Development of a Nature-Inspired Vector for Targeted Systemic Breast Cancer Gene Therapy

Abstract

Abstract : The purpose of this research was to develop a gene delivery system that can target breast cancer cells specifically and transfect them efficiently. A biomimetic vector was genetically engineered to contain at precise locations: a) an adenovirus micro peptide to condense pDNA into nanosize particles, b) a synthetic peptide to target breast cancer cells, c) a pH-responsive synthetic fusogenic peptide to disrupt endosome membranes and facilitate escape of the nanoparticles into the cytosol, and d) a nuclear localization signal from human immuno-deficiency virus to transfer the genetic material to the nucleus. The vector was cloned and expressed in E.coli expression system followed by purification. The purified vector was able to condense plasmid DNA (pDNA) into nanosize carriers (~60nm) and protect pDNA from serum endonucleases. The vector could target ZR-75-1 breast cancer cells and internalize, efficiently disrupt endosome membranes and escape into cytosol, and mediate efficient gene transfer. The vector did not show significant binding to normal mammary cells. The vector did not show any significant cell toxicity. When complexed with plasmid DNA encoding TRAIL gene, the vector was able to kill ca. 60% of the ZR-75-1 cancer cells.