1
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Theys J, Patterson AV, Mowday AM. Clostridium Bacteria: Harnessing Tumour Necrosis for Targeted Gene Delivery. Mol Diagn Ther 2024; 28:141-151. [PMID: 38302842 PMCID: PMC10925577 DOI: 10.1007/s40291-024-00695-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/07/2024] [Indexed: 02/03/2024]
Abstract
Necrosis is a common feature of solid tumours that offers a unique opportunity for targeted cancer therapy as it is absent from normal healthy tissues. Tumour necrosis provides an ideal environment for germination of the anaerobic bacterium Clostridium from endospores, resulting in tumour-specific colonisation. Two main species, Clostridium novyi-NT and Clostridium sporogenes, are at the forefront of this therapy, showing promise in preclinical models. However, anti-tumour activity is modest when used as a single agent, encouraging development of Clostridium as a tumour-selective gene delivery system. Various methods, such as allele-coupled exchange and CRISPR-cas9 technology, can facilitate the genetic modification of Clostridium, allowing chromosomal integration of transgenes to ensure long-term stability of expression. Strains of Clostridium can be engineered to express prodrug-activating enzymes, resulting in the generation of active drug selectively in the tumour microenvironment (a concept termed Clostridium-directed enzyme prodrug therapy). More recently, Clostridium strains have been investigated in the context of cancer immunotherapy, either in combination with immune checkpoint inhibitors or with engineered strains expressing immunomodulatory molecules such as IL-2 and TNF-α. Localised expression of these molecules using tumour-targeting Clostridium strains has the potential to improve delivery and reduce systemic toxicity. In summary, Clostridium species represent a promising platform for cancer therapy, with potential for localised gene delivery and immunomodulation selectively within the tumour microenvironment. The ongoing clinical progress being made with C. novyi-NT, in addition to developments in genetic modification techniques and non-invasive imaging capabilities, are expected to further progress Clostridium as an option for cancer treatment.
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Affiliation(s)
- Jan Theys
- M-Lab, Department of Precision Medicine, GROW - School of Oncology and Reproduction, Maastricht University, 6229 ER, Maastricht, The Netherlands
| | - Adam V Patterson
- Auckland Cancer Society Research Centre, School of Medical Sciences, University of Auckland, Auckland, 1142, New Zealand
- Maurice Wilkins Centre for Molecular Biodiscovery, University of Auckland, Auckland, 1142, New Zealand
| | - Alexandra M Mowday
- Auckland Cancer Society Research Centre, School of Medical Sciences, University of Auckland, Auckland, 1142, New Zealand.
- Maurice Wilkins Centre for Molecular Biodiscovery, University of Auckland, Auckland, 1142, New Zealand.
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2
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Sharrock AV, Mumm JS, Bagdžiūnas G, Čėnas N, Arcus VL, Ackerley DF. The Crystal Structure of Engineered Nitroreductase NTR 2.0 and Impact of F70A and F108Y Substitutions on Substrate Specificity. Int J Mol Sci 2023; 24:ijms24076633. [PMID: 37047605 PMCID: PMC10095097 DOI: 10.3390/ijms24076633] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Revised: 03/25/2023] [Accepted: 03/30/2023] [Indexed: 04/05/2023] Open
Abstract
Bacterial nitroreductase enzymes that convert prodrugs to cytotoxins are valuable tools for creating transgenic targeted ablation models to study cellular function and cell-specific regeneration paradigms. We recently engineered a nitroreductase (“NTR 2.0”) for substantially enhanced reduction of the prodrug metronidazole, which permits faster cell ablation kinetics, cleaner interrogations of cell function, ablation of previously recalcitrant cell types, and extended ablation paradigms useful for modelling chronic diseases. To provide insight into the enhanced enzymatic mechanism of NTR 2.0, we have solved the X-ray crystal structure at 1.85 Angstroms resolution and compared it to the parental enzyme, NfsB from Vibrio vulnificus. We additionally present a survey of reductive activity with eight alternative nitroaromatic substrates, to provide access to alternative ablation prodrugs, and explore applications such as remediation of dinitrotoluene pollutants. The predicted binding modes of four key substrates were investigated using molecular modelling.
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Affiliation(s)
- Abigail V. Sharrock
- School of Biological Sciences, Victoria University of Wellington, Wellington 6012, New Zealand
| | - Jeff S. Mumm
- Wilmer Eye Institute, Johns Hopkins University, Baltimore, MD 21287, USA
| | - Gintautas Bagdžiūnas
- Institute of Biochemistry, University of Vilnius, Saulėtekio 7, LT-10257 Vilnius, Lithuania
| | - Narimantas Čėnas
- Institute of Biochemistry, University of Vilnius, Saulėtekio 7, LT-10257 Vilnius, Lithuania
| | - Vickery L. Arcus
- Te Aka Mātuatua-School of Science, University of Waikato, Hamilton 3240, New Zealand
| | - David F. Ackerley
- School of Biological Sciences, Victoria University of Wellington, Wellington 6012, New Zealand
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3
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Singleton DC, Mowday AM, Guise CP, Syddall SP, Bai SY, Li D, Ashoorzadeh A, Smaill JB, Wilson WR, Patterson AV. Bioreductive prodrug PR-104 improves the tumour distribution and titre of the nitroreductase-armed oncolytic adenovirus ONYX-411 NTR leading to therapeutic benefit. Cancer Gene Ther 2022; 29:1021-1032. [PMID: 34837065 DOI: 10.1038/s41417-021-00409-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Revised: 10/05/2021] [Accepted: 11/09/2021] [Indexed: 11/09/2022]
Abstract
Advances in the field of cancer immunotherapy have stimulated renewed interest in adenoviruses as oncolytic agents. Clinical experience has shown that oncolytic adenoviruses are safe and well tolerated but possess modest single-agent activity. One approach to improve the potency of oncolytic viruses is to utilise their tumour selectivity to deliver genes encoding prodrug-activating enzymes. These enzymes can convert prodrugs into cytotoxic species within the tumour; however, these cytotoxins can interfere with viral replication and limit utility. In this work, we evaluated the activity of a nitroreductase (NTR)-armed oncolytic adenovirus ONYX-411NTR in combination with the clinically tested bioreductive prodrug PR-104. Both NTR-expressing cells in vitro and xenografts containing a minor population of NTR-expressing cells were highly sensitive to PR-104. Pharmacologically relevant prodrug exposures did not interfere with ONYX-411NTR replication in vitro. In vivo, prodrug administration increased virus titre and improved virus distribution within tumour xenografts. Colonisation of tumours with high ONYX-411NTR titre resulted in NTR expression and prodrug activation. The combination of ONYX-411NTR with PR-104 was efficacious against HCT116 xenografts, whilst neither prodrug nor virus were active as single agents. This work highlights the potential for future clinical development of NTR-armed oncolytic viruses in combination with bioreductive prodrugs.
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Affiliation(s)
- Dean C Singleton
- Auckland Cancer Society Research Centre, University of Auckland, Auckland, New Zealand. .,Maurice Wilkins Centre for Molecular Biodiscovery, University of Auckland, Auckland, New Zealand. .,Department of Molecular Medicine and Pathology, University of Auckland, Auckland, New Zealand.
| | - Alexandra M Mowday
- Auckland Cancer Society Research Centre, University of Auckland, Auckland, New Zealand.,Maurice Wilkins Centre for Molecular Biodiscovery, University of Auckland, Auckland, New Zealand
| | - Chris P Guise
- Auckland Cancer Society Research Centre, University of Auckland, Auckland, New Zealand
| | - Sophie P Syddall
- Auckland Cancer Society Research Centre, University of Auckland, Auckland, New Zealand
| | - Sally Y Bai
- Auckland Cancer Society Research Centre, University of Auckland, Auckland, New Zealand
| | - Dan Li
- Auckland Cancer Society Research Centre, University of Auckland, Auckland, New Zealand
| | - Amir Ashoorzadeh
- Auckland Cancer Society Research Centre, University of Auckland, Auckland, New Zealand.,Maurice Wilkins Centre for Molecular Biodiscovery, University of Auckland, Auckland, New Zealand
| | - Jeff B Smaill
- Auckland Cancer Society Research Centre, University of Auckland, Auckland, New Zealand.,Maurice Wilkins Centre for Molecular Biodiscovery, University of Auckland, Auckland, New Zealand
| | - William R Wilson
- Auckland Cancer Society Research Centre, University of Auckland, Auckland, New Zealand.,Maurice Wilkins Centre for Molecular Biodiscovery, University of Auckland, Auckland, New Zealand
| | - Adam V Patterson
- Auckland Cancer Society Research Centre, University of Auckland, Auckland, New Zealand.,Maurice Wilkins Centre for Molecular Biodiscovery, University of Auckland, Auckland, New Zealand
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4
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Use of an optimised enzyme/prodrug combination for Clostridia directed enzyme prodrug therapy induces a significant growth delay in necrotic tumours. Cancer Gene Ther 2022; 29:178-188. [PMID: 33558701 DOI: 10.1038/s41417-021-00296-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Revised: 12/20/2020] [Accepted: 01/12/2021] [Indexed: 01/30/2023]
Abstract
Necrosis is a typical histological feature of solid tumours that provides a selective environment for growth of the non-pathogenic anaerobic bacterium Clostridium sporogenes. Modest anti-tumour activity as a single agent encouraged the use of C. sporogenes as a vector to express therapeutic genes selectively in tumour tissue, a concept termed Clostridium Directed Enzyme Prodrug Therapy (CDEPT). Here, we examine the ability of a recently identified Neisseria meningitidis type I nitroreductase (NmeNTR) to metabolise the prodrug PR-104A in an in vivo model of CDEPT. Human HCT116 colon cancer cells stably over-expressing NmeNTR demonstrated significant sensitivity to PR-104A, the imaging agent EF5, and several nitro(hetero)cyclic anti-infective compounds. Chemical induction of necrosis in human H1299 xenografts by the vascular disrupting agent vadimezan promoted colonisation by NmeNTR-expressing C. sporogenes, and efficacy studies demonstrated moderate but significant anti-tumour activity of spores when compared to untreated controls. Inclusion of the pre-prodrug PR-104 into the treatment schedule provided significant additional activity, indicating proof-of-principle. Successful preclinical evaluation of a transferable gene that enables metabolism of both PET imaging agents (for vector visualisation) and prodrugs (for conditional enhancement of efficacy) is an important step towards the prospect of CDEPT entering clinical evaluation.
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5
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Lai S, Kumari A, Liu J, Zhang Y, Zhang W, Yen K, Xu J. Chemical screening reveals Ronidazole is a superior prodrug to Metronidazole for nitroreductase-induced cell ablation system in zebrafish larvae. J Genet Genomics 2021; 48:1081-1090. [PMID: 34411714 DOI: 10.1016/j.jgg.2021.07.015] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2021] [Revised: 07/21/2021] [Accepted: 07/26/2021] [Indexed: 10/20/2022]
Abstract
The Metronidazole (MTZ)/nitroreductase (NTR)-mediated cell ablation system is the most commonly used chemical-genetic cell ablation method in zebrafish. This system can specifically ablate target cells under spatial and temporal control. The MTZ/NTR system has become a widely used cell ablation system in biological, developmental, and functional studies. However, the inadequate cell-ablation ability of some cell types and the side effects of high concentration MTZ impede extensive applications of the MTZ/NTR system. In the present study, the US drug collection library was searched to extend the NTR system. Six MTZ analogs were found, and the cell-ablation ability of these analogs was tested in zebrafish larvae. The results revealed that two of the NTR substrates, Furazolidone and Ronidazole, ablated target cells more efficiently than MTZ at lower concentrations. Furthermore, the working concentration of Ronidazole, but not Furazolidone and MTZ, did not affect axonal bridge formation during spinal cord regeneration. Our results, taken together, indicate that Ronidazole is a superior prodrug to MTZ for the NTR system, especially for the study of neuron regeneration in zebrafish larvae.
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Affiliation(s)
- Siting Lai
- Department of Developmental Biology, School of Basic Medical Sciences, Southern Medical University, Guangzhou 510515, China
| | - Ankita Kumari
- Division of Cell, Developmental and Integrative Biology, School of Medicine, South China University of Technology, Guangzhou 510006, China
| | - Jixiang Liu
- Division of Cell, Developmental and Integrative Biology, School of Medicine, South China University of Technology, Guangzhou 510006, China
| | - Yiyue Zhang
- Division of Cell, Developmental and Integrative Biology, School of Medicine, South China University of Technology, Guangzhou 510006, China
| | - Wenqing Zhang
- Division of Cell, Developmental and Integrative Biology, School of Medicine, South China University of Technology, Guangzhou 510006, China
| | - Kuangyu Yen
- Department of Developmental Biology, School of Basic Medical Sciences, Southern Medical University, Guangzhou 510515, China.
| | - Jin Xu
- Division of Cell, Developmental and Integrative Biology, School of Medicine, South China University of Technology, Guangzhou 510006, China.
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6
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Sharrock AV, McManaway SP, Rich MH, Mumm JS, Hermans IF, Tercel M, Pruijn FB, Ackerley DF. Engineering the Escherichia coli Nitroreductase NfsA to Create a Flexible Enzyme-Prodrug Activation System. Front Pharmacol 2021; 12:701456. [PMID: 34163368 PMCID: PMC8215503 DOI: 10.3389/fphar.2021.701456] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Accepted: 05/24/2021] [Indexed: 11/13/2022] Open
Abstract
Bacterial nitroreductase enzymes that can efficiently convert nitroaromatic prodrugs to a cytotoxic form have numerous applications in targeted cellular ablation. For example, the generation of cytotoxic metabolites that have low bystander potential (i.e., are largely confined to the activating cell) has been exploited for precise ablation of specific cell types in animal and cell-culture models; while enzyme-prodrug combinations that generate high levels of bystander cell killing are useful for anti-cancer strategies such as gene-directed enzyme-prodrug therapy (GDEPT). Despite receiving substantial attention for such applications, the canonical nitroreductase NfsB from Escherichia coli has flaws that limit its utility, in particular a low efficiency of conversion of most prodrugs. Here, we sought to engineer a superior broad-range nitroreductase, E. coli NfsA, for improved activity with three therapeutically-relevant prodrugs: the duocarmycin analogue nitro-CBI-DEI, the dinitrobenzamide aziridine CB1954 and the 5-nitroimidazole metronidazole. The former two prodrugs have applications in GDEPT, while the latter has been employed for targeted ablation experiments and as a precise 'off-switch' in GDEPT models to eliminate nitroreductase-expressing cells. Our lead engineered NfsA (variant 11_78, with the residue substitutions S41Y, L103M, K222E and R225A) generated reduced metabolites of CB1954 and nitro-CBI-DEI that exhibited high bystander efficiencies in both bacterial and 2D HEK-293 cell culture models, while no cell-to-cell transfer was evident for the reduced metronidazole metabolite. We showed that the high bystander efficiency for CB1954 could be attributed to near-exclusive generation of the 2-hydroxylamine reduction product, which has been shown in 3D cell culture to cause significantly greater bystander killing than the 4-hydroxylamine species that is also produced by NfsB. We similarly observed a high bystander effect for nitro-CBI-DEI in HCT-116 tumor spheroids in which only a small proportion of cells were expressing variant 11_78. Collectively, our data identify variant 11_78 as a broadly improved prodrug-activating nitroreductase that offers advantages for both targeted cellular ablation and suicide gene therapy applications.
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Affiliation(s)
- Abigail V. Sharrock
- School of Biological Sciences, Victoria University of Wellington, Wellington, New Zealand
- Centre for Biodiscovery, Victoria University of Wellington, Wellington, New Zealand
- Maurice Wilkins Centre for Molecular Biodiscovery, Auckland, New Zealand
| | - Sarah P. McManaway
- Auckland Cancer Society Research Centre, The University of Auckland, Auckland, New Zealand
| | - Michelle H. Rich
- School of Biological Sciences, Victoria University of Wellington, Wellington, New Zealand
| | - Jeff S. Mumm
- The Wilmer Eye Institute, Johns Hopkins University, Baltimore, MD, United States
| | - Ian F. Hermans
- School of Biological Sciences, Victoria University of Wellington, Wellington, New Zealand
- Maurice Wilkins Centre for Molecular Biodiscovery, Auckland, New Zealand
- Malaghan Institute of Medical Research, Wellington, New Zealand
| | - Moana Tercel
- Maurice Wilkins Centre for Molecular Biodiscovery, Auckland, New Zealand
- Auckland Cancer Society Research Centre, The University of Auckland, Auckland, New Zealand
| | - Frederik B. Pruijn
- Maurice Wilkins Centre for Molecular Biodiscovery, Auckland, New Zealand
- Auckland Cancer Society Research Centre, The University of Auckland, Auckland, New Zealand
| | - David F. Ackerley
- School of Biological Sciences, Victoria University of Wellington, Wellington, New Zealand
- Centre for Biodiscovery, Victoria University of Wellington, Wellington, New Zealand
- Maurice Wilkins Centre for Molecular Biodiscovery, Auckland, New Zealand
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7
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The YfkO Nitroreductase from Bacillus Licheniformis on Gold-Coated Superparamagnetic Nanoparticles: Towards a Novel Directed Enzyme Prodrug Therapy Approach. Pharmaceutics 2021; 13:pharmaceutics13040517. [PMID: 33918536 PMCID: PMC8070144 DOI: 10.3390/pharmaceutics13040517] [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: 03/09/2021] [Revised: 03/25/2021] [Accepted: 03/26/2021] [Indexed: 11/17/2022] Open
Abstract
The bacterial nitroreductase NfnB has been the focus of a great deal of research for its use in directed enzyme prodrug therapy in combination with the nitroreductase prodrug CB1954 with this combination of enzyme and prodrug even entering clinical trials. Despite some promising results, there are major limitations to this research, such as the fact that the lowest reported Km for this enzyme far exceeds the maximum dosage of CB1954. Due to these limitations, new enzymes are now being investigated for their potential use in directed enzyme prodrug therapy. One such enzyme that has proved promising is the YfkO nitroreductase from Bacillus Licheniformis. Upon investigation, the YfkO nitroreductase was shown to have a much lower Km (below the maximum dosage) than that of NfnB as well as the fact that when reacting with the prodrug it produces a much more favourable ratio of enzymatic products than NfnB, forming more of the desired 4-hydroxylamine derivative of CB1954.
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8
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Ball P, Halliwell J, Anderson S, Gwenin V, Gwenin C. Evaluation of two xenobiotic reductases from Pseudomonas putida for their suitability for magnetic nanoparticle-directed enzyme prodrug therapy as a novel approach to cancer treatment. Microbiologyopen 2020; 9:e1110. [PMID: 32979040 PMCID: PMC7568253 DOI: 10.1002/mbo3.1110] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Revised: 07/28/2020] [Accepted: 07/30/2020] [Indexed: 02/03/2023] Open
Abstract
Directed enzyme prodrug therapy (DEPT) is a cancer chemotherapy strategy in which bacterial enzymes are delivered to a cancer site before prodrug administration, resulting in prodrug activation at the cancer site and more localized treatment. A major limitation to DEPT is the poor effectiveness of the most studied enzyme for the CB1954 prodrug, NfnB from Escherichia coli, at concentrations suitable for human use. Much research into finding alternative enzymes to NfnB has resulted in the identification of the Xenobiotic reductases, XenA and XenB, which have been shown in the literature to reduce environmentally polluting nitro‐compounds. In this study, they were assessed for their potential use in cancer prodrug therapy strategies. Both proteins were cloned into the pET28a+ expression vector to give the genetically modified proteins XenA‐his and XenB‐his, of which only XenB‐his was active when tested with CB1954. XenB‐his was further modified to include a cysteine‐tag to facilitate direct immobilization on to a gold surface for future magnetic nanoparticle DEPT (MNDEPT) treatments and was named XenB‐cys. When tested using high‐performance liquid chromatography (HPLC), XenB‐his and XenB‐cys both demonstrated a preference for reducing CB1954 at the 4‐nitro position. Furthermore, XenB‐his and XenB‐cys successfully induced cell death in SK‐OV‐3 cells when combined with CB1954. This led to XenB‐cys being identified as a promising candidate for use in future MNDEPT treatments.
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9
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Forterre AV, Wang JH, Delcayre A, Kim K, Green C, Pegram MD, Jeffrey SS, Matin AC. Extracellular Vesicle-Mediated In Vitro Transcribed mRNA Delivery for Treatment of HER2 + Breast Cancer Xenografts in Mice by Prodrug CB1954 without General Toxicity. Mol Cancer Ther 2020; 19:858-867. [PMID: 31941722 DOI: 10.1158/1535-7163.mct-19-0928] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 12/02/2019] [Accepted: 01/08/2020] [Indexed: 02/06/2023]
Abstract
Prodrugs are harmless until activated by a bacterial or viral gene product; they constitute the basis of gene-delivered prodrug therapies called GDEPT, which can kill tumors without major side effects. Previously, we utilized the prodrug CNOB (C16H7CIN2O4; not clinically tested) and enzyme HChrR6 in GDEPT to generate the drug MCHB (C16H9CIN2O2) in tumors. Extracellular vesicles (EVs) were used for directed gene delivery and HChrR6 mRNA as gene. Here, the clinical transfer of this approach is enhanced by: (i) use of CB1954 (tretazicar) for which safe human dose is established; HChrR6 can activate this prodrug. (ii) EVs delivered in vitro transcribed (IVT) HChrR6 mRNA, eliminating the potentially harmful plasmid transfection of EV producer cells we utilized previously; this has not been done before. IVT mRNA loading of EVs required several steps. Naked mRNA being unstable, we ensured its prodrug activating functionality at each step. This was not possible using tretazicar itself; we relied instead on HChrR6's ability to convert CNOB into MCHB, whose fluorescence is easily visualizable. HChrR6 mRNA-translated product's ability to generate fluorescence from CNOB vicariously indicated its competence for tretazicar activation. (iii) Systemic IVT mRNA-loaded EVs displaying an anti-HER2 single-chain variable fragment ("IVT EXO-DEPTs") and tretazicar caused growth arrest of human HER2+ breast cancer xenografts in athymic mice. As this occurred without injury to other tissues, absence of off-target mRNA delivery is strongly indicated. Many cancer sites are not amenable for direct gene injection, but current GDEPTs require this. In circumventing this need, a major advance in GDEPT applicability has been accomplished.
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Affiliation(s)
- Alexis V Forterre
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, California
| | - Jing-Hung Wang
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, California
| | | | - Kyuri Kim
- SRI International, Menlo Park, California
| | | | - Mark D Pegram
- Department of Medicine, Stanford University School of Medicine, Stanford, California
| | - Stefanie S Jeffrey
- Department of Surgery, Stanford University School of Medicine, Stanford, California
| | - A C Matin
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, California.
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10
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Liu F, Dai S, Feng D, Peng X, Qin Z, Kearns AC, Huang W, Chen Y, Ergün S, Wang H, Rappaport J, Bryda EC, Chandrasekhar A, Aktas B, Hu H, Chang SL, Gao B, Qin X. Versatile cell ablation tools and their applications to study loss of cell functions. Cell Mol Life Sci 2019; 76:4725-4743. [PMID: 31359086 PMCID: PMC6858955 DOI: 10.1007/s00018-019-03243-w] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Revised: 07/17/2019] [Accepted: 07/22/2019] [Indexed: 12/22/2022]
Abstract
Targeted cell ablation is a powerful approach for studying the role of specific cell populations in a variety of organotypic functions, including cell differentiation, and organ generation and regeneration. Emerging tools for permanently or conditionally ablating targeted cell populations and transiently inhibiting neuronal activities exhibit a diversity of application and utility. Each tool has distinct features, and none can be universally applied to study different cell types in various tissue compartments. Although these tools have been developed for over 30 years, they require additional improvement. Currently, there is no consensus on how to select the tools to answer the specific scientific questions of interest. Selecting the appropriate cell ablation technique to study the function of a targeted cell population is less straightforward than selecting the method to study a gene's functions. In this review, we discuss the features of the various tools for targeted cell ablation and provide recommendations for optimal application of specific approaches.
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Affiliation(s)
- Fengming Liu
- Department of Neuroscience, Lewis Katz School of Medicine at Temple University, 3500 N Broad Street, Philadelphia, PA, 19140, USA
- Division of Comparative Pathology, Tulane National Primate Research Center, Covington, LA, 70433, USA
- Department of Immunology and Microbiology, Tulane University School of Medicine, New Orleans, LA, 70112, USA
| | - Shen Dai
- Department of Neuroscience, Lewis Katz School of Medicine at Temple University, 3500 N Broad Street, Philadelphia, PA, 19140, USA
| | - Dechun Feng
- Laboratory of Liver Diseases, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Xiao Peng
- Department of Neuroscience, Lewis Katz School of Medicine at Temple University, 3500 N Broad Street, Philadelphia, PA, 19140, USA
| | - Zhongnan Qin
- Department of Neuroscience, Lewis Katz School of Medicine at Temple University, 3500 N Broad Street, Philadelphia, PA, 19140, USA
- Division of Comparative Pathology, Tulane National Primate Research Center, Covington, LA, 70433, USA
- Department of Immunology and Microbiology, Tulane University School of Medicine, New Orleans, LA, 70112, USA
| | - Alison C Kearns
- Department of Neuroscience, Lewis Katz School of Medicine at Temple University, 3500 N Broad Street, Philadelphia, PA, 19140, USA
| | - Wenfei Huang
- Institute of NeuroImmune Pharmacology, Seton Hall University, 400 South Orange Avenue, South Orange, NJ, 07079, USA
| | - Yong Chen
- Department of Neuroscience, Lewis Katz School of Medicine at Temple University, 3500 N Broad Street, Philadelphia, PA, 19140, USA
- Key Lab for Immunology in Universities of Shandong Province, School of Clinical Medicine, Weifang Medical University, 261053, Weifang, People's Republic of China
| | - Süleyman Ergün
- Institute of Anatomy and Cell Biology, Julius-Maximillan University, 97070, Wurzburg, Germany
| | - Hong Wang
- Department of Neuroscience, Lewis Katz School of Medicine at Temple University, 3500 N Broad Street, Philadelphia, PA, 19140, USA
| | - Jay Rappaport
- Division of Pathology, Tulane National Primate Research Center, 18703 Three Rivers Road, Covington, LA, 70433, USA
| | - Elizabeth C Bryda
- Rat Resource and Research Center, University of Missouri, 4011 Discovery Drive, Columbia, MO, 65201, USA
| | - Anand Chandrasekhar
- Division of Biological Sciences, 340D Life Sciences Center, University of Missouri, 1201 Rollins St, Columbia, MO, USA
| | - Bertal Aktas
- Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, 02115, USA
| | - Hongzhen Hu
- Department of Anesthesiology, Center for the Study of Itch, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Sulie L Chang
- Institute of NeuroImmune Pharmacology, Seton Hall University, 400 South Orange Avenue, South Orange, NJ, 07079, USA
| | - Bin Gao
- Laboratory of Liver Diseases, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Xuebin Qin
- Department of Neuroscience, Lewis Katz School of Medicine at Temple University, 3500 N Broad Street, Philadelphia, PA, 19140, USA.
- Division of Comparative Pathology, Tulane National Primate Research Center, Covington, LA, 70433, USA.
- Department of Immunology and Microbiology, Tulane University School of Medicine, New Orleans, LA, 70112, USA.
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11
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Anderson SD, Hobbs RJ, Gwenin VV, Ball P, Bennie LA, Coulter JA, Gwenin CD. Cell-Penetrating Peptides as a Tool for the Cellular Uptake of a Genetically Modified Nitroreductase for use in Directed Enzyme Prodrug Therapy. J Funct Biomater 2019; 10:E45. [PMID: 31581475 PMCID: PMC6963571 DOI: 10.3390/jfb10040045] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Revised: 09/30/2019] [Accepted: 09/30/2019] [Indexed: 11/16/2022] Open
Abstract
Directed enzyme prodrug therapy (DEPT) involves the delivery of a prodrug-activating enzyme to a solid tumour site, followed by the subsequent activation of an administered prodrug. One of the most studied enzyme-prodrug combinations is the nitroreductase from Escherichia coli (NfnB) with the prodrug CB1954 [5-(aziridin-1-yl)-2,4-dinitro-benzamide]. One of the major issues faced by DEPT is the ability to successfully internalize the enzyme into the target cells. NfnB has previously been genetically modified to contain cysteine residues (NfnB-Cys) which bind to gold nanoparticles for a novel DEPT therapy called magnetic nanoparticle directed enzyme prodrug therapy (MNDEPT). One cellular internalisation method is the use of cell-penetrating peptides (CPPs), which aid cellular internalization of cargo. Here the cell-penetrating peptides: HR9 and Pep-1 were tested for their ability to conjugate with NfnB-Cys. The conjugates were further tested for their potential use in MNDEPT, as well as conjugating with the delivery vector intended for use in MNDEPT and tested for the vectors capability to penetrate into cells.
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Affiliation(s)
- Simon D Anderson
- School of Natural Sciences, Bangor University, Bangor, Gwynedd, LL57 2DG Wales, UK.
| | - Robert J Hobbs
- School of Natural Sciences, Bangor University, Bangor, Gwynedd, LL57 2DG Wales, UK.
| | - Vanessa V Gwenin
- School of Natural Sciences, Bangor University, Bangor, Gwynedd, LL57 2DG Wales, UK.
| | - Patrick Ball
- School of Natural Sciences, Bangor University, Bangor, Gwynedd, LL57 2DG Wales, UK.
| | - Lindsey A Bennie
- School of Pharmacy, Queen's University Belfast, BT7 1NN Belfast, UK.
| | | | - Chris D Gwenin
- School of Natural Sciences, Bangor University, Bangor, Gwynedd, LL57 2DG Wales, UK.
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Güngör T, Önder FC, Tokay E, Gülhan ÜG, Hacıoğlu N, Tok TT, Çelik A, Köçkar F, Ay M. PRODRUGS FOR NITROREDUCTASE BASED CANCER THERAPY- 2: Novel amide/Ntr combinations targeting PC3 cancer cells. Eur J Med Chem 2019; 171:383-400. [DOI: 10.1016/j.ejmech.2019.03.035] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2018] [Revised: 02/26/2019] [Accepted: 03/14/2019] [Indexed: 02/06/2023]
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13
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Ball P, Thompson E, Anderson S, Gwenin V, Gwenin C. Time dependent HPLC analysis of the product ratio of enzymatically reduced prodrug CB1954 by a modified and immobilised nitroreductase. Eur J Pharm Sci 2018; 127:217-224. [PMID: 30414836 DOI: 10.1016/j.ejps.2018.11.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Revised: 10/25/2018] [Accepted: 11/01/2018] [Indexed: 02/01/2023]
Abstract
Directed enzyme prodrug therapy is a chemotherapy strategy that utilises prodrug-activating enzymes to activate prodrugs at the tumour location, thus reducing off-target effects. The most commonly investigated enzyme for use with the CB1954 prodrug is the NfnB nitroreductase from E. coli. Literature states that CB1954 is reduced by NfnB at the 2- or 4-position at a 1:1 ratio; deviation from this ratio has been observed in the literature, but not further investigated. The kinetic parameters for the genetically-modified enzymes; NfnB-his, NfnB-cys and AuNP-NfnB-cys were assessed and HPLC analysis was used to determine the hydroxylamine product ratios formed when reacted with CB1954. Time-dependent HPLC studies were carried out to assess how this ratio changes over time. It was shown that the hydroxylamine ratio formed by the reduction of CB1954 by a nitroreductase changes over time and that this change in ratio relates directly to the kinetics of the reaction. Thus, the hydroxylamine ratio measured using HPLC at a given time point was not a true indication of the preference of the nitroreductase enzymes during catalysis. These results question how nitroreductases are evaluated in terms of the hydroxylamine ratio and it is suspected that this phenomenon may also apply to other enzyme/prodrug combinations.
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Affiliation(s)
- Patrick Ball
- College of Environmental Sciences and Engineering, School of Natural Sciences, Chemistry Bangor University, LL57 2DG, United Kingdom of Great Britain and Northern Ireland
| | - Emma Thompson
- College of Environmental Sciences and Engineering, School of Natural Sciences, Chemistry Bangor University, LL57 2DG, United Kingdom of Great Britain and Northern Ireland
| | - Simon Anderson
- College of Environmental Sciences and Engineering, School of Natural Sciences, Chemistry Bangor University, LL57 2DG, United Kingdom of Great Britain and Northern Ireland
| | - Vanessa Gwenin
- College of Environmental Sciences and Engineering, School of Natural Sciences, Chemistry Bangor University, LL57 2DG, United Kingdom of Great Britain and Northern Ireland
| | - Chris Gwenin
- College of Environmental Sciences and Engineering, School of Natural Sciences, Chemistry Bangor University, LL57 2DG, United Kingdom of Great Britain and Northern Ireland.
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14
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Evaluating the abilities of diverse nitroaromatic prodrug metabolites to exit a model Gram negative vector for bacterial-directed enzyme-prodrug therapy. Biochem Pharmacol 2018; 158:192-200. [PMID: 30352235 DOI: 10.1016/j.bcp.2018.10.020] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Accepted: 10/17/2018] [Indexed: 12/12/2022]
Abstract
Gene-directed enzyme-prodrug therapy (GDEPT) employs tumour-tropic vectors including viruses and bacteria to deliver a genetically-encoded prodrug-converting enzyme to the tumour environment, thereby sensitising the tumour to the prodrug. Nitroreductases, able to activate a range of promising nitroaromatic prodrugs to genotoxic metabolites, are of great interest for GDEPT. The bystander effect (cell-to-cell transfer of activated prodrug metabolites) has been quantified for some nitroaromatic prodrugs in mixed multilayer human cell cultures, however while these provide a good model for viral DEPT (VDEPT) they do not inform on the ability of these prodrug metabolites to exit bacterial vectors (relevant to bacterial-DEPT (BDEPT)). To investigate this we grew two Escherichia coli strains in co-culture; an activator strain expressing the nitroreductase E. coli NfsA and a recipient strain containing an SOS-GFP DNA damage responsive gene construct. In this system, induction of GFP by reduced prodrug metabolites can only occur following their transfer from the activator to the recipient cells. We used this to investigate five clinically relevant prodrugs: metronidazole, CB1954, nitro-CBI-DEI, and two dinitrobenzamide mustard prodrug analogues, PR-104A and SN27686. Consistent with the bystander efficiencies previously measured in human cell multilayers, reduced metronidazole exhibited little bacterial cell-to-cell transfer, whereas nitro-CBI-DEI was passed very efficiently from activator to recipient cells post-reduction. However, in contrast with observations in human cell multilayers, the nitrogen mustard prodrug metabolites were not effectively passed between the two bacterial strains, whereas reduced CB1954 was transferred efficiently. Using nitroreductase enzymes that exhibit different biases for the 2- versus 4-nitro substituents of CB1954, we further showed that the 2-nitro reduction products exhibit substantially higher levels of bacterial cell-to-cell transfer than the 4-nitro reduction products, consistent with their relative bystander efficiencies in human cell culture. Overall, our data suggest that prodrugs may differ in their suitability for VDEPT versus BDEPT applications and emphasise the importance of evaluating an enzyme-prodrug partnership in an appropriate context for the intended vector.
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15
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Hong CR, Bogle G, Wang J, Patel K, Pruijn FB, Wilson WR, Hicks KO. Bystander Effects of Hypoxia-Activated Prodrugs: Agent-Based Modeling Using Three Dimensional Cell Cultures. Front Pharmacol 2018; 9:1013. [PMID: 30279659 PMCID: PMC6153434 DOI: 10.3389/fphar.2018.01013] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Accepted: 08/20/2018] [Indexed: 12/19/2022] Open
Abstract
Intra-tumor heterogeneity represents a major barrier to anti-cancer therapies. One strategy to minimize this limitation relies on bystander effects via diffusion of cytotoxins from targeted cells. Hypoxia-activated prodrugs (HAPs) have the potential to exploit hypoxia in this way, but robust methods for measuring bystander effects are lacking. The objective of this study is to develop experimental models (monolayer, multilayer, and multicellular spheroid co-cultures) comprising 'activator' cells with high expression of prodrug-activating reductases and reductase-deficient 'target' cells, and to couple these with agent-based models (ABMs) that describe diffusion and reaction of prodrugs and their active metabolites, and killing probability for each cell. HCT116 cells were engineered as activators by overexpressing P450 oxidoreductase (POR) and as targets by knockout of POR, with fluorescent protein and antibiotic resistance markers to enable their quantitation in co-cultures. We investigated two HAPs with very different pharmacology: SN30000 is metabolized to DNA-breaking free radicals under hypoxia, while the dinitrobenzamide PR104A generates DNA-crosslinking nitrogen mustard metabolites. In anoxic spheroid co-cultures, increasing the proportion of activator cells decreased killing of both activators and targets by SN30000. An ABM parameterized by measuring SN30000 cytotoxicity in monolayers and diffusion-reaction in multilayers accurately predicted SN30000 activity in spheroids, demonstrating the lack of bystander effects and that rapid metabolic consumption of SN30000 inhibited prodrug penetration. In contrast, killing of targets by PR104A in anoxic spheroids was markedly increased by activators, demonstrating that a bystander effect more than compensates any penetration limitation. However, the ABM based on the well-studied hydroxylamine and amine metabolites of PR104A did not fit the cell survival data, indicating a need to reassess its cellular pharmacology. Characterization of extracellular metabolites of PR104A in anoxic cultures identified more stable, lipophilic, activated dichloro mustards with greater tissue diffusion distances. Including these metabolites explicitly in the ABM provided a good description of activator and target cell killing by PR104A in spheroids. This study represents the most direct demonstration of a hypoxic bystander effect for PR104A to date, and demonstrates the power of combining mathematical modeling of pharmacokinetics/pharmacodynamics with multicellular culture models to dissect bystander effects of targeted drug carriers.
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Affiliation(s)
- Cho R. Hong
- Auckland Cancer Society Research Centre, University of Auckland, Auckland, New Zealand
| | - Gib Bogle
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
- Maurice Wilkins Centre, University of Auckland, Auckland, New Zealand
| | - Jingli Wang
- Auckland Cancer Society Research Centre, University of Auckland, Auckland, New Zealand
| | - Kashyap Patel
- Auckland Cancer Society Research Centre, University of Auckland, Auckland, New Zealand
| | - Frederik B. Pruijn
- Auckland Cancer Society Research Centre, University of Auckland, Auckland, New Zealand
| | - William R. Wilson
- Auckland Cancer Society Research Centre, University of Auckland, Auckland, New Zealand
- Maurice Wilkins Centre, University of Auckland, Auckland, New Zealand
| | - Kevin O. Hicks
- Auckland Cancer Society Research Centre, University of Auckland, Auckland, New Zealand
- Maurice Wilkins Centre, University of Auckland, Auckland, New Zealand
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16
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Rich MH, Sharrock AV, Hall KR, Ackerley DF, MacKichan JK. Evaluation of NfsA-like nitroreductases from Neisseria meningitidis and Bartonella henselae for enzyme-prodrug therapy, targeted cellular ablation, and dinitrotoluene bioremediation. Biotechnol Lett 2017; 40:359-367. [DOI: 10.1007/s10529-017-2472-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2017] [Accepted: 10/31/2017] [Indexed: 10/18/2022]
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17
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Šarlauskas J, Tamulienė J, Čėnas N. Aziridinyl-substituted benzo-1,4-quinones: A preliminary investigation on the theoretical and experimental studies of their structure and spectroscopic properties. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2017; 178:136-141. [PMID: 28182983 DOI: 10.1016/j.saa.2017.01.058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2016] [Revised: 01/24/2017] [Accepted: 01/25/2017] [Indexed: 06/06/2023]
Abstract
The detailed structure, chemical and spectroscopic properties of the derivatives of the selected 2,5-bis(1-aziridinyl)-benzo-1,4-quinone conformers were studied by applying quantum chemical and experimental methods. The relationship between the structure and chemical activity of the selected 3 bifunctional bioreductive quinonic anticancer agents - aziridinyl benzoquinones (AzBQ compounds) was obtained. The results obtained showed that the position of aziridine rings influenced by the chemical activity of the investigated compound were more significant than the substitutions of the benzene ring of the AzBQ compounds. The solvents influencing this activity were obtained, too.
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Affiliation(s)
- Jonas Šarlauskas
- Vilnius University, Instituteof Biochemistry, Sauletekio av. 7, Vilnius LT-10222, Lithuania.
| | - Jelena Tamulienė
- Vilnius University, Institute of Theoretical Physics and Astronomy, Sauletekio av. 3, Vilnius, LT-10222, Lithuania.
| | - Narimantas Čėnas
- Vilnius University, Instituteof Biochemistry, Sauletekio av. 7, Vilnius LT-10222, Lithuania
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18
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Burke PJ, Wong LC, Jenkins TC, Knox RJ, Meikle IT, Stanforth SP. Studies relating to the synthesis, enzymatic reduction and cytotoxicity of a series of nitroaromatic prodrugs. Bioorg Med Chem Lett 2016; 26:5851-5854. [PMID: 27876476 DOI: 10.1016/j.bmcl.2016.11.024] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2016] [Revised: 11/10/2016] [Accepted: 11/10/2016] [Indexed: 11/17/2022]
Abstract
A series of N-nitroarylated-3-chloromethyl-1,2,3,4-tetrahydroisoquinoline derivatives, several of which also possessed a trifluoromethyl substituent, were prepared and assessed as potential nitroaromatic prodrugs. The enzymatic reduction of these compounds and their cytotoxicities were studied. The compounds were cytotoxic, but this is probably not related to their enzymatic reduction.
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Affiliation(s)
- Philip J Burke
- Morvus Technology Ltd, Llanvetherine Court, Llanvetherine, Abergavenny NP7 8NL, UK
| | - Lai Chun Wong
- Department of Applied Sciences, University of Northumbria, Newcastle-upon-Tyne NE1 8ST, UK
| | - Terence C Jenkins
- Morvus Technology Ltd, Llanvetherine Court, Llanvetherine, Abergavenny NP7 8NL, UK
| | - Richard J Knox
- Morvus Technology Ltd, Llanvetherine Court, Llanvetherine, Abergavenny NP7 8NL, UK
| | - Ian T Meikle
- Department of Applied Sciences, University of Northumbria, Newcastle-upon-Tyne NE1 8ST, UK
| | - Stephen P Stanforth
- Department of Applied Sciences, University of Northumbria, Newcastle-upon-Tyne NE1 8ST, UK.
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19
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Nitroreductase gene-directed enzyme prodrug therapy: insights and advances toward clinical utility. Biochem J 2015; 471:131-53. [PMID: 26431849 DOI: 10.1042/bj20150650] [Citation(s) in RCA: 95] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
This review examines the vast catalytic and therapeutic potential offered by type I (i.e. oxygen-insensitive) nitroreductase enzymes in partnership with nitroaromatic prodrugs, with particular focus on gene-directed enzyme prodrug therapy (GDEPT; a form of cancer gene therapy). Important first indications of this potential were demonstrated over 20 years ago, for the enzyme-prodrug pairing of Escherichia coli NfsB and CB1954 [5-(aziridin-1-yl)-2,4-dinitrobenzamide]. However, it has become apparent that both the enzyme and the prodrug in this prototypical pairing have limitations that have impeded their clinical progression. Recently, substantial advances have been made in the biodiscovery and engineering of superior nitroreductase variants, in particular development of elegant high-throughput screening capabilities to enable optimization of desirable activities via directed evolution. These advances in enzymology have been paralleled by advances in medicinal chemistry, leading to the development of second- and third-generation nitroaromatic prodrugs that offer substantial advantages over CB1954 for nitroreductase GDEPT, including greater dose-potency and enhanced ability of the activated metabolite(s) to exhibit a local bystander effect. In addition to forging substantial progress towards future clinical trials, this research is supporting other fields, most notably the development and improvement of targeted cellular ablation capabilities in small animal models, such as zebrafish, to enable cell-specific physiology or regeneration studies.
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20
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Lehouritis P, Stanton M, McCarthy FO, Jeavons M, Tangney M. Activation of multiple chemotherapeutic prodrugs by the natural enzymolome of tumour-localised probiotic bacteria. J Control Release 2015; 222:9-17. [PMID: 26655063 DOI: 10.1016/j.jconrel.2015.11.030] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2015] [Revised: 11/26/2015] [Accepted: 11/27/2015] [Indexed: 12/15/2022]
Abstract
Some chemotherapeutic drugs (prodrugs) require activation by an enzyme for efficacy. We and others have demonstrated the ability of probiotic bacteria to grow specifically within solid tumours following systemic administration, and we hypothesised that the natural enzymatic activity of these tumour-localised bacteria may be suitable for activation of certain such chemotherapeutic drugs. Several wild-type probiotic bacteria; Escherichia coli Nissle, Bifidobacterium breve, Lactococcus lactis and Lactobacillus species, were screened against a panel of popular prodrugs. All strains were capable of activating at least one prodrug. E. coli Nissle 1917 was selected for further studies because of its ability to activate numerous prodrugs and its resistance to prodrug toxicity. HPLC data confirmed biochemical transformation of prodrugs to their toxic counterparts. Further analysis demonstrated that different enzymes can complement prodrug activation, while simultaneous activation of multiple prodrugs (CB1954, 5-FC, AQ4N and Fludarabine phosphate) by E. coli was confirmed, resulting in significant efficacy improvement. Experiments in mice harbouring murine tumours validated in vitro findings, with significant reduction in tumour growth and increase in survival of mice treated with probiotic bacteria and a combination of prodrugs. These findings demonstrate the ability of probiotic bacteria, without the requirement for genetic modification, to enable high-level activation of multiple prodrugs specifically at the site of action.
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Affiliation(s)
- Panos Lehouritis
- Cork Cancer Research Centre, University College Cork, Cork, Ireland
| | - Michael Stanton
- Cork Cancer Research Centre, University College Cork, Cork, Ireland
| | - Florence O McCarthy
- Department of Chemistry and Analytical and Biological Chemistry Research Facility, University College Cork, Cork, Ireland
| | - Matthieu Jeavons
- Cork Cancer Research Centre, University College Cork, Cork, Ireland
| | - Mark Tangney
- Cork Cancer Research Centre, University College Cork, Cork, Ireland.
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21
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Local bacteria affect the efficacy of chemotherapeutic drugs. Sci Rep 2015; 5:14554. [PMID: 26416623 PMCID: PMC4586607 DOI: 10.1038/srep14554] [Citation(s) in RCA: 180] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Accepted: 08/18/2015] [Indexed: 12/30/2022] Open
Abstract
In this study, the potential effects of bacteria on the efficacy of frequently used chemotherapies was examined. Bacteria and cancer cell lines were examined in vitro and in vivo for changes in the efficacy of cancer cell killing mediated by chemotherapeutic agents. Of 30 drugs examined in vitro, the efficacy of 10 was found to be significantly inhibited by certain bacteria, while the same bacteria improved the efficacy of six others. HPLC and mass spectrometry analyses of sample drugs (gemcitabine, fludarabine, cladribine, CB1954) demonstrated modification of drug chemical structure. The chemoresistance or increased cytotoxicity observed in vitro with sample drugs (gemcitabine and CB1954) was replicated in in vivo murine subcutaneous tumour models. These findings suggest that bacterial presence in the body due to systemic or local infection may influence tumour responses or off-target toxicity during chemotherapy.
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Gwenin VV, Poornima P, Halliwell J, Ball P, Robinson G, Gwenin CD. Identification of novel nitroreductases from Bacillus cereus and their interaction with the CB1954 prodrug. Biochem Pharmacol 2015; 98:392-402. [PMID: 26415543 DOI: 10.1016/j.bcp.2015.09.013] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Accepted: 09/15/2015] [Indexed: 10/23/2022]
Abstract
Directed enzyme prodrug therapy is a form of cancer chemotherapy in which bacterial prodrug-activating enzymes, or their encoding genes, are directed to the tumour before administration of a prodrug. The prodrug can then be activated into a toxic drug at the tumour site, reducing off-target effects. The bacterial nitroreductases are a class of enzymes used in this therapeutic approach and although very promising, the low turnover rate of prodrug by the most studied nitroreductase enzyme, NfnB from Escherichia coli (NfnB_Ec), is a major limit to this technology. There is a continual search for enzymes with greater efficiency, and as part of the search for more efficient bacterial nitroreductase enzymes, two novel enzymes from Bacillus cereus (strain ATCC 14579) have been identified and shown to reduce the CB1954 (5-(aziridin-1-yl)-2,4-dinitrobenzamide) prodrug to its respective 2'-and 4'-hydroxylamine products. Both enzymes shared features characteristic of the nitro-FMN-reductase superfamily including non-covalently associated FMN, requirement for the NAD(P)H cofactor, homodimeric, could be inhibited by Dicoumarol (3,3'-methylenebis(4-hydroxy-2H-chromen-2-one)), and displayed ping pong bi bi kinetics. Based on the biochemical characteristics and nucleotide alignment with other nitroreductase enzymes, one enzyme was named YdgI_Bc and the other YfkO_Bc. Both B. cereus enzymes had greater turnover for the CB1954 prodrug compared with NfnB_Ec, and in the presence of added NADPH cofactor, YfkO_Bc had superior cell killing ability, and produced mainly the 4'-hydroxylamine product at low prodrug concentration. The YfkO_Bc was identified as a promising candidate for future enzyme prodrug therapy.
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Affiliation(s)
- Vanessa V Gwenin
- School of Chemistry, Bangor University, Bangor, Gwynedd, LL57 2DG Wales, UK
| | | | - Jennifer Halliwell
- School of Chemistry, Bangor University, Bangor, Gwynedd, LL57 2DG Wales, UK
| | - Patrick Ball
- School of Chemistry, Bangor University, Bangor, Gwynedd, LL57 2DG Wales, UK
| | - George Robinson
- School of Chemistry, Bangor University, Bangor, Gwynedd, LL57 2DG Wales, UK
| | - Chris D Gwenin
- School of Chemistry, Bangor University, Bangor, Gwynedd, LL57 2DG Wales, UK.
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23
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Porterfield WB, Jones KA, McCutcheon DC, Prescher JA. A “Caged” Luciferin for Imaging Cell–Cell Contacts. J Am Chem Soc 2015; 137:8656-9. [DOI: 10.1021/jacs.5b02774] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- William B. Porterfield
- Departments of Chemistry, ‡Molecular Biology & Biochemistry, and §Pharmaceutical Sciences, University of California, Irvine, California 92697, United States
| | - Krysten A. Jones
- Departments of Chemistry, ‡Molecular Biology & Biochemistry, and §Pharmaceutical Sciences, University of California, Irvine, California 92697, United States
| | - David C. McCutcheon
- Departments of Chemistry, ‡Molecular Biology & Biochemistry, and §Pharmaceutical Sciences, University of California, Irvine, California 92697, United States
| | - Jennifer A. Prescher
- Departments of Chemistry, ‡Molecular Biology & Biochemistry, and §Pharmaceutical Sciences, University of California, Irvine, California 92697, United States
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24
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Sheng H, Tang W, Yerabolu R, Kong JY, Williams PE, Zhang M, Kenttämaa HI. Mass spectrometric identification of the N-monosubstituted N-hydroxylamino functionality in protonated analytes via ion/molecule reactions in tandem mass spectrometry. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2015; 29:730-734. [PMID: 26406487 DOI: 10.1002/rcm.7154] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2014] [Revised: 01/24/2015] [Accepted: 01/24/2015] [Indexed: 06/05/2023]
Abstract
RATIONALE N-Monosubstituted hydroxylamines correspond to an important class of metabolites for many bioactive molecules. In this study, a tandem mass spectrometric method based on ion/molecule reactions was developed for the identification of compounds with the N-monosubstituted hydroxylamino functionality. METHODS The diagnostic ion/molecule reaction occurs between protonated analytes with 2-methoxypropene (MOP) inside a linear quadrupole ion trap mass spectrometer. RESULTS Most protonated compounds with N-monosubstituted and disubstituted hydroxylamino and oxime functional groups react with MOP via proton transfer and formation of a stable adduct in a linear quadrupole ion trap mass spectrometer. However, only protonated compounds with N-monosubstituted hydroxylamino groups form the characteristic MOP adduct-MeOH product. Possible mechanisms of this reaction are discussed. CONCLUSIONS A method based on functional group-selective ion/molecule reactions in a linear quadrupole ion trap mass spectrometer has been demonstrated to allow the identification of protonated compounds with the N-monosubstituted hydroxylamino functionality. Only N-monosubstituted hydroxylamines react with MOP via formation of an adduct that has eliminated methanol.
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Affiliation(s)
- Huaming Sheng
- Purdue University, Department of Chemistry, West Lafayette, IN, 47907, USA
| | - Weijuan Tang
- Purdue University, Department of Chemistry, West Lafayette, IN, 47907, USA
| | - Ravikiran Yerabolu
- Purdue University, Department of Chemistry, West Lafayette, IN, 47907, USA
| | - John Y Kong
- Purdue University, Department of Chemistry, West Lafayette, IN, 47907, USA
| | - Peggy E Williams
- Purdue University, Department of Chemistry, West Lafayette, IN, 47907, USA
| | | | - Hilkka I Kenttämaa
- Purdue University, Department of Chemistry, West Lafayette, IN, 47907, USA
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Abstract
Due to the propensity of relapse and resistance with prolonged androgen deprivation therapy (ADT), there is a growing interest in developing non-hormonal therapeutic approaches as alternative treatment modalities for hormone refractory prostate cancer (HRPC). Although the standard treatment for HRPC consists of a combination of ADT with taxanes and anthracyclines, the clinical use of chemotherapeutics is limited by systemic toxicity stemming from nondiscriminatory drug exposure to normal tissues. In order to improve the tumor selectivity of chemotherapeutics, various targeted prodrug approaches have been explored. Antibody-directed enzyme prodrug therapy (ADEPT) and gene-directed enzyme prodrug therapy (GDEPT) strategies leverage tumor-specific antigens and transcription factors for the specific delivery of cytotoxic anticancer agents using various prodrug-activating enzymes. In prostate cancer, overexpression of tumor-specific proteases such as prostate-specific antigen (PSA) and prostate-specific membrane antigen (PSMA) is being exploited for selective activation of anticancer prodrugs designed to be activated through proteolysis by these prostate cancer-specific enzymes. PSMA- and PSA-activated prodrugs typically comprise an engineered high-specificity protease peptide substrate coupled to a potent cytotoxic agent via a linker for rapid release of cytotoxic species in the vicinity of prostate cancer cells following proteolytic cleavage. Over the past two decades, various such prodrugs have been developed and they were effective at inhibiting prostate tumor growth in rodent models; several of these prodrug approaches have been advanced to clinical trials and may be developed into effective therapies for HRPC.
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Affiliation(s)
- Herve Aloysius
- Department of Medicinal Chemistry, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, NJ, 08854
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26
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Christensen CL, Zandi R, Gjetting T, Cramer F, Poulsen HS. Specifically targeted gene therapy for small-cell lung cancer. Expert Rev Anticancer Ther 2014; 9:437-52. [DOI: 10.1586/era.09.10] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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Evaluating aziridinyl nitrobenzamide compounds as leishmanicidal prodrugs. Antimicrob Agents Chemother 2013; 58:370-7. [PMID: 24165190 DOI: 10.1128/aac.01459-13] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Many of the nitroaromatic agents used in medicine function as prodrugs and must undergo activation before exerting their toxic effects. In most cases, this is catalyzed by flavin mononucleotide (FMN)-dependent type I nitroreductases (NTRs), a class of enzyme absent from higher eukaryotes but expressed by bacteria and several eukaryotic microbes, including trypanosomes and Leishmania. Here, we utilize this difference to evaluate whether members of a library of aziridinyl nitrobenzamides have activity against Leishmania major. Biochemical screens using purified L. major NTR (LmNTR) revealed that compounds containing an aziridinyl-2,4-dinitrobenzyl core were effective substrates for the enzyme and showed that the 4-nitro group was important for this activity. To facilitate drug screening against intracellular amastigote parasites, we generated leishmanial cells that expressed the luciferase reporter gene and optimized a mammalian infection model in a 96-well plate format. A subset of aziridinyl-2,4-dinitrobenzyl compounds possessing a 5-amide substituent displayed significant growth-inhibitory properties against the parasite, with the most potent agents generating 50% inhibitory concentrations of <100 nM for the intracellular form. This antimicrobial activity was shown to be LmNTR specific since L. major NTR(+/-) heterozygote parasites were slightly resistance to most aziridinyl dinitrobenzyl agents tested. When the most potent leishmanicidal agents were screened against the mammalian cells in which the amastigote parasites were propagated, no growth-inhibitory effect was observed at concentrations of up to 100 μM. We conclude that the aziridinyl nitrobenzamides represent a new lead structure that may have the potential to treat leishmanial infections.
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Gui R, Li D, Qi G, Suhad A, Nie X. Inhibition of Grb2-mediated activation of MAPK signal transduction suppresses NOR 1/CB1954-induced cytotoxicity in the HepG2 cell line. Oncol Lett 2012; 4:566-570. [PMID: 23741254 DOI: 10.3892/ol.2012.774] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2012] [Accepted: 06/22/2012] [Indexed: 11/06/2022] Open
Abstract
The nitroreductase oxidored-nitro domain containing protein 1 (NOR1) gene may be involved in the chemical carcinogenesis of hepatic cancer and nasopharyngeal carcinoma (NPC). We have previously demonstrated that NOR1 overexpression is capable of converting the monofunctional alkylating agent 5-(aziridin-1-yl)-2,4-dinitrobenzamide (CB1954) into a toxic form by reducing the 4-nitro group of CB1954. Toxic CB1954 is able to enhance cell killing in the NPC cell line CNE1; however, the underlying mechanisms remain unknown. Using cDNA microarrays and quantitative real-time PCR, we previously discovered that NOR1 increases the expression of growth factor receptor-bound protein 2 (Grb2) mRNA by 4.8-fold in the human hepatocellular carcinoma cell line HepG2. In the present study, we revealed that NOR1 increased Grb2 protein expression by 3-fold in HepG2 cells. Additionally, we demonstrated that NOR1 enhanced CB1954-induced cell killing in HepG2 cells, and cell cytotoxicity was inhibited with the tyrosine kinase inhibitor genistein, or by stable transfection of Grb2 small hairpin RNA (shRNA) pU6+27-shGrb2 to silence the expression of Grb2. Western blot analysis revealed that Grb2 downregulation may reduce the activity of the mitogen-activated protein kinase (MAPK). Inhibiting the activation of MAPK using the methyl ethyl ketone (MEK) inhibtor PD98059 suppressed CB1954-induced cell killing. These results suggested that the NOR1 gene enhances CB1954-mediated cell cytotoxicity through the upregulation of Grb2 expression and the activation of MAPK signal transduction in the HepG2 cell line.
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Affiliation(s)
- Rong Gui
- Clinical Laboratory Centre of the Third Xiangya Hospital, Central South University, Changsha, Hunan 410013, P.R. China
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Çelik A, Yetiş G. An unusually cold active nitroreductase for prodrug activations. Bioorg Med Chem 2012; 20:3540-50. [PMID: 22546205 DOI: 10.1016/j.bmc.2012.04.004] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2011] [Revised: 04/03/2012] [Accepted: 04/04/2012] [Indexed: 11/17/2022]
Abstract
A set of PCR primers based on the genome sequence were used to clone a gene encoding a hypothetical nitroreductases (named as Ssap-NtrB) from uropathogenic staphylococcus, Staphylococcus saprophyticus strain ATCC 15305, an oxygen insensitive flavoenzyme. Activity studies of the translation product revealed that the nitroreductase catalyses two electron reduction of a nitroaromatic drug of nitrofurazone (NFZ), cancer prodrugs of CB1954 and SN23862 at optimum temperature of 20 °C together with retaining its maximum activity considerably at 3 °C. The required electrons for such reduction could be supplied by either NADH or NADPH with a small preference for the latter. The gene was engineered for heterologous expression in Escherichia coli, and conditions were found in which the enzyme was produced in a mostly soluble form. The recombinant enzyme was purified to homogeneity and physical, spectral and catalytical properties were determined. The findings lead us to propose that Ssap-NtrB represents a novel nitro reductase with an unusual cold active property, which has not been described previously for prodrug activating enzymes of nitroreductases.
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Affiliation(s)
- Ayhan Çelik
- Gebze Institute of Technology, Department of Chemistry, 41400 Gebze-Kocaeli, Turkey.
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Hunt MA, Li D, Hay MP, Currie MJ, Robinson BA, Patterson AV, Dachs GU. Characterisation of enzyme prodrug gene therapy combinations in coated spheroids and vascular networks in vitro. J Gene Med 2012; 14:62-74. [DOI: 10.1002/jgm.1635] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Michelle A. Hunt
- Angiogenesis and Cancer Research Group, Department of Pathology; University of Otago; Christchurch; New Zealand
| | - Dan Li
- Auckland Cancer Society Research Centre; University of Auckland; Auckland; New Zealand
| | - Michael P. Hay
- Auckland Cancer Society Research Centre; University of Auckland; Auckland; New Zealand
| | - Margaret J. Currie
- Angiogenesis and Cancer Research Group, Department of Pathology; University of Otago; Christchurch; New Zealand
| | - Bridget A. Robinson
- Angiogenesis and Cancer Research Group, Department of Pathology; University of Otago; Christchurch; New Zealand
| | - Adam V. Patterson
- Auckland Cancer Society Research Centre; University of Auckland; Auckland; New Zealand
| | - Gabi U. Dachs
- Angiogenesis and Cancer Research Group, Department of Pathology; University of Otago; Christchurch; New Zealand
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Dynamic Simulations as a Complement to Experimental Studies of Enzyme Mechanisms. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2012. [DOI: 10.1016/b978-0-12-398312-1.00010-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register]
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Niculescu-Duvaz D, Negoita-Giras G, Niculescu-Duvaz I, Hedley D, Springer CJ. Directed Enzyme Prodrug Therapies. PRODRUGS AND TARGETED DELIVERY 2011. [DOI: 10.1002/9783527633166.ch12] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
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Abstract
The trypanocidal agents nifurtimox and benznidazole both function as prodrugs and must undergo enzyme-mediated activation, a reaction catalyzed by type I nitroreductase (NTR). In the search for new parasitic therapies, we have utilized this finding to investigate whether aziridinyl nitrobenzamide derivatives have activity against bloodstream-form Trypanosoma brucei and Trypanosoma cruzi amastigotes, parasite stages that replicate in the mammalian host. For T. cruzi drug screening, we generated trypanosomes that expressed the luciferase reporter gene and optimized a mammalian infection model in a 96-well plate format. A subset of compounds having a 5-(aziridin-1-yl)-2,4-dinitrobenzyl structure was shown to be metabolized by purified T. brucei NTR and when screened against both parasite life cycle stages displayed significant growth-inhibitory properties: the most potent compounds generated 50% inhibitory concentrations of <1 μM. The trypanocidal activity was shown to be NTR specific, since parasites overexpressing this enzyme were hypersensitive to the aziridinyl dinitrobenzyl agents. We conclude that members of the aziridinyl nitrobenzamide class of nitroheterocycles provide new lead structures that have the potential to treat trypanosomal infections.
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Dachs GU, Hunt MA, Syddall S, Singleton DC, Patterson AV. Bystander or no bystander for gene directed enzyme prodrug therapy. Molecules 2009; 14:4517-45. [PMID: 19924084 PMCID: PMC6255103 DOI: 10.3390/molecules14114517] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2009] [Revised: 11/03/2009] [Accepted: 11/05/2009] [Indexed: 12/12/2022] Open
Abstract
Gene directed enzyme prodrug therapy (GDEPT) of cancer aims to improve the selectivity of chemotherapy by gene transfer, thus enabling target cells to convert nontoxic prodrugs to cytotoxic drugs. A zone of cell kill around gene-modified cells due to transfer of toxic metabolites, known as the bystander effect, leads to tumour regression. Here we discuss the implications of either striving for a strong bystander effect to overcome poor gene transfer, or avoiding the bystander effect to reduce potential systemic effects, with the aid of three successful GDEPT systems. This review concentrates on bystander effects and drug development with regard to these enzyme prodrug combinations, namely herpes simplex virus thymidine kinase (HSV-TK) with ganciclovir (GCV), cytosine deaminase (CD) from bacteria or yeast with 5-fluorocytodine (5-FC), and bacterial nitroreductase (NfsB) with 5-(azaridin-1-yl)-2,4-dinitrobenzamide (CB1954), and their respective derivatives.
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Affiliation(s)
- Gabi U. Dachs
- Angiogenesis and Cancer Research Group, University of Otago, Christchurch, PO Box 4345, Christchurch 8140, New Zealand; E-Mail: (M.A.H.)
| | - Michelle A. Hunt
- Angiogenesis and Cancer Research Group, University of Otago, Christchurch, PO Box 4345, Christchurch 8140, New Zealand; E-Mail: (M.A.H.)
| | - Sophie Syddall
- Auckland Cancer Society Research Centre, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand; E-Mails: (S.S.); (D-C.S.); (A-V.P.)
| | - Dean C. Singleton
- Auckland Cancer Society Research Centre, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand; E-Mails: (S.S.); (D-C.S.); (A-V.P.)
| | - Adam V. Patterson
- Auckland Cancer Society Research Centre, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand; E-Mails: (S.S.); (D-C.S.); (A-V.P.)
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Prosser GA, Copp JN, Syddall SP, Williams EM, Smaill JB, Wilson WR, Patterson AV, Ackerley DF. Discovery and evaluation of Escherichia coli nitroreductases that activate the anti-cancer prodrug CB1954. Biochem Pharmacol 2009; 79:678-87. [PMID: 19852945 DOI: 10.1016/j.bcp.2009.10.008] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2009] [Revised: 10/07/2009] [Accepted: 10/09/2009] [Indexed: 10/20/2022]
Abstract
Gene-directed enzyme prodrug therapy (GDEPT) aims to achieve highly selective tumor-cell killing through the use of tumor-tropic gene delivery vectors coupled with systemic administration of otherwise inert prodrugs. Nitroaromatic prodrugs such as CB1954 hold promise for GDEPT as they are readily reduced to potent DNA alkylating agents by bacterial nitroreductase enzymes (NTRs). Transfection with the nfsB gene from Escherichia coli can increase the sensitivity of tumor cells to CB1954 by greater than 1000-fold. However, poor catalytic efficiency limits the activation of CB1954 by NfsB at clinically relevant doses. A lack of flexible, high-throughput screening technology has hindered efforts to discover superior NTR candidates. Here we demonstrate how the SOS chromotest and complementary screening technologies can be used to evaluate novel enzymes that activate CB1954 and other bioreductive and/or genotoxic prodrugs. We identify the major E. coli NTR, NfsA, as 10-fold more efficient than NfsB in activating CB1954 as purified protein (k(cat)/K(m)) and when over-expressed in an E. coli nfsA(-)/nfsB(-) gene deleted strain. NfsA also confers sensitivity to CB1954 when expressed in HCT-116 human colon carcinoma cells, with similar efficiency to NfsB. In addition, we identify two novel E. coli NTRs, AzoR and NemA, that have not previously been characterized in the context of nitroaromatic prodrug activation.
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Affiliation(s)
- G A Prosser
- School of Biological Sciences, Victoria University of Wellington, Kelburn Parade, Wellington, New Zealand
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Jarrom D, Jaberipour M, Guise CP, Daff S, White SA, Searle PF, Hyde EI. Steady-state and stopped-flow kinetic studies of three Escherichia coli NfsB mutants with enhanced activity for the prodrug CB1954. Biochemistry 2009; 48:7665-72. [PMID: 19580253 DOI: 10.1021/bi900674m] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The enzyme nitroreductase, NfsB, from Escherichia coli has entered clinical trials for cancer gene therapy with the prodrug CB1954 [5-(aziridin-1-yl)-2,4-dinitrobenzamide]. However, CB1954 is a poor substrate for the enzyme. Previously we made several NfsB mutants that show better activity with CB1954 in a cell-killing assay in E. coli. Here we compare the kinetic parameters of wild-type NfsB with CB1954 to those of the most active single, double, and triple mutants isolated to date. For wild-type NfsB the global kinetic parameters for both k(cat) and K(m) for CB1954 are about 20-fold higher than previously estimated; however, the measured specificity constant, k(cat)/K(m) is the same. All of the mutants are more active with CB1954 than the wild-type enzyme, the most active mutant showing about 100-fold improved specificity constant with CB1954 over the wild-type protein with little effect on k(cat). This enhancement in specificity constants for the mutants is not seen with the antibiotic nitrofurazone as substrate, leading to reversed nitroaromatic substrate selectivity for the double and triple mutants. However, similar enhancements in specificity constants are found with the quinone menadione. Stopped-flow kinetic studies suggest that the rate-determining step of the reaction is likely to be the release of products. The most active mutant is also selective for the 4-nitro group of CB1954, rather than the 2-nitro group, giving the more cytotoxic reduction product. The double and triple mutants should be much more effective enzymes for use with CB1954 in prodrug-activation gene therapy.
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Affiliation(s)
- David Jarrom
- School of Biosciences, The University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
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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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Jaberipour M, Vass SO, Guise CP, Grove JI, Knox RJ, Hu L, Hyde EI, Searle PF. Testing double mutants of the enzyme nitroreductase for enhanced cell sensitisation to prodrugs: effects of combining beneficial single mutations. Biochem Pharmacol 2009; 79:102-11. [PMID: 19665450 DOI: 10.1016/j.bcp.2009.07.025] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2009] [Revised: 07/29/2009] [Accepted: 07/31/2009] [Indexed: 10/20/2022]
Abstract
Prodrug activation gene therapy for cancer involves expressing prodrug-activating enzymes in tumour cells, so they can be selectively killed by systemically administered prodrug. For example, Escherichia colinfsB nitroreductase (E.C. 1.6.99.7)(NTR), sensitises cells to the prodrug CB1954 (5-[aziridin-1-yl]-2,4-dinitrobenzamide), which it converts to a potent DNA-crosslinking agent. However, low catalytic efficiency with this non-natural substrate appears to limit the efficacy of this enzyme prodrug combination for eliminating the target cancer cells. To improve this, we aim to engineer NTR for improved prodrug activation. Previously, a number of single amino acid substitutions at six positions around the active site of the enzyme were found to increase activity, resulting in up to approximately 5-fold enhanced cell sensitisation to CB1954. In this study we have made pairwise combinations among some of the best mutants at each of these 6 sites. A total of 53 double mutants were initially screened in E. coli, then the 7 most promising were inserted into an adenovirus vector and compared in SKOV3 human ovarian carcinoma cells for sensitisation to CB1954 and two alternative prodrugs. The most effective mutants, T41L/N71S and T41L/F70A, were 14-17-fold more potent than WT NTR at sensitising the cancer cells to CB1954. The best mutant for activation of the dinitrobenzamide mustard prodrug SN23862 was T41L/F70A (4.8-fold improvement); and S40A/F124M showed 1.7-fold improvement over WT with the nitrobenzylphosphoramide mustard prodrug LH7. In two tumour xenograft models using SKOV3 or human prostate carcinoma PC3, T41L/N71S NTR demonstrated greater CB1954-dependent anti-tumour activity than WT NTR.
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Affiliation(s)
- Mansooreh Jaberipour
- Cancer Research UK Institute for Cancer Studies, University of Birmingham, Birmingham B15 2TT, UK
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Gu Y, Patterson AV, Atwell GJ, Chernikova SB, Brown JM, Thompson LH, Wilson WR. Roles of DNA repair and reductase activity in the cytotoxicity of the hypoxia-activated dinitrobenzamide mustard PR-104A. Mol Cancer Ther 2009; 8:1714-23. [PMID: 19509245 DOI: 10.1158/1535-7163.mct-08-1209] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PR-104 is a dinitrobenzamide mustard currently in clinical trial as a hypoxia-activated prodrug. Its major metabolite, PR-104A, is metabolized to the corresponding hydroxylamine (PR-104H) and amine (PR-104M), resulting in activation of the nitrogen mustard moiety. We characterize DNA damage responsible for cytotoxicity of PR-104A by comparing sensitivity of repair-defective hamster Chinese hamster ovary cell lines with their repair-competent counterparts. PR-104H showed a repair profile similar to the reference DNA cross-linking agents chlorambucil and mitomycin C, with marked hypersensitivity of XPF(-/-), ERCC1(-/-), and Rad51D(-/-) cells but not of XPD(-/-) or DNA-PK(CS)(-/-) cells. This pattern confirmed the expected dependence on the ERCC1-XPF endonuclease, implicated in unhooking DNA interstrand cross-links at blocked replication forks, and homologous recombination repair (HRR) in restarting collapsed forks. However, even under anoxia, the hypersensitivity of XPF(-/-), ERCC1(-/-), and Rad51D(-/-) cells to PR-104A itself was lower than for chlorambucil. To test whether this reflects inefficient PR-104A reduction, a soluble form of human NADPH:cytochrome P450 oxidoreductase was stably expressed in Rad51D(-/-) cells and their HRR-restored counterpart. This expression increased hypoxic metabolism of PR-104A to PR-104H and PR-104M as well as hypoxia-selective cytotoxicity of PR-104A and its dependence on HRR. We conclude that PR-104A cytotoxicity is primarily due to DNA interstrand cross-linking by its reduced metabolites, although under conditions of inefficient PR-104A reduction (low reductase expression or aerobic cells), a second mechanism contributes to cell killing. This study shows that hypoxia, reductase activity, and DNA interstrand cross-link repair proficiency are key variables that interact to determine PR-104A sensitivity.
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Affiliation(s)
- Yongchuan Gu
- Auckland Cancer Society Research Centre, The University of Auckland, Auckland, New Zealand
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40
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Vass SO, Jarrom D, Wilson WR, Hyde EI, Searle PF. E. coli NfsA: an alternative nitroreductase for prodrug activation gene therapy in combination with CB1954. Br J Cancer 2009; 100:1903-11. [PMID: 19455141 PMCID: PMC2690450 DOI: 10.1038/sj.bjc.6605094] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
Prodrug activation gene therapy is a developing approach to cancer treatment, whereby prodrug-activating enzymes are expressed in tumour cells. After administration of a non-toxic prodrug, its conversion to cytotoxic metabolites directly kills tumour cells expressing the activating enzyme, whereas the local spread of activated metabolites can kill nearby cells lacking the enzyme (bystander cell killing). One promising combination that has entered clinical trials uses the nitroreductase NfsB from Escherichia coli to activate the prodrug, CB1954, to a potent bifunctional alkylating agent. NfsA, the major E. coli nitroreductase, has greater activity with nitrofuran antibiotics, but it has not been compared in the past with NfsB for the activation of CB1954. We show superior in vitro kinetics of CB1954 activation by NfsA using the NADPH cofactor, and show that the expression of NfsA in bacterial or human cells results in a 3.5- to 8-fold greater sensitivity to CB1954, relative to NfsB. Although NfsB reduces either the 2-NO2 or 4-NO2 positions of CB1954 in an equimolar ratio, we show that NfsA preferentially reduces the 2-NO2 group, which leads to a greater bystander effect with cells expressing NfsA than with NfsB. NfsA is also more effective than NfsB for cell sensitisation to nitrofurans and to a selection of alternative, dinitrobenzamide mustard (DNBM) prodrugs.
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Affiliation(s)
- S O Vass
- Cancer Research UK Institute for Cancer Studies, University of Birmingham, Birmingham, UK
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Liu SC, Ahn GO, Kioi M, Dorie MJ, Patterson AV, Brown JM. Optimized clostridium-directed enzyme prodrug therapy improves the antitumor activity of the novel DNA cross-linking agent PR-104. Cancer Res 2008; 68:7995-8003. [PMID: 18829557 PMCID: PMC2596930 DOI: 10.1158/0008-5472.can-08-1698] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
We have previously shown that spores of the nonpathogenic clostridial strain C. sporogenes genetically engineered to express the E. coli-derived cytosine deaminase gene are effective in converting systemically injected nontoxic 5-fluorocytosine into the toxic anticancer drug 5-fluorouracil, thereby producing tumor-specific antitumor activity. To improve the expression of E. coli-derived genes with this system, we first replaced the original fdP promoter in the vector with one of two powerful endogenous clostridial promoters: that of the thiolase gene (thlP) and that for the clostridial transcription factor abrB310 (abrBP). These substitutions improved protein expression levels of the prodrug-activating genes by 2- to 3-fold in comparison with fdP-driven expression. However, despite these strong promoters, we found much higher expression of the nitroreductase (NTR) protein in the E. coli host compared with the clostridial host, which we hypothesized could be the result of different codon use between the two organisms. To test this, we constructed new expression vectors with an artificially synthesized NTR gene using optimized clostridial codons (sNTR). Results from both enzymatic assays and Western blots of cell extracts from clostridial transformants harboring plasmid constructs of thlP-sNTR and abrBP-sNTR showed that the expression and activity of the NTR gene product was increased by approximately 20-fold compared with the original construct. In vivo studies with i.v. administered sNTR-expressing C. sporogenes spores in SiHa tumor-bearing mice showed significantly improved antitumor efficacy when combined with either 5-aziridinyl-2,4-dinitrobenzamide (CB1954) or the novel dinitrobenzamide mustard prodrug, PR-104.
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Affiliation(s)
- Shie-Chau Liu
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California, USA
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E. coli nitroreductase/CB1954 gene-directed enzyme prodrug therapy: role of arylamine N-acetlytransferase 2. Cancer Gene Ther 2008; 15:758-64. [PMID: 18600257 DOI: 10.1038/cgt.2008.47] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Gene-directed enzyme prodrug therapy is a promising approach to the local management of cancer and a number of gene prodrug combinations have entered clinical trials. The antitumor activity of Escherichia coli nitroreductase (NTR) in combination with the prodrug CB1954 relies on the reduction of the nitro groups to reactive N-hydroxylamine intermediates that are toxic in proliferating and nonproliferating cells. We examined whether secondary metabolic activation of the N-hydroxylamines by sulfotransferases or acetyltransferases altered cell responsiveness to the drug. We evaluated the coexpression of NTR with the human cytosolic sulfotransferases SULT1A1, 1A2, 1A3, 1E1 and 2A1, or the human arylamine N-acetyltransferases NAT1 and NAT2 on SKOV3 cell survival. Only NAT2 significantly altered the toxicity of CB1954, decreasing the IC(50) 16-fold from 0.61 to 0.04 microM. These results suggest that one or more of the N-hydroxyl metabolites are a substrate for O-acetylation by NAT2. We also examined the bystander effect of SKOV3 cells expressing NTR or NTR plus NAT2. Addition of the acetyltransferase resulted in a significant decreased bystander effect (P>0.01), possibly due to a lower concentration of reactive metabolites in the culture medium. These results suggest that a combination of bacterial NTR and NAT2 may provide a greater clinical response at therapeutic concentrations of CB1954 provided the reduction in bystander effect is not clinically significant. Moreover, endogenous NAT2, which is localized predominantly in the liver and gut, may be involved in the dose-limiting hepatic toxicity and gastrointestinal side effects seen in patients treated with the higher doses of CB1954.
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Chandor A, Dijols S, Ramassamy B, Frapart Y, Mansuy D, Stuehr D, Helsby N, Boucher JL. Metabolic activation of the antitumor drug 5-(Aziridin-1-yl)-2,4-dinitrobenzamide (CB1954) by NO synthases. Chem Res Toxicol 2008; 21:836-43. [PMID: 18370414 DOI: 10.1021/tx7004234] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Nitric oxide synthases (NOSs) are flavohemeproteins that catalyze the oxidation of L-arginine to L-citrulline with formation of the signaling molecule nitric oxide (NO). In addition to their fundamental role in NO biosynthesis, NOSs are also involved in the formation of reactive oxygen and nitrogen species (RONS) and in the interactions with some drugs. 5-(Aziridin-1-yl)-2,4-dinitrobenzamide (CB1954) is a dinitroaromatic compound tested as an antitumor prodrug that requires reduction to the 2- and 4-hydroxylamines to be cytotoxic. Here, we studied the interaction of neuronal, inducible, and endothelial NOSs with CB1954. Our results showed that the three purified recombinant NOSs selectively reduced the 4-nitro group of CB1954 to the corresponding 4-hydroxylamine with minimal 2-nitroreduction. Little further two-electron reduction of the hydroxylamines to the corresponding 2- and 4-amines was observed. The reduction of CB1954 catalyzed by the neuronal NOS (nNOS) was inhibited by O 2 and a flavin/NADPH binding inhibitor, diphenyliodonium (DPI), but insensitive to the addition of the heme ligands imidazole and carbon monoxide and of l-arginine analogues. This reduction proceeded with intermediate formation of a nitro-anion free radical observed by EPR. Involvement of the reductase domain of nNOS in the reduction of CB1954 was confirmed by the ability of the isolated reductase domain of nNOS to catalyze the reaction and by the stimulating effect of Ca (2+)/calmodulin on the accumulation of 4- and 2-hydroxylamines. The recombinant inducible and endothelial NOS isoforms reduced CB1954 with lower activity but higher selectivity for the cytotoxic 4-hydroxylamine compared with nNOS. Finally, CB1954 did not modify the formation of l-citrulline and RONS catalyzed by nNOS. Our results show that all three NOS isoforms are involved in the nitroreduction of CB1954, with predominant formation of the cytotoxic 4-hydroxylamine derivative. This nitroreduction could be of interest for the selective activation of prodrugs by NOSs overexpressed in tumor cells.
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Affiliation(s)
- Alexia Chandor
- Laboratoire de Chimie et Biochimie Pharmacologiques et Toxicologiques, Université R. Descartes, UMR 8601 CNRS, 45 rue des Saints-Pères, 75270 Paris cedex 06, France
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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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Smith SJ, Kotecha S, Towers N, Mohun TJ. Targeted cell-ablation in Xenopus embryos using the conditional, toxic viral protein M2(H37A). Dev Dyn 2007; 236:2159-71. [PMID: 17615576 DOI: 10.1002/dvdy.21233] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Harnessing toxic proteins to destroy selective cells in an embryo is an attractive method for exploring details of cell fate and cell-cell interdependency. However, no existing "suicide gene" system has proved suitable for aquatic vertebrates. We use the M2(H37A) toxic ion channel of the influenza-A virus to induce cell-ablations in Xenopus laevis. M2(H37A) RNA injected into blastomeres of early stage embryos causes death of their progeny by late-blastula stages. Moreover, M2(H37A) toxicity can be controlled using the M2 inhibitor rimantadine. We have tested the ablation system using transgenesis to target M2(H37A) expression to selected cells in the embryo. Using the myocardial MLC2 promoter, M2(H37A)-mediated cell death causes dramatic loss of cardiac structure and function by stage 39. With the LURP1 promoter, we induce cell-ablations of macrophages. These experiments demonstrate the effectiveness of M2(H37A)-ablation in Xenopus and its utility in monitoring the progression of developmental abnormalities during targeted cell death experiments.
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Affiliation(s)
- Stuart J Smith
- Division of Developmental Biology, National Institute for Medical Research, The Ridgeway, Mill Hill, London, United Kingdom
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Helsby NA, Goldthorpe MA, Tang MHY, Atwell GJ, Smith EM, Wilson WR, Tingle MD. Influence of mustard group structure on pathways of in vitro metabolism of anticancer N-(2-hydroxyethyl)-3,5-dinitrobenzamide 2-mustard prodrugs. Drug Metab Dispos 2007; 36:353-60. [PMID: 17998296 DOI: 10.1124/dmd.107.018739] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The dinitrobenzamide mustards are a class of bioreductive nitro-aromatic anticancer prodrugs, of which a phosphorylated analog (PR-104) is currently in clinical development. They are bioactivated by tumor reductases to form DNA cross-linking cytotoxins. However, their biotransformation in normal tissues has not been examined. Here we report the aerobic in vitro metabolism of three N-(2 hydroxyethyl)-3,5-dinitrobenzamide 2-mustards and the corresponding nonmustard analog in human, mouse, rat, and dog hepatic S9 preparations. These compounds have a range of mustard structures (-N(CH(2)CH(2)X)(2) where X = H, Cl, Br, or OSO(2)Me). Four metabolic routes were identified: reduction of either nitro group, N-dealkylation of the mustard, plus O-acetylation, and O-glucuronidation of the hydroxyethyl side chain. Reduction of the nitro group ortho to the mustard resulted in intramolecular alkylation and is considered to be an inactivation pathway, whereas reduction of the nitro group para to the mustard generated potential DNA cross-linking cytotoxins. N-Dealkylation inactivated the mustard moiety but may result in the formation of toxic acetaldehyde derivatives. Increasing the size of the nitrogen mustard leaving group abrogated the ortho-nitroreduction and N-dealkylation routes and thereby improved overall metabolic stability but had little effect on aerobic para-nitroreduction. All four compounds underwent O-glucuronidation of the hydroxyethyl side chain and further studies to elucidate the relative importance of this pathway in vivo are in progress.
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Affiliation(s)
- Nuala A Helsby
- Department of Molecular Medicine and Pathology, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand.
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Singleton DC, Li D, Bai SY, Syddall SP, Smaill JB, Shen Y, Denny WA, Wilson WR, Patterson AV. The nitroreductase prodrug SN 28343 enhances the potency of systemically administered armed oncolytic adenovirus ONYX-411NTR. Cancer Gene Ther 2007; 14:953-67. [DOI: 10.1038/sj.cgt.7701088] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Tang MHY, Helsby NA, Goldthorpe MA, Thompson KM, Al-Ali S, Tingle MD. Hepatic nitroreduction, toxicity and toxicokinetics of the anti-tumour prodrug CB 1954 in mouse and rat. Toxicology 2007; 240:70-85. [PMID: 17804142 DOI: 10.1016/j.tox.2007.07.018] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2007] [Revised: 07/19/2007] [Accepted: 07/19/2007] [Indexed: 11/22/2022]
Abstract
5-(Aziridin-1-yl)-2,4-dinitrobenzamide (CB 1954), a promising anti-tumour compound, is associated with clinical hepatotoxicity. We have previously demonstrated that human liver preparations are capable of endogenous 2- and 4-nitroreduction of CB 1954 to generate highly potent cytotoxins. The present study initially examined the in vitro metabolism of CB 1954 in S9 preparations of several non-clinical species and strains. The CD-1 nu/nu mouse and Sprague-Dawley rat were subsequently chosen for further assessment of in vivo metabolism and hepatotoxicity of CB 1954, as well as the mechanisms that may be involved. Animals were administered the maximum tolerated dose (MTD). At 562 micromol/kg, the mouse exhibited transaminase elevation and centrilobular hepatocyte injury. Moreover, thiol adducts as well as hepatic glutathione depletion paralleled temporally by maximal nitroreduction were observed. The rat had a much lower MTD of 40 micromol/kg and showed signs of gastro-intestinal disturbances. In contrast to mouse, peri-portal damage and biliary changes were observed in rat without any alterations in plasma biomarkers or hepatic glutathione levels. Immunohistochemical analysis did not reveal any correlation between the location of injury and expression of cytochrome P450 reductase and NAD(P)H quinone oxidoreductase 1, two enzymes implicated in the bioactivation of this drug. In conclusion, the present study showed that following administration of CB 1954 at the respective MTDs, hepatotoxicity was observed in both mouse and rat. However, the degree of sensitivity to the drug and the mechanisms of toxicity involved appear to be widely different between CD-1 nu/nu mice and Sprague-Dawley rats.
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Affiliation(s)
- Magdalene Huen Yin Tang
- Department of Pharmacology and Clinical Pharmacology, University of Auckland, Private Bag 92019, Auckland, New Zealand.
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Hicks KO, Myint H, Patterson AV, Pruijn FB, Siim BG, Patel K, Wilson WR. Oxygen Dependence and Extravascular Transport of Hypoxia-Activated Prodrugs: Comparison of the Dinitrobenzamide Mustard PR-104A and Tirapazamine. Int J Radiat Oncol Biol Phys 2007; 69:560-71. [PMID: 17869669 DOI: 10.1016/j.ijrobp.2007.05.049] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2007] [Revised: 05/28/2007] [Accepted: 05/29/2007] [Indexed: 10/22/2022]
Abstract
PURPOSE To compare oxygen dependence and tissue transport properties of a new hypoxia-activated prodrug, PR-104A, with tirapazamine, and to evaluate the implications for antitumor activity when combined with radiotherapy. METHODS AND MATERIALS Oxygen dependence of cytotoxicity was measured by clonogenic assay in SiHa cell suspensions. Tissue transport parameters were determined using SiHa multicellular layers. Spatially resolved pharmacokinetic (PK) and pharmacodynamic (PD) models were developed to predict cell killing in SiHa tumors and tested by clonogenic assay 18 h after treatment with the corresponding phosphate ester, PR-104. RESULTS The K-value (oxygen concentration to halve cytotoxic potency) of PR-104A was 0.126 +/- 0.021 microM (10-fold lower than tirapazamine at 1.30 +/- 0.28 microM). The diffusion coefficient of PR-104A in multicellular layers (4.42 +/- 0.15 x 10(-7) cm2 s(-1)) was lower than that of tirapazamine (1.30 +/- 0.05 x 10(-6) cm2 s(-1)) but PK modeling predicted better penetration to hypoxic cells in tumors because of its slower metabolism. The tirapazamine PK/PD model successfully predicted the measured activity in combination with single-dose radiation against SiHa tumors, and the PR-104A model underpredicted the activity, which was greater for PR-104 than for tirapazamine (at equivalent host toxicity) both with radiation and as a single agent. CONCLUSION PR-104/PR-104A has different PK/PD properties from tirapazamine and superior activity with single-dose radiotherapy against SiHa xenografts. We have inferred that PR-104A is better able to kill cells at intermediate partial pressure of oxygen in tumors than implied by the PK/PD model, most likely because of a bystander effect resulting from diffusion of its activated metabolites from severely hypoxic zones.
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Affiliation(s)
- Kevin O Hicks
- Auckland Cancer Society Research Centre, University of Auckland School of Medical Sciences, Auckland, New Zealand.
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Patterson AV, Ferry DM, Edmunds SJ, Gu Y, Singleton RS, Patel K, Pullen SM, Hicks KO, Syddall SP, Atwell GJ, Yang S, Denny WA, Wilson WR. Mechanism of action and preclinical antitumor activity of the novel hypoxia-activated DNA cross-linking agent PR-104. Clin Cancer Res 2007; 13:3922-32. [PMID: 17606726 DOI: 10.1158/1078-0432.ccr-07-0478] [Citation(s) in RCA: 181] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PURPOSE Hypoxia is a characteristic of solid tumors and a potentially important therapeutic target. Here, we characterize the mechanism of action and preclinical antitumor activity of a novel hypoxia-activated prodrug, the 3,5-dinitrobenzamide nitrogen mustard PR-104, which has recently entered clinical trials. EXPERIMENTAL DESIGN Cytotoxicity in vitro was evaluated using 10 human tumor cell lines. SiHa cells were used to characterize metabolism under hypoxia, by liquid chromatography-mass spectrometry, and DNA damage by comet assay and gammaH2AX formation. Antitumor activity was evaluated in multiple xenograft models (PR-104 +/- radiation or chemotherapy) by clonogenic assay 18 h after treatment or by tumor growth delay. RESULTS The phosphate ester "pre-prodrug" PR-104 was well tolerated in mice and converted rapidly to the corresponding prodrug PR-104A. The cytotoxicity of PR-104A was increased 10- to 100-fold by hypoxia in vitro. Reduction to the major intracellular metabolite, hydroxylamine PR-104H, resulted in DNA cross-linking selectively under hypoxia. Reaction of PR-104H with chloride ion gave lipophilic cytotoxic metabolites potentially able to provide bystander effects. In tumor excision assays, PR-104 provided greater killing of hypoxic (radioresistant) and aerobic cells in xenografts (HT29, SiHa, and H460) than tirapazamine or conventional mustards at equivalent host toxicity. PR-104 showed single-agent activity in six of eight xenograft models and greater than additive antitumor activity in combination with drugs likely to spare hypoxic cells (gemcitabine with Panc-01 pancreatic tumors and docetaxel with 22RV1 prostate tumors). CONCLUSIONS PR-104 is a novel hypoxia-activated DNA cross-linking agent with marked activity against human tumor xenografts, both as monotherapy and combined with radiotherapy and chemotherapy.
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Affiliation(s)
- Adam V Patterson
- Auckland Cancer Society Research Centre, School of Medical Sciences, The University of Auckland, Auckland, New Zealand
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