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Brachytherapy using injectable seeds that are self-assembled from genetically encoded polypeptides in situ
Wenge Liu1, Jonathan McDaniel, Xinghai Li
1Department of Biomedical Engineering, Duke University, Durham, North Carolina, USA. wengeliu@duke.edu
Cancer Research
|November 17, 2012
Summary
Researchers developed injectable polypeptide seeds for brachytherapy, offering a promising alternative to conventional methods. These self-assembling seeds provide prolonged radionuclide retention and significant tumor reduction in preclinical models.
Area of Science:
- Biomedical Engineering
- Oncology
- Radiochemistry
Background:
- Brachytherapy uses implanted radioactive seeds for localized tumor irradiation.
- Conventional brachytherapy involves complex surgical procedures for seed implantation and removal.
- Minimizing systemic toxicity and procedural complexity are key challenges in brachytherapy.
Purpose of the Study:
- To develop an alternative to conventional brachytherapy using self-assembling, injectable radionuclide seeds.
- To create a biodegradable polymer system for targeted radionuclide delivery within tumors.
- To evaluate the efficacy and safety of radiolabeled elastin-like polypeptides (ELPs) for cancer treatment.
Main Methods:
- Genetically engineered elastin-like polypeptides (ELPs) were radiolabeled with iodine-131 ((131)I).
- The radiolabeled ELP solution was injected intratumorally, where it self-assembled into polymer seeds.
- Tumor retention of the radionuclide, tumor growth delay, and survival rates were assessed in human xenograft models (FaDu and PC-3).
Main Results:
- Intratumoral injection of (131)I-labeled ELP resulted in in situ formation of radionuclide-containing polymer seeds.
- The polymer seeds demonstrated prolonged intratumoral retention of the radionuclide (~85% ID/tumor at 7 days).
- A single administration of labeled ELP induced a tumor growth delay in 100% of treated xenografts and achieved a cure rate of over 67%.
Conclusions:
- In situ self-assembly of biodegradable, injectable polypeptide seeds offers a novel therapeutic approach.
- This method presents a promising alternative to conventional brachytherapy, potentially reducing invasiveness and toxicity.
- The developed ELP-based system shows significant potential for effective localized cancer treatment.
