Evaluation of Immunogene Therapy Using a Plasmid Encoding IL-15 Delivered by Electroporation in a 3D Tumor Model and a Mouse Melanoma Model

Melanoma is an aggressive disease with few effective treatment options. Non-toxic, anti-tumor therapies and prophylactic approaches are currently being investigated to identify treatment options that will control and remove late-stage melanoma.;The overall goal of this project was to establish an effective delivery method for a plasmid encoding human interleukin phIL--15 into mouse melanoma cells B16.F10 using the gene transfer technique electroporation EP. The EP delivery phIL--15 was optimized using an in vitro 3D tumor model. The purpose was to translate these IL--15 delivery conditions into an in vivo mouse melanoma model to study IL--15 signal transduction and stimulate immune cells to destroy tumor antigens as well as promote an anti-tumor immune memory response.;The in vitro 3D tumor model and the mouse model demonstrated similar expression patterns when delivering phIL--15 with different EP conditions. Intra-tumoral delivery using 500V per cm 20ms enhanced gene delivery and increased IL--15 protein expression compared to 1300V per cm 100micros. There was also a visible increase in transfection efficacy between tumor cells compared to skin cells when delivering pmIL--12 and phIL -- 15 plasmid constructs in vivo. The plasmid and EP groups 1300 V per cm and 500V per cm stimulated increased expression of cytokines IL--1 beta, IL--6, INFgamma, MIP-1 beta and TNF alpha. These EP groups also promoted tumor regression by up-regulating CD8 T cells and CD4 T cells which targeted melanoma. Regression and survival studies demonstrated that 73.3 percent of mice cleared B16.F10 cells when treated with phIL--15 1300V per cm and pVax 500V per cm. In addition, 53 percent of the mice responded to the phIL--15 500V/cm treatment group. Furthermore, 75 percent of the mice from group phIL--15 500V per cm survived secondary inoculation and tumor challenge. In conclusion, plasmid with encoding gene insert phIL--15 delivered by EP has the potential to act as an anti-tumor therapy because it promotes melanoma regression and enhances mouse survival through innate and adaptive cell-mediated immune responses.