Vascular-targeted nanoparticles for molecular imaging and therapy

In summary, we have shown in vivo imaging of angiogenic tumors using anti-avb3-targeted polymerized vesicles comprised of the murine antibody LM609 attached to PVs labeled with the MR contrast agent gadolinium (Gd) in the V2 carcinoma model in rabbits. MRI studies using this targeted contrast agent revealed large areas of avb3 integrin expression in tumor-associated vasculature that conventional MRI failed to show. Immunohistochemical staining of the tumors showed colocalization of the ACPVs with the avb3 integrin in the tumor blood vessels without penetration into the surrounding tumor tissue. Other investigators have used microemulsions conjugated to an antibody targeted against avb3 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.