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  2. Preclinical evaluation of [13xLa]La-FAP-2286 as a novel theranostic agent for tumors expressing fibroblast activation protein

Preclinical evaluation of [13xLa]La-FAP-2286 as a novel theranostic agent for tumors expressing fibroblast activation protein

  • Sci Rep. 2025 Mar 3;15(1):7475. doi: 10.1038/s41598-025-91716-3.
Ali Shirpour 1 Asghar Hadadi 1 Samaneh Zolghadri 2 Sara Vosoughi 3 Saeed Rajabifar 3
Affiliations

Affiliations

  • 1 Department of Medical Radiation Engineering, Science and Research Branch, Islamic Azad University, Tehran, Iran.
  • 2 Radiation Application Research School, Nuclear Science and Technology Research Institute (NSTRI), Tehran, 14155-1339, Iran. szolghadri@aeoi.org.ir.
  • 3 Radiation Application Research School, Nuclear Science and Technology Research Institute (NSTRI), Tehran, 14155-1339, Iran.
Abstract

In this study, a novel theranostic radiopharmaceutical, [13xLa]La-FAP-2286, for targeting Fibroblast Activation Protein (FAP)-positive tumors. The theranostic pair of 132La (half-life: 4.59 h, 42.1% β⁺) and 135La (half-life: 18.91 h, 100% EC) was produced via proton bombardment of natural barium in a 30 MeV cyclotron, achieving high radionuclidic purity (99.9%) and radiochemical purity (RCP > 99%). Stability tests revealed the RCP greater than 91% over 24 h in human serum and PBS buffer. Cellular studies confirmed high binding affinity (KD = 0.51 ± 0.12 nM) and effective internalization of [13xLa]La-FAP-2286 in FAP + tumor cells. Distribution coefficient (log D) measurements demonstrated high hydrophilicity of the complex with a value of - 3.21 ± 0.14. Imaging and biodistribution studies in tumor-bearing mice further confirmed tumor targeting, with significant uptake observed up to 48 h post-injection. These results suggest [13xLa]La-FAP-2286 can be considered a candidate for theranostic applications, offering both practical PET imaging and targeted Auger-electron therapy for Cancer treatment.

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