Grant-in-Aid for international Scientific Research
|Allocation Type||Single-year Grants |
|Research Institution||University of Tokushima |
YOSHIMURA Tetsuro Institute for Enzyme Research, University of Tokushima, 酵素科学研究センター, 助教授 (30035472)
DEBS Robert J. Cancer Research Institute, University of California, 医学部癌研究所, 主任研究員
HONG Keelung Cancer Research Institute, University of California, 医学部癌研究所, 主任研究員
PAPAHADJOPOU デメトリオス カリフォルニア大学, 医学部癌研究所, 教授
MAEZAWA Shigenori Institute for Enzyme Research, University of Tokushima, 酵素科学研究センター, 助手 (70173698)
SONE Saburo 3rd Department of Internal Medicine, University of Tokushima, 医学部附属病院, 講師 (40145024)
PAPAHADJOPOULOS Demetrio Cancer Research Institute, University of California
|Project Period (FY)
1990 – 1991
Completed (Fiscal Year 1991)
|Budget Amount *help
¥4,400,000 (Direct Cost: ¥4,400,000)
Fiscal Year 1991: ¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 1990: ¥2,400,000 (Direct Cost: ¥2,400,000)
|Keywords||Antitumor Cytokines / Liposome / Tumor Cells / Macrophage / Cytotoxic Effect / Intracellular Behavior / Fluorescence Microphotometry / Membrane Fusion. / 顕微蛍光法|
Antitumor cytokines have cytotoxic effects on tumor cells. However, their exact mechanisms of action are still unknown. Recently, Dr. Papahadjopoulos' group in Cancer Research Institute of University of California developed a method to detect the intracellular behavior of substances by introducing fluorescent probe-encapsulated. liposomes into cells. To elucidate the mechanisms of action of cytokines, therefore, we applied this method and collaborated with his group.
In the present study, we attempted to construct this system using fluorescence microphotometer in our institute, apply the constructed system for detection of intracellular behaviors of liposome-encapsulated antitumor cytokines, and examine the relation between their behaviors and cytotoxic effects. We also attempted to continue our joint research project on the protein- and peptide-induced membrane fusion.
Results are as follows.
1. We discussed with them the relationship between the membrane actions and cytotoxic effects of
antitumor cytokines and the role of membrane phosphatidylserine in their actions as well as the molecular mechanism of membrane fusion induced by proteins, and published some papers.
2. We constructed a system to detect and analyze kinetically endocytosis and intracellular fate of liposomes using fluorescence microphotometer and tumor cell lines and macrophage cells.
3. Using this system, we analyzed endocytosis and intracellular fate of liposome-encapsulated immunoglobulin and transferrin in macrophage cells, and found that immunoglobulin was delivered to lysosomes but transferrin was recycled to plasma membranes.
4. Using this system, we also analyzed endocytosis and intracellular fate of liposome-encapsulated antitumor cytokines in tumor and macrophage cells, and found that cytokines may act on endosome membranes after delivery and that their actions are related to the cytotoxic effect of macrophage cells activated by liposome-encapsulated cytokines.
5. We-almost elucidated the molecular mechanism of clathrin-induced membrane fusion by our findings on the critical events involved in fusion, the sequence of these events, and the fusogenic domain of the clathrin molecule.
6. We synthesized an amphiphilic model peptide, examined the relations between binding ability to membranes, helicity and fusogenicity of this peptide, and found that the fusogenicity is correlated with the hydrophobicity rather than the amphiphilicity of the peptide. Less