| Project/Area Number |
14570889
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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 |
Radiation science
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| Research Institution | Kawasaki Medical School |
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Principal Investigator |
HIRATSUKA Junichi Kawasaki Medical School, medical dep., assistant professor, 医学部, 助教授 (30192298)
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| Co-Investigator(Kenkyū-buntansha) |
KONDO Hirofumi Bio-Research Inc., Active director/senior researcher, 代表取締役/主任研究員(研究職)
OTUSKI Takemi Kawasaki Medical School, medical dep., professor, 医学部, 教授 (40160551)
近藤 浩文 (株)バイオリサーチ, 代表取締役・主任研究員(研究職)
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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 |
¥2,700,000 (Direct Cost: ¥2,700,000)
Fiscal Year 2003: ¥1,300,000 (Direct Cost: ¥1,300,000)
Fiscal Year 2002: ¥1,400,000 (Direct Cost: ¥1,400,000)
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| Keywords | malignant melanoma / radiation resistance / Elkind recovery / melanogenesis / tyrosinase related protein-2 / cell cycle / homologous recombinational repair / RAD 51 family |
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| Research Abstract |
There are several reports that TRP-2 plays a critical role in the resistance against the DNA damaging agents such as CDDP and the ultraviolet irradiation. In our fundamental experiment, it has become clear that there is a close correlation between the melanin producing activity and the X-ray radiation resistance of the melanoma cells. We reviewed the relation between the melanogenesis and the resistance to X-ray irradiation using human melanoma cell lines.
IDT-10 cells which were transfected the human TRP-2 expression plasmid into Ihara cells, highly pigmented human melanoma cell line, were used in this study, there was not much difference in cell growth between Ihara cells and IDT-10 cells. The expression levels of TRP-2 protein and the amounts of total melanin in IDT-10 cells were 2.8 and 1.5 times as high as those in Ihara cells, respectively.
In the clonogenic assay, the enhancement of "Elkind recovery" was observed in IDT-10 cells, and the survival rates of IDT-10 cells were higher than those of Ihara cells after irradiation with 4 MV X-rays. Elkind recovery is the result of the repair of sublethal damage that is due to DNA double-strand breaks(DSBs) repair mediated by homologous recombination in late S-G2 phase. Ihara and IDT-10 cells were tested with flow cytometry, and significant accumulation of cells in the S-G2 phase was observed in IDT-10 cells until 64 h after 8Gy irradiation. In addition, IDT-10 cells showed a significantly higher level of ERK phosphorylation relative to Ihara cells after irradiation by Western analysis.
These results suggested that radiation resistance associated with TRP-2 expression in melanoma was due to cell cycle regulation by active-ERK and due to increase DNA DSBs repair capacity in late S-G2 phase.
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