title: Activation of cytotoxic and regulatory functions of NK cells by Sindbis viral vectors.
abstract: Oncolytic viruses (OVs) represent a relatively novel anti-cancer modality. Like other new cancer treatments, effective OV therapy will likely require combination with conventional treatments. In order to design combinatorial treatments that work well together, a greater scrutiny of the mechanisms behind the individual treatments is needed. Sindbis virus (SV) based vectors have previously been shown to target and kill tumors in xenograft, syngeneic, and spontaneous mouse models. However, the effect of SV treatment on the immune system has not yet been studied. Here we used a variety of methods, including FACS analysis, cytotoxicity assays, cell depletion, imaging of tumor growth, cytokine blockade, and survival experiments, to study how SV therapy affects Natural Killer (NK) cell function in SCID mice bearing human ovarian carcinoma tumors. Surprisingly, we found that SV anti-cancer efficacy is largely NK cell-dependent. Furthermore, the enhanced therapeutic effect previously observed from Sin/IL12 vectors, which carry the gene for interleukin 12, is also NK cell dependent, but works through a separate IFNγ-dependent mechanism, which also induces the activation of peritoneal macrophages. These results demonstrate the multimodular nature of SV therapy, and open up new possibilities for potential synergistic or additive combinatorial therapies with other treatments.
authors.affiliation: Gene Therapy Center, Cancer Institute and Department of Pathology, New York University School of Medicine, New York, New York, United States of America.
authors.forename: Tomer
authors.initials: T
authors.lastname: Granot
authors.forename: Lisa
authors.initials: L
authors.lastname: Venticinque
authors.forename: Jen-Chieh
authors.initials: JC
authors.lastname: Tseng
authors.forename: Daniel
authors.initials: D
authors.lastname: Meruelo
mesh_terms: D000818:Animals; D002452:Cell Count; D045744:Cell Line, Tumor; D002471:Cell Transformation, Neoplastic / Q000276:immunology; D006224:Cricetinae; D003602:Cytotoxicity, Immunologic / Q000235:genetics / Q000276:immunology*; D005260:Female; D005802:Genes, MHC Class II / Q000235:genetics; D005822:Genetic Vectors / Q000235:genetics* / Q000276:immunology; D006801:Humans; D007371:Interferon-gamma / Q000378:metabolism; D018664:Interleukin-12 / Q000235:genetics; D007694:Killer Cells, Natural / Q000166:cytology / Q000276:immunology* / Q000378:metabolism / Q000637:transplantation; D007763:Lac Operon / Q000235:genetics; D017737:Macrophages, Peritoneal / Q000276:immunology / Q000378:metabolism; D051379:Mice; D050130:Oncolytic Virotherapy; D010537:Peritoneum / Q000276:immunology / Q000378:metabolism; D012845:Sindbis Virus / Q000235:genetics* / Q000276:immunology* / Q000502:physiology; D015854:Up-Regulation / Q000276:immunology
chemical_list: D018664:Interleukin-12; D007371:Interferon-gamma