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Ling MT, Luk SU, Al-Ejeh F, Khanna KK. Tocotrienol as a potential anticancer agent. Carcinogenesis 2011; 33:233-9. [PMID: 22095072 DOI: 10.1093/carcin/bgr261] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Vitamin E is composed of two structurally similar compounds: tocopherols (TPs) and tocotrienols (T3). Despite being overshadowed by TP over the past few decades, T3 is now considered to be a promising anticancer agent due to its potent effects against a wide range of cancers. A growing body of evidence suggests that in addition to its antioxidative and pro-apoptotic functions, T3 possesses a number of anticancer properties that make it superior to TP. These include the inhibition of epithelial-to-mesenchymal transitions, the suppression of vascular endothelial growth factor tumor angiogenic pathway and the induction of antitumor immunity. More recently, T3, but not TP, has been shown to have chemosensitization and anti-cancer stem cell effects, further demonstrating the potential of T3 as an effective anticancer therapeutic agent. With most of the previous clinical studies on TP producing disappointing results, research has now focused on testing T3 as the next generation vitamin E for chemoprevention and cancer treatment. This review will summarize recent developments in the understanding of the anticancer effects of T3. We will also discuss current progress in clinical trials involving T3 as an adjuvant to conventional cancer therapy.
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Affiliation(s)
- Ming T Ling
- Australian Prostate Cancer Research Centre-Queensland, Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Queensland, Qld 4102, Australia.
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102
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Singh PK, Wise SY, Ducey EJ, Brown DS, Singh VK. Radioprotective efficacy of tocopherol succinate is mediated through granulocyte-colony stimulating factor. Cytokine 2011; 56:411-21. [DOI: 10.1016/j.cyto.2011.08.016] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2011] [Revised: 07/14/2011] [Accepted: 08/05/2011] [Indexed: 12/17/2022]
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103
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Nowak G, Bakajsova D, Hayes C, Hauer-Jensen M, Compadre CM. γ-Tocotrienol protects against mitochondrial dysfunction and renal cell death. J Pharmacol Exp Ther 2011; 340:330-8. [PMID: 22040679 DOI: 10.1124/jpet.111.186882] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Oxidative stress is a major mechanism of a variety of renal diseases. Tocopherols and tocotrienols are well known antioxidants. This study aimed to determine whether γ-tocotrienol (GT3) protects against mitochondrial dysfunction and renal proximal tubular cell (RPTC) injury caused by oxidants. Primary cultures of RPTCs were injured by using tert-butyl hydroperoxide (TBHP) in the absence and presence of GT3 or α-tocopherol (AT). Reactive oxygen species (ROS) production increased 300% in TBHP-injured RPTCs. State 3 respiration, oligomycin-sensitive respiration, and respiratory control ratio (RCR) decreased 50, 63, and 47%, respectively. The number of RPTCs with polarized mitochondria decreased 54%. F₀F₁-ATPase activity and ATP content decreased 31 and 65%, respectively. Cell lysis increased from 3% in controls to 26 and 52% at 4 and 24 h, respectively, after TBHP exposure. GT3 blocked ROS production, ameliorated decreases in state 3 and oligomycin-sensitive respirations and F₀F₁-ATPase activity, and maintained RCR and mitochondrial membrane potential (ΔΨ(m)) in injured RPTCs. GT3 maintained ATP content, blocked RPTC lysis at 4 h, and reduced it to 13% at 24 h after injury. Treatment with equivalent concentrations of AT did not block ROS production and cell lysis and moderately improved mitochondrial respiration and coupling. This is the first report demonstrating the protective effects of GT3 against RPTC injury by: 1) decreasing production of ROS, 2) improving mitochondrial respiration, coupling, ΔΨ(m), and F₀F₁-ATPase function, 3) maintaining ATP levels, and 4) preventing RPTC lysis. Our data suggest that GT3 is superior to AT in protecting RPTCs against oxidant injury and may prove therapeutically valuable for preventing renal injury associated with oxidative stress.
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Affiliation(s)
- Grazyna Nowak
- Department of Pharmaceutical Sciences, University of Arkansas for Medical Sciences, 4301 West Markham St., MS 522-3, Little Rock, AR 72205, USA.
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104
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Singh PK, Wise SY, Ducey EJ, Fatanmi OO, Elliott TB, Singh VK. α-Tocopherol succinate protects mice against radiation-induced gastrointestinal injury. Radiat Res 2011; 177:133-45. [PMID: 22013885 DOI: 10.1667/rr2627.1] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
The purpose of this study was to elucidate the role of α-tocopherol succinate (α-TS) in protecting mice from gastrointestinal syndrome induced by total-body irradiation. CD2F1 mice were injected subcutaneously with 400 mg/kg of α-TS and exposed to different doses of (60)Co γ radiation, and 30-day survival was monitored. Jejunum sections were analyzed for crypts and villi, PUMA (p53 upregulated modulator of apoptosis), and apoptosis (terminal deoxynucleotidyl transferase dUTP nick end labeling - TUNEL). The crypt regeneration in irradiated mice was evaluated by 5-bromo-2-deoxyuridine (BrdU). Bacterial translocation from gut to heart, spleen and liver in α-TS-treated and irradiated mice was evaluated by bacterial culture on sheep blood agar, colistin-nalidixic acid, and xylose-lysine-desoxycholate medium. Our results demonstrate that α-TS enhanced survival in a significant number of mice irradiated with 9.5, 10, 11 and 11.5 Gy (60)Co γ radiation when administered 24 h before radiation exposure. α-TS also protected the intestinal tissue of irradiated mice in terms of crypt and villus number, villus length and mitotic figures. TS treatment decreased the number of TUNEL- and PUMA-positive cells and increased the number of BrdU-positive cells in jejunum compared to vehicle-treated mice. Further, α-TS inhibited gut bacterial translocation to the heart, spleen and liver in irradiated mice. Our data suggest that α-TS protects mice from radiation-induced gastrointestinal damage by inhibiting apoptosis, promoting regeneration of crypt cells, and inhibiting translocation of gut bacteria.
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Affiliation(s)
- Pankaj K Singh
- Radiation Countermeasures Program, Armed Forces Radiobiology Research Institute, 8901 Wisconsin Ave, Bethesda, MD 20889-5603, USA.
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105
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Singh VK, Singh PK, Wise SY, Seed TM. Mobilized progenitor cells as a bridging therapy for radiation casualties: A brief review of tocopherol succinate-based approaches. Int Immunopharmacol 2011; 11:842-47. [DOI: 10.1016/j.intimp.2011.01.017] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2010] [Revised: 01/18/2011] [Accepted: 01/19/2011] [Indexed: 12/11/2022]
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106
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Wilankar C, Sharma D, Checker R, Khan NM, Patwardhan R, Patil A, Sandur SK, Devasagayam TPA. Role of immunoregulatory transcription factors in differential immunomodulatory effects of tocotrienols. Free Radic Biol Med 2011; 51:129-43. [PMID: 21536125 DOI: 10.1016/j.freeradbiomed.2011.03.038] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/12/2010] [Revised: 03/01/2011] [Accepted: 03/28/2011] [Indexed: 12/20/2022]
Abstract
Tocotrienols have been shown to possess antioxidant, antitumor, cardioprotective, and antiproliferative effects. This report describes novel immunomodulatory effects of tocotrienols in murine lymphocytes. γ-Tocotrienol (GT) was more effective in suppressing concanavalin A (Con A)-induced T cell proliferation and cytokine production compared to α-tocotrienol (AT) when present continuously in the culture. GT inhibited T cell activation markers and costimulatory molecule. GT modulated intracellular glutathione in lymphocytes, and the suppressive effects of GT could not be abrogated by thiol or nonthiol antioxidants, indicating a poor link between anti-inflammatory properties of tocotrienols and cellular redox status. It was also observed that GT suppressed Con A-induced activation of NF-κB, AP-1, and NF-κB-dependent gene expression. Cellular uptake studies with tocotrienols showed higher accumulation of GT compared to AT. Similar immunosuppressive effects of GT were also observed when administered to mice. In contrast, transient exposure of lymphocytes to GT (4 h) resulted in higher survival and proliferation of lymphocytes in vitro and in vivo in syngeneic and allogeneic hosts. This was attributed to the ability of GT to induce NF-κB, AP-1, and mTOR activation in lymphocytes upon transient exposure. Our results demonstrated that antioxidants such as tocotrienols may exhibit pleiotropic effects by activating multiple mechanisms in cells.
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Affiliation(s)
- Chandan Wilankar
- Radiation Biology & Health Sciences Division, Bhabha Atomic Research Centre, Mumbai 400085, India
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107
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Satyamitra MM, Kulkarni S, Ghosh SP, Mullaney CP, Condliffe D, Srinivasan V. Hematopoietic Recovery and Amelioration of Radiation-Induced Lethality by the Vitamin E Isoform δ-Tocotrienol. Radiat Res 2011; 175:736-45. [DOI: 10.1667/rr2460.1] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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108
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Satyamitra M, Lombardini E, Graves J, Mullaney C, Ney P, Hunter J, Johnson K, Tamburini P, Wang Y, Springhorn JP, Srinivasan V. A TPO Receptor Agonist, ALXN4100TPO, Mitigates Radiation-Induced Lethality and Stimulates Hematopoiesis in CD2F1 Mice. Radiat Res 2011; 175:746-58. [DOI: 10.1667/rr2462.1] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- Merriline Satyamitra
- Armed Forces Radiobiology Research Institute (AFRRI), Uniformed Services University, Bethesda, Maryland 20889
| | - Eric Lombardini
- Armed Forces Radiobiology Research Institute (AFRRI), Uniformed Services University, Bethesda, Maryland 20889
| | - John Graves
- Armed Forces Radiobiology Research Institute (AFRRI), Uniformed Services University, Bethesda, Maryland 20889
| | - Conor Mullaney
- Armed Forces Radiobiology Research Institute (AFRRI), Uniformed Services University, Bethesda, Maryland 20889
| | - Patrick Ney
- Armed Forces Radiobiology Research Institute (AFRRI), Uniformed Services University, Bethesda, Maryland 20889
| | - Jeffrey Hunter
- Alexion Pharmaceuticals, Inc., 352 Knotter Drive, Cheshire, Connecticut 06410
| | - Krista Johnson
- Alexion Pharmaceuticals, Inc., 352 Knotter Drive, Cheshire, Connecticut 06410
| | - Paul Tamburini
- Alexion Pharmaceuticals, Inc., 352 Knotter Drive, Cheshire, Connecticut 06410
| | - Yi Wang
- Alexion Pharmaceuticals, Inc., 352 Knotter Drive, Cheshire, Connecticut 06410
| | | | - Venkataraman Srinivasan
- Armed Forces Radiobiology Research Institute (AFRRI), Uniformed Services University, Bethesda, Maryland 20889
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109
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Berbee M, Fu Q, Boerma M, Pathak R, Zhou D, Kumar KS, Hauer-Jensen M. Reduction of radiation-induced vascular nitrosative stress by the vitamin E analog γ-tocotrienol: evidence of a role for tetrahydrobiopterin. Int J Radiat Oncol Biol Phys 2011; 79:884-91. [PMID: 20950957 PMCID: PMC3023840 DOI: 10.1016/j.ijrobp.2010.08.032] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2010] [Revised: 08/19/2010] [Accepted: 08/20/2010] [Indexed: 01/13/2023]
Abstract
PURPOSE The vitamin E analog γ-tocotrienol (GT3) is a powerful radioprotector. GT3 reduces postradiation vascular peroxynitrite production, an effect dependent on inhibition of hydroxy-methylglutaryl-coenzyme A reductase. Hydroxy-methylglutaryl-coenzyme A reductase inhibitors mediate their pleiotropic effects via endothelial nitric oxide synthase that requires the cofactor tetrahydrobiopterin (BH4). This study investigated the effects of radiation on BH4 bioavailability and of GT3 on BH4 metabolism. METHODS AND MATERIALS Mice were exposed to 8.5 Gy of total body irradiation (TBI). Lung BH4 and total biopterin concentrations were measured 0, 3.5, 7, 14, and 21 days after TBI by use of differential oxidation followed by high-performance liquid chromatography. The effect of exogenous GT3 and BH4 treatment on postradiation vascular oxidative stress and bone marrow colony-forming units were assessed in vivo. The effect of GT3 on endothelial cell apoptosis and endothelial expression of guanosine triphosphate (GTP) cyclohydrolase 1 (GTPCH), GTPCH feedback regulatory protein (GFRP), GFRP transcription, GFRP protein levels, and GFRP-GTPCH protein binding was determined in vitro. RESULTS Compared with baseline levels, lung BH4 concentrations decreased by 24% at 3.5 days after TBI, an effect that was reversed by GT3. At 14 and 21 days after TBI, compensatory increases in BH4 (58% and 80%, respectively) were observed. Relative to vehicle-treated controls, both GT3 and BH4 supplementation reduced postirradiation vascular peroxynitrite production at 3.5 days (by 66% and 33%, respectively), and BH4 resulted in a 68% increase in bone marrow colony-forming units. GT3 ameliorated endothelial cell apoptosis and reduced endothelial GFRP protein levels and GFRP-GTPCH binding by decreasing transcription of the GFRP gene. CONCLUSIONS BH4 bioavailability is reduced in the early postradiation phase. Exogenous administration of BH4 reduces postirradiation vascular oxidative stress. GT3 potently reduces the expression of GFRP, one of the key regulatory proteins in the BH4 pathway, and may thus exert some of its beneficial effects on postradiation free radical production partly by counteracting the decrease in BH4.
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Affiliation(s)
- Maaike Berbee
- University of Arkansas for Medical Sciences, Little Rock, AR
| | - Qiang Fu
- University of Arkansas for Medical Sciences, Little Rock, AR
| | - Marjan Boerma
- University of Arkansas for Medical Sciences, Little Rock, AR
| | - Rupak Pathak
- University of Arkansas for Medical Sciences, Little Rock, AR
| | - Daohong Zhou
- University of Arkansas for Medical Sciences, Little Rock, AR
| | - K. Sree Kumar
- Armed Forces Radiobiology Research Institute, Uniformed Services University of the Health Sciences, Bethesda, MD
| | - Martin Hauer-Jensen
- University of Arkansas for Medical Sciences, Little Rock, AR
- Central Arkansas Veterans Healthcare System, Little Rock, AR
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Berbée M, Fu Q, Garg S, Kulkarni S, Kumar KS, Hauer-Jensen M. Pentoxifylline enhances the radioprotective properties of γ-tocotrienol: differential effects on the hematopoietic, gastrointestinal and vascular systems. Radiat Res 2010; 175:297-306. [PMID: 21388273 DOI: 10.1667/rr2399.1] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The vitamin E analog γ-tocotrienol (GT3) is a potent radioprotector and mitigator. This study was performed to (a) determine whether the efficacy of GT3 can be enhanced by the addition of the phosphodiesterase inhibitor pentoxifylline (PTX) and (b) to obtain information about the mechanism of action. Mice were injected subcutaneously with vehicle, GT3 [400 mg/kg 24 h before total-body irradiation (TBI)], PTX (200 mg/kg 30 min before TBI), or GT3+PTX before being exposed to 8.5-13 Gy TBI. Overall lethality, survival time and intestinal, hematopoietic and vascular injury were assessed. Cytokine levels in the bone marrow microenvironment were measured, and the requirement for endothelial nitric oxide synthase (eNOS) was studied in eNOS-deficient mice. GT3+PTX significantly improved survival compared to GT3 alone and provided full protection against lethality even after exposure to 12.5 Gy. GT3+PTX improved bone marrow CFUs, spleen colony counts and platelet recovery compared to GT3 alone. GT3 and GT3+PTX increased bone marrow plasma G-CSF levels as well as the availability of IL-1α, IL-6 and IL-9 in the early postirradiation phase. GT3 and GT3+PTX were equally effective in ameliorating intestinal injury and vascular peroxynitrite production. Survival studies in eNOS-deficient mice and appropriate controls revealed that eNOS was not required for protection against lethality after TBI. Combined treatment with GT3 and PTX increased postirradiation survival over that with GT3 alone by a mechanism that may depend on induction of hematopoietic stimuli. GT3+PTX did not reduce GI toxicity or vascular oxidative stress compared to GT3 alone. The radioprotective effect of either drug alone or both drugs in combination does not require the presence of eNOS.
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Affiliation(s)
- Maaike Berbée
- Division of Radiation Health, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205, USA
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111
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Kulkarni S, Ghosh SP, Satyamitra M, Mog S, Hieber K, Romanyukha L, Gambles K, Toles R, Kao TC, Hauer-Jensen M, Kumar KS. Gamma-Tocotrienol Protects Hematopoietic Stem and Progenitor Cells in Mice after Total-Body Irradiation. Radiat Res 2010; 173:738-47. [DOI: 10.1667/rr1824.1] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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112
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Brown AP, Chung EJ, Urick ME, Shield WP, Sowers AL, Thetford A, Shankavaram UT, Mitchell JB, Citrin DE. Evaluation of the fullerene compound DF-1 as a radiation protector. Radiat Oncol 2010; 5:34. [PMID: 20459795 PMCID: PMC2877563 DOI: 10.1186/1748-717x-5-34] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2010] [Accepted: 05/11/2010] [Indexed: 01/21/2023] Open
Abstract
Background Fullerene compounds are known to possess antioxidant properties, a common property of chemical radioprotectors. DF-1 is a dendrofullerene nanoparticle with antioxidant properties previously found to be radioprotective in a zebrafish model. The purpose of this study was to evaluate the radioprotective effects of DF-1 in a murine model of lethal total body irradiation and to assess for selective radioprotection of normal cells versus tumor cells. Methods In vitro radioresponse was evaluated with clonogenic assays with human tumor cells and fibroblast lines in the presence of varying concentrations of DF-1 or vehicle. DNA double strand break induction and repair was evaluated with immunocytochemistry for γH2AX. Lethal total body irradiation was delivered with 137Cs after intraperitoneal delivery of DF-1 or vehicle control. Bone marrow hypoxia was evaluated with piminidazole uptake assessed by flow cytometry. Results DF-1 provided modest radioprotection of human cancer cell lines and fibroblast cell lines when delivered prior to irradiation (dose modifying factor or 1.1). There was no evidence of selective protection of fibroblasts versus tumor cells. Cells treated with DF-1 at radioprotective doses were found to have fewer γH2AX foci at 1 and 6 hours after irradiation compared to vehicle treated controls. The LD50/30 for C57Bl6/Ncr mice treated with a single 300 mg/kg dose of DF-1 pre-irradiation was 10.09 Gy (95% CI 9.58-10.26) versus 8.29 Gy (95% CI, 8.21-8.32) for control mice. No protective effects were seen with a single 200 mg/kg dose. No increase in pimonidazole uptake was appreciated in bone marrow of mice treated with DF-1 compared to vehicle controls. Conclusions DF-1 has modest activity as a radiation protector in vivo. There was no evidence of selective protection from irradiation of normal versus tumor cells with DF-1.
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Affiliation(s)
- Aaron P Brown
- Radiation Oncology Branch, National Cancer Institute, Building 10 CRC/B2-3500, Bethesda, MD 20892, USA
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Abstract
IMPORTANCE OF THE FIELD Ionizing radiation (IR) can produce deleterious effects in living tissues, leading to significant morbidity and a potentially fatal illness affecting various organs dose-dependently. As people may be exposed to IR during cancer radiotherapy or as a result of a radiological/nuclear incident or act of terrorism, the danger of irradiation represents a serious public health problem. At present, however, this problem remains largely impervious to medical management. There is, therefore, a pressing need to develop safe and effective radiation countermeasure (RC) agents to prevent, mitigate or treat the harmful consequences of IR exposure. AREAS COVERED IN THIS REVIEW Recent advances in the search for RC agents as reflected by the relevant patent literature of the past five years along with peer-reviewed publications are surveyed. WHAT THE READER WILL GAIN A total of 43 patents, describing approximately 38 chemically diverse compounds with RC potential are analyzed. These include antioxidants capable of scavenging IR-induced free radicals, modulators of cell death signaling or cell cycle progression, cytokines or growth factors promoting tissue repair and inhibitors of inflammatory cytokines. TAKE HOME MESSAGE Several of these RC candidates appear promising, including at least two that are undergoing evaluation for fast-track clinical development.
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Affiliation(s)
- Francis Dumont
- Université de Strasbourg, Centre Régional de Lutte contre le Cancer Paul Strauss, Laboratoire de Radiobiologie EA-3430, 3 rue de la Porte de l'Hôpital, F-67065 Strasbourg, France
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114
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Preclinical development of a bridging therapy for radiation casualties. Exp Hematol 2010; 38:61-70. [DOI: 10.1016/j.exphem.2009.10.008] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2009] [Revised: 10/11/2009] [Accepted: 10/15/2009] [Indexed: 01/31/2023]
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115
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Tocopherol succinate: A promising radiation countermeasure. Int Immunopharmacol 2009; 9:1423-30. [DOI: 10.1016/j.intimp.2009.08.020] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2009] [Revised: 08/10/2009] [Accepted: 08/20/2009] [Indexed: 11/23/2022]
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