1
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Xu Y, Lv J, Kong C, Li Y, Wang K, Shen N, Tang Z. A novel hypoxia‐activated polymeric
Tirapazamine
derivative for enhanced antitumor therapy. JOURNAL OF POLYMER SCIENCE 2023. [DOI: 10.1002/pol.20220702] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- Yajun Xu
- CAS Key Laboratory of Polymer Ecomaterials Changchun Institute of Applied Chemistry, Chinese Academy of Sciences Changchun P. R. China
- College of Applied Chemistry and Engineering University of Science and Technology of China Hefei P. R. China
| | - Jianlin Lv
- CAS Key Laboratory of Polymer Ecomaterials Changchun Institute of Applied Chemistry, Chinese Academy of Sciences Changchun P. R. China
- College of Applied Chemistry and Engineering University of Science and Technology of China Hefei P. R. China
| | - Chaoying Kong
- CAS Key Laboratory of Polymer Ecomaterials Changchun Institute of Applied Chemistry, Chinese Academy of Sciences Changchun P. R. China
- College of Applied Chemistry and Engineering University of Science and Technology of China Hefei P. R. China
| | - Yanran Li
- CAS Key Laboratory of Polymer Ecomaterials Changchun Institute of Applied Chemistry, Chinese Academy of Sciences Changchun P. R. China
- College of Applied Chemistry and Engineering University of Science and Technology of China Hefei P. R. China
| | - Kun Wang
- CAS Key Laboratory of Polymer Ecomaterials Changchun Institute of Applied Chemistry, Chinese Academy of Sciences Changchun P. R. China
| | - Na Shen
- CAS Key Laboratory of Polymer Ecomaterials Changchun Institute of Applied Chemistry, Chinese Academy of Sciences Changchun P. R. China
| | - Zhaohui Tang
- CAS Key Laboratory of Polymer Ecomaterials Changchun Institute of Applied Chemistry, Chinese Academy of Sciences Changchun P. R. China
- College of Applied Chemistry and Engineering University of Science and Technology of China Hefei P. R. China
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2
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Ding Z, Guo Z, Zheng Y, Wang Z, Fu Q, Liu Z. Radiotherapy Reduces N-Oxides for Prodrug Activation in Tumors. J Am Chem Soc 2022; 144:9458-9464. [PMID: 35594148 DOI: 10.1021/jacs.2c02521] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Precisely activating chemotherapeutic prodrugs in a tumor-selective manner is an ideal way to cure cancers without causing systemic toxicities. Although many efforts have been made, developing spatiotemporally controllable activation methods is still an unmet challenge. Here, we report a novel prodrug activation strategy using radiotherapy (X-ray). Due to its precision and deep tissue penetration, X-ray matches the need for altering molecules in tumors through water radiolysis. We first demonstrated that N-oxides can be effectively reduced by hydrated electrons (e-aq) generated from radiation both in tubes and living cells. A screening is performed to investigate the structure-reduction relationship and mechanism of the e-aq-mediated reductions. We then apply the strategy to activate N-oxide prodrugs. The anticancer drug camptothecin (CPT)-based N-oxide prodrug shows a remarkable anticancer effect upon activation by radiotherapy. This radiation-induced in vivo chemistry may enable versatile designs of radiotherapy-activated prodrugs, which are of remarkable clinical relevance, as over 50% of cancer patients take radiotherapy.
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Affiliation(s)
- Zexuan Ding
- Beijing National Laboratory for Molecular Sciences, Radiochemistry and Radiation Chemistry Key Laboratory of Fundamental Science, NMPA Key Laboratory for Research and Evaluation of Radiopharmaceuticals, Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China.,Peking University-Tsinghua University Center for Life Sciences, Peking University, Beijing 100871, China
| | - Zhibin Guo
- Beijing National Laboratory for Molecular Sciences, Radiochemistry and Radiation Chemistry Key Laboratory of Fundamental Science, NMPA Key Laboratory for Research and Evaluation of Radiopharmaceuticals, Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
| | - Yuedan Zheng
- Beijing National Laboratory for Molecular Sciences, Radiochemistry and Radiation Chemistry Key Laboratory of Fundamental Science, NMPA Key Laboratory for Research and Evaluation of Radiopharmaceuticals, Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
| | - Ziyang Wang
- Beijing National Laboratory for Molecular Sciences, Radiochemistry and Radiation Chemistry Key Laboratory of Fundamental Science, NMPA Key Laboratory for Research and Evaluation of Radiopharmaceuticals, Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
| | - Qunfeng Fu
- Beijing National Laboratory for Molecular Sciences, Radiochemistry and Radiation Chemistry Key Laboratory of Fundamental Science, NMPA Key Laboratory for Research and Evaluation of Radiopharmaceuticals, Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
| | - Zhibo Liu
- Beijing National Laboratory for Molecular Sciences, Radiochemistry and Radiation Chemistry Key Laboratory of Fundamental Science, NMPA Key Laboratory for Research and Evaluation of Radiopharmaceuticals, Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China.,Peking University-Tsinghua University Center for Life Sciences, Peking University, Beijing 100871, China
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3
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Spin Trapping Hydroxyl and Aryl Radicals of One-Electron Reduced Anticancer Benzotriazine 1,4-Dioxides. Molecules 2022; 27:molecules27030812. [PMID: 35164077 PMCID: PMC8840461 DOI: 10.3390/molecules27030812] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Revised: 01/19/2022] [Accepted: 01/21/2022] [Indexed: 02/06/2023] Open
Abstract
Hypoxia in tumors results in resistance to both chemotherapy and radiotherapy treatments but affords an environment in which hypoxia-activated prodrugs (HAP) are activated upon bioreduction to release targeted cytotoxins. The benzotriazine 1,4-di-N-oxide (BTO) HAP, tirapazamine (TPZ, 1), has undergone extensive clinical evaluation in combination with radiotherapy to assist in the killing of hypoxic tumor cells. Although compound 1 did not gain approval for clinical use, it has spurred on the development of other BTOs, such as the 3-alkyl analogue, SN30000, 2. There is general agreement that the cytotoxin(s) from BTOs arise from the one-electron reduced form of the compounds. Identifying the cytotoxic radicals, and whether they play a role in the selective killing of hypoxic tumor cells, is important for continued development of the BTO class of anticancer prodrugs. In this study, nitrone spin-traps, combined with electron spin resonance, give evidence for the formation of aryl radicals from compounds 1, 2 and 3-phenyl analogues, compounds 3 and 4, which form carbon C-centered radicals. In addition, high concentrations of DEPMPO (5-(diethoxyphosphoryl)-5-methyl-1-pyrroline N-oxide) spin-trap the •OH radical. The combination of spin-traps with high concentrations of DMSO and methanol also give evidence for the involvement of strongly oxidizing radicals. The failure to spin-trap methyl radicals with PBN (N-tert-butylphenylnitrone) on the bioreduction of compound 2, in the presence of DMSO, implies that free •OH radicals are not released from the protonated radical anions of compound 2. The spin-trapping of •OH radicals by high concentrations of DEPMPO, and the radical species arising from DMSO and methanol give both direct and indirect evidence for the scavenging of •OH radicals that are involved in an intramolecular process. Hypoxia-selective cytotoxicity is not related to the formation of aryl radicals from the BTO compounds as they are associated with high aerobic cytotoxicity.
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4
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Song X, Deng J, Zhang J. Ultra‐low degree of polymerization polyvinyl alcohol products prepared by oxidative chain scission: Method and mechanism. J Appl Polym Sci 2021. [DOI: 10.1002/app.50549] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Xianni Song
- Institude of Chemical Material China Academy of Engineering Physics Mianyang China
- The State Key Laboratory of Polymer Materials Engineering Polymer Research Institute of Sichuan University Chengdu China
| | - Jianguo Deng
- Institude of Chemical Material China Academy of Engineering Physics Mianyang China
| | - Junhua Zhang
- The State Key Laboratory of Polymer Materials Engineering Polymer Research Institute of Sichuan University Chengdu China
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5
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Wang L, Chen M, Luo X, Fan Y, Zheng Z, He Z, Yin R, Meng T, Xu S, Pan Y, Su J, Du J, Zhang L, Tian X, Tian Y, Chen D, Ge H, Zhang N, Li P. Intramolecular Annulation of Gossypol by Laccase to Produce Safe Cottonseed Protein. Front Chem 2020; 8:583176. [PMID: 33335884 PMCID: PMC7736553 DOI: 10.3389/fchem.2020.583176] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Accepted: 10/28/2020] [Indexed: 11/13/2022] Open
Abstract
The presence of the phenol gossypol has severely limited the utilization of cottonseed meal and oil in the food and animal feed industries. Highly efficient means of biodegradation of gossypol and an understanding of the cytotoxicity of its degradation products remain outside current knowledge and are of universal interest. In this work, we showed for the first time that laccase can catalyze the intramolecular annulation of the aldehyde and hydroxyl groups of gossypol for the o-semiquinone radical and originate the released ·OH radical. It was further found that the oxidation of aldehyde groups significantly decreases reproductive toxicity and hepatotoxicity. These results indicate a novel detoxification pathway for gossypol and reveal the crucial role played by radical species in cyclization. This discovery could facilitate the development of safe, convenient, and low-cost industrial methods for the detoxification of cotton protein and oil resources.
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Affiliation(s)
- Lin Wang
- Research Center for Translational Medicine at Shanghai East Hospital, School of Life Sciences and Technology, Tongji University, Shanghai, China.,School of Life Sciences, Anhui University, Hefei, China
| | - Ming Chen
- Chinese Academy of Sciences Key Laboratory of Microscale Magnetic Resonance, Department of Modern Physics, University of Science and Technology of China, Hefei, China
| | - Xuecai Luo
- School of Life Sciences, Anhui University, Hefei, China
| | - Yanan Fan
- School of Life Sciences, Anhui University, Hefei, China
| | - Zai Zheng
- School of Life Sciences, Anhui University, Hefei, China
| | - Zongqin He
- School of Life Sciences, Anhui University, Hefei, China
| | - Ruochun Yin
- School of Life Sciences, Anhui University, Hefei, China
| | - Tao Meng
- School of Life Sciences, Anhui University, Hefei, China
| | - Shuyang Xu
- School of Life Sciences, Anhui University, Hefei, China
| | - Yu Pan
- School of Life Sciences, Anhui University, Hefei, China
| | - Jihu Su
- Chinese Academy of Sciences Key Laboratory of Microscale Magnetic Resonance, Department of Modern Physics, University of Science and Technology of China, Hefei, China
| | - Jiangfeng Du
- Chinese Academy of Sciences Key Laboratory of Microscale Magnetic Resonance, Department of Modern Physics, University of Science and Technology of China, Hefei, China
| | - Liang Zhang
- National Engineering Laboratory for Cereal Fermentation Technology, Jiangnan University, Wuxi, China
| | - Xiaohe Tian
- School of Life Sciences, Anhui University, Hefei, China
| | - Yupeng Tian
- College of Chemistry and Chemical Engineering, Anhui University, Hefei, China
| | - Dongdong Chen
- School of Life Sciences, Anhui University, Hefei, China
| | - Honghua Ge
- School of Life Sciences, Anhui University, Hefei, China
| | - Nannan Zhang
- School of Life Sciences, Anhui University, Hefei, China
| | - Ping Li
- Research Center for Translational Medicine at Shanghai East Hospital, School of Life Sciences and Technology, Tongji University, Shanghai, China
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6
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Subcellular Location of Tirapazamine Reduction Dramatically Affects Aerobic but Not Anoxic Cytotoxicity. Molecules 2020; 25:molecules25214888. [PMID: 33105798 PMCID: PMC7660101 DOI: 10.3390/molecules25214888] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2020] [Revised: 10/20/2020] [Accepted: 10/20/2020] [Indexed: 11/16/2022] Open
Abstract
Hypoxia is an adverse prognostic feature of solid cancers that may be overcome with hypoxia-activated prodrugs (HAPs). Tirapazamine (TPZ) is a HAP which has undergone extensive clinical evaluation in this context and stimulated development of optimized analogues. However the subcellular localization of the oxidoreductases responsible for mediating TPZ-dependent DNA damage remains unclear. Some studies conclude only nuclear-localized oxidoreductases can give rise to radical-mediated DNA damage and thus cytotoxicity, whereas others identify a broader role for endoplasmic reticulum and cytosolic oxidoreductases, indicating the subcellular location of TPZ radical formation is not a critical requirement for DNA damage. To explore this question in intact cells we engineered MDA-231 breast cancer cells to express the TPZ reductase human NADPH: cytochrome P450 oxidoreductase (POR) harboring various subcellular localization sequences to guide this flavoenzyme to the nucleus, endoplasmic reticulum, cytosol or inner surface of the plasma membrane. We show that all POR variants are functional, with differences in rates of metabolism reflecting enzyme expression levels rather than intracellular TPZ concentration gradients. Under anoxic conditions, POR expression in all subcellular compartments increased the sensitivity of the cells to TPZ, but with a fall in cytotoxicity per unit of metabolism (termed ‘metabolic efficiency’) when POR is expressed further from the nucleus. However, under aerobic conditions a much larger increase in cytotoxicity was observed when POR was directed to the nucleus, indicating very high metabolic efficiency. Consequently, nuclear metabolism results in collapse of hypoxic selectivity of TPZ, which was further magnified to the point of reversing O2 dependence (oxic > hypoxic sensitivity) by employing a DNA-affinic TPZ analogue. This aerobic hypersensitivity phenotype was partially rescued by cellular copper depletion, suggesting the possible involvement of Fenton-like chemistry in generating short-range effects mediated by the hydroxyl radical. In addition, the data suggest that under aerobic conditions reoxidation strictly limits the TPZ radical diffusion range resulting in site-specific cytotoxicity. Collectively these novel findings challenge the purported role of intra-nuclear reductases in orchestrating the hypoxia selectivity of TPZ.
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7
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Novel combination therapy for melanoma induces apoptosis via a gap junction positive feedback mechanism. Oncotarget 2020; 11:3443-3458. [PMID: 32973969 PMCID: PMC7500108 DOI: 10.18632/oncotarget.27732] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Accepted: 08/05/2020] [Indexed: 11/25/2022] Open
Abstract
Metastatic melanoma cells overexpressing gap junctions were assayed for their ability to propagate cell death by a novel combination therapy that generates reactive oxygen species (ROS) by both 1) non-thermal plasma (NTP) and 2) tirapazamine (TPZ) under hypoxic conditions. Results demonstrate additive-to-synergistic effects of combination therapy compared to each agent individually. NTP induces highly localized cell death in target areas whereas TPZ partially reduces viability over the total surface area. However, when high gap junction expression was induced in melanoma cells, effects of combination NTP+TPZ therapy was augmented, spreading cell death across the entire plate. Similarly, in vivo studies of human metastatic melanoma in a mouse tumor model demonstrate that the combined effect of NTP+TPZ causes a 90% reduction in tumor volume, specifically in the model expressing gap junctions. Treatment with NTP+TPZ increases gene expression in the apoptotic pathway and oxidative stress while decreasing genes related to cell migration. Immune response was also elicited through differential regulation of cytokines and chemokines, suggesting potential for this therapy to induce a cytotoxic immune response with fewer side effects than current therapies. Interestingly, the gap junction protein, Cx26 was upregulated following treatment with NTP+TPZ and these gap junctions were shown to maintain functionality during the onset of treatment. Therefore, we propose that gap junctions both increase the efficacy of NTP+TPZ and perpetuate a positive feedback mechanism of gap junction expression and tumoricidal activity. Our unique approach to ROS induction in tumor cells with NTP+TPZ shows potential as a novel cancer treatment.
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8
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Hay MP, Shin HN, Wong WW, Sahimi WW, Vaz ATD, Yadav P, Anderson RF, Hicks KO, Wilson WR. Benzotriazine Di-Oxide Prodrugs for Exploiting Hypoxia and Low Extracellular pH in Tumors. Molecules 2019; 24:E2524. [PMID: 31295864 PMCID: PMC6680510 DOI: 10.3390/molecules24142524] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2019] [Revised: 07/05/2019] [Accepted: 07/06/2019] [Indexed: 12/31/2022] Open
Abstract
Extracellular acidification is an important feature of tumor microenvironments but has yet to be successfully exploited in cancer therapy. The reversal of the pH gradient across the plasma membrane in cells that regulate intracellular pH (pHi) has potential to drive the selective uptake of weak acids at low extracellular pH (pHe). Here, we investigate the dual targeting of low pHe and hypoxia, another key feature of tumor microenvironments. We prepared eight bioreductive prodrugs based on the benzotriazine di-oxide (BTO) nucleus by appending alkanoic or aminoalkanoic acid sidechains. The BTO acids showed modest selectivity for both low pHe (pH 6.5 versus 7.4, ratios 2 to 5-fold) and anoxia (ratios 2 to 8-fold) in SiHa and FaDu cell cultures. Related neutral BTOs were not selective for acidosis, but had greater cytotoxic potency and hypoxic selectivity than the BTO acids. Investigation of the uptake and metabolism of representative BTO acids confirmed enhanced uptake at low pHe, but lower intracellular concentrations than expected for passive diffusion. Further, the modulation of intracellular reductase activity and competition by the cell-excluded electron acceptor WST-1 suggests that the majority of metabolic reductions of BTO acids occur at the cell surface, compromising the engagement of the resulting free radicals with intracellular targets. Thus, the present study provides support for designing bioreductive prodrugs that exploit pH-dependent partitioning, suggesting, however, that that the approach should be applied to prodrugs with obligate intracellular activation.
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Affiliation(s)
- Michael P Hay
- Auckland Cancer Society Research Centre, School of Medical Sciences, Faculty of Medical and Health Sciences, University of Auckland, Auckland 1142, New Zealand
- Maurice Wilkins Centre for Molecular Biodiscovery, University of Auckland, Symonds St, Auckland 1142, New Zealand
| | - Hong Nam Shin
- Auckland Cancer Society Research Centre, School of Medical Sciences, Faculty of Medical and Health Sciences, University of Auckland, Auckland 1142, New Zealand
| | - Way Wua Wong
- Auckland Cancer Society Research Centre, School of Medical Sciences, Faculty of Medical and Health Sciences, University of Auckland, Auckland 1142, New Zealand
| | - Wan Wan Sahimi
- School of Chemical Sciences, University of Auckland, Auckland 1142, New Zealand
| | - Aaron T D Vaz
- Auckland Cancer Society Research Centre, School of Medical Sciences, Faculty of Medical and Health Sciences, University of Auckland, Auckland 1142, New Zealand
| | - Pooja Yadav
- Auckland Cancer Society Research Centre, School of Medical Sciences, Faculty of Medical and Health Sciences, University of Auckland, Auckland 1142, New Zealand
| | - Robert F Anderson
- Auckland Cancer Society Research Centre, School of Medical Sciences, Faculty of Medical and Health Sciences, University of Auckland, Auckland 1142, New Zealand
- Maurice Wilkins Centre for Molecular Biodiscovery, University of Auckland, Symonds St, Auckland 1142, New Zealand
- School of Chemical Sciences, University of Auckland, Auckland 1142, New Zealand
| | - Kevin O Hicks
- Auckland Cancer Society Research Centre, School of Medical Sciences, Faculty of Medical and Health Sciences, University of Auckland, Auckland 1142, New Zealand
- Maurice Wilkins Centre for Molecular Biodiscovery, University of Auckland, Symonds St, Auckland 1142, New Zealand
| | - William R Wilson
- Auckland Cancer Society Research Centre, School of Medical Sciences, Faculty of Medical and Health Sciences, University of Auckland, Auckland 1142, New Zealand.
- Maurice Wilkins Centre for Molecular Biodiscovery, University of Auckland, Symonds St, Auckland 1142, New Zealand.
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Wang Y, Shang W, Niu M, Tian J, Xu K. Hypoxia-active nanoparticles used in tumor theranostic. Int J Nanomedicine 2019; 14:3705-3722. [PMID: 31190820 PMCID: PMC6535445 DOI: 10.2147/ijn.s196959] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2018] [Accepted: 04/04/2019] [Indexed: 12/17/2022] Open
Abstract
Hypoxia is a hallmark of malignant tumors and often correlates with increasing tumor aggressiveness and poor treatment outcomes. Therefore, early diagnosis and effective killing of hypoxic tumor cells are crucial for successful tumor control. There has been a surge of interdisciplinary research aimed at developing functional molecules and nanomaterials that can be used to noninvasively image and efficiently treat hypoxic tumors. These mainly include hypoxia-active nanoparticles, anti-hypoxia agents, and agents that target biomarkers of tumor hypoxia. Hypoxia-active nanoparticles have been intensively investigated and have demonstrated advanced effects on targeting tumor hypoxia. In this review, we present an overview of the reports published to date on hypoxia-activated prodrugs and their nanoparticle forms used in tumor-targeted therapy. Hypoxia-responsive nanoparticles are inactive during blood circulation and normal physiological conditions but are activated by hypoxia once they extravasate into the hypoxic tumor microenvironment. Their use can enhance the efficiency of tumor chemotherapy, radiotherapy, fluorescence and photoacoustic intensity, and other imaging and therapeutic strategies. By targeting the broad habitats of tumors, rather than tumor-specific receptors, this strategy has the potential to overcome the problem of tumor heterogeneity and could be used to design diagnostic and therapeutic nanoparticles for a broad range of solid tumors.
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Affiliation(s)
- Yaqin Wang
- Department of Interventional Radiology, The First Affiliated Hospital of China Medical University, Shenyang, People's Republic of China.,Chinese Academy of Sciences Key Laboratory of Molecular Imaging, Institute of Automation, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
| | - Wenting Shang
- Chinese Academy of Sciences Key Laboratory of Molecular Imaging, Institute of Automation, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
| | - Meng Niu
- Department of Interventional Radiology, The First Affiliated Hospital of China Medical University, Shenyang, People's Republic of China
| | - Jie Tian
- Chinese Academy of Sciences Key Laboratory of Molecular Imaging, Institute of Automation, Chinese Academy of Sciences, Beijing 100190, People's Republic of China.,Institute of Medical Interdisciplinary Innovation, Beihang University, Beijing, 100080, People's Republic of China
| | - Ke Xu
- Department of Interventional Radiology, The First Affiliated Hospital of China Medical University, Shenyang, People's Republic of China
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10
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Shen X, Gates KS. Enzyme-Activated Generation of Reactive Oxygen Species from Heterocyclic N-Oxides under Aerobic and Anaerobic Conditions and Its Relevance to Hypoxia-Selective Prodrugs. Chem Res Toxicol 2019; 32:348-361. [PMID: 30817135 DOI: 10.1021/acs.chemrestox.9b00036] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Enzymatic one-electron reduction of heterocyclic N-oxides can lead to the intracellular generation of reactive oxygen species via several different chemical pathways. These reactions may be relevant to hypoxia-selective anticancer drugs, antimicrobial agents, and unwanted toxicity of heterocylic nitrogen compounds.
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11
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Jackson RK, Liew LP, Hay MP. Overcoming Radioresistance: Small Molecule Radiosensitisers and Hypoxia-activated Prodrugs. Clin Oncol (R Coll Radiol) 2019; 31:290-302. [PMID: 30853148 DOI: 10.1016/j.clon.2019.02.004] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2019] [Accepted: 02/12/2019] [Indexed: 12/25/2022]
Abstract
The role of hypoxia in radiation resistance is well established and many approaches to overcome hypoxia in tumours have been explored, with variable success. Two small molecule strategies for targeting hypoxia have dominated preclinical and clinical efforts. One approach has been the use of electron-affinic nitroheterocycles as oxygen-mimetic sensitisers. These agents are best exemplified by the 5-nitroimidazole nimorazole, which has limited use in conjunction with radiotherapy in head and neck squamous cell carcinoma. The second approach seeks to leverage tumour hypoxia as a tumour-specific address for hypoxia-activated prodrugs. These prodrugs are selectively activated by reductases under hypoxia to release cytotoxins, which in some instances may diffuse to kill surrounding oxic tumour tissue. A number of these hypoxia-activated prodrugs have been examined in clinical trial and the merits and shortcomings of recent examples are discussed. There has been an evolution from delivering DNA-interactive cytotoxins to molecularly targeted agents. Efforts to implement these strategies clinically continue today, but success has been elusive. Several issues have been identified that compromised these clinical campaigns. A failure to consider the extravascular transport and the micropharmacokinetic properties of the prodrugs has reduced efficacy. One key element for these 'targeted' approaches is the need to co-develop biomarkers to identify appropriate patients. Hypoxia-activated prodrugs require biomarkers for hypoxia, but also for appropriate activating reductases in tumours, as well as markers of intrinsic sensitivity to the released drug. The field is still evolving and changes in radiation delivery and the impact of immune-oncology will provide fertile ground for future innovation.
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Affiliation(s)
- R K Jackson
- Auckland Cancer Society Research Centre, School of Medical Sciences, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
| | - L P Liew
- Auckland Cancer Society Research Centre, School of Medical Sciences, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand; Maurice Wilkins Centre for Molecular Biodiscovery, University of Auckland, Auckland, New Zealand
| | - M P Hay
- Auckland Cancer Society Research Centre, School of Medical Sciences, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand; Maurice Wilkins Centre for Molecular Biodiscovery, University of Auckland, Auckland, New Zealand.
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12
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Sharma A, Arambula JF, Koo S, Kumar R, Singh H, Sessler JL, Kim JS. Hypoxia-targeted drug delivery. Chem Soc Rev 2019; 48:771-813. [PMID: 30575832 PMCID: PMC6361706 DOI: 10.1039/c8cs00304a] [Citation(s) in RCA: 303] [Impact Index Per Article: 60.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Hypoxia is a state of low oxygen tension found in numerous solid tumours. It is typically associated with abnormal vasculature, which results in a reduced supply of oxygen and nutrients, as well as impaired delivery of drugs. The hypoxic nature of tumours often leads to the development of localized heterogeneous environments characterized by variable oxygen concentrations, relatively low pH, and increased levels of reactive oxygen species (ROS). The hypoxic heterogeneity promotes tumour invasiveness, metastasis, angiogenesis, and an increase in multidrug-resistant proteins. These factors decrease the therapeutic efficacy of anticancer drugs and can provide a barrier to advancing drug leads beyond the early stages of preclinical development. This review highlights various hypoxia-targeted and activated design strategies for the formulation of drugs or prodrugs and their mechanism of action for tumour diagnosis and treatment.
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Affiliation(s)
- Amit Sharma
- Department of Chemistry, Korea University, Seoul, 02841, Korea.
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13
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Shen X, Laber CH, Sarkar U, Galazzi F, Johnson KM, Mahieu NG, Hillebrand R, Fuchs-Knotts T, Barnes CL, Baker GA, Gates KS. Exploiting the Inherent Photophysical Properties of the Major Tirapazamine Metabolite in the Development of Profluorescent Substrates for Enzymes That Catalyze the Bioreductive Activation of Hypoxia-Selective Anticancer Prodrugs. J Org Chem 2018; 83:3126-3131. [DOI: 10.1021/acs.joc.7b03035] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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14
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Gu Y, Chang TTA, Wang J, Jaiswal JK, Edwards D, Downes NJ, Liyanage HDS, Lynch CRH, Pruijn FB, Hickey AJR, Hay MP, Wilson WR, Hicks KO. Reductive Metabolism Influences the Toxicity and Pharmacokinetics of the Hypoxia-Targeted Benzotriazine Di-Oxide Anticancer Agent SN30000 in Mice. Front Pharmacol 2017; 8:531. [PMID: 28848445 PMCID: PMC5554537 DOI: 10.3389/fphar.2017.00531] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2017] [Accepted: 07/28/2017] [Indexed: 12/23/2022] Open
Abstract
3-(3-Morpholinopropyl)-7,8-dihydro-6H-indeno[5,6-e][1,2,4]triazine 1,4-dioxide (SN30- 000), an analog of the well-studied bioreductive prodrug tirapazamine (TPZ), has improved activity against hypoxic cells in tumor xenografts. However, little is known about its biotransformation in normal tissues. Here, we evaluate implications of biotransformation of SN30000 for its toxicokinetics in NIH-III mice. The metabolite profile demonstrated reduction to the 1-N-oxide (M14), oxidation of the morpholine side-chain (predominantly to the alkanoic acid M18) and chromophore, and subsequent glucuronidation. Plasma pharmacokinetics of SN30000 and its reduced metabolites was unaffected by the presence of HT29 tumor xenografts, indicating extensive reduction in normal tissues. This bioreductive metabolism, as modeled by hepatic S9 preparations, was strongly inhibited by oxygen indicating that it proceeds via the one-electron (radical) intermediate previously implicated in induction of DNA double strand breaks and cytotoxicity by SN30000. Plasma pharmacokinetics of SN30000 and M14 (but not M18) corresponded closely to the timing of reversible acute clinical signs (reduced mobility) and marked hypothermia (rectal temperature drop of ∼8°C at nadir following the maximum tolerated dose). Similar acute toxicity was elicited by dosing with TPZ or M14, although M14 did not induce the kidney and lung histopathology caused by SN30000. M14 also lacked antiproliferative potency in hypoxic cell cultures. In addition M14 showed much slower redox cycling than SN30000 in oxic cultures. Thus a non-bioreductive mechanism, mediated through M14, appears to be responsible for the acute toxicity of SN30000 while late toxicities are consistent with DNA damage resulting from its one-electron reduction. A two-compartment pharmacokinetic model, in which clearance of SN30000 is determined by temperature-dependent bioreductive metabolism to M14, was shown to describe the non-linear PK of SN30000 in mice. This study demonstrates the importance of non-tumor bioreductive metabolism in the toxicology and pharmacokinetics of benzotriazine di-oxides designed to target tumor hypoxia.
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Affiliation(s)
- Yongchuan Gu
- Experimental Therapeutics Group, Auckland Cancer Society Research Centre, School of Medical Sciences, The University of AucklandAuckland, New Zealand
| | - Tony T-A Chang
- Experimental Therapeutics Group, Auckland Cancer Society Research Centre, School of Medical Sciences, The University of AucklandAuckland, New Zealand
| | - Jingli Wang
- Experimental Therapeutics Group, Auckland Cancer Society Research Centre, School of Medical Sciences, The University of AucklandAuckland, New Zealand
| | - Jagdish K Jaiswal
- Experimental Therapeutics Group, Auckland Cancer Society Research Centre, School of Medical Sciences, The University of AucklandAuckland, New Zealand
| | - David Edwards
- Cancer Research Centre for Drug Development, Cancer Research UK (CRUK)London, United Kingdom
| | | | - H D Sarath Liyanage
- Experimental Therapeutics Group, Auckland Cancer Society Research Centre, School of Medical Sciences, The University of AucklandAuckland, New Zealand
| | - Courtney R H Lynch
- Experimental Therapeutics Group, Auckland Cancer Society Research Centre, School of Medical Sciences, The University of AucklandAuckland, New Zealand
| | - Frederik B Pruijn
- Experimental Therapeutics Group, Auckland Cancer Society Research Centre, School of Medical Sciences, The University of AucklandAuckland, New Zealand
| | - Anthony J R Hickey
- School of Biological Sciences, The University of AucklandAuckland, New Zealand
| | - Michael P Hay
- Experimental Therapeutics Group, Auckland Cancer Society Research Centre, School of Medical Sciences, The University of AucklandAuckland, New Zealand
| | - William R Wilson
- Experimental Therapeutics Group, Auckland Cancer Society Research Centre, School of Medical Sciences, The University of AucklandAuckland, New Zealand
| | - Kevin O Hicks
- Experimental Therapeutics Group, Auckland Cancer Society Research Centre, School of Medical Sciences, The University of AucklandAuckland, New Zealand
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15
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Sarkar U, Hillebrand R, Johnson KM, Cummings AH, Phung NL, Rajapakse A, Zhou H, Willis JR, Barnes CL, Gates KS. Application of Suzuki-Miyaura and Buchwald-Hartwig Cross-coupling Reactions to the Preparation of Substituted 1,2,4-Benzotriazine 1-Oxides Related to the Antitumor Agent Tirapazamine. J Heterocycl Chem 2017; 54:155-160. [PMID: 28439141 DOI: 10.1002/jhet.2559] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Many 1,2,4-benzotriazine 1,4-dioxides display the ability to selectively kill the oxygen-poor cells found in solid tumors. As a result, there is a desire for synthetic routes that afford access to substituted 1,2,4-benzotriazine 1-oxides that can be used as direct precursors in the synthesis of 1,2,4-benzotriazine 1,4-dioxides. Here we describe the use of Suzuki-Miyaura and Buchwald-Hartwig cross-coupling reactions for the construction of various 1,2,4-benzotriazine 1-oxide analogs bearing substituents at the 3-, 6-, and 7-positions.
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Affiliation(s)
- Ujjal Sarkar
- University of Missouri, Department of Chemistry, 125 Chemistry Building, Columbia, MO 65211
| | - Roman Hillebrand
- University of Missouri, Department of Chemistry, 125 Chemistry Building, Columbia, MO 65211
| | - Kevin M Johnson
- University of Missouri, Department of Chemistry, 125 Chemistry Building, Columbia, MO 65211
| | - Andrea H Cummings
- University of Missouri, Department of Chemistry, 125 Chemistry Building, Columbia, MO 65211
| | - Ngoc Linh Phung
- University of Missouri, Department of Chemistry, 125 Chemistry Building, Columbia, MO 65211
| | - Anuruddha Rajapakse
- University of Missouri, Department of Chemistry, 125 Chemistry Building, Columbia, MO 65211
| | - Haiying Zhou
- University of Missouri, Department of Chemistry, 125 Chemistry Building, Columbia, MO 65211
| | - Jordan R Willis
- University of Missouri, Department of Chemistry, 125 Chemistry Building, Columbia, MO 65211
| | - Charles L Barnes
- University of Missouri, Department of Chemistry, 125 Chemistry Building, Columbia, MO 65211
| | - Kent S Gates
- University of Missouri, Department of Chemistry, 125 Chemistry Building, Columbia, MO 65211.,University of Missouri, Department of Biochemistry, 125 Chemistry Building, Columbia, MO 65211
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16
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Patel A, Sant S. Hypoxic tumor microenvironment: Opportunities to develop targeted therapies. Biotechnol Adv 2016; 34:803-812. [PMID: 27143654 PMCID: PMC4947437 DOI: 10.1016/j.biotechadv.2016.04.005] [Citation(s) in RCA: 135] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2016] [Revised: 04/13/2016] [Accepted: 04/28/2016] [Indexed: 01/18/2023]
Abstract
In recent years, there has been great progress in the understanding of tumor biology and its surrounding microenvironment. Solid tumors create regions with low oxygen levels, generally termed as hypoxic regions. These hypoxic areas offer a tremendous opportunity to develop targeted therapies. Hypoxia is not a random by-product of the cellular milieu due to uncontrolled tumor growth; rather it is a constantly evolving participant in overall tumor growth and fate. This article reviews current trends and recent advances in drug therapies and delivery systems targeting hypoxia in the tumor microenvironment. In the first part, we give an account of important physicochemical changes and signaling pathways activated in the hypoxic microenvironment. This is then followed by various treatment strategies including hypoxia-sensitive signaling pathways and approaches to develop hypoxia-targeted drug delivery systems.
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Affiliation(s)
- Akhil Patel
- Department of Pharmaceutical Sciences, University of Pittsburgh School of Pharmacy, United States
| | - Shilpa Sant
- Department of Pharmaceutical Sciences, University of Pittsburgh School of Pharmacy, United States; Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15261, United States; McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA 15261, United States.
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17
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Cheng G, Sa W, Cao C, Guo L, Hao H, Liu Z, Wang X, Yuan Z. Quinoxaline 1,4-di-N-Oxides: Biological Activities and Mechanisms of Actions. Front Pharmacol 2016; 7:64. [PMID: 27047380 PMCID: PMC4800186 DOI: 10.3389/fphar.2016.00064] [Citation(s) in RCA: 64] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2016] [Accepted: 03/07/2016] [Indexed: 11/29/2022] Open
Abstract
Quinoxaline 1,4-di-N-oxides (QdNOs) have manifold biological properties, including antimicrobial, antitumoral, antitrypanosomal and antiinflammatory/antioxidant activities. These diverse activities endow them broad applications and prospects in human and veterinary medicines. As QdNOs arouse widespread interest, the evaluation of their medicinal chemistry is still in progress. In the meantime, adverse effects have been reported in some of the QdNO derivatives. For example, genotoxicity and bacterial resistance have been found in QdNO antibacterial growth promoters, conferring urgent need for discovery of new QdNO drugs. However, the modes of actions of QdNOs are not fully understood, hindering the development and innovation of these promising compounds. Here, QdNOs are categorized based on the activities and usages, among which the antimicrobial activities are consist of antibacterial, antimycobacterial and anticandida activities, and the antiprotozoal activities include antitrypanosomal, antimalarial, antitrichomonas, and antiamoebic activities. The structure-activity relationship and the mode of actions of each type of activity of QdNOs are summarized, and the toxicity and the underlying mechanisms are also discussed, providing insight for the future research and development of these fascinating compounds.
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Affiliation(s)
- Guyue Cheng
- MOA Laboratory for Risk Assessment of Quality and Safety of Livestock and Poultry Products, Huazhong Agricultural UniversityWuhan, China; College of Veterinary Medicine, Huazhong Agricultural UniversityWuhan, China
| | - Wei Sa
- College of Veterinary Medicine, Huazhong Agricultural University Wuhan, China
| | - Chen Cao
- College of Veterinary Medicine, Huazhong Agricultural University Wuhan, China
| | - Liangliang Guo
- College of Veterinary Medicine, Huazhong Agricultural University Wuhan, China
| | - Haihong Hao
- MOA Laboratory for Risk Assessment of Quality and Safety of Livestock and Poultry Products, Huazhong Agricultural UniversityWuhan, China; College of Veterinary Medicine, Huazhong Agricultural UniversityWuhan, China
| | - Zhenli Liu
- College of Veterinary Medicine, Huazhong Agricultural UniversityWuhan, China; National Reference Laboratory of Veterinary Drug Residues and MOA Key Laboratory for the Detection of Veterinary Drug Residues in Foods, Huazhong Agricultural UniversityWuhan, China
| | - Xu Wang
- MOA Laboratory for Risk Assessment of Quality and Safety of Livestock and Poultry Products, Huazhong Agricultural UniversityWuhan, China; College of Veterinary Medicine, Huazhong Agricultural UniversityWuhan, China
| | - Zonghui Yuan
- MOA Laboratory for Risk Assessment of Quality and Safety of Livestock and Poultry Products, Huazhong Agricultural UniversityWuhan, China; College of Veterinary Medicine, Huazhong Agricultural UniversityWuhan, China; National Reference Laboratory of Veterinary Drug Residues and MOA Key Laboratory for the Detection of Veterinary Drug Residues in Foods, Huazhong Agricultural UniversityWuhan, China
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18
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Abstract
The presence of a microenvironment within most tumours containing regions of low oxygen tension or hypoxia has profound biological and therapeutic implications. Tumour hypoxia is known to promote the development of an aggressive phenotype, resistance to both chemotherapy and radiotherapy and is strongly associated with poor clinical outcome. Paradoxically, it is recognised as a high-priority target and one of the therapeutic strategies designed to eradicate hypoxic cells in tumours is a group of compounds known collectively as hypoxia-activated prodrugs (HAPs) or bioreductive drugs. These drugs are inactive prodrugs that require enzymatic activation (typically by 1 or 2 electron oxidoreductases) to generate cytotoxic species with selectivity for hypoxic cells being determined by (1) the ability of oxygen to either reverse or inhibit the activation process and (2) the presence of elevated expression of oxidoreductases in tumours. The concepts underpinning HAP development were established over 40 years ago and have been refined over the years to produce a new generation of HAPs that are under preclinical and clinical development. The purpose of this article is to describe current progress in the development of HAPs focusing on the mechanisms of action, preclinical properties and clinical progress of leading examples.
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19
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Phillips RM. Targeting the hypoxic fraction of tumours using hypoxia-activated prodrugs. Cancer Chemother Pharmacol 2016; 77:441-57. [PMID: 26811177 PMCID: PMC4767869 DOI: 10.1007/s00280-015-2920-7] [Citation(s) in RCA: 159] [Impact Index Per Article: 19.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2015] [Accepted: 11/13/2015] [Indexed: 12/17/2022]
Abstract
The presence of a microenvironment within most tumours containing regions of low oxygen tension or hypoxia has profound biological and therapeutic implications. Tumour hypoxia is known to promote the development of an aggressive phenotype, resistance to both chemotherapy and radiotherapy and is strongly associated with poor clinical outcome. Paradoxically, it is recognised as a high-priority target and one of the therapeutic strategies designed to eradicate hypoxic cells in tumours is a group of compounds known collectively as hypoxia-activated prodrugs (HAPs) or bioreductive drugs. These drugs are inactive prodrugs that require enzymatic activation (typically by 1 or 2 electron oxidoreductases) to generate cytotoxic species with selectivity for hypoxic cells being determined by (1) the ability of oxygen to either reverse or inhibit the activation process and (2) the presence of elevated expression of oxidoreductases in tumours. The concepts underpinning HAP development were established over 40 years ago and have been refined over the years to produce a new generation of HAPs that are under preclinical and clinical development. The purpose of this article is to describe current progress in the development of HAPs focusing on the mechanisms of action, preclinical properties and clinical progress of leading examples.
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Affiliation(s)
- Roger M Phillips
- Department of Pharmacy, University of Huddersfield, Queensgate, Huddersfield, HD1 3DH, UK.
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20
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Cheng G, Li B, Wang C, Zhang H, Liang G, Weng Z, Hao H, Wang X, Liu Z, Dai M, Wang Y, Yuan Z. Systematic and Molecular Basis of the Antibacterial Action of Quinoxaline 1,4-Di-N-Oxides against Escherichia coli. PLoS One 2015; 10:e0136450. [PMID: 26296207 PMCID: PMC4546592 DOI: 10.1371/journal.pone.0136450] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2015] [Accepted: 08/03/2015] [Indexed: 01/28/2023] Open
Abstract
Quinoxaline 1,4-di-N-oxides (QdNOs) are widely known as potent antibacterial agents, but their antibacterial mechanisms are incompletely understood. In this study, the transcriptomic and proteomic profiles of Escherichia coli exposed to QdNOs were integratively investigated, and the results demonstrated that QdNOs mainly induced an SOS response and oxidative stress. Moreover, genes and proteins involved in the bacterial metabolism, cellular structure maintenance, resistance and virulence were also found to be changed, conferring bacterial survival strategies. Biochemical assays showed that reactive oxygen species were induced in the QdNO-treated bacteria and that free radical scavengers attenuated the antibacterial action of QdNOs and DNA damage, suggesting an oxidative-DNA-damage action of QdNOs. The QdNO radical intermediates, likely carbon-centered and aryl-type radicals, as identified by electron paramagnetic resonance, were the major radicals induced by QdNOs, and xanthine oxidase was one of the QdNO-activating enzymes. This study provides new insights into the action of QdNOs in a systematic manner and increases the current knowledge of bacterial physiology under antibiotic stresses, which may be of great value in the development of new antibiotic-potentiating strategies.
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Affiliation(s)
- Guyue Cheng
- MOA Laboratory for Risk Assessment of Quality and Safety of Livestock and Poultry Products, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
- Hubei Collaborative Innovation Center for Animal Nutrition and Feed Safety, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
| | - Bei Li
- MOA Laboratory for Risk Assessment of Quality and Safety of Livestock and Poultry Products, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
| | - Chenxi Wang
- MOA Laboratory for Risk Assessment of Quality and Safety of Livestock and Poultry Products, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
| | - Hongfei Zhang
- MOA Laboratory for Risk Assessment of Quality and Safety of Livestock and Poultry Products, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
| | - Guixia Liang
- MOA Laboratory for Risk Assessment of Quality and Safety of Livestock and Poultry Products, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
| | - Zhifei Weng
- MOA Laboratory for Risk Assessment of Quality and Safety of Livestock and Poultry Products, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
| | - Haihong Hao
- MOA Laboratory for Risk Assessment of Quality and Safety of Livestock and Poultry Products, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
- Hubei Collaborative Innovation Center for Animal Nutrition and Feed Safety, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
| | - Xu Wang
- MOA Laboratory for Risk Assessment of Quality and Safety of Livestock and Poultry Products, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
- Hubei Collaborative Innovation Center for Animal Nutrition and Feed Safety, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
| | - Zhenli Liu
- National Reference Laboratory of Veterinary Drug Residues (HZAU) and MAO Key Laboratory for Detection of Veterinary Drug Residues, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
- Hubei Collaborative Innovation Center for Animal Nutrition and Feed Safety, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
| | - Menghong Dai
- MOA Laboratory for Risk Assessment of Quality and Safety of Livestock and Poultry Products, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
- Hubei Collaborative Innovation Center for Animal Nutrition and Feed Safety, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
- * E-mail: (MD); (YW); (ZY)
| | - Yulian Wang
- National Reference Laboratory of Veterinary Drug Residues (HZAU) and MAO Key Laboratory for Detection of Veterinary Drug Residues, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
- Hubei Collaborative Innovation Center for Animal Nutrition and Feed Safety, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
- * E-mail: (MD); (YW); (ZY)
| | - Zonghui Yuan
- MOA Laboratory for Risk Assessment of Quality and Safety of Livestock and Poultry Products, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
- National Reference Laboratory of Veterinary Drug Residues (HZAU) and MAO Key Laboratory for Detection of Veterinary Drug Residues, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
- Hubei Collaborative Innovation Center for Animal Nutrition and Feed Safety, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
- * E-mail: (MD); (YW); (ZY)
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21
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Abstract
A newly-developed metal-carbene radical polymerization mechanism is proposed for poly(imidazole-Pd)-mediated carbene polymerization, which could produce stereoregular polycarbenes besides atactic polycarbenes.
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Affiliation(s)
- Feifei Li
- Department of Polymer Science
- College of Chemistry and Molecular Sciences
- Wuhan University
- Wuhan 430072
- China
| | - Longqiang Xiao
- Department of Polymer Science
- College of Chemistry and Molecular Sciences
- Wuhan University
- Wuhan 430072
- China
| | - Lijian Liu
- Department of Polymer Science
- College of Chemistry and Molecular Sciences
- Wuhan University
- Wuhan 430072
- China
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22
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Li F, Xiao L, Li Y, Chen C, Liu L. The interception of a copper-based carbene radical with an α-carbonyl diazomethane radical: C1/C1N2 copolymerization. Chem Commun (Camb) 2015; 51:11964-7. [DOI: 10.1039/c5cc03716f] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The interception of a copper-based carbene radical with an α-carbonyl diazomethane radical affords the C1/C1N2 copolymer, which could be used as an upconversion agent.
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Affiliation(s)
- Feifei Li
- Department of Polymer Science
- College of Chemistry and Molecular Sciences
- Wuhan University
- Wuhan 430072
- China
| | - Longqiang Xiao
- Department of Polymer Science
- College of Chemistry and Molecular Sciences
- Wuhan University
- Wuhan 430072
- China
| | - Yan Li
- Department of Polymer Science
- College of Chemistry and Molecular Sciences
- Wuhan University
- Wuhan 430072
- China
| | - Cheng Chen
- Department of Polymer Science
- College of Chemistry and Molecular Sciences
- Wuhan University
- Wuhan 430072
- China
| | - Lijian Liu
- Department of Polymer Science
- College of Chemistry and Molecular Sciences
- Wuhan University
- Wuhan 430072
- China
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23
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Johnson K, Parsons ZD, Barnes CL, Gates KS. Toward hypoxia-selective DNA-alkylating agents built by grafting nitrogen mustards onto the bioreductively activated, hypoxia-selective DNA-oxidizing agent 3-amino-1,2,4-benzotriazine 1,4-dioxide (tirapazamine). J Org Chem 2014; 79:7520-31. [PMID: 25029663 PMCID: PMC4136725 DOI: 10.1021/jo501252p] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2014] [Indexed: 12/14/2022]
Abstract
Tirapazamine (3-amino-1,2,4-benzotriazine 1,4-dioxide) is a heterocyclic di-N-oxide that undergoes enzymatic deoxygenation selectively in the oxygen-poor (hypoxic) cells found in solid tumors to generate a mono-N-oxide metabolite. This work explored the idea that the electronic changes resulting from the metabolic deoxygenation of tirapazamine analogues might be exploited to activate a DNA-alkylating species selectively in hypoxic tissue. Toward this end, tirapazamine analogues bearing nitrogen mustard units were prepared. In the case of the tirapazamine analogue 18a bearing a nitrogen mustard unit at the 6-position, it was found that removal of the 4-oxide from the parent di-N-oxide to generate the mono-N-oxide analogue 17a did indeed cause a substantial increase in reactivity of the mustard unit, as measured by hydrolysis rates and DNA-alkylation yields. Hammett sigma values were measured to quantitatively assess the magnitude of the electronic changes induced by metabolic deoxygenation of the 3-amino-1,2,4-benzotriazine 1,4-dioxide heterocycle. The results provide evidence that the 1,2,4-benzotiazine 1,4-dioxide unit can serve as an oxygen-sensing prodrug platform for the selective unmasking of bioactive agents in hypoxic cells.
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Affiliation(s)
- Kevin
M. Johnson
- Departments of Chemistry and Biochemistry, University of Missouri, 125 Chemistry Building, Columbia, Missouri 65211, United
States
| | - Zachary D. Parsons
- Departments of Chemistry and Biochemistry, University of Missouri, 125 Chemistry Building, Columbia, Missouri 65211, United
States
| | - Charles L. Barnes
- Departments of Chemistry and Biochemistry, University of Missouri, 125 Chemistry Building, Columbia, Missouri 65211, United
States
| | - Kent S. Gates
- Departments of Chemistry and Biochemistry, University of Missouri, 125 Chemistry Building, Columbia, Missouri 65211, United
States
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24
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Lin SC, Liao WL, Lee JC, Tsai SJ. Hypoxia-regulated gene network in drug resistance and cancer progression. Exp Biol Med (Maywood) 2014; 239:779-792. [PMID: 24812122 DOI: 10.1177/1535370214532755] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Hypoxia is a common phenomenon of solid tumors and contributes to aggressive phenotype and treatment failure. Hypoxia-inducible factor (HIF), a versatile transcription factor that regulates more than 5% of total human genes, not only plays important roles in controlling physiological processes, but is also a crucial mediator in hypoxia-induced tumor progression and chemoresistance. Overexpression of HIF-1α is detected in a wide spectrum of cancers via different kinds of mechanisms, including reduced oxygen concentration, loss-of-function of tumor suppressor gene, activating mutation of oncogenes, and hyperactivation of protein kinase signaling pathways. HIF-regulated genes involve in many pathological processes such as metabolic switch, drug efflux, angiogenesis, cell proliferation, and anti-apoptosis, which ultimately leads to increased tumor growth and drug resistance. Due to the common failure of classic chemotherapeutic agents in treating hypoxic cancers, novel strategies have been developed to target tumors under hypoxic conditions including inhibition of HIF activity and administration of bioreductive drugs. These new strategies may provide more effective and specific methods in targeting hypoxic tumors.
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Affiliation(s)
- Shao-Chieh Lin
- Department of Surgery, College of Medicine, National Cheng Kung University, 1 University Road, Tainan 70101, Taiwan
| | - Wan-Lin Liao
- Department of Physiology, College of Medicine, National Cheng Kung University, 1 University Road, Tainan 70101, Taiwan
| | - Jenq-Chang Lee
- Department of Surgery, College of Medicine, National Cheng Kung University, 1 University Road, Tainan 70101, Taiwan
| | - Shaw-Jenq Tsai
- Department of Physiology, College of Medicine, National Cheng Kung University, 1 University Road, Tainan 70101, Taiwan
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25
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Anderson RF, Yadav P, Patel D, Reynisson J, Tipparaju SR, Guise CP, Patterson AV, Denny WA, Maroz A, Shinde SS, Hay MP. Characterisation of radicals formed by the triazine 1,4-dioxide hypoxia-activated prodrug, SN30000. Org Biomol Chem 2014; 12:3386-92. [PMID: 24737463 DOI: 10.1039/c4ob00236a] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The radical species underlying the activity of the bioreductive anticancer prodrug, SN30000, have been identified by electron paramagnetic resonance and pulse radiolysis techniques. Spin-trapping experiments indicate both an aryl-type radical and an oxidising radical, trapped as a carbon-centred radical, are formed from the protonated radical anion of SN30000. The carbon-centred radical, produced upon the one-electron oxidation of the 2-electron reduced metabolite of SN30000, oxidises 2-deoxyribose, a model for the site of damage on DNA which leads to double strand breaks. Calculations using density functional theory support the assignments made.
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Affiliation(s)
- Robert F Anderson
- Auckland Cancer Society Research Centre, Faculty of Medical and Health Sciences, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand.
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26
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Yadav P, Marshall AJ, Reynisson J, Denny WA, Hay MP, Anderson RF. Fragmentation of the quinoxaline N-oxide bond to the ˙OH radical upon one-electron bioreduction. Chem Commun (Camb) 2014; 50:13729-31. [DOI: 10.1039/c4cc05657d] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
One-electron reduction of 3-trifluoromethyl-quinoxaline 1,4-dioxide breaks the N-oxide bond to release the ˙OH radical.
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Affiliation(s)
- Pooja Yadav
- Auckland Cancer Society Research Centre
- University of Auckland
- Auckland 1142, New Zealand
| | - Andrew J. Marshall
- Auckland Cancer Society Research Centre
- University of Auckland
- Auckland 1142, New Zealand
| | - Jóhannes Reynisson
- School of Chemical Sciences
- University of Auckland
- Auckland 1142, New Zealand
| | - William A. Denny
- Auckland Cancer Society Research Centre
- University of Auckland
- Auckland 1142, New Zealand
| | - Michael P. Hay
- Auckland Cancer Society Research Centre
- University of Auckland
- Auckland 1142, New Zealand
| | - Robert F. Anderson
- Auckland Cancer Society Research Centre
- University of Auckland
- Auckland 1142, New Zealand
- School of Chemical Sciences
- University of Auckland
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Hypoxia-Directed Drug Strategies to Target the Tumor Microenvironment. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2014; 772:111-45. [DOI: 10.1007/978-1-4614-5915-6_6] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
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Shen X, Rajapakse A, Gallazzi F, Junnotula V, Fuchs-Knotts T, Glaser R, Gates KS. Isotopic labeling experiments that elucidate the mechanism of DNA strand cleavage by the hypoxia-selective antitumor agent 1,2,4-benzotriazine 1,4-di-N-oxide. Chem Res Toxicol 2013; 27:111-8. [PMID: 24328261 DOI: 10.1021/tx400356y] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The 1,2,4-benzotriazine 1,4-dioxides are an important class of potential anticancer drugs that selectively kill the low-oxygen (hypoxic) cells found in solid tumors. These compounds undergo intracellular one-electron enzymatic reduction to yield an oxygen-sensitive drug radical intermediate that partitions forward, under hypoxic conditions, to generate a highly reactive secondary radical that causes cell killing DNA damage. Here, we characterized bioreductively activated, hypoxia-selective DNA-strand cleavage by 1,2,4-benzotriazine 1,4-dioxide. We found that one-electron enzymatic activation of 1,2,4-benzotriazine 1,4-dioxide under hypoxic conditions in the presence of the deuterium atom donor methanol-d4 produced nondeuterated mono-N-oxide metabolites. This and the results of other isotopic labeling studies provided evidence against the generation of atom-abstracting drug radical intermediates and are consistent with a DNA-damage mechanism involving the release of hydroxyl radical from enzymatically activated 1,2,4-benzotriazine 1,4-dioxides.
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Affiliation(s)
- Xiulong Shen
- Department of Chemistry, University of Missouri , 125 Chemistry Building, Columbia, Missouri 65211, United States
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29
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Pandey AV, Flück CE. NADPH P450 oxidoreductase: structure, function, and pathology of diseases. Pharmacol Ther 2013; 138:229-54. [PMID: 23353702 DOI: 10.1016/j.pharmthera.2013.01.010] [Citation(s) in RCA: 168] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2012] [Accepted: 12/26/2012] [Indexed: 01/18/2023]
Abstract
Cytochrome P450 oxidoreductase (POR) is an enzyme that is essential for multiple metabolic processes, chiefly among them are reactions catalyzed by cytochrome P450 proteins for metabolism of steroid hormones, drugs and xenobiotics. Mutations in POR cause a complex set of disorders that often resemble defects in steroid metabolizing enzymes 17α-hydroxylase, 21-hydroxylase and aromatase. Since our initial reports of POR mutations in 2004, more than 200 different mutations and polymorphisms in POR gene have been identified. Several missense variations in POR have been tested for their effect on activities of multiple steroid and drug metabolizing P450 proteins. Mutations in POR may have variable effects on different P450 partner proteins depending on the location of the mutation. The POR mutations that disrupt the binding of co-factors have negative impact on all partner proteins, while mutations causing subtle structural changes may lead to altered interaction with specific partner proteins and the overall effect may be different for each partner. This review summarizes the recent discoveries related to mutations and polymorphisms in POR and discusses these mutations in the context of historical developments in the discovery and characterization of POR as an electron transfer protein. The review is focused on the structural, enzymatic and clinical implications of the mutations linked to newly identified disorders in humans, now categorized as POR deficiency.
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Affiliation(s)
- Amit V Pandey
- Department of Pediatrics, Division of Pediatric Endocrinology and Diabetology, University Children's Hospital Bern, and Department of Clinical Research, University of Bern, 3004 Bern, Switzerland.
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30
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Mbiya W, Chipinda I, Siegel PD, Mhike M, Simoyi RH. Substituent effects on the reactivity of benzoquinone derivatives with thiols. Chem Res Toxicol 2012; 26:112-23. [PMID: 23237669 DOI: 10.1021/tx300417z] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Benzoquinone (BQ) is an extremely potent electrophilic contact allergen that haptenates endogenous proteins through Michael addition (MA). It is also hypothesized that BQ may haptenate proteins via free radical formation. The objective of this study was to assess the inductive effects (activating and deactivating) of substituents on BQ reactivity and the mechanistic pathway of covalent binding to a nucleophilic thiol. The BQ binding of Cys34 on human serum albumin was studied, and for reactivity studies, nitrobenzenethiol (NBT) was used as a surrogate for protein binding of the BQ and benzoquinone derivatives (BQD). Stopped flow techniques were used to determine pseudofirst order rate constants (k) of methyl-, t-butyl-, and chlorine-substituted BQD reactions with NBT, whereas electron pair resonance (EPR) studies were performed to investigate the presence of the free radical mediated binding mechanism of BQD. Characterization of adducts was performed using mass spectrometry and nuclear magnetic resonance spectroscopy (NMR). The rate constant values demonstrated the chlorine-substituted (activated) BQD to be more reactive toward NBT than the methyl and t-butyl-substituted (deactivated) BQD, and this correlated with the respective EPR intensities. The EPR signal, however, was quenched in the presence of NBT suggesting MA as the dominant reaction pathway. MS and NMR results confirmed adduct formation to be a result of MA onto the BQ ring with vinylic substitution also occurring for chlorine-substituted derivatives. The binding positions on BQ and NBT/BQ(D) stoichiometric ratios were affected by whether the inductive effects of the substituents on the ring were positive or negative. The reactivity of BQ and BQD is discussed in terms of the potential relationship to potential allergenic potency.
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Affiliation(s)
- Wilbes Mbiya
- Department of Chemistry, Portland State University , Portland, Oregon 97207-0751, United States
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31
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Yin J, Glaser R, Gates KS. On the reaction mechanism of tirapazamine reduction chemistry: unimolecular N-OH homolysis, stepwise dehydration, or triazene ring-opening. Chem Res Toxicol 2012; 25:634-45. [PMID: 22390168 DOI: 10.1021/tx200546u] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The initial steps of the activation of tirapazamine (TPZ, 1, 3-amino-1,2,4-benzotriazine 1,4-N,N-dioxide) under hypoxic conditions consist of the one-electron reduction of 1 to radical anion 2 and the protonation of 2 at O(N4) or O(N1) to form neutral radicals 3 and 4, respectively. There are some questions, however, as to whether radicals 3 and/or 4 will then undergo N-OH homolyses 3 → 5 + ·OH and 4 → 6 + ·OH or, alternatively, whether 3 and/or 4 may react by dehydration and form aminyl radicals via 3 → 11 + H(2)O and 4 → 12 + H(2)O or phenyl radicals via 3 → 17 + H(2)O. These outcomes might depend on the chemistry after the homolysis of 3 and/or 4, that is, dehydration may be the result of a two-step sequence that involves N-OH homolysis and formation of ·OH aggregates of 5 and 6 followed by H-abstraction within the ·OH aggregates to form hydrates of aminyls 11 and 12 or of phenyl 17. We studied these processes with configuration interaction theory, perturbation theory, and density functional theory. All stationary structures of OH aggregates of 5 and 6, of H(2)O aggregates of 11, 12, and 17, and of the transition state structures for H-abstraction were located and characterized by vibrational analysis and with methods of electron and spin-density analysis. The doublet radical 17 is a normal spin-polarized radical, whereas the doublet radicals 11 and 12 feature quartet instabilities. The computed reaction energies and activation barriers allow for dehydration in principle, but the productivity of all of these channels should be low for kinetic and dynamic reasons. With a view to plausible scenarios for the generation of latent aryl radical species without dehydration, we scanned the potential energy surfaces of 2-4 as a function of the (O)N1-Y (Y = C5a, N2) and (O)N4-Z (Z = C4a, C3) bond lengths. The elongation of any one of these bonds by 0.5 Å requires less than 25 kcal/mol, and this finding strongly suggests the possibility of bimolecular reactions of the spin-trap molecules with 2-4 concomitant with triazene ring-opening.
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Affiliation(s)
- Jian Yin
- Department of Chemistry, University of Missouri, Columbia, Missouri 65211, USA
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32
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Yin J, Glaser R, Gates KS. Electron and spin-density analysis of tirapazamine reduction chemistry. Chem Res Toxicol 2012; 25:620-33. [PMID: 22390194 DOI: 10.1021/tx2005458] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Tirapazamine (TPZ, 1, 3-amino-1,2,4-benzotriazine 1,4-N,N-dioxide), the radical anion 2 formed by one-electron reduction of 1, and neutral radicals 3 and 4 formed by protonation of 2 at O(N4) or O(N1), respectively, and their N-OH homolyses 3 → 5 + ·OH and 4 → 6 + ·OH have been studied with configuration interaction theory, perturbation theory, and density functional theory. A comprehensive comparative analysis is presented of structures and electronic structures and with focus on the development of an understanding of the spin-density distributions of the radical species. The skeletons of radicals 3 and 4 are distinctly nonplanar, several stereoisomeric structures are discussed, and there exists an intrinsic preference for 3 over 4. The N-oxides 1, 5, and 6 have closed-shell singlet ground states and low-lying, singlet biradical (SP-1, SP-6) or biradicaloid (SP-5) excited states. The doublet radicals 2, 3, and 4 are heavily spin-polarized. Most of the spin density of the doublet radicals 2, 3, and 4 is located in one (N,O)-region, and in particular, 3 and 4 are not C3-centered radicals. Significant amounts of spin density occur in both rings in the singlet biradical(oid) excited states of 1, 5, and 6. The dipole moment of the N2-C3(X) bond is large, and the nature of X provides a powerful handle to modulate the N2-C3 bond polarity with opposite effects on the two NO regions. Our studies show very low proton affinities of radical anion 2 and suggest that the pK(a) of radical [2+H] might be lower than 6. Implications are discussed regarding the formation of hydroxyl from 3 and/or 4, regarding the ability of 5 and 6 to react with carbon-centered radicals in a manner that ultimately leads to oxygen transfer, and regarding the interpretation of the EPR spectra of reduced TPZ species and of their spin-trap adducts.
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Affiliation(s)
- Jian Yin
- Department of Chemistry, University of Missouri, Columbia, Missouri 65211, USA
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33
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Hunter FW, Wang J, Patel R, Hsu HL, Hickey AJR, Hay MP, Wilson WR. Homologous recombination repair-dependent cytotoxicity of the benzotriazine di-N-oxide CEN-209: comparison with other hypoxia-activated prodrugs. Biochem Pharmacol 2011; 83:574-85. [PMID: 22182429 DOI: 10.1016/j.bcp.2011.12.005] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2011] [Revised: 11/29/2011] [Accepted: 12/01/2011] [Indexed: 11/30/2022]
Abstract
CEN-209 (SN30000) is a second-generation benzotriazine di-N-oxide currently in advanced preclinical development as a hypoxia-activated prodrug (HAP). Herein we describe the DNA repair-, hypoxia- and one-electron reductase-dependence of CEN-209 cytotoxicity. We deployed mutant CHO cell lines to generate DNA repair profiles for CEN-209, and compared the profiles with those for other HAPs. Hypoxic selectivity of CEN-209 was significantly greater than PR-104A and the nitro-chloromethylbenzindoline (nCBI/SN29428) and comparable to tirapazamine and TH-302. CEN-209 was selective for homologous recombination (HR) repair-deficient cells (Rad51d⁻/⁻), but less so than nitrogen mustard prodrugs TH-302 and PR-104A. Further, DNA repair profiles for CEN-209 differed under oxic and hypoxic conditions, with oxic cytotoxicity more dependent on HR. This feature was conserved across all three members of the benzotriazine di-N-oxide class examined (tirapazamine, CEN-209 and CEN-309/SN29751). Enhancing one-electron reduction of CEN-209 by forced expression of a soluble form of NADPH:cytochrome P450 oxidoreductase (sPOR) increased CEN-209 cytotoxicity more markedly under oxic than hypoxic conditions. Comparison of oxygen consumption, H₂O₂ production and metabolism of CEN-209 to the corresponding 1-oxide and nor-oxide reduced metabolites suggested that enhanced oxic cytotoxicity in cells with high one-electron reductase activity is due to futile redox cycling. This study supports the hypothesis that both oxic and hypoxic cell killing by CEN-209 is mechanistically analogous to tirapazamine and is dependent on oxidative DNA damage repaired via multiple pathways. However, HAPs that generate DNA interstrand cross-links, such as TH-302 and PR-104, may be more suitable than benzotriazine di-N-oxides for exploiting reported HR repair defects in hypoxic tumour cells.
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Affiliation(s)
- Francis W Hunter
- Auckland Cancer Society Research Centre, University of Auckland, Private Bag 92019, Auckland, New Zealand
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34
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Wang J, Foehrenbacher A, Su J, Patel R, Hay MP, Hicks KO, Wilson WR. The 2-Nitroimidazole EF5 Is a Biomarker for Oxidoreductases That Activate the Bioreductive Prodrug CEN-209 under Hypoxia. Clin Cancer Res 2011; 18:1684-95. [DOI: 10.1158/1078-0432.ccr-11-2296] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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35
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Chowdhury G, Sarkar U, Pullen S, Wilson WR, Rajapakse A, Fuchs-Knotts T, Gates KS. DNA strand cleavage by the phenazine di-N-oxide natural product myxin under both aerobic and anaerobic conditions. Chem Res Toxicol 2011; 25:197-206. [PMID: 22084973 DOI: 10.1021/tx2004213] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Heterocyclic N-oxides are an interesting class of antitumor agents that selectively kill the hypoxic cells found in solid tumors. The hypoxia-selective activity of the lead compound in this class, tirapazamine, stems from its ability to undergo intracellular one-electron reduction to an oxygen-sensitive drug radical intermediate. In the presence of molecular oxygen, the radical intermediate is back-oxidized to the parent molecule. Under hypoxic conditions, the extended lifetime of the drug radical intermediate enables its conversion to a highly cytotoxic DNA-damaging intermediate via a "deoxygenative" mechanism involving the loss of oxygen from one of its N-oxide groups. The natural product myxin is a phenazine di-N-oxide that displays potent antibiotic activity against a variety of organisms under aerobic conditions. In light of the current view of heterocyclic N-oxides as agents that selectively operate under hypoxic conditions, it is striking that myxin was identified from Sorangium extracts based upon its antibiotic properties under aerobic conditions. Therefore, we set out to examine the molecular mechanisms underlying the biological activity of myxin. We find that myxin causes bioreductively activated, radical-mediated DNA strand cleavage under both aerobic and anaerobic conditions. Our evidence indicates that strand cleavage occurs via a deoxygenative metabolism. We show that myxin displays potent cytotoxicity against the human colorectal cancer cell line HCT-116 under both aerobic and anaerobic conditions that is comparable to the cell-killing properties of tirapazamine under anaerobic conditions. This work sheds light on the processes by which the naturally occurring aromatic N-oxide myxin gains its potent antibiotic properties under aerobic conditions. Furthermore, these studies highlight the general potential for aromatic N-oxides to undergo highly cytotoxic deoxygenative metabolism following enzymatic one-electron reduction under aerobic conditions.
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Affiliation(s)
- Goutam Chowdhury
- Department of Chemistry, University of Missouri-Columbia, 125 Chemistry Building, Columbia, Missouri 65211, United States
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36
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Spasojević I. Free radicals and antioxidants at a glance using EPR spectroscopy. Crit Rev Clin Lab Sci 2011; 48:114-42. [DOI: 10.3109/10408363.2011.591772] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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Abstract
Hypoxia is a feature of most tumours, albeit with variable incidence and severity within a given patient population. It is a negative prognostic and predictive factor owing to its multiple contributions to chemoresistance, radioresistance, angiogenesis, vasculogenesis, invasiveness, metastasis, resistance to cell death, altered metabolism and genomic instability. Given its central role in tumour progression and resistance to therapy, tumour hypoxia might well be considered the best validated target that has yet to be exploited in oncology. However, despite an explosion of information on hypoxia, there are still major questions to be addressed if the long-standing goal of exploiting tumour hypoxia is to be realized. Here, we review the two main approaches, namely bioreductive prodrugs and inhibitors of molecular targets upon which hypoxic cell survival depends. We address the particular challenges and opportunities these overlapping strategies present, and discuss the central importance of emerging diagnostic tools for patient stratification in targeting hypoxia.
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Affiliation(s)
- William R Wilson
- Auckland Cancer Society Research Centre, The University of Auckland, Auckland, New Zealand.
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38
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Sarkar U, Glaser R, Parsons ZD, Barnes CL, Gates KS. Synthesis, Crystal Structure, and Rotational Energy Profile of 3-Cyclopropyl-1,2,4-benzotriazine 1,4-Di-N-oxide. JOURNAL OF CHEMICAL CRYSTALLOGRAPHY 2010; 40:624-629. [PMID: 22294856 PMCID: PMC3268128 DOI: 10.1007/s10870-010-9707-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
1,2,4-Benzotriazine 1,4-di-N-oxides are potent antitumor drug candidates that undergo in vivo bioreduction leading to selective DNA damage in the low oxygen (hypoxic) cells found in tumors. Tirapazamine (TPZ) is the lead compound in this family. Here we report on the synthesis, crystal structure, and conformational analysis of a new analog, 3-cyclopropyl-1,2,4-benzotriazine 1,4-di-N-oxide (3). Compound 3 (C(10)H(10)N(3)O(2)) crystallized in the monoclinic space group C2/c. Unit cell parameters for 3: a = 16.6306 (12), b = 7.799 (5), c = 16.0113 (11) Å, α = 90, β = 119.0440 (10), γ = 90, and z = 8.
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Affiliation(s)
- Ujjal Sarkar
- Department of Chemistry, University of Missouri-Columbia, Columbia, MO 65211
| | - Rainer Glaser
- Department of Chemistry, University of Missouri-Columbia, Columbia, MO 65211
| | - Zack D. Parsons
- Department of Chemistry, University of Missouri-Columbia, Columbia, MO 65211
| | - Charles L. Barnes
- Department of Chemistry, University of Missouri-Columbia, Columbia, MO 65211
| | - Kent S. Gates
- Department of Chemistry, University of Missouri-Columbia, Columbia, MO 65211
- Department of Biochemistry, University of Missouri-Columbia, Columbia, MO 65211
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Denny WA. Hypoxia-activated prodrugs in cancer therapy: progress to the clinic. Future Oncol 2010; 6:419-28. [PMID: 20222798 DOI: 10.2217/fon.10.1] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
The hypoxic cells common in solid tumors (because of their inefficient blood supply) limit the effectiveness of radiotherapy and many cytotoxic drugs. Nontoxic prodrugs that generate active species in hypoxic tissue by selective bioreduction have long been explored, and the first examples, representing a variety of different chemistries, have now reached advanced clinical trials. In the process, a great deal has been learnt about the properties that such drugs require to be successful, notably, efficient extravascular diffusion, appropriate reduction chemistry and kinetics, and an effective biological profile of the activated species, including a good bystander effect. The critical importance of prodrug diffusion and techniques to quantify this have assisted the development of models to predict the killing of tumor cells, which promises to help accelerate new drug evaluation. A cell cycle-independent mechanism of killing by the released cytotoxin is also a potential advantage, although it is likely that much of the killing will be when out-of-cycle hypoxic cells reoxygenate and resume division.
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Affiliation(s)
- William A Denny
- Auckland Cancer Society Research Centre, The University of Auckland, New Zealand.
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40
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Shinde SS, Maroz A, Hay MP, Patterson AV, Denny WA, Anderson RF. Characterization of radicals formed following enzymatic reduction of 3-substituted analogues of the hypoxia-selective cytotoxin 3-amino-1,2,4-benzotriazine 1,4-dioxide (tirapazamine). J Am Chem Soc 2010; 132:2591-9. [PMID: 20141134 DOI: 10.1021/ja908689f] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The mechanism by which the 1,2,4-benzotriazine 1,4-dioxide (BTO) class of bioreductive hypoxia-selective prodrugs (HSPs) form reactive radicals that kill cancer cells has been investigated by steady-state radiolysis, pulse radiolysis (PR), electron paramagnetic resonance (EPR), and density functional theory (DFT) calculations. Tirapazamine (TPZ, 3-amino BTO, 1) and a series of 3-substituted analogues, -H (2), -methyl (3), -ethyl (4), -methoxy (5), -ethoxymethoxy (6), and -phenyl (7), were reduced in aqueous solution under anaerobic steady-state radiolysis conditions, and their radicals were found to remove the substrates by short chain reactions of different lengths in the presence of formate ions. Multiple carbon-centered radical intermediates, produced upon anaerobic incubation of the compounds with cytochrome P(450) reductase enriched microsomes, were trapped by N-tert-butyl-alpha-phenylnitrone and observed using EPR. The highly oxidizing oxymethyl radical, from compound 5, was identified, and experimental spectra obtained for compounds 1, 2, 3, and 7 were well simulated after the inclusion of aryl radicals. The identification of a range of oxidizing radicals in the metabolism of the BTO compounds gives a new insight into the mechanism by which these HSPs can cause a wide variety of damage to biological targets such as DNA.
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Affiliation(s)
- Sujata S Shinde
- Department of Chemistry and Auckland Cancer Society Research Centre, The University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
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Junnotula V, Rajapakse A, Arbillaga L, de Cerain AL, Solano B, Villar R, Monge A, Gates KS. DNA strand cleaving properties and hypoxia-selective cytotoxicity of 7-chloro-2-thienylcarbonyl-3-trifluoromethylquinoxaline 1,4-dioxide. Bioorg Med Chem 2010; 18:3125-32. [PMID: 20371184 PMCID: PMC3268132 DOI: 10.1016/j.bmc.2010.03.042] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2010] [Revised: 03/15/2010] [Accepted: 03/16/2010] [Indexed: 11/28/2022]
Abstract
The heterocyclic N-oxide, 3-amino-1,2,4-benzotriazine 1,4-dioxide (tirapazamine, 1), shows promising antitumor activity in preclinical studies, but there is a continuing need to explore new compounds in this general structural category. In the work described here, we examined the properties of 7-chloro-2-thienylcarbonyl-3-trifluoromethylquinoxaline 1,4-dioxide (9h). We find that 9h causes redox-activated, hypoxia-selective DNA cleavage that mirrors the lead compound, tirapazamine, in both mechanism and potency. Furthermore, we find that 9h displays hypoxia-selective cytotoxicity against human cancer cell lines.
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42
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Villamena FA. Superoxide radical anion adduct of 5,5-dimethyl-1-pyrroline N-oxide. 6. Redox properties. J Phys Chem A 2010; 114:1153-60. [PMID: 19968309 DOI: 10.1021/jp909614u] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Cyclic nitrones have been employed for decades as spin trapping reagents for the detection and identification of transient radicals, and have been employed as pharmacological agent against ROS-mediated toxicity. The short half-life of the nitrone-superoxide adducts limits the application of nitrones in biological millieu, and therefore investigaton of the redox properties of the superoxide adducts is important. Moreover, computational investigation of the redox properties of the nitrones and their corresponding spin adducts may provide new insights into the nature of their pharmacological activity against ROS-induced toxicity. In general, electron-withdrawing group substitution at the C-5 position results in higher EAs and IPs making these substituted nitrones more susceptible to reduction but more difficult to oxidize compared to DMPO. One-electron reduction and oxidation of nitrones both resulted in elongated N-C(2) bonds indicating the tendency of radical anion and cation forms of nitrone to undergo ring-opening. The EAs and IPs of various O(2)(*-) adducts indicate that DEPMPO-O(2)H is the most difficult to reduce and oxidize compared to the O(2)(*-) adducts of DMPO, EMPO, and AMPO. In general, nitroxides gave higher EAs compared to nitrones making them more suceptible to reduction. One-electron oxidation of nitroxides leads to elongation of the N-C(2) bond but not for their reduction. The energetics of redox reaction of O(2)(*-) adducts was also explored. Results indicate that the reduction of O(2)(*-) adducts with O(2)(*-) is preferred followed by their oxidation by O(2) and then by O(2)(*-), but the maximum difference between these free energies of redox reactions in aqueous solution is only 0.21 kcal/mol. The preferred decomposition pathways for the one-electron oxidation and reduction of nitroxides was also explored, and formation of potentially biologically active products such as NO, H(2)O(2), and hydroxamic acid was predicted.
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Affiliation(s)
- Frederick A Villamena
- Department of Pharmacology and Center for Biomedical EPR Spectroscopy and Imaging, The Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio 43210, USA.
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Hypoxia-targeting by tirapazamine (TPZ) induces preferential growth inhibition of nasopharyngeal carcinoma cells with Chk1/2 activation. Invest New Drugs 2009; 29:401-10. [PMID: 20013349 DOI: 10.1007/s10637-009-9356-z] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2009] [Accepted: 11/09/2009] [Indexed: 01/29/2023]
Abstract
Hypoxia is commonly developed in solid tumors, which contributes to metastasis as well as radio- and chemo-resistance. Nasopharyngeal carcinoma (NPC) is a highly invasive and metastatic head and neck cancer prevalent in Southeast Asia with a high incidence rate of 15-30/100,000 persons/year (comparable to that of pancreatic cancer in the US). Previous clinical studies in NPC showed that hypoxia is detected in almost 100% of primary tumors and overexpression of hypoxia markers correlated with poor clinical outcome. Tirapazamine (TPZ) is a synthetic hypoxia-activated prodrug, which preferentially forms cytotoxic and DNA-damaging free radicals under hypoxia, thus selectively eradicate hypoxic cells. Here, we hypothesized that specific hypoxia-targeting by this clinical trial agent may be therapeutic for NPC. Our findings demonstrated that under hypoxia, TPZ was able to induce preferential growth inhibition of NPC cells, which was associated with marked cell cycle arrest at S-phase and PARP cleavage (a hallmark of apoptosis). Examination of S-phase checkpoint regulators revealed that Chk1 and Chk2 were selectively activated by TPZ in NPC cells under hypoxia. Hypoxia-selectivity of TPZ was also demonstrated by preferential downregulation of several important hypoxia-induced markers (HIF-1α, CA IX and VEGF) under hypoxia. Furthermore, we demonstrated that TPZ was equally effective and hypoxia-selective even in the presence of the EBV oncoprotein, LMP1 or the EBV genome. In summary, encouraging results from this proof-of-concept study implicate the therapeutic potential of hypoxia-targeting approaches for the treatment of NPC.
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