Prostate cancer affects over 15% of all men. Prostate cancer, when metastatic, is ultimately incurable. As a result, alternative strategies including immunotherapy are being increasingly investigated. Prostate specific antigen (PSA) is an ideal target antigen for immunotherapy because it has a narrow distribution in tissues and is expressed in virtually all prostate cancers. Gene delivery techniques have the potential to stimulate potent anti-tumor immunity. To date, studies have either focused on non-viral delivery systems such as plasmid DNA-polycation complex co-acervates or viral approaches such as the use of adenoviruses encoding prostate specific antigen. Non-viral plasmid DNA sequences contain CpG motifs. CpG motifs enhance the efficacy of Ad5-PSA vaccines tumor protection. CpG ODN delivered in particulate form is significantly more potent than delivery in solution. Chitosan is a safe natural polymer that complexes with plasmid DNA (with CpG motifs) to form non-viral gene delivery nanoparticles. The objective of this application is to test the hypothesis that co-delivery of chitosan-pcDNA-PSA nanoplexes with AdPSA will enhance tumor protection in a murine model of prostate cancer. This application will test the hypothesis that co-delivery of adenoviruses encoding the prostate specific antigen (AdPSA) with chitosan-pcDNA-PSA nanoplexes will enhance tumor protection in a murine model of prostate cancer. This will be achieved by 1) optimizing chitosan-pcDNA-PSA nanoplexes/adenovirus formulations for gene delivery, 2) characterizing the antigen-specific immune response stimulated from chitosan-pcDNA-PSA nanoplexes/adenovirus formulations and 3) evaluating the combined chitosan- pcDNA-PSA nanoplex/adenovirus formulations for immunotherapeutic protection in a murine prostate cancer model.
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