Minute dosages of ανβ3-targeted fumagillin nanoparticles impair Vx-2 tumor angiogenesis and development in rabbits

Fumagillin suppresses angiogenesis in cancer models and clinical trials, but it is associated with neurotoxicity at systemic doses. In this study, alpha(nu)beta(3)-targeted fumagillin nanoparticles were used to suppress the neovasculature and inhibit Vx-2 adenocarcinoma development using minute drug doses. Tumorbearing rabbits were treated on days 6, 9, and 12 postimplantation with alpha(nu)beta(3)-targeted fumagillin nanoparticles (30 mu g/kg), alpha(nu)beta(3)-targeted nanoparticles without drug, nontargeted fumagillin nanoparticles (30 mu g/kg) or saline. On day 16, MRI was performed with alpha(nu)beta(3)-targeted paramagnetic nanoparticles to quantify tumor size and assess neovascularity. Tumor volume was reduced among rabbits receiving alpha(nu)beta(3)-targeted fumagillin nanoparticles (470 +/- 120 mm(3)) compared with the three control groups: nontargeted fumagillin nanoparticles (1370 +/- 300 mm3, P<0.05), alpha(nu)beta(3)-targeted nanoparticles without drug (1080 +/- 180 mm(3), P<0.05) and saline (980 +/- 80 mm(3), P<0.05). MR molecular imaging of control rabbits ( no fumagillin) revealed a predominant peripheral distribution of neovascularity representing 7.2% of the tumor rim volume, which decreased to 2.8% (P<0.05) with alpha(nu)beta(3)-targeted fumagillin nanoparticle treatment. Microscopically, the tumor parenchyma tended to show T-cell infiltration after targeted fumagillin treatment, which was not appreciated in control animals. These results suggest that alpha(nu)beta(3)-targeted fumagillin nanoparticles could provide a safe and effective means to deliver MetAP2 inhibitors alone or in combination with cytotoxic or immunotherapy.