RESUMEN
Anti-angiogenesis represents a promising therapeutic strategy for the treatment of various malignancies. Isthmin (ISM) is a gene highly expressed in the isthmus of the midbrain-hindbrain organizer in Xenopus with no known functions. It encodes a secreted 60 kD protein containing a thrombospondin type 1 repeat domain in the central region and an adhesion-associated domain in MUC4 and other proteins (AMOP) domain at the C-terminal. In this work, we demonstrate that ISM is a novel angiogenesis inhibitor. Recombinant mouse ISM inhibited endothelial cell (EC) capillary network formation on Matrigel through its C-terminal AMOP domain. It also suppressed vascular endothelial growth factor (VEGF)-basic fibroblast growth factor (bFGF) induced in vivo angiogenesis in mouse. It mitigated VEGF-stimulated EC proliferation without affecting EC migration. Furthermore, ISM induced EC apoptosis in the presence of VEGF through a caspase-dependent pathway. ISM binds to αvß(5) integrin on EC surface and supports EC adhesion. Overexpression of ISM significantly suppressed mouse B16 melanoma tumour growth through inhibition of tumour angiogenesis without affecting tumour cell proliferation. Knockdown of isthmin in zebrafish embryos using morpholino antisense oligonucleotides led to disorganized intersegmental vessels in the trunk. Our results demonstrate that ISM is a novel endogenous angiogenesis inhibitor with functions likely in physiological as well as pathological angiogenesis.
Asunto(s)
Melanoma Experimental/patología , Neovascularización Patológica , Neovascularización Fisiológica , Proteínas/metabolismo , Proteínas de Pez Cebra/metabolismo , Secuencia de Aminoácidos , Inhibidores de la Angiogénesis/metabolismo , Inhibidores de la Angiogénesis/farmacología , Animales , Apoptosis , Adhesión Celular , Movimiento Celular/efectos de los fármacos , Proliferación Celular , Clonación Molecular , Factor 2 de Crecimiento de Fibroblastos/antagonistas & inhibidores , Humanos , Integrinas/metabolismo , Péptidos y Proteínas de Señalización Intercelular , Melanoma Experimental/irrigación sanguínea , Melanoma Experimental/metabolismo , Ratones , Datos de Secuencia Molecular , Trasplante de Neoplasias , Proteínas/química , Proteínas/genética , Proteínas/farmacología , Proteínas Recombinantes/metabolismo , Alineación de Secuencia , Trasplante Heterólogo , Factor A de Crecimiento Endotelial Vascular/antagonistas & inhibidores , Pez Cebra , Proteínas de Pez Cebra/química , Proteínas de Pez Cebra/genética , Proteínas de Pez Cebra/farmacologíaRESUMEN
Angiogenesis is critical for tumour growth and metastasis where factors that regulate this process are potential targets for development of anti-cancer drugs. In this study, we show that the first TSR domain of the extracellular matrix protease ADAMTS5, unlike the second TSR, has anti-angiogenic activities where it inhibits endothelial cell tube formation on Matrigel, reduces cell proliferation and attachment, while promoting cell apoptosis and migration, all in a dose-dependent manner. Furthermore, it influences the architecture of endothelial cells by disrupting actin stress fibres and reducing focal adhesions, likely via suppressing RhoA activation. TSR1 of ADAMTS5 is therefore a novel anti-angiogenic peptide and could serve as a prototype for future development into anti-cancer drugs.
