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Pharmacological Modulations of Nrf2 and Therapeutic Implications in Aneurysmal Subarachnoid Hemorrhage. Molecules 2023; 28:molecules28041747. [PMID: 36838735 PMCID: PMC9963186 DOI: 10.3390/molecules28041747] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2022] [Revised: 02/07/2023] [Accepted: 02/08/2023] [Indexed: 02/15/2023] Open
Abstract
An aneurysmal subarachnoid hemorrhage (aSAH) is a subtype of stroke with high morbidity and mortality. The main causes of a poor prognosis include early brain injury (EBI) and delayed vasospasm, both of which play a significant role in the pathophysiological process. As an important mechanism of EBI and delayed vasospasm, oxidative stress plays an important role in the pathogenesis of aSAH by producing reactive oxygen species (ROS) through the mitochondria, hemoglobin, or enzymatic pathways in the early stages of aSAH. As a result, antioxidant therapy, which primarily targets the Nrf2-related pathway, can be employed as a potential strategy for treating aSAH. In the early stages of aSAH development, increasing the expression of antioxidant enzymes and detoxifying enzymes can relieve oxidative stress, reduce brain damage, and improve prognosis. Herein, the regulatory mechanisms of Nrf2 and related pharmacological compounds are reviewed, and Nrf2-targeted drugs are proposed as potential treatments for aSAH.
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Underlying Anticancer Mechanisms and Synergistic Combinations of Phytochemicals with Cancer Chemotherapeutics: Potential Benefits and Risks. J FOOD QUALITY 2022. [DOI: 10.1155/2022/1189034] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Cancer therapies are associated with various challenges including the emergence of multidrug resistant tumors, toxicological issues, severe side effects, and economic burden. To counteract these effects, natural products as substitutes and adjuvant therapies have received considerable attention owing to their safety, efficacy, and economic aspects. Various preclinical and clinical studies revealed that natural products and their combinations with chemotherapeutics mediate their anticancer effects via modulation of various signaling pathways implicated in promoting apoptosis, inhibiting excessive cellular proliferation, and mobilizing the immune system. Several lead phytochemicals including curcumin, resveratrol, quercetin, and cannabinoids synergistically act with cancer chemotherapeutics reducing cell proliferation and inducing apoptosis and cell cycle arrest. However, clinical studies on the subject matter are limited and need further extensive studies. It has been observed that patients undergoing chemotherapy use alternative therapies to ameliorate the symptoms associated with the use of chemotherapeutic agents. Nevertheless, some of the patients inform their physicians regarding herbal medicine during chemotherapy while others do not, and even most of the patients do not know the composition of herbal medicine they consume during chemotherapy. Herbal interactions with chemotherapeutics are associated with both beneficial and harmful aspects, but the beneficial aspect overweighs the harmful ones in terms of controlling the symptoms associated with the chemotherapy. Nonetheless, a large number of herbal medicines have been demonstrated to have synergistic effect with chemotherapy and alleviate the side effects of chemotherapeutic agents. The concomitant use of the majority of herbal medicines with chemotherapy has been demonstrated to be beneficial in multiple malignant tumors like cancer of blood, lungs, kidneys, liver, skin, and gastrointestinal tract. However, herbal medicines which possess positive interaction and improve the quality of life of patients should be sorted out and integrated with the chemotherapy. There should be a quality control system for the appraisal of herbal medicine, and there should also be an appropriate system of patient-doctor communication to counsel the patients regarding the beneficial and deleterious effects of the herbal medicine in combination with chemotherapy.
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Kumar H, Kumar RM, Bhattacharjee D, Somanna P, Jain V. Role of Nrf2 Signaling Cascade in Breast Cancer: Strategies and Treatment. Front Pharmacol 2022; 13:720076. [PMID: 35571115 PMCID: PMC9098811 DOI: 10.3389/fphar.2022.720076] [Citation(s) in RCA: 25] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2021] [Accepted: 03/31/2022] [Indexed: 12/30/2022] Open
Abstract
Breast cancer is the second leading cancer among all types of cancers. It accounts for 12% of the total cases of cancers. The complex and heterogeneous nature of breast cancer makes it difficult to treat in advanced stages. The expression of various enzymes and proteins is regulated by several molecular pathways. Oxidative stress plays a vital role in cellular events that are generally regulated by nuclear factor erythroid 2-related factor 2 (Nrf2). The exact mechanism of Nrf2 behind cytoprotective and antioxidative properties is still under investigation. In healthy cells, Nrf2 expression is lower, which maintains antioxidative stress; however, cancerous cells overexpress Nrf2, which is associated with various phenomena, such as the development of drug resistance, angiogenesis, development of cancer stem cells, and metastasis. Aberrant Nrf2 expression diminishes the toxicity and potency of therapeutic anticancer drugs and provides cytoprotection to cancerous cells. In this article, we have discussed the attributes associated with Nrf2 in the development of drug resistance, angiogenesis, cancer stem cell generation, and metastasis in the specific context of breast cancer. We also discussed the therapeutic strategies employed against breast cancer exploiting Nrf2 signaling cascades.
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Affiliation(s)
| | | | | | | | - Vikas Jain
- Department of Pharmaceutics, JSS College of Pharmacy, JSS Academy of Higher Education and Research, Mysuru, India
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Scuto M, Ontario ML, Salinaro AT, Caligiuri I, Rampulla F, Zimbone V, Modafferi S, Rizzolio F, Canzonieri V, Calabrese EJ, Calabrese V. Redox modulation by plant polyphenols targeting vitagenes for chemoprevention and therapy: Relevance to novel anti-cancer interventions and mini-brain organoid technology. Free Radic Biol Med 2022; 179:59-75. [PMID: 34929315 DOI: 10.1016/j.freeradbiomed.2021.12.267] [Citation(s) in RCA: 27] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/14/2021] [Revised: 12/07/2021] [Accepted: 12/16/2021] [Indexed: 12/26/2022]
Abstract
The scientific community, recently, has focused notable attention on the chemopreventive and therapeutic effects of dietary polyphenols for human health. Emerging evidence demonstrates that polyphenols, flavonoids and vitamins counteract and neutralize genetic and environmental stressors, particularly oxidative stress and inflammatory process closely connected to cancer initiation, promotion and progression. Interestingly, polyphenols can exert antioxidant or pro-oxidant cytotoxic effects depending on their endogenous concentration. Notably, polyphenols at high dose act as pro-oxidants in a wide type of cancer cells by inhibiting Nrf2 pathway and the expression of antioxidant vitagenes, such as NAD(P)H-quinone oxidoreductase (NQO1), glutathione transferase (GT), GPx, heme oxygenase-1 (HO-1), sirtuin-1 (Sirt1) and thioredoxin (Trx) system which play an essential role in the metabolism of reactive oxygen species (ROS), detoxification of xenobiotics and inhibition of cancer progression, by inducing apoptosis and cell cycle arrest according to the hormesis approach. Importantly, mutagenesis of Nrf2 pathway can exacerbate its "dark side" role, representing a crucial event in the initiation stage of carcinogenesis. Herein, we review the hormetic effects of polyphenols and nanoincapsulated-polyphenols in chemoprevention and treatment of brain tumors via activation or inhibition of Nrf2/vitagenes to suppress carcinogenesis in the early stages, and thus inhibit its progression. Lastly, we discuss innovative preclinical approaches through mini-brain tumor organoids to study human carcinogenesis, from basic cancer research to clinical practice, as promising tools to recapitulate the arrangement of structural neuronal tissues and biological functions of the human brain, as well as test drug toxicity and drive personalized and precision medicine in brain cancer.
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Affiliation(s)
- Maria Scuto
- Department of Biomedical and Biotechnological Sciences, University of Catania, 95124, Catania, Italy; Pathology Unit, Centro di Riferimento Oncologico di Aviano (CRO) IRCCS, 33081, Aviano, Italy
| | - Maria Laura Ontario
- Department of Biomedical and Biotechnological Sciences, University of Catania, 95124, Catania, Italy
| | - Angela Trovato Salinaro
- Department of Biomedical and Biotechnological Sciences, University of Catania, 95124, Catania, Italy.
| | - Isabella Caligiuri
- Pathology Unit, Centro di Riferimento Oncologico di Aviano (CRO) IRCCS, 33081, Aviano, Italy
| | - Francesco Rampulla
- Department of Biomedical and Biotechnological Sciences, University of Catania, 95124, Catania, Italy
| | - Vincenzo Zimbone
- Department of Biomedical and Biotechnological Sciences, University of Catania, 95124, Catania, Italy
| | - Sergio Modafferi
- Department of Biomedical and Biotechnological Sciences, University of Catania, 95124, Catania, Italy
| | - Flavio Rizzolio
- Pathology Unit, Centro di Riferimento Oncologico di Aviano (CRO) IRCCS, 33081, Aviano, Italy; Department of Molecular Sciences and Nanosystems, Ca'Foscari University of Venice, 30123, Venezia, Italy
| | - Vincenzo Canzonieri
- Pathology Unit, Centro di Riferimento Oncologico di Aviano (CRO) IRCCS, 33081, Aviano, Italy; Department of Medical, Surgical and Health Sciences, University of Trieste, 34127, Trieste, Italy
| | - Edward J Calabrese
- Department of Environmental Health Sciences, Morrill I, N344, University of Massachusetts, Amherst, MA, 01003, USA
| | - Vittorio Calabrese
- Department of Biomedical and Biotechnological Sciences, University of Catania, 95124, Catania, Italy.
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Visioli F, Ingram A, Beckman JS, Magnusson KR, Hagen TM. Strategies to protect against age-related mitochondrial decay: Do natural products and their derivatives help? Free Radic Biol Med 2022; 178:330-346. [PMID: 34890770 DOI: 10.1016/j.freeradbiomed.2021.12.008] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 11/24/2021] [Accepted: 12/04/2021] [Indexed: 12/12/2022]
Abstract
Mitochondria serve vital roles critical for overall cellular function outside of energy transduction. Thus, mitochondrial decay is postulated to be a key factor in aging and in age-related diseases. Mitochondria may be targets of their own decay through oxidative damage. However, treating animals with antioxidants has been met with only limited success in rejuvenating mitochondrial function or in increasing lifespan. A host of nutritional strategies outside of using traditional antioxidants have been devised to promote mitochondrial function. Dietary compounds are under study that induce gene expression, enhance mitochondrial biogenesis, mitophagy, or replenish key metabolites that decline with age. Moreover, redox-active compounds may now be targeted to mitochondria which improve their effectiveness. Herein we review the evidence that representative dietary effectors modulate mitochondrial function by stimulating their renewal or reversing the age-related loss of key metabolites. While in vitro evidence continues to accumulate that many of these compounds benefit mitochondrial function and/or prevent their decay, the results using animal models and, in some instances human clinical trials, are more mixed and sometimes even contraindicated. Thus, further research on optimal dosage and age of intervention are warranted before recommending potential mitochondrial rejuvenating compounds for human use.
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Affiliation(s)
- Francesco Visioli
- Department of Molecular Medicine, University of Padova, Italy; IMDEA-Food, Madrid, Spain
| | - Avery Ingram
- Linus Pauling Institute, Oregon State University, Corvallis, OR, 97331, USA; Department of Biochemistry and Biophysics, Oregon State University, Corvallis, OR, 97331, USA
| | - Joseph S Beckman
- Linus Pauling Institute, Oregon State University, Corvallis, OR, 97331, USA; Department of Biochemistry and Biophysics, Oregon State University, Corvallis, OR, 97331, USA
| | - Kathy R Magnusson
- Linus Pauling Institute, Oregon State University, Corvallis, OR, 97331, USA
| | - Tory M Hagen
- Linus Pauling Institute, Oregon State University, Corvallis, OR, 97331, USA; Department of Biochemistry and Biophysics, Oregon State University, Corvallis, OR, 97331, USA.
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Saggam A, Tillu G, Dixit S, Chavan-Gautam P, Borse S, Joshi K, Patwardhan B. Withania somnifera (L.) Dunal: A potential therapeutic adjuvant in cancer. JOURNAL OF ETHNOPHARMACOLOGY 2020; 255:112759. [PMID: 32173425 DOI: 10.1016/j.jep.2020.112759] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Revised: 02/05/2020] [Accepted: 03/08/2020] [Indexed: 05/27/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Withania somnifera (L.) Dunal (WS) is one of the moststudied Rasayana botanicals used in Ayurveda practice for its immunomodulatory, anti-aging, adaptogenic, and rejuvenating effects. The botanical is being used for various clinical indications, including cancer. Several studies exploring molecular mechanisms of WS suggest its possible role in improving clinical outcomes in cancer management. Therefore, research on WS may offer new insights in rational development of therapeutic adjuvants for cancer. AIM OF THIS REVIEW The review aims at providing a detailed analysis of in silico, in vitro, in vivo, and clinical studies related to WS and cancer. It suggests possible role of WS in regulating molecular mechanisms associated with carcinogenesis. The review discusses potential of WS in cancer management in terms of cancer prevention, anti-cancer activity, and enhancing efficacy of cancer therapeutics. MATERIAL AND METHODS The present narrative review offers a critical analysis of published literature on WS studies in cancer. The reported studies were analysed in the context of pathophysiology of cancer, commonly referred as 'cancer hallmarks'. The review attempts to bridge Ayurveda knowledge with biological insights into molecular mechanisms of cancer. RESULTS Critical analysisof the published literature suggests an anti-cancer potential of WS with a key role in cancer prevention. The possible mechanisms for these effects are associated with the modulation of apoptotic, proliferative, and metastatic markers in cancer. WS can attenuate inflammatory responses and enzymes involved in invasion and metastatic progression of cancer.The properties of WS are likely to be mediated through withanolides, which may activate tumor suppressor proteins to restrict proliferation of cancer cells. Withanolides also regulate the genomic instability, and energy metabolism of cancer cells. The reported studies indicate the need for deeper understanding of molecular mechanisms of WS in inhibiting angiogenesis and promoting immunosurveillance. Additionally, WS can augment efficacy and safety of cancer therapeutics. CONCLUSION The experimentally-supported evidence of immunomodulatory, anti-cancer, adaptogenic, and regenerative attributes of WS suggest its therapeutic adjuvant potential in cancer management. The adjuvant properties of withanolides can modulate multidrug resistance and reverse chemotherapy-induced myelosuppression. These mechanisms need to be further explored in systematically designed translational and clinical studies that will pave the way for integration of WS as a therapeutic adjuvant in cancer management.
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Affiliation(s)
- Akash Saggam
- AYUSH Center of Excellence, Center for Complementary and Integrative Health, Interdisciplinary School of Health Sciences, Savitribai Phule Pune University, Pune, India
| | - Girish Tillu
- AYUSH Center of Excellence, Center for Complementary and Integrative Health, Interdisciplinary School of Health Sciences, Savitribai Phule Pune University, Pune, India
| | | | - Preeti Chavan-Gautam
- AYUSH Center of Excellence, Center for Complementary and Integrative Health, Interdisciplinary School of Health Sciences, Savitribai Phule Pune University, Pune, India
| | - Swapnil Borse
- AYUSH Center of Excellence, Center for Complementary and Integrative Health, Interdisciplinary School of Health Sciences, Savitribai Phule Pune University, Pune, India
| | - Kalpana Joshi
- Department of Biotechnology, Sinhgad College of Engineering, Pune, India
| | - Bhushan Patwardhan
- AYUSH Center of Excellence, Center for Complementary and Integrative Health, Interdisciplinary School of Health Sciences, Savitribai Phule Pune University, Pune, India.
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Potential Applications of NRF2 Modulators in Cancer Therapy. Antioxidants (Basel) 2020; 9:antiox9030193. [PMID: 32106613 PMCID: PMC7139512 DOI: 10.3390/antiox9030193] [Citation(s) in RCA: 89] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Revised: 02/21/2020] [Accepted: 02/21/2020] [Indexed: 01/17/2023] Open
Abstract
The nuclear factor erythroid 2-related factor 2 (NRF2)-Kelch-like ECH-associated protein 1 (KEAP1) regulatory pathway plays an essential role in protecting cells and tissues from oxidative, electrophilic, and xenobiotic stress. By controlling the transactivation of over 500 cytoprotective genes, the NRF2 transcription factor has been implicated in the physiopathology of several human diseases, including cancer. In this respect, accumulating evidence indicates that NRF2 can act as a double-edged sword, being able to mediate tumor suppressive or pro-oncogenic functions, depending on the specific biological context of its activation. Thus, a better understanding of the mechanisms that control NRF2 functions and the most appropriate context of its activation is a prerequisite for the development of effective therapeutic strategies based on NRF2 modulation. In line of principle, the controlled activation of NRF2 might reduce the risk of cancer initiation and development in normal cells by scavenging reactive-oxygen species (ROS) and by preventing genomic instability through decreased DNA damage. In contrast however, already transformed cells with constitutive or prolonged activation of NRF2 signaling might represent a major clinical hurdle and exhibit an aggressive phenotype characterized by therapy resistance and unfavorable prognosis, requiring the use of NRF2 inhibitors. In this review, we will focus on the dual roles of the NRF2-KEAP1 pathway in cancer promotion and inhibition, describing the mechanisms of its activation and potential therapeutic strategies based on the use of context-specific modulation of NRF2.
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Pompili S, Sferra R, Gaudio E, Viscido A, Frieri G, Vetuschi A, Latella G. Can Nrf2 Modulate the Development of Intestinal Fibrosis and Cancer in Inflammatory Bowel Disease? Int J Mol Sci 2019; 20:E4061. [PMID: 31434263 PMCID: PMC6720292 DOI: 10.3390/ijms20164061] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Revised: 08/08/2019] [Accepted: 08/12/2019] [Indexed: 12/15/2022] Open
Abstract
One of the main mechanisms carried out by the cells to counteract several forms of stress is the activation of the nuclear factor erythroid 2-related factor (Nrf2) signaling. Nrf2 signaling controls the expression of many genes through the binding of a specific cis-acting element known as the antioxidant response element (ARE). Activation of Nrf2/ARE signaling can mitigate several pathologic mechanisms associated with an autoimmune response, digestive and metabolic disorders, as well as respiratory, cardiovascular, and neurodegenerative diseases. Indeed, several studies have demonstrated that Nrf2 pathway plays a key role in inflammation and in cancer development in many organs, including the intestine. Nrf2 appears to be involved in inflammatory bowel disease (IBD), an immune-mediated chronic and disabling disease, with a high risk of developing intestinal fibrotic strictures and cancer. Currently, drugs able to increase cytoprotective Nrf2 function are in clinical trials or already being used in clinical practice to reduce the progression of some degenerative conditions. The role of Nrf2 in cancer development and progression is controversial, and drugs able to inhibit abnormal levels of Nrf2 are also under investigation. The goal of this review is to analyze and discuss Nrf2-dependent signals in the initiation and progression of intestinal fibrosis and cancers occurring in IBD.
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Affiliation(s)
- Simona Pompili
- Department of Biotechnological and Applied Clinical Sciences, University of L'Aquila, 67100 L'Aquila, Italy
| | - Roberta Sferra
- Department of Biotechnological and Applied Clinical Sciences, University of L'Aquila, 67100 L'Aquila, Italy
| | - Eugenio Gaudio
- Department of Anatomical, Histological, Forensic Medicine and Orthopedic Sciences, Sapienza University of Rome, 00185 Rome, Italy
| | - Angelo Viscido
- Department of Life, Health and Environmental Sciences, Gastroenterology, Hepatology and Nutrition Division, University of L'Aquila, 67100 L'Aquila, Italy
| | - Giuseppe Frieri
- Department of Life, Health and Environmental Sciences, Gastroenterology, Hepatology and Nutrition Division, University of L'Aquila, 67100 L'Aquila, Italy
| | - Antonella Vetuschi
- Department of Biotechnological and Applied Clinical Sciences, University of L'Aquila, 67100 L'Aquila, Italy
| | - Giovanni Latella
- Department of Life, Health and Environmental Sciences, Gastroenterology, Hepatology and Nutrition Division, University of L'Aquila, 67100 L'Aquila, Italy.
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Sadeghi MR, Jeddi F, Soozangar N, Somi MH, Samadi N. The role of Nrf2-Keap1 axis in colorectal cancer, progression, and chemoresistance. Tumour Biol 2017. [PMID: 28621229 DOI: 10.1177/1010428317705510] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Colorectal cancer is the third common cancer after lung and genital cancers worldwide with more than 1.2 million new cases diagnosed annually. Although extensive progress has been made in the treatment of colorectal cancer, finding novel targets for early diagnosis and effective treatment of these patients is an urgent need. Nuclear factor-erythroid 2-kelch-like ECH-associated protein 1 signaling pathway plays a key role in protecting cells from the damage of intracellular oxidative stress and extracellular oxidizing agents. Nuclear factor-erythroid 2 is a transcription factor that creates intracellular redox homeostasis via transcriptional activity and interaction with kelch-like ECH-associated protein 1. Furthermore, it contributes to survival and chemoresistance of colorectal cancer cells which is mediated by overexpression of cytoprotective and multidrug resistance genes. In this review, the dual role of nuclear factor-erythroid 2 signaling in induction of colorectal cancer cell survival and death as well as the possibility of targeting nuclear factor-erythroid 2-kelch-like ECH-associated protein 1 axis as an advanced strategy in prevention and effective treatment of colorectal cancer patients have been discussed.
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Affiliation(s)
- Mohammad Reza Sadeghi
- 1 Liver and Gastrointestinal Diseases Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
- 2 Department of Molecular Medicine, Faculty of Advanced Medical Sciences, Tabriz University of Medical Sciences, Tabriz, Iran
- 3 Student Research Committee, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Farhad Jeddi
- 1 Liver and Gastrointestinal Diseases Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
- 2 Department of Molecular Medicine, Faculty of Advanced Medical Sciences, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Narges Soozangar
- 1 Liver and Gastrointestinal Diseases Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
- 2 Department of Molecular Medicine, Faculty of Advanced Medical Sciences, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Mohammad Hossein Somi
- 1 Liver and Gastrointestinal Diseases Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Nasser Samadi
- 1 Liver and Gastrointestinal Diseases Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
- 2 Department of Molecular Medicine, Faculty of Advanced Medical Sciences, Tabriz University of Medical Sciences, Tabriz, Iran
- 4 Department of Biochemistry and Clinical Laboratories, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran
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Block KI, Gyllenhaal C. Clinical Corner: Herb-Drug Interactions in Cancer Chemotherapy: Theoretical Concerns Regarding Drug Metabolizing Enzymes. Integr Cancer Ther 2016; 1:83-9. [PMID: 14664751 DOI: 10.1177/153473540200100118] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Interactions between herbal medicines and conventional drugs have recently been reported; the most significant herb with such drug interactions is Saint John's wort, an inducer of cytochrome P450 3A3/4, an enzyme responsible for clearance of many clinically important drugs from the body. Foods (especially grapefruit) and habits or lifestyle factors such as smoking or alcohol consumption may also alter the metabolism of drugs through effects on the cytochrome P450 system. The authors review here the functioning of the drug-metabolizing enzymes and discuss their particular sig nificance in cancer chemotherapy treatment. They then present the herbal medicines, foods, and lifestyle factors that induce or inhibit drug-metabolizing enzymes that are important for both cancer chemotherapy drugs and drugs used adjunctively in cancer treatment. It is notable that no actual herb-drug interactions have been reported clinically in cancer treatment, and their potential for interaction still must be regarded as theoretical. Although some chemotherapy patients may be interested in taking herbal medicines that could potentially interact with cancer chemotherapy agents, it may be wise to counsel them to use other means of addressing the problems for which they use specific herbs during the time they receive chemotherapy.
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Affiliation(s)
- Keith I Block
- Block Center for Integrative Cancer Care, 1800 Sherman, Suite 515, Evanston, IL 60201, USA.
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3H-1,2-dithiole-3-thione protects retinal pigment epithelium cells against Ultra-violet radiation via activation of Akt-mTORC1-dependent Nrf2-HO-1 signaling. Sci Rep 2016; 6:25525. [PMID: 27151674 PMCID: PMC4858705 DOI: 10.1038/srep25525] [Citation(s) in RCA: 69] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2015] [Accepted: 04/14/2016] [Indexed: 12/14/2022] Open
Abstract
Excessive UV radiation and reactive oxygen species (ROS) cause retinal pigment epithelium (RPE) cell injuries. Nrf2 regulates transcriptional activation of many anti-oxidant genes. Here, we tested the potential role of 3H-1,2-dithiole-3-thione (D3T) against UV or ROS damages in cultured RPE cells (both primary cells and ARPE-19 line). We showed that D3T significantly inhibited UV-/H2O2-induced RPE cell death and apoptosis. UV-stimulated ROS production was dramatically inhibited by D3T pretreatment. D3T induced Nrf2 phosphorylation in cultured RPE cells, causing Nrf2 disassociation with KEAP1 and its subsequent nuclear accumulation. This led to expression of antioxidant response elements (ARE)-dependent gene heme oxygenase-1 (HO-1). Nrf2-HO-1 activation was required for D3T-mediated cytoprotective effect. Nrf2 shRNA knockdown or S40T dominant negative mutation as well as the HO-1 inhibitor Zinc protoporphyrin (ZnPP) largely inhibited D3T’s RPE cytoprotective effects against UV radiation. Yet, exogenous overexpression Nrf2 enhanced D3T’s activity in RPE cells. Further studies showed that D3T activated Akt/mTORC1 in cultured RPE cells. Akt-mTORC1 inhibitors, or Akt1 knockdown by shRNA, not only inhibited D3T-induced Nrf2-HO-1 activation, but also abolished the RPE cytoprotective effects. In vivo, D3T intravitreal injection protected from light-induced retinal dysfunctions in mice. Thus, D3T protects RPE cells from UV-induced damages via activation of Akt-mTORC1-Nrf2-HO-1 signaling axis.
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Abstract
In addition to oxidative phosphorylation (OXPHOS), mitochondria perform other functions such as heme biosynthesis and oxygen sensing and mediate calcium homeostasis, cell growth, and cell death. They participate in cell communication and regulation of inflammation and are important considerations in aging, drug toxicity, and pathogenesis. The cell's capacity to maintain its mitochondria involves intramitochondrial processes, such as heme and protein turnover, and those involving entire organelles, such as fusion, fission, selective mitochondrial macroautophagy (mitophagy), and mitochondrial biogenesis. The integration of these processes exemplifies mitochondrial quality control (QC), which is also important in cellular disorders ranging from primary mitochondrial genetic diseases to those that involve mitochondria secondarily, such as neurodegenerative, cardiovascular, inflammatory, and metabolic syndromes. Consequently, mitochondrial biology represents a potentially useful, but relatively unexploited area of therapeutic innovation. In patients with genetic OXPHOS disorders, the largest group of inborn errors of metabolism, effective therapies, apart from symptomatic and nutritional measures, are largely lacking. Moreover, the genetic and biochemical heterogeneity of these states is remarkably similar to those of certain acquired diseases characterized by metabolic and oxidative stress and displaying wide variability. This biologic variability reflects cell-specific and repair processes that complicate rational pharmacological approaches to both primary and secondary mitochondrial disorders. However, emerging concepts of mitochondrial turnover and dynamics along with new mitochondrial disease models are providing opportunities to develop and evaluate mitochondrial QC-based therapies. The goals of such therapies extend beyond amelioration of energy insufficiency and tissue loss and entail cell repair, cell replacement, and the prevention of fibrosis. This review summarizes current concepts of mitochondria as disease elements and outlines novel strategies to address mitochondrial dysfunction through the stimulation of mitochondrial biogenesis and quality control.
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Affiliation(s)
- Hagir B Suliman
- Departments of Medicine (C.A.P.), Anesthesiology (H.B.S.), Duke Cancer Institute (H.B.S.), and Pathology (C.A.P.), Duke University Medical Center, Durham North Carolina
| | - Claude A Piantadosi
- Departments of Medicine (C.A.P.), Anesthesiology (H.B.S.), Duke Cancer Institute (H.B.S.), and Pathology (C.A.P.), Duke University Medical Center, Durham North Carolina
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The Nrf2/HO-1 Axis in Cancer Cell Growth and Chemoresistance. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2015; 2016:1958174. [PMID: 26697129 PMCID: PMC4677237 DOI: 10.1155/2016/1958174] [Citation(s) in RCA: 204] [Impact Index Per Article: 22.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/24/2015] [Revised: 08/13/2015] [Accepted: 08/18/2015] [Indexed: 12/20/2022]
Abstract
The transcription factor, nuclear factor erythroid 2 p45-related factor 2 (Nrf2), acts as a sensor of oxidative or electrophilic stresses and plays a pivotal role in redox homeostasis. Oxidative or electrophilic agents cause a conformational change in the Nrf2 inhibitory protein Keap1 inducing the nuclear translocation of the transcription factor which, through its binding to the antioxidant/electrophilic response element (ARE/EpRE), regulates the expression of antioxidant and detoxifying genes such as heme oxygenase 1 (HO-1). Nrf2 and HO-1 are frequently upregulated in different types of tumours and correlate with tumour progression, aggressiveness, resistance to therapy, and poor prognosis. This review focuses on the Nrf2/HO-1 stress response mechanism as a promising target for anticancer treatment which is able to overcome resistance to therapies.
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Murata H, Takamatsu H, Liu S, Kataoka K, Huh NH, Sakaguchi M. NRF2 Regulates PINK1 Expression under Oxidative Stress Conditions. PLoS One 2015; 10:e0142438. [PMID: 26555609 PMCID: PMC4640816 DOI: 10.1371/journal.pone.0142438] [Citation(s) in RCA: 127] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2015] [Accepted: 10/21/2015] [Indexed: 12/30/2022] Open
Abstract
Mutations of the PTEN-induced putative kinase 1 (PINK1) gene are a cause of autosomal recessive forms of Parkinson’s disease. Recent studies have revealed that PINK1 is an essential factor for controlling mitochondrial quality, and that it protects cells from oxidative stresses. Although there has been considerable progress in the elucidation of various aspects of PINK1 protein regulation such as activation, stability and degradation, the transcriptional regulation of PINK1 mRNA under stress conditions remains unclear. In this study, we found that nuclear factor (erythroid-derived 2)-like 2 (NRF2), an antioxidant transcription factor, regulates PINK1 expression under oxidative stress conditions. Damaged mitochondria arising from stress conditions induced NRF2-dependent transcription of the PINK1 gene through production of reactive oxygen species (ROS). Either an ROS scavenger or forced expression of KEAP1, a potent inhibitory partner to NRF2, restricted PINK1 expression induced by activated NRF2. Transcriptionally up-regulated PINK1 diminished oxidative stress-associated cell death. The results indicate that PINK1 expression is positively regulated by NRF2 and that the NRF2-PINK1 signaling axis is deeply involved in cell survival.
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Affiliation(s)
- Hitoshi Murata
- Department of Cell Biology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 2-5-1 Shikata-cho, Kita-ku, Okayama 700–8558, Japan
| | - Hitoshi Takamatsu
- Department of Cell Biology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 2-5-1 Shikata-cho, Kita-ku, Okayama 700–8558, Japan
| | - Sulai Liu
- Department of Cell Biology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 2-5-1 Shikata-cho, Kita-ku, Okayama 700–8558, Japan
| | - Ken Kataoka
- Department of Life Science, Faculty of Science, Okayama University of Science, 1–1 Ridai-cho, Kita-ku, Okayama 700–0005, Japan
| | - Nam-ho Huh
- Department of Cell Biology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 2-5-1 Shikata-cho, Kita-ku, Okayama 700–8558, Japan
| | - Masakiyo Sakaguchi
- Department of Cell Biology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 2-5-1 Shikata-cho, Kita-ku, Okayama 700–8558, Japan
- * E-mail:
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Lai TH, Shieh JM, Tsou CJ, Wu WB. Gold nanoparticles induce heme oxygenase-1 expression through Nrf2 activation and Bach1 export in human vascular endothelial cells. Int J Nanomedicine 2015; 10:5925-39. [PMID: 26445536 PMCID: PMC4590552 DOI: 10.2147/ijn.s88514] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
It has been reported that increased levels and activity of the heme oxygenase-1 (HO-1) protein ameliorate tissue injuries. In the present study, we investigated the effects and mechanisms of action of gold nanoparticles (AuNPs) on HO-1 protein expression in human vascular endothelial cells (ECs). The AuNPs induced HO-1 protein and mRNA expression in a concentration- and time-dependent manner. The induction was reduced by the thiol-containing antioxidants, including N-acetylcysteine and glutathione, but not by the non-thiol-containing antioxidants and inhibitors that block the enzymes for intracellular reactive oxygen species generation. The AuNPs enhanced Nrf2 protein levels but did not affect Nrf2 mRNA expression. In response to the AuNP treatment, the cytosolic Nrf2 translocated to the nucleus, and, concomitantly, Bach1 exited the nucleus and its tyrosine phosphorylation increased. The chromatin immunoprecipitation assay revealed that the translocated Nrf2 bound to the antioxidant-response element located in the E2 enhancer region of the HO-1 gene promoter and acted as a transcription factor. Although N-acetylcysteine inhibited the AuNP-induced Nrf2 nuclear translocation, the AuNPs did not promote intracellular reactive oxygen species production or endoplasmic reticulum stress in the ECs. Knockdown of Nrf2 expression by RNA interference significantly inhibited AuNP-induced HO-1 expression at the protein and mRNA levels. In summary, AuNPs enhance the levels and nuclear translocation of the Nrf2 protein and Bach1 export/tyrosine phosphorylation, leading to Nrf2 binding to the HO-1 E2 enhancer promoter region to drive HO-1 expression in ECs. This study, together with our parallel findings, demonstrates that AuNPs can act as an HO-1 inducer, which may partially contribute to their anti-inflammatory bioactivity in human vascular ECs.
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Affiliation(s)
- Tsung-Hsuan Lai
- School of Medicine, Fu-Jen Catholic University, New Taipei City, Taiwan ; Department of Obstetrics and Gynecology, Cathay General Hospital, Taipei, Taiwan ; Institute of Systems Biology and Bioinformatics, National Central University, Jhongli City, Taiwan
| | - Jiunn-Min Shieh
- Department of Internal Medicine, Chi-Mei Medical Center, Tainan, Taiwan ; Department of Recreation and Healthcare Management, Chia Nan University of Pharmacy and Science, Tainan, Taiwan
| | - Chih-Jen Tsou
- School of Medicine, Fu-Jen Catholic University, New Taipei City, Taiwan
| | - Wen-Bin Wu
- School of Medicine, Fu-Jen Catholic University, New Taipei City, Taiwan
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Orena S, Owen J, Jin F, Fabian M, Gillitt ND, Zeisel SH. Extracts of Fruits and Vegetables Activate the Antioxidant Response Element in IMR-32 Cells. J Nutr 2015; 145:2006-11. [PMID: 26224749 DOI: 10.3945/jn.115.216705] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2015] [Accepted: 07/08/2015] [Indexed: 01/02/2023] Open
Abstract
BACKGROUND The biological effects of antioxidant nutrients are mediated in part by activation of antioxidant response elements (AREs) on genes for enzymes involved in endogenous pathways that prevent free radical damage. Traditional approaches for identifying antioxidant molecules in foods, such as total phenolic compound (TP) content or oxygen radical absorption capacity (ORAC), do not measure capacity to activate AREs. OBJECTIVES The goal of this study was to develop an assay to assess the ARE activation capacity of fruit and vegetable extracts and determine whether such capacity was predicted by TP content and/or ORAC activity. METHODS Fruits and vegetables were homogenized, extracted with acidified ethanol, lyophilized, and resuspended in growth medium. Human IMR-32 neuroblastoma cells, transfected with an ARE-firefly luciferase reporter, were exposed to extracts for 5 h. Firefly luciferase was normalized to constitutively expressed Renilla luciferase with tertiary butylhydroquinone (tBHQ) as a positive control. TP content and ORAC activity were measured for each extract. Relations between TPs and ORAC and ARE activity were determined. RESULTS A total of 107 of 134 extracts tested significantly activated the ARE-luciferase reporter from 1.2- to 58-fold above that of the solvent control (P < 0.05) in human IMR-32 cells. ARE activity, TP content, and ORAC ranked higher in peels than in associated flesh. Despite this relation, ARE activity did not correlate with TP content (Spearman ρ = 0.05, P = 0.57) and only modestly but negatively correlated with ORAC (Spearman ρ = -0.24, P < 0.01). Many extracts activated the ARE more than predicted by the TP content or ORAC. CONCLUSIONS The ARE reporter assay identified many active fruit and vegetable extracts in human IMR-32 cells. There are components of fruits and vegetables that activate the ARE but are not phenolic compounds and are low in ORAC. The ARE-luciferase reporter assay is likely a better predictor of the antioxidant benefits of fruits and vegetables than TP or ORAC.
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Affiliation(s)
- Stephen Orena
- University of North Carolina at Chapel Hill Nutrition Research Institute, Kannapolis, NC
| | - Jennifer Owen
- University of North Carolina at Chapel Hill Nutrition Research Institute, Kannapolis, NC
| | - Fuxia Jin
- Dole Nutrition Research Laboratory, Kannapolis, NC; and
| | - Morgan Fabian
- Dole Nutrition Research Laboratory, Kannapolis, NC; and
| | | | - Steven H Zeisel
- University of North Carolina at Chapel Hill Nutrition Research Institute, Kannapolis, NC; Department of Nutrition, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, NC
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Signorelli P, Fabiani C, Brizzolari A, Paroni R, Casas J, Fabriàs G, Rossi D, Ghidoni R, Caretti A. Natural Grape Extracts Regulate Colon Cancer Cells Malignancy. Nutr Cancer 2015; 67:494-503. [DOI: 10.1080/01635581.2015.1004591] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
- Paola Signorelli
- Department of Health Sciences, University of Milan, Milan, Italy, and San Paolo Hospital, Milan, Italy
| | - Carlotta Fabiani
- Department of Health Sciences, University of Milan, Milan, Italy, and San Paolo Hospital, Milan, Italy
| | - Andrea Brizzolari
- Department of Health Sciences, University of Milan, Milan, Italy, and San Paolo Hospital, Milan, Italy
| | - Rita Paroni
- Department of Health Sciences, University of Milan, Milan, Italy, and San Paolo Hospital, Milan, Italy
| | - Josefina Casas
- Research Unit on BioActive Molecules, Department of Biomedicinal Chemistry, Catalan Institute of Advanced Chemistry, Barcelona, Spain
| | - Gemma Fabriàs
- Research Unit on BioActive Molecules, Department of Biomedicinal Chemistry, Catalan Institute of Advanced Chemistry, Barcelona, Spain
| | - Dario Rossi
- Immobiliare Ca’ Novella srl, Alessandria, Italy
| | - Riccardo Ghidoni
- Department of Health Sciences, University of Milan, Milan, Italy, and San Paolo Hospital, Milan, Italy
| | - Anna Caretti
- Department of Health Sciences, University of Milan, Milan, Italy, and San Paolo Hospital, Milan, Italy
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Dietary pretreatment with green tea polyphenol, (-)-epigallocatechin-3-gallate reduces the bioavailability and hepatotoxicity of subsequent oral bolus doses of (-)-epigallocatechin-3-gallate. Food Chem Toxicol 2014; 76:103-8. [PMID: 25528115 DOI: 10.1016/j.fct.2014.12.009] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2014] [Revised: 12/12/2014] [Accepted: 12/14/2014] [Indexed: 01/18/2023]
Abstract
Human case-studies have reported an association between green tea-based dietary supplements and hepatotoxicity. Studies have demonstrated the hepatotoxicity of high-dose oral bolus dosing with the tea polyphenol (-)-epigallocatechin-3-gallate (EGCG) in mice and dogs. We examined the effect of pretreatment with dietary EGCG on the hepatotoxicity and bioavailability of acute oral bolus dosing with EGCG in CF-1 mice. EGCG (750 mg/kg, i.g., once daily for 3 days) increased plasma alanine aminotransferase by 80-fold, decreased both reduced (by 59%) and total (by 33%) hepatic glutathione, and increased hepatic levels of phosphorylated histone 2AX. Pretreatment with dietary EGCG (3.2 mg/g diet) for 2 weeks mitigated hepatotoxicity. Acute oral EGCG also decreased mRNA expression of glutathione reductase. Dietary pretreatment prevented these decreased and increased glutathione peroxidase (Gpx)2, Gpx3, Gpx5, and Gpx7 expression. We found that dietary EGCG reduced the plasma (57% reduction) and hepatic (71% reduction) EGCG exposure following oral bolus dosing compared to mice that were not pre-treated. Overall, it appears that EGCG can modulate its own bioavailability and that dietary treatment may reduce the toxic potential of acute high oral bolus doses of EGCG. These data may partly explain the observed variation in hepatotoxic response to green tea-containing dietary supplements.
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The role of Nrf2-mediated pathway in cardiac remodeling and heart failure. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2014; 2014:260429. [PMID: 25101151 PMCID: PMC4102082 DOI: 10.1155/2014/260429] [Citation(s) in RCA: 129] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/26/2014] [Revised: 04/12/2014] [Accepted: 04/30/2014] [Indexed: 12/30/2022]
Abstract
Heart failure (HF) is frequently the consequence of sustained, abnormal neurohormonal, and mechanical stress and remains a leading cause of death worldwide. The key pathophysiological process leading to HF is cardiac remodeling, a term referring to maladaptation to cardiac stress at the molecular, cellular, tissue, and organ levels. HF and many of the conditions that predispose one to HF are associated with oxidative stress. Increased generation of reactive oxygen species (ROS) in the heart can directly lead to increased necrosis and apoptosis of cardiomyocytes which subsequently induce cardiac remodeling and dysfunction. Nuclear factor-erythroid-2- (NF-E2-) related factor 2 (Nrf2) is a transcription factor that controls the basal and inducible expression of a battery of antioxidant genes and other cytoprotective phase II detoxifying enzymes that are ubiquitously expressed in the cardiovascular system. Emerging evidence has revealed that Nrf2 and its target genes are critical regulators of cardiovascular homeostasis via the suppression of oxidative stress, which is the key player in the development and progression of HF. The purpose of this review is to summarize evidence that activation of Nrf2 enhances endogenous antioxidant defenses and counteracts oxidative stress-associated cardiac remodeling and HF.
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20
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Tayem Y, Green CJ, Motterlini R, Foresti R. Isothiocyanate–cysteine conjugates protect renal tissue against cisplatin-induced apoptosis via induction of heme oxygenase-1. Pharmacol Res 2014; 81:1-9. [DOI: 10.1016/j.phrs.2014.01.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/10/2013] [Revised: 01/02/2014] [Accepted: 01/03/2014] [Indexed: 12/27/2022]
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Perez HL, Junnotula V, Knecht D, Nie H, Sanchez Y, Boehm JC, Booth-Genthe C, Yan H, Davis R, Callahan JF. Analytical approaches for quantification of a Nrf2 pathway activator: overcoming bioanalytical challenges to support a toxicity study. Analyst 2014; 139:1902-12. [DOI: 10.1039/c3an02216a] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Activation of the Nrf2 stress pathway is known to play an important role in the defense mechanism against electrophilic and oxidative damage to biological macromolecules (DNA, lipids, and proteins).
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Affiliation(s)
- Hermes Licea Perez
- Bioanalytical Science and Toxicokinetics
- Platform Science and Technology
- GlaxoSmithkline Pharmaceuticals
- , USA
| | - Venkatraman Junnotula
- Bioanalytical Science and Toxicokinetics
- Platform Science and Technology
- GlaxoSmithkline Pharmaceuticals
- , USA
| | - Dana Knecht
- Bioanalytical Science and Toxicokinetics
- Platform Science and Technology
- GlaxoSmithkline Pharmaceuticals
- , USA
| | - Hong Nie
- Respiratory Stress & Repair DPU
- GlaxoSmithkline Pharmaceuticals
- , USA
| | - Yolanda Sanchez
- Respiratory Stress & Repair DPU
- GlaxoSmithkline Pharmaceuticals
- , USA
| | - Jeffrey C. Boehm
- Respiratory Stress & Repair DPU
- GlaxoSmithkline Pharmaceuticals
- , USA
| | | | - Hongxing Yan
- Respiratory Stress & Repair DPU
- GlaxoSmithkline Pharmaceuticals
- , USA
| | - Roderick Davis
- Respiratory Stress & Repair DPU
- GlaxoSmithkline Pharmaceuticals
- , USA
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Abstract
The Nrf2–Keap1 signaling pathway is key to cell defense and survival pathways. Nrf2 can protect cells and tissues from toxicants and carcinogens, and several Nrf2 activators are currently being tested as chemopreventive compounds. However, several studies also suggest that Nrf2 may protect cancer cells from chemotherapeutic agents and promote cancer cell proliferation. Here, Jaramillo and Zhang provide an overview of the Nrf2–Keap1 signaling pathway in cancer. They discuss the dual role of Nrf2 in cancer and the challenges in developing Nrf2-based drugs for chemoprevention and therapy. The Nrf2 (nuclear factor erythroid 2 [NF-E2]-related factor 2 [Nrf2])–Keap1 (Kelch-like erythroid cell-derived protein with CNC homology [ECH]-associated protein 1) signaling pathway is one of the most important cell defense and survival pathways. Nrf2 can protect cells and tissues from a variety of toxicants and carcinogens by increasing the expression of a number of cytoprotective genes. As a result, several Nrf2 activators are currently being tested as chemopreventive compounds in clinical trials. Just as Nrf2 protects normal cells, studies have shown that Nrf2 may also protect cancer cells from chemotherapeutic agents and facilitate cancer progression. Nrf2 is aberrantly accumulated in many types of cancer, and its expression is associated with a poor prognosis in patients. In addition, Nrf2 expression is induced during the course of drug resistance. Collectively, these studies suggest that Nrf2 contributes to both intrinsic and acquired chemoresistance. This discovery has opened up a broad spectrum of research geared toward a better understanding of the role of Nrf2 in cancer. This review provides an overview of (1) the Nrf2–Keap1 signaling pathway, (2) the dual role of Nrf2 in cancer, (3) the molecular basis of Nrf2 activation in cancer cells, and (4) the challenges in the development of Nrf2-based drugs for chemoprevention and chemotherapy.
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Abstract
Organismal life encounters reactive oxidants from internal metabolism and environmental toxicant exposure. Reactive oxygen and nitrogen species cause oxidative stress and are traditionally viewed as being harmful. On the other hand, controlled production of oxidants in normal cells serves useful purposes to regulate signaling pathways. Reactive oxidants are counterbalanced by complex antioxidant defense systems regulated by a web of pathways to ensure that the response to oxidants is adequate for the body's needs. A recurrent theme in oxidant signaling and antioxidant defense is reactive cysteine thiol-based redox signaling. The nuclear factor erythroid 2-related factor 2 (Nrf2) is an emerging regulator of cellular resistance to oxidants. Nrf2 controls the basal and induced expression of an array of antioxidant response element-dependent genes to regulate the physiological and pathophysiological outcomes of oxidant exposure. This review discusses the impact of Nrf2 on oxidative stress and toxicity and how Nrf2 senses oxidants and regulates antioxidant defense.
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Affiliation(s)
- Qiang Ma
- Receptor Biology Laboratory, Toxicology and Molecular Biology Branch, Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention.
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Recent Progress in 1,2-Dithiole-3-thione Chemistry. ADVANCES IN HETEROCYCLIC CHEMISTRY 2013. [DOI: 10.1016/b978-0-12-407777-5.00001-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/04/2023]
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Bryan HK, Olayanju A, Goldring CE, Park BK. The Nrf2 cell defence pathway: Keap1-dependent and -independent mechanisms of regulation. Biochem Pharmacol 2012; 85:705-17. [PMID: 23219527 DOI: 10.1016/j.bcp.2012.11.016] [Citation(s) in RCA: 768] [Impact Index Per Article: 64.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2012] [Revised: 11/24/2012] [Accepted: 11/27/2012] [Indexed: 12/13/2022]
Abstract
The transcription factor Nrf2 (NF-E2-related factor 2) plays a vital role in maintaining cellular homeostasis, especially upon the exposure of cells to chemical or oxidative stress, through its ability to regulate the basal and inducible expression of a multitude of antioxidant proteins, detoxification enzymes and xenobiotic transporters. In addition, Nrf2 contributes to diverse cellular functions including differentiation, proliferation, inflammation and lipid synthesis and there is an increasing association of aberrant expression and/or function of Nrf2 with pathologies including cancer, neurodegeneration and cardiovascular disease. The activity of Nrf2 is primarily regulated via its interaction with Keap1 (Kelch-like ECH-associated protein 1), which directs the transcription factor for proteasomal degradation. Although it is generally accepted that modification (e.g. chemical adduction, oxidation, nitrosylation or glutathionylation) of one or more critical cysteine residues in Keap1 represents a likely chemico-biological trigger for the activation of Nrf2, unequivocal evidence for such a phenomenon remains elusive. An increasing body of literature has revealed alternative mechanisms of Nrf2 regulation, including phosphorylation of Nrf2 by various protein kinases (PKC, PI3K/Akt, GSK-3β, JNK), interaction with other protein partners (p21, caveolin-1) and epigenetic factors (micro-RNAs -144, -28 and -200a, and promoter methylation). These and other processes are potentially important determinants of Nrf2 activity, and therefore may contribute to the maintenance of cellular homeostasis. Here, we dissect evidence supporting these Keap1-dependent and -independent mechanisms of Nrf2 regulation. Furthermore, we highlight key knowledge gaps in this important field of biology, and suggest how these may be addressed experimentally.
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Affiliation(s)
- Holly K Bryan
- MRC Centre for Drug Safety Science, Molecular & Clinical Pharmacology, Institute of Translational Medicine, University of Liverpool, L69 3GE, UK
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26
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Cho HY, van Houten B, Wang X, Miller-DeGraff L, Fostel J, Gladwell W, Perrow L, Panduri V, Kobzik L, Yamamoto M, Bell DA, Kleeberger SR. Targeted deletion of nrf2 impairs lung development and oxidant injury in neonatal mice. Antioxid Redox Signal 2012; 17:1066-82. [PMID: 22400915 PMCID: PMC3423869 DOI: 10.1089/ars.2011.4288] [Citation(s) in RCA: 77] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
AIMS Nrf2 is an essential transcription factor for protection against oxidant disorders. However, its role in organ development and neonatal disease has received little attention. Therapeutically administered oxygen has been considered to contribute to bronchopulmonary dysplasia (BPD) in prematurity. The current study was performed to determine Nrf2-mediated molecular events during saccular-to-alveolar lung maturation, and the role of Nrf2 in the pathogenesis of hyperoxic lung injury using newborn Nrf2-deficient (Nrf2(-/-)) and wild-type (Nrf2(+/+)) mice. RESULTS Pulmonary basal expression of cell cycle, redox balance, and lipid/carbohydrate metabolism genes was lower while lymphocyte immunity genes were more highly expressed in Nrf2(-/-) neonates than in Nrf2(+/+) neonates. Hyperoxia-induced phenotypes, including mortality, arrest of saccular-to-alveolar transition, and lung edema, and inflammation accompanying DNA damage and tissue oxidation were significantly more severe in Nrf2(-/-) neonates than in Nrf2(+/+) neonates. During lung injury pathogenesis, Nrf2 orchestrated expression of lung genes involved in organ injury and morphology, cellular growth/proliferation, vasculature development, immune response, and cell-cell interaction. Bioinformatic identification of Nrf2 binding motifs and augmented hyperoxia-induced inflammation in genetically deficient neonates supported Gpx2 and Marco as Nrf2 effectors. INNOVATION This investigation used lung transcriptomics and gene targeted mice to identify novel molecular events during saccular-to-alveolar stage transition and to elucidate Nrf2 downstream mechanisms in protection from hyperoxia-induced injury in neonate mouse lungs. CONCLUSION Nrf2 deficiency augmented lung injury and arrest of alveolarization caused by hyperoxia during the newborn period. Results suggest a therapeutic potential of specific Nrf2 activators for oxidative stress-associated neonatal disorders including BPD.
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Affiliation(s)
- Hye-Youn Cho
- Laboratory of Respiratory Biology, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina 27709, USA.
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Lee JH, Khor TO, Shu L, Su ZY, Fuentes F, Kong ANT. Dietary phytochemicals and cancer prevention: Nrf2 signaling, epigenetics, and cell death mechanisms in blocking cancer initiation and progression. Pharmacol Ther 2012; 137:153-71. [PMID: 23041058 DOI: 10.1016/j.pharmthera.2012.09.008] [Citation(s) in RCA: 160] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2012] [Accepted: 09/17/2012] [Indexed: 02/06/2023]
Abstract
Reactive metabolites from carcinogens and oxidative stress can drive genetic mutations, genomic instability, neoplastic transformation, and ultimately carcinogenesis. Numerous dietary phytochemicals in vegetables/fruits have been shown to possess cancer chemopreventive effects in both preclinical animal models and human epidemiological studies. These phytochemicals could prevent the initiation of carcinogenesis via either direct scavenging of reactive oxygen species/reactive nitrogen species (ROS/RNS) or, more importantly, the induction of cellular defense detoxifying/antioxidant enzymes. These defense enzymes mediated by Nrf2-antioxidative stress and anti-inflammatory signaling pathways can contribute to cellular protection against ROS/RNS and reactive metabolites of carcinogens. In addition, these compounds would kill initiated/transformed cancer cells in vitro and in in vivo xenografts via diverse anti-cancer mechanisms. These mechanisms include the activation of signaling kinases (e.g., JNK), caspases and the mitochondria damage/cytochrome c pathways. Phytochemicals may also have anti-cancer effects by inhibiting the IKK/NF-κB pathway, inhibiting STAT3, and causing cell cycle arrest. In addition, other mechanisms may include epigenetic alterations (e.g., inhibition of HDACs, miRNAs, and the modification of the CpG methylation of cancer-related genes). In this review, we will discuss: the current advances in the study of Nrf2 signaling; Nrf2-deficient tumor mouse models; the epigenetic control of Nrf2 in tumorigenesis and chemoprevention; Nrf2-mediated cancer chemoprevention by naturally occurring dietary phytochemicals; and the mutation or hyper-expression of the Nrf2-Keap1 signaling pathway in advanced tumor cells. The future development of dietary phytochemicals for chemoprevention must integrate in vitro signaling mechanisms, relevant biomarkers of human diseases, and combinations of different phytochemicals and/or non-toxic therapeutic drugs, including NSAIDs.
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Affiliation(s)
- Jong Hun Lee
- Center for Cancer Prevention Research, Department of Pharmaceutics, Ernest-Mario School of Pharmacy, Rutgers, the State University of New Jersey, 160 Frelinghuysen Road, Piscataway, NJ 08854, USA
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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: 244] [Impact Index Per Article: 20.3] [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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Abstract
Mitochondrial dysfunction contributes to the pathophysiology of acute neurologic disorders and neurodegenerative diseases. Bioenergetic failure is the primary cause of acute neuronal necrosis, and involves excitotoxicity-associated mitochondrial Ca(2+) overload, resulting in opening of the inner membrane permeability transition pore and inhibition of oxidative phosphorylation. Mitochondrial energy metabolism is also very sensitive to inhibition by reactive O(2) and nitrogen species, which modify many mitochondrial proteins, lipids, and DNA/RNA, thus impairing energy transduction and exacerbating free radical production. Oxidative stress and Ca(2+)-activated calpain protease activities also promote apoptosis and other forms of programmed cell death, primarily through modification of proteins and lipids present at the outer membrane, causing release of proapoptotic mitochondrial proteins, which initiate caspase-dependent and caspase-independent forms of cell death. This review focuses on three classifications of mitochondrial targets for neuroprotection. The first is mitochondrial quality control, maintained by the dynamic processes of mitochondrial fission and fusion and autophagy of abnormal mitochondria. The second includes targets amenable to ischemic preconditioning, e.g., electron transport chain components, ion channels, uncoupling proteins, and mitochondrial biogenesis. The third includes mitochondrial proteins and other molecules that defend against oxidative stress. Each class of targets exhibits excellent potential for translation to clinical neuroprotection.
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Affiliation(s)
- Miguel A Perez-Pinzon
- Department of Neurology, Cerebral Vascular Disease Research Center, University of Miami Miller School of Medicine, Miami, FL, USA
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Tesei A, Brigliadori G, Carloni S, Fabbri F, Ulivi P, Arienti C, Sparatore A, Del Soldato P, Pasini A, Amadori D, Silvestrini R, Zoli W. Organosulfur derivatives of the HDAC inhibitor valproic acid sensitize human lung cancer cell lines to apoptosis and to cisplatin cytotoxicity. J Cell Physiol 2012; 227:3389-96. [DOI: 10.1002/jcp.24039] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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31
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Pan H, Wang H, Zhu L, Mao L, Qiao L, Su X. The role of Nrf2 in migration and invasion of human glioma cell U251. World Neurosurg 2011; 80:363-70. [PMID: 22120303 DOI: 10.1016/j.wneu.2011.06.063] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2011] [Revised: 04/25/2011] [Accepted: 06/29/2011] [Indexed: 12/13/2022]
Abstract
OBJECTIVE NF-E2-related factor 2 (Nrf2) is a transcription factor that is related to tumor cell multidrug resistance and proliferation. Here we studied the involvement of Nrf2 in the migration and invasion of human U251 glioma cells. METHODS Two kinds of plasmid, that is, pEGFP-Nrf2 and Si-Nrf2, were constructed and transfected to upregulate or downregulate the expression of Nrf2 in U251 glioma cell line. Blank vectors or random siRNA plasmid were used as negative control. Cells treated with lipofectamine only were set up as blank control. Protein and mRNA level of Nrf2 and matrix metalloproteinase 9 (MMP9) were investigated by reverse transcriptase-polymerase chain reaction and western blot after transfection. Wound healing assay and transwell assay were used to study migration and invasion of U251 after transfection. Gelatin zymography was performed to reveal the change of MMP9 activity after transfection. RESULTS The mRNA and protein level of Nrf2 was upregulated in U251-pEGFP-Nrf2 while downregulated in U251-Si-Nrf2 48 hours after transfection. In the wound healing assay, there were more cells in group pEGFP-Nrf2 crossing the scratch line than in group Si-Nrf2. Furthermore, in transwell migration and invasion assay, there were more cells in group pEGFP-Nrf2 penetrating the membranes than in group Si-Nrf2. Then we investigated the change of MMP9 activity, mRNA, and protein levels after transfection. The results suggested that upregulation of Nrf2 led to an increase in MMP9 expression and activity whereas downregulation of Nrf2 led to a decrease in MMP9 expression and activity. CONCLUSION Nrf2 is involved in migration and invasion of U251 cells, which may be related to MMP9.
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Affiliation(s)
- Hao Pan
- Department of Neurosurgery, Jinling Hospital, School of Medicine, Nanjing University, Nanjing, People's Republic of China
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Zheng H, Whitman SA, Wu W, Wondrak GT, Wong PK, Fang D, Zhang DD. Therapeutic potential of Nrf2 activators in streptozotocin-induced diabetic nephropathy. Diabetes 2011; 60:3055-66. [PMID: 22025779 PMCID: PMC3198067 DOI: 10.2337/db11-0807] [Citation(s) in RCA: 413] [Impact Index Per Article: 31.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
OBJECTIVE To determine whether dietary compounds targeting NFE2-related factor 2 (Nrf2) activation can be used to attenuate renal damage and preserve renal function during the course of streptozotocin (STZ)-induced diabetic nephropathy. RESEARCH DESIGN AND METHODS Diabetes was induced in Nrf2(+/+) and Nrf2(-/-) mice by STZ injection. Sulforaphane (SF) or cinnamic aldehyde (CA) was administered 2 weeks after STZ injection and metabolic indices and renal structure and function were assessed (18 weeks). Markers of diabetes including blood glucose, insulin, polydipsia, polyuria, and weight loss were measured. Pathological alterations and oxidative damage in glomeruli were also determined. Changes in protein expression of the Nrf2 pathway, as well as transforming growth factor-β1 (TGF-β1), fibronectin (FN), collagen IV, and p21/WAF1Cip1 (p21) were analyzed. The molecular mechanisms of Nrf2-mediated protection were investigated in an in vitro model using human renal mesangial cells (HRMCs). RESULTS SF or CA significantly attenuated common metabolic disorder symptoms associated with diabetes in Nrf2(+/+) but not in Nrf2(-/-) mice, indicating SF and CA function through specific activation of the Nrf2 pathway. Furthermore, SF or CA improved renal performance and minimized pathological alterations in the glomerulus of STZ-Nrf2(+/+) mice. Nrf2 activation reduced oxidative damage and suppressed the expression of TGF-β1, extracellular matrix proteins and p21 both in vivo and in HRMCs. In addition, Nrf2 activation reverted p21-mediated growth inhibition and hypertrophy of HRMCs under hyperglycemic conditions. CONCLUSIONS We provide experimental evidence indicating that dietary compounds targeting Nrf2 activation can be used therapeutically to improve metabolic disorder and relieve renal damage induced by diabetes.
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Affiliation(s)
- Hongting Zheng
- Department of Pharmacology and Toxicology, University of Arizona, Tucson, Arizona
- Department of Endocrinology, Xinqiao Hospital, Third Military Medical University, Chongqing, China
| | - Samantha A. Whitman
- Department of Pharmacology and Toxicology, University of Arizona, Tucson, Arizona
| | - Wei Wu
- Department of Pharmacology and Toxicology, University of Arizona, Tucson, Arizona
- Department of Endocrinology, Xinqiao Hospital, Third Military Medical University, Chongqing, China
| | - Georg T. Wondrak
- Department of Pharmacology and Toxicology, University of Arizona, Tucson, Arizona
| | - Pak K. Wong
- Department of Aerospace and Mechanical Engineering, University of Arizona, Tucson, Arizona
| | - Deyu Fang
- Department of Pathology, School of Medicine, Northwestern University, Chicago, Illinois
| | - Donna D. Zhang
- Department of Pharmacology and Toxicology, University of Arizona, Tucson, Arizona
- Corresponding author: Donna Zhang,
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Pathobiology and chemoprevention of bladder cancer. JOURNAL OF ONCOLOGY 2011; 2011:528353. [PMID: 21941546 PMCID: PMC3175393 DOI: 10.1155/2011/528353] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/01/2011] [Accepted: 07/14/2011] [Indexed: 01/16/2023]
Abstract
Our understanding of the pathogenesis of bladder cancer has improved considerably over the past decade. Translating these novel pathobiological discoveries into therapies, prevention, or strategies to manage patients who are suspected to have or who have been diagnosed with bladder cancer is the ultimate goal. In particular, the chemoprevention of bladder cancer development is important, since urothelial cancer frequently recurs, even if the primary cancer is completely removed. The numerous alterations of both oncogenes and tumor suppressor genes that have been implicated in bladder carcinogenesis represent novel targets for therapy and prevention. In addition, knowledge about these genetic alterations will help provide a better understanding of the biological significance of preneoplastic lesions of bladder cancer. Animal models for investigating bladder cancer development and prevention can also be developed based on these alterations. This paper summarizes the results of recent preclinical and clinical chemoprevention studies and discusses screening for bladder cancer.
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Zhu Q, Sun Z, Jiang Y, Chen F, Wang M. Acrolein scavengers: reactivity, mechanism and impact on health. Mol Nutr Food Res 2011; 55:1375-90. [PMID: 21714129 DOI: 10.1002/mnfr.201100149] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2011] [Revised: 04/14/2011] [Accepted: 04/26/2011] [Indexed: 01/28/2023]
Abstract
Acrolein (ACR) is an α,β-unsaturated aldehyde that exists extensively in the environment and (thermally processed) foods. It can also be generated through endogenous metabolism. Its high electrophilicity makes this aldehyde notorious for its facile reaction with biological nucleophiles, leading to the modification of proteins/DNA and depletion of glutathione. Recent studies also have revealed its roles in disturbing various cell signing pathways in biological systems. With growing evidences of ACR's implication in human diseases, strategies to eliminate its hazardous impacts are of great importance. One of the intervention strategies is the application of reactive scavengers to directly trap ACR. Some known ACR scavengers include sulfur (thiol)-containing and nitrogen (amino)-containing compounds as well as the newly emerging natural polyphenols. In this review, the interactions between ACR and its scavengers are highlighted. The discussion about ACR scavengers is mainly focused on their chemical reactivity, trapping mechanisms as well as their roles extended to biological relevance. In addition to their direct trapping effect on ACR, these scavengers might possess multiple functions and offer additional benefits against ACR-induced toxicity. A comprehensive understanding of the mechanism involved may help to establish ACR scavenging as a novel therapeutic intervention against human diseases that are associated with ACR and/or oxidative stress.
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Affiliation(s)
- Qin Zhu
- School of Biological Sciences, The University of Hong Kong, Hong Kong, PR China
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Greco T, Fiskum G. Brain mitochondria from rats treated with sulforaphane are resistant to redox-regulated permeability transition. J Bioenerg Biomembr 2011; 42:491-7. [PMID: 21061051 DOI: 10.1007/s10863-010-9312-9] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2010] [Accepted: 10/21/2010] [Indexed: 11/25/2022]
Abstract
Oxidative stress promotes Ca2+-dependent opening of the mitochondrial inner membrane permeability transition pore (PTP), causing bioenergetic failure and subsequent cell death in many paradigms, including those related to acute brain injury. One approach to pre-conditioning against oxidative stress is pharmacologic activation of the Nrf2/ARE pathway of antioxidant gene expression by agents such as sulforaphane (SFP). This study tested the hypothesis that administration of SFP to normal rats increases resistance of isolated brain mitochondria to redox-sensitive PTP opening. SFP or DMSO vehicle was administered intraperitoneally to adult male rats at 10 mg/kg 40 h prior to isolation of non-synaptic brain mitochondria. Mitochondria were suspended in medium containing a respiratory substrate and were exposed to an addition of Ca2+ below the threshold for PTP opening. Subsequent addition of tert-butyl hydroperoxide (tBOOH) resulted in a cyclosporin A-inhibitable release of accumulated Ca2+ into the medium, as monitored by an increase in fluorescence of Calcium Green 5N within the medium, and was preceded by a decrease in the autofluorescence of mitochondrial NAD(P)H. SFP treatment significantly reduced the rate of tBOOH-induced Ca2+ release but did not affect NAD(P)H oxidation or inhibit PTP opening induced by the addition of phenylarsine oxide, a direct sulfhydryl oxidizing agent. SFP treatment had no effect on respiration by brain mitochondria and had no effect on PTP opening or respiration when added directly to isolated mitochondria. We conclude that SFP confers resistance of brain mitochondria to redox-regulated PTP opening, which could contribute to neuroprotection observed with SFP.
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Affiliation(s)
- Tiffany Greco
- Department of Anesthesiology and the Center for Shock, Trauma, and Anesthesiology Research, Baltimore, MD, USA
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Hirotsu Y, Katsuoka F, Itoh K, Yamamoto M. Nrf2 degron-fused reporter system: a new tool for specific evaluation of Nrf2 inducers. Genes Cells 2011; 16:406-15. [PMID: 21392184 DOI: 10.1111/j.1365-2443.2011.01496.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The transcription factor Nrf2 is degraded through the proteasome pathway, but is stabilized in response to oxidative and electrophilic stresses, and activates cytoprotective enzyme genes through binding to the antioxidant/electrophile response element (ARE/EpRE). Nrf2 inducers thus have considerable potential as therapeutic drugs. Although ARE-driven reporters are commonly employed to validate Nrf2 inducers, these reporters are relatively nonspecific. We have generated a new reporter, Nrf2d-LacZ, which may prove to be a better tool for validation of Nrf2 inducers. We made the Nrf2d-LacZ reporter by fusing the N-terminus of Nrf2 harboring a Neh2 degron to β-galactosidase (LacZ), and compared its activity in immortalized mouse embryo fibroblasts (MEFs) with conventional ARE-luciferase (ARE-Luc) reporters in 293T cells, and in MEFs. Nrf2d-LacZ was degraded in unstressed conditions, but stabilized upon exposure to stresses. LacZ activity was induced by electrophiles in a dose-dependent manner, and the induction was detected much more rapidly compared with ARE-Luc. Nrf2d-LacZ was activated not only by electrophiles but also by a variety of other Nrf2 inducing stresses. Although ARE-Luc was activated by 12-O-Tetradecanoylphorbol 13-acetate in an Nrf2-independent manner, Nrf2d-LacZ was not activated by TPA, thus emphasizing the specificity of the Nrf2d-LacZ reporter system for validation of Nrf2 inducers.
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Affiliation(s)
- Yosuke Hirotsu
- Department of Medical Biochemistry, Tohoku University Graduate School of Medicine, Aoba-ku, Sendai 980-8575, Japan
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Tufekci KU, Civi Bayin E, Genc S, Genc K. The Nrf2/ARE Pathway: A Promising Target to Counteract Mitochondrial Dysfunction in Parkinson's Disease. PARKINSONS DISEASE 2011; 2011:314082. [PMID: 21403858 PMCID: PMC3049335 DOI: 10.4061/2011/314082] [Citation(s) in RCA: 85] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/30/2010] [Revised: 11/25/2010] [Accepted: 01/03/2011] [Indexed: 12/29/2022]
Abstract
Mitochondrial dysfunction is a prominent feature of various neurodegenerative diseases as strict regulation of integrated mitochondrial functions is essential for neuronal signaling, plasticity, and transmitter release. Many lines of evidence suggest that mitochondrial dysfunction plays a central role in the pathogenesis of Parkinson's disease (PD). Several PD-associated genes interface with mitochondrial dynamics regulating the structure and function of the mitochondrial network. Mitochondrial dysfunction can induce neuron death through a plethora of mechanisms. Both mitochondrial dysfunction and neuroinflammation, a common denominator of PD, lead to an increased production of reactive oxygen species, which are detrimental to neurons. The transcription factor nuclear factor E2-related factor 2 (Nrf2, NFE2L2) is an emerging target to counteract mitochondrial dysfunction and its consequences in PD. Nrf2 activates the antioxidant response element (ARE) pathway, including a battery of cytoprotective genes such as antioxidants and anti-inflammatory genes and several transcription factors involved in mitochondrial biogenesis. Here, the current knowledge about the role of mitochondrial dysfunction in PD, Nrf2/ARE stress-response mechanisms, and the evidence for specific links between this pathway and PD are summarized. The neuroprotection of nigral dopaminergic neurons by the activation of Nrf2 through several inducers in PD is also emphasized as a promising therapeutic approach.
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Affiliation(s)
- Kemal Ugur Tufekci
- Department of Neuroscience, Health Science Institute, Dokuz Eylul University, Inciralti, 35340 Izmir, Turkey
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Hu R, Saw CLL, Yu R, Kong ANT. Regulation of NF-E2-related factor 2 signaling for cancer chemoprevention: antioxidant coupled with antiinflammatory. Antioxid Redox Signal 2010; 13:1679-98. [PMID: 20486765 PMCID: PMC2966483 DOI: 10.1089/ars.2010.3276] [Citation(s) in RCA: 152] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Cancer chemoprevention is a process of using either natural or synthetic compounds to reduce the risk of developing cancer. Observations that NF-E2-related factor 2 (Nrf2)-deficient mice lack response to some chemopreventive agents point to the important role of Nrf2 in chemoprevention. Nrf2 is a member of basic-leucine zipper transcription factor family and has been shown to regulate gene expression by binding to a response element, antioxidant responsive element. It is generally believed that activation of Nrf2 signaling is an adaptive response to the environmental and endogenous stresses. Under homeostatic conditions, Nrf2 is suppressed by association with Kelch-like ECH-associated protein 1 (Keap1), but is stimulated upon exposure to oxidative or electrophilic stress. Once activated, Nrf2 translocates into nuclei and upregulates a group of genes that act in concert to combat oxidative stress. Nrf2 is also shown to have protective function against inflammation, a pathological process that could contribute to carcinogenesis. In this review, we will discuss the current progress in the study of Nrf2 signaling, in particular, the mechanisms of Nrf2 activation by chemopreventive agents. We will also discuss some of the potential caveats of Nrf2 in cancer treatment and future opportunity and challenges on regulation of Nrf2-mediated antioxidant and antiinflammatory signaling in the context of cancer prevention.
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Affiliation(s)
- Rong Hu
- Department of Physiology, China Pharmaceutical University, Nanjing, China.
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Calkins MJ, Vargas MR, Johnson DA, Johnson JA. Astrocyte-specific overexpression of Nrf2 protects striatal neurons from mitochondrial complex II inhibition. Toxicol Sci 2010; 115:557-68. [PMID: 20211941 DOI: 10.1093/toxsci/kfq072] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Nuclear factor E2-related factor 2 (Nrf2) is a transcription factor that is known to regulate a variety of cytoprotective genes through the antioxidant response element (ARE). This endogenous response is one of the major pathways by which cells are protected from xenobiotic or innate oxidative insults. Furthermore, in neural systems, astrocyte-specific activation of Nrf2 is known to protect neurons. In previous work, our laboratory found that Nrf2 protects from intrastriatal injections of the mitochondrial complex II inhibitor malonate. Here, we extend these results to show that multiple methods of astrocyte-specific Nrf2 overexpression provide protection from neurotoxicity in vivo. GFAP-Nrf2 transgenic mice are significantly more resistant to malonate lesioning. This outcome is associated with an increased basal resistance, but more so, an enhanced Nrf2 response to lesioning that attenuated the ensuing neurotoxicity. Furthermore, striatal transplantation of neuroprogenitor cells overexpressing Nrf2 that differentiate into astrocytes after grafting also significantly reduced malonate toxicity. Overall, these data establish that enhanced astrocytic Nrf2 response and Nrf2 preconditioning are both sufficient to protect from acute lesions from mitochondrial complex II inhibition.
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Affiliation(s)
- Marcus J Calkins
- Molecular and Environmental Toxicology Center, University of Wisconsin, Madison, Wisconsin 53705, USA
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40
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Jia Y, Wu SL, Isenberg JS, Dai S, Sipes JM, Field L, Zeng B, Bandle RW, Ridnour LA, Wink DA, Ramchandran R, Karger BL, Roberts DD. Thiolutin inhibits endothelial cell adhesion by perturbing Hsp27 interactions with components of the actin and intermediate filament cytoskeleton. Cell Stress Chaperones 2010; 15:165-81. [PMID: 19579057 PMCID: PMC2866983 DOI: 10.1007/s12192-009-0130-0] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2009] [Revised: 06/12/2009] [Accepted: 06/17/2009] [Indexed: 10/20/2022] Open
Abstract
Thiolutin is a dithiole synthesized by Streptomyces sp. that inhibits endothelial cell adhesion and tumor growth. We show here that thiolutin potently inhibits developmental angiogenesis in zebrafish and vascular outgrowth from tissue explants in 3D cultures. Thiolutin is a potent and selective inhibitor of endothelial cell adhesion accompanied by rapid induction of HSPB1 (Hsp27) phosphorylation. The inhibitory effects of thiolutin on endothelial cell adhesion are transient, potentially due to a compensatory increase in Hsp27 protein levels. Accordingly, heat shock induction of Hsp27 limits the anti-adhesive activity of thiolutin. Thiolutin treatment results in loss of actin stress fibers, increased cortical actin as cells retract, and decreased cellular F-actin. Mass spectrometric analysis of Hsp27 binding partners following immunoaffinity purification identified several regulatory components of the actin cytoskeleton that associate with Hsp27 in a thiolutin-sensitive manner including several components of the Arp2/3 complex. Among these, ArpC1a is a direct binding partner of Hsp27. Thiolutin treatment induces peripheral localization of phosphorylated Hsp27 and Arp2/3. Hsp27 also associates with the intermediate filament components vimentin and nestin. Thiolutin treatment specifically ablates Hsp27 interaction with nestin and collapses nestin filaments. These results provide new mechanistic insights into regulation of cell adhesion and cytoskeletal dynamics by Hsp27.
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Affiliation(s)
- Yifeng Jia
- Laboratory of Pathology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892 USA
| | - Shiaw-Lin Wu
- Barnett Institute, Northeastern University, Boston, MA 02115 USA
| | - Jeff S. Isenberg
- Laboratory of Pathology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892 USA
- Hemostasis and Vascular Biology Research Institute, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261 USA
| | - Shujia Dai
- Barnett Institute, Northeastern University, Boston, MA 02115 USA
| | - John M. Sipes
- Laboratory of Pathology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892 USA
| | - Lyndsay Field
- Laboratory of Pathology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892 USA
| | - Bixi Zeng
- Laboratory of Pathology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892 USA
| | - Russell W. Bandle
- Laboratory of Pathology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892 USA
| | - Lisa A. Ridnour
- Radiation Biology Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892 USA
| | - David A. Wink
- Radiation Biology Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892 USA
| | - Ramani Ramchandran
- Laboratory of Pathology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892 USA
- Department of Pediatrics, Children’s Research Institute, Medical College of Wisconsin, Milwaukee, WI 53226 USA
| | - Barry L. Karger
- Barnett Institute, Northeastern University, Boston, MA 02115 USA
| | - David D. Roberts
- Laboratory of Pathology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892 USA
- NIH, Building 10 Room 2A33, 10 Center Dr MSC1500, Bethesda, MD 20892-1500 USA
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Klaassen CD, Reisman SA. Nrf2 the rescue: effects of the antioxidative/electrophilic response on the liver. Toxicol Appl Pharmacol 2010; 244:57-65. [PMID: 20122946 DOI: 10.1016/j.taap.2010.01.013] [Citation(s) in RCA: 303] [Impact Index Per Article: 21.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2009] [Revised: 12/23/2009] [Accepted: 01/26/2010] [Indexed: 02/06/2023]
Abstract
Nuclear factor erythroid 2-related factor 2 (Nrf2) is a transcription factor that positively regulates the basal and inducible expression of a large battery of cytoprotective genes. These gene products include proteins that catalyze reduction reactions (NAD(P)H:quinone oxidoreductase 1, Nqo1), conjugation reactions (glutathione-S-transferases, Gsts and UDP-glucuronosyltransferases, Ugts), as well as the efflux of potentially toxic xenobiotics and xenobiotic conjugates (multidrug resistance-associated proteins, Mrps). The significance of Nrf2 in the liver has been established, as livers of Nrf2-null mice are more susceptible to various oxidative/electrophilic stress-induced pathologies than wild-type mice. In contrast, both pharmacological and genetic models of hepatic Nrf2 activation are protective against oxidative/electrophilic stress. Furthermore, because certain Nrf2-target genes in the liver could affect the distribution, metabolism, and excretion of xenobiotics, the effects of Nrf2 on the kinetics of drugs and other xenobiotics should also be considered, with a special emphasis on metabolism and excretion. Therefore, this review highlights the research that has contributed to the understanding of the importance of Nrf2 in toxicodynamics and toxicokinetics, especially that which pertains to the liver.
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Affiliation(s)
- Curtis D Klaassen
- Department of Pharmacology, Toxicology, and Therapeutics, University of Kansas Medical Center, 3901 Rainbow Blvd., Kansas City, KS 66160-7417, USA.
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Gross-Steinmeyer K, Stapleton PL, Tracy JH, Bammler TK, Strom SC, Buhler DR, Eaton DL. Modulation of aflatoxin B1-mediated genotoxicity in primary cultures of human hepatocytes by diindolylmethane, curcumin, and xanthohumols. Toxicol Sci 2009; 112:303-10. [PMID: 19770484 DOI: 10.1093/toxsci/kfp206] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
This study employed cultured human primary hepatocytes to investigate the ability of the putative chemopreventive phytochemicals curcumin (CUR), 3,3'-diindolylmethane (DIM), isoxanthohumol (IXN), or 8-prenylnaringenin (8PN) to reduce DNA adduct formation of the hepatocarcinogen aflatoxin B1 (AFB). Following 48 h of pretreatment, DIM and 8PN significantly increased AFB-DNA adduct levels, whereas CUR and IXN had no effect. DIM greatly enhanced the transcriptional expression of cytochrome P450 (CYP) 1A1 and CYP1A2 mRNA. Glutathione S-transferase mRNAs were not increased by any of the treatments. In vitro enzyme activity assays demonstrated that 8PN and DIM, but not CUR or IXN, inhibited human CYP1A1, CYP1A2, and CYP3A4 activities. To distinguish between treatment effects on transcription versus direct effects on enzyme activity for DIM, we evaluated the effects of pretreatment alone (transcriptional activation) versus cotreatment alone (enzyme inhibition). The results demonstrated that effects on gene expression, but not catalytic activity, are responsible for the observed effects of DIM on AFB-DNA adduct formation. The increase in AFB-DNA damage following DIM treatment may be explained through its substantial induction of CYP1A2 and/or its downregulation of GSTM1, both of which were significant. The increase in DNA damage by DIM raises potential safety risks for dietary supplements of DIM and its precursor indole-3-carbinol.
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Affiliation(s)
- Kerstin Gross-Steinmeyer
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, Washington 98105, USA
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Restoration of leukotriene B(4)-12-hydroxydehydrogenase/15- oxo-prostaglandin 13-reductase (LTBDH/PGR) expression inhibits lung cancer growth in vitro and in vivo. Lung Cancer 2009; 68:161-9. [PMID: 19595472 DOI: 10.1016/j.lungcan.2009.06.011] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2009] [Revised: 06/11/2009] [Accepted: 06/14/2009] [Indexed: 01/29/2023]
Abstract
Leukotriene B(4)-12-hydroxydehydrogenase/15-oxo-prostaglandin 13-reductase (LTBDH/PGR) is a bifunctional enzyme capable of inactivating leukotriene B(4) (LTB(4)) and 15-oxo-prostaglandins (15-PGs). Its role in growth suppressive functions in lung cancer was studied in in vitro and in vivo systems. The LTBDH/PGR gene was expressed in lung cancer cell lines through recombinant adenovirus infection, and through a tetracycline-inducible expression system. After restoration of LTBDH/PGR expression in LTBDH/PGR-negative (H1299) or -low (A549) lung cancer cell lines, the restored enzyme induced apoptosis and growth inhibition in vitro. Ectopic expression of LTBDH/PGR caused also suppression of tumorigenicity of A549 cells in nude mice. In contrast, LTBDH/PGR over-expression in LTBDH/PGR-positive (H157) lung cancer cell line induced little apoptosis and growth inhibition. This study indicates that restoration of LTBDH/PGR expression is effective in preventing lung cancer growth in vitro and in vivo.
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Chemopreventive functions of sulforaphane: A potent inducer of antioxidant enzymes and apoptosis. J Funct Foods 2009. [DOI: 10.1016/j.jff.2008.09.002] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
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45
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Abstract
Cells exposed to oxidative stress or electrophilic xenobiotics respond by transcriptionally up-regulating a battery of genes that contain a cis-acting element in their promoter region known as the antioxidant/electrophile response element (ARE). Mutational analysis of the promoter regions of ARE-containing genes led to the creation of two different models for the ARE; a core ARE (cARE: RTGACnnnGC) and an extended ARE (eARE: TMAnnRTGAYnnnGCAwwww). Using bioinformatic software we have aligned the promoter regions of several ARE-containing genes to produce two position-specific probability matrices that independently describe the cARE and eARE. These matrices can also be used to quantitatively assess putative AREs.
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Affiliation(s)
- Donald E Nerland
- Department of Pharmacology & Toxicology, Health Sciences Center, University of Louisville, Louisville, KY, USA.
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Lau A, Villeneuve NF, Sun Z, Wong PK, Zhang DD. Dual roles of Nrf2 in cancer. Pharmacol Res 2008; 58:262-70. [PMID: 18838122 DOI: 10.1016/j.phrs.2008.09.003] [Citation(s) in RCA: 527] [Impact Index Per Article: 32.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/18/2008] [Revised: 09/07/2008] [Accepted: 09/08/2008] [Indexed: 02/07/2023]
Abstract
In response to oxidative stress, the transcription factor NF-E2-related factor 2 (Nrf2) controls the fate of cells through transcriptional upregulation of antioxidant response element (ARE)-bearing genes, including those encoding endogenous antioxidants, phase II detoxifying enzymes, and transporters. Expression of the Nrf2-dependent proteins is critical for ameliorating or eliminating toxicants/carcinogens to maintain cellular redox homeostasis. As a result, activation of the Nrf2 pathway, by naturally-occurring compounds or synthetic chemicals at sub-toxic doses, confers protection against subsequent toxic/carcinogenic exposure. Thus, the use of dietary compounds or synthetic chemicals to boost the Nrf2-dependent adaptive response to counteract environmental insults has emerged to be a promising strategy for cancer prevention. Interestingly, recent emerging data has revealed the "dark" side of Nrf2. Nrf2 and its downstream genes are overexpressed in many cancer cell lines and human cancer tissues, giving cancer cells an advantage for survival and growth. Furthermore, Nrf2 is upregulated in resistant cancer cells and is thought to be responsible for acquired chemoresistance. Therefore, it may be necessary to inhibit the Nrf2 pathway during chemotherapy. This review is primarily focused on the role of Nrf2 in cancer, with emphasis on the recent findings indicating the cancer promoting function of Nrf2 and its role in acquired chemoresistance.
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Affiliation(s)
- Alexandria Lau
- Department of Pharmacology and Toxicology, University of Arizona, Tucson, AZ 85721, USA
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Na HK, Kim EH, Jung JH, Lee HH, Hyun JW, Surh YJ. (−)-Epigallocatechin gallate induces Nrf2-mediated antioxidant enzyme expression via activation of PI3K and ERK in human mammary epithelial cells. Arch Biochem Biophys 2008; 476:171-7. [DOI: 10.1016/j.abb.2008.04.003] [Citation(s) in RCA: 198] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2008] [Revised: 03/31/2008] [Accepted: 04/01/2008] [Indexed: 01/03/2023]
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Marin-Kuan M, Cavin C, Delatour T, Schilter B. Ochratoxin A carcinogenicity involves a complex network of epigenetic mechanisms. Toxicon 2008; 52:195-202. [PMID: 18649906 DOI: 10.1016/j.toxicon.2008.04.166] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2007] [Revised: 12/18/2007] [Accepted: 04/08/2008] [Indexed: 11/28/2022]
Abstract
Ochratoxin A (OTA) is a mycotoxin occurring in a wide range of food products. Because of the limitation of human epidemiological data, the safety significance of OTA in food has to rely on animal data, with renal toxicity and carcinogenicity being considered the pivotal effects. The elucidation of the mechanism of action would improve the use of experimental animal data for risk assessment. Direct genotoxicity versus epigenetic mechanisms appears to be a key question. In the present review, the increasingly documented epigenetic cellular effects of OTA and their potential toxicological relevance are discussed. The information available suggests that OTA is unlikely to act through a single, well-defined mechanism of action. Instead, it is proposed that a network of interacting epigenetic mechanisms, including protein synthesis inhibition, oxidative stress and the activation of specific cell signalling pathways, is responsible for OTA carcinogenicity. From a risk assessment perspective, it has to be noted that the mechanisms proposed above depend mainly upon gene expression and enzyme activation, and are, therefore, likely to be thresholded.
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Affiliation(s)
- Maricel Marin-Kuan
- Nestlé Research Center, Quality and Safety, PO Box 44, Vers-chez-les-Blanc, CH-1000 Lausanne 26, Switzerland.
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Na HK, Surh YJ. Modulation of Nrf2-mediated antioxidant and detoxifying enzyme induction by the green tea polyphenol EGCG. Food Chem Toxicol 2008; 46:1271-8. [DOI: 10.1016/j.fct.2007.10.006] [Citation(s) in RCA: 315] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2007] [Revised: 09/26/2007] [Accepted: 10/03/2007] [Indexed: 10/22/2022]
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New sulfurated derivatives of valproic acid with enhanced histone deacetylase inhibitory activity. Bioorg Med Chem Lett 2008; 18:1893-7. [DOI: 10.1016/j.bmcl.2008.02.007] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2007] [Revised: 02/05/2008] [Accepted: 02/05/2008] [Indexed: 11/21/2022]
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