Assembly and characterization of a cell-particle hybrid system as a potential cancer vaccine Kawther Khalid Ahmed , University of Iowa Follow

[摘要] Cancer vaccines represent a promising treatment modality for a world-wide health problem. Whether as an adjuvant or as a stand-alone therapy, cancer vaccines represent a tumor-specific and systemic treatment potentially capable of eliminating metastatic lesions without the severe side-effects often associated with chemotherapy. Specifically, whole cell tumor vaccines have shown promise in preclinical and clinical settings and the studies presented here represent the beginnings of an approach to improve the antitumor potency of these vaccines. This project demonstrates as "proof of concept" the feasibility of manufacturing tumor cell-particle hybrids. The coupled use of these two components, whole tumor cells and cargo-carrying biodegradable particles, as one entity in a cancer vaccine system is a new line of research. Stable cell-particle hybrids were assembled using avidin-biotin chemistry where cargo-carrying PLGA particles (500 nm diameter) were coated with streptavidin and allowed to bind to tumor cells that had been indirectly labeled with biotin (using an integrin-specific biotinylated antibody). That successful cell-particle hybrids were assembled was determined by multiple means, including flow cytometry, laser scanning confocal microscopy and scanning electron microscopy. Two murine tumor cell lines (representing melanoma and prostate cancer) were investigated in this study and successfully demonstrated the general applicability of the assembly method. Particles appeared to be localized on the cell surface (rather than endocytosed) as determined by microscopic imaging. The cell-particle hybrid was shown to be stable to irradiation, an important consideration since whole tumor cells need to be treated with ionizing radiation prior to being used as vaccines in order to render them nonproliferative and immunogenic. We also characterized loading and release profiles of CpG, a prospective vaccine adjuvant, into PLGA particles. We conclude that we have developed a method for manufacturing cell-particle hybrids comprising PLGA nanoparticles and irradiated tumor cells. The next step would be to use CpG-loaded particles in the assembled hybrid and test the anti-tumor immune efficiency of this cancer vaccine formulation in either a melanoma or prostate cancer model.