434. Coxsackievirus A11 Induces Robust Oncolytic Activity Against Human Non-Small Cell Lung Cancer Cells With Immunostimulatory Properties
Authors: Miyako Sagara, Hiroyuki Inoue, Masaki Kuroda, Shohei Miyamoto, Hisanobu Ogata, Yuki Nakano, Beibei Wang, Yuto Takishima, Kazunari Yamada, Hiroyuki Shimizu, Yoichi Nakanishi, Kenzaburo Tani
Journal: Molecular Therapy (2015)

Non-small cell lung cancer (NSCLC) is the leading cause of cancer-related mortality worldwide. Innovative treatment is therefore required to improve overall survival rates of advanced NSCLC. Oncolytic virotherapy using enteroviruses emerges as a promising anticancer strategy. As therapeutic advantages, enteroviruses immediately induce robust oncolytic activity and do not have oncogenes that may lead to tumorigenesis. Herein, we focused on enterovirus strain of coxsackievirus A11 (CVA11) to assess its oncolytic activity in a panel of human NSCLC cell lines because it has low pathogenicity but possesses broad oncolytic activity in our first screening assay using 38 enteroviruses. We found that CVA11 infection exhibited extensive oncolytic activity in 7 of 7 human NSCLC cell lines in a MOI-dependent manner, whereas it displayed no cytotoxicity in HaCaT normal human keratinocyte cell line. As CVA11 belongs to the species human enterovirus C that utilizes ICAM-1 for cell entry, we investigated the correlation of ICAM-1 expression levels and CVA11-mediated cytotoxicity, revealing a tendency that NSCLC cells expressing higher levels of ICAM-1 exhibited higher CVA11-mediated cytotoxicity. Gain-of-function assay showed that RD cells overexpressing human ICAM-1 acquired a susceptibility to CVA11 infection resulting in robust cellular destruction even at a low MOI of 0.01, whereas parental RD cells with negligible ICAM-1 showed no cytotoxicity, illustrating that ICAM-1 molecule could be one of cell surface receptors for CVA11 infection. To dissect the role of apoptotic cell death in CVA11-mediated oncolysis, we assessed the impact of pretreatment with Z-VAD, a pan-Caspase inhibitor which prevents apoptosis of the CVA11-driven cytotoxicity. Apoptosis partially but significantly was demonstrated to contribute to the CVA11-driven oncolysis in NSCLC cell lines. Furthermore, our results of xenograft models using nude mice transplanted with human NSCLC tumors revealed that intratumoral CVA11 administrations significantly suppressed the outgrowth of preestablished xenografts and prolonged the survival of the CVA11-treated mice. Of note, all mice treated with CVA11 showed no significant changes of body weight during the treatment. Finally we investigated whether CVA11 infection could induce immunogenic cell death by releasing DAMPs such as calreticulin (CRT) exposure and HMGB1 translocation. Of note, CVA11 infection induced abundant surface exposure of CRT in a time dependent manner and robust release of HMGB1 from the nuclei of NSCLC cells into the cytosol. We showed that CVA11 displayed remarkable oncolytic activity against human NSCLC with tolerability and immunostimulatory properties indicating a promising oncolytic therapeutics against NSCLC. Further preclinical and clinical studies are required for the translation of this new modality to clinical use.