1. ¹Carl C. Icahn Center for Gene Therapy and Molecular Medicine, Mount Sinai School of Medicine, New York, NY, USA
2. ²Turku Centre for Biotechnology, University of Turku and Åbo Akademi University, Turku, Finland
3. ³Department of Medical Biochemistry and Molecular Biology, University of Turku, Turku, Finland
4. ⁴Department of Dermatology, University of Turku, Turku, Finland
5. ⁵Division of Medical Genetics, School of Medicine, University of Washington, Seattle, WA, USA
6. ⁶Department of Medicine, University of Turku, Turku, Finland

Correspondence: Dr M Savontaus, Turku Centre for Biotechnology, University of Turku, Tykistökatu 6B, FIN-20520 Turku, Finland. E-mail: mikko.savontaus@btk.utu.fi

Received 25 February 2004; Revised 27 February 2005; Accepted 8 July 2005; Published online 18 August 2005.

Abstract

Targeted antiangiogenic gene therapy is an attractive approach to treat metastatic cancer. However, the relative paucity of the receptors of the commonly used adenovirus serotype 5 in endothelial cells as compared with liver cells undermines the use of this vector for targeting the endothelial cells in tumors. To overcome this problem, we analyzed the ability of a hybrid Ad5/35 virus, where the serotype 5 fiber has been replaced with the fiber from serotype 35, to target tumor vasculature. Infection of human umbilical vein endothelial cells (HUVECs) with Ad5/35 at MOI 120 infected 100% of cells. In contrast, infection with Ad5 at the same MOI infected only 10% HUVECs. Ad5/35 was even more effective in transducing human aortic endothelial cells (HAECs), as infection with Ad5/35 at MOI 3.6 was sufficient to transduce 95% of cells. Gene expression analyses demonstrated that infection of HUVECs and HAECs with Ad5/35 resulted in between 1 and 3 orders of magnitude higher gene expression than infection with Ad5. Furthermore, various liver-derived cells were less infectable with Ad5/35 than Ad5, indicating a favorable toxicity profile for this virus. In a rat colon carcinoma tumor model, Ad5 was located mainly in the liver parenchyma after hepatic artery administration. In contrast, Ad5/35 was found only in the angiogenesis-rich border region of the tumor. Double immunostaining revealed that Ad5/35 colocalized with CD31 and Flk-1 positive endothelial cells. These results indicate that Ad5/35 may be useful in anticancer strategies targeting tumor endothelial cells.