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Sadowska-Bartosz I, Bartosz G. The Cellular and Organismal Effects of Nitroxides and Nitroxide-Containing Nanoparticles. Int J Mol Sci 2024; 25:1446. [PMID: 38338725 PMCID: PMC10855878 DOI: 10.3390/ijms25031446] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2023] [Revised: 01/21/2024] [Accepted: 01/22/2024] [Indexed: 02/12/2024] Open
Abstract
Nitroxides are stable free radicals that have antioxidant properties. They react with many types of radicals, including alkyl and peroxyl radicals. They act as mimics of superoxide dismutase and stimulate the catalase activity of hemoproteins. In some situations, they may exhibit pro-oxidant activity, mainly due to the formation of oxoammonium cations as products of their oxidation. In this review, the cellular effects of nitroxides and their effects in animal experiments and clinical trials are discussed, including the beneficial effects in various pathological situations involving oxidative stress, protective effects against UV and ionizing radiation, and prolongation of the life span of cancer-prone mice. Nitroxides were used as active components of various types of nanoparticles. The application of these nanoparticles in cellular and animal experiments is also discussed.
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Affiliation(s)
- Izabela Sadowska-Bartosz
- Laboratory of Analytical Biochemistry, Institute of Food Technology and Nutrition, College of Natural Sciences, University of Rzeszow, 4 Zelwerowicza Street, 35-601 Rzeszow, Poland;
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Bujak-Pietrek S, Pieniazek A, Gwozdzinski K, Gwozdzinski L. The Effect of Piperidine Nitroxides on the Properties of Metalloproteins in Human Red Blood Cells. Molecules 2023; 28:6174. [PMID: 37630426 PMCID: PMC10459006 DOI: 10.3390/molecules28166174] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2023] [Revised: 08/14/2023] [Accepted: 08/18/2023] [Indexed: 08/27/2023] Open
Abstract
Nitroxides are stable, low molecular-weight radicals containing a nitroxide group that has an unpaired electron. The presence of a nitroxide group determines their redox properties. The effect of the piperidine nitroxides, Tempo, Tempol, and Tempamine, on metalloproteins (hemoglobin, superoxide dismutase, catalase) and lactate dehydrogenase in red blood cells was investigated in this research. In addition, the level of lipid peroxidation and the level of protein carbonyl groups were examined as indicators of the effect of oxidative stress. Nitroxides increased superoxide dismutase activity and oxidized hemoglobin to methemoglobin, and also slightly decreased the catalase activity of red blood cells treated with nitroxides. Tempol significantly decreased lactate dehydrogenase activity. All three nitroxides had no effect on membrane lipid peroxidation and protein oxidation. Our results confirm that nitroxides have both antioxidant and prooxidative effects in human red blood cells. The piperidine nitroxides do not initiate the oxidation of proteins and lipids in the membranes of human red blood cells.
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Affiliation(s)
- Stella Bujak-Pietrek
- Department of Physical Hazards, Nofer Institute of Occupational Medicine, 91-348 Lodz, Poland;
| | - Anna Pieniazek
- Department of Oncobiology and Epigenetics, Faculty of Biology and Environmental Protection, University of Lodz, 90-236 Lodz, Poland; (A.P.); (K.G.)
| | - Krzysztof Gwozdzinski
- Department of Oncobiology and Epigenetics, Faculty of Biology and Environmental Protection, University of Lodz, 90-236 Lodz, Poland; (A.P.); (K.G.)
| | - Lukasz Gwozdzinski
- Department of Pharmacology and Toxicology, Medical University of Lodz, 90-752 Lodz, Poland
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Zhang P, Zhang Y, Wang L, Wang X, Xu S, Zhai Z, Wang C, Cai H. Reversal of NADPH Oxidase-Dependent Early Oxidative and Inflammatory Responses in Chronic Obstructive Pulmonary Disease by Puerarin. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2022; 2022:5595781. [PMID: 35651727 PMCID: PMC9151001 DOI: 10.1155/2022/5595781] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Revised: 10/04/2021] [Accepted: 10/30/2021] [Indexed: 12/04/2022]
Abstract
In the present study, we investigated effects of Puerarin on the early oxidative and inflammatory responses in the lung triggered by acute cigarette smoking (ACS). C57BL/6 mice were exposed to ACS for 1 hr in the presence or absence of Puerarin and harvested at 2, 6, and 24 hours. ACS induced significant increases in superoxide production in mouse lungs at 2 and 6 hours; and superoxide production was also elevated in a time and concentration dependent manner in cigarette smoke extract (CSE) stimulated human small airway epithelial cells (HSAECs), which was dose-dependently abrogated by Puerarin. ACS exposure upregulated NOX1, NOX2, and NOX4 protein expression in mouse lungs. Likewise, NOX1 and NOX4 were upregulated in CSE-stimulated HSAECs. These responses were significantly or completely attenuated by Puerarin. ACS induced significant infiltrations of neutrophils and macrophages in mouse lung parenchyma and BAL fluid, which were completely or significantly abrogated by Puerarin, so was the activation of the NF-кB pathway and the upregulation in inflammatory mediators including TNF-α, KC (murine homolog of IL-8), COX-2, IL-6 and MCP-1. Nuclear translocation of p65, IL-8 secretion, and upregulation of COX-2 in CSE stimulated HSAECs were also markedly attenuated by Puerarin. Moreover, ACS or CSE stimulated upregulation in reactive oxygen species (ROS) production and expression of inflammatory mediators were alleviated by ROS scavenger TEMPO in vivo and vitro, with no synergy combining with Puerarin, indicating that the effects of Puerarin are redox-sensitive following activation of NOX. In summary, our data for the first time demonstrate that Puerarin robustly attenuates NOX isoform-dependent ROS production and inflammatory activation in ACS exposed mice and CSE treated HSAECs, indicating that Puerarin might be used as a robust therapeutic agent for early or early stage COPD.
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Affiliation(s)
- Pan Zhang
- Department of Pulmonary and Critical Care Medicine, China-Japan Friendship Hospital, Beijing University of Chinese Medicine, Beijing, China
| | - Yixuan Zhang
- Division of Molecular Medicine, Department of Anesthesiology, Division of Cardiology, Department of Medicine, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, USA
| | - Lu Wang
- Department of Pulmonary and Critical Care Medicine, China-Japan Friendship Hospital, Beijing University of Chinese Medicine, Beijing, China
| | - Xinjing Wang
- Department of Pulmonary and Critical Care Medicine, China-Japan Friendship Hospital, Beijing University of Chinese Medicine, Beijing, China
| | - Shiqing Xu
- Department of Pulmonary and Critical Care Medicine, China-Japan Friendship Hospital, Beijing University of Chinese Medicine, Beijing, China
| | - Zhenguo Zhai
- Department of Pulmonary and Critical Care Medicine, China-Japan Friendship Hospital, Beijing University of Chinese Medicine, Beijing, China
| | - Chen Wang
- Department of Pulmonary and Critical Care Medicine, China-Japan Friendship Hospital, Beijing University of Chinese Medicine, Beijing, China
- Institute of Respiratory Medicine, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Hua Cai
- Division of Molecular Medicine, Department of Anesthesiology, Division of Cardiology, Department of Medicine, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, USA
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Banerjee S, Katiyar P, Kumar V, Saini SS, Varshney R, Krishnan V, Sircar D, Roy P. Black pepper and piperine induce anticancer effects on leukemia cell line. Toxicol Res (Camb) 2021; 10:169-182. [PMID: 33884168 DOI: 10.1093/toxres/tfab001] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Revised: 12/16/2020] [Accepted: 01/01/2021] [Indexed: 11/12/2022] Open
Abstract
The black pepper, most commonly used in Indian cuisines for ages, is considered as "king of spices." The present study evaluates the anticancer potential of black pepper and its main constituent, i.e. alkaloid piperine, against human leukemia cell line, K-562 cells. Gas chromatography-mass spectrometry (GC-MS) analysis confirmed the presence of piperine in black pepper extract. The methanolic extract of black pepper (BP-M) and pure piperine (PIP) showed a strong cytotoxic effect against this cell line. Both BP-M and PIP generated apoptotic bodies in K-562 cells and caused nuclear condensation as visualized by fluorescent microscopy, which was further confirmed by flow cytometry analysis. BP-M and PIP also generated reactive oxygen species in K-562 cells as established by flow cytometry. The translation of Bax, caspase-3 and caspase-9 genes was found to be upregulated with subsequent downregulation of Bcl-2 gene. The anti-proliferative effect of both BP-M and PIP was also observed by trypan blue staining and was further confirmed by the downregulated expression of proliferating cell nuclear antigen (PCNA). The molecular docking studies showed the binding of PIP with PCNA and Bcl-2 and supported the in vitro findings. The docking studies also proposed the binding of PIP to ADP binding pocket of Apaf-1 protein. Taken together, these findings signify the anticancer potential of both black pepper and PIP, thus proposing black pepper as a potent nutraceutical for preventing the progression of chronic myeloid leukemia.
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Affiliation(s)
- Somesh Banerjee
- Molecular Endocrinology Laboratory, Department of Biotechnology, Indian Institute of Technology Roorkee, Roorkee 247667, Uttarakhand, India
| | - Parul Katiyar
- Molecular Endocrinology Laboratory, Department of Biotechnology, Indian Institute of Technology Roorkee, Roorkee 247667, Uttarakhand, India
| | - Vijay Kumar
- Laboratory of Structural Microbiology, Regional Centre for Biotechnology, Faridabad 121001, Haryana, India
| | - Shashank Sagar Saini
- Plant Molecular Biology Laboratory, Department of Biotechnology, Indian Institute of Technology Roorkee, Roorkee 247667, Uttarakhand, India
| | - Ritu Varshney
- Molecular Endocrinology Laboratory, Department of Biotechnology, Indian Institute of Technology Roorkee, Roorkee 247667, Uttarakhand, India
| | - Vengadesan Krishnan
- Laboratory of Structural Microbiology, Regional Centre for Biotechnology, Faridabad 121001, Haryana, India
| | - Debabrata Sircar
- Plant Molecular Biology Laboratory, Department of Biotechnology, Indian Institute of Technology Roorkee, Roorkee 247667, Uttarakhand, India
| | - Partha Roy
- Molecular Endocrinology Laboratory, Department of Biotechnology, Indian Institute of Technology Roorkee, Roorkee 247667, Uttarakhand, India
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Shashni B, Nagasaki Y. Newly Developed Self-Assembling Antioxidants as Potential Therapeutics for the Cancers. J Pers Med 2021; 11:jpm11020092. [PMID: 33540693 PMCID: PMC7912983 DOI: 10.3390/jpm11020092] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Revised: 01/19/2021] [Accepted: 01/28/2021] [Indexed: 02/07/2023] Open
Abstract
Elevated reactive oxygen species (ROS) have been implicated as significant for cancer survival by functioning as oncogene activators and secondary messengers. Hence, the attenuation of ROS-signaling pathways in cancer by antioxidants seems a suitable therapeutic regime for targeting cancers. Low molecular weight (LMW) antioxidants such as 2,2,6,6-tetramethylpyperidine-1-oxyl (TEMPO), although they are catalytically effective in vitro, exerts off-target effects in vivo due to their size, thus, limiting their clinical use. Here, we discuss the superior impacts of our TEMPO radical-conjugated self-assembling antioxidant nanoparticle (RNP) compared to the LMW counterpart in terms of pharmacokinetics, therapeutic effect, and adverse effects in various cancer models.
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Affiliation(s)
- Babita Shashni
- Department of Materials Science, Graduate School of Pure and Applied Sciences, University of Tsukuba, Tennoudai 1-1-1, Tsukuba, Ibaraki 305-8573, Japan;
| | - Yukio Nagasaki
- Department of Materials Science, Graduate School of Pure and Applied Sciences, University of Tsukuba, Tennoudai 1-1-1, Tsukuba, Ibaraki 305-8573, Japan;
- Master’s School of Medical Sciences, Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tennoudai 1-1-1, Tsukuba, Ibaraki 305-8573, Japan
- Center for Research in Isotopes and Environmental Dynamics (CRiED), University of Tsukuba, Tennoudai 1-1-1, Tsukuba, Ibaraki 305-8573, Japan
- Correspondence: ; Fax: +81-(0)29-853-5750
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Ye S, Xu P, Huang M, Chen X, Zeng S, Wang Q, Chen J, Li K, Gao W, Liu R, Liu J, Shao Y, Zhang H, Xu Y, Zhang Q, Zhong Z, Wei Z, Wang J, Hao B, Huang W, Liu Q. The heterocyclic compound Tempol inhibits the growth of cancer cells by interfering with glutamine metabolism. Cell Death Dis 2020; 11:312. [PMID: 32366855 PMCID: PMC7198543 DOI: 10.1038/s41419-020-2499-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Revised: 04/05/2020] [Accepted: 04/06/2020] [Indexed: 12/17/2022]
Abstract
Tempol (4-hydroxy-2,2,6,6-Tetramethylpiperidine-1-oxyl, TPL), a nitroxide compound, inhibits proliferation and increases the vulnerability of cancer cells to apoptosis induced by cytotoxic agents. However, the molecular mechanism of TPL inhibiting cancer cell proliferation has not been fully understood. In this study, we evaluated the metabolic effect of TPL on cancer cells and explored its cancer therapeutic potential. Extracellular flow assays showed that TPL inhibited cellular basal and maximal oxygen consumption rates of mitochondrial. 13C metabolic flux analysis showed that TPL treatment had minimal effect on glycolysis. However, we found that TPL inhibits glutamine metabolism by interfering with the oxidative tricarboxylic acid cycle (TCA) process and reductive glutamine process. We found that the inhibitory effect of TPL on metabolism occurs mainly on the step from citrate to α-ketoglutarate or vice versa. We also found that activity of isocitrate dehydrogenase IDH1 and IDH2, the key enzymes in TCA, were inhibited by TPL treatment. In xenograft mouse model, TPL treatment reduced tumor growth by inhibiting cellular proliferation of xenograft tumors. Thus, we provided a mechanism of TPL inhibiting cancer cell proliferation by interfering with glutamine utilization that is important for survival and proliferation of cancer cells. The study may help the development of a therapeutic strategy of TPL combined with other anticancer medicines.
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Affiliation(s)
- Shuangyan Ye
- Cancer Research Institute, Guangdong Provincial Key Laboratory of Cancer Immunotherapy, Guangzhou Key Laboratory of Tumor Immunology Research, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
| | - Pengfei Xu
- Cancer Research Institute, Guangdong Provincial Key Laboratory of Cancer Immunotherapy, Guangzhou Key Laboratory of Tumor Immunology Research, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
| | - Mengqiu Huang
- Cancer Research Institute, Guangdong Provincial Key Laboratory of Cancer Immunotherapy, Guangzhou Key Laboratory of Tumor Immunology Research, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
| | - Xi Chen
- Cancer Research Institute, Guangdong Provincial Key Laboratory of Cancer Immunotherapy, Guangzhou Key Laboratory of Tumor Immunology Research, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
| | - Sisi Zeng
- Cancer Research Institute, Guangdong Provincial Key Laboratory of Cancer Immunotherapy, Guangzhou Key Laboratory of Tumor Immunology Research, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
| | - Qianli Wang
- Cancer Research Institute, Guangdong Provincial Key Laboratory of Cancer Immunotherapy, Guangzhou Key Laboratory of Tumor Immunology Research, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
| | - Jianping Chen
- Cancer Research Institute, Guangdong Provincial Key Laboratory of Cancer Immunotherapy, Guangzhou Key Laboratory of Tumor Immunology Research, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
| | - Keyi Li
- Cancer Research Institute, Guangdong Provincial Key Laboratory of Cancer Immunotherapy, Guangzhou Key Laboratory of Tumor Immunology Research, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
| | - Wenwen Gao
- Cancer Research Institute, Guangdong Provincial Key Laboratory of Cancer Immunotherapy, Guangzhou Key Laboratory of Tumor Immunology Research, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
| | - Ruiyuan Liu
- School of Biomedical Engineering, Southern Medical University, Guangzhou, China
| | - Jingxian Liu
- Cancer Research Institute, Guangdong Provincial Key Laboratory of Cancer Immunotherapy, Guangzhou Key Laboratory of Tumor Immunology Research, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
| | - Yihao Shao
- The First Affiliated Hospital of Jinan University, Guangzhou, China
| | - Hui Zhang
- Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, China
| | - Yang Xu
- Cancer Research Institute, Guangdong Provincial Key Laboratory of Cancer Immunotherapy, Guangzhou Key Laboratory of Tumor Immunology Research, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
| | - Qianbing Zhang
- Cancer Research Institute, Guangdong Provincial Key Laboratory of Cancer Immunotherapy, Guangzhou Key Laboratory of Tumor Immunology Research, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
| | - Zhuo Zhong
- Guangzhou Hospital of integrated Traditional and West Medicine, Guangzhou, China
| | - Zibo Wei
- Center for medical transformation, Shunde Hospital, Southern Medical University, Foshan, China
| | - Jiale Wang
- Center for medical transformation, Shunde Hospital, Southern Medical University, Foshan, China
| | - Bingtao Hao
- Cancer Research Institute, Guangdong Provincial Key Laboratory of Cancer Immunotherapy, Guangzhou Key Laboratory of Tumor Immunology Research, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China.
| | - Wenhua Huang
- National Key Discipline of Human Anatomy, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China. .,Department of Human Anatomy, School of Basic Medical Sciences, Guangdong Medical University, Guangzhou, China.
| | - Qiuzhen Liu
- Cancer Research Institute, Guangdong Provincial Key Laboratory of Cancer Immunotherapy, Guangzhou Key Laboratory of Tumor Immunology Research, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China. .,Center for medical transformation, Shunde Hospital, Southern Medical University, Foshan, China.
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Guo X, Seo JE, Bryce SM, Tan JA, Wu Q, Dial SL, Moore MM, Mei N. Comparative Genotoxicity of TEMPO and 3 of Its Derivatives in Mouse Lymphoma Cells. Toxicol Sci 2019; 163:214-225. [PMID: 29385624 DOI: 10.1093/toxsci/kfy022] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
TEMPO (2, 2, 6, 6-tetramethylphiperidine-1-oxyl) and its derivatives are stable free radical nitroxides widely used in the field of chemistry, biology, and pharmacology. TEMPO was previously found to be mutagenic and to induce micronuclei in mammalian cells. In this study, we investigated and quantified the genotoxicity of 4 structurally similar nitroxides, TEMPO and 3 of its derivatives (4-hydroxy-TEMPO, 4-oxo-TEMPO, and 4-methoxy-TEMPO), using the mouse lymphoma assay (MLA) and Comet assay in L5178Y Tk+/- cells. The results showed that all tested nitroxides were cytotoxic and mutagenic in the MLA, both in the presence and absence of S9, with metabolic activation significantly enhancing the cytotoxicity and/or mutagenicity. In addition, the 4 nitroxides caused DNA-strand breakage. The mutagenicity and DNA damaging dose-responses of the test articles were compared using the PROAST benchmark dose software package. The potency ranking of the 4 nitroxides for mutagenicity was different from the ranking of the DNA damaging effects. The mode of action analysis by a multi-endpoint DNA damage pathway assay classified all 4 nitroxides as clastogens. In addition, the majority of the induced Tk mutants showed loss of heterozygosity at the Tk and D11Mit42 loci (ie, chromosome damage <31 Mbp). These results suggest that TEMPO and its 3 derivatives are cytotoxic and mutagenic in mouse lymphoma cells through a mechanism that involves strand breakage and large alterations to DNA. The potency rankings indicate that the different TEMPO derivatives vary in their mutagenic and DNA damaging potential.
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Affiliation(s)
- Xiaoqing Guo
- Division of Genetic and Molecular Toxicology, National Center for Toxicological Research, Jefferson, Arkansas 72079
| | - Ji-Eun Seo
- Division of Genetic and Molecular Toxicology, National Center for Toxicological Research, Jefferson, Arkansas 72079
| | | | - Jenna A Tan
- Division of Genetic and Molecular Toxicology, National Center for Toxicological Research, Jefferson, Arkansas 72079
| | - Qiangen Wu
- Division of Biochemical Toxicology, National Center for Toxicological Research, Jefferson, Arkansas 72079
| | - Stacey L Dial
- Division of Genetic and Molecular Toxicology, National Center for Toxicological Research, Jefferson, Arkansas 72079
| | - Martha M Moore
- Division of Genetic and Molecular Toxicology, National Center for Toxicological Research, Jefferson, Arkansas 72079
| | - Nan Mei
- Division of Genetic and Molecular Toxicology, National Center for Toxicological Research, Jefferson, Arkansas 72079
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Ma YZ, Tang ZB, Sang CY, Qi ZY, Hui L, Chen SW. Synthesis and biological evaluation of nitroxide labeled pyrimidines as Aurora kinase inhibitors. Bioorg Med Chem Lett 2019; 29:694-699. [PMID: 30728112 DOI: 10.1016/j.bmcl.2019.01.034] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Revised: 01/28/2019] [Accepted: 01/29/2019] [Indexed: 02/06/2023]
Abstract
To find novel effective Aurora kinases inhibitors, a series of structurally interesting nitroxide labeled pyrimidines were synthesized and evaluated their anti-proliferative and Aurora kinases inhibitory activities. Among them, butyl 2-(3-((5-fluoro-2-((4-((1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl)carbamoyl) phenyl) amino)pyrimidin-4-yl)amino)-1H-pyrazol-5-yl)acetate (22) possessed the most potent anti-proliferative effects against four carcinoma cell lines with IC50 values in range of 0.89-11.41 μM, and kinases inhibition against Aurora A and B with the IC50 values were 9.3 and 2.8 nM, respectively. Furthermore, compound 22 blocked the phosphorylation of Aurora A (T288), Aurora B (Thr232) and HisH3, decreased the expression of proteins TPX2, Eg5 and Bora, as well as disrupted the mitotic spindle formation in HeLa cells. Molecular docking studies indicated that compound 22 well interact with both Aurora A and B. The results showed that compound 22 is a potential anticancer agent as promising pan-Aurora kinase inhibitor.
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Affiliation(s)
- You-Zhen Ma
- School of Pharmacy, Lanzhou University, Lanzhou 730000, China
| | - Zhen-Bo Tang
- School of Pharmacy, Lanzhou University, Lanzhou 730000, China
| | - Chun-Yan Sang
- School of Pharmacy, Lanzhou University, Lanzhou 730000, China
| | - Zhi-Yuan Qi
- School of Pharmacy, Lanzhou University, Lanzhou 730000, China
| | - Ling Hui
- Experimental Center of Medicine, General Hospital of Lanzhou Military Command, Lanzhou 730050, China; Key Laboratory of Stem Cells and Gene Drug of Gansu Province, General Hospital of Lanzhou Military Command, Lanzhou 730050, China
| | - Shi-Wu Chen
- School of Pharmacy, Lanzhou University, Lanzhou 730000, China.
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Sang CY, Qin WW, Zhang XJ, Xu Y, Ma YZ, Wang XR, Hui L, Chen SW. Synthesis and identification of 2,4-bisanilinopyrimidines bearing 2,2,6,6-tetramethylpiperidine-N-oxyl as potential Aurora A inhibitors. Bioorg Med Chem 2019; 27:65-78. [DOI: 10.1016/j.bmc.2018.11.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Revised: 10/16/2018] [Accepted: 11/05/2018] [Indexed: 12/26/2022]
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Kim HK, Hwang SH, Abdi S. Tempol Ameliorates and Prevents Mechanical Hyperalgesia in a Rat Model of Chemotherapy-Induced Neuropathic Pain. Front Pharmacol 2017; 7:532. [PMID: 28138318 PMCID: PMC5237846 DOI: 10.3389/fphar.2016.00532] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2016] [Accepted: 12/22/2016] [Indexed: 01/01/2023] Open
Abstract
Chemotherapy-induced neuropathic pain is difficult to treat and prevent. Tempol decreases cellular superoxide radical levels and oxidative stress. The aims of our study were to investigate the analgesic and preventive effects of tempol on paclitaxel-induced neuropathic pain in rats and to identify the associated mechanisms of action. Neuropathic pain was induced with intraperitoneally injected paclitaxel on four alternate days in male Sprague-Dawley rats. Tempol was administered systemically as a single injection and a continuous infusion before or after the injection of paclitaxel. The mechanical threshold for allodynia, protein levels, and free radical levels were measured using von Frey filaments, Western blotting, and live cell imaging, respectively. After the rats developed neuropathic pain behavior, a single intraperitoneal injection and continuous infusion of tempol ameliorated paclitaxel-induced mechanical allodynia. Systemic infusion of tempol in the early phase of the development of pain behavior prevented the development of paclitaxel-induced pain behavior. Paclitaxel increased the levels of phosphorylated protein kinase C, phosphorylated nuclear factor κB, phosphodiesterase 4D (PDE4D), IL-1β, and monocyte chemoattractant protein-1 in the lumbar dorsal root ganglia; however, tempol decreased these levels. Paclitaxel also increased superoxide levels in a culture of primary dorsal root ganglion cells and tempol decreased these levels. In conclusion, tempol alleviates and prevents chemotherapy-induced neuropathic pain in rats by reducing the levels of inflammatory cytokines and free radicals in dorsal root ganglia.
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Affiliation(s)
- Hee Kee Kim
- Department of Pain Medicine, Division of Anesthesiology and Critical Care, The University of Texas MD Anderson Cancer Center Houston, TX, USA
| | - Seon-Hee Hwang
- Department of Pain Medicine, Division of Anesthesiology and Critical Care, The University of Texas MD Anderson Cancer Center Houston, TX, USA
| | - Salahadin Abdi
- Department of Pain Medicine, Division of Anesthesiology and Critical Care, The University of Texas MD Anderson Cancer Center Houston, TX, USA
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Liu Y, Gao J, Huang S, Hu L, Wang Z, Wang Z, Chen X, Zhang X, Li W. 4-isothiocyanate-2, 2, 6, 6-tetramethyl piperidinooxyl inhibits angiogenesis by suppressing VEGFR2 and Tie2 phosphorylation. Oncol Lett 2016; 12:2828-2834. [PMID: 27698866 DOI: 10.3892/ol.2016.4948] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2015] [Accepted: 07/20/2016] [Indexed: 01/06/2023] Open
Abstract
Reactive oxygen species (ROS) are involved in the signaling pathway and are triggered by angiogenic factors, including vascular endothelial growth factor and angiopoietins. 4-isothiocyanate-2, 2, 6, 6-tetramethyl piperidinooxyl (4-ISO-Tempo) is one of the nitroxides that exhibits antioxidant activity. However, the anti-angiogenic effect of 4-ISO-Tempo remains unknown. The aim of this study was to investigate the effect of 4-ISO-Tempo on tumor proliferation and angiogenesis as well as its underlying mechanisms. Our results revealed that 4-ISO-Tempo significantly inhibited the viability of neoplastic and endothelial cells. Furthermore, the effective concentration of 4-ISO-Tempo on human microvascular endothelial cell 1 (HMEC-1) was lower than that on human lung adenocarcinoma A549 and human colon cancer SW620 cells. This suggested that endothelial cells were more sensitive to 4-ISO-Tempo than tumor cells. Furthermore, we demonstrated that 4-ISO-Tempo also suppressed secretion of matrix metalloproteinase (MMP)-2 and MMP-9, and migration and tube formation of HMEC-1 cells. The mechanism is attributed to the decreasing ROS generation and further phosphorylation of vascular endothelial growth factor receptor 2 and Tie2. Our findings suggest that 4-ISO-Tempo should be investigated for its usefulness in anti-angiogenesis therapies.
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Affiliation(s)
- Yuanyuan Liu
- College of Basic Medicine, Key Laboratory of Preclinical Study for New Drugs of Gansu, Lanzhou University, Lanzhou, Gansu 730000, P.R. China; Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou, Gansu 730000, P.R. China
| | - Jing Gao
- Clinical Laboratory, Affiliated Hospital of Medical College of Northwest University for Nationalities, Lanzhou, Gansu 730030, P.R. China
| | - Shuangsheng Huang
- Clinical Laboratory, Affiliated Hospital of Medical College of Northwest University for Nationalities, Lanzhou, Gansu 730030, P.R. China
| | - Lamei Hu
- College of Basic Medicine, Key Laboratory of Preclinical Study for New Drugs of Gansu, Lanzhou University, Lanzhou, Gansu 730000, P.R. China
| | - Zhiqiang Wang
- College of Basic Medicine, Key Laboratory of Preclinical Study for New Drugs of Gansu, Lanzhou University, Lanzhou, Gansu 730000, P.R. China
| | - Zheyuan Wang
- Department of General Surgery, Second Hospital of Lanzhou University, Lanzhou, Gansu 730030, P.R. China
| | - Xiao Chen
- Department of General Surgery, Second Hospital of Lanzhou University, Lanzhou, Gansu 730030, P.R. China
| | - Xiaoyu Zhang
- College of Basic Medicine, Key Laboratory of Preclinical Study for New Drugs of Gansu, Lanzhou University, Lanzhou, Gansu 730000, P.R. China
| | - Wenguang Li
- College of Basic Medicine, Key Laboratory of Preclinical Study for New Drugs of Gansu, Lanzhou University, Lanzhou, Gansu 730000, P.R. China
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Komleva NV, Lapshina MA, Kostyuk GV, Ivanov AV, Parkhomenko II, Papina RI, Sen´ VD, Terentiev AA. Comparative analysis of cytotoxic effects and intracellular accumulation of platinum(IV) nitroxyl complexes. Russ Chem Bull 2016. [DOI: 10.1007/s11172-015-0996-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
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13
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Reactive oxygen species and c-Jun N-terminal kinases contribute to TEMPO-induced apoptosis in L5178Y cells. Chem Biol Interact 2015; 235:27-36. [PMID: 25882087 DOI: 10.1016/j.cbi.2015.04.009] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2014] [Revised: 03/04/2015] [Accepted: 04/08/2015] [Indexed: 01/14/2023]
Abstract
The biological consequences of exposure to piperidine nitroxides is a concern, given their widespread use in manufacturing processes and their potential use in clinical applications. Our previous study reported that TEMPO (2,2,6,6-tetramethylpiperidine-1-oxyl), a low molecular weight free radical, possesses pro-oxidative activity in L5178Y cells. In this study, we investigated and characterized the role of reactive oxygen species (ROS) in TEMPO-induced toxicity in L5178Y cells. We found that TEMPO induced time- and concentration-dependent intracellular ROS production and glutathione depletion. TEMPO also induced apoptosis as demonstrated by increased caspase-3/7 activity, an increased proportion of annexin V stained cells, and decreased expression of anti-apoptotic proteins including Bcl-2, Bcl-xL and Mcl-1. N-acetylcysteine, a ROS scavenger, attenuated the ROS production and apoptosis induced by TEMPO. Moreover, Western blot analyses revealed that TEMPO activated γ-H2A.X, a hallmark of DNA damage, and c-Jun N-terminal kinases (JNK), a key member in the mitogen-activated protein kinase (MAPK) signaling pathway. Addition of SP600125, a JNK-specific inhibitor, blocked TEMPO-mediated JNK phosphorylation and also attenuated TEMPO-induced apoptosis. These findings indicate that both ROS production and JNK activation are involved in TEMPO-induced apoptosis, and may contribute to the toxicity of TEMPO in L5178Y cells.
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Tabaczar S, Domeradzka K, Czepas J, Piasecka-Zelga J, Stetkiewicz J, Gwoździński K, Koceva-Chyła A. Anti-tumor potential of nitroxyl derivative Pirolin in the DMBA-induced rat mammary carcinoma model: A comparison with quercetin. Pharmacol Rep 2015; 67:527-34. [PMID: 25933965 DOI: 10.1016/j.pharep.2014.12.010] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2014] [Revised: 10/21/2014] [Accepted: 12/18/2014] [Indexed: 01/29/2023]
Abstract
BACKGROUND Considering the role of oxidative stress in carcinogenesis, we investigated the effect of synthetic antioxidant Pirolin (3-carbamoyl-2,2,5,5-tetramethylpyrroline-1-oxyl) on breast cancer progression. Since the anticancer drugs may cause cardiotoxicity due to oxidative stress in the heart muscle, we also evaluated Pirolin performance in heart tissue and compared its effect with that of the natural dietary flavonoid quercetin. METHODS Sprague-Dawley rats were administered with 7,12-dimethylbenz(a)anthracene (DMBA) and then treated ip with an antioxidant (each at a dose of 10mg/kg b.w.) for 14 days. The histopathology of tumors, their size and multiplicity were assesed. The effect of antioxidants on heart tissue was evaluated by the oxidative stress markers and poly (ADP-ribose) polymerase 1 (PARP 1) cleavage. RESULTS The median number of tumors and their volume, at the end of the study, were considerably smaller in both antioxidant-treated groups. We found a better antioxidative performance of quercetin in the heart, since a restoration of the GSH pool and decreased amount of hydroperoxides were observed. Antioxidants did not prevent cardiomyocytes from apoptosis. CONCLUSION The attenuation of tumor progression by Pirolin was comparable with the action of quercetin. No negative changes were observed in the heart of animals after Pirolin treatment. Thus, its use in targeting deregulated redox pathways should be further studied.
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Affiliation(s)
- Sabina Tabaczar
- Department of Molecular Biophysics, Faculty of Biology and Environmental Protection, University of Łódź, Łódź, Poland.
| | | | - Jan Czepas
- Department of Molecular Biophysics, Faculty of Biology and Environmental Protection, University of Łódź, Łódź, Poland
| | | | | | - Krzysztof Gwoździński
- Department of Molecular Biophysics, Faculty of Biology and Environmental Protection, University of Łódź, Łódź, Poland
| | - Aneta Koceva-Chyła
- Department of Thermobiology, Faculty of Biology and Environmental Protection, University of Łódź, Łódź, Poland
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15
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Sen’ VD, Tikhonov IV, Borodin LI, Pliss EM, Golubev VA, Syroeshkin MA, Rusakov AI. Kinetics and thermodynamics of reversible disproportionation-comproportionation in redox triad oxoammonium cations - nitroxyl radicals - hydroxylamines. J PHYS ORG CHEM 2014. [DOI: 10.1002/poc.3392] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- Vasily D. Sen’
- Institute of Problems of Chemical Physics; Russian Academy of Sciences; Chernogolovka 142432 Russian Federation
| | - Ivan V. Tikhonov
- P.G. Demidov Yaroslavl State University; Yaroslavl 150000 Russian Federation
| | - Leonid I. Borodin
- P.G. Demidov Yaroslavl State University; Yaroslavl 150000 Russian Federation
| | - Evgeny M. Pliss
- P.G. Demidov Yaroslavl State University; Yaroslavl 150000 Russian Federation
| | - Valery A. Golubev
- Institute of Problems of Chemical Physics; Russian Academy of Sciences; Chernogolovka 142432 Russian Federation
| | - Mikhail A. Syroeshkin
- N. D. Zelinsky Institute of Organic Chemistry; Russian Academy of Sciences; Moscow 119991 Russian Federation
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16
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Mitochondria-targeted antioxidant and glycolysis inhibition: synergistic therapy in hepatocellular carcinoma. Anticancer Drugs 2014; 24:881-8. [PMID: 23872912 DOI: 10.1097/cad.0b013e32836442c6] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Hepatocellular carcinoma (HCC) is the third leading cause of cancer-related deaths worldwide. Mito-carboxy proxyl (Mito-CP), a lipophilic cationic nitroxide, accumulates in the mitochondria because of the large negative transmembrane potential. Studies have shown that these agents act by disrupting the energy-producing mechanism, inducing mitochondrial-mediated apoptosis, and also enhancing the action of other chemotherapeutic agents in cancer cells. We hypothesized that the combination of Mito-CP and glycolysis inhibitor, 2-deoxyglucose (2-DG), would synergistically inhibit HCC in vitro. HepG2 cells and primary hepatocytes were treated with various combinations of Mito-CP and 2-DG. Cell cytotoxicity was measured using the methylthiazolyldiphenyl-tetrazolium bromide assay and ATP bioluminescence assay. In addition, caspase 3/7 enzymatic activity was examined after treatment. Mito-CP and 2-DG induced synergistic cytotoxicity in HepG2 cells in a dose-dependent and time-dependent manner, whereas primary cells remained viable and unaffected after treatment. The intracellular ATP levels of HepG2 cells were suppressed within 6 h of combination treatment, whereas primary cells maintained higher levels of ATP. Dose-dependent increases in caspase 3/7 activity occurred in HepG2 cells in a time-dependent manner, showing the initiation of cell death through the apoptotic pathway. These findings indicate that a combination of Mito-CP and 2-DG effectively inhibits HCC growth in vitro. The increase in caspase 3/7 activity supports the occurrence of 2-DG-induced and Mito-CP-induced apoptotic death in HCC. The inability of the compounds to induce cytotoxicity or suppress the production of ATP in primary hepatocytes provides a selective and synergistic approach for the treatment of HCC.
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17
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Wang H, Jia Y, Gao P, Cheng Y, Cheng M, Lu C, Zhou S, Sun X. Synthesis, radioprotective activity and pharmacokinetics characteristic of a new stable nitronyl nitroxyl radical-NIT2011. Biochimie 2013; 95:1574-81. [DOI: 10.1016/j.biochi.2013.04.011] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2013] [Accepted: 04/13/2013] [Indexed: 11/24/2022]
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18
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Li S, Guo C, Sun X, Li Y, Zhao H, Zhan D, Lan M, Tang Y. Synthesis and biological evaluation of quinazoline and quinoline bearing 2,2,6,6-tetramethylpiperidine-N-oxyl as potential epidermal growth factor receptor(EGFR) tyrosine kinase inhibitors and EPR bio-probe agents. Eur J Med Chem 2012; 49:271-8. [DOI: 10.1016/j.ejmech.2012.01.021] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2011] [Revised: 01/08/2012] [Accepted: 01/10/2012] [Indexed: 10/14/2022]
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19
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Thomas R, Sharifi N. SOD mimetics: a novel class of androgen receptor inhibitors that suppresses castration-resistant growth of prostate cancer. Mol Cancer Ther 2011; 11:87-97. [PMID: 22172488 DOI: 10.1158/1535-7163.mct-11-0540] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Advanced prostate cancer is the second leading cause of cancer-related deaths among American men. The androgen receptor (AR) is vital for prostate cancer progression, even in the face of castrate levels of serum testosterone following androgen ablation therapy, a mainstay therapy for advanced prostate cancer. Downregulation of superoxide dismutase 2 (SOD2), a major intracellular antioxidant enzyme, occurs progressively during prostate cancer progression to advanced states and is known to promote AR activity in prostate cancer. Therefore, this study investigated the effects of SOD mimetics on AR expression and function in AR-dependent LNCaP, CWR22Rv1, and LAPC-4AD prostate cancer cells. Treatment with Tempol (4-hydroxy-2,2,6,6-tetramethylpiperidine-N-oxyl), a SOD mimetic, not only lowered cellular superoxide levels but also concomitantly attenuated AR transcriptional activity and AR target gene expression in a dose- and time-dependent manner, in the presence and absence of dihydrotestosterone, the major endogenous AR agonist. Inhibition of AR by Tempol was mediated, in large part, by its ability to decrease AR protein via increased degradation, in the absence of any inhibitory effects on other nuclear receptors. Inhibitory effects of Tempol on AR were also reproducible with other SOD mimetics, MnTBAP and MnTMPyP. Importantly, effects of Tempol on AR function were accompanied by significant in vitro and in vivo reduction in castration-resistant prostate cancer (CRPC) survival and growth. Collectively, this study has shown for the first time that SOD mimetics, by virtue of their ability to suppress AR function, may be beneficial in treating the currently incurable CRPC, in which SOD2 expression is highly suppressed.
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Affiliation(s)
- Rusha Thomas
- Department of Internal Medicine, Division of Hematology/Oncology, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA
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20
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Protection of normal brain cells from γ-irradiation-induced apoptosis by a mitochondria-targeted triphenyl-phosphonium-nitroxide: a possible utility in glioblastoma therapy. J Neurooncol 2010; 100:1-8. [DOI: 10.1007/s11060-010-0387-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2010] [Accepted: 08/24/2010] [Indexed: 12/30/2022]
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21
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Zhao H, Meng X, Yuan H, Lan M. Novel melphalan and chlorambucil derivatives of 2,2,6,6-tetramethyl-1-piperidinyloxy radicals: synthesis, characterization, and biological evaluation in vitro. Chem Pharm Bull (Tokyo) 2010; 58:332-5. [PMID: 20190437 DOI: 10.1248/cpb.58.332] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A series of spin-labeled melphalan and chlorambucil derivatives, coupling the alkylating agents with 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO) radicals, were synthesized, characterized, and their biological properties in vitro were evaluated. These compounds showed much higher cytotoxic activity against human leukemia cell line K562 in vitro than their parent compounds.
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Affiliation(s)
- Hongli Zhao
- Key Laboratory for Advanced Materials, and Research Center of Analysis and Test, East China University of Science and Technology, Shanghai 200237, P. R.China
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22
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Li WG, Zhang XY, Wu YJ, Gao MT, Zheng RL. The relationship between structure and antioxidative activity of piperidine nitroxides. J Pharm Pharmacol 2010; 58:941-9. [PMID: 16805954 DOI: 10.1211/jpp.58.7.0009] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
Abstract
We have investigated the relationship between structure and antioxidative activity of piperidine nitroxides which were substituted by different groups at the 4-position. All of the tested piperidine nitroxides inhibited malondialdehyde (MDA) generation caused either spontaneously or by a hydroxyl free radical generation system (Fe2+-ascorbic acid) in homogenates of liver, heart and kidney of rats, and antagonized H2O2-induced haemolysis from rat erythrocytes in a concentration-dependent manner. The same rank was followed: Bis-(4-amino-2,2,6,6-tetramethyl piperidinooxyl) (4-BIS-Tempo) and 4-azido-2,2,6,6-tetramethyl piperidinooxyl (4-N3-Tempo) >4-isothiocyanate-2,2,6,6-tetramethyl piperidinooxyl (4-ISO-Tempo), 4-2′,4′-dinitrophenyl-hydrazone-2,2,6,6-tetramethyl piperidinooxyl (4-D-Tempo), 4-sulfonate-2,2,6,6-tetramethyl piperidinooxyl (4-S-Tempo) and 4-amino-2,2,6,6-tetramethyl piperidinooxyl (4-NH2-Tempo) > 4-acetate ester-2,2,6,6-tetramethyl piperidinooxyl (4-A-Tempo) and 4-benzoate-2,2,6,6-tetra-methyl piperidinooxyl (4-B-Tempo). With the exception of 4-A-Tempo and 4-D-Tempo, the tested piperidine nitroxides inhibited superoxide anion (O2.-) release from neutrophils stimulated by zymosan. The concentration required for inhibiting O2.- release was higher than that of inhibiting MDA formation and haemolysis. However, 4-amino-2,2,6,6-tetramethyl piperidine (4-NH2-TempH) and other 4-position substitutes, such as NaN3 and isothiocyanate, had no effects on MDA formation, haemolysis or O2.- release. The results indicated that nitroxides have a wide range of scavenging reactive oxygen species (ROS) actions. The nitroxide moiety was the essential group while the 4-position substitutes could influence the activity of nitroxides on scavenging ROS.
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Affiliation(s)
- Wen-Guang Li
- School of Life Sciences, Lanzhou University, Lanzhou, Gansu 730 000, PR China
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23
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Linares E, Giorgio S, Augusto O. Inhibition of in vivo leishmanicidal mechanisms by tempol: nitric oxide down-regulation and oxidant scavenging. Free Radic Biol Med 2008; 44:1668-76. [PMID: 18313408 DOI: 10.1016/j.freeradbiomed.2008.01.027] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/22/2008] [Accepted: 01/24/2008] [Indexed: 11/20/2022]
Abstract
Tempol (4-hydroxy-2,2,6,6-tetramethyl-1-piperidinyloxy) has long been known to protect experimental animals from the injury associated with oxidative and inflammatory conditions. In the latter case, a parallel decrease in tissue protein nitration levels has been observed. Protein nitration represents a shift in nitric oxide actions from physiological to pathophysiological and potentially damaging pathways involving its derived oxidants such as nitrogen dioxide and peroxynitrite. In infectious diseases, protein tyrosine nitration of tissues and cells has been taken as evidence for the involvement of nitric oxide-derived oxidants in microbicidal mechanisms. To examine whether tempol inhibits the microbicidal action of macrophages, we investigated its effects on Leishmania amazonensis infection in vitro (RAW 264.7 murine macrophages) and in vivo (C57Bl/6 mice). Tempol was administered in the drinking water at 2 mM throughout the experiments and shown to reach infected footpads as the nitroxide plus the hydroxylamine derivative by EPR analysis. At the time of maximum infection (6 weeks), tempol increased footpad lesion size (120%) and parasite burden (150%). In lesion extracts, tempol decreased overall nitric oxide products and expression of inducible nitric oxide synthase to about 80% of the levels in control animals. Nitric oxide-derived products produced by radical mechanisms, such as 3-nitrotyrosine and nitrosothiol, decreased to about 40% of the levels in control mice. The results indicate that tempol worsened L. amazonensis infection by a dual mechanism involving down-regulation of iNOS expression and scavenging of nitric oxide-derived oxidants. Thus, the development of therapeutic strategies based on nitroxides should take into account the potential risk of altering host resistance to parasite infection.
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Affiliation(s)
- Edlaine Linares
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, CP 26077, CEP 05513-970 São Paulo, SP, Brazil
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Jiang J, Belikova NA, Hoye AT, Zhao Q, Epperly MW, Greenberger JS, Wipf P, Kagan VE. A mitochondria-targeted nitroxide/hemigramicidin S conjugate protects mouse embryonic cells against gamma irradiation. Int J Radiat Oncol Biol Phys 2008; 70:816-25. [PMID: 18262096 DOI: 10.1016/j.ijrobp.2007.10.047] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2007] [Revised: 10/24/2007] [Accepted: 10/24/2007] [Indexed: 01/07/2023]
Abstract
PURPOSE To evaluate the in vitro radioprotective effect of the mitochondria-targeted hemigramicidin S-conjugated 4-amino-2,2,6,6-tetramethyl-piperidine-N-oxyl (hemi-GS-TEMPO) 5-125 in gamma-irradiated mouse embryonic cells and adenovirus-12 SV40 hybrid virus transformed human bronchial epithelial cells BEAS-2B and explore the mechanisms involved in its radioprotective effect. METHODS AND MATERIALS Cells were incubated with 5-125 before (10 minutes) or after (1 hour) gamma-irradiation. Superoxide generation was determined by using dihydroethidium assay, and lipid oxidation was quantitated by using a fluorescence high-performance liquid chromatography-based Amplex Red assay. Apoptosis was characterized by evaluating the accumulation of cytochrome c in the cytosol and externalization of phosphatidylserine on the cell surface. Cell survival was measured by means of a clonogenic assay. RESULTS Treatment (before and after irradiation) of cells with 5-125 at low concentrations (5, 10, and 20 mum) effectively suppressed gamma-irradiation-induced superoxide generation, cardiolipin oxidation, and delayed irradiation-induced apoptosis, evaluated by using cytochrome c release and phosphatidylserine externalization. Importantly, treatment with 5-125 increased the clonogenic survival rate of gamma-irradiated cells. In addition, 5-125 enhanced and prolonged gamma-irradiation-induced G(2)/M phase arrest. CONCLUSIONS Radioprotection/mitigation by hemi-GS-TEMPO likely is caused by its ability to act as an electron scavenger and prevent superoxide generation, attenuate cardiolipin oxidation in mitochondria, and hence prevent the release of proapoptotic factors from mitochondria. Other mechanisms, including cell-cycle arrest at the G(2)/M phase, may contribute to the protection.
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Affiliation(s)
- Jianfei Jiang
- Center for Medical Countermeasures Against Radiation, University of Pittsburgh, Pittsburgh, PA 15219, USA
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25
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Bayir H, Kagan VE. Bench-to-bedside review: Mitochondrial injury, oxidative stress and apoptosis--there is nothing more practical than a good theory. Crit Care 2008; 12:206. [PMID: 18341705 PMCID: PMC2374589 DOI: 10.1186/cc6779] [Citation(s) in RCA: 109] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Apoptosis contributes to cell death in common intensive care unit disorders such as traumatic brain injury and sepsis. Recent evidence suggests that this form of cell death is both clinically relevant and a potential therapeutic target in critical illness. Mitochondrial reactive oxygen species (ROS) have become a target for drug discovery in recent years since their production is characteristic of early stages of apoptosis. Among many antioxidant agents, stable nitroxide radicals targeted to mitochondria have attracted attention due to their ability to combine electron and free radical scavenging action with recycling capacities. Specific mechanisms of enhanced ROS generation in mitochondria and their translation into apoptotic signals are not well understood. This review focuses on several contemporary aspects of oxidative stress-mediated mitochondrial injury, particularly as they relate to oxidation of lipids and their specific signaling roles in apoptosis and phagocytosis of apoptotic cells.
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Affiliation(s)
- Hülya Bayir
- Safar Center for Resuscitation Research, Department of Critical Care Medicine, School of Medicine, University of Pittsburgh, PA, USA.
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26
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Soule BP, Hyodo F, Matsumoto KI, Simone NL, Cook JA, Krishna MC, Mitchell JB. Therapeutic and clinical applications of nitroxide compounds. Antioxid Redox Signal 2007; 9:1731-43. [PMID: 17665971 DOI: 10.1089/ars.2007.1722] [Citation(s) in RCA: 101] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Nitroxide compounds have been used for many years as biophysical tools, but only during the past 15-20 years have the many interesting biochemical interactions been discovered and harnessed for therapeutic applications. By modifying oxidative stress and altering the redox status of tissues, nitroxides have the ability to interact with and alter many metabolic processes. This interaction can be exploited for therapeutic and research use, including protection against ionizing radiation, as probes in functional magnetic resonance imaging, cancer prevention and treatment, control of hypertension and weight, and protection from damage resulting from ischemia/reperfusion injury. Although much remains to be done, many applications have been well studied, and some are presently being tested in clinical trials. The therapeutic and research uses of nitroxides are reviewed here, with a focus on the progress from initial development to modern, state-of-the art trials.
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Affiliation(s)
- Benjamin P Soule
- Radiation Biology Branch, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland 20892, USA.
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27
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Cotrim AP, Hyodo F, Matsumoto KI, Sowers AL, Cook JA, Baum BJ, Krishna MC, Mitchell JB. Differential radiation protection of salivary glands versus tumor by Tempol with accompanying tissue assessment of Tempol by magnetic resonance imaging. Clin Cancer Res 2007; 13:4928-33. [PMID: 17699873 DOI: 10.1158/1078-0432.ccr-07-0662] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PURPOSE The nitroxide free radical, Tempol, was evaluated for potential differential radiation protection of salivary glands and tumor using fractionated radiation. Mechanistic information was explored by monitoring the presence and bioreduction of Tempol in both tissues noninvasively by magnetic resonance imaging (MRI). EXPERIMENTAL DESIGN Female C3H mice were immobilized using custom-made Lucite jigs for localized irradiation (five daily fractions) either to the oral cavity or tumor-bearing leg. Tempol (275 mg/kg) was administered (i.p.) 10 min before each radiation fraction. Salivary gland damage was assessed 8 weeks after radiation by measuring pilocarpine-mediated saliva output. Tumor growth was assessed by standard radiation regrowth methods. Dynamic T1-weighted magnetic resonance scans were acquired before and after Tempol injection using a 4.7T animal MRI instrument. RESULTS Tempol treatment was found to protect salivary glands significantly against radiation damage (approximately 60% improvement); whereas no tumor protection was observed. Intracellular reduction of Tempol to the nonradioprotective hydroxylamine as assessed by MRI was 2-fold faster in tumor compared with salivary glands or muscle. CONCLUSIONS Tempol provided salivary gland radioprotection and did not protect tumor, consistent with the hypothesis that differential radioprotection by Tempol resides in faster reduction to the nonradioprotective hydroxylamine in tumor compared with normal tissues. The unique paramagnetic properties of Tempol afforded noninvasive MRI monitoring of dynamic changes of Tempol levels in tissue to support the finding. These data support further development and consideration of Tempol for human clinical trials as a selective protector against radiation-induced salivary gland damage.
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Affiliation(s)
- Ana P Cotrim
- Gene Therapy and Therapeutics Branch, National Institute of Dental and Craniofacial Research, NIH, Bethesda, Maryland 20892, USA.
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Czepas J, Koceva-Chyła A, Gwoździński K, Jóźwiak Z. Different effectiveness of piperidine nitroxides against oxidative stress induced by doxorubicin and hydrogen peroxide. Cell Biol Toxicol 2007; 24:101-12. [PMID: 17610030 DOI: 10.1007/s10565-007-9020-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2007] [Accepted: 04/23/2007] [Indexed: 01/29/2023]
Abstract
The piperidine nitroxides Tempamine and Tempace have been studied for their effect on doxorubicin (DOX) and hydrogen peroxide (H(2)O(2)) cytotoxicity in immortalized B14 cells, a model for neoplastic phenotype. The significance for nitroxide performance of the substituent in position 4 of the piperidine ring was evaluated. The cells were exposed to DOX/H(2)O(2) alone or in combination with the nitroxides Tempamine or Tempace. Two other piperidine nitroxides, Tempo and Tempol, were used for comparison. All the nitroxides except Tempamine modestly reduced DOX cytotoxicity. Tempamine evoked a biphasic response: at concentrations lower than 200 micromol/L the nitroxide decreased DOX cytotoxicity, while at concentrations higher than 200 micromol/L, it enhanced DOX cytotoxicity. In contrast to Tempo and Tempol, Tempamine and Tempace ameliorated hydrogen peroxide cytotoxicity, but none of the nitroxides influenced TBARS stimulated by hydrogen peroxide. The cytoprotective effect of Tempace, Tempo and Tempol in DOX-treated cells correlated with the inhibition of DOX-induced lipid peroxidation. The bioreduction rates of the investigated nitroxides differed significantly and were variously affected by DOX depending on the nitroxide substituent. In combination with DOX, Tempo and Tempol were reduced significantly more slowly, while no influence of DOX on Tempamine and Tempace bioreduction was observed. Our results suggest that the structure of the 4-position substituent is an important factor for biological activity of piperidine nitroxides. Among the investigated nitroxides, Tempace displayed the best protective properties in vitro but Tempamine was the only nitroxide that potentiated cytotoxicity of DOX and did not influence DOX-induced lipid peroxidation. However, this nitroxide showed different performance depending on its concentration and conditions of oxidative stress.
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Affiliation(s)
- J Czepas
- Department of Molecular Biophysics, University of Łódź, Łódź, Poland.
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Soule BP, Hyodo F, Matsumoto KI, Simone NL, Cook JA, Krishna MC, Mitchell JB. The chemistry and biology of nitroxide compounds. Free Radic Biol Med 2007; 42:1632-50. [PMID: 17462532 PMCID: PMC1991293 DOI: 10.1016/j.freeradbiomed.2007.02.030] [Citation(s) in RCA: 381] [Impact Index Per Article: 22.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/14/2006] [Revised: 02/21/2007] [Accepted: 02/27/2007] [Indexed: 02/04/2023]
Abstract
Cyclic nitroxides are a diverse group range of stable free radicals that have unique antioxidant properties. Because of their ability to interact with free radicals, they have been used for many years as biophysical tools. During the past 15-20 years, however, many interesting biochemical interactions have been discovered and harnessed for therapeutic applications. Biologically relevant effects of nitroxides have been described, including their ability to degrade superoxide and peroxide, inhibit Fenton reactions, and undergo radical-radical recombination. Cellular studies defined the activity of nitroxides in vitro. By modifying oxidative stress and altering the redox status of tissues, nitroxides have been found to interact with and alter many metabolic processes. These interactions can be exploited for therapeutic and research use, including protection against ionizing radiation, as probes in functional magnetic resonance imaging, cancer prevention and treatment, control of hypertension and weight, and protection from damage resulting from ischemia/reperfusion injury. Although much remains to be done, many applications have been well studied and some are currently being tested in clinical trials. The therapeutic and research uses of nitroxide compounds are reviewed here with a focus on the progress from initial development to modern trials.
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Affiliation(s)
- Benjamin P Soule
- Radiation Biology Branch, Center for Cancer Research, National Cancer Institute, Bethesda, MD 20892, USA.
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Jiang J, Kurnikov I, Belikova NA, Xiao J, Zhao Q, Amoscato AA, Braslau R, Studer A, Fink MP, Greenberger JS, Wipf P, Kagan VE. Structural Requirements for Optimized Delivery, Inhibition of Oxidative Stress, and Antiapoptotic Activity of Targeted Nitroxides. J Pharmacol Exp Ther 2006; 320:1050-60. [PMID: 17179468 DOI: 10.1124/jpet.106.114769] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Suppression of mitochondrial production of reactive oxygen species is a promising strategy against intrinsic apoptosis typical of degenerative diseases. Stable nitroxide radicals such as 4-hydroxy-2,2,6,6-tetramethyl piperidine-1-oxyl (TEMPOL) and its analogs combine several important features, including recycleability, electron acceptance from respiratory complexes, superoxide dismutase mimicry, and radical scavenging. Although successful in antioxidant protection, their effective concentrations are too high for successful in vivo applications. Recently (J Am Chem Soc 127:12460, 2005), we reported that 4-amino 2,2,6,6-tetramethyl-1-piperidinyloxy, covalently conjugated to a five-residue segment of gramicidin S (GS), was integrated into mitochondria and blocked actinomycin D (ActD)-induced superoxide generation and apoptosis. Using a model of ActD-induced apoptosis in mouse embryonic cells, we screened a library of nitroxides to explore structure-activity relationships between their antioxidant/antiapoptotic properties and chemical composition and three-dimensional (3D) structure. High hydrophobicity and effective mitochondrial integration are necessary but not sufficient for high antiapoptotic/antioxidant activity of a nitroxide conjugate. By designing conformationally preorganized peptidyl nitroxide conjugates and characterizing their 3D structure experimentally (circular dichroism and NMR) and theoretically (molecular dynamics), we established that the presence of the beta-turn/beta-sheet secondary structure is essential for the desired activity. Monte Carlo simulations in model lipid membranes confirmed that the conservation of the d-Phe-Pro reverse turn in hemi-GS analogs ensures the specific positioning of the nitroxide moiety at the mitochondrial membrane interface and maximizes their protective effects. These new insights into the structure-activity relationships of nitroxide-peptide and -peptide isostere conjugates are instrumental for development of new mechanism-based therapeutically effective agents.
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Affiliation(s)
- Jianfei Jiang
- Department of Environmental and Occupational Health, University of Pittsburgh, Pittsburgh, PA 15219, USA
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Toler SM, Noe D, Sharma A. Selective enhancement of cellular oxidative stress by chloroquine: implications for the treatment of glioblastoma multiforme. Neurosurg Focus 2006; 21:E10. [PMID: 17341043 DOI: 10.3171/foc.2006.21.6.1] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Chloroquine is used in the treatment of malaria, a disease caused by infection with the parasite Plasmodium. Although chloroquine appears to possess diverse pharmacological activity, its plasmodicidal activity results from augmentation of parasite oxidative stress. Chloroquine also appears to augment oxidative stress in metabolically active mammalian cells, including human astroglial cells. The authors propose that chloroquine may augment oxidative stress induced by radiotherapy in the treatment of glioblastoma multiforme, enhancing therapeutic efficacy. Such an effect would be consistent with the known pharmacological effects of chloroquine observed in Plasmodium. Other selective redox agents, such as tempol and artemisinin, should be investigated clinically for therapeutic benefit when coadministered with combined radio- and chemotherapy for cancer.
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Affiliation(s)
- Steven M Toler
- Department of Clinical Pharmacology, Pfizer, Incorporated, 50 Pequot Avenue, New London, Connecticut 06320, USA.
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Gariboldi MB, Terni F, Ravizza R, Meschini S, Marra M, Condello M, Arancia G, Monti E. The nitroxide Tempol modulates anthracycline resistance in breast cancer cells. Free Radic Biol Med 2006; 40:1409-18. [PMID: 16631531 DOI: 10.1016/j.freeradbiomed.2005.12.011] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/20/2005] [Revised: 12/09/2005] [Accepted: 12/12/2005] [Indexed: 01/19/2023]
Abstract
The occurrence of multidrug resistance (MDR) is the major obstacle to successful anthracycline-based cancer chemotherapy. In the present study, we assessed the effects of Tempol (4-hydroxy-2,2,6,6-tetramethylpiperidine-N-oxyl, TPL), a piperidine nitroxide with growth-inhibitory properties in tumor cell lines, on a number of molecular mechanisms involved in the resistance of human breast adenocarcinoma cell lines to doxorubicin (DOX). Cytotoxicity studies in MCF-7 wildtype and their MDR variant MCF-7 Adr(R) cells showed a synergistic effect between TPL and DOX when exposure to TPL preceded or was simultaneous with DOX treatment in MCF-7 Adr(R) cells. This effect of TPL seems to be due in part to its ability to increase peroxide levels and to deplete cellular glutathione pools. In addition, TPL increased DOX accumulation in MCF-7 Adr(R) cells by interfering with P-glycoprotein-mediated DOX efflux, as evidenced using a specific antibody that recognizes the active form of the protein. TPL was also found to affect the expression levels of proteins involved in response to drug treatment (e.g., p53, bcl2, bax, p21). Taken together, our results indicate that TPL is a potential new agent that may improve the clinical effect of DOX in tumors exhibiting a MDR phenotype.
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Kobayashi N, DeLano FA, Schmid-Schönbein GW. Oxidative Stress Promotes Endothelial Cell Apoptosis and Loss of Microvessels in the Spontaneously Hypertensive Rats. Arterioscler Thromb Vasc Biol 2005; 25:2114-21. [PMID: 16037565 DOI: 10.1161/01.atv.0000178993.13222.f2] [Citation(s) in RCA: 97] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
OBJECTIVE Endothelial cell apoptosis caused by oxidative stress may lead to the loss of microvessels (rarefaction) in hypertension. We examine here the effects of antioxidants on cell apoptosis and rarefaction. METHODS AND RESULTS The juvenile spontaneously hypertensive rats (SHR) and normotensive Wistar-Kyoto (WKY) rats were treated with superoxide scavengers, Tempol or Tiron, during growth. After the treatment, oxidative stress status, endothelial cell apoptosis rate, and microvessel length density in skeletal muscle and mesentery were evaluated in comparison with age-matched controls. Untreated 16-week-old SHR had higher oxidative stress (P<0.01) and cell apoptosis rate (P<0.05) and lower microvessel length density (371+/-17 mm/mm3 [P<0.01]) compared with age-matched WKY rats (435+/-15 mm/mm3). In the SHR, but not in WKY rats, systemically applied antioxidants attenuated oxidative stress and cell apoptosis rate (P<0.05 versus untreated controls) and prevented the loss of microvessels (411+/-15 mm/mm3 for Tempol [P<0.01 versus untreated control] and 399+/-17 mm/mm3 for Tiron [P<0.05]). CONCLUSIONS Antioxidant treatment with cell-permeable superoxide scavengers inhibits endothelial cell apoptosis and prevents microvessel rarefaction in the SHR during growth.
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Affiliation(s)
- Nobuhiko Kobayashi
- Department of Bioengineering, Whitaker Institute of Biomedical Engineering, University of California, San Diego, La Jolla, CA 92093-0412, USA
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Suy S, Mitchell JB, Samuni A, Mueller S, Kasid U. Nitroxide tempo, a small molecule, induces apoptosis in prostate carcinoma cells and suppresses tumor growth in athymic mice. Cancer 2005; 103:1302-13. [PMID: 15685617 DOI: 10.1002/cncr.20898] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
BACKGROUND In previous studies, nitroxide tempo (2, 2, 6, 6-tetramethyl-piperidine-1-oxyl), a small molecule, induced cell death in cancer cells. The current study examined the antineoplastic properties of tempo in the human hormone-dependent/hormone-independent prostate carcinoma models (LNCaP, DU-145, and PC-3). METHODS The apoptotic effects of tempo were examined by the flow cytometric analysis of cells labeled with fluorescein isothiocyanate-conjugated annexin-V, and by electron microscopy. Enzymatic assays were performed to measure the activities of 2 cysteine proteases, i.e., caspase-9 and caspase-3, in tempo-treated cells. The effects of tempo on cell proliferation and on cell cycle distribution profiles were measured by the flow cytometric assay using immunofluorescent staining of incorporated 5'-bromo-2'-deoxyuridine (BrdU) coupled with 7-amino-actinomycin D (7-AAD) staining of total DNA. The number of proliferating cells was also determined independently by enzyme-linked immunosorbent assay using chemiluminescent detection of incorporated BrdU. Subcutaneous growth of human prostate carcinoma in athymic mice was monitored after intratumoral administration of tempo into tumor-bearing mice. In addition, cell viability assays were performed to compare the cytotoxic effect of a combination of doxorubicin or mitoxantrone and tempo with single agents. RESULTS Tempo treatment of prostate carcinoma cells caused a significant increase in the number of apoptotic cells compared with control groups (tempo, 2.5 mM, 24 hours: DU-145, approximately 3.4-fold; PC-3, approximately 6-7-fold; tempo 1 mM, 24 hours: LNCaP, approximately 12-fold). Tempo-induced loss of cell viability was blocked partially or completely after pretreatment of cells with actinomycin-D or cycloheximide, suggesting a de novo macromolecule synthesis-dependent mechanism of cell death. Electron microscopy revealed aggregation and marginalization of chromatin in the nuclei of a large number of tempo-treated LNCaP cells. Tempo treatment of LNCaP cells resulted in enhanced activities of caspase-9 (tempo, 5 mM, 15 hours: approximately 2-fold) and caspase-3 (tempo, 2.5 mM, 24 hours: approximately 12-fold). Tempo treatment also led to an enhanced number of cells in G2/M phase of the cell cycle (tempo, 5.0 mM, 24 hours: DU-145, approximately 1.6-fold; PC-3, approximately 1.5-fold; LNCaP, approximately 5.3-fold), and decreased BrdU incorporation indicative of a decline in the number of proliferating cells (tempo, 2.5 mM, 24 or 48 hours; DU-145, approximately 2-3-fold; PC-3, approximately 1.2-fold; LNCaP, approximately 5-10-fold). Administration of tempo into LNCaP tumor-bearing mice resulted in a significant inhibition of tumor growth (percent initial tumor volume [Day 30, n = 4]: vehicle, 845.35 +/- 272.83; tempo, 9.72 +/- 9.72; tempo vs. vehicle, P < 0.02). In hormone-refractory prostate carcinoma cells, a combination of relatively low doses of tempo and doxorubicin or mitoxantrone caused enhanced cytotoxicity as compared with single agents. CONCLUSIONS These data demonstrated that nitroxide tempo induced apoptosis and activated a caspase-mediated signaling pathway in prostate carcinoma cells. Tempo treatment also caused cell cycle arrest in G2/M phase and decreased the number of proliferating cells (S phase). Tempo treatment of tumor-bearing mice led to inhibition of tumor growth, suggesting that tempo is a novel member of the small-molecule family of antineoplastic agents.
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Affiliation(s)
- Simeng Suy
- Department of Radiation Medicine, Biochemistry and Molecular Biology, Georgetown University Medical Center, Washington, DC 20007, USA
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Cook JA, Gius D, Wink DA, Krishna MC, Russo A, Mitchell JB. Oxidative stress, redox, and the tumor microenvironment. Semin Radiat Oncol 2004; 14:259-66. [PMID: 15254869 DOI: 10.1016/j.semradonc.2004.04.001] [Citation(s) in RCA: 198] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Cellular metabolism is critical for the generation of energy in biological systems; however, as a result of electron transfer reactions, reactive oxygen species (ROS) are generated in aerobic cells. Although low amounts of ROS are easily tolerated by the cell, abnormally high levels of ROS induce oxidative stress. ROS are also produced after exposure to ionizing radiation, selected chemotherapeutic agents, hyperthermia, inhibition of antioxidant enzymes, or depletion of cellular reductants such as NADPH and glutathione. Oxidative stress such as ionizing radiation produces a variety of highly reactive free radicals that damage cells, initiate signal transduction pathways, and alter gene expression. Cells are capable of countering the effects of oxidative stress by virtue of a complex redox buffering system. With respect to the radiation treatment of cancer, components of the cellular redox armamentarium may be targeted to enhance cell killing in the case of tumors and/or protection in the case of normal tissues.
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Affiliation(s)
- John A Cook
- Radiation Biology Branch, Center for Cancer Research, National Cancer Institute, Bethesda, MD 20892, USA
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Samuni Y, Gamson J, Samuni A, Yamada K, Russo A, Krishna MC, Mitchell JB. Factors influencing nitroxide reduction and cytotoxicity in vitro. Antioxid Redox Signal 2004; 6:587-95. [PMID: 15130285 DOI: 10.1089/152308604773934341] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Nitroxides have been shown to be effective antioxidants, radiation protectors, and redox-active probes for functional electron paramagnetic resonance (EPR) imaging. More recently, the nitroxide 4-hydroxy-2,2,6,6-tetramethylpiperidinyl-N-oxyl (Tempol) has been shown to exert differential cytotoxicity to tumor compared with normal cell counterparts. Nitroxides are readily reduced in tissues to their respective hydroxylamines, which exhibit less cytotoxicity in vitro and do not provide radiation protection or an EPR-detectable signal for imaging. In order to better understand factors that influence nitroxide reduction, the rate of reduction of Tempol in mouse and human cell lines and in primary cultures of tumor cells was measured using EPR spectroscopy. Additionally, the cytotoxicity of high concentrations of Tempol and the hydroxylamine of Tempol (Tempol-H) was evaluated in wild-type and glucose-6-phosphate dehydrogenase (G6PD)-deficient Chinese hamster ovary cells. The results show that in general Tempol was reduced at a faster rate when cells were under hypoxic compared with aerobic conditions. Neither depletion of intracellular glutathione nor treatment of cells with sodium cyanide influenced Tempol reduction rates. G6PD-deficient cells were found to reduce Tempol at a significantly slower rate than wild-type cells. Likewise, Tempol-induced cytotoxicity was markedly less for G6PD-deficient cells compared with wild-type cells. Tempol-H exhibited no cytotoxicity to either cell type. Tempol-mediated cytotoxicity was enhanced by glutathione depletion and inhibition of 6-phosphogluconate dehydrogenase in wild-type cells, but was unaltered in G6PD-deficient cells. Collectively, the results indicate that while the bioreduction of Tempol can be influenced by a number of factors, the hexose monophosphate shunt appears to be involved in both nitroxide reduction as well as cytotoxicity induced by high levels of exposure to Tempol.
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Affiliation(s)
- Yuval Samuni
- Radiation Biology Branch, Center for Cancer Research, National Cancer Institute, Bethesda, MD 20892, USA
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