Synthesis and in vitro characterization of radioiodinatable benzodiazepines selective for type 1 and type 2 cholecystokinin receptors

Akgün, Eyup; Körner Jachertz, Meike; Gao, Fan; Harikumar, Kaleeckal G; Waser, Beatrice; Reubi, Jean-Claude; Portoghese, Philip S; Miller, Laurence J (2009). Synthesis and in vitro characterization of radioiodinatable benzodiazepines selective for type 1 and type 2 cholecystokinin receptors. Journal of medicinal chemistry, 52(7), pp. 2138-47. Easton, Pa.: American Chemical Society 10.1021/jm801439x

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Radiolabeled antagonists of specific peptide receptors identify a higher number of receptor binding sites than agonists and may thus be preferable for in vivo tumor targeting. In this study, two novel radioiodinated 1,4-benzodiazepines, (S)-1-(3-iodophenyl)-3-(1-methyl-2-oxo-5-phenyl-2,3-dihydro-1H-benzo[e][1,4]diazepin-3-yl)urea (9) and (R)-1-(3-iodophenyl)-3-(1-methyl-2-oxo-5-phenyl-2,3-dihydro-1H-benzo[e][1,4]diazepin-3-yl)urea (7), were developed. They were characterized in vitro as high affinity selective antagonists at cholecystokinin types 1 and 2 (CCK(1) and CCK(2)) receptors using receptor binding, calcium mobilization, and internalization studies. Their binding to human tumor tissues was assessed with in vitro receptor autoradiography and compared with an established peptidic CCK agonist radioligand. The (125)I-labeled CCK(1) receptor-selective compound 9 often revealed a substantially higher amount of CCK(1) receptor binding sites in tumors than the agonist (125)I-CCK. Conversely, the radioiodinated CCK(2) receptor-selective compound 7 showed generally weaker tumor binding than (125)I-CCK. In conclusion, compound 9 is an excellent radioiodinated nonpeptidic antagonist ligand for direct and selective labeling of CCK(1) receptors in vitro. Moreover, it represents a suitable candidate to test antagonist binding to CCK(1) receptor-expressing tumors in vivo.

Item Type:	Journal Article (Original Article)
Division/Institute:	04 Faculty of Medicine > Service Sector > Institute of Pathology
UniBE Contributor:	Körner Jachertz, Meike, Waser, Beatrice, Reubi-Kattenbusch, Jean-Claude
Subjects:	500 Science > 570 Life sciences; biology 600 Technology > 610 Medicine & health
ISSN:	0022-2623
ISBN:	19271701
Publisher:	American Chemical Society
Submitter:	Factscience Import
Date Deposited:	04 Oct 2013 15:08
Last Modified:	05 Dec 2022 14:21
Publisher DOI:	10.1021/jm801439x
PubMed ID:	19271701
Web of Science ID:	000264835800035
URI:	https://boris.unibe.ch/id/eprint/29978 (FactScience: 165576)