Byungdug Jun

Design of Polymeric Carriers for Cancer-Specific Gene Targeting: Utilization of Abnormal Protein Kinase Cα Activation in Cancer Cells

We succeeded in cancer cell specific gene expression by using a polyplex responsive to protein kinase Calpha, which is activated in various types of cancer cells.

Protein kinase Cα-specific peptide substrate graft-type copolymer for cancer cell-specific gene regulation systems

We recently proposed a novel gene regulation system responding to specifically and abnormally activated intracellular enzymes in diseased cells. In the present study, we focused on protein kinase C (PKC)alpha, which is hyper-activated in most tumor cells, as a trigger for transgene regulation. We prepared cationic copolymers comprising hydrophilic and neutral polymers in main chains and cationic peptide substrates with different contents in side chains. Our copolymer with high peptide content (>3 mol%) condensed with pDNA more weakly than with poly(L-lysine) (pLL) having a similar molecular weight, but gene suppression was nearly identical to that of pLL, probably due to the steric hindrance of the main chains in our copolymer. Steric hindrance of the main chains barely affected the phosphorylation reaction of the pendant peptide. In cell and mouse experiments, higher gene expression was observed in complexes of pDNA with copolymers pended PKC alpha-specific substrate peptide than that in complexes with negative copolymers pended peptide substituted phosphorylation site of serine residues with alanine. These results indicate that our system can recognize intracellular PKC alpha as a trigger to regulate transgene expression, and may be useful for tumor gene therapy.

Hepatoma-targeted gene delivery using a tumor cell-specific gene regulation system combined with a human liver cell-specific bionanocapsule

Hepatoma (hepatocellular carcinoma) is the most common type of malignant tumor originating in the liver and has a relatively low 5-year survival rate. The development of hepatoma-targeted therapy is needed to increase treatment efficiency and to reduce the incidence of undesirable side effects. In this study we developed a novel hepatoma-targeted gene delivery system. The gene delivery system was prepared by combining a human liver cell-specific bionanocapsule (BNC) and a tumor cell-specific gene regulation polymer, which responds to hyperactivated protein kinase C alpha in hepatoma cells. The complex of the polymer-DNA with BNCs was delivered into cells and tissues. The developed system showed increased transfection efficiency and resulted in cell-specific gene expression in hepatoma cells and tissues (HuH-7), but no gene expression in normal human hepatocytes or human epidermoid tumor cells (A431). The combination of a tumor cell-specific gene regulation system responding to protein kinase C alpha and BNCs showed excellent potential for the selective treatment of hepatomas. The system could be a useful method with applications in hepatoma-specific gene therapy and molecular imaging. From the clinical editor: Hepatocellular carcinoma is the most common type of malignant tumor in the liver with a low 5-year survival rate. In this study, a novel hepatoma-targeted gene delivery system was prepared by combining a human liver cell-specific bionanocapsule and a tumor cell-specific gene regulation polymer, which responds to hyperactivated protein kinase C (PKC)a in hepatoma cells. The system could be a useful in hepatoma-specific gene therapy and molecular imaging.

A comparative analysis of changes of student's attitude before and after an international virtual learning class

The purpose of this study was to investigate the effects of international virtual learning classes. For the purpose, the class implemented using multipoint communication system which was constructed high quality video transfer systems on a cross-border infrastructure (gigabit bandwidth) between Japan to South Korea. In order to reveal the effects of the class, a questionnaire was composed of five categories; consciousness to foreign countries, nationality, acquisition of view point, motivation, recognition to the partner country. The results of 2 /spl times/ 2 mixed two-way ANOVA showed differences of characteristics of two countries and changes of students attitude. The results revealed that an international virtual learning class has a possibility to develop and enhance students awareness of humanity and the world. Future implementation will depend on growth and sustenance of the international relationship for a prolonged period.

Investigation of Sea Water Exchange in the Omura Bay by Satellite Remote Sensing Technique and a Test for Confirming Similarity of a Numerical Simulation System

Man-made perturbation on the environment has resulted in many problems such as eutrophication and sedimentation in water bodies. In recent years, domestic sewage and industrial waste water are having a bad infuluence on water quality, especially, estury and closed bay area. Therefore, water quality controlling and monitoring activities are inevitable.We tried to apply satellite remote sensing techniques to investigate the sea water exchange of the Omura Bay and the Sasebo Bay. Maximum likelihood method was used to classify and confirm the exchange condition of sea water bodies. And also, the result are compared with an outcome of numerical simulation methode by workstation computer.

Investigation of Currents in the Omura Bay by Satellite Observation and Its Comparison with Those in a Hydrogeological Model

In recent years, domestic sewage and industrial waste water are having a bad influence on water Quality of the Omura Bay in Nagasaki prefecture. Therefore it is need to monitor water quality and clean up the Omura Bay. In this paper, sea water of satellite observation are classified into water of the Omura Bay and water of the Sasebo Bay by maximum likelihood method, and currents of the Omura Bay are investigated. And the result are compared with currents in a hydrogeological model of the Omura Bay.