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1.
Cancer Cell ; 11(1): 53-67, 2007 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-17222790

RESUMO

Neuropilin-1 (NRP1) guides the development of the nervous and vascular systems. Binding to either semaphorins or VEGF, NRP1 acts with plexins to regulate neuronal guidance, or with VEGFR2 to mediate vascular development. We have generated two monoclonal antibodies that bind to the Sema- and VEGF-binding domains of NRP1, respectively. Both antibodies reduce angiogenesis and vascular remodeling, while having little effect on other VEGFR2-mediated events. Importantly, anti-NRP1 antibodies have an additive effect with anti-VEGF therapy in reducing tumor growth. Vessels from tumors treated with anti-VEGF show a close association with pericytes, while tumors treated with both anti-NRP1 and anti-VEGF lack this organization. We propose that blocking NRP1 function inhibits vascular remodeling, rendering vessels more susceptible to anti-VEGF therapy.


Assuntos
Neoplasias Experimentais/irrigação sanguínea , Neovascularização Patológica/metabolismo , Neuropilina-1/imunologia , Fator A de Crescimento do Endotélio Vascular/imunologia , Animais , Anticorpos Monoclonais , Movimento Celular , Células Cultivadas , Células Endoteliais/metabolismo , Feminino , Humanos , Imuno-Histoquímica , Camundongos , Neurônios/metabolismo , Ratos , Semaforina-3A/imunologia
2.
Nature ; 444(7122): 1083-7, 2006 Dec 21.
Artigo em Inglês | MEDLINE | ID: mdl-17183323

RESUMO

Haploinsufficiency of Dll4, a vascular-specific Notch ligand, has shown that it is essential for embryonic vascular development and arteriogenesis. Mechanistically, it is unclear how the Dll4-mediated Notch pathway contributes to complex vascular processes that demand meticulous coordination of multiple signalling pathways. Here we show that Dll4-mediated Notch signalling has a unique role in regulating endothelial cell proliferation and differentiation. Neutralizing Dll4 with a Dll4-selective antibody rendered endothelial cells hyperproliferative, and caused defective cell fate specification or differentiation both in vitro and in vivo. In addition, blocking Dll4 inhibited tumour growth in several tumour models. Remarkably, antibodies against Dll4 and antibodies against vascular endothelial growth factor (VEGF) had paradoxically distinct effects on tumour vasculature. Our data also indicate that Dll4-mediated Notch signalling is crucial during active vascularization, but less important for normal vessel maintenance. Furthermore, unlike blocking Notch signalling globally, neutralizing Dll4 had no discernable impact on intestinal goblet cell differentiation, supporting the idea that Dll4-mediated Notch signalling is largely restricted to the vascular compartment. Therefore, targeting Dll4 might represent a broadly efficacious and well-tolerated approach for the treatment of solid tumours.


Assuntos
Proteínas de Membrana/antagonistas & inibidores , Proteínas de Membrana/metabolismo , Neoplasias/irrigação sanguínea , Neoplasias/patologia , Neovascularização Patológica , Transdução de Sinais , Animais , Diferenciação Celular , Linhagem Celular , Proliferação de Células , Endotélio Vascular/citologia , Homeostase , Humanos , Intestino Delgado/citologia , Intestino Delgado/metabolismo , Peptídeos e Proteínas de Sinalização Intracelular , Camundongos , Receptores Notch/metabolismo , Fator A de Crescimento do Endotélio Vascular/antagonistas & inibidores , Fator A de Crescimento do Endotélio Vascular/metabolismo
3.
J Mol Biol ; 366(3): 815-29, 2007 Feb 23.
Artigo em Inglês | MEDLINE | ID: mdl-17196977

RESUMO

Non-immune (naïve) antibody phage libraries have become an important source of human antibodies. The synthetic phage antibody library described here utilizes a single human framework with a template containing human consensus complementarity-determining regions (CDRs). Diversity of the libraries was introduced at select CDR positions using tailored degenerate and trinucleotide codons that mimic natural human antibodies. Neuropilin-1 (NRP1), a cell-surface receptor for both vascular endothelial growth factor (VEGF) and class 3 semaphorins, is expressed on endothelial cells and neurons. NRP1 is required for vascular development and is expressed widely in the developing vasculature. To investigate the possibility of function blocking antibodies to NRP1 as potential therapeutics, and study the consequence of targeting NRP1 in murine tumor models, panels of antibodies that cross-react with human and murine NRP1 were generated from a designed antibody phage library. Antibody (YW64.3) binds to the CUB domains (a1a2) of NRP1 and completely blocks Sema3A induced neuron collapse; antibody (YW107.4.87) binds to the coagulation factor V/VIII domains (b1b2) of NRP1 and blocks VEGF binding and VEGF induced cell migration. YW107.4.87 inhibits tumor growth in animal xenograft models. These antibodies have provided valuable tools to study the roles of NRP1 in vascular and tumor biology.


Assuntos
Anticorpos Bloqueadores/imunologia , Neuropilina-1/imunologia , Biblioteca de Peptídeos , Sequência de Aminoácidos , Animais , Anticorpos Bloqueadores/química , Afinidade de Anticorpos/efeitos dos fármacos , Células CHO , Movimento Celular/efeitos dos fármacos , Regiões Determinantes de Complementaridade/química , Regiões Determinantes de Complementaridade/imunologia , Cricetinae , Cricetulus , Cones de Crescimento/efeitos dos fármacos , Humanos , Imunoglobulina G/imunologia , Cinética , Camundongos , Modelos Moleculares , Dados de Sequência Molecular , Mutação/genética , Neoplasias/patologia , Estrutura Terciária de Proteína/efeitos dos fármacos , Semaforina-3A/farmacologia
4.
Cancer Res ; 66(5): 2639-49, 2006 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-16510583

RESUMO

Tumor blood vessels normalized by antiangiogenic therapy may provide improved delivery of chemotherapeutic agents during a window of time but it is unknown how protein expression in tumor vascular endothelial cells changes. We evaluated the distribution of RGD-4C phage, which binds alpha(v)beta(3), alpha(v)beta(5), and alpha(5)beta(1) integrins on tumor blood vessels before and after antiangiogenic therapy. Unlike the control phage, fd-tet, RGD-4C phage homed to vascular endothelial cells in spontaneous tumors in RIP-Tag2 transgenic mice in a dose-dependent fashion. The distribution of phage was similar to alpha(v)beta(3) and alpha(5)beta(1) integrin expression. Blood vessels that survived treatment with AG-013736, a small molecule inhibitor of vascular endothelial growth factor and platelet-derived growth factor receptors, had only 4% as much binding of RGD-4C phage compared with vessels in untreated tumors. Cellular distribution of RGD-4C phage in surviving tumor vessels matched the alpha(5)beta(1) integrin expression. The reduction in integrin expression on tumor vessels after antiangiogenic therapy raises the possibility that integrin-targeted delivery of diagnostics or therapeutics may be compromised. Efficacious delivery of drugs may benefit from identification by in vivo phage display of targeting peptides that bind to tumor blood vessels normalized by antiangiogenic agents.


Assuntos
Adenoma de Células das Ilhotas Pancreáticas/irrigação sanguínea , Bacteriófago M13/metabolismo , Células Endoteliais/virologia , Imidazóis/farmacologia , Indazóis/farmacologia , Integrina alfa5beta1/biossíntese , Integrina alfaVbeta3/biossíntese , Neoplasias Pancreáticas/irrigação sanguínea , Adenoma de Células das Ilhotas Pancreáticas/terapia , Animais , Axitinibe , Bacteriófago M13/genética , Células Endoteliais/efeitos dos fármacos , Células Endoteliais/metabolismo , Feminino , Integrina alfa5beta1/antagonistas & inibidores , Integrina alfaVbeta3/antagonistas & inibidores , Masculino , Camundongos , Camundongos Transgênicos , Microscopia de Fluorescência , Neovascularização Patológica/tratamento farmacológico , Neovascularização Patológica/metabolismo , Neovascularização Patológica/virologia , Oligopeptídeos/genética , Neoplasias Pancreáticas/terapia , Especificidade por Substrato
5.
Oncotarget ; 7(36): 57525-57544, 2016 09 06.
Artigo em Inglês | MEDLINE | ID: mdl-27438153

RESUMO

MYC oncoproteins deliver a potent oncogenic stimulus in several human cancers, making them major targets for drug development, but efforts to deliver clinically practical therapeutics have not yet been realized. In childhood cancer, aberrant expression of MYC and MYCN genes delineates a group of aggressive tumours responsible for a major proportion of pediatric cancer deaths. We designed a chemical-genetic screen that identifies compounds capable of enhancing proteasomal elimination of MYCN oncoprotein. We isolated several classes of compound that selectively kill MYCN expressing cells and we focus on inhibitors of PI3K/mTOR pathway in this study. We show that PI3K/mTOR inhibitors selectively killed MYCN-expressing neuroblastoma tumor cells, and induced significant apoptosis of transgenic MYCN-driven neuroblastoma tumors concomitant with elimination of MYCN protein in vivo. Mechanistically, the ability of these compounds to degrade MYCN requires complete blockade of mTOR but not PI3 kinase activity and we highlight NVP-BEZ235 as a PI3K/mTOR inhibitor with an ideal activity profile. These data establish that MYCN expression is a marker indicative of likely clinical sensitivity to mTOR inhibition, and provide a rationale for the selection of clinical candidate MYCN-destabilizers likely to be useful for the treatment of MYCN-driven cancers.


Assuntos
Proteína Proto-Oncogênica N-Myc/genética , Proteína Proto-Oncogênica N-Myc/metabolismo , Neuroblastoma/tratamento farmacológico , Serina-Treonina Quinases TOR/antagonistas & inibidores , Animais , Apoptose , Linhagem Celular Tumoral , Regulação Neoplásica da Expressão Gênica , Glicogênio Sintase Quinase 3 beta/metabolismo , Células HEK293 , Humanos , Imidazóis/química , Alvo Mecanístico do Complexo 1 de Rapamicina/metabolismo , Alvo Mecanístico do Complexo 2 de Rapamicina/metabolismo , Camundongos , Camundongos Nus , Camundongos Transgênicos , Transplante de Neoplasias , Neuroblastoma/genética , Fosfatidilinositol 3-Quinases/metabolismo , Fosforilação , Quinolinas/química , Transdução de Sinais , Transgenes
6.
Front Oncol ; 5: 111, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26029667

RESUMO

The MYCN proto-oncogene is associated with poor outcome across a broad range of pediatric tumors. While amplification of MYCN drives subsets of high-risk neuroblastoma and medulloblastoma, dysregulation of MYCN in medulloblastoma (in the absence of amplification) also contributes to pathogenesis. Since PI3K stabilizes MYCN, we have used inhibitors of PI3K to drive degradation. In this study, we show PI3K inhibitors by themselves induce cell cycle arrest, with modest induction of apoptosis. In screening inhibitors of PI3K against MYCN, we identified PIK-75 and its derivative, PW-12, inhibitors of both PI3K and of protein kinases, to be highly effective in destabilizing MYCN. To determine the effects of PW-12 treatment in vivo, we analyzed a genetically engineered mouse model for MYCN-driven neuroblastoma and a model of MYCN-driven medulloblastoma. PW-12 showed significant activity in both models, inducing vascular collapse and regression of medulloblastoma with prominent apoptosis in both models. These results demonstrate that inhibitors of lipid and protein kinases can drive apoptosis in MYCN-driven cancers and support the importance of MYCN as a therapeutic target.

7.
Mol Cancer Ther ; 14(2): 419-28, 2015 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-25522764

RESUMO

Glioblastoma (GBM) is the most common malignant primary brain tumor. Radiotherapy fails to eliminate subpopulations of stem-like tumor-propagating cells (TPC), resulting in tumor regrowth. To identify kinases that promote TPC self-renewal rather than increasing proliferation in human GBM cultures, we screened a library of 54 nonselective tool compounds and determined their kinase inhibitor profiles in vitro. Most compounds inhibited aurora kinase (AURK) activity and blocked TPC self-renewal, while inducing GBM cell polynucleation and apoptosis. To prevent regrowth by TPCs, we used a priming dose of radiation followed by incubation with the pan-AURK inhibitor VX680 to block self-renewal and induce apoptosis in GBM cultures. In mice xenografted with human GBM cells, radiotherapy followed by VX680 treatment resulted in reduced tumor growth and increased survival relative to either monotherapy alone or VX680 treatment before radiation. Our results indicate that AURK inhibition, subsequent to radiation, may enhance the efficacy of radiotherapy by targeting radioresistant TPCs in human GBMs.


Assuntos
Aurora Quinases/antagonistas & inibidores , Neoplasias Encefálicas/tratamento farmacológico , Neoplasias Encefálicas/radioterapia , Glioblastoma/tratamento farmacológico , Glioblastoma/radioterapia , Células-Tronco Neoplásicas/patologia , Inibidores de Proteínas Quinases/uso terapêutico , Animais , Apoptose/efeitos dos fármacos , Aurora Quinases/metabolismo , Biomarcadores Tumorais/metabolismo , Neoplasias Encefálicas/patologia , Pontos de Checagem do Ciclo Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Ensaios de Seleção de Medicamentos Antitumorais , Glioblastoma/patologia , Histonas/metabolismo , Humanos , Glicoproteínas de Membrana/metabolismo , Camundongos Nus , Células-Tronco Neoplásicas/efeitos dos fármacos , Fosforilação/efeitos dos fármacos , Inibidores de Proteínas Quinases/farmacologia , Tolerância a Radiação/efeitos dos fármacos , Ensaios Antitumorais Modelo de Xenoenxerto
8.
Cancer Discov ; 3(3): 308-23, 2013 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-23430699

RESUMO

Bromodomain inhibition comprises a promising therapeutic strategy in cancer, particularly for hematologic malignancies. To date, however, genomic biomarkers to direct clinical translation have been lacking. We conducted a cell-based screen of genetically defined cancer cell lines using a prototypical inhibitor of BET bromodomains. Integration of genetic features with chemosensitivity data revealed a robust correlation between MYCN amplification and sensitivity to bromodomain inhibition. We characterized the mechanistic and translational significance of this finding in neuroblastoma, a childhood cancer with frequent amplification of MYCN. Genome-wide expression analysis showed downregulation of the MYCN transcriptional program accompanied by suppression of MYCN transcription. Functionally, bromodomain-mediated inhibition of MYCN impaired growth and induced apoptosis in neuroblastoma. BRD4 knockdown phenocopied these effects, establishing BET bromodomains as transcriptional regulators of MYCN. BET inhibition conferred a significant survival advantage in 3 in vivo neuroblastoma models, providing a compelling rationale for developing BET bromodomain inhibitors in patients with neuroblastoma.


Assuntos
Neuroblastoma/tratamento farmacológico , Proteínas Nucleares/antagonistas & inibidores , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Proteínas Oncogênicas/genética , Fatores de Transcrição/antagonistas & inibidores , Fatores de Transcrição/metabolismo , Animais , Apoptose/efeitos dos fármacos , Apoptose/genética , Azepinas/farmacologia , Pontos de Checagem do Ciclo Celular/efeitos dos fármacos , Pontos de Checagem do Ciclo Celular/genética , Proteínas de Ciclo Celular , Processos de Crescimento Celular/genética , Linhagem Celular Tumoral , Criança , Regulação para Baixo/efeitos dos fármacos , Feminino , Amplificação de Genes , Humanos , Camundongos , Terapia de Alvo Molecular , Proteína Proto-Oncogênica N-Myc , Neuroblastoma/genética , Neuroblastoma/metabolismo , Neuroblastoma/patologia , Proteínas Nucleares/deficiência , Proteínas Oncogênicas/metabolismo , Regiões Promotoras Genéticas , Estrutura Terciária de Proteína , Proteínas Proto-Oncogênicas c-myc/genética , RNA Interferente Pequeno/administração & dosagem , RNA Interferente Pequeno/genética , Fatores de Transcrição/deficiência , Fatores de Transcrição/genética , Transfecção , Triazóis/farmacologia , Ensaios Antitumorais Modelo de Xenoenxerto
9.
Sci Transl Med ; 4(115): 115ra3, 2012 Jan 04.
Artigo em Inglês | MEDLINE | ID: mdl-22218692

RESUMO

Neuroblastoma, a tumor of peripheral neural crest origin, numbers among the most common childhood cancers. Both amplification of the proto-oncogene MYCN and increased neoangiogenesis mark high-risk disease. Because angiogenesis is regulated by phosphatidylinositol 3-kinase (PI3K), we tested a clinical PI3K inhibitor, NVP-BEZ235, in MYCN-dependent neuroblastoma. NVP-BEZ235 decreased angiogenesis and improved survival in both primary human (highly pretreated recurrent MYCN-amplified orthotopic xenograft) and transgenic mouse models for MYCN-driven neuroblastoma. Using both gain- and loss-of-function approaches, we demonstrated that the antiangiogenic efficacy of NVP-BEZ235 depended critically on MYCN in vitro and in vivo. Thus, clinical PI3K/mammalian target of rapamycin inhibitors drove degradation of MYCN in tumor cells, with secondary paracrine blockade of angiogenesis. Our data demonstrated significantly improved survival in treated animals and suggest that NVP-BEZ235 should be tested in children with high-risk, MYCN-amplified neuroblastoma.


Assuntos
Neoplasias Encefálicas/metabolismo , Regulação Neoplásica da Expressão Gênica , Neuroblastoma/metabolismo , Proteínas Nucleares/biossíntese , Proteínas Oncogênicas/biossíntese , Proteínas Proto-Oncogênicas/biossíntese , Inibidores da Angiogênese/farmacologia , Animais , Linhagem Celular Tumoral , Células Endoteliais da Veia Umbilical Humana , Humanos , Imidazóis/farmacologia , Camundongos , Camundongos Transgênicos , Proteína Proto-Oncogênica N-Myc , Transplante de Neoplasias , Neovascularização Patológica , Comunicação Parácrina , Fosfatidilinositol 3-Quinases/metabolismo , Proto-Oncogene Mas , Quinolinas/farmacologia , Transdução de Sinais
10.
Nat Med ; 16(10): 1134-40, 2010 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-20871609

RESUMO

Inactivation of the p53 tumor suppressor pathway allows cell survival in times of stress and occurs in many human cancers; however, normal embryonic stem cells and some cancers such as neuroblastoma maintain wild-type human TP53 and mouse Trp53 (referred to collectively as p53 herein). Here we describe a miRNA, miR-380-5p, that represses p53 expression via a conserved sequence in the p53 3' untranslated region (UTR). miR-380-5p is highly expressed in mouse embryonic stem cells and neuroblastomas, and high expression correlates with poor outcome in neuroblastomas with neuroblastoma derived v-myc myelocytomatosis viral-related oncogene (MYCN) amplification. miR-380 overexpression cooperates with activated HRAS oncoprotein to transform primary cells, block oncogene-induced senescence and form tumors in mice. Conversely, inhibition of endogenous miR-380-5p in embryonic stem or neuroblastoma cells results in induction of p53, and extensive apoptotic cell death. In vivo delivery of a miR-380-5p antagonist decreases tumor size in an orthotopic mouse model of neuroblastoma. We demonstrate a new mechanism of p53 regulation in cancer and stem cells and uncover a potential therapeutic target for neuroblastoma.


Assuntos
Amplificação de Genes , MicroRNAs/fisiologia , Neuroblastoma/patologia , Proteínas Nucleares/genética , Proteínas Oncogênicas/genética , Proteína Supressora de Tumor p53/antagonistas & inibidores , Regiões 3' não Traduzidas , Animais , Apoptose , Sítios de Ligação , Dano ao DNA , Feminino , Humanos , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Transgênicos , Proteína Proto-Oncogênica N-Myc , Neuroblastoma/genética , Oncogenes , Proteína Supressora de Tumor p53/fisiologia
11.
Cancer ; 104(10): 2104-15, 2005 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-16208706

RESUMO

BACKGROUND: Previous studies of the TRansgenic Adenocarcinoma of the Mouse Prostate (TRAMP) model vasculature suggest that, as tumors develop, vessels invade the glandular epithelium. However, changes in the vasculature are difficult to study in conventional thin tissue sections. The authors used a new approach to characterize morphologic and architectural changes of blood vessels and pericytes during tumor development in TRAMP mice. METHODS: Eighty-micron cryostat sections of normal prostate and three histopathologic stages of TRAMP tumor sections, classified by epithelial cell E-cadherin immunoreactivity, were immunostained with vascular endothelial cell and pericyte receptor antibodies and evaluated by confocal microscopy. RESULTS: In the normal mouse prostate, capillaries were most abundant in the fibromuscular tunica between the epithelium and smooth muscle of the ductules. In the prostatic intraepithelial neoplasia (PIN) stage, vessels accompanied epithelial cell protrusions into the ductule lumen but remained in the connective tissue at the basal side of the epithelium. Well differentiated tissues had extensive angiogenesis with five times the normal mean vascularity outside ductules. Vessels were of variable diameter, were associated with an increased number of pericytes, and some had endothelial sprouts. Angiogenic blood vessels from poorly differentiated adenocarcinomas were tortuous, variable in caliber, and lacked the normal hierarchy. Pericytes on these vessels had an abnormal phenotype manifested by alpha-smooth muscle actin expression and loose association with endothelial cells. Angiogenesis and loss of vascular hierarchy were also found in human prostate carcinoma. CONCLUSIONS: Vascular abnormalities, which begin at the PIN stage and intensify in well differentiated and poorly differentiated tumors, may be useful readouts for early detection and treatment assessment in prostate carcinoma.


Assuntos
Adenocarcinoma/irrigação sanguínea , Neovascularização Patológica , Pericitos/patologia , Neoplasia Prostática Intraepitelial/irrigação sanguínea , Neoplasias da Próstata/irrigação sanguínea , Adenocarcinoma/metabolismo , Animais , Caderinas/metabolismo , Modelos Animais de Doenças , Humanos , Imuno-Histoquímica , Masculino , Camundongos , Camundongos Transgênicos , Microscopia Confocal , Pericitos/metabolismo , Neoplasia Prostática Intraepitelial/metabolismo , Neoplasias da Próstata/metabolismo , Ratos
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