Gadolinium Complex of (125)I/(127)I-RGD-DOTA Conjugate as a Tumor-Targeting SPECT/MR Bimodal Imaging Probe

Ji-Ae Park; Jung Young Kim; Yong Jin Lee; Wonho Lee; Sang Moo Lim; Tae-Jeong Kim; Jeongsoo Yoo; Yongmin Chang; Kyeong Min Kim

doi:10.1021/ml3003499

Gadolinium Complex of (125)I/(127)I-RGD-DOTA Conjugate as a Tumor-Targeting SPECT/MR Bimodal Imaging Probe

ACS Med Chem Lett. 2012 Dec 17;4(2):216-9. doi: 10.1021/ml3003499. eCollection 2013 Feb 14.

Authors

Ji-Ae Park¹, Jung Young Kim¹, Yong Jin Lee¹, Wonho Lee¹, Sang Moo Lim¹, Tae-Jeong Kim², Jeongsoo Yoo³, Yongmin Chang³, Kyeong Min Kim¹

Affiliations

¹ Molecular Imaging Research Center and Department of Nuclear Medicine, Korea Institute of Radiological and Medical Sciences , Seoul 139-706, Republic of Korea.
² Department of Applied Chemistry, Kyungpook National University , Daegu 702-701, Republic of Korea.
³ Department of Molecular Medicine, Kyungpook National University , Daegu 700-422, Republic of Korea.

Abstract

The work describes the synthesis and in vivo application of [Gd(L)(H2O)]·xH2O, where L is a ((125)I/(127)I-RGD)- DOTA conjugate, as a tumor-targeting SPECT/MR bimodal imaging probe. Here, ((125)I/(127)I-RGD)-DOTA signifies a "cocktail mixture" of radioisotopic (1a, L = (125)I-RGD-DOTA) and natural (1b, L = (127)I-RGD-DOTA) Gd complexes. The two complexes are chemically equivalent as revealed by HPLC, and their cocktail mixture exhibits the integrin-specific tumor enhancement, demonstrating that they constitute essentially a single bimodal imaging probe. Employment of a cocktail mixture thus proves to be a sole and practical approach to overcome the sensitivity difference problem between MRI and SPECT.

Keywords: RGD peptide; SPECT/MR; dual modality; small molecule; tumor targeting.