Recombinant Adenovirus Stem Cell Gene Delivery

The adenovirus vector is modified with tumor-specific targeting ligands (such as RGD peptides, antibodies, or aptamers) on its surface, enabling it to selectively bind to and accumulate in tumor tissues while avoiding healthy liver tissue. This local targeting capability allows systemic administration to deliver the virus preferentially to the tumor site, maintaining gene delivery efficiency while reducing hepatotoxicity.

A targeting intermediary molecule (such as a peptide ligand, antibody fragment, or carbohydrate moiety) is introduced between the adenovirus capsid and the cellular receptor, mediating selective binding to tumor cells. This intermediary enables the virus to navigate through the bloodstream without being taken up by liver cells, while specifically recognizing and binding to receptors overexpressed on tumor cell surfaces.

Instead of using the conventional adenovirus capsid structure that is readily recognized by neutralizing antibodies, the invention inverts the approach by using pseudotyped adenoviruses with alternative viral envelopes (such as vesicular stomatitis virus G protein or lentiviral envelopes) that are not recognized by anti-adenovirus neutralizing antibodies. This inversion of the capsid structure allows the virus to evade pre-existing immunity while retaining gene delivery capability and extending in-vivo retention time.

The surface properties and structural parameters of the adenovirus are modified by changing the capsid proteins or adding PEGylated moieties, which alter the virus's immunogenicity profile. These parameter changes reduce recognition by neutralizing antibodies and complement system, thereby extending the circulation half-life and in-vivo retention time of the virus while maintaining its ability to deliver therapeutic genes.

The adenovirus vector is engineered with multiple targeting moieties or a universal targeting ligand that can bind to receptors present on both mesenchymal stem cells and tumor cells. This multi-functional targeting approach allows the virus to efficiently infect MSCs for systemic administration while maintaining the ability to deliver genes to tumor cells, overcoming the receptor deficiency issue in MSCs.

Mesenchymal stem cells are pre-modified or pre-conditioned before virus administration to enhance their susceptibility to adenovirus infection. This preliminary action may involve upregulating cellular receptors (such as CAR or integrins) through cytokine treatment or genetic modification, or coating the cells with receptor ligands, thereby enabling efficient adenovirus transduction despite the naturally low receptor expression on MSCs.