Labeling Single Domain Antibody Fragments with Fluorine-18 Using 2,3,5,6-Tetrafluorophenyl 6-[ 18F]Fluoronicotinate Resulting in High Tumor-to-Kidney Ratios
| Autor: | Nick Devoogdt, Darryl McDougald, Michael R. Zalutsky, Ganesan Vaidyanathan, Zhengyuan Zhou |
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| Přispěvatelé: | Supporting clinical sciences, Medical Imaging, Translational Imaging Research Alliance |
| Jazyk: | angličtina |
| Rok vydání: | 2019 |
| Předmět: |
Pharmaceutical Science
02 engineering and technology N-succinimidyl 4-fluorobenzoate 030226 pharmacology & pharmacy 03 medical and health sciences single domain antibody fragment 0302 clinical medicine In vivo HER2 Drug Discovery medicine Her2 receptor Epidermal growth factor receptor Kidney biology Chemistry 021001 nanoscience & nanotechnology Molecular biology In vitro Single-domain antibody medicine.anatomical_structure biology.protein fluorine-18 Molecular Medicine 2 3 5 6-etrafluorophenyl 6-fluoronicotinate 0210 nano-technology Breast carcinoma immunoPET Intracellular |
| Popis: | ImmunoPET agents are being investigated to assess the status of epidermal growth factor receptor 2 (HER2) in breast cancer patients with the goal of selecting those likely to benefit from HER2-targeted therapies and monitoring their progress after these treatments. We have been exploring the use of single domain antibody fragments (sdAbs) labeled with 18F using residualizing prosthetic agents for this purpose. In this study, we have labeled two sdAbs that bind to different domains on the HER2 receptor, 2Rs15d and 5F7, using 2,3,5,6-tetrafluorophenyl 6-[ 18F]fluoronicotinate ([ 18F]TFPFN) and evaluated their HER2 targeting properties in vitro and in vivo. The overall decay-corrected radiochemical yield for the synthesis of [ 18F]TFPFN-2Rs15d and [ 18F]TFPFN-5F7 was 5.7 ± 3.6 and 4.0 ± 2.0%, respectively. The radiochemical purity of labeled sdAbs was >95%, immunoreactive fractions were about 60%, and affinity was in the low nanomolar range. Intracellularly trapped activity from [ 18F]TFPFN-2Rs15d and [ 18F]TFPFN-5F7 in HER2-expressing SKOV-3 ovarian and BT474M1 breast carcinoma cells were similar to the sdAbs labeled using the previously validated radioiodination residualizing prosthetic agents N-succinimidyl 4-guanidinomethyl-3-[ 125I]iodobenzoate ([ 125I]SGMIB) and N-succinimidyl 3-guanidinomethyl-5-[ 125I]iodobenzoate (iso-[ 125I]SGMIB). Intracellular activity was about 2-fold higher for radiolabeled 5F7 compared with 2Rs15d for both 18F and 125I. While tumor uptake of both [ 18F]TFPFN-2Rs15d and [ 18F]TFPFN-5F7 was comparable to those for the coadministered 125I-labeled sdAb, renal uptake of the 18F-labeled sdAbs was substantially lower. In microPET images, the tumor was clearly delineated in SKOV-3 and BT474 xenograft-bearing athymic mice with low levels of background activity in normal tissues, except the bladder. These results indicate that the [ 18F]TFPFN prosthetic group could be a valuable reagent for developing sdAb-based immunoPET imaging agents. |
| Databáze: | OpenAIRE |
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