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Multimerization results in formation of re-bindable metabolites: A proof of concept study with FSC-based minigastrin imaging probes targeting CCK2R expression

Positron emission tomography (PET) with radiolabelled peptide-based tracers has attracted great interest in oncology over the past decades. The success of imaging is closely related to sufficient uptake of the radiotracer in malignant tissue and for this sufficient biological half-life, particularly...

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Autores principales: Summer, Dominik, Kroess, Andrea, Woerndle, Rudolf, Rangger, Christine, Klingler, Maximilian, Haas, Hubertus, Kremser, Leopold, Lindner, Herbert H., von Guggenberg, Elisabeth, Decristoforo, Clemens
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Public Library of Science 2018
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6066219/
https://www.ncbi.nlm.nih.gov/pubmed/30059514
http://dx.doi.org/10.1371/journal.pone.0201224
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author Summer, Dominik
Kroess, Andrea
Woerndle, Rudolf
Rangger, Christine
Klingler, Maximilian
Haas, Hubertus
Kremser, Leopold
Lindner, Herbert H.
von Guggenberg, Elisabeth
Decristoforo, Clemens
author_facet Summer, Dominik
Kroess, Andrea
Woerndle, Rudolf
Rangger, Christine
Klingler, Maximilian
Haas, Hubertus
Kremser, Leopold
Lindner, Herbert H.
von Guggenberg, Elisabeth
Decristoforo, Clemens
author_sort Summer, Dominik
collection PubMed
description Positron emission tomography (PET) with radiolabelled peptide-based tracers has attracted great interest in oncology over the past decades. The success of imaging is closely related to sufficient uptake of the radiotracer in malignant tissue and for this sufficient biological half-life, particularly in the bloodstream, is mandatory. Fast enzymatic degradation during circulation leading to insufficient imaging abilities of peptide-based radioligands remains a major issue. The design of multimeric constructs, bearing multiple targeting moieties, has been widely applied to improve target interaction. This concept may also be applied to prolong the biological half-life of peptide-based radiopharmaceuticals as enzymatic degradation can result in formation of metabolites still capable to interact with the target binding site. In this study we aimed to identify such metabolites and therefore we utilized the siderophore-based bifunctional chelator fusarinine C (FSC) for the design of novel mono- and multimeric constructs, bearing minigastrin (MG) analogues as targeting moieties to address cholecystokinin-2 receptors (CCK2R) which are overexpressed in a variety of cancerous diseases and are well known for fast enzymatic degradation, particularly for truncated des-(Glu)(5)-MG members, such as MG11. FSC-based imaging probes were radiolabelled with gallium-68 and characterized in vitro (logD, protein binding, affinity and cell-uptake studies, stability and metabolite studies, as well as generation of corresponding metabolites by artificial enzymatic degradation) and in vivo (biodistribution in A431-CCK2R/A431-mock tumour xenografted BALB/c nude mice and stability in blood of living BALB/c mice and analysis of corresponding organ homogenates and urine to identify degradation products). In summary, multimerization was accompanied by partial improvement towards targeting abilities. Identified metabolites formed by artificial enzymatic cleavage of trimeric FSC-MG conjugates in vitro contained intact binding sequences for the receptor. Furthermore, the (68)Ga-labelled trimers exhibiting increasing uptake of radioligand in tumour tissue over time and improved in vivo stability in blood samples of living animals of the trimers compared to corresponding mono- and dimers, strongly supporting our hypothesis.
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spelling pubmed-60662192018-08-10 Multimerization results in formation of re-bindable metabolites: A proof of concept study with FSC-based minigastrin imaging probes targeting CCK2R expression Summer, Dominik Kroess, Andrea Woerndle, Rudolf Rangger, Christine Klingler, Maximilian Haas, Hubertus Kremser, Leopold Lindner, Herbert H. von Guggenberg, Elisabeth Decristoforo, Clemens PLoS One Research Article Positron emission tomography (PET) with radiolabelled peptide-based tracers has attracted great interest in oncology over the past decades. The success of imaging is closely related to sufficient uptake of the radiotracer in malignant tissue and for this sufficient biological half-life, particularly in the bloodstream, is mandatory. Fast enzymatic degradation during circulation leading to insufficient imaging abilities of peptide-based radioligands remains a major issue. The design of multimeric constructs, bearing multiple targeting moieties, has been widely applied to improve target interaction. This concept may also be applied to prolong the biological half-life of peptide-based radiopharmaceuticals as enzymatic degradation can result in formation of metabolites still capable to interact with the target binding site. In this study we aimed to identify such metabolites and therefore we utilized the siderophore-based bifunctional chelator fusarinine C (FSC) for the design of novel mono- and multimeric constructs, bearing minigastrin (MG) analogues as targeting moieties to address cholecystokinin-2 receptors (CCK2R) which are overexpressed in a variety of cancerous diseases and are well known for fast enzymatic degradation, particularly for truncated des-(Glu)(5)-MG members, such as MG11. FSC-based imaging probes were radiolabelled with gallium-68 and characterized in vitro (logD, protein binding, affinity and cell-uptake studies, stability and metabolite studies, as well as generation of corresponding metabolites by artificial enzymatic degradation) and in vivo (biodistribution in A431-CCK2R/A431-mock tumour xenografted BALB/c nude mice and stability in blood of living BALB/c mice and analysis of corresponding organ homogenates and urine to identify degradation products). In summary, multimerization was accompanied by partial improvement towards targeting abilities. Identified metabolites formed by artificial enzymatic cleavage of trimeric FSC-MG conjugates in vitro contained intact binding sequences for the receptor. Furthermore, the (68)Ga-labelled trimers exhibiting increasing uptake of radioligand in tumour tissue over time and improved in vivo stability in blood samples of living animals of the trimers compared to corresponding mono- and dimers, strongly supporting our hypothesis. Public Library of Science 2018-07-30 /pmc/articles/PMC6066219/ /pubmed/30059514 http://dx.doi.org/10.1371/journal.pone.0201224 Text en © 2018 Summer et al http://creativecommons.org/licenses/by/4.0/ This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/) , which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
spellingShingle Research Article
Summer, Dominik
Kroess, Andrea
Woerndle, Rudolf
Rangger, Christine
Klingler, Maximilian
Haas, Hubertus
Kremser, Leopold
Lindner, Herbert H.
von Guggenberg, Elisabeth
Decristoforo, Clemens
Multimerization results in formation of re-bindable metabolites: A proof of concept study with FSC-based minigastrin imaging probes targeting CCK2R expression
title Multimerization results in formation of re-bindable metabolites: A proof of concept study with FSC-based minigastrin imaging probes targeting CCK2R expression
title_full Multimerization results in formation of re-bindable metabolites: A proof of concept study with FSC-based minigastrin imaging probes targeting CCK2R expression
title_fullStr Multimerization results in formation of re-bindable metabolites: A proof of concept study with FSC-based minigastrin imaging probes targeting CCK2R expression
title_full_unstemmed Multimerization results in formation of re-bindable metabolites: A proof of concept study with FSC-based minigastrin imaging probes targeting CCK2R expression
title_short Multimerization results in formation of re-bindable metabolites: A proof of concept study with FSC-based minigastrin imaging probes targeting CCK2R expression
title_sort multimerization results in formation of re-bindable metabolites: a proof of concept study with fsc-based minigastrin imaging probes targeting cck2r expression
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6066219/
https://www.ncbi.nlm.nih.gov/pubmed/30059514
http://dx.doi.org/10.1371/journal.pone.0201224
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