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Sharrock AV, Mumm JS, Williams EM, Čėnas N, Smaill JB, Patterson AV, Ackerley DF, Bagdžiūnas G, Arcus VL. Structural Evaluation of a Nitroreductase Engineered for Improved Activation of the 5-Nitroimidazole PET Probe SN33623. Int J Mol Sci 2024; 25:6593. [PMID: 38928299 PMCID: PMC11203732 DOI: 10.3390/ijms25126593] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2024] [Revised: 06/12/2024] [Accepted: 06/13/2024] [Indexed: 06/28/2024] Open
Abstract
Bacterial nitroreductase enzymes capable of activating imaging probes and prodrugs are valuable tools for gene-directed enzyme prodrug therapies and targeted cell ablation models. We recently engineered a nitroreductase (E. coli NfsB F70A/F108Y) for the substantially enhanced reduction of the 5-nitroimidazole PET-capable probe, SN33623, which permits the theranostic imaging of vectors labeled with oxygen-insensitive bacterial nitroreductases. This mutant enzyme also shows improved activation of the DNA-alkylation prodrugs CB1954 and metronidazole. To elucidate the mechanism behind these enhancements, we resolved the crystal structure of the mutant enzyme to 1.98 Å and compared it to the wild-type enzyme. Structural analysis revealed an expanded substrate access channel and new hydrogen bonding interactions. Additionally, computational modeling of SN33623, CB1954, and metronidazole binding in the active sites of both the mutant and wild-type enzymes revealed key differences in substrate orientations and interactions, with improvements in activity being mirrored by reduced distances between the N5-H of isoalloxazine and the substrate nitro group oxygen in the mutant models. These findings deepen our understanding of nitroreductase substrate specificity and catalytic mechanisms and have potential implications for developing more effective theranostic imaging strategies in cancer treatment.
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Affiliation(s)
- Abigail V. Sharrock
- School of Biological Sciences, Victoria University of Wellington, Wellington 6012, New Zealand; (A.V.S.)
| | - Jeff S. Mumm
- Wilmer Eye Institute, Johns Hopkins University, Baltimore, MD 21287, USA;
| | - Elsie M. Williams
- School of Biological Sciences, Victoria University of Wellington, Wellington 6012, New Zealand; (A.V.S.)
| | - Narimantas Čėnas
- Institute of Biochemistry, Life Sciences Center at Vilnius University, Saulėtekio Av. 7, LT-10257 Vilnius, Lithuania;
| | - Jeff B. Smaill
- Auckland Cancer Society Research Centre, School of Medical Sciences, The University of Auckland, Auckland 1142, New Zealand; (J.B.S.); (A.V.P.)
| | - Adam V. Patterson
- Auckland Cancer Society Research Centre, School of Medical Sciences, The University of Auckland, Auckland 1142, New Zealand; (J.B.S.); (A.V.P.)
| | - David F. Ackerley
- School of Biological Sciences, Victoria University of Wellington, Wellington 6012, New Zealand; (A.V.S.)
| | - Gintautas Bagdžiūnas
- Institute of Biochemistry, Life Sciences Center at Vilnius University, Saulėtekio Av. 7, LT-10257 Vilnius, Lithuania;
| | - Vickery L. Arcus
- Te Aka Mātuatua School of Science, University of Waikato, Hamilton 3240, New Zealand;
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Russo S, Luján AP, Fraaije MW, Poelarends GJ. Synthesis of Pharmaceutically Relevant Arylamines Enabled by a Nitroreductase from Bacillus tequilensis. Chembiochem 2024; 25:e202300846. [PMID: 38502784 DOI: 10.1002/cbic.202300846] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2024] [Revised: 03/18/2024] [Accepted: 03/19/2024] [Indexed: 03/21/2024]
Abstract
Arylamines are essential building blocks for the manufacture of valuable pharmaceuticals, pigments and dyes. However, their current industrial production involves the use of chemocatalytic procedures with a significant environmental impact. As a result, flavin-dependent nitroreductases (NRs) have received increasing attention as sustainable catalysts for more ecofriendly synthesis of arylamines. In this study, we assessed a novel NR from Bacillus tequilensis, named BtNR, for the synthesis of pharmaceutically relevant arylamines, including valuable synthons used in the manufacture of blockbuster drugs such as vismodegib, sonidegib, linezolid and sildenafil. After optimizing the enzymatic reaction conditions, high conversion of nitroaromatics to arylamines (up to 97 %) and good product yields (up to 56 %) were achieved. Our results indicate that BtNR has a broad substrate scope, including bulky nitro benzenes, nitro pyrazoles and nitro pyridines. Hence, BtNR is an interesting biocatalyst for the synthesis of pharmaceutically relevant amine-functionalized aromatics, providing an attractive alternative to traditional chemical synthesis methodologies.
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Affiliation(s)
- Sara Russo
- Department of Chemical and Pharmaceutical Biology, Groningen Research Institute of Pharmacy, University of Groningen, Antonius Deusinglaan 1, 9713 AV, Groningen, The Netherlands
- Molecular Enzymology Group, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 4, 9747 AG, Groningen, The Netherlands
| | - Alejandro Prats Luján
- Department of Chemical and Pharmaceutical Biology, Groningen Research Institute of Pharmacy, University of Groningen, Antonius Deusinglaan 1, 9713 AV, Groningen, The Netherlands
| | - Marco W Fraaije
- Molecular Enzymology Group, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 4, 9747 AG, Groningen, The Netherlands
| | - Gerrit J Poelarends
- Department of Chemical and Pharmaceutical Biology, Groningen Research Institute of Pharmacy, University of Groningen, Antonius Deusinglaan 1, 9713 AV, Groningen, The Netherlands
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3
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Day MA, Christofferson AJ, Anderson JLR, Vass SO, Evans A, Searle PF, White SA, Hyde EI. Structure and Dynamics of Three Escherichia coli NfsB Nitro-Reductase Mutants Selected for Enhanced Activity with the Cancer Prodrug CB1954. Int J Mol Sci 2023; 24:ijms24065987. [PMID: 36983061 PMCID: PMC10051150 DOI: 10.3390/ijms24065987] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Revised: 02/16/2023] [Accepted: 02/27/2023] [Indexed: 03/30/2023] Open
Abstract
Escherichia coli NfsB has been studied extensively for its potential for cancer gene therapy by reducing the prodrug CB1954 to a cytotoxic derivative. We have previously made several mutants with enhanced activity for the prodrug and characterised their activity in vitro and in vivo. Here, we determine the X-ray structure of our most active triple and double mutants to date, T41Q/N71S/F124T and T41L/N71S. The two mutant proteins have lower redox potentials than wild-type NfsB, and the mutations have lowered activity with NADH so that, in contrast to the wild-type enzyme, the reduction of the enzyme by NADH, rather than the reaction with CB1954, has a slower maximum rate. The structure of the triple mutant shows the interaction between Q41 and T124, explaining the synergy between these two mutations. Based on these structures, we selected mutants with even higher activity. The most active one contains T41Q/N71S/F124T/M127V, in which the additional M127V mutation enlarges a small channel to the active site. Molecular dynamics simulations show that the mutations or reduction of the FMN cofactors of the protein has little effect on its dynamics and that the largest backbone fluctuations occur at residues that flank the active site, contributing towards its broad substrate range.
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Affiliation(s)
- Martin A Day
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
- Institute for Cancer Studies, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | | | | | - Simon O Vass
- Institute for Cancer Studies, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - Adam Evans
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - Peter F Searle
- Institute for Cancer Studies, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - Scott A White
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - Eva I Hyde
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
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4
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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: 1] [Impact Index Per Article: 0.3] [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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5
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Hyde EI, Chau AKW, Smith LJ. Backbone assignment of E. coli NfsB and the effects of addition of the cofactor analogue nicotinic acid. BIOMOLECULAR NMR ASSIGNMENTS 2021; 15:143-151. [PMID: 33423170 PMCID: PMC7974150 DOI: 10.1007/s12104-020-09997-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/26/2020] [Accepted: 12/11/2020] [Indexed: 06/12/2023]
Abstract
E. coli nitroreductase NfsB (also called NfnB) has been studied extensively, largely due to its potential for cancer gene therapy. A homodimeric flavoprotein of 216 residues, it catalyses the reduction of nitroaromatics to cytotoxic hydroxylamines by NADH and NADPH and also the reduction of quinones to hydroxyquinones. Its role in vivo is not known but it is postulated to be involved in reducing oxidative stress. The crystal structures of the wild type protein and several homologues have been determined in the absence and presence of ligands, including nicotinate as a mimic of the headpiece of the nicotinamide cofactors. There is little effect on the overall structure of the protein on binding ligands, but, from the B factors, there appears to be a decrease in mobility of 2 helices near the active site. As a first step towards examining the dynamics of the protein in solution with and without ligand, we have assigned the backbone 13C, 15N, and 1HN resonances of NfsB and examined the effect of the binding of nicotinate on the amide 15N, and 1HN shifts.
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Affiliation(s)
- Eva I Hyde
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK.
| | - Alex Ka-Wing Chau
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
- Legislative Council Complex, Central, Hong Kong
| | - Lorna J Smith
- Department of Chemistry, University of Oxford, Oxford, OX1 3QR, UK.
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6
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Rice AM, Long Y, King SB. Nitroaromatic Antibiotics as Nitrogen Oxide Sources. Biomolecules 2021; 11:267. [PMID: 33673069 PMCID: PMC7918234 DOI: 10.3390/biom11020267] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Revised: 02/09/2021] [Accepted: 02/10/2021] [Indexed: 12/21/2022] Open
Abstract
Nitroaromatic antibiotics show activity against anaerobic bacteria and parasites, finding use in the treatment of Heliobacter pylori infections, tuberculosis, trichomoniasis, human African trypanosomiasis, Chagas disease and leishmaniasis. Despite this activity and a clear need for the development of new treatments for these conditions, the associated toxicity and lack of clear mechanisms of action have limited their therapeutic development. Nitroaromatic antibiotics require reductive bioactivation for activity and this reductive metabolism can convert the nitro group to nitric oxide (NO) or a related reactive nitrogen species (RNS). As nitric oxide plays important roles in the defensive immune response to bacterial infection through both signaling and redox-mediated pathways, defining controlled NO generation pathways from these antibiotics would allow the design of new therapeutics. This review focuses on the release of nitrogen oxide species from various nitroaromatic antibiotics to portend the increased ability for these compounds to positively impact infectious disease treatment.
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Affiliation(s)
| | | | - S. Bruce King
- Department of Chemistry and Biochemistry, Wake Forest University, Winston-Salem, NC 27101, USA; (A.M.R.); (Y.L.)
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7
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Han H, Zheng Y, Zhou T, Liu P, Li X. Cu(II) nonspecifically binding chromate reductase NfoR promotes Cr(VI) reduction. Environ Microbiol 2020; 23:415-430. [PMID: 33201569 DOI: 10.1111/1462-2920.15329] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Revised: 10/30/2020] [Accepted: 11/15/2020] [Indexed: 11/26/2022]
Abstract
Cu(II)-enhanced microbial Cr(VI) reduction is common in the environment, yet its mechanism is unknown. The specific activity of chromate reductase, NfoR, from Staphylococcus aureus sp. LZ-01 was augmented 1.5-fold by Cu(II). Isothermal titration calorimetry and spectral data show that Cu(II) binds to NfoR nonspecifically. Further, Cu(II) stimulates the nitrobenzene reduction of NfoR, indicating that Cu(II) promotes electron transfer. The crystal structure of NfoR in complex with CuSO4 (1.46 Å) was determined. The overall structure of NfoR-Cu(II) complex is a dimer that covalently binds with FMN and Cu(II)-binding pocket is located at the interface of the NfoR dimer. Structural superposition revealed that NfoR resembles the structure of class II chromate reductase. Site-directed mutagenesis revealed that Leu46 and Phe123 were involved in NADH binding, whereas Trp70 and Ser45 were the key residues for nitrobenzene binding. Furthermore, His100 and Asp171 were preferential affinity sites for Cu(II) and that Cys163 is an active site for FMN binding. Attenuation reductase activity in C163S can be partially restored to 54% wild type by increasing Cu(II) concentration. Partial restoration indicates dual-channel electron transfer of NfoR via Cu(II) and FMN. We propose a catalytic mechanism for Cu(II)-enhanced NfoR activity in which Cu(I) is formed transiently. Together, the current results provide an insight on Cu (II)-induced enhancement and benefit of Cr(VI) bioremediation.
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Affiliation(s)
- Huawen Han
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Science, Lanzhou University, Lanzhou, China
| | - Yuanzhang Zheng
- Department of Chemistry and Biochemistry, Loyola University Chicago, Chicago, IL, USA
| | - Tuoyu Zhou
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Science, Lanzhou University, Lanzhou, China
| | - Pu Liu
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Science, Lanzhou University, Lanzhou, China
| | - Xiangkai Li
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Science, Lanzhou University, Lanzhou, China
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8
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Boddu RS, Perumal O, K D. Microbial nitroreductases: A versatile tool for biomedical and environmental applications. Biotechnol Appl Biochem 2020; 68:1518-1530. [PMID: 33156534 DOI: 10.1002/bab.2073] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2020] [Accepted: 11/02/2020] [Indexed: 12/24/2022]
Abstract
Nitroreductases, enzymes found mostly in bacteria and also in few eukaryotes, use nicotinamide adenine dinucleotide (NADH) or nicotinamide adenine dinucleotide phosphate (NADPH) as a cofactor for their activity and metabolize an enormous list of a diverse nitro group-containing compounds. Nitroreductases that are capable of metabolizing nitroaromatic and nitro heterocyclic compounds have drawn great attention in recent years owing to their biotechnological, biomedical, environmental, and human impact. These enzymes attracted medicinal chemists and pharmacologists because of their prodrug selectivity for activation/reduction of nitro compounds that wipe out pathogens/cancer cells, leaving the host/normal cells unharmed. It is applied in diverse fields of study like prodrug activation in treating cancer and leishmaniasis, designing fluorescent probes for hypoxia detection, cell imaging, ablation of specific cell types, biodegradation of nitro-pollutants, and interpretation of mutagenicity of nitro compounds. Keeping in view the immense prospects of these enzymes and a large number of research contributions in this area, the present review encompasses the enzymatic reaction mechanism, their role in antibiotic resistance, hypoxia sensing, cell imaging, cancer therapy, reduction of recalcitrant nitro chemicals, enzyme variants, and their specificity to substrates, reaction products, and their applications.
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Affiliation(s)
- Ramya Sree Boddu
- Department of Biotechnology, National Institute of Technology, Warangal, India
| | - Onkara Perumal
- Department of Biotechnology, National Institute of Technology, Warangal, India
| | - Divakar K
- Department of Biotechnology, Sri Venkateswara College of Engineering, Sriperumbudur, India
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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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Thiel Z, Nguyen J, Rivera‐Fuentes P. Genetically Encoded Activators of Small Molecules for Imaging and Drug Delivery. Angew Chem Int Ed Engl 2020; 59:7669-7677. [PMID: 31898373 PMCID: PMC7318188 DOI: 10.1002/anie.201915521] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Indexed: 12/30/2022]
Abstract
Chemical biologists have developed many tools based on genetically encoded macromolecules and small, synthetic compounds. The two different approaches are extremely useful, but they have inherent limitations. In this Minireview, we highlight examples of strategies that combine both concepts to tackle challenging problems in chemical biology. We discuss applications in imaging, with a focus on super-resolved techniques, and in probe and drug delivery. We propose future directions in this field, hoping to inspire chemical biologists to develop new combinations of synthetic and genetically encoded probes.
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Affiliation(s)
- Zacharias Thiel
- Institute of Chemical Sciences and EngineeringEPF LausanneCH C2 425, Station 61015LausanneSwitzerland
- Laboratory of Organic ChemistryETH ZurichVladimir-Prelog-Weg 38093ZurichSwitzerland
| | - Jade Nguyen
- Institute of Chemical Sciences and EngineeringEPF LausanneCH C2 425, Station 61015LausanneSwitzerland
- Laboratory of Organic ChemistryETH ZurichVladimir-Prelog-Weg 38093ZurichSwitzerland
| | - Pablo Rivera‐Fuentes
- Institute of Chemical Sciences and EngineeringEPF LausanneCH C2 425, Station 61015LausanneSwitzerland
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11
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Thiel Z, Nguyen J, Rivera‐Fuentes P. Genetically Encoded Activators of Small Molecules for Imaging and Drug Delivery. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.201915521] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Zacharias Thiel
- Institute of Chemical Sciences and Engineering EPF Lausanne CH C2 425, Station 6 1015 Lausanne Switzerland
- Laboratory of Organic Chemistry ETH Zurich Vladimir-Prelog-Weg 3 8093 Zurich Switzerland
| | - Jade Nguyen
- Institute of Chemical Sciences and Engineering EPF Lausanne CH C2 425, Station 6 1015 Lausanne Switzerland
- Laboratory of Organic Chemistry ETH Zurich Vladimir-Prelog-Weg 3 8093 Zurich Switzerland
| | - Pablo Rivera‐Fuentes
- Institute of Chemical Sciences and Engineering EPF Lausanne CH C2 425, Station 6 1015 Lausanne Switzerland
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12
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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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13
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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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14
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Abstract
Introduction: Prodrugs have been used to improve the selectivity and efficacy of cancer therapy by targeting unique abnormal markers that are overexpressed by cancer cells and are absent in normal tissues. In this context, different strategies have been exploited and new ones are being developed each year. Areas covered: In this review, an integrated view of the potential use of prodrugs in targeted cancer therapy is provided. Passive and active strategies are discussed in light of the advantages of each one and some successful examples are provided, as well as the clinical status of several prodrugs. Among them, antibody-drug conjugates (ADCs) are the most commonly used. However, several drawbacks, including limited prodrug uptake, poor pharmacokinetics, immunogenicity problems, difficulties in selective targeting and gene expression, and optimized bystander effects limit their clinical applications. Expert opinion: Despite the efforts of different companies and research groups, several drawbacks, such as the lack of relevant in vivo models, complexity of the human metabolism, and economic limitations, have hampered the development of new prodrugs for targeted cancer therapy. As a result, we believe that the combination of prodrugs with cancer nanotechnology and other newly developed approaches, such as aptamer-conjugated nanomaterials, are efficient strategies.
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Affiliation(s)
- Carla Souza
- a Center of Nanotechnology and Tissue Engineering, Department of Chemistry , School of Philosophy, Sciences and Letters of Ribeirão Preto- USP , Ribeirão Preto , Brazil
| | - Diogo Silva Pellosi
- b Department of Chemistry, Laboratory of Hybrid Materials , Federal University of São Paulo - UNIFESP , Diadema , Brazil
| | - Antonio Claudio Tedesco
- a Center of Nanotechnology and Tissue Engineering, Department of Chemistry , School of Philosophy, Sciences and Letters of Ribeirão Preto- USP , Ribeirão Preto , Brazil
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15
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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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16
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Gruber TD, Krishnamurthy C, Grimm JB, Tadross MR, Wysocki LM, Gartner ZJ, Lavis LD. Cell-Specific Chemical Delivery Using a Selective Nitroreductase-Nitroaryl Pair. ACS Chem Biol 2018; 13:2888-2896. [PMID: 30111097 DOI: 10.1021/acschembio.8b00524] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The utility of small molecules to probe or perturb biological systems is limited by the lack of cell-specificity. "Masking" the activity of small molecules using a general chemical modification and "unmasking" it only within target cells overcomes this limitation. To this end, we have developed a selective enzyme-substrate pair consisting of engineered variants of E. coli nitroreductase (NTR) and a 2-nitro- N-methylimidazolyl (NM) masking group. To discover and optimize this NTR-NM system, we synthesized a series of fluorogenic substrates containing different nitroaromatic masking groups, confirmed their stability in cells, and identified the best substrate for NTR. We then engineered the enzyme for improved activity in mammalian cells, ultimately yielding an enzyme variant (enhanced NTR, or eNTR) that possesses up to 100-fold increased activity over wild-type NTR. These improved NTR enzymes combined with the optimal NM masking group enable rapid, selective unmasking of dyes, indicators, and drugs to genetically defined populations of cells.
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Affiliation(s)
- Todd D Gruber
- Janelia Research Campus , Howard Hughes Medical Institute , Ashburn , Virginia 20147 , United States
| | - Chithra Krishnamurthy
- Janelia Research Campus , Howard Hughes Medical Institute , Ashburn , Virginia 20147 , United States
- Department of Pharmaceutical Chemistry , University of California , San Francisco , California 94158 , United States
| | - Jonathan B Grimm
- Janelia Research Campus , Howard Hughes Medical Institute , Ashburn , Virginia 20147 , United States
| | - Michael R Tadross
- Janelia Research Campus , Howard Hughes Medical Institute , Ashburn , Virginia 20147 , United States
| | - Laura M Wysocki
- Janelia Research Campus , Howard Hughes Medical Institute , Ashburn , Virginia 20147 , United States
| | - Zev J Gartner
- Department of Pharmaceutical Chemistry , University of California , San Francisco , California 94158 , United States
| | - Luke D Lavis
- Janelia Research Campus , Howard Hughes Medical Institute , Ashburn , Virginia 20147 , United States
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17
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Miller AF, Park JT, Ferguson KL, Pitsawong W, Bommarius AS. Informing Efforts to Develop Nitroreductase for Amine Production. Molecules 2018; 23:molecules23020211. [PMID: 29364838 PMCID: PMC6017928 DOI: 10.3390/molecules23020211] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2017] [Revised: 01/03/2018] [Accepted: 01/12/2018] [Indexed: 12/19/2022] Open
Abstract
Nitroreductases (NRs) hold promise for converting nitroaromatics to aromatic amines. Nitroaromatic reduction rate increases with Hammett substituent constant for NRs from two different subgroups, confirming substrate identity as a key determinant of reactivity. Amine yields were low, but compounds yielding amines tend to have a large π system and electron withdrawing substituents. Therefore, we also assessed the prospects of varying the enzyme. Several different subgroups of NRs include members able to produce aromatic amines. Comparison of four NR subgroups shows that they provide contrasting substrate binding cavities with distinct constraints on substrate position relative to the flavin. The unique architecture of the NR dimer produces an enormous contact area which we propose provides the stabilization needed to offset the costs of insertion of the active sites between the monomers. Thus, we propose that the functional diversity included in the NR superfamily stems from the chemical versatility of the flavin cofactor in conjunction with a structure that permits tremendous active site variability. These complementary properties make NRs exceptionally promising enzymes for development for biocatalysis in prodrug activation and conversion of nitroaromatics to valuable aromatic amines. We provide a framework for identifying NRs and substrates with the greatest potential to advance.
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Affiliation(s)
- Anne-Frances Miller
- Department of Chemistry, University of Kentucky, Lexington, KY 40506-0055, USA.
| | - Jonathan T Park
- School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA 30332-0100, USA.
| | - Kyle L Ferguson
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA 30332-0100, USA.
| | - Warintra Pitsawong
- Department of Chemistry, University of Kentucky, Lexington, KY 40506-0055, USA.
| | - Andreas S Bommarius
- School of Chemical and Biomolecular Engineering, School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA 30332-0100, USA.
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18
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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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19
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Akiva E, Copp JN, Tokuriki N, Babbitt PC. Evolutionary and molecular foundations of multiple contemporary functions of the nitroreductase superfamily. Proc Natl Acad Sci U S A 2017; 114:E9549-E9558. [PMID: 29078300 PMCID: PMC5692541 DOI: 10.1073/pnas.1706849114] [Citation(s) in RCA: 97] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Insight regarding how diverse enzymatic functions and reactions have evolved from ancestral scaffolds is fundamental to understanding chemical and evolutionary biology, and for the exploitation of enzymes for biotechnology. We undertook an extensive computational analysis using a unique and comprehensive combination of tools that include large-scale phylogenetic reconstruction to determine the sequence, structural, and functional relationships of the functionally diverse flavin mononucleotide-dependent nitroreductase (NTR) superfamily (>24,000 sequences from all domains of life, 54 structures, and >10 enzymatic functions). Our results suggest an evolutionary model in which contemporary subgroups of the superfamily have diverged in a radial manner from a minimal flavin-binding scaffold. We identified the structural design principle for this divergence: Insertions at key positions in the minimal scaffold that, combined with the fixation of key residues, have led to functional specialization. These results will aid future efforts to delineate the emergence of functional diversity in enzyme superfamilies, provide clues for functional inference for superfamily members of unknown function, and facilitate rational redesign of the NTR scaffold.
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Affiliation(s)
- Eyal Akiva
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, CA 94158
| | - Janine N Copp
- Michael Smith Laboratories, University of British Columbia, Vancouver, BC, Canada V6T 1Z4
| | - Nobuhiko Tokuriki
- Michael Smith Laboratories, University of British Columbia, Vancouver, BC, Canada V6T 1Z4;
| | - Patricia C Babbitt
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, CA 94158;
- California Institute for Quantitative Biosciences, University of California, San Francisco, CA 94158
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20
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Zhang X, Li X, You Q, Zhang X. Prodrug strategy for cancer cell-specific targeting: A recent overview. Eur J Med Chem 2017; 139:542-563. [DOI: 10.1016/j.ejmech.2017.08.010] [Citation(s) in RCA: 72] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2017] [Revised: 07/30/2017] [Accepted: 08/02/2017] [Indexed: 01/26/2023]
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21
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Pitsawong W, Haynes CA, Koder RL, Rodgers DW, Miller AF. Mechanism-Informed Refinement Reveals Altered Substrate-Binding Mode for Catalytically Competent Nitroreductase. Structure 2017; 25:978-987.e4. [PMID: 28578873 DOI: 10.1016/j.str.2017.05.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2016] [Revised: 04/02/2017] [Accepted: 05/05/2017] [Indexed: 01/25/2023]
Abstract
Nitroreductase (NR) from Enterobacter cloacae reduces diverse nitroaromatics including herbicides, explosives, and prodrugs, and holds promise for bioremediation, prodrug activation, and enzyme-assisted synthesis. We solved crystal structures of NR complexes with bound substrate or analog for each of its two half-reactions. We complemented these with kinetic isotope effect (KIE) measurements elucidating H-transfer steps essential to each half-reaction. KIEs indicate hydride transfer from NADH to the flavin consistent with our structure of NR with the NADH analog nicotinic acid adenine dinucleotide (NAAD). The KIE on reduction of p-nitrobenzoic acid (p-NBA) also indicates hydride transfer, and requires revision of prior computational mechanisms. Our mechanistic information provided a structural restraint for the orientation of bound substrate, placing the nitro group closer to the flavin N5 in the pocket that binds the amide of NADH. KIEs show that solvent provides a proton, enabling accommodation of different nitro group placements, consistent with the broad repertoire of NR.
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Affiliation(s)
- Warintra Pitsawong
- Department of Chemistry, University of Kentucky, 505 Rose Street, Lexington, KY 40506-0055, USA
| | - Chad A Haynes
- Department of Molecular and Cellular Biochemistry and Center for Structural Biology, University of Kentucky, 741 South Limestone Street, Lexington, KY 40536-0509, USA
| | - Ronald L Koder
- Department of Chemistry, University of Kentucky, 505 Rose Street, Lexington, KY 40506-0055, USA
| | - David W Rodgers
- Department of Molecular and Cellular Biochemistry and Center for Structural Biology, University of Kentucky, 741 South Limestone Street, Lexington, KY 40536-0509, USA.
| | - Anne-Frances Miller
- Department of Chemistry, University of Kentucky, 505 Rose Street, Lexington, KY 40506-0055, USA; Department of Molecular and Cellular Biochemistry and Center for Structural Biology, University of Kentucky, 741 South Limestone Street, Lexington, KY 40536-0509, USA.
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22
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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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23
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Osswald A, Sun Z, Grimm V, Ampem G, Riegel K, Westendorf AM, Sommergruber W, Otte K, Dürre P, Riedel CU. Three-dimensional tumor spheroids for in vitro analysis of bacteria as gene delivery vectors in tumor therapy. Microb Cell Fact 2015; 14:199. [PMID: 26655167 PMCID: PMC4676896 DOI: 10.1186/s12934-015-0383-5] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2015] [Accepted: 11/11/2015] [Indexed: 12/31/2022] Open
Abstract
Background Several studies in animal models demonstrated that obligate and facultative anaerobic bacteria of the genera Bifidobacterium, Salmonella, or Clostridium specifically colonize solid tumors. Consequently, these and other bacteria are discussed as live vectors to deliver therapeutic genes to inhibit tumor growth. Therapeutic approaches for cancer treatment using anaerobic bacteria have been investigated in different mouse models. In the present study, solid three-dimensional (3D) multicellular tumor spheroids (MCTS) of the colorectal adenocarcinoma cell line HT-29 were generated and tested for their potential to study prodrug-converting enzyme therapies using bacterial vectors in vitro. Results HT-29 MCTS resembled solid tumors displaying all relevant features with an outer zone of proliferating cells and hypoxic and apoptotic regions in the core. Upon incubation with HT-29 MCTS, Bifidobacterium bifidum S17 and Salmonella typhimurium YB1 selectively localized, survived and replicated in hypoxic areas inside MCTS. Furthermore, spores of the obligate anaerobe Clostridium sporogenes germinated in these hypoxic areas. To further evaluate the potential of MCTS to investigate therapeutic approaches using bacteria as gene delivery vectors, recombinant bifidobacteria expressing prodrug-converting enzymes were used. Expression of a secreted cytosine deaminase in combination with 5-fluorocytosine had no effect on growth of MCTS due to an intrinsic resistance of HT-29 cells to 5-fluorouracil, i.e. the converted drug. However, a combination of the prodrug CB1954 and a strain expressing a secreted chromate reductase effectively inhibited MCTS growth. Conclusions Collectively, the presented results indicate that MCTS are a suitable and reliable model to investigate live bacteria as gene delivery vectors for cancer therapy in vitro. Electronic supplementary material The online version of this article (doi:10.1186/s12934-015-0383-5) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Annika Osswald
- Institute of Microbiology and Biotechnology, University of Ulm, 89069, Ulm, Germany. .,Department of Lead Discovery, Boehringer Ingelheim RCV GmbH & Co KG, 1121, Vienna, Austria.
| | - Zhongke Sun
- Institute of Microbiology and Biotechnology, University of Ulm, 89069, Ulm, Germany. .,College of Life Sciences and Agriculture, Zhoukou Normal University, Chuanhui District, Zhoukou, 466001, People's Republic of China.
| | - Verena Grimm
- Institute of Microbiology and Biotechnology, University of Ulm, 89069, Ulm, Germany.
| | - Grace Ampem
- Institute of Microbiology and Biotechnology, University of Ulm, 89069, Ulm, Germany.
| | - Karin Riegel
- Institute of Microbiology and Biotechnology, University of Ulm, 89069, Ulm, Germany.
| | - Astrid M Westendorf
- Institute of Medical Microbiology, University Hospital Essen, University Duisburg-Essen, Essen, Germany.
| | - Wolfgang Sommergruber
- Department of Lead Discovery, Boehringer Ingelheim RCV GmbH & Co KG, 1121, Vienna, Austria.
| | - Kerstin Otte
- Institute of Applied Biotechnology, University of Applied Sciences Biberach, 88400, Biberach, Germany.
| | - Peter Dürre
- Institute of Microbiology and Biotechnology, University of Ulm, 89069, Ulm, Germany.
| | - Christian U Riedel
- Institute of Microbiology and Biotechnology, University of Ulm, 89069, Ulm, Germany.
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24
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Bai J, Yang J, Zhou Y, Yang Q. Structural basis of Escherichia coli nitroreductase NfsB triple mutants engineered for improved activity and regioselectivity toward the prodrug CB1954. Process Biochem 2015. [DOI: 10.1016/j.procbio.2015.08.012] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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25
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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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26
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Shahverdi AR, Mirzaie S, Rafii F, Kakavand M, Foroumadi A. Monoterpenes as nitrofurantoin resistance modulating agents: minimal structural requirements, molecular dynamics simulations, and the effect of piperitone on the emergence of nitrofurantoin resistance in Enterobacteriaceae. J Mol Model 2015; 21:198. [PMID: 26174760 DOI: 10.1007/s00894-015-2741-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2015] [Accepted: 06/24/2015] [Indexed: 01/10/2023]
Abstract
The effects of different monoterpenes and 2-cyclohexen-1-one on the antibacterial activity of nitrofurantoin against resistant Enterobacter cloacae, were compared and the minimal structural component of monoterpene required for the highest level of resistance-modulating activity was determined. Subinhibitory concentrations of all compounds tested enhanced the antibacterial activity of nitrofurantoin against E. cloacae to different extents. The highest synergistic effect was observed for the monoterpenes, like piperitone, which contained a conjugated ketone and C=C bond in their carbon ring structure. Piperitone also suppressed the emergence of nitrofurantoin-resistant strains of Enterobacteriaceae that were mutagenized by ethyl methanesulfonate. The modes of interaction of carvone, piperitone, and an enzyme inhibitor, benzoate, with nitroreductase were investigated by molecular docking and molecular dynamic (MD) simulation for 20 ns. MD simulation supported greater stability of the benzoate and monoterpene-nitroreductase (NR) complexes than of free NR. The results of this investigation are promising for the synthesis of more effective lead compounds to enhance the antibacterial activity of nitro drugs against resistant Enterobacter strains.
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Affiliation(s)
- Ahmad R Shahverdi
- Department of Pharmaceutical Biotechnology, Faculty of Pharmacy and Biotechnology Research Center, Tehran University of Medical Sciences, Tehran, 1417614411, Iran,
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27
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Transformation pathway of 2,4,6-trinitrotoluene by Escherichia coli nitroreductases and improvement of activity using structure-based mutagenesis. Process Biochem 2015. [DOI: 10.1016/j.procbio.2015.01.029] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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28
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The potential of clostridial spores as therapeutic delivery vehicles in tumour therapy. Res Microbiol 2015; 166:244-54. [DOI: 10.1016/j.resmic.2014.12.006] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2014] [Revised: 12/15/2014] [Accepted: 12/15/2014] [Indexed: 01/19/2023]
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29
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Song HN, Jeong DG, Bang SY, Paek SH, Park BC, Park SG, Woo EJ. Crystal structure of the fungal nitroreductase Frm2 from Saccharomyces cerevisiae. Protein Sci 2015; 24:1158-63. [PMID: 25864423 DOI: 10.1002/pro.2686] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2014] [Accepted: 03/31/2015] [Indexed: 11/09/2022]
Abstract
Nitroreductases are flavoenzymes that catalyze nitrocompounds and are widely utilized in industrial applications due to their detoxification potential and activation of biomedicinal prodrugs. Type I nitroreductases are classified into subgroups depending on the use of NADPH or NADH as the electron donor. Here, we report the crystal structure of the fungal nitroreductase Frm2 from Saccharomyces cerevisiae, one of the uncharacterized subgroups of proteins, to reveal its minimal architecture previously observed in bacterial nitroreductases such as CinD and YdjA. The structure lacks protruding helical motifs that form part of the cofactor and substrate binding site, resulting in an open and wide active site geometry. Arg82 is uniquely conserved in proximity to the substrate binding site in Frm2 homologues and plays a crucial role in the activity of the active site. Frm2 primarily utilizes NADH to reduce 4-NQO. Because missing helical elements are involved in the direct binding to the NAD(P)H in group A or group B in Type I family, Frm2 and its homologues may represent a distinctive subgroup with an altered binding mode for the reducing compound. This result provides a structural basis for the rational design of novel prodrugs with the ability to reduce nitrogen-containing hazardous molecules.
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Affiliation(s)
- Hyung-Nam Song
- Korea Research Institute of Bioscience and Biotechnology, Daejeon, 305-806, Republic of Korea.,Department of Biotechnology and Bioinformatics, Korea University, Sejong, 339-700, Republic of Korea
| | - Dae-Gwin Jeong
- Korea Research Institute of Bioscience and Biotechnology, Daejeon, 305-806, Republic of Korea.,Bio-Analytical Science Division, Korea University of Science and Technology (UST), Daejeon, Republic of Korea
| | - Seo-Young Bang
- Korea Research Institute of Bioscience and Biotechnology, Daejeon, 305-806, Republic of Korea
| | - Se-Hwan Paek
- Department of Biotechnology and Bioinformatics, Korea University, Sejong, 339-700, Republic of Korea
| | - Byoung-Chul Park
- Korea Research Institute of Bioscience and Biotechnology, Daejeon, 305-806, Republic of Korea.,Bio-Analytical Science Division, Korea University of Science and Technology (UST), Daejeon, Republic of Korea
| | - Sung-Goo Park
- Korea Research Institute of Bioscience and Biotechnology, Daejeon, 305-806, Republic of Korea.,Bio-Analytical Science Division, Korea University of Science and Technology (UST), Daejeon, Republic of Korea
| | - Eui-Jeon Woo
- Korea Research Institute of Bioscience and Biotechnology, Daejeon, 305-806, Republic of Korea.,Bio-Analytical Science Division, Korea University of Science and Technology (UST), Daejeon, Republic of Korea
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30
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Bai J, Zhou Y, Chen Q, Yang Q, Yang J. Altering the regioselectivity of a nitroreductase in the synthesis of arylhydroxylamines by structure-based engineering. Chembiochem 2015; 16:1219-25. [PMID: 25917861 DOI: 10.1002/cbic.201500070] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2015] [Indexed: 11/07/2022]
Abstract
Nitroreductases have great potential for the highly efficient reduction of aryl nitro compounds to arylhydroxylamines. However, regioselective reduction of the desired nitro group in polynitroarenes is still a challenge. Here, we describe the structure-based engineering of Escherichia coli nitroreductase NfsB to alter its regioselectivity, in order to achieve reduction of a target nitro group. When 2,4-dinitrotoluene was used as the substrate, the wild-type enzyme regioselectively reduced the 4-NO2 group, but the T41L/N71S/F124W mutant primarily reduced the 2-NO2 group, without loss of activity. The crystal structure of T41L/N71S/F124W and docking experiments indicated that the regioselectivity change (from 4-NO2 to 2-NO2 ) might result from the increased hydrophobicity of residues 41 and 124 (proximal to FMN) and conformational changes in residues 70 and 124.
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Affiliation(s)
- Jing Bai
- School of Life Science and Biotechnology, Dalian University of Technology, No. 2 Linggong Road, Dalian-116023 (China)
| | - Yong Zhou
- School of Software Technology, Dalian University of Technology, 321 Tuqiang Street, Development Zone, Dalian (China)
| | - Qi Chen
- School of Life Science and Biotechnology, Dalian University of Technology, No. 2 Linggong Road, Dalian-116023 (China)
| | - Qing Yang
- School of Life Science and Biotechnology, Dalian University of Technology, No. 2 Linggong Road, Dalian-116023 (China)
| | - Jun Yang
- School of Life Science and Biotechnology, Dalian University of Technology, No. 2 Linggong Road, Dalian-116023 (China).
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31
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Heap JT, Theys J, Ehsaan M, Kubiak AM, Dubois L, Paesmans K, Van Mellaert L, Knox R, Kuehne SA, Lambin P, Minton NP. Spores of Clostridium engineered for clinical efficacy and safety cause regression and cure of tumors in vivo. Oncotarget 2015; 5:1761-9. [PMID: 24732092 PMCID: PMC4039107 DOI: 10.18632/oncotarget.1761] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Spores of some species of the strictly anaerobic bacteria Clostridium naturally target and partially lyse the hypoxic cores of tumors, which tend to be refractory to conventional therapies. The anti-tumor effect can be augmented by engineering strains to convert a non-toxic prodrug into a cytotoxic drug specifically at the tumor site by expressing a prodrug-converting enzyme (PCE). Safe doses of the favored prodrug CB1954 lead to peak concentrations of 6.3 μM in patient sera, but at these concentration(s) known nitroreductase (NTR) PCEs for this prodrug show low activity. Furthermore, efficacious and safe Clostridium strains that stably express a PCE have not been reported. Here we identify a novel nitroreductase from Neisseria meningitidis, NmeNTR, which is able to activate CB1954 at clinically-achievable serum concentrations. An NmeNTR expression cassette, which does not contain an antibiotic resistance marker, was stably localized to the chromosome of Clostridium sporogenes using a new integration method, and the strain was disabled for safety and containment by making it a uracil auxotroph. The efficacy of Clostridium-Directed Enzyme Prodrug Therapy (CDEPT) using this system was demonstrated in a mouse xenograft model of human colon carcinoma. Substantial tumor suppression was achieved, and several animals were cured. These encouraging data suggest that the novel enzyme and strain engineering approach represent a promising platform for the clinical development of CDEPT.
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Affiliation(s)
- John T Heap
- Clostridia Research Group, Centre for Biomolecular Sciences, School of Life Sciences, The University of Nottingham, University Park, Nottingham, UK
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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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Voak AA, Gobalakrishnapillai V, Seifert K, Balczo E, Hu L, Hall BS, Wilkinson SR. An essential type I nitroreductase from Leishmania major can be used to activate leishmanicidal prodrugs. J Biol Chem 2013; 288:28466-76. [PMID: 23946481 DOI: 10.1074/jbc.m113.494781] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Nitroaromatic prodrugs are used to treat a range of microbial infections with selectivity achieved by specific activation reactions. For trypanosomatid parasites, this is mediated by type I nitroreductases. Here, we demonstrate that the causative agent of leishmaniasis, Leishmania major, expresses an FMN-containing nitroreductase (LmNTR) that metabolizes a wide range of substrates, and based on electron donor and acceptor preferences, it may function as an NADH:quinone oxidoreductase. Using gene deletion approaches, we demonstrate that this activity is essential to L. major promastigotes, the parasite forms found in the insect vector. Intriguingly, LmNTR(+/-) heterozygote promastigote parasites could readily differentiate into infectious metacyclic cells but these were unable to establish infections in cultured mammalian cells and caused delayed pathology in mice. Furthermore, we exploit the LmNTR activity evaluating a library of nitrobenzylphosphoramide mustards using biochemical and phenotypic screens. We identify a subset of compounds that display significant growth inhibitory properties against the intracellular parasite form found in the mammalian hosts. The leishmanicidal activity was shown to be LmNTR-specific as the LmNTR(+/-) heterozygote promastigotes displayed resistance to the most potent mustards. We conclude that LmNTR can be targeted for drug development by exploiting its prodrug activating property or by designing specific inhibitors to block its endogenous function.
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Affiliation(s)
- Andrew A Voak
- From the Queen Mary Pre-Clinical Drug Discovery Group, School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London E1 4NS, United Kingdom
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Lehouritis P, Springer C, Tangney M. Bacterial-directed enzyme prodrug therapy. J Control Release 2013; 170:120-31. [DOI: 10.1016/j.jconrel.2013.05.005] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2013] [Revised: 05/08/2013] [Accepted: 05/09/2013] [Indexed: 01/21/2023]
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Residue Phe42 is critical for the catalytic activity of Escherichia coli major nitroreductase NfsA. Biotechnol Lett 2013; 35:1693-700. [PMID: 23801116 DOI: 10.1007/s10529-013-1262-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2013] [Accepted: 05/31/2013] [Indexed: 10/26/2022]
Abstract
The major O2-insensitive nitroreductase (NfsA) of Escherichia coli shares low sequence homology but similar biochemical and structural features with NfsB, the E. coli minor O2-insensitive nitroreductase. A structural comparison revealed Phe42 was present in the active site of NfsA but not NfsB. F42Y, F42N and F42A were generated and had decreased activity toward nitrofurazone by 52, 96, and 99%, respectively. The kinetic parameters for other nitroaromatic substrates were also determined. Compared to wild type, the mutants did not have significantly altered K(m)s, but had dramatically decreased k(cat) and k(cat)/K(m) values. Far-UV CD spectral analysis of the mutants suggested that there were no significant conformational changes however F42A and F42N had changes from 208 to 222 nm, which was attributed to loss of helix content. These findings revealed that Phe42 is important for maintaining NfsA activity and structure.
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Robins KJ, Hooks DO, Rehm BHA, Ackerley DF. Escherichia coli NemA is an efficient chromate reductase that can be biologically immobilized to provide a cell free system for remediation of hexavalent chromium. PLoS One 2013; 8:e59200. [PMID: 23527133 PMCID: PMC3596305 DOI: 10.1371/journal.pone.0059200] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2012] [Accepted: 02/14/2013] [Indexed: 11/19/2022] Open
Abstract
Hexavalent chromium is a serious and widespread environmental pollutant. Although many bacteria have been identified that can transform highly water-soluble and toxic Cr(VI) to insoluble and relatively non-toxic Cr(III), bacterial bioremediation of Cr(VI) pollution is limited by a number of issues, in particular chromium toxicity to the remediating cells. To address this we sought to develop an immobilized enzymatic system for Cr(VI) remediation. To identify novel Cr(VI) reductase enzymes we first screened cell extracts from an Escherichia coli library of soluble oxidoreductases derived from a range of bacteria, but found that a number of these enzymes can reduce Cr(VI) indirectly, via redox intermediates present in the crude extracts. Instead, activity assays for 15 candidate enzymes purified as His6-tagged proteins identified E. coli NemA as a highly efficient Cr(VI) reductase (kcat/KM = 1.1×105 M−1s−1 with NADH as cofactor). Fusion of nemA to the polyhydroxyalkanoate synthase gene phaC from Ralstonia eutropha enabled high-level biosynthesis of functionalized polyhydroxyalkanoate granules displaying stable and active NemA on their surface. When these granules were combined with either Bacillus subtilis glucose dehydrogenase or Candida boidinii formate dehydrogenase as a cofactor regenerating partner, high levels of chromate transformation were observed with only low initial concentrations of expensive NADH cofactor being required, the overall reaction being powered by consumption of the cheap sacrificial substrates glucose or formic acid, respectively. This system therefore offers promise as an economic solution for ex situ Cr(VI) remediation.
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Affiliation(s)
- Katherine J. Robins
- School of Biological Sciences, Victoria University of Wellington, Kelburn Parade, Wellington, New Zealand
| | - David O. Hooks
- Institute of Fundamental Sciences, Massey University, Tennent Drive, Palmerston North, New Zealand
- MacDiarmid Institute for Advanced Materials and Nanotechnology, Victoria University of Wellington, Kelburn Parade, Wellington, New Zealand
| | - Bernd H. A. Rehm
- Institute of Fundamental Sciences, Massey University, Tennent Drive, Palmerston North, New Zealand
- MacDiarmid Institute for Advanced Materials and Nanotechnology, Victoria University of Wellington, Kelburn Parade, Wellington, New Zealand
| | - David F. Ackerley
- School of Biological Sciences, Victoria University of Wellington, Kelburn Parade, Wellington, New Zealand
- Centre for Biodiscovery, Victoria University of Wellington, Kelburn Parade, Wellington, New Zealand
- * E-mail:
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Prosser GA, Copp JN, Mowday AM, Guise CP, Syddall SP, Williams EM, Horvat CN, Swe PM, Ashoorzadeh A, Denny WA, Smaill JB, Patterson AV, Ackerley DF. Creation and screening of a multi-family bacterial oxidoreductase library to discover novel nitroreductases that efficiently activate the bioreductive prodrugs CB1954 and PR-104A. Biochem Pharmacol 2013; 85:1091-103. [PMID: 23399641 DOI: 10.1016/j.bcp.2013.01.029] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2012] [Revised: 01/28/2013] [Accepted: 01/30/2013] [Indexed: 01/14/2023]
Abstract
Two potentially complementary approaches to improve the anti-cancer strategy gene-directed enzyme prodrug therapy (GDEPT) are discovery of more efficient prodrug-activating enzymes, and development of more effective prodrugs. Here we demonstrate the utility of a flexible screening system based on the Escherichia coli SOS response to evaluate novel nitroreductase enzymes and prodrugs in concert. To achieve this, a library of 47 candidate genes representing 11 different oxidoreductase families was created and screened to identify the most efficient activators of two different nitroaromatic prodrugs, CB1954 and PR-104A. The most catalytically efficient nitroreductases were found in the NfsA and NfsB enzyme families, with NfsA homologues generally more active than NfsB. Some members of the AzoR, NemA and MdaB families also exhibited low-level activity with one or both prodrugs. The results of SOS screening in our optimised E. coli reporter strain SOS-R2 were generally predictive of the ability of nitroreductase candidates to sensitise E. coli to CB1954, and of the kcat/Km for each prodrug substrate at a purified protein level. However, we also found that not all nitroreductases express stably in human (HCT-116 colon carcinoma) cells, and that activity at a purified protein level did not necessarily predict activity in stably transfected HCT-116. These results highlight a need for all enzyme-prodrug partners for GDEPT to be assessed in the specific context of the vector and cell line that they are intended to target. Nonetheless, our oxidoreductase library and optimised screens provide valuable tools to identify preferred nitroreductase-prodrug combinations to advance to preclinical evaluation.
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Affiliation(s)
- Gareth A Prosser
- School of Biological Sciences, Victoria University of Wellington, Kelburn Parade, Wellington, New Zealand
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Guo T, Cui L, Shen J, Zhu W, Xu Y, Qian X. A highly sensitive long-wavelength fluorescence probe for nitroreductase and hypoxia: selective detection and quantification. Chem Commun (Camb) 2013; 49:10820-2. [DOI: 10.1039/c3cc45367g] [Citation(s) in RCA: 116] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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Martínez-Júlvez M, Rojas AL, Olekhnovich I, Espinosa Angarica V, Hoffman PS, Sancho J. Structure of RdxA--an oxygen-insensitive nitroreductase essential for metronidazole activation in Helicobacter pylori. FEBS J 2012; 279:4306-17. [PMID: 23039228 DOI: 10.1111/febs.12020] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2012] [Revised: 09/26/2012] [Accepted: 10/03/2012] [Indexed: 11/27/2022]
Abstract
UNLABELLED The RdxA oxygen-insensitive nitroreductase of the human gastric pathogen Helicobacter pylori is responsible for the susceptibility of this organism to the redox active prodrug metronidazole [2-(2-methyl-5-nitro-1H-imidazol-1-yl)ethanol]. Loss-of-function mutations in rdxA are primarily responsible for resistance to this therapeutic. RdxA exhibits potent NADPH oxidase activity under aerobic conditions and metronidazole reductase activity under strictly anaerobic conditions. In the present study, we report the crystal structure of RdxA, which is a homodimer exhibiting domain swapping and containing two molecules of FMN bound at the dimer interface. We have found a gap between the side chain of Tyr47 and the isoalloxazine ring of FMN that appears to be appropriate for substrate binding. The structure does not include residues 97-128, which correspond to a locally unstable part of the NTR from Escherichia coli, and might be involved in cofactor binding. Comparison of H. pylori RdxA with other oxidoreductases of known structure suggests that RdxA may belong to a new subgroup of oxidoreductases in which a cysteine side chain close to the FMN cofactor could be involved in the reductive activity. In this respect, the mutation of C159 to A or S (C159A/S) has resulted in a loss of metronidazole reductase activity but not NADPH oxidase activity. The RdxA structure enables the interpretation of the many loss-of-function mutations described previously, including those affecting C159, a residue whose interaction with FMN is required for the nitroreduction of metronidazole. The present studies provide unique insights into the redox behaviour of the flavin in this key enzyme for metronidazole activation, including a potential use in gene therapy. DATABASE Structural data have been deposited in the Protein Data Bank under accession number 3QDL.
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Affiliation(s)
- Marta Martínez-Júlvez
- Departamento de Bioquímica y Biología Molecular y Celular, Facultad de Ciencias, Universidad de Zaragoza, Zaragoza, Spain
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40
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Isayev O, Crespo-Hernández CE, Gorb L, Hill FC, Leszczynski J. In silico structure-function analysis of E. cloacae nitroreductase. Proteins 2012; 80:2728-41. [PMID: 22865652 DOI: 10.1002/prot.24157] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2012] [Revised: 04/26/2012] [Accepted: 07/05/2012] [Indexed: 01/18/2023]
Abstract
Reduction, catalyzed by the bacterial nitroreductases, is the quintessential first step in the biodegradation of a variety of nitroaromatic compounds from contaminated waters and soil. The Enterobacter cloacae nitroreductase (EcNR) enzyme is considered as a prospective biotechnological tool for bioremediation of hazardous nitroaromatic compounds. Using diverse computational methods, we obtain insights into the structural basis of activity and mechanism of its function. We have performed molecular dynamics simulation of EcNR in three different states (free EcNR in oxidized form, fully reduced EcNR with benzoate inhibitor and fully reduced EcNR with nitrobenzene) in explicit solvent and with full electrostatics. Principal Component Analysis (PCA) of the variance-covariance matrix showed that the complexed nitroreductase becomes more flexible overall upon complexation, particularly helix H6, in the vicinity of the binding site. A multiple sequence alignment was also constructed in order to examine positional constraints on substitution in EcNR. Five regions which are highly conserved within the flavin mononucleotide (FMN) binding site were identified. Obtained results and their implications for EcNR functioning are discussed, and new plausible mechanism has been proposed.
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Affiliation(s)
- Olexandr Isayev
- Department of Chemistry, Case Western Reserve University, Cleveland, OH 44106, USA.
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41
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Targeting the substrate preference of a type I nitroreductase to develop antitrypanosomal quinone-based prodrugs. Antimicrob Agents Chemother 2012; 56:5821-30. [PMID: 22948871 DOI: 10.1128/aac.01227-12] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Nitroheterocyclic prodrugs are used to treat infections caused by Trypanosoma cruzi and Trypanosoma brucei. A key component in selectivity involves a specific activation step mediated by a protein homologous with type I nitroreductases, enzymes found predominantly in prokaryotes. Using data from determinations based on flavin cofactor, oxygen-insensitive activity, substrate range, and inhibition profiles, we demonstrate that NTRs from T. cruzi and T. brucei display many characteristics of their bacterial counterparts. Intriguingly, both enzymes preferentially use NADH and quinones as the electron donor and acceptor, respectively, suggesting that they may function as NADH:ubiquinone oxidoreductases in the parasite mitochondrion. We exploited this preference to determine the trypanocidal activity of a library of aziridinyl benzoquinones against bloodstream-form T. brucei. Biochemical screens using recombinant NTR demonstrated that several quinones were effective substrates for the parasite enzyme, having K(cat)/K(m) values 2 orders of magnitude greater than those of nifurtimox and benznidazole. In tests against T. brucei, antiparasitic activity mirrored the biochemical data, with the most potent compounds generally being preferred enzyme substrates. Trypanocidal activity was shown to be NTR dependent, as parasites with elevated levels of this enzyme were hypersensitive to the aziridinyl agent. By unraveling the biochemical characteristics exhibited by the trypanosomal NTRs, we have shown that quinone-based compounds represent a class of trypanocidal compound.
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42
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Swe PM, Copp JN, Green LK, Guise CP, Mowday AM, Smaill JB, Patterson AV, Ackerley DF. Targeted mutagenesis of the Vibrio fischeri flavin reductase FRase I to improve activation of the anticancer prodrug CB1954. Biochem Pharmacol 2012; 84:775-83. [PMID: 22796568 DOI: 10.1016/j.bcp.2012.07.002] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2012] [Revised: 07/03/2012] [Accepted: 07/05/2012] [Indexed: 01/22/2023]
Abstract
Phase I/II cancer gene therapy trials of the Escherichia coli nitroreductase NfsB in partnership with the prodrug CB1954 [5-(aziridin-1-yl)-2,4-dinitrobenzamide] have indicated that CB1954 toxicity is dose-limiting at concentrations far below the enzyme K(M). Here we report that the flavin reductase FRase I from Vibrio fischeri is also a CB1954 nitroreductase, which has a substantially lower apparent K(M) than E. coli NfsB. To enhance the activity of FRase I with CB1954 we used targeted mutagenesis and an E. coli SOS reporter strain to engineer single- and multi-residue variants that possess a substantially reduced apparent K(M) and an increased k(cat)/K(M) relative to the wild type enzyme. In a bacteria-delivered model for enzyme prodrug therapy, the engineered FRase I variants were able to kill human colon carcinoma (HCT-116) cells at significantly lower CB1954 concentrations than wild type FRase I or E. coli NfsB.
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Affiliation(s)
- P M Swe
- School of Biological Sciences, Victoria University of Wellington, Kelburn Parade, Wellington, New Zealand.
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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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44
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LinWu SW, Wu CA, Peng FC, Wang AHJ. Structure-based development of bacterial nitroreductase against nitrobenzodiazepine-induced hypnosis. Biochem Pharmacol 2012; 83:1690-9. [PMID: 22445794 DOI: 10.1016/j.bcp.2012.03.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2012] [Revised: 03/04/2012] [Accepted: 03/06/2012] [Indexed: 12/01/2022]
Abstract
Nitrobenzodiazepine (NBDZ) is an addictive drug of the abused substances that causes severe neurological effects and even death. Bacterial type I nitroreductase NfsB (EC 1.5.1.34) has been reported to catalyze NBDZ into inactive metabolite 7-amino-benzodiazepine (7ABDZ) with promising activity, so as to become an attractive candidate for treatment of NBDZ overdose and addiction. Here, we investigate the nitroreduction of an NBDZ, flunitrazepam (FZ), by various mutants of NfsB designed from the solved crystal structure and characterize their in vitro and in vivo potency. Conformational changes occurred in the active site of N71S/F124W in contrast to the wild-type, including the flipping on the aromatic rings of W124 and F70 as well as the extension on the hydrogen bond network between flavin mononucleotide (FMN) and S71, which allow the significant enlargement in the active site pocket. In the complex structure of N71S/F124W and nicotinamide (NIA), stacking sandwich attractions of W124-FMN-NIA were also found, implying the importance of W124 in substrate accessibility. Consequently, N71S/F124W exhibited increased 7AFZ production in vitro with nearly no toxicity and reduced 50% sleeping time (hypnosis) in vivo. Taken together, we demonstrate for the first time that N71S/F124W can serve as an effective antidote for NBDZ-induced hypnosis and provide the molecular basis for designing NfsB and the like in the future.
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Affiliation(s)
- Shiuan-Woei LinWu
- Institute of Biological Chemistry, Academia Sinica, Taipei 115, Taiwan
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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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46
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Gwenin VV, Gwenin CD, Kalaji M. Colloidal gold modified with a genetically engineered nitroreductase: toward a novel enzyme delivery system for cancer prodrug therapy. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2011; 27:14300-7. [PMID: 22014024 DOI: 10.1021/la202951p] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Directed enzyme prodrug therapy is an extensive area of research in cancer chemotherapy. Although very promising, the current directed approaches are still hampered by inefficient enzyme expression and tumor targeting. This work investigates the viability of using metal nanoparticles as a novel delivery vehicle for prodrug-activating enzymes. Using genetically incorporated amino acid sequences, a nitroreductase from E. coli was directly immobilized onto a 50 nm gold colloid, as confirmed by gel electrophoresis, DLS, and UV-vis spectroscopy. The resulting conjugates showed excellent stability in changing proton and sodium chloride environments, including PBS at 37 °C. Remarkably, the immobilized nitroreductase retained more than 99% activity to the CB1954 prodrug without the need for stabilizers. This work provides the foundation for attaching prodrug-activating enzymes to metal nanoparticles for future use in directed enzyme prodrug therapy.
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Affiliation(s)
- Vanessa V Gwenin
- School of Chemistry, Bangor University, Bangor, Gwynedd, LL57 2DG, Wales, United Kingdom
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Chen CF, Chu CY, Chen TH, Lee SJ, Shen CN, Hsiao CD. Establishment of a transgenic zebrafish line for superficial skin ablation and functional validation of apoptosis modulators in vivo. PLoS One 2011; 6:e20654. [PMID: 21655190 PMCID: PMC3105106 DOI: 10.1371/journal.pone.0020654] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2010] [Accepted: 05/09/2011] [Indexed: 01/31/2023] Open
Abstract
Background Zebrafish skin is composed of enveloping and basal layers which form a first-line defense system against pathogens. Zebrafish epidermis contains ionocytes and mucous cells that aid secretion of acid/ions or mucous through skin. Previous studies demonstrated that fish skin is extremely sensitive to external stimuli. However, little is known about the molecular mechanisms that modulate skin cell apoptosis in zebrafish. Methodology/Principal Findings This study aimed to create a platform to conduct conditional skin ablation and determine if it is possible to attenuate apoptotic stimuli by overexpressing potential apoptosis modulating genes in the skin of live animals. A transgenic zebrafish line of Tg(krt4:NTR-hKikGR)cy17 (killer line), which can conditionally trigger apoptosis in superficial skin cells, was first established. When the killer line was incubated with the prodrug metrodinazole, the superficial skin displayed extensive apoptosis as judged by detection of massive TUNEL- and active caspase 3-positive signals. Great reductions in NTR-hKikGR+ fluorescent signals accompanied epidermal cell apoptosis. This indicated that NTR-hKikGR+ signal fluorescence can be utilized to evaluate apoptotic events in vivo. After removal of metrodinazole, the skin integrity progressively recovered and NTR-hKikGR+ fluorescent signals gradually restored. In contrast, either crossing the killer line with testing lines or transiently injecting the killer line with testing vectors that expressed human constitutive active Akt1, mouse constitutive active Stat3, or HPV16 E6 element displayed apoptosis-resistant phenotypes to cytotoxic metrodinazole as judged by the loss of reduction in NTR-hKikGR+ fluorescent signaling. Conclusion/Significance The killer/testing line binary system established in the current study demonstrates a nitroreductase/metrodinazole system that can be utilized to conditionally perform skin ablation in a real-time manner, and provides a valuable tool to visualize and quantify the anti-apoptotic potential of interesting target genes in vivo. The current work identifies a potential use for transgenic zebrafish as a high-throughput platform to validate potential apoptosis modulators in vivo.
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Affiliation(s)
- Chi-Fang Chen
- Institute of Bioscience and Biotechnology, National Taiwan Ocean University, Keelung, Taiwan
- Department of Bioscience Technology, Chung Yuan Christian University, Chung-Li, Taiwan
| | - Che-Yu Chu
- Department of Bioscience Technology, Chung Yuan Christian University, Chung-Li, Taiwan
| | - Te-Hao Chen
- National Museum of Marine Biology and Aquarium, Pingtung, Taiwan
| | - Shyh-Jye Lee
- Institute of Zoology, National Taiwan University, Taipei, Taiwan
| | - Chia-Ning Shen
- Institute of Bioscience and Biotechnology, National Taiwan Ocean University, Keelung, Taiwan
- Genome Research Center, Academia Sinica, NanKang, Taipei, Taiwan
- * E-mail: (C-NS); (C-DH)
| | - Chung-Der Hsiao
- Department of Bioscience Technology, Chung Yuan Christian University, Chung-Li, Taiwan
- Center for Nanotechnology, Chung Yuan Christian University, Chung-Li, Taiwan
- * E-mail: (C-NS); (C-DH)
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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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Middleton MR, Knox R, Cattell E, Oppermann U, Midgley R, Ali R, Auton T, Agarwal R, Anderson D, Sarker D, Judson I, Osawa T, Spanswick VJ, Davies S, Hartley JA, Kerr DJ. Quinone oxidoreductase-2-mediated prodrug cancer therapy. Sci Transl Med 2010; 2:40ra50. [PMID: 20630857 DOI: 10.1126/scitranslmed.3000615] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
DNA-damaging agents are widely used in cancer treatment despite their lack of tumor specificity. Human NQO2 (quinone oxidoreductase-2) is an atypical oxidoreductase because no endogenous electron donor has been identified to date. The enzyme converts CB1954 [5-(aziridin-1-yl)-2,4-dinitrobenzamide], in the presence of the synthetic nicotinamide cofactor analog EP0152R, to a cytotoxic bifunctional alkylating agent. NQO2 activity in hepatocellular tumor tissue is higher than that in other cancer types by a factor of 6 and higher than that in bone marrow by a factor of 20. Structural data from x-ray crystallography and nuclear magnetic resonance spectroscopy allowed us to construct a model of CB1954 and EP0152R binding to NQO2, which suggested an optimal infusion schedule for a phase I trial combining the two agents. Thirty-two patients were treated, and diarrhea and serum transaminase concentrations defined a maximum tolerated dose for the drug combination. There was a clear pharmacokinetic interaction, with EP0152R inducing a marked increase in clearance of CB1954, in keeping with model predictions. We detected DNA interstrand cross-links caused by nitroreduced CB1954 in tumor biopsies from treated patients, demonstrating that the activated prodrug exerts its cytotoxic properties through DNA base alkylation.
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Affiliation(s)
- Mark R Middleton
- Department of Medical Oncology, Churchill Hospital, Headington, Oxford OX3 7LJ, UK.
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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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