Tailor-made fibroblast-specific and antibiotic-free interleukin 12 plasmid for gene electrotransfer-mediated cancer immunotherapy

Publication date: Available online 24 November 2016 Source:Plasmid Author(s): Urska Kamensek, Natasa Tesic, Gregor Sersa, Spela Kos, Maja Cemazar Electrotransfer mediated delivery of interleukin-12 (IL-12) gene, encoded on a plasmid vector, has already been demonstrated to have a potent antitumor efficacy and great potential for clinical application. In the present study, our aim was to construct an optimized IL-12-encoding plasmid that is safe from the regulatory point of view. In light of previous studies demonstrating that IL-12 should be released in a tumor localized manner for optimal efficacy, the strong ubiquitous promoter was replaced with a weak endogenous promoter of the collagen 2 gene, which is specific for fibroblasts. Next, to comply with increasing regulatory demands for clinically used plasmids, the expression cassette was cloned in a plasmid lacking the antibiotic resistance gene. The constructed fibroblast-specific and antibiotic-free IL-12 plasmid was demonstrated to support low IL-12 expression after gene electrotransfer in selected cell lines. Furthermore, the removal of antibiotic resistance did not affect the plasmid expression profile and lowered its cytotoxicity. With optimal IL-12 expression and minimal transgene non-specific effects, i.e., low cytotoxicity, the constructed plasmid could be especially valuable for different modern immunological approaches to achieve localized boosting of the host’s immune system.
Source: Plasmid - Category: Biotechnology Source Type: research