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Published on: December 20, 2024
A two-step strategy to radiolabel choline phospholipids with 99mTc in S180 cell membranes via strain-promoted
1Beijing National Laboratory for Molecular Sciences, Radiochemistry and Radiation Chemistry Key Laboratory of Fundamental Science, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China.
Abstract:
As tumor markers, the radiolabeling of choline (Cho)-containing phospholipids in cellular membranes with 99mTc is a challenge. The conventional strategy to combine the metallic radionuclide with Cho by large ligand damages the bioactivity of Cho, resulting in low tumor-to-nontumor ratios. Pretargeting strategy based on strain-promoted cyclooctyne-azide cycloaddition (SPAAC) reaction was applied to solve this general problem. Functional click synthons were synthesized as pretargeting components: azidoethyl-choline (AECho) serves as tumor marker and azadibenzocyclooctyne (ADIBO) conjugated to bis(2-pieolyl) amine (BPA) ligand (ADIBO-BPA) as 99mTc(CO)3-labeling and azido-binding group. Both in vitro cell experiment and in vivo biodistribution experiment indicate that it is versatile to radiolabel Cho in cellular membranes via this two-step pretargeting strategy. We believe that this pretargeting strategy can indeed enhance the target-specificity and also reduce background signals to optimize imaging quality.

