Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 6 de 6
Filtrar
1.
Nature ; 523(7559): 183-188, 2015 Jul 09.
Artículo en Inglés | MEDLINE | ID: mdl-26131937

RESUMEN

Lenalidomide is a highly effective treatment for myelodysplastic syndrome (MDS) with deletion of chromosome 5q (del(5q)). Here, we demonstrate that lenalidomide induces the ubiquitination of casein kinase 1A1 (CK1α) by the E3 ubiquitin ligase CUL4-RBX1-DDB1-CRBN (known as CRL4(CRBN)), resulting in CK1α degradation. CK1α is encoded by a gene within the common deleted region for del(5q) MDS and haploinsufficient expression sensitizes cells to lenalidomide therapy, providing a mechanistic basis for the therapeutic window of lenalidomide in del(5q) MDS. We found that mouse cells are resistant to lenalidomide but that changing a single amino acid in mouse Crbn to the corresponding human residue enables lenalidomide-dependent degradation of CK1α. We further demonstrate that minor side chain modifications in thalidomide and a novel analogue, CC-122, can modulate the spectrum of substrates targeted by CRL4(CRBN). These findings have implications for the clinical activity of lenalidomide and related compounds, and demonstrate the therapeutic potential of novel modulators of E3 ubiquitin ligases.


Asunto(s)
Quinasa de la Caseína I/metabolismo , Síndromes Mielodisplásicos/genética , Síndromes Mielodisplásicos/fisiopatología , Talidomida/análogos & derivados , Ubiquitinación/efectos de los fármacos , Secuencia de Aminoácidos , Animales , Quinasa de la Caseína I/genética , Línea Celular , Regulación de la Expresión Génica/efectos de los fármacos , Células HEK293 , Humanos , Factores Inmunológicos/farmacología , Células Jurkat , Células K562 , Lenalidomida , Ratones , Datos de Secuencia Molecular , Péptido Hidrolasas/química , Proteolisis/efectos de los fármacos , Alineación de Secuencia , Eliminación de Secuencia , Especificidad de la Especie , Talidomida/farmacología , Ubiquitina-Proteína Ligasas/metabolismo
2.
Clin Cancer Res ; 12(16): 4908-15, 2006 Aug 15.
Artículo en Inglés | MEDLINE | ID: mdl-16914579

RESUMEN

PURPOSE: The ectopically expressed and deregulated fibroblast growth factor receptor 3 (FGFR3) results from a t(4;14) chromosomal translocation that occurs in approximately 15% of multiple myeloma (MM) patients and confers a particularly poor prognosis. This study assesses the antimyeloma activity of CHIR-258, a small-molecule inhibitor of multiple receptor tyrosine kinases that is currently in phase I trials, in a newly developed FGFR3-driven preclinical MM animal model. EXPERIMENTAL DESIGN: We developed an orthotopic MM model in mice using a luciferase-expressing human KMS-11-luc line that expresses mutant FGFR3 (Y373C). The antimyeloma activity of CHIR-258 was evaluated at doses that inhibited FGFR3 signaling in vivo in this FGFR3-driven animal model. RESULTS: Noninvasive bioluminescence imaging detected MM lesions in nearly all mice injected with KMS-11-luc cells, which were mainly localized in the spine, skull, and pelvis, resulting in frequent development of paralysis. Daily oral administration of CHIR-258 at doses that inhibited FGFR3 signaling in KMS-11-luc tumors in vivo resulted in a significant inhibition of KMS-11-luc tumor growth, which translated into a significant improvement in animal survival. CONCLUSIONS: Our data provide a relevant preclinical basis for clinical trials of CHIR-258 in FGFR3-positive MM patients.


Asunto(s)
Bencimidazoles/farmacología , Mieloma Múltiple/tratamiento farmacológico , Quinolonas/farmacología , Receptor Tipo 3 de Factor de Crecimiento de Fibroblastos/antagonistas & inhibidores , Receptor Tipo 3 de Factor de Crecimiento de Fibroblastos/biosíntesis , Proteínas Adaptadoras Transductoras de Señales/antagonistas & inhibidores , Proteínas Adaptadoras Transductoras de Señales/metabolismo , Animales , Procesos de Crecimiento Celular/efectos de los fármacos , Línea Celular Tumoral , Inhibidores Enzimáticos/farmacología , Humanos , Proteínas de la Membrana/antagonistas & inhibidores , Proteínas de la Membrana/metabolismo , Ratones , Ratones SCID , Proteína Quinasa 1 Activada por Mitógenos/antagonistas & inhibidores , Proteína Quinasa 1 Activada por Mitógenos/metabolismo , Proteína Quinasa 3 Activada por Mitógenos/antagonistas & inhibidores , Proteína Quinasa 3 Activada por Mitógenos/metabolismo , Mieloma Múltiple/enzimología , Fosforilación/efectos de los fármacos , Proteínas Tirosina Quinasas/antagonistas & inhibidores , Receptor Tipo 3 de Factor de Crecimiento de Fibroblastos/sangre , Receptor Tipo 3 de Factor de Crecimiento de Fibroblastos/metabolismo , Ensayos Antitumor por Modelo de Xenoinjerto
3.
Lung Cancer (Auckl) ; 1: 119-140, 2010.
Artículo en Inglés | MEDLINE | ID: mdl-28210112

RESUMEN

Azacitidine (AZA) and decitabine (DAC) are cytidine azanucleoside analogs with clinical activity in myelodysplastic syndromes (MDS) and potential activity in solid tumors. To better understand the mechanism of action of these drugs, we examined the effects of AZA and DAC in a panel of non-small cell lung cancer (NSCLC) cell lines. Of 5 NSCLC lines tested in a cell viability assay, all were sensitive to AZA (EC50 of 1.8-10.5 µM), while only H1299 cells were equally sensitive to DAC (EC50 of 5.1 µM). In the relatively DAC-insensitive cell line A549, both AZA and DAC caused DNA methyltransferase I depletion and DNA hypomethylation; however, only AZA significantly induced markers of DNA damage and apoptosis, suggesting that mechanisms in addition to, or other than, DNA hypomethylation are important for AZA-induced cell death. Cell cycle analysis indicated that AZA induced an accumulation of cells in sub-G1 phase, whereas DAC mainly caused an increase of cells in G2/M. Gene expression analysis of AZA- and DAC-treated cells revealed strikingly different profiles, with many genes distinctly regulated by each drug. In summary, while both AZA and DAC caused DNA hypomethylation, distinct effects were demonstrated on regulation of gene expression, cell cycle, DNA damage, and apoptosis.

4.
PLoS One ; 5(2): e9001, 2010 Feb 02.
Artículo en Inglés | MEDLINE | ID: mdl-20126405

RESUMEN

BACKGROUND: The cytidine nucleoside analogs azacitidine (AZA) and decitabine (DAC) are used for the treatment of patients with myelodysplastic syndromes and acute myeloid leukemia (AML). Few non-clinical studies have directly compared the mechanisms of action of these agents in a head-to-head fashion, and the agents are often viewed as mechanistically similar DNA hypomethylating agents. To better understand the similarities and differences in mechanisms of these drugs, we compared their in vitro effects on several end points in human AML cell lines. METHODOLOGY/PRINCIPAL FINDINGS: Both drugs effected DNA methyltransferase 1 depletion, DNA hypomethylation, and DNA damage induction, with DAC showing equivalent activity at concentrations 2- to 10-fold lower than AZA. At concentrations above 1 microM, AZA had a greater effect than DAC on reducing cell viability. Both drugs increased the sub-G1 fraction and apoptosis markers, with AZA decreasing all cell cycle phases and DAC causing an increase in G2-M. Total protein synthesis was reduced only by AZA, and drug-modulated gene expression profiles were largely non-overlapping. CONCLUSIONS/SIGNIFICANCE: These data demonstrate shared mechanisms of action of AZA and DAC on DNA-mediated markers of activity, but distinctly different effects in their actions on cell viability, protein synthesis, cell cycle, and gene expression. The differential effects of AZA may be mediated by RNA incorporation, as the distribution of AZA in nucleic acid of KG-1a cells was 65:35, RNA:DNA.


Asunto(s)
Apoptosis/efectos de los fármacos , Azacitidina/análogos & derivados , Azacitidina/farmacología , Ciclo Celular/efectos de los fármacos , Biosíntesis de Proteínas/efectos de los fármacos , Enfermedad Aguda , Antimetabolitos Antineoplásicos/farmacología , Western Blotting , Línea Celular , Línea Celular Tumoral , Supervivencia Celular/efectos de los fármacos , Daño del ADN , Metilación de ADN/efectos de los fármacos , Decitabina , Relación Dosis-Respuesta a Droga , Citometría de Flujo , Expresión Génica/efectos de los fármacos , Células HL-60 , Humanos , Leucemia Mieloide/genética , Leucemia Mieloide/metabolismo , Leucemia Mieloide/patología , Análisis de Secuencia por Matrices de Oligonucleótidos/métodos , Proteínas Represoras/antagonistas & inhibidores , Proteínas Represoras/genética , Proteínas Represoras/metabolismo
5.
Antimicrob Agents Chemother ; 50(10): 3260-8, 2006 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-17005803

RESUMEN

The lack of a robust small-animal model for hepatitis C virus (HCV) has hindered the discovery and development of novel drug treatments for HCV infections. We developed a reproducible and easily accessible xenograft mouse efficacy model in which HCV RNA replication is accurately monitored in vivo by real-time, noninvasive whole-body imaging of gamma-irradiated SCID mice implanted with a mouse-adapted luciferase replicon-containing Huh-7 cell line (T7-11). The model was validated by demonstrating that both a small-molecule NS3/4A protease inhibitor (BILN 2061) and human alpha interferon (IFN-alpha) decreased HCV RNA replication and that treatment withdrawal resulted in a rebound in replication, which paralleled clinical outcomes in humans. We further showed that protease inhibitor and IFN-alpha combination therapy was more effective in reducing HCV RNA replication than treatment with each compound alone and supports testing in humans. This robust mouse efficacy model provides a powerful tool for rapid evaluation of potential anti-HCV compounds in vivo as part of aggressive drug discovery efforts.


Asunto(s)
Antivirales/farmacología , Carbamatos/farmacología , Modelos Animales de Enfermedad , Hepacivirus/efectos de los fármacos , Interferón-alfa/farmacología , Compuestos Macrocíclicos/farmacología , Quinolinas/farmacología , Tiazoles/farmacología , Replicación Viral/efectos de los fármacos , Animales , Antivirales/administración & dosificación , Antivirales/uso terapéutico , Carbamatos/administración & dosificación , Carbamatos/uso terapéutico , Línea Celular Tumoral/trasplante , Evaluación Preclínica de Medicamentos , Femenino , Hepatitis C/virología , Humanos , Interferón-alfa/administración & dosificación , Interferón-alfa/uso terapéutico , Compuestos Macrocíclicos/administración & dosificación , Compuestos Macrocíclicos/uso terapéutico , Ratones , Ratones Endogámicos BALB C , Ratones Desnudos , Ratones SCID , Quinolinas/administración & dosificación , Quinolinas/uso terapéutico , Tiazoles/administración & dosificación , Tiazoles/uso terapéutico
6.
Biochem Biophys Res Commun ; 334(4): 1085-91, 2005 Sep 09.
Artículo en Inglés | MEDLINE | ID: mdl-16039993

RESUMEN

Non-receptor proline-rich tyrosine kinase-2 (PYK2), which is activated by phosphorylation of one or more of its tyrosine residues, has been implicated in the regulation of GLUT4 glucose transporter translocation and glucose transport. Some data favor a positive role of PYK2 in stimulating glucose transport, whereas other studies suggest that PYK2 may participate in the induction of insulin resistance. To ascertain the importance of PYK2 in the setting of obesity and insulin resistance, we (1) evaluated the regulation of PYK2 in mice fed a high-fat diet and (2) characterized body and glucose homeostasis in wild type (WT) and PYK2(-/-) mice on different diets. We found that both PYK2 expression and phosphorylation were significantly increased in liver and adipose tissues harvested from high-fat diet fed mice. Wild type and PYK2(-/-) mice were fed a high-fat diet for 8 weeks to induce insulin resistance/obesity. Surprisingly, in response to this diet PYK2(-/-) mice gained significantly more weight than WT mice (18.7+/-1.2g vs. 9.5+/-0.6g). Fasting serum leptin and insulin and blood glucose levels were significantly increased in high-fat diet fed mice irrespective of the presence of PYK2 protein. There was a close correlation between serum leptin and body weight. Intraperitoneal glucose tolerance tests revealed that as expected, the high-fat diet resulted in increased blood glucose levels following glucose administration in wild type mice compared to those fed normal chow. An even greater increase in blood glucose levels was observed in PYK2(-/-) mice compared to wild type mice. These results demonstrate that a lack of PYK2 exacerbates weight gain and development of glucose intolerance/insulin resistance induced by a high-fat diet, suggesting that PYK2 may play a role in slowing the development of obesity, insulin resistance, and/or frank diabetes.


Asunto(s)
Grasas de la Dieta/metabolismo , Glucosa/metabolismo , Resistencia a la Insulina , Obesidad/metabolismo , Proteínas Tirosina Quinasas/metabolismo , Animales , Peso Corporal , Quinasa 2 de Adhesión Focal , Masculino , Ratones , Ratones Endogámicos C57BL , Especificidad de Órganos , Fosforilación , Proteínas Tirosina Quinasas/deficiencia , Distribución Tisular
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA