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Métayer LE, Brown RD, Carlebur S, Burke GAA, Brown GC. Mechanisms of cell death induced by arginase and asparaginase in precursor B-cell lymphoblasts. Apoptosis 2020; 24:145-156. [PMID: 30578463 PMCID: PMC6373273 DOI: 10.1007/s10495-018-1506-3] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Arginase has therapeutic potential as a cytotoxic agent in some cancers, but this is unclear for precursor B acute lymphoblastic leukaemia (pre-B ALL), the commonest form of childhood leukaemia. We compared arginase cytotoxicity with asparaginase, currently used in pre-B ALL treatment, and characterised the forms of cell death induced in a pre-B ALL cell line 697. Arginase and asparaginase both efficiently killed 697 cells and mature B lymphoma cell line Ramos, but neither enzyme killed normal lymphocytes. Arginase depleted cellular arginine, and arginase-treated media induced cell death, blocked by addition of arginine or arginine-precursor citrulline. Asparaginase depleted both asparagine and glutamine, and asparaginase-treated media induced cell death, blocked by asparagine, but not glutamine. Both enzymes induced caspase cleavage and activation, chromatin condensation and phosphatidylserine exposure, indicating apoptosis. Both arginase- and asparaginase-induced death were blocked by caspase inhibitors, but with different sensitivities. BCL-2 overexpression inhibited arginase- and asparaginase-induced cell death, but did not prevent arginase-induced cytostasis, indicating a different mechanism of growth arrest. An autophagy inhibitor, chloroquine, had no effect on the cell death induced by arginase, but doubled the cell death induced by asparaginase. In conclusion, arginase causes death of lymphoblasts by arginine-depletion induced apoptosis, via mechanism distinct from asparaginase. Therapeutic implications for childhood ALL include: arginase might be used as treatment (but antagonised by dietary arginine and citrulline), chloroquine may enhance efficacy of asparaginase treatment, and partial resistance to arginase and asparaginase may develop by BCL-2 expression. Arginase or asparaginase might potentially be used to treat Burkitt lymphoma.
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Affiliation(s)
- Lucy E Métayer
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QW, UK
| | - Richard D Brown
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QW, UK
| | - Saskia Carlebur
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QW, UK
| | - G A Amos Burke
- Department of Paediatrics, University of Cambridge, Cambridge, CB2 OQQ, UK
| | - Guy C Brown
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QW, UK.
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Ebselen alters cellular oxidative status and induces endoplasmic reticulum stress in rat hippocampal astrocytes. Toxicology 2016; 357-358:74-84. [DOI: 10.1016/j.tox.2016.06.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2016] [Revised: 06/01/2016] [Accepted: 06/05/2016] [Indexed: 01/08/2023]
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Kesel AJ, Day CW, Montero CM, Schinazi RF. A new oxygen modification cyclooctaoxygen binds to nucleic acids as sodium crown complex. Biochim Biophys Acta Gen Subj 2016; 1860:785-94. [PMID: 26825775 PMCID: PMC4780752 DOI: 10.1016/j.bbagen.2016.01.022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2015] [Accepted: 01/19/2016] [Indexed: 11/28/2022]
Abstract
BACKGROUND Oxygen exists in two gaseous and six solid allotropic modifications. An additional allotropic modification of oxygen, the cyclooctaoxygen, was predicted to exist in 1990. METHODS Cyclooctaoxygen sodium was synthesized in vitro from atmospheric oxygen, or catalase effect-generated oxygen, under catalysis of cytosine nucleosides and either ninhydrin or eukaryotic low-molecular weight RNA. Thin-layer chromatographic mobility shift assays were applied on specific nucleic acids and the cyclooctaoxygen sodium complex. RESULTS We report the first synthesis and characterization of cyclooctaoxygen as its sodium crown complex, isolated in the form of three cytosine nucleoside hydrochloride complexes. The cationic cyclooctaoxygen sodium complex is shown to bind to nucleic acids (RNA and DNA), to associate with single-stranded DNA and spermine phosphate, and to be essentially non-toxic to cultured mammalian cells at 0.1-1.0mM concentration. CONCLUSIONS We postulate that cyclooctaoxygen is formed in most eukaryotic cells in vivo from dihydrogen peroxide in a catalase reaction catalyzed by cytidine and RNA. A molecular biological model is deduced for a first epigenetic shell of eukaryotic in vivo DNA. This model incorporates an epigenetic explanation for the interactions of the essential micronutrient selenium (as selenite) with eukaryotic in vivo DNA. GENERAL SIGNIFICANCE Since the sperminium phosphate/cyclooctaoxygen sodium complex is calculated to cover the active regions (2.6%) of bovine lymphocyte interphase genome, and 12.4% of murine enterocyte mitotic chromatin, we propose that the sperminium phosphate/cyclooctaoxygen sodium complex coverage of nucleic acids is essential to eukaryotic gene regulation and promoted proto-eukaryotic evolution.
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Affiliation(s)
- Andreas J Kesel
- Chammünsterstr. 47, D-81827 München, Bayern/Bavaria, Germany.
| | - Craig W Day
- Institute for Antiviral Research, Department of Animal, Dairy and Veterinary Science, Utah State University, Logan, UT 84322, USA
| | - Catherine M Montero
- Center for AIDS Research, Laboratory of Biochemical Pharmacology, Department of Pediatrics, Emory University School of Medicine, Atlanta, GA 30322, USA; Veterans Affairs Medical Center, Decatur, GA 30033, USA
| | - Raymond F Schinazi
- Center for AIDS Research, Laboratory of Biochemical Pharmacology, Department of Pediatrics, Emory University School of Medicine, Atlanta, GA 30322, USA; Veterans Affairs Medical Center, Decatur, GA 30033, USA
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Small molecules reveal an alternative mechanism of Bax activation. Biochem J 2016; 473:1073-83. [PMID: 26916338 PMCID: PMC4847155 DOI: 10.1042/bcj20160118] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2016] [Accepted: 02/23/2016] [Indexed: 12/20/2022]
Abstract
The pro-apoptotic protein Bax commits a cell to death by permeabilizing the mitochondrial outer membrane (MOM). To obtain small-molecule probes for elucidating the molecular mechanism(s) of Bax activation, we screened for compounds that induced Bax-mediated liposome permeabilization. We identified five structurally different small molecules that promoted both Bax targeting to and oligomerization at membranes. All five compounds initiated Bax oligomerization in the absence of membranes by a mechanism unlike Bax activation by Bcl-2 homology 3 domain (BH3) proteins. Some of the compounds induced Bax/Bak-dependent apoptosis in cells. Activation of Bax by the most active compound was poorly inhibited by the anti-apoptotic protein Bcl-XL and requires a cysteine residue at position 126 of Bax that is not required for activation by BH3 proteins. Our results reveal a novel pathway for Bax activation independent of pro-apoptotic BH3 proteins that may have important implications for the regulation of Bax activity in cells.
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Mussai F, Egan S, Higginbotham-Jones J, Perry T, Beggs A, Odintsova E, Loke J, Pratt G, U KP, Lo A, Ng M, Kearns P, Cheng P, De Santo C. Arginine dependence of acute myeloid leukemia blast proliferation: a novel therapeutic target. Blood 2015; 125:2386-96. [PMID: 25710880 PMCID: PMC4416943 DOI: 10.1182/blood-2014-09-600643] [Citation(s) in RCA: 116] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2014] [Accepted: 02/11/2015] [Indexed: 12/14/2022] Open
Abstract
Acute myeloid leukemia (AML) is one of the most common acute leukemias in adults and children, yet significant numbers of patients relapse and die of disease. In this study, we identify the dependence of AML blasts on arginine for proliferation. We show that AML blasts constitutively express the arginine transporters CAT-1 and CAT-2B, and that the majority of newly diagnosed patients' blasts have deficiencies in the arginine-recycling pathway enzymes argininosuccinate synthase and ornithine transcarbamylase, making them arginine auxotrophic. BCT-100, a pegylated human recombinant arginase, leads to a rapid depletion in extracellular and intracellular arginine concentrations, resulting in arrest of AML blast proliferation and a reduction in AML engraftment in vivo. BCT-100 as a single agent causes significant death of AML blasts from adults and children, and acts synergistically in combination with cytarabine. Using RNA sequencing, 20 further candidate genes which correlated with resistance have been identified. Thus, AML blasts are dependent on arginine for survival and proliferation, as well as depletion of arginine with BCT-100 of clinical value in the treatment of AML.
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MESH Headings
- Adolescent
- Aged
- Animals
- Antimetabolites, Antineoplastic/therapeutic use
- Arginase/therapeutic use
- Arginine/metabolism
- Child
- Child, Preschool
- Cytarabine/therapeutic use
- Enzyme Therapy
- Female
- Humans
- Infant
- Leukemia, Myeloid, Acute/drug therapy
- Leukemia, Myeloid, Acute/enzymology
- Leukemia, Myeloid, Acute/metabolism
- Leukemia, Myeloid, Acute/pathology
- Male
- Mice, SCID
- Middle Aged
- Recombinant Proteins/therapeutic use
- Tumor Cells, Cultured
- Young Adult
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Affiliation(s)
- Francis Mussai
- School of Cancer Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Sharon Egan
- School of Veterinary Medicine and Science, University of Nottingham, Nottingham, United Kingdom
| | | | - Tracey Perry
- School of Cancer Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Andrew Beggs
- School of Cancer Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Elena Odintsova
- School of Cancer Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Justin Loke
- School of Cancer Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Guy Pratt
- School of Cancer Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Kin Pong U
- Bio-cancer Treatment International Ltd, Hong Kong Science Park, Shatin, New Territories, Hong Kong; and
| | - Anthony Lo
- Department of Anatomic Pathology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong
| | - Margaret Ng
- Department of Anatomic Pathology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong
| | - Pamela Kearns
- School of Cancer Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Paul Cheng
- Bio-cancer Treatment International Ltd, Hong Kong Science Park, Shatin, New Territories, Hong Kong; and
| | - Carmela De Santo
- School of Cancer Sciences, University of Birmingham, Birmingham, United Kingdom
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The seleno-organic compound ebselen impairs mitochondrial physiology and induces cell death in AR42J cells. Toxicol Lett 2014; 229:465-73. [DOI: 10.1016/j.toxlet.2014.07.025] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2014] [Revised: 07/22/2014] [Accepted: 07/23/2014] [Indexed: 11/20/2022]
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Santofimia-Castaño P, Salido GM, González A. Ebselen alters mitochondrial physiology and reduces viability of rat hippocampal astrocytes. DNA Cell Biol 2013; 32:147-55. [PMID: 23496767 DOI: 10.1089/dna.2012.1939] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
The seleno-organic compound and radical scavenger ebselen (2-phenyl-1,2-benzisoselenazol-3(2H)-one) have been extensively employed as an anti-inflammatory and neuroprotective compound. However, its glutathione peroxidase activity at the expense of cellular thiols groups could underlie certain deleterious actions of the compound on cell physiology. In this study, we have analyzed the effect of ebselen on rat hippocampal astrocytes in culture. Cellular viability, the intracellular free-Ca(2+) concentration ([Ca(2+)]c), the mitochondrial free-Ca(2+) concentration ([Ca(2+)]m), and mitochondrial membrane potential (ψm) were analyzed. The caspase-3 activity was also assayed. Our results show that cell viability was reduced by treatment of cells with ebselen, depending on the concentration employed. In the presence of ebselen, we observed an initial transient increase in [Ca(2+)]c that was then followed by a progressive increase to an elevated plateau. We also observed a transient increase in [Ca(2+)]m in the presence of ebselen that returned toward a value over the prestimulation level. The compound induced depolarization of ψm and altered the permeability of the mitochondrial membrane. Additionally, a disruption of the mitochondrial network was observed. Finally, we did not detect changes in caspase-3 activation in response to ebselen treatment. Collectively, these data support the likelihood of ebselen, depending on the concentration employed, reduces viability of rat hippocampal astrocytes via its action on the mitochondrial activity. These may be early effects that do not involve caspase-3 activation. We conclude that, depending on the concentration used, ebselen might exert deleterious actions on astrocyte physiology that could compromise cell function.
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