| Project/Area Number |
17591911
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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 |
Morphological basic dentistry
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| Research Institution | Okayama University |
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Principal Investigator |
MEHMET Gunduz Okayama University, Oral Pathology and Medicine, Assistant Professor, 大学院医歯薬学総合研究科, 助手 (70333507)
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| Co-Investigator(Kenkyū-buntansha) |
NAGAI Noriyuki Okayama University, Oral Pathology and Medicine, Professor, 大学院医歯薬学総合研究科, 教授 (90085770)
NAGATSUKA Hitoshi Okayama University, Oral Pathology and Medicine, Associate Professor, 大学院医歯薬学総合研究科, 助教授 (70237535)
TAMAMURA Ryo Okayama University, Oral Pathology and Medicine, Assistant Professor, 大学院医歯薬学総合研究科, 助手 (00403494)
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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 |
¥3,400,000 (Direct Cost: ¥3,400,000)
Fiscal Year 2006: ¥1,400,000 (Direct Cost: ¥1,400,000)
Fiscal Year 2005: ¥2,000,000 (Direct Cost: ¥2,000,000)
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| Keywords | Oral cancer / ING family / Splicing variant / p53 / Apoptosis / Tumor suppressor / Methylation |
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| Research Abstract |
1. Oral cancer occurs through inactivation of multiple tumor suppressor genes and activation of oncogenes. In this research, we examined the functions of the ING family members genes ING1b, ING1c and ING3, which we previously identified. mRNA expression analysis of splicing variants ING1b and ING1c showed 30% and 58% decrease in tumor samples as compared with the matched normal counterparts. On the other hand, ING3 mRNA was down-regulated in 50% of cancer samples. Restriction endonuclease-based methylation analysis demonstrated 51% methylation of ING1b variant, while it was not detected in ING1c. These results suggested that different splicing variants and members have various role and mechanisms in oral cancer.
2. Flag-tagged expression vectors of ING1b, ING1c and ING3 were constructed for in vitro functional analysis. Each of these vectors alone and combination with p53 expression vectors were transfected into the cell lines of HEK293, SCCKN, HSC3, HSC3 and cell proliferation and apop
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tosis assay were performed. These assays showed that INGlc-p53 combination gave a better cell inhibitory effect. Each gene and combination with p53 also resulted in apoptotic changes.
3. To examine the response of the ING family and proapoptotic as well as antiapoptotic genes to the cytotoxic drugs, we treated the cells with 5-FU, Cisplatin and Etoposide and mRNA expressions of ING1lb, ING1c, ING3, Bax and Bc1-2 were checked by quantitative RT-PCR. These experiments showed different reactions with various drugs in each cell line, suggesting that signaling of each variant and member has different mechanism.
4. We also examined ING3 mRNA expression in over 70 cancer samples and compared with clinicopathological variables. This study demonstrated ING3 mRNA value as a possible prognostic marker. The samples with ING3 down-regulation had bad prognosis with a 40% survival rate as compared to 60% survival in normal ING3 mRNA expression. Future studies will include suppression work of each ING family member by siRNA and examination of the results in animal experiments. Identification of all networks of ING family will lead to development of novel molecular therapies In various cancer types including oral cancer. Less
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