We previously reported that
polyamidoamine STARBURST
dendrimer (generation 3, G3) (
dendrimer) conjugate with α-
cyclodextrin (α-CyD) having an average degree of substitution of 2.4 of α-CyD (α-CDE) provided remarkable aspects as novel carriers for
DNA and
small-interfering RNA. To develop novel α-CDE derivatives with
tumor cell specificity, we prepared
folate-appended α-CDEs (Fol-α-CDEs) and
folate-
polyethylene glycol (PEG)-appended α-CDEs (Fol-PαCs) with the various degrees of substitution of
folate (DSF), and evaluated in vitro and in vivo gene transfer activity, cytotoxicity, cellular association and physicochemical properties. In vitro gene transfer activity of Fol-α-CDEs (G3, DSF 2, 5 or 7) was lower than that of α-CDE (G3) in KB cells,
folate receptor (FR)-overexpressing
cancer cells. Of the three Fol-PαCs (G3, DSF 2, 5 or 7), Fol-PαC (G3, DSF 5) had the highest gene transfer activity in KB cells. The activity of Fol-PαC (G3, DSF 5) was significantly higher than that of α-CDE (G3) in KB cells, but not in A549 cells, FR-negative cells. Negligible cytotoxicity of the plasmid
DNA (pDNA) complex with Fol-PαC (G3, DSF 5) was observed in KB cells or A549 cells up to a charge ratio of 100/1 (carrier/pDNA). The cellular association of the pDNA complex with Fol-PαC (G3, DSF 5) could be mediated by FR on KB cells, resulting in its efficient cellular uptake. Fol-PαC (G3, DSF 5) had a higher binding affinity with
folate-
binding protein than α-CDE (G3), although the physicochemical properties of pDNA complex with Fol-PαC (G3, DSF 5) were almost comparable to that with α-CDE (G3), although the onset charge ratio and the compaction ability of Fol-PαC (G3, DSF 5) were slightly different. Fol-PαC (G3, DSF 5) tended to show a higher gene transfer activity than α-CDE (G3) 12 h after intratumoral administration in mice. These results suggest that Fol-PαC (G3, DSF 5), not Fol-α-CDEs, could be potentially used as a FR-overexpressing
cancer cell-selective
DNA carrier.