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.