Induction of the Antioxidant Response by the Transcription Factor NRF2 Increases Bioactivation of the Mutagenic Air Pollutant 3-Nitrobenzanthrone in Human Lung Cells
Induction of the Antioxidant Response by the Transcription Factor NRF2 Increases Bioactivation of the Mutagenic Air Pollutant 3-Nitrobenzanthrone in Human Lung Cells
复制标题
DOI：
10.1021/acs.chemrestox.9b00399
复制
发表时间：
2019-12-01
影响因子：
4.1
通讯作者：
Penning, Trevor M.
中科院分区：
文献类型：
--
作者：
Murray, Jessica R.;de la Vega, Laureano;Penning, Trevor M.
3-硝基苯蒽酮（3-NBA）是柴油机尾气中存在的一种疑似人类致癌物。它需要通过硝基还原进行代谢活化，以形成DNA加合物并促进诱变。我们已经确定，人醛酮还原酶（AKR1C1 - 1C3）和NAD（P）-H：醌氧化还原酶1（NQO1）对肺上皮细胞系中3-NBA的硝基还原作用相同，并共同代表50%的硝基还原酶活性。编码这些酶的基因由转录因子NF-E2 p45相关因子2（NRF 2）诱导，这增加了NRF 2活化加剧3-NBA变性的可能性。由于A549细胞具有组成型活性NRF 2，我们检查了通过CRISPR-Cas9基因编辑的杂合（NRF 2-Het）和纯合NRF 2敲除（NRF 2-KO）对3-NBA活化的影响。为了评估NRF2介导的基因诱导是否增加3-NBA激活，我们研究了NRF2激活剂在永生化人支气管上皮细胞（HBEC3-KT）中的作用。通过qPCR、免疫印迹和酶活性测定证实了通过NRF2敲除或使用NRF2激活剂引起的AKR1C1 - 1C3和NQO1表达的变化。我们观察到A549 NRF 2 KO细胞系中3-NBA活化降低（A549 NRF 2-Het细胞中降低53%，A549 NRF 2-KO细胞中降低82%），HBEC 3-KT细胞中由于NRF 2活化剂，3-NBA生物活化增加40 - 60%。总之，我们的数据表明，转录因子NRF2的激活加剧了致癌物质代谢后暴露于柴油机废气，这可能会导致增加3-NBA衍生的DNA加合物。
3-Nitrobenzanthrone (3-NBA) is a suspected human carcinogen present in diesel exhaust. It requires metabolic activation via nitroreduction in order to form DNA adducts and promote mutagenesis. We have determined that human aldo-keto reductases (AKR1C1-1C3) and NAD(P)-H:quinone oxidoreductase 1 (NQO1) contribute equally to the nitroreduction of 3-NBA in lung epithelial cell lines and collectively represent 50% of the nitroreductase activity. The genes encoding these enzymes are induced by the transcription factor NF-E2 p45-related factor 2 (NRF2), which raises the possibility that NRF2 activation exacerbates 3-NBA toxification. Since A549 cells possess constitutively active NRF2, we examined the effect of heterozygous (NRF2-Het) and homozygous NRF2 knockout (NRF2-KO) by CRISPR-Cas9 gene editing on the activation of 3-NBA. To evaluate whether NRF2-mediated gene induction increases 3-NBA activation, we examined the effects of NRF2 activators in immortalized human bronchial epithelial cells (HBEC3-KT). Changes in AKR1C1-1C3 and NQO1 expression by NRF2 knockout or use of NRF2 activators were confirmed by qPCR, immunoblots, and enzyme activity assays. We observed decreases in 3-NBA activation in the A549 NRF2 KO cell lines (53% reduction in A549 NRF2-Het cells and 82% reduction in A549 NRF2-KO cells) and 40-60% increases in 3-NBA bioactivation due to NRF2 activators in HBEC3-KT cells. Together, our data suggest that activation of the transcription factor NRF2 exacerbates carcinogen metabolism following exposure to diesel exhaust which may lead to an increase in 3-NBA-derived DNA adducts.