| Project/Area Number |
17591285
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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 | Yokohama City University |
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Principal Investigator |
OMURA Motoko Yokohama City University, School of Medicine, Assistant Professor (70244506)
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| Co-Investigator(Kenkyū-buntansha) |
NAKAGAMI Yoshihiro Yokohama City University, School of Medicine, Visiting Researcher (80347301)
INOUE Tomio Yokohama City University, Graduate School of Medicine, Visiting Researcher (80134295)
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| Project Period (FY) |
2005 – 2006
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| Project Status |
Completed (Fiscal Year 2006)
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| Budget Amount *help |
¥1,900,000 (Direct Cost: ¥1,900,000)
Fiscal Year 2006: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 2005: ¥1,200,000 (Direct Cost: ¥1,200,000)
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| Keywords | spheroid siRNA / HIF / VEGF / radiation / VEGF / 放射線増感剤 / si-RNA / スフェロイド / bcl-2 |
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| Research Abstract |
Purpose: Expression of hypoxia-inducible factor (HIP) and vascular endothelial growth factor (VEGF) elevated in hypoxic tumor cells that show resistant to radiation. Therefore, we hypothesized inhibiting HIF and VEGF function may enhance the cytotoxic effects of radiation. To clarify this point, we use small interference RNA (siRNA) to inhibit those gene function and multicellular spheroid as a 3D tumor model.
Materials and methods : Monolayer and spheroids of human lung carcinoma cell SQS, were treated with HIF/VEGF siRNA and/or radiation. Quantitative RT-PCR and western blotting were done to analyze gene expression. Cell toxicity was qualified by colony formation assay.
Results : In spheroid, the expression levels of both HIF and VEGF were stably up-regulated compared with monolayer cells. Treatment with HIF or VEGF siRNA displayed inhibition of those mRNA expressions in both monolayer cells and spheroid. Hypoxic condition apparently induced radiation resistance of monolayer cells and spheroid. HIP siRNA but not VEGF siRNA enhanced radiation effect on monolayer cell under hypoxic condition. Either of HIF or VEGF siRNA did not enhance radiation effect on spheroid either normoxic or hypoxic condition.
Conclusion : Spheroids can be applied for evaluating tumor response to down-regulation gene expression by siRNA. HIF siRNA showed radiation enhancement effect on monolayer cells under hypoxic condition in which radiation resistance of cells were induced.
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