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1.
Oncogene ; 32(42): 5048-57, 2013 Oct 17.
Artigo em Inglês | MEDLINE | ID: mdl-23246962

RESUMO

Hypoxia is linked to epithelial-mesenchymal transition (EMT) and tumor progression in numerous carcinomas. Responses to hypoxia are thought to operate via hypoxia-inducible factors (HIFs), but the importance of co-factors that regulate HIF signaling within tumors is not well understood. Here, we elucidate a signaling pathway that physically and functionally couples tyrosine phosphorylation of ß-catenin to HIF1α signaling and HIF1α-mediated tumor EMT. Primary human lung adenocarcinomas accumulate pY654-ß-catenin and HIF1α. All pY654-ß-catenin, and only the tyrosine phosphorylated form, was found complexed with HIF1α and active Src, both within the human tumors and in lung tumor cell lines exposed to hypoxia. Phosphorylation of Y654, generated by hypoxia mediated, reactive oxygen species (ROS)-dependent Src kinase activation, was required for ß-catenin to interact with HIF1α and Src, to promote HIF1α transcriptional activity, and for hypoxia-induced EMT. Mice bearing hypoxic pancreatic islet adenomas, generated by treatment with anti-vascular endothelial growth factor antibodies, accumulate HIF1α/pY654-ß-catenin complexes and develop an invasive phenotype. Concurrent administration of the ROS inhibitor N-acetylcysteine abrogated ß-catenin/HIF pathway activity and restored adenoma architecture. Collectively, the findings implicate accumulation of pY654-ß-catenin specifically complexed to HIF1α and Src kinase as critically involved in HIF1α signaling and tumor invasion. The findings also suggest that targeting ROS-dependent aspects of the pY654-ß-catenin/ HIF1α pathway may attenuate untoward biological effects of anti-angiogenic agents and tumor hypoxia.


Assuntos
Adenocarcinoma/metabolismo , Subunidade alfa do Fator 1 Induzível por Hipóxia/metabolismo , Neoplasias Pulmonares/metabolismo , beta Catenina/metabolismo , Adenocarcinoma/patologia , Adenoma/metabolismo , Adenoma/patologia , Adenoma de Células das Ilhotas Pancreáticas , Animais , Anticorpos Neutralizantes/farmacologia , Hipóxia Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Transição Epitelial-Mesenquimal , Humanos , Neoplasias Pulmonares/patologia , Camundongos , Camundongos Transgênicos , Tumores Neuroendócrinos/metabolismo , Tumores Neuroendócrinos/patologia , Fosforilação , Espécies Reativas de Oxigênio/metabolismo , Transdução de Sinais , Proteína Smad2/metabolismo , Tirosina/metabolismo , Fator A de Crescimento do Endotélio Vascular/imunologia , beta Catenina/genética , Quinases da Família src/metabolismo
2.
Clin Transl Oncol ; 13(10): 703-9, 2011 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-21975330

RESUMO

Recent advances in the treatment of prostate cancer have resulted in improved outcomes, including longer survival, but new options are needed for treating patients with castration-resistant disease, particularly in the presence of bone metastasis. Data from preclinical models and clinical biomarker studies indicate that antiangiogenic agents should be a promising treatment for this patient population, and multiple agents in this class have demonstrated activity in early-stage clinical trials. Pivotal trials in prostate cancer with agents targeting vascular endothelial growth factor (VEGF) signalling have resulted in significant improvements in tumour response and progression-free survival. However, overall survival was not significantly improved. Recent preclinical studies suggest that the limited impact on overall survival may result from the development of evasive resistance after inhibition of angiogenesis, possibly through upregulation of MET (hepatocyte growth factor receptor) signalling. MET plays important roles in angiogenesis, tumour cell invasion and bone metastasis, all of which are key factors in castration-resistant prostate cancer. Inhibition of both the MET and VEGF pathways may improve the efficacy of angiogenesis inhibitors in prostate cancer.


Assuntos
Antineoplásicos/uso terapêutico , Neoplasias da Próstata/tratamento farmacológico , Neoplasias da Próstata/metabolismo , Proteínas Proto-Oncogênicas c-met/antagonistas & inibidores , Fator A de Crescimento do Endotélio Vascular/antagonistas & inibidores , Castração , Sinergismo Farmacológico , Humanos , Masculino , Neoplasias da Próstata/cirurgia , Proteínas Proto-Oncogênicas c-met/metabolismo , Fator A de Crescimento do Endotélio Vascular/metabolismo
3.
Clin. transl. oncol. (Print) ; 13(10): 703-709, oct. 2011. tab
Artigo em Inglês | IBECS | ID: ibc-125923

RESUMO

Recent advances in the treatment of prostate cancer have resulted in improved outcomes, including longer survival, but new options are needed for treating patients with castration-resistant disease, particularly in the presence of bone metastasis. Data from preclinical models and clinical biomarker studies indicate that antiangiogenic agents should be a promising treatment for this patient population, and multiple agents in this class have demonstrated activity in early-stage clinical trials. Pivotal trials in prostate cancer with agents targeting vascular endothelial growth factor (VEGF) signalling have resulted in significant improvements in tumour response and progression-free survival. However, overall survival was not significantly improved. Recent preclinical studies suggest that the limited impact on overall survival may result from the development of evasive resistance after inhibition of angiogenesis, possibly through upregulation of MET (hepatocyte growth factor receptor) signalling. MET plays important roles in angiogenesis, tumour cell invasion and bone metastasis, all of which are key factors in castration-resistant prostate cancer. Inhibition of both the MET and VEGF pathways may improve the efficacy of angiogenesis inhibitors in prostate cancer (AU)


Assuntos
Humanos , Masculino , Antineoplásicos/uso terapêutico , Neoplasias da Próstata/tratamento farmacológico , Neoplasias da Próstata/metabolismo , Proteínas Proto-Oncogênicas c-met/antagonistas & inibidores , Fator A de Crescimento do Endotélio Vascular/antagonistas & inibidores , Castração/métodos , Castração , Sinergismo Farmacológico , Neoplasias da Próstata/cirurgia , Proteínas Proto-Oncogênicas c-met/metabolismo , Fator A de Crescimento do Endotélio Vascular/metabolismo
4.
Diabetologia ; 51(9): 1723-30, 2008 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-18587559

RESUMO

AIMS/HYPOTHESIS: Recent studies suggest that oxidative stress should be monitored alongside HbA(1c) to identify subgroups of diabetic patients at high risk of initiation or progression of retinopathy. The acrolein-derived advanced lipoxidation end-product (ALE), [Formula: see text]-(3-formyl-3,4-dehydropiperidino)lysine (FDP-lysine), is a useful biomarker that reflects the cumulative burden of oxidative stress over long periods of time. The purpose of the present study was to investigate whether serum and haemoglobin levels of FDP-lysine are associated with the severity of diabetic retinopathy in type 1 and type 2 diabetic patients. METHODS: Serum and haemoglobin levels of FDP-lysine were measured by competitive ELISA in 59 type 1 and 76 type 2 diabetic patients with no retinopathy, non-proliferative retinopathy or proliferative retinopathy (mean age [+/-SEM] 54.3 +/- 1.3 years), and in 47 non-diabetic control individuals (mean age 51.9 +/- 2.1 years). RESULTS: Serum and haemoglobin levels of FDP-lysine were significantly increased in diabetic patients compared with control individuals (p = 0.04 and p = 0.002, respectively). However, no significant association was found between levels of serum FDP-lysine and the severity of diabetic retinopathy (p = 0.97). In contrast, increased haemoglobin FDP-lysine levels were observed in patients with proliferative retinopathy compared with patients without retinopathy and with non-proliferative retinopathy (p = 0.04). The relationship of FDP-lysine with proliferative retinopathy was unaltered after adjustment for HbA(1c), or other clinical parameters. CONCLUSIONS/INTERPRETATION: Our data suggest that haemoglobin FDP-lysine may provide a useful risk marker for the development of proliferative diabetic retinopathy independently of HbA(1c), and that elevated intracellular ALE formation may be involved in the pathogenesis of this sight-threatening complication of diabetes.


Assuntos
Retinopatia Diabética/fisiopatologia , Lisina/análogos & derivados , Anticorpos Monoclonais , Biomarcadores , Diabetes Mellitus Tipo 2/sangue , Diabetes Mellitus Tipo 2/complicações , Diabetes Mellitus Tipo 2/fisiopatologia , Retinopatia Diabética/sangue , Retinopatia Diabética/classificação , Ensaio de Imunoadsorção Enzimática , Humanos , Hiperglicemia/complicações , Lisina/sangue , Valores de Referência , Índice de Gravidade de Doença , População Branca
5.
Br J Cancer ; 96(12): 1788-95, 2007 Jun 18.
Artigo em Inglês | MEDLINE | ID: mdl-17519900

RESUMO

Advances in understanding the role of vascular endothelial growth factor (VEGF) in normal physiology are giving insight into the basis of adverse effects attributed to the use of VEGF inhibitors in clinical oncology. These effects are typically downstream consequences of suppression of cellular signalling pathways important in the regulation and maintenance of the microvasculature. Downregulation of these pathways in normal organs can lead to vascular disturbances and even regression of blood vessels, which could be intensified by concurrent pathological conditions. These changes are generally manageable and pose less risk than the tumours being treated, but they highlight the properties shared by tumour vessels and the vasculature of normal organs.


Assuntos
Neoplasias/tratamento farmacológico , Fator A de Crescimento do Endotélio Vascular/antagonistas & inibidores , Inibidores da Angiogênese/efeitos adversos , Anticorpos Monoclonais/efeitos adversos , Anticorpos Monoclonais Humanizados , Antineoplásicos/efeitos adversos , Benzenossulfonatos/efeitos adversos , Bevacizumab , Hemorragia/induzido quimicamente , Humanos , Indóis/efeitos adversos , Neoplasias/patologia , Niacinamida/análogos & derivados , Compostos de Fenilureia , Piridinas/efeitos adversos , Pirróis/efeitos adversos , Transdução de Sinais/efeitos dos fármacos , Sorafenibe , Sunitinibe , Trombose/induzido quimicamente , Fator A de Crescimento do Endotélio Vascular/fisiologia , Cicatrização/efeitos dos fármacos
6.
Am J Respir Crit Care Med ; 164(10 Pt 2): S39-45, 2001 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-11734465

RESUMO

Angiogenesis and microvascular remodeling are known features of chronic inflammatory diseases such as asthma and chronic bronchitis, but the mechanisms and consequences of the changes are just beginning to be elucidated. In a model of chronic airway inflammation produced by Mycoplasma pulmonis infection of the airways of mice or rats, angiogenesis and microvascular remodeling create vessels that mediate leukocyte influx and leak plasma proteins into the airway mucosa. These vascular changes are driven by the immune response to the organisms. Plasma leakage results from gaps between endothelial cells, as well as from increased vascular surface area and probably other changes in the newly formed and remodeled blood vessels. Treatment with long-acting beta2 agonists can reduce but not eliminate the plasma occurring after infection. In addition to the elevated baseline leakage, the remodeled vessels in the airway mucosa are abnormally sensitive to substance P, but not to platelet-activating factor or serotonin, suggesting that the infection leads to a selective upregulation of NK1 receptors on the vasculature. The formation of new vessels and the remodeling of existing vessels are likely to be induced by multiple growth factors, including vascular endothelial growth factor (VEGF) and angiopoietin 1 (Ang1). VEGF increases vascular permeability, but Ang1 has the opposite effect. This feature is consistent with evidence that VEGF and Ang1 play complementary and coordinated roles in vascular growth and remodeling and have powerful effects on vascular function. Regulation of vascular permeability by VEGF and Ang1 may be their most rapid and potent actions in the adult, as these effects can occur independent of their effects on angiogenesis and vascular remodeling. The ability of Ang1 to block plasma leakage without producing angiogenesis may be therapeutically advantageous. Furthermore, because VEGF and Ang1 have additive effects in promoting angiogenesis but opposite effects on vascular permeability, they could be used together to avoid the formation of leaky vessels in therapeutic angiogenesis. Finally, the elucidation of the protective effect of Ang1 on blood vessel leakiness to plasma proteins raises the possibility of a new strategy for reducing airway edema in inflammatory airway diseases such as asthma and chronic bronchitis.


Assuntos
Albuterol/análogos & derivados , Asma/patologia , Asma/fisiopatologia , Bronquite/patologia , Bronquite/fisiopatologia , Pulmão/irrigação sanguínea , Microcirculação , Neovascularização Patológica , Antagonistas Adrenérgicos beta/uso terapêutico , Adulto , Albuterol/administração & dosagem , Albuterol/uso terapêutico , Angiopoietina-1 , Animais , Asma/tratamento farmacológico , Bronquite/tratamento farmacológico , Broncodilatadores/administração & dosagem , Broncodilatadores/uso terapêutico , Permeabilidade Capilar , Doença Crônica , Modelos Animais de Doenças , Fatores de Crescimento Endotelial/fisiologia , Fatores de Crescimento Endotelial/uso terapêutico , Endotélio/citologia , Endotélio/patologia , Humanos , Inflamação/patologia , Inflamação/fisiopatologia , Linfocinas/fisiologia , Glicoproteínas de Membrana/fisiologia , Glicoproteínas de Membrana/uso terapêutico , Camundongos , Camundongos Endogâmicos C57BL , Nebulizadores e Vaporizadores , Pneumonia por Mycoplasma/complicações , Propanolaminas/uso terapêutico , Ratos , Ratos Wistar , Pesquisa , Mucosa Respiratória/irrigação sanguínea , Xinafoato de Salmeterol , Fator A de Crescimento do Endotélio Vascular , Fatores de Crescimento do Endotélio Vascular
7.
Genes Dev ; 15(19): 2520-32, 2001 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-11581158

RESUMO

Hypoxia-inducible factor-1alpha (HIF-1alpha) transactivates genes required for energy metabolism and tissue perfusion and is necessary for embryonic development and tumor explant growth. HIF-1alpha is overexpressed during carcinogenesis, myocardial infarction, and wound healing; however, the biological consequences of HIF-1alpha overexpression are unknown. Here, transgenic mice expressing constitutively active HIF-1alpha in epidermis displayed a 66% increase in dermal capillaries, a 13-fold elevation of total vascular endothelial growth factor (VEGF) expression, and a six- to ninefold induction of each VEGF isoform. Despite marked induction of hypervascularity, HIF-1alpha did not induce edema, inflammation, or vascular leakage, phenotypes developing in transgenic mice overexpressing VEGF cDNA in skin. Remarkably, blood vessel leakage resistance induced by HIF-1alpha overexpression was not caused by up-regulation of angiopoietin-1 or angiopoietin-2. Hypervascularity induced by HIF-1alpha could improve therapy of tissue ischemia.


Assuntos
Vasos Sanguíneos/crescimento & desenvolvimento , Angiopoietina-1 , Angiopoietina-2 , Animais , Sequência de Bases , Primers do DNA , DNA Complementar , Fatores de Crescimento Endotelial/genética , Fatores de Crescimento Endotelial/metabolismo , Humanos , Imuno-Histoquímica , Hibridização In Situ , Linfocinas/genética , Linfocinas/metabolismo , Glicoproteínas de Membrana/genética , Camundongos , Camundongos Transgênicos , Permeabilidade , Proteínas/genética , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Ricina/metabolismo , Pele/irrigação sanguínea , Fator A de Crescimento do Endotélio Vascular , Fatores de Crescimento do Endotélio Vascular
8.
Eur J Immunol ; 31(10): 2910-8, 2001 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-11592066

RESUMO

The mechanisms associated with the immunostimulatory activity of vaccine adjuvants are still poorly understood. We have undertaken a study to determine whether antigen-presenting cell trafficking is modified by administration of the submicron emulsion adjuvant MF59. We investigated the fate of inflammatory macrophages after intramuscular injection of the antigen herpes simplex virus gD2 with fluorescence-labeled MF59. A homogeneous population of macrophages infiltrated the muscle, internalized adjuvant and expressed markers characteristic of mature macrophages over a 48-h period. Macrophage influx to the injection site was reduced by 70% in mice deficient for the chemokine receptor 2 (CCR2). Two distinct cell populations were shown to contain fluorescence-labeled MF59 in the draining lymph node at 48 h post injection. The first population had a round morphology, exhibited bright fluorescence, was located in the subcapsular sinus, and was apoptotic. The second population had a dendritic morphology, was weakly fluorescent, and was located in the T cell area where adjuvant-containing apoptotic bodies identified by TUNEL labeling were present. We propose that lymph node-resident dendritic cells can acquire antigen and MF59 after intramuscular immunization by uptake of the apoptotic macrophages.


Assuntos
Adjuvantes Imunológicos/farmacologia , Apoptose , Macrófagos/fisiologia , Polissorbatos/farmacologia , Esqualeno/farmacologia , Proteínas do Envelope Viral/imunologia , Animais , Movimento Celular , Células Dendríticas/fisiologia , Feminino , Imunização , Linfonodos/patologia , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL
10.
Am J Pathol ; 158(6): 2043-55, 2001 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-11395382

RESUMO

Angiogenesis and vascular remodeling are features of many chronic inflammatory diseases. When diseases evolve slowly, the accompanying changes in the microvasculature would seem to be similarly gradual. Here we report that the rate of endothelial cell proliferation and the size of blood vessels increases rapidly after the onset of an infection that leads to chronic inflammatory airway disease. In C3H mice inoculated with Mycoplasma pulmonis, the tracheal microvasculature, made visible by perfusion of Lycopersicon esculentum lectin, rapidly enlarged from 4 to 7 days after infection and then plateaued. Diameters of arterioles, capillaries, and venules increased on average 148, 214, and 74%, respectively. Endothelial cell proliferation, measured by bromodeoxyuridine (BrdU) labeling, peaked at 5 days (18 times the pathogen-free value), declined sharply until day 9, but remained at approximately 3 times the pathogen-free value for at least 28 days. Remodeled capillaries and venules were sites of focal plasma leakage and extensive leukocyte adherence. Most systemic manifestations of the infection occurred well after the peak of endothelial proliferation, and the humoral immune response to M. pulmonis was among the latest, increasing after 14 days. These data show that endothelial cell proliferation and microvascular remodeling occur at an early stage of chronic airway disease and suggest that the vascular changes precede widespread tissue remodeling.


Assuntos
Endotélio Vascular/patologia , Inflamação/patologia , Microcirculação/patologia , Infecções por Mycoplasma/patologia , Neovascularização Patológica/patologia , Infecções Respiratórias/patologia , Animais , Peso Corporal , Permeabilidade Capilar , Adesão Celular , Divisão Celular , Doença Crônica , DNA/biossíntese , Inflamação/imunologia , Inflamação/microbiologia , Cinética , Leucócitos/imunologia , Pulmão/irrigação sanguínea , Masculino , Camundongos , Camundongos Endogâmicos C3H , Infecções por Mycoplasma/imunologia , Neovascularização Patológica/imunologia , Neovascularização Patológica/microbiologia , Fenótipo , Infecções Respiratórias/imunologia
11.
EMBO J ; 20(6): 1223-31, 2001 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-11250889

RESUMO

Vascular endothelial growth factor receptor-3 (VEGFR-3) has an essential role in the development of embryonic blood vessels; however, after midgestation its expression becomes restricted mainly to the developing lymphatic vessels. The VEGFR-3 ligand VEGF-C stimulates lymphangiogenesis in transgenic mice and in chick chorioallantoic membrane. As VEGF-C also binds VEGFR-2, which is expressed in lymphatic endothelia, it is not clear which receptors are responsible for the lymphangiogenic effects of VEGF-C. VEGF-D, which binds to the same receptors, has been reported to induce angiogenesis, but its lymphangiogenic potential is not known. In order to define the lymphangiogenic signalling pathway we have created transgenic mice overexpressing a VEGFR-3-specific mutant of VEGF-C (VEGF-C156S) or VEGF-D in epidermal keratinocytes under the keratin 14 promoter. Both transgenes induced the growth of lymphatic vessels in the skin, whereas the blood vessel architecture was not affected. Evidence was also obtained that these growth factors act in a paracrine manner in vivo. These results demonstrate that stimulation of the VEGFR-3 signal transduction pathway is sufficient to induce specifically lymphangiogenesis in vivo.


Assuntos
Fatores de Crescimento Endotelial/metabolismo , Sistema Linfático/metabolismo , Linfocinas/metabolismo , Receptores Proteína Tirosina Quinases/metabolismo , Receptores de Fatores de Crescimento/metabolismo , Pele/metabolismo , Animais , Meia-Vida , Hiperplasia , Sistema Linfático/crescimento & desenvolvimento , Sistema Linfático/patologia , Camundongos , Camundongos Transgênicos , Comunicação Parácrina , Receptores Proteína Tirosina Quinases/genética , Receptores de Fatores de Crescimento/genética , Proteínas Recombinantes/metabolismo , Transdução de Sinais , Pele/irrigação sanguínea , Pele/crescimento & desenvolvimento , Pele/patologia , Fator A de Crescimento do Endotélio Vascular , Fator C de Crescimento do Endotélio Vascular , Fator D de Crescimento do Endotélio Vascular , Receptor 3 de Fatores de Crescimento do Endotélio Vascular , Fatores de Crescimento do Endotélio Vascular
12.
Dev Biol ; 230(2): 151-60, 2001 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-11161569

RESUMO

The Eph receptor tyrosine kinases and their membrane-tethered ephrin ligands provide critical guidance cues at points of cell-to-cell contact. It has recently been reported that the ephrin-B2 ligand is a molecular marker for the arterial endothelium at the earliest stages of embryonic angiogenesis, while its receptor EphB4 reciprocally marks the venous endothelium. These findings suggested that ephrin-B2 and EphB4 are involved in establishing arterial versus venous identity and perhaps in anastamosing arterial and venous vessels at their junctions. By using a genetically engineered mouse in which the lacZ coding region substitutes and reports for the ephrin-B2 coding region, we demonstrate that ephrin-B2 expression continues to selectively mark arteries during later embryonic development as well as in the adult. However, as development proceeds, we find that ephrin-B2 expression progressively extends from the arterial endothelium to surrounding smooth muscle cells and to pericytes, suggesting that ephrin-B2 may play an important role during formation of the arterial muscle wall. Furthermore, although ephrin-B2 expression patterns vary in different vascular beds, it can extend into capillaries about midway between terminal arterioles and postcapillary venules, challenging the classical conception that capillaries have neither arterial nor venous identity. In adult settings of angiogenesis, as in tumors or in the female reproductive system, the endothelium of a subset of new vessels strongly expresses ephrin-B2, once again contrary to earlier views that such new vessels lack arterial/venous characteristics and derive from postcapillary venules. While earlier studies had focused on a role for ephrin-B2 during the earliest embryonic stages of arterial/venous determination, our current findings using ephrin-B2 as an arterial marker in the adult challenge prevailing views of the arterial/venous identity of quiescent as well as remodeling adult microvessels and also highlight a possible role for ephrin-B2 in the formation of the arterial muscle wall.


Assuntos
Artérias/metabolismo , Endotélio Vascular/metabolismo , Neoplasias Pulmonares/irrigação sanguínea , Proteínas de Membrana/genética , Músculo Liso Vascular/metabolismo , Neovascularização Patológica/metabolismo , Animais , Arteríolas/metabolismo , Biomarcadores , Capilares/metabolismo , Endotélio Vascular/patologia , Efrina-B2 , Regulação da Expressão Gênica , Proteínas de Membrana/análise , Camundongos , Camundongos Transgênicos , Músculo Liso Vascular/patologia , Neovascularização Patológica/patologia , Especificidade de Órgãos , Vênulas/metabolismo , beta-Galactosidase/genética
13.
Am J Physiol Lung Cell Mol Physiol ; 280(2): L286-97, 2001 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-11159008

RESUMO

Angiogenesis and microvascular remodeling are features of chronic airway inflammation caused by Mycoplasma pulmonis infection in rats. As airway blood vessels undergo remodeling, they become unusually sensitive to substance P-induced plasma leakage. Here we determined whether the remodeled vessels are leaky under baseline conditions, whether their heightened sensitivity is specific to substance P, and whether the leakage is reversible. Four weeks after infection, the amount of baseline leakage of Evans blue in the tracheal mucosa was two to five times the normal level. Gaps < 1 microm in diameter were located between endothelial cells in some remodeled vessels. Substance P, but not platelet-activating factor or 5-hydroxytryptamine, produced an exaggerated leakage response. Inhalation of the beta2-adrenergic receptor agonist salmeterol reduced the leakage by <60%. We conclude that the blood vessel remodeling after M. pulmonis infection is associated with microvascular leakiness due, in part, to the formation of endothelial gaps. This leakage is accompanied by an abnormal sensitivity to substance P but not to platelet-activating factor or 5-hydroxytryptamine and can be reduced by beta2-agonists.


Assuntos
Albuterol/análogos & derivados , Permeabilidade Capilar , Hipersensibilidade a Drogas/metabolismo , Infecções por Mycoplasma/metabolismo , Substância P/metabolismo , Traqueia/metabolismo , Albuterol/farmacologia , Animais , Broncodilatadores/farmacologia , Permeabilidade Capilar/efeitos dos fármacos , Doença Crônica , Relação Dose-Resposta a Droga , Hipersensibilidade a Drogas/patologia , Azul Evans , Extravasamento de Materiais Terapêuticos e Diagnósticos/metabolismo , Extravasamento de Materiais Terapêuticos e Diagnósticos/patologia , Indóis , Masculino , Infecções por Mycoplasma/patologia , Tamanho do Órgão , Compostos Organometálicos , Fator de Ativação de Plaquetas/farmacologia , Ratos , Ratos Endogâmicos F344 , Ratos Wistar , Xinafoato de Salmeterol , Serotonina/farmacologia , Especificidade da Espécie , Organismos Livres de Patógenos Específicos , Substância P/farmacologia , Traqueia/irrigação sanguínea , Traqueia/efeitos dos fármacos , Traqueia/patologia
14.
Proc Natl Acad Sci U S A ; 97(26): 14608-13, 2000 Dec 19.
Artigo em Inglês | MEDLINE | ID: mdl-11121063

RESUMO

The presence of "mosaic" vessels in which both endothelial cells and tumor cells form the luminal surface has profound implications for metastasis, drug delivery, and antivascular therapy. Yet little is known of the frequency, and thus importance, of mosaic vessels in tumors. Using CD31 and CD105 to identify endothelial cells and endogenous green fluorescent protein labeling of tumor cells, we show that approximately 15% of perfused vessels of a colon carcinoma xenografted at two different sites in mice were mosaic vessels having focal regions where no CD31/CD105 immunoreactivity was detected and tumor cells appeared to contact the vessel lumen. These regions occupied approximately 25% of the perimeter of the mosaic vessels, or approximately 4% of the total vascular surface area in these colon carcinomas. In addition, we found similar numbers of mosaic vessels in human colon carcinoma biopsies. Our results are consistent with the observation that approximately 10(6) cells are shed daily per g of tumor. More importantly, our data offer a possible explanation for the antivascular effects of cytotoxic agents and suggest potential strategies for targeting the tumor vasculature.


Assuntos
Neoplasias do Colo/sangue , Neovascularização Patológica , Animais , Antígenos CD , Neoplasias do Colo/patologia , Endoglina , Humanos , Camundongos , Camundongos SCID , Molécula-1 de Adesão Celular Endotelial a Plaquetas/análise , Receptores de Superfície Celular , Células Tumorais Cultivadas , Molécula 1 de Adesão de Célula Vascular/análise
15.
Clin Exp Pharmacol Physiol ; 27(10): 836-41, 2000 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-11022979

RESUMO

1. Chronic inflammation is associated with blood vessel remodelling, including vessel proliferation and enlargement, and changes in vessel phenotype. We sought to characterize these changes in chronic airway inflammation and to determine whether corticosteroids that inhibit inflammation, such as dexamethasone, can also reduce microvascular remodelling. 2. Chronic airway inflammation was induced in C3H mice by infection with Mycoplasmapulmonis and the tracheal vessels treatment also decreased the immunoreactivity for P-selectin and the number of adherent leucocytes (595 +/- 203 vs 2,024 +/- 393 cells/ mm2 in treated and non-treated infected mice, respectively). 6. We conclude that microvascular enlargement and changes in vessel phenotype are features of some types of chronic inflammation and, furthermore, that dexamethasone reverses the microvascular enlargement, changes in vessel phenotype and leucocyte influx associated with chronic inflammatory airway disease.


Assuntos
Endotélio Vascular/patologia , Neovascularização Patológica/fisiopatologia , Pneumonia Bacteriana/fisiopatologia , Traqueia/irrigação sanguínea , Animais , Permeabilidade Capilar , Doença Crônica , Dexametasona/uso terapêutico , Endotélio Vascular/metabolismo , Glucocorticoides/uso terapêutico , Leucócitos/efeitos dos fármacos , Leucócitos/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C3H , Mycoplasma/crescimento & desenvolvimento , Neovascularização Patológica/tratamento farmacológico , Neovascularização Patológica/metabolismo , Selectina-P/metabolismo , Pneumonia Bacteriana/tratamento farmacológico , Pneumonia Bacteriana/metabolismo , Traqueia/metabolismo , Traqueia/patologia
16.
J Immunol ; 165(5): 2850-8, 2000 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-10946318

RESUMO

Intramuscular injection of DNA vaccines elicits potent humoral and cellular immune responses in mice. However, DNA vaccines are less efficient in larger animal models and humans. To gain a better understanding of the factors limiting the efficacy of DNA vaccines, we used fluorescence-labeled plasmid DNA in mice to 1) define the macroscopic and microscopic distribution of DNA after injection into the tibialis anterior muscle, 2) characterize cellular uptake and expression of DNA in muscle and draining lymph nodes, and 3) determine the effect of modifying DNA distribution and cellular uptake by volume changes or electroporation on the magnitude of the immune response. Injection of a standard 50-microl dose resulted in the rapid dispersion of labeled DNA throughout the muscle. DNA was internalized within 5 min by muscle cells near the injection site and over several hours by cells that were located along muscle fibers and in the draining lymph nodes. Histochemical staining and analysis of mRNA expression in isolated cells by RT-PCR showed that the transgene was detectably expressed only by muscle cells, despite substantial DNA uptake by non-muscle cells. Reduction of the injection volume to 5 microl resulted in substantially less uptake and expression of DNA by muscle cells, and correspondingly lower immune responses against the transgene product. However, expression and immunogenicity were restored when the 5-microl injection was followed by electroporation in vivo. These findings indicate that distribution and cellular uptake significantly affect the immunogenicity of DNA vaccines.


Assuntos
Vacinas de DNA/imunologia , Vacinas de DNA/farmacocinética , Vacinas contra a AIDS/administração & dosagem , Vacinas contra a AIDS/genética , Vacinas contra a AIDS/imunologia , Vacinas contra a AIDS/farmacocinética , Animais , Antígenos Virais/administração & dosagem , Antígenos Virais/imunologia , DNA Viral/metabolismo , Eletroporação , Regulação da Expressão Gênica , Produtos do Gene gag/biossíntese , Produtos do Gene gag/genética , Produtos do Gene gag/imunologia , Anticorpos Anti-HIV/biossíntese , Anticorpos Anti-HIV/sangue , Injeções Intramusculares , Luciferases/genética , Luciferases/metabolismo , Linfonodos/citologia , Linfonodos/metabolismo , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Transgênicos , Músculo Esquelético/citologia , Músculo Esquelético/enzimologia , Músculo Esquelético/metabolismo , Plasmídeos/administração & dosagem , Plasmídeos/imunologia , Transgenes/imunologia , Vacinas de DNA/administração & dosagem , Vacinas de DNA/genética
17.
Am J Pathol ; 156(4): 1363-80, 2000 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-10751361

RESUMO

Leakiness of blood vessels in tumors may contribute to disease progression and is key to certain forms of cancer therapy, but the structural basis of the leakiness is unclear. We sought to determine whether endothelial gaps or transcellular holes, similar to those found in leaky vessels in inflammation, could explain the leakiness of tumor vessels. Blood vessels in MCa-IV mouse mammary carcinomas, which are known to be unusually leaky (functional pore size 1.2-2 microm), were compared to vessels in three less leaky tumors and normal mammary glands. Vessels were identified by their binding of intravascularly injected fluorescent cationic liposomes and Lycopersicon esculentum lectin and by CD31 (PECAM) immunoreactivity. The luminal surface of vessels in all four tumors had a defective endothelial monolayer as revealed by scanning electron microscopy. In MCa-IV tumors, 14% of the vessel surface was lined by poorly connected, overlapping cells. The most superficial lining cells, like endothelial cells, had CD31 immunoreactivity and fenestrae with diaphragms, but they had a branched phenotype with cytoplasmic projections as long as 50 microm. Some branched cells were separated by intercellular openings (mean diameter 1.7 microm; range, 0.3-4.7 microm). Transcellular holes (mean diameter 0.6 microm) were also present but were only 8% as numerous as intercellular openings. Some CD31-positive cells protruded into the vessel lumen; others sprouted into perivascular tumor tissue. Tumors in RIP-Tag2 mice had, in addition, tumor cell-lined lakes of extravasated erythrocytes. We conclude that some tumor vessels have a defective cellular lining composed of disorganized, loosely connected, branched, overlapping or sprouting endothelial cells. Openings between these cells contribute to tumor vessel leakiness and may permit access of macromolecular therapeutic agents to tumor cells.


Assuntos
Permeabilidade Capilar , Endotélio Vascular/patologia , Espaço Extracelular/fisiologia , Neoplasias Mamárias Animais/irrigação sanguínea , Neoplasias Mamárias Animais/metabolismo , Animais , Vasos Sanguíneos/metabolismo , Vasos Sanguíneos/patologia , Feminino , Masculino , Neoplasias Mamárias Animais/patologia , Neoplasias Mamárias Animais/fisiopatologia , Camundongos , Microscopia Eletrônica , Microscopia Eletrônica de Varredura , Microscopia de Fluorescência , Transplante de Neoplasias
18.
Microcirculation ; 7(1): 67-80, 2000 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-10708338

RESUMO

Inflammatory stimuli cause plasma leakage and leukocyte adhesion in venules but not in capillaries or arterioles. The specific response of venules is governed by phenotypic specialization of the venular endothelial cells. What regulates this specialized phenotype? Several recent developments have shed new light on this question and may challenge our thinking about regulation of the venular endothelial cell phenotype. In this review, we consider some of the molecular markers of venular endothelial cells, the hemodynamic and molecular factors that may regulate the phenotype of venular endothelial cells, and abnormalities in endothelial cell phenotype in disease-related angiogenesis and microvascular remodeling. The expanding list of molecular markers may help clarify the physiologic and molecular factors that regulate the phenotype of venular endothelial cells in normal development and disease.


Assuntos
Endotélio Vascular/citologia , Vênulas/citologia , Angiopoietina-1 , Animais , Biomarcadores , Velocidade do Fluxo Sanguíneo , Pressão Sanguínea , Síndrome de Vazamento Capilar/fisiopatologia , Permeabilidade Capilar , Adesão Celular , Citocinas/fisiologia , Glicoconjugados/fisiologia , Humanos , Inflamação/fisiopatologia , Leucócitos/fisiologia , Masculino , Glicoproteínas de Membrana/fisiologia , Camundongos , Camundongos Transgênicos , Neovascularização Patológica/patologia , Neovascularização Fisiológica , Especificidade de Órgãos , Fenótipo , Ratos , Receptores Proteína Tirosina Quinases/fisiologia , Receptor EphB4 , Receptor TIE-2 , Receptores de Superfície Celular/efeitos dos fármacos , Receptores de Superfície Celular/fisiologia , Receptores da Família Eph , Transdução de Sinais , Fator de Crescimento Transformador beta/fisiologia
19.
Nat Med ; 6(4): 460-3, 2000 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-10742156

RESUMO

Pathological increases in vascular leakage lead to edema and swelling, causing serious problems in brain tumors, in diabetic retinopathy, after strokes, during sepsis and also in inflammatory conditions such as rheumatoid arthritis and asthma. Although many agents and disease processes increase vascular leakage, no known agent specifically makes vessels resistant to leaking. Vascular endothelial growth factor (VEGF) and the angiopoietins function together during vascular development, with VEGF acting early during vessel formation, and angiopoietin-1 acting later during vessel remodeling, maturation and stabilization. Although VEGF was initially called vascular permeability factor, there has been less focus on its permeability actions and more effort devoted to its involvement in vessel growth and applications in ischemia and cancer. Recent transgenic approaches have confirmed the profound permeability effects of VEGF (refs. 12-14), and have shown that transgenic angiopoietin-1 acts reciprocally as an anti-permeability factor when provided chronically during vessel formation, although it also profoundly affects vascular morphology when thus delivered. To be useful clinically, angiopoietin-1 would have to inhibit leakage when acutely administered to adult vessels, and this action would have to be uncoupled from its profound angiogenic capabilities. Here we show that acute administration of angiopoietin-1 does indeed protect adult vasculature from leaking, countering the potentially lethal actions of VEGF and inflammatory agents.


Assuntos
Glicoproteínas de Membrana/farmacologia , Pele/irrigação sanguínea , Doenças Vasculares/tratamento farmacológico , Angiopoietina-1 , Animais , Permeabilidade Capilar/efeitos dos fármacos , Linhagem Celular Transformada , Fatores de Crescimento Endotelial/genética , Fatores de Crescimento Endotelial/farmacologia , Vetores Genéticos , Células HeLa , Humanos , Linfocinas/genética , Linfocinas/farmacologia , Glicoproteínas de Membrana/genética , Camundongos , Camundongos Nus , Camundongos Transgênicos , Proteínas Recombinantes/farmacologia , Pele/patologia , Células Tumorais Cultivadas , Fator A de Crescimento do Endotélio Vascular , Fatores de Crescimento do Endotélio Vascular
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