Biol Pharm Bull. 28(3):500-505 (2005).

Enhancing Effects of Galactosylated Dendrimer/a-Cyclodextrin Conjugates on Gene Transfer Efficiency.

Wada K, Arima H, Tsutsumi T, Hirayama F, Uekama K.

Graduate School of Pharmaceutical Sciences, Kumamoto University.

To improve in vitro gene transfer efficiency and/or achieve cell-specific gene delivery of polyamidoamine (PAMAM) starburst dendrimer (generation 2, G2) conjugate with a-cyclodextrin (a-CDE conjugate (G2)), we prepared a-CDE conjugate bearing galactose (Gal-a-CDE conjugates) with the various degrees of substitution of the galactose moiety (DSG) as a novel non-viral vector. The agarose gel electrophoretic studies revealed that Gal-a-CDE conjugates formed complexes with plasmid DNA (pDNA) and protected the degradation of pDNA by DNase I, but these effects impaired as the DSG value increased. Dendrimer and a-CDE conjugate exerted pDNA condensation through the complexation, but Gal-alpha-CDE conjugates did not. Gal-a-CDE conjugate (DSG 4) was found to have much higher gene transfer activity than dendrimer, a-CDE conjugate and Gal-alpha-CDE conjugates (DSG 8, 15) in HepG2, NIH3T3 and A549 cells, which are independent of the expression of the asialoglycoprotein receptor. Transfection activity of Gal-a-CDE conjugate (DSG 4) was insensitive to the existence of competitors (asialofetuin and galactose) and serum. In addition, no cytotoxicity after transfection of the complex of pDNA with Gal-a-CDE conjugate (DSG 4) was observed. These results suggest the potential use of Gal-a-CDE conjugate (DSG 4) as a non-viral vector in various cells.