18F-AmBF3-MJ9: A novel radiofluorinated bombesin derivative for prostate cancer imaging

https://doi.org/10.1016/j.bmc.2015.02.009Get rights and content
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Abstract

A novel radiofluorinated derivative of bombesin, 18F-AmBF3-MJ9, was synthesized and evaluated for its potential to image prostate cancer by targeting the gastrin releasing peptide receptor (GRPR). AmBF3-MJ9 was prepared from an ammoniomethyl-trifluoroborate (AmBF3) conjugated alkyne 2 and azidoacetyl-MJ9 via a copper-catalyzed click reaction, and had good binding affinity for GRPR (Ki = 0.5 ± 0.1 nM). The 18F-labeling was performed via a facile one-step 18F–19F isotope exchange reaction, and 18F-AmBF3-MJ9 was obtained in 23 ± 5% (n = 3) radiochemical yield in 25 min with >99% radiochemical purity and 100 ± 32 GBq/μmol specific activity. 18F-AmBF3-MJ9 was stable in mouse plasma, and was partially (22–30%) internalized after binding to GRPR. Positron emission tomography (PET) imaging and biodistribution studies in mice showed fast renal excretion and good uptake of 18F-AmBF3-MJ9 by GRPR-expressing pancreas and PC-3 prostate cancer xenografts. Tumor uptake was 1.37 ± 0.25%ID/g at 1 h, and 2.20 ± 0.13%ID/g at 2 h post-injection (p.i.) with low background uptake and excellent tumor visualization (tumor-to-muscle ratios of 75.4 ± 5.5). These data suggest that 18F-AmBF3-MJ9 is a promising PET tracer for imaging GRPR-expressing prostate cancers.

Keywords

18F-labeling
AmBF3-MJ9
GRP receptors
Prostate cancer

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Both authors contributed equally.