Jung Seok Kim

Leukemia-specific siRNA delivery by immunonanoplexes consisting of anti-JL1 minibody conjugated to oligo-9 Arg-peptides

Targeted mRNA degradation by short interfering RNAs (siRNAs) offers a great potential to treat cancers. siRNA therapeutics for leukemias are, however, hindered by poor intracellular uptake, limited blood stability and nonspecific delivery. To solve these problems, we developed an anti-JL1 immunonanoplex (antibody-coupled nanocomplex) for siRNA delivery using anti-JL1 minibody (leukemia cell-specific minibody) conjugated to oligo-9-Arg peptide (9R) for effective siRNA delivery to leukemic cells. The anti-JL1 immunonanoplexes were able to deliver siRNA specifically to leukemic cells (CEM and Jurkat), but not to control cancer cells (H9). According to FACS and confocal microscopic analysis, siRNAs delivered by immunonanoplex particles were rapidly taken up by the JL1-positive cancer cells in 2 h. Furthermore, we showed that the anti-JL1 immunonanoplexes were effectively targeted to JL1-positive cells (CEM) inoculated in the mouse bone marrow. These results suggest that the anti-JL1 immunonanoplex is a powerful siRNA delivery system for human leukemia therapies.

Targeted gene therapy of LS174 T human colon carcinoma by anti-TAG-72 immunoliposomes.

Anti-tumor-associated glycoprotein (TAG)-72 PEG-immunoliposomes (PILs) were prepared by conjugation of Fab′ fragments of recombinant humanized monoclonal antibody, HuCC49, to sterically stabilize unilamellar liposomes (90–110 nm in diameter) to target TAG-72-overexpressing cancer cells. The liposomes consisted of 1-palmitonyl-2-oleoyl-sn-glycerol-3-phosphocholine (POPC), 92 mol percent, O,O′-dymyrisyl-N-lysyl aspartate (DMKD cationic lipid), 4 mol percent, distearoyl-phosphatidyl-ethanolamine-polyethylene glycol 2000 (DSPE-PEG2000), 3 mol percent and DSPE-maleimide (DSPE-PEG2000-Mal), 1 mol percent. These anti-TAG-72 PILs were able to adhere to the surface of TAG-72-overexpressing LS174 T human colon cancer cells more effectively than conventional liposomes. Also, in vitro gene transfection of the LS174 T cells by the anti-TAG-72 PILs in the presence of a high concentration of fetal bovine serum (up to 60%) was greater than that by conventional cationic lipoplexes. Intravenously administered anti-TAG-72 PILs efficiently localized in the LS174 T tumor tissues, while the non-targeted conventional liposomes did not. Intravenous administration of the anti-TAG-72 PILs containing plasmids encoding antiangiogenic proteins, such as angiostatin K1/3, endostatin and saxatilin, significantly inhibited in vivo growth of LS174 T tumors and angiogenesis in the tumor tissues. These results demonstrated the potential of TAG-72-mediated targeting of immunoliposomes as a modality for systemic gene delivery to human colon cancer cells.

Hepatic control elements promote long‐term expression of human coagulation factor IX gene in hydrodynamically transfected mice

Long‐term expression of the delivered target gene is critical for successful gene therapy. Recently, hepatic control region I (HCR I) originating from the apolipoprotein (apo)C‐I pseudogene was shown to be a critical element for long‐term gene expression in the liver of mice. HCR II is another hepatic control region of apoC‐I.

Sendai viroplexes for epidermal growth factor receptor-directed delivery of interleukin-12 and salmosin genes to cancer cells.

The effective delivery of therapeutic genes to target cells has been a fundamental goal in cancer gene therapy because of its advantages with respect to both safety and transfection efficiency. In the present, study we describe a tumor‐directed gene delivery system that demonstrates remarkable efficacy in gene delivery and minimizes the off‐target effects of gene transfection.

Sendai Viroplexes for EGF Receptor‐directed Delivery of IL12 and Salmosin Genes to Cancer Cells

The effective delivery of therapeutic genes to target cells has been a fundamental goal in cancer gene therapy because of its advantages with respect to both safety and transfection efficiency. In the present, study we describe a tumor‐directed gene delivery system that demonstrates remarkable efficacy in gene delivery and minimizes the off‐target effects of gene transfection.

Tumor-specific delivery of therapeutic siRNAs by anti-EGFR immunonanoparticles

Background Efficient target-specific siRNA delivery has always been a primary concern in the field of siRNA clinical application. Purpose In this study, four different types of anti-epidermal growth factor receptor (EGFR) antibody-conjugated immunonanoparticles were prepared and tested for cancer cell-targeted therapeutic siRNA delivery. Materials and methods The prepared nanoparticles encapsulating siRNAs were character-ized by gel retardation and particle analysis using a Zetasizer. In vitro transfection and reduction of target genes, vimentin and JAK3, were determined using quantitative reverse transcription polymerase chain reaction. In vivo tumor targeting and antitumoral efficacies of the nanoparticles were evaluated in mice carrying tumors. Results Among these immunonanoparticles, anti-EGFR immunolipoplexes and immunoviroplexes exhibited remarkable cell binding and siRNA delivery to EGFR-expressing tumor cells compared to immunoliposomes and immunovirosomes. Especially, the anti-EGFR immunoviroplexes exhibited the most efficient siRNA transfection to target tumor cells. Therefore, antitumoral vimentin and Janus kinase-3 siRNAs were loaded in the anti-EGFR immunolipoplexes and immunoviroplexes, which were tested in mice carrying SK-OV-3 tumor xenografts. In fact, the therapeutic siRNAs were efficiently delivered to the tumor tissues by both delivery vehicles, resulting in significant inhibition of tumor growth. Moreover, administration of doxorubicin in combination with anti-EGFR immunoviroplexes resulted in remarkable and synergistic tumor growth inhibition. Conclusion This study provides experimental proof that cancer cell-targeted immunoviroplexes are an efficient siRNA delivery system for cancer therapy. Moreover, this study also suggests that a combination of conventional chemotherapy and tumor-directed anticancer siRNA therapy would be a better modality for cancer treatment.

Anti-EGFR immunonanoparticles containing IL12 and salmosin genes for targeted cancer gene therapy

Tumor-directed gene delivery is of major interest in the field of cancer gene therapy. Varied functionalizations of non-viral vectors have been suggested to enhance tumor targetability. In the present study, we prepared two different types of anti-EGF receptor (EGFR) immunonanoparticles containing pDNA, neutrally charged liposomes and cationic lipoplexes, for tumor-directed transfection of cancer therapeutic genes. Even though both anti-EGFR immunonanoparticles had a high binding affinity to the EGFR-positive cancer cells, the anti-EGFR immunolipoplex formulation exhibited approximately 100-fold higher transfection to the target cells than anti-EGFR immunoliposomes. The lipoplex formulation also showed a higher transfection to SK-OV-3 tumor xenografts in mice. Thus, IL12 and/or salmosin genes were loaded in the anti-EGFR immunolipoplexes and intravenously administered to mice carrying SK-OV-3 tumors. Co-transfection of IL12 and salmosin genes using anti-EGFR immunolipoplexes significantly reduced tumor growth and pulmonary metastasis. Furthermore, combinatorial treatment with doxorubicin synergistically inhibited tumor growth. These results suggest that anti-EGFR immunolipoplexes containing pDNA encoding therapeutic genes could be utilized as a gene-transfer modality for cancer gene therapy.