Abstract B90: Nonviral delivery of apoptin for the treatment of brain tumor in a newly established brain tumor xenograft.

Abstract

Abstract We established a brain tumor xenograft to examine the application of gene therapy utilizing a tumor selectively killing gene together with a nonviral gene delivery carrier to treat brain tumor. To do so, we recombined the therapeutic gene apoptin with the JDK vector and delivered it into human brain tumor cells (U87MG) using PAM-RG4 as the gene delivery carrier. Studies in vitro showed that the PAM-R G4/Apoptin polyplex exhibited particularly high transfection activity of over 40% based on fluorescence-activated cell sorting (FACS) analysis and lower cytotoxicity than other control agents. Also, TUNEL assay and DAPI staining verified that tumor cells had undergone apoptosis, which was induced by the apoptin gene. Caspase-3 activity was about two times higher in the therapeutic group. For in vivo studies, the PAM-R G4/Apoptin polyplex was injected into the tumor, which was induced by injecting U87MG cells into the left flank of nude mice and letting them grow to a certain size. The size of the tumor exponentially grew with time in the control groups whereas the treated group did not exhibit any tumor growth. H&E staining and EGFR immunohistochemistry confirmed the existence of the tumor in the control groups and showed that there was no tumor in the treated group. Furthermore, no specific edema, irritation or other kind of harm to the skin could be observed when the polyplex was injected. After reverse-transcript PCR analysis, to verify the expression of apoptin in vivo, TUNEL assay and DAPI staining were, again, utilized to confirm the event of apoptosis in the therapeutic group. These findings indicate that the PAM-RG4/Apoptin polyplex is a very strong candidate for brain tumor therapeutics, due to the synergistic effect of the carrier's high transfection efficiency in neuron cells and the gene's selective apoptosis-inducing activity in tumor cells. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2011 Nov 12-16; San Francisco, CA. Philadelphia (PA): AACR; Mol Cancer Ther 2011;10(11 Suppl):Abstract nr B90.