1. ¹Department of Surgery, University of Pittsburgh Cancer Institute, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
2. ²Surgery Branch, National Cancer Institute, NIH, Bethesda, MD, USA
3. ³Department of Hepatobiliary Surgery, First Affiliated Hospital, Sun Yat-Sen University, Guangzhou, Guangdong, China

Correspondence: Dr ZS Guo, Department of Surgery, University of Pittsburgh Cancer Institute, UPCI Research Pavilion, Suite 1.46, 5117 Centre Avenue, Pittsburgh, PA 15213, USA. E-mail: guozs@upmc.edu

Received 28 July 2007; Revised 9 October 2007; Accepted 10 November 2007; Published online 14 December 2007.

Abstract

In this study, we assessed the ability of a highly tumor-selective oncolytic vaccinia virus armed with a yeast cytosine deaminase gene to infect and lyse human and murine ovarian tumors both in vitro and in vivo. The virus vvDD-CD could infect, replicate in and effectively lyse both human and mouse ovarian cancer cells in vitro. In two different treatment schedules involving either murine MOSEC or human A2780 ovarian carcinomatosis models, regional delivery of vvDD-CD selectively targeted tumor cells and ovarian tissue, effectively delaying the development of either tumor or ascites and leading to significant survival advantages. Oncolytic virotherapy using vvDD-CD in combination with the prodrug 5-fluorocytosine conferred an additional long-term survival advantage upon tumor-bearing immunocompetent mice. These findings demonstrate that a tumor-selective oncolytic vaccinia combined with gene-directed enzyme prodrug therapy is a highly effective strategy for treating advanced ovarian cancers in both syngeneic mouse and human xenograft models. Given the biological safety, tumor selectivity and oncolytic potency of this armed oncolytic virus, this dual therapy merits further investigation as a promising new treatment for metastatic ovarian cancer.