Receptor-Mediated Gene Delivery Employing Adenovirus-Polylysine-DNA Complexes

Abstract

Gene transfer to eucaryotic cells may be accomplished by capitalizing on endogenous cellular pathways of macromolecular transport. In this regard, gene transfer has been accomplished via the receptor-mediated endocytosis pathway employing molecular conjugate vectors (Wu and Wu, 1987; Wu et al., 1989; Wagner et al., 1990; Wagner et al., 1991b; Cotten et al., 1990; Curiel et al., 1992a; Huckett et al., 1990; Rosenkranz et al., 1992). The molecular conjugate is a synthetic bifunctional agent employed to serve two functions: binding of the heterologous DNA to form a conjugate-DNA complex, and attachment of the conjugate-DNA complex to the target cell to facilitate internalization. The initial step of binding the heterologous DNA to form a conjugate-DNA complex is mediated through a domain of the conjugate comprised by a polycation amine, such as polylysine. This electrostatic interaction between the negatively charged DNA and the positively charged DNA-binding domain serves not only to bind the DNA, but also to condense it into a compact toroid structure (Wagner et al., 1991a). As the ligand is covalently linked to the polylysine DNA-binding domain, after binding of the DNA, at least a portion of the ligand is presented on the surface of the complex, free to interact with its cognate receptor. The attachment of the conjugate-DNA complex to the target cell is then mediated through the specificity of the ligand domain for its corresponding receptor. Thus, after the conjugate-DNA complex accomplishes attachment, it is internalized through the corresponding cellular transport pathway.