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Fast enzymatic synthesis of n.c.a. 6‐[ 18 F]fluorodopamine (FDA) from n.c.a. 6‐[ 18 F]FDOPA and the fate of 6‐FDOPA and 6‐FDA in neuroblastoma and Caki‐1 cells after their uptake
Author(s) -
Kuçi Zyrafete,
Ehrlichmann Walter,
Sauer Jörg,
Handgretinger Rupert,
Bruchelt Gernot,
Reischl Gerald
Publication year - 2019
Publication title -
journal of labelled compounds and radiopharmaceuticals
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.432
H-Index - 47
eISSN - 1099-1344
pISSN - 0362-4803
DOI - 10.1002/jlcr.3752
Subject(s) - chemistry , dopamine transporter , neuroblastoma , enzyme , transporter , radiochemistry , nuclear medicine , cell culture , biochemistry , medicine , biology , genetics , gene
The catecholamine analogue [ 123 I] m IBG has been used for scintigraphic imaging of neuroblastoma since 1984. It is taken up by the noradrenaline transporter (NAT), which is present in most neuroblastoma cells. An alternative imaging method could be PET with 6‐[ 18 F]fluorodopamine, which is also taken up by NAT, but—in contrast to m IBG—also by dopamine transporter (DAT), present in neuroblastoma cells (NAT > DAT). An enzymatic method was established allowing a rapid, quantitative transformation of FDOPA to FDA by DOPA decarboxylase within 25 minutes. This strategy was applied to [ 18 F]FDOPA, which was produced via nucleophilic synthesis (RCY 15%, 10 GBq, 50 GBq/μmol) and subsequently converted to [ 18 F]FDA (RCY 35%‐50%, n = 5). Uptake and metabolism of FDOPA and FDA were analyzed in human Kelly and SK‐N‐SH neuroblastoma cell lines and in human Caki‐1 kidney cells that can take up catecholamines and m IBG via an organic cation transporter (OCT). FDOPA and FDA were taken up by all three cells, but FDOPA could only be converted to FDA in neuroblastoma cells. As today, [ 18 F]FDOPA is well available in high yields, efficient enzymatic conversion to [ 18 F]FDA to be used for NAT/DAT PET imaging in neuroendocrine tumors is an attractive, alternative synthesis route.