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Krivokrysenko VI, Toshkov IA, Gleiberman AS, Krasnov P, Shyshynova I, Bespalov I, Maitra RK, Narizhneva NV, Singh VK, Whitnall MH, Purmal AA, Shakhov AN, Gudkov AV, Feinstein E. The Toll-Like Receptor 5 Agonist Entolimod Mitigates Lethal Acute Radiation Syndrome in Non-Human Primates. PLoS One 2015; 10:e0135388. [PMID: 26367124 PMCID: PMC4569586 DOI: 10.1371/journal.pone.0135388] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2014] [Accepted: 07/15/2015] [Indexed: 12/28/2022] Open
Abstract
There are currently no approved medical radiation countermeasures (MRC) to reduce the lethality of high-dose total body ionizing irradiation expected in nuclear emergencies. An ideal MRC would be effective even when administered well after radiation exposure and would counteract the effects of irradiation on the hematopoietic system and gastrointestinal tract that contribute to its lethality. Entolimod is a Toll-like receptor 5 agonist with demonstrated radioprotective/mitigative activity in rodents and radioprotective activity in non-human primates. Here, we report data from several exploratory studies conducted in lethally irradiated non-human primates (rhesus macaques) treated with a single intramuscular injection of entolimod (in the absence of intensive individualized supportive care) administered in a mitigative regimen, 1-48 hours after irradiation. Following exposure to LD50-70/40 of radiation, injection of efficacious doses of entolimod administered as late as 25 hours thereafter reduced the risk of mortality 2-3-fold, providing a statistically significant (P<0.01) absolute survival advantage of 40-60% compared to vehicle treatment. Similar magnitude of survival improvement was also achieved with drug delivered 48 hours after irradiation. Improved survival was accompanied by predominantly significant (P<0.05) effects of entolimod administration on accelerated morphological recovery of hematopoietic and immune system organs, decreased severity and duration of thrombocytopenia, anemia and neutropenia, and increased clonogenic potential of the bone marrow compared to control irradiated animals. Entolimod treatment also led to reduced apoptosis and accelerated crypt regeneration in the gastrointestinal tract. Together, these data indicate that entolimod is a highly promising potential life-saving treatment for victims of radiation disasters.
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Affiliation(s)
| | - Ilia A. Toshkov
- Cleveland BioLabs, Inc. (CBLI), Buffalo, New York, United States of America
| | | | - Peter Krasnov
- Cleveland BioLabs, Inc. (CBLI), Buffalo, New York, United States of America
| | - Inna Shyshynova
- Cleveland BioLabs, Inc. (CBLI), Buffalo, New York, United States of America
| | - Ivan Bespalov
- Cleveland BioLabs, Inc. (CBLI), Buffalo, New York, United States of America
| | - Ratan K. Maitra
- Cleveland BioLabs, Inc. (CBLI), Buffalo, New York, United States of America
| | | | - Vijay K. Singh
- Armed Forces Radiobiology Research Institute (AFRRI), Bethesda, Maryland, United States of America
| | - Mark H. Whitnall
- Armed Forces Radiobiology Research Institute (AFRRI), Bethesda, Maryland, United States of America
| | - Andrei A. Purmal
- Cleveland BioLabs, Inc. (CBLI), Buffalo, New York, United States of America
| | | | - Andrei V. Gudkov
- Cleveland BioLabs, Inc. (CBLI), Buffalo, New York, United States of America
- Department of Cell Stress Biology, Roswell Park Cancer Institute (RPCI), Buffalo, New York, United States of America
- * E-mail: (AVG); (EF)
| | - Elena Feinstein
- Cleveland BioLabs, Inc. (CBLI), Buffalo, New York, United States of America
- * E-mail: (AVG); (EF)
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Hata K, Urushibara A, Yamashita S, Lin M, Muroya Y, Shikazono N, Yokoya A, Fu H, Katsumura Y. Chemical repair activity of free radical scavenger edaravone: reduction reactions with dGMP hydroxyl radical adducts and suppression of base lesions and AP sites on irradiated plasmid DNA. JOURNAL OF RADIATION RESEARCH 2015; 56:59-66. [PMID: 25212600 PMCID: PMC4572592 DOI: 10.1093/jrr/rru079] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/30/2014] [Revised: 08/08/2014] [Accepted: 08/16/2014] [Indexed: 06/03/2023]
Abstract
Reactions of edaravone (3-methyl-1-phenyl-2-pyrazolin-5-one) with deoxyguanosine monophosphate (dGMP) hydroxyl radical adducts were investigated by pulse radiolysis technique. Edaravone was found to reduce the dGMP hydroxyl radical adducts through electron transfer reactions. The rate constants of the reactions were greater than 4 × 10(8) dm(3) mol(-1) s(-1) and similar to those of the reactions of ascorbic acid, which is a representative antioxidant. Yields of single-strand breaks, base lesions, and abasic sites produced in pUC18 plasmid DNA by gamma ray irradiation in the presence of low concentrations (10-1000 μmol dm(-3)) of edaravone were also quantified, and the chemical repair activity of edaravone was estimated by a method recently developed by the authors. By comparing suppression efficiencies to the induction of each DNA lesion, it was found that base lesions and abasic sites were suppressed by the chemical repair activity of edaravone, although the suppression of single-strand breaks was not very effective. This phenomenon was attributed to the chemical repair activity of edaravone toward base lesions and abasic sites. However, the chemical repair activity of edaravone for base lesions was lower than that of ascorbic acid.
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Affiliation(s)
- Kuniki Hata
- Department of Nuclear Engineering and Management, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan Advanced Science Research Center, Japan Atomic Energy Agency, 2-4 Shirakatashirane, Tokai-mura, Naka-gun, Ibaraki 319-1195, Japan
| | - Ayumi Urushibara
- Laboratory of Radiation Biology, Osaka Prefecture University, 1-2 Gakuenchou, Naka-ku, Sakai-shi, Osaka 599-8570, Japan
| | - Shinichi Yamashita
- Nuclear Professional School, School of Engineering, The University of Tokyo, 2-22 Shirakatashirane, Tokai-mura, Nakagun, Ibaraki 319-1188, Japan
| | - Mingzhang Lin
- School of Nuclear Science and Technology, University of Science and Technology of China, 96 JinZhai Road, Hefei, Anhui 230026, P.R. China
| | - Yusa Muroya
- Department of Beam Materials Science, Institute of Scientific and Industrial Research, Osaka University, 8-1 Mihogaoka, Ibaraki-shi, Osaka 567-0047, Japan
| | - Naoya Shikazono
- Quantum Beam Science Directorate, Japan Atomic Energy Agency, 8-1-7 Umemidai, Kizukawa-shi, Kyoto 619-0215, Japan
| | - Akinari Yokoya
- Advanced Science Research Center, Japan Atomic Energy Agency, 2-4 Shirakatashirane, Tokai-mura, Naka-gun, Ibaraki 319-1195, Japan
| | - Haiying Fu
- Shanghai Institute of Applied Physcs, Chinese Academy of Science, Shanghai 201800, P.R. China
| | - Yosuke Katsumura
- Department of Nuclear Engineering and Management, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan Nuclear Professional School, School of Engineering, The University of Tokyo, 2-22 Shirakatashirane, Tokai-mura, Nakagun, Ibaraki 319-1188, Japan
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Hata K, Urushibara A, Yamashita S, Shikazono N, Yokoya A, Katsumura Y. Chemical repair of base lesions, AP-sites, and strand breaks on plasmid DNA in dilute aqueous solution by ascorbic acid. Biochem Biophys Res Commun 2013; 434:341-5. [DOI: 10.1016/j.bbrc.2013.03.075] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2013] [Accepted: 03/24/2013] [Indexed: 10/27/2022]
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Rathod MA, Patel D, Das A, Tipparaju SR, Shinde SS, Anderson RF. Inhibition of radical-induced DNA strand breaks by water-soluble constituents of coffee: phenolics and caffeine metabolites. Free Radic Res 2013; 47:480-7. [DOI: 10.3109/10715762.2013.788167] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Anderson RF, Harris TA. Dopamine and uric acid act as antioxidants in the repair of DNA radicals: implications in Parkinson's disease. Free Radic Res 2004; 37:1131-6. [PMID: 14703803 DOI: 10.1080/10715760310001604134] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Dopamine (DA) and uric acid (UA) have been found to undergo a protective reaction effecting the fast chemical repair of oxidative free-radical damage to DNA. This antioxidant reaction does not occur with normal concentrations of other, more abundant, antioxidants and our findings suggest that DA and UA are important for the preservation of the DNA in certain brains cells per se. These studies point to the need for drugs that undergo a similar antioxidant reaction with DNA radicals to prevent or arrest DNA damage associated with Parkinson's disease when the levels of DA and UA fall.
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Affiliation(s)
- Robert F Anderson
- Department of Auckland Cancer Society Research Centre, The University of Auckland, Private Bag 92019, Auckland 1, New Zealand.
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Ottaviani JI, Carrasquedo F, Keen CL, Lazarus SA, Schmitz HH, Fraga CG. Influence of flavan-3-ols and procyanidins on UVC-mediated formation of 8-oxo-7,8-dihydro-2'-deoxyguanosine in isolated DNA. Arch Biochem Biophys 2002; 406:203-8. [PMID: 12361708 DOI: 10.1016/s0003-9861(02)00455-1] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The flavan-3-ols (-)-epicatechin (epicatechin) and (+)-catechin (catechin) and their related oligomers (procyanidins) isolated from cocoa were assayed for their capacity to inhibit the UVC-mediated formation of 8-oxo-7,8-dihydro-2'-deoxyguanosine (oxo(8)dG) in calf thymus DNA. The above-mentioned compounds inhibited oxo(8)dG production in a concentration- and time-dependent manner. After 30 min of irradiation (30 kJ/m(2)), 0.1, 1.0, 10, and 100 microM epicatechin inhibited oxo(8)dG formation by 20, 36, 64, and 74%, respectively. For the same dose of UVC, 0.1, 1.0, 10, and 100 microM catechin inhibited oxo(8)dG formation by 1, 23, 50, and 70%, respectively. Epicatechin was more efficient than catechin with respect to inhibiting oxo(8)dG formation (IC(50) 1.7 +/- 0.7 vs 4.0 +/- 0.7 microM). Monomer, tetramer, and hexamer fractions were equally effective in inhibiting oxo(8)dG formation when assayed at 10 microM monomer equivalent concentration. At similar concentrations (1-50 microM), the inhibition of the UVC-mediated oxo(8)dG formation by flavan-3-ols and procyanidins was in the range of that of alpha-tocopherol, Trolox, ascorbate, and glutathione. These results support the concept that flavan-3-ols and their related procyanidins can protect DNA from oxidation at concentrations that can be physiologically relevant. Both epimerism and degree of oligomerization are important determinants of the antioxidant activity of flavan-3-ols and procyanidins.
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Affiliation(s)
- Javier I Ottaviani
- Fisicoquimíca-PRALIB, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Junín 956, Buenos Aires, Argentina
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