Iodinated Choline Transport-Targeted Tracers

We present a novel series of radioiodinated
tracers and potential
theranostics for diseases accompanied by pathological function of
proteins involved in choline transport. Unlike choline analogues labeled
with 11C or 18F that are currently used in the
clinic, the iodinated compounds described herein are applicable in
positron emission tomography, single-photon emission computed tomography,
and potentially in therapy, depending on the iodine isotope selection.
Moreover, favorable half-lives of iodine isotopes result in much less
challenging synthesis by isotope exchange reaction. Six of the described
compounds were nanomolar ligands, and the best compound possessed
an affinity 100-fold greater than that of choline. Biodistribution
data of 125I-labeled ligands in human prostate carcinoma
bearing (PC-3) mice revealed two compounds with a biodistribution
profile superior to that of [18F]­fluorocholine.