545 PEPTIDE RECEPTOR TARGETING IS SUPERIOR TO METABOLIC TARGETING FOR IN VIVO IMAGING OF HUMAN PROSTATE CANCER XENOGRAFTS

Abstract

You have accessJournal of UrologyProstate Cancer: Basic Research IV1 Apr 2010545 PEPTIDE RECEPTOR TARGETING IS SUPERIOR TO METABOLIC TARGETING FOR IN VIVO IMAGING OF HUMAN PROSTATE CANCER XENOGRAFTS Rogier P.J. Schroeder, Saskia C. Berndsen, Corine de Ligt, Susanne Reneman, Eric P. Krenning, Chris Bangma, Marion de Jong, and Wytske M. van Weerden Rogier P.J. SchroederRogier P.J. Schroeder More articles by this author , Saskia C. BerndsenSaskia C. Berndsen More articles by this author , Corine de LigtCorine de Ligt More articles by this author , Susanne RenemanSusanne Reneman More articles by this author , Eric P. KrenningEric P. Krenning More articles by this author , Chris BangmaChris Bangma More articles by this author , Marion de JongMarion de Jong More articles by this author , and Wytske M. van WeerdenWytske M. van Weerden More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2010.02.765AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Prostate cancer (PC) is a major health problem in Western men. Accurate staging and monitoring of PC are crucial steps in management of disease. Conventional imaging techniques used for PC may be improved by nuclear imaging based on positron emission tomography (PET) or single positron emission tomography (SPECT) modalities. We propose that peptide receptor based nuclear imaging using radiolabeled bombesin (BN) - a peptide that binds with high affinity to gastrin-releasing peptide receptors (GRPR) which are overexpressed on PC cell membranes - is a more sensitive approach to detect PC than metabolic targeted imaging using radiolabeled choline. Objective: comparison of BN receptor targeting and choline-based metabolic targeting for imaging of PC-bearing mice. METHODS The BN-analogue Gallium-68-DOTA-AMBA (68Ga-AMBA) was used to perform PET and biodistribution studies in VCaP- and PC-3-bearing xenografts. For comparison the choline derivative, methylcholine, labeled with Fluor-18 (18F-CH) was used. PET scanning started directly post injection (p.i.) and was done in each mouse with both tracers performed at separate days. Images were reconstructed and quantitatively analyzed. Tumors and selected organs from biodistribution were measured in a gamma counter and uptake was calculated as % of injected dose per gram tissue (%ID/g). RESULTS All xenograft tumors could be visualised by PET using 68Ga-AMBA. Using 18F-CH, PET showed less contrast between tumor and background. Quantitative analyses of the dynamic PET scans showed a fast tumor uptake and high retention for both tracers. 68Ga-AMBA reached a plateau after at about 12 min and remained stable for at least 60 min. Biodistribution data indicated a total tumor uptake of 68Ga-AMBA of 9.5 ± 4.8 %ID/g which was significantly higher than that of 18F-CH (2.1 ± 0.4 %ID/g). Apart from the GRPR-expressing colon and pancreas, all organs had significantly lower uptake after 68Ga-AMBA as compared to 18F-CH injection. The absolute radioactivity in circulation was low (≤ 0.8 %ID/g) for both tracers at endpoint; 30 and 60 min p.i., for 18F-CH and 68Ga-AMBA respectively. Results from biodistribution and quantitative PET analyses were similar. CONCLUSIONS PET scanning and biodistribution studies indicate that tumor uptake of 68Ga–AMBA was higher while overall background activity was lower as compared to 18F-CH in PC-bearing mice. These data suggest that peptide receptor mediated PET imaging using BN-based peptides is superior to metabolic PET using choline-based tracers for visualization and imaging of PC. Rotterdam, Netherlands© 2010 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 183Issue 4SApril 2010Page: e214 Advertisement Copyright & Permissions© 2010 by American Urological Association Education and Research, Inc.MetricsAuthor Information Rogier P.J. Schroeder More articles by this author Saskia C. Berndsen More articles by this author Corine de Ligt More articles by this author Susanne Reneman More articles by this author Eric P. Krenning More articles by this author Chris Bangma More articles by this author Marion de Jong More articles by this author Wytske M. van Weerden More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...