2005 Fiscal Year Final Research Report Summary
Alterations of the apoptosis signaling pathways in oncogenesis of odontogenic epithelium
| Project/Area Number |
16591881
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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 |
Pathobiological dentistry/Dental radiology
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| Research Institution | Tohoku University |
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Principal Investigator |
KUMAMOTO Hiroyuki Tohoku University, Graduate School of Dentistry, Research Assistant, 大学院・歯学研究科, 助手 (70215028)
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| Project Period (FY) |
2004 – 2005
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| Keywords | odontogenic tumor / apoptosis / signal transduction |
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| Research Abstract |
To clarify the possible roles of the apoptosis signaling pathways in oncogenesis of odontogenic epithelium, expression of death receptor- and mitochondria-mediated pathway signaling molecules was analyzed in ameloblastomas and malignancy ameloblastomas as well as in tooth germs.
1.Death receptor-mediated apoptosis signaling molecules : Representative death receptors, TNFRI and TRAIL-R1,2, and their downstream apoptosis initiator, caspase-8, were examined in tooth germs and benign and malignant ameloblastomas by RT-PCR and immunohistochemistry. Expression of TNFRI and TRAIL-R1,2 was detected in both normal and neoplastic odontogenic tissues, and they were distributed widely in epithelial components. In contrast, expression of caspase-8 was detected in a few cases of ameloblastomas, and its distribution is limited.
2.Mitochondria-mediated apoptosis signaling molecule : Representative mitochondrial apoptotic pathway signaling molecules, cytochrome c, APAF-1, and caspase-9, were examined in tooth germs and benign and malignant ameloblastomas by RT-PCR and immunohistochemistry. Expression of cytochrome c, APAF-1, and caspase-9 was detected in both normal and neoplastic odontogenic tissues. Cytochrome c distribution was evident in odontogenic epithelial cells neighboring the basement membrane, whereas APAF-1 and caspase-9 were expressed in most odontogenic epithelial cells. Immunoreactivity for cytochrome c in tooth germs was slightly weaker than that in ameloblastomas and malignant ameloblastomas.
3.Conclusions : The mitochondria-mediated apoptotic pathway has a role in apoptotic cell death of normal and neoplastic odontogenic epithelium, rather than the death receptor-mediated apoptotic pathway. Alterations of these apoptosis signaling molecules might be involved in oncogenesis of odontogenic epithelium.
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