Development of polymer plasmid DNA gene delivery

Cancer gene therapy as a treatment for brain cancer has the capability of curing the underlying cause of the disease thus reducing if not completely eliminating the potential for adverse events. Nonviral or plasmid based gene delivery offers the advantage of no immunogenecity and is highly amenable to pharmaceutical scale conditions. Although gene expression can be observed following local administration of plasmid DNA alone, formulation of the plasmid with nonionic polymers, such as PluronicRTM block copolymers, dramatically increases the amount of protein expression.;The goal of this research project is to develop a PluronicRTM block copolymer plasmid DNA formulation for intratumoral and intramuscular administration, the purpose being to have enhanced protein expression over unformulated plasmid DNA. Controlling parameters for gene expression are optimized in a brain tumor slice culture.;Historically there has been a disconnect between in vitro and in vivo gene transfer, especially for intratumoral administration. For this reason we have developed a long-term rat brain tumor slice culture. This system was used to identify key formulation components that yield maximal gene expression. The organotypic slice cultures allows for local administration of plasmid DNA within a three-dimensional plane, which is not obtainable in two-dimensional cell culture models. The brain tumor organ slice culture responds to the current need for a swift and reproducible test system for nonviral gene therapy formulations. Gene transfer to tumor cells in the rat brain tumor slice culture is enhanced when formulated with Pluronic L44. Expression is restricted to tumor cells. Further studies have been focused on improving gene transfer efficiency and validation in vivo using the rat glioma tumor model.;Characterization of the physical chemical properties of Pluronic block copolymer L44 in solution with plasmid DNA may provide insight into how the DNA-L44 enhances gene delivery to target muscle or brain cancer tissue. Characterization of the physiochemical properties of Pluronic L44 formulated with plasmid may be useful in the optimization of gene transfer following intratumoral and intramuscular administration.