Preloading with L-BPA, L-tyrosine and L-DOPA enhances the uptake of [F]FBPA in human and mouse tumour cell lines.

Aim of this study was to investigate if cellular [F]FBPA uptake can be increased upon preloading with amino acids. [F]FBPA uptake was assessed in HuH-7, CaCo-2 and B16-F1 cells pretreated with different concentrations or incubation times of L-BPA, L-tyrosine or L-DOPA. Without preloading, highest uptake of [F]FBPA was observed in B16-F1 cells, followed by CaCo-2 cells and HuH-7 cells.

Synthesis and preclinical characterization of 1-(6'-deoxy-6'-[F]fluoro-β-d-allofuranosyl)-2-nitroimidazole (β-6'-[F]FAZAL) as a positron emission tomography radiotracer to assess tumor hypoxia.

Positron emission tomography (PET) using fluorine-18 (F)-labeled 2-nitroimidazole radiotracers has proven useful for assessment of tumor oxygenation. However, the passive diffusion-driven cellular uptake of currently available radiotracers results in slow kinetics and low tumor-to-background ratios. With the aim to develop a compound that is actively transported into cells, 1-(6'-deoxy-6'-[F]fluoro-β-d-allofuranosyl)-2-nitroimidazole (β-[F]1), a putative nucleoside transporter substrate, was synthetized by nucleophilic [F]fluoride substitution of an acetyl protected labeling precursor with a tosylate leaving group (β-6) in a final radiochemical yield of 12±8% (n=10, based on [F]fluoride starting activity) in a total synthesis time of 60min with a specific activity at end of synthesis of 218±58GBq/μmol (n=10).