ORIGINAL ARTICLE TNF-a and the IFN-c-inducible protein 10 (IP-10/CXCL-10) delivered by parvoviral vectors act in synergy to induce antitumor effects in mouse glioblastoma M Enderlin 1,2 , EV Kleinmann 1,2 , S Struyf 3 , C Buracchi 4 , A Vecchi 4 , R Kinscherf 5 , F Kiessling 6 , S Paschek 1,2 , S Sozzani 7 , J Rommelaere 1,2 , JJ Cornelis 1,2 , J Van Damme 3 and C Dinsart 1,2 1 Deutsches Krebsforschungszentrum, Infection and Cancer Program, Heidelberg, Germany; 2 Institut National delaSante ´etdelaRechercheMe´dicaleU701,Heidelberg,Germany; 3 Laboratory of Molecular Immunology, Rega Institute, University of Leuven, Belgium; 4 Istituto Clinico Humanitas and Fondazione Humanitas per la Ricerce, Rozzano, Italy; 5 Department of Anatomy and Cell Biology, University of Heidelberg, Heidelberg, Germany; 6 Imaging and Radiooncology Program, Junior Group Molecular Imaging, Deutsches Krebsforschungszentrum, Heidelberg, Germany and 7 Section of General Pathology and Immunology, University of Brescia, Brescia, Italy Interferon-g-inducible protein 10 is a potent chemoattractant for natural killer cells and activated T lymphocytes. It also displays angiostatic properties and some antitumor activity. Tumor necrosis factor-a (TNF-a) is a powerful immunomodulating cytokine with demonstrated tumoricidal activity in various tumor models and the ability to induce strong immune responses. This prompted us to evaluate the antitumor effects of recombinant parvoviruses designed to deliver IP-10 or TNF-a into a glioblastoma. When Gl261 murine glioma cells were infected in vitro with an IP-10- or TNF-a-transducing parvoviral vector and were subcutaneously implanted in mice, tumor growth was significantly delayed. Complete tumor regression was observed when the glioma cells were coinfected with both the vectors, demonstrating synergistic antitumor activity. In an established in vivo glioma model, however, repeated simultaneous peritumoral injection of the IP-10- and TNF-a-delivering parvoviruses failed to improve the therapeutic effect as compared with the use of a single cytokine-delivering vector. In this tumor model, cytokine-mediated immunostimulation, rather than inhibition of vascularization, is likely responsible for the therapeutic efficacy. Cancer Gene Therapy (2009) 16, 149–160; doi:10.1038/cgt.2008.62; published online 1 August 2008 Keywords: IP-10/CXCL10; cytokine; parvoviral vector; glioma Introduction Gliomas are highly malignant brain tumors. The median survival time of patients diagnosed with glioblastoma multiforme is less than 1 year. These tumors are particularly refractory to most conventional anticancer therapies, including surgical resection, radiation therapy and chemotherapy. 1,2 The limited efficacy of current standard treatments makes it necessary to investigate alternative therapeutic approaches, among which those based on immunostimulation seem promising. 3,4 One approach relies on cytokines inducing an increased immune response within the tumor. 5,6 Another involves ex vivo manipulation of effector cells (dendritic cells, DCs); for example, stimulating them with specific antigens or promoting their maturation. 7 A hallmark of glioblastoma is the high degree of neovascularization observed within the tumor. 8–10 Inhibition of angiogenesis might be a powerful strategy for impeding the growth of vascularized tumors. The therapeutic effectiveness of targeting glioma-induced angiogenesis has indeed been demonstrated in various experimental systems. 10–15 Interferon-g (IFN-g)-inducible protein 10 (IP-10/ CXCL10) is a member of the ELR  CXC chemokine family. It is a potent chemoattractant for natural killer and activated T cells, acting through the CXCR3 receptor. 16,17 It also displays angiostatic properties. 18–20 It is synergisti- cally induced in various cell types by IFN-g, other cytokines and Toll-like receptor ligands. 21 Antitumor effects of IP-10, used alone 22 or in synergy with other cytokines, 23 have been demonstrated in vivo by forced expression in tumors and also in adoptive T-cell therapy. 24,25 As both the angiostatic and the immunomodulatory properties of this chemokine Received 23 January 2008; revised 9 May 2008; accepted 23 June 2008; published online 1 August 2008 Correspondence: Dr C Dinsart, Deutsches Krebsforschungszentrum and INSERM U701, Tumor Virology Division, Abteilung F010, Im Neuenheimer Feld 242, Heidelberg D-69120, Germany. E-mail: c.dinsart@dkfz.de Cancer Gene Therapy (2009) 16, 149–160 r 2009 Nature Publishing Group All rights reserved 0929-1903/09 $32.00 www.nature.com/cgt