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Updated: Oct 11, 2025
MR Molecular Imaging of Prostate Cancer with a Small Molecular CLT1 Peptide Targeted Contrast Agent
Published on: September 3, 2013
Application Analysis of 124I-PPMN for Enhanced Retention in Tumors of Prostate Cancer Xenograft Mice
Lei Xia1, Li Wen1,2, Xiangxi Meng1
1Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education/Beijing), NMPA Key Laboratory for Research and Evaluation of Radiopharmaceuticals (National Medical Products Administration), Department of Nuclear Medicine, Peking University Cancer Hospital & Institute, Beijing, 100142, People's Republic of China.
Background:
In recent years, nuclear medicine imaging and therapy for prostate cancer have radically changed through the introduction of radiolabeled prostate-specific membrane antigen (PSMA)-binding peptides. However, these small molecular probes have some inherent limitations, including high nephrotoxicity and short circulation time, which limits their utility in biological systems.
Methods And Results:
In this study, organic melanin nanoparticles were used to directly label the long half-life radionuclide 124I (t1/2=100.8 h), and PSMA small molecular groups were efficiently bonded on the surface of nanoparticles to construct the PSMA-targeted long-retention nanoprobe 124I-PPMN, which has the potential to increase tumor uptake and prolong residence time. The results showed that the nanoprobe could substantially aggregate in the tumors of prostate cancer xenograft mice and was visible for more than 72 h. Positron Emission Computed Tomography (PET) imaging showed that the nanoprobe could be used for precise imaging of prostate cancer with high expression of PSMA. In addition, organic melanin nanoparticles labeled with an elemental radionuclide achieved a stable, metal-free structure. Cell experiments and mouse toxicity experiments indicated that the nanoprobe has high safety.
Conclusion:
The new nanoprobe constructed in this study has high specificity and biocompatibility. In the future, combined with the multifunctional potential of melanin nanoparticles, this nanoprobe is expected to be used in the integrated theranostics of prostate cancer.
Insights
Researchers developed a new melanin nanoparticle nanoprobe for prostate cancer imaging. This targeted probe shows high tumor accumulation and retention, offering a safer and more effective diagnostic tool.
Area of Science:
- Nuclear Medicine
- Nanotechnology
- Oncology
Background:
- Prostate cancer management has advanced with PSMA-binding peptides for imaging and therapy.
- Limitations of current PSMA probes include nephrotoxicity and short circulation times.
Purpose of the Study:
- To develop a novel PSMA-targeted nanoprobe with improved tumor uptake and retention for prostate cancer.
- To overcome the limitations of small molecular PSMA probes.
Main Methods:
- Organic melanin nanoparticles were labeled with Iodine-124 (124I).
- Prostate-specific membrane antigen (PSMA) targeting groups were conjugated to the nanoparticle surface, creating the 124I-PPMN nanoprobe.
- In vivo and in vitro studies were conducted using prostate cancer xenograft models.
Main Results:
- The 124I-PPMN nanoprobe demonstrated significant aggregation and prolonged retention (>72 h) in prostate cancer tumors.
- Positron Emission Tomography (PET) imaging confirmed precise visualization of PSMA-expressing prostate tumors.
- The nanoprobe exhibited a stable, metal-free structure and high safety in toxicity assessments.
Conclusions:
- The developed nanoprobe exhibits high specificity and biocompatibility for prostate cancer imaging.
- Melanin nanoparticles offer multifunctional potential for future integrated theranostics.
- This novel nanoprobe represents a promising advancement in prostate cancer diagnostics.
