Investigation of Fluorine-18 Labelled Peptides for Binding to Cholecystokinin-2 Receptors with High Affinity
Details
Publication Year 2022,Volume 28,Issue #1,Page 6
Journal Title
International Journal of Peptide Research and Therapeutics
Publication Type
Research article
Abstract
Many cancers of neuroendocrine origin overexpress cholecystokinin-2 receptors (CCK-2R) including medullary thyroid cancer, small cell lung cancer and other lung carcinoids. Fluorine-18 labelled peptides targeting CCK-2R enable direct visualization and quantification of this receptor in vivo using positron emission tomography imaging. CP04 1 and MG11 2 are two previously described truncated peptides derived from the native CCK-2R hormone ligand, gastrin. The N-terminus of the MG11 2 octopeptide was chemically modified with various fluorine containing aromatic (4-fluorobenzoate), heterocyclic (6-fluoronicotinate) and aliphatic (2-fluoropropionate) moieties. To assess the impact these modifications had on CCK-2R binding, ligand-binding assays were conducted using A431 cells overexpressing human CCK-2R. MG11 2 modified by 4-fluorobenzoate (FB-MG11 3) demonstrated the highest binding affinity (0.20 nM) followed by MG11 2 modified by 6-fluoronicotinate (FNic-MG11 4; 0.74 nM) and 2-fluoropropionate (FP-MG11 5; 1.80 nM), respectively. Whilst indirect labelling of MG11 2 using fluorine-18 labelled activated esters of fluorobenzoate and 6-fluoronicotinate was unsuccessful, direct fluorine-18 labelling at the N-terminus modified with 6-nitronicotinate afforded a 47.6% radiochemical yield of [18F]FNic-MG11. Unfortunately, [18F]FNic-MG11 4 was chemically unstable, decomposing slowly through defluorination, thereby impeding any further work with this radiotracer.
Department(s)
Cancer Imaging
Open Access at Publisher's Site
https://doi.org/10.1007/s10989-021-10310-z
Terms of Use/Rights Notice
Refer to copyright notice on published article.


Creation Date: 2024-12-20 02:39:28
Last Modified: 2024-12-20 02:40:52

© 2024 The Walter and Eliza Hall Institute of Medical Research. Access to this website is subject to our Privacy Policy and Terms of Use

An error has occurred. This application may no longer respond until reloaded. Reload 🗙