Synthesis and Characterization of 18F-Interleukin-8 Using a Cell-Free Translation System and 4-18F-Fluoro-l-Proline
| Autor: | Kiichi Ishiwata, Katsuhiko Shibuya, Ryuichi Harada, Takeo Yoshikawa, Yoichi Ishikawa, Kazuhiko Yanai, Nobuyuki Okamura, Shozo Furumoto, Ren Iwata |
|---|---|
| Rok vydání: | 2016 |
| Předmět: |
0301 basic medicine
chemistry.chemical_classification Cell-free protein synthesis In vitro 030218 nuclear medicine & medical imaging Amino acid Cell-free system 03 medical and health sciences 030104 developmental biology 0302 clinical medicine chemistry Biochemistry In vivo Radiology Nuclear Medicine and imaging Molecular imaging Receptor Peptide sequence |
| Zdroj: | Journal of Nuclear Medicine. 57:634-639 |
| ISSN: | 2159-662X 0161-5505 |
| DOI: | 10.2967/jnumed.115.162602 |
| Popis: | Macromolecules such as proteins are attracting increasing interest for molecular imaging. We previously proposed a novel strategy for preparing macromolecules labeled with a PET radionuclide, 11C, using a cell-free translation system with 11C-methionine. However, macromolecules tend to exhibit slower kinetics, thus requiring a longer scanning time. Here, we expand our strategy using 18F, which has a longer half-life, with the cell-free translation system with 4-18F-fluoro-l-proline (18F-FPro). We evaluated 18F-interleukin-8 (18F-IL-8) produced by this method in vitro and in vivo to provide a proof of concept of our strategy. Methods: We tested some fluorinated amino acids to be incorporated into a protein. Trans-18F-FPro was radiolabeled from the corresponding precursor. 18F-IL-8 was produced using the cell-free translation system with trans-18F-FPro instead of natural l-proline with incubation at 37°C for 120 min. An in vitro binding assay of 18F-IL-8 was performed using IL-8 receptor–expressing cells. After intravenous administration of 18F-IL-8, in vivo PET imaging of IL-8 receptor–expressing xenograft-bearing mice was performed using a small-animal PET system. Results: FPro was identified as an amino acid incorporated into the protein. 18F-IL-8 was successfully prepared using the cell-free translation system and trans-18F-FPro with the radiochemical yield of 1.5% (decay-corrected) based on trans-18F-FPro. In vitro binding assays of 18F-IL-8 demonstrated its binding to IL-8 receptor. In vivo PET imaging demonstrated that 18F-IL-8 clearly accumulated in IL-8 receptor–expressing xenografts in mice, unlike trans-18F-FPro. Conclusion:18F-IL-8 produced by this method binds to IL-8 receptors in vitro, and 18F-IL-8 PET clearly visualizes its target receptor–expressing xenograft in vivo. Therefore, this technique might be useful for labeling macromolecules and performing preclinical evaluations of proteins of interest in vitro and in vivo. |
| Databáze: | OpenAIRE |
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