scholarly journals Induction of quinone reductase NQO1 by resveratrol involves antioxidant response element ARE and is accompanied by nuclear translocation of transcription factor Nrf2

2006 ◽  
Vol 20 (4) ◽  
Author(s):  
Tze‐chen Hsieh ◽  
Xiaohua Lu ◽  
Zhirong Wang ◽  
Joseph M Wu
2002 ◽  
Vol 22 (9) ◽  
pp. 2883-2892 ◽  
Author(s):  
Mi-Kyoung Kwak ◽  
Ken Itoh ◽  
Masayuki Yamamoto ◽  
Thomas W. Kensler

ABSTRACT Induction of phase 2 enzymes, which neutralize reactive electrophiles and act as indirect antioxidants, is an important mechanism for protection against carcinogenesis. The transcription factor Nrf2, which binds to the antioxidant response element (ARE) found in the upstream regulatory region of many phase 2 genes, is essential for the induction of these enzymes. We have investigated the effect of the potent enzyme inducer and anticarcinogen 3H-1,2-dithiole-3-thione (D3T) on the fate of Nrf2 in murine keratinocytes. Both total and nuclear Nrf2 levels increased rapidly and persistently after treatment with D3T but could be blocked by cotreatment with cycloheximide. Nrf2 mRNA levels increased ∼2-fold 6 h after D3T treatment. To examine the transcriptional activation of Nrf2 by D3T, the proximal region (1 kb) of the nrf2 promoter was isolated. Deletion and mutagenesis analyses demonstrated that nrf2 promoter-luciferase reporter activity was enhanced by treatment with D3T and that ARE-like sequences were required for this activation. Gel shift assays with nuclear extracts from PE cells indicated that common factors bind to typical AREs and the ARE-like sequences of the nrf2 promoter. Direct binding of Nrf2 to its own promoter was demonstrated by chromatin immunoprecipitation assay. Overexpression of Nrf2 increased the activity of the nrf2 promoter-luciferase reporter, while expression of mutant Nrf2 protein repressed activity. Thus, Nrf2 appears to autoregulate its own expression through an ARE-like element located in the proximal region of its promoter, leading to persistent nuclear accumulation of Nrf2 and protracted induction of phase 2 genes in response to chemopreventive agents.


Blood ◽  
2011 ◽  
Vol 117 (22) ◽  
pp. 5987-5997 ◽  
Author(s):  
Elizabeth R. Macari ◽  
Christopher H. Lowrey

AbstractAlthough hematopoietic stem cell transplantation and gene therapy have the potential to cure β-thalassemia and sickle cell disease, they are not currently available to most people with these diseases. In the near term, pharmacologic induction of fetal hemoglobin (HbF) may offer the best possibility for safe, effective, and widely available therapy. In an effort to define new pathways for targeted drug development for HbF induction, we evaluated the nuclear factor erythroid 2–related factor 2 (NRF2) antioxidant response element signaling pathway. We found that 3 well-known activators of this pathway increased γ-globin mRNA at nontoxic doses in K562 cells. Tert-butylhydroquinone (tBHQ), the most active of these compounds, increased cellular levels and nuclear translocation of NRF2 and binding of NRF2 to the γ-globin promoter. siRNA knockdown of NRF2 inhibited γ-globin induction by tBHQ. When tested in human primary erythroid cells, tBHQ induced NRF2 binding to the γ-globin promoter, increased γ-globin mRNA and HbF, and suppressed β-globin mRNA and HbA, resulting in a > 3-fold increase in the percentage of HbF. These results suggest that drugs that activate the NRF2/antioxidant response element signaling pathway have the potential to induce therapeutic levels of HbF in people with β-hemoglobinopathies.


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