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Approaches to the design of catalytic metallodrugs. Curr Opin Chem Biol 2015; 25:172-83. [PMID: 25765750 DOI: 10.1016/j.cbpa.2015.01.024] [Citation(s) in RCA: 110] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2015] [Accepted: 01/26/2015] [Indexed: 01/10/2023]
Abstract
Metal ions are known to act as catalytic centres in metallo-enzymes. On the other hand, low-molecular-weight metal complexes are widely used as catalysts in chemical systems. However, small catalysts do not have a large protein ligand to provide substrate selectivity and minimize catalyst poisoning. Despite the challenges that the lack of a protein ligand might pose, some success in the use of metal catalysts for biochemical transformations has been reported. Here, we present a brief overview of such reports, especially involving catalytic reactions in cells. Examples include C-C bond formation, deprotection and functional group modification, degradation of biomolecules, and redox modulation. We discuss four classes of catalytic redox modulators: photosensitizers, superoxide dismutase mimics, thiol oxidants, and transfer hydrogenation catalysts. Catalytic metallodrugs offer the prospect of low-dose therapy and a challenging new design strategy for future exploration.
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Apostolova N, Victor VM. Molecular strategies for targeting antioxidants to mitochondria: therapeutic implications. Antioxid Redox Signal 2015; 22:686-729. [PMID: 25546574 PMCID: PMC4350006 DOI: 10.1089/ars.2014.5952] [Citation(s) in RCA: 180] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Mitochondrial function and specifically its implication in cellular redox/oxidative balance is fundamental in controlling the life and death of cells, and has been implicated in a wide range of human pathologies. In this context, mitochondrial therapeutics, particularly those involving mitochondria-targeted antioxidants, have attracted increasing interest as potentially effective therapies for several human diseases. For the past 10 years, great progress has been made in the development and functional testing of molecules that specifically target mitochondria, and there has been special focus on compounds with antioxidant properties. In this review, we will discuss several such strategies, including molecules conjugated with lipophilic cations (e.g., triphenylphosphonium) or rhodamine, conjugates of plant alkaloids, amino-acid- and peptide-based compounds, and liposomes. This area has several major challenges that need to be confronted. Apart from antioxidants and other redox active molecules, current research aims at developing compounds that are capable of modulating other mitochondria-controlled processes, such as apoptosis and autophagy. Multiple chemically different molecular strategies have been developed as delivery tools that offer broad opportunities for mitochondrial manipulation. Additional studies, and particularly in vivo approaches under physiologically relevant conditions, are necessary to confirm the clinical usefulness of these molecules.
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Affiliation(s)
- Nadezda Apostolova
- 1 Faculty of Health Sciences, University Jaume I , Castellón de la Plana, Spain
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Slosky LM, Vanderah TW. Therapeutic potential of peroxynitrite decomposition catalysts: a patent review. Expert Opin Ther Pat 2015; 25:443-66. [PMID: 25576197 DOI: 10.1517/13543776.2014.1000862] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
INTRODUCTION Peroxynitrite is a cytotoxic oxidant species implicated in a host of pathologies, including inflammatory and neurodegenerative diseases, cancer, radiation injury and chronic pain. With the recognition of the role of peroxynitrite in disease, numerous experimental and therapeutic tools have arisen to probe peroxyntirite's pathophysiological contribution and attenuate its oxidative damage. Peroxynitrite decomposition catalysts (PNDCs) are redox-active compounds that detoxify peroxynitrite by catalyzing its isomerization or reduction to nitrate or nitrite. AREAS COVERED This review discusses recent research articles and patents published 1995 - 2014 on the development and therapeutic use of PNDCs. Iron and manganese metalloporphyrin PNDCs attenuate the toxic effects of peroxynitrite and are currently being developed for clinical applications. Additionally, some Mn porphyrin-based PNDCs have optimized pharmaceutical properties such that they exhibit greater peroxynitrite selectivity. Other classes of PNDC agents, including bis(hydroxyphenyl)dipyrromethenes and metallocorroles, have demonstrated preclinical efficacy, oral availability and reduced toxicity risk. EXPERT OPINION Interest in the drug-like properties of peroxynitrite-neutralizing agents has grown with the realization that PNDCs will be powerful tools in the treatment of disease. The design of compounds with enhanced oral availability and peroxynitrite selectivity is a critical step toward the availability of safe, effective and selective redox modulators for the treatment of peroxynitrite-associated pathologies.
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Affiliation(s)
- Lauren M Slosky
- University of Arizona, Department of Pharmacology , Life Science North Rm 621, 1501 North Campbell Ave., Tucson, AZ 85721 , USA
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Haber A, Gross Z. Catalytic antioxidant therapy by metallodrugs: lessons from metallocorroles. Chem Commun (Camb) 2015; 51:5812-27. [DOI: 10.1039/c4cc08715a] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
This article provides a perspective on the utility of metal-based catalytic antioxidants for disease prevention or treatment, with focus on their mode of action and its dependence (DCA) or independence (ICA) on the involvement of cofactors.
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Affiliation(s)
- Adi Haber
- Schulich Faculty of Chemistry
- Technion – Israel Institute of Technology
- Technion City
- Israel
| | - Zeev Gross
- Schulich Faculty of Chemistry
- Technion – Israel Institute of Technology
- Technion City
- Israel
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Tovmasyan A, Carballal S, Ghazaryan R, Melikyan L, Weitner T, Maia CC, Reboucas JS, Radi R, Spasojevic I, Benov L, Batinic-Haberle I. Rational design of superoxide dismutase (SOD) mimics: the evaluation of the therapeutic potential of new cationic Mn porphyrins with linear and cyclic substituents. Inorg Chem 2014; 53:11467-83. [PMID: 25333724 PMCID: PMC4220860 DOI: 10.1021/ic501329p] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2014] [Indexed: 02/06/2023]
Abstract
Our goal herein has been to gain further insight into the parameters which control porphyrin therapeutic potential. Mn porphyrins (MnTnOct-2-PyP(5+), MnTnHexOE-2-PyP(5+), MnTE-2-PyPhP(5+), and MnTPhE-2-PyP(5+)) that bear the same positive charge and same number of carbon atoms at meso positions of porphyrin core were explored. The carbon atoms of their meso substituents are organized to form either linear or cyclic structures of vastly different redox properties, bulkiness, and lipophilicities. These Mn porphyrins were compared to frequently studied compounds, MnTE-2-PyP(5+), MnTE-3-PyP(5+), and MnTBAP(3-). All Mn(III) porphyrins (MnPs) have metal-centered reduction potential, E1/2 for Mn(III)P/Mn(II)P redox couple, ranging from -194 to +340 mV versus NHE, log kcat(O2(•-)) from 3.16 to 7.92, and log kred(ONOO(-)) from 5.02 to 7.53. The lipophilicity, expressed as partition between n-octanol and water, log POW, was in the range -1.67 to -7.67. The therapeutic potential of MnPs was assessed via: (i) in vitro ability to prevent spontaneous lipid peroxidation in rat brain homogenate as assessed by malondialdehyde levels; (ii) in vivo O2(•-) specific assay to measure the efficacy in protecting the aerobic growth of SOD-deficient Saccharomyces cerevisiae; and (iii) aqueous solution chemistry to measure the reactivity toward major in vivo endogenous antioxidant, ascorbate. Under the conditions of lipid peroxidation assay, the transport across the cellular membranes, and in turn shape and size of molecule, played no significant role. Those MnPs of E1/2 ∼ +300 mV were the most efficacious, significantly inhibiting lipid peroxidation in 0.5-10 μM range. At up to 200 μM, MnTBAP(3-) (E1/2 = -194 mV vs NHE) failed to inhibit lipid peroxidation, while MnTE-2-PyPhP(5+) with 129 mV more positive E1/2 (-65 mV vs NHE) was fully efficacious at 50 μM. The E1/2 of Mn(III)P/Mn(II)P redox couple is proportional to the log kcat(O2(•-)), i.e., the SOD-like activity of MnPs. It is further proportional to kred(ONOO(-)) and the ability of MnPs to prevent lipid peroxidation. In turn, the inhibition of lipid peroxidation by MnPs is also proportional to their SOD-like activity. In an in vivo S. cerevisiae assay, however, while E1/2 predominates, lipophilicity significantly affects the efficacy of MnPs. MnPs of similar log POW and E1/2, that have linear alkyl or alkoxyalkyl pyridyl substituents, distribute more easily within a cell and in turn provide higher protection to S. cerevisiae in comparison to MnP with bulky cyclic substituents. The bell-shape curve, with MnTE-2-PyP(5+) exhibiting the highest ability to catalyze ascorbate oxidation, has been established and discussed. Our data support the notion that the SOD-like activity of MnPs parallels their therapeutic potential, though species other than O2(•-), such as peroxynitrite, H2O2, lipid reactive species, and cellular reductants, may be involved in their mode(s) of action(s).
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Affiliation(s)
- Artak Tovmasyan
- Departments of Radiation Oncology and Medicine, Duke University Medical Center, Research Drive, 281b MSRB I, Durham, North Carolina 27710, United States
| | - Sebastian Carballal
- Departamento
de Bioquímica and Center for Free Radical and Biomedical
Research, Facultad de Medicina, Universidad
de la República, Montevideo, Uruguay
| | - Robert Ghazaryan
- Department of Organic Chemistry, Faculty
of Pharmacy, Yerevan State Medical University, Yerevan, Armenia
| | - Lida Melikyan
- Department of Organic Chemistry, Faculty
of Pharmacy, Yerevan State Medical University, Yerevan, Armenia
| | - Tin Weitner
- Departments of Radiation Oncology and Medicine, Duke University Medical Center, Research Drive, 281b MSRB I, Durham, North Carolina 27710, United States
| | - Clarissa
G. C. Maia
- Departamento de Quimica, CCEN, Universidade
Federal de Paraiba, Joao Pessoa, PB 58051-900, Brazil
| | - Julio S. Reboucas
- Departamento de Quimica, CCEN, Universidade
Federal de Paraiba, Joao Pessoa, PB 58051-900, Brazil
| | - Rafael Radi
- Departamento
de Bioquímica and Center for Free Radical and Biomedical
Research, Facultad de Medicina, Universidad
de la República, Montevideo, Uruguay
| | - Ivan Spasojevic
- Departments of Radiation Oncology and Medicine, Duke University Medical Center, Research Drive, 281b MSRB I, Durham, North Carolina 27710, United States
| | - Ludmil Benov
- Department of Biochemistry, Faculty of Medicine, Kuwait University, Kuwait City, Kuwait
| | - Ines Batinic-Haberle
- Departments of Radiation Oncology and Medicine, Duke University Medical Center, Research Drive, 281b MSRB I, Durham, North Carolina 27710, United States
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Medhora M, Gao F, Wu Q, Molthen RC, Jacobs ER, Moulder JE, Fish BL. Model development and use of ACE inhibitors for preclinical mitigation of radiation-induced injury to multiple organs. Radiat Res 2014; 182:545-55. [PMID: 25361399 DOI: 10.1667/rr13425.1] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
The NIH/NIAID initiated a countermeasure program to develop mitigators for radiation-induced injuries from a radiological attack or nuclear accident. We have previously characterized and demonstrated mitigation of single organ injuries, such as radiation pneumonitis, pulmonary fibrosis or nephropathy by angiotensin converting enzyme (ACE) inhibitors. Our current work extends this research to examine the potential for mitigating multiple organ dysfunctions occurring in the same irradiated rats. Using total body irradiation (TBI) followed by bone marrow transplant, we tested four doses of X radiation (11, 11.25, 11.5 and 12 Gy) to develop lethal late effects. We identified three of these doses (11, 11.25 and 11.5 Gy TBI) that were lethal to all irradiated rats by 160 days to test mitigation by ACE inhibitors of injury to the lungs and kidneys. In this study we tested three ACE inhibitors at doses: captopril (88 and 176 mg/m(2)/day), enalapril (18, 24 and 36 mg/m(2)/day) and fosinopril (60 mg/m(2)/day) for mitigation. Our primary end point was survival or criteria for euthanization of morbid animals. Secondary end points included breathing intervals, other assays for lung structure and function and blood urea nitrogen (BUN) to assess renal damage. We found that captopril at 176 mg/m(2)/day increased survival after 11 or 11.5 Gy TBI. Enalapril at 18-36 mg/m(2)/day improved survival at all three doses (TBI). Fosinopril at 60 mg/m(2)/day enhanced survival at a dose of 11 Gy, although no improvement was observed for pneumonitis. These results demonstrate the use of a single countermeasure to mitigate the lethal late effects in the same animal after TBI.
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Weitzel DH, Tovmasyan A, Ashcraft KA, Rajic Z, Weitner T, Liu C, Li W, Buckley AF, Prasad MR, Young KH, Rodriguiz RM, Wetsel WC, Peters KB, Spasojevic I, Herndon JE, Batinic-Haberle I, Dewhirst MW. Radioprotection of the brain white matter by Mn(III) n-Butoxyethylpyridylporphyrin-based superoxide dismutase mimic MnTnBuOE-2-PyP5+. Mol Cancer Ther 2014; 14:70-9. [PMID: 25319393 DOI: 10.1158/1535-7163.mct-14-0343] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Cranial irradiation is a standard therapy for primary and metastatic brain tumors. A major drawback of radiotherapy (RT), however, is long-term cognitive loss that affects quality of life. Radiation-induced oxidative stress in normal brain tissue is thought to contribute to cognitive decline. We evaluated the effectiveness of a novel mimic of superoxide dismutase enzyme (SOD), MnTnBuOE-2-PyP(5+)(Mn(III) meso-tetrakis(N-n-butoxyethylpyridinium-2-yl)porphyrin), to provide long-term neuroprotection following 8 Gy of whole brain irradiation. Long-term RT damage can only be assessed by brain imaging and neurocognitive studies. C57BL/6J mice were treated with MnTnBuOE-2-PyP(5+) before and after RT and evaluated three months later. At this time point, drug concentration in the brain was 25 nmol/L. Mice treated with MnTnBuOE-2-PyP(5+)/RT exhibited MRI evidence for myelin preservation in the corpus callosum compared with saline/RT treatment. Corpus callosum histology demonstrated a significant loss of axons in the saline/RT group that was rescued in the MnTnBuOE-2-PyP(5+)/RT group. In addition, the saline/RT groups exhibited deficits in motor proficiency as assessed by the rotorod test and running wheel tests. These deficits were ameliorated in groups treated with MnTnBuOE-2-PyP(5+)/RT. Our data demonstrate that MnTnBuOE-2-PyP(5+) is neuroprotective for oxidative stress damage caused by radiation exposure. In addition, glioblastoma cells were not protected by MnTnBuOE-2-PyP(5+) combination with radiation in vitro. Likewise, the combination of MnTnBuOE-2-PyP(5+) with radiation inhibited tumor growth more than RT alone in flank tumors. In summary, MnTnBuOE-2-PyP(5+) has dual activity as a neuroprotector and a tumor radiosensitizer. Thus, it is an attractive candidate for adjuvant therapy with RT in future studies with patients with brain cancer.
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Affiliation(s)
- Douglas H Weitzel
- Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina
| | - Artak Tovmasyan
- Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina
| | - Kathleen A Ashcraft
- Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina
| | - Zrinka Rajic
- Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina
| | - Tin Weitner
- Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina
| | - Chunlei Liu
- Brain Imaging and Analysis Center, Duke University Medical Center, Durham, North Carolina
| | - Wei Li
- Brain Imaging and Analysis Center, Duke University Medical Center, Durham, North Carolina
| | - Anne F Buckley
- Department of Pathology, Duke University Medical Center, Durham, North Carolina. Preston Robert Tisch Brain Tumor Center, Duke University Medical Center, Durham, North Carolina. Animal Pathology Core, Duke University Medical Center, Durham, North Carolina
| | - Mark R Prasad
- Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina
| | - Kenneth H Young
- Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina
| | - Ramona M Rodriguiz
- Department of Psychiatry and Behavioral Sciences, Duke University Medical Center, Durham, North Carolina
| | - William C Wetsel
- Department of Psychiatry and Behavioral Sciences, Duke University Medical Center, Durham, North Carolina. Department of Neurobiology and Cell Biology, Duke University Medical Center, Durham, North Carolina
| | - Katherine B Peters
- Medicine and Duke Cancer Institute, Duke University Medical Center, Durham, North Carolina
| | - Ivan Spasojevic
- PK/PD BioAnalytical DCI Shared Resource, Duke University Medical Center, Durham, North Carolina
| | - James E Herndon
- Biostatistics and Bioinformatics, Duke University Medical Center, Durham, North Carolina
| | - Ines Batinic-Haberle
- Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina
| | - Mark W Dewhirst
- Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina. Preston Robert Tisch Brain Tumor Center, Duke University Medical Center, Durham, North Carolina.
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Celic T, Španjol J, Bobinac M, Tovmasyan A, Vukelic I, Reboucas JS, Batinic-Haberle I, Bobinac D. Mn porphyrin-based SOD mimic, MnTnHex-2-PyP(5+), and non-SOD mimic, MnTBAP(3-), suppressed rat spinal cord ischemia/reperfusion injury via NF-κB pathways. Free Radic Res 2014; 48:1426-42. [PMID: 25185063 DOI: 10.3109/10715762.2014.960865] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Herein we have demonstrated that both superoxide dismutase (SOD) mimic, cationic Mn(III) meso-tetrakis(N-n-hexylpyridinium-2-yl)porphyrin (MnTnHex-2-PyP(5+)), and non-SOD mimic, anionic Mn(III) meso-tetrakis(4-carboxylatophenyl)porphyrin (MnTBAP(3-)), protect against oxidative stress caused by spinal cord ischemia/reperfusion via suppression of nuclear factor kappa B (NF-κB) pro-inflammatory pathways. Earlier reports showed that Mn(III) N-alkylpyridylporphyrins were able to prevent the DNA binding of NF-κB in an aqueous system, whereas MnTBAP(3-) was not. Here, for the first time, in a complex in vivo system-animal model of spinal cord injury-a similar impact of MnTBAP(3-), at a dose identical to that of MnTnHex-2-PyP(5+), was demonstrated in NF-κB downregulation. Rats were treated subcutaneously at 1.5 mg/kg starting at 30 min before ischemia/reperfusion, and then every 12 h afterward for either 48 h or 7 days. The anti-inflammatory effects of both Mn porphyrins (MnPs) were demonstrated in the spinal cord tissue at both 48 h and 7 days. The downregulation of NF-κB, a major pro-inflammatory signaling protein regulating astrocyte activation, was detected and found to correlate well with the suppression of astrogliosis (as glial fibrillary acidic protein) by both MnPs. The markers of oxidative stress, lipid peroxidation and protein carbonyl formation, were significantly reduced by MnPs. The favorable impact of both MnPs on motor neurons (Tarlov score and inclined plane test) was assessed. No major changes in glutathione peroxidase- and SOD-like activities were demonstrated, which implies that none of the MnPs acted as SOD mimic. Increasing amount of data on the reactivity of MnTBAP(3-) with reactive nitrogen species (RNS) (.NO/HNO/ONOO(-)) suggests that RNS/MnTBAP(3-)-driven modification of NF-κB protein cysteines may be involved in its therapeutic effects. This differs from the therapeutic efficacy of MnTnHex-2-PyP(5+) which presumably occurs via reactive oxygen species and relates to NF-κB thiol oxidation; the role of RNS cannot be excluded.
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Affiliation(s)
- T Celic
- Department of Anatomy, Faculty of Medicine, University of Rijeka , Rijeka , Croatia
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59
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Li AM, Martins J, Tovmasyan A, Valentine JS, Batinic-Haberle I, Spasojevic I, Gralla EB. Differential localization and potency of manganese porphyrin superoxide dismutase-mimicking compounds in Saccharomyces cerevisiae. Redox Biol 2014; 3:1-6. [PMID: 25462059 PMCID: PMC4299968 DOI: 10.1016/j.redox.2014.09.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2014] [Revised: 09/14/2014] [Accepted: 09/15/2014] [Indexed: 11/04/2022] Open
Abstract
Cationic Mn(III) porphyrin complexes based on MnTM-2-PyP are among the most promising superoxide dismutase (SOD) mimicking compounds being considered as potential anti-inflammatory drugs. We studied four of these active compounds in the yeast Saccharomyces cerevisiae, MnTM-2-PyP, MnTE-2-PyP, MnTnHex-2-PyP, and MnTnBu-2-PyP, each of which differs only in the length of its alkyl substituents. Each was active in improving the aerobic growth of yeast lacking SOD (sod1∆) in complete medium, and the efficacy of each mimic was correlated with its characteristic catalytic activity. We also studied the partitioning of these compounds between mitochondria and cytosol and found that the more hydrophobic members of the series accumulated in the mitochondria. Moreover, the degree to which a mimic mitigated the sod1Δ auxotrophic phenotype for lysine relative to its auxotrophic phenotype for methionine depended upon its level of lipophilicity-dependent accumulation inside the mitochondria. We conclude that localization within the cell is an important factor in biological efficacy in addition to the degree of catalytic activity, and we discuss possible explanations for this effect. Cellular distribution of Mn porphyrin SOD mimics correlates with their lipophilicity. Higher lipophilicity directs Mn porphyrin SOD mimics to the mitochondria. In sod1∆ yeast, SOD mimics in mitochondria increased rescue of Lys, not Met auxotrophy. A mitochondrial target is involved in the sod1∆-dependent Lys auxotrophy.
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Affiliation(s)
- Alice Ma Li
- Department of Chemistry and Biochemistry, UCLA, 607 Charles E Young Drive East, Los Angeles, CA 90095-1569, USA
| | - Jake Martins
- Department of Chemistry and Biochemistry, UCLA, 607 Charles E Young Drive East, Los Angeles, CA 90095-1569, USA
| | - Artak Tovmasyan
- Department of Radiation Oncology, Duke University Medical Center, NC 27710, USA
| | - Joan S Valentine
- Department of Chemistry and Biochemistry, UCLA, 607 Charles E Young Drive East, Los Angeles, CA 90095-1569, USA
| | | | - Ivan Spasojevic
- Department of Medicine and PK/PD Shared Resource of Duke Cancer Institute, Duke University Medical Center, NC 27710, USA
| | - Edith B Gralla
- Department of Chemistry and Biochemistry, UCLA, 607 Charles E Young Drive East, Los Angeles, CA 90095-1569, USA.
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Novel amphiphilic cationic porphyrin and its Ag(II) complex as potential anticancer agents. J Inorg Biochem 2014; 140:94-103. [PMID: 25086237 DOI: 10.1016/j.jinorgbio.2014.06.013] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2013] [Revised: 06/18/2014] [Accepted: 06/18/2014] [Indexed: 11/23/2022]
Abstract
In the present study we have synthesized a novel amphiphilic porphyrin and its Ag(II) complex through modification of water-soluble porphyrinic structure in order to increase its lipophilicity and in turn pharmacological potency. New cationic non-symmetrical meso-substituted porphyrins were characterized by UV-visible, electrospray ionization mass spectrometry (ESI-MS), (1)H NMR techniques, lipophilicity (thin-layer chromatographic retention factor, Rf), and elemental analysis. The key toxicological profile (i.e. cytotoxicity and cell line- (cancer type-) specificity; genotoxicity; cell cycle effects) of amphiphilic Ag porphyrin was studied in human normal and cancer cell lines of various tissue origins and compared with its water-soluble analog. Structural modification of the molecule from water-soluble to amphiphilic resulted in a certain increase in the cytotoxicity and a decrease in cell line-specificity. Importantly, Ag(II) porphyrin showed less toxicity to normal cells and greater toxicity to their cancerous counterparts as compared to cisplatin. The amphiphilic complex was also not genotoxic and demonstrated a slight cytostatic effect via the cell cycle delay due to the prolongation of S-phase. As expected, the performed structural modification affected also the photocytotoxic activity of metal-free amphiphilic porphyrin. The ligand tested on cancer cell line revealed a dramatic (more than 70-fold) amplification of its phototoxic activity as compared to its water-soluble tetracationic metal-free analog. The compound combines low dark cytotoxicity with 5 fold stronger phototoxicity relative to Chlorin e6 and could be considered as a potential photosensitizer for further development in photodynamic therapy.
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61
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Sheng H, Chaparro RE, Sasaki T, Izutsu M, Pearlstein RD, Tovmasyan A, Warner DS. Metalloporphyrins as therapeutic catalytic oxidoreductants in central nervous system disorders. Antioxid Redox Signal 2014; 20:2437-64. [PMID: 23706004 DOI: 10.1089/ars.2013.5413] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
SIGNIFICANCE Metalloporphyrins, characterized by a redox-active transitional metal (Mn or Fe) coordinated to a cyclic porphyrin core ligand, mitigate oxidative/nitrosative stress in biological systems. Side-chain substitutions tune redox properties of metalloporphyrins to act as potent superoxide dismutase mimics, peroxynitrite decomposition catalysts, and redox regulators of transcription factor function. With oxidative/nitrosative stress central to pathogenesis of CNS injury, metalloporphyrins offer unique pharmacologic activity to improve the course of disease. RECENT ADVANCES Metalloporphyrins are efficacious in models of amyotrophic lateral sclerosis, Alzheimer's disease, epilepsy, neuropathic pain, opioid tolerance, Parkinson's disease, spinal cord injury, and stroke and have proved to be useful tools in defining roles of superoxide, nitric oxide, and peroxynitrite in disease progression. The most substantive recent advance has been the synthesis of lipophilic metalloporphyrins offering improved blood-brain barrier penetration to allow intravenous, subcutaneous, or oral treatment. CRITICAL ISSUES Insufficient preclinical data have accumulated to enable clinical development of metalloporphyrins for any single indication. An improved definition of mechanisms of action will facilitate preclinical modeling to define and validate optimal dosing strategies to enable appropriate clinical trial design. Due to previous failures of "antioxidants" in clinical trials, with most having markedly less biologic activity and bioavailability than current-generation metalloporphyrins, a stigma against antioxidants has discouraged the development of metalloporphyrins as CNS therapeutics, despite the consistent definition of efficacy in a wide array of CNS disorders. FUTURE DIRECTIONS Further definition of the metalloporphyrin mechanism of action, side-by-side comparison with "failed" antioxidants, and intense effort to optimize therapeutic dosing strategies are required to inform and encourage clinical trial design.
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Affiliation(s)
- Huaxin Sheng
- 1 Department of Anesthesiology, Duke University Medical Center (DUMC) , Durham, North Carolina
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62
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Delmastro-Greenwood MM, Tse HM, Piganelli JD. Effects of metalloporphyrins on reducing inflammation and autoimmunity. Antioxid Redox Signal 2014; 20:2465-77. [PMID: 23472672 DOI: 10.1089/ars.2013.5257] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
SIGNIFICANCE High levels of reactive oxygen species can facilitate DNA and protein damage beyond the control of endogenous antioxidants, resulting in oxidative stress. Oxidative stress then triggers inflammation, which can lead to pathological conditions. In genetically susceptible individuals, the conglomeration of oxidative stress and inflammation can enhance autoreactive immune cell activation, causing beta-cell destruction in autoimmune type 1 diabetes. As a means of shielding pancreatic islets, manganese porphyrin (MnP) oxidoreductant treatment has been tested in a number of reported studies. RECENT ADVANCES MnP affects both innate and adaptive immune cell responses, blocking nuclear factor kappa-B activation, proinflammatory cytokine secretion, and T helper 1 T-cell responses. As a result, MnP treatment protects against type 1 diabetes onset in nonobese diabetic mice and stabilizes islets for cellular transplantation. CRITICAL ISSUES MnP displays global immunosuppressive properties, exemplified by decreased cytokine production from all T-helper cell subsets. This quality may impact infection control in the setting of autoimmunity. Nonetheless, because of their cytoprotective and immunomodulatory function, MnPs should be considered as a safer alternative to other clinical immunosuppressive agents (i.e., rapamycin) for transplantation. FUTURE DIRECTIONS Although MnP likely affects only redox-sensitive targets, the mechanism behind global T-cell immunosuppression and the outcome on infection clearance will have to be elucidated. Based on the increased primary engraftment seen with MnP use, protection against primary nonfunction in porcine to human xenotransplants would likely be enhanced. Further, a better understanding of MnP oxidoreductase function may allow for its use in other chronic inflammatory conditions.
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Affiliation(s)
- Meghan M Delmastro-Greenwood
- 1 Division of Immunogenetics, Department of Pediatrics, Rangos Research Center, Diabetes Institute , Children's Hospital of Pittsburgh of UPMC, Pittsburgh, Pennsylvania
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Tovmasyan A, Reboucas JS, Benov L. Simple biological systems for assessing the activity of superoxide dismutase mimics. Antioxid Redox Signal 2014; 20:2416-36. [PMID: 23964890 PMCID: PMC4005499 DOI: 10.1089/ars.2013.5576] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
SIGNIFICANCE Half a century of research provided unambiguous proof that superoxide and species derived from it-reactive oxygen species (ROS)-play a central role in many diseases and degenerative processes. This stimulated the search for pharmaceutical agents that are capable of preventing oxidative damage, and methods of assessing their therapeutic potential. RECENT ADVANCES The limitations of superoxide dismutase (SOD) as a therapeutic tool directed attention to small molecules, SOD mimics, that are capable of catalytically scavenging superoxide. Several groups of compounds, based on either metal complexes, including metalloporphyrins, metallocorroles, Mn(II) cyclic polyamines, and Mn(III) salen derivatives, or non-metal based compounds, such as fullerenes, nitrones, and nitroxides, have been developed and studied in vitro and in vivo. Very few entered clinical trials. CRITICAL ISSUES AND FUTURE DIRECTIONS Development of SOD mimics requires in-depth understanding of their mechanisms of biological action. Elucidation of both molecular features, essential for efficient ROS-scavenging in vivo, and factors limiting the potential side effects requires biologically relevant and, at the same time, relatively simple testing systems. This review discuses the advantages and limitations of genetically engineered SOD-deficient unicellular organisms, Escherichia coli and Saccharomyces cerevisiae as tools for investigating the efficacy and mechanisms of biological actions of SOD mimics. These simple systems allow the scrutiny of the minimal requirements for a functional SOD mimic: the association of a high catalytic activity for superoxide dismutation, low toxicity, and an efficient cellular uptake/biodistribution.
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Affiliation(s)
- Artak Tovmasyan
- 1 Department of Radiation Oncology, Duke University Medical Center , Durham, North Carolina
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Batinic-Haberle I, Tovmasyan A, Roberts ERH, Vujaskovic Z, Leong KW, Spasojevic I. SOD therapeutics: latest insights into their structure-activity relationships and impact on the cellular redox-based signaling pathways. Antioxid Redox Signal 2014; 20:2372-415. [PMID: 23875805 PMCID: PMC4005498 DOI: 10.1089/ars.2012.5147] [Citation(s) in RCA: 169] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/02/2013] [Revised: 06/30/2013] [Accepted: 07/22/2013] [Indexed: 01/23/2023]
Abstract
SIGNIFICANCE Superoxide dismutase (SOD) enzymes are indispensable and ubiquitous antioxidant defenses maintaining the steady-state levels of O2·(-); no wonder, thus, that their mimics are remarkably efficacious in essentially any animal model of oxidative stress injuries thus far explored. RECENT ADVANCES Structure-activity relationship (half-wave reduction potential [E1/2] versus log kcat), originally reported for Mn porphyrins (MnPs), is valid for any other class of SOD mimics, as it is dominated by the superoxide reduction and oxidation potential. The biocompatible E1/2 of ∼+300 mV versus normal hydrogen electrode (NHE) allows powerful SOD mimics as mild oxidants and antioxidants (alike O2·(-)) to readily traffic electrons among reactive species and signaling proteins, serving as fine mediators of redox-based signaling pathways. Based on similar thermodynamics, both SOD enzymes and their mimics undergo similar reactions, however, due to vastly different sterics, with different rate constants. CRITICAL ISSUES Although log kcat(O2·(-)) is a good measure of therapeutic potential of SOD mimics, discussions of their in vivo mechanisms of actions remain mostly of speculative character. Most recently, the therapeutic and mechanistic relevance of oxidation of ascorbate and glutathionylation and oxidation of protein thiols by MnP-based SOD mimics and subsequent inactivation of nuclear factor κB has been substantiated in rescuing normal and killing cancer cells. Interaction of MnPs with thiols seems to be, at least in part, involved in up-regulation of endogenous antioxidative defenses, leading to the healing of diseased cells. FUTURE DIRECTIONS Mechanistic explorations of single and combined therapeutic strategies, along with studies of bioavailability and translational aspects, will comprise future work in optimizing redox-active drugs.
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Affiliation(s)
- Ines Batinic-Haberle
- Department of Radiation Oncology, Duke University Medical School, Durham, North Carolina
| | - Artak Tovmasyan
- Department of Radiation Oncology, Duke University Medical School, Durham, North Carolina
| | - Emily R. H. Roberts
- Department of Biomedical Engineering, Duke University, Durham, North Carolina
| | - Zeljko Vujaskovic
- Department of Radiation Oncology, Duke University Medical School, Durham, North Carolina
| | - Kam W. Leong
- Department of Biomedical Engineering, Duke University, Durham, North Carolina
- King Abdulaziz University, Jeddah, Saudi Arabia Kingdom
| | - Ivan Spasojevic
- Department of Medicine, Duke University Medical School, Durham, North Carolina
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65
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Hitomi Y, Ekawa T, Kodera M. Water Proton Relaxivity, Superoxide Dismutase-like Activity, and Cytotoxicity of a Manganese(III) Porphyrin Having Four Poly(ethylene glycol) Tails. CHEM LETT 2014. [DOI: 10.1246/cl.140029] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Yutaka Hitomi
- Department of Applied Chemistry, Graduate School of Science and Engineering, Doshisha University
| | - Tomoyuki Ekawa
- Department of Applied Chemistry, Graduate School of Science and Engineering, Doshisha University
| | - Masahito Kodera
- Department of Applied Chemistry, Graduate School of Science and Engineering, Doshisha University
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Evans MK, Tovmasyan A, Batinic-Haberle I, Devi GR. Mn porphyrin in combination with ascorbate acts as a pro-oxidant and mediates caspase-independent cancer cell death. Free Radic Biol Med 2014; 68:302-14. [PMID: 24334253 PMCID: PMC4404036 DOI: 10.1016/j.freeradbiomed.2013.11.031] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/17/2012] [Revised: 11/01/2013] [Accepted: 11/06/2013] [Indexed: 01/13/2023]
Abstract
Resistance to therapy-mediated apoptosis in inflammatory breast cancer, an aggressive and distinct subtype of breast cancer, was recently attributed to increased superoxide dismutase (SOD) expression, glutathione (GSH) content, and decreased accumulation of reactive species. In this study, we demonstrate the unique ability of two Mn(III) N-substituted pyridylporphyrin (MnP)-based SOD mimics (MnTE-2-PyP(5+) and MnTnBuOE-2-PyP(5+)) to catalyze oxidation of ascorbate, leading to the production of excessive levels of peroxide, and in turn cell death. The accumulation of peroxide, as a consequence of MnP+ascorbate treatment, was fully reversed by the administration of exogenous catalase, showing that hydrogen peroxide is essential for cell death. Cell death as a consequence of the action of MnP+ascorbate corresponded to decreases in GSH levels, prosurvival signaling (p-NF-κB, p-ERK1/2), and in expression of X-linked inhibitor of apoptosis protein, the most potent caspase inhibitor. Although markers of classical apoptosis were observed, including PARP cleavage and annexin V staining, administration of a pan-caspase inhibitor, Q-VD-OPh, did not reverse the observed cytotoxicity. MnP+ascorbate-treated cells showed nuclear translocation of apoptosis-inducing factor, suggesting the possibility of a mechanism of caspase-independent cell death. Pharmacological ascorbate has already shown promise in recently completed phase I clinical trials, in which its oxidation and subsequent peroxide formation was catalyzed by endogenous metalloproteins. The catalysis of ascorbate oxidation by an optimized metal-based catalyst (such as MnP) carries a large therapeutic potential as an anticancer agent by itself or in combination with other modalities such as radio- and chemotherapy.
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Affiliation(s)
- Myron K Evans
- Department of Surgery, Duke University Medical Center, Durham, NC 27710, USA; Department of Pathology, Duke University Medical Center, Durham, NC 27710, USA
| | - Artak Tovmasyan
- Department of Radiation Oncology, Duke University Medical Center, Durham, NC 27710, USA
| | - Ines Batinic-Haberle
- Department of Radiation Oncology, Duke University Medical Center, Durham, NC 27710, USA; Duke Cancer Institute, Duke University Medical Center, Durham, NC 27710, USA.
| | - Gayathri R Devi
- Department of Surgery, Duke University Medical Center, Durham, NC 27710, USA; Department of Pathology, Duke University Medical Center, Durham, NC 27710, USA; Duke Cancer Institute, Duke University Medical Center, Durham, NC 27710, USA.
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Gauter-Fleckenstein B, Reboucas JS, Fleckenstein K, Tovmasyan A, Owzar K, Jiang C, Batinic-Haberle I, Vujaskovic Z. Robust rat pulmonary radioprotection by a lipophilic Mn N-alkylpyridylporphyrin, MnTnHex-2-PyP(5+). Redox Biol 2014; 2:400-10. [PMID: 24624330 PMCID: PMC3949096 DOI: 10.1016/j.redox.2013.12.017] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2013] [Revised: 12/19/2013] [Accepted: 12/20/2013] [Indexed: 12/21/2022] Open
Abstract
With the goal to enhance the distribution of cationic Mn porphyrins within mitochondria, the lipophilic Mn(III)meso-tetrakis(N-n-hexylpyridinium-2-yl)porphyrin, MnTnHex-2-PyP(5+) has been synthesized and tested in several different model of diseases, where it shows remarkable efficacy at as low as 50 µg/kg single or multiple doses. Yet, in a rat lung radioprotection study, at higher 0.6-1 mg/kg doses, due to its high accumulation and micellar character, it became toxic. To avoid the toxicity, herein the pulmonary radioprotection of MnTnHex-2-PyP(5+) was assessed at 50 µg/kg. Fischer rats were irradiated to their right hemithorax (28 Gy) and treated with 0.05 mg/kg/day of MnTnHex-2-PyP(5+) for 2 weeks by subcutaneously-implanted osmotic pumps, starting at 2 h post-radiation. The body weights and breathing frequencies were followed for 10 weeks post-radiation, when the histopathology and immunohistochemistry were assessed. Impact of MnTnHex-2-PyP(5+) on macrophage recruitment (ED-1), DNA oxidative damage (8-OHdG), TGF-β1, VEGF(A) and HIF-1α were measured. MnTnHex-2-PyP(5+) significantly decreased radiation-induced lung histopathological (H&E staining) and functional damage (breathing frequencies), suppressed oxidative stress directly (8-OHdG), or indirectly, affecting TGF-β1, VEGF (A) and HIF-1α pathways. The magnitude of the therapeutic effects is similar to the effects demonstrated under same experimental conditions with 120-fold higher dose of ~5000-fold less lipophilic Mn(III)meso-tetrakis(N-ethylpyridinium-2-yl)porphyrin, MnTE-2-PyP(5+).
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Key Words
- 8-OHdG, 8-hydroxy-2'-deoxyguanosine
- AKT, protein kinase B (PKB), a serine/threonine-specific protein kinase
- ALS, amyotrophic laterial sclerosis
- AP-1, activator protein-1
- AT, ataxia telangiectasia
- BBB, blood brain barrier
- Breathing frequencies
- CNS, central nervous system
- CO3−, carbonate radical
- ClO−, hypochlorite
- ETC, mitochondrial electron transport chain
- Fischer rats
- GMP, good manufacturing practice
- GS−, monodeprotonated glutathione
- HIF-1α, hypoxia inducible factor-1
- HO2−, monodeprotonated hydrogen peroxide
- Histopathology
- I/R, ischemia reperfusion
- Immunohistochemistry
- Lung injury
- MCAO, middle cerebral artery occlusion
- Manganese porphyrins
- MnP, Mn porphyrin
- MnTDE-2-ImP5+, Mn(III) tetrakis[N,N'-diethylimidazolium-2-yl)porphyrin, AEOL10150
- MnTE-2-PyP5+
- MnTE-2-PyP5+, Mn(III) meso-tetrakis(N-ethylpyridinium-2-yl)porphyrin (AEOL10113)
- MnTnBuOE-2-PyP5+, Mn(III) meso-tetrakis(N-(n-butoxyethyl)pyridinium-2-yl)porphyrin
- MnTnHex-2-PyP5+
- MnTnHex-2-PyP5+, Mn(III) meso-tetrakis(N-(n-hexyl)pyridinium-2-yl)porphyrin (AEOL10113)
- NF-κB, nuclear factor κB
- NHE, normal hydrogen electrode
- NO, nitric oxide
- NOX4, NADPH oxidase, isoform 4 E1/2, Half-wave metal-centered reduction potential
- Nrf-2, nuclear factor-erythroid-derived 2-like 2
- O2−, superoxide
- ONOO−, peroxynitrite
- PI3K, phosphatidylinositide 3-kinase
- PTEN, phosphoinositide 3-phosphatase
- Radioprotection
- Redox-modulators
- SAH, subarachnoid hemorrhage
- SOD, superoxide dismutase
- SP-1, specificity protein-1
- TF, transcription factor
- TGF-β1, one of the 3 members of the TGF-β transforming growth factor-β family
- VEGF, vascular endothelial growth factor
- mTOR, mammalian target of rapamycin (mTOR), a serine/threonine protein kinase
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Affiliation(s)
- Benjamin Gauter-Fleckenstein
- Department of Radiation Oncology, Duke University School of Medicine, Durham, NC 27710, USA ; Department of Radiation Oncology, Universitätsmedizin Mannheim, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Julio S Reboucas
- Department of Radiation Oncology, Duke University School of Medicine, Durham, NC 27710, USA
| | - Katharina Fleckenstein
- Department of Radiation Oncology, Duke University School of Medicine, Durham, NC 27710, USA ; Department of Radiation Oncology, Universitätsmedizin Mannheim, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Artak Tovmasyan
- Department of Radiation Oncology, Duke University School of Medicine, Durham, NC 27710, USA
| | - Kouros Owzar
- Department of Biostatistics and Bioinformatics, Duke University Medical Center, Durham, USA ; Biostatistics and Computational Biology Core, RadCCORE, Duke University Medical Center, Durham, USA
| | - Chen Jiang
- Biostatistics and Computational Biology Core, RadCCORE, Duke University Medical Center, Durham, USA
| | - Ines Batinic-Haberle
- Department of Radiation Oncology, Duke University School of Medicine, Durham, NC 27710, USA
| | - Zeljko Vujaskovic
- Department of Radiation Oncology, Duke University School of Medicine, Durham, NC 27710, USA ; Division of Translational Radiation Sciences, Department of Radiation Oncology, University of Maryland, 655W Baltimore Street, Bressler Research Building, 8-025, Baltimore, MD 21201, USA
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68
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Archambeau JO, Tovmasyan A, Pearlstein RD, Crapo JD, Batinic-Haberle I. Superoxide dismutase mimic, MnTE-2-PyP(5+) ameliorates acute and chronic proctitis following focal proton irradiation of the rat rectum. Redox Biol 2013; 1:599-607. [PMID: 24363995 PMCID: PMC3863774 DOI: 10.1016/j.redox.2013.10.002] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2013] [Revised: 10/12/2013] [Accepted: 10/14/2013] [Indexed: 01/05/2023] Open
Abstract
Radiation proctitis, an inflammation and damage to the lower part of colon, is a common adverse event of the radiotherapy of tumors in the abdominal and pelvic region (colon, prostate, cervical). Several Mn(III) porphyrin-based superoxide dismutase mimics have been synthesized and successfully evaluated in preclinical models as radioprotectants. Here we report for the first time the remarkable rectal radioprotection of frequently explored Mn(III) meso-tetrakis(N-ethylpyridinium-2-yl)porphyrin, MnTE-2-PyP(5+). A batch prepared in compliance with good manufacturing practice (GMP), which has good safety/toxicity profile, was used for this study. MnTE-2-PyP(5+) was given subcutaneously at 5 mg/kg, either 1 h before or 1 h after irradiation, with additional drug administered at weekly intervals thereafter. MnTE-2-PyP(5+) ameliorated both acute and chronic radiation proctitis in male Sprague-Dawley rats irradiated with 20-30 Gy protons delivered to 2.5 cm span of rectum using spread-out Bragg peak of a proton treatment beam. Focal irradiation of the rectum produced acute proctitis, which healed, followed by chronic rectal dilation and symptomatic proctitis. MnTE-2-PyP(5+) protected rectal mucosa from radiation-induced crypt loss measured 10 days post-irradiation. Significant effects were observed with both pre- and post-treatment regimens. However, only MnTE-2-PyP(5+) pre-treatment, but not post-treatment, prevented the development of rectal dilation, indicating that proper dosing regimen is critical for radioprotection. The pre-treatment also prevented or delayed the development of chronic proctitis depending on the radiation dose. Further work aimed at developing MnTE-2-PyP(5+) and similar drugs as adjunctive agents for radiotherapy of pelvic tumors is warranted. The present study substantiates the prospects of employing this and similar analogs in preserving normal tissue during cancer radiation as well as any other radiation exposure.
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Key Words
- AP-1, activator protein-1
- CGE, cobalt gray equivalent
- GSH, glutathione
- HIF-1α, hypoxia inducible factor-1
- Mn porphyrin
- MnP, Mn(III) porphyrins
- MnTDE-2-ImP5+, Mn(III) meso-tetrakis(N,N’-diethylimidazolium-2-yl)porphyrin (AEOL10150)
- MnTE-2-PyP5+
- MnTE-2-PyP5+, Mn(III) meso-tetrakis(N-ethylpyridinium-2-yl)porphyrin (AEOL10113, BMX-010)
- MnTM-2-PyP5+, Mn(III) meso-tetrakis(N-methylpyridinium-2-yl)porphyrin (AEOL10112)
- MnTnBuOE-2-PyP5+, Mn(III) meso-tetrakis(N-n-butoxyethylpyridinium-2-yl)porphyrin
- MnTnHex-2-PyP5+, Mn(III) meso-tetrakis(N-n-hexylpyridinium-2-yl)porphyrin (BMX-001)
- NF-κB, nuclear factor κB
- PT, proton therapy
- Proton beam therapy
- Radiation proctitis
- Radioprotector
- SOD mimic
- SOD, superoxide dismutase
- SP-1, specificity protein-1
- TF, transcription factor
- kcat(O2−), the rate constant for the catalysis of O2− dismutation by Mn porphyrin or SOD enzyme
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Affiliation(s)
- John O Archambeau
- Department of Radiation Medicine, Loma Linda University, Loma Linda, CA, USA
| | - Artak Tovmasyan
- Department of Radiation Oncology, Duke University School of Medicine, Durham, NC 27710, USA
| | - Robert D Pearlstein
- Department of Surgery (Neurosurgery), Duke University School of Medicine, Durham, NC 27710, USA
| | - James D Crapo
- Department of Medicine, Division of Pulmonary, Critical Care and Sleep Medicine, Denver, CO 80206, USA
| | - Ines Batinic-Haberle
- Department of Radiation Oncology, Duke University School of Medicine, Durham, NC 27710, USA
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Weitner T, Kos I, Mandić Z, Batinić-Haberle I, Biruš M. Acid-base and electrochemical properties of manganese meso(ortho- and meta-N-ethylpyridyl)porphyrins: voltammetric and chronocoulometric study of protolytic and redox equilibria. Dalton Trans 2013; 42:14757-65. [PMID: 23933742 PMCID: PMC3876927 DOI: 10.1039/c3dt50767j] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Growing interest in redox-active compounds as therapeutics for oxidative stress-related diseases led to the design of metalloporphyrins as some of the most potent functional SOD-mimics. Herein we report a detailed electrochemical study of the protolytic and redox equilibria of manganese ortho and meta substituted N-ethylpyridyl porphyrins (MnPs), MnTE-2-PyP(5+) and MnTE-3-PyP(5+), in aqueous solutions. The electrochemical parameters of redox processes for all experimentally available species have been determined, as well as their diffusion coefficients and estimated sizes of aqueous cavities. The results indicate that possible changes of the intracellular acidity cannot affect the antioxidant activity of MnPs in vivo, since no change in the E(Mn(III)P/Mn(II)P) values was observed below pH 10. Furthermore, the results confirm that both of these MnPs can be efficient redox scavengers of peroxynitrite (ONOO(-)), another major damaging species in vivo. This can occur by either single-electron reduction or two-electron reduction of ONOO(-), involving either the Mn(IV)P/Mn(III)P redox couple or Mn(IV)P/Mn(II)P redox couple. In addition to kred(ONOO(-)) reported previously, the thermodynamic parameters calculated herein imply a strong and identical driving force for the reaction of both ortho and meta isomeric MnPs with ONOO(-). An enlargement of both Mn(III)P complexes upon an increase of the solution pH was also observed and attributed to the reduction of positive charge on the central ion caused by deprotonation of the axial water molecules. This expansion of aqueous cavities suggests the formation of a solvent cage and the increased lipophilicity of Mn(III)P complexes caused by increased electron density on the Mn ion.
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Affiliation(s)
- Tin Weitner
- University of Zagreb, Faculty of Pharmacy and Biochemistry, Ante Kovačića 1, Zagreb 10000, Croatia.
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Liochev SI. Superoxide dismutase mimics, other mimics, antioxidants, prooxidants, and related matters. Chem Res Toxicol 2013; 26:1312-9. [PMID: 23905839 DOI: 10.1021/tx4001623] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A significant number of low molecular weight metal complexes as well as metal-free compounds that are capable of scavenging superoxide and/or other radicals and reactive species in simple systems have been proposed to be used as potential drugs in the case of various diseases and/or as antiaging agents. Some have been used or suggested to be used as diagnostic tools for the involvement of such species in biological processes. In the present work, analysis of such claims indicates that their use as specific detectors of superoxide or of other reactive oxygen species is unsupported and might be confusing. Many of these compounds exert beneficial effects by counteracting the toxic effects of oxidative stress in a significant number of models of pathological processes. However, it is concluded that these actions are more likely due to other effects including prooxidant actions and that their beneficial effects also may be exerted in pathological processes that do not practically involve reactive oxygen species. Adaptation may be a common mode of action explaining a sizable portion of the beneficial effect of the so-called mimics and other compounds including prooxidants.
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Tovmasyan A, Weitner T, Sheng H, Lu M, Rajic Z, Warner DS, Spasojevic I, Reboucas JS, Benov L, Batinic-Haberle I. Differential coordination demands in Fe versus Mn water-soluble cationic metalloporphyrins translate into remarkably different aqueous redox chemistry and biology. Inorg Chem 2013; 52:5677-91. [PMID: 23646875 DOI: 10.1021/ic3012519] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The different biological behavior of cationic Fe and Mn pyridylporphyrins in Escherichia coli and mouse studies prompted us to revisit and compare their chemistry. For that purpose, the series of ortho and meta isomers of Fe(III) meso-tetrakis-N-alkylpyridylporphyrins, alkyl being methyl to n-octyl, were synthesized and characterized by elemental analysis, UV/vis spectroscopy, mass spectrometry, lipophilicity, protonation equilibria of axial waters, metal-centered reduction potential, E(1/2) for M(III)P/M(II)P redox couple (M = Fe, Mn, P = porphyrin), kcat for the catalysis of O2(•-) dismutation, stability toward peroxide-driven porphyrin oxidative degradation (produced in the catalysis of ascorbate oxidation by MP), ability to affect growth of SOD-deficient E. coli, and toxicity to mice. Electron-deficiency of the metal site is modulated by the porphyrin ligand, which renders Fe(III) porphyrins ≥5 orders of magnitude more acidic than the analogous Mn(III) porphyrins, as revealed by the pKa1 of axially coordinated waters. The 5 log units difference in the acidity between the Mn and Fe sites in porphyrin translates into the predominance of tetracationic (OH)(H2O)FeP complexes relative to pentacationic (H2O)2MnP species at pH ∼7.8. This is additionally evidenced in large differences in the E(1/2) values of M(III)P/M(II)P redox couples. The presence of hydroxo ligand labilizes trans-axial water which results in higher reactivity of Fe relative to Mn center. The differences in the catalysis of O2(•-) dismutation (log kcat) between Fe and Mn porphyrins is modest, 2.5-5-fold, due to predominantly outer-sphere, with partial inner-sphere character of two reaction steps. However, the rate constant for the inner-sphere H2O2-based porphyrin oxidative degradation is 18-fold larger for (OH)(H2O)FeP than for (H2O)2MnP. The in vivo consequences of the differences between the Fe and Mn porphyrins were best demonstrated in SOD-deficient E. coli growth. On the basis of fairly similar log kcat(O2(•-)) values, a very similar effect on the growth of SOD-deficient E. coli was anticipated by both metalloporphyrins. Yet, while (H2O)2MnTE-2-PyP(5+) was fully efficacious at ≥20 μM, the Fe analogue (OH)(H2O)FeTE-2-PyP(4+) supported SOD-deficient E. coli growth at as much as 200-fold lower doses in the range of 0.1-1 μM. Moreover the pattern of SOD-deficient E. coli growth was different with Mn and Fe porphyrins. Such results suggested a different mode of action of these metalloporphyrins. Further exploration demonstrated that (1) 0.1 μM (OH)(H2O)FeTE-2-PyP(4+) provided similar growth stimulation as the 0.1 μM Fe salt, while the 20 μM Mn salt provides no protection to E. coli; and (2) 1 μM Fe porphyrin is fully degraded by 12 h in E. coli cytosol and growth medium, while Mn porphyrin is not. Stimulation of the aerobic growth of SOD-deficient E. coli by the Fe porphyrin is therefore due to iron acquisition. Our data suggest that in vivo, redox-driven degradation of Fe porphyrins resulting in Fe release plays a major role in their biological action. Possibly, iron reconstitutes enzymes bearing [4Fe-4S] clusters as active sites. Under the same experimental conditions, (OH)(H2O)FePs do not cause mouse arterial hypotension, whereas (H2O)2MnPs do, which greatly limits the application of Mn porphyrins in vivo.
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Affiliation(s)
- Artak Tovmasyan
- Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina 27710, United States
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Weitner T, Kos I, Sheng H, Tovmasyan A, Reboucas JS, Fan P, Warner DS, Vujaskovic Z, Batinic-Haberle I, Spasojevic I. Comprehensive pharmacokinetic studies and oral bioavailability of two Mn porphyrin-based SOD mimics, MnTE-2-PyP5+ and MnTnHex-2-PyP5+. Free Radic Biol Med 2013; 58:73-80. [PMID: 23328731 PMCID: PMC3763724 DOI: 10.1016/j.freeradbiomed.2013.01.006] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/26/2012] [Revised: 12/20/2012] [Accepted: 01/03/2013] [Indexed: 10/27/2022]
Abstract
The cationic, ortho Mn(III) N-alkylpyridylporphyrins (alkyl=ethyl, E, and n-hexyl, nHex) MnTE-2-PyP(5+) (AEOL10113, FBC-007) and MnTnHex-2-PyP(5+) have proven efficacious in numerous in vivo animal models of diseases having oxidative stress in common. The remarkable therapeutic efficacy observed is due to their: (1) ability to catalytically remove O2(•-) and ONOO(-) and other reactive species; (2) ability to modulate redox-based signaling pathways; (3) accumulation within critical cellular compartments, i.e., mitochondria; and (4) ability to cross the blood-brain barrier. The similar redox activities of both compounds are related to the similar electronic and electrostatic environments around the metal active sites, whereas their different bioavailabilities are presumably influenced by the differences in lipophilicity, bulkiness, and shape. Both porphyrins are water soluble, but MnTnHex-2-PyP(5+) is approximately 4 orders of magnitude more lipophilic than MnTE-2-PyP(5+), which should positively affect its ability to pass through biological membranes, making it more efficacious in vivo at lower doses. To gain insight into the in vivo tissue distribution of Mn porphyrins and its impact upon their therapeutic efficacy and mechanistic aspects of action, as well as to provide data that would ensure proper dosing regimens, we conducted comprehensive pharmacokinetic (PK) studies for 24h after single-dose drug administration. The porphyrins were administered intravenously (iv), intraperitoneally (ip), and via oral gavage at the following doses: 10mg/kg MnTE-2-PyP(5+) and 0.5 or 2mg/kg MnTnHex-2-PyP(5+). Drug levels in plasma and various organs (liver, kidney, spleen, heart, lung, brain) were determined and PK parameters calculated (Cmax, C24h, tmax, and AUC). Regardless of high water solubility and pentacationic charge of these Mn porphyrins, they are orally available. The oral availability (based on plasma AUCoral/AUCiv) is 23% for MnTE-2-PyP(5+) and 21% for MnTnHex-2-PyP(5+). Despite the fivefold lower dose administered, the AUC values for liver, heart, and spleen are higher for MnTnHex-2-PyP(5+) than for MnTE-2-PyP(5+) (and comparable for other organs), clearly demonstrating the better tissue penetration and tissue retention of the more lipophilic MnTnHex-2-PyP(5+).
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Affiliation(s)
- Tin Weitner
- Department of Radiation Oncology, Duke University Medical Center, Durham, NC 27710, USA
| | - Ivan Kos
- Department of Radiation Oncology, Duke University Medical Center, Durham, NC 27710, USA
| | - Huaxin Sheng
- Department of Anesthesiology, Duke University Medical Center, Durham, NC 27710, USA
- Multidisciplinary Neuroprotection Laboratories, Duke University Medical Center, Durham, NC 27710, USA
| | - Artak Tovmasyan
- Department of Radiation Oncology, Duke University Medical Center, Durham, NC 27710, USA
| | - Julio S. Reboucas
- Department of Radiation Oncology, Duke University Medical Center, Durham, NC 27710, USA
| | - Ping Fan
- Department of Medicine, Duke University Medical Center, Durham, NC 27710, USA
| | - David S. Warner
- Department of Anesthesiology, Duke University Medical Center, Durham, NC 27710, USA
- Multidisciplinary Neuroprotection Laboratories, Duke University Medical Center, Durham, NC 27710, USA
| | - Zeljko Vujaskovic
- Department of Radiation Oncology, Duke University Medical Center, Durham, NC 27710, USA
| | - Ines Batinic-Haberle
- Department of Radiation Oncology, Duke University Medical Center, Durham, NC 27710, USA
| | - Ivan Spasojevic
- Department of Medicine, Duke University Medical Center, Durham, NC 27710, USA
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