Complexation of Apoptotic Genes with Polyethyleneimine (PEI)-Coated Poly-(DL)-Lactic-Co-Glycolic Acid Nanoparticles for Cancer Cell Apoptosis

Methods for delivering genes into the nuclei of cancer cells are desired in various clinical and therapeutic usages of non-viral vectors. The present study describes the production of surface-modified poly-(DL)-lactic-co-glycolic acid (PLGA) nanoparticles (NPs), which facilitated the delivery of specific genes into the cancer cell nuclei. Plasmid DNA (pDNA) encoding Bak and Bak-like (BL) apoptotic genes were generated and successfully delivered into cancer cell nuclei, resulting in apoptosis of the cancer cells. The abilities of Bak and BL genes to promote cancer cell (HeLa and 293T cells) apoptosis were compared. In fluorescence-activated cell sorting (FACS) analysis, approximately 61% and 51% of BL pDNAs fused with EGFP complexed PLGA NPs were transfected into 293T cells and HeLa cells, respectively; however, a low transfection efficiency was obtained for lipofectamine-complexed BL pDNAs. In both DePsipher and cytochrome c staining analysis, larger amount of apoptotic 293T and HeLa cells were observed after cell transfection with Bak and BL pDNAs complexed with PLGA NPs as compared with lipofectamine complexed with Bak and BL pDNAs or control groups. The apoptosis of 293T and HeLa cells transfected with Bak and BL against several types of non-viral vectors was detected. Western blotting, and immunohistochemical analyses showed that the complexes of biodegradable PLGA NPs coated with polyethyleneimine (PEI; M _w 25,000) Bak and BL can be formed, and used for efficient delivery of the apoptotic genes into the cell nuclei.