配分額 *注記 |
4,160千円 (直接経費: 3,200千円、間接経費: 960千円)
2023年度: 1,170千円 (直接経費: 900千円、間接経費: 270千円)
2022年度: 1,300千円 (直接経費: 1,000千円、間接経費: 300千円)
2021年度: 1,690千円 (直接経費: 1,300千円、間接経費: 390千円)
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研究開始時の研究の概要 |
Cytoglobin (CYGB), an oxygen-binding and reactive oxygen species (ROS) scavenging protein, functions as a tumor suppressor and is inactivated in various cancers. This research aims to (i) examine the protective role of Cygb-overexpression in animal models of liver and pancreas carcinogenesis; (ii) investigate the frequency of DNA methylation of the CYGB promoter in malignant tissues from patients with liver or pancreatic cancers; (iii) targeted demethylation of the CYGB promoter to impair tumor growth. These results will provide the potential therapeutic application of anti-cancer therapy.
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研究実績の概要 |
Forty-two pairs of tumor and adjacent non-tumor tissues from liver cancer patients with chronic hepatitis C virus infection were evaluated for CYGB promoter methylation using Ion GeneStudio S5. Methylation frequency in tumors is significantly higher than that in non-tumor tissues at all 33 CpG sites (P = 1.02E-8) in this region. The mean of methylation index in tumor and non-tumor tissues were 43.8% and 20.5%, respectively. A subset of HCC samples was examined, CYGB mRNA and protein expression in tumor is significantly lower than that in non-tumor tissues (P < 0.05). In vitro, high methylation frequency and no CYGB expression at RNA and protein levels were found in HCC cells (HepG2, Huh7, SNU-387, HLE) and also well-known myofibroblast LX-2 cells. In contrast, almost no methylation in human hepatic stellate cells (both primary and cell line) that correspond to positive CYGB expression. Restoration of CYGB expression was performed in four HCC cell lines treated with 1, 3, 5, and 10 uM 5-aza-2′- deoxycytidine (DAC). Interestingly, DAC treatment time- and dose-dependently restored CYGB expression at both mRNA and protein levels in SNU-387, HLE and Huh7, and at mRNA level in HepG2 cells while DAC did not induce CYGB expression in LX-2. Notably, after inducing CYGB expression in SNU-387, removal of DAC resulted in regressing of CYGB expression at both mRNA and protein levels. DAC is conventional demethylation drug, it may induce demethylation of other gene promoters. Now we are doing targeted demethylation of CYGB by dCas9 and gRNA.
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