Novel Antitumor Strategy Utilizing a Plasmid Expressing a Mycobacterium tuberculosis Antigen as a "Danger Signal" to Block Immune Escape of Tumor Cells.

Immune escape of tumor cells is one of the main obstacles hindering the effectiveness of cancer immunotherapy. We developed a novel strategy to block immune escape by transfecting tumor cells in vivo with genes of pathogenic antigens from Mycobacterium tuberculosis (TB). This induces presentation of the TB antigen on tumor cell surfaces, which can be recognized by antigen presenting cells (APCs) as a "danger signal" to stimulate antitumor immune response.

Highly Effective Non-Viral Antitumor Gene Therapy System Comprised of Biocompatible Small Plasmid Complex Particles Consisting of pDNA, Anionic Polysaccharide, and Fully Deprotected Linear Polyethylenimine.

We have reported that ternary complexes of plasmid DNA with conventional linear polyethylenimine (l-PEI) and certain polyanions were very stably dispersed, and, with no cryoprotectant, they could be freeze-dried and re-hydrated without the loss of transfection ability. These properties enabled the preparation of a concentrated suspension of very small pDNA complex, by preparing the complexes at highly diluted conditions, followed by condensation via lyophilization-and-rehydration procedure. Recently, a high potency linear polyethylenimine having no residual protective groups, i.

Oncolytic plasmid: A novel strategy for tumor immuno-gene therapy.

The oncolytic virus is expected to proliferate in and destroy tumor cells. The virus is also thought to generate antitumor immunity. Virally infected tumor cells express viral antigens on their surfaces.

Antitumor effect of chondroitin sulfate-coated ternary granulocyte macrophage-colony-stimulating factor plasmid complex for ovarian cancer.

Background: Although replication-competent viruses have been developed for treating cancers, their cytotoxic effects are insufficient as a result of infection inhibited by the generation of neutralizing antibodies, and systemic administration is difficult as a result of the life-threatening serious side-effects of virus-induced cytokine surge. To overcome these critical problems, we devised a plasmid/polycation/polyanion complex and assessed the potential of ternary plasmid complexes coated with chondroitin sulfate in gene therapy for ovarian cancer. The antitumor effects of chondroitin sulfate-coated complex as an anionic component were compared with those of hyaluronic acid on ovarian cancer.

Loosening of DNA/polycation complexes by synthetic polyampholyte to improve the transcription efficiency: effect of charge balance in the polyampholyte.

High mobililty group proteins are amphoteric nuclear proteins that are known to unfold chromatin to stimulate transcription. To mimic their structures, we synthesized the novel polyethylene glycol (PEG) derivatives, PEG-ACs, consisting of both amino- and carboxyl-pendants in various ratios, and their loosening and transcription-improving activity on the DNA complex was examined. Fluorescence anisotropy measurement revealed that anionic PEG-ACs with more carboxyls than amines could efficiently loosen the DNA/polyethyleneimine complex.

Preparation of a novel adenovirus formulation with artificial envelope of multilayer polymer-coatings: therapeutic effect on metastatic ovarian cancer.

Layer-by-layer deposition of the ionic polymers onto adenovirus particles afforded the multilayer-coated virus vectors. The infectivity of the virus in the presence of anti-adenovirus antibody increased as the layer number and the viruses with five or six polymer layers allowed relatively high efficiency of reporter gene expression in vitro. Therapeutic effect of the intraperitoneal injection of the oncolytic adenovirus with quintal polymer multilayers on the mice bearing intraperitoneal metastatic ovarian cancer was examined.

DNA/polyethyleneimine/hyaluronic acid small complex particles and tumor suppression in mice.

The highest barriers for non-viral vectors to an efficient in vivo gene transfection would be (1) non-specific interaction with biological molecules, and (2) large size of the DNA complex particles. Protective coating of the DNA/polyethyleneimine (PEI) complexes by hyaluronic acid (HA) effectively diminished the adverse interactions with biological molecules. Here we found HA also protected the DNA/PEI complexes against aggregation and inactivation through lyophilization-and-rehydration procedures.

Improvement of transcription- and transfection-efficiency by synthetic polyampholytes.

Water-soluble PEG derivatives having both amino- and carboxyl-pendants (PEG-ACs) were synthesized, and examined for their transcription- and transfection-enhancing activity on DNA/polycation complexes. PEG-AC could be deposited onto the surface of DNA/polyethylenimine(PEI) complexes, and enhanced their transcriptional activity. Fluorescence anisotropy study showed that the amphoteric PEG-AC loosened the tightly compacted DNA/PEI complex to facilitate the approach of transcriptional factors.

Highly efficient in vivo gene transfection by plasmid/PEI complexes coated by anionic PEG derivatives bearing carboxyl groups and RGD peptide.

A new class of an anionic poly (ethylene glycol) derivative, PEG-Suc, bearing 17.7 pairs of carboxylic acid-side chains was synthesized. PEG-Suc deposited onto the DNA/polyethyleneimine complexes without destroying them even at high dose ratio.