Glu-RGD-bombesin (RGD-BBN) is a heterodimeric peptide that contains motifs recognizing both integrin α(v)β(3) and gastrin releasing peptide receptor (GRPR).
We evaluated here (188)Re (t(1/2)=16.9h) labeled RGD-BBN as a potential agent for radionuclide therapy of prostate cancer. RGD-BBN was conjugated with S-benzoylmercaptoacetylglycylglycyl (MAG(2)), and then labeled with (99m)Tc or (188)Re, respectively. The dual-receptor binding affinity of MAG(2)-RGD-BBN was investigated by a radioligand competition binding assay. Biodistribution study of (188)Re-MAG(2)-RGD-BBN was carried out in normal BALB/c mice and PC-3 human prostate tumor-bearing nude mice. Gamma imaging studies were performed in PC-3 tumor-bearing nude mice. Biodistribution in normal mice showed that both (99m)Tc and (188)Re-labeled MAG(2)-RGD-BBN possessed high pancreas uptake due to the high GRPR expression of this organ. Gamma imaging with both (99m)Tc and (188)Re-labeled RGD-BBN in PC-3 tumor-bearing nude mice demonstrated high tumor uptake. The PC-3 tumors were clearly visible at 1 postinjection, with high contrast to the contralateral background. The use of chelator MAG(2) enables successful and high-yield (99m)Tc and (188)Re radiolabeling of RGD-BBN with favorable tumor targeting specificity. Further optimization may allow potential clinical application of (188)Re-MAG(2)-RGD-BBN for tumor-targeted radionuclide therapy.
Written by:
Cui L, Liu Z, Jin X, Jia B, Li F, Wang F Are you the author?
Medical Isotopes Research Center, Peking University, Beijing 100191, China; Department of Radiation Medicine, School of Basic Medical Sciences, Peking University, Beijing 100191, China
Reference: Nucl Med Biol. 2013 Feb;40(2):182-9
doi: 10.1016/j.nucmedbio.2012.11.002
PubMed Abstract
PMID: 23199569
