Acetylene-bearing 2-[F-18]fluoropyridines [F-18]FPy5yne and PEG-[F-18]FPyKYNE were prepared via efficient nucleophilic heteroaromatic [F-18]fluorination of their corresponding 2-trimethylammoniumpyrdinyl precursors. The prosthetic groups were conjugated to azide- and PEG(3)-modified bombesin(6-14) analogues via copper-catalyzed azide-alkyne cycloaddition couplings to yield mono- and di-mini-PEGylated ligands for PET imaging of the gastrin- releasing peptide receptor. The PEG(3)- and PEG(2)/PEG(3)-bearing F-18 peptides showed decreased lipophilicity relative to an analogous non-mini-PEGylated F-18 peptide. Assessment of water-soluble peptide pharmacokinetics and tumour-targeting capabilities in a mouse model of prostate cancer is currently underway. (c) 2013 Elsevier Ltd. All rights reserved.
Labeling of an Antisense Oligonucleotide with [<sup>18</sup>F]FPy5yne
作者:James A. H. Inkster、Michael J. Adam、Tim Storr、Thomas J. Ruth
DOI:10.1080/15257770903400691
日期:2009.12.7
Functional imaging of gene expression in vivo with short-lived positron emitter F-18 remains an unrealized goal, in part because the long reaction times and challenging protocols typically required to label nucleic acid-based molecular probes with this radionuclide (t(1/2) = 109.8 minutes). To this end, we synthesized prosthetic group 2-[F-18] fluoro-3-(hex-5-ynyloxy) pyridine ([F-18] FPy5yne), used previously to label peptides, and coupled it to an oligodeoxyribonucleotide with F-18 by way of a Cu-I-mediated azide/alkyne cycloaddition reaction. HPLC-purified [F-18]FPy5yne was ligated to a 5'-azide-modified DNA sequence antisense to mdr1 mRNA in the presence of Cu-I-stabilizing ligand tris(benzyltriazolylmethyl) amine and 2,6-lutidine. Non-decay corrected, collected yields of the F-18-labeled oligonucleotide from end-of-bombardment were 3.9% +/- 0.5% (n = 3; 24.6% 0.5% decay corrected). Shortest preparation time was 276 minutes from start of synthesis.