Metal-ion-dependent biological properties of a chelator-derived somatostatin analogue for tumour targeting

Heppeler, Axel; André, João P; Buschmann, Ingeborg; Wang, Xuejuan; Reubi, Jean-Claude; Hennig, Michael; Kaden, Thomas A; Maecke, Helmut R (2008). Metal-ion-dependent biological properties of a chelator-derived somatostatin analogue for tumour targeting. Chemistry - a European journal, 14(10), pp. 3026-34. Weinheim: Wiley-VCH 10.1002/chem.200701264

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Somatostatin-based radioligands have been shown to have sensitive imaging properties for neuroendocrine tumours and their metastases. The potential of [(55)Co(dotatoc)] (dotatoc =4,7,10-tricarboxymethyl-1,4,7,10-tetraazacyclododecane-1-ylacetyl-D-Phe-(Cys-Tyr-D-Trp-Lys-Thr-Cys)-threoninol (disulfide bond)) as a new radiopharmaceutical agent for PET has been evaluated. (57)Co was used as a surrogate of the positron emitter (55)Co and the pharmacokinetics of [(57)Co(dotatoc)] were investigated by using two nude mouse models. The somatostatin receptor subtype (sst1-sst5) affinity profile of [(nat)Co(dotatoc)] on membranes transfected with human somatostatin receptor subtypes was assessed by using autoradiographic methods. These studies revealed that [(57)Co(dotatoc)] is an sst2-specific radiopeptide which presents the highest affinity ever found for the sst2 receptor subtype. The rate of internalisation into the AR4-2J cell line also was the highest found for any somatostatin-based radiopeptide. Biodistribution studies, performed in nude mice bearing an AR4-2J tumour or a transfected HEK-sst2 cell-based tumour, showed high and specific uptake in the tumour and in other sst-receptor-expressing tissues, which reflects the high receptor binding affinity and the high rate of internalisation. The pharmacologic differences between [(57)Co(dotatoc)] and [(67)Ga(dotatoc)] are discussed in terms of the structural parameters found for the chelate models [Co(II)(dota)](2-) and [Ga(III)(dota)](-) whose X-ray structures have been determined. Both chelates show six-fold coordination in pseudo-octahedral arrangements.

Item Type:	Journal Article (Original Article)
Division/Institute:	04 Faculty of Medicine > Service Sector > Institute of Pathology
UniBE Contributor:	Reubi-Kattenbusch, Jean-Claude
Subjects:	500 Science > 570 Life sciences; biology 600 Technology > 610 Medicine & health
ISSN:	0947-6539
ISBN:	18246556
Publisher:	Wiley-VCH
Language:	English
Submitter:	Factscience Import
Date Deposited:	04 Oct 2013 15:02
Last Modified:	05 Dec 2022 14:19
Publisher DOI:	10.1002/chem.200701264
PubMed ID:	18246556
Web of Science ID:	000254872600009
URI:	https://boris.unibe.ch/id/eprint/27067 (FactScience: 101631)