Two Novel PET Radiopharmaceuticals for Endothelial Vascular Cell Adhesion Molecule-1 (VCAM-1) Targeting

• Main Authors: Sara Pastorino, Sara Baldassari, Giorgia Ailuno, Guendalina Zuccari, Giuliana Drava, Andrea Petretto, Vanessa Cossu, Cecilia Marini, Silvana Alfei, Tullio Florio, Gianmario Sambuceti, Gabriele Caviglioli
• Format: Article
• Language: English
• Published: MDPI AG 2021-07-01
• Series: Pharmaceutics
• Subjects: radiopharmaceuticals; VCAM-1; pretargeting; imaging; PET; Gallium-68
• Online Access: https://www.mdpi.com/1999-4923/13/7/1025

Atherosclerosis is a chronic progressive disease involving inflammatory events, such as the overexpression of adhesion molecules including the endothelial Vascular Cell Adhesion Molecule-1 (VCAM-1). VCAM-1 is rapidly overexpressed in the first stages of atherosclerosis, thus representing a promising target for early atheroma detection. Two novel Positron Emission Tomography (PET) radiopharmaceuticals (MacroP and NAMP), based on the VCAM-1-binding peptide having sequence VHPKQHRGGSKGC, were synthesized and characterized. MacroP is derived from the direct conjugation of a DOTA derivative with the peptide, while NAMP is a biotin derivative conceived to be employed in a three-step pretargeting system, involving the use of a double-chelating derivative of DOTA. The identity of the newly synthesized radiopharmaceuticals was confirmed by mass spectrometry and, after radiolabeling with ⁶⁸Ga, both showed high radiochemical purity; in vitro tests on human umbilical vein endothelial cells evidenced their VCAM-1 binding ability, with higher radioactive uptake in the case of NAMP. Moreover, NAMP might also be employed in a theranostic approach in association with functionalized biotinylated nanoparticles.