted kinase inhibitors are a well-established strategy, drug-discovery efforts to identify targeted phosphatase inhibitors have proven challenging. Herein we report a series of allosteric, small-molecule inhibitors of wild-type p53-induced phosphatase (Wip1), an oncogenic phosphatase common to multiple cancers. Compound binding to Wip1 is dependent on a 'flap' subdomain located near the Wip1 catalytic site that renders Wip1 structurally divergent from other members of the protein phosphatase 2C (PP2C) family and that thereby confers selectivity for Wip1 over other phosphatases. Treatment of tumor cells with the inhibitor GSK2830371 increases phosphorylation of Wip1 substrates and causes growth inhibition in both hematopoietic tumor cell lines and Wip1-amplified breast tumor cells harboring wild-type TP53. Oral administration of Wip1 inhibitors in mice results in expected pharmacodynamic effects and causes inhibition of lymphoma xenograft growth. To our knowledge, GSK2830371 is the first orally active, allosteric inhibitor of Wip1 phosphatase.
Asunto(s)
Aminopiridinas/química , Dipéptidos/química , Inhibidores Enzimáticos/farmacología , Fosfoproteínas Fosfatasas/antagonistas & inhibidores , Administración Oral , Regulación Alostérica , Secuencias de Aminoácidos , Aminopiridinas/farmacología , Animales , Antineoplásicos/química , Antineoplásicos/farmacología , Dominio Catalítico , Línea Celular Tumoral , Dipéptidos/farmacología , Modelos Animales de Enfermedad , Ensayos de Selección de Medicamentos Antitumorales , Activación Enzimática/efectos de los fármacos , Inhibidores Enzimáticos/química , Femenino , Xenoinjertos , Humanos , Ratones , Ratones SCID , Modelos Biológicos , Neoplasias , Proteína Fosfatasa 2CRESUMEN
A series of 1,2,4-triazolo[1,5-a]pyrimidin-7(3H)-ones with excellent enzyme inhibition, improved isoform selectivity, and excellent inhibition of downstream phosphorylation of AKT has been identified. Several compounds in the series demonstrated potent (â¼ 0.100 µM IC(50)) growth inhibition in a PTEN deficient cancer cell line.
Asunto(s)
Inhibidores de las Quinasa Fosfoinosítidos-3 , Inhibidores de Proteínas Quinasas/química , Antineoplásicos/síntesis química , Antineoplásicos/química , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Humanos , Fosfohidrolasa PTEN/deficiencia , Isoformas de Proteínas/antagonistas & inhibidores , Pirimidinas , Relación Estructura-Actividad , Especificidad por SustratoRESUMEN
A series of PI3K-beta selective inhibitors, imidazo[1,2-a]-pyrimidin-5(1H)-ones, has been rationally designed based on the docking model of the more potent R enantiomer of TGX-221, identified by a chiral separation, in a PI3K-beta homology model. Synthesis and SAR of this novel chemotype are described. Several compounds in the series demonstrated potent growth inhibition in a PTEN-deficient breast cancer cell line MDA-MB-468 under anchorage independent conditions.
Asunto(s)
Antineoplásicos/síntesis química , Imidazoles/síntesis química , Inhibidores de las Quinasa Fosfoinosítidos-3 , Inhibidores de Proteínas Quinasas/síntesis química , Pirimidinonas/síntesis química , Antineoplásicos/farmacología , Sitios de Unión , Neoplasias de la Mama , Línea Celular Tumoral , Ensayos de Selección de Medicamentos Antitumorales , Femenino , Eliminación de Gen , Humanos , Imidazoles/farmacología , Isoenzimas/antagonistas & inhibidores , Isoenzimas/metabolismo , Cinética , Modelos Moleculares , Fosfohidrolasa PTEN/deficiencia , Fosfohidrolasa PTEN/genética , Fosfatidilinositol 3-Quinasa/metabolismo , Unión Proteica , Inhibidores de Proteínas Quinasas/farmacología , Pirimidinonas/farmacología , Relación Estructura-ActividadRESUMEN
8-Oxoguanine DNA glycosylase (OGG1) initiates base excision repair of the oxidative DNA damage product 8-oxoguanine. OGG1 is bifunctional; catalyzing glycosyl bond cleavage, followed by phosphodiester backbone incision via a ß-elimination apurinic lyase reaction. The product from the glycosylase reaction, 8-oxoguanine, and its analogues, 8-bromoguanine and 8-aminoguanine, trigger the rate-limiting AP lyase reaction. The precise activation mechanism remains unclear. The product-assisted catalysis hypothesis suggests that 8-oxoguanine and analogues bind at the product recognition (PR) pocket to enhance strand cleavage as catalytic bases. Alternatively, they may allosterically activate OGG1 by binding outside of the PR pocket to induce an active-site conformational change to accelerate apurinic lyase. Herein, steady-state kinetic analyses demonstrated random binding of substrate and activator. 9-Deazaguanine, which can't function as a substrate-competent base, activated OGG1, albeit with a lower Emax value than 8-bromoguanine and 8-aminoguanine. Random compound screening identified small molecules with Emax values similar to 8-bromoguanine. Paraquat-induced mitochondrial dysfunction was attenuated by several small molecule OGG1 activators; benefits included enhanced mitochondrial membrane and DNA integrity, less cytochrome c translocation, ATP preservation, and mitochondrial membrane dynamics. Our results support an allosteric mechanism of OGG1 and not product-assisted catalysis. OGG1 small molecule activators may improve mitochondrial function in oxidative stress-related diseases.
Asunto(s)
ADN Glicosilasas , Regulación Alostérica , ADN Glicosilasas/metabolismo , Reparación del ADN , Guanina/análogos & derivados , Mitocondrias/metabolismo , Especificidad por SustratoRESUMEN
The synthesis and evaluation of tetrasubstituted aminopyridines, bearing novel azaindazole hinge binders, as potent AKT inhibitors are described. Compound 14c was identified as a potent AKT inhibitor that demonstrated reduced CYP450 inhibition and an improved developability profile compared to those of previously described trisubstituted pyridines. It also displayed dose-dependent inhibition of both phosphorylation of GSK3beta and tumor growth in a BT474 tumor xenograft model in mice.
Asunto(s)
Aminopiridinas/química , Sistema Enzimático del Citocromo P-450/metabolismo , Canales de Potasio Éter-A-Go-Go/metabolismo , Inhibidores de Proteínas Quinasas/química , Proteínas Proto-Oncogénicas c-akt/antagonistas & inhibidores , Pirazinas/química , Piridinas/química , Aminopiridinas/síntesis química , Aminopiridinas/farmacocinética , Animales , Línea Celular Tumoral , Perros , Canal de Potasio ERG1 , Glucógeno Sintasa Quinasa 3/antagonistas & inhibidores , Glucógeno Sintasa Quinasa 3/metabolismo , Glucógeno Sintasa Quinasa 3 beta , Haplorrinos , Humanos , Ratones , Fosforilación , Inhibidores de Proteínas Quinasas/síntesis química , Inhibidores de Proteínas Quinasas/farmacocinética , Proteínas Proto-Oncogénicas c-akt/metabolismo , Pirazinas/síntesis química , Pirazinas/farmacocinética , Ratas , Relación Estructura-Actividad , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
AKT inhibitors containing an imidazopyridine aminofurazan scaffold have been optimized. We have previously disclosed identification of the AKT inhibitor GSK690693, which has been evaluated in clinical trials in cancer patients. Herein we describe recent efforts focusing on investigating a distinct region of this scaffold that have afforded compounds (30 and 32) with comparable activity profiles to that of GSK690693.
Asunto(s)
Oxadiazoles/síntesis química , Inhibidores de Proteínas Quinasas/síntesis química , Proteínas Proto-Oncogénicas c-akt/antagonistas & inhibidores , Animales , Línea Celular , Línea Celular Tumoral , Cristalografía por Rayos X , Humanos , Oxadiazoles/química , Oxadiazoles/farmacología , Oxadiazoles/uso terapéutico , Inhibidores de Proteínas Quinasas/farmacología , Estructura Secundaria de Proteína/fisiología , Proteínas Proto-Oncogénicas c-akt/metabolismo , Relación Estructura-ActividadRESUMEN
Significant resource is spent by drug discovery project teams to generate numerous, yet unique target constructs for the multiple platforms used to drive drug discovery programs including: functional assays, biophysical studies, structural biology, and biochemical high throughput screening campaigns. To improve this process, we developed Modular Protein Ligation (MPL), a combinatorial reagent platform utilizing Expressed Protein Ligation to site-specifically label proteins at the C-terminus with a variety of cysteine-lysine dipeptide conjugates. Historically, such proteins have been chemically labeled non-specifically through surface amino acids. To demonstrate the feasibility of this approach, we first applied MPL to proteins of varying size in different target classes using different recombinant protein expression systems, which were then evaluated in several different downstream assays. A key advantage to the implementation of this paradigm is that one construct can generate multiple final products, significantly streamlining the reagent generation for multiple early drug discovery project teams.
Asunto(s)
Descubrimiento de Drogas/métodos , Proteínas/metabolismo , Animales , Estudios de Factibilidad , Humanos , Ligandos , Ratones , Modelos Moleculares , Conformación Proteica , Proteínas/químicaRESUMEN
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
Oncogenic BRAF alleles are both necessary and sufficient for cellular transformation, suggesting that chemical inhibition of the activated mutant protein kinase may reverse the tumor phenotype. Here, we report the characterization of SB-590885, a novel triarylimidazole that selectively inhibits Raf kinases with more potency towards B-Raf than c-Raf. Crystallographic analysis revealed that SB-590885 stabilizes the oncogenic B-Raf kinase domain in an active configuration, which is distinct from the previously reported mechanism of action of the multi-kinase inhibitor, BAY43-9006. Malignant cells expressing oncogenic B-Raf show selective inhibition of mitogen-activated protein kinase activation, proliferation, transformation, and tumorigenicity when exposed to SB-590885, whereas other cancer cell lines and normal cells display variable sensitivities or resistance to similar treatment. These studies support the validation of oncogenic B-Raf as a target for cancer therapy and provide the first evidence of a correlation between the expression of oncogenic BRAF alleles and a positive response to a selective B-Raf inhibitor.
Asunto(s)
Imidazoles/uso terapéutico , Neoplasias/tratamiento farmacológico , Proteínas Proto-Oncogénicas B-raf/antagonistas & inhibidores , Alelos , Animales , Western Blotting , Línea Celular Tumoral , Movimiento Celular/efectos de los fármacos , Proliferación Celular/efectos de los fármacos , Cristalización , Cristalografía por Rayos X , Quinasas MAP Reguladas por Señal Extracelular/metabolismo , Femenino , Células HT29 , Humanos , Imidazoles/química , Ratones , Ratones Desnudos , Modelos Moleculares , Estructura Molecular , Mutación/genética , Neoplasias/enzimología , Neoplasias/patología , Fosforilación/efectos de los fármacos , Conformación Proteica/efectos de los fármacos , Inhibidores de Proteínas Quinasas/química , Inhibidores de Proteínas Quinasas/uso terapéutico , Proteínas Proto-Oncogénicas B-raf/química , Proteínas Proto-Oncogénicas B-raf/genética , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
CAK1 encodes a protein kinase in Saccharomyces cerevisiae whose sole essential mitotic role is to activate the Cdc28p cyclin-dependent kinase by phosphorylation of threonine-169 in its activation loop. SMK1 encodes a sporulation-specific mitogen-activated protein (MAP) kinase homolog that is required to regulate the postmeiotic events of spore wall assembly. CAK1 was previously identified as a multicopy suppressor of a weakened smk1 mutant and shown to be required for spore wall assembly. Here we show that Smk1p, like other MAP kinases, is phosphorylated in its activation loop and that Smk1p is not activated in a cak1 missense mutant. Strains harboring a hyperactivated allele of CDC28 that is CAK1 independent and that lacks threonine-169 still require CAK1 to activate Smk1p. The data indicate that Cak1p functions upstream of Smk1p by activating a protein kinase other than Cdc28p. We also found that mutants lacking CAK1 are blocked early in meiotic development, as they show substantial delays in premeiotic DNA synthesis and defects in the expression of sporulation-specific genes, including IME1. The early meiotic role of Cak1p, like the postmeiotic role in the Smk1p pathway, is CDC28 independent. The data indicate that Cak1p activates multiple steps in meiotic development through multiple protein kinase targets.
Asunto(s)
Proteína Quinasa CDC28 de Saccharomyces cerevisiae/metabolismo , Quinasas Ciclina-Dependientes , Proteínas Quinasas Activadas por Mitógenos/metabolismo , Proteínas Serina-Treonina Quinasas/metabolismo , Proteínas de Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/fisiología , Esporas Fúngicas/fisiología , Proteína Quinasa CDC28 de Saccharomyces cerevisiae/química , ADN de Hongos/biosíntesis , Activación Enzimática , Epítopos/química , Epítopos/metabolismo , Genes Fúngicos , Meiosis/fisiología , Proteínas Quinasas Activadas por Mitógenos/genética , Mutagénesis Sitio-Dirigida , Fosforilación , Estructura Secundaria de Proteína , Proteínas Recombinantes de Fusión/metabolismo , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/ultraestructura , Proteínas de Saccharomyces cerevisiae/química , Proteínas de Saccharomyces cerevisiae/genética , Quinasa Activadora de Quinasas Ciclina-DependientesRESUMEN
We report here the first inhibitor-bound structure of a mitotic motor protein. The 1.9 A resolution structure of the motor domain of KSP, bound with the small molecule monastrol and Mg2+ x ADP, reveals that monastrol confers inhibition by "induced-fitting" onto the protein some 12 A away from the catalytic center of the enzyme, resulting in the creation of a previously non-existing binding pocket. The structure provides new insights into the biochemical and mechanical mechanisms of the mitotic motor domain. Inhibition of KSP provides a novel mechanism to arrest mitotic spindle formation, a target of several approved and investigative anti-cancer agents. The structural information gleaned from this novel pocket offers a new angle for the design of anti-mitotic agents.
Asunto(s)
Cinesinas/antagonistas & inhibidores , Cinesinas/química , Pirimidinas/farmacología , Tionas/farmacología , Adenosina Difosfato/química , Adenosina Difosfato/metabolismo , Sitios de Unión , Cristalización , Cristalografía por Rayos X , Humanos , Magnesio/metabolismo , Microtúbulos/química , Mitosis , Modelos Moleculares , Proteínas Motoras Moleculares , Unión Proteica/genética , Conformación Proteica , Estructura Terciaria de Proteína , Relación Estructura-ActividadRESUMEN
In the search of PI3K p110α wild type and H1047R mutant selective small molecule leads, an encoded library technology (ELT) campaign against the desired target proteins was performed which led to the discovery of a selective chemotype for PI3K isoforms from a three-cycle DNA encoded library. An X-ray crystal structure of a representative inhibitor from this chemotype demonstrated a unique binding mode in the p110α protein.
RESUMEN
Tumor cells upregulate many cell signaling pathways, with AKT being one of the key kinases to be activated in a variety of malignancies. GSK2110183 and GSK2141795 are orally bioavailable, potent inhibitors of the AKT kinases that have progressed to human clinical studies. Both compounds are selective, ATP-competitive inhibitors of AKT 1, 2 and 3. Cells treated with either compound show decreased phosphorylation of several substrates downstream of AKT. Both compounds have desirable pharmaceutical properties and daily oral dosing results in a sustained inhibition of AKT activity as well as inhibition of tumor growth in several mouse tumor models of various histologic origins. Improved kinase selectivity was associated with reduced effects on glucose homeostasis as compared to previously reported ATP-competitive AKT kinase inhibitors. In a diverse cell line proliferation screen, AKT inhibitors showed increased potency in cell lines with an activated AKT pathway (via PI3K/PTEN mutation or loss) while cell lines with activating mutations in the MAPK pathway (KRAS/BRAF) were less sensitive to AKT inhibition. Further investigation in mouse models of KRAS driven pancreatic cancer confirmed that combining the AKT inhibitor, GSK2141795 with a MEK inhibitor (GSK2110212; trametinib) resulted in an enhanced anti-tumor effect accompanied with greater reduction in phospho-S6 levels. Taken together these results support clinical evaluation of the AKT inhibitors in cancer, especially in combination with MEK inhibitor.
Asunto(s)
Antineoplásicos/farmacología , Diaminas/farmacología , Regulación Neoplásica de la Expresión Génica , Neoplasias Pancreáticas/tratamiento farmacológico , Inhibidores de Proteínas Quinasas/farmacología , Pirazoles/farmacología , Carga Tumoral/efectos de los fármacos , Administración Oral , Animales , Antineoplásicos/síntesis química , Glucemia/metabolismo , Línea Celular Tumoral , Diaminas/síntesis química , Evaluación Preclínica de Medicamentos , Sinergismo Farmacológico , Femenino , Humanos , Quinasas Quinasa Quinasa PAM/antagonistas & inhibidores , Quinasas Quinasa Quinasa PAM/genética , Quinasas Quinasa Quinasa PAM/metabolismo , Ratones , Ratones SCID , Fosfohidrolasa PTEN/antagonistas & inhibidores , Fosfohidrolasa PTEN/genética , Fosfohidrolasa PTEN/metabolismo , Neoplasias Pancreáticas/enzimología , Neoplasias Pancreáticas/genética , Neoplasias Pancreáticas/patología , Fosfatidilinositol 3-Quinasas/genética , Fosfatidilinositol 3-Quinasas/metabolismo , Inhibidores de las Quinasa Fosfoinosítidos-3 , Inhibidores de Proteínas Quinasas/síntesis química , Proteínas Proto-Oncogénicas c-akt/antagonistas & inhibidores , Proteínas Proto-Oncogénicas c-akt/genética , Proteínas Proto-Oncogénicas c-akt/metabolismo , Pirazoles/síntesis química , Proteínas Quinasas S6 Ribosómicas/antagonistas & inhibidores , Proteínas Quinasas S6 Ribosómicas/genética , Proteínas Quinasas S6 Ribosómicas/metabolismo , Transducción de Señal , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
A series of novel [3a,4]dihydropyrazolo[1,5a]pyrimidines were identified, which were highly potent and selective inhibitors of PI3Kß. The template afforded the opportunity to develop novel SAR for both the hinge-binding (R3) and back-pocket (R4) substitutents. While cellular potency was relatively modest due to high protein binding, the series displayed low clearance in rat, mouse, and monkey.
RESUMEN
A novel thiazolopyrimidinone series of PI3K-beta selective inhibitors has been identified. This chemotype has provided an excellent tool compound, 18, that showed potent growth inhibition in the PTEN-deficient breast cancer cell line MDA-MB-468 under anchorage-independent conditions, and it also demonstrated pharmacodynamic effects and efficacy in a PTEN-deficient prostate cancer PC-3 xenograft mouse model.
RESUMEN
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
Overexpression of AKT has an antiapoptotic effect in many cell types, and expression of dominant negative AKT blocks the ability of a variety of growth factors to promote survival. Therefore, inhibitors of AKT kinase activity might be useful as monotherapy for the treatment of tumors with activated AKT. Herein, we describe our lead optimization studies culminating in the discovery of compound 3g (GSK690693). Compound 3g is a novel ATP competitive, pan-AKT kinase inhibitor with IC 50 values of 2, 13, and 9 nM against AKT1, 2, and 3, respectively. An X-ray cocrystal structure was solved with 3g and the kinase domain of AKT2, confirming that 3g bound in the ATP binding pocket. Compound 3g potently inhibits intracellular AKT activity as measured by the inhibition of the phosphorylation levels of GSK3beta. Intraperitoneal administration of 3g in immunocompromised mice results in the inhibition of GSK3beta phosphorylation and tumor growth in human breast carcinoma (BT474) xenografts.
Asunto(s)
Oxadiazoles/farmacología , Inhibidores de Proteínas Quinasas/farmacología , Proteínas Proto-Oncogénicas c-akt/antagonistas & inhibidores , Animales , Femenino , Espectroscopía de Resonancia Magnética , Espectrometría de Masas , Ratones , Ratones SCID , Modelos Moleculares , Oxadiazoles/química , Oxadiazoles/metabolismo , Inhibidores de Proteínas Quinasas/química , Inhibidores de Proteínas Quinasas/metabolismo , Proteínas Proto-Oncogénicas c-akt/metabolismo , Especificidad por SustratoRESUMEN
We have developed a highly sensitive assay of MEK-mediated ATP hydrolysis by coupling the formation of ADP to NADH oxidation through the enzymes pyruvate kinase and lactate dehydrogenase. Robust ATP hydrolysis is catalyzed by phosphorylated MEK in the absence of the protein substrate ERK. This ERK-uncoupled ATPase activity is dependent on the phosphorylation status of MEK and is abrogated by the selective MEK kinase inhibitor U0126. ADP production is concomitant with Raf-mediated phosphorylation of MEK. Based on this finding, a coupled Raf/MEK assay is developed for measuring the Raf activity. A kinetic treatment derived under steady-state assumptions is presented for the analysis of the reaction progress curve generated by this coupled assay. We have shown that inhibitory potency of selective Raf inhibitors can be determined accurately by this assay.
Asunto(s)
Adenosina Trifosfatasas/metabolismo , MAP Quinasa Quinasa 1/metabolismo , Adenosina Trifosfato/química , Animales , Butadienos/farmacología , Escherichia coli/metabolismo , Quinasas MAP Reguladas por Señal Extracelular/metabolismo , Humanos , Hidrólisis , Cinética , Nitrilos/farmacología , Fosfatos/metabolismo , Fosforilación , Proteínas Proto-Oncogénicas B-raf/metabolismo , Conejos , Transducción de Señal , Factores de TiempoRESUMEN
Molecular modeling in combination with X-ray crystallographic information was employed to identify a region of the kinesin spindle protein (KSP) binding site not fully utilized by our first generation inhibitors. We discovered that by appending a propylamine substituent at the C5 carbon of a dihydropyrazole core, we could effectively fill this unoccupied region of space and engage in a hydrogen-bonding interaction with the enzyme backbone. This change led to a second generation compound with increased potency, a 400-fold enhancement in aqueous solubility at pH 4, and improved dog pharmacokinetics relative to the first generation compound.
Asunto(s)
Diseño de Fármacos , Cinesinas/antagonistas & inhibidores , Pirazoles/química , Pirazoles/farmacología , Alquilación , Sitio Alostérico , Aminación , Animales , Cristalografía por Rayos X , Perros , Hidroxilación , Cinesinas/química , Cinesinas/metabolismo , Mitosis , Modelos Moleculares , Estructura Molecular , Pirazoles/síntesis química , Pirazoles/farmacocinética , Solubilidad , Relación Estructura-Actividad , AguaRESUMEN
The evolution of 2,4-diaryl-2,5-dihydropyrroles as inhibitors of KSP is described. Introduction of basic amide and urea moieties to the dihydropyrrole nucleus enhanced potency and aqueous solubility, simultaneously, and provided compounds that caused mitotic arrest of A2780 human ovarian carcinoma cells with EC(50)s<10nM. Ancillary hERG activity was evaluated for this series of inhibitors.