Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 11 de 11
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Blood ; 112(3): 875-85, 2008 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-18480424

RESUMO

In beta-thalassemia, the mechanism driving ineffective erythropoiesis (IE) is insufficiently understood. We analyzed mice affected by beta-thalassemia and observed, unexpectedly, a relatively small increase in apoptosis of their erythroid cells compared with healthy mice. Therefore, we sought to determine whether IE could also be characterized by limited erythroid cell differentiation. In thalassemic mice, we observed that a greater than normal percentage of erythroid cells was in S-phase, exhibiting an erythroblast-like morphology. Thalassemic cells were associated with expression of cell cycle-promoting genes such as EpoR, Jak2, Cyclin-A, Cdk2, and Ki-67 and the antiapoptotic protein Bcl-X(L). The cells also differentiated less than normal erythroid ones in vitro. To investigate whether Jak2 could be responsible for the limited cell differentiation, we administered a Jak2 inhibitor, TG101209, to healthy and thalassemic mice. Exposure to TG101209 dramatically decreased the spleen size but also affected anemia. Although our data do not exclude a role for apoptosis in IE, we propose that expansion of the erythroid pool followed by limited cell differentiation exacerbates IE in thalassemia. In addition, these results suggest that use of Jak2 inhibitors has the potential to profoundly change the management of this disorder.


Assuntos
Diferenciação Celular , Células Eritroides/patologia , Eritropoese , Janus Quinase 2/genética , Talassemia beta/sangue , Animais , Apoptose , Quinases Ciclina-Dependentes/genética , Janus Quinase 2/antagonistas & inibidores , Camundongos , Baço/patologia
2.
Cancer Cell ; 13(4): 311-20, 2008 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-18394554

RESUMO

We report that TG101348, a selective small-molecule inhibitor of JAK2 with an in vitro IC50 of approximately 3 nM, shows therapeutic efficacy in a murine model of myeloproliferative disease induced by the JAK2V617F mutation. In treated animals, there was a statistically significant reduction in hematocrit and leukocyte count, a dose-dependent reduction/elimination of extramedullary hematopoiesis, and, at least in some instances, evidence for attenuation of myelofibrosis. There were no apparent toxicities and no effect on T cell number. In vivo responses were correlated with surrogate endpoints, including reduction/elimination of JAK2V617F disease burden assessed by quantitative genomic PCR, suppression of endogenous erythroid colony formation, and in vivo inhibition of JAK-STAT signal transduction as assessed by flow cytometric measurement of phosphorylated Stat5.


Assuntos
Substituição de Aminoácidos , Modelos Animais de Doenças , Janus Quinase 2/antagonistas & inibidores , Janus Quinase 2/genética , Policitemia Vera/tratamento farmacológico , Policitemia Vera/enzimologia , Inibidores de Proteínas Quinases/uso terapêutico , Pirrolidinas/uso terapêutico , Sulfonamidas/uso terapêutico , Animais , Transplante de Medula Óssea , Linhagem Celular Tumoral , Ensaio de Unidades Formadoras de Colônias , Determinação de Ponto Final , Citometria de Fluxo , Sistema Hematopoético/citologia , Sistema Hematopoético/efeitos dos fármacos , Humanos , Janus Quinase 2/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Fenilalanina/genética , Inibidores de Proteínas Quinases/farmacocinética , Inibidores de Proteínas Quinases/farmacologia , Pirrolidinas/farmacocinética , Transdução de Sinais/efeitos dos fármacos , Sulfonamidas/farmacocinética , Taxa de Sobrevida , Resultado do Tratamento , Valina/genética
3.
Cancer Cell ; 13(4): 321-30, 2008 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-18394555

RESUMO

Polycythemia Vera (PV) is a myeloproliferative disorder (MPD) that is commonly characterized by mutant JAK2 (JAK2V617F) signaling, erythrocyte overproduction, and a propensity for thrombosis, progression to myelofibrosis, or acute leukemia. In this study, JAK2V617F expression by human hematopoietic progenitors promoted erythroid colony formation and erythroid engraftment in a bioluminescent xenogeneic immunocompromised mouse transplantation model. A selective JAK2 inhibitor, TG101348 (300 nM), significantly inhibited JAK2V617F+ progenitor-derived colony formation as well as engraftment (120 mg/kg) in xenogeneic transplantation studies. TG101348 treatment decreased GATA-1 expression, which is associated with erythroid-skewing of JAK2V617F+ progenitor differentiation, and inhibited STAT5 as well as GATA S310 phosphorylation. Thus, TG101348 may be an effective inhibitor of JAK2V617F+ MPDs in clinical trials.


Assuntos
Diferenciação Celular/efeitos dos fármacos , Células Precursoras Eritroides/enzimologia , Células Precursoras Eritroides/patologia , Janus Quinase 2/antagonistas & inibidores , Policitemia Vera/enzimologia , Policitemia Vera/patologia , Inibidores de Proteínas Quinases/farmacologia , Adulto , Idoso , Substituição de Aminoácidos , Animais , Sequência de Bases , Células Precursoras Eritroides/efeitos dos fármacos , Feminino , Humanos , Janus Quinase 2/genética , Masculino , Camundongos , Pessoa de Meia-Idade , Dados de Sequência Molecular , Fenilalanina/genética , Inibidores de Proteínas Quinases/química , Transdução de Sinais/efeitos dos fármacos , Transplante de Células-Tronco , Valina/genética
4.
J Med Chem ; 51(6): 1546-59, 2008 Mar 27.
Artigo em Inglês | MEDLINE | ID: mdl-18311895

RESUMO

Age-related macular degeneration (AMD) is one of the leading causes of loss of vision in the industrialized world. Attenuating the VEGF signal in the eye to treat AMD has been validated clinically. A large body of evidence suggests that inhibitors targeting the VEGFr pathway may be effective for the treatment of AMD. Recent studies using Src/YES knockout mice suggest that along with VEGF, Src and YES play a crucial role in vascular leak and might be useful in treating edema associated with AMD. Therefore, we have developed several potent benzotriazine inhibitors designed to target VEGFr2, Src, and YES. One of the most potent compounds is 4-chloro-3-{5-methyl-3-[4-(2-pyrrolidin-1-yl-ethoxy)phenylamino]benzo[1,2,4]triazin-7-yl}phenol ( 5), a dual inhibitor of both VEGFr2 and the Src family (Src and YES) kinases. Several ester analogues of 5 were prepared as prodrugs to improve the concentration of 5 at the back of the eye after topical administration. The thermal stability of these esters was studied, and it was found that benzoyl and substituted benzoyl esters of 5 showed good thermal stability. The hydrolysis rates of these prodrugs were studied to analyze their ability to undergo conversion to 5 in vivo so that appropriate concentrations of 5 are available in the back-of-the-eye tissues. From these studies, we identified 4-chloro-3-(5-methyl-3-{[4-(2-pyrrolidin-1-ylethoxy)phenyl]amino}-1,2,4-benzotriazin-7-yl)phenyl benzoate ( 12), a topically administered prodrug delivered as an eye drop that is readily converted to the active compound 5 in the eye. This topically delivered compound exhibited excellent ocular pharmacokinetics and poor systemic circulation and showed good efficacy in the laser induced choroidal neovascularization model. On the basis of its superior profile, compound 12 was advanced. It is currently in a clinical trial as a first in class, VEGFr2 targeting, topically applied compound for the treatment of AMD.


Assuntos
Degeneração Macular/tratamento farmacológico , Soluções Oftálmicas/uso terapêutico , Fenóis/uso terapêutico , Pró-Fármacos/uso terapêutico , Triazinas/uso terapêutico , Administração Tópica , Animais , Neovascularização de Coroide/tratamento farmacológico , Ensaios Clínicos como Assunto , Modelos Animais de Doenças , Relação Dose-Resposta a Droga , Desenho de Fármacos , Olho/efeitos dos fármacos , Olho/efeitos da radiação , Lasers , Camundongos , Camundongos Knockout , Modelos Moleculares , Estrutura Molecular , Soluções Oftálmicas/química , Soluções Oftálmicas/farmacocinética , Fenóis/química , Fenóis/farmacocinética , Pró-Fármacos/química , Pró-Fármacos/farmacocinética , Relação Estrutura-Atividade , Triazinas/química , Triazinas/farmacocinética , Receptor 2 de Fatores de Crescimento do Endotélio Vascular/antagonistas & inibidores , Quinases da Família src/antagonistas & inibidores
5.
Bioorg Med Chem Lett ; 17(3): 602-8, 2007 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-17113292
6.
J Cell Biol ; 162(5): 933-43, 2003 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-12952943

RESUMO

Antagonists of alphavbeta3 and alphavbeta5 disrupt angiogenesis in response to bFGF and VEGF, respectively. Here, we show that these alphav integrins differentially contribute to sustained Ras-extracellular signal-related kinase (Ras-ERK) signaling in blood vessels, a requirement for endothelial cell survival and angiogenesis. Inhibition of FAK or alphavbeta5 disrupted VEGF-mediated Ras and c-Raf activity on the chick chorioallantoic membrane, whereas blockade of FAK or integrin alphavbeta3 had no effect on bFGF-mediated Ras activity, but did suppress c-Raf activation. Furthermore, retroviral delivery of active Ras or c-Raf promoted ERK activity and angiogenesis, which anti-alphavbeta5 blocked upstream of Ras, whereas anti-alphavbeta3 blocked downstream of Ras, but upstream of c-Raf. The activation of c-Raf by bFGF/alphavbeta3 not only depended on FAK, but also required p21-activated kinase-dependent phosphorylation of serine 338 on c-Raf, whereas VEGF-mediated c-Raf phosphorylation/activation depended on Src, but not Pak. Thus, integrins alphavbeta3 and alphavbeta5 differentially regulate the Ras-ERK pathway, accounting for distinct vascular responses during two pathways of angiogenesis.


Assuntos
Integrina alfaVbeta3/metabolismo , Integrinas/metabolismo , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Neovascularização Fisiológica , Receptores de Vitronectina/metabolismo , Proteínas ras/metabolismo , Animais , Embrião de Galinha , Ativação Enzimática , Fator 2 de Crescimento de Fibroblastos/metabolismo , Proteína-Tirosina Quinases de Adesão Focal , Integrina alfaVbeta3/antagonistas & inibidores , Integrinas/antagonistas & inibidores , Proteínas Serina-Treonina Quinases/metabolismo , Proteínas Tirosina Quinases/metabolismo , Proteínas Proto-Oncogênicas c-raf/metabolismo , Receptores de Vitronectina/antagonistas & inibidores , Transdução de Sinais/fisiologia , Fator A de Crescimento do Endotélio Vascular/metabolismo , Quinases Ativadas por p21 , Quinases da Família src/metabolismo
8.
Science ; 301(5629): 94-6, 2003 Jul 04.
Artigo em Inglês | MEDLINE | ID: mdl-12843393

RESUMO

Raf kinases have been linked to endothelial cell survival. Here, we show that basic fibroblast growth factor (bFGF) and vascular endothelial growth factor (VEGF) differentially activate Raf, resulting in protection from distinct pathways of apoptosis in human endothelial cells and chick embryo vasculature. bFGF activated Raf-1 via p21-activated protein kinase-1 (PAK-1) phosphorylation of serines 338 and 339, resulting in Raf-1 mitochondrial translocation and endothelial cell protection from the intrinsic pathway of apoptosis, independent of the mitogen-activated protein kinase kinase-1 (MEK1). In contrast, VEGF activated Raf-1 via Src kinase, leading to phosphorylation of tyrosines 340 and 341 and MEK1-dependent protection from extrinsic-mediated apoptosis. These findings implicate Raf-1 as a pivotal regulator of endothelial cell survival during angiogenesis.


Assuntos
Apoptose , Endotélio Vascular/citologia , Neovascularização Fisiológica , Proteínas Proto-Oncogênicas c-raf/metabolismo , Animais , Sobrevivência Celular , Células Cultivadas , Embrião de Galinha , Fatores de Crescimento Endotelial/farmacologia , Endotélio Vascular/efeitos dos fármacos , Ativação Enzimática , Inibidores Enzimáticos/farmacologia , Fator 2 de Crescimento de Fibroblastos/farmacologia , Flavonoides/farmacologia , Humanos , Peptídeos e Proteínas de Sinalização Intercelular/farmacologia , Linfocinas/farmacologia , MAP Quinase Quinase 1 , Mitocôndrias/metabolismo , Proteína Quinase 1 Ativada por Mitógeno/metabolismo , Proteína Quinase 3 Ativada por Mitógeno , Quinases de Proteína Quinase Ativadas por Mitógeno/antagonistas & inibidores , Quinases de Proteína Quinase Ativadas por Mitógeno/metabolismo , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Neovascularização Patológica , Neovascularização Fisiológica/efeitos dos fármacos , Fosforilação , Mutação Puntual , Proteínas Serina-Treonina Quinases/antagonistas & inibidores , Proteínas Serina-Treonina Quinases/metabolismo , Transporte Proteico , Proteínas Proto-Oncogênicas B-raf , Proteínas Proto-Oncogênicas c-raf/química , Proteínas Proto-Oncogênicas c-raf/genética , Transdução de Sinais , Veias Umbilicais , Fator A de Crescimento do Endotélio Vascular , Fatores de Crescimento do Endotélio Vascular , Quinases Ativadas por p21 , Quinases da Família src/antagonistas & inibidores , Quinases da Família src/metabolismo
9.
Science ; 296(5577): 2404-7, 2002 Jun 28.
Artigo em Inglês | MEDLINE | ID: mdl-12089446

RESUMO

Efforts to influence the biology of blood vessels by gene delivery have been hampered by a lack of targeting vectors specific for endothelial cells in diseased tissues. Here we show that a cationic nanoparticle (NP) coupled to an integrin alphavbeta3-targeting ligand can deliver genes selectively to angiogenic blood vessels in tumor-bearing mice. The therapeutic efficacy of this approach was tested by generating NPs conjugated to a mutant Raf gene, ATPmu-Raf, which blocks endothelial signaling and angiogenesis in response to multiple growth factors. Systemic injection of the NP into mice resulted in apoptosis of the tumor-associated endothelium, ultimately leading to tumor cell apoptosis and sustained regression of established primary and metastatic tumors.


Assuntos
Terapia Genética/métodos , Nanotecnologia , Neoplasias Experimentais/terapia , Neovascularização Patológica/terapia , Proteínas Proto-Oncogênicas c-raf/genética , Receptores de Vitronectina/metabolismo , Trifosfato de Adenosina/metabolismo , Animais , Apoptose , Cátions , Endotélio Vascular/citologia , Endotélio Vascular/metabolismo , Endotélio Vascular/patologia , Marcação de Genes , Técnicas de Transferência de Genes , Vetores Genéticos , Humanos , Marcação In Situ das Extremidades Cortadas , Ligantes , Lipídeos , Melanoma Experimental/irrigação sanguínea , Melanoma Experimental/patologia , Melanoma Experimental/terapia , Camundongos , Camundongos Endogâmicos BALB C , Mutação , Metástase Neoplásica , Transplante de Neoplasias , Neoplasias Experimentais/irrigação sanguínea , Neoplasias Experimentais/patologia , Neovascularização Patológica/patologia , Proteínas Proto-Oncogênicas c-raf/metabolismo , Distribuição Aleatória , Células Tumorais Cultivadas
10.
J Cell Biol ; 157(1): 149-60, 2002 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-11927607

RESUMO

Vascular endothelial growth factor (VEGF) promotes vascular permeability (VP) and neovascularization, and is required for development. We find that VEGF-stimulated Src activity in chick embryo blood vessels induces the coupling of focal adhesion kinase (FAK) to integrin alpha(v)beta5, a critical event in VEGF-mediated signaling and biological responsiveness. In contrast, FAK is constitutively associated with beta1 and beta3 integrins in the presence or absence of growth factors. In cultured endothelial cells, VEGF, but not basic fibroblast growth factor, promotes the Src-mediated phosphorylation of FAK on tyrosine 861, which contributes to the formation of a FAK/alpha(v)beta5 signaling complex. Moreover, formation of this FAK/alpha(v)beta5 complex is significantly reduced in pp60c-src-deficient mice. Supporting these results, mice deficient in either pp60c-src or integrin beta5, but not integrin beta3, have a reduced VP response to VEGF. This FAK/alpha(v)beta5 complex was also detected in epidermal growth factor-stimulated epithelial cells, suggesting a function for this complex outside the endothelium. Our findings indicate that Src can coordinate specific growth factor and extracellular matrix inputs by recruiting integrin alpha(v)beta5 into a FAK-containing signaling complex during growth factor-mediated biological responses.


Assuntos
Fatores de Crescimento Endotelial/farmacologia , Integrinas/metabolismo , Linfocinas/farmacologia , Proteínas Tirosina Quinases/metabolismo , Receptores de Vitronectina , Transdução de Sinais/fisiologia , Quinases da Família src/metabolismo , Sequência de Aminoácidos , Animais , Células Cultivadas , Embrião de Galinha , Córion/citologia , Córion/enzimologia , Endotélio Vascular/citologia , Endotélio Vascular/embriologia , Endotélio Vascular/enzimologia , Quinase 1 de Adesão Focal , Proteína-Tirosina Quinases de Adesão Focal , Humanos , Integrinas/genética , Rim/citologia , Camundongos , Camundongos Knockout , Dados de Sequência Molecular , Neovascularização Fisiológica/fisiologia , Fosforilação , Estrutura Terciária de Proteína , Proteínas Tirosina Quinases/química , Coelhos , Transdução de Sinais/efeitos dos fármacos , Tirosina/metabolismo , Veias Umbilicais/citologia , Fator A de Crescimento do Endotélio Vascular , Fatores de Crescimento do Endotélio Vascular , Quinases da Família src/genética
11.
Nat Rev Cancer ; 2(2): 91-100, 2002 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-12635172

RESUMO

As cancer cells undergo metastasis--invasion and migration of a new tissue--they penetrate and attach to the target tissue's basal matrix. This allows the cancer cell to pull itself forward into the tissue. The attachment is mediated by cell-surface receptors known as integrins, which bind to components of the extracellular matrix. Integrins are crucial for cell invasion and migration, not only for physically tethering cells to the matrix, but also for sending and receiving molecular signals that regulate these processes.


Assuntos
Movimento Celular , Integrinas/metabolismo , Invasividade Neoplásica/patologia , Metástase Neoplásica/patologia , Animais , Apoptose , Membrana Basal/patologia , Sobrevivência Celular , Ensaios Clínicos como Assunto , Matriz Extracelular/metabolismo , Humanos , Integrinas/antagonistas & inibidores , Transdução de Sinais
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...