| Co-Investigator(Kenkyū-buntansha) |
KOIZUMI Hirotaka St.Marianna University, Dept.of Pathology, Assistant Professor, 医学部, 講師 (10215155)
TAKAKUWA Toshifumi St.Marianna University, Dept.of Pathology, Associate Professor, 医学部, 助教授 (90121201)
WAKISAKA Munechika St.Marianna University, 3rd Dept.of Surgery, Assistant Doctor, 医学部, 助手 (30267596)
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| Budget Amount *help |
¥2,300,000 (Direct Cost: ¥2,300,000)
Fiscal Year 1997: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 1996: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 1995: ¥1,000,000 (Direct Cost: ¥1,000,000)
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| Research Abstract |
We investigated to understand the occurrence of apoptosis, and the mechanism of the occurrence, if it may occur, in neuroblasatoma (NB), demonstrating some apoptosis-regulatory proteins in the neuroblastoma tissue. First, we demonstrated apoptosis in NB by means of histopathology and immunohistochemistry (a light microscopic observation w/wo immunostaining method and an electron microscopic observation), and DNA fragmentation analyzes. Second, we investigated expressions of bcl-2, Fas antigen in neuroblastoma tissue, and third, investigated expression profiles of Fas, Fas ligand (FasL) and caspase-3 in primary NB tissues using immunohistochemical analysis. Histologically, a number of tumor cells showed typical apoptotic changes. These cells coincided closely with the so-celled karyorrhectic cells. An electrophoretic DNA ladder was revealed four of six tumors, and DNA fragmentation was detected in situ by terminal deoxytransferase-mediated nick end-labeling in 26 of 35 tumor specimens (
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74%). The labeled cell counts ranged from 5 to 62 per 5,000 tumor cells (mean+-SD : 15.0+-14.5). Immunoperoxidase staining revealed that an apoptosis-suppressing protein, bcl-2, was expressed abundantly in advanced-stage tumors, whereas it was absent from karyorrhectic-apoptotic cells. Several tumors with the potential for spontaneous regression were bcl-2-deficient. By immunoperoxidase staining, 88% of NBs exhibited no or only faint Fas immunostaining, although over 70% of them did moderate to strong immunoreactivities for FasL and caspase-3. Immunoblot analyzes showed no Fas expression in all tested tumors, whereas they expressed FasL and caspase-3 in various degrees. NB tissues showing significant caspase-3-like activities were markedely suppressed by the caspase-3 specific inhibitor Ac-DEVD-H.
Our results provide ; 1) exact evidence of apoptosis in NB,2) bcl-2 may exist for playing a role in its regulatory mechanism, 3) There are non-Fas mediated pathway (s) may regulate apoptosis in the NBs.4) Some NB tumors may regress spontaneously by in part the apoptosis of the tumor cells. Prognoses of those patients with spontaneous tumor regression are quite favorable. Less
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