A novel gene delivery system using urothelial tissue engineered neo- organs

Purpose: Presently gene delivery is most effectively achieved by ex vivo gene transfer, which includes removal of the target tissue, in vitro gene delivery to the target cells, possible selection to enhance the proportion of transfected cells and reintroduction of the gene modified cells. Reintroduction of transformed cells in vive has been a challenging task. Based on the feasibility of tissue engineering techniques in which cells seeded on biodegradable polymer scaffolds form tissue when implanted in vivo, we explored the possibility of developing a neo-organ system for in vive gene therapy. Materials and Methods: Normal human urothelial cells were harvested, expanded in vitro and seeded on biodegradable polymer scaffolds. The cell- polymer complex was then transfected with PGL3-luc, pCMV-luc and pCMVβ-gal promoter reporter gene constructs. The transfected cell-polymer scaffolds were then implanted in athymic mice and the engineered tissue was retrieved 0, 1, 3, 5 and 7 days after implantation. Results: The reporter gene assay demonstrated an expression of luciferase activity at days 1, 3, 5 and 7 with the peak at day 5. X-gal and β-galactosidase antibody assays stained positive on the deoxyribonucleic acid treated transfection. Conclusions: Successful gene transfer can be achieved using biodegradable polymer scaffolds as a urothelial cell delivery vehicle. The transfected cell- polymer scaffold forms an organ-like structure with functional expression of the transfected genes. This study demonstrates that urothelial tissue engineered gene transfer is safe and effective.