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Manhas N, Duong QV, Lee P, Richardson JD, Robertson JD, Moxley MA, Bazil JN. Computationally modeling mammalian succinate dehydrogenase kinetics identifies the origins and primary determinants of ROS production. J Biol Chem 2020; 295:15262-15279. [PMID: 32859750 DOI: 10.1074/jbc.ra120.014483] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [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: 05/20/2020] [Revised: 08/25/2020] [Indexed: 01/01/2023] Open
Abstract
Succinate dehydrogenase (SDH) is an inner mitochondrial membrane protein complex that links the Krebs cycle to the electron transport system. It can produce significant amounts of superoxide ([Formula: see text]) and hydrogen peroxide (H2O2); however, the precise mechanisms are unknown. This fact hinders the development of next-generation antioxidant therapies targeting mitochondria. To help address this problem, we developed a computational model to analyze and identify the kinetic mechanism of [Formula: see text] and H2O2 production by SDH. Our model includes the major redox centers in the complex, namely FAD, three iron-sulfur clusters, and a transiently bound semiquinone. Oxidation state transitions involve a one- or two-electron redox reaction, each being thermodynamically constrained. Model parameters were simultaneously fit to many data sets using a variety of succinate oxidation and free radical production data. In the absence of respiratory chain inhibitors, model analysis revealed the 3Fe-4S iron-sulfur cluster as the primary [Formula: see text] source. However, when the quinone reductase site is inhibited or the quinone pool is highly reduced, [Formula: see text] is generated primarily by the FAD. In addition, H2O2 production is only significant when the enzyme is fully reduced, and fumarate is absent. Our simulations also reveal that the redox state of the quinone pool is the primary determinant of free radical production by SDH. In this study, we showed the importance of analyzing enzyme kinetics and associated side reactions in a consistent, quantitative, and biophysically detailed manner using a diverse set of experimental data to interpret and explain experimental observations from a unified perspective.
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Affiliation(s)
- Neeraj Manhas
- Department of Physiology, Michigan State University, East Lansing, Michigan, USA
| | - Quynh V Duong
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan, USA
| | - Pilhwa Lee
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan, USA
| | - Joshua D Richardson
- Department of Physiology, Michigan State University, East Lansing, Michigan, USA
| | - John D Robertson
- Department of Physiology, Michigan State University, East Lansing, Michigan, USA
| | - Michael A Moxley
- Department of Chemistry, University of Nebraska, Kearney, Nebraska, USA
| | - Jason N Bazil
- Department of Physiology, Michigan State University, East Lansing, Michigan, USA.
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Chen S, Cui J, Jiang T, Olson ES, Cai QY, Yang M, Wu W, Guthrie JM, Robertson JD, Lipton SA, Ma L, Tsien RY, Gu Z. Gelatinase activity imaged by activatable cell-penetrating peptides in cell-based and in vivo models of stroke. J Cereb Blood Flow Metab 2017; 37:188-200. [PMID: 26681768 PMCID: PMC5363737 DOI: 10.1177/0271678x15621573] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/05/2015] [Revised: 10/09/2015] [Accepted: 11/04/2015] [Indexed: 12/27/2022]
Abstract
Matrix metalloproteinases (MMPs), particularly gelatinases (MMP-2/-9), are involved in neurovascular impairment after stroke. Detection of gelatinase activity in vivo can provide insight into blood-brain barrier disruption, hemorrhage, and nerve cell injury or death. We applied gelatinase-activatable cell-penetrating peptides (ACPP) with a cleavable l-amino acid linker to examine gelatinase activity in primary neurons in culture and ischemic mouse brain in vivo We found uptake of Cy5-conjugated ACPP (ACPP-Cy5) due to gelatinase activation both in cultured neurons exposed to n-methyl-d-aspartate and in mice after cerebral ischemia. Fluorescence intensity was significantly reduced when cells or mice were treated with MMP inhibitors or when a cleavage-resistant ACPP-Cy5 was substituted. We also applied an ACPP dendrimer (ACPPD) conjugated with multiple Cy5 and/or gadolinium moieties for fluorescence and magnetic resonance imaging (MRI) in intact animals. Fluorescence analysis showed that ACPPD was detected in sub-femtomole range in ischemic tissues. Moreover, MRI and inductively coupled plasma mass spectrometry revealed that ACPPD produced quantitative measures of gelatinase activity in the ischemic region. The resulting spatial pattern of gelatinase activity and neurodegeneration were very similar. We conclude that ACPPs are capable of tracing spatiotemporal gelatinase activity in vivo, and will therefore be useful in elucidating mechanisms of gelatinase-mediated neurodegeneration after stroke.
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Affiliation(s)
- Shanyan Chen
- Department of Pathology and Anatomical Sciences, University of Missouri at Columbia, USA.,Center for Translational Neuroscience, University of Missouri at Columbia, USA
| | - Jiankun Cui
- Department of Pathology and Anatomical Sciences, University of Missouri at Columbia, USA.,Center for Translational Neuroscience, University of Missouri at Columbia, USA.,Truman VA Hospital Research Service
| | - Tao Jiang
- Department of Pharmacology, University of California San Diego School of Medicine, USA
| | - Emilia S Olson
- Department of Pharmacology, University of California San Diego School of Medicine, USA
| | - Quan-Yu Cai
- Truman VA Hospital Research Service.,Department of Radiology, University of Missouri at Columbia, USA
| | - Ming Yang
- Truman VA Hospital Research Service.,Department of Radiology, University of Missouri at Columbia, USA
| | - Wei Wu
- Department of Pathology and Anatomical Sciences, University of Missouri at Columbia, USA.,Center for Translational Neuroscience, University of Missouri at Columbia, USA
| | - James M Guthrie
- Research Reactor Center, University of Missouri at Columbia, USA
| | - J D Robertson
- Research Reactor Center, University of Missouri at Columbia, USA
| | - Stuart A Lipton
- Department of Neurosciences, University of California San Diego School of Medicine, USA.,Scintillon Institute Neurodegenerative Disease Center, USA
| | - Lixin Ma
- Truman VA Hospital Research Service.,Department of Radiology, University of Missouri at Columbia, USA
| | - Roger Y Tsien
- Department of Pharmacology, University of California San Diego School of Medicine, USA.,Howard Hughes Medical Institute, University of California San Diego School of Medicine, USA
| | - Zezong Gu
- Department of Pathology and Anatomical Sciences, University of Missouri at Columbia, USA .,Center for Translational Neuroscience, University of Missouri at Columbia, USA.,Truman VA Hospital Research Service
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Mason JA, Robertson JD, McCosker J, Williams BA, Brown SA. Assessment and validation of a defined fluid restriction protocol in the use of subcutaneous desmopressin for children with inherited bleeding disorders. Haemophilia 2016; 22:700-5. [PMID: 27385253 DOI: 10.1111/hae.12949] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/28/2016] [Indexed: 11/28/2022]
Abstract
INTRODUCTION Despite the availability of subcutaneous desmopressin (1-deamino-8-d-arginine vasopressin, SC-DDAVP) as a haemostatic agent for children with mild bleeding disorders, few publications specifically address the safety or efficacy of this mode of administration. AIM Our aim was to assess whether a defined fluid restriction protocol was effective in preventing hyponatremia in children receiving perioperative SC-DDAVP, and to document adequate biological and clinical response in this setting. METHODS We retrospectively analysed a cohort of children with mild bleeding disorders prescribed SC-DDAVP over a 5-year period following institution of a 'two-thirds maintenance' fluid restriction protocol. RESULTS Sixty-nine patients received SC-DDAVP following this protocol, including 15 with mild haemophilia A, 49 with von Willebrand disease (VWD) and five with platelet storage pool disorder. In patients who underwent formal preoperative assessment a complete or partial response was observed in 28/29 with type 1 VWD and 14/15 with mild haemophilia A. Perioperative SC-DDAVP provided excellent haemostasis in all patients, with no requirement for factor concentrate or blood products. Mild asymptomatic hyponatremia was detected in seven children who received multiple doses of DDAVP (lowest sodium 129 mmol L(-1) ); however, adherence to the prescribed fluid restriction protocol was questionable in six of these cases. Symptomatic hyponatremia was not observed. CONCLUSION Subcutaneous desmopressin was well-tolerated, with no serious side-effects observed, and good biological responses in preoperative trials. A two-thirds maintenance fluid regimen was effective at preventing symptomatic hyponatremia in our cohort, and is now the standard protocol for fluid restriction post-DDAVP administration in our centre.
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Affiliation(s)
- J A Mason
- Department of Haematology, Lady Cilento Children's Hospital, Brisbane, QLD, Australia.
| | - J D Robertson
- Department of Haematology, Lady Cilento Children's Hospital, Brisbane, QLD, Australia
| | - J McCosker
- Department of Haematology, Lady Cilento Children's Hospital, Brisbane, QLD, Australia
| | - B A Williams
- Department of Haematology, Lady Cilento Children's Hospital, Brisbane, QLD, Australia
| | - S A Brown
- Department of Haematology, Lady Cilento Children's Hospital, Brisbane, QLD, Australia
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Abstract
Due to progressive advances in surgical techniques, immunosuppressive therapies, and supportive care, outcomes from both solid organ transplantation and hematopoietic stem cell transplantation continue to improve. Thrombosis remains a challenging management issue in this context, with implications for both graft survival and long-term quality of life. Unfortunately, there remains a general paucity of pediatric-specific data regarding thrombosis incidence, risk stratification, and the safety or efficacy of preventative strategies with which to guide treatment algorithms. This review summarizes the available evidence and rationale underlying the spectrum of current practices aimed at preventing thrombosis in the transplant recipient, with a particular focus on risk factors, pathophysiology, and described antithrombotic regimens.
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Affiliation(s)
- J D Robertson
- Haematology Service, Division of Medicine, Lady Cilento Children's Hospital, Brisbane, Qld, Australia
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Khan A, Robertson JD, Narra V, Yue N, Howell R. SU-E-T-193: FMEA Severity Scores - Do We Really Know? Med Phys 2014. [DOI: 10.1118/1.4888523] [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: 11/07/2022] Open
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Mahajan IM, Chen MD, Muro I, Robertson JD, Wright CW, Bratton SB. BH3-only protein BIM mediates heat shock-induced apoptosis. PLoS One 2014; 9:e84388. [PMID: 24427286 PMCID: PMC3888412 DOI: 10.1371/journal.pone.0084388] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2013] [Accepted: 11/18/2013] [Indexed: 11/21/2022] Open
Abstract
Acute heat shock can induce apoptosis through a canonical pathway involving the upstream activation of caspase-2, followed by BID cleavage and stimulation of the intrinsic pathway. Herein, we report that the BH3-only protein BIM, rather than BID, is essential to heat shock-induced cell death. We observed that BIM-deficient cells were highly resistant to heat shock, exhibiting short and long-term survival equivalent to Bax−/−Bak−/− cells and better than either Bid−/− or dominant-negative caspase-9-expressing cells. Only Bim−/− and Bax−/−Bak−/− cells exhibited resistance to mitochondrial outer membrane permeabilization and loss of mitochondrial inner membrane potential. Moreover, while dimerized caspase-2 failed to induce apoptosis in Bid−/− cells, it readily did so in Bim−/− cells, implying that caspase-2 kills exclusively through BID, not BIM. Finally, BIM reportedly associates with MCL-1 following heat shock, and Mcl-1−/− cells were indeed sensitized to heat shock-induced apoptosis. However, pharmacological inhibition of BCL-2 and BCL-XL with ABT-737 also sensitized cells to heat shock, most likely through liberation of BIM. Thus, BIM mediates heat shock-induced apoptosis through a BAX/BAK-dependent pathway that is antagonized by antiapoptotic BCL-2 family members.
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Affiliation(s)
- Indra M. Mahajan
- The University of Texas MD Anderson Cancer Center, Science Park, Department of Molecular Carcinogenesis, Smithville, Texas, United States of America
- Division of Pharmacology and Toxicology, College of Pharmacy, The University of Texas at Austin, Austin, Texas, United States of America
| | - Miao-Der Chen
- The University of Texas MD Anderson Cancer Center, Science Park, Department of Molecular Carcinogenesis, Smithville, Texas, United States of America
- Division of Pharmacology and Toxicology, College of Pharmacy, The University of Texas at Austin, Austin, Texas, United States of America
| | - Israel Muro
- Division of Pharmacology and Toxicology, College of Pharmacy, The University of Texas at Austin, Austin, Texas, United States of America
| | - John D. Robertson
- Department of Pharmacology, Toxicology and Therapeutics, University of Kansas Medical Center, Kansas City, Kansas, United States of America
| | - Casey W. Wright
- Division of Pharmacology and Toxicology, College of Pharmacy, The University of Texas at Austin, Austin, Texas, United States of America
| | - Shawn B. Bratton
- The University of Texas MD Anderson Cancer Center, Science Park, Department of Molecular Carcinogenesis, Smithville, Texas, United States of America
- * E-mail:
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Jürgensmeier JM, Schmoll HJ, Robertson JD, Brooks L, Taboada M, Morgan SR, Wilson D, Hoff PM. Prognostic and predictive value of VEGF, sVEGFR-2 and CEA in mCRC studies comparing cediranib, bevacizumab and chemotherapy. Br J Cancer 2013; 108:1316-23. [PMID: 23449351 PMCID: PMC3619270 DOI: 10.1038/bjc.2013.79] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [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] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND The prognostic/predictive value of potential vascular endothelial growth factor (VEGF) signalling biomarkers was evaluated retrospectively using samples from two randomized Phase III studies (HORIZON II and III) investigating cediranib in metastatic colorectal cancer (mCRC). METHODS Baseline levels of VEGF, soluble VEGF receptor-2 (sVEGFR-2) and carcinoembryonic antigen (CEA) were measured in plasma/serum samples collected from patients participating in HORIZON II (n=860; FOLFOX/XELOX plus cediranib 20 mg (n=502) or placebo (n=358)) and HORIZON III (n=1422; mFOLFOX6 plus cediranib 20 mg (n=709) or bevacizumab (n=713)). Median biomarker baseline levels determined cutoff values for the patient subgroups. RESULTS Baseline data were available for 88-97% of patients/study (>2000 patients). In both the studies, high baseline VEGF and CEA were associated with worse outcomes for progression-free survival (PFS) and overall survival (OS) independent of treatment (HORIZON II OS: VEGF, hazard ratio (HR)=1.35 (95% confidence interval (CI): 1.12-1.63); CEA, HR=1.63 (1.36-1.96); HORIZON III OS: VEGF, HR=1.32 (1.12-1.54); CEA, HR=1.50 (1.29-1.76)). sVEGFR-2 was not prognostic for PFS/OS. Baseline VEGF and CEA were not predictive for PFS/OS outcome to cediranib treatment; low sVEGFR-2 was associated with a trend towards improved cediranib effect in HORIZON II. CONCLUSION Baseline VEGF and CEA levels were treatment-independent prognostic biomarkers for PFS and OS in both the studies.
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Affiliation(s)
- J M Jürgensmeier
- Translational Sciences, Oncology, AstraZeneca, Alderley Park, Macclesfield SK10 4TG, UK.
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Khem S, Young OA, Robertson JD, Brooks JD. Development of Model Fermented Fish Sausage from Marine Species: A Pilot Physicochemical Study. ACTA ACUST UNITED AC 2013. [DOI: 10.4236/fns.2013.412157] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Ottosson-Wadlund A, Ceder R, Preta G, Pokrovskaja K, Grafström RC, Heyman M, Söderhäll S, Grandér D, Hedenfalk I, Robertson JD, Fadeel B. Requirement of Apoptotic Protease-Activating Factor-1 for Bortezomib-Induced Apoptosis but Not for Fas-Mediated Apoptosis in Human Leukemic Cells. Mol Pharmacol 2012; 83:245-55. [PMID: 23093495 DOI: 10.1124/mol.112.080788] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Affiliation(s)
- Astrid Ottosson-Wadlund
- Division of Molecular Toxicology, Institute of Environmental Medicine, Nobels väg 13, Karolinska Institutet, 171 77 Stockholm, Sweden
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Wang Y, Robertson JD, Walcheck B. Different signaling pathways stimulate a disintegrin and metalloprotease-17 (ADAM17) in neutrophils during apoptosis and activation. J Biol Chem 2011; 286:38980-8. [PMID: 21949123 DOI: 10.1074/jbc.m111.277087] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
ADAM17 is a membrane-associated metalloprotease that cleaves proteins from the surface of neutrophils and modulates the density of various receptors and adhesion molecules. The protease activity of ADAM17 is highly inducible and occurs upon neutrophil activation as well as apoptosis. At this time, little is known about the signal transduction pathway that promotes ADAM17 activity in neutrophils upon the induction of apoptosis. We show that caspase-8 activation, Bid cleavage, and the release of mitochondrial reactive oxygen species are sequential transduction components of the Fas signaling cascade that induces ADAM17. This is different from ADAM17 stimulation upon overt neutrophil activation, which requires MAPK p38 or ERK, but not caspases and reactive oxygen species. ADAM17 activity in apoptotic neutrophils may serve to inactivate select effector molecules that promote the pro-inflammatory activity of recruited neutrophils. For instance, TNFα receptors TNF-RI and TNF-RII are substrates of ADAM17, and we show that they are shed during apoptosis, decreasing neutrophil sensitivity to TNFα. Altogether, our findings provide significant new insights into the signal transduction pathway that stimulates ADAM17 during induced neutrophil apoptosis. ADAM17 induction during apoptosis may rapidly diminish neutrophil sensitivity to the inflammatory environment, complementing other anti-inflammatory activities by these cells during inflammation resolution.
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Affiliation(s)
- Yue Wang
- Department of Veterinary and Biomedical Sciences, University of Minnesota, St. Paul, Minnesota 55108, USA
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Robertson JD, Yenson PR, Rand ML, Blanchette VS, Carcao MD, Notley C, Lillicrap D, James PD. Expanded phenotype-genotype correlations in a pediatric population with type 1 von Willebrand disease. J Thromb Haemost 2011; 9:1752-60. [PMID: 21711445 DOI: 10.1111/j.1538-7836.2011.04423.x] [Citation(s) in RCA: 11] [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] [Indexed: 11/27/2022]
Abstract
BACKGROUND Recent phenotype-genotype studies have provided valuable insights into the pathophysiology of type 1 von Willebrand disease (VWD); however, no study has examined an exclusively pediatric cohort. OBJECTIVES To describe phenotype-genotype correlations in a selected pediatric cohort with a historical diagnosis of type 1 VWD, using first-degree family members as controls. METHODS Comprehensive phenotypic assessment included standard assays of von Willebrand factor (VWF) level and function, bleeding score, desmopressin response, VWF propeptide (VWFpp) level, and platelet-derived VWF mRNA level. RESULTS Fourteen VWF mutations were identified in 17 of 23 index cases (ICs) (aged 5-17 years), including four that were previously unreported (L60P, nt1658 insT, Q1388X, and C2237F). VWFpp levels were lower in ICs than in unaffected controls (median 49 vs. 86 U dL(-1) , P < 0.0001). A VWFpp/VWF antigen ratio of > 1.6 was observed in eight of nine ICs with a suboptimal response to desmopressin, including four of four with the R1205H (Vicenza) mutation (median 7.9), and three of four IC with the R1315C mutation (median 1.9). The R1315C mutation was also associated with a reduced absolute VWFpp level (median 32 U dL(-1) ), a previously unreported finding. The amount of platelet-derived VWF mRNA was significantly reduced in individuals with nonsense mutations. CONCLUSIONS Increased VWF clearance and intracellular retention are important mechanisms underlying type 1 VWD in pediatric patients, concordant with the observations of larger, predominantly adult, cohort studies. Additionally, in some patients, nonsense-mediated decay of mutant mRNA transcripts may be contributory. Several mechanisms underlie the variable phenotype associated with the R1315C mutation. The potential utility of VWFpp as an independent marker of VWF biosynthesis and release warrants further research.
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Affiliation(s)
- J D Robertson
- Haematology Service, Division of Oncology, Royal Children's Hospital Department of Haematology, Pathology Queensland, Brisbane, QLD, Australia.
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Selting KA, Wang X, Gustafson DL, Henry CJ, Villamil JA, McCaw DL, Tate D, Beittenmiller M, Garnett C, Robertson JD. Evaluation of satraplatin in dogs with spontaneously occurring malignant tumors. J Vet Intern Med 2011; 25:909-15. [PMID: 21564292 DOI: 10.1111/j.1939-1676.2011.0727.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND Satraplatin is the 1st orally bioavailable platinum anticancer drug. OBJECTIVE Our objectives were to evaluate efficacy in vitro against a canine cancer cell line, to determine the maximally tolerated dose (MTD) of satraplatin in tumor-bearing dogs, to identify the dose-limiting and other toxicities in dogs, and to record pharmacokinetics (PK). ANIMALS Dogs with macro- or microscopic malignant neoplasia. METHODS D17 canine osteosarcoma cells first were evaluated in a clonogenic survival assay. Then, dogs with a diagnosis of malignant neoplasia were prospectively entered in standard 3 + 3 cohorts. Additional patients were entered at the MTD to assess efficacy. Total and free platinum (by ultrafiltrate) concentrations were determined with inductively coupled plasma mass spectroscopy. RESULTS Satraplatin inhibited clonogenic survival in vitro at clinically relevant and achievable concentrations. Twenty-three dogs were treated, 14 with PK evaluation. The MTD was 35 mg/m(2)/d for 5 days, repeated every 3-4 weeks. Bioavailability was 41%. PK variables (mean ± SD) at the MTD included T(max) 1.8 (± 0.7) hours, C(max) 72 (± 26) ng/mL, area under concentration (AUC)(0-24 h) 316 (± 63) h × ng/mL, and MRT 7 (± 1.3) hours. Higher AUC after the 5th versus the 1st dose suggested drug accumulation. Interestingly, platelets consistently reached nadir sooner than did neutrophils (day 14 versus 19). Myelosuppression was dose-limiting and gastrointestinal toxicity was mild. CONCLUSIONS AND CLINICAL IMPORTANCE Satraplatin was well tolerated in tumor-bearing dogs, thus warranting further investigation in a phase II trial.
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Affiliation(s)
- K A Selting
- Department of Veterinary Medicine, University of Missouri, Columbia, MO 65211, USA.
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Shelton SN, Dillard CD, Robertson JD. Activation of caspase-9, but not caspase-2 or caspase-8, is essential for heat-induced apoptosis in Jurkat cells. J Biol Chem 2010; 285:40525-33. [PMID: 20978129 DOI: 10.1074/jbc.m110.167635] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Exposure of cells to hyperthermia is known to induce apoptosis, although the underlying mechanisms are only partially understood. Here, we examine the molecular requirements necessary for heat-induced apoptosis using genetically modified Jurkat T-lymphocytes. Cells stably overexpressing Bcl-2/Bcl-x(L) or stably depleted of Apaf-1 were completely resistant to heat-induced apoptosis, implicating the involvement of the mitochondria-mediated pathway. Pretreatment of wild-type cells with the cell-permeable biotinylated general caspase inhibitor b-VAD-fmk (biotin-Val-Ala-Asp(OMe)-CH(2)F) both inhibited heat-induced apoptosis and affinity-labeled activated initiator caspase-2, -8, and -9. Despite this finding, however, cells engineered to be deficient in caspase-8, caspase-2, or the caspase-2 adaptor protein RAIDD (receptor-interacting protein (RIP)-associated Ich-1/CED homologous protein with death domain) remained susceptible to heat-induced apoptosis. Additionally, b-VAD-fmk failed to label any activated initiator caspase in Apaf-1-deficient cells exposed to hyperthermia. Cells lacking Apaf-1 or the pro-apoptotic BH3-only protein Bid exhibited lower levels of heat-induced Bak activation, cytochrome c release, and loss of mitochondrial membrane potential, although cleavage of Bid to truncated Bid (tBid) occurred downstream of caspase-9 activation. Combined, the data suggest that caspase-9 is the critical initiator caspase activated during heat-induced apoptosis and that tBid may function to promote cytochrome c release during this process as part of a feed-forward amplification loop.
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Affiliation(s)
- Shary N Shelton
- Department of Pharmacology, Toxicology and Therapeutics, University of Kansas Medical Center, Kansas City, Kansas 66160, USA
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Chiu A, Shi XL, Lee WKP, Hill R, Wakeman TP, Katz A, Xu B, Dalal NS, Robertson JD, Chen C, Chiu N, Donehower L. Review of chromium (VI) apoptosis, cell-cycle-arrest, and carcinogenesis. J Environ Sci Health C Environ Carcinog Ecotoxicol Rev 2010; 28:188-230. [PMID: 20859824 PMCID: PMC4330561 DOI: 10.1080/10590501.2010.504980] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Hexavalent chromium combines with glutathione in chloride intracellular channel carrier to form tetravalent and pentavalent chromium in plasma and organelle membranes. It also combines with NADH/NADPH to form pentavalent chromium in mitochondria. Tetravalent- and pentavalent- chromium (directly and indirectly) mediated DNA double strand breaks activate DNA damage signaling sensors: DNA-dependent-protein-kinase signals p53-dependent intrinsic mitochondrial apoptosis, and ataxia-telangiectasia-mutated and ataxia-telangiectasia-Rad3-related signal cell-arrest for DNA repair. Tetravalent chromium may be the most potent species since it causes DNA breaks and somatic recombination, but not apoptosis. Upon further failure of apoptosis and senescence/DNA-repair, damaged cells may become immortal with loss-of-heterozygosity and genetic plasticity.
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Affiliation(s)
- A Chiu
- National Center for Environmental Assessment DC, US Environmental Protection Agency, Washington, DC 20460, USA.
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Shawgo ME, Shelton SN, Robertson JD. Caspase-9 activation by the apoptosome is not required for fas-mediated apoptosis in type II Jurkat cells. J Biol Chem 2009; 284:33447-55. [PMID: 19758996 DOI: 10.1074/jbc.m109.032359] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Activation of executioner caspases during receptor-mediated apoptosis in type II cells requires the engagement of the mitochondrial apoptotic pathway. Although it is well established that recruitment of mitochondria in this context involves the cleavage of Bid to truncated Bid (tBid), the precise post-mitochondrial signaling responsible for executioner caspase activation is controversial. Here, we used distinct clones of type II Jurkat T-lymphocytes in which the mitochondrial apoptotic pathway had been inhibited to investigate the molecular requirements necessary for Fas-induced apoptosis. Cells overexpressing either Bcl-2 or Bcl-x(L) were protected from apoptosis induced by agonistic anti-Fas antibody. By comparison, Apaf-1-deficient Jurkat cells were sensitive to anti-Fas, exhibiting Bid cleavage, Bak activation, the release of cytochrome c and Smac, and activation of executioner caspase-3. Inhibiting downstream caspase activation with the pharmacological inhibitor Z-DEVD-fmk or by expressing the BIR1/BIR2 domains of X-linked inhibitor of apoptosis protein (XIAP) decreased all anti-Fas-induced apoptotic changes. Additionally, pretreatment of Bcl-x(L)-overexpressing cells with a Smac mimetic sensitized these cells to Fas-induced apoptosis. Combined, our findings strongly suggest that Fas-mediated activation of executioner caspases and induction of apoptosis do not depend on apoptosome-mediated caspase-9 activation in prototypical type II cells.
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Affiliation(s)
- Mary E Shawgo
- Department of Pharmacology, Toxicology & Therapeutics and the Kansas University Cancer Center, University of Kansas Medical Center, Kansas City, Kansas 66160, USA
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Shelton SN, Shawgo ME, Matthews SB, Lu Y, Donnelly AC, Szabla K, Tanol M, Vielhauer GA, Rajewski RA, Matts RL, Blagg BSJ, Robertson JD. KU135, a novel novobiocin-derived C-terminal inhibitor of the 90-kDa heat shock protein, exerts potent antiproliferative effects in human leukemic cells. Mol Pharmacol 2009; 76:1314-22. [PMID: 19741006 DOI: 10.1124/mol.109.058545] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The 90-kDa heat shock protein (Hsp90) assists in the proper folding of numerous mutated or overexpressed signal transduction proteins that are involved in cancer. Consequently, there is considerable interest in developing chemotherapeutic drugs that specifically disrupt the function of Hsp90. Here, we investigated the extent to which a novel novobiocin-derived C-terminal Hsp90 inhibitor, designated KU135, induced antiproliferative effects in Jurkat T-lymphocytes. The results indicated that KU135 bound directly to Hsp90, caused the degradation of known Hsp90 client proteins, and induced more potent antiproliferative effects than the established N-terminal Hsp90 inhibitor 17-allylamino-demethoxygeldanamycin (17-AAG). Closer examination of the cellular response to KU135 and 17-AAG revealed that only 17-AAG induced a strong up-regulation of Hsp70 and Hsp90. In addition, KU135 caused wild-type cells to undergo G(2)/M arrest, whereas cells treated with 17-AAG accumulated in G(1). Furthermore, KU135 but not 17-AAG was found to be a potent inducer of mitochondria-mediated apoptosis as evidenced, in part, by the fact that cell death was inhibited to a similar extent by Bcl-2/Bcl-x(L) overexpression or the depletion of apoptotic protease-activating factor-1 (Apaf-1). Together, these data suggest that KU135 inhibits cell proliferation by regulating signaling pathways that are mechanistically different from those targeted by 17-AAG and as such represents a novel opportunity for Hsp90 inhibition.
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Affiliation(s)
- Shary N Shelton
- Department of Pharmacology, Toxicology and Therapeutics, University of Kansas Medical Center, Kansas City, KS, USA
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Kavetskiy A, Yakubova G, Lin Q, Chan D, Yousaf SM, Bower K, Robertson JD, Garnov A, Meier D. Promethium-147 capacitor. Appl Radiat Isot 2009; 67:1057-62. [PMID: 19328703 DOI: 10.1016/j.apradiso.2009.02.084] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2008] [Revised: 02/16/2009] [Accepted: 02/18/2009] [Indexed: 11/16/2022]
Abstract
Beta particle surface fluxes for tritium, Ni-63, Pm-147, and Sr-90 sources were calculated in this work. High current density was experimentally achieved from Pm-147 oxide in silica-titana glass. A 96 GBq (2.6 Ci) Pm-147 4pi-source with flux efficiency greater than 50% was used for constructing a direct charge capacitor with a polyimide coated collector and vacuum as electrical insulation. The capacitor connected to high resistance (TOmega) loads produced up to 35 kV. Overall conversion efficiency was over 10% (on optimal load).
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Affiliation(s)
- A Kavetskiy
- TRACE Photonics Inc., 1680 West Polk Avenue, Charleston, Illinois 61920, USA
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Brockman JD, Robertson JD. Analysis of k0 neutron activation analysis at the University of Missouri Research Reactor. Appl Radiat Isot 2009; 67:1084-8. [PMID: 19231216 DOI: 10.1016/j.apradiso.2009.01.070] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2008] [Revised: 01/07/2009] [Accepted: 01/12/2009] [Indexed: 10/21/2022]
Abstract
k(0) Instrumental Neutron Activation Analysis (k(0) INAA) was evaluated at the University of Missouri Research Reactor (MURR). The MURR, unlike many other research reactors that employ k(0) INAA, is refueled on a weekly basis. To determine if the neutron spectrum is stable enough for routine k(0) INAA analysis, the neutron spectrum parameters alpha and f were measured over a 9 month period. The average values of f and alpha measured using the Cd ratio multi monitor technique were 57.4+/-4.5 and 0.039+/-0.012, respectively. It was determined that k(0) INAA could be used at the MURR by employing the average value of alpha and f. However, significant measurement bias could occur for elements with high Q(0) values if the true spectral parameters deviate by more than 10% from the average value.
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Affiliation(s)
- J D Brockman
- Department of Chemistry, University of Missouri, 601 S College Ave., Columbia, MO 65211, USA.
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Shelton SN, Shawgo ME, Robertson JD. Cleavage of Bid by executioner caspases mediates feed forward amplification of mitochondrial outer membrane permeabilization during genotoxic stress-induced apoptosis in Jurkat cells. J Biol Chem 2009; 284:11247-55. [PMID: 19233849 DOI: 10.1074/jbc.m809392200] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
The extent to which the BH3-only protein Bid is important for intrinsic (mitochondria-mediated) apoptotic cell death induced by genotoxic stress remains controversial. In the present study, we examine this issue using a panel of gene-manipulated Bax-deficient Jurkat T-lymphocytes. Cells stably depleted of Bid were far less sensitive than control-transfected cells to etoposide-induced apoptosis. In particular, drug-induced Bak activation, cytochrome c release, loss of mitochondrial membrane potential, and caspase activation were all decreased in cells lacking Bid. Reconstitution experiments using recombinant proteins and permeabilized Bid-deficient cells demonstrated that truncated Bid (tBid), but not full-length Bid, potently induced Bak activation and the release of cytochrome c. Further, caspase-8-deficient Jurkat cells efficiently cleaved Bid and were sensitive to drug-induced apoptosis. By comparison, Apaf-1-deficient cells, as well as cells overexpressing full-length X-linked inhibitor of apoptosis protein (XIAP) or the BIR1/BIR2 domains of XIAP, failed to cleave Bid in response to genotoxic stress. These data suggest that tBid plays an important regulatory role in the execution of DNA damage-induced cytochrome c release and apoptosis. However, the fact that cleavage of Bid to tBid is mediated by executioner caspases suggests that a self-amplifying feed forward loop involving caspases, Bid, and mitochondria may help determine irreversible commitment to apoptosis.
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Affiliation(s)
- Shary N Shelton
- Department of Pharmacology, Toxicology & Therapeutics and the Kansas University Cancer Center, University of Kansas Medical Center, Kansas City, Kansas 66160, USA
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Hillman LS, Cassidy JT, Chanetsa F, Hewett JE, Higgins BJ, Robertson JD. Percent true calcium absorption, mineral metabolism, and bone mass in children with arthritis: effect of supplementation with vitamin D3 and calcium. ACTA ACUST UNITED AC 2008; 58:3255-63. [PMID: 18821668 DOI: 10.1002/art.23809] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
OBJECTIVE To assess whether percent true calcium absorption (alpha) is normal and whether supplementation with placebo, vitamin D3 (2,000 IU/day), calcium (1,000 mg/day), or vitamin D3 plus calcium improves alpha, mineral metabolism, or bone mass accrual in children with arthritis. METHODS Eighteen children received all 4 treatments, each for 6 months, in 4 different, randomly assigned orders. Changes in levels of 25-hydroxyvitamin D (25[OH]D), 1,25-dihydroxyvitamin D (1,25[OH]2D), parathyroid hormone, bone turnover markers, and minerals and in bone mineral content were measured. Calcium absorption was determined with a dual stable isotope method using 48Ca administered intravenously and 46Ca administered orally, and measuring 48Ca, 46Ca, and 42Ca in a 24-hour urine specimen by high-resolution inductively coupled plasma mass spectroscopy. Wilcoxon's signed rank test was used both to identify significant change over the treatment period with a given regimen and to compare change with an experimental treatment versus change with placebo. RESULTS Percent true calcium absorption was in the lower-normal range and did not differ by treatment (mean+/-SD 28.3+/-20.2% with placebo, 26.1+/-12.1% with calcium, 19.2+/-11.7% with vitamin D3, and 27.1+/-16.5% with vitamin D3 plus calcium). With vitamin D3 and vitamin D3 plus calcium treatment, 25(OH)D levels were increased and 1,25(OH)2D levels were maintained. Serum calcium levels were increased only with vitamin D3 and vitamin D3 plus calcium treatment. Levels of bone turnover markers and increases in bone mineral content did not differ by treatment. CONCLUSION The findings of this study indicate that percent true calcium absorption is low-normal in children with arthritis. Vitamin D3 at 2,000 IU/day increases serum 25(OH)D and calcium levels but does not improve bone mass accretion. Calcium at 1,000 mg/day also failed to improve bone mass.
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Affiliation(s)
- Laura S Hillman
- Department of Child Health, University of Missouri, Columbia, MO 65212, USA.
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Shawgo ME, Shelton SN, Robertson JD. Caspase-mediated Bak activation and cytochrome c release during intrinsic apoptotic cell death in Jurkat cells. J Biol Chem 2008; 283:35532-8. [PMID: 18927073 DOI: 10.1074/jbc.m807656200] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Mitochondrial outer membrane permeabilization and the release of intermembrane space proteins, such as cytochrome c, are early events during intrinsic (mitochondria-mediated) apoptotic signaling. Although this process is generally accepted to require the activation of Bak or Bax, the underlying mechanism responsible for their activation during true intrinsic apoptosis is not well understood. In the current study, we investigated the molecular requirements necessary for Bak activation using distinct clones of Bax-deficient Jurkat T-lymphocytes in which the intrinsic pathway had been inhibited. Cells stably overexpressing Bcl-2/Bcl-x(L) or stably depleted of Apaf-1 were equally resistant to apoptosis induced by the DNA-damaging anticancer drug etoposide as determined by phosphatidylserine externalization and caspase activation. Strikingly, characterization of mitochondrial apoptotic events in all three drug-resistant cell lines revealed that, without exception, resistance to apoptosis was associated with an absence of Bak activation, cytochrome c release, and mitochondrial membrane depolarization. Furthermore, we found that etoposide-induced apoptosis and mitochondrial events were inhibited in cells stably overexpressing either full-length X-linked inhibitor of apoptosis protein (XIAP) or the BIR1/BIR2 domains of XIAP. Combined, our findings suggest that caspase-mediated positive amplification of initial mitochondrial changes can determine the threshold for irreversible activation of the intrinsic apoptotic pathway.
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Affiliation(s)
- Mary E Shawgo
- Department of Pharmacology, University of Kansas Medical Center, Kansas City, Kansas 66160, USA
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Affiliation(s)
- J D Robertson
- Courtauld Institute Of Biochemistry, Middlesex Hospital, W.1
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Affiliation(s)
- G Mackay
- Consulting Ophthalmic Surgeon to the Royal Infirmary, Edinburgh
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Affiliation(s)
- J D Robertson
- London, Courtauld Institute of Biochemistry, Middlesex Hospital, W.1
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30
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Affiliation(s)
- J D Robertson
- London, Courtauld Institute Of Biochemistry, Middlesex Hospital, W.1
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Robertson JD. The effect of haemorrhage of varying degree on blood and plasma volume, on blood sugar, and on arterial blood-pressure. J Physiol 2007; 84:393-409. [PMID: 16994687 PMCID: PMC1394474 DOI: 10.1113/jphysiol.1935.sp003289] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
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Robertson JD, Williams PC. The creatinine, sugar, and urea equilibrium between plasma and lymph, aqueous humour, cerebro-spinal fluid, and gastric secretion after a hypertonic injection of these solutions. J Physiol 2007; 95:139-47. [PMID: 16995070 PMCID: PMC1393969 DOI: 10.1113/jphysiol.1939.sp003715] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
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34
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Affiliation(s)
- J D Robertson
- The Departments of Forensic Medicine and Medical Chemistry, University of Edinburgh
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Affiliation(s)
- J D Robertson
- HARVARD MEDICAL SCHOOL, RESEARCH LABORATORY, MCLEAN HOSPITAL, BELMONT, MASSACHUSETTS
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Enoksson M, Robertson JD, Gogvadze V, Bu P, Kropotov A, Zhivotovsky B, Orrenius S. Caspase-2 Permeabilizes the Outer Mitochondrial Membrane and Disrupts the Binding of Cytochrome c to Anionic Phospholipids. J Biol Chem 2004; 279:49575-8. [PMID: 15475367 DOI: 10.1074/jbc.c400374200] [Citation(s) in RCA: 93] [Impact Index Per Article: 4.7] [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
Caspases are cysteine proteases that play a central role in the execution of apoptosis. Recent evidence indicates that caspase-2 is activated early in response to genotoxic stress and can function as an upstream modulator of the mitochondrial apoptotic pathway. In particular, we have shown previously that fully processed caspase-2 can permeabilize the outer mitochondrial membrane and cause cytochrome c and Smac/DIABLO release from these organelles. Using permeabilized cells, isolated mitochondria, and protein-free liposomes, we now report that this effect is direct and depends neither on the presence or cleavage of other proteins nor on a specific phospholipid composition of the liposomal membrane. Interestingly, caspase-2 was also shown to disrupt the interaction of cytochrome c with anionic phospholipids, notably cardiolipin, and thereby enhance the release of the hemoprotein caused by treatment of mitochondria with digitonin or the proapoptotic protein Bax. Combined, our data suggest that caspase-2 possesses an unparalleled ability to engage the mitochondrial apoptotic pathway by permeabilizing the outer mitochondrial membrane and/or by breaching the association of cytochrome c with the inner mitochondrial membrane.
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Affiliation(s)
- Mari Enoksson
- Division of Toxicology, Institute of Environmental Medicine, Karolinska Institutet, Box 210, SE-171 77 Stockholm, Sweden
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Robertson JD, Gogvadze V, Kropotov A, Vakifahmetoglu H, Zhivotovsky B, Orrenius S. Processed caspase-2 can induce mitochondria-mediated apoptosis independently of its enzymatic activity. EMBO Rep 2004; 5:643-8. [PMID: 15153933 PMCID: PMC1299073 DOI: 10.1038/sj.embor.7400153] [Citation(s) in RCA: 99] [Impact Index Per Article: 5.0] [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: 01/05/2004] [Revised: 03/04/2004] [Accepted: 03/30/2004] [Indexed: 12/21/2022] Open
Abstract
The mechanism by which caspase-2 executes apoptosis remains obscure. Recent findings indicate that caspase-2 is activated early in response to DNA-damaging antineoplastic agents and may be important for the engagement of the mitochondrial apoptotic pathway. We demonstrate here that fully processed caspase-2 stimulates mitochondrial release of cytochrome c and Smac/DIABLO, but not apoptosis-inducing factor (AIF). This event occurs independently of several Bcl-2 family proteins, including Bax, Bak and Bcl-2, and inactivation experiments reveal that the proteolytic activity of caspase-2 is not required for the effect. Further, functional studies of mitochondria indicate that processed caspase-2 stimulates state 4 respiration and decreases the respiratory control ratio as a result of, in large part, an uncoupling effect. Combined, our data suggest that caspase-2 retains a unique ability to engage directly the mitochondrial apoptotic pathway, an effect that requires processing of the zymogen but not the associated catalytic activity.
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Affiliation(s)
- John D Robertson
- Division of Toxicology, Institute of Environmental Medicine, Karolinska Institutet, 171 77 Stockholm, Sweden
- Present address: Department of Pharmacology, Toxicology and Therapeutics, University of Kansas Medical Center, 3901 Rainbow Boulevard, Kansas City, Kansas 66160, USA
- Tel: +1 913 588 0383; Fax: +1 913 588 7501; E-mail:
| | - Vladimir Gogvadze
- Division of Toxicology, Institute of Environmental Medicine, Karolinska Institutet, 171 77 Stockholm, Sweden
| | - Andrey Kropotov
- Division of Toxicology, Institute of Environmental Medicine, Karolinska Institutet, 171 77 Stockholm, Sweden
| | - Helin Vakifahmetoglu
- Division of Toxicology, Institute of Environmental Medicine, Karolinska Institutet, 171 77 Stockholm, Sweden
| | - Boris Zhivotovsky
- Division of Toxicology, Institute of Environmental Medicine, Karolinska Institutet, 171 77 Stockholm, Sweden
| | - Sten Orrenius
- Division of Toxicology, Institute of Environmental Medicine, Karolinska Institutet, 171 77 Stockholm, Sweden
- Tel: +46 8 33 58 74; Fax: +46 8 32 90 41; E-mail:
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Tamm C, Robertson JD, Sleeper E, Enoksson M, Emgård M, Orrenius S, Ceccatelli S. Differential regulation of the mitochondrial and death receptor pathways in neural stem cells. Eur J Neurosci 2004; 19:2613-21. [PMID: 15147295 DOI: 10.1111/j.0953-816x.2004.03391.x] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.2] [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: 11/28/2022]
Abstract
Despite an increasing interest in neural stem cell (NSC) research, relatively little is known about the biochemical regulation of cell death pathways in these cells. We demonstrate here, using murine-derived multipotent C17.2 NSCs, that cells undergo mitochondria-mediated cell death in response to apoptotic stimuli such as oxidative stress induced by 2,3-dimethoxy-1,4-naphthoquinone (DMNQ). In particular, treated cells exhibited apoptotic features, including Bax translocation, cytochrome c release, activation of caspase-9 and -3, chromatin condensation and DNA fragmentation. Although C17.2 cells possess the Fas receptor and express procaspase-8, agonistic Fas mAb treatment failed to induce apoptosis. Fas treatment activated the extracellular signal-regulated protein kinase (ERK) pathway, which may have an antiapoptotic as well as a growth stimulating role. Combined, our findings indicate that while NSCs are sensitive to cytotoxic stimuli that involve an engagement of mitochondria, Fas treatment does not induce death and may have an alternative role.
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Affiliation(s)
- Christoffer Tamm
- Institute of Environmental Medicine, Division of Toxicology and Neurotoxicology, Karolinska Institutet, 71 77 Stockholm, Sweden
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39
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Gogvadze V, Robertson JD, Enoksson M, Zhivotovsky B, Orrenius S. Mitochondrial cytochrome c release may occur by volume-dependent mechanisms not involving permeability transition. Biochem J 2004; 378:213-7. [PMID: 14629197 PMCID: PMC1223940 DOI: 10.1042/bj20031193] [Citation(s) in RCA: 49] [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: 08/07/2003] [Revised: 11/14/2003] [Accepted: 11/20/2003] [Indexed: 11/17/2022]
Abstract
The mechanisms regulating mitochondrial outer-membrane permeabilization and the release of cytochrome c during apoptosis remain controversial. In the present study, we show in an in vitro model system that the release of cytochrome c may occur via moderate modulation of mitochondrial volume, irrespective of the mechanism leading to the mitochondrial swelling. In contrast with mitochondrial permeability transition-dependent release of cytochrome c, in the present study mitochondria remain intact and functionally active.
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Affiliation(s)
- Vladimir Gogvadze
- Division of Toxicology, Institute of Environmental Medicine, Karolinska Institutet, Box 210, SE-171 77 Stockholm, Sweden
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Lewis AL, Furze JD, Small S, Robertson JD, Higgins BJ, Taylor S, Ricci DR. Long-term stability of a coronary stent coating post-implantation. J Biomed Mater Res 2003; 63:699-705. [PMID: 12418013 DOI: 10.1002/jbm.10387] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
A coronary stent possessing a phosphorylcholine-based polymer coating was removed from a human patient 6 months after implantation and analyzed for the presence of the coating. An atomic force microscopy (AFM) technique has been employed to scrape away several 10- micro m(2) areas on the struts of the explanted stent. Scanning-electron microscopy (SEM) and tapping-mode AFM confirmed a surface coating had been removed in each case. Cross-sectional analysis and force-of-removal measurements showed that both coating depth and hardness were characteristic of that for the phosphorylcholine- (PC-) based coating prior to implantation. AFM amplitude-phase and distance curves from the explanted stent were comparable to those obtained when an unused stent was analyzed. Furthermore, laser ablation high-resolution inductively coupled-plasma mass spectometery (LA-HR-ICP-MS) was used to detect the low level of silicon present in the PC coating after explantation. The results from these techniques confirm that the stent coating is the original PC polymer and is not of biological origin, and support the long-term stability of the coating in vivo.
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Affiliation(s)
- A L Lewis
- Biocompatibles Ltd, Farnham, Surrey, GU9 8QL, United Kingdom.
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41
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Robertson JD, Zhivotovsky B, Gogvadze V, Orrenius S. Outer mitochondrial membrane permeabilization: an open-and-shut case? Cell Death Differ 2003; 10:485-7. [PMID: 12728245 DOI: 10.1038/sj.cdd.4401218] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
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42
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Ewing JC, Robertson JD, Kell WJ, Burnett AK, Ryder D, Chang J, Morgenstern GR, Scarffe JH, Chopra R. Autologous peripheral blood stem cell transplantation in first remission adult acute myeloid leukaemia--an intention to treat analysis and comparison of outcome using a predictive model based on the MRC AML10 cohort. Hematology 2003; 8:83-90. [PMID: 12745657 DOI: 10.1080/1024533031000090793] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [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: 10/26/2022] Open
Abstract
The role of autologous peripheral blood stem cell transplantation (APBSCT) in acute myeloid leukaemia (AML) remains controversial. The current study evaluated the application of APBSCT in a large consecutive series of patients with untreated AML, and compared outcome with a predictive model based on MRC AML10 data. Of 148 evaluable patients, 118 patients entered complete remission (CR) after induction therapy comprising three cycles of daunorubicin, cytosine arabinoside and oral 6-thioguanine. Of these patients, 68 (57%) proceeded to consolidation therapy with two courses of intermediate dose cytosine arabinoside, and stem cell mobilisation, and 40 of these patients (34%) underwent the APBSCT procedure after high dose busulphan conditioning. Harvest quality was the main factor precluding APBSCT. Five-year event-free survival (EFS) in patients who achieved CR was 38% and in APBSCT patients was 57%. There were no transplant-related deaths. No significant differences were demonstrated between observed and expected outcomes at 1 and 2 years, based on the predictive model derived from the MRC AML10 study. These data therefore indicate that only a third of eligible adult patients will undergo APBSCT. However, the results demonstrate favourable survival in such patients, with no transplant-related mortality.
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Affiliation(s)
- J C Ewing
- Department of Haematological Oncology, Christie Hospital, Manchester M20 4BX, UK.
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Abstract
Apoptosis is a highly regulated form of cell death distinguished by the activation of a family of cysteine-aspartate proteases (caspases) that cleave various proteins resulting in morphological and biochemical changes characteristic of this form of cell death. Abundant evidence supports a role for mitochondria in regulating apoptosis. Specifically, it seems that a number of death triggers target these organelles and stimulate, by an unknown mechanism, the release of several proteins, including cytochrome c. Once released into the cytosol, cytochrome c binds to its adaptor molecule, apoptotic protease activating factor-1, which oligomerizes and then activates pro-caspase-9. Caspase-9 can signal downstream and activate pro-caspase-3 and -7. The release of cytochrome c can be influenced by different Bcl-2 family member proteins, including Bax, Bid, Bcl-2, and Bcl-X(L). Bax and Bid potentiate cytochrome c release, whereas Bcl-2 and Bcl-X(L) antagonize this event. Although toxicologists have traditionally associated cell death with necrosis, emerging evidence suggests that different types of environmental contaminants exert their toxicity, at least in part, by triggering apoptosis. The mechanism responsible for eliciting the pro-apoptotic effect of a given chemical is often unknown, although in many instances mitochondria appear to be key participants. Here, we provide an overview of our current understanding of the role of apoptosis in toxicant-induced cell death, using dioxin, organotin compounds, dithiocarbamates, as well as the chemotherapeutic agent etoposide, as specific examples.
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Affiliation(s)
- John D Robertson
- Division of Toxicology, Institute of Environmental Medicine, Karolinska Institutet, Box 210, SE-171 77 Stockholm, Sweden
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44
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Affiliation(s)
- Matthew M. Matlock
- Department of Chemistry, University of Kentucky, Lexington, Kentucky 40506, and Department of Chemistry, University of MissouriColumbia, Columbia, Missouri 65211
| | - Brock S. Howerton
- Department of Chemistry, University of Kentucky, Lexington, Kentucky 40506, and Department of Chemistry, University of MissouriColumbia, Columbia, Missouri 65211
| | - John D. Robertson
- Department of Chemistry, University of Kentucky, Lexington, Kentucky 40506, and Department of Chemistry, University of MissouriColumbia, Columbia, Missouri 65211
| | - David A. Atwood
- Department of Chemistry, University of Kentucky, Lexington, Kentucky 40506, and Department of Chemistry, University of MissouriColumbia, Columbia, Missouri 65211
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Robertson JD, Enoksson M, Suomela M, Zhivotovsky B, Orrenius S. Caspase-2 acts upstream of mitochondria to promote cytochrome c release during etoposide-induced apoptosis. J Biol Chem 2002; 277:29803-9. [PMID: 12065594 DOI: 10.1074/jbc.m204185200] [Citation(s) in RCA: 313] [Impact Index Per Article: 14.2] [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: 01/12/2023] Open
Abstract
DNA damage induced by the cancer chemotherapeutic drug etoposide triggers the onset of a series of intracellular events characteristic of apoptosis. Among the early changes observed is the release of cytochrome c from mitochondria, although the mechanism responsible for this effect is unclear. We demonstrate here a role for caspase-2 in etoposide-induced cytochrome c release. In particular, Jurkat T-lymphocytes treated with an irreversible caspase-2 inhibitor, benzyloxycarbonyl-Val-Asp-Val-Ala-Asp-fluoromethyl ketone (z-VDVAD-fmk), or stably transfected with pro-caspase-2 antisense (Casp-2/AS) are refractory to cytochrome c release stimulated by etoposide. Experiments performed using a reconstituted cell-free system indicate that etoposide-induced cytochrome c release by way of caspase-2 occurs independently of cytosolic factors, suggesting that the nuclear pool of pro-caspase-2 is critical to this process. Apart from inhibiting cytochrome c release, undermining caspase-2 activity results in an attenuation of downstream events, such as pro-caspase-9 and -3 activation, phosphatidylserine exposure on the plasma membrane, and DNA fragmentation. Taken together, our data indicate that caspase-2 provides an important link between etoposide-induced DNA damage and the engagement of the mitochondrial apoptotic pathway.
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Affiliation(s)
- John D Robertson
- Division of Toxicology, Institute of Environmental Medicine, Karolinska Institutet, Box 210, SE-171 77 Stockholm, Sweden.
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Affiliation(s)
- J D Robertson
- Division of Toxicology, Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden
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Affiliation(s)
- J D Robertson
- Division of Toxicology, Institute of Environmental Medicine, Karolinska Institutet, SE-171 77 Stockholm, Sweden
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Robertson JD, Zhivotovsky B. New methodology is a key to progress. Cell Cycle 2002; 1:119-21. [PMID: 12429919] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/27/2023] Open
Affiliation(s)
- John D Robertson
- Division of Toxicology; Institute of Environmental Medicine; Karolinska Institutet; Box 210;SE-171 77 Stockholm, Sweden
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Abstract
Cytochrome c is often released from mitochondria during the early stages of apoptosis, although the precise mechanisms regulating this event remain unclear. In this study, with isolated liver mitochondria, we demonstrate that cytochrome c release requires a two-step process. Because cytochrome c is present as loosely and tightly bound pools attached to the inner membrane by its association with cardiolipin, this interaction must first be disrupted to generate a soluble pool of this protein. Specifically, solubilization of cytochrome c involves a breaching of the electrostatic and/or hydrophobic affiliations that this protein usually maintains with cardiolipin. Once cytochrome c is solubilized, permeabilization of the outer mitochondrial membrane by Bax is sufficient to allow the extrusion of this protein into the extramitochondrial environment. Neither disrupting the interaction of cytochrome c with cardiolipin, nor permeabilizing the outer membrane with Bax, alone, is sufficient to trigger this protein's release. This mechanism also extends to conditions of mitochondrial permeability transition insofar as cytochrome c release is significantly depressed when the electrostatic interaction between cytochrome c and cardiolipin remains intact. Our results indicate that the release of cytochrome c involves a distinct two-step process that is undermined when either step is compromised.
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Affiliation(s)
- Martin Ott
- Division of Toxicology, Institute of Environmental Medicine, Karolinska Institutet, Box 210, SE-171 77 Stockholm, Sweden
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MacLean DS, Robertson JD, Jay M. Monitoring the retention of a protein antigen in complete Freund's adjuvant, alum, and pluronic F-127 gel formulations by X-ray fluorescence. Pharm Dev Technol 2001; 6:241-6. [PMID: 11416998 DOI: 10.1081/pdt-100002200] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Adjuvants function by protecting antigens from rapid degradation or dispersal. The effectiveness of experimental adjuvants can be assessed by measuring antibody titers to the antigen of interest or, less frequently, by evaluating the retention and distribution of antigen at the application site. In this study, we used X-ray fluorescence (XRF) to monitor the release of an iodinated protein (I-bovine serum albumin) from several adjuvant formulations after its subcutaneous injection in rats. The interaction of the tagged antigen with an external Am-241 source leads to the emission of iodine X-rays from the application site; the number of these X-rays is proportional to the concentration of the protein remaining at the injection site. The disappearance of the iodine X-rays, and hence the antigen, from the injection site followed first-order kinetics for all adjuvant formulations tested; mean half-life values were as follows: in 50% Freund's adjuvant, 17.1 +/- 1.1 h; in 4-hour-old 25% Alum, 11.78 +/- 0.08 h; in 4-h-old 50% Alum, 13.2 +/- 2 h; in 3-day-old 50% Alum, 15.8 +/- 1.5 h; and in 240 mg/mL Pluronic F-127, 7.9 +/- 0.7 h. We conclude that XRF is an easy, reliable, noninvasive method to monitor the retention of antigens in these adjuvant solutions.
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Affiliation(s)
- D S MacLean
- Department of Chemistry, University of Kentucky, Lexington, KY 40506, USA
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