Publikationsrepositorium - Helmholtz-Zentrum Dresden-Rossendorf

2-[¹⁸F]Fluoro-2-deoxy-D-glucose ([¹⁸F]FDG) as the most important PET radiotracer is available in almost every PET center. However, there are only very few examples using [¹⁸F]FDG as a building block for the synthesis of ¹⁸F-labeled compounds. The present study describes the use of [¹⁸F]FDG as building block for the synthesis of ¹⁸F-labeled peptides and proteins. [¹⁸F]FDG was converted into [¹⁸F]FDG-maleimidehexyloxime ([¹⁸F]FDG-MHO), a novel [¹⁸F]FDG-based prosthetic group for the mild and thiol group-specific ¹⁸F labeling of peptides and proteins. The reaction was performed at 100°C for 15 min in a sealed vial containing [¹⁸F]FDG and N-(6-aminoxy-hexyl)maleimide in 80% ethanol. [¹⁸F]FDG-MHO was obtained in 45-69% radiochemical yield (based upon [¹⁸F]FDG) after HPLC purification in a total synthesis time of 45 min. Chemoselecetive conjugation of [¹⁸F]FDG-MHO to thiol groups was investigated by the reaction with the tripeptide glutathione (GSH) and the single cysteine containing protein annexin A5 (anxA5). Radiolabeled annexin A5 ([¹⁸F]FDG-MHO-anxA5) was obtained in 43-58% radiochemical yield (based upon [¹⁸F]FDG-MHO, n=6), and [¹⁸F]FDG-MHO-anxA5 was used for a pilot small animal PET study to assess in vivo biodistribution and kinetics in a HT-29 murine xenograft model.