Abstract
AbstractWe previously reported that polyamidoamine STARBURST dendrimer (generation 3, G3) (dendrimer) conjugate with alpha-cyclodextrin (alpha-CyD) having an average degree of substitution of 2.4 of alpha-CyD (alpha-CDE) provided remarkable aspects as novel carriers for DNA and siRNA. To develop novel alpha-CDE derivatives with tumor cell specificity, we prepared folate-appended alpha-CDEs (Fol-alpha-CDEs) and folate-polyethylene glycol (PEG)-appended alpha-CDEs (Fol-PalphaCs) 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-alpha-CDEs (G3, DSF 2, 5 or 7) was lower than that of &x03B1;-CDE (G3) in KB cells, folate receptor (FR)-overexpressing cancer cells. Of the three Fol-PalphaCs (G3, DSF 2, 5 or 7), Fol-PalphaC (G3, DSF 5) had the highest gene transfer activity in KB cells. The activity of Fol-PalphaC (G3, DSF 5) was significantly higher than that of alpha-CDE (G3) in KB cells, but not in A549 cells, FR-negative cells. Negligible cytotoxicity of the pDNA complex with Fol-PalphaC (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-PalphaC (G3, DSF 5) could be mediated by FR on KB cells, resulting in its efficient cellular uptake. Fol-PalphaC (G3, DSF 5) had higher binding affinity with folate binding protein (FBP) than alpha-CDE (G3), although the physicochemical properties of pDNA complex with Fol-PalphaC (G3, DSF 5) were almost comparable to that with alpha-CDE (G3), although the onset charge ratio and the compaction ability of Fol-PalphaC (G3, DSF 5) were slightly different. Fol-PalphaC (G3, DSF 5) tended to show higher gene transfer activity than alpha-CDE (G3) 12 h after intratumoral administration in mice. These results suggest that Fol-PalphaC (G3, DSF 5), not Fol-alpha-CDEs, could be potentially used as a FR-overexpressing cancer cell-selective DNA carrier.
Highlights
Polyamidoamine STARBURSTTM dendrimers are biocompatible, nonimmunogenic and water-soluble, and possess terminal modifiable amine functional groups for bearing various targeting or guest molecules.[1]
In the case of folate-PEG-appended α-CDEs (Fol-PαC) (G3), Fol-PEG-COOH was firstly prepared by using ω-amino-α-carboxyl polyethylene glycol (PEG, MW = 3,290 Da), and the preparation of Fol-PEG-COOH was confirmed by the MALDI-TOF-Mass spectrum (Supplementary Fig. 1)
A carboxyl group of the Fol-PEG-COOH was condensed with primary amino group of α-CDE (G3, degree of substitution (DS) of α-CyD=2.4), and the resulting conjugates were purified by a dialysis (MWCO = 15,000) (Fig. 1)
Summary
Polyamidoamine STARBURSTTM dendrimers (dendrimers) are biocompatible, nonimmunogenic and water-soluble, and possess terminal modifiable amine functional groups for bearing various targeting or guest molecules.[1]. Cyclodextrins (CyDs) are cyclic (α-1,4)-linked oligosaccharides of α-D-glucopyranose containing a hydrophobic central cavity and hydrophilic outer surface, and they are known to be able to act as host molecules.[7,8,9] CyDs have recently been applied to gene transfer and oligonucleotide delivery.[10,11,12,13] We previously reported that of various dendrimer conjugates with α-CyD (α-CDE), α-CDE (G3) with the degree of substitution (DS) of 2.4 was revealed to have the highest transfection efficiency in vitro and in vivo with low cytotoxicity.[14,15,16] we previously reported the potential use of α-CDEs bearing galactose (Gal-α-CDE), mannose (Man-α-CDE) or lactose (Lac-α-CDE) with the various DS values of these sugar moieties as gene delivery carriers.[17,18,19,20]. We prepared folate-appended α-CDEs (Fol-α-CDE) and folate-PEG-appended α-CDEs (Fol-PαC) with various degrees of substitution of folate (DSF) as novel DNA carriers to clarify the effect of PEG and the DSF values, and examined in vitro and in vivo gene transfer activity, cytotoxicity, cellular uptake and the physicochemical properties
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call