Apoptin gene delivery by a PAMAM dendrimer modified with a nuclear localization signal peptide as a gene carrier for brain cancer therapy
Yoonhee Bae1,2, Jell Lee3, Changwon Kho2, Joon Sig Choi3, and Jin Han1,*
1Department of Physiology, College of Medicine, Cardiovascular and Metabolic Disease Center, Smart Marine Therapeutics Center, Inje University, Busan 47392, 2Division of Applied Medicine, Research Institute for Korea Medicine, School of Korean Medicine, Pusan National University, Busan 50612, 3Department of Biochemistry, College of Natural Sciences, Chungnam National University, Daejeon 34134, Korea
In this study, we aimed to synthesize PAMAMG3 derivatives (PAMAMG3-KRRR and PAMAMG3-HKRRR), using KRRR peptides as a nuclear localization signal and introduced histidine residues into the KRRR-grafted PAMAMG3 for delivering a therapeutic, carcinoma cell-selective apoptosis gene, apoptin into human primary glioma (GBL-14) cells and human dermal fibroblasts. We examined their cytotoxicity and gene expression using luciferase activity and enhanced green fluorescent protein PAMAMG3 derivatives in both cell lines. We treated cells with PAMAMG3 derivative/apoptin complexes and investigated their intracellular distribution using confocal microscopy. The PAMAMG3-KRRR and PAMAMG3-HKRRR dendrimers were found to escape from endolysosomes into the cytosol. The JC-1 assay, glutathione levels, and Annexin V staining results showed that apoptin triggered cell death in GBL-14 cells. Overall, these findings indicated that the PAMAMG3-HKRRR/apoptin complex is a potential candidate for an effective nonviral gene delivery system for brain tumor therapy in vitro.