Iodinated Copper-Cysteamine Nanoparticles as Radiosensitizers for Tumor Radiotherapy

Area of Science:

• Nanomedicine
• Radiotherapy
• Cancer Research

Background:

• Radiotherapy is a primary cancer treatment.
• Copper-cysteamine (Cu-Cy) nanoparticles show promise as X-ray-induced photodynamic therapy agents.
• Iodide, a high-Z element, enhances X-ray absorption and includes the beta-decay nuclide ¹³¹I.

Purpose of the Study:

• Investigate the X-ray-induced photodynamic therapy potential of iodinated Cu-Cy (Cu-Cy-I) nanoparticles.
• Explore the local treatment efficacy of ¹³¹I-labeled Cu-Cy-I ([¹³¹I]Cu-Cy-I) nanoparticles.

Main Methods:

• Synthesized [¹³¹I]Cu-Cy-I nanoparticles using [¹³¹I]I^- anions.
• Assessed in vitro radiobiological effects of Cu-Cy-I nanoparticles with X-ray irradiation on tumor cells.
• Evaluated in vivo tumor growth inhibition in 4T1 tumor-xenografted mice using Cu-Cy-I nanoparticles combined with X-ray radiotherapy and [¹³¹I]Cu-Cy-I nanoparticles.

Main Results:

• Cu-Cy-I nanoparticles with X-ray irradiation increased intracellular reactive oxygen species (ROS) and DNA damage in 4T1 cells, enhancing tumor cell killing.
• Combination therapy of intratumoral Cu-Cy-I injection and X-ray radiotherapy improved tumor growth inhibition and prolonged survival in mice with 4T1 breast carcinoma.
• The efficacy of [¹³¹I]Cu-Cy-I nanoparticles for local treatment at a low ¹³¹I dose was not verified.

Conclusions:

• Cu-Cy-I nanoparticles show potential as radiosensitizers to improve external X-ray radiotherapy efficacy.
• Further research is needed to optimize nanoparticle size for investigating the radiotherapy potential of [¹³¹I]Cu-Cy-I nanoparticles.