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Gülow K, Tümen D, Heumann P, Schmid S, Kandulski A, Müller M, Kunst C. Unraveling the Role of Reactive Oxygen Species in T Lymphocyte Signaling. Int J Mol Sci 2024; 25:6114. [PMID: 38892300 PMCID: PMC11172744 DOI: 10.3390/ijms25116114] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2024] [Revised: 05/28/2024] [Accepted: 05/30/2024] [Indexed: 06/21/2024] Open
Abstract
Reactive oxygen species (ROS) are central to inter- and intracellular signaling. Their localized and transient effects are due to their short half-life, especially when generated in controlled amounts. Upon T cell receptor (TCR) activation, regulated ROS signaling is primarily initiated by complexes I and III of the electron transport chain (ETC). Subsequent ROS production triggers the activation of nicotinamide adenine dinucleotide phosphate oxidase 2 (NADPH oxidase 2), prolonging the oxidative signal. This signal then engages kinase signaling cascades such as the mitogen-activated protein kinase (MAPK) pathway and increases the activity of REDOX-sensitive transcription factors such as nuclear factor-kappa B (NF-κB) and activator protein-1 (AP-1). To limit ROS overproduction and prevent oxidative stress, nuclear factor erythroid 2-related factor 2 (Nrf2) and antioxidant proteins such as superoxide dismutases (SODs) finely regulate signal intensity and are capable of terminating the oxidative signal when needed. Thus, oxidative signals, such as T cell activation, are well-controlled and critical for cellular communication.
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Affiliation(s)
- Karsten Gülow
- Department of Internal Medicine I, Gastroenterology, Hepatology, Endocrinology, Rheumatology, Immunology, and Infectious Diseases, University Hospital Regensburg, 93053 Regensburg, Germany; (D.T.); (P.H.); (S.S.); (A.K.); (M.M.); (C.K.)
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Martins FM, Iglesias BA, Chaves OA, Gutknecht da Silva JL, Leal DBR, Back DF. Vanadium(V) complexes derived from triphenylphosphonium and hydrazides: cytotoxicity evaluation and interaction with biomolecules. Dalton Trans 2024; 53:8315-8327. [PMID: 38666341 DOI: 10.1039/d4dt00464g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/15/2024]
Abstract
The development of coordination compounds with antineoplastic therapeutic properties is currently focused on non-covalent interactions with deoxyribonucleic acid (DNA). Additionally, the interaction profiles of these compounds with globular plasma proteins, particularly serum albumin, warrant thorough evaluation. In this study, we report on the interactions between biomolecules and complexes featuring hydrazone-type imine ligands coordinated with vanadium. The potential to enhance the therapeutic efficiency of these compounds through mitochondrial targeting is explored. This targeting is facilitated by the derivatization of ligands with triphenylphosphonium groups. Thus, this work presents the synthesis, characterization, interactions, and cytotoxicity of dioxidovanadium(V) complexes (C1-C5) with a triphenylphosphonium moiety. These VV-species are coordinated to hydrazone-type iminic ligands derived from (3-formyl-4-hydroxybenzyl)triphenylphosphonium chloride ([AH]Cl) and aromatic hydrazides ([H2L1]Cl-[H2L5]Cl). The structures of the five complexes were elucidated through single-crystal X-ray diffraction and vibrational spectroscopies, confirming the presence of dioxidovanadium(V) species in various geometries with degrees of distortion (τ = 0.03-0.50) and highlighting their zwitterionic characteristics. The molecular structural stability of C1-C5 in solution was ascertained using 1H, 19F, 31P, and 51V-nuclear magnetic resonance. Moreover, their interactions with biomolecules were evaluated using diverse spectroscopic methodologies and molecular docking, indicating moderate interactions (Kb ≈ 104 M-1) with calf thymus DNA in the minor groove and with human serum albumin, predominantly in the superficial IB subdomain. Lastly, the cytotoxic potentials of these complexes were assessed in keratinocytes of the HaCaT lineage, revealing that C1-C5 induce a reduction in metabolic activity and cell viability through apoptotic pathways.
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Affiliation(s)
- Francisco Mainardi Martins
- Laboratory of Inorganic Materials, Department of Chemistry, CCNE, UFSM, Santa Maria, RS, 97105-900, Brazil.
| | - Bernardo Almeida Iglesias
- Laboratory of Bioinorganic and Porphyrin Materials, Department of Chemistry, CCNE, UFSM, Santa Maria, RS, 97105-900, Brazil
| | - Otávio Augusto Chaves
- CQC-IMS, Department of Chemistry, University of Coimbra, Rua Larga s/n, Coimbra, 3004-535, Portugal
- Laboratory of Immunopharmacology, Centro de Pesquisa, Inovação e Vigilância em COVID-19 e Emergências Sanitárias (CPIV), Oswaldo Cruz Institute (IOC), Oswaldo Cruz Foundation (Fiocruz), Rio de Janeiro, RJ, 21040-361, Brazil
| | | | | | - Davi Fernando Back
- Laboratory of Inorganic Materials, Department of Chemistry, CCNE, UFSM, Santa Maria, RS, 97105-900, Brazil.
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He X, Jarrell ZR, Liang Y, Ryan Smith M, Orr ML, Marts L, Go YM, Jones DP. Vanadium pentoxide induced oxidative stress and cellular senescence in human lung fibroblasts. Redox Biol 2022; 55:102409. [PMID: 35870339 PMCID: PMC9307685 DOI: 10.1016/j.redox.2022.102409] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Revised: 06/30/2022] [Accepted: 07/12/2022] [Indexed: 11/25/2022] Open
Abstract
Both environmental exposure to vanadium pentoxide (V2O5, V+5 for its ionic counterparts) and fibroblast senescence are associated with pulmonary fibrosis, but whether V+5 causes fibroblast senescence remains unknown. We found in a dose-response study that 2-40 μM V+5 caused human lung fibroblasts (HLF) senescence with increased senescence-associated β-galactosidase activity and p16 expression, while cell death occurred at higher concentration (LC50, 82 μM V+5). Notably, measures of reactive oxygen species (ROS) production with fluorescence probes showed no association of ROS with V+5-dependent senescence. Preloading catalase (polyethylene-conjugated), a H2O2 scavenger, did not alleviate the cellular senescence induced by V+5. Analyses of the cellular glutathione (GSH) system showed that V+5 oxidized GSH, increased GSH biosynthesis, stimulated cellular GSH efflux and increased protein S-glutathionylation, and addition of N-acetyl cysteine inhibited V+5-elevated p16 expression, suggesting that thiol oxidation mediates V+5-caused senescence. Moreover, strong correlations between GSSG/GSH redox potential (Eh), protein S-glutathionylation, and cellular senescence (R2 > 0.99, p < 0.05) were present in V+5-treated cells. Studies with cell-free and enzyme-free solutions showed that V+5 directly oxidized GSH with formation of V+4 and GSSG in the absence of O2. Analyses of V+5 and V+4 in HLF and culture media showed that V+5 was reduced to V+4 in cells and that a stable V+4/V+5 ratio was rapidly achieved in extracellular media, indicating ongoing release of V+4 and reoxidation to V+5. Together, the results show that V+5-dependent fibroblast senescence is associated with a cellular/extracellular redox cycling mechanism involving the GSH system and occurring under conditions that do not cause cell death. These results establish a mechanism by which environmental vanadium from food, dietary supplements or drinking water, can cause or contribute to lung fibrosis in the absence of high-level occupational exposures and cytotoxic cell death.
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Affiliation(s)
- Xiaojia He
- Division of Pulmonary, Allergy and Critical Care Medicine, Emory University, Atlanta, GA, 30322, USA
| | - Zachery R Jarrell
- Division of Pulmonary, Allergy and Critical Care Medicine, Emory University, Atlanta, GA, 30322, USA
| | - Yongliang Liang
- Division of Pulmonary, Allergy and Critical Care Medicine, Emory University, Atlanta, GA, 30322, USA
| | - Matthew Ryan Smith
- Division of Pulmonary, Allergy and Critical Care Medicine, Emory University, Atlanta, GA, 30322, USA
| | - Michael L Orr
- Division of Pulmonary, Allergy and Critical Care Medicine, Emory University, Atlanta, GA, 30322, USA
| | - Lucian Marts
- Division of Pulmonary, Allergy and Critical Care Medicine, Emory University, Atlanta, GA, 30322, USA
| | - Young-Mi Go
- Division of Pulmonary, Allergy and Critical Care Medicine, Emory University, Atlanta, GA, 30322, USA.
| | - Dean P Jones
- Division of Pulmonary, Allergy and Critical Care Medicine, Emory University, Atlanta, GA, 30322, USA.
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Basova LV, Vien W, Bortell N, Najera JA, Marcondes MCG. Methamphetamine signals transcription of IL1β and TNFα in a reactive oxygen species-dependent manner and interacts with HIV-1 Tat to decrease antioxidant defense mechanisms. Front Cell Neurosci 2022; 16:911060. [PMID: 36060276 PMCID: PMC9434488 DOI: 10.3389/fncel.2022.911060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Accepted: 07/19/2022] [Indexed: 11/13/2022] Open
Abstract
Methamphetamine (Meth) abuse is a common HIV co-morbidity that is linked to aggravated Central Nervous System (CNS) inflammation, which accentuates HIV- associated neurological disorders, triggered both directly or indirectly by the drug. We used the well-established human innate immune macrophage cell line system (THP1) to demonstrate that Reactive Oxygen Species (ROS) immediately induced by Meth play a role in the increased transcription of inflammatory genes, in interaction with HIV-1 Tat peptide. Meth and Tat, alone and together, affect early events of transcriptional activity, as indicated by changes in RNA polymerase (RNAPol) recruitment patterns throughout the genome, via ROS-dependent and -independent mechanisms. IL1β (IL1β) and TNF α (TNFα), two genes with defining roles in the inflammatory response, were both activated in a ROS-dependent manner. We found that this effect occurred via the activation of the activator protein 1 (AP-1) comprising cFOS and cJUN transcription factors and regulated by the SRC kinase. HIV-1 Tat, which was also able to induce the production of ROS, did not further impact the effects of ROS in the context of Meth, but promoted gene activity independently from ROS, via additional transcription factors. For instance, HIV-1 Tat increased NFkB activation and activated gene clusters regulated by Tata box binding peptide, ING4 and IRF2. Importantly, HIV-1 Tat decreased the expression of anti-oxidant genes, where its suppression of the detoxifying machinery may contribute to the aggravation of oxidative stress induced by ROS in the context of Meth. Our results provide evidence of effects of Meth via ROS and interactions with HIV Tat that promote the transcription of inflammatory genes such as IL1β and TNFα.
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Affiliation(s)
- Liana V. Basova
- San Diego Biomedical Research Institute, San Diego, CA, United States
- The Scripps Research Institute, La Jolla, CA, United States
| | - Whitney Vien
- The Scripps Research Institute, La Jolla, CA, United States
- University of California San Diego, La Jolla, CA, United States
| | - Nikki Bortell
- The Scripps Research Institute, La Jolla, CA, United States
| | | | - Maria Cecilia Garibaldi Marcondes
- San Diego Biomedical Research Institute, San Diego, CA, United States
- The Scripps Research Institute, La Jolla, CA, United States
- *Correspondence: Maria Cecilia Garibaldi Marcondes,
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Liu H, Liu Z, Zhang Y, Chen Y, Wang H, Tan H, Zhang W. Antioxidant Aryl-Substituted Phthalan Derivatives Produced by Endophytic Fungus Cytospora rhizophorae. Front Chem 2022; 10:826615. [PMID: 35237559 PMCID: PMC8882737 DOI: 10.3389/fchem.2022.826615] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Accepted: 01/24/2022] [Indexed: 11/14/2022] Open
Abstract
Six new phthalan derivatives cytorhizophins D-I (1-6) as well as three known derivatives cytorhizophin C, pestacin and rhizophol B were isolated from Cytospora rhizophorae. Among them, cytorhizophins D-E (1-2) and F-G (3-4) were two pairs of diastereoisomers, all of them featuring a 1-phenyl-1,3-dihydroisobenzofuran scaffold with a highly oxygenated O-linked isopentenyl unit. Besides, cytorhizophins H-I (5-6) represent the first examples of phthalide family with fascinating 6/6/6/5 tetracyclic ring system fusing as unprecedented furo [4,3,2-kl]xanthen-2 (10bH)-one skeleton. The structures of the new phthalan derivatives were extensively confirmed by detail spectroscopic analysis. The partial absolute configurations of compounds 1-6 were established through electronic circular dichroism (ECD) calculations. Moreover, compounds 1-4 showed remarkable antioxidant activities with EC50 values ranging from 5.86 to 26.80 μM, which were better than or comparable to that of ascorbic acid (positive control).
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Affiliation(s)
- Hongxin Liu
- State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Open Laboratory of Applied Microbiology, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou, China
| | - Zhaoming Liu
- State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Open Laboratory of Applied Microbiology, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou, China
| | - Yanjiang Zhang
- National Engineering Research Center of Navel Orange, Gannan Normal University, Ganzhou, China
| | - Yuchan Chen
- State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Open Laboratory of Applied Microbiology, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou, China
| | - Huan Wang
- National Engineering Research Center of Navel Orange, Gannan Normal University, Ganzhou, China
- Key Laboratory of South China Agricultural Plant Molecular Analysis and Genetic Improvement, Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China
| | - Haibo Tan
- National Engineering Research Center of Navel Orange, Gannan Normal University, Ganzhou, China
- Key Laboratory of South China Agricultural Plant Molecular Analysis and Genetic Improvement, Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China
- *Correspondence: Haibo Tan, ; Weimin Zhang,
| | - Weimin Zhang
- State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Open Laboratory of Applied Microbiology, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou, China
- *Correspondence: Haibo Tan, ; Weimin Zhang,
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Synthesis, structure, and cytotoxicity studies of oxidovanadium(IV and V) complexes bearing chelating phenolates. Polyhedron 2019. [DOI: 10.1016/j.poly.2019.06.051] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Lai CY, Dong QY, Chen JX, Zhu QS, Yang X, Chen WD, Zhao HP, Zhu L. Role of Extracellular Polymeric Substances in a Methane Based Membrane Biofilm Reactor Reducing Vanadate. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2018; 52:10680-10688. [PMID: 30106284 DOI: 10.1021/acs.est.8b02374] [Citation(s) in RCA: 86] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
For the first time, we demonstrated vanadate (V(V)) reduction in a membrane biofilm reactor (MBfR) using CH4 as the sole electron donor. The V(V)-reducing capability of the biofilm kept increasing, with complete removal of V(V) achieved when the influent surface loading of V(V) was 363 mg m-2 day-1. Almost all V(V) was reduced to V(IV) precipitates, which is confirmed by a scanning electron microscope coupled to energy dispersive X-ray spectroscopy (SEM-EDS) and X-ray photoelectron spectroscopy (XPS). Microbial community analysis revealed that denitrifiers Methylomonas and Denitratisoma might be the main genera responsible for V(V) reduction. The constant enrichment of Methylophilus suggests that the intermediate (i.e., methanol) from CH4 metabolism might be used as the electron carriers for V(V) bioreduction. Intrusion of V(V) (2-5 mg/L, at the surface loading of 150-378 mg m-2 day-1) into the biofilm stimulated the secretion of extracellular polymeric substances (EPS), but high loading of V(V) (10 mg/L, at the surface loading of 668 mg m-2 day-1) decreased the amount of EPS. Metagenomic prediction analysis established the strong correlation between the secretion of EPS and the microbial metabolism associated with V(V) reduction, tricarboxylic acid cycle (TCA) cycle, methane oxidation, and ATP production, and EPS might relieve the oxidative stress induced by high loading of V(V). Colorimetric determination and a three-dimensional excitation-emission matrix (3D-EEM) showed that tryptophan and humic acid-like substances might play important roles in microbial cell protection and V(V) binding. Fourier transform infrared (FTIR) spectroscopy identified hydroxyl (-OH) and carboxyl (COO-) groups in EPS as the candidate functional groups for binding V(V).
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Affiliation(s)
- Chun-Yu Lai
- College of Environmental and Resource Sciences , Zhejiang University , Hangzhou , China 310058
- Advanced Water Management Centre , The University of Queensland , St. Lucia , Queensland 4072 , Australia
| | - Qiu-Yi Dong
- College of Environmental and Resource Sciences , Zhejiang University , Hangzhou , China 310058
| | - Jia-Xian Chen
- College of Environmental and Resource Sciences , Zhejiang University , Hangzhou , China 310058
| | - Quan-Song Zhu
- College of Environmental and Resource Sciences , Zhejiang University , Hangzhou , China 310058
| | - Xin Yang
- College of Environmental and Resource Sciences , Zhejiang University , Hangzhou , China 310058
| | - Wen-Da Chen
- College of Environmental and Resource Sciences , Zhejiang University , Hangzhou , China 310058
| | - He-Ping Zhao
- College of Environmental and Resource Sciences , Zhejiang University , Hangzhou , China 310058
- Zhejiang Province Key Laboratory for Water Pollution Control and Environmental Safety , Zhejiang University , Hangzhou , Zhejiang , China 310058
- MOE Key Laboratory of Environmental Remediation and Ecosystem Health, College of Environmental and Resource Sciences , Zhejiang University , Hangzhou , China 310058
| | - Liang Zhu
- College of Environmental and Resource Sciences , Zhejiang University , Hangzhou , China 310058
- Zhejiang Province Key Laboratory for Water Pollution Control and Environmental Safety , Zhejiang University , Hangzhou , Zhejiang , China 310058
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Fernández I, Gavaia PJ, Laizé V, Cancela ML. Fish as a model to assess chemical toxicity in bone. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2018; 194:208-226. [PMID: 29202272 DOI: 10.1016/j.aquatox.2017.11.015] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2017] [Revised: 11/14/2017] [Accepted: 11/22/2017] [Indexed: 06/07/2023]
Abstract
Environmental toxicology has been expanding as growing concerns on the impact of produced and released chemical compounds over the environment and human health are being demonstrated. Among the toxic effects observed in organisms exposed to pollutants, those affecting skeletal tissues (osteotoxicity) have been somehow overlooked in comparison to hepato-, immune-, neuro- and/or reproductive toxicities. Nevertheless, sub-lethal effects of toxicants on skeletal development and/or bone maintenance may result in impaired growth, reduced survival rate, increased disease susceptibility and diminished welfare. Osteotoxicity may occur by acute or chronic exposure to different environmental insults. Because of biologically and technically advantagous features - easy to breed and inexpensive to maintain, external and rapid rate of development, translucent larvae and the availability of molecular and genetic tools - the zebrafish (Danio rerio) has emerged in the last decade as a vertebrate model system of choice to evaluate osteotoxicity. Different experimental approaches in fish species and analytical tools have been applied, from in vitro to in vivo systems, from specific to high throughput methodologies. Current knowledge on osteotoxicity and underlying mechanisms gained using fish, with a special emphasis on zebrafish systems, is reviewed here. Osteotoxicants have been classified into four categories according to the pathway involved in the transduction of the osteotoxic effects: activation/inhibition of membrane and/or nuclear receptors, alteration of redox condition, mimicking of bone constituents and unknown pathways. Knowledge on these pathways is also reported here as it may provide critical insights into the development, production and release of future chemical compounds with none or low osteotoxicity, thus promoting the green/environmental friendly chemistry.
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Affiliation(s)
- Ignacio Fernández
- Centre of Marine Sciences (CCMAR), University of Algarve, Campus de Gambelas, Faro, Portugal.
| | - Paulo J Gavaia
- Centre of Marine Sciences (CCMAR), University of Algarve, Campus de Gambelas, Faro, Portugal; Department of Biomedical Sciences and Medicine, University of Algarve, Campus de Gambelas, Faro, Portugal
| | - Vincent Laizé
- Centre of Marine Sciences (CCMAR), University of Algarve, Campus de Gambelas, Faro, Portugal
| | - M Leonor Cancela
- Centre of Marine Sciences (CCMAR), University of Algarve, Campus de Gambelas, Faro, Portugal; Department of Biomedical Sciences and Medicine, University of Algarve, Campus de Gambelas, Faro, Portugal; Algarve Biomedical Center (ABC), Universidade do Algarve, Campus de Gambelas, Faro, Portugal
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Capala ME, Pruis M, Vellenga E, Schuringa JJ. Depletion of SAM50 Specifically Targets BCR-ABL-Expressing Leukemic Stem and Progenitor Cells by Interfering with Mitochondrial Functions. Stem Cells Dev 2016; 25:427-37. [PMID: 26855047 DOI: 10.1089/scd.2015.0151] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
A high proliferation rate of malignant cells requires an increased energy production, both by anaerobic glucose metabolism and mitochondrial respiration. Moreover, increased levels of mitochondria-produced reactive oxygen species (ROS) promote survival of transformed cells and contribute to the disease progression both in solid tumors and leukemia. Consequently, interfering with mitochondrial metabolism has been used as a strategy to specifically target leukemic cells. SAM50 is a mitochondrial outer membrane protein involved in the formation of mitochondrial intermembrane space bridging (MIB) complex. Although the importance of SAM50 in maintaining MIB integrity and in the assembly of mitochondrial respiratory chain complexes has been described, its specific role in the normal and leukemic hematopoietic cells remains unknown. We observed that human leukemic cells display a specific dependency on SAM50 expression, as downregulation of SAM50 in BCR-ABL-expressing, but not normal CD34(+) human hematopoietic stem and progenitor cells (HSPCs) caused a significant decrease in growth, colony formation, and replating capacity. Mitochondrial functions of BCR-ABL-expressing HSPCs were compromised, as seen by a decreased mitochondrial membrane potential and respiration. This effect of SAM50 downregulation was recapitulated in normal HSPCs exposed to cytokine-rich culture conditions that stimulate proliferation. Both oncogene-transduced and cytokine-stimulated HSPCs showed increased mitochondrial membrane potential and increased ROS levels compared to their normal counterparts. Therefore, we postulate that human leukemic HSPCs are highly dependent on the proper functioning of mitochondria and that disruption of mitochondrial integrity may aid in targeting leukemic cells.
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Affiliation(s)
- Marta E Capala
- Department of Experimental Hematology, Cancer Research Center Groningen (CRCG), University Medical Center Groningen, University of Groningen , Groningen, The Netherlands
| | - Maurien Pruis
- Department of Experimental Hematology, Cancer Research Center Groningen (CRCG), University Medical Center Groningen, University of Groningen , Groningen, The Netherlands
| | - Edo Vellenga
- Department of Experimental Hematology, Cancer Research Center Groningen (CRCG), University Medical Center Groningen, University of Groningen , Groningen, The Netherlands
| | - Jan Jacob Schuringa
- Department of Experimental Hematology, Cancer Research Center Groningen (CRCG), University Medical Center Groningen, University of Groningen , Groningen, The Netherlands
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Banda M, McKim KL, Haber LT, MacGregor JA, Gollapudi BB, Parsons BL. Quantification of Kras mutant fraction in the lung DNA of mice exposed to aerosolized particulate vanadium pentoxide by inhalation. MUTATION RESEARCH-GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2015; 789-790:53-60. [DOI: 10.1016/j.mrgentox.2015.07.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2015] [Revised: 07/01/2015] [Accepted: 07/02/2015] [Indexed: 01/11/2023]
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Pituitary Adenylate Cyclase-Activating Polypeptide Reverses Ammonium Metavanadate-Induced Airway Hyperresponsiveness in Rats. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2015. [PMID: 26199679 PMCID: PMC4496651 DOI: 10.1155/2015/787561] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The rate of atmospheric vanadium is constantly increasing due to fossil fuel combustion. This environmental pollution favours vanadium exposure in particular to its vanadate form, causing occupational bronchial asthma and bronchitis. Based on the well admitted bronchodilator properties of the pituitary adenylate cyclase-activating polypeptide (PACAP), we investigated the ability of this neuropeptide to reverse the vanadate-induced airway hyperresponsiveness in rats. Exposure to ammonium metavanadate aerosols (5 mg/m3/h) for 15 minutes induced 4 hours later an array of pathophysiological events, including increase of bronchial resistance and histological alterations, activation of proinflammatory alveolar macrophages, and increased oxidative stress status. Powerfully, PACAP inhalation (0.1 mM) for 10 minutes alleviated many of these deleterious effects as demonstrated by a decrease of bronchial resistance and histological restoration. PACAP reduced the level of expression of mRNA encoding inflammatory chemokines (MIP-1α, MIP-2, and KC) and cytokines (IL-1α and TNF-α) in alveolar macrophages and improved the antioxidant status. PACAP reverses the vanadate-induced airway hyperresponsiveness not only through its bronchodilator activity but also by counteracting the proinflammatory and prooxidative effects of the metal. Then, the development of stable analogs of PACAP could represent a promising therapeutic alternative for the treatment of inflammatory respiratory disorders.
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Korbecki J, Baranowska-Bosiacka I, Gutowska I, Chlubek D. Vanadium Compounds as Pro-Inflammatory Agents: Effects on Cyclooxygenases. Int J Mol Sci 2015; 16:12648-68. [PMID: 26053397 PMCID: PMC4490466 DOI: 10.3390/ijms160612648] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2015] [Revised: 05/12/2015] [Accepted: 05/19/2015] [Indexed: 01/30/2023] Open
Abstract
This paper discusses how the activity and expression of cyclooxygenases are influenced by vanadium compounds at anticancer concentrations and recorded in inorganic vanadium poisonings. We refer mainly to the effects of vanadate (orthovanadate), vanadyl and pervanadate ions; the main focus is placed on their impact on intracellular signaling. We describe the exact mechanism of the effect of vanadium compounds on protein tyrosine phosphatases (PTP), epidermal growth factor receptor (EGFR), PLCγ, Src, mitogen-activated protein kinase (MAPK) cascades, transcription factor NF-κB, the effect on the proteolysis of COX-2 and the activity of cPLA2. For a better understanding of these processes, a lot of space is devoted to the transformation of vanadium compounds within the cell and the molecular influence on the direct targets of the discussed vanadium compounds.
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Affiliation(s)
- Jan Korbecki
- Department of Biochemistry and Medical Chemistry, Pomeranian Medical University, Powstańców Wlkp. 72 Av., 70-111 Szczecin, Poland.
| | - Irena Baranowska-Bosiacka
- Department of Biochemistry and Medical Chemistry, Pomeranian Medical University, Powstańców Wlkp. 72 Av., 70-111 Szczecin, Poland.
| | - Izabela Gutowska
- Department of Biochemistry and Human Nutrition, Pomeranian Medical University, Broniewskiego 24 Str., 71-460 Szczecin, Poland.
| | - Dariusz Chlubek
- Department of Biochemistry and Medical Chemistry, Pomeranian Medical University, Powstańców Wlkp. 72 Av., 70-111 Szczecin, Poland.
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Kim T, Lawson MA. GnRH Regulates Gonadotropin Gene Expression Through NADPH/Dual Oxidase-Derived Reactive Oxygen Species. Endocrinology 2015; 156:2185-99. [PMID: 25849727 PMCID: PMC4430611 DOI: 10.1210/en.2014-1709] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The appropriate control of synthesis and secretion of the gonadotropin hormones LH and FSH by pituitary gonadotropes is essential for the regulation of reproduction. The hypothalamic neuropeptide GnRH is the central regulator of both processes, coordinating secretion with transcription and translation of the gonadotropin hormone subunit genes. The MAPK family of second messengers is strongly induced in gonadotropes upon GnRH stimulation, and multiple pathways activate these kinases. Intracellular reactive oxygen species participate in signaling cascades that target MAPKs, but also participate in signaling events indicative of cell stress. The NADPH oxidase (NOX)/dual oxidase (DUOX) family is a major enzymatic source of intracellular reactive oxygen, and we show that GnRH stimulation of mouse primary pituitary cells and the LβT2 gonadotrope cell line elevates intracellular reactive oxygen via NOX/DUOX activity. Mouse pituitary and LβT2 cells abundantly express NOX/DUOX and cofactor mRNAs. Pharmacological inhibition of NOX/DUOX activity diminishes GnRH-stimulated activation of MAPKs, immediate-early gene expression, and gonadotropin subunit gene expression. Inhibitor studies implicate the calcium-activated DUOX family as a major, but not exclusive, participant in GnRH signaling. Knockdown of DUOX2 in LβT2 cells reduces GnRH-induced Fshb, but not Lhb mRNA levels, suggesting differential sensitivity to DUOX activity. Finally, GnRH pulse-stimulated FSH and LH secretion are suppressed by inhibition of NOX/DUOX activity. These results indicate that reactive oxygen is a potent signaling intermediate produced in response to GnRH stimulation and further suggest that reactive oxygen derived from other sources may influence the gonadotrope response to GnRH stimulation.
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Affiliation(s)
- Taeshin Kim
- Department of Reproductive Medicine, University of California, San Diego, La Jolla, California 92093
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15
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Iron diminishes the in vitro biological effect of vanadium. J Inorg Biochem 2015; 147:126-33. [DOI: 10.1016/j.jinorgbio.2015.03.008] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2014] [Revised: 03/16/2015] [Accepted: 03/16/2015] [Indexed: 01/02/2023]
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Korbecki J, Baranowska-Bosiacka I, Gutowska I, Piotrowska K, Chlubek D. Cyclooxygenase-1 as the main source of proinflammatory factors after sodium orthovanadate treatment. Biol Trace Elem Res 2015; 163:103-11. [PMID: 25398544 PMCID: PMC4297299 DOI: 10.1007/s12011-014-0176-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/22/2014] [Accepted: 11/04/2014] [Indexed: 11/03/2022]
Abstract
Vanadium is a metal present in air pollution. Its compounds may have both anticancer and carcinogenic properties. Vanadium compounds are tested in treatment of diabetes and cancer. An important research direction aimed at better understanding of the mechanisms of action of the vanadium compounds is a more detailed insight into their impact on inflammatory reactions. The aim of this study was to examine the effect of micromolar concentrations of sodium orthovanadate, Na3VO4, on the activity and expression of cyclooxygenases: COX-1 and COX-2. PMA-activated THP-1 macrophages were incubated in vitro for 48 h with micromolar concentrations of sodium orthovanadate. As shown by an ELISA assay, sodium orthovanadate increases the quantity of prostaglandin E2 being released into the medium in a dose-dependent manner as well as impacts the quantity of the stable metabolite of thromboxane A2: thromboxane B2. The use of a COX-2 inhibitor, NS-398, revealed that this effect was independent of changes in the activity of COX-2. Western blotting analysis showed that sodium orthovanadate increased the expression of COX-2 when used with NS-398. Quantitative real-time PCR measurements of mRNA levels of genes PTGS1 and PTGS2 revealed no effect of the tested vanadium compound on the levels of analyzed transcripts.
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Affiliation(s)
- Jan Korbecki
- Department of Biochemistry and Medical Chemistry, Pomeranian Medical University, Powstańców Wlkp. 72 Av., 70-111, Szczecin, Poland,
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Maurya R, Sutradhar D, Martin M, Roy S, Chourasia J, Sharma A, Vishwakarma P. Oxovanadium(IV) complexes of medicinal relevance: Synthesis, characterization, and 3D-molecular modeling and analysis of some oxovanadium(IV) complexes in O,N-donor coordination matrix of sulfa drug Schiff bases derived from a 2-pyrazolin-5-one derivative. ARAB J CHEM 2015. [DOI: 10.1016/j.arabjc.2011.01.009] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
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18
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Wang H, Wang T, You L, Zhong G, Shi G. Effects of vanadate supply on plant growth, Cu accumulation, and antioxidant capacities in Triticum aestivum L. ENVIRONMENTAL GEOCHEMISTRY AND HEALTH 2013; 35:585-592. [PMID: 23824494 DOI: 10.1007/s10653-013-9541-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2012] [Accepted: 04/15/2013] [Indexed: 06/02/2023]
Abstract
The effects of normal vanadate (V) supply (40 μM) on copper (Cu) accumulation, plant growth and reduction in Cu toxicity in wheat seedlings (Triticum aestivum L.) were investigated. The results showed Cu accumulation (mg g(-1 )dw) in the applied V treatment was about 10.2 % in shoots and 16.7 % in roots higher up on exposure to excess Cu (300 μM) than that observed only in excess Cu plants. Compared with the treatment of the normal concentration used in Hoagland's culture solution Cu (0.6 μM), excess Cu significantly induced lipid peroxidation indicated by accumulation of thiobarbituric acid reactive substances (MDA). The seedlings showed apparent symptoms of Cu toxicity and plant growth were significantly inhibited by excess Cu. The applied V significantly decreased lipid peroxidation in roots caused by excess Cu and inhibited the appearance of Cu toxicity symptoms. Moreover, the applied V effectively improved the antioxidant defense system to alleviate the oxidative damage induced by Cu. Although the addition of V could promote superoxide dismutase in both shoots and roots to reduce superoxide radicals, peroxidase and catalase in shoots and ascorbate peroxidase and dehydroascorbate reductase in roots were major enzymes to eliminate H2O2 in wheat seedlings.
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Affiliation(s)
- Haiou Wang
- Department of Biological Science and Engineering, School of Chemical and Biological Engineering, University of Science and Technology Beijing, Beijing, China.
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Deng Y, Cui H, Peng X, Fang J, Zuo Z, Wang K, Cui W, Wu B. Changes of IgA+ cells and cytokines in the cecal tonsil of broilers fed on diets supplemented with vanadium. Biol Trace Elem Res 2012; 147:149-55. [PMID: 22270623 DOI: 10.1007/s12011-012-9330-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/04/2011] [Accepted: 01/10/2012] [Indexed: 11/25/2022]
Abstract
The cecal tonsil of broiler is known as a secondary lymphoid tissue, which is involved in antigen-specific humoral immune responses. The purpose of this study was to investigate the effects of dietary vanadium on the tissue distribution and quantity of immunoglobulin A-positive (IgA(+)) cell in the cecal tonsil by immunohistochemistry. Simultaneously, the changes in interleukin-6 (IL-6), interleukin-10 (IL-10), interferon gamma (IFN-γ) and tumor necrosis factor-alpha (TNF-α) contents in the cecal tonsil were also quantified by enzyme-linked immunosorbent assay (ELISA). A total of 420 one-day-old avian broilers were divided into six groups and fed on a corn-soybean basal diet (control diet) or the same diet supplemented respectively with 5, 15, 30, 45, and 60 mg/kg of vanadium in the form of ammonium metavanadate for 42 days. The results showed that the population of the IgA(+) cells in the cecal tonsil were significantly lower (p < 0.05 or p < 0.01) in the 45 and 60 mg/kg groups than that in the control group. Meanwhile, IL-10, IFN-γ and TNF-α contents in the cecal tonsil were significantly decreased (p < 0.05 or p < 0.01) in the 30, 45 and 60 mg/kg groups in comparison with those of the control group. However, IL-6 content in the cecal tonsil was only decreased (p < 0.05 or p < 0.01) in 60 mg/kg at 14 and 28 days of age. In conclusion, dietary vanadium in excess of 30 mg/kg reduced the numbers of the IgA(+) cells and changed the contents of the abovementioned cytokines in the cecal tonsil, which may finally impact the function of local mucosal humoral immunity in broilers.
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Affiliation(s)
- Yuanxin Deng
- Key Laboratory of Animal Diseases and Environmental Hazards of Sichuan Province, College of Veterinary Medicine, Sichuan Agricultural University, Ya'an, China
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Kanno T, Nakamura K, Ikai H, Kikuchi K, Sasaki K, Niwano Y. Literature review of the role of hydroxyl radicals in chemically-induced mutagenicity and carcinogenicity for the risk assessment of a disinfection system utilizing photolysis of hydrogen peroxide. J Clin Biochem Nutr 2012; 51:9-14. [PMID: 22798706 PMCID: PMC3391867 DOI: 10.3164/jcbn.11-105] [Citation(s) in RCA: 207] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2011] [Accepted: 09/26/2011] [Indexed: 11/22/2022] Open
Abstract
We have developed a new disinfection system for oral hygiene, proving that hydroxyl radicals generated by the photolysis of 1 M hydrogen peroxide could effectively kill oral pathogenic microorganisms. Prior to any clinical testing, the safety of the system especially in terms of the risk of carcinogenicity is examined by reviewing the literature. Previous studies have investigated indirectly the kinds of reactive oxygen species involved in some sort of chemically-induced mutagenicity in vitro by using reactive oxygen species scavengers, suggesting the possible involvement of hydroxyl radicals. Similarly, possible involvement of hydroxyl radicals in some sort of chemically-induced carcinogenicity has been proposed. Notably, it is suggested that the hydroxyl radical can play a role in heavy metal-induced carcinogenicity that requires chronic exposure to the carcinogen. In these cases, hydroxyl radicals produced by Fenton-like reactions may be involved in the carcinogenicity. Meanwhile, potential advantages have been reported on the use of the hydroxyl radical, being included in host immune defense by polymorphonuclear leukocytes, and medical applications such as for cancer treatment and antibiotics. From these, we conclude that there would seem to be little to no risk in using the hydroxyl radical as a disinfectant for short-term treatment of the oral cavity.
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Affiliation(s)
- Taro Kanno
- Tohoku University Graduate School of Dentistry, Seiryo-machi 4-1, Aoba-ku, Sendai 980-8575, Japan
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Rondini EA, Walters DM, Bauer AK. Vanadium pentoxide induces pulmonary inflammation and tumor promotion in a strain-dependent manner. Part Fibre Toxicol 2010; 7:9. [PMID: 20385015 PMCID: PMC2861012 DOI: 10.1186/1743-8977-7-9] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2009] [Accepted: 04/12/2010] [Indexed: 11/10/2022] Open
Abstract
Background Elevated levels of air pollution are associated with increased risk of lung cancer. Particulate matter (PM) contains transition metals that may potentiate neoplastic development through the induction of oxidative stress and inflammation, a lung cancer risk factor. Vanadium pentoxide (V2O5) is a component of PM derived from fuel combustion as well as a source of occupational exposure in humans. In the current investigation we examined the influence of genetic background on susceptibility to V2O5-induced inflammation and evaluated whether V2O5 functions as a tumor promoter using a 2-stage (initiation-promotion) model of pulmonary neoplasia in mice. Results A/J, BALB/cJ (BALB), and C57BL/6J (B6) mice were treated either with the initiator 3-methylcholanthrene (MCA; 10 μg/g; i.p.) or corn oil followed by 5 weekly aspirations of V2O5 or PBS and pulmonary tumors were enumerated 20 weeks following MCA treatment. Susceptibility to V2O5-induced pulmonary inflammation was assessed in bronchoalveolar lavage fluid (BALF), and chemokines, transcription factor activity, and MAPK signaling were quantified in lung homogenates. We found that treatment of animals with MCA followed by V2O5 promoted lung tumors in both A/J (10.3 ± 0.9 tumors/mouse) and BALB (2.2 ± 0.36) mice significantly above that observed with MCA/PBS or V2O5 alone (P < 0.05). No tumors were observed in the B6 mice in any of the experimental groups. Mice sensitive to tumor promotion by V2O5 were also found to be more susceptible to V2O5-induced pulmonary inflammation and hyperpermeability (A/J>BALB>B6). Differential strain responses in inflammation were positively associated with elevated levels of the chemokines KC and MCP-1, higher NFκB and c-Fos binding activity, as well as sustained ERK1/2 activation in lung tissue. Conclusions In this study we demonstrate that V2O5, an occupational and environmentally relevant metal oxide, functions as an in vivo lung tumor promoter among different inbred strains of mice. Further, we identified a positive relationship between tumor promotion and susceptibility to V2O5-induced pulmonary inflammation. These findings suggest that repeated exposures to V2O5 containing particles may augment lung carcinogenesis in susceptible individuals through oxidative stress mediated pathways.
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Affiliation(s)
- Elizabeth A Rondini
- Department of Pathobiology and Diagnostic Investigation and Center for Integrative Toxicology, Michigan State University, East Lansing, MI, 48824, USA
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Qin G, Meng Z. Sulfur dioxide and benzo(a)pyrene modulates CYP1A and tumor-related gene expression in rat liver. ENVIRONMENTAL TOXICOLOGY 2010; 25:169-179. [PMID: 19408242 DOI: 10.1002/tox.20484] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Sulfur dioxide (SO(2)) and benzo(a)pyrene (B(a)P) are common industrial and environmental contaminants. However, few data are available on the effects of SO(2) on proto-oncogenes and tumor suppressor genes, as well as the interactions between SO(2) and other xenobiotics regulating proto-oncogenes or tumor suppressor genes expression. To investigate the interactions between SO(2) and B(a)P, male Wistar rats were exposed to intratracheally instilled with B(a)P or SO(2) inhalation alone or together. We detected mRNA expression of CYP1A1 and 1A2, 7-ethoxyresorufin O-deethylase (EROD), and methoxyresorufin O-demethylase (MROD) activities in livers. The mRNA and protein levels of several cancer-related genes were analyzed in livers by real-time RT-PCR and Western blot, respectively. The EROD/MROD activities and CYP1A1/2 expression were down-regulated by SO(2) but up-regulated by B(a)P alone. Exposure of SO(2) alone induced c-fos, c-jun, c-myc, H-ras, and p53 expression, and depressed p16 and Rb expression in livers. The effects of B(a)P on the above gene were similar to SO(2) except c-fos expression. Furthermore, SO(2) + B(a)P exposure increased the expression of c-fos, c-jun, c-myc, and p53, and decreased p16 and Rb expression in livers compared with exposed to SO(2) or B(a)P alone. However, no synergistic effects were observed on H-ras and CYP1A1/2 after SO(2) + B(a)P exposure. Our findings indicate that multiple cell cycle regulatory proteins play key roles in the toxicity of SO(2) and B(a)P in livers. It might involve the activation of c-fos, c-jun, c-myc, and p53. And p16-Rb pathway might also participate in the progress. Although the gene products we studied are classed as oncogenes and tumor suppressor genes, their functions actually relate to more general processes of control of cell proliferation, survival, and/or apoptosis.
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Affiliation(s)
- Guohua Qin
- Institute of Environmental Medicine and Toxicology, Research Center of Environmental Science and Engineering, Shanxi University, Taiyuan 030006, China
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Samet JM, Tal TL. Toxicological disruption of signaling homeostasis: tyrosine phosphatases as targets. Annu Rev Pharmacol Toxicol 2010; 50:215-35. [PMID: 20055703 DOI: 10.1146/annurev.pharmtox.010909.105841] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The protein tyrosine phosphatases (PTPs) consist of a diverse group of enzymes whose activity opposes that of the tyrosine kinases. As such, the PTPs have critical roles in maintaining signaling quiescence in resting cells and in restoring homeostasis by effecting signal termination. Interest in these enzymes has increased in recent years following the discovery that the activity of PTPs is modulated through redox mechanisms during signaling. The molecular features that enable redox regulation of PTPs during physiological signaling also render them highly susceptible to oxidative and electrophilic inactivation by a broad spectrum of structurally disparate xenobiotic compounds. The loss of PTP activity results in a profound disregulation of protein phosphotyrosine metabolism, leading to widespread and persistent activation of signaling cascades in the cell.
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Affiliation(s)
- James M Samet
- U.S. Environmental Protection Agency, Chapel Hill, North Carolina, USA.
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Markopoulou S, Kontargiris E, Batsi C, Tzavaras T, Trougakos I, Boothman DA, Gonos ES, Kolettas E. Vanadium-induced apoptosis of HaCaT cells is mediated by c-fos and involves nuclear accumulation of clusterin. FEBS J 2009; 276:3784-99. [PMID: 19531052 DOI: 10.1111/j.1742-4658.2009.07093.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Vanadium exerts a variety of biological effects, including antiproliferative responses through activation of the respective signaling pathways and the generation of reactive oxygen species. As epidermal cells are exposed to environmental insults, human keratinocytes (HaCaT) were used to investigate the mechanism of the antiproliferative effects of vanadyl(IV) sulfate (VOSO(4)). Treatment of HaCaT cells with VOSO(4) inhibited proliferation and induced apoptosis in a dose-dependent manner. Inhibition of proliferation was associated with downregulation of cyclins D1 and E, E2F1, and the cyclin-dependent kinase inhibitors p21(Cip1/Waf1) and p27(Kip1). Induction of apoptosis correlated with upregulation of the c-fos oncoprotein, changes in the expression of clusterin (CLU), an altered ratio of antiapoptotic to proapoptotic Bcl-2 protein family members, and poly(ADP-ribose) polymerase-1 cleavage. Forced overexpression of c-fos induced apoptosis in HaCaT cells that correlated with secretory CLU downregulation and upregulation of nuclear CLU (nCLU), a pro-death protein. Overexpression of Bcl-2 protected HaCaT cells from vanadium-induced apoptosis, whereas secretory CLU overexpression offered no cytoprotection. In contrast, nCLU sensitized HaCaT cells to apoptosis. Our data suggest that vanadium-mediated apoptosis was promoted by c-fos, leading to alterations in CLU isoform processing and induction of the pro-death nCLU protein.
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Affiliation(s)
- Soultana Markopoulou
- Cellular and Molecular Physiology Unit, Laboratory of Physiology, School of Medicine, University of Ioannina, Greece
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Effects of sulfur dioxide derivatives on expression of oncogenes and tumor suppressor genes in human bronchial epithelial cells. Food Chem Toxicol 2009; 47:734-44. [DOI: 10.1016/j.fct.2009.01.005] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2008] [Revised: 12/11/2008] [Accepted: 01/04/2009] [Indexed: 12/30/2022]
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Li H, Xie P, Li G, Hao L, Xiong Q. In vivo study on the effects of microcystin extracts on the expression profiles of proto-oncogenes (c-fos, c-jun and c-myc) in liver, kidney and testis of male Wistar rats injected i.v. with toxins. Toxicon 2009; 53:169-75. [DOI: 10.1016/j.toxicon.2008.10.027] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2008] [Revised: 10/27/2008] [Accepted: 10/28/2008] [Indexed: 01/21/2023]
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Piñon-Zarate G, Rodriguez-Lara V, Rojas-Lemus M, Martinez-Pedraza M, Gonzalez-Villalva A, Mussali-Galante P, Fortoul TI, Barquet A, Masso F, Montaño LF. Vanadium Pentoxide Inhalation Provokes Germinal Center Hyperplasia and Suppressed Humoral Immune Responses. J Immunotoxicol 2008; 5:115-22. [DOI: 10.1080/15476910802085749] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
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28
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Mechanism of copper-activated transcription: activation of AP-1, and the JNK/SAPK and p38 signal transduction pathways. J Mol Biol 2008; 383:1008-18. [PMID: 18793645 DOI: 10.1016/j.jmb.2008.08.080] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2008] [Revised: 08/18/2008] [Accepted: 08/25/2008] [Indexed: 11/23/2022]
Abstract
Copper is an essential metal that is able to produce reactive oxygen species and to induce intracellular oxidative stress. Several studies have examined the effects of excessive copper and oxidative stress on various organisms and tissues, but few have addressed the molecular mechanisms by which copper affects transcription. Our results demonstrated that, in COS-7 cells, copper treatment caused an increase in the binding of nuclear proteins to activating protein-1 and antioxidant response elements. The level of copper-inducible nuclear protein binding was modulated by increasing or decreasing the level of intracellular oxidative stress. Copper exposure also led to an increase in the steady-state levels of c-fos, c-jun, and c-myc mRNAs. Exposure to copper resulted in an increase in the levels of phosphorylation and activation of the c-Jun N-terminal kinase/stress-activated protein kinase and p38 pathways. The activation of these pathways resulted in a concomitant increase in c-Jun phosphorylation. We investigated the hypothesis that copper-induced oxidative stress leads to the formation of stable lipid peroxidation by-products that activate mitogen-activated protein kinase (MAPK) pathways, ultimately affecting transcription. While exposure did result in the production of 4-hydroxynonenal, the timing of the increased levels of proto-oncogene mRNA, phosphorylation of c-jun, and phosphorylation and activation of MAPKs, as well as the inability of the lipophilic antioxidant vitamin E to abrogate MAPK phosphorylation, suggest that the formation of stable lipid peroxidation by-products may not be the primary mechanism by which copper activates MAPKs. These results further elucidate the effects of copper on signal transduction pathways to alter gene expression.
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Carcinogenic metal compounds: recent insight into molecular and cellular mechanisms. Arch Toxicol 2008; 82:493-512. [PMID: 18496671 DOI: 10.1007/s00204-008-0313-y] [Citation(s) in RCA: 661] [Impact Index Per Article: 41.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2008] [Accepted: 04/30/2008] [Indexed: 02/07/2023]
Abstract
Mechanisms of carcinogenicity are discussed for metals and their compounds, classified as carcinogenic to humans or considered to be carcinogenic to humans: arsenic, antimony, beryllium, cadmium, chromium, cobalt, lead, nickel and vanadium. Physicochemical properties govern uptake, intracellular distribution and binding of metal compounds. Interactions with proteins (e.g., with zinc finger structures) appear to be more relevant for metal carcinogenicity than binding to DNA. In general, metal genotoxicity is caused by indirect mechanisms. In spite of diverse physicochemical properties of metal compounds, three predominant mechanisms emerge: (1) interference with cellular redox regulation and induction of oxidative stress, which may cause oxidative DNA damage or trigger signaling cascades leading to stimulation of cell growth; (2) inhibition of major DNA repair systems resulting in genomic instability and accumulation of critical mutations; (3) deregulation of cell proliferation by induction of signaling pathways or inactivation of growth controls such as tumor suppressor genes. In addition, specific metal compounds exhibit unique mechanisms such as interruption of cell-cell adhesion by cadmium, direct DNA binding of trivalent chromium, and interaction of vanadate with phosphate binding sites of protein phosphatases.
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Fu Y, Wang Q, Yang XG, Yang XD, Wang K. Vanadyl bisacetylacetonate induced G1/S cell cycle arrest via high-intensity ERK phosphorylation in HepG2 cells. J Biol Inorg Chem 2008; 13:1001-9. [PMID: 18483753 DOI: 10.1007/s00775-008-0387-2] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2008] [Accepted: 04/30/2008] [Indexed: 12/22/2022]
Abstract
In recent years the anticancer properties of vanadium compounds have been noticed, but the underlying mechanisms are not well understood. In the present work, we found that vanadyl bisacetylacetonate ([VO(acac)(2)]) blocked cell cycle progression permanently at G1 phase in a dose- and time-dependent manner in HepG2 cells. This was further evidenced by the growth regulatory signals during the G1 stage. After the treatment with [VO(acac)(2)], the level of phosphorylation of retinoblastoma tumor suppressor protein (pRb) and the expressions of cyclin D1, cyclin E and cyclin A were reduced, while the expression of a cyclin-dependent kinase inhibitor p21 was increased dose-dependently. In the meantime, neither O(2)(*-) nor H(2)O(2) level was observed to increase. Interestingly, the levels of phosphorylated extracellular signal-regulated protein kinase (ERK) and Akt were highly activated. After 1-h pretreatment with a lower concentration of MEK inhibitor U0126, the level of phosphorylated pRb was restored, indicating a release of cell cycle arrest. Taken together, we suggested that [VO(acac)(2)]-induced proliferation inhibition was caused by G1/S cell cycle arrest, which resulted from the decreased level of phosphorylated pRb in its active hypophosphorylated form via a highly activated ERK signal in HepG2 cells. The results presented here provided new insight into the development of vanadium compounds as potential anticancer agents.
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Affiliation(s)
- Ying Fu
- Department of Chemical Biology, School of Pharmaceutical Sciences, Peking University Health Science Center, Beijing 100083, People's Republic of China
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Internal tandem duplication of FLT3 (FLT3/ITD) induces increased ROS production, DNA damage, and misrepair: implications for poor prognosis in AML. Blood 2008; 111:3173-82. [PMID: 18192505 DOI: 10.1182/blood-2007-05-092510] [Citation(s) in RCA: 224] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Activating mutations of the FMS-like tyrosine kinase-3 (FLT3) receptor occur in approximately 30% of acute myeloid leukemia (AML) patients and, at least for internal tandem duplication (ITD) mutations, are associated with poor prognosis. FLT3 mutations trigger downstream signaling pathways including RAS-MAP/AKT kinases and signal transducer and activator of transcription-5 (STAT5). We find that FLT3/ITD mutations start a cycle of genomic instability whereby increased reactive oxygen species (ROS) production leads to increased DNA double-strand breaks (DSBs) and repair errors that may explain aggressive AML in FLT3/ITD patients. Cell lines transfected with FLT3/ITD and FLT3/ITD-positive AML cell lines and primary cells demonstrate increased ROS. Increased ROS levels appear to be produced via STAT5 signaling and activation of RAC1, an essential component of ROS-producing NADPH oxidases. A direct association of RAC1-GTP binding to phosphorylated STAT5 (pSTAT5) provides a possible mechanism for ROS generation. A FLT3 inhibitor blocked increased ROS in FLT3/ITD cells resulting in decreased DSB and increased repair efficiency and fidelity. Our study suggests that the aggressiveness of the disease and poor prognosis of AML patients with FLT3/ITD mutations could be the result of increased genomic instability that is driven by higher endogenous ROS, increased DNA damage, and decreased end-joining fidelity.
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Azad N, Rojanasakul Y, Vallyathan V. Inflammation and lung cancer: roles of reactive oxygen/nitrogen species. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART B, CRITICAL REVIEWS 2008; 11:1-15. [PMID: 18176884 DOI: 10.1080/10937400701436460] [Citation(s) in RCA: 270] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
The lung is a highly specialized organ that facilitates uptake of oxygen and release of carbon dioxide. Due to its unique structure providing enormous surface area to outside ambient air, it is vulnerable to numerous pathogens, pollutants, oxidants, gases, and toxicants that are inhaled continuously from air, which makes the lung susceptible to varying degrees of oxidative injury. To combat these unrelenting physical, chemical, and biological insults, the respiratory epithelium is covered with a thin layer of lining fluid containing several antioxidants and surfactants. Inhaled toxic agents stimulate the generation of reactive oxygen/nitrogen species (ROS/RNS), which in turn provoke inflammatory responses resulting in the release of proinflammatory cytokines and chemokines. These subsequently stimulate the influx of polymorphonuclear leukocytes (PMNs) and monocytes into the lung so as to combat the invading pathogens or toxic agents. In addition to the beneficial effects, persistent inhalation of the invading pathogens or toxic agents may result in overwhelming production of ROS/RNS, producing chronic inflammation and lung injury. During inflammation, enhanced ROS/RNS production may induce recurring DNA damage, inhibition of apoptosis, and activation of proto-oncogenes by initiating signal transduction pathways. Therefore, it is conceivable that chronic inflammation-induced production of ROS/RNS in the lung may predispose individuals to lung cancer. This review describes the complex relationship between lung inflammation and carcinogenesis, and highlights the role of ROS/RNS in cancer development.
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Affiliation(s)
- Neelam Azad
- Department of Pharmaceutical and Pharmacological Sciences, West Virginia University, Morgantown, West Virginia, USA
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Molinuevo MS, Cortizo AM, Etcheverry SB. Vanadium(IV) complexes inhibit adhesion, migration and colony formation of UMR106 osteosarcoma cells. Cancer Chemother Pharmacol 2007; 61:767-73. [PMID: 17576559 DOI: 10.1007/s00280-007-0532-6] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2006] [Accepted: 05/05/2007] [Indexed: 11/28/2022]
Abstract
Vanadium is a trace element widely distributed in the environment. In vertebrates it is mainly stored in bone tissue. The unique cellular environment in the bone and the variety of interactions that mediate cancer metastasis determine that certain types of cancer, such as breast and prostate cancer, preferentially metastize in the skeleton. Since this effect usually signifies serious morbidity and grave prognosis there is an increasing interest in the development of new treatments for this pathology. The present work shows that vanadium complexes can inhibit some parameters related to cancer metastasis such as cell adhesion, migration and clonogenicity. We have also investigated the role of protein kinase A in these processes.
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Affiliation(s)
- María S Molinuevo
- Cátedra de Bioquímica Patológica, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, 47 y 115, 1900, La Plata, Argentina
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Hristov KK, Knox KA, Mitev VI. Vanadate-induced inhibition of BCR-triggered apoptosis is coupled with tyrosine phosphorylation and induction of G2M growth arrest in Ramos-BL B cells. Immunol Invest 2007; 36:293-306. [PMID: 17558712 DOI: 10.1080/08820130601069814] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
The regulation of the tyrosine phosphorylation of key signaling molecules by tyrosine kinases and phosphatases is essential for BCR-triggered signaling cascades during B cell selection process. We used the non-selective tyrosine phosphatase inhibitor vanadate to study the importance of the late regulation of the tyrosine phosphorylation for BCR-triggered G1 growth arrest and apoptosis in Ramos-BL B cells. Vanadate induces G2M growth arrest in a dose-dependent manner and prevents BCR-triggered apoptosis. Vanadate-induced upregulation of the tyrosine phosphorylation is concomitant with increased expression of cyclin B and inhibition of caspase-3 activation and PARP cleavage. The anti-apoptotic effect of vanadate was observed even when added up to 6 hours after the treatment of Ramos-BL B cells with anti-IgM. Vanadate increases BCR-triggered tyrosine phosphorylation of the cytosolic tyrosine phosphatases, SHP-1 and SHP-2 after 24 hours. Co-stimulation with anti-CD40 prevents anti-IgM-triggered tyrosine phosphorylation of these phosphatases and up-regulates the expression of SHP-1. We conclude that the regulation of the tyrosine phosphatase activity is indispensable for BCR-triggered execution of the apoptosis in Ramos-BL B cells.
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Affiliation(s)
- Kroum K Hristov
- Department of Biochemistry, South Parks Road, University of Oxford, UK
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Capella MAM, Capella LS, Valente RC, Gefé M, Lopes AG. Vanadate-induced cell death is dissociated from H2O2 generation. Cell Biol Toxicol 2007; 23:413-20. [PMID: 17457679 DOI: 10.1007/s10565-007-9003-4] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2006] [Accepted: 02/07/2007] [Indexed: 10/25/2022]
Abstract
Vanadium is an environmentally toxic metal with peculiar and sometimes contradictory cellular effects. It is insulin-mimetic, it can either stimulate cell growth or induce cell death, and it has both mutagenic and antineoplastic properties. However, the mechanisms involved in those effects are poorly understood. Several studies suggest that H(2)O(2) is involved in vanadate-induced cell death, but it is not known whether cellular sensitivity to vanadate is indeed related to H(2)O(2) generation. In the present study, the sensitivity of four cell lines from different origins (K562, K562-Lucena 1, MDCK, and Ma104) to vanadate and H(2)O(2) was evaluated and the production of H(2)O(2) by vanadate was analyzed by flow cytometry. We show that cell lines very resistant to H(2)O(2) (K562, K562-Lucena 1, and Ma104 cells) are much more sensitive to vanadate than MDCK, a cell line relatively susceptible to H(2)O(2), suggesting that vanadate-induced cytotoxicity is not directly related to H(2)O(2) responsiveness. In accordance, vanadate concentrations that reduced cellular viability to approximately 60-70% of the control (10 mumol/L) did not induce H(2)O(2) formation. A second hypothesis, that peroxovanadium (PV) compounds, produced once vanadate enters into the cells, are responsible for the cytotoxicity, was only partially confirmed because MDCK cells were resistant to both vanadate and PV compounds (10 micromol/L each). Therefore, our results suggest that vanadate toxicity occurs by two distinct pathways, one dependent on and one independent of H(2)O(2) production.
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Affiliation(s)
- M A M Capella
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, RJ, Brazil.
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Genomic analysis of human lung fibroblasts exposed to vanadium pentoxide to identify candidate genes for occupational bronchitis. Respir Res 2007; 8:34. [PMID: 17459161 PMCID: PMC1865536 DOI: 10.1186/1465-9921-8-34] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2006] [Accepted: 04/25/2007] [Indexed: 01/24/2023] Open
Abstract
BACKGROUND Exposure to vanadium pentoxide (V2O5) is a cause of occupational bronchitis. We evaluated gene expression profiles in cultured human lung fibroblasts exposed to V2O5 in vitro in order to identify candidate genes that could play a role in inflammation, fibrosis, and repair during the pathogenesis of V2O5-induced bronchitis. METHODS Normal human lung fibroblasts were exposed to V2O5 in a time course experiment. Gene expression was measured at various time points over a 24 hr period using the Affymetrix Human Genome U133A 2.0 Array. Selected genes that were significantly changed in the microarray experiment were validated by RT-PCR. RESULTS V2O5 altered more than 1,400 genes, of which ~300 were induced while >1,100 genes were suppressed. Gene ontology categories (GO) categories unique to induced genes included inflammatory response and immune response, while GO categories unique to suppressed genes included ubiquitin cycle and cell cycle. A dozen genes were validated by RT-PCR, including growth factors (HBEGF, VEGF, CTGF), chemokines (IL8, CXCL9, CXCL10), oxidative stress response genes (SOD2, PIPOX, OXR1), and DNA-binding proteins (GAS1, STAT1). CONCLUSION Our study identified a variety of genes that could play pivotal roles in inflammation, fibrosis and repair during V2O5-induced bronchitis. The induction of genes that mediate inflammation and immune responses, as well as suppression of genes involved in growth arrest appear to be important to the lung fibrotic reaction to V2O5.
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Abstract
Nickel is a widely distributed metal that is industrially applied in many forms. Accumulated epidemiological evidence confirms that exposures to nickel compounds are associated with increased nasal and lung cancer incidence, both in mostly occupational exposures. Although the molecular mechanisms by which nickel compounds cause cancer are still under intense investigation, the carcinogenic actions of nickel compounds are thought to involve oxidative stress, genomic DNA damage, epigenetic effects, and the regulation of gene expression by activation of certain transcription factors related to corresponding signal transduction pathways. The present review summarizes our current knowledge on the molecular mechanisms of nickel carcinogenesis, with special emphasis on the role of nickel induced reactive oxygen species (ROS) and signal transduction pathways.
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Affiliation(s)
- Haitian Lu
- Nelson Institute of Environmental Medicine, School of Medicine, New York University, Tuxedo, New York 10987, USA
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Wörle-Knirsch JM, Kern K, Schleh C, Adelhelm C, Feldmann C, Krug HF. Nanoparticulate vanadium oxide potentiated vanadium toxicity in human lung cells. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2007; 41:331-6. [PMID: 17265967 DOI: 10.1021/es061140x] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Metal oxides may hold, as nanosized particles, a toxic potential to human health and the environment that is not present in the bulk material. Due to the high surface-to-volume ratio, small amounts can lead to strong oxidative damage within biological systems, impairing cellularfunctions as a consequence of their high surface reactivity. We report here on a new nanosized V203 material that has a needle-like structure with diameters of less than 30 nm and variable lengths. The potentiated toxicity of nanoscale vanadium oxide (V203) compared to bulk material is demonstrated here in human endo- and epithelial lung cells, and might be due to the higher catalytic surface of the particles. Reduction in cell viability is almost ten times stronger and starts with lowest concentrations of "nanoscaled" material (10 microg/mL). Vanadium oxide leads to an induction of heme oxygenase 1 (HO-1) in a dose dependent manner in ECV304 cells whereas a reduction in protein levels can be observed for the epithelial cells (A549). Lipid peroxidation can be observed also for "nanoscaled" vanadium oxide to a much stronger extent in macrophages (RAW cells) than for bulk material. The observed effects can not only be explained by oxidation from V2O3 to V2O5 as there are significant differences between the novel nano vanadium and all used bulk materials (V203 and V205). It appears rather to be a nanoeffect of a high surface reactivity, here coupled with a yet unknown toxicity potentiating effect of a technically important catalyst.
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Affiliation(s)
- Jörg M Wörle-Knirsch
- Department of Molecular Environmental Toxicology, Institute of Toxicology and Genetics, Forschungszentrum Karlsruhe
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Ruocco KM, Goncharova EI, Young MR, Colburn NH, McMahon JB, Henrich CJ. A high-throughput cell-based assay to identify specific inhibitors of transcription factor AP-1. ACTA ACUST UNITED AC 2006; 12:133-9. [PMID: 17175522 DOI: 10.1177/1087057106296686] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The oncogenic transcription factor AP-1 (activator protein-1) is required for tumor promotion and progression. Identification of novel and specific AP-1 inhibitors would be beneficial for cancer prevention and therapy. The authors have developed a high-throughput assay to screen synthetic and natural product libraries for noncytotoxic inhibitors of mitogen-activated AP-1 activity. The cell-based high-throughput screen is conducted in a 384-well format using a fluorescent resonance energy transfer (FRET) substrate to quantify the activity of a beta-lactamase reporter under the control of an AP-1-dependent promoter. The ratiometric FRET readout makes this assay extremely robust and reproducible, particularly for use with natural product extracts. To eliminate false positives due to cell killing, a cytotoxicity assay was incorporated. The AP-1 beta-lactamase reporter was validated with inhibitors of kinases located upstream of AP-1 and with known natural product inhibitors of AP-1 (nordihydroguaiaretic acid and curcumin). The assay was able to identify other known AP-1 inhibitors and protein kinase C modulators, as well as a number of chemically diverse compounds with unknown mechanisms of action from natural products libraries. Application to natural product extracts identified hits from a range of taxonomic groups. Screening of synthetic compounds and natural products should identify novel AP-1 inhibitors that may be useful in the prevention and treatment of cancers.
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Affiliation(s)
- Katie M Ruocco
- Laboratory of Cancer Prevention, Gene Regulation Section, National Cancer Institute-Frederick, Frederick, MD, USA
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Qin G, Meng Z. The expressions of protooncogenes and CYP1A in lungs of rats exposed to sulfur dioxide and benzo(a)pyrene. Regul Toxicol Pharmacol 2006; 45:36-43. [PMID: 16616405 DOI: 10.1016/j.yrtph.2006.02.006] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2006] [Indexed: 11/16/2022]
Abstract
Sulfur dioxide (SO2) is a ubiquitous air pollutant, present in low concentrations in the urban air, and in higher concentrations in the working environment. Benzo(a)pyrene (B(a)P), a polycyclic aromatic hydrocarbon, is a ubiquitous environmental contaminant with diverse toxicological effects. To investigate the interactions between SO2 and B(a)P, male Wistar rats were exposed to intratracheally instilled with benzo(a)pyrene (B(a)P; 3 mg) or SO2 (20 ppm) inhalation alone or together. The mRNA of CYP1A1 and 1A2, c-fos, and c-jun and protein levels of c-fos and c-jun were analyzed in lungs using a real-time reverse transcription-polymerase chain reaction (real-time RT-PCR) assay and Western blot analysis, respectively. And 7-ethoxyresorufin O-deethylase (EROD) and methoxyresorufin O-demethylase (MROD) activities were detected. In lungs of rats exposed to SO2 alone, the gene transcription of CYP1A1 and 1A2, the EROD and MROD activities were decreased. Meanwhile, the mRNA and protein levels of c-jun and c-fos were increased significantly. Exposure to B(a)P alone induced CYP1A1, CYP1A2 mRNA levels, the protein levels of c-jun, and the EROD and MROD activities in lungs. However, exposure to B(a)P plus inhaled SO2 neither increased nor decreased CYP1A1/2 mRNA expressions, EROD, and MROD activities in lungs, versus exposure to B(a)P alone. Nevertheless, exposure to B(a)P plus inhaled SO2 increased the mRNA and protein levels of c-jun and c-fos in lungs compared with lungs exposed to SO2 alone. Accordingly, the SO2-induced decreases of CYP1A1/2 might not influence the metabolic activation of B(a)P. However, when B(a)P and SO2 were given in the combinations, one might postulate that a synergistic effect on the expressions of c-fos and c-jun between SO2 and B(a)P, which might be one of the possible mechanisms of combination effects between B(a)P and the air pollutants.
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Affiliation(s)
- Guohua Qin
- Institute of Environmental Medicine and Toxicology, Shanxi University, Taiyuan 030006, China.
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Finch JS, Tome ME, Kwei KA, Bowden GT. Catalase reverses tumorigenicity in a malignant cell line by an epidermal growth factor receptor pathway. Free Radic Biol Med 2006; 40:863-75. [PMID: 16520238 DOI: 10.1016/j.freeradbiomed.2005.10.036] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/27/2005] [Revised: 10/04/2005] [Accepted: 10/10/2005] [Indexed: 11/30/2022]
Abstract
We have used a keratinocyte in vivo/in vitro cell model to test the hypothesis that hydrogen peroxide acts as a signaling molecule, contributing to proliferation and tumorigenesis. A cell line, 6M90, that produces squamous cell carcinoma (SCC), has high levels of ROS and low levels of catalase. A new cell line, MTOC2, generated from parental 6M90 cells by introduction of a Tet-responsive catalase transgene, effectively expressed higher peroxisomal catalase. Increased catalase expression diminished constitutive ROS and enhanced viability after treatment with hydrogen peroxide. Protein tyrosine phosphatase activity was higher in the MTOC2 cells with high catalase, consistent with detection of a lower level of phosphorylation at tyrosine 1068 of the epidermal growth factor receptor (EGF-R). Transcription of downstream c-fos, AP-1 transactivation and cell proliferation were higher in the low catalase cells. An EGF-R inhibitor, AG1478, blocks the higher AP-1 transactivation and cell proliferation of the low catalase 6M90 cells. Tumorigenesis in SCID mice was greatly diminished in the high catalase cells. Our data suggest that hydrogen peroxide functions as a signaling molecule that can modulate activity of a protein tyrosine phosphatase/(s) resulting in phosphorylation of tryrosine/(s) on the EGF-R. Therefore, catalase acts as a tumor-suppressor gene in part by decreasing EGF-R signaling.
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Affiliation(s)
- Joanne S Finch
- Arizona Cancer Center, University of Arizona, Tucson, 85724, USA
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Gwinn MR, Vallyathan V. Respiratory burst: role in signal transduction in alveolar macrophages. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART B, CRITICAL REVIEWS 2006; 9:27-39. [PMID: 16393868 DOI: 10.1080/15287390500196081] [Citation(s) in RCA: 92] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Alveolar macrophages play an important role in defense against airborne pathogens and particles. These macrophages respond through both the adaptive and acquired immune responses, and through the activation of a multitude of signaling pathways. One major macrophage defense mechanism is respiratory burst, the production of reactive oxygen species (ROS). While the ROS produced may act directly in pathogen killing, they may also be involved as secondary signaling messengers. This review focuses on the activation of four main signaling pathways following the production of reactive oxygen species. These pathways include the nuclear factor kappa beta (NFkB), activating protein-1 (AP-1), mitogen-activating protein kinase (MAPK), and phosphotidyl inositol-3 kinase (PI3K) pathways. This review also briefly examines the role of ROS in DNA damage, in particular looking at the base excision repair pathway (BER), the main pathway involved in repair of oxidative DNA damage. This review highlights many of the studies in the field of ROS, signal transduction, and DNA damage; however, work still remains to further elucidate the role of ROS in disease.
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Affiliation(s)
- Maureen R Gwinn
- Pathology and Physiology Research Branch, Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Morgantown, West Virginia 26505, USA
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Chien PS, Mak OT, Huang HJ. Induction of COX-2 protein expression by vanadate in A549 human lung carcinoma cell line through EGF receptor and p38 MAPK-mediated pathway. Biochem Biophys Res Commun 2005; 339:562-8. [PMID: 16300728 DOI: 10.1016/j.bbrc.2005.11.045] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2005] [Accepted: 11/03/2005] [Indexed: 01/22/2023]
Abstract
Vanadate is a transition metal widely distributed in the environment. It has been reported that vanadate associated with air pollution particles can modify DNA synthesis, causing cell growth arrest, and apoptosis. Moreover, vanadium exposure was also found to cause the synthesis of inflammatory cytokines, such as interleukin-1, tumor necrosis factor-alpha, and prostaglandin E(2). Here, we found that exposure of A549 human lung carcinoma cells to vanadate led to extracellular signal-regulated kinase, c-Jun NH(2)-terminal protein kinases (JNKs), p38 mitogen-activated protein kinase (p38) activation, and COX-2 protein expression in a dose-dependent manner. SB203580, a p38 MAPK inhibitor, but not PD098059 and SP600125, specific inhibitor of MKK1 and selective inhibitor of JNK, respectively, suppressed COX-2 expression. Furthermore, the epithelial growth factor (EGF) receptor specific inhibitor (PD153035) reduced vanadate-induced COX-2 expression. However, scavenging of vanadate-induced reactive oxygen species by catalase, a specific H(2)O(2) inhibitor, or DPI, an NADPH oxidase inhibitor, resulted in no inhibition on COX-2 expression. Together, we suggested that EGF receptor and p38 MAPK signaling pathway may be involved in vanadate-induced COX-2 protein expression in A549 human lung carcinoma cell line.
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Affiliation(s)
- Pei-Shan Chien
- Institute of Biotechnology, National Cheng Kung University, No. 1 University Rd. 701, Tainan, Taiwan
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Chen DB, Li SM, Qian XX, Moon C, Zheng J. Tyrosine Phosphorylation of Caveolin 1 by Oxidative Stress Is Reversible and Dependent on the c-src Tyrosine Kinase but Not Mitogen-Activated Protein Kinase Pathways in Placental Artery Endothelial Cells1. Biol Reprod 2005; 73:761-72. [PMID: 15958730 DOI: 10.1095/biolreprod.105.040881] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
Acute H(2)O(2) exposure to placental artery endothelial cells induced an array of tyrosine-phosphorylated proteins, including caveolin 1 (CAV1) rapid and transient tyr(14) phosphorylated in a time- and concentration-dependent manner. Basal tyr(14) phosphorylated CAV1 was primarily located at the edges of cells and associated with actin filaments. Phosphorylated CAV1 was markedly increased and diffused with the disorganization of actin filaments at 20 min, disappeared at 120 min treatment with 0.2 mM H(2)O(2). Treatment with H(2)O(2) also disorganized actin filaments and changed cell shape in a time-dependent manner. Pretreatment with antioxidants catalase completely, whereas the other tested superoxide dismutase, N-acetyl-l-cysteine and sodium formate partially attenuated H(2)O(2)-induced CAV1 phosphorylation in a concentration-dependent manner. Acute treatment with H(2)O(2) activated multiple signaling pathways, including the mitogen-activated protein kinases (MAPK) members (MAPK3/1-ERK2/1, MAPK8/9-JNK1/2, and MAPK11-p38(mapk)) and the c-src tyrosine kinase (CSK). Pharmacological studies demonstrated that, among these pathways, only the blockade of CSK activation abolished H(2)O(2)-induced CAV1 phosphorylation. Additionally, H(2)O(2)-induced CAV1 phosphorylation was reversible rapidly (<10 min) upon H(2)O(2) withdrawal. Because maternal and fetal endothelia must make dynamic adaptations to oxidative stress resulting from enhanced pregnancy-specific oxygen metabolism favoring prooxidant production, which is emerging as one of the leading causes of the dysfunctional activated endothelium during pregnancy, these unique features of CAV1 phosphorylation on oxidative stress observed implicate an important role of CAV1 in placental endothelial cell biology during pregnancy.
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Affiliation(s)
- Dong-bao Chen
- Department of Reproductive Medicine, University of California San Diego, La Jolla, 92093, USA.
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Aguirre MV, Juaristi JA, Alvarez MA, Brandan NC. Characteristics of in vivo murine erythropoietic response to sodium orthovanadate. Chem Biol Interact 2005; 156:55-68. [PMID: 16137666 DOI: 10.1016/j.cbi.2005.07.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2005] [Revised: 07/08/2005] [Accepted: 07/08/2005] [Indexed: 11/23/2022]
Abstract
Current knowledge about the effects of vanadium compounds on erythropoiesis is still reduced and even contradictory. The aim of this work was to evaluate the in vivo effects of a single dose of sodium orthovanadate (OV, 33 mg/kg i.p.) on CF-1 mice in a time course study (0-8 days). Murine erythropoiesis was assessed through a combinatory of experimental approaches. Classical peripheral and bone marrow (BM) hematological parameters were determined. Erythroid maturation in blood stream and hemopoietic tissues (59Fe uptake assays), BM erythroid progenitor frequency (clonogenic assays) and erythroid crucial protein expressions for commitment and survival: GATA-1, erythropoietin receptor (Epo-R) and Bcl-xL (immunoblottings) were evaluated. Neither BM cellularities nor BM viabilities changed noticeably during the study. Peripheral reticulocytes showed a biphasic increment on days 2 and 8 post-OV. hematocrits enhanced transiently between days 2 and 4. 59Fe uptake percentages enhanced in peripheral blood nearly two-fold over control values between 4 and 8 days (p<0.01) without changes in BM and spleen. Additionally, mature erythroid BM compartments: polychromatophilic erythroblasts and orthochromatic normoblasts increased by the eighth day. BFU-E colonies remained near basal values during the whole experience, whilst CFU-E colonies raised 60% over control at 8 days post-OV (p<0.05). GATA-1 and Epo-R were significantly over-expressed from the third until the end of the experimental protocol (p<0.01). Surprisingly, Bcl-xL showed a constitutive expression pattern without changes during the experience. Experimental data let us suggest that OV does not to cause bone marrow cytotoxicity and that it accelerates maturation of BM committed erythroid precursors. Moreover, there are significant correlations among erythroid-related protein expressions: GATA-1 and Epo-R and the frequency of CFU-E. In addition, Bcl-xL expression invariance during the time course study would indicate that the stimulatory effect of OV treatment on erythropoiesis was mainly exerted on the maturation of red cell precursors rather than on the antiapoptosis of erythroid terminal progenitors.
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Affiliation(s)
- María Victoria Aguirre
- Department of Biochemistry, Faculty of Medicine, Northeast National University, Moreno 1240, 3400 Corrientes, Argentina
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Takeda S, Mochizuki S, Saini HK, Elimban V, Dhalla NS. Modification of alterations in cardiac function and sarcoplasmic reticulum by vanadate in ischemic-reperfused rat hearts. J Appl Physiol (1985) 2005; 99:999-1005. [PMID: 15879166 DOI: 10.1152/japplphysiol.00234.2005] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
To study the cardioprotective effects of vanadate on ischemia-reperfusion (I/R) injury, isolated rat hearts perfused at constant flow were subjected to global ischemia for 30 min followed by reperfusion for 30 min. In this experimental model, I/R markedly decreased ventricular developed pressure and increased end-diastolic pressure. Pretreatment of hearts with 4 microM vanadate attenuated I/R-induced cardiac dysfunction. The reduction in sarcoplasmic reticulum (SR) Ca2+ uptake and Ca2+ release, as well as SR protein contents for Ca2+-pump ATPase and Ca2+-release channel, was also prevented by vanadate. Pretreatment of hearts with an antioxidant mixture containing superoxide dismutase + catalase exerted effects similar to those of vanadate in I/R hearts. Postischemic treatment of hearts with vanadate or superoxide dismutase + catalase also had beneficial effects on I/R-induced changes in cardiac performance and SR function. Alterations in cardiac function and SR Ca2+ transport due to an oxyradical-generating system (xanthine + xanthine oxidase) or an oxidant (H2O2) were attenuated by treatment with vanadate. These results suggest that vanadate may exert beneficial effects on cardiac performance and SR function in I/R hearts because of its antioxidant action.
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Affiliation(s)
- Satoshi Takeda
- Institute of Cardiovascular Sciences, St. Boniface General Hospital Research Centre, 351 Tache Ave., Winnipeg, MB, Canada R2H 2A6
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Feng R, Bowman LL, Lu Y, Leonard SS, Shi X, Jiang BH, Castranova V, Vallyathan V, Ding M. Blackberry extracts inhibit activating protein 1 activation and cell transformation by perturbing the mitogenic signaling pathway. Nutr Cancer 2005; 50:80-9. [PMID: 15572301 DOI: 10.1207/s15327914nc5001_11] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
Blackberries are natural rich sources of bioflavonoids and phenolic compounds that are commonly known as potential chemopreventive agents. Here, we investigated the effects of fresh blackberry extracts on proliferation of cancer cells and neoplastic transformation induced by 12-O-tetradecanoylphorbol-13-acetate (TPA), as well as the underlying mechanisms of signal transduction pathways. Using electron spin resonance, we found that blackberry extract is an effective scavenger of free radicals, including hydroxyl and superoxide radicals. Blackberry extract inhibited the proliferation of a human lung cancer cell line, A549. Pretreatment of A549 cells with blackberry extract resulted in an inhibition of 8-hydroxy-2'-deoxyguanosine (8-OHdG) formation induced by ultraviolet B (UVB) irradiation. Blackberry extract decreased TPA-induced neoplastic transformation of JB6 P+ cells. Pretreatment of JB6 cells with blackberry extract resulted in the inhibition of both UVB- and TPA-induced AP-1 transactivation. Furthermore, blackberry extract also blocked UVB- or TPA-induced phosphorylation of ERKs and JNKs, but not p38 kinase. Overall, these results indicated that an extract from fresh blackberry may inhibit tumor promoter-induced carcinogenesis and associated cell signaling, and suggest that the chemopreventive effects of fresh blackberry may be through its antioxidant properties by blocking reactive oxygen species-mediated AP-1 and mitogen-activated protein kinase activation.
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Affiliation(s)
- Rentian Feng
- Pathology and Physiology Research Branch, Helath Effects Laboratory Division, National Institute for Occupational Safety and Health, Morgantown, WV 26505, USA
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Leonard SS, Harris GK, Shi X. Metal-induced oxidative stress and signal transduction. Free Radic Biol Med 2004; 37:1921-42. [PMID: 15544913 DOI: 10.1016/j.freeradbiomed.2004.09.010] [Citation(s) in RCA: 396] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/15/2004] [Revised: 08/24/2004] [Accepted: 09/10/2004] [Indexed: 01/08/2023]
Abstract
Occupational and environmental exposures to metals are associated with the development of various cancers. Although carcinogenesis caused by metals has been intensively investigated, the mechanisms of action, especially at the molecular level, are still unclear. Accumulating evidence indicates that reactive oxygen species generated by metals may play an important role in the etiology of disease. This review covers recent advances in (1) metal-induced generation of reactive oxygen species; (2) the receptors, kinases, and nuclear transcription factors affected by metals and metal-induced oxidative stress, including growth factor receptors, src kinase, ras signaling, mitogen-activated protein kinases, the phosphoinositide 3-phosphate/Akt pathway, nuclear transcription factor kappaB, activator protein 1, p53, nuclear factor of activated T cells, and hypoxia-inducible factor 1; and (3) global cellular phenomena (signal transduction, cell cycle regulation, and apoptosis) associated with metal-induced ROS production and gene expression.
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Affiliation(s)
- Stephen S Leonard
- National Institute for Occupational Safety and Health, Pathology and Physiology Research Branch, Health Effects Laboratory Division, 1095 Willowdale Road, MS/2015, Morgantown, WV 26505, USA.
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Li J, Dokka S, Wang L, Shi X, Castranova V, Yan Y, Costa M, Huang C. Activation of aPKC is required for vanadate-induced phosphorylation of protein kinase B (Akt), but not p70S6k in mouse epidermal JB6 cells. Mol Cell Biochem 2004; 255:217-25. [PMID: 14971662 DOI: 10.1023/b:mcbi.0000007277.90298.24] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Vanadium is a metal widely distributed in the environment. Although vanadate-containing compounds exert potent toxic effects on a wide variety of biological systems, the mechanisms by which vanadate mediates adverse effects are not well understood. The present study investigated the vanadate-induced phosphorylation of Akt and p70S6K, two kinases known to be vital for cell survival, growth, transformation, and transition of the cell cycle in mammals. Exposure of mouse epidermal JB6 cells to vanadium led to phosphorylation of Akt and p70S6K in a time- and dose-dependent manner. Vanadium exposure also caused translocation of atypical isoforms of PKC (lambda, zeta) from the cytosol to the membrane, but had no effect on PKCalpha translocation, suggesting that the atypical PKCs (aPKC) were specifically involved in vanadium-induced cellular response. Importantly, overexpression of a dominant negative mutant PKClambda blocked Akt phosphorylation at Ser473 and Thr308, whereas it did not inhibit p70S6k phosphorylation at Thr389 and Thr421/Ser424, suggesting that aPKC activation is specifically involved in vanadium-induced activation of Akt, but not in activation of p70S6k. Furthermore, vanadium-induced p70S6k phosphorylation at Thr389 and Thr421/Ser424 and Akt phosphorylation at Thr308 occurred through a PI-3K-dependent pathway because a PI-3K dominant negative mutant inhibited induction as compared with vector control cells. These results indicate that there was a differential role of aPKC in vanadate-induced phosphorylation of Akt and p70S6k, suggesting that signal transduction pathways leading to the activation of Akt and p70S6k were different.
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Affiliation(s)
- Jingxia Li
- Nelson Institute of Environmental Medicine, New York University School of Medicine, Tuxedo, NY 10987, USA
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50
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Gao N, Shen L, Zhang Z, Leonard SS, He H, Zhang XG, Shi X, Jiang BH. Arsenite induces HIF-1alpha and VEGF through PI3K, Akt and reactive oxygen species in DU145 human prostate carcinoma cells. Mol Cell Biochem 2004; 255:33-45. [PMID: 14971644 DOI: 10.1023/b:mcbi.0000007259.65742.16] [Citation(s) in RCA: 94] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Arsenite is widely distributed environmental toxicant in water, food and air. It is a known human carcinogen, which is strongly associated with human cancers originated from liver, nasal cavity, lung, skin, bladder, kidney, and prostate. In this study, we investigated whether arsenite induces expression of hypoxia-inducible factor 1 (HIF-1). HIF-1 is a heterodimeric basic helix-loop-helix transcription factor, composed of HIF-1alpha and HIF-1beta/ARNT subunits; and is involved in tumor growth and angiogenesis. Here we demonstrate that arsenite induces the expression of HIF-1alpha but not HIF-1beta subunit in DU145 human prostate carcinoma cells. Arsenite also increases the expression of VEGF through the induction of HIF-1. We also found that arsenite activates PI3K and Akt that are required for arsenite-induced expression of HIF-1alpha and VEGF. The induction of HIF-1 and VEGF by arsenite can not be inhibited by MAP kinase inhibitors. Arsenite causes production of reactive oxygen species (ROS). The major species of ROS required for the induction of HIF-1 and VEGF is H2O2. These data indicate that the arsenite-induced activation of PI3K/Akt signaling and the expression of HIF-1 and VEGF through the generation of ROS could be an important mechanism in the arsenite-induced carcinogenesis.
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Affiliation(s)
- Ning Gao
- Mary Babb Randolph Cancer Center, Department of Microbiology, Immunology and Cell Biology, West Virginia University, Morgantown, WV 26506, USA
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