1. ¹Angiogenesis Research Laboratory, Department of Restorative Sciences, University of Michigan School of Dentistry, Ann Arbor, MI, USA
2. ²Department of Immunology, Baylor College of Medicine, Houston, TX, USA
3. ³Department of Pathology, University of Michigan School of Medicine, Ann Arbor, MI, USA

Correspondence: Dr JE Nör, Angiogenesis Research Laboratory, University of Michigan School of Dentistry, 1011 N University, Rm. 2309, Ann Arbor, MI 48109-1078, USA

Received 12 January 2004; Accepted 12 April 2004; Published online 23 December 2004.

Abstract

The activation of an inducible caspase (iCaspase-9) mediates apoptosis of neovascular endothelial cells, and overcomes the prosurvival effect of vascular endothelial growth factor or basic fibroblast growth factor. The potential utilization of direct activation of caspases as an antiangiogenic strategy for treatment of angiogenesis-dependent diseases (eg cancer) requires expression of the inducible caspase primarily in the tumor endothelium. The objective of this work was to develop and characterize a transcriptionally targeted adenoviral vector that mediates expression of iCaspase-9 specifically in neovascular endothelial cells. We observed that adenoviral vectors containing the human VEGFR2 promoter induced reporter gene expression primarily in proliferating human dermal microvascular endothelial cells (HDMEC). HDMEC transduced with recombinant adenoviral vectors containing iCaspase-9 under regulation of the VEGFR2 promoter (Ad-hVEGFR2-iCaspase-9) and exposed to a cell-permeable dimerizer drug (AP20187), presented higher caspase-3 activity and apoptosis than controls (P0.05). Using the SCID Mouse Model of Human Angiogenesis, we observed that local delivery of Ad-hVEGFR2-iCaspase-9 followed by intraperitoneal injection of AP20187 resulted in endothelial cell apoptosis and local ablation of microvessels. We believe that this constitutes the first report of a transcriptionally targeted antiangiogenic adenoviral vector that mediates neovascular disruption upon activation of a caspase-based artificial death switch.