Tumour gene delivery -transfection efficiency and uptake process of Pegylated poly-L-lysine nanoparticles

Keywords:
pegylated poly-L-lysine, nanoparticles, macropinocytosis, in vivo tumour transfection

Abstract:
With the aim of gene transfer to tumour cells by pegylated poly-L-lysine (CK-PEG) nanoparticles, we investigated the entry mechanism and pathway taken by rhodamine labelled nanoparticles and analysed their gene delivery potential in vitro and in vivo. In vitro gene expression analysis demonstrates that the CK-PEG nanoparticles display over 20 fold higher transfection efficiency than unpegylated poly-L-lysine polyplexes. Transmission electron microscopy demonstrates that the compacted DNA nanoparticles range in length from 100-200 nm but display an average width of 20nm which is conducive to gene delivery across the NMP. Co-localisation studies suggest that the nanoparticles undergo partial trafficking in early endosomes but do not follow a clathrin dependent pathway of transfection which has been described for a number of non-viral vectors. Instead, the size of the nanoparticles promotes their distribution into macropinosomes which is further supported by inhibitor studies. Using a luciferase reporter, gene delivery via intratumoural injection to a growing subcutaneous tumour is observed in Balb/C mice. This study therefore evaluates the mode of entry taken by the CK-PEG nanoparticles and highlights their ability to deliver genes to in vivo tumours, a prospect that may be extended to a therapeutic setting.

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Nanotech 2006 Conference Program Abstract