Liver Cancer Cell Targeting Gene Delivery Using Lactobionic Acid-Functionalized Dendrimers As Nonviral Vectors

Gene therapy is a very useful approach to correcting or compensating the genetic defects caused by the disease through introducing therapeutic genes into target cells to cure the disease. Now gene therapy has been widely used in treating genetic disease, tumor and viral disease. Transporting the therapeutic genes into target cells to ensure the therapeutic genes to be expressed efficiently is a key issue to the gene therapy, of which the selection and construction of the gene vectors are very important.In this study, we reported a new gene delivery vector based on lactobionic acid-functionalized amine-terminated generation5poly(amidoamine) dendrimers (G5.NH2-La), through introducing the lactobionic acid (La) moieties on the surface of dendrimers. The unmodified PAMAM dendrimers were used as a control to study the impact of introduction of lactobionic acid on the gene transfection and targeting efficiency. The G5.NH2-La/pDNA and G5.NH2/pDNA complexes with different N/P ratios were characterized by agarose gel retardation assay, atomic force microscopic imaging, light scattering and zeta potential measurements. Then, the gene transfection and the hepatocyte-targeted function of the G5.NH2-La vectors were evaluated by firefly luciferase (Luc) expression, EGFP gene expression assay, cellular uptake of G5.NH2-La/pDNA polyplexes and competition assay.G5.NH2-La dendrimers are able to compact the pDNA effectively, better than the unmodified G5.NH2dendrimers. The size and zeta potential of G5.NH2-La/pDNA complexes are smaller and lower than that of G5.NH2/pDNA complexes, which are good for the improvement of gene transfaction. MTT colorimetric assay show that G5.NH2-La dendrimers almost have no toxicity to HepG2cells in the given concentration range. Both Luc assay and fluorescence microscopic imaging of the EGFP expression indicate that G5.NH2-La dendrimers have high efficiency as vectors. Competition assay with the presence of excess La demonstrates that G5.NH2-La dendrimers have the ability of targeting HepG2cells in high efficiency. G5.NH2dendrimers have certain toxicity caused by its positive charges and have no ability of targeting to liver cancer cells The defects of G5.NH2dendrimers influence its application as gene transfection vectors. With almost no toxicity and favorable targeting ability, G5.NH2-La dendrimers may have the potential to be used as a new gene delivery vector for targeted gene therapy of liver cancer cells.