A Cyanine-Bridged Somatostatin Hybrid Probe for Multimodal SSTR2 Imaging in Vitro and in Vivo: Synthesis and Evaluation |
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Authors: | Isabelle Heing-Becker Dr Carsten Grötzinger Dr Nicola Beindorff Dr Sonal Prasad Dr Sarah Erdmann Dr Samantha Exner Prof?Dr Rainer Haag Dr Kai Licha |
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Affiliation: | 1. Institut für Chemie und Biochemie, Freie Universität Berlin, Takustr. 3, 14195 Berlin, Germany;2. Department of Hepatology and Gastroenterology, Charité – Universitätsmedizin Berlin, Augustenburger Platz?1, 13353 Berlin, Germany;3. BERIC – Berlin Experimental Radionuclide Imaging Center, Charité – Universitätsmedizin Berlin, Augustenburger Platz?1, 13353 Berlin, Germany;4. BERIC – Berlin Experimental Radionuclide Imaging Center, Charité – Universitätsmedizin Berlin, Augustenburger Platz?1, 13353 Berlin, Germany
Department of Nuclear Medicine, Charité – Universitätsmedizin Berlin, Augustenburger Platz?1, 13353 Berlin, Germany |
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Abstract: | Multimodal imaging probes have attracted the interest of ongoing research, for example, for the surgical removal of tumors. Modular synthesis approaches allow the construction of hybrid probes consisting of a radiotracer, a fluorophore and a targeting unit. We present the synthesis of a new asymmetric bifunctional cyanine dye that can be used as a structural and functional linker for the construction of such hybrid probes. 68Ga-DOTATATE, a well-characterized radiopeptide targeting the overexpressed somatostatin receptor subtype 2 (SSTR2) in neuroendocrine tumors, was labeled with our cyanine dye, thus providing additional information along with the data obtained from the radiotracer. We tested the SSTR2-targeting and imaging properties of the resulting probe 68Ga-DOTA-ICC-TATE in vitro and in a tumor xenograft mouse model. Despite the close proximity between dye and pharmacophore, we observed a high binding affinity towards SSTR2 as well as elevated uptake in SSTR2-overexpressing tumors in the positron emission tomography (PET) scan and histological examination. |
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Keywords: | cyanines fluorescence multimodal imaging octreotate SSTR2 |
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