Abstract
Purpose
Stability of radiolabelled cholecystokinin 2 (CCK2) receptor targeting peptides has been a major limitation in the use of such radiopharmaceuticals especially for targeted radionuclide therapy applications, e.g. for treatment of medullary thyroid carcinoma (MTC). The purpose of this study was to compare the in vitro stability of a series of peptides binding to the CCK2 receptor [selected as part of the COST Action on Targeted Radionuclide Therapy (BM0607)] and to identify major cleavage sites.
Methods
Twelve different 1,4,7,10-tetraazacyclododecane-N,N′,N′′,N′′′-tetraacetic acid (DOTA)-minigastrin/CCK conjugates were provided within an European COST Action (BM0607) by different laboratories and radiolabelled with 177Lu. Their in vitro stabilities were tested in fresh human serum. Radiochemical yields (RCY) and intact radioligands for half-life calculations were determined by radio-HPLC. Matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOF MS) analysis of metabolites was performed to identify cleavage products using conjugates labelled with excess stable natLu, incubated in serum at 37°C. Urine metabolite analysis after injection in normal mice was performed by radio-HPLC analysis.
Results
Variable stability in human serum was found for the different peptides with calculated half-lives between 4.5 ± 0.1 h and 198 ± 0.1 h (n = 2). In urine of normal mice only metabolised peptide fragments were detected even at short times after injection for all peptides. MALDI-TOF MS revealed a major cleavage site of all minigastrin derivatives between Asp and Phe-NH2 at the C-terminal end.
Conclusion
Development of CCK2 receptor ligands especially for therapeutic purposes in patients with MTC or small cell lung cancer (SCLC) is still ongoing in different laboratories. This comparative study provided valuable insight into the importance of biological stability especially in the context of other results of this comparative trial within the COST Action BM0607.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Breeman WA, Kwekkeboom DJ, de Blois E, de Jong M, Visser TJ, Krenning EP. Radiolabelled regulatory peptides for imaging and therapy. Anticancer Agents Med Chem 2007;7(3):345–57.
Reubi JC, Maecke HR. Peptide-based probes for cancer imaging. J Nucl Med 2008;49(11):1735–8.
Behr TM, Jenner N, Radetzky S, Béhé M, Gratz S, Yücekent S, et al. Targeting of cholecystokinin-B/gastrin receptors in vivo: preclinical and initial clinical evaluation of the diagnostic and therapeutic potential of radiolabelled gastrin. Eur J Nucl Med 1998;25:424–30.
de Jong M, Bakker WH, Bernard BF, Valkema R, Kwekkeboom DJ, Reubi JC, et al. Preclinical and initial clinical evaluation of 111In-labeled nonsulfated CCK8 analog: a peptide for CCK-B receptor-targeted scintigraphy and radionuclide therapy. J Nucl Med 1999;40:2081–7.
Reubi JC, Schaer JC, Waser B. Cholecystokinin (CCK)-A and CCK-B/gastrin receptors in human tumors. Cancer Res 1997;57(7):1377–86.
Behr TM, Béhé MP. Cholecystokinin-B/Gastrin receptor-targeting peptides for staging and therapy of medullary throid cancer and other cholecystokinin-B receptor-expressing malignancies. Semin Nucl Med 2002;32(2):97–109.
Aloj L, Caracò C, Panico M, Zannetti A, Del Vecchio S, Tesauro D, et al. In vitro and in vivo evaluation of 111In-DTPAGlu-G-CCK8 for cholecystokinin-B receptor imaging. J Nucl Med 2004;45(3):485–94.
von Guggenberg E, Béhé M, Behr TM, Saurer M, Seppi T, Decristoforo C. 99mTc-labeling and in vitro and in vivo evaluation of HYNIC- and (Nalpha-His)acetic acid-modified [D-Glu1]-minigastrin. Bioconjug Chem 2004;15(4):864–71.
Nock BA, Maina T, Béhé M, Nikolopoulou A, Gotthardt M, Schmitt JS, et al. CCK-2/gastrin receptor-targeted tumor imaging with (99m)Tc-labeled minigastrin analogs. J Nucl Med 2005;46(10):1727–36.
Mather SJ, McKenzie AJ, Sosabowski JK, Morris TM, Ellison D, Watson SA. Selection of radiolabeled gastrin analogs for peptide receptor-targeted radionuclide therapy. J Nucl Med 2007;48(4):615–22.
Breeman WA, Fröberg AC, de Blois E, van Gameren A, Melis M, de Jong M, et al. Optimised labeling, preclinical and initial clinical aspects of CCK-2 receptor-targeting with 3 radiolabeled peptides. Nucl Med Biol 2008;35(8):839–49.
Roosenburg S, Laverman P, Joosten L, Eek A, Oyen WJ, de Jong M, et al. Stabilized (111)In-labeled sCCK8 analogues for targeting CCK2-receptor positive tumors: synthesis and evaluation. Bioconjug Chem 2010;21(4):663–70.
Görges R, Kahaly G, Müller-Brand J, Mäcke H, Roser HW, Bockisch A. Radionuclide-labeled somatostatin analogues for diagnostic and therapeutic purposes in nonmedullary thyroid cancer. Thyroid 2001;11(7):647–59.
Aloj L, Morelli G. Design, synthesis and preclinical evaluation of radiolabeled peptides for diagnosis and therapy. Curr Pharm Des 2004;10(24):3009–31.
Gotthardt M, Boermann OC, Behr TM, Béhé MP, Oyen WJ. Development and clinical application of peptide-based radiopharmaceuticals. Curr Pharm Des 2004;10(24):2951–63.
de Jong M, Verwijnen SM, de Visser M, Kwekkeboom DJ, Valkema R, Krenning EP. Peptides for radionuclide therapy. In: Stigbrand T, Carlsson J, Adams GP, editors. Targeted radionuclide tumor therapy, biological aspects. New York: Springer; 2008. p. 117–44.
Milenic DE, Garmestani K, Chappell LL, Dadachova E, Yordanov A, Ma D, et al. In vivo comparison of macrocyclic and acyclic ligands for radiolabeling of monoclonal antibodies with 177Lu for radioimmunotherapeutic applications. Nucl Med Biol 2002;29(4):431–42.
Harrison A, Walker CA, Parker D, Jankowski KJ, Cox JP, Craig AS, et al. The in vivo release of 90Y from cyclic and acyclic ligand-antibody conjugates. Int J Rad Appl Instrum B 1991;18:469–76.
Liu S, Edwards DS. Bifunctional chelators for therapeutic lanthanide radiopharmaceuticals. Bioconjug Chem 2001;12:7–34.
Good S, Walter MA, Waser B, Wang X, Müller-Brand J, Béhé MP, et al. Macrocyclic chelator-coupled gastrin-based radiopharmaceuticals for targeting of gastrin receptor-expressing tumours. Eur J Nucl Med Mol Imaging 2008;35(10):1868–77.
Werle M, Bernkop-Schnürch A. Strategies to improve plasma half life time of peptide and protein drugs. Amino Acids 2006;30(4):351–67.
Adessi C, Soto C. Converting a peptide into a drug: strategies to improve stability and bioavailability. Curr Med Chem 2002;9(9):963–78.
Ocak M, Helbok A, von Guggenberg E, Ozsoy Y, Kabasakal L, Kremser L, et al. Influence of biological assay conditions on stability assessment of radiometal-labelled peptides exemplified using a 177Lu-DOTA-minigastrin derivative. Nucl Med Biol 2011;38(2):171–9.
Konkoy CS, Davis TP. Ectoenzymes as sites of peptide regulation. Trends Pharmacol Sci 1996;17(8):288–94.
Pauwels S, Najdovski T, Dimaline R, Lee CM, Deschodt-Lanckman M. Degradation of human gastrin and CCK by endopeptides 24.11: differential behaviour of the sulphated and unsulphated peptides. Biochim Biophys Acta 1989;996(1–2):82–8.
Martinez J, Rodriguez M, Bali JP, Laur J. Phenethyl ester derivative analogues of the C-terminal tetrapeptide of gastrin as potent gastrin antagonists. J Med Chem 1986;29(11):2201–6.
Acknowledgement
The authors wish to thank Dr. Leopold Kremser from Division of Clinical Biochemistry - Protein Micro-Analysis Facility, Biocenter, and Innsbruck Medical University for MALDI-TOF MS analyses. The authors also wish to thank the nurses of the Department of Nuclear Medicine of the Innsbruck Medical University for taking blood samples from one of the volunteering authors during the study, and Elisabeth von Guggenberg for her critical review of the manuscript. This work was part of COST Action BM0607 “Targeted Radionuclide Therapy”. Part of the study was supported by Turkish Scientific and Research Council (TUBITAK) Project No. 108S144.
Conflicts of interest
None.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Ocak, M., Helbok, A., Rangger, C. et al. Comparison of biological stability and metabolism of CCK2 receptor targeting peptides, a collaborative project under COST BM0607. Eur J Nucl Med Mol Imaging 38, 1426–1435 (2011). https://doi.org/10.1007/s00259-011-1818-9
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s00259-011-1818-9