P53-Derived peptides conjugation to PEI: an approach to producing versatile and highly efficient targeted gene delivery carriers into cancer cells

<p><b><i>Objectives</i>:</b> Targeted delivery of cytotoxic drugs or therapeutic antisense RNAs into specific cells is a major bottleneck in cancer therapy. To overcome this problem and improve the specificity for cancer cells, we describe a new-targeted delivery system using p53-derived peptides, namely PNC 27 and PNC 28. These peptides target HDM-2 on the surface of cancer cells. HDM-2 is overexpressed on the surface of cancerous cells, but not present on the untransformed cells.</p> <p><b><i>Methods</i>:</b> To determine HDM-2-expressing cells, we used immunocytochemistry and flow cytometry analysis on nine cell lines including MCF-7 and NIH-3t3. Conjugation of peptides to vectors was confirmed using reverse-phase high-pressure liquid chromatography (RP-HPLC). Physicochemical properties of vector/DNA complexes including particle size, surface charge and DNA condensation ability were determined. In transfection studies, three plasmids were used including luciferase, pEGFP and shRNA plasmid against Bcl-XL mRNA. The level of Bcl-XL expression was determined by real-time PCR and western blot techniques.</p> <p><b><i>Results</i>:</b> The results of gene delivery and shRNA-based gene silencing studies indicated that conjugation of PNC peptides could enhance gene delivery efficiently with high-targeted activity exclusively into cancer cells.</p> <p><b><i>Conclusion</i></b>: Our results strongly indicated that this targeting system could be utilized as an efficient targeting method for most cancer cells.