2003 Fiscal Year Final Research Report Summary
p53-Independent ceramide formation in human glioma cells during gamma-radiation-induced apoptosis.
| Project/Area Number |
14370429
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Cerebral neurosurgery
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| Research Institution | GIFU UNIVERSITY |
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Principal Investigator |
IWAMA Toru Gifu University, Neurosurgery, Professor, 医学部附属病院, 教授 (20303498)
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| Co-Investigator(Kenkyū-buntansha) |
YOSHIMURA Sinichi Gifu University, Neurosurgery, Lecturer, 医学部, 助手 (40240353)
SHINODA Jyn Gifu University, Neurosurgery, Assistant Professor, 医学部, 助教授 (50273131)
SAKAI Noboru Gifu University, Neurosurgery, Professor, 医学部, 教授 (10021487)
BANNO Yoshiko Gifu University, Cell Signaling, Assistant Professor, 医学部, 助教授 (50116852)
NAKASHIMA Shigeru Gifu University, Cell Signaling, Professor, 医学部, 教授 (60188935)
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| Project Period (FY) |
2002 – 2003
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| Keywords | apoptosis / p53 / glima / radiation / セラミド |
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| Research Abstract |
Although the p53 tumor-suppressor gene product plays a critical role in apoptotic cell death induced by DNA-damaging chemotherapeutic agents, human glioma cells with functional p53 were more resistant to gamma-radiation than those with mutant p53. U-87 MG cells with wild-type p53 were resistant to gamma-radiation. U87-W E6 cells that lost functional p53, by the expression of type 16 human papillomavirus E6 oncoprotein, became susceptible to radiation-induced apoptosis. The formation of ceramide by acid sphingomyelinase (A-SMase), but not by neutral sphingomyelinase, was associated with p53-independent apoptosis SR33557 (2-isopropyl-1-(4-[3-N-methyl-N-(3,4-dimethoxybphenethyl) amino]propyloxy)benzene-sulfonyl) indolizine, an inhibitor of A-SMase, suppressed radiation-induced apoptotic cell death. In contrast, radiation-induced A-Smase activation was blocked in glioma cells with endogenous functional p53. The expression of acid ceramidase was induced by gamma-radiation, and was more evident in cells with functional p53. N-oleoylethanolamine, which is known to inhibit ceramidase activity, unexpectedly downregulated acid ceramidase and accelerated radiation-induced apoptosis in U87-W E6 cells. Moreover, cells with functional p53 could be sensitized to gamma-radiation by N-oleoylethanolamine, which suppressed radiation-induced acid ceramidase expression and then enhanced ceramide formation. Sensitization to gamma-radiation was also observed in U87-MG cells depleted of functional p53 by retroviral expression of small interfering RNA. These results indicate that ceramide may function as a mediator of p53.-independent apoptosis in human glioma cells in response to gamma-radiation, and suggest that p53-dependent expression of acid ceramidase and blockage of A-SMase activation play pivotal roles in protection from gamma-radiation of cells with endogenous functional p53.
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Research Products
(8 results)
