Cationic polymer-mediated gene delivery to oral cancer cells


Nejat Düzgüneş: 0000-0001-6159-1391


Biomedical Sciences

Document Type

Conference Presentation

Conference Title

International Association for Dental Research (IADR)/Annual Meeting of the American Association for Dental Research (AADR) General Session and Exhibition


San Diego, CA

Conference Dates

March 16-19, 2011

Date of Presentation



Objective: We are developing efficient vectors to deliver suicide genes to oral sqamous cell carcinoma (OSCC) cells. Many oral cancer cells are resistant to lipid-mediated transfection. The cationic polyethylenimine, JetPEI mediates efficient transfection of cancer cells, but causes cytotoxicity. We examined whether chitosan, a biocompatible polymer with low toxicity, would reduce the toxicity of JetPEI, while maintaining the high transfection capability of JetPEI. We also examined whether complexation of transferrin (Tf) with JetPEI would enhance transfection and reduce toxicity. Methods: Varying amounts of chitosan (Sigma) were incubated with 1 µg pCMV.luc plasmid encoding luciferase for 30 min, and then added to 2 µl JetPEI (Polyplus). HSC-3 and H-376 OSCC cells were treated with these complexes, and gene expression was measured 48 h later, using the Luciferase Assay System (Promega) and a luminometer. Tf/JetPEI/DNA complexes (Tf-polyplexes) were prepared in two ways: (1) Tf and JetPEI were incubated for 30 min, and DNA was added. (2) JetPEI and DNA were complexed for 30 min, and Tf was added. The Alamar blue assay was used to determine cytotoxicity. Results: Chitosan inhibited transfection of HSC-3 cells in a dose-dependent manner. Tf-polyplexes prepared by method (1), but not method (2), increased transfection in both H376 and HSC-3 cells. In lipofection-resistant H-376 cells, the presence of Tf enhanced gene expression by 3.2-fold (1 µl JetPEI) and 2.5-fold (2 µl JetPEI). In HSC-3 cells, a 3.4-fold enhancement by Tf was observed with 2 µl JetPEI. Tf-polyplexes were slightly less toxic, despite the enhancement of transfection. Conclusions: The chitosan JetPEI complex was not successful in reducing cytotoxicity, contradicting results reported by another laboratory. However, complexation of Tf with JetPEI enhanced transfection activity in HSC-3 and H376 cells. This is the first report of the enhancement of cationic polymer-mediated transfection by complexation of Tf to polyethyleneimine polymers.

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