Abstract #1898

Aminocyclopentane- And Aminocyclophexane-Carboxylic Acid Containing Cyclic RGD-DOTA-Gd Conjugates with High Specific Affinity for &[alpha] &[nu] &[beta]3 Integrin as MRI Contrast Agents

In Ok Ko¹, Ji-Ae Park¹, Jung Young Kim¹, Wonho Lee¹, Sang Moo Lim², Kyeong Min Kim¹

¹Molecular Imaging Research Center, Korea Institute of Radiological & Medical Science, Seoul, Korea; ²Department of Nuclear Medicine, Korea Institute of Radiological & Medical Science, Seoul, Korea

We designed two integrin &[alpha]_&[nu] &[beta]3-specific MRI contrast agents, which is an inserted aminocyclopentane (ACP) or amicocyclohexane (ACH)-carboxylic acid into c(RGDK) to improve the binding affinity, and evaluated their tumor targeting efficacy in U87MG tumor bearing mice. Substitution of ACP or ACH in the lead structure c(RGD-ACP-K)-DOTA and c(RGD-ACH-K)-DOTA exhibited much higher binding affinity for &[alpha]_&[nu] &[beta]3 integrin than c(RGDyK). The in vivo MR images of mice obtained with c(RGD-ACP-K)-DOTA-Gd and c(RGD-ACH-K)-DOTA-Gd showed a significant enhancement in the tumor.