Labeling of Anti-HER2 Nanobodies with Astatine-211: Optimization and the Effect of Different Coupling Reagents on Their in Vivo Behavior
| Autor: | Vicky Caveliers, Marleen Keyaerts, Holger Jensen, Emma Aneheim, Yana Dekempeneer, Catarina Xavier, Janik Puttemans, Tom Bäck, Stig Palm, Tony Lahoutte, Sture Lindegren, Matthias D'Huyvetter, Per Albertsson |
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| Přispěvatelé: | Supporting clinical sciences, Medical Imaging, Faculty of Medicine and Pharmacy, Clinical sciences, Nuclear Medicine, Translational Imaging Research Alliance |
| Jazyk: | angličtina |
| Rok vydání: | 2019 |
| Předmět: |
Biodistribution
Immunoconjugates Receptor ErbB-2 Renal cortex medicine.medical_treatment Population Pharmaceutical Science 02 engineering and technology 030226 pharmacology & pharmacy Benzoates 03 medical and health sciences chemistry.chemical_compound Mice 0302 clinical medicine breast cancer In vivo Cell Line Tumor HER2 Drug Discovery medicine Animals Humans Tissue Distribution education Benzamide Ovarian Neoplasms education.field_of_study targeted alpha therapy Trimethyltin Compounds Radiochemistry Single-Domain Antibodies 021001 nanoscience & nanotechnology Alpha Particles Xenograft Model Antitumor Assays In vitro Drug Liberation medicine.anatomical_structure chemistry Reagent Radioimmunotherapy Nanobody Molecular Medicine Female 0210 nano-technology Astatine astatine-211 |
| Popis: | The use of nanobodies (Nbs) as vehicles in targeted alpha therapy (TAT) has gained great interest because of their excellent properties. They combine high in vivo affinity and specificity of binding with fast kinetics. This research investigates a novel targeted therapy that combines the α-particle emitter astatine-211 ( 211At) and the anti-HER2 Nb 2Rs15d to selectively target HER2+ cancer cells. Two distinctive radiochemical methodologies are investigated using three different coupling reagents. The first method uses the coupling reagents, N-succinimidyl 4-(1,2-bis-tert-butoxycarbonyl)guanidinomethyl-3-(trimethylstannyl)benzoate (Boc 2-SGMTB) and N-succinimidyl-3-(trimethylstannyl)benzoate (m-MeATE), which are both directed to amino groups on the Nb, resulting in random conjugation. The second method aims at obtaining a homogeneous tracer population, via a site-specific conjugation of the N-[2-(maleimido)ethyl]-3-(trimethylstannyl)benzamide (MSB) reagent onto the carboxyl-terminalcysteine of the Nb. The resulting radioconjugates are evaluated in vitro and in vivo. 2Rs15d is labeled with 211At using Boc 2-SGMTB, m-MeATE, and MSB. After astatination and purification, the binding specificity of the radioconjugates is validated on HER2+ cells, followed by an in vivo biodistribution assessment in SKOV-3 xenografted mice. α-camera imaging is performed to determine uptake and activity distribution in kidneys/tumors. 2Rs15d astatination resulted in a high radiochemical purity >95% for all radioconjugates. The biodistribution studies of all radioconjugates revealed comparable tumor uptake (higher than 8% ID/g at 1 h). [ 211At]SAGMB-2Rs15d showed minor uptake in normal tissues. Only in the kidneys, a higher uptake was measured after 1 h, but decreased rapidly after 3 h. Astatinated Nbs consisting of m-MeATE or MSB reagents revealed elevated uptake in lungs and stomach, indicating the presence of released 211At. α-Camera imaging of tumors revealed a homogeneous activity distribution. The radioactivity in the kidneys was initially concentrated in the renal cortex, while after 3 h most radioactivity was measured in the medulla, confirming the fast washout into urine. Changing the reagents for Nb astatination resulted in different in vivo biodistribution profiles, while keeping the targeting moiety identical. Boc 2-SGMTB is the preferred reagent for Nb astatination because of its high tumor uptake, its low background signals, and its fast renal excretion. We envision [ 211At]SAGMB-2Rs15d to be a promising therapeutic agent for TAT and aim toward efficacy evaluation. |
| Databáze: | OpenAIRE |
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