| Project/Area Number |
14580804
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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 |
Laboratory animal science
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| Research Institution | Japanese Foundation for Cancer Research |
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Principal Investigator |
KOBAYASHI Toshiyuki Japanese Foundation for Cancer Research, Cancer Institute, Department of Pathology, Associate, 癌研究所・実験病理部, 研究員 (40260070)
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| Project Period (FY) |
2002 – 2003
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| Project Status |
Completed (Fiscal Year 2003)
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| Budget Amount *help |
¥3,500,000 (Direct Cost: ¥3,500,000)
Fiscal Year 2003: ¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 2002: ¥2,500,000 (Direct Cost: ¥2,500,000)
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| Keywords | Tsc2 / tuberin / knockout mouse / transgenic Eker rat / renal tumor / tuberous sclerosis / S6 kinase / Erc / mesothelin |
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| Research Abstract |
Expression vector for Tsc2 (tuberous sclerosis 2 gene) cDNA was introduced in Tsc2-deficient mouse renal tumor (RT) cell line (MKOC1.-277) and stable lines expressing tuberin (T2 cells) were established. Phosphorylation of p70 S6 kinase (S6K) was suppressed in T2 cells as compared with control cell lines with empty vector. Tumorigenic potential of RC cells in the nude mouse was suppressed by tuberin expression. Administration of rapamycin, a mTOR inhibitor, also blocked tumorigenesis of RC cells. These results suggest that mTOR〜S6K pathway has some role in tumorigenesis caused by Tsc2-mutation. Interestingly, expression of Erc mRNA (mesothelin gene homologue) was also suppressed in T2 cells. In contrast, rapamycin treatment of parental MKOC1-277 cells did not change expression level of Erc mRNA. These results suggest that Erc is regulated by downstream signaling pathway of tuberin, which is independent of mTOR〜S6K. This novel tuberin-regulated pathway may be a new candidate for therapeutic molecular target for tuberous sclerosis. To search for pathways regulating Erc expression, Hela cells were treated with various stimuli or chemical inhibitors and activators of signal transduction pathways and analyzed by northern and western blot analyses. In the case of serum starvation, amino-terminal half of Erc protein was increased, probably by protease-mediated cleavage. Thus, expression and function of Erc protein may be regulated by post-translational level in relation with cell growth. In this study, search for candidates of tuberin-binding protein was also performed. Gamma-adaptin and myomegalin were identified by two-hybrid analysis using carboxy-terminal region of tuberin containing Rapt-GAP homology domain as a bait.
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