2005 Fiscal Year Final Research Report Summary
Cell-cidal effect of the combination therapy of p53 gene under the control of radiation- and hypoxia-sensitized promoter and heavy particle irradiation in glioma
| Project/Area Number |
16591466
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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 |
Cerebral neurosurgery
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| Research Institution | Chiba cancer center research institute |
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Principal Investigator |
KOSHIKAWA Nobuko Chiba Cancer Center Research Institute, Dept. of Pathology, senior investigator, 病理研究部, 主席研究員 (90260249)
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| Co-Investigator(Kenkyū-buntansha) |
TAKENAGA Keizo Chiba Cancer Center Research Institute, Dept. of Chemotherapy, senior investigator, 化学療法研究部, 主席研究員 (80260256)
NOJIMA Kumie Int. space radiation lab, NIRS, Senior investigator, 宇宙放射線防護プロジェクト, 主席研究員 (90218272)
IWADATE Yasuo Chiba Univ., Graduate School of Medicine, Research associate, 大学院・医学研究院・先端応用外科学, 助手 (70272309)
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| Project Period (FY) |
2004 – 2005
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| Keywords | Glioma / high-LET carbon ions / p53 / gene therapy / radiation sensitive promoter / hypoxia sensitive promoter |
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| Research Abstract |
AIM : Malignant gliomas, especially the glioma cells under hypoxic microenvironments, are refractory to conventional radiotherapy and chemotherapy. The aims of this study were to examine the efficacy of combination of radiation/hypoxia dual-sensitive promoter-regulated p53 gene and high-LET radiation for killing glioma cells with mutant p53 under normoxic and hypoxic conditions and to compare the effectiveness as a 'trigger' to activate therapeutic gene expression between high-LET and low-LET radiation. METHODS : The chimeric promoter Egr-HRE was generated by insertion of CArG elements derived from Egr-1 gene and hypoxia response elements(HREs) derived from erythropoietin gene. p53 expression vector was constructed by cloning of the Egr-HRE promoter upstream of p53 gene. After transfecting the plasmid into p53-mutant U373 human glioma cell line, the cells were exposed to hypoxia (0.1% O_2, 24 h) and high-LET (1 Gy) or low-LET radiation (1 Gy). The expression level of p53 and the cell killing effect was determined by Western blotting and colony formation assay, respectively. RESULTS : The results showed that the exposure of the cells to high-LET carbon ions and hypoxia greatly enhanced the expression of p53 and accordingly was most effective in killing the glioma cells. When compared with low-LET radiation, high-LET carbon ions were more effective in enhancing p53 expression and killing the cells. CONCLUSION : The results suggest that the combination of radiation/hypoxia dual promoter-regulated p53 gene and high-LET carbon ions is a promising strategy for effective gene therapy of malignant gliomas and that high-LET radiation is more effective to activate therapeutic gene expression than low-LET radiation.
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