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Hambarde S, Manalo JM, Baskin DS, Sharpe MA, Helekar SA. Spinning magnetic field patterns that cause oncolysis by oxidative stress in glioma cells. Sci Rep 2023; 13:19264. [PMID: 37935811 PMCID: PMC10630398 DOI: 10.1038/s41598-023-46758-w] [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] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Accepted: 11/04/2023] [Indexed: 11/09/2023] Open
Abstract
Raising reactive oxygen species (ROS) levels in cancer cells to cause macromolecular damage and cell death is a promising anticancer treatment strategy. Observations that electromagnetic fields (EMF) elevate intracellular ROS and cause cancer cell death, have led us to develop a new portable wearable EMF device that generates spinning oscillating magnetic fields (sOMF) to selectively kill cancer cells while sparing normal cells in vitro and to shrink GBM tumors in vivo through a novel mechanism. Here, we characterized the precise configurations and timings of sOMF stimulation that produce cytotoxicity due to a critical rise in superoxide in two types of human glioma cells. We also found that the antioxidant Trolox reverses the cytotoxic effect of sOMF on glioma cells indicating that ROS play a causal role in producing the effect. Our findings clarify the link between the physics of magnetic stimulation and its mechanism of anticancer action, facilitating the development of a potential new safe noninvasive device-based treatment for GBM and other gliomas.
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Affiliation(s)
- Shashank Hambarde
- Kenneth R. Peak Center for Brain and Pituitary Tumor Treatment and Research, Houston Methodist Hospital, Houston, TX, USA
- Department of Neurosurgery, Houston Methodist Hospital, Houston, TX, USA
- Houston Methodist Research Institute, Houston, TX, USA
| | - Jeanne M Manalo
- Kenneth R. Peak Center for Brain and Pituitary Tumor Treatment and Research, Houston Methodist Hospital, Houston, TX, USA
- Department of Neurosurgery, Houston Methodist Hospital, Houston, TX, USA
- Houston Methodist Research Institute, Houston, TX, USA
| | - David S Baskin
- Kenneth R. Peak Center for Brain and Pituitary Tumor Treatment and Research, Houston Methodist Hospital, Houston, TX, USA
- Department of Neurosurgery, Houston Methodist Hospital, Houston, TX, USA
- Houston Methodist Research Institute, Houston, TX, USA
- Department of Neurosurgery, Weill Cornell Medical College, New York, NY, USA
| | - Martyn A Sharpe
- Kenneth R. Peak Center for Brain and Pituitary Tumor Treatment and Research, Houston Methodist Hospital, Houston, TX, USA
- Department of Neurosurgery, Houston Methodist Hospital, Houston, TX, USA
- Houston Methodist Research Institute, Houston, TX, USA
| | - Santosh A Helekar
- Kenneth R. Peak Center for Brain and Pituitary Tumor Treatment and Research, Houston Methodist Hospital, Houston, TX, USA.
- Department of Neurosurgery, Houston Methodist Hospital, Houston, TX, USA.
- Houston Methodist Research Institute, Houston, TX, USA.
- Department of Neurosurgery, Weill Cornell Medical College, New York, NY, USA.
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2
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Sharpe MA, Baskin DS, Pichumani K, Ijare OB, Helekar SA. Rotating Magnetic Fields Inhibit Mitochondrial Respiration, Promote Oxidative Stress and Produce Loss of Mitochondrial Integrity in Cancer Cells. Front Oncol 2021; 11:768758. [PMID: 34858847 PMCID: PMC8631329 DOI: 10.3389/fonc.2021.768758] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [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: 09/02/2021] [Accepted: 10/20/2021] [Indexed: 11/13/2022] Open
Abstract
Electromagnetic fields (EMF) raise intracellular levels of reactive oxygen species (ROS) that can be toxic to cancer cells. Because weak magnetic fields influence spin state pairing in redox-active radical electron pairs, we hypothesize that they disrupt electron flow in the mitochondrial electron transport chain (ETC). We tested this hypothesis by studying the effects of oscillating magnetic fields (sOMF) produced by a new noninvasive device involving permanent magnets spinning with specific frequency and timing patterns. We studied the effects of sOMF on ETC by measuring the consumption of oxygen (O2) by isolated rat liver mitochondria, normal human astrocytes, and several patient derived brain tumor cells, and O2 generation/consumption by plant cells with an O2 electrode. We also investigated glucose metabolism in tumor cells using 1H and 13C nuclear magnetic resonance and assessed mitochondrial alterations leading to cell death by using fluorescence microscopy with MitoTracker™ and a fluorescent probe for Caspase 3 activation. We show that sOMF of appropriate field strength, frequency, and on/off profiles completely arrest electron transport in isolated, respiring, rat liver mitochondria and patient derived glioblastoma (GBM), meningioma and diffuse intrinsic pontine glioma (DIPG) cells and can induce loss of mitochondrial integrity. These changes correlate with a decrease in mitochondrial carbon flux in cancer cells and with cancer cell death even in the non-dividing phase of the cell cycle. Our findings suggest that rotating magnetic fields could be therapeutically efficacious in brain cancers such as GBM and DIPG through selective disruption of the electron flow in immobile ETC complexes.
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Affiliation(s)
- Martyn A Sharpe
- Kenneth R. Peak Center for Brain and Pituitary Tumor Treatment and Research, Houston Methodist Hospital, Houston, TX, United States.,Department of Neurosurgery, Houston Methodist Hospital, Houston, TX, United States.,Department of Neurosurgery, Houston Methodist Research Institute, Houston, TX, United States
| | - David S Baskin
- Kenneth R. Peak Center for Brain and Pituitary Tumor Treatment and Research, Houston Methodist Hospital, Houston, TX, United States.,Department of Neurosurgery, Houston Methodist Hospital, Houston, TX, United States.,Department of Neurosurgery, Houston Methodist Research Institute, Houston, TX, United States.,Department of Neurosurgery, Weill Cornell Medical College, New York, NY, United States
| | - Kumar Pichumani
- Kenneth R. Peak Center for Brain and Pituitary Tumor Treatment and Research, Houston Methodist Hospital, Houston, TX, United States.,Department of Neurosurgery, Houston Methodist Hospital, Houston, TX, United States.,Department of Neurosurgery, Houston Methodist Research Institute, Houston, TX, United States.,Department of Neurosurgery, Weill Cornell Medical College, New York, NY, United States
| | - Omkar B Ijare
- Kenneth R. Peak Center for Brain and Pituitary Tumor Treatment and Research, Houston Methodist Hospital, Houston, TX, United States.,Department of Neurosurgery, Houston Methodist Hospital, Houston, TX, United States.,Department of Neurosurgery, Houston Methodist Research Institute, Houston, TX, United States
| | - Santosh A Helekar
- Kenneth R. Peak Center for Brain and Pituitary Tumor Treatment and Research, Houston Methodist Hospital, Houston, TX, United States.,Department of Neurosurgery, Houston Methodist Hospital, Houston, TX, United States.,Department of Neurosurgery, Houston Methodist Research Institute, Houston, TX, United States.,Department of Neurosurgery, Weill Cornell Medical College, New York, NY, United States
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3
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Sharpe MA, Baskin DS, Jenson AV, Baskin AM. Hijacking Sexual Immuno-Privilege in GBM-An Immuno-Evasion Strategy. Int J Mol Sci 2021; 22:10983. [PMID: 34681642 PMCID: PMC8536168 DOI: 10.3390/ijms222010983] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Revised: 09/28/2021] [Accepted: 10/05/2021] [Indexed: 01/12/2023] Open
Abstract
Regulatory T-cells (Tregs) are immunosuppressive T-cells, which arrest immune responses to 'Self' tissues. Some immunosuppressive Tregs that recognize seminal epitopes suppress immune responses to the proteins in semen, in both men and women. We postulated that GBMs express reproductive-associated proteins to manipulate reproductive Tregs and to gain immune privilege. We analyzed four GBM transcriptome databases representing ≈900 tumors for hypoxia-responsive Tregs, steroidogenic pathways, and sperm/testicular and placenta-specific genes, stratifying tumors by expression. In silico analysis suggested that the presence of reproductive-associated Tregs in GBM tumors was associated with worse patient outcomes. These tumors have an androgenic signature, express male-specific antigens, and attract reproductive-associated Related Orphan Receptor C (RORC)-Treg immunosuppressive cells. GBM patient sera were interrogated for the presence of anti-sperm/testicular antibodies, along with age-matched controls, utilizing monkey testicle sections. GBM patient serum contained anti-sperm/testicular antibodies at levels > six-fold that of controls. Myeloid-derived suppressor cells (MDSCs) and tumor-associated macrophages (TAMs) are associated with estrogenic tumors which appear to mimic placental tissue. We demonstrate that RORC-Tregs drive poor patient outcome, and Treg infiltration correlates strongly with androgen levels. Androgens support GBM expression of sperm/testicular proteins allowing Tregs from the patient's reproductive system to infiltrate the tumor. In contrast, estrogen appears responsible for MDSC/TAM immunosuppression.
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MESH Headings
- Androgens/metabolism
- Brain Neoplasms/immunology
- Brain Neoplasms/mortality
- Brain Neoplasms/pathology
- Carrier Proteins/genetics
- Carrier Proteins/metabolism
- Databases, Factual
- Estrogens/metabolism
- Female
- Glioblastoma/immunology
- Glioblastoma/mortality
- Glioblastoma/pathology
- Humans
- Hypoxia-Inducible Factor 1, alpha Subunit/genetics
- Hypoxia-Inducible Factor 1, alpha Subunit/metabolism
- Kaplan-Meier Estimate
- Lymphocytes, Tumor-Infiltrating/immunology
- Lymphocytes, Tumor-Infiltrating/metabolism
- Male
- Microglia/immunology
- Microglia/metabolism
- Nuclear Receptor Subfamily 1, Group F, Member 3/genetics
- Nuclear Receptor Subfamily 1, Group F, Member 3/metabolism
- T-Lymphocytes, Regulatory/immunology
- T-Lymphocytes, Regulatory/metabolism
- Tumor Microenvironment
- Tumor-Associated Macrophages/immunology
- Tumor-Associated Macrophages/metabolism
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Affiliation(s)
- Martyn A. Sharpe
- Kenneth R. Peak Brain and Pituitary Tumor Treatment Center, Department of Neurosurgery, Houston Methodist Neurological Institute, Houston Methodist Hospital and Research Institute, Houston, TX 77030, USA; (D.S.B.); (A.V.J.); (A.M.B.)
| | - David S. Baskin
- Kenneth R. Peak Brain and Pituitary Tumor Treatment Center, Department of Neurosurgery, Houston Methodist Neurological Institute, Houston Methodist Hospital and Research Institute, Houston, TX 77030, USA; (D.S.B.); (A.V.J.); (A.M.B.)
- Department of Neurological Surgery, Weill Cornell Medical College, New York, NY 10065, USA
| | - Amanda V. Jenson
- Kenneth R. Peak Brain and Pituitary Tumor Treatment Center, Department of Neurosurgery, Houston Methodist Neurological Institute, Houston Methodist Hospital and Research Institute, Houston, TX 77030, USA; (D.S.B.); (A.V.J.); (A.M.B.)
| | - Alexandra M. Baskin
- Kenneth R. Peak Brain and Pituitary Tumor Treatment Center, Department of Neurosurgery, Houston Methodist Neurological Institute, Houston Methodist Hospital and Research Institute, Houston, TX 77030, USA; (D.S.B.); (A.V.J.); (A.M.B.)
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Ijare OB, Hambarde S, Brasil da Costa FH, Lopez S, Sharpe MA, Helekar SA, Hangel G, Bogner W, Widhalm G, Bachoo RM, Baskin DS, Pichumani K. Glutamine anaplerosis is required for amino acid biosynthesis in human meningiomas. Neuro Oncol 2021; 24:556-568. [PMID: 34515312 DOI: 10.1093/neuonc/noab219] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND We postulate that meningiomas undergo distinct metabolic reprogramming in tumorigenesis and unravelling their metabolic phenotypes provide new therapeutic insights. Glutamine catabolism is key to the growth and proliferation of tumors. Here, we investigated the metabolomics of freshly resected meningiomas and glutamine metabolism in patient-derived meningioma cells. METHODS 1H NMR spectroscopy of tumor tissues from 33 meningioma patients was used to differentiate the metabolite profiles of grade-I and grade-II meningiomas. Glutamine metabolism was examined using 13C/ 15N glutamine tracer, in five patient-derived meningioma cells. RESULTS Alanine, lactate, glutamate, glutamine, and glycine were predominantly elevated only in grade-II meningiomas by 74%, 76%, 35%, 75% and 33% respectively, with alanine, and glutamine being statistically significant (p ≤ 0.02). 13C/ 15N glutamine tracer experiments revealed that both grade-I and -II meningiomas actively metabolize glutamine to generate various key carbon intermediates including alanine and proline that are necessary for the tumor growth. Also, it is shown that glutaminase (GLS1) inhibitor, CB-839 is highly effective in downregulating glutamine metabolism and decreasing proliferation in meningioma cells. CONCLUSION Alanine and glutamine/glutamate are mainly elevated in grade-II meningiomas. Grade-I meningiomas possess relatively higher glutamine metabolism providing carbon/nitrogen for the biosynthesis of key nonessential amino acids. GLS1 inhibitor (CB-839) would be very effective in downregulating glutamine metabolic pathways in grade-I meningiomas leading to decreased cellular proliferation.
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Affiliation(s)
- Omkar B Ijare
- Kenneth R. Peak Brain and Pituitary Tumor Treatment Center, Department of Neurosurgery, Houston Methodist Neurological Institute, Houston Methodist Hospital and Research Institute, Houston, TX, USA
| | - Shashank Hambarde
- Kenneth R. Peak Brain and Pituitary Tumor Treatment Center, Department of Neurosurgery, Houston Methodist Neurological Institute, Houston Methodist Hospital and Research Institute, Houston, TX, USA
| | - Fabio Henrique Brasil da Costa
- Kenneth R. Peak Brain and Pituitary Tumor Treatment Center, Department of Neurosurgery, Houston Methodist Neurological Institute, Houston Methodist Hospital and Research Institute, Houston, TX, USA
| | - Sophie Lopez
- Kenneth R. Peak Brain and Pituitary Tumor Treatment Center, Department of Neurosurgery, Houston Methodist Neurological Institute, Houston Methodist Hospital and Research Institute, Houston, TX, USA
| | - Martyn A Sharpe
- Kenneth R. Peak Brain and Pituitary Tumor Treatment Center, Department of Neurosurgery, Houston Methodist Neurological Institute, Houston Methodist Hospital and Research Institute, Houston, TX, USA
| | - Santosh A Helekar
- Kenneth R. Peak Brain and Pituitary Tumor Treatment Center, Department of Neurosurgery, Houston Methodist Neurological Institute, Houston Methodist Hospital and Research Institute, Houston, TX, USA.,Weill Cornell Medical College, New York, NY, USA
| | - Gilbert Hangel
- High-field MR Center, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria.,Department of Neurosurgery, Medical University of Vienna, Vienna, Austria
| | - Wolfgang Bogner
- High-field MR Center, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria
| | - Georg Widhalm
- Department of Neurosurgery, Medical University of Vienna, Vienna, Austria
| | - Robert M Bachoo
- Department of Neurology and Neurotherapeutics, UT Southwestern Medical Center, Dallas, TX, USA
| | - David S Baskin
- Kenneth R. Peak Brain and Pituitary Tumor Treatment Center, Department of Neurosurgery, Houston Methodist Neurological Institute, Houston Methodist Hospital and Research Institute, Houston, TX, USA.,Weill Cornell Medical College, New York, NY, USA
| | - Kumar Pichumani
- Kenneth R. Peak Brain and Pituitary Tumor Treatment Center, Department of Neurosurgery, Houston Methodist Neurological Institute, Houston Methodist Hospital and Research Institute, Houston, TX, USA.,Weill Cornell Medical College, New York, NY, USA
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5
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Helekar SA, Hambarde S, Ijare OB, Pichumani K, Baskin DS, Sharpe MA. Selective induction of rapid cytotoxic effect in glioblastoma cells by oscillating magnetic fields. J Cancer Res Clin Oncol 2021; 147:3577-3589. [PMID: 34477946 DOI: 10.1007/s00432-021-03787-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [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: 07/24/2021] [Accepted: 08/28/2021] [Indexed: 01/03/2023]
Abstract
PURPOSE The mechanisms underlying anticancer effects of electromagnetic fields are poorly understood. An alternating electric field-generating therapeutic device called Optune™ device has been approved for the treatment of glioblastoma (GBM). We have developed a new device that generates oscillating magnetic fields (OMF) by rapid rotation of strong permanent magnets in specially designed patterns of frequency and timing and have used it to treat an end-stage recurrent GBM patient under an expanded access/compassionate use treatment protocol. Here, we ask whether OMF causes selective cytotoxic effects in GBM and whether it is through generation of reactive oxygen species (ROS). METHODS We stimulated patient derived GBM cells, lung cancer cells, normal human cortical neurons, astrocytes, and bronchial epithelial cells using OMF generators (oncoscillators) of our Oncomagnetic Device and compared the results to those obtained under unstimulated or sham-stimulated control conditions. Quantitative fluorescence microscopy was used to assess cell morphology, viability, and ROS production mechanisms. RESULTS We find that OMF induces highly selective cell death of patient derived GBM cells associated with activation of caspase 3, while leaving normal tissue cells undamaged. The cytotoxic effect of OMF is also seen in pulmonary cancer cells. The underlying mechanism is a marked increase in ROS in the mitochondria, possibly in part through perturbation of the electron flow in the respiratory chain. CONCLUSION Rotating magnetic fields produced by a new noninvasive device selectively kill cultured human glioblastoma and non-small cell lung cancer cells by raising intracellular reactive oxygen species, but not normal human tissue cells.
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Affiliation(s)
- Santosh A Helekar
- Kenneth R. Peak Center for Brain and Pituitary Tumor Treatment and Research, Houston Methodist Hospital, 6445 Main St., Floor 24, Houston, TX, 77030, USA.
- Department of Neurosurgery, Houston Methodist Hospital, Houston, TX, USA.
- Department of Neurosurgery, Houston Methodist Research Institute, Houston, TX, USA.
- Department of Neurosurgery, Weill Cornell Medical College, New York, NY, USA.
| | - Shashank Hambarde
- Kenneth R. Peak Center for Brain and Pituitary Tumor Treatment and Research, Houston Methodist Hospital, 6445 Main St., Floor 24, Houston, TX, 77030, USA
- Department of Neurosurgery, Houston Methodist Hospital, Houston, TX, USA
- Department of Neurosurgery, Houston Methodist Research Institute, Houston, TX, USA
| | - Omkar B Ijare
- Kenneth R. Peak Center for Brain and Pituitary Tumor Treatment and Research, Houston Methodist Hospital, 6445 Main St., Floor 24, Houston, TX, 77030, USA
- Department of Neurosurgery, Houston Methodist Hospital, Houston, TX, USA
- Department of Neurosurgery, Houston Methodist Research Institute, Houston, TX, USA
| | - Kumar Pichumani
- Kenneth R. Peak Center for Brain and Pituitary Tumor Treatment and Research, Houston Methodist Hospital, 6445 Main St., Floor 24, Houston, TX, 77030, USA
- Department of Neurosurgery, Houston Methodist Hospital, Houston, TX, USA
- Department of Neurosurgery, Houston Methodist Research Institute, Houston, TX, USA
- Department of Neurosurgery, Weill Cornell Medical College, New York, NY, USA
| | - David S Baskin
- Kenneth R. Peak Center for Brain and Pituitary Tumor Treatment and Research, Houston Methodist Hospital, 6445 Main St., Floor 24, Houston, TX, 77030, USA
- Department of Neurosurgery, Houston Methodist Hospital, Houston, TX, USA
- Department of Neurosurgery, Houston Methodist Research Institute, Houston, TX, USA
- Department of Neurosurgery, Weill Cornell Medical College, New York, NY, USA
| | - Martyn A Sharpe
- Kenneth R. Peak Center for Brain and Pituitary Tumor Treatment and Research, Houston Methodist Hospital, 6445 Main St., Floor 24, Houston, TX, 77030, USA
- Department of Neurosurgery, Houston Methodist Hospital, Houston, TX, USA
- Department of Neurosurgery, Houston Methodist Research Institute, Houston, TX, USA
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Baskin DS, Sharpe MA, Nguyen L, Helekar SA. Case Report: End-Stage Recurrent Glioblastoma Treated With a New Noninvasive Non-Contact Oncomagnetic Device. Front Oncol 2021; 11:708017. [PMID: 34367992 PMCID: PMC8341943 DOI: 10.3389/fonc.2021.708017] [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] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Accepted: 06/21/2021] [Indexed: 11/25/2022] Open
Abstract
Alternating electric field therapy has been approved for glioblastoma (GBM). We have preclinical evidence for anticancer effects in GBM cell cultures and mouse xenografts with an oscillating magnetic field (OMF) generating device. Here we report OMF treatment of end-stage recurrent glioblastoma in a 53-year-old man who had undergone radical surgical excision and chemoradiotherapy, and experimental gene therapy for a left frontal tumor. He experienced tumor recurrence and progressive enlargement with leptomeningeal involvement. OMF for 5 weeks was well tolerated, with 31% reduction of contrast-enhanced tumor volume and reduction in abnormal T2-weighted Fluid-Attenuated Inversion Recovery volume. Tumor shrinkage appeared to correlate with treatment dose. These findings suggest a powerful new noninvasive therapy for glioblastoma.
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Affiliation(s)
- David S Baskin
- Kenneth R. Peak Brain and Pituitary Tumor Treatment Center, Department of Neurosurgery, Houston Methodist Neurological Institute, Houston, TX, United States.,Department of Neurosurgery, Houston Methodist Research Institute, Houston, TX, United States.,Department of Neurosurgery, Weill Cornell Medical College, New York, NY, United States
| | - Martyn A Sharpe
- Kenneth R. Peak Brain and Pituitary Tumor Treatment Center, Department of Neurosurgery, Houston Methodist Neurological Institute, Houston, TX, United States.,Department of Neurosurgery, Houston Methodist Research Institute, Houston, TX, United States
| | - Lisa Nguyen
- Kenneth R. Peak Brain and Pituitary Tumor Treatment Center, Department of Neurosurgery, Houston Methodist Neurological Institute, Houston, TX, United States.,Department of Neurosurgery, Houston Methodist Research Institute, Houston, TX, United States
| | - Santosh A Helekar
- Kenneth R. Peak Brain and Pituitary Tumor Treatment Center, Department of Neurosurgery, Houston Methodist Neurological Institute, Houston, TX, United States.,Department of Neurosurgery, Houston Methodist Research Institute, Houston, TX, United States.,Department of Neurosurgery, Weill Cornell Medical College, New York, NY, United States
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Raghavan S, Baskin DS, Sharpe MA. MP-Pt(IV): A MAOB-Sensitive Mitochondrial-Specific Prodrug for Treating Glioblastoma. Mol Cancer Ther 2020; 19:2445-2453. [PMID: 33033175 DOI: 10.1158/1535-7163.mct-20-0420] [Citation(s) in RCA: 4] [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] [Received: 05/18/2020] [Revised: 08/13/2020] [Accepted: 09/23/2020] [Indexed: 11/16/2022]
Abstract
We have previously reported the in vitro and in vivo efficacy of N,N-bis(2-chloroethyl)-2-(1-methyl-1,2,3,6-tetrahydropyridin-4-yl)propenamide (MP-MUS), a prodrug that targeted the mitochondria of glioblastoma (GBM). The mitochondrial enzyme, monoamine oxidase B (MAOB), is highly expressed in GBM and oxidizes an uncharged methyl-tetrahydropyridine (MP-) moiety into the mitochondrially targeted cationic form, methyl-pyridinium (P+-). Coupling this MAOB-sensitive group to a nitrogen mustard produced a prodrug that damaged GBM mitochondria and killed GBM cells. Unfortunately, the intrinsic reactivity of the nitrogen mustard group and low solubility of MP-MUS precluded clinical development. In our second-generation prodrug, MP-Pt(IV), we coupled the MP group to an unreactive cisplatin precursor. The enzymatic conversion of MP-Pt(IV) to P+-Pt(IV) was tested using recombinant human MAOA and rhMAOB. The generation of cisplatin from Pt(IV) by ascorbate was studied optically and using mass spectroscopy. Efficacy toward primary GBM cells and tumors was studied in vitro and in an intracranial patient-derived xenograft mice GBM model. Our studies demonstrate that MP-Pt(IV) is selectively activated by MAOB. MP-Pt(IV) is highly toxic toward GBM cells in vitro MP-Pt(IV) toxicity against GBM is potentiated by elevating mitochondrial ascorbate and can be arrested by MAOB inhibition. In in vitro studies, sublethal MP-Pt(IV) doses elevated mitochondrial MAOB levels in surviving GBM cells. MP-Pt(IV) is a potent chemotherapeutic in intracranial patient-derived xenograft mouse models of primary GBM and potentiates both temozolomide and temozolomide-chemoradiation therapies. MP-Pt(IV) was well tolerated and is highly effective against GBM in both in vitro and in vivo models.
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Affiliation(s)
- Sudhir Raghavan
- Kenneth R. Peak Brain and Pituitary Treatment Center and the Department of Neurosurgery, Houston Methodist Hospital, Houston, Texas.,Houston Methodist Research Institute, Houston, Texas
| | - David S Baskin
- Kenneth R. Peak Brain and Pituitary Treatment Center and the Department of Neurosurgery, Houston Methodist Hospital, Houston, Texas. .,Houston Methodist Research Institute, Houston, Texas
| | - Martyn A Sharpe
- Kenneth R. Peak Brain and Pituitary Treatment Center and the Department of Neurosurgery, Houston Methodist Hospital, Houston, Texas. .,Houston Methodist Research Institute, Houston, Texas
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8
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Raghavan S, Baskin DS, Sharpe MA. A "Clickable" Probe for Active MGMT in Glioblastoma Demonstrates Two Discrete Populations of MGMT. Cancers (Basel) 2020; 12:cancers12020453. [PMID: 32075134 PMCID: PMC7072665 DOI: 10.3390/cancers12020453] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [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: 01/15/2020] [Revised: 02/04/2020] [Accepted: 02/10/2020] [Indexed: 01/19/2023] Open
Abstract
Various pathways can repair DNA alkylation by chemotherapeutic agents such as temozolomide (TMZ). The enzyme O6-methylguanine methyltransferase (MGMT) removes O6-methylated DNA adducts, leading to the failure of chemotherapy in resistant glioblastomas. Because of the anti-chemotherapeutic activities of MGMT previously described, estimating the levels of active MGMT in cancer cells can be a significant predictor of response to alkylating agents. Current methods to detect MGMT in cells are indirect, complicated, time-intensive, or utilize molecules that require complex and multistep chemistry synthesis. Our design simulates DNA repair by the transfer of a clickable propargyl group from O6-propargyl guanine to active MGMT and subsequent attachment of fluorescein-linked PEG linker via "click chemistry." Visualization of active MGMT levels reveals discrete active and inactive MGMT populations with biphasic kinetics for MGMT inactivation in response to TMZ-induced DNA damage.
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Affiliation(s)
- Sudhir Raghavan
- Correspondence: (S.R.); (M.A.S.); Tel.: +1-713-441-8822 (S.R.); +1-713-363-6995 (M.A.S.)
| | | | - Martyn A. Sharpe
- Correspondence: (S.R.); (M.A.S.); Tel.: +1-713-441-8822 (S.R.); +1-713-363-6995 (M.A.S.)
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9
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Ijare OB, Holan C, Hebert J, Sharpe MA, Baskin DS, Pichumani K. Elevated levels of circulating betahydroxybutyrate in pituitary tumor patients may differentiate prolactinomas from other immunohistochemical subtypes. Sci Rep 2020; 10:1334. [PMID: 31992791 PMCID: PMC6987215 DOI: 10.1038/s41598-020-58244-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [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: 09/09/2019] [Accepted: 01/06/2020] [Indexed: 01/12/2023] Open
Abstract
The diagnosis of various histological subtypes of pituitary tumors is made using serum based hormone panel test. However, certain subtypes secrete more than one hormone, making the diagnosis ambiguous. Here, we performed 1H-NMR based metabolomic analysis of serum and whole-blood from luteinizing/follicle-stimulating (LH/FSH)-secreting (n = 24), prolactinomas (n = 14), and non-functional (NF) (n = 9) tumors. We found elevated levels of betahydroxybutyrate (BHB) in serum and whole-blood (WB) of prolactinomas (0.481 ± 0.211/0.329 ± 0.228 mM in serum/WB), but it was statistically significant (p ≤ 0.0033, Bonferroni correction) only in serum when compared with LH/FSH-secreting tumor patients (0.269 ± 0.139/0.167 ± 0.113 mM in serum/WB). Phenylalanine in NF tumors was found to be elevated in both serum and WB when compared with prolactinomas but it met the statistical significance criteria (p ≤ 0.0028) only in the serum. Alanine (p ≤ 0.011), tyrosine (p ≤ 0.014) and formate (p ≤ 0.011) were also elevated in NF tumors but none showed statistically significance when compared with prolactinomas. Quantification of BHB and the above amino acids in the circulation may aid in the development of blood-based in vitro diagnostic methods which can supplement the currently used serum hormone panel in the diagnosis of various subtypes of pituitary tumors.
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Affiliation(s)
- Omkar B Ijare
- Kenneth R. Peak Brain and Pituitary Tumor Treatment Center, Department of Neurosurgery, Houston Methodist Neurological Institute, Houston Methodist Hospital and Research Institute, Houston, TX, USA
| | - Cole Holan
- Kenneth R. Peak Brain and Pituitary Tumor Treatment Center, Department of Neurosurgery, Houston Methodist Neurological Institute, Houston Methodist Hospital and Research Institute, Houston, TX, USA
| | - Jonathan Hebert
- Kenneth R. Peak Brain and Pituitary Tumor Treatment Center, Department of Neurosurgery, Houston Methodist Neurological Institute, Houston Methodist Hospital and Research Institute, Houston, TX, USA
| | - Martyn A Sharpe
- Kenneth R. Peak Brain and Pituitary Tumor Treatment Center, Department of Neurosurgery, Houston Methodist Neurological Institute, Houston Methodist Hospital and Research Institute, Houston, TX, USA
| | - David S Baskin
- Kenneth R. Peak Brain and Pituitary Tumor Treatment Center, Department of Neurosurgery, Houston Methodist Neurological Institute, Houston Methodist Hospital and Research Institute, Houston, TX, USA.,Weill Cornell Medical College, New York, NY, USA
| | - Kumar Pichumani
- Kenneth R. Peak Brain and Pituitary Tumor Treatment Center, Department of Neurosurgery, Houston Methodist Neurological Institute, Houston Methodist Hospital and Research Institute, Houston, TX, USA. .,Weill Cornell Medical College, New York, NY, USA.
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Golanov EV, Sharpe MA, Regnier-Golanov AS, Del Zoppo GJ, Baskin DS, Britz GW. Fibrinogen Chains Intrinsic to the Brain. Front Neurosci 2019; 13:541. [PMID: 31191233 PMCID: PMC6549596 DOI: 10.3389/fnins.2019.00541] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [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: 04/01/2019] [Accepted: 05/09/2019] [Indexed: 11/13/2022] Open
Abstract
We observed fine fibrin deposition along the paravascular spaces in naive animals, which increased dramatically following subarachnoid hemorrhage (SAH). Following SAH, fibrin deposits in the areas remote from the hemorrhage. Traditionally it is thought that fibrinogen enters subarachnoid space through damaged blood brain barrier. However, deposition of fibrin remotely from hemorrhage suggests that fibrinogen chains Aα, Bβ, and γ can originate in the brain. Here we demonstrate in vivo and in vitro that astroglia and neurons are capable of expression of fibrinogen chains. SAH in mice was induced by the filament perforation of the circle of Willis. Four days after SAH animals were anesthetized, transcardially perfused and fixed. Whole brain was processed for immunofluorescent (IF) analysis of fibrin deposition on the brain surface or in brains slices processed for fibrinogen chains Aα, Bβ, γ immunohistochemical detection. Normal human astrocytes were grown media to confluency and stimulated with NOC-18 (100 μM), TNF-α (100 nM), ATP-γ-S (100 μM) for 24 h. Culture was fixed and washed/permeabilized with 0.1% Triton and processed for IF. Four days following SAH fibrinogen chains Aα IF associated with glia limitans and superficial brain layers increased 3.2 and 2.5 times (p < 0.05 and p < 0.01) on the ventral and dorsal brain surfaces respectively; fibrinogen chains Bβ increased by 3 times (p < 0.01) on the dorsal surface and fibrinogen chain γ increased by 3 times (p < 0.01) on the ventral surface compared to sham animals. Human cultured astrocytes and neurons constitutively expressed all three fibrinogen chains. Their expression changed differentially when exposed for 24 h to biologically significant stimuli: TNFα, NO or ATP. Western blot and RT-qPCR confirmed presence of the products of the appropriate molecular weight and respective mRNA. We demonstrate for the first time that mouse and human astrocytes and neurons express fibrinogen chains suggesting potential presence of endogenous to the brain fibrinogen chains differentially changing to biologically significant stimuli. SAH is followed by increased expression of fibrinogen chains associated with glia limitans remote from the hemorrhage. We conclude that brain astrocytes and neurons are capable of production of fibrinogen chains, which may be involved in various normal and pathological processes.
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Affiliation(s)
- Eugene V Golanov
- Department of Neurosurgery, Houston Methodist Hospital, Houston, TX, United States
| | - Martyn A Sharpe
- Department of Neurosurgery, Houston Methodist Hospital, Houston, TX, United States
| | | | - Gregory J Del Zoppo
- Division of Hematology, University of Washington School of Medicine, Seattle, WA, United States
| | - David S Baskin
- Department of Neurosurgery, Houston Methodist Hospital, Houston, TX, United States
| | - Gavin W Britz
- Department of Neurosurgery, Houston Methodist Hospital, Houston, TX, United States
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Sharpe MA, Raghavan S, Baskin DS. PAM-OBG: A monoamine oxidase B specific prodrug that inhibits MGMT and generates DNA interstrand crosslinks, potentiating temozolomide and chemoradiation therapy in intracranial glioblastoma. Oncotarget 2018; 9:23923-23943. [PMID: 29844863 PMCID: PMC5963626 DOI: 10.18632/oncotarget.25246] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [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: 02/07/2018] [Accepted: 04/08/2018] [Indexed: 12/31/2022] Open
Abstract
Via extensive analyses of genetic databases, we have characterized the DNA-repair capacity of glioblastoma with respect to patient survival. In addition to elevation of O6-methylguanine DNA methyltransferase (MGMT), down-regulation of three DNA repair pathways; canonical mismatch repair (MMR), Non-Homologous End-Joining (NHEJ), and Homologous Recombination (HR) are correlated with poor patient outcome. We have designed and tested both in vitro and in vivo, a monoamine oxidase B (MAOB) specific prodrug, PAM-OBG, that is converted by glioma MAOB into the MGMT inhibitor O6-benzylguanine (O6BG) and the DNA crosslinking agent acrolein. In cultured glioma cells, we show that PAM-OBG is converted to O6BG, inhibiting MGMT and sensitizing cells to DNA alkylating agents such as BCNU, CCNU, and Temozolomide (TMZ). In addition, we demonstrate that the acrolein generated is highly toxic in glioma treated with an inhibitor of Nucleotide Excision Repair (NER). In mouse intracranial models of primary human glioma, we show that PAM-OBG increases survival of mice treated with either BCNU or CCNU by a factor of six and that in a chemoradiation model utilizing six rounds of TMZ/2Gy radiation, pre-treatment with PAM-OBG more than doubled survival time.
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Affiliation(s)
- Martyn A Sharpe
- Department of Neurosurgery, Kenneth R. Peak Brain and Pituitary Tumor Center, Houston Methodist Hospital, TX 77030, Houston, USA
| | - Sudhir Raghavan
- Department of Neurosurgery, Kenneth R. Peak Brain and Pituitary Tumor Center, Houston Methodist Hospital, TX 77030, Houston, USA
| | - David S Baskin
- Department of Neurosurgery, Kenneth R. Peak Brain and Pituitary Tumor Center, Houston Methodist Hospital, TX 77030, Houston, USA
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12
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Ijare OB, Baskin DS, Sharpe MA, Pichumani K. Metabolism of fructose in B-cells: A 13C NMR spectroscopy based stable isotope tracer study. Anal Biochem 2018; 552:110-117. [PMID: 29654744 DOI: 10.1016/j.ab.2018.04.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2018] [Revised: 03/12/2018] [Accepted: 04/06/2018] [Indexed: 12/27/2022]
Abstract
Earlier studies on glucose metabolism in B-cells suggested an active TCA cycle in both naïve B cells and differentiated IgA plasma cells. Glycolysis was shown to be more active in IgA plasma cells than naïve B-cells. There have been no reports on the metabolism of fructose in B-cells. Fructose is a major sugar present in the western diet. Thus, we have investigated the metabolism of fructose in B-cells including the effect of glucose on the metabolism of fructose. In this study, using 13C NMR spectroscopy and [U-13C]fructose and [U-13C]glucose as stable 13C isotope tracers, we investigated the metabolic fate of fructose and glucose in B-cells. B-cells showed mitochondrial oxidation of fructose when administered alone, but showed diminished oxidation of fructose in the presence of glucose. On the other hand, fructose did not significantly affect the mitochondrial metabolism of glucose.
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Affiliation(s)
- Omkar B Ijare
- Kenneth R. Peak Brain and Pituitary Tumor Treatment Center, Department of Neurosurgery, Houston Methodist Neurological Institute, Houston Methodist Hospital and Research Institute, Houston, TX, 77030, USA
| | - David S Baskin
- Kenneth R. Peak Brain and Pituitary Tumor Treatment Center, Department of Neurosurgery, Houston Methodist Neurological Institute, Houston Methodist Hospital and Research Institute, Houston, TX, 77030, USA; Weill Cornell Medical College, New York, NY, USA
| | - Martyn A Sharpe
- Kenneth R. Peak Brain and Pituitary Tumor Treatment Center, Department of Neurosurgery, Houston Methodist Neurological Institute, Houston Methodist Hospital and Research Institute, Houston, TX, 77030, USA.
| | - Kumar Pichumani
- Kenneth R. Peak Brain and Pituitary Tumor Treatment Center, Department of Neurosurgery, Houston Methodist Neurological Institute, Houston Methodist Hospital and Research Institute, Houston, TX, 77030, USA; Weill Cornell Medical College, New York, NY, USA.
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13
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Abstract
Selective targeting of drug loaded nanovectors to specific epitopes highly expressed on the surface of cancer cells is a goal for nanotechnologists. We have modified our previously described PEGylated-hydrophilic carbon clusters (PEG-HCCs) so that the epidermal growth factor receptor (EGFR) binding peptide, GE11, is attached using click chemistry at the end of each PEG. The resulting nanosyringe, PepEGFR-PEG-HCC, can be loaded with a wide range of hydrophobic drugs and dyes. We show that, both in vitro and in vivo, this payload can be delivered to cancer cells expressing EGFR. We can observe the activation of EGFR and track the normal physiological internalization and recycling/signaling pathways of this tyrosine kinase following binding of PepEGFR-PEG-HCC. We also demonstrate the competitive binding of the nanosyringe to EGFR with its normal activator, EGF, as well as observing the colocalization of the nanosyringe with clathrin, the coated pit integral protein. The internalization of the drug/dye loaded nanosyringe can be inhibited by using anti-EGFR antibodies, the drug erlotinib, or Pitstop-1, the clathrin coated pit formation specific inhibitor. To further demonstrate the specificity of the drug loaded nanovectors, we demonstrated that, in both flank and intracranial xenograft mouse models, dye delivery is highly specific to tumors and no other tissues. Finally, using nanosyringes loaded with esterase sensitive fluorescein diacetate, we demonstrated that the drug payloads can be in vivo delivered to the cytosol of cancer cells within the mouse brain.
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Affiliation(s)
| | - Melissa Singh
- Fannin Innovation Studio, 3900
Essex Lane, Suite 575, Houston, Texas 77027, United States
| | - David S. Baskin
- Kenneth
R. Peak Brain and Pituitary Tumor Center, Department of Neurosurgery, Houston Methodist Hospital, Houston, Texas 77030, United States
| | | | - Martyn A. Sharpe
- Kenneth
R. Peak Brain and Pituitary Tumor Center, Department of Neurosurgery, Houston Methodist Hospital, Houston, Texas 77030, United States
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14
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15
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Sharpe MA, Baskin DS. Monoamine oxidase B levels are highly expressed in human gliomas and are correlated with the expression of HiF-1α and with transcription factors Sp1 and Sp3. Oncotarget 2016; 7:3379-93. [PMID: 26689994 PMCID: PMC4823113 DOI: 10.18632/oncotarget.6582] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [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: 08/14/2015] [Accepted: 11/16/2015] [Indexed: 11/25/2022] Open
Abstract
Monoamine oxidases A and B (MAOA and MAOB) are highly expressed in many cancers. Here we investigated the level of MAOB in gliomas and confirmed its high expression. We found that MAOB levels correlated with tumor grade and hypoxia-inducible factor 1-alpha (HiF-1α) expression. HiF-1α was localized to the nuclei in high-grade gliomas, but it was primarily cytosolic in low-grade gliomas and normal human astrocytes. Expression of both glial fibrillary acidic protein (GFAP) and MAOB are correlated to HiF-1α expression levels. Levels of MAOB are correlated by the levels of transcription factor Sp3 in the majority of GBM examined, but this control of MAOB expression by Sp3 in low grade astrocytic gliomas is significantly different from control in the in the majority of glioblastomas. The current findings support previous suggestions that MAOB can be exploited for the killing of cancer cells. Selective cell toxicity can be achieved by designing non-toxic prodrugs that require MAOB for their catalytic conversion into mature cytotoxic chemotherapeutics.
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Affiliation(s)
- Martyn A Sharpe
- Department of Neurosurgery, Kenneth R. Peak Brain and Pituitary Tumor Center, Houston Methodist Hospital, Houston, TX 77030, USA
| | - David S Baskin
- Department of Neurosurgery, Kenneth R. Peak Brain and Pituitary Tumor Center, Houston Methodist Hospital, Houston, TX 77030, USA
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16
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Sharpe MA, Han J, Baskin AM, Baskin DS. Cover Picture: Design and Synthesis of a MAO-B-Selectively Activated Prodrug Based on MPTP: A Mitochondria-Targeting Chemotherapeutic Agent for Treatment of Human Malignant Gliomas (ChemMedChem 4/2015). ChemMedChem 2015. [DOI: 10.1002/cmdc.201590007] [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: 11/10/2022]
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Sharpe MA, Han J, Baskin AM, Baskin DS. Design and synthesis of a MAO-B-selectively activated prodrug based on MPTP: a mitochondria-targeting chemotherapeutic agent for treatment of human malignant gliomas. ChemMedChem 2015; 10:621-8. [PMID: 25677185 DOI: 10.1002/cmdc.201402562] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2014] [Indexed: 01/04/2023]
Abstract
Malignant gliomas, including glioblastomas, are extremely difficult to treat. The median survival for glioblastoma patients with optimal therapeutic intervention is 15 months. We developed a novel MAO-B-selectively activated prodrug, N,N-bis(2-chloroethyl)-2-(1-methyl-1,2,3,6-tetrahydropyridin-4-yl)propanamide (MP-MUS), for the treatment of gliomas based on 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). The design of neutral MP-MUS involved the use of a seeker molecule capable of binding to mitochondrial MAO-B, which is up-regulated ≥fourfold in glioma cells. Once the binding occurs, MP-MUS is converted into a positively charged moiety, P(+) -MUS, which accumulates inside mitochondria at a theoretical maximal value of 1000:1 gradient. The LD50 of MP-MUS against glioma cells is 75 μM, which is two- to threefold more potent than temozolomide, a primary drug for gliomas. Importantly, MP-MUS was found to be selectively toxic toward glioma cells. In the concentration range of 150-180 μM MP-MUS killed 90-95 % of glioma cells, but stimulated the growth of normal human astrocytes. Moreover, maturation of MP-MUS is highly dependent on MAO-B, and inhibition of MAO-B activity with selegiline protected human glioma cells from apoptosis.
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Affiliation(s)
- Martyn A Sharpe
- Kenneth R. Peak Brain and Pituitary Tumor Center, Department of Neurological Surgery, Neurological Institute, Houston Methodist Hospital, Weill Cornell Medical College of Cornell University, 6565 Fannin Street, Houston, TX, 77030 (USA)
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18
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Tsouko E, Khan AS, White MA, Han JJ, Shi Y, Merchant FA, Sharpe MA, Xin L, Frigo DE. Regulation of the pentose phosphate pathway by an androgen receptor-mTOR-mediated mechanism and its role in prostate cancer cell growth. Oncogenesis 2014; 3:e103. [PMID: 24861463 PMCID: PMC4035695 DOI: 10.1038/oncsis.2014.18] [Citation(s) in RCA: 97] [Impact Index Per Article: 9.7] [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: 03/27/2014] [Accepted: 04/23/2014] [Indexed: 12/11/2022] Open
Abstract
Cancer cells display an increased demand for glucose. Therefore, identifying the specific aspects of glucose metabolism that are involved in the pathogenesis of cancer may uncover novel therapeutic nodes. Recently, there has been a renewed interest in the role of the pentose phosphate pathway in cancer. This metabolic pathway is advantageous for rapidly growing cells because it provides nucleotide precursors and helps regenerate the reducing agent NADPH, which can contribute to reactive oxygen species (ROS) scavenging. Correspondingly, clinical data suggest glucose-6-phosphate dehydrogenase (G6PD), the rate-limiting enzyme of the pentose phosphate pathway, is upregulated in prostate cancer. We hypothesized that androgen receptor (AR) signaling, which plays an essential role in the disease, mediated prostate cancer cell growth in part by increasing flux through the pentose phosphate pathway. Here, we determined that G6PD, NADPH and ribose synthesis were all increased by AR signaling. Further, this process was necessary to modulate ROS levels. Pharmacological or molecular inhibition of G6PD abolished these effects and blocked androgen-mediated cell growth. Mechanistically, regulation of G6PD via AR in both hormone-sensitive and castration-resistant models of prostate cancer was abolished following rapamycin treatment, indicating that AR increased flux through the pentose phosphate pathway by the mammalian target of rapamycin (mTOR)-mediated upregulation of G6PD. Accordingly, in two separate mouse models of Pten deletion/elevated mTOR signaling, Pb-Cre;Pten(f/f) and K8-CreER(T2);Pten(f/f), G6PD levels correlated with prostate cancer progression in vivo. Importantly, G6PD levels remained high during progression to castration-resistant prostate cancer. Taken together, our data suggest that AR signaling can promote prostate cancer through the upregulation of G6PD and therefore, the flux of sugars through the pentose phosphate pathway. Hence, these findings support a vital role for other metabolic pathways (that is, not glycolysis) in prostate cancer cell growth and maintenance.
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Affiliation(s)
- E Tsouko
- Center for Nuclear Receptors and Cell Signaling, Department of Biology and Biochemistry, University of Houston, Houston, TX, USA
| | - A S Khan
- Center for Nuclear Receptors and Cell Signaling, Department of Biology and Biochemistry, University of Houston, Houston, TX, USA
| | - M A White
- Center for Nuclear Receptors and Cell Signaling, Department of Biology and Biochemistry, University of Houston, Houston, TX, USA
| | - J J Han
- Center for Nuclear Receptors and Cell Signaling, Department of Biology and Biochemistry, University of Houston, Houston, TX, USA
| | - Y Shi
- Center for Nuclear Receptors and Cell Signaling, Department of Biology and Biochemistry, University of Houston, Houston, TX, USA
| | - F A Merchant
- Department of Engineering Technology, University of Houston, Houston, TX, USA
| | - M A Sharpe
- Department of Neurosurgery, Houston Methodist Research Institute, Houston, TX, USA
| | - L Xin
- 1] Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX, USA [2] Department of Pathology and Immunology, Baylor College of Medicine, Houston, TX, USA [3] Dan L. Duncan Cancer Center, Houston, TX, USA
| | - D E Frigo
- 1] Center for Nuclear Receptors and Cell Signaling, Department of Biology and Biochemistry, University of Houston, Houston, TX, USA [2] Center for Genomic Medicine, Houston Methodist Research Institute, Houston, TX, USA
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19
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Sharpe MA, Marcano DC, Berlin JM, Widmayer MA, Baskin DS, Tour JM. Antibody-targeted nanovectors for the treatment of brain cancers. ACS Nano 2012; 6:3114-3120. [PMID: 22390360 DOI: 10.1021/nn2048679] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Introduced here is the hydrophilic carbon clusters (HCCs) antibody drug enhancement system (HADES), a methodology for cell-specific drug delivery. Antigen-targeted, drug-delivering nanovectors are manufactured by combining specific antibodies with drug-loaded poly(ethylene glycol)-HCCs (PEG-HCCs). We show that HADES is highly modular, as both the drug and antibody component can be varied for selective killing of a range of cultured human primary glioblastoma multiforme. Using three different chemotherapeutics and three different antibodies, without the need for covalent bonding to the nanovector, we demonstrate extreme lethality toward glioma, but minimal toxicity toward human astrocytes and neurons.
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Affiliation(s)
- Martyn A Sharpe
- Department of Neurosurgery, Methodist Hospital, 6560 Fannin Street, Houston, Texas 77030, United States.
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20
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Katsoulieris E, Mabley JG, Samai M, Sharpe MA, Green IC, Chatterjee PK. Lipotoxicity in renal proximal tubular cells: relationship between endoplasmic reticulum stress and oxidative stress pathways. Free Radic Biol Med 2010; 48:1654-62. [PMID: 20363316 DOI: 10.1016/j.freeradbiomed.2010.03.021] [Citation(s) in RCA: 48] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/30/2009] [Revised: 03/22/2010] [Accepted: 03/23/2010] [Indexed: 11/29/2022]
Abstract
Hyperlipidemia in the general population has been linked to the development of chronic kidney disease with both oxidative and endoplasmic reticulum stress implicated. Physiological levels (50-300 micromol/L) of saturated fatty acids such as palmitic acid (PA) cause cytotoxicity in vitro. We investigated cell type- and stimulus-specific signaling pathways induced by PA in renal proximal tubular cells and whether oxidative stress leads to ER stress or vice versa and which pathways predominate in signaling for PA-induced apoptosis and necrosis. NRK-52E cells were incubated with PA or hydrogen peroxide (H(2)O(2)) combined with SP600125 which blocks c-Jun N-terminal kinase (JNK) activation; salubrinal, which maintains eukaryotic initiation factor 2 alpha in its phosphorylated state and the antioxidant EUK-134 - a superoxide dismutase mimetic with catalase activity. We found that (i) PA causes both oxidative and ER stress leading to apoptosis which is mediated by phosphorylated JNK; (ii) oxidant-induced apoptosis generated by H(2)O(2) involves ER stress signaling and CHOP expression; (iii) the ER stress mediated by PA is largely independent of oxidative stress; (iv) in contrast, the apoptosis produced by PA is mediated partly via oxidative stress. PA-mediated cell signaling in renal NRK-52E cells therefore differs from that identified in neuronal, hepatic and pancreatic beta cells.
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Affiliation(s)
- Elias Katsoulieris
- Renal Research Group, Centre for Biomedical and Health Science Research, School of Pharmacy and Biomolecular Sciences, University of Brighton, UK
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21
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Baskin DS, Widmayer MA, Sharpe MA. Quantification and calibration of images in fluorescence microscopy. Anal Biochem 2010; 404:118-26. [PMID: 20513437 DOI: 10.1016/j.ab.2010.05.029] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2009] [Revised: 05/20/2010] [Accepted: 05/26/2010] [Indexed: 10/19/2022]
Abstract
Fluorescence microscopy is a method widely used in life sciences to image biological processes in living and fixed cells or in fixed tissues. Quantification and calibration of images in fluorescence microscopy is notoriously difficult. We have developed a new methodology to prepare tissue "phantoms" that contain known amounts of (i) fluorophore, (ii) DNA, (iii) proteins, and (iv) DNA oligonucleotide standards. The basis of the phantoms is the ability of gelatin to act as a matrix for the conjugation of fluorophores as either a free-flowing liquid or a gelatinous solid depending on temperature (> or = 40 and < or = 4 degrees C).
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Affiliation(s)
- David S Baskin
- Department of Neurosurgery, Methodist Hospital, Houston, TX 77030, USA
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22
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Sharpe MA, Krzyaniak MD, Xu S, McCracken J, Ferguson-Miller S. EPR evidence of cyanide binding to the Mn(Mg) center of cytochrome c oxidase: support for Cu(A)-Mg involvement in proton pumping. Biochemistry 2009; 48:328-35. [PMID: 19108635 DOI: 10.1021/bi801391r] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We examined the anion binding behavior of the Mg(Mn) site in cytochrome c oxidase to test a possible role of this center in proton pumping. Rhodobacter sphaeroides grown in a Mn(II)-rich medium replaces the intrinsic Mg(II) ion with an EPR-detectable Mn(II) ion without change in activity. Due to its close proximity and a shared ligand, oxidized Cu(A) is spin-coupled to the Mn(II) ion, affecting the EPR spectrum. An examination of both bovine and R.s. oxidase crystal structures reveals a hydrogen-bonding pattern in the vicinity of the Mg(II) site that is consistent with three water ligands of the Mg(Mn) center when Cu(A) is oxidized. In the reduced structure, one water molecule in the vicinity of the Cu(A) ligand, E198, moves closer, appearing to be converted into an ionically bonded hydronium ion, while a second water molecule bonded to Mg(Mn) shows evidence of conversion to a hydroxide. The implied proton movement is proposed to be part of a redox-linked export of a pumped proton from the binuclear center into the exit pathway. To test the model, cyanide and azide were added to the oxidized and reduced forms of the enzyme, and Mn(II) CW-EPR and ESEEM spectra were recorded. Addition of azide broadened the CW-EPR spectra for both oxidized and reduced enzyme. Cyanide addition affected the Mn(II) CW-EPR spectrum of reduced cytochrome c oxidase by increasing Mn(II) zero field splitting and broadening the spectral line shapes but had no effect on oxidized enzyme. ESEEM measurements support a differential ability of Mn(II) to bind cyanide in the reduced state of cytochrome c oxidase. This new observation of anion binding at the Mg/Mn site is of interest in terms of accessibility of the buried site and its potential role in redox-dependent proton pumping.
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Affiliation(s)
- Martyn A Sharpe
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan 48824-1319, USA.
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23
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Mills DA, Xu S, Geren L, Hiser C, Qin L, Sharpe MA, McCracken J, Durham B, Millett F, Ferguson-Miller S. Proton-dependent electron transfer from CuA to heme a and altered EPR spectra in mutants close to heme a of cytochrome oxidase. Biochemistry 2008; 47:11499-509. [PMID: 18847227 PMCID: PMC2659347 DOI: 10.1021/bi801156s] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Eukaryotic cytochrome c oxidase (CcO) and homologous prokaryotic forms of Rhodobacter and Paraccocus differ in the EPR spectrum of heme a. It was noted that a histidine ligand of heme a (H102) is hydrogen bonded to serine in Rhodobacter (S44) and Paraccocus CcOs, in contrast to glycine in the bovine enzyme. Mutation of S44 to glycine shifts the heme a EPR signal from g(z) = 2.82 to 2.86, closer to bovine heme a at 3.03, without modifying other properties. Mutation to aspartate, however, results in an oppositely shifted and split heme a EPR signal of g(z) = 2.72/2.78, accompanied by lower activity and drastically inhibited intrinsic electron transfer from CuA to heme a. This intrinsic rate is biphasic; the proportion that is slow is pH dependent, as is the relative intensity of the two EPR signal components. At pH 8, the heme a EPR signal at 2.72 is most intense, and the electron transfer rate (CuA to heme a) is 10-130 s(-1), compared to wild-type at 90,000 s(-1). At pH 5.5, the signal at 2.78 is intensified, and a biphasic rate is observed, 50% fast (approximately wild type) and 50% slow (90 s(-1)). The data support the prediction that the hydrogen-bonding partner of the histidine ligand of heme a is one determinant of the EPR spectral difference between bovine and bacterial CcO. We further demonstrate that the heme a redox potential can be dramatically altered by a nearby carboxyl, whose protonation leads to a proton-coupled electron transfer process.
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Affiliation(s)
- Denise A. Mills
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan 48824
| | - Shujuan Xu
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824
| | - Lois Geren
- Department of Chemistry and Biochemistry, University of Arkansas, Fayetteville, Arkansas 72701
| | - Carrie Hiser
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan 48824
| | - Ling Qin
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan 48824
| | - Martyn A. Sharpe
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan 48824
| | - John McCracken
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824
| | - Bill Durham
- Department of Chemistry and Biochemistry, University of Arkansas, Fayetteville, Arkansas 72701
| | - Francis Millett
- Department of Chemistry and Biochemistry, University of Arkansas, Fayetteville, Arkansas 72701
| | - Shelagh Ferguson-Miller
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan 48824
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Sharpe MA, Ferguson-Miller S. A chemically explicit model for the mechanism of proton pumping in heme-copper oxidases. J Bioenerg Biomembr 2008; 40:541-9. [PMID: 18830692 DOI: 10.1007/s10863-008-9182-6] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2008] [Accepted: 09/01/2008] [Indexed: 11/28/2022]
Abstract
A mechanism for proton pumping is described that is based on chemiosmotic principles and the detailed molecular structures now available for cytochrome oxidases. The importance of conserved water positions and a step-wise gated process of proton translocation is emphasized, where discrete electron transfer events are coupled to proton uptake and expulsion. The trajectory of each pumped proton is the same for all four substrate electrons. An essential role for the His-Tyr cross-linked species is discussed, in gating of the D- and K-channels and as an acceptor/donor of electrons and protons at the binuclear center.
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Affiliation(s)
- Martyn A Sharpe
- Department of Neurosurgery, The Methodist Hospital, Houston, TX 77030, USA.
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Qin L, Sharpe MA, Garavito RM, Ferguson-Miller S. Conserved lipid-binding sites in membrane proteins: a focus on cytochrome c oxidase. Curr Opin Struct Biol 2007; 17:444-50. [PMID: 17719219 PMCID: PMC2395296 DOI: 10.1016/j.sbi.2007.07.001] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2007] [Revised: 07/06/2007] [Accepted: 07/09/2007] [Indexed: 11/24/2022]
Abstract
Specific interactions between lipids and membrane proteins have been observed in recent high-resolution crystal structures of membrane proteins. A number of cytochrome oxidase structures were analyzed, along with many amino acid sequences of membrane-spanning regions aligned according to their location in the membrane. The results reveal conservation of lipid-binding sites and of the residues that form them. These studies imply that bound lipids have important roles that are crucial to the assembly, structure, or activity of the protein. Evidence for some of these roles in subunit interactions, membrane insertion, and protein-protein complex formation is reviewed.
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Affiliation(s)
- Ling Qin
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824-1319, USA
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Samai M, Sharpe MA, Gard PR, Chatterjee PK. Comparison of the effects of the superoxide dismutase mimetics EUK-134 and tempol on paraquat-induced nephrotoxicity. Free Radic Biol Med 2007; 43:528-34. [PMID: 17640563 DOI: 10.1016/j.freeradbiomed.2007.05.014] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/19/2007] [Accepted: 05/04/2007] [Indexed: 11/20/2022]
Abstract
Paraquat-induced nephrotoxicity involves severe renal cell damage caused by reactive oxygen species (ROS), specifically via increasing concentrations of superoxide anions in the kidney. Recently, superoxide dismutase (SOD) mimetics (SODm) have been developed that display safe SOD activities but which also possess additional antioxidant enzyme (e.g., catalase) or ROS-scavenging activities. The aim of this study was to compare the effects of two such SODm, specifically, EUK-134, a SODm with catalase activity, and tempol, a SODm with ROS-scavenging properties, on paraquat-induced nephrotoxicity of renal NRK-52E cells. Incubation with paraquat (1 mM) for 24 h reduced cell viability and increased necrosis significantly. Paraquat also generated significant quantities of superoxide anions and hydroxyl radicals. Both EUK-134 (10-300 microM) and tempol (0.3-1.0 mM) were able to improve cell viability and reduced paraquat-induced cell death significantly via dismutation or scavenging of superoxide anions and reduced hydroxyl radical generation. The data presented here suggest that SODm such as EUK-134 and tempol, which possess additional catalase and/or ROS-scavenging activities, can significantly reduce renal cell damage caused by paraquat. These effects were evident at concentrations which avoid the pro-oxidant activities associated with higher concentrations of SOD. Such SODm could therefore prove to be beneficial as therapies for paraquat nephrotoxicity.
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Affiliation(s)
- Mohamed Samai
- Department of Pharmacology and Therapeutics, University of Brighton, Brighton BN2 4GJ, East Sussex, UK
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Xu J, Sharpe MA, Qin L, Ferguson-Miller S, Voth GA. Storage of an excess proton in the hydrogen-bonded network of the d-pathway of cytochrome C oxidase: identification of a protonated water cluster. J Am Chem Soc 2007; 129:2910-3. [PMID: 17309257 PMCID: PMC2556150 DOI: 10.1021/ja067360s] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The mechanism of proton transport in the D-pathway of cytochrome c oxidase (CcO) is further elucidated through examining a protonated water/hydroxyl cluster inside the channel. The second generation multi-state empirical valence bond (MS-EVB2) model was employed in a molecular dynamics study based on a high-resolution X-ray structure to simulate the interaction of the excess proton with the channel environment. Our results indicate that a hydrogen-bonded network consisting of about 5 water molecules surrounded by three side chains and two backbone groups (S197, S200, S201, F108) is involved in storage and translocation of an excess proton to the extracellular side of CcO.
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Affiliation(s)
- Jiancong Xu
- Department of Chemistry and Center for Biophysical Modeling and Simulation, 315 South 1400 East Room 2020, University of Utah, Salt Lake City, UT 84112-0850, USA
| | - Martyn A. Sharpe
- Department of Biochemistry & Molecular Biology, Michigan State University, East Lansing, Michigan 48824-1319, USA
| | - Ling Qin
- Department of Biochemistry & Molecular Biology, Michigan State University, East Lansing, Michigan 48824-1319, USA
| | - Shelagh Ferguson-Miller
- Department of Biochemistry & Molecular Biology, Michigan State University, East Lansing, Michigan 48824-1319, USA
| | - Gregory A. Voth
- Department of Chemistry and Center for Biophysical Modeling and Simulation, 315 South 1400 East Room 2020, University of Utah, Salt Lake City, UT 84112-0850, USA
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Rejdak K, Petzold A, Sharpe MA, Kay AD, Kerr M, Keir G, Thompson EJ, Giovannoni G. Cerebrospinal fluid nitrite/nitrate correlated with oxyhemoglobin and outcome in patients with subarachnoid hemorrhage. J Neurol Sci 2004; 219:71-6. [PMID: 15050440 DOI: 10.1016/j.jns.2003.12.011] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2003] [Revised: 11/06/2003] [Accepted: 12/16/2003] [Indexed: 10/26/2022]
Abstract
The findings of various studies reporting temporal changes in CSF total nitrite/nitrate (NOx) levels after subarachnoid hemorrhage (SAH) vary considerably. The study group comprised 10 patients with SAH and 10 control subjects. Total nitrite/nitrate concentration was measured by a vanadium-based assay with the colorimetric Griess reaction. CSF oxyhemoglobin level was assessed by spectrophotometry. After an initial peak (22.6+/-10.1 microM) within first 24 h after SAH, CSF NOx decreased gradually during the period of observation. There was a significant correlation between CSF concentrations of NOx and OxyHb in the entire observation period (R=0.87, p<0.001). When the impact of bleeding into CSF was considered, patients with very good outcome [Glasgow Outcome Scale (GOS)=5] had significantly lower CSF NOx (11.1+/-1.3 microM) than those with worse outcome (GOS<5) (21.8+/-11.2 microM, p<0.01). In conclusion, this study demonstrates that after aneurysm rupture CSF NOx levels correlate with OxyHb. We suggest this as a novel interpretation of other variable findings in relation to NO metabolites in the central nervous system (CNS) post SAH, and hence it could usefully be incorporated into the planning of future studies, correlating NOx with clinical outcome.
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Affiliation(s)
- Konrad Rejdak
- Department Neuroinflammation, Institute of Neurology, Queen Square, London WC1N 3BG, UK
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Chatterjee PK, Patel NSA, Kvale EO, Brown PAJ, Stewart KN, Mota-Filipe H, Sharpe MA, Di Paola R, Cuzzocrea S, Thiemermann C. EUK-134 reduces renal dysfunction and injury caused by oxidative and nitrosative stress of the kidney. Am J Nephrol 2004; 24:165-77. [PMID: 14752229 DOI: 10.1159/000076547] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2003] [Accepted: 12/09/2003] [Indexed: 01/08/2023]
Abstract
BACKGROUND/AIMS Oxidative and nitrosative stress plays important roles in the pathogenesis of renal ischemia/reperfusion (I/R) injury. Here we investigate the effect of EUK-134, a synthetic superoxide dismutase and catalase mimetic, (i) on renal dysfunction and injury caused by I/R in vivo and (ii) on proximal tubular cell (PTC) injury and death caused by oxidative and nitrosative stress. METHODS Rats, subjected to bilateral renal ischemia (45 min) followed by reperfusion (6 h), were administered EUK-134 (0.3 and 3 mg/kg, i.v.) prior to and during reperfusion, after which biochemical and histological indicators of renal dysfunction and injury were measured. The expression of poly(ADP-ribose) (PAR) and inducible nitric oxide (NO) synthase (iNOS) and nitrotyrosine formation were determined immunohistochemically and used as indicators of oxidative and nitrosative stress. Primary cultures of rat PTCs, isolated and cultured from the kidney cortex, were incubated with hydrogen peroxide (H2O2; 1 mM for 2 h) in the presence of increasing concentrations of EUK-134 (1-100 microM) after which PTC injury and death were measured. The effects of EUK-134 on serum levels of NO in rats subjected to renal I/R or on NO production by PTCs incubated with interferon-gamma (IFN-gamma, 100 IU/ml) and bacterial lipopolysaccharide (LPS, 10 microg/ml) in combination for 24 h were also measured. RESULTS EUK-134 produced a significant reduction in renal dysfunction and injury caused by I/R. Specifically, serum creatinine levels, an indicator of renal dysfunction, were reduced from 227 +/- 11 (n = 12, I/R only) to 146 +/- 9 microM (n = 12, I/R +3 mg/kg EUK-134). Urinary N-acetyl-beta-D-glucosaminidase activity, an indicator of tubular damage, was reduced from 42 +/- 5 (n = 12, I/R only) to 22 +/- 3 IU/l (n = 12, I/R +3 mg/kg EUK-134). EUK-134 significantly reduced renal injury caused by oxidative stress in vivo (reduction in PAR formation), and in vitro EUK-134 reduced PTC injury and death caused by H2O2. However, EUK-134 also reduced nitrosative stress caused by I/R in vivo (reduction of iNOS expression and nitrotyrosine formation), which was reflected by a significant reduction in serum NO levels in rats subjected to renal I/R. Specifically, serum NO levels were reduced from 57 +/- 12 (n = 12, I/R only) to 23 +/- 3 mM (n = 12, I/R +3 mg/kg EUK-134). In vitro, EUK-134 significantly reduced NO production by PTCs incubated with IFN-gamma/LPS. CONCLUSION We propose that EUK-134 reduces renal I/R injury not only via reduction of oxidative stress, but also by reducing nitrosative stress caused by renal I/R.
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Affiliation(s)
- Prabal K Chatterjee
- Department of Experimental Medicine, Nephrology and Critical Care, William Harvey Research Institute, Queen Mary University of London, London, UK
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Cooper CE, Davies NA, Psychoulis M, Canevari L, Bates TE, Dobbie MS, Casley CS, Sharpe MA. Nitric oxide and peroxynitrite cause irreversible increases in the Km for oxygen of mitochondrial cytochrome oxidase: in vitro and in vivo studies. Biochimica et Biophysica Acta (BBA) - Bioenergetics 2003; 1607:27-34. [PMID: 14556910 DOI: 10.1016/j.bbabio.2003.08.003] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Mitochondrial cytochrome oxidase is competitively and reversibly inhibited by inhibitors that bind to ferrous heme, such as carbon monoxide and nitric oxide. In the case of nitric oxide, nanomolar levels inhibit cytochrome oxidase by competing with oxygen at the enzyme's heme-copper active site. This raises the K(m) for cellular respiration into the physiological range. This effect is readily reversible and may be a physiological control mechanism. Here we show that a number of in vitro and in vivo conditions result in an irreversible increase in the oxygen K(m). These include: treatment of the purified enzyme with peroxynitrite or high (microM) levels of nitric oxide; treatment of the endothelial-derived cell line, b.End5, with NO; activation of astrocytes by cytokines; reperfusion injury in the gerbil brain. Studies of cell respiration that fail to vary the oxygen concentration systematically are therefore likely to significantly underestimate the degree of irreversible damage to cytochrome oxidase.
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Affiliation(s)
- Chris E Cooper
- Department of Biological Sciences, University of Essex, Central Campus Wivenhoe Park, Essex CO4 3SQ, Colchester, UK.
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Abstract
We have examined the action of nitric oxide (NO) on the ability of Fenton's reagent (ferrous iron and hydrogen peroxide), to oxidize a number of organic optical probes. We found that NO is able to arrest the oxidation of organic compounds at concentrations of NO found in brain, in vivo. We present evidence that Fenton's reagent proceeds via a ferryl intermediate ([Fe[double bond]O]2+), before the generation of hydroxyl radical *OH. NO reacts rapidly with this ferryl, blocking the production of *OH. We propose that NO has an important role in protecting biological tissues, and the brain in particular, from Fenton chemistry.
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Affiliation(s)
- Martyn A Sharpe
- Miriam Marks Department of Neurochemistry, Institute of Neurology, University College London, UK.
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Rejdak K, Petzold A, Sharpe MA, Smith M, Keir G, Stelmasiak Z, Thompson EJ, Giovannoni G. Serum and urine nitrate and nitrite are not reliable indicators of intrathecal nitric oxide production in acute brain injury. J Neurol Sci 2003; 208:1-7. [PMID: 12639718 DOI: 10.1016/s0022-510x(02)00412-4] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [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: 01/02/2023]
Abstract
This study examined the correlation between nitric oxide (NO) metabolites in the three major body fluid compartments and assessed performance of newly described vanadium-based assay for simultaneous detection of nitrite and nitrate (NO(x)) in human samples. Vanadium reduces nitrate to nitrite, which can be measured after a colorimetric reaction with Griess reagents. Cisternal cerebro spinal fluid (CSF), serum and urine samples from 10 patients with acute brain injury (ABI) were compared to control subjects. Significantly higher CSF NO(x) levels were found in brain injury patients compared to control patients (19.7+/-13.7 vs. 6.5+/-2.3 microM; p=0.01), which persisted for 10-day period of observation. The serum and urine levels of NO(x) on admission were not statistically different (42.8+/-28.2 microM; 584.1+/-337.8 micromol/g Cr, respectively) from controls (36.8+/-14.8 microM; 819.7+/-356.0 micromol/g Cr), but tended to decrease during the disease course reaching the lowest level on day 6 (serum: 19.3+/-8.4 microM, urine: 300.4+/-111.9 micromol/g Cr). CSF levels of NO(x) correlated moderately with those in serum (p=0.001, R=0.5). Serum NO(x) concentrations correlated weakly with urine levels (p=0.04, R=0.3). There was no significant correlation between CSF NO(x) and urine NO(x) levels. In conclusion, patients suffering brain injury had increased NO(x) concentrations in CSF, which remained independent from other body fluid compartments. Serum and urinary NO(x) levels cannot be used as a reliable index to assess intrathecal NO production.
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Affiliation(s)
- K Rejdak
- Department of Neuroinflammation, Institute of Neurology, Queen Square, London WC1N 3BG, UK
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McDonald MC, d'Emmanuele di Villa Bianca R, Wayman NS, Pinto A, Sharpe MA, Cuzzocrea S, Chatterjee PK, Thiemermann C. A superoxide dismutase mimetic with catalase activity (EUK-8) reduces the organ injury in endotoxic shock. Eur J Pharmacol 2003; 466:181-9. [PMID: 12679155 DOI: 10.1016/s0014-2999(03)01538-3] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.5] [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: 11/19/2022]
Abstract
Reactive oxygen species contribute to the multiple organ failure in endotoxic shock. Here, we investigate the effects of a salen-manganese complex, which exhibits both superoxide dismutase and catalase activity (EUK-8), on the circulatory failure, renal and liver injury and dysfunction caused by endotoxin in the anaesthetised rat. Endotoxaemia (6 mg/kg i.v., Escherichia coli lipopolysaccharide) for 6 h caused hypotension, renal dysfunction and liver injury. Treatment of rats with EUK-8 (0.3 or 1 mg/kg bolus injection followed by an infusion of 0.3 or 1 mg/kg/h) attenuated the renal and liver injury and dysfunction in a dose-related fashion. In addition, the higher dose of EUK-8 attenuated the delayed hypotension caused by endotoxin in the rat. Thus, an enhanced formation of reactive oxygen species importantly contributes to the circulatory failure, as well as the organ injury and dysfunction associated with endotoxic shock. We propose that small molecules, which have the catalytic activity of both superoxide dismutase and catalase, may represent a novel therapeutic approach for the therapy of endotoxic shock.
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Affiliation(s)
- Michelle C McDonald
- The William Harvey Research Institute, St. Bartholomew's and The Royal London School of Medicine and Dentistry, Charterhouse Square, EC1M 6BQ, London, UK
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Stewart VC, Stone R, Gegg ME, Sharpe MA, Hurst RD, Clark JB, Heales SJR. Preservation of extracellular glutathione by an astrocyte derived factor with properties comparable to extracellular superoxide dismutase. J Neurochem 2002; 83:984-91. [PMID: 12421371 DOI: 10.1046/j.1471-4159.2002.01216.x] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.9] [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: 01/30/2023]
Abstract
Cultured rat and human astrocytes and rat neurones were shown to release reduced glutathione (GSH). In addition, GSH oxidation was retarded by the concomitant release of a factor from the cells. One possibility is that this factor is extracellular superoxide dismutase (SOD). In support of this, the factor was found to bind heparin, have a molecular mass estimated to be between 50 and 100 kDa, and CuZn-type SOD protein and cyanide sensitive enzyme activity were demonstrated in the cell-conditioned medium. In addition, supplementation of native medium with exogenous CuZn-type SOD suppressed GSH oxidation. We propose that preservation of released GSH is essential to allow for maximal up-regulation of GSH metabolism in neurones. Furthermore, cytokine stimulation of astrocytes increased release of the extracellular SOD, and enhanced stability of GSH. This may be a protective strategy occurring in vivo under conditions of oxidative stress, and suggests that SOD mimetics may be of therapeutic use.
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Affiliation(s)
- Victoria C Stewart
- Department of Molecular Pathogenesis, Division of Neurochemistry, UCL, Institute of Neurology, London, UK
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Abstract
Reactive oxygen species (ROS) contribute to the multiple organ failure (MOF) in hemorrhagic shock. Here we investigate the effects of two superoxide dismutase (SOD) mimetics with catalase activity (EUK-8 and EUK-134) on the circulatory failure and the organ injury and dysfunction associated with hemorrhagic shock in the anesthetised rat. Hemorrhage (sufficient to lower mean arterial blood pressure to 45 mmHg for 90 min) and subsequent resuscitation with shed blood resulted (within 4 h after resuscitation) in a delayed fall in blood pressure, liver injury and renal dysfunction as well as pancreatic injury. Treatment of rats on resuscitation with EUK-8 (3 mg/kg i.v. bolus followed by 3 mg/kg/h i.v. infusion) significantly attenuated liver injury, renal dysfunction and pancreatic injury caused by hemorrhage and resuscitation. Administration of EUK-134 (3 mg/kg i.v. bolus followed by 3 mg/kg/h) reduced the liver injury and renal dysfunction (but not the pancreatic injury) caused by hemorrhagic shock. However, neither EUK-8 nor EUK-134 reduced the delayed circulatory failure associated with hemorrhagic shock. Thus, we propose that an enhanced formation of ROS contributes to the MOF in hemorrhagic shock, and that membrane-permeable SOD-mimetics with catalase activity, such as EUK-8 or EUK-134, may represent a novel therapeutic approach for the therapy of hemorrhagic shock.
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Affiliation(s)
- Maya Izumi
- Department of Experimental Medicine & Nephrology, The William Harvey Research Institute, St. Bartholomew's and the Royal London School of Medicine & Dentistry, Queen Mary, University of London, United Kingdom
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Sharpe MA, Ollosson R, Stewart VC, Clark JB. Oxidation of nitric oxide by oxomanganese-salen complexes: a new mechanism for cellular protection by superoxide dismutase/catalase mimetics. Biochem J 2002; 366:97-107. [PMID: 11994046 PMCID: PMC1222749 DOI: 10.1042/bj20020154] [Citation(s) in RCA: 122] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2002] [Revised: 04/04/2002] [Accepted: 05/07/2002] [Indexed: 11/17/2022]
Abstract
Manganese-salen complexes (Mn-Salen), including EUK-8 [manganese N,N'-bis(salicylidene)ethylenediamine chloride] and EUK-134 [manganese 3-methoxy N,N'-bis(salicylidene)ethylenediamine chloride], have been reported to possess combined superoxide dismutase (SOD) and catalase mimetic functions. Because of this SOD/catalase mimicry, EUK-8 and EUK-134 have been investigated as possible therapeutic agents in neurological disorders resulting from oxidative stress, including Alzheimer's disease, Parkinson's disease, stroke and multiple sclerosis. These actions have been explained by the ability of the Mn-Salen to remove deleterious superoxide (O(2)(-)) and H(2)O(2). However, in addition to oxidative stress, cells in models for neurodegenerative diseases may also be subjected to damage from reactive nitrogen oxides (nitrosative stress), resulting from elevated levels of NO and sister compounds, including peroxynitrite (ONOO(-)). We have been examining the interaction of EUK-8 and EUK-134 with NO and ONOO(-). We find that in the presence of a per-species (H(2)O(2), ONOO(-), peracetate and persulphate), the Mn-Salen complexes are oxidized to the corresponding oxo-species (oxoMn-Salen). OxoMn-Salens are potent oxidants, and we demonstrate that they can rapidly oxidize NO to NO(2) and also oxidize nitrite (NO(2)(-) to nitrate (NO(2)(-)). Thus these Mn-Salens have the potential to ameliorate cellular damage caused by both oxidative and nitrosative stresses, by the catalytic breakdown of O(2)(-), H(2)O(2), ONOO(-) and NO to benign species: O(2), H(2)O, NO(2)(-) and NO(3)(-).
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Affiliation(s)
- Martyn A Sharpe
- Department of Molecular Pathogenesis, Division of Neurochemistry, Institute of Neurology, University College London, Queen Square, London WC1N 3BG, U.K.
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Reeder BJ, Sharpe MA, Kay AD, Kerr M, Moore K, Wilson MT. Toxicity of myoglobin and haemoglobin: oxidative stress in patients with rhabdomyolysis and subarachnoid haemorrhage. Biochem Soc Trans 2002; 30:745-8. [PMID: 12196184 DOI: 10.1042/bst0300745] [Citation(s) in RCA: 80] [Impact Index Per Article: 3.6] [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: 11/17/2022]
Abstract
Haemolytic events, such as those following rhabdomyolysis and subarachnoid haemorrhage, often result in pathological complications such as vasoconstriction. Haem-protein cross-linked myoglobin and haemoglobin are generated by ferric-ferryl redox cycling, and thus can be used as markers of oxidative stress. We have found haem-protein cross-linked myoglobin in the urine of patients suffering from rhabdomyolysis and haem-protein cross-linked haemoglobin in the cerebrospinal fluid of patients following subarachnoid haemorrhage. These findings provide strong evidence that these respiratory haem proteins can be involved in powerful oxidation processes in vivo. We have previously proposed that these oxidation processes in rhabdomyolysis include the formation of potent vasoconstrictor molecules, generated by the myoglobin-catalysed oxidation of membranes, inducing nephrotoxicity and renal failure. Haem-protein cross-linked haemoglobin in cerebrospinal fluid suggests that a similar mechanism of lipid oxidation is present and that this may provide a mechanistic basis for the delayed vasospasm that follows subarachnoid haemorrhage.
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Affiliation(s)
- B J Reeder
- Department of Biological Sciences, University of Essex, Wivenhoe Park, Colchester CO4 3SQ, UK.
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Casley CS, Land JM, Sharpe MA, Clark JB, Duchen MR, Canevari L. β-Amyloid Fragment 25–35 Causes Mitochondrial Dysfunction in Primary Cortical Neurons. Neurobiol Dis 2002; 10:258-67. [PMID: 12270688 DOI: 10.1006/nbdi.2002.0516] [Citation(s) in RCA: 164] [Impact Index Per Article: 7.5] [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: 11/22/2022] Open
Abstract
Beta-amyloid deposition and compromised energy metabolism both occur in vulnerable brain regions in Alzheimer's disease. It is not known whether beta-amyloid is the cause of impairment of energy metabolism, nor whether impaired energy metabolism is specific to neurons. Our results, using primary neuronal cultures, show that 24-h incubation with A beta(25-35) caused a generalized decrease in the specific activity of mitochondrial enzymes per milligram of cellular protein, induced mitochondrial swelling, and decreased total mitochondrial number. Incubation with A beta(25-35) decreased ATP concentration to 58% of control in neurons and 71% of control in astrocytes. Levels of reduced glutathione were also lowered by A beta(25-35) in both neurons (from 5.1 to 2.9 nmol/mg protein) and astrocytes (from 25.2 to 14.9 nmol/mg protein). We conclude that 24-h treatment with extracellular A beta(25-35) causes mitochondrial dysfunction in both astrocytes and neurons, the latter being more seriously affected. In astrocytes mitochondrial impairment was confined to complex I inhibition, whereas in neurons a generalized loss of mitochondria was seen.
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Affiliation(s)
- C S Casley
- Division of Neurochemistry, Institute of Neurology, University College London, Queen Square, London WC1N 3BG, United Kingdom
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Reeder BJ, Svistunenko DA, Sharpe MA, Wilson MT. Characteristics and mechanism of formation of peroxide-induced heme to protein cross-linking in myoglobin. Biochemistry 2002; 41:367-75. [PMID: 11772036 DOI: 10.1021/bi011335b] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.0] [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: 11/29/2022]
Abstract
At acidic pH values heme-protein cross-linked myoglobin (Mb-H) forms as a product of a peroxide-induced ferric-ferryl redox cycle. There is evidence that this molecule acts as a marker for heme-protein-induced oxidative stress in vivo and may exacerbate the severity of oxidative damage due to its enhanced prooxidant and pseudoperoxidatic activities. Therefore, an understanding of its properties and mechanism of formation may be important in understanding the association between heme-proteins and oxidative stress. Although the mechanism of formation of heme-protein cross-linked myoglobin is thought to involve a protein radical (possibly a tyrosine) and the ferryl heme, we show that this hypothesis needs revising. We provide evidence that in addition to a protein-based radical the protonated form of the oxoferryl heme, known to be highly reactive and radical-like in nature, is required to initiate cross-linking. This revised mechanism involves radical/radical termination rather than attack of a single radical onto the porphyrin ring. This proposal better explains the pH dependence of cross-linking and may, in part, explain the therapeutic effectiveness of increasing the pH on myoglobin-induced oxidative stress, e.g., therapy for rhabdomyolysis-associated renal dysfunction.
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Affiliation(s)
- Brandon J Reeder
- Department of Biological Sciences, Central Campus, University of Essex, Wivenhoe Park, Colchester, Essex CO4 3SQ, United Kingdom.
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Abstract
Disrupted energy metabolism, in particular reduced activity of cytochrome oxidase (EC 1.9.3.1), alpha-ketoglutarate dehydrogenase (EC 1.2.4.2) and pyruvate dehydrogenase (EC 1.2.4.1) have been reported in post-mortem Alzheimer's disease brain. beta-Amyloid is strongly implicated in Alzheimer's pathology and can be formed intracellularly in neurones. We have investigated the possibility that beta-amyloid itself disrupts mitochondrial function. Isolated rat brain mitochondria have been incubated with the beta-amyloid alone or together with nitric oxide, which is known to be elevated in Alzheimer's brain. Mitochondrial respiration, electron transport chain complex activities, alpha-ketoglutarate dehydrogenase activity and pyruvate dehydrogenase activity have been measured. Beta-amyloid caused a significant reduction in state 3 and state 4 mitochondrial respiration that was further diminished by the addition of nitric oxide. Cytochrome oxidase, alpha-ketoglutarate dehydrogenase and pyruvate dehydrogenase activities were inhibited by beta-amyloid. The K(m) of cytochrome oxidase for reduced cytochrome c was raised by beta-amyloid. We conclude that beta-amyloid can directly disrupt mitochondrial function, inhibits key enzymes and may contribute to the deficiency of energy metabolism seen in Alzheimer's disease.
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Affiliation(s)
- C S Casley
- Department of Neurochemistry, Institute of Neurology, London, UK
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41
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Svistunenko DA, Sharpe MA, Nicholls P, Blenkinsop C, Davies NA, Dunne J, Wilson MT, Cooper CE. The pH dependence of naturally occurring low-spin forms of methaemoglobin and metmyoglobin: an EPR study. Biochem J 2000; 351 Pt 3:595-605. [PMID: 11042113 PMCID: PMC1221398] [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: 02/18/2023]
Abstract
The paramagnetic species in human metHb and horse metmyoglobin (metMb) have been studied at low temperature using EPR spectroscopy. The high-spin (HS) haem signal in aquometMb has a greater rhombic distortion than the HS metHb signal. Nevertheless, the individual line width (g=6) is smaller in metMb than in metHb, consistent with non-identical signals from the alpha and beta Hb subunits. Three low-spin (LS) haem forms are present in metHb, while metMb has only two. The major LS form in both proteins is the alkaline species (with OH(-) at the sixth co-ordination position). The minor LS forms are assigned to different histidine hemichromes in equilibrium with the normal HS species at low temperature. LS forms disappear when the haem is bound by a ligand, such as fluoride, which ensures 100% occupancy of the HS state both at room temperature and at 25 K. The small differences in effective g-factors of the histidine hemichromes are interpreted in terms of different distances between the distal histidine and haem iron. The pH dependence of the inter-conversion of the different paramagnetic species is consistent with a model whereby protonation of a residue with a pK of 5.69 (metHb) or 6.12 (metMb), affects ligand binding and transformation from the HS to the LS form. Chemical and spectroscopic considerations suggest that the residue is unlikely to be the proximal or distal histidine. We therefore propose a model where protonation of this distant amino acid causes a conformational change at the iron site. Identical effects are seen in frozen human blood, suggesting that this effect may have physiological significance.
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Affiliation(s)
- D A Svistunenko
- Department of Biological Sciences, Central Campus, University of Essex, Wivenhoe Park, Colchester, Essex CO4 3SQ, UK
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Stewart VC, Sharpe MA, Clark JB, Heales SJ. Astrocyte-derived nitric oxide causes both reversible and irreversible damage to the neuronal mitochondrial respiratory chain. J Neurochem 2000; 75:694-700. [PMID: 10899944 DOI: 10.1046/j.1471-4159.2000.0750694.x] [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] [Indexed: 11/20/2022]
Abstract
Cytokine-stimulated astrocytes produce nitric oxide (NO), which, along with its metabolite peroxynitrite (ONOO(-)), can inhibit components of the mitochondrial respiratory chain. We used astrocytes as a source of NO/ONOO(-) and monitored the effects on neurons in coculture. We previously demonstrated that astrocytic NO/ONOO(-) causes significant damage to the activities of complexes II/III and IV of neighbouring neurons after a 24-h coculture. Under these conditions, no neuronal death was observed. Using polytetrafluoroethane filters, which are permeable to gases such as NO but impermeable to NO derivatives, we have now demonstrated that astrocyte-derived NO is responsible for the damage observed in our coculture system. Expanding on these observations, we have now shown that 24 h after removal of NO-producing astrocytes, neurons exhibit complete recovery of complex II/III and IV activities. Furthermore, extending the period of exposure of neurons to NO-producing astrocytes does not cause further damage to the neuronal mitochondrial respiratory chain. However, whereas the activity of complex II/III recovers with time, the damage to complex IV caused by a 48-h coculture with NO-producing astrocytes is irreversible. Therefore, it appears that neurons can recover from short-term damage to mitochondrial complex II/III and IV, whereas exposure to astrocytic-derived NO for longer periods causes permanent damage to neuronal complex IV.
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Affiliation(s)
- V C Stewart
- Department of Neurochemistry, Institute of Neurology, University College London, England.
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43
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Abstract
Previous studies have shown that the addition of nitric oxide to cytochrome c oxidase rapidly generates spectral changes compatible with the formation of nitrite at the binuclear haem:copper centre. Here we directly demonstrate nitrite release following nitric oxide addition to the enzyme. The nitrite complex is kinetically inactive and the off rate for nitrite was found to be slow (0.024 min(-1)). However, the presence of reductants enhances the off rate and enables cytochrome oxidase to catalyse the rapid oxidation of nitric oxide to nitrite free in solution. This may play a major role in the mitochondrial metabolism of nitric oxide.
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Affiliation(s)
- J Torres
- Department of Biological Sciences, University of Essex, Wivenhoe Park, Essex CO4 3SQ, Colchester, UK
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44
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Svistunenko DA, Sharpe MA, Nicholls P, Wilson MT, Cooper CE. A new method for quantitation of spin concentration by EPR spectroscopy: application to methemoglobin and metmyoglobin. J Magn Reson 2000; 142:266-275. [PMID: 10648142 DOI: 10.1006/jmre.1999.1935] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
A new method of EPR spectral analysis is developed to quantitate overlapping signals. The method requires double integration of a number of spectra containing the signals in different proportions and the subsequent solution of a system of linear equations. The result gives the double integral values of the individual lines, which can then be further used to find the concentrations of all the paramagnetic species present. There is no requirement to deconvolute the whole spectrum into its individual components. The method is employed to quantify different heme species in methemoglobin and metmyoglobin preparations. A significantly greater intensity of the high-spin signal in metmyoglobin, compared to methemoglobin at the same heme concentration, is shown to be due to larger amounts of low-spin forms in methemoglobin. Three low-spin types in methemoglobin and two in metmyoglobin are present in these samples. When their calculated concentrations are added to those of the high-spin forms, the results correspond to the total heme concentrations obtained by optical spectroscopy.
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Affiliation(s)
- D A Svistunenko
- Department of Biological Sciences, Central Campus, University of Essex, Wivenhoe Park, Essex, CO4 3SQ, United Kingdom
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Cooper CE, Torres J, Sharpe MA, Wilson MT, Svistunenko DA. Peroxynitrite reacts with methemoglobin to generate globin-bound free radical species. Implications for vascular injury. Adv Exp Med Biol 1999; 454:195-202. [PMID: 9889893 DOI: 10.1007/978-1-4615-4863-8_24] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Affiliation(s)
- C E Cooper
- Department of Biological and Chemical Sciences, University of Essex, Colchester, United Kingdom
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46
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Sharpe MA, Cooper CE. Interaction of peroxynitrite with mitochondrial cytochrome oxidase. Catalytic production of nitric oxide and irreversible inhibition of enzyme activity. J Biol Chem 1998; 273:30961-72. [PMID: 9812992 DOI: 10.1074/jbc.273.47.30961] [Citation(s) in RCA: 106] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Purified mitochondrial cytochrome c oxidase catalyzes the conversion of peroxynitrite to nitric oxide (NO). This reaction is cyanide-sensitive, indicating that the binuclear heme a3/CuB center is the catalytic site. NO production causes a reversible inhibition of turnover, characterized by formation of the cytochrome a3 nitrosyl complex. In addition, peroxynitrite causes irreversible inhibition of cytochrome oxidase, characterized by a decreased Vmax and a raised Km for oxygen. Under these conditions, the redox state of cytochrome a is elevated, indicating inhibition of electron transfer and/or oxygen reduction reactions subsequent to this center. The lipid bilayer is no barrier to these peroxynitrite effects, as NO production and irreversible enzyme inhibition were also observed in cytochrome oxidase proteoliposomes. Addition of 50 microM peroxynitrite to 10 microM fully oxidized enzyme induced spectral changes characteristic of the formation of ferryl cytochrome a3, partial reduction of cytochrome a, and irreversible damage to the CuA site. Higher concentrations of peroxynitrite (250 microM) cause heme degradation. In the fully reduced enzyme, peroxynitrite causes a red shift in the optical spectrum of both cytochromes a and a3, resulting in a symmetrical peak in the visible region. Therefore, peroxynitrite can both modify and degrade the metal centers of cytochrome oxidase.
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Affiliation(s)
- M A Sharpe
- Department of Biological Sciences, Central Campus, University of Essex, Wivenhoe Park, Colchester CO4 3SQ, United Kingdom
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47
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Sharpe MA, Cooper CE. Reactions of nitric oxide with mitochondrial cytochrome c: a novel mechanism for the formation of nitroxyl anion and peroxynitrite. Biochem J 1998; 332 ( Pt 1):9-19. [PMID: 9576846 PMCID: PMC1219446 DOI: 10.1042/bj3320009] [Citation(s) in RCA: 171] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The aerobic reactions of nitric oxide with cytochrome c were analysed. Nitric oxide (NO) reacts with ferrocytochrome c at a rate of 200 M-1 s-1 to form ferricytochrome c and nitroxyl anion (NO-). Ferricytochrome c was detected by optical spectroscopy; NO- was detected by trapping with metmyoglobin (Mb3+) to form the EPR-detectable Mb-nitrosyl complex, and by the formation of dimers in yeast ferrocytochrome c via cross-linking of the free cysteine residue. The NO- formed subsequently reacted with oxygen to form peroxynitrite, as measured by the oxidation of dihydrorhodamine 123. NO binds to ferricytochrome c to form the ferricytochrome c-NO complex. The on-rate for this reaction is 1.3+/-0.4x10(3) M-1.s-1, and the off-rate is 0.087+/-0.054 s-1. The dissociation constant (Kd) of the complex is 22+/-7 microM. These reactions of NO with cytochrome c are likely to be relevant to mitochondrial metabolism of NO. Ferricytochrome c can act as a reversible sink for excess NO in the mitochondria. The reduction of NO to NO- by ferrocytochrome c may play a role in the irreversible inhibition of mitochondrial oxygen consumption by peroxynitrite. It is generally assumed that peroxynitrite would be formed in mitochondria via the reaction of NO with superoxide. The finding that NO- is formed from the reaction of NO and ferrocytochrome c provides a means of producing peroxynitrite in the absence of superoxide, via the reaction of NO- with oxygen.
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Affiliation(s)
- M A Sharpe
- Department of Biological Sciences, Central Campus, University of Essex, Wivenhoe Park, Colchester CO4 3SQ, UK
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Cooper CE, Torres J, Sharpe MA, Wilson MT. Nitric oxide ejects electrons from the binuclear centre of cytochrome c oxidase by reacting with oxidised copper: a general mechanism for the interaction of copper proteins with nitric oxide? FEBS Lett 1997; 414:281-4. [PMID: 9315702 DOI: 10.1016/s0014-5793(97)01009-0] [Citation(s) in RCA: 90] [Impact Index Per Article: 3.3] [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: 02/05/2023]
Abstract
Small increases in NO concentration can inhibit mitochondrial oxygen consumption by reacting at the binuclear haem a3/CuB oxygen reduction site of cytochrome c oxidase. Here we demonstrate that under normal turnover conditions NO reacts initially with the oxidised CuB rather than the haem a3. We propose that hydration of an initial Cu+/NO+ complex forms nitrite, a proton and CuB+; the latter ejects an electron from the binuclear centre and results in the observed (100 s(-1)) reduction of other electron transfer centres in the enzyme (haem a and CuA). These reactions may have implications for the interactions of NO with other copper proteins.
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Affiliation(s)
- C E Cooper
- Department of Biological Sciences, University of Essex, Central Campus, Colchester, UK.
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Wilson MT, Torres J, Cooper CE, Sharpe MA. Interactions of cytochrome c oxidase with nitric oxide: reactions of the 'turnover' intermediates. Biochem Soc Trans 1997; 25:905-9. [PMID: 9388570 DOI: 10.1042/bst0250905] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- M T Wilson
- Department of Biological and Chemical Sciences, University of Essex, U.K
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50
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Affiliation(s)
- M A Sharpe
- Department of Biological and Chemical Sciences, University of Essex, Colchester, UK
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