We have discussed the impact of molecular imaging on clinical and preclinical medicine. We have presented the potential problems of delivering the effective therapeutic dose and the properties that can help contribute to the
drug efficacy. The rationale for the design of new
antiangiogenic agents that can be used for imaging and
therapy was presented. Finally, results from imaging and targeted nanoparticle based
therapies were presented. In vivo imaging of angiogenic
tumors using anti-alpha(v)beta3 -targeted polymerized vesicles composed of the murine antibody LM609 attached to NPs labeled with the MR
contrast agent gadolinium in the V2
carcinoma model in rabbits. MRI studies using this targeted
contrast agent revealed large areas of alpha(v)
beta3 integrin expression in
tumor-associated vasculature that conventional MRIs failed to show. Other investigators have used microemulsions conjugated to an antibody targeted against alpha(v)beta as imaging agents. These materials also show contrast enhancement of
tumor vasculature undergoing angiogenesis. Other markers, such as the
PECAM-1 (CD-31),
VCAM-1 (CD54) and
VEGF receptor (flk-1), have been shown to be upregulated on
tumor endothelium and associated with angiogenesis but have not been used in imaging studies. Furthermore, by modification of the NPs, we were able to use this imaging agent as an antiangiogenic gene delivery system. The results from these studies are very promising and are being further pursued.