Nonviral gene therapy in vivo with PAM-RG4/apoptin as a potential brain tumor therapeutic

nviral gene therapy in vivo with PAM-RG4/apoptin as a potential brain tumor therapeutic Original Research (842) Total Article Views Authors: An S, Nam K, Choi S, Bai CZ, Lee Y, Park JS Published Date February 2013 Volume 2013:8 Pages 821 - 834 DOI: http://dx.doi.org/10.2147/IJN.S39072 Received: 12 October 2012 Accepted: 02 December 2012 Published: 25 February 2013 Songhie An,* Kihoon Nam,* Sunghyun Choi, Cheng Z Bai, Yan Lee, Jong-Sang Park Department of Chemistry, Seoul National University, Seoul, Republic of Korea *These authors contributed equally to this work Background: Glioma is still one of the most complicated forms of brain tumor to remove completely due to its location and the lack of an efficient means to specifically eliminate tumor cells. For these reasons, this study has examined the effectiveness of a nonviral gene therapy approach utilizing a tumor-selective killer gene on a brain tumor xenograft model. Methods and results: The therapeutic apoptin gene was recombined into the JDK plasmid and delivered into human brain tumor cells (U87MG) by using a polyamidoamine dendrimer with an arginine surface (PAM-RG4). Studies in vitro showed that the PAM-RG4/apoptin plasmid polyplex exhibited a particularly high transfection activity of >40%. Terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay, 4′,6-Diamidino-2-phenylindole (DAPI) TUNEL assay, DAPI staining, and caspase-3 activity assay verified that the tumor cells had undergone apoptosis induced by apoptin. For in vivo studies, the polyplex was injected into tumors, which were induced by injecting U87MG cells intradermally into nude mice. Based on hematoxylin and eosin staining, epidermal growth factor receptor immunohistochemistry results and tumor volume measurement results, tumor growth was effectively inhibited and no specific edema, irritation, or other harm to the skin was observed after polyplex injection. The in vivo expression of apoptin and the induction of apoptosis were verified by reverse-transcription polymerase chain reaction analysis, TUNEL assay, and DAPI staining. Conclusion: The PAM-RG4/apoptin gene polyplex is a strong candidate for brain tumor therapeutics because of the synergistic effect of the carrier's high transfection efficiency (35%–40%) in glioma cells and the selective apoptosis-inducing activity of apoptin in tumor cells.