Polyethylenimine-cyclodextrin-tegafur conjugate shows anti-cancer activity and a potential for gene delivery

Abstract

Polyethylenimine-cyclodextrin-tegafur (PEI-CyD-tegafur) conjugate was synthesized as a novel multifunctional prodrug of tegafur for co-delivery of chemotherapeutic agent tegafur and enhanced green fluorescent protein (EGFP) reporter plasmid DNA. Conjugation of tegafur to PEI-CyD via chemical linkage was characterized by (1)H NMR spectrometry and ultraviolet (UV) spectrometry. PEI-CyD-tegafur was able to condense plasmid DNA into complexes of around 150 nm with positive charge at the N/P ratio of 25, in accordance with electron microscopy observation of compact and monodisperse nanoparticles. The results of in vitro experiments showed enhanced cytotoxicity and considerable transfection efficiency in B16F10 cell line. Therefore, PEI-CyD-tegafur may have great potential as a co-delivery system with anti-cancer activity and potential for gene delivery.

Fig. 1

Synthesis of PEI-CyD-tegafur conjugate

Fig. 2

¹H NMR spectra of tegafur (a), PEI-CyD copolymer (b), and PEI-CyD-tegafur conjugate (c) in DMSO-d₆ (b′) shows the ¹H NMR spectrum of PEI-CyD copolymer in D₂O from which PEI-600/CyD molar ratio was calculated; (c′) shows the zoom spectrum of PEI-CyD-tegafur ranging from δ 5.6 to δ 8.0, which indicates the conjugation of tegafur to PEI-CyD copolymer

Fig. 3

UV spectra of PEI-CyD-tegafur conjugate, tegafur, and PEI-CyD copolymer solutions The absorbance of PEI-CyD-tegafur and tegafur solutions peaks at 274.1 and 272.3 nm, respectively

Fig. 4

DNA retardation assays of PEI-CyD (a) and PEI-CyD-tegafur (b) with increasing N/P ratios PEI-CyD and PEI-CyD-tegafur could both condense DNA at the N/P ratio of 3. 1–6 represent the N/P ratios of the lanes, respectively

Fig. 5

Physical characterization of PEI-CyD-tegafur/DNA complexes (a) Size distribution; (b) The mean particle size and the mean zeta-potential at different N/P ratios; (c) TEM image; (d) SEM image

Fig. 6

In vitro cytotoxicities of tegafur and PEI-CyD-tegafur conjugate to B16F10 (a), HT29 (b), and COS7 (c) cell lines

Fig. 7

In vitro transfection of PEI-CyD, PEI-CyD-tegafur, and PEI-25 kDa in B16F10 and COS7 cell lines