Methylation of the KEAP1 gene promoter region in human colorectal cancer.
Methylation of the KEAP1 gene promoter region in human colorectal cancer.
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DOI：
10.1186/1471-2407-12-66
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发表时间：
2012-02-13
期刊：
影响因子：
3.8
通讯作者：
Saijo Y
中科院分区：
文献类型：
--
作者：
Hanada N;Takahata T;Zhou Q;Ye X;Sun R;Itoh J;Ishiguro A;Kijima H;Mimura J;Itoh K;Fukuda S;Saijo Y
据报道，Keap 1-Nrf 2通路在几种癌症中受损。然而，Keap 1-Nrf 2系统在人类结直肠癌（CRC）中的地位尚未阐明。我们使用结直肠癌（CRC）细胞系和手术标本来研究KEAP 1启动子区域的甲基化状态以及Nrf 2及其下游抗氧化应激基因NQO-1和AKR 1C 1的表达。DNA测序分析表明，所有检测到的突变是同义的，没有氨基酸取代。我们通过亚硫酸氢盐基因组测序和甲基化特异性PCR显示，10个CRC细胞系中有8个在KEAP 1启动子区域具有高甲基化的CpG岛。HT 29细胞与高甲基化KEAP 1启动子导致mRNA和蛋白质表达下降，但未甲基化的Colo 320 DM细胞表现出较高的表达水平。此外，DNA甲基转移酶抑制剂5-Aza-dC与组蛋白去乙酰化酶抑制剂曲马斯他丁A（TSA）联合治疗增加了KEAP 1 mRNA的表达。这些结果表明，KEAP 1启动子甲基化调控其mRNA水平。Nrf 2-抗氧化反应元件（ARE）通路激活剂t-BHQ治疗的时间过程分析显示，24小时内快速反应。HT 29细胞NQO-1和AKR 1C 1 mRNA基础表达水平高于Colo 320 DM细胞。在40例手术CRC标本中，53%的肿瘤组织和25%的正常粘膜中检测到KEAP 1的异常启动子甲基化，表明癌组织显示KEAP 1启动子区域的甲基化增加，对细胞毒性抗癌药物具有保护作用。KEAP 1启动子区域的超甲基化抑制其mRNA表达，并增加CRC细胞和组织中核Nrf 2和下游ARE基因的表达。
The Keap1-Nrf2 pathway has been reported to be impaired in several cancers. However, the status of Keap1-Nrf2 system in human colorectal cancer (CRC) has not been elucidated. We used colorectal cancer (CRC) cell lines and surgical specimens to investigate the methylation status of the KEAP1 promoter region as well as expression of Nrf2 and its downstream antioxidative stress genes, NQO-1 and AKR1C1. DNA sequencing analysis indicated that all mutations detected were synonymous, with no amino acid substitutions. We showed by bisulfite genomic sequencing and methylation-specific PCR that eight of 10 CRC cell lines had hypermethylated CpG islands in the KEAP1 promoter region. HT29 cells with a hypermethylated KEAP1 promoter resulted in decreased mRNA and protein expression but unmethylated Colo320DM cells showed higher expression levels. In addition, treatment with the DNA methyltransferase inhibitor 5-Aza-dC combined with the histone deacetylase inhibitor trichostatin A (TSA) increased KEAP1 mRNA expression. These result suggested that methylation of the KEAP1 promoter regulates its mRNA level. Time course analysis with the Nrf2-antioxidant response element (ARE) pathway activator t-BHQ treatment showed a rapid response within 24 h. HT29 cells had higher basal expression levels of NQO-1 and AKR1C1 mRNA than Colo320DM cells. Aberrant promoter methylation of KEAP1 was detected in 53% of tumor tissues and 25% of normal mucosae from 40 surgical CRC specimens, indicating that cancerous tissue showed increased methylation of the KEAP1 promoter region, conferring a protective effect against cytotoxic anticancer drugs. Hypermethylation of the KEAP1 promoter region suppressed its mRNA expression and increased nuclear Nrf2 and downstream ARE gene expression in CRC cells and tissues.
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影响因子：
254.7
作者：
Jemal, Ahmedin;Siegel, Rebecca;Thun, Michael J.
通讯作者：
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影响因子：
10.5
作者：
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DOI：
10.1016/j.bbrc.2007.08.051
发表时间：
2007-11-03
影响因子：
3.1
作者：
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影响因子：
5.3
作者：
Zhang, DD;Lo, SC;Hannink, M
通讯作者：
Hannink, M
DOI：
10.1073/pnas.172398899
发表时间：
2002-09-03
影响因子：
11.1
作者：
Dinkova-Kostova, AT;Holtzclaw, WD;Talalay, P
通讯作者：
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