Gene delivery with biocompatible cationic polymer: pharmacogenomic analysis on cell bioactivity

The availability of non-viral gene delivery systems is determined by their capacity and safety during gene introduction. In this study, the safety issues of polyplex were analyzed from the standpoint of the biomolecular mechanisms. P[Asp(DET)], a newly developed polymer, polyasparagine carrying the N-(2-aminoethyl)aminoethyl group as the side chain which was recently revealed to show good transfection efficiency to primary cells, was compared to conventional linear poly(ethylenimine) (LPEI). After transfection toward a bioluminescent cell line, P[Asp(DET)] maintained the expression level of stably expressing luciferase. In contrast, LPEI showed a decrease in the luciferase expression, while the similar expression of exogenous reporter gene was obtained. Evaluation of the housekeeping genes expression as well as the profiles of pDNA uptake after transfection suggested the time-dependent toxicity of LPEI that perturbs cellular homeostasis. Consistently, the induction of osteogenic differentiation by functional gene introduction was achieved only by P[Asp(DET)], even though appreciable expression of the gene was achieved by LPEI. It is crucial that this aspect of safety be taken into account, especially when the gene introduction is applied to primary cells to regulate such cell function as differentiation. This biomolecular analysis focusing on cellular homeostasis is beneficial for assessing the practicability of the gene delivery systems for clinical application.