Feasibility study for the use of gene electrotransfer and cell electrofusion as a single-step technique for the generation of activated cancer cell vaccines

Abstract In the search for safe induction of cellular and humoral cancer immunity dendritic cell-based therapies hold great potential. This approach is based on manipulation of dendritic cells to activate immune system against specific cancer antigens. For the development of an effective cell vaccine platform, gene transfer, and cell fusion have been used for modification of dendritic or tumor cells to express immune (co)stimulatory signals and to load dendritic cells with tumor antigens. Both, gene transfer and cell fusion can be achieved by single technique, a cell membrane electroporation. The cell membrane exposed to external electric field becomes temporarily permeable, enabling introduction of genetic material, and also fusogenic, enabling the fusion of cells in the close contact. We tested the feasibility of combining gene electrotransfer and electrofusion into a single-step technique. We evaluated the effects of electroporation buffer, pulse parameters, and cell membrane fluidity on the efficacy of the combined method. We determined the percentage of fused cells expressing green fluorescence protein GFP in a murine cell model of melanoma B16F1, an often-used cell line in pre-clinical studies. Our results suggest that gene electrotransfer and cell electrofusion can be applied in a single procedure. The percentage of viable hybrid cells expressing GFP depends on electric pulse parameters and the composition of the electroporation buffer. Cell membrane fluidity cannot be related to the efficiency of this technique. Further optimization of electric pulse parameters and buffers has to be accomplished before this technique can be used for preparation of effective dendritic cell-based vaccines.