As cancer treatment tools, oncolytic viruses (OV) have yet to realize what some see as their ultimate clinical potential. In this study, we have engineered a chimeric vesicular stomatitis virus (VSV) that is devoid of its natural neurotoxicity while retaining potent oncolytic activity. The envelope glycoprotein (G) of VSV was replaced with a variant glycoprotein of the lymphocytic choriomeningitis virus (LCMV-GP), creating a replicating therapeutic, rVSV (GP), that is benign in normal brain but can effectively eliminate brain cancer in multiple preclinical tumor models in vivo. Furthermore, it can be safely administered systemically to mice and displays greater potency against a spectrum of human cancer cell lines than current OV candidates. Remarkably, rVSV(GP) escapes humoral immunity, thus, for the first time, allowing repeated systemic OV application without loss of therapeutic efficacy. Taken together, rVSV(GP) offers a considerably improved OV platform that lacks several of the major drawbacks that have limited the clinical potential of this technology to date. Cancer Res; 74(13); 3567-78. Ó2014 AACR.

Previously, we described an oncolytic vesicular stomatitis virus variant pseudotyped with the nonneurotropic glycoprotein of the lymphocytic choriomeningitis virus, VSV-GP, which was highly effective in glioblastoma. Here, we tested its potency for the treatment of ovarian cancer, a leading cause of death from gynecological malignancies. Effective oncolytic activity of VSV-GP could be demonstrated in ovarian cancer cell lines and xenografts in mice; however, remission was temporary in most mice. Analysis of the innate immune response revealed that ovarian cancer cell lines were able to respond to and produce type I interferon, inducing an antiviral state upon virus infection. This is in stark contrast to published data for other cancer cell lines, which were mostly found to be interferon incompetent. We showed that in vitro this antiviral state could be reverted by combining VSV-GP with the JAK1/2-inhibitor ruxolitinib. In addition, for the first time, we report the in vivo enhancement of oncolytic virus treatment by ruxolitinib, both in subcutaneous as well as in orthotopic xenograft mouse models, without causing significant additional toxicity. In conclusion, VSV-GP has the potential to be a potent and safe oncolytic virus to treat ovarian cancer, especially when combined with an inhibitor of the interferon response.

Among oncolytic viruses, the vesicular stomatitis virus (VSV) is especially potent and a highly promising agent for the treatment of cancer. But, even though effective against multiple tumor entities in preclinical animal models, replication-competent VSV exhibits inherent neurovirulence, which has so far hindered clinical development. To overcome this limitation, replication-defective VSV vectors for cancer gene therapy have been tested and proven to be safe. However, gene delivery was inefficient and only minor antitumor efficacy was observed. Here, we present semireplication-competent vector systems for VSV (srVSV), composed of two trans-complementing, propagation-deficient VSV vectors. The de novo generated deletion mutants of the two VSV polymerase proteins P (phosphoprotein) and L (large catalytic subunit), VSVΔP and VSVΔL respectively, were used mutually or in combination with VSVΔG vectors. These srVSV systems copropagated in vitro and in vivo without recombinatory reversion to replication-competent virus. The srVSV systems were highly lytic for human glioblastoma cell lines, spheroids, and subcutaneous xenografts. Especially the combination of VSVΔG/VSVΔL vectors was as potent as wild-type VSV (VSV-WT) in vitro and induced long-term tumor regression in vivo without any associated adverse effects. In contrast, 90% of VSV-WT-treated animals succumbed to neurological disease shortly after tumor clearance. Most importantly, even when injected into the brain, VSVΔG/VSVΔL did not show any neurotoxicity. In conclusion, srVSV is a promising platform for virotherapeutic approaches and also for VSV-based vector vaccines, combining improved safety with an increased coding capacity for therapeutic transgenes, potentially allowing for multipronged approaches.Electronic supplementary materialThe online version of this article (doi:10.1007/s00109-012-0863-6) contains supplementary material, which is available to authorized users.

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Introduction: Vesicular stomatitis virus (VSV) is a promising oncolytic virus candidate due to its fast mode of action, high titer production, absence of pre-existing anti-VSV immunity and broad tumor tropism. However, potential neurotoxicity of wild-type VSV and a rapid induction of neutralizing antibodies have been a hindrance for further clinical advancement. Our group previously reported that pseudotyping VSV with the LCMV glycoprotein (VSV-GP) results in complete abrogation of neurotoxicity and the absence of neutralizing antibody induction [1]. Here we addressed to what extent the innate immune response to VSV-GP limits its oncolytic efficacy and analyze means to counter these inhibiting factors. Methods: MTT cell viability and TCID50 viral replication assays were used to quantify oncolytic activity in vitro. VSV-GP oncolytic efficiency was also tested in vivo using both xenograft and syngeneic mouse models. Results: VSV-GP exhibited high oncolytic efficiency in vitro, achieving 80-100% killing at 48-72 h post infection in most ovarian, melanoma, and lung cancer cell lines. Further analysis of resistant cell lines showed that these cells were able to mount an interferon (IFN-I) induced antiviral response. VSV-GP efficacy was also tested for ovarian cancer in vivo using s.c xenograft models and in an orthotopic model. Intratumoral injection of VSV-GP into ovarian s.c. xenografts led to tumor remission in all animals. Relapse was observed and relapsing tumors remained sensitive for successive VSV-GP treatment. Significantly prolonged survival was also observed in an ovarian cancer orthotopic model using IVIS in vivo imaging. Oncolytic potency of VSV-GP was enhanced with combination treatment with Jak1/2 inhibitors. Conclusion: These results confirm that LCMV GP-pseudotyped VSV exhibits a highly beneficial toxicity and efficacy profile. However, tumors escaping complete oncolyse via innate immune system activation require coapplication of targeted immune modulators. Reference: [1] - Muik, A. et al. Re-engineering Vesicular Stomatitis Virus to Abrogate Neurotoxicity, Circumvent Humoral Immunity, and Enhance Oncolytic Potency. Cancer Res 74, 3567-3578, (2014). Citation Format: Carles Rodriguez Urbiola, Catherine Dold, Janine Kimpel, Christian Marth, Frederic Santer, Zoran Culig, Alexander Muik, Tanja Knapp, Ira Winkler, Guido Wollmann, Dorothee Von Laer, Patrik Erlmann. Augmenting the therapeutic efficacy of oncolytic LCMV-GP pseudotyped vesicular stomatitis virus via modulation of the innate immune system. [abstract]. In: Proceedings of the CRI-CIMT-EATI-AACR Inaugural International Cancer Immunotherapy Conference: Translating Science into Survival; September 16-19, 2015; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2016;4(1 Suppl):Abstract nr A191.

Oncolytic viruses (OV) that preferentially replicate in and kill tumor cells are promissing novel treatment option for advanced cancers. Through cell lysis, OV set tumor antigens free, which in combination with the OV adjuvant effect, unleashes a strong anti-tumor immune response. Here, we propose the use of the oncolytic VSV-GP for the treatment of ovarian cancer. Effective oncolytic activity of VSV-GP could be demonstrated in a panel of ovarian cancer cell lines. Analysis of the innate immune response of ovarian cancer cells to VSV-GP revealed IFN type I production and induction of an antiviral state of the cells as a potential mechanism leading to shortcomings in virotherapeutic treatment. In vivo, VSV-GP was tested in a subcutaneous ovarian cancer xenograft mouse model using the A2780 cell line. Treatment led to tumor remission, which was temporary in most mice resulting in tumor recurrance. In an orthotopic xenograft mouse model, intraperitoneal injection of the virus led to significantly prolonged survival compared to untreated animals. In addition, combination therapy of VSV-GP with the JAK1/2-inhibitor ruxolitinib was successfully tested in both models and found to enhance the oncolytic effect. The drug inhibited the signalling pathway induced by type I IFN and could thus be used to inhibit the antiviral innate immune response and enhance intratumoral viral replication. Importantly, despite inhibiting the antiviral response, no toxicity was observed in mice receiving up to 109 pfus (plaque forming units) VSV-GP via intraperitoneal application. In addition, using luciferase expressing VSV-GP, we found no off target tropism with ruxolitinib combination. In conclusion, VSV-GP was tested as a potent oncolytic virus to treat ovarian cancer. Restriction of viral replication due to the innate immune response could be overcome by the combination treatment of VSV-GP with the Jak-1/2 inhibitor ruxolitinib. Citation Format: Janine Kimpel, Carles R. Urbiola, Catherine Dold, Christian Marth, Alexander Muik, Dorothee Holm-von Laer, Guido Wollmann. Innate immunity modulators to enhance oncolytic VSV-GP for the treatment of ovarian cancer [abstract]. In: Proceedings of the Second CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; 2016 Sept 25-28; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2016;4(11 Suppl):Abstract nr B114.

Aim Sedentary behavior poses a serious health risk. Students in particular are highly affected by prolonged, uninterrupted periods of sitting due to routines in everyday university life, such as attending lectures, self-study periods in the library, etc. Whereas university students are mostly young and therefore appear to be healthy, evidence-based consequences of prolonged sitting may come to pass in prospective times. Therefore, primary prevention must be initiated to shield university students from the occurrence of non-communicable diseases (NCDs). Consequently, the study aims to evaluate a messenger-based intervention designed to reduce sedentary time among university students. Subjects and Methods The effectiveness of the intervention was assessed in a randomized controlled trial with a convenience sample of thirty-four German university students. ActivPal devices (Pal Technologies Ltd., Glasgow) were applied to measure sedentary behavior objectively before and after a 3-week intervention of messages to interrupt sedentary time. An additional evaluation of the messages was carried out. Results Sedentary behavior decreased by about one hour in the intervention group. Explorative analysis shows a statistically significant, negative correlation between sedentary time at baseline and the change of sedentary behavior over time in the intervention group (r = − .81) indicating effectiveness of the intervention for the participants with the highest sedentary times at baseline. Additionally, the messages were considered appropriate by the participants. Conclusion A reduction of sedentary time of one hour per day in the intervention group is practically significant. The current investigation had similar findings with prior studies where promising results for the reduction of sedentary behavior were observed through mobile-based interventions. The detected effects of the intervention in this pilot study demonstrate an opportunity for further research in this field.

<p>PDF file - 6330KB, Schematic representation of the recombinant vesicular stomatitis virus (VSV) genomes and its replication potential (S1). rVSV(GP) administration i.c. is associated with marginal inflammation (S2). rVSV(GP) tissue distribution after systemic application is almost consistent with rVSV (S3). rVSV(GP) is comparable to rVSV with regard to its in vitro antitumour efficacy (S4). Replication fitness of rVSV(GP) vs. rVSV in glioma cells (S5). Intratumoural virus administration in s.c. G62 human glioblastoma xenografts leads to productive infection and massive viral burst (S6). U87rfp tumour relapse was not due to OV therapy resistance (S7).</p>