PT  - JOURNAL ARTICLE
AU  - Liu, Wenge
AU  - McDaniel, Jonathan
AU  - Li, Xinghai
AU  - Asai, Daisuke
AU  - Quiroz, Felipe Garcia
AU  - Schaal, Jeffery
AU  - Park, Ji Sun
AU  - Zalutsky, Michael
AU  - Chilkoti, Ashutosh
TI  - Brachytherapy Using Injectable Seeds That Are Self-Assembled from Genetically Encoded Polypeptides <em>In Situ</em>
AID  - 10.1158/0008-5472.CAN-12-2127
DP  - 2012 Nov 15
TA  - Cancer Research
PG  - 5956--5965
VI  - 72
IP  - 22
4099  - http://cancerres.aacrjournals.org/content/72/22/5956.short
4100  - http://cancerres.aacrjournals.org/content/72/22/5956.full
SO  - Cancer Res2012 Nov 15; 72
AB  - Brachytherapy is a common clinical technique involving implantation of sealed radioactive “seeds” within a tumor to selectively irradiate the tumor mass while minimizing systemic toxicity. To mitigate the disadvantages associated with complex surgical implantation and subsequent device removal procedures, we have developed an alternative approach using a genetically encoded peptide polymer solution composed of a thermally responsive elastin-like polypeptide (ELP) radiolabeled with 131I that self-assembles into radionuclide seeds upon intratumoral injection. The formation of these nontoxic and biodegradable polymer seeds led to prolonged intratumoral retention (∼85% ID/tumor 7 days postinjection) of the radionuclide, elicited a tumor growth delay in 100% of the tumors in two human xenografts (FaDu and PC-3), and cured more than 67% of tumor-bearing animals after a single administration of labeled ELP. These results suggest that in situ self-assembly of biodegradable and injectable radionuclide-containing polypeptide seeds could be a promising therapeutic alternative to conventional brachytherapy. Cancer Res; 72(22); 5956–65. ©2012 AACR.