The Nrf2 transcription factor is a positive regulator of myeloid differentiation of acute myeloid leukemia cells
The Nrf2 transcription factor is a positive regulator of myeloid differentiation of acute myeloid leukemia cells
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DOI：
10.4161/cbt.11.3.14098
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发表时间：
2011-02-01
影响因子：
3.6
通讯作者：
Danilenko, Michael
中科院分区：
文献类型：
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作者：
Bobilev, Irene;Novik, Victoria;Danilenko, Michael
1α，25-二羟基维生素D3(1，25D)是一种强大的分化药物，具有治疗急性髓系白血病(AML)的潜力，但在药理活性剂量下会导致严重的高血钙症。我们先前已经证明，迷迭香植物中的多酚抗氧化剂鼠尾草酸(CA)显著增强低浓度1，25D诱导的人AML细胞系的分化。在这里，我们在AML患者的原代白血病细胞中展示了类似的对1，25D/CA组合的增强分化反应，并以U937人单核细胞白血病细胞为模型，确定了Nrf2/抗氧化剂反应元件(Nrf2/ARE)通路在这些作用中的作用。CA强烈反式激活ARE-荧光素酶报告基因，诱导ARE反应基因NADP(H)苯醌氧化还原酶和γ-谷氨酰半胱氨酸合成酶重亚单位，并提高细胞谷胱甘肽水平。有趣的是，1，25D增强了CA对这些活性的影响。稳定的野生型(Wt)Nrf2表达增强，而显性-阴性(DN)Nrf2表达抑制1，25D/CA组合诱导的分化，令人惊讶的是，单独1，25D诱导分化。这些相反的作用与维生素D受体和维甲酸X受体-α蛋白水平的相应增加或减少以及维生素D反应元件的反式激活有关。转染wtNrf2和dnNrf2的细胞在AP-1家族蛋白(c-Jun和ATF2)水平和AP-1转录活性方面也显示出相反的变化。AP-1诱骗寡核苷酸可显著抑制wtNrf2细胞的分化，提示Nrf2的促分化作用是由功能性AP-1介导的。我们的研究结果表明，Nrf2/ARE通路在1，25D和一种植物多酚协同诱导髓系白血病细胞分化中起重要作用。
1 alpha, 25-dihydroxyvitamin D3 (1,25D) is a powerful differentiation agent, which has potential for treatment of acute myeloid leukemia (AML), but induces severe hypercalcemia at pharmacologically active doses. We have previously shown that carnosic acid (CA), the polyphenolic antioxidant from rosemary plant, markedly potentiates differentiation induced by low concentrations of 1,25D in human AML cell lines. Here, we demonstrated similar enhanced differentiation responses to the 1,25D/CA combination in primary leukemic cells derived from patients with AML, and determined the role of the Nrf2/antioxidant response element (Nrf2/ARE) pathway in these effects using U937 human monoblastic leukemia cells as the model. CA strongly transactivated the ARE-luciferase reporter gene, induced the ARE-responsive genes, NADP(H)quinone oxidoreductase and the gamma-glutamylcysteine synthetase heavy subunit, and elevated cellular glutathione levels. Interestingly, 1,25D potentiated the effects of CA on these activities. Stable transfection of wild-type (wt) Nrf2 resulted in the enhancement, while transfection of dominant-negative (dn) Nrf2 produced suppression of differentiation induced by the 1,25D/CA combination and, surprisingly, by 1,25D alone. These opposite effects were associated with a corresponding increase or decrease in vitamin D receptor and retinoid X receptor-alpha protein levels, and in vitamin D responsive element transactivation. Cells transfected with wtNrf2 and dnNrf2 also displayed opposing changes in the levels of the AP-1 family proteins (c-Jun and ATF2) and AP-1 transcriptional activity. Pretreatment with AP-1 decoy oligodeoxynucleotide markedly attenuated the differentiation in wtNrf2-transfected cells, suggesting that the pro-differentiation action of Nrf2 is mediated by functional AP-1. Our findings suggest that the Nrf2/ARE pathway plays an important part in the cooperative induction of myeloid leukemia cell differentiation by 1,25D and a plant polyphenol.