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Pal C. Small-molecule redox modulators with anticancer activity: A comprehensive mechanistic update. Free Radic Biol Med 2023; 209:211-227. [PMID: 37898387 DOI: 10.1016/j.freeradbiomed.2023.10.406] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Revised: 09/27/2023] [Accepted: 10/25/2023] [Indexed: 10/30/2023]
Abstract
The pursuit of effective anticancer therapies has led to a burgeoning interest in the realm of redox modulation. This review provides a comprehensive exploration of the intricate mechanisms by which diverse anticancer molecules leverage redox pathways for therapeutic intervention. Redox modulation, encompassing the fine balance of oxidation-reduction processes within cells, has emerged as a pivotal player in cancer treatment. This review delves into the multifaceted mechanisms of action employed by various anticancer compounds, including small molecules and natural products, to disrupt cancer cell proliferation and survival. Beginning with an examination of the role of redox signaling in cancer development and resistance, the review highlights how aberrant redox dynamics can fuel tumorigenesis. It then meticulously dissects the strategies employed by anticancer agents to induce oxidative stress, perturb redox equilibrium, and trigger apoptosis within cancer cells. Furthermore, the review explores the challenges and potential side effects associated with redox-based treatments, along with the development of novel redox-targeted agents. In summary, this review offers a profound understanding of the dynamic interplay between redox modulation and anticancer molecules, presenting promising avenues to revolutionize cancer therapy and enhance patient outcomes.
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Affiliation(s)
- Chinmay Pal
- Department of Chemistry, Gobardanga Hindu College, North 24 Parganas, West Bengal, 743273, India.
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2
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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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Bodzioch A, Pomikło D, Celeda M, Pietrzak A, Kaszyński P. 3-Substituted Benzo[e][1,2,4]triazines: Synthesis and Electronic Effects of the C(3) Substituent. J Org Chem 2019; 84:6377-6394. [DOI: 10.1021/acs.joc.9b00716] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Agnieszka Bodzioch
- Centre of Molecular and Macromolecular Studies, Polish Academy of Sciences, 90-363 Łódź, Poland
| | - Dominika Pomikło
- Centre of Molecular and Macromolecular Studies, Polish Academy of Sciences, 90-363 Łódź, Poland
| | | | - Anna Pietrzak
- Department of Chemistry, Middle Tennessee State University, Murfreesboro, Tennessee 37132, United States
- Faculty of Chemistry, Łódź University of Technology, 90-924 Łódź, Poland
| | - Piotr Kaszyński
- Centre of Molecular and Macromolecular Studies, Polish Academy of Sciences, 90-363 Łódź, Poland
- Faculty of Chemistry, University of Łódź, 91-403 Łódź, Poland
- Department of Chemistry, Middle Tennessee State University, Murfreesboro, Tennessee 37132, United States
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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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Elsaidi HR, Yang XH, Ahmadi F, Weinfeld M, Wiebe LI, Kumar P. Putative electron-affinic radiosensitizers and markers of hypoxic tissue: Synthesis and preliminary in vitro biological characterization of C3-amino-substituted benzotriazine dioxides (BTDOs). Eur J Med Chem 2019; 165:216-224. [PMID: 30684798 DOI: 10.1016/j.ejmech.2019.01.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2018] [Revised: 01/04/2019] [Accepted: 01/05/2019] [Indexed: 01/16/2023]
Abstract
INTRODUCTION The redox characteristics of 1,2,4-benzotriazine-1,4-dioxides (BTDOs) make them potential radiosensitizing agents for hypoxic cells in solid human cancers. Tirapazamine (TPZ) is the most clinically tested BTDO radiosensitizer, despite its toxicity at effective doses. To date, no BTDOs have been developed as diagnostic markers of tissue hypoxia. HYPOTHESIS TPZ analogues with appropriate reporting groups can act as potential radiosensitizers and hypoxia selective diagnostics. EXPERIMENTAL AND RESULTS 3-Chloro-1,2,4-benzotriazine 1-oxide was substituted at the C3 position to afford 3-(2-hydroxyethoxyethyl)-amino-1,2,4-benzotriazine-1-oxide, which was oxidized to 3-(2-hydroxyethoxyethyl)-amino-1,2,4-benzotriazine-1,4-dioxide (HO-EOE-TPZ) or converted to 3-(2-tosyloxyethoxyethyl)-amino-1,2,4-benzotriazine-1,4-dioxide (Tos-EOE-TPZ). Tos-EOE-TPZ was intended for use as a synthon for preparing 3-(2-azidoethoxyethyl)-amino-1,2,4-benzotriazine-1,4-dioxide (N3-EOE-TPZ) and 3-(2-iodoethoxyethyl)-amino-1,2,4-benzotriazine-1,4-dioxide (I-EOE-TPZ). The logP values (-0.69 to 0.61) for these molecules bracketed that of TPZ (-0.34). Cell line dependent cytotoxicities (IC50) in air were in the 10-100 μM range, with Hypoxia Cytotoxicity Ratios (HCR; IC50-air/IC50-hypoxia) of 5-10. LUMO calculations indicated that these molecules are in the optimal redox range for radiosensitization, offering cell-line-specific Relative Radiosensitization Ratios (RRSR; SER/OER) of 0.58-0.88, compared to TPZ (0.67-0.76). CONCLUSION The LUMO, IC50, HCR and RRSR values of 3-(2-substituted ethoxyethyl)-amino-1,2,4-benzotriazine-1,4-dioxides are similar to the corresponding values for TPZ, supporting the conclusion that these TPZ analogues are potentially useful as hypoxia-activated radiosensitizers. Further studies into their biodistributions in animal models are being pursued to determine the in vivo potential in hypoxia management.
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Affiliation(s)
- Hassan Rh Elsaidi
- Department of Oncology, Faculty of Medicine and Dentistry, University of Alberta, 11560 University Avenue Edmonton, Alberta, T6G 1Z2, Canada
| | - Xiao-Hong Yang
- Department of Oncology, Faculty of Medicine and Dentistry, University of Alberta, 11560 University Avenue Edmonton, Alberta, T6G 1Z2, Canada
| | - Fatemeh Ahmadi
- Department of Oncology, Faculty of Medicine and Dentistry, University of Alberta, 11560 University Avenue Edmonton, Alberta, T6G 1Z2, Canada
| | - Michael Weinfeld
- Department of Oncology, Faculty of Medicine and Dentistry, University of Alberta, 11560 University Avenue Edmonton, Alberta, T6G 1Z2, Canada
| | - Leonard I Wiebe
- Department of Oncology, Faculty of Medicine and Dentistry, University of Alberta, 11560 University Avenue Edmonton, Alberta, T6G 1Z2, Canada; Joint Appointment to Faculty of Pharmacy and Pharmaceutical Sciences, University of Alberta, Edmonton, Alberta T6G 2E1, Canada
| | - Piyush Kumar
- Department of Oncology, Faculty of Medicine and Dentistry, University of Alberta, 11560 University Avenue Edmonton, Alberta, T6G 1Z2, Canada.
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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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Cascioferro S, Parrino B, Spanò V, Carbone A, Montalbano A, Barraja P, Diana P, Cirrincione G. An overview on the recent developments of 1,2,4-triazine derivatives as anticancer compounds. Eur J Med Chem 2017; 142:328-375. [PMID: 28851503 DOI: 10.1016/j.ejmech.2017.08.009] [Citation(s) in RCA: 64] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2017] [Revised: 07/31/2017] [Accepted: 08/02/2017] [Indexed: 02/06/2023]
Abstract
The synthesis, the antitumor activity, the SAR and, whenever described, the possible mode of action of 1,2,4-triazine derivatives, their N-oxides, N,N'-dioxides as well as the benzo- and hetero-fused systems are reported. Herein are treated derivatives disclosed to literature from the beginning of this century up to 2016. Among the three possible triazine isomers, 1,2,4-triazines are the most studied ones and many derivatives having remarkable antitumor activity have been reported in the literature and also patented reaching advanced phases of clinical trials.
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Affiliation(s)
- Stella Cascioferro
- Dipartimento di Scienze e Tecnologie Biologiche Chimiche e Farmaceutiche (STEBICEF), Università degli Studi di Palermo, Via Archirafi 32, 90123 Palermo, Italy
| | - Barbara Parrino
- Dipartimento di Scienze e Tecnologie Biologiche Chimiche e Farmaceutiche (STEBICEF), Università degli Studi di Palermo, Via Archirafi 32, 90123 Palermo, Italy
| | - Virginia Spanò
- Dipartimento di Scienze e Tecnologie Biologiche Chimiche e Farmaceutiche (STEBICEF), Università degli Studi di Palermo, Via Archirafi 32, 90123 Palermo, Italy
| | - Anna Carbone
- Dipartimento di Scienze e Tecnologie Biologiche Chimiche e Farmaceutiche (STEBICEF), Università degli Studi di Palermo, Via Archirafi 32, 90123 Palermo, Italy
| | - Alessandra Montalbano
- Dipartimento di Scienze e Tecnologie Biologiche Chimiche e Farmaceutiche (STEBICEF), Università degli Studi di Palermo, Via Archirafi 32, 90123 Palermo, Italy
| | - Paola Barraja
- Dipartimento di Scienze e Tecnologie Biologiche Chimiche e Farmaceutiche (STEBICEF), Università degli Studi di Palermo, Via Archirafi 32, 90123 Palermo, Italy
| | - Patrizia Diana
- Dipartimento di Scienze e Tecnologie Biologiche Chimiche e Farmaceutiche (STEBICEF), Università degli Studi di Palermo, Via Archirafi 32, 90123 Palermo, Italy
| | - Girolamo Cirrincione
- Dipartimento di Scienze e Tecnologie Biologiche Chimiche e Farmaceutiche (STEBICEF), Università degli Studi di Palermo, Via Archirafi 32, 90123 Palermo, Italy.
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Mistry IN, Thomas M, Calder EDD, Conway SJ, Hammond EM. Clinical Advances of Hypoxia-Activated Prodrugs in Combination With Radiation Therapy. Int J Radiat Oncol Biol Phys 2017; 98:1183-1196. [PMID: 28721903 DOI: 10.1016/j.ijrobp.2017.03.024] [Citation(s) in RCA: 93] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2016] [Revised: 02/24/2017] [Accepted: 03/14/2017] [Indexed: 12/29/2022]
Abstract
With the increasing incidence of cancer worldwide, the need for specific, effective therapies is ever more urgent. One example of targeted cancer therapeutics is hypoxia-activated prodrugs (HAPs), also known as bioreductive prodrugs. These prodrugs are inactive in cells with normal oxygen levels but in hypoxic cells (with low oxygen levels) undergo chemical reduction to the active compound. Hypoxia is a common feature of solid tumors and is associated with a more aggressive phenotype and resistance to all modes of therapy. Therefore, the combination of radiation therapy and bioreductive drugs presents an attractive opportunity for synergistic effects, because the HAP targets the radiation-resistant hypoxic cells. Hypoxia-activated prodrugs have typically been precursors of DNA-damaging agents, but a new generation of molecularly targeted HAPs is emerging. By targeting proteins associated with tumorigenesis and survival, these compounds may result in greater selectivity over healthy tissue. We review the clinical progress of HAPs as adjuncts to radiation therapy and conclude that the use of HAPs alongside radiation is vastly underexplored at the clinical level.
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Affiliation(s)
- Ishna N Mistry
- Cancer Research UK/Medical Research Council Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford, United Kingdom
| | - Matthew Thomas
- Cancer Research UK/Medical Research Council Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford, United Kingdom
| | - Ewen D D Calder
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Oxford, United Kingdom
| | - Stuart J Conway
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Oxford, United Kingdom
| | - Ester M Hammond
- Cancer Research UK/Medical Research Council Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford, United Kingdom.
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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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Anderson RF, Yadav P, Shinde SS, Hong CR, Pullen SM, Reynisson J, Wilson WR, Hay MP. Radical Chemistry and Cytotoxicity of Bioreductive 3-Substituted Quinoxaline Di-N-Oxides. Chem Res Toxicol 2016; 29:1310-24. [PMID: 27380897 DOI: 10.1021/acs.chemrestox.6b00133] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The radical chemistry and cytotoxicity of a series of quinoxaline di-N-oxide (QDO) compounds has been investigated to explore the mechanism of action of this class of bioreductive drugs. A series of water-soluble 3-trifluoromethyl (4-10), 3-phenyl (11-19), and 3-methyl (20-21) substituted QDO compounds were designed to span a range of electron affinities consistent with bioreduction. The stoichiometry of loss of QDOs by steady-state radiolysis of anaerobic aqueous formate buffer indicated that one-electron reduction of QDOs generates radicals able to initiate chain reactions by oxidation of formate. The 3-trifluoromethyl analogues exhibited long chain reactions consistent with the release of the HO(•), as identified in EPR spin trapping experiments. Several carbon-centered radical intermediates, produced by anaerobic incubation of the QDO compounds with N-terminal truncated cytochrome P450 reductase (POR), were characterized using N-tert-butyl-α-phenylnitrone (PBN) and 5-(diethoxyphosphoryl)-5-methyl-1-pyrroline-N-oxide (DEPMPO) spin traps and were observed by EPR. Experimental data were well simulated for the production of strongly oxidizing radicals, capable of H atom abstraction from methyl groups. The kinetics of formation and decay of the radicals produced following one-electron reduction of the parent compounds, both in oxic and anoxic solutions, were determined using pulse radiolysis. Back oxidation of the initially formed radical anions by molecular oxygen did not compete effectively with the breakdown of the radical anions to form oxidizing radicals. The QDO compounds displayed low hypoxic selectivity when tested against oxic and hypoxic cancer cell lines in vitro. The results from this study form a kinetic description and explanation of the low hypoxia-selective cytotoxicity of QDOs against cancer cells compared to the related benzotriazine 1,4-dioxide (BTO) class of compounds.
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Affiliation(s)
- Robert F Anderson
- School of Chemical Sciences, ‡Auckland Cancer Society Research Centre, and §Maurice Wilkins Centre, University of Auckland , Private Bag 92019, Auckland 1142, New Zealand
| | - Pooja Yadav
- School of Chemical Sciences, ‡Auckland Cancer Society Research Centre, and §Maurice Wilkins Centre, University of Auckland , Private Bag 92019, Auckland 1142, New Zealand
| | - Sujata S Shinde
- School of Chemical Sciences, ‡Auckland Cancer Society Research Centre, and §Maurice Wilkins Centre, University of Auckland , Private Bag 92019, Auckland 1142, New Zealand
| | - Cho R Hong
- School of Chemical Sciences, ‡Auckland Cancer Society Research Centre, and §Maurice Wilkins Centre, University of Auckland , Private Bag 92019, Auckland 1142, New Zealand
| | - Susan M Pullen
- School of Chemical Sciences, ‡Auckland Cancer Society Research Centre, and §Maurice Wilkins Centre, University of Auckland , Private Bag 92019, Auckland 1142, New Zealand
| | - Jóhannes Reynisson
- School of Chemical Sciences, ‡Auckland Cancer Society Research Centre, and §Maurice Wilkins Centre, University of Auckland , Private Bag 92019, Auckland 1142, New Zealand
| | - William R Wilson
- School of Chemical Sciences, ‡Auckland Cancer Society Research Centre, and §Maurice Wilkins Centre, University of Auckland , Private Bag 92019, Auckland 1142, New Zealand
| | - Michael P Hay
- School of Chemical Sciences, ‡Auckland Cancer Society Research Centre, and §Maurice Wilkins Centre, University of Auckland , Private Bag 92019, Auckland 1142, New Zealand
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Phillips RM, Hendriks HR, Peters GJ. EO9 (Apaziquone): from the clinic to the laboratory and back again. Br J Pharmacol 2014; 168:11-8. [PMID: 22509926 DOI: 10.1111/j.1476-5381.2012.01996.x] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
EO9 (Apaziquone) is a bioreductive drug that has a chequered history. It underwent clinical trial but failed to show activity in phase II clinical trials when administered i.v. Poor drug delivery to tumours caused by a combination of rapid pharmacokinetic elimination and poor penetration through avascular tissue were the major factors responsible for EO9's poor efficacy. Based upon an understanding of why EO9 failed, a further clinical trial against patients with superficial transitional cell carcinoma of the bladder was conducted. The rationale for this was that intravesical administration directly into the bladder would circumvent the drug delivery problem, and any drug reaching the blood supply would be rapidly cleared thereby reducing the risk of systemic exposure. EO9 was well tolerated, and clinical activity against marker lesions was recorded in both phase I and II clinical trials. This article charts the pharmacological history of EO9 and discusses the potential implications that 'the EO9 story' has for the development of other loco-regional therapies.
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Affiliation(s)
- Roger M Phillips
- Institute of Cancer Therapeutics, University of Bradford, United Kingdom.
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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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13
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Foehrenbacher A, Secomb TW, Wilson WR, Hicks KO. Design of optimized hypoxia-activated prodrugs using pharmacokinetic/pharmacodynamic modeling. Front Oncol 2013; 3:314. [PMID: 24409417 PMCID: PMC3873531 DOI: 10.3389/fonc.2013.00314] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2013] [Accepted: 12/11/2013] [Indexed: 01/17/2023] Open
Abstract
Hypoxia contributes to resistance of tumors to some cytotoxic drugs and to radiotherapy, but can in principle be exploited with hypoxia-activated prodrugs (HAP). HAP in clinical development fall into two broad groups. Class I HAP (like the benzotriazine N-oxides tirapazamine and SN30000), are activated under relatively mild hypoxia. In contrast, Class II HAP (such as the nitro compounds PR-104A or TH-302) are maximally activated only under extreme hypoxia, but their active metabolites (effectors) diffuse to cells at intermediate O2 and thus also eliminate moderately hypoxic cells. Here, we use a spatially resolved pharmacokinetic/pharmacodynamic (SR-PK/PD) model to compare these two strategies and to identify the features required in an optimal Class II HAP. The model uses a Green's function approach to calculate spatial and longitudinal gradients of O2, prodrug, and effector concentrations, and resulting killing in a digitized 3D tumor microregion to estimate activity as monotherapy and in combination with radiotherapy. An analogous model for a normal tissue with mild hypoxia and short intervessel distances (based on a cremaster muscle microvessel network) was used to estimate tumor selectivity of cell killing. This showed that Class II HAP offer advantages over Class I including higher tumor selectivity and greater freedom to vary prodrug diffusibility and rate of metabolic activation. The model suggests that the largest gains in class II HAP antitumor activity could be realized by optimizing effector stability and prodrug activation rates. We also use the model to show that diffusion of effector into blood vessels is unlikely to materially increase systemic exposure for realistic tumor burdens and effector clearances. However, we show that the tumor selectivity achievable by hypoxia-dependent prodrug activation alone is limited if dose-limiting normal tissues are even mildly hypoxic.
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Affiliation(s)
- Annika Foehrenbacher
- Auckland Cancer Society Research Centre, The University of Auckland, Auckland, New Zealand
| | | | - William R. Wilson
- Auckland Cancer Society Research Centre, The University of Auckland, Auckland, New Zealand
| | - Kevin O. Hicks
- Auckland Cancer Society Research Centre, The University of Auckland, Auckland, New Zealand
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Evaluation of different PAMAM dendrimers as molecular vehicle of 1,2,4-triazine N-oxide derivative with potential antitumor activity. J INCL PHENOM MACRO 2013. [DOI: 10.1007/s10847-013-0324-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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15
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Transferring oxygen isotopes to 1,2,4-benzotriazine 1-oxides forming the corresponding 1,4-dioxides by using the HOF·CH3CN complex. Tetrahedron 2012. [DOI: 10.1016/j.tet.2012.08.017] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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16
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Zuckerman NB, Myers AS, Quan TK, Bray WM, Lokey RS, Hartzog GA, Konopelski JP. Structural determination of NSC 670224, synthesis of analogues and biological evaluation. ChemMedChem 2012; 7:761-5. [PMID: 22378491 DOI: 10.1002/cmdc.201200038] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2012] [Indexed: 11/10/2022]
Abstract
Follow my lead! NSC 670224, previously shown to be toxic to Saccharomyces cerevisiae at low micromolar concentrations, potentially acts via a mechanism of action related to that of tamoxifen (NSC 180973), breast cancer drug. The structure of NSC 670224, previously thought to be a 2,4-dichloro arene, was established as the 3,4-dichloro arene, and a focused library of analogues were synthesized and biologically evaluated.
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Affiliation(s)
- Nathaniel B Zuckerman
- Department of Chemistry and Biochemistry, University of California, Santa Cruz (UCSC), Santa Cruz, CA 95064, USA
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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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18
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Xia Q, Zhang L, Zhang J, Sheng R, Yang B, He Q, Hu Y. Synthesis, hypoxia-selective cytotoxicity of new 3-amino-1,2,4-benzotriazine-1,4-dioxide derivatives. Eur J Med Chem 2011; 46:919-26. [DOI: 10.1016/j.ejmech.2011.01.007] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2010] [Revised: 12/02/2010] [Accepted: 01/07/2011] [Indexed: 11/28/2022]
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19
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Hicks KO, Siim BG, Jaiswal JK, Pruijn FB, Fraser AM, Patel R, Hogg A, Liyanage HDS, Dorie MJ, Brown JM, Denny WA, Hay MP, Wilson WR. Pharmacokinetic/pharmacodynamic modeling identifies SN30000 and SN29751 as tirapazamine analogues with improved tissue penetration and hypoxic cell killing in tumors. Clin Cancer Res 2010; 16:4946-57. [PMID: 20732963 DOI: 10.1158/1078-0432.ccr-10-1439] [Citation(s) in RCA: 106] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
PURPOSE Tirapazamine (TPZ) has attractive features for targeting hypoxic cells in tumors but has limited clinical activity, in part because of poor extravascular penetration. Here, we identify improved TPZ analogues by using a spatially resolved pharmacokinetic/pharmacodynamic (SR-PKPD) model that considers tissue penetration explicitly during lead optimization. EXPERIMENTAL DESIGN The SR-PKPD model was used to guide the progression of 281 TPZ analogues through a hierarchical screen. For compounds exceeding hypoxic selectivity thresholds in single-cell cultures, SR-PKPD model parameters (kinetics of bioreductive metabolism, clonogenic cell killing potency, diffusion coefficients in multicellular layers, and plasma pharmacokinetics at well tolerated doses in mice) were measured to prioritize testing in xenograft models in combination with radiation. RESULTS SR-PKPD-guided lead optimization identified SN29751 and SN30000 as the most promising hypoxic cytotoxins from two different structural subseries. Both were reduced to the corresponding 1-oxide selectively under hypoxia by HT29 cells, with an oxygen dependence quantitatively similar to that of TPZ. SN30000, in particular, showed higher hypoxic potency and selectivity than TPZ in tumor cell cultures and faster diffusion through HT29 and SiHa multicellular layers. Both compounds also provided superior plasma PK in mice and rats at equivalent toxicity. In agreement with SR-PKPD predictions, both were more active than TPZ with single dose or fractionated radiation against multiple human tumor xenografts. CONCLUSIONS SN30000 and SN29751 are improved TPZ analogues with potential for targeting tumor hypoxia in humans. Novel SR-PKPD modeling approaches can be used for lead optimization during anticancer drug development.
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Affiliation(s)
- Kevin O Hicks
- Auckland Cancer Society Research Centre, The University of Auckland, Auckland, New Zealand
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20
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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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21
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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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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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23
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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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Abstract
Redox dysregulation originating from metabolic alterations and dependence on mitogenic and survival signaling through reactive oxygen species represents a specific vulnerability of malignant cells that can be selectively targeted by redox chemotherapeutics. This review will present an update on drug discovery, target identification, and mechanisms of action of experimental redox chemotherapeutics with a focus on pro- and antioxidant redox modulators now in advanced phases of preclinal and clinical development. Recent research indicates that numerous oncogenes and tumor suppressor genes exert their functions in part through redox mechanisms amenable to pharmacological intervention by redox chemotherapeutics. The pleiotropic action of many redox chemotherapeutics that involves simultaneous modulation of multiple redox sensitive targets can overcome cancer cell drug resistance originating from redundancy of oncogenic signaling and rapid mutation.Moreover, some redox chemotherapeutics may function according to the concept of synthetic lethality (i.e., drug cytotoxicity is confined to cancer cells that display loss of function mutations in tumor suppressor genes or upregulation of oncogene expression). The impressive number of ongoing clinical trials that examine therapeutic performance of novel redox drugs in cancer patients demonstrates that redox chemotherapy has made the crucial transition from bench to bedside.
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Affiliation(s)
- Georg T Wondrak
- Department of Pharmacology and Toxicology, College of Pharmacy, Arizona Cancer Center, University of Arizona, Tucson, Arizona, USA
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25
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Abstract
Anticancer prodrugs designed to target specifically tumor cells should increase therapeutic effectiveness and decrease systemic side effects in the treatment of cancer. Over the last 20 years, significant advances have been made in the development of anticancer prodrugs through the incorporation of triggers for reductive activation. Reductively activated prodrugs have been designed to target hypoxic tumor tissues, which are known to overexpress several endogenous reductive enzymes. In addition, exogenous reductive enzymes can be delivered to tumor cells through fusion with tumor-specific antibodies or overexpressed in tumor cells through gene delivery approaches. Many anticancer prodrugs have been designed to use both the endogenous and exogenous reductive enzymes for target-specific activation and these prodrugs often contain functional groups such as quinones, nitroaromatics, N-oxides, and metal complexes. Although no new agents have been approved for clinical use, several reductively activated prodrugs are in various stages of clinical trial. This review mainly focuses on the medicinal chemistry aspects of various classes of reductively activated prodrugs including design principles, structure-activity relationships, and mechanisms of activation and release of active drug molecules.
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Affiliation(s)
- Yu Chen
- Department of Pharmaceutical Chemistry, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, 160 Frelinghuysen Road, Piscataway, NJ 08854, USA
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Le QTX, Moon J, Redman M, Williamson SK, Lara PN, Goldberg Z, Gaspar LE, Crowley JJ, Moore DF, Gandara DR. Phase II study of tirapazamine, cisplatin, and etoposide and concurrent thoracic radiotherapy for limited-stage small-cell lung cancer: SWOG 0222. J Clin Oncol 2009; 27:3014-9. [PMID: 19364954 PMCID: PMC2702233 DOI: 10.1200/jco.2008.21.3868] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2008] [Accepted: 01/13/2009] [Indexed: 12/26/2022] Open
Abstract
PURPOSE A SWOG pilot study (S0004) showed that tirapazamine (TPZ) when combined with concurrent chemoradiotherapy yielded a promising median survival of 22 months in limited-stage small-cell lung cancer (LSCLC). We report results of the phase II study designed to confirm this result. PATIENTS AND METHODS The concurrent phase consisted of two cycles of cisplatin, etoposide, and once-daily radiation to 61 Gy. TPZ was given at 260 mg/m(2) on days 1, 29, and at 160 mg/m(2) on days 8, 10, 12, 36, 38, and 40. Consolidation consisted of two cycles of cisplatin and etoposide. Complete responders received prophylactic cranial irradiation. Results were considered promising if the median survival time was at least 21 months and of no further interest if < or = 14 months. RESULTS S0222 was closed early due to a report of excess toxicity for TPZ in a head and neck cancer trial elsewhere. Of planned 85 patients, 69 were accrued. In 68 assessable patients, 17 (25%) had grade 3 to 4 esophagitis and eight (12%) had grade 3 febrile neutropenia during the concurrent phase. There were three possible treatment-related deaths, two in concurrent phase (one progressive disease not otherwise specified within 30 days, one pericardial effusion) and one in consolidation phase (esophageal hemorrhage). At a median follow-up of 35 months, median progression-free survival was 11 months (95% CI, 10 to 13 months) and median overall survival was 21 months (95% CI, 17 to 33 months). CONCLUSION S0222 showed acceptable levels of toxicity and similar promising median survival as S0004. Further study of hypoxia-targeted therapy is warranted in LSCLC.
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Testa B. Prodrugs: bridging pharmacodynamic/pharmacokinetic gaps. Curr Opin Chem Biol 2009; 13:338-44. [PMID: 19473869 DOI: 10.1016/j.cbpa.2009.04.620] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2009] [Revised: 04/20/2009] [Accepted: 04/21/2009] [Indexed: 12/31/2022]
Abstract
In this mini review, prodrugs are discussed with a focus on their pharmaceutical, pharmacokinetic, and pharmacodynamic objectives, as well as on the resulting therapeutic benefits. Carrier-linked prodrugs remain the most extensively investigated and receive due attention here with recent successes highlighted. A clear trend is apparent in modern prodrug research, namely the increased attention given to the knowledge-based design of bioprecursors, namely prodrugs devoid of a detachable promoiety. In most cases, such prodrugs are activated by in situ reduction, hence their designation as bioreductive prodrugs. This is a particularly active field in the design of more selective, small-molecule antitumor agents. New antimicrobial agents are also in the pipeline. In addition, biooxidative bioprecursors offer a promising strategy in specific cases, as illustrated by the successful antiaggregating agent clopidogrel.
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Affiliation(s)
- Bernard Testa
- Pharmacy Department, University Hospital Centre, CHUV/BH-04, 46 Rue du Bugnon, CH-1011 Lausanne, Switzerland.
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28
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Junnotula V, Sarkar U, Sinha S, Gates KS. Initiation of DNA strand cleavage by 1,2,4-benzotriazine 1,4-dioxide antitumor agents: mechanistic insight from studies of 3-methyl-1,2,4-benzotriazine 1,4-dioxide. J Am Chem Soc 2009; 131:1015-24. [PMID: 19117394 PMCID: PMC2819123 DOI: 10.1021/ja8049645] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The antitumor agent 3-amino-1,2,4-benzotriazine 1,4-dioxide (tirapazamine, TPZ, 1) gains medicinal activity through its ability to selectively damage DNA in the hypoxic cells found inside solid tumors. This occurs via one-electron enzymatic reduction of TPZ to yield an oxygen-sensitive drug radical (2) that leads to oxidatively generated DNA damage under hypoxic conditions. Two possible mechanisms have been considered to account for oxidatively generated DNA damage by TPZ. First, homolysis of the N-OH bond in 2 may yield the well-known DNA-damaging agent, hydroxyl radical. Alternatively, it has been suggested that elimination of water from 2 generates a benzotriazinyl radical (4) as the ultimate DNA-damaging species. In the studies described here, the TPZ analogue 3-methyl-1,2,4-benzotriazine 1,4-dioxide (5) was employed as a tool to probe the mechanism of DNA damage within this new class of antitumor drugs. Initially, it was demonstrated that 5 causes redox-activated, hypoxia-selective oxidation of DNA and small organic substrates in a manner that is completely analogous to TPZ. This suggests that 5 and TPZ damage DNA by the same chemical mechanism. Importantly, the methyl substituent in 5 provides a means for assessing whether the putative benzotriazinyl intermediate 7 is generated following one-electron reduction. Two complementary isotopic labeling experiments provide evidence against the formation of the benzotriazinyl radical intermediate. Rather, a mechanism involving the release of hydroxyl radical from the activated drug radical intermediates can explain the DNA-cleaving properties of this class of antitumor drug candidates.
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Affiliation(s)
- Venkatraman Junnotula
- University of Missouri–Columbia, Departments of Chemistry and Biochemistry, 125 Chemistry Building, Columbia, MO 65211
| | - Ujjal Sarkar
- University of Missouri–Columbia, Departments of Chemistry and Biochemistry, 125 Chemistry Building, Columbia, MO 65211
| | - Sarmistha Sinha
- University of Missouri–Columbia, Departments of Chemistry and Biochemistry, 125 Chemistry Building, Columbia, MO 65211
| | - Kent S. Gates
- University of Missouri–Columbia, Departments of Chemistry and Biochemistry, 125 Chemistry Building, Columbia, MO 65211
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29
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Ciciani G, Coronnello M, Guerrini G, Selleri S, Cantore M, Failli P, Mini E, Costanzo A. Synthesis of new pyrazolo[5,1-c][1,2,4] benzotriazines, pyrazolo[5,1-c]pyrido[4,3-e][1,2,4] triazines and their open analogues as cytotoxic agents in normoxic and hypoxic conditions. Bioorg Med Chem 2008; 16:9409-19. [DOI: 10.1016/j.bmc.2008.09.055] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2008] [Revised: 09/16/2008] [Accepted: 09/23/2008] [Indexed: 11/30/2022]
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30
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Hay MP, Hicks KO, Pchalek K, Lee HH, Blaser A, Pruijn FB, Anderson RF, Shinde SS, Wilson WR, Denny WA. Tricyclic [1,2,4]triazine 1,4-dioxides as hypoxia selective cytotoxins. J Med Chem 2008; 51:6853-65. [PMID: 18847185 DOI: 10.1021/jm800967h] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
A series of novel tricyclic triazine-di- N-oxides (TTOs) related to tirapazamine have been designed and prepared. A wide range of structural arrangements with cycloalkyl, oxygen-, and nitrogen-containing saturated rings fused to the triazine core, coupled with various side chains linked to either hemisphere, resulted in TTO analogues that displayed hypoxia-selective cytotoxicity in vitro. Optimal rates of hypoxic metabolism and tissue diffusion coefficients were achieved with fused cycloalkyl rings in combination with both the 3-aminoalkyl or 3-alkyl substituents linked to weakly basic soluble amines. The selection was further refined using pharmacokinetic/pharmacodynamic model predictions of the in vivo hypoxic potency (AUC req) and selectivity (HCD) with 12 TTO analogues predicted to be active in vivo, subject to the achievement of adequate plasma pharmacokinetics.
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Affiliation(s)
- Michael P Hay
- Auckland Cancer Society Research Centre, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand.
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31
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Synthesis and biological activity of 1-methyl-tryptophan-tirapazamine hybrids as hypoxia-targeting indoleamine 2,3-dioxygenase inhibitors. Bioorg Med Chem 2008; 16:8661-9. [DOI: 10.1016/j.bmc.2008.07.087] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2008] [Revised: 07/29/2008] [Accepted: 07/30/2008] [Indexed: 11/19/2022]
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Pruijn FB, Patel K, Hay MP, Wilson WR, Hicks KO. Prediction of Tumour Tissue Diffusion Coefficients of Hypoxia-Activated Prodrugs from Physicochemical Parameters. Aust J Chem 2008. [DOI: 10.1071/ch08240] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The therapeutic activity of anticancer agents depends critically on their ability to penetrate through tumour tissue to reach their target cells, a requirement that is especially important for hypoxia-activated prodrugs. Here we use multicellular layers (MCL) grown in vitro from HT29 colon carcinoma cells to measure tissue diffusion coefficients (Dmcl) of 67 structurally diverse benzotriazine di-N-oxides (analogues of the hypoxia-activated prodrug tirapazamine) plus four miscellaneous compounds. An algorithm was developed to predict Dmcl from physicochemical parameters (molecular weight, octanol/water partition coefficient at pH 7.4, number of hydrogen bond donors and acceptors); the fitted multivariate relationship had an explained variance (R2) of 0.907 and predictive power (Q2) of 0.879. Using a subset of nine compounds tested as a single cassette, the algorithm was shown to apply, with some adjustment of coefficients, to MCLs from three other tumour cell lines with differing cell packing densities (SiHa, HCT8-Ea, and HCT8-Ra). The demonstrated relationships provide tools for optimizing extravascular transport of anticancer agents during lead optimization.
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