201
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Leal AS, Wang R, Salvador JAR, Jing Y. Synthesis of novel ursolic acid heterocyclic derivatives with improved abilities of antiproliferation and induction of p53, p21waf1 and NOXA in pancreatic cancer cells. Bioorg Med Chem 2012; 20:5774-86. [PMID: 22959527 DOI: 10.1016/j.bmc.2012.08.010] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2012] [Revised: 07/18/2012] [Accepted: 08/08/2012] [Indexed: 11/25/2022]
Abstract
A series of new heterocyclic derivatives of ursolic acid 1 were synthesized and evaluated for their antiproliferative activity against AsPC-1 pancreatic cancer cells. Compounds 24-32, with an α,β unsaturated ketone in conjugation with an heterocyclic ring in ring A have improved antiproliferative activities. Compound 32 is the most active compound with an IC(50) of 1.9 μM which is sevenfold more active than ursolic acid 1. Compound 32 arrests cell cycle in G1 phase and induces apoptosis in AsPC-1 cells with upregulation of p53, p21(waf1) and NOXA protein levels.
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Affiliation(s)
- Ana S Leal
- Laboratório de Química Farmacêutica, Faculdade de Farmácia da Universidade de Coimbra, Poló das Ciências da Saúde, Azinhaga de Santa Comba, 3000-548 Coimbra, Portugal
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202
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Kim SS, Lim J, Bang Y, Gal J, Lee SU, Cho YC, Yoon G, Kang BY, Cheon SH, Choi HJ. Licochalcone E activates Nrf2/antioxidant response element signaling pathway in both neuronal and microglial cells: therapeutic relevance to neurodegenerative disease. J Nutr Biochem 2012; 23:1314-23. [DOI: 10.1016/j.jnutbio.2011.07.012] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2011] [Revised: 06/08/2011] [Accepted: 07/27/2011] [Indexed: 10/14/2022]
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203
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Karki R, Kang YR, Kim CH, Kwak KS, Kim JA, Lee ES. Hydroxychalcones as Potential Anti-Angiogenic Agent. B KOREAN CHEM SOC 2012. [DOI: 10.5012/bkcs.2012.33.9.2925] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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204
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Ma Q, He X. Molecular basis of electrophilic and oxidative defense: promises and perils of Nrf2. Pharmacol Rev 2012; 64:1055-81. [PMID: 22966037 DOI: 10.1124/pr.110.004333] [Citation(s) in RCA: 225] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Induction of drug-metabolizing enzymes through the antioxidant response element (ARE)-dependent transcription was initially implicated in chemoprevention against cancer by antioxidants. Recent progress in understanding the biology and mechanism of induction revealed a critical role of induction in cellular defense against electrophilic and oxidative stress. Induction is mediated through a novel signaling pathway via two regulatory proteins, the nuclear factor erythroid 2-related factor 2 (Nrf2) and the Kelch-like erythroid cell-derived protein with CNC homology-associated protein 1 (Keap1). Nrf2 binds to Keap1 at a two site-binding interface and is ubiquitinated by the Keap1/cullin 3/ring box protein-1-ubiquitin ligase, resulting in a rapid turnover of Nrf2 protein. Electrophiles and oxidants modify critical cysteine thiols of Keap1 and Nrf2 to inhibit Nrf2 ubiquitination, leading to Nrf2 activation and induction. Induction increases stress resistance critical for cell survival, because knockout of Nrf2 in mice increased susceptibility to a variety of toxicity and disease processes. Collateral to diverse functions of Nrf2, genome-wide search has led to the identification of a plethora of ARE-dependent genes regulated by Nrf2 in an inducer-, tissue-, and disease-dependent manner to control drug metabolism, antioxidant defense, stress response, proteasomal degradation, and cell proliferation. The protective nature of Nrf2 could also be hijacked in a number of pathological conditions by means of somatic mutation, epigenetic alteration, and accumulation of disruptor proteins, promoting drug resistance in cancer and pathologic liver features in autophagy deficiency. The repertoire of ARE inducers has expanded enormously; the therapeutic potential of the inducers has been examined beyond cancer prevention. Developing potent and specific ARE inducers and Nrf2 inhibitors holds certain new promise for the prevention and therapy against cancer, chronic disease, and toxicity.
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Affiliation(s)
- Qiang Ma
- Receptor Biology Laboratory, Toxicology and Molecular Biology Branch, Health Effects Laboratory Division, National Institute forOccupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia.
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205
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Heskes AM, Goodger JQD, Tsegay S, Quach T, Williams SJ, Woodrow IE. Localization of oleuropeyl glucose esters and a flavanone to secretory cavities of Myrtaceae. PLoS One 2012; 7:e40856. [PMID: 22911712 PMCID: PMC3401227 DOI: 10.1371/journal.pone.0040856] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2012] [Accepted: 06/14/2012] [Indexed: 01/09/2023] Open
Abstract
We report the widespread occurrence of structurally diverse oleuropeyl glucose esters, including the new diester eucaglobulin B, localized specifically to the essential oil secretory cavities of myrtaceous species. Clear taxonomic patterns in the composition of cavity extracts within the genus Eucalyptus are shown with species from subgenus Symphyomyrtus dominated by oleuropeyl glucose esters and species from subgenus Eucalyptus dominated instead by the flavanone, pinocembrin. We also examined the intra-species occurrence of oleuropeyl glucose esters by quantifying the abundant constituents cuniloside B and froggattiside A in trees from two populations of Eucalyptus polybractea R.T. Baker. All trees contained both compounds, which were positively correlated with total essential oil concentration. This apparent ubiquity of oleuropeyl glucose esters at both intra- and inter-specific levels in Eucalyptus is indicative of important physiological or ecological functions. The significance of their prevalence and the sequestration of these esters and also pinocembrin to the extracellular domain of secretory cavities is discussed in light of their potential biological activities and our findings that they are spatially segregated to the exterior of cavity lumina. The localization of oleuropeyl glucose esters to a specific and isolatable tissue type has the potential to aid in future elucidation of function and biosynthesis.
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Affiliation(s)
- Allison M Heskes
- School of Botany, The University of Melbourne, Victoria, Australia.
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206
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García-Beltrán O, González C, Pérez EG, Cassels BK, Santos JG, Millán D, Mena N, Pavez P, Aliaga ME. Nucleophilic reactivity of biothiols toward coumarin-based derivatives containing a chalcone moiety. J PHYS ORG CHEM 2012. [DOI: 10.1002/poc.2975] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Olimpo García-Beltrán
- Department of Chemistry, Faculty of Sciences; University of Chile; Santiago Chile
- Departamento de Ciencias Químicas, Facultad de Ciencias Exactas; Universidad Andrés Bello; Avenida República 275, Piso 3 Santiago Chile
| | - Christopher González
- Facultad de Química; Pontificia Universidad Católica de Chile; Av. Vicuña Mackenna 4860 Santiago 6094411 Chile
| | - Edwin G. Pérez
- Facultad de Química; Pontificia Universidad Católica de Chile; Av. Vicuña Mackenna 4860 Santiago 6094411 Chile
| | - Bruce K. Cassels
- Department of Chemistry, Faculty of Sciences; University of Chile; Santiago Chile
- Institute for Cell Dynamics and Biotechnology; University of Chile; Santiago Chile
| | - José G. Santos
- Facultad de Química; Pontificia Universidad Católica de Chile; Av. Vicuña Mackenna 4860 Santiago 6094411 Chile
| | - Daniela Millán
- Facultad de Química; Pontificia Universidad Católica de Chile; Av. Vicuña Mackenna 4860 Santiago 6094411 Chile
| | - Natalia Mena
- Department of Biology, Faculty of Sciences; University of Chile; Santiago Chile
| | - Paulina Pavez
- Facultad de Química; Pontificia Universidad Católica de Chile; Av. Vicuña Mackenna 4860 Santiago 6094411 Chile
| | - Margarita E. Aliaga
- Facultad de Química; Pontificia Universidad Católica de Chile; Av. Vicuña Mackenna 4860 Santiago 6094411 Chile
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207
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Yamamoto K, Zhou J, Hunter JJ, Williams DR, Sparrow JR. Toward an understanding of bisretinoid autofluorescence bleaching and recovery. Invest Ophthalmol Vis Sci 2012; 53:3536-44. [PMID: 22570342 DOI: 10.1167/iovs.12-9535] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE To understand molecular mechanisms underlying photobleaching of the RPE fluorophores responsible for fundus autofluorescence. METHODS ARPE-19 cells were allowed to accumulate the bisretinoid, A2E, and were irradiated at 430 nm. For some experiments, the cells were pretreated with vitamin E or sulforaphane and N-acetylcysteine; samples included A2E-free cells. The cells were analyzed by fluorescence microscopy and ultra-performance liquid chromatography-mass spectrometry (UPLC-MS) analysis. A2E free cells were also irradiated and analyzed. Cell death was quantified by double labeling with a membrane impermeable dye and 4',6'-diamino-2-phenylindole (DAPI). RESULTS A2E that had accumulated in ARPE-19 cells exhibited irradiation-associated autofluorescence bleaching despite the absence of appreciable cell death. Chromatographic analysis with absorbance, fluorescence, and mass spectrometry detection revealed that irradiation of A2E was associated with A2E photoisomerization, photooxidation, and photodegradation. Pretreatment with vitamin E favored fluorescence recovery; this finding was consistent with a process involving photooxidation. A2E that was not cell-associated underwent irradiation-induced bleaching, but fluorescence recovery was not observed. CONCLUSIONS Using cell-associated A2E as a model of RPE bisretinoid behavior, photobleaching and autofluorescence recovery was observed; these changes were similar to RPE autofluorescence reduction in vivo. The potential for autofluorescence recovery is dependent on light dose and antioxidant status. Fluorescence bleaching of bisretinoid involves photooxidative and photodegradative processes.
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Affiliation(s)
- Kazunori Yamamoto
- Department of Ophthalmology, Columbia University, New York, New York 10032, USA
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208
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Perjési P, Maász G, Reisch R, Benkő A. (E)-2-Benzylidenebenzocyclanones: Part VII. Investigation of the conjugation reaction of two cytotoxic cyclic chalcone analogues with glutathione: an HPLC–MS study. MONATSHEFTE FUR CHEMIE 2012. [DOI: 10.1007/s00706-012-0768-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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209
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Tuttle S, Hertan L, Daurio N, Porter S, Kaushick C, Li D, Myamoto S, Lin A, O'Malley BW, Koumenis C. The chemopreventive and clinically used agent curcumin sensitizes HPV (-) but not HPV (+) HNSCC to ionizing radiation, in vitro and in a mouse orthotopic model. Cancer Biol Ther 2012; 13:575-84. [PMID: 22441776 DOI: 10.4161/cbt.19772] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Radiation therapy (RT) plays a critical role in the local-regional control of head and neck squamous cell carcinoma (HNSCC). However, the efficacy of RT in treating HNSCC is limited by severe normal tissue toxicity, predominantly mucositis. One pharmacological approach for increasing the clinical response to RT is the use of radiation response modifiers that preferentially sensitize tumor cells. Previously we demonstrated that curcumin, a natural plant polyphenol, increased the radiation sensitivity of HNSCC cells and that the observed sensitization was dependent on curcumin-mediated inhibition of thioredoxin reductase 1 (TxnRd1) a key cytosolic regulator of redox-dependent signaling. Here, we examined curcumin-induced radiation sensitization in HNSCC cell lines with differing HPV status and expressing different levels of TxnRd1, in vitro. The intrinsic radiation resistance of the HPV (-) cell lines was significantly higher than the HPV (+) cell lines used in our study. Notably, all of the HPV (-) cell lines expressed high levels of TxnRd1 and exhibited higher intrinsic resistance to RT. While curcumin was effective at increasing the radiation response of the resistant HPV (-) cell lines it had no effect on the HPV (+) cells. Based on these findings we employed an orthotopic, HPV (-) HNSCC tumor model in athymic nude mice to examine the effect of combining curcumin with fractionated RT, in vivo. The combination of curcumin feeding and fractionated RT had a significant effect on tumor doubling time and overall animal survival. We therefore propose that curcumin and RT should be considered as a first line treatment of HPV (-) HNSCC.
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Affiliation(s)
- Stephen Tuttle
- Department of Radiation Oncology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
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210
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Magesh S, Chen Y, Hu L. Small molecule modulators of Keap1-Nrf2-ARE pathway as potential preventive and therapeutic agents. Med Res Rev 2012; 32:687-726. [PMID: 22549716 DOI: 10.1002/med.21257] [Citation(s) in RCA: 586] [Impact Index Per Article: 48.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Kelch-like ECH-associated protein 1 (Keap1)-nuclear factor erythroid 2-related factor 2 (Nrf2)-antioxidant response elements (ARE) pathway represents one of the most important cellular defense mechanisms against oxidative stress and xenobiotic damage. Activation of Nrf2 signaling induces the transcriptional regulation of ARE-dependent expression of various detoxifying and antioxidant defense enzymes and proteins. Keap1-Nrf2-ARE signaling has become an attractive target for the prevention and treatment of oxidative stress-related diseases and conditions including cancer, neurodegenerative, cardiovascular, metabolic, and inflammatory diseases. Over the last few decades, numerous Nrf2 inducers have been developed and some of them are currently undergoing clinical trials. Recently, overactivation of Nrf2 has been implicated in cancer progression as well as in drug resistance to cancer chemotherapy. Thus, Nrf2 inhibitors could potentially be used to improve the effectiveness of cancer therapy. Herein, we review the signaling mechanism of Keap1-Nrf2-ARE pathway, its disease relevance, and currently known classes of small molecule modulators. We also discuss several aspects of Keap1-Nrf2 interaction, Nrf2-based peptide inhibitor design, and the screening assays currently used for the discovery of direct inhibitors of Keap1-Nrf2 interaction.
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Affiliation(s)
- Sadagopan Magesh
- Department of Medicinal Chemistry, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, 160 Frelinghuysen Road, Piscataway, NJ 08854, USA
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211
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Fajardo AM, MacKenzie DA, Ji M, Deck LM, Vander Jagt DL, Thompson TA, Bisoffi M. The curcumin analog ca27 down-regulates androgen receptor through an oxidative stress mediated mechanism in human prostate cancer cells. Prostate 2012; 72:612-25. [PMID: 21796654 PMCID: PMC3309160 DOI: 10.1002/pros.21464] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/24/2011] [Accepted: 06/29/2011] [Indexed: 12/11/2022]
Abstract
BACKGROUND The androgen receptor (AR) plays a critical role in prostate cancer development and progression. Therefore, the inhibition of AR function is an established therapeutic intervention. Since the expression of the AR is retained and often increased in progressive disease, AR protein down-regulation is a promising therapeutic approach against prostate cancer. We show here that the curcumin analog 27 (ca27) down-regulates AR expression in several prostate cancer cell lines. METHODS ca27 at low micromolar concentrations was tested for its effect on AR expression, AR activation, and induction of oxidative stress in human LNCaP, C4-2, and LAPC-4 prostate cancer cells. RESULTS ca27 induced the down-regulation of AR protein expression in LNCaP, C4-2, and LAPC-4 cells within 12 hr. Further, ca27 led to the rapid induction of reactive oxygen species (ROS). To further support this finding, ca27 treatment led to the activation of the cellular redox sensor NF-E2-related factor 2 (Nrf2) and the induction of the Nrf2-regulated genes NAD(P)H quinone oxidoreductase 1 and aldoketoreductase 1C1. We show that ROS production preceded AR protein loss and that ca27-mediated down-regulation of the AR was attenuated by the antioxidant, N-acetyl cysteine. CONCLUSIONS ca27 induces ROS and mediates AR protein down-regulation through an oxidative stress mechanism of action. Our results suggest that ca27 represents a novel agent for the elucidation of mechanisms of AR down-regulation, which could lead to effective new anti-androgenic strategies for the treatment of advanced prostate cancer.
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Affiliation(s)
- Alexandra M. Fajardo
- Departmentof Biochemistry and Molecular Biology, University of New Mexico Health Sciences Center, Albuquerque, New Mexico
- Departmentof Pharmaceutical Sciences, College of Pharmacy, University of New Mexico Health Sciences Center, Albuquerque, New Mexico
| | - Debra A. MacKenzie
- Departmentof Pharmaceutical Sciences, College of Pharmacy, University of New Mexico Health Sciences Center, Albuquerque, New Mexico
| | - Ming Ji
- Departmentof Biochemistry and Molecular Biology, University of New Mexico Health Sciences Center, Albuquerque, New Mexico
| | - Lorraine M. Deck
- Departmentof Chemistry and Chemical Biology, University of New Mexico, Albuquerque, New Mexico
| | - David L. Vander Jagt
- Departmentof Biochemistry and Molecular Biology, University of New Mexico Health Sciences Center, Albuquerque, New Mexico
| | - Todd A. Thompson
- Departmentof Pharmaceutical Sciences, College of Pharmacy, University of New Mexico Health Sciences Center, Albuquerque, New Mexico
- Universityof New Mexico Cancer Center, Albuquerque, New Mexico
| | - Marco Bisoffi
- Departmentof Biochemistry and Molecular Biology, University of New Mexico Health Sciences Center, Albuquerque, New Mexico
- Universityof New Mexico Cancer Center, Albuquerque, New Mexico
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212
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Zhang Y, Ahn YH, Benjamin IJ, Honda T, Hicks RJ, Calabrese V, Cole PA, Dinkova-Kostova AT. HSF1-dependent upregulation of Hsp70 by sulfhydryl-reactive inducers of the KEAP1/NRF2/ARE pathway. ACTA ACUST UNITED AC 2012; 18:1355-61. [PMID: 22118669 DOI: 10.1016/j.chembiol.2011.09.008] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2011] [Revised: 08/31/2011] [Accepted: 09/01/2011] [Indexed: 12/14/2022]
Abstract
The KEAP1/NRF2/ARE pathway and the heat shock response are inducible cytoprotective systems regulated by transcription factors NRF2 and HSF1, respectively. We report that structurally distinct small molecule NRF2 activators, all of which react with sulfhydryl groups but differ in potency by 15,000-fold, upregulate Hsp70, a prototypic HSF1-dependent gene. Hsp70 upregulation requires HSF1 but is NRF2 independent. We further demonstrate that a sulfoxythiocarbamate inducer conjugates to the negative regulator of HSF1, Hsp90. The differential concentration dependence of the two responses suggests that activation of NRF2 precedes that of HSF1: the KEAP1/NRF2/ARE pathway is at the forefront of cellular defense, protecting against instant danger; the heat shock response closely follows to resolve subsequent potentially devastating damage, saving the proteome. This uncovered duality undoubtedly contributes to the cytoprotective effects of such molecules in models of carcinogenesis, cardiovascular disease, and neurodegeneration.
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Affiliation(s)
- Ying Zhang
- Divison of Cancer Research, Medical Research Institute, University of Dundee, Dundee DD1 9SY, Scotland, UK
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213
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Chen HH, Chen YT, Huang YW, Tsai HJ, Kuo CC. 4-Ketopinoresinol, a novel naturally occurring ARE activator, induces the Nrf2/HO-1 axis and protects against oxidative stress-induced cell injury via activation of PI3K/AKT signaling. Free Radic Biol Med 2012; 52:1054-66. [PMID: 22245092 DOI: 10.1016/j.freeradbiomed.2011.12.012] [Citation(s) in RCA: 105] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/19/2011] [Revised: 12/06/2011] [Accepted: 12/06/2011] [Indexed: 02/07/2023]
Abstract
The Nrf2/ARE pathway plays an important role in inducing phase II detoxifying enzymes and antioxidant proteins and has been considered a potential target for cancer chemoprevention because it eliminates harmful reactive oxygen species or reactive intermediates generated from carcinogens. The objectives of this study were to identify novel Nrf2/ARE activators and to investigate the mechanistic signaling pathway involved in the activation of Nrf2-mediated cytoprotective effects against oxidative-induced cell injury. A stable ARE-driven luciferase reporter cell line was established to screen a potentially cytoprotective compound. 4-Ketopinoresinol (4-KPR), the (α-γ) double-cyclized type of lignan obtained from adlay (Coix lachryma-jobi L. var. ma-yuen Stapf), activates ARE-driven luciferase activity more effectively than the classical ARE activator tert-butylhydroquinone. 4-KPR treatment resulted in a transient increase in AKT phosphorylation and subsequent phosphorylation and nuclear translocation of Nrf2, along with increased expression of ARE-dependent cytoprotective genes, such as heme oxygenase-1 (HO-1), aldo-keto reductases, and glutathione synthetic enzyme. 4-KPR suppresses oxidative stress-induced DNA damage and cell death via upregulation of HO-1. Inhibition of PI3K/AKT signaling by chemical inhibitors or RNA interference not only suppressed 4-KPR-induced Nrf2/HO-1 activation, but also eliminated the cytoprotective effect against oxidative damage. These observations in an ARE-regulated gene system suggest that 4-KPR is a novel Nrf2/ARE-mediated transcription activator, activates the Nrf2/HO-1 axis, and protects against oxidative stress-induced cell injury via activation of PI3K/AKT signaling.
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Affiliation(s)
- Huang-Hui Chen
- National Institute of Cancer Research, National Health Research Institutes, Tainan 704, Taiwan
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214
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Qin S, Chen J, Tanigawa S, Hou DX. Gene expression profiling and pathway network analysis of hepatic metabolic enzymes targeted by baicalein. JOURNAL OF ETHNOPHARMACOLOGY 2012; 140:131-140. [PMID: 22265932 DOI: 10.1016/j.jep.2011.12.046] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2011] [Accepted: 12/21/2011] [Indexed: 05/31/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Baicalein is a flavone originally isolated from the roots of traditional Chinese medicinal herb, Scutellaria baicalensis, which has been proved as a promising chemopreventive compound for many chronic human diseases. AIM OF THE STUDY The present study aimed to clarify the molecular mechanism targeted by baicalein. MATERIALS AND METHODS Gene expression profiling of HepG2 cells treated with baicalein was carried out, using the Affymetrix 42K oligonucleotide microarray in the present study. Microarray data analyzed by Ingenuity Pathway Analysis (IPA), further study performed by real time PCR, reporter gene assay, and Western blot. RESULTS Among total 42K gene probes, baicalein treatment up-regulated the signals of 440 gene probes (1.04% of total gene probes) and down-regulated signals of 254 gene probes (0.6% of total gene probes) by ≥2-fold. These genes were categorized into 35 groups and hit for biological processes, molecular functions, and signaling pathways. The network and pathway analyses of these data further revealed that an Nrf2 (nuclear factor-erythroid 2 p45-related factor 2)-mediated ARE (antioxidant response element) pathway is involved in baicalein-induced gene expression of hepatic metabolic enzymes. The representative enzymes involved in Nrf2/ARE pathway were further confirmed at mRNA level by real time PCR and at protein level by Western blot analysis. Moreover, the ARE-reporter gene assay demonstrated that baicalein stimulated Nrf2-mediated ARE transactivation. CONCLUSIONS Our results provide a comprehensive data for understanding the hepatic metabolism, bioactive role and the molecular mechanisms of baicalein.
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Affiliation(s)
- Si Qin
- Course of Biological Science and Technology, United Graduate School of Agricultural Sciences, Kagoshima University, Korimoto 1-21-24, Kagoshima 890-0065, Japan
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215
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Kim HJ, Lim JS, Kim WK, Kim JS. Soyabean glyceollins: biological effects and relevance to human health. Proc Nutr Soc 2012; 71:166-74. [PMID: 22054259 DOI: 10.1017/s0029665111003272] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Glyceollins, one family of phytoalexins, are de novo synthesised from daidzein in the soyabean upon exposure to some types of fungus. The efficiency of glyceollin production appears to be influenced by soyabean variety, fungal species, and the degree of physical damage to the soyabean. The compounds have been shown to have strong antioxidant and anti-inflammatory activities, and to inhibit the proliferation and migration of human aortic smooth muscle cells, suggesting their potential to prevent atherosclerosis. It has also been reported that glyceollins have inhibited the growth of prostate and breast cancer cells in xenograft animal models, which is probably due to their anti-oestrogenic activity. In essence, glyceollins deserve further animal and clinical studies to confirm their health benefits.
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Affiliation(s)
- Hyo Jung Kim
- School of Applied Bioscience, School of Food Science and Biotechnology, BK21 Research Team for Developing Functional Health Food Materials, Kyungpook National University, Deagu 702-701, Republic of Korea
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216
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Rojo AI, Medina-Campos ON, Rada P, Zúñiga-Toalá A, López-Gazcón A, Espada S, Pedraza-Chaverri J, Cuadrado A. Signaling pathways activated by the phytochemical nordihydroguaiaretic acid contribute to a Keap1-independent regulation of Nrf2 stability: Role of glycogen synthase kinase-3. Free Radic Biol Med 2012; 52:473-87. [PMID: 22142471 DOI: 10.1016/j.freeradbiomed.2011.11.003] [Citation(s) in RCA: 163] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/13/2011] [Revised: 11/03/2011] [Accepted: 11/04/2011] [Indexed: 01/29/2023]
Abstract
Defense against oxidative stress is executed by an antioxidant program that is tightly controlled by the transcription factor Nrf2. The stability of Nrf2 involves the interaction of two degradation domains, designated Neh2 and Neh6, with the E3 ubiquitin ligase adaptors, Keap1 and β-TrCP, respectively. The regulation of Nrf2 through the Neh6 degron remains largely unexplored but requires GSK-3 to form a phosphodegron. In this study, the cancer-chemopreventive agent nordihydroguaiaretic acid (NDGA) increased the level of Nrf2 protein and expression of heme oxygenase-1 (HO-1) in kidney-derived LLC-PK1 and HEK293T cells and in wild-type mouse embryo fibroblasts (MEFs). However, NDGA did not induce HO-1 in Nrf2(-/-) MEFs, indicating that Nrf2 is required for induction. The relevance of the Nrf2/HO-1 axis to antioxidant protection was further demonstrated by the finding that the HO-1 inhibitor stannous-mesoporphyrin abolished protection against hydrogen peroxide conferred by NDGA. NDGA increased Nrf2 and HO-1 protein levels in Keap1(-/-) MEFs, implying that Keap1-independent mechanisms regulate Nrf2 stability. Mutants of the Neh2 or Nrh6 domain and chimeric proteins comprising cyan fluorescent protein fused to Neh2 and green fluorescent protein fused to Neh6 exhibited longer half-lives in the presence of NDGA, demonstrating that NDGA targets both the Neh2 and the Neh6 degrons. In common with other chemopreventive agents, NDGA activated the ERK1/2, p38, JNK, and PI3K pathways. By using selective kinase inhibitors we found that PI3K, JNK, and p38 were responsible for the stabilization of Nrf2 and induction of HO-1 by NDGA. To explain how NDGA might up-regulate Nrf2 in a Keap1-independent manner we explored the participation of GSK-3β because it controls the Neh6 phosphodegron. Importantly, NDGA caused inhibitory phosphorylation of GSK-3β at Ser9 and at Thr390, and this was associated with a substantial reduction in Neh6 phosphorylation. Our study demonstrates that NDGA activates Nrf2 through multiple signaling cascades and identifies GSK-3β as an integrator of these signaling pathways and a gatekeeper of Nrf2 stability at the level of the Neh6 phosphodegron.
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Affiliation(s)
- Ana I Rojo
- Departamento de Bioquímica e Instituto de Investigaciones Biomédicas Alberto Sols UAM-CSIC, Centro de Investigación en Red Sobre Enfermedades Neurodegenerativas, Instituto de Investigación Sanitaria la Paz, Madrid 28029, Spain
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Small-molecule proteostasis regulators for protein conformational diseases. Nat Chem Biol 2011; 8:185-96. [PMID: 22198733 PMCID: PMC3262058 DOI: 10.1038/nchembio.763] [Citation(s) in RCA: 163] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2011] [Accepted: 10/14/2011] [Indexed: 12/24/2022]
Abstract
Protein homeostasis (proteostasis) is essential for cellular and organismal health. Stress, aging, and the chronic expression of misfolded proteins, however, challenge the proteostasis machinery and the vitality of the cell. Enhanced expression of molecular chaperones, regulated by heat shock transcription factor-1 (HSF-1), has been shown to restore proteostasis in a variety of conformational disease models, suggesting a promising therapeutic approach. We describe the results of a ∼900,000 small molecule screen that identified novel classes of small molecule proteostasis regulators (PRs) that induce HSF-1-dependent chaperone expression and restore protein folding in multiple conformational disease models. The beneficial effects to proteome stability are mediated by HSF-1, DAF-16/FOXO, SKN-1/Nrf-2, and the chaperone machinery through mechanisms that are distinct from current known small molecule activators of the HSR. We suggest that modulation of the proteostasis network by PRs represents a promising therapeutic approach for the treatment of a variety of protein conformational diseases.
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218
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Modulation of oxidative stress and mitochondrial function by the ketogenic diet. Epilepsy Res 2011; 100:295-303. [PMID: 22078747 DOI: 10.1016/j.eplepsyres.2011.09.021] [Citation(s) in RCA: 105] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2011] [Revised: 08/17/2011] [Accepted: 09/07/2011] [Indexed: 12/23/2022]
Abstract
The ketogenic diet (KD) is a high-fat, low carbohydrate diet that is used as a therapy for intractable epilepsy. However, the mechanism(s) by which the KD achieves neuroprotection and/or seizure control are not yet known. The broad efficacy of the KD in diverse epilepsies coupled with its profound influence on metabolism suggests that mitochondrial functions may be critical in its mechanism(s) of seizure control. Mitochondria subserve important cellular functions that include the production of cellular ATP, control of apoptosis, maintenance of calcium homeostasis and the production and elimination of reactive oxygen species (ROS). This review will focus on recent literature reporting the regulation of mitochondrial functions and redox signaling by the KD. The review highlights a potential mechanism of the KD involving the production of low levels of redox signaling molecules such as H(2)O(2) and electrophiles e.g. 4-hydroxynonenal (4-HNE), which in turn activate adaptive pathways such as the protective transcription factor, NF E2-related factor 2 (Nrf2). This can ultimately result in increased production of antioxidants (e.g. GSH) and detoxification enzymes which may be critical in mediating the protective effects of the KD.
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Calabrese V, Cornelius C, Dinkova-Kostova AT, Iavicoli I, Di Paola R, Koverech A, Cuzzocrea S, Rizzarelli E, Calabrese EJ. Cellular stress responses, hormetic phytochemicals and vitagenes in aging and longevity. Biochim Biophys Acta Mol Basis Dis 2011; 1822:753-83. [PMID: 22108204 DOI: 10.1016/j.bbadis.2011.11.002] [Citation(s) in RCA: 280] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2011] [Revised: 10/31/2011] [Accepted: 11/01/2011] [Indexed: 12/30/2022]
Abstract
Modulation of endogenous cellular defense mechanisms represents an innovative approach to therapeutic intervention in diseases causing chronic tissue damage, such as in neurodegeneration. This paper introduces the emerging role of exogenous molecules in hormetic-based neuroprotection and the mitochondrial redox signaling concept of hormesis and its applications to the field of neuroprotection and longevity. Maintenance of optimal long-term health conditions is accomplished by a complex network of longevity assurance processes that are controlled by vitagenes, a group of genes involved in preserving cellular homeostasis during stressful conditions. Vitagenes encode for heat shock proteins (Hsp) Hsp32, Hsp70, the thioredoxin and the sirtuin protein systems. Dietary antioxidants, such as polyphenols and L-carnitine/acetyl-L-carnitine, have recently been demonstrated to be neuroprotective through the activation of hormetic pathways, including vitagenes. Hormesis provides the central underpinning of neuroprotective responses, providing a framework for explaining the common quantitative features of their dose response relationships, their mechanistic foundations, their relationship to the concept of biological plasticity as well as providing a key insight for improving the accuracy of the therapeutic dose of pharmaceutical agents within the highly heterogeneous human population. This paper describes in mechanistic detail how hormetic dose responses are mediated for endogenous cellular defense pathways including sirtuin, Nrfs and related pathways that integrate adaptive stress responses in the prevention of neurodegenerative diseases. This article is part of a Special Issue entitled: Antioxidants and Antioxidant Treatment in Disease.
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Brigelius-Flohé R, Flohé L. Basic principles and emerging concepts in the redox control of transcription factors. Antioxid Redox Signal 2011; 15:2335-81. [PMID: 21194351 PMCID: PMC3166203 DOI: 10.1089/ars.2010.3534] [Citation(s) in RCA: 416] [Impact Index Per Article: 32.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Convincing concepts of redox control of gene transcription have been worked out for prokaryotes and lower eukaryotes, whereas the knowledge on complex mammalian systems still resembles a patchwork of poorly connected findings. The article, therefore, reviews principles of redox regulation with special emphasis on chemical feasibility, kinetic requirements, specificity, and physiological context, taking well investigated mammalian transcription factor systems, nuclear transcription factor of bone marrow-derived lymphocytes (NF-κB), and kelch-like ECH-associated protein-1 (Keap1)/Nrf2, as paradigms. Major conclusions are that (i) direct signaling by free radicals is restricted to O(2)•- and •NO and can be excluded for fast reacting radicals such as •OH, •OR, or Cl•; (ii) oxidant signals are H(2)O(2), enzymatically generated lipid hydroperoxides, and peroxynitrite; (iii) free radical damage is sensed via generation of Michael acceptors; (iv) protein thiol oxidation/alkylation is the prominent mechanism to modulate function; (v) redox sensors must be thiol peroxidases by themselves or proteins with similarly reactive cysteine or selenocysteine (Sec) residues to kinetically compete with glutathione peroxidase (GPx)- and peroxiredoxin (Prx)-type peroxidases or glutathione-S-transferases, respectively, a postulate that still has to be verified for putative mammalian sensors. S-transferases and Prxs are considered for system complementation. The impact of NF-κB and Nrf2 on hormesis, management of inflammatory diseases, and cancer prevention is critically discussed.
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Affiliation(s)
- Regina Brigelius-Flohé
- Department Biochemistry of Micronutrients, German Institute of Human Nutrition Potsdam-Rehbruecke, Arthur-Scheunert-Allee 114-116, Nuthetal, Germany.
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Pan L, Wu X, Zhao D, Hessari NM, Lee I, Zhang X, Xu J. Sulfhydryl modification induces calcium entry through IP₃-sensitive store-operated pathway in activation-dependent human neutrophils. PLoS One 2011; 6:e25262. [PMID: 21984909 PMCID: PMC3184953 DOI: 10.1371/journal.pone.0025262] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2011] [Accepted: 08/30/2011] [Indexed: 11/23/2022] Open
Abstract
As the first line of host defense, neutrophils are stimulated by pro-inflammatory cytokines from resting state, facilitating the execution of immunomodulatory functions in activation state. Sulfhydryl modification has a regulatory role in a wide variety of physiological functions through mediation of signaling transductions in various cell types. Recent research suggested that two kinds of sulfhydryl modification, S-nitrosylation by exogenous nitric oxide (NO) and alkylation by N-ethylmaleimide (NEM), could induce calcium entry through a non-store-operated pathway in resting rat neutrophils and DDT1MF-2 cells, while in active human neutrophils a different process has been observed by us. In the present work, data showed that NEM induced a sharp rising of cytosolic calcium concentration ([Ca2+]c) without external calcium, followed by a second [Ca2+]c increase with readdition of external calcium in phorbol 12-myristate 13-acetate (PMA)-activated human neutrophils. Meanwhile, addition of external calcium did not cause [Ca2+]c change of Ca2+-free PMA-activated neutrophils before application of NEM. These data indicated that NEM could induce believable store-operated calcium entry (SOCE) in PMA-activated neutrophils. Besides, we found that sodium nitroprusside (SNP), a donor of exogenous NO, resulted in believable SOCE in PMA-activated human neutrophils via S-nitrosylation modification. In contrast, NEM and SNP have no effect on [Ca2+]c of resting neutrophils which were performed in suspension. Furthermore, 2-Aminoethoxydiphenyl borate, a reliable blocker of SOCE and an inhibitor of inositol 1,4,5-trisphosphate (IP3) receptor, evidently abolished SNP and NEM-induced calcium entry at 75 µM, while preventing calcium release in a concentration-dependent manner. Considered together, these results demonstrated that NEM and SNP induced calcium entry through an IP3-sensitive store-operated pathway of human neutrophils via sulfhydryl modification in a PMA-induced activation-dependent manner.
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Affiliation(s)
- Leiting Pan
- The MOE Key Laboratory of Weak-Light Nonlinear Photonics, TEDA Applied Physics School and School of Physics, Nankai University, Tianjin, People's Republic of China.
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Scapagnini G, Vasto S, Sonya V, Abraham NG, Nader AG, Caruso C, Calogero C, Zella D, Fabio G. Modulation of Nrf2/ARE pathway by food polyphenols: a nutritional neuroprotective strategy for cognitive and neurodegenerative disorders. Mol Neurobiol 2011; 44:192-201. [PMID: 21499987 PMCID: PMC5554938 DOI: 10.1007/s12035-011-8181-5] [Citation(s) in RCA: 276] [Impact Index Per Article: 21.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2010] [Accepted: 04/04/2011] [Indexed: 12/21/2022]
Abstract
In recent years, there has been a growing interest, supported by a large number of experimental and epidemiological studies, for the beneficial effects of some phenolic substances, contained in commonly used spices and herbs, in preventing various age-related pathologic conditions, ranging from cancer to neurodegenerative diseases. Although the exact mechanisms by which polyphenols promote these effects remain to be elucidated, several reports have shown their ability to stimulate a general xenobiotic response in the target cells, activating multiple defense genes. Data from our and other laboratories have previously demonstrated that curcumin, the yellow pigment of curry, strongly induces heme-oxygenase-1 (HO-1) expression and activity in different brain cells via the activation of heterodimers of NF-E2-related factors 2 (Nrf2)/antioxidant responsive element (ARE) pathway. Many studies clearly demonstrate that activation ofNrf2 target genes, and particularly HO-1, in astrocytes and neurons is strongly protective against inflammation, oxidative damage, and cell death. In the central nervous system, the HO system has been reported to be very active, and its modulation seems to play a crucial role in the pathogenesis of neurodegenerative disorders. Recent and unpublished data from our group revealed that low concentrations of epigallocatechin-3-gallate, the major green tea catechin, induces HO-1 by ARE/Nrf2 pathway in hippocampal neurons, and by this induction, it is able to protect neurons against different models of oxidative damages. Furthermore, we have demonstrated that other phenolics, such as caffeic acid phenethyl ester and ethyl ferulate, are also able to protect neurons via HO-1 induction. These studies identify a novel class of compounds that could be used for therapeutic purposes as preventive agents against cognitive decline.
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223
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Zhao L, Lee JY, Hwang DH. Inhibition of pattern recognition receptor-mediated inflammation by bioactive phytochemicals. Nutr Rev 2011; 69:310-20. [PMID: 21631512 DOI: 10.1111/j.1753-4887.2011.00394.x] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Emerging evidence reveals that pattern-recognition receptors (PRRs), Toll-like receptors (TLRs), and nucleotide-binding oligomerization domain proteins (NODs) mediate both infection-induced and sterile inflammation by recognizing pathogen-associated molecular patterns and endogenous molecules, respectively. PRR-mediated chronic inflammation is a determinant for the development and progression of chronic diseases including cancer, atherosclerosis, and insulin resistance. Recent studies demonstrated that certain phytochemicals inhibit PRR-mediated pro-inflammation. Curcumin, helenalin, and cinnamaldehyde with α, β-unsaturated carbonyl groups, or sulforaphane with an isothiocyanate group, inhibit TLR4 activation by interfering with cysteine residue-mediated receptor dimerization, while resveratrol, with no unsaturated carbonyl group, did not. Similarly, curcumin, parthenolide, and helenalin, but not resveratrol and (-)-epigallocatechin-3-gallate (EGCG), also inhibit NOD2 activation by interfering with NOD2 dimerization. In contrast, resveratrol, EGCG, luteolin, and structural analogs of luteolin specifically inhibit TLR3 and TLR4 signaling by targeting TANK binding kinase 1 (TBK1) and receptor interacting protein 1 (RIP1) in Toll/IL-1 receptor domain-containing adaptor inducing IFN-β (TRIF) complex. Together, these results suggest that PRRs and downstream signaling components are molecular targets for dietary strategies to reduce PRR-mediated chronic inflammation and consequent risks of chronic diseases.
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Affiliation(s)
- Ling Zhao
- Department of Nutrition, The University of Tennessee, Knoxville, Tennessee, USA
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224
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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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225
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Shin DH, Seo EY, Pang B, Nam JH, Kim HS, Kim WK, Kim SJ. Inhibition of Ca2+-release-activated Ca2+ channel (CRAC) and K+ channels by curcumin in Jurkat-T cells. J Pharmacol Sci 2011; 115:144-154. [PMID: 21343666 DOI: 10.1254/jphs.10209fp] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2010] [Accepted: 12/01/2010] [Indexed: 10/18/2022] Open
Abstract
The increase in cytoplasmic Ca(2+) concentration (Δ[Ca(2+)](c)) mediated by the Ca(2+)-release-activated Ca(2+) channel (CRAC) is a critical signal for the activation of lymphocytes. Also, the voltage-gated K(+) channel (K(v)) and intermediate-conductance Ca(2+)-activated K(+) channel (IKCa1/SK4) have drawn attention as pharmacological targets for regulating immune responses. Since polyphenolic agents have various immunomodulatory effects, here we compared the effects of curcumin, rosmarinic acid, resveratrol, and epigallocatechin gallate on the ionic currents through CRAC (I(CRAC)), K(v) (I(Kv)), SK4 (I(SK4)) and on the Δ[Ca(2+)](c) of Jurkat-T cells using the patch clamp technique and fura-2 spectrofluorimetry. Curcumin (10 µM) inhibited store-operated Ca(2+) entry (SOCE). Consistently, dose-dependent inhibition of I(CRAC) by curcumin was confirmed in Jurkat-T (IC(50), 5.9 µM) and the HEK293 cells overexpressing Orai1 and STIM1 (IC(50), 0.6 µM). Also, curcumin inhibited both I(Kv) (IC(50), 11.9 µM) and I(SK4) (IC(50), 4.2 µM). The other polyphenols (rosmarinic acid, resveratrol, and epigallocatechin gallate at 10 - 30 µM) had no effect on SOCE and showed only a partial inhibition of the K(+) currents. In summary, among the tested polyphenolic agents, curcumin showed prominent inhibition of major ion channels in lymphocytes, which might contribute to the anti-inflammatory effects of curcumin. [Supplementary Figures: available only at http://dx.doi.org/10.1254/jphs.10209FP].
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Affiliation(s)
- Dong Hoon Shin
- Department of Physiology, Seoul National University College of Medicine, Seoul 110-799, Korea
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Turpaev K, Ermolenko M, Cresteil T, Drapier JC. Benzylidenemalononitrile compounds as activators of cell resistance to oxidative stress and modulators of multiple signaling pathways. A structure–activity relationship study. Biochem Pharmacol 2011; 82:535-47. [DOI: 10.1016/j.bcp.2011.05.028] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2011] [Revised: 05/24/2011] [Accepted: 05/25/2011] [Indexed: 10/18/2022]
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Higgins LG, Hayes JD. Mechanisms of induction of cytosolic and microsomal glutathione transferase (GST) genes by xenobiotics and pro-inflammatory agents. Drug Metab Rev 2011; 43:92-137. [PMID: 21495793 DOI: 10.3109/03602532.2011.567391] [Citation(s) in RCA: 138] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Glutathione transferase (GST) isoezymes are encoded by three separate families of genes (designated cytosolic, microsomal and mitochondrial transferases), with distinct evolutionary origins, that provide mammalian species with protection against electrophiles and oxidative stressors in the environment. Members of the cytosolic class Alpha, Mu, Pi and Theta GST, and also certain microsomal transferases (MGST2 and MGST3), are up-regulated by a diverse spectrum of foreign compounds typified by phenobarbital, 1,4-bis[2-(3,5-dichloropyridyloxy)]benzene, pregnenolone-16α-carbonitrile, 3-methylcholanthrene, 2,3,7,8-tetrachloro-dibenzo-p-dioxin, β-naphthoflavone, butylated hydroxyanisole, ethoxyquin, oltipraz, fumaric acid, sulforaphane, coumarin, 1-[2-cyano-3,12-dioxooleana-1,9(11)-dien-28-oyl]imidazole, 12-O-tetradecanoylphorbol-13-acetate, dexamethasone and thiazolidinediones. Collectively, these compounds induce gene expression through the constitutive androstane receptor (CAR), the pregnane X receptor (PXR), the aryl hydrocarbon receptor (AhR), NF-E2-related factor 2 (Nrf2), peroxisome proliferator-activated receptor-γ (PPARγ) and CAATT/enhancer binding protein (C/EBP) β. The microsomal T family includes 5-lipoxygenase activating protein (FLAP), leukotriene C(4) synthase (LTC4S) and prostaglandin E(2) synthase (PGES-1), and these are up-regulated by tumour necrosis factor-α, lipopolysaccharide and transforming growth factor-β. Induction of genes encoding FLAP, LTC4S and PGES-1 is mediated by the transcription factors C/EBPα, C/EBPδ, C/EBPϵ, nuclear factor-κB and early growth response-1. In this article we have reviewed the literature describing the mechanisms by which cytosolic and microsomal GST are up-regulated by xenobiotics, drugs, cytokines and endotoxin. We discuss cross-talk between the different induction mechanisms, and have employed bioinformatics to identify cis-elements in the upstream regions of GST genes to which the various transcription factors mentioned above may be recruited.
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Affiliation(s)
- Larry G Higgins
- Biomedical Research Institute, Ninewells Hospital and Medical School, University of Dundee, Dundee DD1 9SY, Scotland, United Kingdom
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Drakulić BJ, Stanojković TP, Žižak ŽS, Dabović MM. Antiproliferative activity of aroylacrylic acids. Structure-activity study based on molecular interaction fields. Eur J Med Chem 2011; 46:3265-73. [DOI: 10.1016/j.ejmech.2011.04.043] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2011] [Revised: 04/09/2011] [Accepted: 04/13/2011] [Indexed: 11/26/2022]
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Budhiraja A, Kadian K, Kaur M, Aggarwal V, Garg A, Sapra S, Nepali K, Suri OP, Dhar KL. Synthesis and biological evaluation of naphthalene, furan and pyrrole based chalcones as cytotoxic and antimicrobial agents. Med Chem Res 2011. [DOI: 10.1007/s00044-011-9733-y] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Abstract
BACKGROUND The nuclear transcription factor NF-κB has gained considerable importance due to its major involvement in inflammation and constitutive activity in malignant cells. It is induced by a variety of stimuli and controls the expression of several proteins involved in biological processes. Numerous natural products and synthesized organic molecules have been reported to inhibit NF-κB and have played an integral role in identifying implicated pathways. Prominent among them are the sesquiterpene lactones, polyphenolic enones and other α,β-unsaturated carbonyl-containing molecules, particularly α-methylene-γ-butyrolactones. DISCUSSION This mini-review provides an introductory overview of some of the associated pathways involving NF-κB in cancer and discusses the structures and mode of action of natural α,β-unsaturated carbonyl-containing inhibitors and their synthetic counterparts. A review of the recent methods for the synthesis of α-alkylidene-γ-butyrolactones is also provided, with the aim of arousing the interest of synthetic chemists for the design and development of novel NF-κB inhibitors. CONCLUSIONS Modulating damaging effects without harming the inflammatory and immune responses are crucial parameters for developing NF-κB inhibitors. Examination of novel α,β-unsaturated carbonyls and the further discovery of simple methods to prepare such molecules should lead to the identification of site-specific inhibitors.
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Isolation of quinone reductase (QR) inducing agents from ginger rhizome and their in vitro anti-inflammatory activity. Food Res Int 2011. [DOI: 10.1016/j.foodres.2011.04.010] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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232
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Overmeyer JH, Young AM, Bhanot H, Maltese WA. A chalcone-related small molecule that induces methuosis, a novel form of non-apoptotic cell death, in glioblastoma cells. Mol Cancer 2011; 10:69. [PMID: 21639944 PMCID: PMC3118192 DOI: 10.1186/1476-4598-10-69] [Citation(s) in RCA: 119] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2011] [Accepted: 06/06/2011] [Indexed: 01/19/2023] Open
Abstract
Background Methuosis is a unique form of non-apoptotic cell death triggered by alterations in the trafficking of clathrin-independent endosomes, ultimately leading to extreme vacuolization and rupture of the cell. Results Here we describe a novel chalcone-like molecule, 3-(2-methyl-1H- indol-3-yl)-1-(4-pyridinyl)-2-propen-1-one (MIPP) that induces cell death with the hallmarks of methuosis. MIPP causes rapid accumulation of vacuoles derived from macropinosomes, based on time-lapse microscopy and labeling with extracellular fluid phase tracers. Vacuolization can be blocked by the cholesterol-interacting compound, filipin, consistent with the origin of the vacuoles from non-clathrin endocytic compartments. Although the vacuoles rapidly acquire some characteristics of late endosomes (Rab7, LAMP1), they remain distinct from lysosomal and autophagosomal compartments, suggestive of a block at the late endosome/lysosome boundary. MIPP appears to target steps in the endosomal trafficking pathway involving Rab5 and Rab7, as evidenced by changes in the activation states of these GTPases. These effects are specific, as other GTPases (Rac1, Arf6) are unaffected by the compound. Cells treated with MIPP lose viability within 2-3 days, but their nuclei show no evidence of apoptotic changes. Inhibition of caspase activity does not protect the cells, consistent with a non-apoptotic death mechanism. U251 glioblastoma cells selected for temozolomide resistance showed sensitivity to MIPP-induced methuosis that was comparable to the parental cell line. Conclusions MIPP might serve as a prototype for new drugs that could be used to induce non-apoptotic death in cancers that have become refractory to agents that work through DNA damage and apoptotic mechanisms.
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Affiliation(s)
- Jean H Overmeyer
- Department of Biochemistry and Cancer Biology, University of Toledo College of Medicine, Toledo, Ohio, USA
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Anwar-Mohamed A, Degenhardt OS, El Gendy MA, Seubert JM, Kleeberger SR, El-Kadi AO. The effect of Nrf2 knockout on the constitutive expression of drug metabolizing enzymes and transporters in C57Bl/6 mice livers. Toxicol In Vitro 2011; 25:785-95. [DOI: 10.1016/j.tiv.2011.01.014] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2010] [Revised: 01/13/2011] [Accepted: 01/24/2011] [Indexed: 01/06/2023]
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Affiliation(s)
- Pratim Kumar Chattaraj
- Department of Chemistry, Center for Theoretical Studies, Indian Institute of Technology, Kharagpur, India
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235
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Abstract
Curcumin, a hydrophobic polyphenol derived from rhizome (turmeric) of the herbCurcuma longa, have been shown to exhibit antioxidant, anticarcinogenic anti-inflammatory, antimicrobial and nephroprotective activities,et al. Among these, its potent antioxidant activity is worthwhile of special attention, because oxidative stress is involved in the pathogenesis of cancer, neurodegenerative diseases,et al. This review focuses on the ways that curcumin exerts its antioxidant activity, including direct chemical reaction with free radicals, chelation with metals ions which results in oxidative stress, regulation of antioxidant-related enzyme activity and gene expression. Meanwhile the disputed chemical antioxidant mechanism is also discussed.
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Kim HJ, di Luccio E, Kong ANT, Kim JS. Nrf2-mediated induction of phase 2 detoxifying enzymes by glyceollins derived from soybean exposed to Aspergillus sojae. Biotechnol J 2011; 6:525-36. [PMID: 21538894 DOI: 10.1002/biot.201100010] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2023]
Abstract
Numerous antioxidants have been reported to cause transcriptional activation of several antioxidant enzymes through binding antioxidant-response element on their promoter region. We, therefore, attempted to examine whether glyceollins, which share common structural features with many phase 2 enzyme inducers and antioxidant activity, could induce detoxifying/antioxidant enzymes. Glyceollins induced NAD(P)H:quinone oxidoreductase activity in a dose-dependent manner in both mouse hepatoma Hepa1c1c7 and its mutant BPRc1 cells. The compounds also increased the expression of some representative antioxidant enzymes, such as heme oxygenase 1,gamma-glutamylcysteine synthase, and glutathione reductase, by promoting nuclear translocation of the NF-E2-related factor-2 (Nrf2). Furthermore, phosphorylation of Akt and antioxidant response element-mediated reporter gene expression were enhanced by glyceollins but suppressed by LY294002, an inhibitor of phosphoinositide 3-kinases (PI3K). This suggests that glyceollins may cause Nrf2-mediated phase 2 enzyme induction through activation of the PI3K signaling pathway as well as interaction with Keap1. Our molecular docking simulations also suggest that the glyceollin isomers tightly bind into the binding pocket around Cys151, preventing Nrf2 from docking to Keap1. In conclusion, the current data suggest that glyceollins induced phase 2 detoxifying enzymes likely through promoting nuclear translocation of Nrf2, which is known to be regulated by phosphorylation of Nrf2 and/or disrupting Keap1-Nrf2 complex formation.
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Affiliation(s)
- Hyo Jung Kim
- School of Applied Biosciences, Kyungpook National University, Daegu, Republic of Korea
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Shearn CT, Fritz KS, Thompson JA. Protein damage from electrophiles and oxidants in lungs of mice chronically exposed to the tumor promoter butylated hydroxytoluene. Chem Biol Interact 2011; 192:278-86. [PMID: 21536018 DOI: 10.1016/j.cbi.2011.04.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2010] [Revised: 04/15/2011] [Accepted: 04/16/2011] [Indexed: 11/16/2022]
Abstract
The food additive butylated hydroxytoluene (BHT) promotes tumorigenesis in mouse lung. Chronic BHT exposure is accompanied by pulmonary inflammation and several studies indicate that elevated levels of reactive oxygen species (ROS) are involved in its promoting activity. The link between BHT and elevated ROS involves formation of quinone methide (QM) metabolites; these electrophiles form adducts with a variety of lung proteins including several enzymes that protect cells from oxidative stress. Studies in vitro demonstrated that QM alkylation of cytoprotective enzymes is accompanied by inactivation, so an objective of the present investigation was to determine if inactivation also occurs in vivo. Two groups of mice were exposed to BHT by intraperitoneal injection, one for 10 days and the other for 24 days, and proteins from lung cytosols were examined for damage. Analysis by Western blotting demonstrated that BHT treatment caused substantial increases in protein carbonylation, nitration and adduction by 4-hydroxynonenal, confirming the occurrence of sustained oxidative and nitrosative stress over the treatment period required for tumor promotion. Effects of BHT on the activities and/or levels of a representative group of antioxidant/protective enzymes in mouse lung also were assessed; NAD(P)H:quinone reductase and glutathione reductase were unaffected, however carbonyl reductase activity decreased 50-60%. Superoxide dismutase and glutathione peroxidase activities increased 2- and 1.5-fold, respectively, and glutamate-cysteine ligase catalytic subunit expression increased 32-39% relative to untreated mice. Glutathione S-transferase (GST) activity decreased 50-60% but concentrations of the predominant isoforms, GSTM1 and P1, were not affected. GSTP1 was substantially more susceptible than M1 to adduction and inhibition by treatment with BHT-QM in vitro, suggesting that lower GST activity in mice after BHT treatment is due to adduction of the P1 isoform. The results of this study provide additional insight into mechanisms of BHT-induced oxidative damage and further support a link between inflammation and tumor promotion in mouse lung.
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Affiliation(s)
- Colin T Shearn
- Department of Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, 12850 E. Montview Blvd., Aurora, CO 80045, USA
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238
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Baird L, Dinkova-Kostova AT. The cytoprotective role of the Keap1-Nrf2 pathway. Arch Toxicol 2011; 85:241-72. [PMID: 21365312 DOI: 10.1007/s00204-011-0674-5] [Citation(s) in RCA: 723] [Impact Index Per Article: 55.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2010] [Accepted: 02/08/2011] [Indexed: 12/11/2022]
Abstract
An elaborate network of highly inducible proteins protects aerobic cells against the cumulative damaging effects of reactive oxygen intermediates and toxic electrophiles, which are the major causes of neoplastic and chronic degenerative diseases. These cytoprotective proteins share common transcriptional regulation, through the Keap1-Nrf2 pathway, which can be activated by various exogenous and endogenous small molecules (inducers). Inducers chemically react with critical cysteine residues of the sensor protein Keap1, leading to stabilisation and nuclear translocation of transcription factor Nrf2, and ultimately to coordinate enhanced expression of genes coding for cytoprotective proteins. In addition, inducers inhibit pro-inflammatory responses, and there is a linear correlation spanning more than six orders of magnitude of concentrations between inducer and anti-inflammatory activity. Genetic deletion of transcription factor Nrf2 renders cells and animals much more sensitive to the damaging effects of electrophiles, oxidants and inflammatory agents in comparison with their wild-type counterparts. Conversely, activation of the Keap1-Nrf2 pathway allows survival and adaptation under various conditions of stress and has protective effects in many animal models. Cross-talks with other signalling pathways broadens the role of the Keap1-Nrf2 pathway in determining the fate of the cell, impacting fundamental biological processes such as proliferation, apoptosis, angiogenesis and metastasis.
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Affiliation(s)
- Liam Baird
- Biomedical Research Institute, University of Dundee, Dundee, Scotland, UK
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239
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Sporn MB, Liby KT, Yore MM, Fu L, Lopchuk JM, Gribble GW. New synthetic triterpenoids: potent agents for prevention and treatment of tissue injury caused by inflammatory and oxidative stress. JOURNAL OF NATURAL PRODUCTS 2011; 74:537-45. [PMID: 21309592 PMCID: PMC3064114 DOI: 10.1021/np100826q] [Citation(s) in RCA: 241] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
We review the original rationale for the development and the chemistry of a series of new synthetic oleanane triterpenoids (SO), based on oleanolic acid (1) as a starting material. Many of the new compounds that have been made, such as 2-cyano-3,12-dioxooleana-1,9(11)-dien-28-oic acid ("CDDO", 8), are highly potent (activities found at levels below 1 nM) anti-inflammatory agents, as measured by their ability to block the cellular synthesis of the enzyme inducible nitric oxide synthase (iNOS) in activated macrophages. Details of the organic synthesis of new SO and their chemical mechanisms of biological activity are reviewed, as is formation of biotin conjugates for investigation of protein targets. Finally, we give a brief summary of important biological activities of SO in many organ systems in numerous animal models. Clinical investigation of a new SO (methyl 2-cyano-3,12-dioxooleana-1,9(11)dien-28-oate, "CDDO-Me", bardoxolone methyl, 13) is currently in progress.
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Affiliation(s)
- Michael B. Sporn
- Departments of Pharmacology and Medicine, Dartmouth Medical School, Hanover, New Hampshire 03755, United States
- Tel: (603) 650-6557. Fax: (603) 650-1129. E-mail: . Tel: (603) 646-3118. E-mail:
| | - Karen T. Liby
- Departments of Pharmacology and Medicine, Dartmouth Medical School, Hanover, New Hampshire 03755, United States
| | - Mark M. Yore
- Departments of Pharmacology and Medicine, Dartmouth Medical School, Hanover, New Hampshire 03755, United States
| | - Liangfeng Fu
- Department of Chemistry, Dartmouth College, Hanover, New Hampshire 03755, United States
| | - Justin M. Lopchuk
- Department of Chemistry, Dartmouth College, Hanover, New Hampshire 03755, United States
| | - Gordon W. Gribble
- Department of Chemistry, Dartmouth College, Hanover, New Hampshire 03755, United States
- Tel: (603) 650-6557. Fax: (603) 650-1129. E-mail: . Tel: (603) 646-3118. E-mail:
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240
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Shin JW, Ohnishi K, Murakami A, Lee JS, Kundu JK, Na HK, Ohigashi H, Surh YJ. Zerumbone induces heme oxygenase-1 expression in mouse skin and cultured murine epidermal cells through activation of Nrf2. Cancer Prev Res (Phila) 2011; 4:860-70. [PMID: 21367956 DOI: 10.1158/1940-6207.capr-10-0354] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Zerumbone, a sesquiterpene derived from tropical ginger, contains an electrophilic α,β-unsaturated carbonyl moiety and was found to suppress chemically induced papilloma formation in mouse skin. Here, we report that topical application of zerumbone onto dorsal skin of hairless mice induces activation of NF-E2-related factor 2 (Nrf2) and expression of heme oxygenase-1 (HO-1). We compared the levels of HO-1 protein in the skin of zerumbone-treated Nrf2 wild-type and Nrf2 knockout mice, and nrf2-deficient mice expressed HO-1 protein to a much lesser extent than the wild-type animals following topical application of zerumbone. Treatment of mouse epidermal JB6 cells with zerumbone caused a marked increase of Nrf2 nuclear translocation followed by the promoter activity of HO-1, and also enhanced direct binding of Nrf2 to the antioxidant response element. Moreover, knockdown of Nrf2 in JB6 cells diminished the zerumbone-induced upregulation of HO-1. Notably, α-humulene and 8-hydroxy-α-humulene, the structural analogues of zerumbone that lack the α,β-unsaturated carbonyl group, failed to activate Nrf2 and were unable to increase HO-1 expression. Unlike zerumbone, these nonelectrophilic analogues could not suppress the 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced JB6 cell transformation and the intracellular accumulation of reactive oxygen species (ROS). Interestingly, when JB6 cells were treated with carbon monoxide-releasing molecule that mimics the HO-1 activity, the TPA-induced ROS production was markedly reduced. Taken together, these findings suggest that upregulation of HO-1 expression by zerumbone is mediated through activation of Nrf2 signaling, which provides a mechanistic basis for the chemopreventive effects of this sesquiterpene on mouse skin carcinogenesis.
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Affiliation(s)
- Jun-Wan Shin
- College of Pharmacy, Graduate School of Convergence Science and Technology, Seoul National University, South Korea
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241
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Nagi MN, Almakki HA. Thymoquinone supplementation induces quinone reductase and glutathione transferase in mice liver: possible role in protection against chemical carcinogenesis and toxicity. Phytother Res 2011; 23:1295-8. [PMID: 19277968 DOI: 10.1002/ptr.2766] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Thymoquinone (TQ), the main constituents of the volatile oil from Nigella sativa seeds is reported to protect laboratory animals against chemical carcinogenesis and toxicity through mechanism(s) that is not fully understood. Among possible mechanism(s), protection could be mediated via induction of detoxifying enzymes, including quinone reductase and glutathione transferase. This study was undertaken to investigate whether oral administration of TQ increases the activities of quinone reductase and glutathione transferase in mice liver. Overdose of TQ, when administered intraperitoneally, caused a marked depletion of hepatic glutathione in both a time- and dose- dependent manner, a characteristic of a group of compounds known as Michael reaction acceptors which are known to act as inducers of enzymes that protect against chemical carcinogenesis and toxicity. TQ was given (1, 2 and 4 mg/kg/day p.o.) for five days to test the chemical inducibility of quinone reductase and glutathione transferase in mice liver. TQ administration produced significant increase in the activities of quinone reductase (147, 196 and 197% of control, respectively) and glutathione transferase (125, 152 and 154% of control, respectively). In conclusion, oral administration of TQ is effective in increasing the activities of quinone reductase and glutathione transferase and makes TQ a promising prophylactic agent against chemical carcinogenesis and toxicity.
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Affiliation(s)
- Mahmoud N Nagi
- Department of Pharmacology, College of Pharmacy, King Saud University, P.O. Box 2457, Riyadh 11451, Kingdom of Saudi Arabia.
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242
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Singh S, Vrishni S, Singh BK, Rahman I, Kakkar P. Nrf2-ARE stress response mechanism: a control point in oxidative stress-mediated dysfunctions and chronic inflammatory diseases. Free Radic Res 2011; 44:1267-88. [PMID: 20815789 DOI: 10.3109/10715762.2010.507670] [Citation(s) in RCA: 219] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Nrf2, a redox sensitive transcription factor, plays a pivotal role in redox homeostasis during oxidative stress. Nrf2 is sequestered in cytosol by an inhibitory protein Keap1 which causes its proteasomal degradation. In response to electrophilic and oxidative stress, Nrf2 is activated, translocates to nucleus, binds to antioxidant response element (ARE), thus upregulates a battery of antioxidant and detoxifying genes. This function of Nrf2 can be significant in the treatment of diseases, such as cancer, neurodegenerative, cardiovascular and pulmonary complications, where oxidative stress causes Nrf2 derangement. Nrf2 upregulating potential of phytochemicals has been explored, in facilitating cure for various ailments while, in cancer cells, Nrf2 upregulation causes chemoresistance. Therefore, Nrf2 emerges as a key regulator in oxidative stress-mediated diseases and Nrf2 silencing can open avenues in cancer treatment. This review summarizes Nrf2-ARE stress response mechanism and its role as a control point in oxidative stress-induced cellular dysfunctions including chronic inflammatory diseases.
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Affiliation(s)
- Shruti Singh
- Herbal Research Section, Indian Institute of Toxicology Research, CSIR, PO Box-80, Mahatma Gandhi Marg, Lucknow 226001, Uttar Pradesh, India
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243
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Mulliner D, Wondrousch D, Schüürmann G. Predicting Michael-acceptor reactivity and toxicity through quantum chemical transition-state calculations. Org Biomol Chem 2011; 9:8400-12. [DOI: 10.1039/c1ob06065a] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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244
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Preliminary evaluation of two radioiodinated maleimide derivatives targeting peripheral and membrane sulfhydryl groups for in vitro cell labeling. Appl Radiat Isot 2011; 69:163-70. [DOI: 10.1016/j.apradiso.2010.08.010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2010] [Revised: 07/14/2010] [Accepted: 08/11/2010] [Indexed: 11/20/2022]
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245
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Park SJ, Kang SH, Kang YK, Eom YB, Koh KO, Kim DY, Youn HS. Inhibition of homodimerization of Toll-like receptor 4 by 4-oxo-4-(2-oxo-oxazolidin-3-yl)-but-2-enoic acid ethyl ester. Int Immunopharmacol 2011; 11:19-22. [DOI: 10.1016/j.intimp.2010.09.020] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2010] [Revised: 09/17/2010] [Accepted: 09/27/2010] [Indexed: 01/23/2023]
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246
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Giudice A, Arra C, Turco MC. Review of molecular mechanisms involved in the activation of the Nrf2-ARE signaling pathway by chemopreventive agents. Methods Mol Biol 2010; 647:37-74. [PMID: 20694660 DOI: 10.1007/978-1-60761-738-9_3] [Citation(s) in RCA: 180] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Human exposures to environmental toxicants have been associated with etiology of many diseases including inflammation, cancer, and cardiovascular and neurodegenerative disorders. To counteract the detrimental effect of environmental insults, mammalian cells have evolved a hierarchy of sophisticated sensing and signaling mechanisms to turn on or off endogenous antioxidant responses accordingly. One of the major cellular antioxidant responses is the induction of antioxidative and carcinogen-detoxification enzymes through the cytoplasmic oxidative stress system (Nrf2-Keap1) activated by a variety of natural and synthetic chemopreventive agents. Under normal conditions, Keap1 anchors the Nrf2 transcription factor within the cytoplasm targeting it for ubiquitination and proteasomal degradation to maintain low levels of Nrf2 that mediate the constitutive expression of Nrf2 downstream genes. When cells are exposed to chemopreventive agents and oxidative stress, a signal involving phosphorylation and/or redox modification of critical cysteine residues in Keap1 inhibits the enzymatic activity of the Keap1-Cul3-Rbx1 E3 ubiquitin ligase complex, resulting in decreased Nrf2 ubiquitination and degradation. As a consequence, free Nrf2 translocates into the nucleus and in combination with other transcription factors (e.g., sMaf, ATF4, JunD, PMF-1) transactivates the antioxidant response elements (AREs)/electrophile response elements (EpREs) of many cytoprotective genes, as well as Nrf2 itself. Upon recovery of cellular redox homeostasis, Keap1 travels into the nucleus to dissociate Nrf2 from the ARE. Subsequently, the Nrf2-Keap1 complex is exported out of the nucleus by the nuclear export sequence (NES) in Keap1. Once in the cytoplasm, the Nrf2-Keap1 complex associates with the Cul3-Rbx1 core ubiquitin machinery, resulting in degradation of Nrf2 and termination of the Nrf2/ARE signaling pathway. The discovery of multiple nuclear localization signals (NLSs) and nuclear export signals (NESs) in Nrf2 also suggests that the nucleocytoplasm translocation of transcription factors is the consequence of a dynamic equilibrium of multivalent NLSs and NESs. On the other hand, Keap1 may provide an additional regulation of the quantity of Nrf2 both in basal and inducible conditions. This chapter summarizes the current body of knowledge regarding the molecular mechanisms through which ARE inducers (chemopreventive agents) regulate the coordinated transcriptional induction of genes encoding phase II and antioxidant enzymes as well as other defensive proteins, via the nuclear factor-erythroid 2 (NF-E2-p45)-related factor 2(Nrf2)/(ARE) signaling pathway.
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Affiliation(s)
- Aldo Giudice
- G. Pascale Foundation National Cancer Institute, Naples, Italy.
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247
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Shanmugam V, Ronen M, Shalaby S, Larkov O, Rachamim Y, Hadar R, Rose MS, Carmeli S, Horwitz BA, Lev S. The fungal pathogen Cochliobolus heterostrophus responds to maize phenolics: novel small molecule signals in a plant-fungal interaction. Cell Microbiol 2010; 12:1421-34. [PMID: 20438575 DOI: 10.1111/j.1462-5822.2010.01479.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The transcription factor ChAP1 of the fungal pathogen of maize, Cochliobolus heterostrophus, responds to oxidative stress by migration to the nucleus and activation of antioxidant genes. Phenolic and related compounds found naturally in the host also trigger nuclear localization of ChAP1, but only slight upregulation of some antioxidant genes. ChAP1 thus senses phenolic compounds without triggering a strong antioxidant response. We therefore searched for genes whose expression is regulated by phenolic compounds and/or ChAP1. The C. heterostrophus genome contains a cluster of genes for metabolism of phenolics. One such gene, catechol dioxygenase CCHD1, was induced at least 10-fold by caffeic and coumaric acids. At high phenolic concentrations (≥ 1.6 mM), ChAP1 is needed for maximum CCHD1 expression. At micromolar levels of phenolics CCHD1 is as strongly induced in chap1 mutants as in the wild type. The pathogen thus detects phenolics by at least two signalling pathways: one causing nuclear retention of ChAP1, and another triggering induction of CCHD1 expression. The low concentrations required for induction of CCHD1 indicate fungal receptors for plant phenolics. Symbiotic and pathogenic bacteria are known to detect phenolics, and our findings generalize this to a eukaryotic pathogen. Phenolics and related compounds thus provide a ubiquitous plant-derived signal.
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Affiliation(s)
- Veerubommu Shanmugam
- Department of Biology, Technion-Israel Institute of Technology, Haifa 32000, Israel
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248
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LoPachin RM, Gavin T, Geohagen BC, Zhang L, Casper D, Lekhraj R, Barber DS. β-dicarbonyl enolates: a new class of neuroprotectants. J Neurochem 2010; 116:132-43. [PMID: 21054388 DOI: 10.1111/j.1471-4159.2010.07091.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Curcumin, phloretin and structurally related phytopolyphenols have well-described neuroprotective properties that appear to be at least partially mediated by 1,3-dicarbonyl enol substructures that form nucleophilic enolates. Based on their structural similarities, we tested the hypothesis that enolates of simple 1,3-dicarbonyl compounds such as acetylacetone might also possess neuroprotective actions. Our results show that the β-diketones, particularly 2-acetylcyclopentanone, protected rat striatal synaptosomes and a neuronal cell line from thiol loss and toxicity induced by acrolein, an electrophilic α,β-unsaturated aldehyde. The 1,3-dicarbonyl compounds also provided substantial cytoprotection against toxicity induced by hydrogen peroxide in a cellular model of oxidative stress. Initial chemical characterization in cell-free systems indicated that the 1,3-dicarbonyl compounds acted as surrogate nucleophilic targets that slowed the rate of sulfhydryl loss caused by acrolein. Although the selected 1,3-dicarbonyl congeners did not scavenge free radicals, metal ion chelation was a significant property of both acetylacetone and 2-acetylcyclopentanone. Our data suggest that the 1,3-dicarbonyl enols represent a new class of neuroprotectants that scavenge electrophilic metal ions and unsaturated aldehydes through their nucleophilic enolate forms. As such, these enols might be rational candidates for treatment of acute or chronic neurodegenerative conditions that have oxidative stress as a common molecular etiology.
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Affiliation(s)
- Richard M LoPachin
- Department of Anesthesiology, Albert Einstein College of Medicine, Montefiore Medical Center, Bronx, New York, 10467-2409 USA.
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249
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Calabrese V, Cornelius C, Dinkova-Kostova AT, Calabrese EJ, Mattson MP. Cellular stress responses, the hormesis paradigm, and vitagenes: novel targets for therapeutic intervention in neurodegenerative disorders. Antioxid Redox Signal 2010; 13:1763-811. [PMID: 20446769 PMCID: PMC2966482 DOI: 10.1089/ars.2009.3074] [Citation(s) in RCA: 570] [Impact Index Per Article: 40.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/23/2009] [Revised: 04/27/2010] [Accepted: 05/01/2010] [Indexed: 12/22/2022]
Abstract
Despite the capacity of chaperones and other homeostatic components to restore folding equilibrium, cells appear poorly adapted for chronic oxidative stress that increases in cancer and in metabolic and neurodegenerative diseases. Modulation of endogenous cellular defense mechanisms represents an innovative approach to therapeutic intervention in diseases causing chronic tissue damage, such as in neurodegeneration. This article introduces the concept of hormesis and its applications to the field of neuroprotection. It is argued that the hormetic dose response provides the central underpinning of neuroprotective responses, providing a framework for explaining the common quantitative features of their dose-response relationships, their mechanistic foundations, and their relationship to the concept of biological plasticity, as well as providing a key insight for improving the accuracy of the therapeutic dose of pharmaceutical agents within the highly heterogeneous human population. This article describes in mechanistic detail how hormetic dose responses are mediated for endogenous cellular defense pathways, including sirtuin and Nrf2 and related pathways that integrate adaptive stress responses in the prevention of neurodegenerative diseases. Particular attention is given to the emerging role of nitric oxide, carbon monoxide, and hydrogen sulfide gases in hormetic-based neuroprotection and their relationship to membrane radical dynamics and mitochondrial redox signaling.
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250
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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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