| Project/Area Number |
15590727
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Circulatory organs internal medicine
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| Research Institution | Tokyo Medical and Dental University |
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Principal Investigator |
ADACHI Susumu Tokyo Medical and Dental University Hospital, Faculty of Medicine, Lecturer, 医学部・附属病院, 講師 (20343155)
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| Co-Investigator(Kenkyū-buntansha) |
ITO Hiroshi Akita University, School of Medicine, Professor, 医学部, 教授 (10232464)
ISOBE Mitsuaki Tokyo Medical and Dental University, School of Medicine, Professor, 大学院・医歯学総合研究科, 教授 (80176263)
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| Project Period (FY) |
2003 – 2004
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| Project Status |
Completed (Fiscal Year 2004)
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| Budget Amount *help |
¥2,800,000 (Direct Cost: ¥2,800,000)
Fiscal Year 2004: ¥1,300,000 (Direct Cost: ¥1,300,000)
Fiscal Year 2003: ¥1,500,000 (Direct Cost: ¥1,500,000)
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| Keywords | cardiomyocytes / apoptosis / nitricoxide / cyclin / caspase / S-nitrosylation / 酸化窒素 / サイクリンA |
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| Research Abstract |
Doxorubicin (Dox) is an anticancer agent which has the side effect of cardiac toxicity. However, the precise molecular mechanism of doxorubicin-induced myocardial apoptosis is still unknown. We have previously reported that cyclin A/cdk2 kinase activity, which is one of the cell cycle regulators, is mediated hypoxia-induced apoptosis in cardiomyocytes. Because apoptosis typically begins in the cytoplasm in the proliferating cells, we tested the hypothesis that the subcellular localization of cyclin A determines the apoptotic fate. Primary rat cardiomyocytes were exposed to doxorubicin and increased apoptosis dose-dependently (10-5 to 10-7M) evaluated by TUNEL method and the number of viable cells. The cyclin A protein level assessed by immunoblot analysis accumulated with a maximum response after 6 hours treatment in cardiomyocytes. Also, doxorubicin increased in the activity of cyclin A-and cdk2-associated kinase by histone-H1 kinase assay. By immnohistochemistry, cyclin A was cytoplasm in cardiomyocytes, however, cyclin A was nuclear in proliferating condition of fibroblasts. To test whether the cyclin A-associated kinase was the effector for apoptosis, cardiomyocytes were infected by dominant-negative cdk2 adenovirus (dncdk2). The apoptosis by doxorubicin(10-6M) was significantly reduced (cont. 4.8± 1.8%, Dox. 46.2±4.0%, Dox+dncdk2 25.8±6.0%), suggesting that cyclin A/cdk2 kinase activity play significant roles in the doxorubicin induced apoptosis. In conclusion, these findings confirm that the activation of cyclin A in cytoplasm mediates doxorubicin-induced apoptosis in cardiomyocytes.
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