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Wu Z, Uchi H, Morino-Koga S, Shi W, Furue M. Z-ligustilide ameliorated ultraviolet B-induced oxidative stress and inflammatory cytokine production in human keratinocytes through upregulation of Nrf2/HO-1 and suppression of NF-κB pathway. Exp Dermatol 2015; 24:703-8. [DOI: 10.1111/exd.12758] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/07/2015] [Indexed: 12/22/2022]
Affiliation(s)
- Zhouwei Wu
- Department of Dermatology; Shanghai First People's Hospital; Shanghai Jiaotong University; Shanghai China
- Department of Dermatology; Graduate School of Medical Sciences; Kyushu University; Fukuoka Japan
| | - Hiroshi Uchi
- Department of Dermatology; Graduate School of Medical Sciences; Kyushu University; Fukuoka Japan
| | - Saori Morino-Koga
- Department of Dermatology; Graduate School of Medical Sciences; Kyushu University; Fukuoka Japan
| | - Weimin Shi
- Department of Dermatology; Shanghai First People's Hospital; Shanghai Jiaotong University; Shanghai China
| | - Masutaka Furue
- Department of Dermatology; Graduate School of Medical Sciences; Kyushu University; Fukuoka Japan
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202
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YAN YUFENG, YANG WENJIE, XU QIANG, CHEN HEPING, HUANG XIAOSHAN, QIU LINGYU, LIAO ZHANGPING, HUANG QIREN. DJ-1 upregulates anti-oxidant enzymes and attenuates hypoxia/re-oxygenation-induced oxidative stress by activation of the nuclear factor erythroid 2-like 2 signaling pathway. Mol Med Rep 2015; 12:4734-4742. [DOI: 10.3892/mmr.2015.3947] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2014] [Accepted: 05/15/2015] [Indexed: 11/06/2022] Open
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203
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Das J, Sarkar A, Sil PC. Hexavalent chromium induces apoptosis in human liver (HepG2) cells via redox imbalance. Toxicol Rep 2015; 2:600-608. [PMID: 28962395 PMCID: PMC5598256 DOI: 10.1016/j.toxrep.2015.03.013] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2015] [Revised: 03/30/2015] [Accepted: 03/30/2015] [Indexed: 12/14/2022] Open
Abstract
Hexavalent chromium, Cr(VI), is an environmental toxicant and is associated with hepatotoxicity. However, very little is known about the intracellular antioxidant defense mechanism against Cr(VI)-induced cytotoxicity in hepatocytes. In the present study, we cultured human liver (HepG2) cells in the absence or presence of Cr(VI) and determined its effect on cellular oxidative stress, mitochondrial damage, apoptosis and the expression of the transcription factor Nrf2 and the Nrf2-dependent antioxidant enzymes. Cr(VI) intoxication at a dose of 0, 3.125, 6.25, 12.5, 25, or 50 μM for 24 h exhibited a dose dependent cytotoxic effects in hepatocytes. Besides, Cr(VI) induced oxidative stress and subsequent mitochondrial damage. Cr(VI) also induced caspase 3-dependent apoptosis in HepG2 cells. In addition, Cr(VI) induced the translocation of Nrf2 into the nucleus and up-regulated the expression of Nrf2-dependent antioxidant enzymes, including SOD2, GCLC, and HO1. Our present experimental data support the notion that Cr(VI) caused mitochondrial damage, apoptosis, oxidative stress, and subsequently lead to a strong induction of HO1, GCLC and SOD2 via the Nrf-2 signaling pathway in hepatocytes.
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Affiliation(s)
| | | | - Parames C. Sil
- Division of Molecular Medicine, Bose Institute, P-1/12, CIT Scheme VII M, Kolkata 700054, India
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204
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Habib E, Linher-Melville K, Lin HX, Singh G. Expression of xCT and activity of system xc(-) are regulated by NRF2 in human breast cancer cells in response to oxidative stress. Redox Biol 2015; 5:33-42. [PMID: 25827424 PMCID: PMC4392061 DOI: 10.1016/j.redox.2015.03.003] [Citation(s) in RCA: 176] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2015] [Revised: 03/13/2015] [Accepted: 03/16/2015] [Indexed: 12/20/2022] Open
Abstract
Cancer cells adapt to high levels of oxidative stress in order to survive and proliferate by activating key transcription factors. One such master regulator, the redox sensitive transcription factor NF E2 Related Factor 2 (NRF2), controls the expression of cellular defense genes including those encoding intracellular redox-balancing proteins involved in glutathione (GSH) synthesis. Under basal conditions, Kelch-like ECH-associated protein 1 (KEAP1) targets NRF2 for ubiquitination. In response to oxidative stress, NRF2 dissociates from KEAP1, entering the nucleus and binding to the antioxidant response element (ARE) in the promoter of its target genes. Elevated reactive oxygen species (ROS) production may deplete GSH levels within cancer cells. System xc(-), an antiporter that exports glutamate while importing cystine to be converted into cysteine for GSH synthesis, is upregulated in cancer cells in response to oxidative stress. Here, we provided evidence that the expression of xCT, the light chain subunit of system xc(-), is regulated by NRF2 in representative human breast cancer cells. Hydrogen peroxide (H2O2) treatment increased nuclear translocation of NRF2, also increasing levels of xCT mRNA and protein and extracellular glutamate release. Overexpression of NRF2 up-regulated the activity of the xCT promoter, which contains a proximal ARE. In contrast, overexpression of KEAP1 repressed promoter activity and decreased xCT protein levels, while siRNA knockdown of KEAP1 up-regulated xCT protein levels and transporter activity. These results demonstrate the importance of the KEAP1/NRF2 pathway in balancing oxidative stress in breast cancer cells through system xc(-). We have previously shown that xCT is upregulated in various cancer cell lines under oxidative stress. In the current investigation, we focused on MCF-7 cells as a model for mechanistic studies.
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Affiliation(s)
- Eric Habib
- Department of Pathology and Molecular Medicine, McMaster University, Hamilton, Ontario, Canada L8S 4L8
| | - Katja Linher-Melville
- Department of Pathology and Molecular Medicine, McMaster University, Hamilton, Ontario, Canada L8S 4L8
| | - Han-Xin Lin
- Department of Pathology and Molecular Medicine, McMaster University, Hamilton, Ontario, Canada L8S 4L8
| | - Gurmit Singh
- Department of Pathology and Molecular Medicine, McMaster University, Hamilton, Ontario, Canada L8S 4L8.
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205
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Leinonen HM, Kansanen E, Pölönen P, Heinäniemi M, Levonen AL. Role of the Keap1-Nrf2 pathway in cancer. Adv Cancer Res 2015; 122:281-320. [PMID: 24974185 DOI: 10.1016/b978-0-12-420117-0.00008-6] [Citation(s) in RCA: 125] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The Kelch-like ECH-associated protein 1 (Keap1)-nuclear factor E2-related factor 2 (Nrf2) pathway is one of the major signaling cascades involved in cell defense and survival against endogenous and exogenous stress. While Nrf2 and its target genes provide protection against various age-related diseases including tumorigenesis, constitutively active Nrf2 in cancer cells increases the expression of cytoprotective genes and, consequently, enhances proliferation via metabolic reprogramming and inhibition of apoptosis. Herein, we review the current understanding of the regulation of Nrf2 in normal cells as well as its dual role in cancer. Furthermore, the mechanisms of Nrf2 dysregulation in cancer, consequences of unchecked Nrf2 activity, and therapies targeting the Keap1-Nrf2 system are discussed.
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Affiliation(s)
- Hanna M Leinonen
- Department of Biotechnology and Molecular Medicine, A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, P.O. Box 1627, Kuopio, Finland
| | - Emilia Kansanen
- Department of Biotechnology and Molecular Medicine, A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, P.O. Box 1627, Kuopio, Finland
| | - Petri Pölönen
- Department of Biotechnology and Molecular Medicine, A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, P.O. Box 1627, Kuopio, Finland; Institute of Biomedicine, School of Medicine, University of Eastern Finland, P.O. Box 1627, Kuopio, Finland
| | - Merja Heinäniemi
- Department of Biotechnology and Molecular Medicine, A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, P.O. Box 1627, Kuopio, Finland; Institute of Biomedicine, School of Medicine, University of Eastern Finland, P.O. Box 1627, Kuopio, Finland
| | - Anna-Liisa Levonen
- Department of Biotechnology and Molecular Medicine, A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, P.O. Box 1627, Kuopio, Finland.
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206
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Ai Q, Sun G, Luo Y, Dong X, Hu R, Meng X, Sun X. Ginsenoside Rb1 prevents hypoxia-reoxygenation-induced apoptosis in H9c2 cardiomyocytes via an estrogen receptor-dependent crosstalk among the Akt, JNK, and ERK 1/2 pathways using a label-free quantitative proteomics analysis. RSC Adv 2015. [DOI: 10.1039/c5ra02432c] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Rb1 prevents H/R-induced apoptosis of H9c2 cells via an estrogen receptor-dependent crosstalk among the Akt, JNK, and ERK 1/2 pathways.
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Affiliation(s)
- Qidi Ai
- Key Laboratory of Bioactive Substances and Resources Utilization of Chinese Herbal Medicine
- Ministry of Education
- Institute of Medicinal Plant Development
- Chinese Academy of Medical Sciences & Peking Union Medical College
- Beijing
| | - Guibo Sun
- Key Laboratory of Bioactive Substances and Resources Utilization of Chinese Herbal Medicine
- Ministry of Education
- Institute of Medicinal Plant Development
- Chinese Academy of Medical Sciences & Peking Union Medical College
- Beijing
| | - Yun Luo
- Key Laboratory of Bioactive Substances and Resources Utilization of Chinese Herbal Medicine
- Ministry of Education
- Institute of Medicinal Plant Development
- Chinese Academy of Medical Sciences & Peking Union Medical College
- Beijing
| | - Xi Dong
- Wenzhou Medical University
- Wenzhou
- P. R. China
| | - Ruifeng Hu
- Key Laboratory of Bioactive Substances and Resources Utilization of Chinese Herbal Medicine
- Ministry of Education
- Institute of Medicinal Plant Development
- Chinese Academy of Medical Sciences & Peking Union Medical College
- Beijing
| | - Xiangbao Meng
- Key Laboratory of Bioactive Substances and Resources Utilization of Chinese Herbal Medicine
- Ministry of Education
- Institute of Medicinal Plant Development
- Chinese Academy of Medical Sciences & Peking Union Medical College
- Beijing
| | - Xiaobo Sun
- Key Laboratory of Bioactive Substances and Resources Utilization of Chinese Herbal Medicine
- Ministry of Education
- Institute of Medicinal Plant Development
- Chinese Academy of Medical Sciences & Peking Union Medical College
- Beijing
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207
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Aripiprazole increases NAD(P)H–quinone oxidoreductase-1 and heme oxygenase-1 in PC12 cells. J Neural Transm (Vienna) 2014; 122:757-72. [DOI: 10.1007/s00702-014-1350-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2014] [Accepted: 12/04/2014] [Indexed: 12/30/2022]
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208
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Kaposi's sarcoma-associated herpesvirus induces Nrf2 activation in latently infected endothelial cells through SQSTM1 phosphorylation and interaction with polyubiquitinated Keap1. J Virol 2014; 89:2268-86. [PMID: 25505069 DOI: 10.1128/jvi.02742-14] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
UNLABELLED Nuclear factor erythroid 2-related factor 2 (Nrf2), the cellular master regulator of the antioxidant response, dissociates from its inhibitor Keap1 when activated by stress signals and participates in the pathogenesis of viral infections and tumorigenesis. Early during de novo infection of endothelial cells, KSHV induces Nrf2 through an intricate mechanism involving reactive oxygen species (ROS) and prostaglandin E2 (PGE2). When we investigated the Nrf2 activity during latent KSHV infection, we observed increased nuclear serine-40-phosphorylated Nrf2 in human KS lesions compared to that in healthy tissues. Using KSHV long-term-infected endothelial cells (LTC) as a cellular model for KS, we demonstrated that KSHV infection induces Nrf2 constitutively by extending its half-life, increasing its phosphorylation by protein kinase Cζ (PKCζ) via the infection-induced cyclooxygenase-2 (COX-2)/PGE2 axis and inducing its nuclear localization. Nrf2 knockdown in LTC decreased expression of antioxidant genes and genes involved in KS pathogenesis such as the NAD(P)H quinone oxidase 1 (NQO1), gamma glutamylcysteine synthase heavy unit (γGCSH), the cysteine transporter (xCT), interleukin 6 (IL-6), and vascular endothelial growth factor A (VEGF-A) genes. Nrf2 activation was independent of oxidative stress but dependent on the autophagic protein sequestosome-1 (SQSTM1; p62). SQSTM1 levels were elevated in LTC, a consequence of protein accumulation due to decreased autophagy and Nrf2-mediated transcriptional activation. SQSTM1 was phosphorylated on serine-351 and -403, while Keap1 was polyubiquitinated with lysine-63-ubiquitin chains, modifications known to increase their mutual affinity and interaction, leading to Keap1 degradation and Nrf2 activation. The latent KSHV protein Fas-associated death domain-like interleukin-1β-converting enzyme-inhibitory protein (vFLIP) increased SQSTM1 expression and activated Nrf2. Collectively, these results demonstrate that KSHV induces SQSTM1 to constitutively activate Nrf2, which is involved in the regulation of genes participating in KSHV oncogenesis. IMPORTANCE The transcription factor Nrf2 is activated by stress signals, including viral infection, and responds by activating the transcription of cytoprotective genes. Recently, Nrf2 has been implicated in oncogenesis and was shown to be activated during de novo KSHV infection of endothelial cells through ROS-dependent pathways. The present study was undertaken to determine the mechanism of Nrf2 activation during prolonged latent infection of endothelial cells, using an endothelial cell line latently infected with KSHV. We show that Nrf2 activation was elevated in KSHV latently infected endothelial cells independently of oxidative stress but dependent on the autophagic protein sequestosome-1 (SQSTM1), which was involved in the degradation of the Nrf2 inhibitor Keap1. Furthermore, our results indicated that the KSHV latent protein vFLIP participates in Nrf2 activation. This study suggests that KSHV hijacks the host's autophagic protein SQSTM1 to induce Nrf2 activation, thereby manipulating the infected host gene regulation to promote KS pathogenesis.
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209
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Greenwald MBY, Anzi S, Ben Sasson S, Bianco-Peled H, Kohen R. Can nitroxides evoke the Keap1-Nrf2-ARE pathway in skin? Free Radic Biol Med 2014; 77:258-69. [PMID: 25236737 DOI: 10.1016/j.freeradbiomed.2014.08.021] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/27/2014] [Revised: 07/29/2014] [Accepted: 08/20/2014] [Indexed: 01/14/2023]
Abstract
Nitroxides are stable cyclic radicals of diverse size, charge, and lipophilicity. They are cell-permeative, which effectively protects cells, tissues, isolated organs, and laboratory animals from radical-induced damage. The mechanisms of activity through which nitroxides operate are diverse, including superoxide dismutase-mimetic activity, oxidation of semiquinone radicals, oxidation of reduced metal ions, procatalase-mimetic activity, interruption of radical chain reactions, and indirect modulation of NO levels. Nitroxides possess both a nucleophilic (reducing properties) and an electrophilic (oxidizing properties) nature and, therefore, they may affect different cellular pathways. In the current study, a novel mechanism of action by which nitroxides provide skin protection based on their electrophilic nature is suggested. This study shows that nitroxides may act as electrophiles, directly or indirectly, capable of activating the Keap1-Nrf2-ARE pathway in human keratinocytes (HaCaT) and in human skin (human organ culture model). The high potency of oxoammonium cations versus hydroxylamines in activating the system is demonstrated. The mechanism of action by which nitroxides activate the Keap1-Nrf2-ARE pathway is discussed. Understanding the mechanism of activity may expand the usage of nitroxides as a skin protection strategy against oxidative stress-related conditions.
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Affiliation(s)
- Maya Ben Yehuda Greenwald
- The Institute for Drug Research, School of Pharmacy, The Hebrew University of Jerusalem, Jerusalem 91120, Israel; Department of Chemical Engineering and Technion-Israel Institute of Technology, Haifa 32000, Israel; The Russell Berrie Nanotechnology Institute, Technion-Israel Institute of Technology, Haifa 32000, Israel; Department of Developmental Biology and Cancer Research, The Hebrew University Medical School, Ein-Karem Campus, Jerusalem 91120, Israel
| | - Shira Anzi
- Department of Developmental Biology and Cancer Research, The Hebrew University Medical School, Ein-Karem Campus, Jerusalem 91120, Israel
| | - Shmuel Ben Sasson
- Department of Developmental Biology and Cancer Research, The Hebrew University Medical School, Ein-Karem Campus, Jerusalem 91120, Israel
| | - Havazelet Bianco-Peled
- Department of Chemical Engineering and Technion-Israel Institute of Technology, Haifa 32000, Israel; The Russell Berrie Nanotechnology Institute, Technion-Israel Institute of Technology, Haifa 32000, Israel
| | - Ron Kohen
- The Institute for Drug Research, School of Pharmacy, The Hebrew University of Jerusalem, Jerusalem 91120, Israel.
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210
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Nrf2, the master redox switch: The Achilles' heel of ovarian cancer? Biochim Biophys Acta Rev Cancer 2014; 1846:494-509. [DOI: 10.1016/j.bbcan.2014.09.004] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2014] [Revised: 09/13/2014] [Accepted: 09/17/2014] [Indexed: 12/21/2022]
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211
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Mine Y, Young D, Yang C. Antioxidative stress effect of phosphoserine dimers is mediated via activation of the Nrf2 signaling pathway. Mol Nutr Food Res 2014; 59:303-14. [DOI: 10.1002/mnfr.201400381] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2014] [Revised: 10/08/2014] [Accepted: 10/10/2014] [Indexed: 01/06/2023]
Affiliation(s)
- Yoshinori Mine
- Department of Food Science; University of Guelph; Guelph ON Canada
| | - Denise Young
- Department of Food Science; University of Guelph; Guelph ON Canada
| | - Chengbo Yang
- Department of Food Science; University of Guelph; Guelph ON Canada
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212
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Roy Chowdhury S, Sengupta S, Biswas S, Sinha TK, Sen R, Basak RK, Adhikari B, Bhattacharyya A. Bacterial fucose-rich polysaccharide stabilizes MAPK-mediated Nrf2/Keap1 signaling by directly scavenging reactive oxygen species during hydrogen peroxide-induced apoptosis of human lung fibroblast cells. Methods Enzymol 2014; 528:27-48. [PMID: 25412177 DOI: 10.1016/b978-0-12-405881-1.00002-1] [Citation(s) in RCA: 325] [Impact Index Per Article: 32.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Continuous free radical assault upsets cellular homeostasis and dysregulates associated signaling pathways to promote stress-induced cell death. In spite of the continuous development and implementation of effective therapeutic strategies, limitations in treatments for stress-induced toxicities remain. The purpose of the present study was to determine the potential therapeutic efficacy of bacterial fucose polysaccharides against hydrogen peroxide (H2O2)-induced stress in human lung fibroblast (WI38) cells and to understand the associated molecular mechanisms. In two different fermentation processes, Bacillus megaterium RB-05 biosynthesized two non-identical fucose polysaccharides; of these, the polysaccharide having a high-fucose content (∼ 42%) conferred the maximum free radical scavenging efficiency in vitro. Structural characterizations of the purified polysaccharides were performed using HPLC, GC-MS, and (1)H/(13)C/2D-COSY NMR. H2O2 (300 µM) insult to WI38 cells showed anti-proliferative effects by inducing intracellular reactive oxygen species (ROS) and by disrupting mitochondrial membrane permeability, followed by apoptosis. The polysaccharide (250 µg/mL) attenuated the cell death process by directly scavenging intracellular ROS rather than activating endogenous antioxidant enzymes. This process encompasses inhibition of caspase-9/3/7, a decrease in the ratio of Bax/Bcl2, relocalization of translocated Bax and cytochrome c, upregulation of anti-apoptotic members of the Bcl2 family and a decrease in the phosphorylation of MAPKs (mitogen activated protein kinases). Furthermore, cellular homeostasis was re-established via stabilization of MAPK-mediated Nrf2/Keap1 signaling and transcription of downstream cytoprotective genes. This molecular study uniquely introduces a fucose-rich bacterial polysaccharide as a potential inhibitor of H2O2-induced stress and toxicities.
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Affiliation(s)
- Sougata Roy Chowdhury
- Materials Science Centre, Indian Institute of Technology Kharagpur, West Bengal, India; Immunology lab, Department of Zoology, University of Calcutta, West Bengal, India
| | - Suman Sengupta
- Immunology lab, Department of Zoology, University of Calcutta, West Bengal, India
| | - Subir Biswas
- Immunology lab, Department of Zoology, University of Calcutta, West Bengal, India
| | - Tridib Kumar Sinha
- Materials Science Centre, Indian Institute of Technology Kharagpur, West Bengal, India
| | - Ramkrishna Sen
- Department of Biotechnology, Indian Institute of Technology Kharagpur, West Bengal, India
| | - Ratan Kumar Basak
- Materials Science Centre, Indian Institute of Technology Kharagpur, West Bengal, India
| | - Basudam Adhikari
- Materials Science Centre, Indian Institute of Technology Kharagpur, West Bengal, India
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213
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Venkatraman G, Benesch MGK, Tang X, Dewald J, McMullen TPW, Brindley DN. Lysophosphatidate signaling stabilizes Nrf2 and increases the expression of genes involved in drug resistance and oxidative stress responses: implications for cancer treatment. FASEB J 2014; 29:772-85. [PMID: 25398768 DOI: 10.1096/fj.14-262659] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The present work elucidates novel mechanisms for lysophosphatidate (LPA)-induced chemoresistance using human breast, lung, liver, and thyroid cancer cells. LPA (0.5-10 μM) increased Nrf2 transcription factor stability and nuclear localization by ≤5-fold. This involved lysophosphatidate type 1 (LPA1) receptors as identified with 1 μM wls-31 (LPA1/2 receptor agonist) and blocking this effect with 20 μM Ki16425 (LPA1-3 antagonist, Ki = 0.34 μM). Knockdown of LPA1 by 50% to 60% with siRNA decreased Nrf2 stability and expressing LPA1, but not LPA2/3, in human HepG2 cells increased Nrf2 stabilization. LPA-induced Nrf2 expression increased transcription of multidrug-resistant transporters and antioxidant genes by 2- to 4-fold through the antioxidant response element. This protected cells from doxorubicin-induced death. This pathway was verified in vivo by orthotopic injection of 20,000 mouse 4T1 breast cancer cells into syngeneic mice. Blocking LPA production with 10 mg/kg per d ONO-8430506 (competitive autotaxin inhibitor, IC90 = 100 nM) decreased expression of Nrf2, multidrug-resistant transporters, and antioxidant genes in breast tumors by ≤90%. Combining 4 mg/kg doxorubicin every third day with ONO-8430506 synergistically decreased tumor growth and metastasis to lungs and liver by >70%, whereas doxorubicin alone had no significant effect. This study provides the first evidence that LPA increases antioxidant gene and multidrug-resistant transporter expression. Blocking this aspect of LPA signaling provides a novel strategy for improving chemotherapy.
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Affiliation(s)
- Ganesh Venkatraman
- *Signal Transduction Research Group, Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada; and Department of Surgery, University of Alberta, WC Mackenzie Health Science Centre, Edmonton, Alberta, Canada
| | - Matthew G K Benesch
- *Signal Transduction Research Group, Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada; and Department of Surgery, University of Alberta, WC Mackenzie Health Science Centre, Edmonton, Alberta, Canada
| | - Xiaoyun Tang
- *Signal Transduction Research Group, Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada; and Department of Surgery, University of Alberta, WC Mackenzie Health Science Centre, Edmonton, Alberta, Canada
| | - Jay Dewald
- *Signal Transduction Research Group, Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada; and Department of Surgery, University of Alberta, WC Mackenzie Health Science Centre, Edmonton, Alberta, Canada
| | - Todd P W McMullen
- *Signal Transduction Research Group, Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada; and Department of Surgery, University of Alberta, WC Mackenzie Health Science Centre, Edmonton, Alberta, Canada
| | - David N Brindley
- *Signal Transduction Research Group, Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada; and Department of Surgery, University of Alberta, WC Mackenzie Health Science Centre, Edmonton, Alberta, Canada
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214
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Bhakkiyalakshmi E, Shalini D, Sekar TV, Rajaguru P, Paulmurugan R, Ramkumar KM. Therapeutic potential of pterostilbene against pancreatic beta-cell apoptosis mediated through Nrf2. Br J Pharmacol 2014; 171:1747-57. [PMID: 24417315 DOI: 10.1111/bph.12577] [Citation(s) in RCA: 87] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2013] [Revised: 12/02/2013] [Accepted: 12/23/2013] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND AND PURPOSE Nuclear factor erythroid 2-related factor 2 (Nrf2) is considered to be a 'master regulator' of the antioxidant response as it regulates the expression of several genes including phase II metabolic and antioxidant enzymes and thus plays an important role in preventing oxidative stress-mediated disorders, including diabetes. In this study, for the first time, we investigated the protective properties of a naturally available antioxidant, pterostilbene (PTS), against pancreatic beta-cell apoptosis and the involvement of Nrf2 in its mechanism of action. EXPERIMENTAL APPROACH Immunoblotting and quantitative reverse transcriptase (qRT)-PCR analysis were performed to identify PTS-mediated nuclear translocation of Nrf2 protein and the following activation of target gene expression, respectively, in INS-1E cells. In addition, an annexin-V binding assay was carried out to identify the apoptotic status of PTS-treated INS-1E cells, while confirming the anti-apoptotic potential of Nrf2 by qRT-PCR analysis of the expressions of both pro- and anti-apoptotic genes. KEY RESULTS PTS induced significant activation of Nrf2, in dose- and time-dependent manner, in streptozotocin-treated INS-1E rat pancreatic beta-cells. Furthermore, PTS increased the expression of target genes downstream of Nrf2, such as heme oxygenase 1 (HO1), superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx), that confer cellular protection. PTS also up-regulated the expression of anti-apoptotic gene, Bcl-2, with a concomitant reduction in pro-apoptotic Bax and caspase-3 expression. CONCLUSION AND IMPLICATIONS Collectively, our findings indicate the therapeutic potential of Nrf2 activation by PTS as a promising approach to safeguard pancreatic beta-cells against oxidative damage in diabetes.
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Affiliation(s)
- Elango Bhakkiyalakshmi
- Department of Biotechnology, School of Bioengineering, SRM University, Kattankulathur, Tamilnadu, India
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215
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Chowdhury SR, Sengupta S, Biswas S, Sen R, Sinha TK, Basak RK, Adhikari B, Bhattacharyya A. Low fucose containing bacterial polysaccharide facilitate mitochondria-dependent ROS-induced apoptosis of human lung epithelial carcinoma via controlled regulation of MAPKs-mediated Nrf2/Keap1 homeostasis signaling. Mol Carcinog 2014; 54:1636-55. [DOI: 10.1002/mc.22236] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2014] [Revised: 08/19/2014] [Accepted: 09/11/2014] [Indexed: 12/22/2022]
Affiliation(s)
- Sougata Roy Chowdhury
- Materials Science Centre; Indian Institute of Technology Kharagpur; Kharagpur WB India
- Department of Zoology; Immunology Lab; University of Calcutta; Kolkata WB India
| | - Suman Sengupta
- Department of Zoology; Immunology Lab; University of Calcutta; Kolkata WB India
| | - Subir Biswas
- Department of Zoology; Immunology Lab; University of Calcutta; Kolkata WB India
| | - Ramkrishna Sen
- Department of Biotechnology; Indian Institute of Technology Kharagpur; Kharagpur WB India
| | - Tridib Kumar Sinha
- Materials Science Centre; Indian Institute of Technology Kharagpur; Kharagpur WB India
| | - Ratan Kumar Basak
- Materials Science Centre; Indian Institute of Technology Kharagpur; Kharagpur WB India
| | - Basudam Adhikari
- Materials Science Centre; Indian Institute of Technology Kharagpur; Kharagpur WB India
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Bhakkiyalakshmi E, Sireesh D, Rajaguru P, Paulmurugan R, Ramkumar KM. The emerging role of redox-sensitive Nrf2-Keap1 pathway in diabetes. Pharmacol Res 2014; 91:104-14. [PMID: 25447793 DOI: 10.1016/j.phrs.2014.10.004] [Citation(s) in RCA: 103] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/11/2014] [Revised: 10/08/2014] [Accepted: 10/16/2014] [Indexed: 12/30/2022]
Abstract
The pathogenic processes involving in the development of diabetes range from autoimmune destruction of pancreatic β-cells with consequent insulin deficiency to abnormalities that result in resistance to insulin action. The major contributing factor for excessive β-cell death includes oxidative stress-mediated mitochondrial damage, which creates an imbalance in redox homeostasis. Yet, β-cells have evolved adaptive mechanisms to endure a wide range of stress conditions to safeguard its potential functions. These include 'Nrf2/Keap1' pathway, a key cellular defense mechanism, to combat oxidative stress by regulating phase II detoxifying and antioxidant genes. During diabetes, redox imbalance provokes defective Nrf2-dependent signaling and compromise antioxidant capacity of the pancreas which turnout β-cells to become highly vulnerable against various insults. Hence, identification of small molecule activators of Nrf2/Keap1 pathway remains significant to enhance cellular defense to overcome the burden of oxidative stress related disturbances. This review summarizes the molecular mechanism behind Nrf2 activation and the impact of Nrf2 activators in diabetes and its complications.
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Affiliation(s)
| | - Dornadula Sireesh
- SRM Research Institute, SRM University, Kattankulathur 603 203, Tamilnadu, India
| | - Palanisamy Rajaguru
- Department of Biotechnology, Anna University-BIT Campus, Tiruchirappalli 620 024, Tamilnadu, India
| | - Ramasamy Paulmurugan
- Department of Radiology, Stanford University School of Medicine, Palo Alto, CA 94304, USA
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217
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Rojo AI, McBean G, Cindric M, Egea J, López MG, Rada P, Zarkovic N, Cuadrado A. Redox control of microglial function: molecular mechanisms and functional significance. Antioxid Redox Signal 2014; 21:1766-801. [PMID: 24597893 PMCID: PMC4186766 DOI: 10.1089/ars.2013.5745] [Citation(s) in RCA: 232] [Impact Index Per Article: 23.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Neurodegenerative diseases are characterized by chronic microglial over-activation and oxidative stress. It is now beginning to be recognized that reactive oxygen species (ROS) produced by either microglia or the surrounding environment not only impact neurons but also modulate microglial activity. In this review, we first analyze the hallmarks of pro-inflammatory and anti-inflammatory phenotypes of microglia and their regulation by ROS. Then, we consider the production of reactive oxygen and nitrogen species by NADPH oxidases and nitric oxide synthases and the new findings that also indicate an essential role of glutathione (γ-glutamyl-l-cysteinylglycine) in redox homeostasis of microglia. The effect of oxidant modification of macromolecules on signaling is analyzed at the level of oxidized lipid by-products and sulfhydryl modification of microglial proteins. Redox signaling has a profound impact on two transcription factors that modulate microglial fate, nuclear factor kappa-light-chain-enhancer of activated B cells, and nuclear factor (erythroid-derived 2)-like 2, master regulators of the pro-inflammatory and antioxidant responses of microglia, respectively. The relevance of these proteins in the modulation of microglial activity and the interplay between them will be evaluated. Finally, the relevance of ROS in altering blood brain barrier permeability is discussed. Recent examples of the importance of these findings in the onset or progression of neurodegenerative diseases are also discussed. This review should provide a profound insight into the role of redox homeostasis in microglial activity and help in the identification of new promising targets to control neuroinflammation through redox control of the brain.
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Affiliation(s)
- Ana I Rojo
- 1 Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED) , Madrid, Spain
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Richter M, Winkel AF, Schummer D, Gerlitz M, de Hoop M, Brunner B, Glien M, Schmoll D. Pau d'arco activates Nrf2-dependent gene expression via the MEK/ERK-pathway. J Toxicol Sci 2014; 39:353-61. [PMID: 24646717 DOI: 10.2131/jts.39.353] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Pau d'arco is a plant-derived traditional medicine that acts by poorly understood molecular mechanisms. Here, we studied the effect of pau d'arco on the cytoprotective transcription factor Nrf2. An aqueous extract of pau d'arco stimulated Nrf2-dependent gene expression and led to nuclear localization of Nrf2 in vitro. Chromatographic separation and mass spectrometry of the extract identified benzene trioles or benzene tetraoles within the active fractions. The extract stimulated the mitogen-activated protein kinase/extracellular-signal-regulated kinase kinase (MEK)/extracellular-signal-regulated kinase (ERK1/2) pathway. The pharmacological inhibition of MEK, but not of p38 mitogen-activated protein kinase, glycogen synthase kinase-3 or phosphoinositide 3-kinase was required for the activation of Nrf2-dependent gene expression by pau d'arco, but not for the nuclear translocation of Nrf2. In vivo pau d'arco increased the expression of Nrf2-target genes in the intestine. The results suggest that the activation of Nrf2 could mediate beneficial effects of pau d'arco, in particular in the intestine.
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219
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Lee J, Kim S. Upregulation of heme oxygenase-1 expression by dehydrodiconiferyl alcohol (DHCA) through the AMPK-Nrf2 dependent pathway. Toxicol Appl Pharmacol 2014; 281:87-100. [PMID: 25261737 DOI: 10.1016/j.taap.2014.07.011] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2014] [Revised: 07/05/2014] [Accepted: 07/15/2014] [Indexed: 01/08/2023]
Abstract
Oxidative stress is induced by the accumulation of free radicals, resulting in an imbalanced cellular redox state, which has been implicated in a variety of human diseases. Dehydrodiconiferyl alcohol (DHCA), a lignan compound isolated from Cucurbita moschata, has previously been reported to contain anti-adipogenic and anti-lipogenic effects on 3T3-L1 cells and primary MEFs (Abraham and Kappas, 2008). In this study, it was tested whether DHCA could affect the expression of HO-1, using Raw264.7 mouse macrophage cell line. DHCA increased the protein and RNA levels of HO-1 and upregulated its promoter activity. Data from transient transfection assays indicated that ARE located in the E1 region of the HO-1 promoter are important in this DHCA-mediated induction of HO-1 expression. DHCA was also shown to enhance the nuclear translocation and binding of Nrf2 to the respective DNA sequences. The upregulation of HO-1 expression by DHCA was also observed in primary macrophages derived from wild type animals, but not in those from Nrf2 KO mice. Effects of DHCA on HO-1 and Nrf2 were reduced when cells were treated with an AMPK inhibitor, Compound C, but not by PI3K/Akt or MAPK inhibitors. Data from an experiment using a specific siRNA or chemical inhibitor for HO-1 suggested that the DHCA-mediated induction of the HO-1 protein could suppress the LPS-stimulated production of NO. Taken together, our data suggest that DHCA induces the expression of HO-1 by controlling its promoter activity through the AMPK-Nrf2 pathway, eventually leading to the reduction of NO production, and may thus have potential as an effective antioxidant.
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Affiliation(s)
- Junghun Lee
- Department of Biological Sciences, Seoul National University, Seoul 151-742, Korea
| | - Sunyoung Kim
- Department of Biological Sciences, Seoul National University, Seoul 151-742, Korea.
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220
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MDA-7/IL-24 inhibits Nrf2-mediated antioxidant response through activation of p38 pathway and inhibition of ERK pathway involved in cancer cell apoptosis. Cancer Gene Ther 2014; 21:416-26. [DOI: 10.1038/cgt.2014.45] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2014] [Revised: 07/24/2014] [Accepted: 07/25/2014] [Indexed: 11/08/2022]
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1,4-naphthoquinones: from oxidative damage to cellular and inter-cellular signaling. Molecules 2014; 19:14902-18. [PMID: 25232709 PMCID: PMC6270801 DOI: 10.3390/molecules190914902] [Citation(s) in RCA: 150] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2014] [Revised: 09/02/2014] [Accepted: 09/11/2014] [Indexed: 12/18/2022] Open
Abstract
Naphthoquinones may cause oxidative stress in exposed cells and, therefore, affect redox signaling. Here, contributions of redox cycling and alkylating properties of quinones (both natural and synthetic, such as plumbagin, juglone, lawsone, menadione, methoxy-naphthoquinones, and others) to cellular and inter-cellular signaling processes are discussed: (i) naphthoquinone-induced Nrf2-dependent modulation of gene expression and its potentially beneficial outcome; (ii) the modulation of receptor tyrosine kinases, such as the epidermal growth factor receptor by naphthoquinones, resulting in altered gap junctional intercellular communication. Generation of reactive oxygen species and modulation of redox signaling are properties of naphthoquinones that render them interesting leads for the development of novel compounds of potential use in various therapeutic settings.
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222
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Biswas C, Shah N, Muthu M, La P, Fernando AP, Sengupta S, Yang G, Dennery PA. Nuclear heme oxygenase-1 (HO-1) modulates subcellular distribution and activation of Nrf2, impacting metabolic and anti-oxidant defenses. J Biol Chem 2014; 289:26882-26894. [PMID: 25107906 DOI: 10.1074/jbc.m114.567685] [Citation(s) in RCA: 177] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
With oxidative injury as well as in some solid tumors and myeloid leukemia cells, heme oxygenase-1 (HO-1), the anti-oxidant, anti-inflammatory, and anti-apoptotic microsomal stress protein, migrates to the nucleus in a truncated and enzymatically inactive form. However, the function of HO-1 in the nucleus is not completely clear. Nuclear factor erythroid 2-related factor 2 (Nrf2), a transcription factor and master regulator of numerous antioxidants and anti-apoptotic proteins, including HO-1, also accumulates in the nucleus with oxidative injury and in various types of cancer. Here we demonstrate that in oxidative stress, nuclear HO-1 interacts with Nrf2 and stabilizes it from glycogen synthase kinase 3β (GSK3β)-mediated phosphorylation coupled with ubiquitin-proteasomal degradation, thereby prolonging its accumulation in the nucleus. This regulation of Nrf2 post-induction by nuclear HO-1 is important for the preferential transcription of phase II detoxification enzymes such as NQO1 as well as glucose-6-phosphate dehydrogenase (G6PDH), a regulator of the pentose phosphate pathway. Using Nrf2 knock-out cells, we further demonstrate that nuclear HO-1-associated cytoprotection against oxidative stress depends on an HO-1/Nrf2 interaction. Although it is well known that Nrf2 induces HO-1 leading to mitigation of oxidant stress, we propose a novel mechanism by which HO-1, by modulating the activation of Nrf2, sets an adaptive reprogramming that enhances antioxidant defenses.
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Affiliation(s)
- Chhanda Biswas
- Department of Pediatrics, University of Pennsylvania Philadelphia, Pennsylvania 19104 and; Division of Neonatology, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania 19104
| | - Nidhi Shah
- Division of Neonatology, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania 19104
| | - Manasa Muthu
- Division of Neonatology, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania 19104
| | - Ping La
- Division of Neonatology, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania 19104
| | - Amal P Fernando
- Division of Neonatology, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania 19104
| | - Shaon Sengupta
- Department of Pediatrics, University of Pennsylvania Philadelphia, Pennsylvania 19104 and; Division of Neonatology, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania 19104
| | - Guang Yang
- Division of Neonatology, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania 19104
| | - Phyllis A Dennery
- Department of Pediatrics, University of Pennsylvania Philadelphia, Pennsylvania 19104 and; Division of Neonatology, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania 19104.
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223
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Sid B, Glorieux C, Valenzuela M, Rommelaere G, Najimi M, Dejeans N, Renard P, Verrax J, Calderon PB. AICAR induces Nrf2 activation by an AMPK-independent mechanism in hepatocarcinoma cells. Biochem Pharmacol 2014; 91:168-80. [PMID: 25058527 DOI: 10.1016/j.bcp.2014.07.010] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2014] [Revised: 07/14/2014] [Accepted: 07/15/2014] [Indexed: 02/07/2023]
Abstract
Hepatocellular carcinoma is one of the most frequent tumor types worldwide and oxidative stress represents a major risk factor in pathogenesis of liver diseases leading to HCC. Nuclear factor erythroid 2-related factor (Nrf2) is a transcription factor activated by oxidative stress that governs the expression of many genes which constitute the antioxidant defenses of the cell. In addition, oxidative stress activates AMP-activated protein kinase (AMPK), which has emerged in recent years as a kinase that controls the redox-state of the cell. Since both AMPK and Nrf2 are involved in redox homeostasis, we investigated whether there was a crosstalk between the both signaling systems in hepatocarcinoma cells. Here, we demonstrated that AMPK activator AICAR, in contrary to the A769662 allosteric activator, induces Nrf2 activation and concomitantly modulates the basal redox state of the hepatocarcinoma cells. When the expression of Nrf2 is knocked down, AICAR failed to induce its effect on redox state. These data highlight a major role of Nrf2 signaling pathway in mediating the AICAR effect on basal oxidative state. Furthermore, we demonstrated that AICAR metabolization by the cell is required to induce Nrf2 activation while, the silencing of AMPK does not have any effect on Nrf2 activation. This suggests that AICAR-induced Nrf2 activation is independent of AMPK activity. In conclusion, we identified AICAR as a potent modulator of the redox state of human hepatocarcinoma cells, via the Nrf2 signaling pathway and in an AMPK-independent mechanism.
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Affiliation(s)
- Brice Sid
- Toxicology and Cancer Biology Research Group GTOX, Louvain Drug Research Institute, Université Catholique de Louvain, Brussels, Belgium
| | - Christophe Glorieux
- Toxicology and Cancer Biology Research Group GTOX, Louvain Drug Research Institute, Université Catholique de Louvain, Brussels, Belgium
| | - Manuel Valenzuela
- Toxicology and Cancer Biology Research Group GTOX, Louvain Drug Research Institute, Université Catholique de Louvain, Brussels, Belgium
| | - Guillaume Rommelaere
- Laboratory of Biochemistry and Cell Biology (URBC), NARILIS (NAmur Research Institute for Life Sciences), University of Namur (UNamur), Namur, Belgium
| | - Mustapha Najimi
- Laboratory of Pediatric Hepatology and Cell Therapy, Institut de Recherche Expérimentale et Clinique (IREC), Université Catholique de Louvain, Brussels, Belgium
| | - Nicolas Dejeans
- Toxicology and Cancer Biology Research Group GTOX, Louvain Drug Research Institute, Université Catholique de Louvain, Brussels, Belgium
| | - Patricia Renard
- Laboratory of Biochemistry and Cell Biology (URBC), NARILIS (NAmur Research Institute for Life Sciences), University of Namur (UNamur), Namur, Belgium
| | - Julien Verrax
- Toxicology and Cancer Biology Research Group GTOX, Louvain Drug Research Institute, Université Catholique de Louvain, Brussels, Belgium
| | - Pedro Buc Calderon
- Toxicology and Cancer Biology Research Group GTOX, Louvain Drug Research Institute, Université Catholique de Louvain, Brussels, Belgium; Facultad de Ciencias de la Salud, Universidad Arturo Prat, Iquique, Chile.
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224
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Hun Lee J, Shu L, Fuentes F, Su ZY, Tony Kong AN. Cancer chemoprevention by traditional chinese herbal medicine and dietary phytochemicals: targeting nrf2-mediated oxidative stress/anti-inflammatory responses, epigenetics, and cancer stem cells. J Tradit Complement Med 2014; 3:69-79. [PMID: 24716158 PMCID: PMC3924975 DOI: 10.4103/2225-4110.107700] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Excessive oxidative stress induced by reactive oxygen species (ROS), reactive nitrogen species (RNS), and reactive metabolites of carcinogens alters cellular homeostasis, leading to genetic/epigenetic changes, genomic instability, neoplastic transformation, and cancer initiation/progression. As a protective mechanism against oxidative stress, antioxidant/detoxifying enzymes reduce these reactive species and protect normal cells from endo-/exogenous oxidative damage. The transcription factor nuclear factor-erythroid 2 p45 (NF-E2)-related factor 2 (Nrf2), a master regulator of the antioxidative stress response, plays a critical role in the expression of many cytoprotective enzymes, including NAD(P)H:quinine oxidoreductase (NQO1), heme oxygenase-1 (HO-1), UDP-glucuronosyltransferase (UGT), and glutathione S-transferase (GST). Recent studies demonstrated that many dietary phytochemicals derived from various vegetables, fruits, spices, and herbal medicines induce Nrf2-mediated antioxidant/detoxifying enzymes, restore aberrant epigenetic alterations, and eliminate cancer stem cells (CSCs). The Nrf2-mediated antioxidant response prevents many age-related diseases, including cancer. Owing to their fundamental contribution to carcinogenesis, epigenetic modifications and CSCs are novel targets of dietary phytochemicals and traditional Chinese herbal medicine (TCHM). In this review, we summarize cancer chemoprevention by dietary phytochemicals, including TCHM, which have great potential as a safer and more effective strategy for preventing cancer.
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Affiliation(s)
- Jong Hun Lee
- Center for Cancer Prevention Research, Department of Pharmaceutics, Ernest Mario School of Pharmacy, Rutgers, the State University of New Jersey, 160 Frelinghuysen Road, Piscataway, NJ 08854, USA
| | - Limin Shu
- Center for Cancer Prevention Research, Department of Pharmaceutics, Ernest Mario School of Pharmacy, Rutgers, the State University of New Jersey, 160 Frelinghuysen Road, Piscataway, NJ 08854, USA
| | - Francisco Fuentes
- Center for Cancer Prevention Research, Department of Pharmaceutics, Ernest Mario School of Pharmacy, Rutgers, the State University of New Jersey, 160 Frelinghuysen Road, Piscataway, NJ 08854, USA ; Department of Desert Agriculture and Biotechnology, Arturo Prat University, PO box 121, Iquique, Chile
| | - Zheng-Yuan Su
- Center for Cancer Prevention Research, Department of Pharmaceutics, Ernest Mario School of Pharmacy, Rutgers, the State University of New Jersey, 160 Frelinghuysen Road, Piscataway, NJ 08854, USA
| | - Ah-Ng Tony Kong
- Center for Cancer Prevention Research, Department of Pharmaceutics, Ernest Mario School of Pharmacy, Rutgers, the State University of New Jersey, 160 Frelinghuysen Road, Piscataway, NJ 08854, USA
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225
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Patwardhan RS, Sharma D, Checker R, Sandur SK. Mitigation of radiation-induced hematopoietic injury via regulation of cellular MAPK/phosphatase levels and increasing hematopoietic stem cells. Free Radic Biol Med 2014; 68:52-64. [PMID: 24287141 DOI: 10.1016/j.freeradbiomed.2013.11.004] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/06/2013] [Revised: 10/31/2013] [Accepted: 11/05/2013] [Indexed: 11/22/2022]
Abstract
Here we describe a novel strategy for mitigation of ionizing radiation-induced hematopoietic syndrome by suppressing the activity of MKP3, resulting in ERK activation and enhanced abundance of hematopoietic stem cells, using the antioxidant flavonoid baicalein (5,6,7-trihydroxyflavone). It offered complete protection to mouse splenic lymphocytes against radiation-induced cell death. Inhibitors of ERK and Nrf-2 could significantly abrogate baicalein-mediated radioprotection in lymphocytes. Baicalein inhibited phosphatase MKP3 and thereby enhanced phosphorylation of ERK and its downstream proteins such as Elk and Nrf-2. It also increased the nuclear levels of Nrf-2 and the mRNA levels of its dependent genes. Importantly, baicalein administration to mice before radiation exposure led to significant recovery of loss of bone marrow cellularity and also inhibited cell death. Administration of baicalein increased the hematopoietic stem cell frequency as measured by side-population assay and also by antibody staining. Further, baicalein offered significant protection against whole-body irradiation (WBI; 7.5Gy)-induced mortality in mice. Interestingly, we found that baicalein works by activating the same target molecules ERK and Nrf-2 both in vitro and in vivo. Finally, administration of all-trans-retinoic acid (inhibitor of Nrf-2) significantly abrogated baicalein-mediated protection against WBI-induced mortality in mice. Thus, in contrast to the generalized conception of antioxidants acting as radioprotectors, we provide a rationale that antioxidants exhibit pleiotropic effects through the activation of multiple cellular signaling pathways.
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Affiliation(s)
- R S Patwardhan
- Radiation Biology and Health Sciences Division, Modular Laboratories, Bhabha Atomic Research Centre, Trombay, Mumbai 400085, India
| | - Deepak Sharma
- Radiation Biology and Health Sciences Division, Modular Laboratories, Bhabha Atomic Research Centre, Trombay, Mumbai 400085, India
| | - Rahul Checker
- Radiation Biology and Health Sciences Division, Modular Laboratories, Bhabha Atomic Research Centre, Trombay, Mumbai 400085, India
| | - Santosh K Sandur
- Radiation Biology and Health Sciences Division, Modular Laboratories, Bhabha Atomic Research Centre, Trombay, Mumbai 400085, India.
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226
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Gao B, Doan A, Hybertson BM. The clinical potential of influencing Nrf2 signaling in degenerative and immunological disorders. Clin Pharmacol 2014; 6:19-34. [PMID: 24520207 PMCID: PMC3917919 DOI: 10.2147/cpaa.s35078] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Nuclear factor (erythroid-derived 2)-like 2 (Nrf2; encoded in humans by the NFE2L2 gene) is a transcription factor that regulates the gene expression of a wide variety of cytoprotective phase II detoxification and antioxidant enzymes through a promoter sequence known as the antioxidant-responsive element (ARE). The ARE is a promoter element found in many cytoprotective genes; therefore, Nrf2 plays a pivotal role in the ARE-driven cellular defense system against environmental stresses. Agents that target the ARE/Nrf2 pathway have been tested in a wide variety of disorders, with at least one new Nrf2-activating drug now approved by the US Food and Drug Administration. Examination of in vitro and in vivo experimental results, and taking into account recent human clinical trial results, has led to an opinion that Nrf2-activating strategies – which can include drugs, foods, dietary supplements, and exercise – are likely best targeted at disease prevention, disease recurrence prevention, or slowing of disease progression in early stage illnesses; they may also be useful as an interventional strategy. However, this rubric may be viewed even more conservatively in the pathophysiology of cancer. The activation of the Nrf2 pathway has been widely accepted as offering chemoprevention benefit, but it may be unhelpful or even harmful in the setting of established cancers. For example, Nrf2 activation might interfere with chemotherapies or radiotherapies or otherwise give tumor cells additional growth and survival advantages, unless they already possess mutations that fully activate their Nrf2 pathway constitutively. With all this in mind, the ARE/Nrf2 pathway remains of great interest as a possible target for the pharmacological control of degenerative and immunological diseases, both by activation and by inhibition, and its regulation remains a promising biological target for the development of new therapies.
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Affiliation(s)
- Bifeng Gao
- Department of Medicine, Division of Pulmonary Sciences and Critical Care Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - An Doan
- Department of Medicine, Division of Pulmonary Sciences and Critical Care Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Brooks M Hybertson
- Department of Medicine, Division of Pulmonary Sciences and Critical Care Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
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Kim S, Lee HG, Park SA, Kundu JK, Keum YS, Cha YN, Na HK, Surh YJ. Keap1 cysteine 288 as a potential target for diallyl trisulfide-induced Nrf2 activation. PLoS One 2014; 9:e85984. [PMID: 24489685 PMCID: PMC3904845 DOI: 10.1371/journal.pone.0085984] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2013] [Accepted: 12/03/2013] [Indexed: 12/15/2022] Open
Abstract
Diallyl sulfide, diallyl disulfide, and daillyl trisulfide (DATS) are major volatile components of garlic oil. In this study, we assessed their relative potency in inducing antioxidant enzyme expression. Among the three organosulfur compounds, DATS was found to be most potent in inducing heme oxygenase-1 (HO-1) and NAD(P)H:quinone oxidoreductase-1 (NQO1) in human gastric epithelial (AGS) cells. Furthermore, DATS administration by gavage increased the expression of HO-1 and NQO1 in C57BL/6 mouse stomach. Treatment with DATS increased the accumulation of nuclear factor-erythroid-2-related factor-2 (Nrf2) in the nucleus of cultured AGS cells and in mouse stomach in vivo. The DATS-induced expression of HO-1 and NQO1 was abrogated in the cells transiently transfected with Nrf2-siRNA or in the embryonic fibroblasts from Nrf2-null mice, indicating that Nrf2 is a key mediator of the cytoprotective effects of DATS. Pretreatment of AGS cells with N-acetylcysteine or dithiothreitol attenuated DATS-induced nuclear localization of Nrf2 and the expression of HO-1 and NQO1. Cysteine-151, -273 and -288 of Kelch-like ECH-associated protein-1 (Keap1), a cytosolic repressor of Nrf2, have been considered to act as a redox sensor and play a role in Nrf2 activation. To determine whether DATS could inactivate Keap1 through thiol modification, we established cell lines constitutively expressing wild type-Keap1 or three different mutant constructs in which cysteine-151, -273, or -288 of Keap1 was replaced with serine by retroviral gene transfer. DATS failed to activate Nrf2, and to induce expression of HO-1 and NQO1 only in Keap1-C288S mutant cells. LC-ESI-MS/MS analysis of recombinant Keap1 treated with DATS revealed that the peptide fragment containing Cys288 gained a molecular mass of 72.1 Da equivalent to the molecular weight of mono-allyl mono-sulfide. Taken together, these findings suggest that DATS may directly interact with the Cys288 residue of Keap1, which partly accounts for its ability to induce Nrf2 activation and upregulate defensive gene expression.
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Affiliation(s)
- Sanghyun Kim
- Tumor Microenvironment Global Core Research Center, College of Pharmacy, Seoul National University, Seoul, South Korea
| | - Hee-Geum Lee
- Tumor Microenvironment Global Core Research Center, College of Pharmacy, Seoul National University, Seoul, South Korea
| | - Sin-Aye Park
- Tumor Microenvironment Global Core Research Center, College of Pharmacy, Seoul National University, Seoul, South Korea
| | | | - Young-Sam Keum
- College of Pharmacy, Dongguk University, Ilsan, South Korea
| | - Young-Nam Cha
- College of Medicine, Inha University, Incheon, South Korea
| | - Hye-Kyung Na
- Department of Food and Nutrition, Sungshin Women's University, Seoul, South Korea
| | - Young-Joon Surh
- Tumor Microenvironment Global Core Research Center, College of Pharmacy, Seoul National University, Seoul, South Korea
- Department of Molecular Medicine and Biopharmaceutical Sciences, Graduate School of Convergence Science and Technology, Seoul, South Korea
- Cancer Research Institute, Seoul National University, Seoul, South Korea
- * E-mail:
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Abstract
Continuous free radical assault upsets cellular homeostasis and dysregulates associated signaling pathways to promote stress-induced cell death. In spite of the continuous development and implementation of effective therapeutic strategies, limitations in treatments for stress-induced toxicities remain. The purpose of the present study was to determine the potential therapeutic efficacy of bacterial fucose polysaccharides against hydrogen peroxide (H2O2)-induced stress in human lung fibroblast (WI38) cells and to understand the associated molecular mechanisms. In two different fermentation processes, Bacillus megaterium RB-05 biosynthesized two non-identical fucose polysaccharides; of these, the polysaccharide having a high-fucose content (∼42%) conferred the maximum free radical scavenging efficiency in vitro. Structural characterizations of the purified polysaccharides were performed using HPLC, GC-MS, and 1H/13C/2D-COSY NMR. H2O2 (300 µM) insult to WI38 cells showed anti-proliferative effects by inducing intracellular reactive oxygen species (ROS) and by disrupting mitochondrial membrane permeability, followed by apoptosis. The polysaccharide (250 µg/mL) attenuated the cell death process by directly scavenging intracellular ROS rather than activating endogenous antioxidant enzymes. This process encompasses inhibition of caspase-9/3/7, a decrease in the ratio of Bax/Bcl2, relocalization of translocated Bax and cytochrome c, upregulation of anti-apoptotic members of the Bcl2 family and a decrease in the phosphorylation of MAPKs (mitogen activated protein kinases). Furthermore, cellular homeostasis was re-established via stabilization of MAPK-mediated Nrf2/Keap1 signaling and transcription of downstream cytoprotective genes. This molecular study uniquely introduces a fucose-rich bacterial polysaccharide as a potential inhibitor of H2O2-induced stress and toxicities.
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Astort F, Mercau M, Giordanino E, Degese MS, Caldareri L, Coso O, Cymeryng CB. Nitric oxide sets off an antioxidant response in adrenal cells: involvement of sGC and Nrf2 in HO-1 induction. Nitric Oxide 2013; 37:1-10. [PMID: 24361900 DOI: 10.1016/j.niox.2013.12.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2013] [Revised: 11/04/2013] [Accepted: 12/06/2013] [Indexed: 12/26/2022]
Abstract
Induction of microsomal heme oxygenase 1 (HO-1) activity is considered a cytoprotective mechanism in different cell types. In adrenal cells, HO-1 induction by ACTH exerts a modulatory effect on steroid production as well. As nitric oxide (NO) has been also regarded as an autocrine/paracrine modulator of adrenal steroidogenesis we sought to study the effects of NO on the induction of HO-1 and the mechanism involved. We hereby analyzed the time and dose-dependent effect of a NO-donor (DETA/NO) on HO-1 induction in a murine adrenocortical cell line. We showed that this effect is mainly exerted at a transcriptional level as it is inhibited by actinomycin D and HO-1 mRNA degradation rates were not affected by DETA/NO treatment. HO-1 induction by NO does not appear to involve the generation of oxidative stress as it was not affected by antioxidant treatment. We also demonstrated that NO-treatment results in the nuclear translocation of the nuclear factor-erythroid 2-related factor (Nrf2), an effect that is attenuated by transfecting the cells with a dominant negative isoform of Nrf2. We finally show that the effects of the NO-donor are reproduced by a permeable analog of cGMP and that a soluble guanylate cyclase specific inhibitor blocked both the induction of HO-1 by NO and the nuclear translocation of Nrf2.
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Affiliation(s)
- F Astort
- Departamento de Bioquímica Humana, Facultad de Medicina, Universidad de Buenos Aires, CEFYBO-CONICET, Argentina.
| | - M Mercau
- Departamento de Bioquímica Humana, Facultad de Medicina, Universidad de Buenos Aires, CEFYBO-CONICET, Argentina
| | - E Giordanino
- Departamento de Bioquímica Humana, Facultad de Medicina, Universidad de Buenos Aires, CEFYBO-CONICET, Argentina
| | - M S Degese
- LFBM-DFBMC, Departamento de Fisiología y Biología Molecular, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Argentina
| | - L Caldareri
- Departamento de Bioquímica Humana, Facultad de Medicina, Universidad de Buenos Aires, CEFYBO-CONICET, Argentina
| | - O Coso
- LFBM-DFBMC, Departamento de Fisiología y Biología Molecular, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Argentina
| | - C B Cymeryng
- Departamento de Bioquímica Humana, Facultad de Medicina, Universidad de Buenos Aires, CEFYBO-CONICET, Argentina
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230
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Kundu J, Kim DH, Kundu JK, Chun KS. Thymoquinone induces heme oxygenase-1 expression in HaCaT cells via Nrf2/ARE activation: Akt and AMPKα as upstream targets. Food Chem Toxicol 2013; 65:18-26. [PMID: 24355171 DOI: 10.1016/j.fct.2013.12.015] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2013] [Revised: 11/15/2013] [Accepted: 12/09/2013] [Indexed: 01/24/2023]
Abstract
Thymoquinone (TQ), an active constituent of Nigella sativa, possesses anti-inflammatory and anticancer properties. Multiple lines of evidence suggest that the induction of heme oxygenase-1 (HO-1) suppresses inflammation and carcinogenesis. In the present study, we examined the effect of TQ on HO-1 expression in human keratinocytes (HaCaT) and elucidated its underlying molecular mechanisms. TQ induced the expression of HO-1 in HaCaT cells in a concentration- and time-dependent manner. Treatment with TQ increased the localization of nuclear factor (NF)-erythroid2-(E2)-related factor-2 (Nrf2) in the nucleus and elevated the antioxidant response element (ARE)-reporter gene activity. Knockdown of Nrf2 abrogated TQ-induced HO-1 expression and the ARE luciferase activity. TQ induced the phosphorylation of extracellular signal-regulated kinase (ERK), Akt and cyclic AMP-activated protein kinase-α (AMPKα). Pharmacological inhibition of Akt or AMPKα, but not that of ERK, abrogated TQ-induced nuclear localization of Nrf2, the ARE-luciferase activity and the expression of HO-1. TQ also generated reactive oxygen species (ROS) and pretreatment with N-acetyl cysteine (NAC) abrogated TQ-induced ROS accumulation, Akt and AMPKα activation, Nrf2 nuclear localization, the ARE-luciferase activity, and HO-1 expression in HaCaT cells. Taken together, TQ induces HO-1 expression in HaCaT cells by activating Nrf2 through ROS-mediated phosphorylation of Akt and AMPKα.
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Affiliation(s)
- Juthika Kundu
- College of Pharmacy, Keimyung University, Daegu 704-701, South Korea
| | - Do-Hee Kim
- Tumor Microenvironment Global Core Research Center, College of Pharmacy, Seoul National University, Seoul 151-742, South Korea
| | | | - Kyung-Soo Chun
- College of Pharmacy, Keimyung University, Daegu 704-701, South Korea.
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231
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Eggler AL, Savinov SN. Chemical and biological mechanisms of phytochemical activation of Nrf2 and importance in disease prevention. RECENT ADVANCES IN PHYTOCHEMISTRY 2013; 43:121-155. [PMID: 26855455 DOI: 10.1007/978-3-319-00581-2_7] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Plants are an incredibly rich source of compounds that activate the Nrf2 transcription factor, leading to upregulation of a battery of cytoprotective genes. This perspective surveys established and proposed molecular mechanisms of Nrf2 activation by phytochemicals with a special emphasis on a common chemical property of Nrf2 activators: the ability as "soft" electrophiles to modify cellular thiols, either directly or as oxidized biotransformants. In addition, the role of reactive oxygen/nitrogen species as secondary messengers in Nrf2 activation is discussed. While the uniquely reactive C151 of Keap1, an Nrf2 repressor protein, is highlighted as a key target of cytoprotective phytochemicals, also reviewed are other stress-responsive proteins, including kinases, which play non-redundant roles in the activation of Nrf2 by plant-derived agents. Finally, the perspective presents two key factors accounting for the enhanced therapeutic windows of effective phytochemical activators of the Keap1-Nrf2 axis: enhanced selectivity toward sensor cysteines and reversibility of addition to thiolate molecules.
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Affiliation(s)
- Aimee L Eggler
- Department of Chemistry, Villanova University, 215a Mendel Science Hall, 800 Lancaster Avenue, Villanova, PA 19085
| | - Sergey N Savinov
- Purdue University Center for Cancer Research, West Lafayette, Indiana, 47907
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232
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Boilan E, Winant V, Dumortier E, Piret JP, Bonfitto F, Osiewacz HD, Debacq-Chainiaux F, Toussaint O. Role of p38MAPK and oxidative stress in copper-induced senescence. AGE (DORDRECHT, NETHERLANDS) 2013; 35:2255-2271. [PMID: 23576095 PMCID: PMC3824981 DOI: 10.1007/s11357-013-9521-3] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2012] [Accepted: 03/08/2013] [Indexed: 06/02/2023]
Abstract
In the present work, we indicate that copper is involved in the senescence of human diploid fibroblasts and we describe mechanisms to explain it. Using different techniques, we show for the first time an accumulation of copper in cells during replicative senescence. This accumulation seems to be co-localized with lipofuscin. Second, we observed that an incubation of cells with copper sulfate induced oxidative stress, antioxidant response and premature senescence. Antioxidant molecules reduced the appearance of premature senescence. Third, we found that Nrf2 transcription factor was activated and regulated the expression of genes involved in antioxidant response while p38(MAPK) regulated the appearance of premature senescence.
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Affiliation(s)
- Emmanuelle Boilan
- />NARILIS URBC, University of Namur (FUNDP), 61, rue de Bruxelles, 5000 Namur, Belgium
| | - Virginie Winant
- />NARILIS URBC, University of Namur (FUNDP), 61, rue de Bruxelles, 5000 Namur, Belgium
| | - Elise Dumortier
- />NARILIS URBC, University of Namur (FUNDP), 61, rue de Bruxelles, 5000 Namur, Belgium
| | - Jean-Pascal Piret
- />NARILIS URBC, University of Namur (FUNDP), 61, rue de Bruxelles, 5000 Namur, Belgium
| | - François Bonfitto
- />NARILIS URBC, University of Namur (FUNDP), 61, rue de Bruxelles, 5000 Namur, Belgium
| | - Heinz D. Osiewacz
- />Institute of Molecular Biosciences, Johann Wolfgang Goethe University, Frankfurt am Main, Germany
| | | | - Olivier Toussaint
- />NARILIS URBC, University of Namur (FUNDP), 61, rue de Bruxelles, 5000 Namur, Belgium
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233
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Sandberg M, Patil J, D'Angelo B, Weber SG, Mallard C. NRF2-regulation in brain health and disease: implication of cerebral inflammation. Neuropharmacology 2013; 79:298-306. [PMID: 24262633 DOI: 10.1016/j.neuropharm.2013.11.004] [Citation(s) in RCA: 281] [Impact Index Per Article: 25.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2013] [Revised: 10/17/2013] [Accepted: 11/08/2013] [Indexed: 12/13/2022]
Abstract
The nuclear factor erythroid 2 related factor 2 (NRF2) is a key regulator of endogenous inducible defense systems in the body. Under physiological conditions NRF2 is mainly located in the cytoplasm. However, in response to oxidative stress, NRF2 translocates to the nucleus and binds to specific DNA sites termed "anti-oxidant response elements" or "electrophile response elements" to initiate transcription of cytoprotective genes. Acute oxidative stress to the brain, such as stroke and traumatic brain injury is increased in animals that are deficient in NRF2. Insufficient NRF2 activation in humans has been linked to chronic diseases such as Parkinson's disease, Alzheimer's disease and amyotrophic lateral sclerosis. New findings have also linked activation of the NRF2 system to anti-inflammatory effects via interactions with NF-κB. Here we review literature on cellular mechanisms of NRF2 regulation, how to maintain and restore NRF2 function and the relationship between NRF2 regulation and brain damage. We bring forward the hypothesis that inflammation via prolonged activation of key kinases (p38 and GSK-3β) and activation of histone deacetylases gives rise to dysregulation of the NRF2 system in the brain, which contributes to oxidative stress and injury.
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Affiliation(s)
- Mats Sandberg
- Department of Medical Biochemistry and Cell Biology, Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, Sweden
| | - Jaspal Patil
- Department of Medical Biochemistry and Cell Biology, Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, Sweden
| | - Barbara D'Angelo
- Department of Physiology, Institute of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, Sweden
| | - Stephen G Weber
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA 15260, United States
| | - Carina Mallard
- Department of Physiology, Institute of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, Sweden.
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234
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Deng H. Multiple roles of Nrf2-Keap1 signaling: regulation of development and xenobiotic response using distinct mechanisms. Fly (Austin) 2013; 8:7-12. [PMID: 24406335 DOI: 10.4161/fly.27007] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Xenobiotic and oxidative responses protect cells from external and internal toxicities. Nrf2 and Keap1 are central factors that mediate these responses, and are closely related with many human diseases. In a recent study, we revealed novel developmental function and regulatory mechanism of Nrf2 and Keap1 by investigating their Drosophila homolog CncC and dKeap1. We found that CncC and dKeap1 control metamorphosis through regulations of ecdysone biosynthetic genes and ecdysone response genes in different tissues. CncC and dKeap1 cooperatively activate these developmental genes, in contrast to their conserved antagonizing effect to xenobiotic response transcription. In addition, interactions between CncC and Ras signaling in metamorphosis and in transcriptional regulation were established. Here I discuss the implications that place these classic xenobiotic response factors into a broader network that potentially control development and oncogenesis using mechanisms other than those mediating xenobiotic response.
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Affiliation(s)
- Huai Deng
- Department of Biological Chemistry; University of Michigan Medical School; Ann Arbor, MI USA
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235
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Turpaev KT. Keap1-Nrf2 signaling pathway: mechanisms of regulation and role in protection of cells against toxicity caused by xenobiotics and electrophiles. BIOCHEMISTRY (MOSCOW) 2013; 78:111-26. [PMID: 23581983 DOI: 10.1134/s0006297913020016] [Citation(s) in RCA: 82] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The transcription factor Nrf2 governs the expression of a considerable group of genes involved in cell protection against oxidants, electrophiles, and genotoxic compounds. The activity of Nrf2 is sensitive to xenobiotics and endogenous electrophiles. Nrf2 is negatively regulated by specific suppressor protein Keap1, which is also a receptor of electrophiles and adapter for Cul3 ubiquitin ligase. Electrophiles react with critical thiol groups of Keap1 leading to the loss of its ability to inhibit Nrf2. The Keap1-Nrf2 signaling pathway also down-regulates NF-κB transcriptional activity and attenuates cytokine-mediated induction of proinflammatory genes. Pharmacological activation of the Keap1-Nrf2 pathway can be used for treatment and prevention of many diseases. Widely known natural Keap1-Nrf2 activators include curcumin, quercetin, resveratrol, and sulforaphane. The most effective Keap1-Nrf2 activators are synthetic oleanane triterpenoids.
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Affiliation(s)
- K T Turpaev
- Center for Theoretical Problems of Physicochemical Pharmacology, Russian Academy of Sciences, 119991 Moscow, Russia.
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236
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Gum SI, Cho MK. Differential hepatic GSTA2 expression of arylalkyl isothiocyanates in vivo and in vitro: The molecular mechanism of gene induction by phenethyl isothiocyanate. Mol Nutr Food Res 2013; 57:2223-32. [DOI: 10.1002/mnfr.201300259] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2013] [Revised: 06/26/2013] [Accepted: 06/30/2013] [Indexed: 01/07/2023]
Affiliation(s)
- Sang Il Gum
- Department of Pharmacology; College of Oriental Medicine; Dongguk University; Kyungju Korea
| | - Min Kyung Cho
- Department of Pharmacology; College of Oriental Medicine; Dongguk University; Kyungju Korea
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237
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Redox activation of Nrf2 & NF-κB: a double end sword? Cell Signal 2013; 25:2548-57. [PMID: 23993959 DOI: 10.1016/j.cellsig.2013.08.007] [Citation(s) in RCA: 194] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2013] [Accepted: 08/23/2013] [Indexed: 12/20/2022]
Abstract
Moderate concentrations of reactive oxygen species (ROS) are produced by diverse sources under physiological conditions. At such low levels, these molecules may act as upstream mediators of relevant signaling pathways; however an increase in their concentration with respect to the antioxidant system activity, changes their redox signaling function into a deleterious role. Thus, cell health depends, at least in part, on redox balance. This review includes global aspects of oxygen chemistry, ROS generation, antioxidant system, and redox signaling. It is also focused on the description of two relevant redox-sensitive transcription factors: nuclear factor erythroid 2-related factor 2 (Nrf2), which may be a potential target to confer cell protection, and nuclear factor κB (NF-κB), which is involved in deleterious effects in the cell. Finally, recent findings on the interplay between both factors for the development of different pathologies are discussed.
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238
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Kim JH, Xu EY, Sacks DB, Lee J, Shu L, Xia B, Kong ANT. Identification and functional studies of a new Nrf2 partner IQGAP1: a critical role in the stability and transactivation of Nrf2. Antioxid Redox Signal 2013; 19:89-101. [PMID: 22793650 PMCID: PMC3689176 DOI: 10.1089/ars.2012.4586] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
AIMS Nuclear factor-erythroid-related factor 2 (Nrf2) is a critical transcriptional factor that is used in regulating cellular defense against oxidative stress. This study is aimed at investigating new interacting protein partners of Nrf2 using One-strep tag pull-down coupled with LTQ Orbitrap LC/MS/MS, and at examining the impact on Nr2 signaling by the newly identified IQ motif containing GTPase activating protein 1 (IQGAP1). RESULTS Using the One-strep tag pull-down and LTQ Orbitrap LC/MS/MS, we identified IQGAP1 as a new Nrf2 interacting partner. Direct interactions between IQGAP1 and Nrf2 proteins were verified using in vitro glutathione S-transferase (GST) pull-down, transcription/translation assays, and in vivo utilizing Nrf2 overexpressing cells. Coexpression of Dsredmono-IQGAP1 and eGFP-Nrf2 increased the stability of eGFP-Nrf2 and enhanced the expression of Nrf2-target gene heme oxygenase-1 (HO-1). To confirm the functional role of IQGAP1 on Nrf2, knock-downed IQGAP1 using siIQGAP1 attenuated the expression of endogenous Nrf2, HO-1 proteins, and Nrf2-target genes GSTpi, GCLC, and NAD(P)H quinone oxidoreductase 1 (NQO-1). Furthermore, the stability of Nrf2 was dramatically decreased in IQGAP1-deficient mouse embryonic fibroblast (MEF) cells. Since IQGAP1 signaling could be mediated by calcium, treating the cells with calcium showed the translocation of IQGAP1/Nrf2 complex into the nucleus, suggesting that IQGAP1 may play a critical role in Nrf2 stability. Interestingly, consistent with calcium signaling for IQGAP1, treating the cells with calcium functionally enhanced Nrf2-mediated antioxidant responsive element-transcription activity and enhanced the expression of the endogenous Nrf2-target gene HO-1. INNOVATION In the aggregate, our current study identifies and functionally characterizes a new Nrf2 partner protein IQGAP1, which may contribute to Nrf2's regulation of antioxidant enzymes such as HO-1. CONCLUSION IQGAP1 may play a critical role in the stability and transactivation of Nrf2.
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Affiliation(s)
- Jung-Hwan Kim
- Graduate Program in Pharmaceutical Science, Center for Cancer Prevention Research, Ernest-Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA
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239
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Patwardhan RS, Checker R, Sharma D, Sandur SK, Sainis KB. Involvement of ERK-Nrf-2 signaling in ionizing radiation induced cell death in normal and tumor cells. PLoS One 2013; 8:e65929. [PMID: 23776571 PMCID: PMC3679038 DOI: 10.1371/journal.pone.0065929] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2012] [Accepted: 05/01/2013] [Indexed: 12/30/2022] Open
Abstract
Prolonged oxidative stress favors tumorigenic environment and inflammation. Oxidative stress may trigger redox adaptation mechanism(s) in tumor cells but not normal cells. This may increase levels of intracellular antioxidants and establish a new redox homeostasis. Nrf-2, a master regulator of battery of antioxidant genes is constitutively activated in many tumor cells. Here we show that, murine T cell lymphoma EL-4 cells show constitutive and inducible radioresistance via activation of Nrf-2/ERK pathway. EL-4 cells contained lower levels of ROS than their normal counterpart murine splenic lymphocytes. In response to radiation, the thiol redox circuits, GSH and thioredoxin were modified in EL-4 cells. Pharmacological inhibitors of ERK and Nrf-2 significantly enhanced radiosensitivity and reduced clonogenic potential of EL-4 cells. Unirradiated lymphoma cells showed nuclear accumulation of Nrf-2, upregulation of its dependent genes and protein levels. Interestingly, MEK inhibitor abrogated its nuclear translocation suggesting role of ERK in basal and radiation induced Nrf-2 activation in tumor cells. Double knockdown of ERK and Nrf-2 resulted in higher sensitivity to radiation induced cell death as compared to individual knockdown cells. Importantly, NF-kB which is reported to be constitutively active in many tumors was not present at basal levels in EL-4 cells and its inhibition did not influence radiosensitivity of EL-4 cells. Thus our results reveal that, tumor cells which are subjected to heightened oxidative stress employ master regulator cellular redox homeostasis Nrf-2 for prevention of radiation induced cell death. Our study reveals the molecular basis of tumor radioresistance and highlights role of Nrf-2 and ERK.
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Affiliation(s)
- Raghavendra S. Patwardhan
- Radiation Biology & Health Sciences Division, Bio-Medical Group, Bhabha Atomic Research Centre, Trombay, Mumbai, India
| | - Rahul Checker
- Radiation Biology & Health Sciences Division, Bio-Medical Group, Bhabha Atomic Research Centre, Trombay, Mumbai, India
| | - Deepak Sharma
- Radiation Biology & Health Sciences Division, Bio-Medical Group, Bhabha Atomic Research Centre, Trombay, Mumbai, India
| | - Santosh K. Sandur
- Radiation Biology & Health Sciences Division, Bio-Medical Group, Bhabha Atomic Research Centre, Trombay, Mumbai, India
| | - Krishna B. Sainis
- Radiation Biology & Health Sciences Division, Bio-Medical Group, Bhabha Atomic Research Centre, Trombay, Mumbai, India
- * E-mail:
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240
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Castellano JM, Guinda A, Delgado T, Rada M, Cayuela JA. Biochemical basis of the antidiabetic activity of oleanolic acid and related pentacyclic triterpenes. Diabetes 2013; 62:1791-9. [PMID: 23704520 PMCID: PMC3661625 DOI: 10.2337/db12-1215] [Citation(s) in RCA: 157] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Oleanolic acid (OA), a natural component of many plant food and medicinal herbs, is endowed with a wide range of pharmacological properties whose therapeutic potential has only partly been exploited until now. Throughout complex and multifactorial mechanisms, OA exerts beneficial effects against diabetes and metabolic syndrome. It improves insulin response, preserves functionality and survival of β-cells, and protects against diabetes complications. OA may directly modulate enzymes connected to insulin biosynthesis, secretion, and signaling. However, its major contributions appear to be derived from the interaction with important transduction pathways, and many of its effects are consistently related to activation of the transcription factor Nrf2. Doing that, OA induces the expression of antioxidant enzymes and phase II response genes, blocks NF-κB, and represses the polyol pathway, AGEs production, and hyperlipidemia. The management of type 2 diabetes requires an integrated approach, which includes the early intervention to prevent or delay the disease progression, and the use of therapies to control glycemia and lipidemia in its late stages. In this sense, the use of functional foods or drugs containing OA is, undoubtedly, an interesting path.
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Affiliation(s)
- Jose M Castellano
- Instituto de la Grasa, Consejo Superior de Investigaciones Cientificas, Seville, Spain.
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241
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Mechanisms of Nrf2/Keap1-dependent phase II cytoprotective and detoxifying gene expression and potential cellular targets of chemopreventive isothiocyanates. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2013; 2013:839409. [PMID: 23781297 PMCID: PMC3679808 DOI: 10.1155/2013/839409] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/10/2013] [Accepted: 05/06/2013] [Indexed: 02/07/2023]
Abstract
Isothiocyanates (ITCs) are abundantly found in cruciferous vegetables. Epidemiological studies suggest that chronic consumption of cruciferous vegetables can lower the overall risk of cancer. Natural ITCs are key chemopreventive ingredients of cruciferous vegetables, and one of the prime chemopreventive mechanisms of natural isothiocyanates is the induction of Nrf2/ARE-dependent gene expression that plays a critical role in cellular defense against electrophiles and reactive oxygen species. In the present review, we first discuss the underlying mechanisms how natural ITCs affect the intracellular signaling kinase cascades to regulate the Keap1/Nrf2 activities, thereby inducing phase II cytoprotective and detoxifying enzymes. We also discuss the potential cellular protein targets to which natural ITCs are directly conjugated and how these events aid in the chemopreventive effects of natural ITCs. Finally, we discuss the posttranslational modifications of Keap1 and nucleocytoplasmic trafficking of Nrf2 in response to electrophiles and oxidants.
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242
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Srivastava S, Alfieri A, Siow RCM, Mann GE, Fraser PA. Temporal and spatial distribution of Nrf2 in rat brain following stroke: quantification of nuclear to cytoplasmic Nrf2 content using a novel immunohistochemical technique. J Physiol 2013; 591:3525-38. [PMID: 23690560 DOI: 10.1113/jphysiol.2013.257964] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Activation of the redox-sensitive transcription factor NF-E2 related factor 2 (Nrf2) affords protection against cerebral ischaemia-reperfusion injury via the upregulation of antioxidant defence genes. We have quantified for the first time Nrf2 content in brains from rats subjected to stroke and from cultured bEnd.3 brain endothelial cells using a novel immunohistochemical technique. Male Sprague-Dawley rats were subjected to middle cerebral artery occlusion for 70 min followed by reperfusion for 4, 24 or 72 h. Coronal brain sections were incubated with anti-Nrf2 primary and biotinylated-horseradish peroxidase-conjugated secondary antibody, after which sections were reacted with 3,3-diaminobenzidine (DAB) in the presence of hydrogen peroxide. The initial rates of DAB polymer formation were directly proportional to the Nrf2 protein concentration. Image processing was used to determine the temporal and spatial distribution of Nrf2 in nuclear and cytoplasmic compartments in stroke-affected and contralateral hemispheres. Nuclear to cytoplasmic Nrf2 ratios were increased in the stroke region after 24 h reperfusion and declined after 72 h reperfusion. Pretreatment with the Nrf2 inducer sulforaphane reduced total cellular Nrf2 levels in peri-infarct and core regions of the stroke hemisphere after 24 h reperfusion. Treatment of cultured murine brain endothelial cells with sulforaphane (2.5 μm) increased nuclear accumulation of Nrf2 over 1-4 h. We report the first quantitative measurements of spatial and temporal nuclear Nrf2 expression in rat brains following stroke, and show that sulforaphane pretreatment affects Nrf2 distribution in the brain of naïve rats and animals subjected to cerebral ischaemia. Our findings provide novel insights for targeting endogenous redox-sensitive antioxidant pathways to ameliorate the damaging consequences of stroke.
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Affiliation(s)
- Salil Srivastava
- Cardiovascular Division, BHF Centre of Research Excellence, School of Medicine, King's College London, Franklin-Wilkins Building, 150 Stamford Street, London SE1 9NH, UK
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243
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Liu R, Chen H, Bai H, Zhang W, Wang X, Qin X, Zhang X, Li W, Liang X, Hai C. Suppression of nuclear factor erythroid 2-related factor 2 via extracellular signal-regulated kinase contributes to bleomycin-induced oxidative stress and fibrogenesis. Toxicol Lett 2013; 220:15-25. [PMID: 23570914 DOI: 10.1016/j.toxlet.2013.03.034] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2013] [Revised: 03/29/2013] [Accepted: 03/30/2013] [Indexed: 01/07/2023]
Abstract
Pulmonary fibrosis is a serious and irreversible lung injury with obscure etiologic mechanisms and no effective treatment to date. This study explored a crucial link between oxidative stress and pulmonary fibrogenesis, focusing on nuclear factor erythroid 2-related factor 2 (Nrf2), a core transcription factor in antioxidative regulation systems. Treatment of C57 BL/6 mice with bleomycin increased fibroblast viability and collagen production and significantly downregulated Nrf2. In addition, prominent oxidative stress was indicated by changes in superoxide dismutase, catalase activity, and glutathione and thiobarbituric acid-reactive substance levels. In a cell-based model, bleomycin suppressed Nrf2 activation via extracellular signal-related kinase phosphorylation, enhancing intracellular reactive oxygen species in lung fibroblasts and stimulating abnormal cell proliferation and collagen secretion. To confirm this novel mechanism of bleomycin-induced fibrogenesis, we attempted to upregulate Nrf2 and related antioxidant proteins in bleomycin-treated fibroblasts using a putative Nrf2 activator, caffeic acid phenethyl ester, and the results showed that bleomycin-induced fibroblast proliferation and collagen content were attenuated through improved redox balance. Collectively, these results disclose a potential regulatory mechanism in pulmonary fibrosis that will aid the development of new therapies.
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Affiliation(s)
- Rui Liu
- Department of Toxicology, Shaanxi Key Lab of Free Radical Biology and Medicine, The Ministry of Education Key Lab of Hazard Assessment and Control in Special Operational Environment, School of Public Health, Fourth Military Medical University, Xi'an 710032, China
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244
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Nuclear factor-E2 (Nrf2) is regulated through the differential activation of ERK1/2 and PKC α/βII by Gymnasterkoreayne B. Cancer Lett 2013; 330:225-32. [DOI: 10.1016/j.canlet.2012.11.053] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2012] [Revised: 11/28/2012] [Accepted: 11/29/2012] [Indexed: 11/21/2022]
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245
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Malloy MT, McIntosh DJ, Walters TS, Flores A, Goodwin JS, Arinze IJ. Trafficking of the transcription factor Nrf2 to promyelocytic leukemia-nuclear bodies: implications for degradation of NRF2 in the nucleus. J Biol Chem 2013; 288:14569-14583. [PMID: 23543742 DOI: 10.1074/jbc.m112.437392] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Ubiquitylation of Nrf2 by the Keap1-Cullin3/RING box1 (Cul3-Rbx1) E3 ubiquitin ligase complex targets Nrf2 for proteasomal degradation in the cytoplasm and is an extensively studied mechanism for regulating the cellular level of Nrf2. Although mechanistic details are lacking, reports abound that Nrf2 can also be degraded in the nucleus. Here, we demonstrate that Nrf2 is a target for sumoylation by both SUMO-1 and SUMO-2. HepG2 cells treated with As2O3, which enhances attachment of SUMO-2/3 to target proteins, increased SUMO-2/3-modification (polysumoylation) of Nrf2. We show that Nrf2 traffics, in part, to promyelocytic leukemia-nuclear bodies (PML-NBs). Cell fractions harboring key components of PML-NBs did not contain biologically active Keap1 but contained modified Nrf2 as well as RING finger protein 4 (RNF4), a poly-SUMO-specific E3 ubiquitin ligase. Overexpression of wild-type RNF4, but not the catalytically inactive mutant, decreased the steady-state levels of Nrf2, measured in the PML-NB-enriched cell fraction. The proteasome inhibitor MG-132 interfered with this decrease, resulting in elevated levels of polysumoylated Nrf2 that was also ubiquitylated. Wild-type RNF4 accelerated the half-life (t½) of Nrf2, measured in PML-NB-enriched cell fractions. These results suggest that RNF4 mediates polyubiquitylation of polysumoylated Nrf2, leading to its subsequent degradation in PML-NBs. Overall, this work identifies Nrf2 as a target for sumoylation and provides a novel mechanism for its degradation in the nucleus, independent of Keap1.
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Affiliation(s)
- Melanie Theodore Malloy
- Department of Neuroscience and Pharmacology, School of Medicine, Meharry Medical College, Nashville, Tennessee 37208-3599
| | - Deneshia J McIntosh
- Department of Neuroscience and Pharmacology, School of Medicine, Meharry Medical College, Nashville, Tennessee 37208-3599
| | - Treniqka S Walters
- Department of Neuroscience and Pharmacology, School of Medicine, Meharry Medical College, Nashville, Tennessee 37208-3599
| | - Andrea Flores
- Department of Neuroscience and Pharmacology, School of Medicine, Meharry Medical College, Nashville, Tennessee 37208-3599
| | - J Shawn Goodwin
- Department of Biochemistry and Cancer Biology, School of Medicine, Meharry Medical College, Nashville, Tennessee 37208-3599
| | - Ifeanyi J Arinze
- Department of Physiology, School of Medicine, Meharry Medical College, Nashville, Tennessee 37208-3599.
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246
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Regulation of Drosophila metamorphosis by xenobiotic response regulators. PLoS Genet 2013; 9:e1003263. [PMID: 23408904 PMCID: PMC3567155 DOI: 10.1371/journal.pgen.1003263] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2012] [Accepted: 12/06/2012] [Indexed: 12/30/2022] Open
Abstract
Mammalian Nrf2-Keap1 and the homologous Drosophila CncC-dKeap1 protein complexes regulate both transcriptional responses to xenobiotic compounds as well as native cellular and developmental processes. The relationships between the functions of these proteins in xenobiotic responses and in development were unknown. We investigated the genes regulated by CncC and dKeap1 during development and the signal transduction pathways that modulate their functions. CncC and dKeap1 were enriched within the nuclei in many tissues, in contrast to the reported cytoplasmic localization of Keap1 and Nrf2 in cultured mammalian cells. CncC and dKeap1 occupied ecdysone-regulated early puffs on polytene chromosomes. Depletion of either CncC or dKeap1 in salivary glands selectively reduced early puff gene transcription. CncC and dKeap1 depletion in the prothoracic gland as well as cncCK6/K6 and dKeap1EY5/EY5 loss of function mutations in embryos reduced ecdysone-biosynthetic gene transcription. In contrast, dKeap1 depletion and the dKeap1EY5/EY5 loss of function mutation enhanced xenobiotic response gene transcription in larvae and embryos, respectively. Depletion of CncC or dKeap1 in the prothoracic gland delayed pupation by decreasing larval ecdysteroid levels. CncC depletion suppressed the premature pupation and developmental arrest caused by constitutive Ras signaling in the prothoracic gland; conversely, constitutive Ras signaling altered the loci occupied by CncC on polytene chromosomes and activated transcription of genes at these loci. The effects of CncC and dKeap1 on both ecdysone-biosynthetic and ecdysone-regulated gene transcription, and the roles of CncC in Ras signaling in the prothoracic gland, establish the functions of these proteins in the neuroendocrine axis that coordinates insect metamorphosis. Human Nrf2-Keap1 and the fruit fly CncC-dKeap1 protein complexes function both in response to foreign chemicals and in development. We found that CncC and dKeap1 control fruit fly development by regulating the production and actions of the principal hormone that controls the transformation of larvae into pupae. In hormone-responsive cells, CncC and dKeap1 bound to the genes that are activated by the hormone. When the amount of CncC or dKeap1 in these cells was reduced, the genes were not activated efficiently. When the amount of CncC or dKeap1 was reduced in the organ where the hormone is made, the genes whose products make the hormone were not activated efficiently. Because less hormone was made, it took longer for the larvae to turn into pupae, and the resulting pupae were bigger. Reduction of the amount of CncC intercepted previously identified signals for pupation. Nrf2 is required for the same signals to cause cancer in mice. The effects of CncC and dKeap1 both on genes that control hormone production and on genes that are switched on by the hormone in different organs indicate that they have multiple roles in the transformation of fruit fly larvae into pupae.
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247
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Zenkov NK, Menshchikova EB, Tkachev VO. Keap1/Nrf2/ARE redox-sensitive signaling system as a pharmacological target. BIOCHEMISTRY (MOSCOW) 2013; 78:19-36. [DOI: 10.1134/s0006297913010033] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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248
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Su ZY, Shu L, Khor TO, Lee JH, Fuentes F, Tony Kong AN. A perspective on dietary phytochemicals and cancer chemoprevention: oxidative stress, nrf2, and epigenomics. Top Curr Chem (Cham) 2013; 329:133-62. [PMID: 22836898 PMCID: PMC3924422 DOI: 10.1007/128_2012_340] [Citation(s) in RCA: 98] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Oxidative stress is caused by an imbalance of reactive oxygen species (ROS)/reactive nitrogen species (RNS) and the antioxidative stress defense systems in cells. ROS/RNS or carcinogen metabolites can attack intracellular proteins, lipids, and nucleic acids, which can result in genetic mutations, carcinogenesis, and other diseases. Nrf2 plays a critical role in the regulation of many antioxidative stress/antioxidant and detoxification enzyme genes, such as glutathione S-transferases (GSTs), NAD(P)H:quinone oxidoreductase 1 (NQO1), UDP-glucuronyl transferases (UGTs), and heme oxygenase-1 (HO-1), directly via the antioxidant response element (ARE). Recently, many studies have shown that dietary phytochemicals possess cancer chemopreventive potential through the induction of Nrf2-mediated antioxidant/detoxification enzymes and anti-inflammatory signaling pathways to protect organisms against cellular damage caused by oxidative stress. In addition, carcinogenesis can be caused by epigenetic alterations such as DNA methylation and histone modifications in tumor-suppressor genes and oncogenes. Interestingly, recent studies have shown that several naturally occurring dietary phytochemicals can epigenetically modify the chromatin, including reactivating Nrf2 via demethylation of CpG islands and the inhibition of histone deacetylases (HDACs) and/or histone acetyltransferases (HATs). The advancement and development of dietary phytochemicals in cancer chemoprevention research requires the integration of the known, and as-yet-unknown, compounds with the Nrf2-mediated antioxidant, detoxification, and anti-inflammatory systems and their in vitro and in vivo epigenetic mechanisms; human clinical efficacy studies must also be performed.
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Affiliation(s)
- Zheng-Yuan Su
- Department of Pharmaceutics, Center for Cancer Prevention Research, Ernest-Mario School of Pharmacy, Rutgers, the State University of New Jersey, 160 Frelinghuysen Road, Piscataway, NJ 08854, USA
| | - Limin Shu
- Department of Pharmaceutics, Center for Cancer Prevention Research, Ernest-Mario School of Pharmacy, Rutgers, the State University of New Jersey, 160 Frelinghuysen Road, Piscataway, NJ 08854, USA
| | - Tin Oo Khor
- Department of Pharmaceutics, Center for Cancer Prevention Research, Ernest-Mario School of Pharmacy, Rutgers, the State University of New Jersey, 160 Frelinghuysen Road, Piscataway, NJ 08854, USA
| | - Jong Hun Lee
- Department of Pharmaceutics, Center for Cancer Prevention Research, Ernest-Mario School of Pharmacy, Rutgers, the State University of New Jersey, 160 Frelinghuysen Road, Piscataway, NJ 08854, USA
| | - Francisco Fuentes
- Department of Pharmaceutics, Center for Cancer Prevention Research, Ernest-Mario School of Pharmacy, Rutgers, the State University of New Jersey, 160 Frelinghuysen Road, Piscataway, NJ 08854, USA, Departamento de Agricultura del Desierto y Biotecnología, Universidad Arturo Prat, Casilla 121, Iquique, Chile
| | - Ah-Ng Tony Kong
- Department of Pharmaceutics, Center for Cancer Prevention Research, Ernest-Mario School of Pharmacy, Rutgers, the State University of New Jersey, 160 Frelinghuysen Road, Piscataway, NJ 08854, USA
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NRF2 activation is involved in ozonated human serum upregulation of HO-1 in endothelial cells. Toxicol Appl Pharmacol 2012; 267:30-40. [PMID: 23253326 DOI: 10.1016/j.taap.2012.12.001] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2012] [Revised: 11/16/2012] [Accepted: 12/05/2012] [Indexed: 12/15/2022]
Abstract
During the last decade, it has been shown that the activation of NRF2 and the binding to electrophile-responsive element (EpREs), stimulates the expression of a great number of genes responsible for the synthesis of phase I and phase II proteins, including antioxidants enzymes and heme oxygenase-1 (HO-1). This critical cell response occurs in cardiovascular, degenerative and chronic infective diseases aggravated by a chronic oxidative stress. In our previous reports we have shown that ozonated plasma is able to up-regulate HO-1 expression in endothelial cells. In the present work we investigated a candidate mechanism involved in this process. After treatment with increasing doses of ozonated serum (20, 40 and 80 μg/mL O(3) per mL of serum), a clear dose dependent activation of NRF2 and the subsequent induction of HO-1 and NAD(P)H quinone oxidoreductase 1(NQO1) was observed. This effect was also present when cells were treated with serum and hydrogen peroxide (H(2)O(2)) or serum and 4-hydroxynonenal (4HNE). Moreover, the treatment with ozonated serum was associated with a dose-dependent activation of extracellular-signal-regulated kinases (ERK1/2) and p38 MAP kinases (p38), not directly involved in NRF2 activation. These data, provide a new insight on the mechanism responsible for the induction of HO-1 expression by ozonated serum in the endothelium, and have a practical importance as an expedient approach to the treatment of patients with both effective orthodox drugs and ozonated autohemotherapy, targeted to the restoration of redox homeostasis.
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250
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Kim M, Kim S, Lim JH, Lee C, Choi HC, Woo CH. Laminar flow activation of ERK5 protein in vascular endothelium leads to atheroprotective effect via NF-E2-related factor 2 (Nrf2) activation. J Biol Chem 2012; 287:40722-31. [PMID: 23043106 DOI: 10.1074/jbc.m112.381509] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
BACKGROUND Laminar flow protects from atherosclerosis in endothelium. RESULTS Laminar flow induces Nrf2 activation dependent on ERK5 activation, leading to up-regulation of downstream genes of Nrf2. CONCLUSION ERK5 requires Nrf2 activation to exert cytoprotective effect on HUVEC. ERK5 inhibitor BIX02189 regulates Nrf2 activation in vivo. SIGNIFICANCE Identifying ERK5 as a molecular target for regulating flow-mediating Nrf2-dependent gene expression may have significant therapeutic potential for treating atherosclerosis. Atherosclerosis is often observed in areas where disturbed flow is formed, whereas atheroprotective region is found in areas where steady laminar flow is developed. It has been reported that some genes activated by blood flow play important roles in vascular function and pathogenesis of atherosclerosis. Extracellular signal-regulated kinase 5 (ERK5) has been reported to regulate endothelial integrity and protect from vascular dysfunction and disease under laminar flow. Krüppel-like factor 2 (KLF2) and NF-E2-related factor 2 (Nrf2) are major transcriptional factors that contribute to anti-atherogenic responses under laminar flow. Implication of ERK5 in laminar flow-mediated regulation of KLF2-dependent gene has been established, whereas the role of ERK5 in laminar flow-mediated activation of Nrf2 pathway has not been addressed yet. In this study, we found that the blockage of ERK5 either by genetic depletion with siRNA or by biochemical inactivation with a specific chemical compound inhibited laminar flow-induced up-regulation of Nrf2-dependent gene expressions, whereas activation of ERK5 increased transcriptional activity and nuclear translocation of Nrf2, which suggests that ERK5 mediates laminar flow-induced up-regulation of Nrf2-dependent gene expression. Further functional studies showed that ERK5 provides protection against oxidative stress-induced cytotoxicity dependent on Nrf2. Molecular interaction between ERK5 and Nrf2 was further induced by laminar flow. Finally, flow-dependent nuclear localization of Nrf2 was inhibited by BIX02189, a specific inhibitor of MEK5, in aorta of mice in vivo. Collectively, these data demonstrate that laminar flow-induced activation of ERK5-Nrf2 signal pathway plays a critical role for anti-inflammatory and anti-apoptotic mechanism in endothelial cells.
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Affiliation(s)
- Miso Kim
- Department of Pharmacology, Yeungnam University College of Medicine, 317-1 Daemyung-dong, Daegu 705-717, Korea
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