1997 Fiscal Year Final Research Report Summary
Analysis of regulatory mechanism of apoptosis in human neuroblastomas
| Project/Area Number |
08670222
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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 |
Human pathology
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| Research Institution | St.Marianna University School of Medicine |
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Principal Investigator |
KOIZUMI Hirotaka Department of Pathology, St.Marianna University School of Medicine Assistant Professor, 医学部, 講師 (10215155)
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| Co-Investigator(Kenkyū-buntansha) |
UCHIKOSHI Toshiyuki Department of Pathology, St.Marianna University School of Medicine Professor, 医学部, 教授 (60130986)
NAKADA Koonosuke Department of Pediatric Surgery, St.Marianna University School of Medicine Profe, 医学部, 教授 (70081734)
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| Project Period (FY) |
1996 – 1997
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| Keywords | Neuroblastoma / Regression / Apoptosis / Fas / Fas ligand |
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| Research Abstract |
Objective To understand the mechanism of apoptosis in neuroblastomas (NBs) in vivo, we investigated expression profiles of Fas, Fas ligand (FasL) and caspase-3 in primary NB tissues.
Methods Immunoperoxidase staining for Fas and FasL/caspase-3 was performed in paraffin sections of 32 and 46 tumor specimens, respectively, using tyramide signal amplification. Tissue lysates of ten NBs were analyzed in immunoblotting for Fas, FasL and caspase-3 expression and in the substrate hydrolytic assay using Ac-Asp-Glu-Val-Asp (DEVD) -MCA for caspase-3-like activity. In the tumors showing caspase-3-like activity, inhibition assay using Ac-DEVD-H peptide was further carried out.
Results Eighty-eight percent of NBs exhibited no or only faint Fas immunostaining, although-70% of them did moderate to strong immunoreactivities for FasL and caspase-3. In the few NBs showing moderate Fas immunoreactivity, the protein expressing cells did not exist nearby apoptotic foci. Consistent with the immunostaining results, immunoblot analyzes showed no Fas expression in all tested tumors, whereas they expressed FasL and caspase-3 at various degrees. Four of ten NBs showed significant caspase-3-like activities that were markedly suppressed by the caspase-3 specific inhibitor Ac-DEVD-H (-90% inhibition).
Conclusion NBs hardly express Fas, but considerably caspase-3, which can lead to DNA fragmentation, in, at least in part, activated form, suggesting that non-Fas-mediated pathway (s), such as that involving p53 and/or Bcl-2 family proteins, may regulate apoptosis in these tumors.
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