Preclinical Evaluation of a Fibroblast Activation Protein and a Prostate-Specific Membrane Antigen Dual-Targeted Probe for Noninvasive Prostate Cancer Imaging

Prostate-specific membrane antigen (PSMA) is a prostate cancer target that plays a crucial role in prostate cancer diagnosis and therapy. Herein, a novel dual-targeted imaging probe, [68Ga]Ga-FAPI-PSMA, was prepared by radiolabeling conjugated DOTA-FAPI-PSMA with the short half-life radionuclide gallium-68 (68Ga), which is dedicated to prostate cancer diagnostic imaging. In vitro, [68Ga]Ga-FAPI-PSMA had higher affinity for the PSMA and FAP high-expressing cell lines 22Rv1 and U87 MG with IC50 values of 4.73 and 2.10 nM, respectively, than in the corresponding negative expression cell lines PC3 and A549, and significant differences in cell uptake were also observed. In vivo, [68Ga]Ga-FAPI-PSMA was rapidly cleared from the body, and the estimated radiation dose was relatively low compared with several other FAPI probes. In 22Rv1 and U87 MG tumor xenografts, [68Ga]Ga-FAPI-PSMA rapidly accumulated in tumors after administration, and the best images can be obtained at 1 h postinjection. In conclusion, the dual-targeted probe [68Ga]Ga-FAPI-PSMA was successfully prepared for in vivo prostate cancer PET/CT imaging.