Shah N M, Zaitseva L, Bowles K M, MacEwan D J, Rushworth S A
1] Department of Molecular Haematology, Norwich Medical School, University of East Anglia, Norwich Research Park, Norwich, UK [2] Department of Molecular and Clinical Pharmacology, Institute of Translational Medicine, University of Liverpool, Liverpool, UK.
Department of Molecular Haematology, Norwich Medical School, University of East Anglia, Norwich Research Park, Norwich, UK.
Cell Death Differ. 2015 Apr;22(4):654-64. doi: 10.1038/cdd.2014.152. Epub 2014 Oct 17.
Transcription factor NRF2 is an important regulator of oxidative stress. It is involved in cancer progression, and has abnormal constitutive expression in acute myeloid leukaemia (AML). Posttranscriptional regulation by microRNAs (miRNAs) can affect the malignant phenotype of AML cells. In this study, we identified and characterised NRF2-regulated miRNAs in AML. An miRNA array identified miRNA expression level changes in response to NRF2 knockdown in AML cells. Further analysis of miRNAs concomitantly regulated by knockdown of the NRF2 inhibitor KEAP1 revealed the major candidate NRF2-mediated miRNAs in AML. We identified miR-125B to be upregulated and miR-29B to be downregulated by NRF2 in AML. Subsequent bioinformatic analysis identified putative NRF2 binding sites upstream of the miR-125B1 coding region and downstream of the mir-29B1 coding region. Chromatin immunoprecipitation analyses showed that NRF2 binds to these antioxidant response elements (AREs) located in the 5' untranslated regions of miR-125B and miR-29B. Finally, primary AML samples transfected with anti-miR-125B antagomiR or miR-29B mimic showed increased cell death responsiveness either alone or co-treated with standard AML chemotherapy. In summary, we find that NRF2 regulation of miR-125B and miR-29B acts to promote leukaemic cell survival, and their manipulation enhances AML responsiveness towards cytotoxic chemotherapeutics.
转录因子NRF2是氧化应激的重要调节因子。它参与癌症进展，在急性髓系白血病（AML）中存在异常的组成型表达。微小RNA（miRNA）的转录后调控可影响AML细胞的恶性表型。在本研究中，我们鉴定并表征了AML中NRF2调控的miRNA。miRNA阵列鉴定了AML细胞中响应NRF2敲低的miRNA表达水平变化。对NRF2抑制剂KEAP1敲低同时调控的miRNA进行进一步分析，揭示了AML中主要的NRF2介导的候选miRNA。我们发现AML中NRF2上调miR-125B并下调miR-29B。随后的生物信息学分析确定了miR-125B1编码区上游和mir-29B1编码区下游的假定NRF2结合位点。染色质免疫沉淀分析表明，NRF2与位于miR-125B和miR-29B 5'非翻译区的这些抗氧化反应元件（ARE）结合。最后，用抗miR-125B抗miR或miR-29B模拟物转染的原发性AML样本单独或与标准AML化疗联合处理时，显示出细胞死亡反应性增加。总之，我们发现NRF2对miR-125B和miR-29B的调控作用是促进白血病细胞存活，而对它们的调控增强了AML对细胞毒性化疗药物的反应性。
