The overall goal of this proposal is to develop a novel local drug delivery system for cancer radiotherapy by direct intratumoral administration of a thermally sensitive macromolecule conjugated to a therapeutic radionuclide of interest. Thermally sensitive elastin-like polypeptides (ELPs) that spontaneously undergo a soluble-insoluble phase transition between room temperature and body temperature leading to the formation of a coacervate, """"""""gel-like"""""""" phase will be designed and optimized at the molecular level via genetic engineering methods. Two innovative strategies to increase the retention of the ELPs in solid tumors beyond that provided by thermal coacervation will also be investigated: (1) Zn-mediated reversible crosslinking of ELP coacervates, and (2) binding of ELPs and their proteolytic fragments to extracellular matrix proteins. These genetically engineered ELPs will be conjugated to 131I, a therapeutic radioisotope, and infused into a tumor to spontaneously form a radioactive depot within the tumor with long in vivo retention (>1 week) at the injection site. These polymers will be evaluated for therapeutic efficacy and immunogenic properties. We hypothesize that this local delivery approach for the targeted irradiation of solid tumors from the """"""""inside-out"""""""" will enhance therapeutic efficacy by providing enhanced exposure of the radionuclide to the tumor while minimizing exposure of healthy tissues, thereby reducing systemic toxicity. Furthermore, the clinical significance of the proposed research is that it will lead to a novel, genetically engineered, nonimmunogenic injectable radionuclide deposition system that is an improvement over current brachytherapy methods.

National Institute of Health (NIH)
National Cancer Institute (NCI)
Research Project (R01)
Project #
Application #
Study Section
Gene and Drug Delivery Systems Study Section (GDD)
Program Officer
Prasanna, Pat G
Project Start
Project End
Budget Start
Budget End
Support Year
Fiscal Year
Total Cost
Indirect Cost
Duke University
Biomedical Engineering
Biomed Engr/Col Engr/Engr Sta
United States
Zip Code
Schaal, Jeffrey L; Li, Xinghai; Mastria, Eric et al. (2016) Injectable polypeptide micelles that form radiation crosslinked hydrogels in situ for intratumoral radiotherapy. J Control Release 228:58-66
Mukerji, Ratul; Schaal, Jeffrey; Li, Xinghai et al. (2016) Spatiotemporally photoradiation-controlled intratumoral depot for combination of brachytherapy and photodynamic therapy for solid tumor. Biomaterials 79:79-87
Asai, Daisuke; Xu, Donghua; Liu, Wenge et al. (2012) Protein polymer hydrogels by in situ, rapid and reversible self-gelation. Biomaterials 33:5451-8
Liu, Wenge; McDaniel, Jonathan; Li, Xinghai et al. (2012) Brachytherapy using injectable seeds that are self-assembled from genetically encoded polypeptides in situ. Cancer Res 72:5956-65
Liu, Wenge; MacKay, J Andrew; Dreher, Matthew R et al. (2010) Injectable intratumoral depot of thermally responsive polypeptide-radionuclide conjugates delays tumor progression in a mouse model. J Control Release 144:2-9