Carcinogenesis Advance Access first published online on January 23, 2009
This version published online on January 23, 2009
Carcinogenesis, doi:10.1093/carcin/bgp030
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Microparticles harboring Sonic Hedgehog promote angiogenesis through the up-regulation of adhesion proteins and pro-angiogenic factors
1 CNRS, UMR 6214, INSERM, U771, Université d'Angers, Faculté de Médecine, Angers, F-49045 France
2 Department of Human Anatomy and Histology, University of Bari, Bari, Italy
Reprint requests should be sent to M.C. Martínez, Biologie Neuro-Vasculaire Intégrée, CNRS UMR 6214-INSERM U771, Faculté de Médecine, Rue Haute de Reculée, 49045 Angers (France). Phone: + 33 2 41 73 58 57; Fax: +33 2 41 73 58 95. E-mail: carmen.martinez{at}univ-angers.fr
Microparticles are small fragments generated from the plasma membrane after cell stimulation or apoptosis. We have recently shown that microparticles harboring the morphogen Sonic Hedgehog (MPsShh+) correct endothelial injury by release of nitric oxide from endothelial cells (Agouni et al., FASEB J. 11: 2735-2741, 2007). Here, we show that MPsShh+ induce the formation of capillary-like structures in an in vitro model using human endothelial cells, although they inhibited cell migration. Besides, MPsShh+ regulate cell proliferation. Both cell adhesion and expression of proteins involved in this process such as Rho A and phosphorylation of focal activated kinase were increased by MPsShh+, via a ROCK inhibitor-sensitive pathway. We demonstrate that MPsShh+ increase mRNA and protein levels of pro-angiogenic factors as measured by qRT-PCR and Western blot. In spite of VEGF expression, conditioned media from endothelial cells treated avec MPsShh+ reduces angiogenesis. Interestingly, the effects induced by MPsShh+ on the formation of capillary-like structures, expression of adhesion molecules and pro-angiogenic factors were reversed after silencing of the Shh receptor, using siRNA or when Sonic Hedgehog signaling was pharmacologically inhibited with cyclopamine. Taken together, we show that Sonic Hedgehog carried by MPsShh+ regulate angiogenesis probably through both a direct and an indirect mechanisms, and we propose that MPs harboring Sonic Hedgehog may contribute to the generation of a vascular network in pathologies associated with tumor growth.
Key Words: Microvesicles • angiogenesis • morphogens • vascular endothelial growth factor
* These authors participated equally in this work.
This work was supported in part by grants from Fonds Européen pour le Développement Régional (R.A. n° 8891), Agence Nationale pour la Recherche (M.C.M. n°ANR-07-PHYSIO-010-01), CNRS, INSERM et Université d'Angers. R.S. and T.B. are recipients of a doctoral fellowship from Italian and French Education Ministry (MENRT), respectively.
Received August 12, 2008; revised December 20, 2008; accepted January 18, 2009.