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Weingarten P, Thomas SR, Luiza de Andrade Querino A, Halama K, Kränzlein M, Casini A, Rieger B. A graft-to strategy of poly(vinylphosphonates) on dopazide-coated gold nanoparticles using in situ catalyst activation. RSC Adv 2024; 14:8145-8149. [PMID: 38464693 PMCID: PMC10921843 DOI: 10.1039/d4ra01116c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2024] [Accepted: 03/04/2024] [Indexed: 03/12/2024] Open
Abstract
A modular synthetic pathway for poly(diethyl vinylphosphonates) grafting-to gold nanoparticles is presented. Utilising an azide-dopamine derivative as nanoparticle coating agent, alkyne-azide click conditions were used to covalently tether the polymer to gold nanoparticles leading to stable and well distributed colloids for different applications.
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Affiliation(s)
- Philipp Weingarten
- WACKER-Chair of Macromolecular Chemistry, Catalysis Research Center, School of Natural Sciences, Department of Chemistry, Technical University of Munich Lichtenbergstraße 4 D-85748 Garching b. München Germany
| | - Sophie R Thomas
- Chair of Medicinal and Bioinorganic Chemistry, Department of Chemistry, School of Natural Sciences, Technical University of Munich Lichtenbergstraße 4 D-85748 Garching b. München Germany
| | - Ana Luiza de Andrade Querino
- Chair of Medicinal and Bioinorganic Chemistry, Department of Chemistry, School of Natural Sciences, Technical University of Munich Lichtenbergstraße 4 D-85748 Garching b. München Germany
- Department of Chemistry, Universidade Federal de Minas Gerais Belo Horizonte MG 31270-901 Brazil
| | - Kerstin Halama
- WACKER-Chair of Macromolecular Chemistry, Catalysis Research Center, School of Natural Sciences, Department of Chemistry, Technical University of Munich Lichtenbergstraße 4 D-85748 Garching b. München Germany
| | - Moritz Kränzlein
- WACKER-Chair of Macromolecular Chemistry, Catalysis Research Center, School of Natural Sciences, Department of Chemistry, Technical University of Munich Lichtenbergstraße 4 D-85748 Garching b. München Germany
| | - Angela Casini
- Chair of Medicinal and Bioinorganic Chemistry, Department of Chemistry, School of Natural Sciences, Technical University of Munich Lichtenbergstraße 4 D-85748 Garching b. München Germany
| | - Bernhard Rieger
- WACKER-Chair of Macromolecular Chemistry, Catalysis Research Center, School of Natural Sciences, Department of Chemistry, Technical University of Munich Lichtenbergstraße 4 D-85748 Garching b. München Germany
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2
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da Silva IV, Pimpão C, Paccetti-Alves I, Thomas SR, Barateiro A, Casini A, Soveral G. Blockage of aquaporin-3 peroxiporin activity by organogold compounds affects melanoma cell adhesion, proliferation and migration. J Physiol 2024. [PMID: 38323926 DOI: 10.1113/jp284155] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2023] [Accepted: 01/23/2024] [Indexed: 02/08/2024] Open
Abstract
Aquaporin-3 (AQP3) is a membrane channel with dual aquaglyceroporin/peroxiporin activity, facilitating the diffusion of water, glycerol and H2 O2 across cell membranes. AQP3 shows aberrant expression in melanoma and its role in cell adhesion, migration and proliferation is well described. Gold compounds were shown to modulate AQP3 activity with reduced associated toxicity, making them promising molecules for cancer therapy. In this study, we validated the phenotype resulting from AQP3-silencing of two melanoma cell lines, MNT-1 and A375, which resulted in decreased H2 O2 permeability. Subsequently, the AQP3 inhibitory effect of a new series of organogold compounds derived from Auphen, a potent AQP3 inhibitor, was first evaluated in red blood cells (RBCs) that highly express AQP3, and then in HEK-293T cells with AQP3 overexpression to ascertain the compounds' specificity. The first screening in RBCs unveiled two organogold compounds as promising blockers of AQP3 permeability. Moderate reduction of glycerol permeability but drastic inhibition of H2 O2 permeability was detected for some of the gold derivatives in both AQP3-overexpressing cells and human melanoma cell lines. Additionally, all compounds were effective in impairing cell adhesion, proliferation and migration, although in a cell type-dependent manner. In conclusion, our data show that AQP3 peroxiporin activity is crucial for melanoma progression and highlight organogold compounds as promising AQP3 inhibitors with implications in melanoma cell adhesion, proliferation and migration, unveiling their potential as anticancer drugs against AQP3-overexpressing tumours. KEY POINTS: AQP3 affects cellular redox balance. Gold compounds inhibit AQP3 permeability in melanoma cells. AQP3 is involved in cell adhesion, proliferation and migration of melanoma. Blockage of AQP3 peroxiporin activity impairs melanoma cell migration. Gold compounds are potential anticancer drug leads for AQP3-overexpressing cancers.
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Affiliation(s)
- Inês V da Silva
- Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy, Universidade de Lisboa, Lisboa, Portugal
- Department of Pharmaceutical Sciences and Medicines, Faculty of Pharmacy, Universidade de Lisboa, Lisboa, Portugal
| | - Catarina Pimpão
- Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy, Universidade de Lisboa, Lisboa, Portugal
- Department of Pharmaceutical Sciences and Medicines, Faculty of Pharmacy, Universidade de Lisboa, Lisboa, Portugal
| | - Inês Paccetti-Alves
- Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy, Universidade de Lisboa, Lisboa, Portugal
- Department of Pharmaceutical Sciences and Medicines, Faculty of Pharmacy, Universidade de Lisboa, Lisboa, Portugal
| | - Sophie R Thomas
- Department of Chemistry, School of Natural Sciences, Technical University of Munich, Garching bei München, Germany
| | - Andreia Barateiro
- Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy, Universidade de Lisboa, Lisboa, Portugal
- Department of Pharmaceutical Sciences and Medicines, Faculty of Pharmacy, Universidade de Lisboa, Lisboa, Portugal
| | - Angela Casini
- Department of Chemistry, School of Natural Sciences, Technical University of Munich, Garching bei München, Germany
| | - Graça Soveral
- Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy, Universidade de Lisboa, Lisboa, Portugal
- Department of Pharmaceutical Sciences and Medicines, Faculty of Pharmacy, Universidade de Lisboa, Lisboa, Portugal
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de Andrade Querino AL, de Sousa AM, Thomas SR, de Lima GM, Dittz D, Casini A, do Monte-Neto RL, Silva H. Organogold(III)-dithiocarbamate compounds and their coordination analogues as anti-tumor and anti-leishmanial metallodrugs. J Inorg Biochem 2023; 247:112346. [PMID: 37536162 DOI: 10.1016/j.jinorgbio.2023.112346] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Revised: 07/18/2023] [Accepted: 07/27/2023] [Indexed: 08/05/2023]
Abstract
The limited chemical stability of gold(III)-based compounds in physiological environment has been a challenge in drug discovery, and organometallic chemistry might provide the solution to overcome this issue. In this work, four novel cationic organogold(III)-dithiocarbamate complexes of general structure [(C^N)AuIIIDTC]PF6 (C1a - C4a, DTC = dithiocarbamate, L1 - L4, C^N = 2-anilinopyridine) are presented, and compared to their coordination gold(III)-dithiocarbamate analogues [AuIIIDTCCl2] (C1b - C4b), as potential anti-cancer and anti-leishmanial drugs. Most of the complexes effectively inhibited cancer cell growth, notably C3a presented anti-proliferative effect in the nanomolar range against breast cancer (MCF-7 and MDA-MB-231 cells with moderate selectivity. Pro-apoptotic studies on treated MCF-7 cells showed a high population of cells in early apoptosis. Reactivity studies of C3a towards model thiols (N-acetyl-L-cysteine) refer to a possible mode of action involving bonding between the organogold(III)-core and the thiolate. In the scope of neglected diseases, gold complexes are emerging as promising therapeutic alternatives against leishmaniasis. In this regard, all gold(III)-dithiocarbamate complexes presented anti-leishmanial activity against at least one Leishmania species. Complexes C1a, C4a, C1b, C4b were active against all tested parasites with IC50 values varying between 0.12 and 42 μM, and, overall, organometallic compounds presented more intriguing inhibition profiles. For C4a selectivity over 500-fold for L. braziliensis; even higher than the reference anti-leishmanial drug amphotericin B. Overall, our findings revealed that the organogold(III) moiety significantly amplified the anti-cancer and anti-leishmanial effects with respect to the coordination analogues; thus, showing the great potential of organometallic chemistry in metallodrug-based chemotherapy for cancer and leishmaniasis.
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Affiliation(s)
- Ana Luiza de Andrade Querino
- Laboratório de Síntese e Interações Bioinorgânicas (SibLab), Department of Chemistry, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil; Chair of Medicinal and Bioinorganic Chemistry, Department of Chemistry, Technical University of Munich, Garching b. Munich, Germany.
| | - Alessandra Mara de Sousa
- RdM Lab - Biotechnology Applied to Pathogens Research Group, Instituto René Rachou, Fundação Oswaldo Cruz, Belo Horizonte, Brazil
| | - Sophie R Thomas
- Chair of Medicinal and Bioinorganic Chemistry, Department of Chemistry, Technical University of Munich, Garching b. Munich, Germany
| | - Geraldo Magela de Lima
- Laboratório de Síntese e Interações Bioinorgânicas (SibLab), Department of Chemistry, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Dalton Dittz
- Department of Biochemistry and Pharmacology, Universidade Federal do Piaui, Teresina, Brazil
| | - Angela Casini
- Chair of Medicinal and Bioinorganic Chemistry, Department of Chemistry, Technical University of Munich, Garching b. Munich, Germany
| | - Rubens Lima do Monte-Neto
- RdM Lab - Biotechnology Applied to Pathogens Research Group, Instituto René Rachou, Fundação Oswaldo Cruz, Belo Horizonte, Brazil
| | - Heveline Silva
- Laboratório de Síntese e Interações Bioinorgânicas (SibLab), Department of Chemistry, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil.
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Scalcon V, Bonsignore R, Aupič J, Thomas SR, Folda A, Heidecker AA, Pöthig A, Magistrato A, Casini A, Rigobello MP. Exploring the Anticancer Activity of Tamoxifen-Based Metal Complexes Targeting Mitochondria. J Med Chem 2023. [PMID: 37410388 PMCID: PMC10388301 DOI: 10.1021/acs.jmedchem.3c00617] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/07/2023]
Abstract
Two new 'hybrid' metallodrugs of Au(III) (AuTAML) and Cu(II) (CuTAML) were designed featuring a tamoxifen-derived pharmacophore to ideally synergize the anticancer activity of both the metal center and the organic ligand. The compounds have antiproliferative effects against human MCF-7 and MDA-MB 231 breast cancer cells. Molecular dynamics studies suggest that the compounds retain the binding activity to estrogen receptor (ERα). In vitro and in silico studies showed that the Au(III) derivative is an inhibitor of the seleno-enzyme thioredoxin reductase, while the Cu(II) complex may act as an oxidant of different intracellular thiols. In breast cancer cells treated with the compounds, a redox imbalance characterized by a decrease in total thiols and increased reactive oxygen species production was detected. Despite their different reactivities and cytotoxic potencies, a great capacity of the metal complexes to induce mitochondrial damage was observed as shown by their effects on mitochondrial respiration, membrane potential, and morphology.
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Affiliation(s)
- Valeria Scalcon
- Department of Biomedical Sciences, University of Padova, Via Ugo Bassi 58/b, 35131 Padova, Italy
| | - Riccardo Bonsignore
- Dipartimento di Scienze e Tecnologie Biologiche, Chimiche e Farmaceutiche, Università degli Studi di Palermo, Viale delle Scienze, Edificio 17, 90128 Palermo, Italy
| | - Jana Aupič
- National Research Council of Italy Institute of Materials (CNR-IOM) C/o SISSA, Via Bonomea 265, 34136 Trieste, Italy
| | - Sophie R Thomas
- Chair of Medicinal and Bioinorganic Chemistry, Department of Chemistry, School of Natural Sciences, Technical University of Munich, Lichtenbergstraße 4, D-85748 Garching bei, München, Germany
| | - Alessandra Folda
- Department of Biomedical Sciences, University of Padova, Via Ugo Bassi 58/b, 35131 Padova, Italy
| | - Alexandra A Heidecker
- Catalysis Research Center & Department of Chemistry, Chair of Inorganic and Metal-Organic Chemistry, School of Natural Sciences, Technical University of Munich, Ernst-Otto-Fischer Str. 1, D-85748 Garching bei, München, Germany
| | - Alexander Pöthig
- Catalysis Research Center & Department of Chemistry, Chair of Inorganic and Metal-Organic Chemistry, School of Natural Sciences, Technical University of Munich, Ernst-Otto-Fischer Str. 1, D-85748 Garching bei, München, Germany
| | - Alessandra Magistrato
- National Research Council of Italy Institute of Materials (CNR-IOM) C/o SISSA, Via Bonomea 265, 34136 Trieste, Italy
| | - Angela Casini
- Chair of Medicinal and Bioinorganic Chemistry, Department of Chemistry, School of Natural Sciences, Technical University of Munich, Lichtenbergstraße 4, D-85748 Garching bei, München, Germany
| | - Maria Pia Rigobello
- Department of Biomedical Sciences, University of Padova, Via Ugo Bassi 58/b, 35131 Padova, Italy
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Thomas SR, Yang W, Morgan DJ, Davies TE, Li JJ, Fischer RA, Huang J, Dimitratos N, Casini A. Bottom-up Synthesis of Water-Soluble Gold Nanoparticles Stabilized by N-Heterocyclic Carbenes: From Structural Characterization to Applications. Chemistry 2022; 28:e202201575. [PMID: 35801389 PMCID: PMC9804724 DOI: 10.1002/chem.202201575] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Indexed: 01/09/2023]
Abstract
N-heterocyclic carbenes (NHCs) have become attractive ligands for functionalizing gold nanoparticle surfaces with applications ranging from catalysis to biomedicine. Despite their great potential, NHC stabilized gold colloids (NHC@AuNPs) are still scarcely explored and further efforts should be conducted to improve their design and functionalization. Here, the 'bottom-up' synthesis of two water-soluble gold nanoparticles (AuNP-1 and AuNP-2) stabilized by hydrophilic mono- and bidentate NHC ligands is reported together with their characterization by various spectroscopic and analytical methods. The NPs showed key differences likely to be due to the selected NHC ligand systems. Transmission electron microscopy (TEM) images showed small quasi-spherical and faceted NHC@AuNPs of similar particle size (ca. 2.3-2.6 nm) and narrow particle size distribution, but the colloids featured different ratios of Au(I)/Au(0) by X-ray photoelectron spectroscopy (XPS). Furthermore, the NHC@AuNPs were supported on titania and fully characterized. The new NPs were studied for their catalytic activity towards the reduction of nitrophenol substrates, the reduction of resazurin and for their photothermal efficiency. Initial results on their application in photothermal therapy (PTT) were obtained in human cancer cells in vitro. The aforementioned reactions represent important model reactions towards wastewater remediation, bioorthogonal transformations and cancer treatment.
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Affiliation(s)
- Sophie R. Thomas
- Chair of Medicinal and Bioinorganic ChemistryDepartment of ChemistryTechnical University of MunichLichtenbergstrasse 485747GarchingGermany
| | - Wenjie Yang
- School of Chemical and Biomolecular EngineeringUniversity of SydneyNSW2006Australia
| | - David J. Morgan
- School of ChemistryCardiff UniversityMain Building, Park PlaceCardiffCF10 3ATU.K.
| | - Thomas E. Davies
- School of ChemistryCardiff UniversityMain Building, Park PlaceCardiffCF10 3ATU.K.
| | - Jiao Jiao Li
- Kolling InstituteFaculty of Medicine and HealthUniversity of SydneySt LeonardsNSW2065Australia
| | - Roland A. Fischer
- Chair of Inorganic and Metal–Organic ChemistryDepartment of ChemistryTechnical University of MunichLichtenbergstrasse 485747GarchingGermany
| | - Jun Huang
- School of Chemical and Biomolecular EngineeringUniversity of SydneyNSW2006Australia
| | - Nikolaos Dimitratos
- Department of Industrial Chemistry “Toso Montanari” Universita' degli Studi di BolognaViale Risorgimento40136BolognaItaly,Center for Chemical Catalysis - C3, Alma Mater Studiorum Università di BolognaViale Risorgimento 440136BolognaItaly
| | - Angela Casini
- Chair of Medicinal and Bioinorganic ChemistryDepartment of ChemistryTechnical University of MunichLichtenbergstrasse 485747GarchingGermany,Munich Data Science Institute (MDSI)Technical University of MunichWalther-von-Dyck Strasse 1085748GarchingGermany
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6
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Bonsignore R, Thomas SR, Rigoulet M, Jandl C, Pöthig A, Bourissou D, Barone G, Casini A. C-C Cross-Couplings from a Cyclometalated Au(III) C ∧ N Complex: Mechanistic Insights and Synthetic Developments. Chemistry 2021; 27:14322-14334. [PMID: 34310783 PMCID: PMC8597034 DOI: 10.1002/chem.202102668] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Indexed: 12/11/2022]
Abstract
In recent years, the reactivity of gold complexes was shown to extend well beyond π-activation and to hold promises to achieve selective cross-couplings in several C-C and C-E (E=heteroatom) bond forming reactions. Here, with the aim of exploiting new organometallic species for cross-coupling reactions, we report on the Au(III)-mediated C(sp2 )-C(sp) occurring upon reaction of the cyclometalated complex [Au(CCH2 N)Cl2 ] (1, CCH2 N=2-benzylpyridine) with AgPhCC. The reaction progress has been monitored by NMR spectroscopy, demonstrating the involvement of a number of key intermediates, whose structures have been unambiguously ascertained through 1D and 2D NMR analyses (1 H, 13 C, 1 H-1 H COSY, 1 H-13 C HSQC and 1 H-13 C HMBC) as well as by HR-ESI-MS and X-ray diffraction studies. Furthermore, crystallographic studies have serendipitously resulted in the authentication of zwitterionic Au(I) complexes as side-products arising from cyclization of the coupling product in the coordination sphere of gold. The experimental work has been paralleled and complemented by DFT calculations of the reaction profiles, providing valuable insight into the structure and energetics of the key intermediates and transition states, as well as on the coordination sphere of gold along the whole process. Of note, the broader scope of the cross-coupling at the Au(III) CCH2 N centre has also been demonstrated studying the reaction of 1 with C(sp2 )-based nucleophiles, namely vinyl and heteroaryl tin and zinc reagents. These reactions stand as rare examples of C(sp2 )-C(sp2 ) cross-couplings at Au(III).
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Affiliation(s)
- Riccardo Bonsignore
- Chair of Medicinal and Bioinorganic ChemistryDepartment of ChemistryTechnical University of MunichLichtenbergstr. 485748Garching b. MünchenGermany
| | - Sophie R. Thomas
- Chair of Medicinal and Bioinorganic ChemistryDepartment of ChemistryTechnical University of MunichLichtenbergstr. 485748Garching b. MünchenGermany
- School of ChemistryCardiff UniversityMain BuildingPark PlaceCF10 3ATCardiffUK
| | - Mathilde Rigoulet
- CNRS/Université Paul SabatierLaboratoire Hétérochimie Fondamentale et Appliquée (LHFA, UMR 5069)118 Route de Narbonne31062Toulouse Cedex 09France
| | - Christian Jandl
- Catalysis Research Center & Department of ChemistryTechnical University of MunichErnst-Otto-Fischer Str. 185748Garching b. MünchenGermany
| | - Alexander Pöthig
- Catalysis Research Center & Department of ChemistryTechnical University of MunichErnst-Otto-Fischer Str. 185748Garching b. MünchenGermany
| | - Didier Bourissou
- CNRS/Université Paul SabatierLaboratoire Hétérochimie Fondamentale et Appliquée (LHFA, UMR 5069)118 Route de Narbonne31062Toulouse Cedex 09France
| | - Giampaolo Barone
- Dipartimento di Scienze e Tecnologie Biologiche, Chimiche e FarmaceuticheUniversità degli Studi di PalermoViale delle Scienze, Edificio 1790128PalermoItaly
| | - Angela Casini
- Chair of Medicinal and Bioinorganic ChemistryDepartment of ChemistryTechnical University of MunichLichtenbergstr. 485748Garching b. MünchenGermany
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Casini A, Thomas SR. The Beauty of Gold: Knowledge of Mechanisms Leads to Different Applications of Organogold Compounds in Medicine and Catalysis. CHEM LETT 2021. [DOI: 10.1246/cl.210238] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Angela Casini
- Chair of Medicinal and Bioinorganic chemistry, Department of Chemistry, Technical University of Munich, Lichtenbergstr. 4, 85748 Garching, Germany
| | - Sophie R. Thomas
- Chair of Medicinal and Bioinorganic chemistry, Department of Chemistry, Technical University of Munich, Lichtenbergstr. 4, 85748 Garching, Germany
- School of Chemistry, Cardiff University, Main Building, Park Place, CF10 3AT Cardiff, United Kingdom
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Thomas SR, Bonsignore R, Sánchez Escudero J, Meier-Menches SM, Brown CM, Wolf MO, Barone G, Luk LYP, Casini A. Exploring the Chemoselectivity towards Cysteine Arylation by Cyclometallated Au III Compounds: New Mechanistic Insights. Chembiochem 2020; 21:3071-3076. [PMID: 32511840 PMCID: PMC7689846 DOI: 10.1002/cbic.202000262] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Revised: 06/05/2020] [Indexed: 12/15/2022]
Abstract
To gain more insight into the factors controlling efficient cysteine arylation by cyclometallated AuIII complexes, the reaction between selected gold compounds and different peptides was investigated by high‐resolution liquid chromatography electrospray ionization mass spectrometry (HR‐LC‐ESI‐MS). The deduced mechanisms of C−S cross‐coupling, also supported by density functional theory (DFT) and quantum mechanics/molecular mechanics (QM/MM) calculations, evidenced the key role of secondary peptidic gold binding sites in favouring the process of reductive elimination.
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Affiliation(s)
- Sophie R Thomas
- School of Chemistry, Cardiff University Main Building, Park Place, CF10 3AT, Cardiff, UK
| | - Riccardo Bonsignore
- School of Chemistry, Cardiff University Main Building, Park Place, CF10 3AT, Cardiff, UK
| | - Jorge Sánchez Escudero
- School of Chemistry, Cardiff University Main Building, Park Place, CF10 3AT, Cardiff, UK
| | - Samuel M Meier-Menches
- Department of Analytical Chemistry Faculty of Chemistry, University of Vienna, Waehringer Str. 38, 1090, Vienna, Austria
| | - Christopher M Brown
- Department of Chemistry, University of British Columbia, 2036 Main Mall, V6T 1Z1, Vancouver, BC, Canada
| | - Michael O Wolf
- Department of Chemistry, University of British Columbia, 2036 Main Mall, V6T 1Z1, Vancouver, BC, Canada
| | - Giampaolo Barone
- Dipartimento di Scienze e Tecnologie Biologiche, Chimiche e Farmaceutiche, Università degli Studi di Palermo, Viale delle Scienze, Edificio 17, 90128, Palermo, Italy
| | - Louis Y P Luk
- School of Chemistry, Cardiff University Main Building, Park Place, CF10 3AT, Cardiff, UK
| | - Angela Casini
- Department of Chemistry, Technical University of Munich, Lichtenbergstrasse 4, 85747, Garching, Germany
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Bonsignore R, Thomas SR, Klooster WT, Coles SJ, Jenkins RL, Bourissou D, Barone G, Casini A. Carbon-Phosphorus Coupling from C^N Cyclometalated Au III Complexes. Chemistry 2020; 26:4226-4231. [PMID: 31994237 PMCID: PMC7187188 DOI: 10.1002/chem.201905392] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2019] [Revised: 01/10/2020] [Indexed: 12/20/2022]
Abstract
With the aim of exploiting new organometallic species for cross-coupling reactions, we report here on the AuIII -mediated Caryl -P bond formation occurring upon reaction of C^N cyclometalated AuIII complexes with phosphines. The [Au(C^N)Cl2 ] complex 1 featuring the bidentate 2-benzoylpyridine (CCO N) scaffold was found to react with PTA (1,3,5-triaza-7-phosphaadamantane) under mild conditions, including in water, to afford the corresponding phosphonium 5 through C-P reductive elimination. A mechanism is proposed for the title reaction based on in situ 31 P{1 H} NMR and HR-ESI-MS analyses combined with DFT calculations. The C-P coupling has been generalized to other C^N cyclometalated AuIII complexes and other tertiary phosphines. Overall, this work provides new insights into the reactivity of cyclometalated AuIII compounds and establishes initial structure-activity relationships to develop AuIII -mediated C-P cross-coupling reactions.
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Affiliation(s)
- Riccardo Bonsignore
- School of ChemistryCardiff UniversityMain Building, Park PlaceCF10 3ATCardiffUK
| | - Sophie R. Thomas
- School of ChemistryCardiff UniversityMain Building, Park PlaceCF10 3ATCardiffUK
| | - Wim T. Klooster
- School of ChemistryUniversity of SouthamptonSouthamptonSO17 1BJUK
| | - Simon J. Coles
- School of ChemistryUniversity of SouthamptonSouthamptonSO17 1BJUK
| | - Robert L. Jenkins
- School of ChemistryCardiff UniversityMain Building, Park PlaceCF10 3ATCardiffUK
| | - Didier Bourissou
- CNRS/Université Paul SabatierLaboratoire Hétérochimie Fondamentale et Appliquée (LHFA, UMR 5069)118 Route de Narbonne31062Toulouse Cedex 09France
| | - Giampaolo Barone
- Dipartimento di Scienze e Tecnologie Biologiche, Chimiche e FarmaceuticheUniversità degli Studi di PalermoViale delle Scienze, Edificio 1790128PalermoItaly
| | - Angela Casini
- School of ChemistryCardiff UniversityMain Building, Park PlaceCF10 3ATCardiffUK
- Department of ChemistryTechnical University of MunichLichtenbergstr. 485747GarchingGermany
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Affiliation(s)
- Emma Freeman
- Department of Chemical Engineering University of Bath Claverton Down Bath BA2 7AY UK
- EPSRC Centre for Doctoral Training in Catalysis School of Chemistry Cardiff University Park Place Cardiff CF10 3AT UK
| | - Santosh Kumar
- Department of Chemical Engineering University of Bath Claverton Down Bath BA2 7AY UK
- Department of Chemical Engineering Imperial College London South Kensington, London SW7 2AZ UK
| | - Sophie R. Thomas
- Department of Chemical Engineering University of Bath Claverton Down Bath BA2 7AY UK
- EPSRC Centre for Doctoral Training in Catalysis School of Chemistry Cardiff University Park Place Cardiff CF10 3AT UK
| | - Hayley Pickering
- Department of Chemical Engineering University of Bath Claverton Down Bath BA2 7AY UK
| | - David J. Fermin
- School of Chemistry University of Bristol Cantock's close Bristol BS8 1TS UK
| | - Salvador Eslava
- Department of Chemical Engineering University of Bath Claverton Down Bath BA2 7AY UK
- Department of Chemical Engineering Imperial College London South Kensington, London SW7 2AZ UK
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Wenzel MN, Bonsignore R, Thomas SR, Bourissou D, Barone G, Casini A. Cyclometalated Au III Complexes for Cysteine Arylation in Zinc Finger Protein Domains: towards Controlled Reductive Elimination. Chemistry 2019; 25:7628-7634. [PMID: 30990916 PMCID: PMC6594228 DOI: 10.1002/chem.201901535] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Indexed: 12/14/2022]
Abstract
With the aim of exploiting the use of organometallic species for the efficient modification of proteins through C‐atom transfer, the gold‐mediated cysteine arylation through a reductive elimination process occurring from the reaction of cyclometalated AuIII C^N complexes with a zinc finger peptide (Cys2His2 type) is here reported. Among the four selected AuIII cyclometalated compounds, the [Au(CCON)Cl2] complex featuring the 2‐benzoylpyridine (CCON) scaffold was identified as the most prone to reductive elimination and Cys arylation in buffered aqueous solution (pH 7.4) at 37 °C by high‐resolution LC electrospray ionization mass spectrometry. DFT and quantum mechanics/molecular mechanics (QM/MM) studies permitted to propose a mechanism for the title reaction that is in line with the experimental results. Overall, the results provide new insights into the reactivity of cytotoxic organogold compounds with biologically important zinc finger domains and identify initial structure–activity relationships to enable AuIII‐catalyzed reductive elimination in aqueous media.
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Affiliation(s)
- Margot N Wenzel
- School of Chemistry, Cardiff University, Main Building, Park Place, CF10 3AT, Cardiff, UK
| | - Riccardo Bonsignore
- School of Chemistry, Cardiff University, Main Building, Park Place, CF10 3AT, Cardiff, UK
| | - Sophie R Thomas
- School of Chemistry, Cardiff University, Main Building, Park Place, CF10 3AT, Cardiff, UK
| | - Didier Bourissou
- CNRS/Université Paul Sabatier, Laboratoire Hétérochimie Fondamentale et Appliquée (LHFA, UMR 5069), 118 Route de Narbonne, 31062, Toulouse Cedex 09, France
| | - Giampaolo Barone
- Dipartimento di Scienze e Tecnologie Biologiche, Chimiche e Farmaceutiche, Università di Palermo, Viale delle Scienze, Edificio 17, 90128, Palermo, Italy
| | - Angela Casini
- School of Chemistry, Cardiff University, Main Building, Park Place, CF10 3AT, Cardiff, UK
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Woods B, Wenzel MN, Williams T, Thomas SR, Jenkins RL, Casini A. Exo-Functionalized Metallacages as Host-Guest Systems for the Anticancer Drug Cisplatin. Front Chem 2019; 7:68. [PMID: 30834242 PMCID: PMC6387950 DOI: 10.3389/fchem.2019.00068] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2018] [Accepted: 01/24/2019] [Indexed: 12/19/2022] Open
Abstract
Within the framework of designing new self-assembled metallosupramolecular architectures for drug delivery, seven [Pd2L4]4+ metallacages (L = 2,6-bis(pyridine-3-ylethynyl)pyridine) featuring different groups in exo-position, selected to enhance the cage solubility in aqueous environment, were synthesized. Thus, carboxylic acids, sugars, and PEG groups were tethered to the bispyridyl ligands directly or via disulfide bond formation, as well as via click chemistry. The ligands and respective cages were characterized by different methods, including NMR spectroscopy and high-resolution electrospray mass spectrometry (HR-ESI-MS). While the two ligands featuring carboxylic acid-functionalized groups showed improved solubility in water, the other ligands were soluble only in organic solvents. Unfortunately, all the respective self-assembled cages were also insoluble in water. Afterwards, the encapsulation properties of the anticancer drug cisplatin in selected [Pd2L4]X4 cages (X =NO 3 - ,BF 4 - ) were studied by 1H, 1H DOSY, and 195Pt NMR spectroscopy. The effect of the counter ions as well as of the polarity of the solvent in the drug encapsulation process were also investigated, and provided useful information on the host-guest properties of these experimental drug delivery systems. Our results provide further experimental support for previous studies that suggest the desolvation of guests from surrounding solvent molecules and the resulting solvent rearrangement may actually be the primary driving force for determining guest binding affinities in metallacages, in the absence of specific functional group interactions.
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Affiliation(s)
| | | | | | | | | | - Angela Casini
- School of Chemistry, Cardiff University, Cardiff, United Kingdom
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Wenzel MN, Mósca AF, Graziani V, Aikman B, Thomas SR, de Almeida A, Platts JA, Re N, Coletti C, Marrone A, Soveral G, Casini A. Insights into the Mechanisms of Aquaporin-3 Inhibition by Gold(III) Complexes: the Importance of Non-Coordinative Adduct Formation. Inorg Chem 2019; 58:2140-2148. [DOI: 10.1021/acs.inorgchem.8b03233] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Margot N. Wenzel
- School of Chemistry, Cardiff University, Main Building, Park Place, CF10 3AT Cardiff, United Kingdom
| | - Andreia F. Mósca
- Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy, Universidade de Lisboa, 1649-003 Lisboa, Portugal
| | - Valentina Graziani
- Università“G. d’Annunzio” di Chieti-Pescara, Department of Pharmacy, Via dei Vestini 31, 66100 Chieti, Italy
| | - Brech Aikman
- School of Chemistry, Cardiff University, Main Building, Park Place, CF10 3AT Cardiff, United Kingdom
| | - Sophie R. Thomas
- School of Chemistry, Cardiff University, Main Building, Park Place, CF10 3AT Cardiff, United Kingdom
| | - Andreia de Almeida
- School of Chemistry, Cardiff University, Main Building, Park Place, CF10 3AT Cardiff, United Kingdom
- Tumour Microenvironment Group, Division of Cancer and Genetics, School of Medicine, Cardiff University, Tenovus Building, Cardiff CF14 4XN, United Kingdom
| | - James A. Platts
- School of Chemistry, Cardiff University, Main Building, Park Place, CF10 3AT Cardiff, United Kingdom
| | - Nazzareno Re
- Università“G. d’Annunzio” di Chieti-Pescara, Department of Pharmacy, Via dei Vestini 31, 66100 Chieti, Italy
| | - Cecilia Coletti
- Università“G. d’Annunzio” di Chieti-Pescara, Department of Pharmacy, Via dei Vestini 31, 66100 Chieti, Italy
| | - Alessandro Marrone
- Università“G. d’Annunzio” di Chieti-Pescara, Department of Pharmacy, Via dei Vestini 31, 66100 Chieti, Italy
| | - Graça Soveral
- Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy, Universidade de Lisboa, 1649-003 Lisboa, Portugal
| | - Angela Casini
- School of Chemistry, Cardiff University, Main Building, Park Place, CF10 3AT Cardiff, United Kingdom
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Zhou J, Shi MX, Mitchell TD, Smagin GN, Thomas SR, Ryan DH, Harris RB. Changes in Rat Adipocyte and Liver Glucose Metabolism Following Repeated Restraint Stress. Exp Biol Med (Maywood) 2016; 226:312-9. [PMID: 11368423 DOI: 10.1177/153537020122600408] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Rats exposed to repeated restraint weigh less than controls even 8 weeks after stress. Stress-induced weight loss is lean tissue, but the post-stress difference in weight between control and restrained rats is lean and fat mass. Whole-body glucose clearance is enhanced 1 day after stress, but adipocyte glucose utilization is inhibited and muscle glucose transport is unchanged. The studies described here demonstrated that glucose transport was increased in both restrained and pair-fed rats, but that glycogen synthesis was increased only in restrained rats, which may account for the improved whole-body glucose clearance. Adipocyte glucose transport was inhibited and adipose plasma membrane β-adrenergic receptor number was increased 1 day post-stress in restrained rats when weight loss was lean tissue, but were not different from control rats 5 days post-stress, when both fat and lean tissue were reduced. Thus, repeated restraint induces reversible changes in adipocyte metabolism that may represent a transition from the catabolic state of stress to a new energetic equilibrium in rats that maintain a reduced body weight for an extended period of time.
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Affiliation(s)
- J Zhou
- Pennington Biomedical Research Center, Louisiana State University, Baton Rouge 70808, USA.
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Huang Y, Thoms JAI, Tursky ML, Knezevic K, Beck D, Chandrakanthan V, Suryani S, Olivier J, Boulton A, Glaros EN, Thomas SR, Lock RB, MacKenzie KL, Bushweller JH, Wong JWH, Pimanda JE. MAPK/ERK2 phosphorylates ERG at serine 283 in leukemic cells and promotes stem cell signatures and cell proliferation. Leukemia 2016; 30:1552-61. [PMID: 27055868 DOI: 10.1038/leu.2016.55] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2015] [Revised: 12/23/2015] [Accepted: 02/02/2016] [Indexed: 12/19/2022]
Abstract
Aberrant ERG (v-ets avian erythroblastosis virus E26 oncogene homolog) expression drives leukemic transformation in mice and high expression is associated with poor patient outcomes in acute myeloid leukemia (AML) and T-acute lymphoblastic leukemia (T-ALL). Protein phosphorylation regulates the activity of many ETS factors but little is known about ERG in leukemic cells. To characterize ERG phosphorylation in leukemic cells, we applied liquid chromatography coupled tandem mass spectrometry and identified five phosphorylated serines on endogenous ERG in T-ALL and AML cells. S283 was distinct as it was abundantly phosphorylated in leukemic cells but not in healthy hematopoietic stem and progenitor cells (HSPCs). Overexpression of a phosphoactive mutant (S283D) increased expansion and clonogenicity of primary HSPCs over and above wild-type ERG. Using a custom antibody, we screened a panel of primary leukemic xenografts and showed that ERG S283 phosphorylation was mediated by mitogen-activated protein kinase/extracellular signal-regulated kinase (MAPK/ERK) signaling and in turn regulated expression of components of this pathway. S283 phosphorylation facilitates ERG enrichment and transactivation at the ERG +85 HSPC enhancer that is active in AML and T-ALL with poor prognosis. Taken together, we have identified a specific post-translational modification in leukemic cells that promotes progenitor proliferation and is a potential target to modulate ERG-driven transcriptional programs in leukemia.
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Affiliation(s)
- Y Huang
- Adult Cancer Program, Prince of Wales Clinical School, Lowy Cancer Research Centre, UNSW Australia, Sydney, New South Wales, Australia
| | - J A I Thoms
- Adult Cancer Program, Prince of Wales Clinical School, Lowy Cancer Research Centre, UNSW Australia, Sydney, New South Wales, Australia
| | - M L Tursky
- Adult Cancer Program, Prince of Wales Clinical School, Lowy Cancer Research Centre, UNSW Australia, Sydney, New South Wales, Australia.,Children's Cancer Institute Australia, Lowy Cancer Research Centre, UNSW Australia, Sydney, New South Wales, Australia
| | - K Knezevic
- Adult Cancer Program, Prince of Wales Clinical School, Lowy Cancer Research Centre, UNSW Australia, Sydney, New South Wales, Australia
| | - D Beck
- Adult Cancer Program, Prince of Wales Clinical School, Lowy Cancer Research Centre, UNSW Australia, Sydney, New South Wales, Australia
| | - V Chandrakanthan
- Adult Cancer Program, Prince of Wales Clinical School, Lowy Cancer Research Centre, UNSW Australia, Sydney, New South Wales, Australia
| | - S Suryani
- Children's Cancer Institute Australia, Lowy Cancer Research Centre, UNSW Australia, Sydney, New South Wales, Australia
| | - J Olivier
- School of Mathematics and Statistics, UNSW Australia, Sydney, New South Wales, Australia
| | - A Boulton
- Department of Chemistry, University of Virginia, Charlottesville, VA, USA
| | - E N Glaros
- School of Medical Sciences, UNSW Australia, Sydney, New South Wales, Australia
| | - S R Thomas
- School of Medical Sciences, UNSW Australia, Sydney, New South Wales, Australia
| | - R B Lock
- Children's Cancer Institute Australia, Lowy Cancer Research Centre, UNSW Australia, Sydney, New South Wales, Australia
| | - K L MacKenzie
- Children's Cancer Institute Australia, Lowy Cancer Research Centre, UNSW Australia, Sydney, New South Wales, Australia
| | - J H Bushweller
- Department of Chemistry, University of Virginia, Charlottesville, VA, USA
| | - J W H Wong
- Adult Cancer Program, Prince of Wales Clinical School, Lowy Cancer Research Centre, UNSW Australia, Sydney, New South Wales, Australia
| | - J E Pimanda
- Adult Cancer Program, Prince of Wales Clinical School, Lowy Cancer Research Centre, UNSW Australia, Sydney, New South Wales, Australia.,Department of Hematology, Prince of Wales Hospital, Sydney, New South Wales, Australia
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Thomas JMF, Thomas SR. P183 Mesothelioma in rural Scotland: a review of 5 years of experience. Thorax 2015. [DOI: 10.1136/thoraxjnl-2015-207770.320] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Moody SE, Schinzel AC, Singh S, Izzo F, Strickland MR, Luo L, Thomas SR, Boehm JS, Kim SY, Wang ZC, Hahn WC. PRKACA mediates resistance to HER2-targeted therapy in breast cancer cells and restores anti-apoptotic signaling. Oncogene 2014; 34:2061-71. [PMID: 24909179 PMCID: PMC4261061 DOI: 10.1038/onc.2014.153] [Citation(s) in RCA: 73] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2014] [Revised: 04/12/2014] [Accepted: 04/18/2014] [Indexed: 12/19/2022]
Abstract
Targeting HER2 with antibodies or small molecule inhibitors in HER2-positive breast cancer leads to improved survival, but resistance is a common clinical problem. To uncover novel mechanisms of resistance to anti-HER2 therapy in breast cancer, we performed a kinase open reading frame screen to identify genes that rescue HER2-amplified breast cancer cells from HER2 inhibition or suppression. In addition to multiple members of the MAPK (mitogen-activated protein kinase) and PI3K (phosphoinositide 3-kinase) signaling pathways, we discovered that expression of the survival kinases PRKACA and PIM1 rescued cells from anti-HER2 therapy. Furthermore, we observed elevated PRKACA expression in trastuzumab-resistant breast cancer samples, indicating that this pathway is activated in breast cancers that are clinically resistant to trastuzumab-containing therapy. We found that neither PRKACA nor PIM1 restored MAPK or PI3K activation after lapatinib or trastuzumab treatment, but rather inactivated the pro-apoptotic protein BAD, the BCl-2-associated death promoter, thereby permitting survival signaling through BCL-XL. Pharmacological blockade of BCL-XL/BCL-2 partially abrogated the rescue effects conferred by PRKACA and PIM1, and sensitized cells to lapatinib treatment. These observations suggest that combined targeting of HER2 and the BCL-XL/BCL-2 anti-apoptotic pathway may increase responses to anti-HER2 therapy in breast cancer and decrease the emergence of resistant disease.
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Affiliation(s)
- S E Moody
- 1] Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, USA [2] Department of Medicine, Bringham and Women's Hospital and Harvard Medical School, Boston, MA, USA [3] Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - A C Schinzel
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, USA
| | - S Singh
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, USA
| | - F Izzo
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, USA
| | - M R Strickland
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, USA
| | - L Luo
- 1] Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, USA [2] Department of Medicine, Bringham and Women's Hospital and Harvard Medical School, Boston, MA, USA
| | - S R Thomas
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - J S Boehm
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - S Y Kim
- Department of Molecular Genetics and Microbiology, Duke University, Durham, NC, USA
| | - Z C Wang
- 1] Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA, USA [2] Department of Surgery, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA
| | - W C Hahn
- 1] Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, USA [2] Department of Medicine, Bringham and Women's Hospital and Harvard Medical School, Boston, MA, USA [3] Broad Institute of MIT and Harvard, Cambridge, MA, USA
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Moody SE, Schinzel AC, Singh S, Izzo F, Strickland MR, Luo LY, Thomas SR, Boehm JS, Kim SY, Wang ZC, Hahn WC. Abstract P5-08-01: Systematic interrogation of resistance to HER2-directed therapy identifies a survival pathway activated by PRKACA and PIM1. Cancer Res 2013. [DOI: 10.1158/0008-5472.sabcs13-p5-08-01] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Abstract
Amplification and/or overexpression of the receptor tyrosine kinase HER2 occurs in 20-25% of breast cancers, and is associated with poor prognosis. Targeting of HER2 with drugs such as trastuzumab, lapatinib, or pertuzumab has led to clinical benefit in patients with both metastatic and early-stage HER2-amplified breast cancer. However, resistance and disease progression always occurs in patients with metastatic disease, and many patients with early-stage breast cancer experience recurrences despite adjuvant anti-HER2 therapy. As such, understanding the mechanisms of resistance to anti-HER2 therapy has important clinical implications.
Recent studies have identified mutations in PIK3CA, the gene encoding the catalytic subunit of Phosphatidylinositol 3 kinase (PI3K), as one mechanism of resistance to trastuzumab. However, such mutations are present in only a fraction of trastuzumab-resistant breast cancers. We therefore sought to uncover novel mechanisms of resistance to anti-HER2 therapy through an unbiased screen for kinases and kinase-related molecules that are able to rescue HER2-amplified breast cancer cells from HER2 inhibition.
We utilized a library of nearly 600 lentivirally-delivered open reading frames (ORFs) to constitutively express the coding sequence of each molecule individually in HER2-amplified BT474 breast cancer cells in arrayed high-throughput format. We conducted two parallel screens for the ability of each of these molecules to rescue cells from anti-HER2 therapy: one in which we treated the cells with a lapatinib-like drug that inhibits the kinase activity of HER2 and EGFR, and one in which we lentivirally delivered a short hairpin RNA that suppresses expression of HER2.
We identified those ORFs that restored viability of BT474 cells to greater than two standard deviations above the median of all ORFs in each screen. Multiple members of the MAPK and PI3K signaling pathways scored in both screens, serving to validate the approach. In addition, the survival kinases PIM1 and PRKACA scored robustly. Mechanistic studies suggest that these kinases may confer resistance by restoring the phosphorylation of, and thereby inactivating, the pro-apoptotic protein BAD. Consistent with this finding, overexpression of Bcl-xl, which is inhibited by BAD, also conferred resistance to lapatinib in HER2-amplified breast cancer cells. Furthermore, pharmacological blockade of Bcl-xl and Bcl-2 with ABT-263 enhanced lapatinib-induced killing of HER2-amplified breast cancer cells in vitro, and partially abrogated the rescue conferred by both PRKACA and PIM1. These findings suggest that combined inhibition of HER2 and the anti-apoptotic molecules Bcl-xl and Bcl-2 could enhance tumor cell eradication and prevent or delay the emergence of resistant disease.
Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P5-08-01.
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Affiliation(s)
- SE Moody
- Dana-Farber Cancer Institute, Boston, MA; Broad Institute, Cambridge, MA; Duke University, Durham, NC; Brigham and Women's Hospital and Harvard Medical School, Boston, MA
| | - AC Schinzel
- Dana-Farber Cancer Institute, Boston, MA; Broad Institute, Cambridge, MA; Duke University, Durham, NC; Brigham and Women's Hospital and Harvard Medical School, Boston, MA
| | - S Singh
- Dana-Farber Cancer Institute, Boston, MA; Broad Institute, Cambridge, MA; Duke University, Durham, NC; Brigham and Women's Hospital and Harvard Medical School, Boston, MA
| | - F Izzo
- Dana-Farber Cancer Institute, Boston, MA; Broad Institute, Cambridge, MA; Duke University, Durham, NC; Brigham and Women's Hospital and Harvard Medical School, Boston, MA
| | - MR Strickland
- Dana-Farber Cancer Institute, Boston, MA; Broad Institute, Cambridge, MA; Duke University, Durham, NC; Brigham and Women's Hospital and Harvard Medical School, Boston, MA
| | - LY Luo
- Dana-Farber Cancer Institute, Boston, MA; Broad Institute, Cambridge, MA; Duke University, Durham, NC; Brigham and Women's Hospital and Harvard Medical School, Boston, MA
| | - SR Thomas
- Dana-Farber Cancer Institute, Boston, MA; Broad Institute, Cambridge, MA; Duke University, Durham, NC; Brigham and Women's Hospital and Harvard Medical School, Boston, MA
| | - JS Boehm
- Dana-Farber Cancer Institute, Boston, MA; Broad Institute, Cambridge, MA; Duke University, Durham, NC; Brigham and Women's Hospital and Harvard Medical School, Boston, MA
| | - SY Kim
- Dana-Farber Cancer Institute, Boston, MA; Broad Institute, Cambridge, MA; Duke University, Durham, NC; Brigham and Women's Hospital and Harvard Medical School, Boston, MA
| | - ZC Wang
- Dana-Farber Cancer Institute, Boston, MA; Broad Institute, Cambridge, MA; Duke University, Durham, NC; Brigham and Women's Hospital and Harvard Medical School, Boston, MA
| | - WC Hahn
- Dana-Farber Cancer Institute, Boston, MA; Broad Institute, Cambridge, MA; Duke University, Durham, NC; Brigham and Women's Hospital and Harvard Medical School, Boston, MA
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Guiney WJ, Beaumont C, Thomas SR. Use of the entero-test, a novel approach for the noninvasive capture of biliary metabolites in dogs. Drug Metab Dispos 2010; 38:851-6. [PMID: 20110404 DOI: 10.1124/dmd.109.031062] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Preclinical information on the biliary metabolites of a drug candidate is typically obtained through the collection of bile after surgical cannulation of the bile duct. In this study, we describe a novel approach using the Entero-Test, a simple device that facilitates the noninvasive sampling of duodenal bile. The Entero-Test was used to collect bile from six fasted dogs that had been dosed either orally with simvastatin (SV) or intravenously with simvastatin hydroxy acid (SVA), compounds that have been previously reported to undergo extensive metabolism and biliary secretion in the dog. The devices, consisting of a weighted gelatin capsule containing 90 cm of a highly absorbent nylon string, were swallowed by each dog with the proximal end of the string taped to the animal's face. Once the weighted string had reached the duodenum, gallbladder contraction was stimulated to release bile. Each bile-stained string was then retrieved via the mouth and, after solvent extraction, samples were analyzed for drug-related material by ultraperformance liquid chromatography-mass spectrometry and NMR spectroscopy. Numerous metabolites of SV and SVA were observed, and, in general, the major metabolites have been reported previously from studies with bile duct-cannulated animals dosed with [14C]SV or [14C]SVA. The results from this study demonstrate the utility of deploying the Entero-Test in absorption, distribution, metabolism, and elimination studies to provide information on the nature of biliary metabolites, which, on occasion, may be sufficient to negate the need for more invasive sampling techniques. The benefits and limitations of the technique are discussed.
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Affiliation(s)
- W J Guiney
- Toxicokinetics and Biotransformation, PCD DMPK Department, GlaxoSmithKline, Park Road, Ware, Hertfordshire SG120DP, UK.
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Fenner JW, Brook B, Clapworthy G, Coveney PV, Feipel V, Gregersen H, Hose DR, Kohl P, Lawford P, McCormack KM, Pinney D, Thomas SR, Van Sint Jan S, Waters S, Viceconti M. The EuroPhysiome, STEP and a roadmap for the virtual physiological human. Philos Trans A Math Phys Eng Sci 2008; 366:2979-99. [PMID: 18559316 DOI: 10.1098/rsta.2008.0089] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Biomedical science and its allied disciplines are entering a new era in which computational methods and technologies are poised to play a prevalent role in supporting collaborative investigation of the human body. Within Europe, this has its focus in the virtual physiological human (VPH), which is an evolving entity that has emerged from the EuroPhysiome initiative and the strategy for the EuroPhysiome (STEP) consortium. The VPH is intended to be a solution to common infrastructure needs for physiome projects across the globe, providing a unifying architecture that facilitates integration and prediction, ultimately creating a framework capable of describing Homo sapiens in silico. The routine reliance of the biomedical industry, biomedical research and clinical practice on information technology (IT) highlights the importance of a tailor-made and robust IT infrastructure, but numerous challenges need to be addressed if the VPH is to become a mature technological reality. Appropriate investment will reap considerable rewards, since it is anticipated that the VPH will influence all sectors of society, with implications predominantly for improved healthcare, improved competitiveness in industry and greater understanding of (patho)physiological processes. This paper considers issues pertinent to the development of the VPH, highlighted by the work of the STEP consortium.
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Affiliation(s)
- J W Fenner
- Department of Medical Physics and Clinical Engineering, University of Sheffield, I Floor, Royal Hallamshire Hospital, Glossop Road, Sheffield S10 2JF, UK.
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Dzodic V, Hervy S, Fritsch D, Khalfallah H, Thereau M, Thomas SR. Web-based tools for quantitative renal physiology. Cell Mol Biol (Noisy-le-grand) 2004; 50:795-800. [PMID: 15672462] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/01/2023]
Abstract
We present the development strategy and present state of progress on an interactive website project for quantitative renal physiology: a) a quantitative kidney database (QKDB), and b) an interactive website presenting mathematical models covering the major aspects of renal physiology. QKDB will house data for quantitative evaluation of hypotheses of renal function, from the cellular, through the epithelial and tubular, to whole organ levels. It will thus facilitate comparisons among different species and under various experimental conditions. It will include especially: transport parameters, tubular concentrations and flow rates along the various nephron segments, and anatomical details, in human kidneys, in experimentally studied species, and in model epithelia, such as cultured cells and amphibian skin and urinary bladder. The modeling resource will provide an interactive user interface to a collection of published models at all levels of renal physiology, enabling non-modelers to exploit the models, altering key parameters according to hypotheses of their own and visualizing the simulation results, thus permitting quantitative exploration of new hypotheses. Implementation will be facilitated by translation of the models into a common markup language such as CellML (cell markup language) and SBML (systems biology markup language). There will thus be a modular separation of model descriptions from their numerical solution methods.
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Affiliation(s)
- V Dzodic
- INSERM U.467, Necker Faculty of Medicine, Univ. Paris 5, 156 rue de Vaugirard, 75730 Paris 15, France
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Abstract
Cemented titanium stems in hip arthroplasty are associated with proximal cement-stem debonding and early failure. This was well publicised with the 3M Capital hip. However, corrosion in this setting has been reported with only one stem design and is less widely accepted. We present a series of 12 cemented titanium Furlong Straight Stems which required revision at a mean of 78 months for thigh pain. At revision the stems were severely corroded in a pattern which was typical of crevice corrosion. Symptoms were eliminated after revision to an all-stainless steel femoral prosthesis of the same design. We discuss the likely causes for the corrosion. The combination of a titanium stem and cement appears to facilitate crevice corrosion.
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Affiliation(s)
- S R Thomas
- Kettering General Hospital, Northants, England
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Abstract
The case history of a patient with CF admitted to an ICU is presented and the appropriateness of intensive care management for patients with CF is discussed. Issues relevant to the ICU care of patients with CF are highlighted.
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Affiliation(s)
- S R Thomas
- Department of Respiratory Medicine, St George's Hospital, London, UK.
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Abstract
The mechanism by which the mammalian kidney creates the osmotic gradient necessary for urine concentration remains an open question. We present a brief survey of the give-and-take between theory and experiment on this question over the last half century. We start with the introduction of the countercurrent multiplier paradigm in 1951. We finish with a description of a recent suggestion that the explanation for the enigmatic inner medullary osmotic gradient may reside in the very metabolism of the inner medullary cells, which are required by the region's hypoxia to obtain their ATP largely from anaerobic glycolysis and which thus, by the same token, furnish net osmoles to the medullary interstitium by converting glucose to lactate.
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Affiliation(s)
- S R Thomas
- INSERM U.467, Necker Faculty of Medicine, Paris, France.
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McCarron MO, Tyagi A, Thomas SR, Sweeney BJ, Bone I. Non-convulsive status epilepticus of frontal origin following surgery for craniopharyngioma. Eur J Neurol 2002; 9:178-9. [PMID: 11882061 DOI: 10.1046/j.1468-1331.2002.0354b.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Thomas SR, Salahifar H, Mashima R, Hunt NH, Richardson DR, Stocker R. Antioxidants inhibit indoleamine 2,3-dioxygenase in IFN-gamma-activated human macrophages: posttranslational regulation by pyrrolidine dithiocarbamate. J Immunol 2001; 166:6332-40. [PMID: 11342657 DOI: 10.4049/jimmunol.166.10.6332] [Citation(s) in RCA: 93] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Induction of the heme-containing indoleamine 2,3-dioxygenase (IDO) by IFN-gamma is implicated in anti-microbial and pro-inflammatory activities of human macrophages. Antioxidants can modulate the expression of immune and inflammatory genes, and pyrrolidine dithiocarbamate (PDTC) is a frequently used antioxidant to inhibit the transcription factor NF-kappaB. Here we show that IFN-gamma treatment of human monocyte-derived macrophages (hMDMs) increased the proportion of oxidized glutathione. PDTC attenuated this increase and inhibited IDO activity, although it increased IDO protein expression and did not affect IDO mRNA expression and enzyme activity directly. Other antioxidants, 2-ME, ebselen, and t-butyl hydroquinone, inhibited IDO protein expression. Similar to PDTC, the heme biosynthesis inhibitor succinylacetone (SA) and the iron-chelator pyridoxal isonicotinoyl hydrazone inhibited cellular IDO activity without affecting protein expression, whereas addition of hemin or the heme precursor delta-aminolevulinic acid increased IDO activity. Also, incubation of IFN-gamma-activated hMDM with delta-[(14)C]-aminolevulinic acid resulted in the incorporation of label into immunoprecipitated IDO, a process inhibited by PDTC and SA. Furthermore, supplementation of lysates from PDTC- or SA-treated hMDM with hemin fully restored IDO activity to control levels, and hemin also reversed the inhibitory action of SA but not PDTC in intact cells. Together these results establish a requirement for de novo heme synthesis for IDO activity in IFN-gamma-activated hMDM. They show that, similar to other pro-inflammatory proteins, the activity of IDO is modulated by antioxidants though in the case of PDTC this takes place posttranslationally, in part by limiting the availability of heme for the formation of holo-IDO.
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Affiliation(s)
- S R Thomas
- Biochemistry and Iron Groups, The Heart Research Institute, Camperdown, New South Wales, Australia.
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Thomas SR, Perkins JM, Magee TR, Galland RB. Transmetatarsal amputation: an 8-year experience. Ann R Coll Surg Engl 2001; 83:164-6. [PMID: 11432132 PMCID: PMC2503581] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/20/2023] Open
Abstract
This study retrospectively reviews an 8-year consecutive series of transmetatarsal amputation (TMA) for forefoot ischaemia in diabetic and non-diabetic patients. Forty-one patients had TMA. Peri-operative mortality was 17% (7/41). A healed stump was achieved in 19 patients (46%) and 18 of these patients were independently mobile, or mobile with sticks. Non-diabetic patients (8/12) healed significantly better than diabetics (11/29). Median time to healing was 7 months (range 3-20 months). All non-healed survivors had a higher amputation (14 below-knee, 1 Syme's). A healed TMA gives good mobility, but prediction of who will heal after operation is unreliable. Time to healing is often lengthy, and failed healing results in higher amputation. These issues need to be fully discussed with the patient who is considered for TMA.
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Affiliation(s)
- S R Thomas
- Department of Surgery, Royal Berkshire Hospital, London Road, Reading RG1 5AN, UK
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Thomas SR, Leichtweis SB, Pettersson K, Croft KD, Mori TA, Brown AJ, Stocker R. Dietary cosupplementation with vitamin E and coenzyme Q(10) inhibits atherosclerosis in apolipoprotein E gene knockout mice. Arterioscler Thromb Vasc Biol 2001; 21:585-93. [PMID: 11304477 DOI: 10.1161/01.atv.21.4.585] [Citation(s) in RCA: 90] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Intimal oxidation of LDL is considered an important early event in atherogenesis, and certain antioxidants are antiatherogenic. Dietary coenrichment with vitamin E (VitE) plus ubiquinone-10 (CoQ(10), which is reduced during intestinal uptake to the antioxidant ubiquinol-10, CoQ(10)H(2)) protects, whereas enrichment with VitE alone can increase oxidizability of LDL lipid against ex vivo oxidation. In the present study, we tested whether VitE plus CoQ(10) cosupplementation is more antiatherogenic than either antioxidant alone, by use of apolipoprotein E-deficient (apoE-/-) mice fed a high-fat diet without (control) or with 0.2% (wt/wt) VitE, 0.5% CoQ(10), or 0.2% VitE plus 0.5% CoQ(10) (VitE+CoQ(10)) for 24 weeks. None of the supplements affected plasma cholesterol concentrations, whereas in the VitE and CoQ(10) groups, plasma level of the respective supplement increased. Compared with control, plasma from CoQ(10) or VitE+CoQ(10) but not VitE-supplemented animals was more resistant to ex vivo lipid peroxidation induced by peroxyl radicals. VitE supplementation increased VitE levels in aorta, heart, brain, and skeletal muscle, whereas CoQ(10) supplementation increased CoQ(10) only in plasma and aorta and lowered tissue VITE: All treatments significantly lowered aortic cholesterol compared with control, but only VitE+CoQ(10) supplementation significantly decreased tissue lipid hydroperoxides when expressed per parent lipid. In contrast, none of the treatments affected aortic ratios of 7-ketocholesterol to cholesterol. Compared with controls, VitE+CoQ(10) supplementation decreased atherosclerosis at the aortic root and arch and descending thoracic aorta to an extent that increased with increasing distance from the aortic root. CoQ(10) significantly inhibited atherosclerosis at aortic root and arch, whereas VitE decreased disease at aortic root only. Thus, in apoE-/- mice, VitE+CoQ(10) supplements are more antiatherogenic than CoQ(10) or VitE supplements alone and disease inhibition is associated with a decrease in aortic lipid hydroperoxides but not 7-ketocholesterol.
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Affiliation(s)
- S R Thomas
- Biochemistry Group, The Heart Research Institute, Camperdown, NSW, Australia
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30
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Abstract
Though feedforward activation (FA) is a little known principle of control in metabolic networks, there is one well-known example; namely, the activation of pyruvate kinase (PK) by fructose-1,6-biphosphate (FBP) in glycolysis. The effects of this activation on the enzyme's kinetics are well characterised, but its possible role in glycolytic control has not been determined, and, experimentally, there is as yet no direct way of modifying the enzyme to remove just the FBP activation without affecting other aspects of the enzyme's kinetics. Given this limitation, we used a detailed numerical simulation of human erythrocyte glycolysis to simulate the effects of selective removal of the activation of PK by FBP on steady-state metabolite concentrations and on the dynamic response of glycolytic flux to a sudden increase of the cell's demand for ATP. Our modelling results predict that in the absence of FA steady-state levels of metabolites within the activation loop, i.e. from FBP to phosphoenolpyruvate, would be four- to thirteen-fold higher than normal, whereas levels of ATP and metabolites outside the loop, i.e. glucose-6-phosphate, fructose-6-phosphate and pyruvate, would be lower than normal. Existing clinical evidence in a patient with haemolytic anaemia, correlated with a lack of activation of PK by FBP (Paglia D.E., Valentine W.N., Holbrook C.T., Brockway R., Blood (1983) 62 972-979), is consistent with this prediction. In response to changing demand for ATP, the model predicts that the corresponding change of glycolytic flux would entail changes of metabolite concentrations in the absence of FA, but that in its presence the levels of metabolites within the activation loop remain essentially unperturbed. Thus, our results suggest that by stabilising metabolite pools in the face of variable glycolytic flux, FA may serve to avoid perturbations of the oxygen affinity of haemoglobin (sensitive to the levels of 2,3-phosphoglycerate) and of cell osmolality that would otherwise occur during variations in the cell's demand for ATP. In addition, by significantly raising the steady-state setpoint of intermediate metabolite pools, the productivity index (ratio of glycolytic flux to total metabolites in the pathway) of glycolysis would fall almost four-fold in the absence of forward activation.
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Affiliation(s)
- M Bali
- Inserm U. 467, Necker Faculty of Medicine, University Paris-V, 156, rue de Vaugirard, 75730 Paris, France
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Abstract
Hypochlorous acid (HOCl), the major strong oxidant produced by the phagocyte enzyme myeloperoxidase, reacts readily with free amino groups to form N-chloramines. Since different N-chloramines have different stabilities and reactivities depending on their structures, we investigated the relative reactivities of three model N-chloramines and HOCl with human plasma constituents. TheN-chloramines studied were N(alpha)-acetyl-lysine chloramine (LysCA, a model of protein-associated N-chloramines), taurine chloramine (TaurCA, the primary N-chloramine produced by activated neutrophils), and monochloramine (MonoCA, a lipophilic N-chloramine). Addition of these chlorine species (100--1000 microM each) to plasma resulted in rapid loss of thiols, with the extent of thiol oxidation decreasing in the order TaurCA = LysCA > MonoCA = HOCl. The single reduced thiol of albumin was the major target. Loss of plasma ascorbate also occurred, with the extent decreasing in the order HOCl > LysCA > TaurCA > MonoCA. Experiments comparing equimolar albumin thiols and ascorbate showed that while HOCl caused equivalent loss of thiols and ascorbate, theN-chloramines reacted preferentially with thiols. The chlorine species also inactivated alpha(1)-antiproteinase, implicating oxidation of methionine residues, and ascorbate provided variable protection depending on the chlorine species involved. Together, our data indicate that in biological fluids N-chloramines react more readily with protein thiols than with methionine residues or ascorbate, and thus may cause biologically relevant, selective loss of thiol groups.
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Affiliation(s)
- A C Carr
- Linus Pauling Institute, Oregon State University, Corvallis, OR 97331-6512, USA.
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Thomas SR. MIRD Pamphlet no. 18: Administered cumulated activity for ventilation studies. J Nucl Med 2001; 42:520-6. [PMID: 11337532] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/20/2023] Open
Abstract
UNLABELLED There has been no consensus on a standard calculational approach regarding the concept of administered activity in ventilation studies involving inhaled radioisotope gas or radioaerosols. This is caused in part by a lack of knowledge regarding the actual activity that enters the lung space (as opposed to activity introduced into the delivery system) and to the extended administration times (t(a)) associated with delivery protocols. METHODS This pamphlet reviewed the three primary ventilation procedures, including rebreathing-system protocols, continuous-flow generator output techniques, and radioaerosol delivery systems. RESULTS For each technique, an analytic expression has been derived for a new parameter called lung administered cumulated activity, A(L)(0,t(a)), which is the cumulated activity in the lungs during the administration phase. In addition, another potentially useful parameter has been defined-the mean administered activity for ventilation procedures, which normalizes the administered cumulated activity in the lung over the administration period and may serve to standardize descriptions of protocols between patients and institutions. Examples are provided that illustrate these new concepts for typical ventilation protocol administration parameters. CONCLUSION The models presented can be employed to evaluate lung administered cumulated activity for use in ventilation dose estimate reports as a function of explicit variables (e.g., spirometer volume, generator output rate, wash-in half-time, administration time). In practice, it is recommended that dose estimate reports be based on measurements of cumulated activity in the lung over the administration period and normalized to this administered cumulated activity.
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Affiliation(s)
- S R Thomas
- Department of Radiology, University of Cincinnati College of Medicine, Cincinnati, Ohio 45267-0579, USA
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Donnelly LF, Emery KH, Brody AS, Laor T, Gylys-Morin VM, Anton CG, Thomas SR, Frush DP. Minimizing radiation dose for pediatric body applications of single-detector helical CT: strategies at a large Children's Hospital. AJR Am J Roentgenol 2001; 176:303-6. [PMID: 11159061 DOI: 10.2214/ajr.176.2.1760303] [Citation(s) in RCA: 386] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Adjustments of the standard helical CT protocols for adults can result in reduced radiation dose when imaging children. It is the radiologist's responsibility to critically evaluate the CT techniques used at their institution. Adjustments to CT protocols should be made to choose the appropriate mA and pitch when imaging children.
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Affiliation(s)
- L F Donnelly
- Department of Radiology, Children's Hospital Medical Center, 3333 Burnet Ave., Cincinnati, OH 45229-3039, USA
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Abstract
The AO pinless external fixator (PEF) uses trocar tipped clamps to grip the outer tibial cortex rather than pins to transfix it. Its main advantage is to avoid further contamination of the medullary canal in open tibial fractures where a nail may subsequently be used. We tested the anatomical safety of this device and its effect on plastic surgical procedures compared with a standard unilateral external fixator (UEF).The PEF and UEF were placed on two amputated limbs which were then dissected. Structures at risk were traced on ten cadaver limbs. We found that important anatomical structures were endangered by the PEF and that safe zones could not always be defined. The UEF avoided these structures. Plastic surgical approaches were made more difficult by the PEF which imposed limitations on local flap design and endangered the arterial perforators which supply them. We conclude that safety is compromised by the PEF because margins for error are small. It poses additional problems in soft tissue reconstruction and highlights the need for co-operation between plastic surgical and orthopaedic teams in choice of fixation device.
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Affiliation(s)
- S R Thomas
- Department of Orthopaedics, Royal Berkshire Hospital, London Road, Reading RG1 5AN, UK
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Abstract
OBJECTIVE To compare the ease of use of atraumatic needles with standard needles for diagnostic lumbar puncture and the incidence of headache after their use. DESIGN Double blind, randomised controlled trial. SETTING Investigation ward of a neurology unit in a university hospital. PARTICIPANTS 116 patients requiring elective diagnostic lumbar puncture. INTERVENTIONS Standardised protocol for lumbar puncture with 20 gauge atraumatic or standard needles. OUTCOME MEASURES The primary end point was intention to treat analysis of incidence of moderate to severe headache, assessed at one week by telephone interview. Secondary end points were incidence of headache at one week analysed by needle type, ease of use by operator according to a visual analogue scale, incidence of backache, and failure rate of puncture. RESULTS Valid outcome data were available for 97 of 101 patients randomised. Baseline characteristics were matched except for higher body mass index in the standard needle group. By an intention to treat analysis the absolute risk of moderate to severe headache with atraumatic needles was reduced by 26% (95% confidence interval 6% to 45%) compared with standard needles, but there was a non-significantly greater absolute risk of multiple attempts at lumbar puncture (14%, -4% to 32%). Higher body mass index was associated with an increased failure rate with atraumatic needles, but the reduced incidence of headache was maintained. The need for medical interventions was reduced by 20% (1% to 40%). CONCLUSIONS Atraumatic needles significantly reduced the incidence of moderate to severe headache and the need for medical interventions after diagnostic lumbar punctures, but they were associated with a higher failure rate than standard needles.
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Affiliation(s)
- S R Thomas
- Department of Neurology, Institute of Neurological Sciences, Southern General Hospital, Glasgow G51 4TF
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Baker JO, King MR, Adney WS, Decker SR, Vinzant TB, Lantz SE, Nieves RE, Thomas SR, Li LC, Cosgrove DJ, Himmel ME. Investigation of the cell-wall loosening protein expansin as a possible additive in the enzymatic saccharification of lignocellulosic biomass. Appl Biochem Biotechnol 2000; 84-86:217-23. [PMID: 10849790 DOI: 10.1385/abab:84-86:1-9:217] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- J O Baker
- Biotechnology Center for Fuels and Chemicals, National Renewable Energy Laboratory, Golden, CO 80401, USA.
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Thomas SR, Ray A, Hodson ME, Pitt TL. Increased sputum amino acid concentrations and auxotrophy of Pseudomonas aeruginosa in severe cystic fibrosis lung disease. Thorax 2000; 55:795-7. [PMID: 10950901 PMCID: PMC1745865 DOI: 10.1136/thorax.55.9.795] [Citation(s) in RCA: 95] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
BACKGROUND Pseudomonas aeruginosa may undergo a phenotypic change from the wild (prototrophic) type to an auxotrophic phenotype in the course of respiratory infection in patients with cystic fibrosis. The clinical significance of this is unclear. A study was undertaken to investigate whether the presence of auxotrophs of P aeruginosa in the sputum of patients with cystic fibrosis correlated with severity of respiratory disease, and whether increased sputum concentrations of amino acids were associated with the emergence of these forms. METHODS Sixty adult patients with cystic fibrosis, colonised by P aeruginosa, were recruited and baseline clinical data including lung function were recorded. Serial sputum samples were obtained before, during, and after infective exacerbations where possible. These samples were used for routine microbiological culture, assessment of auxotrophy of P aeruginosa, measurement of amino acid content, and neutrophil elastase assay. RESULTS Auxotrophy was common in patients with cystic fibrosis and 20 (33%) had a mean percentage auxotroph count of more than 50% total cfu/ml. The mean percentage auxotroph count was inversely correlated with forced expiratory volume in one second (FEV(1); tau = -0.194, p = 0.031). The median sputum amino acid concentration of the group was 12.5 mmol/l (range 0.13-40.6). The mean amino acid concentration in 33 subjects during infective exacerbations was 18.2 mmol/l (95% CI 15.1 to 21.3) compared with 12.3 mmol/l (95% CI 9.8 to 14.8) when well (p = 0.001). The amino acid content of sputum was inversely correlated with FEV(1) (tau = -0.253, p = 0.005). CONCLUSIONS P aeruginosa frequently exhibits auxotrophy in patients with cystic fibrosis, particularly in those with severe underlying pulmonary disease. The sputum amino acid content of patients with cystic fibrosis is high during infective exacerbations and correlates with pulmonary disease severity.
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Affiliation(s)
- S R Thomas
- Department of Cystic Fibrosis, Royal Brompton Hospital, London SW3 6NP, UK
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Abstract
Estimates of colonic transit times (CTT) through the three colonic segments, right colon, left colon, and rectosigmoid, are commonly based on radiopaque markers. For a given segment, CTT is usually calculated from just the number of markers visible in that segment on abdominal X-rays. This procedure is only strictly valid for the theoretical, but unrealistic, case of continuous marker ingestion (i. e., not for a single or once-daily ingestion). CTT was analyzed using the usual estimate of the mean CTT of one marker and also using a new, more realistic estimate based on the kinetic coefficients of a three-compartment colonic model. We directly compared our compartmental approach to classic CTT estimates by double-marker studies in six patients. We also retrospectively studied CTT in 148 healthy control subjects (83 males, 65 females) and 1,309 subjects with functional bowel disorders (irritable bowel syndrome or constipation). Compared with the compartmental estimates, the classic approach systematically underestimates CTT in both populations, i.e., in patients and in healthy control subjects. The relative error could easily reach 100% independent of the site of colonic transit delay. The normal values of total CTT are then 44.3+/-29.3 instead of 30.1+/-23.6 h for males and 68.2+/-54.4 instead of 47.1+/-28.2 h for females.
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Affiliation(s)
- M Bouchoucha
- Hôpital Laennec, Laboratory of Digestive Physiology, 75007 Paris, France.
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Abstract
Since anaerobic glycolysis yields two lactates for each glucose consumed and since it is reported to be a major source of ATP for inner medullary (IM) cell maintenance, it is a likely source of "external" IM osmoles. It has long been known that such an osmole source could theoretically contribute to the "single-effect" of the urine concentrating mechanism, but there was previously no suggestion of a plausible source. I used numerical simulation to estimate axial gradients of lactate and glucose that might be accumulated by countercurrent recycling in IM vasa recta (IMVR). Based on measurements in other tissues, anaerobic glycolysis (assumed to be independent of diuretic state) was estimated to consume approximately 20% of the glucose delivered to the IM. IM tissue mass and axial distribution of loops and vasa recta were according to reported values for rat and other rodents. Lactate (P(LAC)) and glucose (P(GLU)) permeabilities were varied over a range of plausible values. The model results suggest that P(LAC) of 100 x 10(-5) cm/s (similar to measured permeabilities for other small solutes) is sufficiently high to ensure efficient lactate recycling. By contrast, it was necessary in the model to reduce P(GLU) to a small fraction of this value (1/25th) to avoid papillary glucose depletion by countercurrent shunting. The results predict that IM lactate production could suffice to build a significant steady-state axial lactate gradient in the IM interstitium. Other modeling studies (Jen JF and Stephenson JL. Bull Math Biol 56: 491-514, 1994; and Thomas SR and Wexler AS. Am J Physiol Renal Fluid Electrolyte Physiol 269: F159-F171, 1995) have shown that 20-100 mosmol/kgH(2)O of unspecified external, interstitial, osmolytes could greatly improve IM concentrating ability. The present study gives several plausible scenarios consistent with accumulation of metabolically produced lactate osmoles, although only to the lower end of this range. For example, if 20% of entering glucose is consumed, the model predicts that papillary lactate would attain about 15 mM assuming vasa recta outflow is increased 30% by fluid absorbed from the nephrons and collecting ducts and that this lactate gradient would double if IM blood flow were reduced by one-half, as may occur in antidiuresis. Several experimental tests of the hypothesis are indicated.
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Affiliation(s)
- S R Thomas
- Institut National de la Santé et de la Recherche Médicale Unité 467, Necker Faculty of Medicine, F-75015 Paris, France.
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Abstract
The oxidation theory of atherosclerosis proposes that the oxidative modification of low-density lipoproteins (LDL) plays a central role in the disease. Although a direct causative role of LDL oxidation for atherogenesis has not been established, oxidized lipoproteins are detected in atherosclerotic lesions, and in vitro oxidized LDL exhibits putative pro-atherogenic activities. alpha-Tocopherol (alpha-TOH; vitamin E), the major lipid-soluble antioxidant present in lipoproteins, is thought to be antiatherogenic. However, results of vitamin E interventions on atherosclerosis in experimental animals and cardiovascular disease in humans have been inconclusive. Also, recent mechanistic studies demonstrate that the role of alpha-TOH during the early stages of lipoprotein lipid peroxidation is complex and that the vitamin does not act as a chain-breaking antioxidant. In the absence of co-antioxidants, compounds capable of reducing the alpha-TOH radical and exporting the radical from the lipoprotein particle, alpha-TOH exhibits anti- or pro-oxidant activity for lipoprotein lipids depending on the degree of radical flux and reactivity of the oxidant. The model of tocopherol-mediated peroxidation (TMP) explains the complex molecular action of alpha-TOH during lipoprotein lipid peroxidation and antioxidation. This article outlines the salient features of TMP, comments on whether TMP is relevant for in vivo lipoprotein lipid oxidation, and discusses how co-antioxidants may be required to attenuate lipoprotein lipid oxidation in vivo and perhaps atherosclerosis.
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Affiliation(s)
- S R Thomas
- The Biochemistry Group, The Heart Research Institute, Sydney, Australia
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Abstract
The heme enzyme indoleamine 2,3-dioxygenase (IDO) oxidizes the pyrrole moiety of L-tryptophan (Trp) and other indoleamines and represents the initial and rate-limiting enzyme of the kynurenine (Kyn) pathway. IDO is a unique enzyme in that it can utilize superoxide anion radical (O2*- ) as both a substrate and a co-factor. The latter role is due to the ability of O2*- to reduce inactive ferric-IDO to the active ferrous form. Nitrogen monoxide (*NO) and H2O2 inhibit the dioxygenase and various inter-relationships between the nitric oxide synthase- and IDO-initiated amino acid degradative pathways exist. Induction of IDO and metabolism of Trp along the Kyn pathway is implicated in a variety of physiological and pathophysiological processes, including anti-microbial and anti-tumor defense, neuropathology, immunoregulation and antioxidant activity. Antioxidant activity may arise from O2*- scavenging by IDO and formation of the potent radical scavengers and Kyn pathway metabolites, 3-hydroxyanthranilic acid and 3-hydroxykynurenine. Under certain conditions, these aminophenols and other Kyn pathway metabolites may exhibit pro-oxidant activities. This article reviews findings indicating that redox reactions are involved in the regulation of IDO and Trp metabolism along the Kyn pathway and also participate in the biological activities exhibited by Kyn pathway metabolites.
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Affiliation(s)
- S R Thomas
- The Biochemistry Group, The Heart Research Institute, Sydney, New South Wales, Australia.
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Thomas SR, Stocker R. Antioxidant activities and redox regulation of interferon-gamma-induced tryptophan metabolism in human monocytes and macrophages. Adv Exp Med Biol 2000; 467:541-52. [PMID: 10721098 DOI: 10.1007/978-1-4615-4709-9_67] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
This article summarises studies supporting the proposal that induction of L-tryptophan (Trp) degradation along the kynurenine pathway in human monocytes and macrophages by interferon-gamma (IFN gamma) represents a novel extracellular antioxidant defence that acts to prevent inadvertent oxidative damage to host tissue during inflammation. The studies show that formation and release of the aminophenolic antioxidant 3-hydroxyanthranilic acid (3-HAA) is responsible for the ability of IFN gamma-primed human macrophages to inhibit the oxidation of low density lipoprotein (LDL); an event implicated as an important event in atherogenesis. 3-HAA efficiently inhibits LDL oxidation by acting as an aqueous oxidant scavenger and a synergist for LDL-associated vitamin E. Indoleamine 2,3-dioxygenase activity (IDO) is the initial and rate limiting enzyme of Trp degradation along the kynurenine pathway. Nitric oxide inhibits IDO activity in IFN gamma-primed human macrophages and this may represent a physiological regulatory mechanism of the dioxygenase during inflammation.
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Affiliation(s)
- S R Thomas
- Biochemistry Group, Heart Research Institute, Sydney, Australia
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Thomas SR, Kharitonov SA, Scott SF, Hodson ME, Barnes PJ. Nasal and exhaled nitric oxide is reduced in adult patients with cystic fibrosis and does not correlate with cystic fibrosis genotype. Chest 2000; 117:1085-9. [PMID: 10767244 DOI: 10.1378/chest.117.4.1085] [Citation(s) in RCA: 84] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
STUDY OBJECTIVES Inducible nitric oxide synthase (iNOS) is upregulated in a number of inflammatory lung conditions, and exhaled nitric oxide (NO) concentration is increased. However, previous studies in children with cystic fibrosis (CF) have shown that exhaled NO is reduced. The purpose of this investigation was to study exhaled NO concentration in adults with CF, and to investigate the effect of CF genotype and respiratory tract infection on this measurement. DESIGN Exhaled and nasal NO levels were measured in 54 adult CF subjects and 37 healthy nonsmoking age-matched subjects using a chemiluminesence analyzer. Spirometry (FEV(1) and FVC), CF genotype, and bacterial colonization were also recorded. SETTING This study was conducted at a national CF center. RESULTS The mean age of patients was 26.9 years, and the mean FEV(1) was 50.5% predicted (range, 17 to 104%). Nasal NO in the CF patients (mean, 520 parts per billion [ppb]; confidence interval [CI], 452 to 588) was significantly lower (p < 0.001) than in control subjects (987 ppb; CI, 959 to 1,015). Exhaled NO was significantly lower (p < 0. 001) in CF patients (5.0 ppb; CI, 4.1 to 6.1) than in control subjects (7.3 ppb; CI, 6.8 to 7.8). FEV(1) did not correlate with nasal or exhaled NO. No association was observed between genotype and NO values or colonization with Pseudomonas aeruginosa. CONCLUSIONS Despite the airway inflammation that is characteristic of CF, both nasal and exhaled NO were reduced. There was no association with genotype or infection status. As NO has bacteriostatic effects and may augment mucociliary clearance, this observation may be of clinical importance.
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Affiliation(s)
- S R Thomas
- Department of Cystic Fibrosis, Royal Brompton and Hariefiled NHS Trust, London, UK
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Bina JE, Alm RA, Uria-Nickelsen M, Thomas SR, Trust TJ, Hancock RE. Helicobacter pylori uptake and efflux: basis for intrinsic susceptibility to antibiotics in vitro. Antimicrob Agents Chemother 2000; 44:248-54. [PMID: 10639345 PMCID: PMC89666 DOI: 10.1128/aac.44.2.248-254.2000] [Citation(s) in RCA: 100] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/1999] [Accepted: 11/06/1999] [Indexed: 01/26/2023] Open
Abstract
We previously demonstrated (M. M. Exner, P. Doig, T. J. Trust, and R. E. W. Hancock, Infect. Immun. 63:1567-1572, 1995) that Helicobacter pylori has at least one nonspecific porin, HopE, which has a low abundance in the outer membrane but forms large channels. H. pylori is relatively susceptible to most antimicrobial agents but less susceptible to the polycationic antibiotic polymyxin B. We demonstrate here that H. pylori is able to take up higher basal levels of the hydrophobic fluorescent probe 1-N-phenylnaphthylamine (NPN) than Pseudomonas aeruginosa or Escherichia coli, consistent with its enhanced susceptibility to hydrophobic agents. Addition of polymyxin B led to a further increase in NPN uptake, indicative of a self-promoted uptake pathway, but it required a much higher amount of polymyxin B to yield a 50% increase in NPN uptake in H. pylori (6 to 8 microg/ml) than in P. aeruginosa or E. coli (0.3 to 0.5 microg/ml), suggesting that H. pylori has a less efficient self-promoted uptake pathway. Since intrinsic resistance involves the collaboration of restricted outer membrane permeability and secondary defense mechanisms, such as periplasmic beta-lactamase (which H. pylori lacks) or efflux, we examined the possible role of efflux in antibiotic susceptibility. We had previously identified in H. pylori 11637 the presence of portions of three genes with homology to potential restriction-nodulation-division (RND) efflux systems. It was confirmed that H. pylori contained only these three putative RND efflux systems, named here hefABC, hefDEF, and hefGHI, and that the hefGHI system was expressed only in vivo while the two other RND systems were expressed both in vivo and in vitro. In uptake studies, there was no observable energy-dependent tetracycline, chloramphenicol, or NPN efflux activity in H. pylori. Independent mutagenesis of the three putative RND efflux operons in the chromosome of H. pylori had no effect on the in vitro susceptibility of H. pylori to 19 antibiotics. These results, in contrast to what is observed in E. coli, P. aeruginosa, and other clinically important gram-negative bacteria, suggest that active efflux does not play a role in the intrinsic resistance of H. pylori to antibiotics.
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Affiliation(s)
- J E Bina
- Department of Microbiology and Immunology, The University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z3
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Dai Z, Hooker BS, Anderson DB, Thomas SR. Expression of Acidothermus cellulolyticus endoglucanase E1 in transgenic tobacco: biochemical characteristics and physiological effects. Transgenic Res 2000; 9:43-54. [PMID: 10853268 DOI: 10.1023/a:1008922404834] [Citation(s) in RCA: 81] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The expression of the Acidothermus cellulolyticus endoglucanase E1 gene in transgenic tobacco (Nicotiana tabacum) was examined in this study, where E1 coding sequence was transcribed under the control of a leaf specific Rubisco small subunit promoter (tomato RbcS-3C). Targeting the E1 protein to the chloroplast was established using a chloroplast transit peptide of Rubisco small subunit protein (tomato RbcS-2A) and confirmed by immunocytochemistry. The E1 produced in transgenic tobacco plants was found to be biologically active, and to accumulate in leaves at levels of up to 1.35% of total soluble protein. Optimum temperature and pH for E1 enzyme activity in leaf extracts were 81 degrees C and 5.25, respectively. E1 activity remained constant on a gram fresh leaf weight basis, but dramatically increased on a total leaf soluble protein basis as leaves aged, or when leaf discs were dehydrated. E1 protein in old leaves, or after 5 h dehydration, was partially degraded although E1 activity remained constant. Transgenic plants exhibited normal growth and developmental characteristics with photosynthetic rates similar to those of untransformed SR1 tobacco plants. Results from these biochemical and physiological analyses suggest that the chloroplast is a suitable cellular compartment for accumulation of the hydrolytic E1 enzyme.
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Affiliation(s)
- Z Dai
- Pacific Northwest National Laboratory, Richland, WA 99352, USA.
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McHenry CR, Thomas SR, Slusarczyk SJ, Khiyami A. Follicular or Hürthle cell neoplasm of the thyroid: can clinical factors be used to predict carcinoma and determine extent of thyroidectomy? Surgery 1999; 126:798-802; discussion 802-4. [PMID: 10520931] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/14/2023]
Abstract
BACKGROUND Fine-needle aspiration biopsy (FNAB) and frozen section exam are of limited or no value in distinguishing benign and malignant follicular or Hürthle cell neoplasms of the thyroid gland. METHODS Patients who underwent thyroidectomy for treatment of a follicular or Hürthle cell neoplasm between 1990 and 1998 were identified and evaluated for age, gender, head and neck irradiation, nodule size, and cytologic atypia to determine whether clinical factors were predictive of carcinoma. RESULTS Of the 352 patients evaluated for nodular thyroid disease, 75 (21%) underwent thyroidectomy after an indeterminate FNAB finding, 66 with follicular and 9 with a Hürthle cell neoplasm. Seventeen (23%) of the patients had carcinoma-follicular variant of papillary (10), follicular (6), and Hürthle cell (1). Carcinoma was diagnosed in 15 of 64 women and 2 of 11 men (P > .05). The mean age was 43 +/- 21 years and 50 +/- 16 years, respectively, in patients with and without carcinoma (P > . 05). Three patients had previous neck irradiation and none had carcinoma. Mean nodule size was 4.2 +/- 2.7 cm and 4.3 +/- 3.5 cm, respectively, in patients with and without carcinoma (P > . 05). Cytologic atypia was present in 8 of 17 patients with carcinoma and 20 of 58 patients without carcinoma (P > .05). CONCLUSIONS Clinical factors were not helpful in predicting carcinoma in patients with an indeterminate FNAB finding and thus cannot be used to reliably select patients for more extensive thyroidectomy.
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Affiliation(s)
- C R McHenry
- Department of Surgery, MetroHealth Medical Center, Case Western Reserve University School of Medicine, Cleveland, Ohio 44109-1998, USA
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McGoron AJ, Kassing WM, Thomas SR, Samaratunga RC, Pratt RG, Elson HR, Pipes DW. Intravascular irradiation using Re-186 liquid-filled balloon catheters: correlation between experimental and theoretical studies. Cardiovasc Radiat Med 1999; 1:368-75. [PMID: 10828567 DOI: 10.1016/s1522-1865(00)00032-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE Optimization of intravascular radiation to reduce stenosis following coronary angioplasty requires the ability to predict the patterns of radiation dose distribution. This investigation evaluated the agreement between Monte Carlo simulations and experimental radiation dose measurements for a radioisotope liquid-filled balloon catheter in a tissue equivalent phantom. METHODS AND MATERIALS Direct measurements of the radiation dose from Re-186 liquid-filled balloons were made using thermoluminescent dosimeters (TLDs) and radiochromic film. Monte Carlo simulations were carried out using the Monte Carlo N-Particle code system (MCNP4B). RESULTS The Monte Carlo generated dose values agreed with the experimentally determined results within the statistical uncertainty. A slightly higher penetration was indicated by regression analysis for the TLD data relative to the MCNP4B prediction that may be due to experimental configuration anomalies. For this balloon catheter, approximately 55 mCi of Re-186 will deliver 15 Gy at a 0.5 mm depth in tissue equivalent material in 5 min. CONCLUSIONS Correlation between experimentally measured dose values and Monte Carlo computation supports the position that MCNP4B simulations constitute a valuable tool for investigating various clinical therapy designs. The agreement between Monte Carlo calculations and experiments provide confidence in applying MCNP4B to more sophisticated geometries of interest, and other methods of intravascular radiation dose delivery.
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Affiliation(s)
- A J McGoron
- Department of Radiology, University of Cincinnati, Ohio, USA.
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Godbole S, Decker SR, Nieves RA, Adney WS, Vinzant TB, Baker JO, Thomas SR, Himmel ME. Cloning and expression of Trichoderma reesei cellobiohydrolase I in Pichia pastoris. Biotechnol Prog 1999; 15:828-33. [PMID: 10514252 DOI: 10.1021/bp9901116] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Pichia pastoris was transformed with the Trichoderma reesei cbh1 gene, and the recombinant enzyme was purified and analyzed kinetically and by circular dichroism. The P. pastoris rCBH I was recognized by MoAb raised to T. reesei CBH I but was found in multiple molecular weight species on SDS-PAGE gels. Carbohydrate content determination and SDS-PAGE western analysis indicated that the recombinant protein was hyperglycosylated, although a species very similar in molecular weight to the T. reesei enzyme could be isolated chromatographically. The P. pastoris rCBH I also demonstrated activity toward soluble and insoluble substrates (i.e., pNPL and Sigmacell), although at a level significantly lower than the wild-type enzyme. More seriously, the yeast-expressed enzyme showed non-wild-type secondary structure by circular dichroism. We conclude that P. pastoris may not serve as an adequate host for the site-directed mutagenesis of T. reesei CBH I.
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Affiliation(s)
- S Godbole
- Biotechnology Center for Fuels and Chemicals, National Renewable Energy Laboratory, Golden, Colorado 80401, USA
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Thomas SR, Stabin MG, Chen CT, Samaratunga RC. MIRD Pamphlet No. 14 revised: A dynamic urinary bladder model for radiation dose calculations. Task Group of the MIRD Committee, Society of Nuclear Medicine. J Nucl Med 1999; 40:102S-123S. [PMID: 10210232] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/12/2023] Open
Abstract
UNLABELLED The constant-volume urinary bladder model in the standard MIRD Pamphlet No. 5 (Revised) phantom has recognized limitations. Various investigators have developed detailed models incorporating more physiologically realistic features, such as expanding bladder contents and residual volume, and variable urinary input rate, initial volume and first void time. We have reviewed these published models and have developed a new model for calculation of radiation absorbed dose to the urinary bladder wall incorporating these aspects. METHODS The model consists of a spherical source with variable volume to simulate the bladder contents and a wall represented by a spherical shell of constant volume. The wall thickness varies as the source expands or contracts. The model provides for variable urine entry rate (three different hydration states), initial bladder contents volume, residual volume and first void time. The voiding schedule includes an extended nighttime gap during which the urine entry rate is reduced to one-half the daytime rate. RESULTS Radiation-absorbed dose estimates have been calculated for the bladder wall surface (including photon and electron components) and at several depths in the wall (electron component) for 2-18F-fluoro-2-deoxy-D-glucose, 99mTc-diethylenetriaminepentaacetic acid (DTPA), 99mTc-HEDP, 99mTc-pertechnetate, 99mTc-red blood cells (RBCs), 99mTc-glucoheptonate, 99mTc-mercaptoacetyltriglicine chelator (MAG3), 99mTc-methylene diphosphonate (MDP), 99mTc-hexamethylpropylene amine oxime (HMPAO), 99mTc-human serum albumin (HSA), 99mTc-MIBI (rest and stress), 123I-/124I-/131I-OIH, 123I/131I-NaI, 125I-iothalamate, 111In-DTPA and 89Sr-SrCl. CONCLUSION The new model tends to give a higher radiation absorbed dose to the bladder wall surface than the previous models. Large initial bladder volumes and higher rates of urine flow into the bladder result in lower bladder wall dose. The optimal first voiding time is from 40 min to 3 hr postadministration, depending on radiopharmaceutical. The data as presented in tabular and graphic form for each compound provide guidance for establishing radiation absorbed dose reduction protocols.
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Affiliation(s)
- S R Thomas
- Department of Radiology, University of Cincinnati College of Medicine, Ohio 45267-0579, USA
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