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Zhu Z, Li W, Lai Y, Carter O, Banerjee S, Sadler PJ, Huang H. Photocatalytic glucose-appended bio-compatible Ir(III) anticancer complexes. Dalton Trans 2022; 51:10875-10879. [DOI: 10.1039/d2dt01134d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Rationally-designed glucose-appended Ir(III) photo-catalysts ([Ir(N,C)2(N,N-Glc)]+, Ir1-Ir3) show visible light-induced catalytic NAD(P)H oxidation in aqueous solution. Highly in-vivo biocompatible complex, Ir3, shows lysosome and mitochondria targeting necro-apoptotic photo-cytotoxicity against various cancer...
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Mony V, Nirmal RM, Parvathi V, Parvathy RL, Varun BR, Jayanthi P. Evaluation of aryl hydrocarbon receptor expression in oral squamous cell carcinoma and normal oral mucosa using western blot. J Oral Maxillofac Pathol 2021; 25:68-73. [PMID: 34349414 PMCID: PMC8272475 DOI: 10.4103/jomfp.jomfp_287_20] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Revised: 08/10/2020] [Accepted: 09/22/2020] [Indexed: 11/04/2022] Open
Abstract
Background Aryl hydrocarbon receptor (AHR) is a ligand-activated transcription factor that acts as a binding site for toxic chemicals, particularly the dioxin group of chemicals. Elevated levels of AHR have been observed in various human cancers, including lung carcinomas, hepatic carcinomas and in mammary tumors. However, the expression of AHR in oral squamous cell carcinoma (OSCC) patients who are tobacco users are less explored. Aims and Objectives The aim of the present study is to evaluate and compare AHR levels in OSSC patients and in normals using Western blot technique in an attempt to explore the possible role of AHR in oral carcinogenesis. Materials and Methods The study sample consisted of ten oral squamous cell carcinoma cases which were diagnosed clinically and confirmed histopathologically as OSCC and four samples of the normal oral mucosa. AHR protein expression was evaluated using Western blot technique and chemiluminescence detection kit. The densitometry was performed on a Microtek scan maker MSP flatbed scanner and quantified using Image J software. Mean AHR protein levels were calculated and compared between OSCC and normal oral mucosa using Student's t-test. Results The mean AHR protein level in OSCC samples (n = 10) was 2878.90 ± 1231.27 and 975.75 ± 227.27 in the normal oral mucosa (n = 4). The OSCC samples showed significantly higher levels of AHR protein compared to the normal oral mucosa (P = 0.008). Conclusion The study showed a significantly higher expression of AHR in oral squamous cell carcinoma samples when compared to the normal oral mucosa, suggesting a possible role of AHR in the initiation, promotion and progression of oral squamous cell carcinoma.
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Affiliation(s)
- Vinod Mony
- Department of Oral and Maxillofacial Pathology, PMS College of Dental Sciences and Research, Thiruvananthapuram, Kerala, India
| | - R Madhavan Nirmal
- Department of Oral and Maxillofacial Pathology, Rajah Muthiah Dental College and Hospital, Annamalai University, Chidambaram, Tamil Nadu, India
| | - V Parvathi
- Department of Oral and Maxillofacial Pathology, Rajah Muthiah Dental College and Hospital, Annamalai University, Chidambaram, Tamil Nadu, India
| | - R L Parvathy
- Department of Pharmacology, PMS College of Dental Sciences and Research, Thiruvananthapuram, Kerala, India
| | - B R Varun
- Department of Oral and Maxillofacial Pathology, PMS College of Dental Sciences and Research, Thiruvananthapuram, Kerala, India
| | - P Jayanthi
- Department of Oral and Maxillofacial Pathology, Azeezia College of Dental Sciences and Research, Kollam, Kerala, India
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von Koschembahr A, Youssef A, Béal D, Gudimard L, Giot JP, Douki T. Toxicity and DNA repair in normal human keratinocytes co-exposed to benzo[a]pyrene and sunlight. Toxicol In Vitro 2019; 63:104744. [PMID: 31836489 DOI: 10.1016/j.tiv.2019.104744] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2019] [Revised: 11/21/2019] [Accepted: 12/06/2019] [Indexed: 12/28/2022]
Abstract
Skin has the potential to be exposed to both solar UV radiation and polycyclic aromatic hydrocarbons, especially in occupational environments. In the present work, we investigated how benzo[a]pyrene (B[a]P) modulates cellular phototoxicity and impacts formation and repair of pyrimidine dimers induced by simulated sunlight (SSL) in normal human keratinocytes (NHK). We were especially interested in determining whether the aryl hydrocarbon receptor (AhR) was involved since it was recently shown to negatively impact repair. Addition of 1 μM B[a]P after exposure to 2 minimal erythemal doses of SSL had little impact on NHK. The inverse protocol involving incubation with B[a]P followed by irradiation led to a strong increase in phototoxicity. Repair of DNA photoproducts was drastically impaired. Using agonists and antagonists of AhR allowed us to conclude that this factor was not involved in these results. Observation of a strong increase in the level of the oxidative marker 8-oxo-7,8-dihydroguanine in the protocol involving B[a]P treatment followed by exposure to SSL strongly suggested that a photosensitized oxidative stress was responsible for cell death and inhibition of DNA repair. Accordingly, both adverse effects were diminished with a lower concentration of B[a]P and a lower SSL dose, leading to less oxidative stress.
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Affiliation(s)
- Anne von Koschembahr
- Univ. Grenoble Alpes, SyMMES/CIBEST UMR 5819 UGA-CNRS-CEA, INAC/CEA-Grenoble LAN, F-38000 Grenoble, France
| | - Antonia Youssef
- Univ. Grenoble Alpes, SyMMES/CIBEST UMR 5819 UGA-CNRS-CEA, INAC/CEA-Grenoble LAN, F-38000 Grenoble, France
| | - David Béal
- Univ. Grenoble Alpes, SyMMES/CIBEST UMR 5819 UGA-CNRS-CEA, INAC/CEA-Grenoble LAN, F-38000 Grenoble, France
| | - Leslie Gudimard
- Univ. Grenoble Alpes, SyMMES/CIBEST UMR 5819 UGA-CNRS-CEA, INAC/CEA-Grenoble LAN, F-38000 Grenoble, France
| | - Jean-Philippe Giot
- Service de Chirurgie Plastique et Maxillo-faciale, Centre Hospitalier Universitaire Grenoble Alpes, La Tronche, France
| | - Thierry Douki
- Univ. Grenoble Alpes, SyMMES/CIBEST UMR 5819 UGA-CNRS-CEA, INAC/CEA-Grenoble LAN, F-38000 Grenoble, France.
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Fritsch-Decker S, Marquardt C, Stoeger T, Diabaté S, Weiss C. Revisiting the stress paradigm for silica nanoparticles: decoupling of the anti-oxidative defense, pro-inflammatory response and cytotoxicity. Arch Toxicol 2018; 92:2163-2174. [DOI: 10.1007/s00204-018-2223-y] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Accepted: 05/17/2018] [Indexed: 01/04/2023]
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Toxicity of wood smoke particles in human A549 lung epithelial cells: the role of PAHs, soot and zinc. Arch Toxicol 2016; 90:3029-3044. [DOI: 10.1007/s00204-016-1659-1] [Citation(s) in RCA: 68] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2015] [Accepted: 01/04/2016] [Indexed: 10/22/2022]
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6
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Schreck I, Grico N, Hansjosten I, Marquardt C, Bormann S, Seidel A, Kvietkova DL, Pieniazek D, Segerbäck D, Diabaté S, van der Horst GTJ, Oesch-Bartlomowicz B, Oesch F, Weiss C. The nucleotide excision repair protein XPC is essential for bulky DNA adducts to promote interleukin-6 expression via the activation of p38-SAPK. Oncogene 2015; 35:908-18. [PMID: 25982271 DOI: 10.1038/onc.2015.145] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2014] [Revised: 02/20/2015] [Accepted: 03/20/2015] [Indexed: 12/17/2022]
Abstract
Polycyclic aromatic hydrocarbons (PAHs) are environmental pollutants, and many are potent carcinogens. Benzo[a]pyrene (B[a]P), one of the best-studied PAHs, is metabolized ultimately to the genotoxin anti-B[a]P-7,8-dihydrodiol-9,10-epoxide (BPDE). BPDE triggers stress responses linked to gene expression, cell death and survival. So far, the underlying mechanisms that initiate these signal transduction cascades are unknown. Here we show that BPDE-induced DNA damage is recognized by DNA damage sensor proteins to induce activation of the stress-activated protein kinase (SAPK) p38. Surprisingly, the classical DNA damage response, which involves the kinases ATM and ATR, is not involved in p38-SAPK activation by BPDE. Moreover, the induction of p38-SAPK phosphorylation also occurs in the absence of DNA strand breaks. Instead, increased phosphorylation of p38-SAPK requires the nucleotide excision repair (NER) and DNA damage sensor proteins XPC and mHR23B. Interestingly, other genotoxins such as cisplatin (CDDP), hydrogen peroxide and ultraviolet radiation also enhance XPC-dependent p38-SAPK phosphorylation. In contrast, anti-benzo[c]phenanthrene-3,4-dihydrodiol-1,2-epoxide, the DNA adducts of which are not properly recognized by NER, does not trigger p38-SAPK activation. As a downstream consequence, expression and secretion of the pro-inflammatory cytokine interleukin-6 is induced by BPDE and CDDP in vitro and by CDDP in the murine lung, and depends on XPC. In conclusion, we describe a novel pathway in which DNA damage recognition by NER proteins specifically leads to activation of p38-SAPK to promote inflammatory gene expression.
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Affiliation(s)
- I Schreck
- Institute of Toxicology and Genetics, KIT Campus North, Eggenstein-Leopoldshafen, Germany
| | - N Grico
- Institute of Toxicology and Genetics, KIT Campus North, Eggenstein-Leopoldshafen, Germany.,Institute of Toxicology, University of Mainz, Mainz, Germany
| | - I Hansjosten
- Institute of Toxicology and Genetics, KIT Campus North, Eggenstein-Leopoldshafen, Germany
| | - C Marquardt
- Institute of Toxicology and Genetics, KIT Campus North, Eggenstein-Leopoldshafen, Germany
| | - S Bormann
- Institute of Toxicology and Genetics, KIT Campus North, Eggenstein-Leopoldshafen, Germany
| | - A Seidel
- Biochemical Institute for Environmental Carcinogens, Lurup 4, Grosshansdorf, Germany
| | - D L Kvietkova
- Department of Biosciences and Nutrition, Karolinska Institutet, Novum, S-14183 Huddinge, Sweden
| | - D Pieniazek
- Department of Biosciences and Nutrition, Karolinska Institutet, Novum, S-14183 Huddinge, Sweden
| | - D Segerbäck
- Department of Biosciences and Nutrition, Karolinska Institutet, Novum, S-14183 Huddinge, Sweden
| | - S Diabaté
- Institute of Toxicology and Genetics, KIT Campus North, Eggenstein-Leopoldshafen, Germany
| | - G T J van der Horst
- MGC, Department of Genetics, Erasmus University Medical Center, Rotterdam, The Netherlands
| | | | - F Oesch
- Institute of Toxicology, University of Mainz, Mainz, Germany
| | - C Weiss
- Institute of Toxicology and Genetics, KIT Campus North, Eggenstein-Leopoldshafen, Germany
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Madureira DJ, Weiss FT, Van Midwoud P, Helbling DE, Sturla SJ, Schirmer K. Systems toxicology approach to understand the kinetics of benzo(a)pyrene uptake, biotransformation, and DNA adduct formation in a liver cell model. Chem Res Toxicol 2014; 27:443-53. [PMID: 24446834 DOI: 10.1021/tx400446q] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Cell-based models are important for deriving mechanistic information about stress response pathways that have evolved to protect cells from toxic insult, such as exposure to environmental pollutants. One determinant of the stress response is the amount of chemical entering the cell and the cell's ability to detoxify and remove the chemical. If the stress response is overwhelmed, an adverse outcome will ensue. It was the goal of our study to quantify uptake and elimination rates of benzo(a)pyrene (BaP), a ubiquitous environmental pollutant, in a murine liver cell line. We evaluated the kinetic behavior in the context of BaP uptake, biotransformation, DNA adduct formation and repair along with the transcriptional and cell proliferation response. A low (50 nM) and a high (5 μM) BaP concentration were chosen in order to differentiate the role of exposure concentration in the time-resolved interaction of BaP with cells. While rates of uptake and the initial transcriptional response were similar for both BaP concentrations, cells exposed to 50 nM BaP completely recovered from exposure within 24 h, whereas cells exposed to 5 μM BaP did not. Biotransformation proceeded faster on 50 nM BaP, and the few DNA adducts formed were completely repaired after transient cell cycle arrest. In contrast, DNA adducts greatly accumulated in cells exposed to 5 μM BaP, despite significant biotransformation; complete cell cycle arrest and toxicity evolved. On the basis of the kinetic rate constants and cellular response, we conclude that at least short-term, pulsed exposures to 50 nM BaP, which we consider environmentally relevant, can be handled by cells without adverse outcome. Further studies are needed to determine the ability of cells to recover from repeated exposure. Our study emphasizes the importance of quantifying chemical uptake and fate in cell models to differentiate a stress response from an adverse outcome for better risk assessment.
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Affiliation(s)
- Danielle J Madureira
- Eawag, Swiss Federal Institute of Aquatic Science and Technology , Dübendorf, Switzerland
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Lizarraga D, Gaj S, Brauers KJ, Timmermans L, Kleinjans JC, van Delft JHM. Benzo[a]pyrene-induced changes in microRNA-mRNA networks. Chem Res Toxicol 2012; 25:838-49. [PMID: 22316170 DOI: 10.1021/tx2003799] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Toxicological studies assessing the safety of compounds for humans frequently use in vitro systems to characterize toxic responses in combination with transcriptomic analyses. Thus far, changes have mostly been investigated at the mRNA level. Recently, microRNAs have attracted attention because they are powerful negative regulators of mRNA levels and, thus, may be responsible for the modulation of important mRNA networks implicated in toxicity. This study aimed to identify possible microRNA-mRNA networks as novel interactions on the gene expression level after a genotoxic insult. We used benzo[a]pyrene (BaP), a polycyclic aromatic hydrocarbon, as a model genotoxic/carcinogenic compound. We analyzed time-dependent effects on mRNA and microRNA profiles in HepG2 cells, a widely used human liver cell line that expresses active p53 and is competent for the biotransformation of BaP. Changes in microRNA expression in response to BaP, in combination with multiple alterations of mRNA levels, were observed. Many of these altered mRNAs are targets of altered microRNAs. Using pathway analysis, we evaluated the relevance of such microRNA deregulations to genotoxicity. This revealed eight microRNAs that appear to participate in specific BaP-responsive pathways relevant to genotoxicity, such as apoptotic signaling, cell cycle arrest, DNA damage response, and DNA damage repair. Our results particularly highlight the potential of microRNA-29b, microRNA-26a-1*, and microRNA-122* as novel players in the BaP response. Therefore, this study demonstrates the added value of an integrated microRNA-mRNA approach for identifying molecular mechanisms induced by BaP in an in vitro human model.
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Affiliation(s)
- Daneida Lizarraga
- Netherlands Toxicogenomics Centre, Maastricht University , P.O. Box 616, 6200 MD, Maastricht, The Netherlands
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Burkhardt B, Jung SA, Pfeiffer E, Weiss C, Metzler M. Mouse hepatoma cell lines differing in aryl hydrocarbon receptor-mediated signaling have different activities for glucuronidation. Arch Toxicol 2011; 86:643-9. [DOI: 10.1007/s00204-011-0789-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2011] [Accepted: 11/21/2011] [Indexed: 01/19/2023]
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Schreck I, Deigendesch U, Burkhardt B, Marko D, Weiss C. The Alternaria mycotoxins alternariol and alternariol methyl ether induce cytochrome P450 1A1 and apoptosis in murine hepatoma cells dependent on the aryl hydrocarbon receptor. Arch Toxicol 2011; 86:625-32. [PMID: 22120949 DOI: 10.1007/s00204-011-0781-3] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2011] [Accepted: 11/10/2011] [Indexed: 12/16/2022]
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Role and interaction of p53, BAX and the stress-activated protein kinases p38 and JNK in benzo(a)pyrene-diolepoxide induced apoptosis in human colon carcinoma cells. Arch Toxicol 2011; 86:329-37. [PMID: 21983885 DOI: 10.1007/s00204-011-0757-3] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2011] [Accepted: 09/19/2011] [Indexed: 12/14/2022]
Abstract
Polycyclic aromatic hydrocarbons are ubiquitous environmental pollutants formed during incomplete combustion of organic material. For example benzo[a]pyrene (B[a]P) is a constituent and contaminant of cigarette smoke, automobile exhaust, industrial waste and even food products. B[a]P is carcinogenic to rodents and humans. B[a]P induces its own metabolism, which generates different metabolites such as the highly reactive electrophilic genotoxin and ultimal carcinogen B[a]P-7,8-dihydrodiol-9,10-epoxide (BPDE). BPDE can bind to nucleophilic macromolecules such as proteins and DNA and causes mutations. Multiple defence mechanisms have evolved to protect the cell from DNA damage. Specific signalling pathways operate to detect and repair different kinds of lesions. In case, the damage is poorly removed expansion of damaged cells can be counteracted, e.g., by the inhibition of proliferation or triggering apoptosis. Examples of damage sensors and transducers are stress-activated protein kinases (SAPKs) and the tumour suppressor protein p53. Here, we studied the role of p53 and the pro-apoptotic protein BAX in BPDE-induced cell death by using wild-type- or knock-out-human colon carcinoma cells. As reported previously, we could reconfirm a critical role of p53 in BPDE-induced apoptosis. Furthermore, induced levels of total p53 and its transcriptional target p21 declined at higher BPDE concentrations correlating with reduced rates of apoptosis. Interestingly, increased phosphorylation of p53 at serine 15 remained elevated at higher BPDE concentrations thus disconnecting p53 phosphorylation from downstream apoptosis. Hence, phosphorylation of p53 seems not only to be a more sensitive biomarker of BPDE exposure but might serve other functions unrelated to apoptosis. In addition, we identify BAX as a novel and essential factor to trigger the intrinsic pathway of apoptosis in response to BPDE. Furthermore, BPDE in parallel activates the SAPKs p38 and JNK, which are as well involved in apoptosis. Although several routes of mutual regulation of p53 and SAPK have been described, we present evidence that the SAPK pathway in response to genotoxic stress can unexpectedly operate independently of p53 and controls apoptosis by a novel mechanism possibly downstream of caspases.
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Hrubá E, Vondráček J, Líbalová H, Topinka J, Bryja V, Souček K, Machala M. Gene expression changes in human prostate carcinoma cells exposed to genotoxic and nongenotoxic aryl hydrocarbon receptor ligands. Toxicol Lett 2011; 206:178-88. [DOI: 10.1016/j.toxlet.2011.07.011] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2011] [Revised: 07/11/2011] [Accepted: 07/12/2011] [Indexed: 01/28/2023]
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Indolylfuran, a potent aryl hydrocarbon receptor agonist from sauerkraut, interacts with the oestrogen pathway. Food Chem 2011. [DOI: 10.1016/j.foodchem.2011.02.056] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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Yauk CL, Jackson K, Malowany M, Williams A. Lack of change in microRNA expression in adult mouse liver following treatment with benzo(a)pyrene despite robust mRNA transcriptional response. MUTATION RESEARCH-GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2011; 722:131-9. [DOI: 10.1016/j.mrgentox.2010.02.012] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2010] [Accepted: 02/20/2010] [Indexed: 12/12/2022]
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Schreck I, Al-Rawi M, Mingot JM, Scholl C, Diefenbacher ME, O'Donnell P, Bohmann D, Weiss C. c-Jun localizes to the nucleus independent of its phosphorylation by and interaction with JNK and vice versa promotes nuclear accumulation of JNK. Biochem Biophys Res Commun 2011; 407:735-40. [PMID: 21439937 DOI: 10.1016/j.bbrc.2011.03.092] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2011] [Accepted: 03/20/2011] [Indexed: 12/29/2022]
Abstract
In order to activate gene expression, transcription factors such as c-Jun have to reside in the nucleus. The abundance of c-Jun in the nucleus correlates with the activity of its target genes. As a consequence of excessive c-Jun activation, cells undergo apoptosis or changes in differentiation whereas decreased c-Jun function can reduce proliferation. In the present study we addressed how nuclear accumulation of the transcription factor c-Jun is regulated. First, we analyzed which functions of c-Jun are required for efficient nuclear accumulation. Mutants of c-Jun deficient in dimerization or DNA-binding show no defect in nuclear transport. Furthermore, c-Jun import into the nucleus of living cells occurred when the c-Jun phosphorylation sites were mutated as well in cells that lack the major c-Jun kinase, JNK, suggesting that c-Jun transport into the nucleus does not require JNK signaling. Conversely, however, binding of c-Jun seemed to enhance nuclear accumulation of JNK. In order to identify proteins that might be relevant for the nuclear translocation of c-Jun we searched for novel binding partners by a proteomic approach. In addition to the heat shock protein HSP70 and the DNA damage repair factors Ku70 and 80, we isolated human importin 8 as a novel interactor of c-Jun. Interaction of Imp 8 with c-Jun in human cells was confirmed by co-immunoprecipitation experiments. Nuclear accumulation of c-Jun does not require its functions as a transcription factor or the interaction with its kinase JNK. Interestingly, nuclear accumulation of JNK is regulated by interaction with c-Jun. Unraveling the mechanisms of c-Jun and JNK transport to the nucleus and its regulation will improve our understanding of their role in biological and pathophysiological processes.
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Affiliation(s)
- Ilona Schreck
- Institute of Toxicology and Genetics, Karlsruhe Institute of Technology, Campus North, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
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Chopra M, Schrenk D. Dioxin toxicity, aryl hydrocarbon receptor signaling, and apoptosis-persistent pollutants affect programmed cell death. Crit Rev Toxicol 2011; 41:292-320. [PMID: 21323611 DOI: 10.3109/10408444.2010.524635] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Exogenous ligands of the aryl hydrocarbon receptor (AhR) such as 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and related substances are highly toxic pollutants ubiquitously present in the environment. They cause a variety of toxic effects to different organs and tissues. Among other effects, TCDD exposure to laboratory animals leads to thymus atrophy and immunosuppression on the one hand, and to tumor formation on the other. Apoptosis appears to be involved in both these toxic effects: AhR activation by TCDD was discussed to induce apoptosis of immune cells, leading to the depletion of thymocytes and ultimately immunosuppression. This mechanism could help to explain the highly immunotoxic actions of TCDD but it is nevertheless under debate whether this is the mode of action for immunosuppression by this class of chemical substances. In other cell types, especially liver cells, TCDD inhibits apoptosis induced by genotoxic treatment. In initiation-promotion studies, TCDD was shown to be a potent liver tumor promoter. Among other theories it was hypothesized that TCDD acts as a tumor promoter by preventing initiated cells from undergoing apoptosis. The exact mechanisms of apoptosis inhibition by TCDD are not fully understood, but both in vivo and in vitro studies consistently showed an involvement of the tumor suppressor p53 in this effect. Various strings of evidence have been established linking apoptosis to the detrimental effects of exogenous activation of the AhR. Within this article, studies elucidating the effects of TCDD and related substances on apoptosis signaling, be it inducing or repressing, is to be reviewed.
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Affiliation(s)
- Martin Chopra
- Institute of Food Chemistry and Toxicology, University of Kaiserslautern, Kaiserslautern, Germany
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van Delft JHM, Mathijs K, Staal YCM, van Herwijnen MHM, Brauers KJJ, Boorsma A, Kleinjans JCS. Time Series Analysis of Benzo[A]Pyrene-Induced Transcriptome Changes Suggests That a Network of Transcription Factors Regulates the Effects on Functional Gene Sets. Toxicol Sci 2010; 117:381-92. [DOI: 10.1093/toxsci/kfq214] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
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Potential health-modulating effects of isoflavones and metabolites via activation of PPAR and AhR. Nutrients 2010; 2:241-79. [PMID: 22254019 PMCID: PMC3257647 DOI: 10.3390/nu2030241] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2009] [Accepted: 02/23/2010] [Indexed: 12/24/2022] Open
Abstract
Isoflavones have multiple actions on cell functions. The most prominent one is the activation of estrogen receptors. Other functions are often overlooked, but are equally important and explain the beneficial health effects of isoflavones. Isoflavones are potent dual PPARα/γ agonists and exert anti-inflammatory activity, which may contribute to the prevention of metabolic syndrome, atherosclerosis and various other inflammatory diseases. Some isoflavones are potent aryl hydrocarbon receptor (AhR) agonists and induce cell cycle arrest, chemoprevention and modulate xenobiotic metabolism. This review discusses effects mediated by the activation of AhR and PPARs and casts a light on the concerted action of isoflavones.
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Schellenberger MT, Grova N, Willième S, Farinelle S, Prodhomme EJ, Muller CP. Modulation of Benzo[a]pyrene induced immunotoxicity in mice actively immunized with a B[a]P-diphtheria toxoid conjugate. Toxicol Appl Pharmacol 2009; 240:37-45. [DOI: 10.1016/j.taap.2009.06.019] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2009] [Revised: 06/19/2009] [Accepted: 06/22/2009] [Indexed: 11/26/2022]
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