In vivo tumor targeting via nanoparticle-mediated therapeutic siRNA coupled to inflammatory response in lung cancer mouse models João Conde a, b, 1 , Furong Tian c, 1 , Yulán Hernández a , Chenchen Bao c, d , Daxiang Cui d , Klaus-Peter Janssen e , M. Ricardo Ibarra a , Pedro V. Baptista b , Tobias Stoeger c, * , Jesús M. de la Fuente a, * a Instituto de Nanociencia de Aragon (INA), Universidad de Zaragoza, Zaragoza 50018, Spain b CIGMH, Departamento de Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Campus de Caparica, 2829-516 Caparica, Portugal c Comprehensive Pneumology Centre, Institute of Lung Biology and Disease, Helmholtz Zentrum München, Neuherberg, Germany d Department of Bio-Nano Science and Engineering, National Key Laboratory of Micro/Nano Fabrication Technology, Institute of Micro&Nano Science and Technology, Shanghai JiaoTong University, P.R.China e Department of Surgery, Klinikum rechts der Isar, Technische Universität München, Ismaninger Strasse 22, Munich, Germany article info Article history: Received 2 May 2013 Accepted 23 June 2013 Available online xxx Keywords: RGD/siRNA nanoparticles Gene silencing Inflammatory response Mice tumor targeting Lung cancer therapy abstract Up to now, functionalized gold nanoparticles have been optimized as an effective intracellular in vitro delivery vehicle for siRNAs to interfere with the expression of specific genes by selective targeting, and provide protection against nucleases. Few examples however of suchlike in vivo applications have been described so far. In this study, we report the use of siRNA/RGD gold nanoparticles capable of targeting tumor cells in a lung cancer syngeneic orthotopic murine model. Therapeutic RGD-nanoparticle treatment resulted in successful targeting evident from significant c-myc oncogene down-regulation followed by tumor growth inhibition and prolonged survival of lung tumor bearing mice, possibly via avb3 integrin inter- action. Our results suggest that RGD gold nanoparticles-mediated delivery of siRNA by intratracheal instillation in mice leads to successful suppression of tumor cell proliferation and respective tumor size reduction. These results reiterate the capability of functionalized gold nanoparticles for targeted delivery of siRNA to cancer cells towards effective silencing of the specific target oncogene. What is more, we demonstrate that the gold-nanoconjugates trigger a complex inflammatory and immune response that might promote the therapeutic effect of the RNAi to reduce tumor size with low doses of siRNA. Ó 2013 Elsevier Ltd. All rights reserved. 1. Introduction RNA interference via the use of small-interfering RNA (siRNA) [1,2] is a powerful and useful tool to block gene function through sequence-specific post-transcriptional gene silencing, playing an important role in the down-regulation of gene expression. siRNAs can be transfected into mammalian cells by a variety of methods [3e5] that influence the strength and duration of the silencing response, which in turn is affected by the amount of siRNA effec- tively delivered and by the potential of each siRNA to suppress its target. Nevertheless, naked siRNAs show extremely short half-lives due to RNases activity, poor chemical stability, and dissociation from the vector [2]. In fact, the major obstacle to clinical application is the uncertainty about how to deliver siRNA with maximal ther- apeutic impact. Nanotechnology in general, and nanoparticles in particular, offer unprecedented opportunities towards effective cancer therapy [6], as multifunctional devices capable of bypassing biological barriers for the specific delivery of therapeutic agents, reducing systemic toxicity and severe adverse side effects avoiding the undesirable distribution to healthy organs and tissues [7,8]. Nowadays the main challenge in therapy is to develop a delivery system capable of circulating in the blood stream undetected by the immune system and capable to recognize a desirable target and signal it for effective drug delivery or gene silencing. Due to their chemical properties and ease of surface modification with a variety of ligands (e.g. * Corresponding authors. E-mail addresses: tobias.stoeger@helmholtz-muenchen.de (T. Stoeger), jmfuente@unizar.es (J.M. de la Fuente). 1 These authors contribute equal to the paper. Contents lists available at SciVerse ScienceDirect Biomaterials journal homepage: www.elsevier.com/locate/biomaterials 0142-9612/$ e see front matter Ó 2013 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.biomaterials.2013.06.041 Biomaterials xxx (2013) 1e10 Please cite this article in press as: Conde J, et al., In vivo tumor targeting via nanoparticle-mediated therapeutic siRNA coupled to inflammatory response in lung cancer mouse models, Biomaterials (2013), http://dx.doi.org/10.1016/j.biomaterials.2013.06.041