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Abstract
In recent years there has been much interest in the development of iron (Fe) chelators for treatment of a number of clinical conditions in addition to beta-thalassaemia. These include cancer, anthracycline-mediated cardiotoxicity, malaria, AIDS and the severe neurodegenerative disease, Friedreich's ataxia. In this review I will discuss the most recent advances achieved in the potential treatment of these conditions using Fe chelators.
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Savarino A, Pescarmona GP, Boelaert JR. Iron metabolism and HIV infection: reciprocal interactions with potentially harmful consequences? Cell Biochem Funct 1999; 17:279-87. [PMID: 10587615 DOI: 10.1002/(sici)1099-0844(199912)17:4<279::aid-cbf833>3.0.co;2-j] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Humans with advanced human immunodeficiency virus (HIV) infection present some evidence suggestive of iron accumulation. Ferritin concentrations increase with HIV disease progression, and iron accumulates in several tissues. Iron excess may exert negative effects in individuals with HIV. Indeed, iron accumulation seems to be associated with shorter survival, and a number of investigations point to an iron-mediated oxidative stress in subjects with HIV infection. The observations on humans infected with HIV are in part supported by in-vitro findings. Indeed, in-vitro HIV infection is associated with changes in iron metabolism, and an iron-mediated oxidative stress is likely to contribute to viral cytopathogenicity. Furthermore, it is interesting to point out that the interaction between iron and HIV may be reciprocal, since viruses with a life-cycle involving a DNA phase require chelatable iron for optimum replication. This combined evidence suggests that iron metabolism is an important area for virus/host interaction. These observations may be relevant to both laboratory monitoring and clinical treatment of individuals with HIV.
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Affiliation(s)
- A Savarino
- Departiment of Medical and Surgical Sciences, University of Turin, Turin, Italy
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53
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Epinat JC, Gilmore TD. Diverse agents act at multiple levels to inhibit the Rel/NF-kappaB signal transduction pathway. Oncogene 1999; 18:6896-909. [PMID: 10602465 DOI: 10.1038/sj.onc.1203218] [Citation(s) in RCA: 161] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Rel/NF-kappaB transcription factors regulate several important physiological processes, including developmental processes, inflammation and immune responses, cell growth, cancer, apoptosis, and the expression of certain viral genes. Therefore, they have also been sought-after molecular targets for pharmacological intervention. As details of the Rel/NF-kappaB signal transduction pathway are revealed, it is clear that modulators of this pathway can act at several levels. Inhibitors of the Rel/NF-kappaB pathway include a variety of natural and designed molecules, including anti-oxidants, proteasome inhibitors, peptides, small molecules, and dominant-negative or constitutively active polypeptides in the pathway. Several of these molecules act as general inhibitors of Rel/NF-kappaB induction, whereas others inhibit specific pathways of induction. Inhibitors of Rel/NF-kappaB are likely to gain stature as treatments for certain cancers and neurodegenerative and inflammatory diseases.
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Affiliation(s)
- J C Epinat
- Boston University, Biology Department, 5 Cummington Street, Boston, Massachusetts, MA 02215, USA
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54
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Trelease RB, Henderson RA, Park JB. A qualitative process system for modeling NF-kappaB and AP-1 gene regulation in immune cell biology research. Artif Intell Med 1999; 17:303-21. [PMID: 10564845 DOI: 10.1016/s0933-3657(99)00021-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
An experiment-oriented integrated model of the regulation of the biologically ubiquitous NF-kappaB and AP-1 gene transcription promoters was built by extending a previously developed qualitative process system for simulating cell behavior in the immune system. The core knowledge base (KB) implemented a deep biological ontology including molecular, ultrastructural, cytological, histological, and organismic definitions. KB states, relationships, predicates, and heuristics also represented process interactions between reactive oxygen species, growth factors, and a variety of kinases phosphorylating intermediate molecules in the NF-kappaB and AP-1 regulatory signaling pathways. The system successfully simulated the molecular process steps underlying outcomes of eight different molecular genetics laboratory experiments, including those dealing with NF-kappaB and AP-1 regulation in immunodeficiency virus infection and tumor necrosis factor responses.
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Affiliation(s)
- R B Trelease
- Department of Pathology and Laboratory Medicine, UCLA School of Medicine, Los Angeles, CA 90095, USA.
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55
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Nielsen P, Degen O, Brümmer J, Gabbe EE. Long-term survival in a patient with AIDS and hereditary haemochromatosis. Eur J Haematol 1999; 63:202-4. [PMID: 10485275 DOI: 10.1111/j.1600-0609.1999.tb01768.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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56
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Seve M, Favier A, Osman M, Hernandez D, Vaitaitis G, Flores NC, McCord JM, Flores SC. The human immunodeficiency virus-1 Tat protein increases cell proliferation, alters sensitivity to zinc chelator-induced apoptosis, and changes Sp1 DNA binding in HeLa cells. Arch Biochem Biophys 1999; 361:165-72. [PMID: 9882443 DOI: 10.1006/abbi.1998.0942] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The HIV-1 transcriptional regulatory protein Tat is a pleiotropic factor that represses expression of the human Mn-superoxide dismutase. Tat increases oxidative stress, as shown by decreased glutathione and NADPH levels. These redox changes enhance proliferation and apoptosis and alter the activity of zinc thiolate-containing proteins such as Sp1. Cells stably producing the Tat protein have an increased proliferation rate, which can be inhibited by pretreatment with the antioxidant mercaptopropionylglycine. Conversely, cells exposed to low concentrations of the oxidant paraquat are stimulated to divide. Intermediate and higher paraquat levels result in increased apoptosis or necrosis, respectively, suggesting that the physiological end point depends on the dose of oxidant used. Furthermore, treatment with the zinc chelator (N,N,N', N'-tetrakis(2-pyridylmethyl)ethylenediamine (TPEN) sensitizes HeLa-tat cells to apoptosis. In these cells, binding of the zinc-containing factor Sp1 to its DNA sequence is higher than in parental cells. Normal DNA binding is partially restored by pretreatment with a compound that mimics superoxide dismutase activity. Interestingly, Sp1-DNA interactions decrease more rapidly in the HeLa-tat cells after TPEN treatment. HeLa cell extracts incubated in the presence of purified Tat protein have increased Sp1 binding, consistent with the results observed in Tat-transfected cells. These results suggest that the Tat protein, via direct or indirect mechanisms, increases proliferation, sensitizes cells to apoptosis, and changes the conformation of Sp1, affecting its ability to bind to its cognate DNA sequence and to retain its zinc.
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Affiliation(s)
- M Seve
- Laboratoire de Biologie du Stress Oxydant (LBSO), University of Grenoble, La Tronche, 38700, France.
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57
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Grilli M, Memo M. Nuclear factor-kappaB/Rel proteins: a point of convergence of signalling pathways relevant in neuronal function and dysfunction. Biochem Pharmacol 1999; 57:1-7. [PMID: 9920279 DOI: 10.1016/s0006-2952(98)00214-7] [Citation(s) in RCA: 150] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Nuclear factor-kappaB (NF-kappaB)/Rel designates a family of transcription factors participating in the activation of a wide range of genes crucially involved in immune and inflammatory function. NF-kappaB/Rel proteins have been demonstrated recently in primary neurons and in several brain areas. Functional significance of these proteins is still not understood completely, but since certain subsets of neurons appear to contain constitutively active DNA-binding activity, it seems likely that they may participate in normal brain function. A growing body of evidence is accumulating for a specific activation of NF-kappaB/Rel proteins in the CNS, and in particular in neuronal cells, during neurodegenerative processes associated to etiologically unrelated conditions. Whether NF-kappaB activation is part of the neurodegenerative process or of protective mechanisms is a matter of debate. This issue will be reviewed here with particular attention to the available reports on the activity of NF-kappaB/Rel proteins in both experimental paradigms of neurodegeneration and post-mortem brain tissue of patients affected by various neurological diseases. We hypothesize that NF-kappaB/Rel proteins may represent the point of convergence of several signalling pathways relevant for initiating or accelerating the process of neuronal dysfunction and degeneration in many neurological diseases, including Parkinson's disease, Alzheimer's disease, CNS viral infections, and possibly others. If NF-kappaB/Rel proteins represent an integrating point of several pathways potentially contributing to neuronal degeneration, molecules that finely modulate their activity could represent a novel pharmacological approach to several neurological diseases.
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Affiliation(s)
- M Grilli
- Schering-Plough Research Institute, San Raffaele Science Park, Milan, Italy.
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58
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O'Brien-Ladner AR, Blumer BM, Wesselius LJ. Differential regulation of human alveolar macrophage-derived interleukin-1beta and tumor necrosis factor-alpha by iron. THE JOURNAL OF LABORATORY AND CLINICAL MEDICINE 1998; 132:497-506. [PMID: 9851740 DOI: 10.1016/s0022-2143(98)90128-7] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Human lungs accumulate iron with the aging process. In some circumstances associated with lung injury (eg, smoking), this acquisition of iron in lung tissue and alveolar macrophages (AMs) is escalated. We hypothesized that excess cellular iron interfered with the production of tumor necrosis factor-alpha (TNF-alpha) and interleukin-1-beta (IL-1-beta) by AMs. To examine this hypothesis, we acquired AMs from smokers and nonsmokers by bronchoalveolar lavage. AMs were stimulated by lipopolysaccharide (LPS), with and without deferoxamine (DFA), a chelator of iron. Enzyme-linked immunosorbent assay and Northern analysis were used to quantitate cytokine concentrations and mRNA. The addition of DFA increased the release of IL-1-beta, but not TNF-alpha, from AMs from smokers and nonsmokers. The DFA augmentation of LPS-induced IL-1-beta was more pronounced in smokers' AMs than in those from non-smokers (4.5-fold vs 2.6-fold increase). The addition of FeCl3 to DFA diminished the augmenting effect on the release of IL-1-beta, suggesting that the mechanism of action involved iron chelation. Conversely, as the intensity of iron chelation increased, the release of IL-1-beta and TNF-alpha decreased, as was also shown with hydroxyl radical scavenging by dimethylthiourea. This inhibition, however, occurred at very different thresholds for each cytokine. These data support a relationship between excess alveolar iron and the generation of inflammation within the lung.
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59
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60
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Richardson DR. Potential of iron chelators as effective antiproliferative agents. Can J Physiol Pharmacol 1997. [DOI: 10.1139/y97-156] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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61
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Lee R, Beauparlant P, Elford H, Ponka P, Hiscott J. Selective inhibition of l kappaB alpha phosphorylation and HIV-1 LTR-directed gene expression by novel antioxidant compounds. Virology 1997; 234:277-90. [PMID: 9268159 DOI: 10.1006/viro.1997.8642] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Oxidative stress activates the NF-kappaB/Rel transcription factors which are involved in the activation of numerous immunoregulatory genes and the human immunodeficiency virus type 1 (HIV-1) long terminal repeat (LTR). In the present study, we examined the effects of established and novel compounds including antioxidants, ribonucleotide reductase inhibitors, and iron chelators on NF-kappaB activation and HIV LTR-mediated gene expression induced by TNF-alpha. N-Acetylcysteine (NAC), pyrrolidinedithiocarbamate (PDTC), and Trimidox (TD) at various concentrations inhibited TNF-alpha-induced NF-kappaB binding in Jurkat cells. Pretreatment of cells with these compounds prior to stimulation prevented I kappaB alpha degradation. Phosphorylation of I kappaB alpha, a prerequisite for its signal-induced degradation, was abrogated in these cells, indicating that oxidative stress is an essential step in the NF-kappaB activation pathway. On the other hand, iron chelators desferrioxamine, pyridoxal isonicotinoyl hydrazone (PIH), and salicylaldehyde isonicotinoyl hydrazone (SIH) showed no inhibition of TNF-alpha-induced NF-kappaB DNA-binding activity. Synergistic induction of HIV-1 LTR-mediated gene expression by TNF-alpha and the HIV-1 transactivator Tat in Jurkat cells was significantly suppressed in the presence of NAC and TD, but not PDTC. The inhibition of NAC and TD on LTR-directed gene expression was diminished when NF-kappaB-binding sites in the LTR were deleted, indicating that these compounds affected the NF-kappaB component of the synergism. Iron chelators PIH and SIH also showed some inhibitory effect on LTR-mediated gene activation, presumably through an NF-kappaB-independent mechanism. These experiments demonstrate that TD, at concentration 50 times lower than the effective concentration of NAC, potently inhibits NF-kappaB activity and suppresses HIV LTR expression.
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Affiliation(s)
- R Lee
- Lady Davis Institute for Medical Research, Department of Microbiology, McGill University, Montreal, Quebec, Canada
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62
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Zmudzka BZ, Strickland AG, Beer JZ, Ben-Hur E. Photosensitized decontamination of blood with the silicon phthalocyanine Pc 4: no activation of the human immunodeficiency virus promoter. Photochem Photobiol 1997; 65:461-4. [PMID: 9077132 DOI: 10.1111/j.1751-1097.1997.tb08590.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Photochemical decontamination of red blood cell concentrates (RBCC) with the silicon phthalocyanine Pc 4 and red light is being studied to enhance the viral safety of blood transfusion. Recent reports indicate that treatments with radiation and various phototsensitizing agents can activate the promoter of human immunodeficiency virus (HIV). This raises the possibility that an inadequate, sublethal photochemical treatment of RBCC could induce HIV in latently infected cells. This question has been addressed using HeLa cells stably transfected with the chloramphenicol acetyl transferase gene under the control of the HIV promoter. In control studies, 8-methoxypsoralen (8-MOP) excited by UVA light caused activation of the HIV promoter in a dose- and time-dependent manner. At 0.1 microgram/mL of 8-MOP, maximal activation occurred with 18 J/cm2, 30 h after light exposure, With Pc 4 at 20 nM, over 90% of HeLa cells were killed after 24 h when exposed to 1 J/cm2 of red light. During that time interval and over a wide range of light doses no activation of the HIV promoter occurred. It is concluded that RBCC sterilization with Pc 4 and red light is unlikely to induce HIV production in latently infected cells.
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Affiliation(s)
- B Z Zmudzka
- Food and Drug Administration, Center for Devices and Radiological Health, Rockville, MD, USA
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63
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Abstract
A variety of laboratory and clinical investigations during the past 15 years have observed that one of the dangers of excessive iron is its ability to favor animal viral infections. The metal is essential for host cell synthesis of virions and can also impair defense cell function and increase oxidative stress. In both animal models and humans, viral infections cause upregulation of the iron withholding defense system. Factors that suppress the system enhance viral progression; factors that strengthen the system augment host defense. Procedures designed to reinforce the system are being developed and tested; some of these may become useful adjuncts in prevention and management of viral diseases.
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Affiliation(s)
- E D Weinberg
- Department of Biology, Indiana University, Bloomington 47405, USA
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