Characterization of synergistic anti-tumor effects of doxorubicin and p53 via graphene oxide-polyethyleneimine nanocarriers

Co-delivery of chemical drugs and therapeutic genes for synergistic therapy provides a promising strategy to treat devastating diseases. However, the real-time coordination patterns between chemical drugs and therapeutic genes remain poorly understood. Herein, the complexes of doxorubicin/graphene oxidepolyethyleneimine/p53 plasmid（Dox/GO-PEI/p53） were fabricated and employed to investigate the synergistic manner between Dox and p53 in the inhibition of He La cell growth. GO was conjugated with PEI to form the GO-PEI backbone as the delivery vector. The GO backbone provided surfaces with a high specific area to load Dox via the π-π stacking interaction, and was able to release Dox significantly faster at pH 5.0 than at pH 7.0, while the positively charged PEI section of GO-PEI could condense plasmids into GO-PEI/DNA nanoparticles via the electrostatic interaction. The nanoparticles efficiently mediated the transfection of DNA in He La cells, with lower cytotoxicity compared to PEI/DNA nanoparticles. Furthermore, the complexes of Dox/GO-PEI/p53 released Dox and expressed p53 gene in a sequential manner,and showed successive inhibition of the in vitro growth of He La cells. This type of drug/GO-PEI/DNA complex can be employed as a platform to investigate the coordination pattern between chemical drugs and therapeutic genes for tumor therapy.

Inhibition of HeLa cell growth by doxorubicin-loaded and tuftsinconjugated arginate-PEG microparticles

In order to improve the release pattern of chemotherapy drug and reduce the possibility of drug resistance,poly(ethylene glycol amine)(PEG)-modified alginate microparticles(ALG-PEG MPs)were developed then two different mechanisms were employed to load doxorubicin(Dox):1)forming Dox/ALGPEG complex by electrostatic attractions between unsaturated functional groups in Dox and ALG-PEG;2)forming Dox-ALG-PEG complex through EDC-reaction between the amino and carboxyl groups in Dox and ALG,respectively.Additionally,tuftsin(TFT),a natural immunomodulation peptide,was conjugated to MPs in order to enhance the efficiency of cellular uptake.It was found that the Dox-ALG-PEGTFT MPs exhibited a significantly slower release of Dox than Dox/ALG-PEG-TFT MPs in neutral medium,suggesting the role of covalent bonding in prolonging Dox retention.Besides,the release of Dox from these MPs was pH-sensitive,and the release rate was observably increased at pH 6.5 compared to the case at pH 7.4.Compared with Dox/ALG-PEG MPs and Dox-ALG-PEG MPs,their counterparts further conjugated with TFT more efficiently inhibited the growth of HeLa cells over a period of 48 h,implying the effectiveness of TFT in enhancing cellular uptake of MPs.Over a period of 48 h,Dox-ALG-PEG-TFT MPs inhibited the growth of HeLa cells less efficiently than Dox/ALG-PEG-TFT MPs but the difference was not significant(p>0.05).In consideration of the prolonged and sustained release of Dox,Dox-ALGPEG-TFT MPs possess the advantages for long-term treatment.