Zusammenfassung: | |
Abstract: The glucagon receptor (GCGR) is emerging as an important target in anti-diabetic therapy, especially as part of the pharmacology of dual glucagon-like peptide-1/glucagon (GLP-1/GCG) receptor agonists. However, currently, there are no suitable biomarkers that reliably demonstrate GCG receptor target engagement. Methods: Two potent GCG receptor peptide agonists, S01-GCG and S02-GCG, were labeled with positron emission tomography (PET) radionuclide gallium-68. The GCG receptor binding affinity and specificity of the resulting radiopharmaceuticals [ 68 Ga]Ga-DO3A-S01-GCG and [ 68 Ga]Ga-DO3A-S02-GCG were evaluated in HEK-293 cells overexpressing the human GCG receptor and on frozen hepatic sections from human, non-human primate, and rat. In in vivo biodistribution, binding specificity and dosimetry were assessed in rat. Results: [ 68 Ga]Ga-DO3A-S01-GCG in particular demonstrated GCG receptor-mediated binding in cells and liver tissue with affinity in the nanomolar range required for imaging. [ 68 Ga]Ga-DO3A-S01-GCG binding was not blocked by co-incubation of a GLP-1 agonist. In vivo binding in rat liver was GCG receptor specific with low non-specific binding throughout the body. Moreover, the extrapolated human effective doses, predicted from rat biodistribution data, allow for repeated PET imaging potentially also in combination with GLP-1R radiopharmaceuticals. Conclusion: [ 68 Ga]Ga-DO3A-S01-GCG thus constitutes a first-in-class PET tracer targeting the GCG receptor, with suitable properties for clinical development. This tool has potential to provide direct quantitative evidence of GCG receptor occupancy in humans.
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Lizenzbestimmungen: | CC BY 4.0 Unported - https://creativecommons.org/licenses/by/4.0/ |
Publikationstyp: | Article |
Publikationsstatus: | publishedVersion |
Erstveröffentlichung: | 2019 |
Schlagwörter (englisch): | Dual agonist, GCG, GLP-1 receptor, Glucagon, Type 2 diabetes, antidiabetic agent, cysteine, exendin 4, Ga DO3A S01 GCG, Ga DO3A S02 GCG, gadoteridol, gallium 68, glucagon like peptide 1, glucagon like peptide 1 receptor agonist, glucagon receptor, glucagon receptor agonist, peptide, phosphorus, radioisotope, radiopharmaceutical agent, tracer, unclassified drug, adult, animal model, autoradiography, binding affinity, body weight, body weight loss, cAMP assay, carboxy terminal sequence, controlled study, dosimetry, effective dose (radiation), female, gene overexpression, HEK293 cell line, high performance liquid chromatography, human, human cell, human tissue, internalization, isotope labeling, liver biopsy, liver tissue, male, nonhuman, positron emission tomography, priority journal, quality control, radioactivity, radiochemistry, rat, receptor affinity, receptor occupancy, retention time |
Fachliche Zuordnung (DDC): | 610 | Medizin, Gesundheit |
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