Please cite this article in press as: S.J. Soenen, et al., Nano Today (2013), http://dx.doi.org/10.1016/j.nantod.2012.12.001 ARTICLE IN PRESS +Model NANTOD-287; No. of Pages 5 Nano Today (2013) xxx, xxx—xxx Available online at www.sciencedirect.com jo u rn al hom epage : www.elsevier.com/locate/nanotoday NEWS AND OPINIONS Turning a frown upside down: Exploiting nanoparticle toxicity for anticancer therapy Stefaan J. Soenen a,b , Jo Demeester a , Stefaan C. De Smedt a,* , Kevin Braeckmans a,b a Lab of General Biochemistry and Physical Pharmacy, Faculty of Pharmaceutical Sciences, Ghent University, B9000 Ghent, Belgium b Centre for Nano- and Biophotonics, Ghent University, B9000 Ghent, Belgium Received 17 October 2012; received in revised form 5 December 2012; accepted 6 December 2012 KEYWORDS Nanoparticles; Nanotoxicology; Cancer therapy; Autophagy; Particle degradation; Quantum dot; Zinc oxide Abstract The use of nanosized materials is rapidly increasing, both in technological appli- cations for daily use and in biomedical research. The use of these materials, especially for biomedical purposes is however still limited as the potential toxicity of nanomaterials warrants a lot of caution. The generation of a lot of toxicological data concerning nanomaterials some- times creates a negative perception on their use. However, not all nanomaterials are the same and our understanding of how toxicity exerts itself and ways of how to control it for various particles is increasing. This control also offers us the possibility to exploit nanoparticle toxicity in a targeted manner, by means of selective autophagy induction or leaching of metal ions as a novel anticancer therapy. This manuscript provides an overview of work done on these topics, important achievements and key issues that need to be resolved to mature this novel scientific discipline. © 2012 Elsevier Ltd. All rights reserved. The use of nanosized materials in cancer therapy is being extensively studied in trying to optimize multiple factors such as targeting efficacy, controlled drug release or exter- nally triggered hyperthermia [1]. Recently, several groups have explored a novel nanomaterial-based therapy, exploi- ting the intrinsic toxicity of several types of nanomaterials. Various studies have found that many different types of nanomaterials can induce cellular autophagy and/or cell death by ion leaching [2,3]. Interestingly, the extent of * Corresponding author. Tel.: +32 9 264 8067; fax: +32 9 264 8189. E-mail address: Stefaan.DeSmedt@UGent.be (S.C. De Smedt). these effects appears to be highly dependent on the nature of the cells, as cancerous cell types were found to be far more susceptible than non-cancerous cells [4]. Both in vitro and in vivo data have demonstrated the potential of these methodologies. Although the field of nanotoxicology remains under full development, several common mechanisms have been found and in general, there is a reasonable control over the extent of nanomaterial-related toxicity. Therefore, researchers believe that the intrinsic toxicity of nanomaterials could be exploited as a novel anticancer therapy [5]. Currently, two strategies have attracted special interest by multiple research groups: (1) the induction of autophagy by a wide 1748-0132/$ — see front matter © 2012 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.nantod.2012.12.001