Rhein Inhibits AlkB Repair Enzymes and Sensitizes Cells to Methylated DNA Damage
Rhein Inhibits AlkB Repair Enzymes and Sensitizes Cells to Methylated DNA Damage
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大黄酸抑制 AlkB 修复酶并使细胞对甲基化 DNA 损伤敏感
DOI：
10.1074/jbc.m115.711895
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发表时间：
2016-05-20
影响因子：
4.8
通讯作者：
Yang, Cai-Guang
中科院分区：
文献类型：
--
作者：
Li, Qi;Huang, Yue;Yang, Cai-Guang
AlkB修复酶，包括大肠杆菌AlkB和两种人类同源物ALKBH 2和ALKBH 3，是铁（II）和2-酮戊二酸依赖性双加氧酶，可有效修复N-1-甲基腺嘌呤和N-3-甲基胞嘧啶甲基化DNA损伤。这些酶的小分子抑制剂的开发较少成功。在这里，我们已经确定了先前发现的天然产物大黄酸的特点，并测试了它的能力，抑制AlkB修复酶在体外和敏感细胞的甲基甲烷磺酸，主要产生N-1-甲基腺嘌呤和N-3-甲基胞嘧啶病变。我们对大黄酸抑制机制的研究表明，大黄酸在体外与AlkB修复酶结合，并在体内促进热稳定性。此外，我们已经确定了一个新的结构复杂的大黄酸结合AlkB，这表明大黄酸结合到AlkB的活性位点的不同部分比它结合到脂肪量和肥胖相关蛋白（FTO）。在这些观察结果的支持下，我们提出了AlkB修复酶将成为癌症治疗的有效药理学靶点的假设。
The AlkB repair enzymes, including Escherichia coli AlkB and two human homologues, ALKBH2 and ALKBH3, are iron(II)- and 2-oxoglutarate-dependent dioxygenases that efficiently repair N-1-methyladenine and N-3-methylcytosine methylated DNA damages. The development of small molecule inhibitors of these enzymes has seen less success. Here we have characterized a previously discovered natural product rhein and tested its ability to inhibit AlkB repair enzymes in vitro and to sensitize cells to methyl methane sulfonate that mainly produces N-1-methyladenine and N-3-methylcytosine lesions. Our investigation of the mechanism of rhein inhibition reveals that rhein binds to AlkB repair enzymes in vitro and promotes thermal stability in vivo. In addition, we have determined a new structural complex of rhein bound to AlkB, which shows that rhein binds to a different part of the active site in AlkB than it binds to in fat mass and obesity-associated protein (FTO). With the support of these observations, we put forth the hypothesis that AlkB repair enzymes would be effective pharmacological targets for cancer treatment.