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- El Fakiri, Mohamed, et al.
(författare)
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Development and Preclinical Evaluation of [211At]PSAt-3-Ga: An Inhibitor for Targeted a-Therapy of Prostate Cancer
- 2024
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Ingår i: JOURNAL OF NUCLEAR MEDICINE. - 0161-5505 .- 1535-5667. ; 65:4, s. 593-599
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Tidskriftsartikel (refereegranskat)abstract
- The application of prostate -specific membrane antigen (PSMA)- targeted a -therapy is a promising alternative to b 2 -particle-based treatments. 211 At is among the potential a -emitters that are favorable for this concept. Herein, 211 At-based PSMA radiopharmaceuticals were designed, developed, and evaluated. Methods: To identify a 211 At-labeled lead, a surrogate strategy was applied. Because astatine does not exist as a stable nuclide, it is commonly replaced with iodine to mimic the pharmacokinetic behavior of the corresponding 211 At-labeled compounds. To facilitate the process of structural design, iodine -based candidates were radiolabeled with the PET radionuclide 68 Ga to study their preliminary in vitro and in vivo properties before the desired 211 At-labeled lead compound was formed. The most promising candidate from this evaluation was chosen to be 211 At-labeled and tested in biodistribution studies. Results: All 68 Ga-labeled surrogates displayed affinities in the nanomolar range and specific internalization in PSMA-positive LNCaP cells. PET imaging of these compounds identified [ 68 Ga]PSGa- 3 as the lead compound. Subsequently, [ 211 At]PSAt- 3 -Ga was synthesized in a radiochemical yield of 35% and showed tumor uptake of 19 +/- 8 percentage injected dose per gram of tissue (%ID/g) at 1 h after injection and 7.6 +/- 2.9 %ID/g after 24 h. Uptake in off -target tissues such as the thyroid (2.0 +/- 1.1 %ID/g), spleen (3.0 +/- 0.6 %ID/g), or stomach (2.0 +/- 0.4 %ID/g) was low, indicating low in vivo deastatination of [ 211 At]PSAt- 3 -Ga. Conclusion: The reported findings support the use of iodine -based and 68 Ga-labeled variants as a convenient strategy for developing astatinated compounds and confirm [ 211 At]PSAt- 3 as a promising radiopharmaceutical for targeted a -therapy.
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