The administration of naked plasmid DNA into the liver induces antitumor innate immunity in a murine liver metastasis model

Antitumoral efficacy by systemic delivery of heparin conjugated polyethylenimine-plasmid interleukin-15 complexes in murine models of lung metastasis

Gene therapy shows promising application in cancer therapy, but the lack of an ideal gene delivery system is still a tough challenge for cancer gene therapy. Previously, we prepared a novel cationic nanogel, heparin-polyethylenimine (HPEI), which had potential application in gene delivery. In the present study, we constructed a plasmid with high expression efficiency of interleukin-15 (IL15) and investigated the effects HPEI-plasmid IL15 (HPEI-pIL15) complexes on the distribution level of the lung. We then evaluated the anticancer effect of HPEI-pIL15 complexes on lung metastases of B16-F10 melanoma and CT26 colon carcinoma. These results demonstrated that intravenous injection of the HPEI-pIL15 complex exhibited the highest plasmid distribution level in the lung compared with that of PEI2K-pIL15 and PEI25K-pIL15, and mice treated with HPEI-pIL15 had a lower tumor metastasis index compared with other treatment groups. Moreover, the number of natural killer cells, which were intermingled among the tumor cells, and the level of tumor necrosis factor-α and interferon-γ in the serum also increased in the pIL15-treated mice. Furthermore, the cytotoxic activity of spleen cells also increased significantly in the HPEI-pIL15 group. In addition, induction of apoptosis and inhibition of cell proliferation in lung tumor foci in the HPEI-pIL15 group was observed. Taken together, treating lung metastasis cancer with the HPEI nanogels delivered by plasmid IL15 might be a new and interesting cancer gene therapy protocol.

Hydrodynamic gene delivery and its applications in pharmaceutical research

Hydrodynamic delivery has emerged as the simplest and most effective method for intracellular delivery of membrane-impermeable substances in rodents. The system employs a physical force generated by a rapid injection of large volume of solution into a blood vessel to enhance the permeability of endothelium and the plasma membrane of the parenchyma cells to allow delivery of substance into cells. The procedure was initially established for gene delivery in mice, and its applications have been extended to the delivery of proteins, oligo nucleotides, genomic DNA and RNA sequences, and small molecules. The focus of this review is on applications of hydrodynamic delivery in pharmaceutical research. Examples are provided to highlight the use of hydrodynamic delivery for study of transcriptional regulation of CYP enzymes, for establishment of animal model for viral infections, and for gene drug discovery and gene function analysis.

Murine pneumotropic virus chimeric Her2/neu virus-like particles as prophylactic and therapeutic vaccines against Her2/neu expressing tumors

Virus-like particles (VLPs) have increasingly attracted attention as DNA-free and safe antigen carriers in tumor immunotherapy, requiring only minute amounts of antigens. Previously, we have immunized with murine polyomavirus (MPyV) VLPs carrying human Her2/neu and prevented the outgrowth of a human Her2/neu expressing tumor in a transplantable tumor model as well as outgrowth of spontaneous rat Her2/neu carcinomas in BALB-neuT mice. Here, we examine if prophylactic and therapeutic protection could be obtained with murine pneumotropic virus (MPtV) VLPs, and study the cross-reactivity between human and rat Her2/neu. VLPs from MPyV and MPtV carrying human or rat Her2/neu were tested in two transplantable tumor models against a human Her2/neu positive (D2F2/E2) and a rat Her2/neu positive tumor cell line (TUBO). Rat Her2/neu-VLPs were also tested in BALB-neuT mice. Her2/neu-MPtVLPs were as efficient as prophylactic vaccines against D2F2/E2 and TUBO as those from MPyV. Homologous Her2/neu was better than heterologous, i.e. human Her2/neu-VLPs were better than rat Her2/neu-VLPs against D2F2/E2 and vice versa. Moreover, therapeutic immunization with human Her2/neu-VLPs together with CpG given up to 6 days after challenge protected against D2F2/E2. In BALB-neuT mice, rat Her2/neu-VLPs were less efficient than human Her2/neu-VLPs used in our previous study, implying that protection seen in that study was partly due to the use of human rather than rat Her2/neu. In conclusion, Her2/neu-MPtVLPs are effective both as prophylactic and therapeutic tumor vaccines. Homologous Her2/neu-VLPs are superior to heterologous in transplantable tumor models, while the opposite is true in BALB-neuT mice.

Hydrodynamic gene delivery: its principles and applications

Efficient and safe methods for delivering genetic materials into cells must be developed before the clinical potential of gene therapy can be fully realized. Recently, hydrodynamic gene delivery using a rapid injection of a relatively large volume of DNA solution has opened up a new avenue for gene therapy studies in vivo. This method is superior to the existing delivery systems because of its simplicity, efficiency, and versatility. Wide success in applying hydrodynamic principles to delivery of DNA, RNA, proteins, and synthetic compounds, into the cells in various tissues of small animals, has inspired the recent attempts at establishing a hydrodynamic procedure for clinical use. In this review, we provide an overview of the theory and practice of hydrodynamic gene delivery so as to aid researchers for the use of this method in their pre-clinical and translational gene therapy studies.