Abstract
PURPOSE: To construct an EGF receptor (EGF-R)-mediated histone H1(0)-based gene delivery system for gene therapy. METHODS: A recombinant DNA containing histone H1(0), EGF-R ligand, and endosomalytic domains was constructed in a prokaryotic vector and expressed in E. coli. Expression of the beta-galactosidase (beta-gal) gene in the tumor cells and tissues was observed after transduction of the beta-gal gene packaged by purified fusion proteins in vitro and in vivo. RESULTS: As an extension of the research on previously reported chemically synthetic composite polypeptide gene delivery systems, this genetically engineered polypeptide has proved to be capable of targeting the beta-galactosidase (beta-gal) gene into EGF-R-positive cancer cells both in vitro and in vivo. We also studied the time course of beta-gal gene expression in tumor tissues delivered in vivo by this polypeptide vector. At 24 h after administration, expression of the beta-galactosidase gene in tumor reached peak levels. The dosage optimization of administered polyplex was also investigated. The optimal dose of polyplex per mouse was 1 microg DNA packaged by 3 microg of composite polypeptide. CONCLUSIONS: The genetically engineered polypeptide based on histone H1(0) is a promising gene delivery system targeting EGF-R.