High contrast pet imaging of GRPR expression in prostate cancer using cobalt-labeled bombesin antagonist RM26

Bogdan Mitran, Helge Thisgaard, Ulrika Rosenström, Johan Hygum Dam, Mats Larhed, Vladimir Tolmachev, Anna Orlova

Research output: Contribution to journalArticlepeer-review

14 Citations (Scopus)

Abstract

High gastrin releasing peptide receptor (GRPR) expression is associated with numerous cancers including prostate and breast cancer.The aim of the current study was to develop a55Co-labeled PET agent based on GRPR antagonist RM26 for visualization of GRPR-expressing tumors. Labeling with57Co and55Co, stability, binding specificity, and in vitro and in vivo characteristics of57Co-NOTA-PEG2-RM26 were studied.NOTA-PEG2-RM26 was successfully radiolabeled with57Co and55Co with high yields and demonstrated high stability.The radiopeptide showed retained binding specificity to GRPR in vitro and in vivo.57Co-NOTA-PEG2- RM26 biodistribution in mice was characterized by rapid clearance of radioactivity from blood and normal non-GRPR-expressing organs and low hepatic uptake.The clearance was predominantly renal with a low degree of radioactivity reabsorption. Tumor-toblood ratios were approximately 200 (3 h pi) and 1000 (24 h pi).The favorable biodistribution of cobalt-labeled NOTA-PEG2-RM26 translated into high contrast preclinical PET/CT (using55Co) and SPECT/CT (using57Co) images of PC-3 xenografts.The initial biological results suggest that55Co-NOTA-PEG2-RM26 is a promising tracer for PET visualization of GRPR-expressing tumors.

Original languageEnglish
Article number6873684
JournalContrast Media and Molecular Imaging
Volume2017
DOIs
Publication statusPublished - 10 Aug 2017
Externally publishedYes

ASJC Scopus subject areas

  • Radiology Nuclear Medicine and imaging

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