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Onose Y, Ito Y, Kuwabara J, Kanbara T. Tracking side reactions of the inverse vulcanization process and developing monomer selection guidelines. Polym Chem 2022. [DOI: 10.1039/d2py00774f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Various olefin monomers were inverse-vulcanized. The structural analysis and evaluation of the thermal stability of the products revealed that aliphatic internal olefins are suitable monomers for suppressing side reactions.
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Affiliation(s)
- Yusuke Onose
- Tsukuba Research Center for Energy Materials Science (TREMS), Graduate School of Pure and Applied Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8573, Japan
| | - Yuri Ito
- Tsukuba Research Center for Energy Materials Science (TREMS), Graduate School of Pure and Applied Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8573, Japan
| | - Junpei Kuwabara
- Tsukuba Research Center for Energy Materials Science (TREMS), Graduate School of Pure and Applied Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8573, Japan
| | - Takaki Kanbara
- Tsukuba Research Center for Energy Materials Science (TREMS), Graduate School of Pure and Applied Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8573, Japan
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2
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Wati SM, Matsumaru D, Motohashi H. NRF2 pathway activation by KEAP1 inhibition attenuates the manifestation of aging phenotypes in salivary glands. Redox Biol 2020; 36:101603. [PMID: 32590331 PMCID: PMC7322188 DOI: 10.1016/j.redox.2020.101603] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Revised: 05/26/2020] [Accepted: 06/01/2020] [Indexed: 12/20/2022] Open
Abstract
Saliva plays an essential role in the maintenance of oral health. The oral cavity environment changes during aging mainly due to alterations in the secretion and composition of saliva. In particular, unstimulated basal salivary flow decreases with age. The functional decline of the salivary glands impairs chewing and swallowing abilities and often becomes one of the predispositions for aging-related disorders, including aspiration pneumonia. The KEAP1-NRF2 system plays a central role in the regulation of the oxidative stress response. NRF2 is a transcription factor that coordinately regulates cytoprotective genes, and KEAP1 is a negative regulator of NRF2. Although NRF2 activation has been suggested to be advantageous for the prevention of aging-related diseases, its role in the course of physiological aging is not well understood. To investigate the impact of NRF2 activation on salivary gland aging, we compared the submandibular glands of Keap1-knockdown (KD) (Keap1FA/FA) mice in which NRF2 is activated with those of wild-type mice. Young mice did not show any apparent differences between the two genotypes, whereas in old mice, clear differences were observed. Aged wild-type submandibular glands exhibited iron and collagen depositions, immune cell infiltration and increased DNA damage and apoptosis accompanied by elevated oxidative stress, which were all markedly attenuated in Keap1-KD mice, suggesting that NRF2 activation has antiaging effects on salivary glands. We propose that appropriate activation of NRF2 is effective for the maintenance of healthy salivary gland conditions and for the prevention of hyposalivation in the elderly. NRF2 pathway activities are similar in young and old submandibular glands. Keap1 knockdown increases NRF2 pathway activities in submandibular glands. NRF2 activation attenuates oxidative stress increase in old submandibular glands. NRF2 activation attenuates aging phenotypes in old submandibular glands.
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Affiliation(s)
- Sisca Meida Wati
- Department of Gene Expression Regulation, Institute of Development, Aging and Cancer, Tohoku University, Japan
| | - Daisuke Matsumaru
- Department of Gene Expression Regulation, Institute of Development, Aging and Cancer, Tohoku University, Japan
| | - Hozumi Motohashi
- Department of Gene Expression Regulation, Institute of Development, Aging and Cancer, Tohoku University, Japan.
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Potential Applications of NRF2 Modulators in Cancer Therapy. Antioxidants (Basel) 2020; 9:antiox9030193. [PMID: 32106613 PMCID: PMC7139512 DOI: 10.3390/antiox9030193] [Citation(s) in RCA: 88] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Revised: 02/21/2020] [Accepted: 02/21/2020] [Indexed: 01/17/2023] Open
Abstract
The nuclear factor erythroid 2-related factor 2 (NRF2)-Kelch-like ECH-associated protein 1 (KEAP1) regulatory pathway plays an essential role in protecting cells and tissues from oxidative, electrophilic, and xenobiotic stress. By controlling the transactivation of over 500 cytoprotective genes, the NRF2 transcription factor has been implicated in the physiopathology of several human diseases, including cancer. In this respect, accumulating evidence indicates that NRF2 can act as a double-edged sword, being able to mediate tumor suppressive or pro-oncogenic functions, depending on the specific biological context of its activation. Thus, a better understanding of the mechanisms that control NRF2 functions and the most appropriate context of its activation is a prerequisite for the development of effective therapeutic strategies based on NRF2 modulation. In line of principle, the controlled activation of NRF2 might reduce the risk of cancer initiation and development in normal cells by scavenging reactive-oxygen species (ROS) and by preventing genomic instability through decreased DNA damage. In contrast however, already transformed cells with constitutive or prolonged activation of NRF2 signaling might represent a major clinical hurdle and exhibit an aggressive phenotype characterized by therapy resistance and unfavorable prognosis, requiring the use of NRF2 inhibitors. In this review, we will focus on the dual roles of the NRF2-KEAP1 pathway in cancer promotion and inhibition, describing the mechanisms of its activation and potential therapeutic strategies based on the use of context-specific modulation of NRF2.
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Song ZL, Bai F, Zhang B, Fang J. Synthesis of Dithiolethiones and Identification of Potential Neuroprotective Agents via Activation of Nrf2-Driven Antioxidant Enzymes. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2020; 68:2214-2231. [PMID: 31986030 DOI: 10.1021/acs.jafc.9b06360] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Oxidative stress is implicated in the pathogenesis of a wide variety of neurodegenerative disorders, and accordingly, dietary supplement of exogenous antioxidants or/and upregulation of the endogenous antioxidant defense system are promising for therapeutic intervention or chemoprevention of neurodegenerative diseases. Nrf2, a master regulator of the cellular antioxidant machinery, cardinally participates in the transcription of cytoprotective genes against oxidative/electrophilic stresses. Herein, we report the synthesis of 59 structurally diverse dithiolethiones and evaluation of their neuroprotection against 6-hydroxydopamine- or H2O2-induced oxidative damages in PC12 cells, a neuron-like rat pheochromocytoma cell line. Initial screening identified compounds 10 and 11 having low cytotoxicity but conferring remarkable protection on PC12 cells from oxidative-mediated damages. Further studies demonstrated that both compounds upregulated a battery of antioxidant genes as well as corresponding genes' products. Significantly, silence of Nrf2 expression abolishes cytoprotection of 10 and 11, indicating targeting Nrf2 activation is pivotal for their cellular functions. Taken together, the two lead compounds discovered here with potent neuroprotective functions against oxidative stress via Nrf2 activation merit further development as therapeutic or chemopreventive candidates for neurodegenerative disorders.
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Affiliation(s)
- Zi-Long Song
- State Key Laboratory of Applied Organic Chemistry & College of Chemistry and Chemical Engineering , Lanzhou University , Lanzhou 730000 , China
| | - Feifei Bai
- State Key Laboratory of Applied Organic Chemistry & College of Chemistry and Chemical Engineering , Lanzhou University , Lanzhou 730000 , China
| | - Baoxin Zhang
- State Key Laboratory of Applied Organic Chemistry & College of Chemistry and Chemical Engineering , Lanzhou University , Lanzhou 730000 , China
| | - Jianguo Fang
- State Key Laboratory of Applied Organic Chemistry & College of Chemistry and Chemical Engineering , Lanzhou University , Lanzhou 730000 , China
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Emerging Screening Approaches in the Development of Nrf2-Keap1 Protein-Protein Interaction Inhibitors. Int J Mol Sci 2019; 20:ijms20184445. [PMID: 31509940 PMCID: PMC6770765 DOI: 10.3390/ijms20184445] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2019] [Revised: 09/04/2019] [Accepted: 09/04/2019] [Indexed: 12/11/2022] Open
Abstract
Due to role of the Keap1–Nrf2 protein–protein interaction (PPI) in protecting cells from oxidative stress, the development of small molecule inhibitors that inhibit this interaction has arisen as a viable approach to combat maladies caused by oxidative stress, such as cancers, neurodegenerative disease and diabetes. To obtain specific and genuine Keap1–Nrf2 inhibitors, many efforts have been made towards developing new screening approaches. However, there is no inhibitor for this target entering the clinic for the treatment of human diseases. New strategies to identify novel bioactive compounds from large molecular databases and accelerate the developmental process of the clinical application of Keap1–Nrf2 protein–protein interaction inhibitors are greatly needed. In this review, we have summarized virtual screening and other methods for discovering new lead compounds against the Keap1–Nrf2 protein–protein interaction. We also discuss the advantages and limitations of different strategies, and the potential of this PPI as a drug target in disease therapy.
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Disubstituted Dithiolethione ACDT Exerts Neuroprotective Effects Against 6-Hydroxydopamine-Induced Oxidative Stress in SH-SY5Y Cells. Neurochem Res 2019; 44:1878-1892. [DOI: 10.1007/s11064-019-02823-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2019] [Revised: 05/13/2019] [Accepted: 05/30/2019] [Indexed: 12/20/2022]
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7
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Dithiolethiones: a privileged pharmacophore for anticancer therapy and chemoprevention. Future Med Chem 2018; 10:1241-1260. [DOI: 10.4155/fmc-2017-0281] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Dithiolethiones are five-membered sulfur-containing cyclic scaffolds that exhibit antioxidative, anti-inflammatory, antithrombic and chemotherapeutic activities. Dithiolethiones display the chemopreventive and cytoprotective effects by activating the antioxidant response element and mounting the transcription of cytoprotective phase II enzymatic machinery. In addition, several classes of dithiolethiones efficiently modulate the activities of proteins that play crucial roles in normal and cancer cells, including glutathione S-transferase, cyclooxygenases and master regulator NF-κB. The present paper summarizes synthetic aspects, pharmacological potentials and biological attributes of dithiolethiones and its derivatives. Additionally, this review concludes with a discussion on how the current state-of-the-art technologies may help in defining a structure–activity relationship of dithiolethiones, thereby facilitating the design and synthesis of potent drug candidates.
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Wible RS, Tran QT, Fathima S, Sutter CH, Kensler TW, Sutter TR. Pharmacogenomics of Chemically Distinct Classes of Keap1-Nrf2 Activators Identify Common and Unique Gene, Protein, and Pathway Responses In Vivo. Mol Pharmacol 2018; 93:297-308. [PMID: 29367259 PMCID: PMC5832324 DOI: 10.1124/mol.117.110262] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2017] [Accepted: 01/19/2018] [Indexed: 12/11/2022] Open
Abstract
The Kelch-like erythroid-associated protein 1 (Keap1)-NF-E2-related factor 2 (Nrf2) signaling pathway is the subject of several clinical trials evaluating the effects of Nrf2 activation on the prevention of cancer and diabetes and the treatment of chronic kidney disease and multiple sclerosis. 3H-1,2-dithiole-3-thione (D3T) and 1-[2-cyano-3,12-dioxooleana-1,9(11)-dien-28-oyl]imidazole (CDDO-Im) are representative members of two distinct series of Nrf2 chemical activators. Previous reports have described activator-specific effects on Nrf2-dependent gene regulation and physiologic outcomes. Here we used a robust chemical genomics approach to characterize expression profiles between D3T and CDDO-Im in livers from wild-type and Nrf2-null mice. At equally efficacious doses in wild-type mice, 406 genes show common RNA responses to both treatments. These genes enriched the Nrf2-regulated pathways of antioxidant defense and xenobiotic metabolism. In addition, 197 and 745 genes were regulated uniquely in response to either D3T or CDDO-Im, respectively. Functional analysis of the D3T-regulated set showed a significant enrichment of Nrf2-regulated enzymes involved in cholesterol biosynthesis. This result was supported by Nrf2-dependent increases in lanosterol synthase and CYP51 protein expression. CDDO-Im had no effect on cholesterol biosynthesis regardless of the dose tested. However, unlike D3T, CDDO-Im resulted in Nrf2-dependent elevation of peroxisome proliferator α and Kruppel-like factor 13, as well as the coactivator peroxisome proliferator γ coactivator 1β, together indicating regulation of β-oxidation and lipid metabolic pathways. These findings provide novel insights into the pharmacodynamic action of these two activators of Keap1-Nrf2 signaling. Although both compounds modify Keap1 to affect canonical cytoprotective gene expression, additional unique sets of Nrf2-dependent genes were regulated by each agent with enrichment of selective metabolic pathways.
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Affiliation(s)
- Ryan S Wible
- Departments of Chemistry (R.S.W., T.R.S.) and Biological Sciences (C.H.S., T.R.S.,) and the W. Harry Feinstone Center for Genomic Research (R.S.W., S.F., T.R.S.), University of Memphis, Memphis, Tennessee; Department of Preventive Medicine, University of Tennessee Health Science Center, Memphis, Tennessee (Q.T.T.); Department of Environmental Health and Engineering, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland (T.W.K.); and Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, Pennsylvania (T.W.K.)
| | - Quynh T Tran
- Departments of Chemistry (R.S.W., T.R.S.) and Biological Sciences (C.H.S., T.R.S.,) and the W. Harry Feinstone Center for Genomic Research (R.S.W., S.F., T.R.S.), University of Memphis, Memphis, Tennessee; Department of Preventive Medicine, University of Tennessee Health Science Center, Memphis, Tennessee (Q.T.T.); Department of Environmental Health and Engineering, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland (T.W.K.); and Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, Pennsylvania (T.W.K.)
| | - Samreen Fathima
- Departments of Chemistry (R.S.W., T.R.S.) and Biological Sciences (C.H.S., T.R.S.,) and the W. Harry Feinstone Center for Genomic Research (R.S.W., S.F., T.R.S.), University of Memphis, Memphis, Tennessee; Department of Preventive Medicine, University of Tennessee Health Science Center, Memphis, Tennessee (Q.T.T.); Department of Environmental Health and Engineering, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland (T.W.K.); and Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, Pennsylvania (T.W.K.)
| | - Carrie H Sutter
- Departments of Chemistry (R.S.W., T.R.S.) and Biological Sciences (C.H.S., T.R.S.,) and the W. Harry Feinstone Center for Genomic Research (R.S.W., S.F., T.R.S.), University of Memphis, Memphis, Tennessee; Department of Preventive Medicine, University of Tennessee Health Science Center, Memphis, Tennessee (Q.T.T.); Department of Environmental Health and Engineering, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland (T.W.K.); and Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, Pennsylvania (T.W.K.)
| | - Thomas W Kensler
- Departments of Chemistry (R.S.W., T.R.S.) and Biological Sciences (C.H.S., T.R.S.,) and the W. Harry Feinstone Center for Genomic Research (R.S.W., S.F., T.R.S.), University of Memphis, Memphis, Tennessee; Department of Preventive Medicine, University of Tennessee Health Science Center, Memphis, Tennessee (Q.T.T.); Department of Environmental Health and Engineering, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland (T.W.K.); and Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, Pennsylvania (T.W.K.)
| | - Thomas R Sutter
- Departments of Chemistry (R.S.W., T.R.S.) and Biological Sciences (C.H.S., T.R.S.,) and the W. Harry Feinstone Center for Genomic Research (R.S.W., S.F., T.R.S.), University of Memphis, Memphis, Tennessee; Department of Preventive Medicine, University of Tennessee Health Science Center, Memphis, Tennessee (Q.T.T.); Department of Environmental Health and Engineering, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland (T.W.K.); and Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, Pennsylvania (T.W.K.)
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Metalloporphyrin-mediated aerobic oxidation of hydrocarbons in cumene: Co-substrate specificity and mechanistic consideration. MOLECULAR CATALYSIS 2017. [DOI: 10.1016/j.mcat.2017.07.007] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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10
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Gibault F, Bailly F, Corvaisier M, Coevoet M, Huet G, Melnyk P, Cotelle P. Molecular Features of the YAP Inhibitor Verteporfin: Synthesis of Hexasubstituted Dipyrrins as Potential Inhibitors of YAP/TAZ, the Downstream Effectors of the Hippo Pathway. ChemMedChem 2017; 12:954-961. [PMID: 28334506 DOI: 10.1002/cmdc.201700063] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Revised: 03/17/2017] [Indexed: 12/22/2022]
Abstract
Porphyrin derivatives, in particular verteporfin (VP), a photosensitizer initially designed for cancer therapy, have been identified as inhibitors of the YAP-TEAD interaction and transcriptional activity. Herein we report the efficient convergent synthesis of the dipyrrin half of protoporphyrin IX dimethyl ester (PPIX-DME), in which the sensitive vinyl group was created at the final stage by a dehydroiodination reaction. Two other dipyrrin derivatives were synthesized, including dipyrrin 19 [(Z)-2-((3,5-dimethyl-4-vinyl-2H-pyrrol-2-ylidene)methyl)-3,5-dimethyl-4-vinyl-1H-pyrrole], containing two vinyl groups. We found that VP and dipyrrin 19 showed significant inhibitory effects on TEAD transcriptional activity in MDA-MB-231 human breast cancer cells, whereas other compounds did not show significant changes. In addition, we observed a marked decrease in both YAP and TAZ levels following VP treatment, whereas dipyrrin 19 treatment primarily decreased the levels of YAP and receptor kinase AXL, a downstream target of YAP. Together, our data suggest that, due to their chemical structures, porphyrin- and dipyrrin-related derivatives can directly target YAP and/or TAZ proteins and inhibit TEAD transcriptional activity.
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Affiliation(s)
- Floriane Gibault
- Department of Onco and NeuroChemistry, University of Lille, INSERM UMR-S 1172, Jean-Pierre Aubert Research Center, 3, rue du professeur Laguesse, BP 83, 59006, Lille Cedex, France
| | - Fabrice Bailly
- Department of Onco and NeuroChemistry, University of Lille, INSERM UMR-S 1172, Jean-Pierre Aubert Research Center, 3, rue du professeur Laguesse, BP 83, 59006, Lille Cedex, France
| | - Matthieu Corvaisier
- Department of Mucins, Epithelial Differentiation and Carcinogenesis, University of Lille, INSERM UMR-S 1172, Jean-Pierre Aubert Research Center, Bâtiment Biserte, 1, place de Verdun, 59045, Lille Cedex, France
| | - Mathilde Coevoet
- Department of Onco and NeuroChemistry, University of Lille, INSERM UMR-S 1172, Jean-Pierre Aubert Research Center, 3, rue du professeur Laguesse, BP 83, 59006, Lille Cedex, France
| | - Guillemette Huet
- Department of Mucins, Epithelial Differentiation and Carcinogenesis, University of Lille, INSERM UMR-S 1172, Jean-Pierre Aubert Research Center, Bâtiment Biserte, 1, place de Verdun, 59045, Lille Cedex, France
| | - Patricia Melnyk
- Department of Onco and NeuroChemistry, University of Lille, INSERM UMR-S 1172, Jean-Pierre Aubert Research Center, 3, rue du professeur Laguesse, BP 83, 59006, Lille Cedex, France
| | - Philippe Cotelle
- Department of Onco and NeuroChemistry, University of Lille, INSERM UMR-S 1172, Jean-Pierre Aubert Research Center, 3, rue du professeur Laguesse, BP 83, 59006, Lille Cedex, France
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Mishra S, Katare DP. Synergistic Combination for Chemoprevention of Hepatocellular Carcinoma: An In Silico and In Vitro Approach. Basic Clin Pharmacol Toxicol 2016; 120:532-540. [PMID: 27987371 DOI: 10.1111/bcpt.12730] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Accepted: 11/29/2016] [Indexed: 01/11/2023]
Abstract
Combination therapy is one of the best methods to manage the fatality rate in hepatocellular carcinoma (HCC). This study aimed to formulate a synergistic combination of synthetic and herbal compounds for the treatment of HCC as well as to elucidate a possible signalling mechanism. MTT and enzymatic assay were performed to determine the synergistic effect of drug combination (sorafenib, vitamin K1 and trans-chalcone) on HepG2 cell lines after intoxication with H2 O2 . Protein-protein interaction and docking studies were performed using Pathwaylinker2.0 and Schrödinger's software application to find out the mechanism of action and major targets for drug combination. The overall in vitro result showed that combination of trans-chalcone, vitamin K1 and sorafenib (10, 5 and 5 μM concentration, respectively) enhanced the resistance against oxidative stress generated by H2 O2 . The interaction studies helped in identification of few targets for docking of ligands (trans-chalcone, vitamin K1 and sorafenib). The study reports the synergistic effects of the formulation that can protect the cells from oxidative stress and restore normal levels of cellular enzymes in HepG2 cell line. We were able to determine the mechanism of action of herbal and synthetic formulation through in silico studies. Finally, docking studies confirmed potential targets for inhibition of hepatocarcinogenesis.
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Affiliation(s)
- Savita Mishra
- Proteomics & Translational Research Lab, Centre for Medical Biotechnology, Institute of Biotechnology, Amity University Uttar Pradesh, Noida, India
| | - Deepshikha Pande Katare
- Proteomics & Translational Research Lab, Centre for Medical Biotechnology, Institute of Biotechnology, Amity University Uttar Pradesh, Noida, India
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Brown DA, Betharia S, Yen JH, Kuo PC, Mistry H. Further structure-activity relationships study of substituted dithiolethiones as glutathione-inducing neuroprotective agents. Chem Cent J 2016; 10:64. [PMID: 27812368 PMCID: PMC5070379 DOI: 10.1186/s13065-016-0210-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2016] [Accepted: 10/05/2016] [Indexed: 12/27/2022] Open
Abstract
Background Parkinson’s disease is a neurodegenerative disorder associated with oxidative stress and glutathione depletion. The induction of cellular glutathione levels by exogenous molecules is a promising neuroprotective approach to limit the oxidative damage that characterizes Parkinson’s disease pathophysiology. Dithiolethiones, a class of sulfur-containing heterocyclic molecules, are known to increase cellular levels of glutathione; however, limited information is available regarding the influence of dithiolethione structure on activity. Herein, we report the design, synthesis, and pharmacological evaluation of a further series of dithiolethiones in the SH-SY5Y neuroblastoma cell line. Results Our structure–activity relationships data show that dithiolethione electronic properties, given as Hammett σp constants, influence glutathione induction activity and compound toxicity. The most active glutathione inducer identified, 6a, dose-dependently protected cells from 6-hydroxydopamine toxicity. Furthermore, the protective effects of 6a were abrogated by the inhibitor of glutathione synthesis, buthionine sulfoximine, confirming the importance of glutathione in the protective activities of 6a. Conclusions The results of this study further delineate the relationship between dithiolethione chemical structure and glutathione induction. The neuroprotective properties of analog 6a suggest a role for dithiolethiones as potential antiparkinsonian agents.
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Affiliation(s)
- Dennis A Brown
- Department of Pharmaceutical Sciences, Manchester University College of Pharmacy, 10627 Diebold Rd, Fort Wayne, IN 46845 USA
| | - Swati Betharia
- Department of Pharmaceutical Sciences, Manchester University College of Pharmacy, 10627 Diebold Rd, Fort Wayne, IN 46845 USA
| | - Jui-Hung Yen
- Department of Microbiology and Immunology, Indiana University School of Medicine, 2101 E. Coliseum Blvd, Fort Wayne, IN 46805 USA
| | - Ping-Chang Kuo
- Department of Microbiology and Immunology, Indiana University School of Medicine, 2101 E. Coliseum Blvd, Fort Wayne, IN 46805 USA
| | - Hitesh Mistry
- Department of Pharmaceutical Sciences, Manchester University College of Pharmacy, 10627 Diebold Rd, Fort Wayne, IN 46845 USA
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Tanii H, Sugitani K, Saijoh K. Anti-Inflammatory and Antioxidant Effects of Repeated Exposure to Cruciferous Allyl Nitrile in Sensitizer-Induced Ear Edema in Mice. Med Sci Monit Basic Res 2016; 22:20-6. [PMID: 26932717 PMCID: PMC4807966 DOI: 10.12659/msmbr.897771] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Background Skin sensitizers induce allergic reactions through the induction of reactive oxygen species. Allyl nitrile from cruciferous vegetables has been reported to induce antioxidants and phase II detoxification enzymes in various tissues. We assessed the effects of repeated exposure to allyl nitrile on sensitizer-induced allergic reactions. Material/Methods Mice were dosed with allyl nitrile (0–200 μmol/kg), and then received a dermal application of 1 of 3 sensitizers on the left ear or 1 of 2 vehicles on the right ear. Quantitative assessment of edema was carried out by measuring the difference in weight between the portions taken from the right and left ears. We tested enzymes (superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), and thiobarbituric acid reactive substances (TBARS) in ears. Results Repeated exposure to allyl nitrile reduced edemas induced by glutaraldehyde and by 2, 4-dinitrochlorobenzene (DNCB), but not by formaldehyde. The repeated exposure decreased levels of TBARS, a marker of oxidative stress, induced by glutaraldehyde and by DNCB, but not by formaldehyde. Allyl nitrile elevated SOD levels for the 3 sensitizers, and CAT levels for formaldehyde and DNCB. Allyl nitrile also increased GPx levels for formaldehyde and DNCB, but not for glutaraldehyde. The reduced edemas were associated with changes in oxidative stress levels and antioxidant enzymes. Conclusions Repeated exposure to allyl nitrile reduced allergic reactions induced by glutaraldehyde and by DNCB, but not by formaldehyde. This reduction was associated with changes in ROS levels and antioxidant enzyme activities.
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Affiliation(s)
- Hideji Tanii
- Department of Hygiene, Graduate School of Medical Science, Kanazawa University, Kanazawa, Japan
| | - Kayo Sugitani
- Division of Health Sciences, Graduate School of Medicine, Kanazawa University, Kanazawa, Japan
| | - Kiyofumi Saijoh
- Department of Hygiene, Graduate School of Medical Science, Kanazawa University, Kanazawa, Japan
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14
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Huang Y, Li W, Su ZY, Kong ANT. The complexity of the Nrf2 pathway: beyond the antioxidant response. J Nutr Biochem 2015; 26:1401-13. [PMID: 26419687 DOI: 10.1016/j.jnutbio.2015.08.001] [Citation(s) in RCA: 299] [Impact Index Per Article: 33.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2015] [Accepted: 08/03/2015] [Indexed: 12/11/2022]
Abstract
The NF-E2-related factor 2 (Nrf2)-mediated signalling pathway provides living organisms an efficient and pivotal line of defensive to counteract environmental insults and endogenous stressors. Nrf2 coordinates the basal and inducible expression of antioxidant and Phase II detoxification enzymes to adapt to different stress conditions. The stability and cellular distribution of Nrf2 is tightly controlled by its inhibitory binding protein Kelch-like ECH-associated protein 1. Nrf2 signalling is also regulated by posttranslational, transcriptional, translational and epigenetic mechanisms, as well as by other protein partners, including p62, p21 and IQ motif-containing GTPase activating protein 1. Many studies have demonstrated that Nrf2 is a promising target for preventing carcinogenesis and other chronic diseases, including cardiovascular diseases, neurodegenerative diseases and pulmonary injury. However, constitutive activation of Nrf2 in advanced cancer cells may confer drug resistance. Here, we review the molecular mechanisms of Nrf2 signalling, the diverse classes of Nrf2 activators, including bioactive nutrients and other chemicals, and the cellular functions and disease relevance of Nrf2 and discuss the dual role of Nrf2 in different contexts.
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Affiliation(s)
- Ying Huang
- Department of Pharmaceutics, Earnest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA
| | - Wenji Li
- Department of Pharmaceutics, Earnest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA
| | - Zheng-yuan Su
- Department of Pharmaceutics, Earnest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA
| | - Ah-Ng Tony Kong
- Department of Pharmaceutics, Earnest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA.
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15
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Searching phase II enzymes inducers, from Michael acceptor-[1,2]dithiolethione hybrids, as cancer chemopreventive agents. Future Med Chem 2015; 7:857-71. [DOI: 10.4155/fmc.15.32] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Background: Cancer chemoprevention involves the carcinogenic process prevention, delay or reverse by the administration of chemopreventive agents, which are able to suppress or block the carcinogen metabolic activation/formation. The increased activity of phase II detoxification enzymes such as quinone-reductase (QR) and glutation-S-transferase (GST) correlates with the protection against chemically-induced carcinogenesis. It has been shown that synthetic chalcones and 3H-[1,2]-dithiole-3-thiones promote expression of genes involved in chemoprevention. Materials & Methods: Herein, the induction of phase II enzymes by designed Michael acceptor-dithiolethione hybrids was studied. Results & Discussion: Hybrids 5 and 7 displayed the induction of quinone-reductase and glutation-S-transferase in vitro in the same order on the wild-type mouse-hepatoma Hepa 1c1c7 and on the aryl-hydrocarbon-nuclear-translocator (Arnt)-defective mutant BPrc1 cells indicating that 7 displays the best chemopreventive potential.
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16
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Synthesis and structure-activity relationships study of dithiolethiones as inducers of glutathione in the SH-SY5Y neuroblastoma cell line. Bioorg Med Chem Lett 2014; 24:5829-5831. [PMID: 25455499 DOI: 10.1016/j.bmcl.2014.10.005] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2014] [Revised: 09/26/2014] [Accepted: 10/01/2014] [Indexed: 11/24/2022]
Abstract
Parkinson's disease is a neurodegenerative disorder that involves the degeneration of nigrostriatal dopaminergic neurons. Elevated levels of reactive oxygen species have been shown to deplete cellular levels of the ubiquitous antioxidant glutathione, leading to oxidative stress and eventual neuronal cell death. Dithiolethiones, a class of sulfur-containing heterocyclic molecules, have been shown to induce cellular production of glutathione in a variety of tissues, but have not been extensively evaluated in neurons. Herein, we report the synthesis and preliminary structure-activity relationships study of several substituted dithiolethiones. Three molecules were identified (D3T, CPDT, and 2d) that potently induced cellular glutathione in the SH-SY5Y neuroblastoma cell line. Furthermore, these compounds were found to provide neuroprotection in the 6-hydroxydopamine model of neurotoxicity. This study suggests that dithiolethione-mediated neuroprotection may have potential as a disease-modifying antiparkinsonian therapy.
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17
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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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18
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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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19
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Recent Progress in 1,2-Dithiole-3-thione Chemistry. ADVANCES IN HETEROCYCLIC CHEMISTRY 2013. [DOI: 10.1016/b978-0-12-407777-5.00001-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/04/2023]
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20
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Müller T, Hengstermann A. Nrf2: friend and foe in preventing cigarette smoking-dependent lung disease. Chem Res Toxicol 2012; 25:1805-24. [PMID: 22686525 DOI: 10.1021/tx300145n] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Chronic exposure to cigarette smoke (CS) generally confronts cellular defense systems with one of the strongest known environmental challenges. In particular, the continuous exposure of tissues of the respiratory tract to abundant concentrations of radicals; volatile compounds of the gas phase, mainly reactive oxygen and nitrogen species; and CS condensate deposits trigger a pleiotropic adaptive response, generally aimed at restoring tissue homeostasis. As documented by numerous studies published over the past decade, a hallmark of this defense system is the activation of the transcription factor NF-E2-related factor 2 (Nrf2), which, consequent to its established role as master regulator of the cellular antioxidant response, has been shown to orchestrate the first line of defense against cell- and tissue-damaging components present in CS. The key to CS-dependent Nrf2 activation is assumed to be based on the long-known phenomenon of a general strong sulfhydryl (-SH) reactivity inherent to CS. This chemical trait is virtually predestined to be sensitized by the major route leading to Nrf2 activation, characterized by its dependence on the interaction of electrophiles with specific cysteine residues inherited by Nrf2's negative cytosolic regulator Keap1 (Kelch-like ECH-associated protein 1). In addition, other pathways involving CS-activated protein kinases implicated in the upstream regulation of Nrf2, such as protein kinase C, represent an alternative/complementary mechanism of CS-induced Nrf2 activation. Because of the outstanding function of the Nrf2-Keap1 axis in defending cells and tissues against oxidant and chemical stress, either directly or indirectly via cross-talking with other defense pathways, changes in the Nrf2 or Keap1 genotype have long been associated with disease development. In terms of the two major smoking-related diseases of the lung, that is, emphysema and lung cancer, a fully functional Nrf2 genotype seems to be necessary, although not sufficient by itself, to protect the smoker from acquiring emphysema. Contrasting with this protective role, however, Nrf2 function may be potentially fatal in smoking-related lung tumorigenesis: as concluded from recent clinical investigations, lung tumor tissues harbor increased mutation or, alternatively, aberrant expression rates in either the KEAP1 or the NRF2 gene, generally resulting in constitutive Nrf2 activation, suggesting that "abuse" of Nrf2 function is an advantageous strategy of the (developing) tumor to protect itself against oxidative stress in general. On the basis of the fundamental significance of the Nrf2 pathway in smoking-dependent disease development, several attempts have been described for dietary and pharmacological intervention, the majority of which are intended to activate Nrf2 aiming at emphysema prevention. The intention of this review is to compile and discuss the various aspects of CS-Nrf2/Keap1 interaction in terms of mechanism, disease development, and chemoprevention.
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Affiliation(s)
- Thomas Müller
- Molecular Toxicology Consultant, Stockbergergasse 15, 51515 Kürten, Germany.
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21
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Hoffman M, Rajapakse A, Shen X, Gates KS. Generation of DNA-damaging reactive oxygen species via the autoxidation of hydrogen sulfide under physiologically relevant conditions: chemistry relevant to both the genotoxic and cell signaling properties of H(2)S. Chem Res Toxicol 2012; 25:1609-15. [PMID: 22621314 DOI: 10.1021/tx300066z] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Hydrogen sulfide (H(2)S) has long been known for its toxic properties; however, in recent years, evidence has emerged that this small, gaseous molecule may serve as an endogenous cell-signaling agent. Though perhaps surprising in light of its potential role as an endogenous signaling agent, a number of studies have provided evidence that H(2)S is a DNA-damaging mutagen. In the work reported here, the chemical mechanisms of DNA damage by H(2)S were examined. Using a plasmid-based DNA strand cleavage assay, we found that micromolar concentrations of H(2)S generated single-strand DNA cleavage. Mechanistic studies indicate that this process involved autoxidation of H(2)S to generate superoxide, hydrogen peroxide, and, ultimately, the well-known DNA-damaging agent hydroxyl radical via a trace metal-mediated Fenton-type reaction. Strand cleavage by H(2)S proceeded in the presence of physiological thiol concentrations, and the known byproducts of H(2)S oxidation such as thiosulfate, sulfite, and sulfate do not contribute to the strand cleavage process. However, initially generated oxidation products such as persulfide (S(2)(2-)) likely undergo rapid autoxidation reactions that contribute to the generation of superoxide. The potential relevance of autoxidation processes to the genotoxic and cell signaling properties of H(2)S is discussed.
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Affiliation(s)
- Marjorie Hoffman
- Department of Chemistry, University of Missouri, 125 Chemistry Building, Columbia, MO 65211, USA
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22
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The antioxidant 3H-1,2-dithiole-3-thione potentiates advanced glycation end-product-induced oxidative stress in SH-SY5Y cells. EXPERIMENTAL DIABETES RESEARCH 2012; 2012:137607. [PMID: 22675339 PMCID: PMC3362848 DOI: 10.1155/2012/137607] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/06/2011] [Revised: 02/24/2012] [Accepted: 02/26/2012] [Indexed: 01/14/2023]
Abstract
Oxidative stress is implicated as a major factor in the development of diabetes complications and is caused in part by advanced glycation end products (AGEs). AGEs ligate to the receptor for AGEs (RAGE), promoting protein kinase C (PKC)-dependent activation of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase and superoxide radical generation. While scavenging antioxidants are protective against AGEs, it is unknown if induction of endogenous antioxidant defenses has the same effect. In this study, we confirmed that the compound 3H-1,2-dithiole-3-thione (D3T) increases reduced-state glutathione (GSH) concentrations and NADPH:quinone oxidoreductase 1 (NQO1) activity in SH-SY5Y cells and provides protection against H2O2. Surprisingly, D3T potentiated oxidative damage caused by AGEs. In comparison to vehicle controls, D3T caused greater AGE-induced cytotoxicity and depletion of intracellular GSH levels while offering no protection against neurite degeneration or protein carbonylation. D3T potentiated AGE-induced reactive oxygen species (ROS) formation, an effect abrogated by inhibitors of PKC and NADPH oxidase. This study suggests that chemical induction of endogenous antioxidant defenses requires further examination in models of diabetes.
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23
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Tkachev VO, Menshchikova EB, Zenkov NK. Mechanism of the Nrf2/Keap1/ARE signaling system. BIOCHEMISTRY (MOSCOW) 2011; 76:407-22. [PMID: 21585316 DOI: 10.1134/s0006297911040031] [Citation(s) in RCA: 139] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Nrf2 regulates expression of genes containing antioxidant-respons(iv)e element (ARE) in their promoters and plays a pivotal role among all redox-sensitive transcription factors. Nrf2 is constitutively controlled by repressor protein Keap1, which acts as a molecular sensor of disturbances in cellular homeostasis. These molecular patterns are in close interconnection and function as parts of the integrated redox-sensitive signaling system Nrf2/Keap1/ARE. Depending on cellular redox balance, activity of this signaling system changes at the levels of transcription, translation, posttranslational modification, nuclear translocation of transcription factor, and its binding to ARE-driven gene promoters. This review summarizes current conceptions of Nrf2/Keap1/ARE induction and inactivation.
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Affiliation(s)
- V O Tkachev
- Scientific Center of Clinical and Experimental Medicine, Siberian Branch of the Russian Academy of Medical Sciences, Novosibirsk, Russia.
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24
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Wang L, Zhen H, Yao W, Bian F, Zhou F, Mao X, Yao P, Jin S. Lipid raft-dependent activation of dual oxidase 1/H2O2/NF-κB pathway in bronchial epithelial cells. Am J Physiol Cell Physiol 2011; 301:C171-80. [PMID: 21389273 DOI: 10.1152/ajpcell.00363.2010] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The present study addressed whether dual oxidase 1 (Duox1), a predominant isoform of NADPH oxidase in bronchial epithelial cells, is also activated through assembling of Duox1 and its partners such as p47(phox) due to lipid raft (LR) clustering. By gradient ultracentrifugation to isolate LR fractions in bronchial epithelial cells, it was found that Duox1 or p47(phox) was translocated into LR fractions when stimulated by tumor necrosis factor-α (TNF-α). Confocal microscopic analysis revealed that LRs were aggregated or clustered in the membrane, which were colocalized with Duox1 or p47(phox). Ceramide, a hydrolysis product of sphingomyelin, was also found colocalized with Duox1 or p47(phox) upon stimulation. In the presence of the commonly used LR disruptor, methyl-β-cyclodextrin (MCD), or the acid sphingomyelinase (ASMase) inhibitor, desipramine (DES), TNF-α-stimulated aggregation, translocation, and colocalization of LR components and Duox1 or its partners was abolished. Functionally, TNF-α-stimulated H(2)O(2) production was also blocked by MCD and DES (194.6 ± 15.4% vs. 90.6 ± 15.9% and 148.8 ± 20.4%), and the activation of the pivotal proinflammatory transcription factor, NF-κB, by TNF-α was reversed by MCD and DES as well as by small interfering RNAs of Duox1 or ASMase. Our results for the first time demonstrate that Duox1-mediated redox signaling in bronchial epithelial cells is associated with LR clustering dependent on the production of ceramide through ASMase.
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Affiliation(s)
- Lifen Wang
- Department of Pharmacology, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
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25
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Holland R, Fishbein JC. Chemistry of the cysteine sensors in Kelch-like ECH-associated protein 1. Antioxid Redox Signal 2010; 13:1749-61. [PMID: 20486763 PMCID: PMC2959180 DOI: 10.1089/ars.2010.3273] [Citation(s) in RCA: 86] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The protein Kelch-like ECH-associated protein 1 (Keap1) is a cysteine-rich regulatory and scaffold protein. Human Keap1 contains 27 cysteines. Some of these cysteines are believed to mediate derepression of the transcription factor nuclear factor (erythroid-derived 2)-like 2 (Nrf2), which subsequently upregulates phase 2 enzymes, in response to electrophilic/oxidative assault. Some current models depict a highly select group of two and possibly a few more cysteine residues as key sensors. The assumptions and approaches undergirding these models are commented upon. The chemical reactivity of the cysteines of Keap1 toward an array of electrophiles and one oxidant is reviewed. A number of reports in the recent literature of molecules that putatively modify cysteines of Keap1 are also included. Insights into the current molecular basis of electrophile/oxidant activation of the Nrf2 pathway via reaction at cysteines of Keap1 are discussed. Finally, important knowns and unknowns are summarized.
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Affiliation(s)
- Ryan Holland
- The Laboratory of Comparative Carcinogenesis, National Cancer Institute, National Institutes of Health, Frederick, Maryland, USA
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26
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Hayes JD, McMahon M, Chowdhry S, Dinkova-Kostova AT. Cancer chemoprevention mechanisms mediated through the Keap1-Nrf2 pathway. Antioxid Redox Signal 2010; 13:1713-48. [PMID: 20446772 DOI: 10.1089/ars.2010.3221] [Citation(s) in RCA: 412] [Impact Index Per Article: 29.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The cap'n'collar (CNC) bZIP transcription factor Nrf2 controls expression of genes for antioxidant enzymes, metal-binding proteins, drug-metabolising enzymes, drug transporters, and molecular chaperones. Many chemicals that protect against carcinogenesis induce Nrf2-target genes. These compounds are all thiol-reactive and stimulate an adaptive response to redox stress in cells. Such agents induce the expression of genes that posses an antioxidant response element (ARE) in their regulatory regions. Under normal homeostatic conditions, Nrf2 activity is restricted through a Keap1-dependent ubiquitylation by Cul3-Rbx1, which targets the CNC-bZIP transcription factor for proteasomal degradation. However, as the substrate adaptor function of Keap1 is redox-sensitive, Nrf2 protein evades ubiquitylation by Cul3-Rbx1 when cells are treated with chemopreventive agents. As a consequence, Nrf2 accumulates in the nucleus where it heterodimerizes with small Maf proteins and transactivates genes regulated through an ARE. In this review, we describe synthetic compounds and phytochemicals from edible plants that induce Nrf2-target genes. We also discuss evidence for the existence of different classes of ARE (a 16-bp 5'-TMAnnRTGABnnnGCR-3' versus an 11-bp 5'-RTGABnnnGCR-3', with or without the embedded activator protein 1-binding site 5'-TGASTCA-3'), species differences in the ARE-gene battery, and the identity of critical Cys residues in Keap1 required for de-repression of Nrf2 by chemopreventive agents.
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Affiliation(s)
- John D Hayes
- Biomedical Research Institute, Ninewells Hospital, University of Dundee, Scotland, United Kingdom.
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27
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Kensler TW, Wakabayashi N. Nrf2: friend or foe for chemoprevention? Carcinogenesis 2010; 31:90-9. [PMID: 19793802 PMCID: PMC2802668 DOI: 10.1093/carcin/bgp231] [Citation(s) in RCA: 350] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2009] [Revised: 09/16/2009] [Accepted: 09/18/2009] [Indexed: 12/16/2022] Open
Abstract
Health reflects the ability of an organism to adapt to stress. Stresses--metabolic, proteotoxic, mitotic, oxidative and DNA-damage stresses--not only contribute to the etiology of cancer and other chronic degenerative diseases but are also hallmarks of the cancer phenotype. Activation of the Kelch-like ECH-associated protein 1 (KEAP1)-NF-E2-related factor 2 (NRF2)-signaling pathway is an adaptive response to environmental and endogenous stresses and serves to render animals resistant to chemical carcinogenesis and other forms of toxicity, whilst disruption of the pathway exacerbates these outcomes. This pathway can be induced by thiol-reactive small molecules that demonstrate protective efficacy in preclinical chemoprevention models and in clinical trials. However, mutations and epigenetic modifications affecting the regulation and fate of NRF2 can lead to constitutive dominant hyperactivation of signaling that preserves rather than attenuates cancer phenotypes by providing selective resistance to stresses. This review provides a synopsis of KEAP1-NRF2 signaling, compares the impact of genetic versus pharmacologic activation and considers both the attributes and concerns of targeting the pathway in chemoprevention.
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Affiliation(s)
- Thomas W Kensler
- Department of Environmental Health Sciences, Bloomberg School of Public Health, Johns Hopkins University, 615 North Wolfe Street, Baltimore, MD 21205, USA.
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