1
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Nguyen D, Osterlund E, Kale J, Andrews DW. The C-terminal sequences of Bcl-2 family proteins mediate interactions that regulate cell death. Biochem J 2024; 481:903-922. [PMID: 38985308 DOI: 10.1042/bcj20210352] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2024] [Revised: 06/18/2024] [Accepted: 06/19/2024] [Indexed: 07/11/2024]
Abstract
Programmed cell death via the both intrinsic and extrinsic pathways is regulated by interactions of the Bcl-2 family protein members that determine whether the cell commits to apoptosis via mitochondrial outer membrane permeabilization (MOMP). Recently the conserved C-terminal sequences (CTSs) that mediate localization of Bcl-2 family proteins to intracellular membranes, have been shown to have additional protein-protein binding functions that contribute to the functions of these proteins in regulating MOMP. Here we review the pivotal role of CTSs in Bcl-2 family interactions including: (1) homotypic interactions between the pro-apoptotic executioner proteins that cause MOMP, (2) heterotypic interactions between pro-apoptotic and anti-apoptotic proteins that prevent MOMP, and (3) heterotypic interactions between the pro-apoptotic executioner proteins and the pro-apoptotic direct activator proteins that promote MOMP.
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Affiliation(s)
- Dang Nguyen
- Department of Medical Biophysics, Faculty of Medicine, University of Toronto, Toronto, Canada
- Biological Sciences Platform, Odette Cancer Program, Sunnybrook Research Institute, Toronto, Canada
| | - Elizabeth Osterlund
- Department of Biochemistry and Biomedical Sciences, Faculty of Health Science, McMaster University, Hamilton, Canada
| | - Justin Kale
- Biological Sciences Platform, Odette Cancer Program, Sunnybrook Research Institute, Toronto, Canada
| | - David W Andrews
- Department of Medical Biophysics, Faculty of Medicine, University of Toronto, Toronto, Canada
- Biological Sciences Platform, Odette Cancer Program, Sunnybrook Research Institute, Toronto, Canada
- Department of Biochemistry, Faculty of Medicine, University of Toronto, Toronto, Canada
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2
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Gitego N, Agianian B, Mak OW, Kumar Mv V, Cheng EH, Gavathiotis E. Chemical modulation of cytosolic BAX homodimer potentiates BAX activation and apoptosis. Nat Commun 2023; 14:8381. [PMID: 38104127 PMCID: PMC10725471 DOI: 10.1038/s41467-023-44084-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Accepted: 11/29/2023] [Indexed: 12/19/2023] Open
Abstract
The BCL-2 family protein BAX is a major regulator of physiological and pathological cell death. BAX predominantly resides in the cytosol in a quiescent state and upon stress, it undergoes conformational activation and mitochondrial translocation leading to mitochondrial outer membrane permeabilization, a critical event in apoptosis execution. Previous studies reported two inactive conformations of cytosolic BAX, a monomer and a dimer, however, it remains unclear how they regulate BAX. Here we show that, surprisingly, cancer cell lines express cytosolic inactive BAX dimers and/or monomers. Expression of inactive dimers, results in reduced BAX activation, translocation and apoptosis upon pro-apoptotic drug treatments. Using the inactive BAX dimer structure and a pharmacophore-based drug screen, we identify a small-molecule modulator, BDM19 that binds and activates cytosolic BAX dimers and prompts cells to apoptosis either alone or in combination with BCL-2/BCL-XL inhibitor Navitoclax. Our findings underscore the role of the cytosolic inactive BAX dimer in resistance to apoptosis and demonstrate a strategy to potentiate BAX-mediated apoptosis.
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Affiliation(s)
- Nadege Gitego
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, NY, USA
- Department of Medicine, Albert Einstein College of Medicine, Bronx, NY, USA
- Montefiore Einstein Comprehensive Cancer Center, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Bogos Agianian
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, NY, USA
- Department of Medicine, Albert Einstein College of Medicine, Bronx, NY, USA
- Montefiore Einstein Comprehensive Cancer Center, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Oi Wei Mak
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, NY, USA
- Department of Medicine, Albert Einstein College of Medicine, Bronx, NY, USA
- Montefiore Einstein Comprehensive Cancer Center, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Vasantha Kumar Mv
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, NY, USA
- Department of Medicine, Albert Einstein College of Medicine, Bronx, NY, USA
- Montefiore Einstein Comprehensive Cancer Center, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Emily H Cheng
- Human Oncology and Pathogenesis Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA
- Department of Pathology and Laboratory Medicine, Memorial Sloan Kettering Cancer Center, New York, NY, USA
- Weill Cornell Medicine, New York, NY, USA
| | - Evripidis Gavathiotis
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, NY, USA.
- Department of Medicine, Albert Einstein College of Medicine, Bronx, NY, USA.
- Montefiore Einstein Comprehensive Cancer Center, Albert Einstein College of Medicine, Bronx, NY, USA.
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3
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Lee J, Belal SA, Lin X, Park J, Shim K. Insect Peptide CopA3 Mitigates the Effects of Heat Stress on Porcine Muscle Satellite Cells. Animals (Basel) 2023; 13:3209. [PMID: 37893933 PMCID: PMC10603636 DOI: 10.3390/ani13203209] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Revised: 10/05/2023] [Accepted: 10/12/2023] [Indexed: 10/29/2023] Open
Abstract
Heat stress inhibits cell proliferation as well as animal production. Here, we aimed to demonstrate that 9-mer disulfide dimer peptide (CopA3) supplementation stabilizes porcine muscle satellite cell (PMSC) proliferation and heat shock protein (HSP) expression at different temperatures. Therefore, we investigated the beneficial effects of CopA3 on PMSCs at three different temperatures (37, 39, and 41 °C). Based on temperature and CopA3 treatment, PMSCs were divided into six different groups including treatment and control groups for each temperature. Cell viability was highest with 10 µg/mL CopA3 and decreased as the concentration increased in a dose-dependent manner. CopA3 significantly increased the cell viability at all temperatures at 24 and 48 h. It significantly decreased apoptosis compared to that in the untreated groups. In addition, it decreased the apoptosis-related protein, Bcl-2-associated X (BAX), expression at 41 °C. Notably, temperature and CopA3 had no effects on the apoptosis-related protein, caspase 3. Expression levels of HSP40, HSP70, and HSP90 were significantly upregulated, whereas those of HSP47 and HSP60 were not affected by temperature changes. Except HSP90, CopA3 did not cause temperature-dependent changes in protein expression. Therefore, CopA3 promotes cell proliferation, inhibits apoptosis, and maintains stable HSP expression, thereby enhancing the heat-stress-tolerance capacity of PMSCs.
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Affiliation(s)
- Jeongeun Lee
- Department of Agricultural Convergence Technology, Jeonbuk National University, Jeonju 54896, Republic of Korea;
| | - Shah Ahmed Belal
- Department of Animal Biotechnology, Jeonbuk National University, Jeonju 54896, Republic of Korea;
| | - Xi Lin
- Department of Animal Science, North Carolina State University, Raleigh, NC 27695, USA;
| | - Jinryong Park
- Department of Stem Cell and Regenerative Biotechnology, Konkuk University, Seoul 05029, Republic of Korea
- 3D Tissue Culture Research Center, Konkuk University, Seoul 05029, Republic of Korea
| | - Kwanseob Shim
- Department of Agricultural Convergence Technology, Jeonbuk National University, Jeonju 54896, Republic of Korea;
- Department of Animal Biotechnology, Jeonbuk National University, Jeonju 54896, Republic of Korea;
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4
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Surien O, Masre SF, Basri DF, Ghazali AR. Potential Chemopreventive Role of Pterostilbene in Its Modulation of the Apoptosis Pathway. Int J Mol Sci 2023; 24:ijms24119707. [PMID: 37298657 DOI: 10.3390/ijms24119707] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2023] [Revised: 04/08/2023] [Accepted: 04/21/2023] [Indexed: 06/12/2023] Open
Abstract
Cancer incidence keeps increasing every year around the world and is one of the leading causes of death worldwide. Cancer has imposed a major burden on the human population, including the deterioration of physical and mental health as well as economic or financial loss among cancer patients. Conventional cancer treatments including chemotherapy, surgery, and radiotherapy have improved the mortality rate. However, conventional treatments have many challenges; for example, drug resistance, side effects, and cancer recurrence. Chemoprevention is one of the promising interventions to reduce the burden of cancer together with cancer treatments and early detection. Pterostilbene is a natural chemopreventive compound with various pharmacological properties such as anti-oxidant, anti-proliferative, and anti-inflammatory properties. Moreover, pterostilbene, due to its potential chemopreventive effect on inducing apoptosis in eliminating the mutated cells or preventing the progression of premalignant cells to cancerous cells, should be explored as a chemopreventive agent. Hence, in the review, we discuss the role of pterostilbene as a chemopreventive agent against various types of cancer via its modulation of the apoptosis pathway at the molecular levels.
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Affiliation(s)
- Omchit Surien
- Center for Toxicology and Health Risk Studies (CORE), Faculty of Health Sciences, Universiti Kebangsaan Malaysia (UKM), Kuala Lumpur 50300, Malaysia
| | - Siti Fathiah Masre
- Center for Toxicology and Health Risk Studies (CORE), Faculty of Health Sciences, Universiti Kebangsaan Malaysia (UKM), Kuala Lumpur 50300, Malaysia
| | - Dayang Fredalina Basri
- Center for Diagnostic, Therapeutic & Investigative Studies (CODTIS), Faculty of Health Sciences, Universiti Kebangsaan Malaysia (UKM), Kuala Lumpur 50300, Malaysia
| | - Ahmad Rohi Ghazali
- Center for Toxicology and Health Risk Studies (CORE), Faculty of Health Sciences, Universiti Kebangsaan Malaysia (UKM), Kuala Lumpur 50300, Malaysia
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5
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Wolf P, Schoeniger A, Edlich F. Pro-apoptotic complexes of BAX and BAK on the outer mitochondrial membrane. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2022; 1869:119317. [PMID: 35752202 DOI: 10.1016/j.bbamcr.2022.119317] [Citation(s) in RCA: 45] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Revised: 06/02/2022] [Accepted: 06/15/2022] [Indexed: 06/15/2023]
Abstract
In multicellular organisms the regulated cell death apoptosis is critically important for both ontogeny and homeostasis. Mitochondria are indispensable for stress-induced apoptosis. The BCL-2 protein family controls mitochondrial apoptosis and initiates cell death through the pro-apoptotic activities of BAX and BAK at the outer mitochondrial membrane (OMM). Cellular survival is ensured by the retrotranslocation of mitochondrial BAX and BAK into the cytosol by anti-apoptotic BCL-2 proteins. BAX/BAK-dependent OMM permeabilization releases the mitochondrial cytochrome c (cyt c), which initiates activation of caspase-9. The caspase cascade leads to cell shrinkage, plasma membrane blebbing, chromatin condensation, and apoptotic body formation. Although it is clear that ultimately complexes of active BAX and BAK commit the cell to apoptosis, the nature of these complexes is still enigmatic. Excessive research has described a range of complexes, varying from a few molecules to several 10,000, in different systems. BAX/BAK complexes potentially form ring-like structures that could expose the inner mitochondrial membrane. It has been suggested that these pores allow the efflux of small proteins and even mitochondrial DNA. Here we summarize the current state of knowledge for mitochondrial BAX/BAK complexes and the interactions between these proteins and the membrane.
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Affiliation(s)
- Philipp Wolf
- Institute of Biochemistry, Faculty of Veterinary Medicine, University of Leipzig, 04103 Leipzig, Germany
| | - Axel Schoeniger
- Institute of Biochemistry, Faculty of Veterinary Medicine, University of Leipzig, 04103 Leipzig, Germany
| | - Frank Edlich
- Institute of Biochemistry, Faculty of Veterinary Medicine, University of Leipzig, 04103 Leipzig, Germany.
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6
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Wanderoy S, Hees JT, Klesse R, Edlich F, Harbauer AB. Kill one or kill the many: interplay between mitophagy and apoptosis. Biol Chem 2020; 402:73-88. [PMID: 33544491 DOI: 10.1515/hsz-2020-0231] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Accepted: 09/22/2020] [Indexed: 12/15/2022]
Abstract
Mitochondria are key players of cellular metabolism, Ca2+ homeostasis, and apoptosis. The functionality of mitochondria is tightly regulated, and dysfunctional mitochondria are removed via mitophagy, a specialized form of autophagy that is compromised in hereditary forms of Parkinson's disease. Through mitophagy, cells are able to cope with mitochondrial stress until the damage becomes too great, which leads to the activation of pro-apoptotic BCL-2 family proteins located on the outer mitochondrial membrane. Active pro-apoptotic BCL-2 proteins facilitate the release of cytochrome c from the mitochondrial intermembrane space (IMS) into the cytosol, committing the cell to apoptosis by activating a cascade of cysteinyl-aspartate specific proteases (caspases). We are only beginning to understand how the choice between mitophagy and the activation of caspases is determined on the mitochondrial surface. Intriguingly in neurons, caspase activation also plays a non-apoptotic role in synaptic plasticity. Here we review the current knowledge on the interplay between mitophagy and caspase activation with a special focus on the central nervous system.
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Affiliation(s)
- Simone Wanderoy
- Max Planck Institute for Neurobiology, Am Klopferspitz 18, D-82152Martinsried, Germany
| | - J Tabitha Hees
- Max Planck Institute for Neurobiology, Am Klopferspitz 18, D-82152Martinsried, Germany
| | - Ramona Klesse
- Institute for Biochemistry and Molecular Biology, University of Freiburg, D-79104Freiburg, Germany.,Faculty of Biology, University of Freiburg, D-79104Freiburg, Germany
| | - Frank Edlich
- Institute for Biochemistry and Molecular Biology, University of Freiburg, D-79104Freiburg, Germany
| | - Angelika B Harbauer
- Max Planck Institute for Neurobiology, Am Klopferspitz 18, D-82152Martinsried, Germany.,Technical University of Munich, Institute of Neuronal Cell Biology, Munich, Germany.,Munich Cluster for Systems Neurology, Munich, Germany
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7
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Peintner L, Venkatraman A, Waeldin A, Hofherr A, Busch T, Voronov A, Viau A, Kuehn EW, Köttgen M, Borner C. Loss of PKD1/polycystin-1 impairs lysosomal activity in a CAPN (calpain)-dependent manner. Autophagy 2020; 17:2384-2400. [PMID: 32967521 DOI: 10.1080/15548627.2020.1826716] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Mutations in the PKD1 gene result in autosomal dominant polycystic kidney disease (ADPKD), the most common monogenetic cause of end-stage renal disease (ESRD) in humans. Previous reports suggested that PKD1, together with PKD2/polycystin-2, may function as a receptor-cation channel complex at cilia and on intracellular membranes and participate in various signaling pathways to regulate cell survival, proliferation and macroautophagy/autophagy. However, the exact molecular function of PKD1 and PKD2 has remained enigmatic. Here we used Pkd1-deficient mouse inner medullary collecting duct cells (mIMCD3) genetically deleted for Pkd1, and tubular epithelial cells isolated from nephrons of doxycycline-inducible conditional pkd1fl/fl;Pax8rtTA;TetOCre+ knockout mice to show that the lack of Pkd1 caused diminished lysosomal acidification, LAMP degradation and reduced CTSB/cathepsin B processing and activity. This led to an impairment of autophagosomal-lysosomal fusion, a lower delivery of ubiquitinated cargo from multivesicular bodies (MVB)/exosomes to lysosomes and an enhanced secretion of unprocessed CTSB into the extracellular space. The TFEB-dependent lysosomal biogenesis pathway was however unaffected. Pkd1-deficient cells exhibited increased activity of the calcium-dependent CAPN (calpain) proteases, probably due to a higher calcium influx. Consistent with this notion CAPN inhibitors restored lysosomal function, CTSB processing/activity and autophagosomal-lysosomal fusion, and blocked CTSB secretion and LAMP degradation in pkd1 knockout cells. Our data reveal for the first time a lysosomal function of PKD1 which keeps CAPN activity in check and ensures lysosomal integrity and a correct autophagic flux.Abbreviations: acCal: acetyl-calpastatin peptide; ADPKD: autosomal dominant polycystic kidney disease; CI-1: calpain inhibitor-1; CQ: chloroquine; Dox: doxycycline; EV: extracellular vesicles; EXO: exosomes; LAMP1/2: lysosomal-associated membrane protein 1/2; LGALS1/GAL1/galectin-1: lectin, galactose binding, soluble 1; LMP: lysosomal membrane permeabilization; mIMCD3: mouse inner medullary collecting duct cells; MV: microvesicles; MVB: multivesicular bodies; PAX8: paired box 8; PKD1/polycystin-1: polycystin 1, transient receptor potential channel interacting; PKD2/polycystin-2: polycystin 2, transient receptor potential cation channel; Tet: tetracycline; TFEB: transcription factor EB; VFM: vesicle-free medium; WT: wild-type.
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Affiliation(s)
- Lukas Peintner
- Institute of Molecular Medicine and Cell Research, Faculty of Medicine, Albert Ludwigs University of Freiburg, Freiburg, Germany
| | - Anusha Venkatraman
- Institute of Molecular Medicine and Cell Research, Faculty of Medicine, Albert Ludwigs University of Freiburg, Freiburg, Germany.,Spemann Graduate School of Biology and Medicine, Albert Ludwigs University of Freiburg, Freiburg, Germany.,Albert Ludwigs University of Freiburg, Faculty of Biology, Freiburg, Germany
| | - Astrid Waeldin
- Institute of Molecular Medicine and Cell Research, Faculty of Medicine, Albert Ludwigs University of Freiburg, Freiburg, Germany
| | - Alexis Hofherr
- Renal Division, Department of Medicine, Medical Center, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Tilman Busch
- Renal Division, Department of Medicine, Medical Center, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Alexander Voronov
- Institute of Molecular Medicine and Cell Research, Faculty of Medicine, Albert Ludwigs University of Freiburg, Freiburg, Germany
| | - Amandine Viau
- Renal Division, Department of Medicine, Medical Center, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - E Wolfgang Kuehn
- Renal Division, Department of Medicine, Medical Center, Faculty of Medicine, University of Freiburg, Freiburg, Germany.,Center for Integrative Biological Signalling Studies (CIBSS), Albert Ludwigs University of Freiburg, Freiburg, Germany
| | - Michael Köttgen
- Spemann Graduate School of Biology and Medicine, Albert Ludwigs University of Freiburg, Freiburg, Germany.,Renal Division, Department of Medicine, Medical Center, Faculty of Medicine, University of Freiburg, Freiburg, Germany.,Center for Integrative Biological Signalling Studies (CIBSS), Albert Ludwigs University of Freiburg, Freiburg, Germany
| | - Christoph Borner
- Institute of Molecular Medicine and Cell Research, Faculty of Medicine, Albert Ludwigs University of Freiburg, Freiburg, Germany.,Spemann Graduate School of Biology and Medicine, Albert Ludwigs University of Freiburg, Freiburg, Germany.,Center for Biological Signalling Studies (BIOSS), Albert Ludwigs University of Freiburg, Freiburg, Germany
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8
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Fitzsimmons L, Cartlidge R, Chang C, Sejic N, Galbraith LCA, Suraweera CD, Croom-Carter D, Dewson G, Tierney RJ, Bell AI, Shannon-Lowe C, Herold MJ, Rickinson AB, Colman PM, Huang DCS, Strasser A, Kvansakul M, Rowe M, Kelly GL. EBV BCL-2 homologue BHRF1 drives chemoresistance and lymphomagenesis by inhibiting multiple cellular pro-apoptotic proteins. Cell Death Differ 2020; 27:1554-1568. [PMID: 31645677 PMCID: PMC7206097 DOI: 10.1038/s41418-019-0435-1] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2019] [Revised: 10/01/2019] [Accepted: 10/07/2019] [Indexed: 12/30/2022] Open
Abstract
Epstein-Barr virus (EBV), which is ubiquitous in the adult population, is causally associated with human malignancies. Like many infectious agents, EBV has evolved strategies to block host cell death, including through expression of viral homologues of cellular BCL-2 pro-survival proteins (vBCL-2s), such as BHRF1. Small molecule inhibitors of the cellular pro-survival BCL-2 family proteins, termed 'BH3-mimetics', have entered clinical trials for blood cancers with the BCL-2 inhibitor venetoclax already approved for treatment of therapy refractory chronic lymphocytic leukaemia and acute myeloid leukaemia in the elderly. The generation of BH3-mimetics that could specifically target vBCL-2 proteins may be an attractive therapeutic option for virus-associated cancers, since these drugs would be expected to only kill virally infected cells with only minimal side effects on normal healthy tissues. To achieve this, a better understanding of the contribution of vBCL-2 proteins to tumorigenesis and insights into their biochemical functions is needed. In the context of Burkitt lymphoma (BL), BHRF1 expression conferred strong resistance to diverse apoptotic stimuli. Furthermore, BHRF1 expression in mouse haematopoietic stem and progenitor cells accelerated MYC-induced lymphoma development in a model of BL. BHRF1 interacts with the cellular pro-apoptotic BCL-2 proteins, BIM, BID, PUMA and BAK, but its capability to inhibit apoptosis could not be mapped solely to one of these interactions, suggesting plasticity is a key feature of BHRF1. Site-directed mutagenesis revealed a site in BHRF1 that was critical for its interaction with PUMA and blocking DNA-damage-induced apoptosis, identifying a potentially therapeutically targetable vulnerability in BHRF1.
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Affiliation(s)
- Leah Fitzsimmons
- Institute of Cancer and Genomic Sciences, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK.
| | - Rachel Cartlidge
- Institute of Cancer and Genomic Sciences, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Catherine Chang
- The Walter and Eliza Hall Institute for Medical Research, Parkville, Melbourne, VIC, 3052, Australia
| | - Nenad Sejic
- The Walter and Eliza Hall Institute for Medical Research, Parkville, Melbourne, VIC, 3052, Australia
- Department of Medical Biology, The University of Melbourne, Parkville, Melbourne, VIC, 3052, Australia
- Institute of Immunology and Immunotherapy, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Laura C A Galbraith
- Cancer Research UK Beatson Institute, Glasgow, G61 1BD, UK
- Institute of Cancer Sciences, University of Glasgow, Glasgow, G61 1QH, UK
| | - Chathura D Suraweera
- La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC, 3086, Australia
| | - Deborah Croom-Carter
- Institute of Cancer and Genomic Sciences, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Grant Dewson
- The Walter and Eliza Hall Institute for Medical Research, Parkville, Melbourne, VIC, 3052, Australia
- Department of Medical Biology, The University of Melbourne, Parkville, Melbourne, VIC, 3052, Australia
| | - Rosemary J Tierney
- Institute of Cancer and Genomic Sciences, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Andrew I Bell
- Institute of Immunology and Immunotherapy, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Clare Shannon-Lowe
- Institute of Immunology and Immunotherapy, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Marco J Herold
- The Walter and Eliza Hall Institute for Medical Research, Parkville, Melbourne, VIC, 3052, Australia
- Department of Medical Biology, The University of Melbourne, Parkville, Melbourne, VIC, 3052, Australia
| | - Alan B Rickinson
- Institute of Cancer and Genomic Sciences, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Peter M Colman
- The Walter and Eliza Hall Institute for Medical Research, Parkville, Melbourne, VIC, 3052, Australia
- Department of Medical Biology, The University of Melbourne, Parkville, Melbourne, VIC, 3052, Australia
| | - David C S Huang
- The Walter and Eliza Hall Institute for Medical Research, Parkville, Melbourne, VIC, 3052, Australia
- Department of Medical Biology, The University of Melbourne, Parkville, Melbourne, VIC, 3052, Australia
| | - Andreas Strasser
- The Walter and Eliza Hall Institute for Medical Research, Parkville, Melbourne, VIC, 3052, Australia
- Department of Medical Biology, The University of Melbourne, Parkville, Melbourne, VIC, 3052, Australia
| | - Marc Kvansakul
- La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC, 3086, Australia
| | - Martin Rowe
- Institute of Cancer and Genomic Sciences, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Gemma L Kelly
- The Walter and Eliza Hall Institute for Medical Research, Parkville, Melbourne, VIC, 3052, Australia.
- Department of Medical Biology, The University of Melbourne, Parkville, Melbourne, VIC, 3052, Australia.
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9
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Edlich F. BCL-2 proteins and apoptosis: Recent insights and unknowns. Biochem Biophys Res Commun 2018; 500:26-34. [DOI: 10.1016/j.bbrc.2017.06.190] [Citation(s) in RCA: 233] [Impact Index Per Article: 38.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2017] [Accepted: 06/30/2017] [Indexed: 01/08/2023]
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10
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Sereno D, Müller WE, Bausen M, Elkhooly TA, Markl JS, Wiens M. An evolutionary perspective on the role of mesencephalic astrocyte-derived neurotrophic factor (MANF): At the crossroads of poriferan innate immune and apoptotic pathways. Biochem Biophys Rep 2017; 11:161-173. [PMID: 28955781 PMCID: PMC5614693 DOI: 10.1016/j.bbrep.2017.02.009] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Revised: 02/17/2017] [Accepted: 02/27/2017] [Indexed: 11/30/2022] Open
Abstract
The mesencephalic astrocyte-derived neurotrophic factor (MANF) belongs to a recently discovered family of neurotrophic factors. MANF can be secreted but is generally resident within the endoplasmic reticulum (ER) in neuronal and non-neuronal cells, where it is involved in the ER stress response with pro-survival effects. Here we report the discovery of the MANF homolog SDMANF in the sponge Suberites domuncula. The basal positioning of sponges (phylum Porifera) in the animal tree of life offers a unique vantage point on the early evolution of the metazoan-specific genetic toolkit and molecular pathways. Since sponges lack a conventional nervous system, SDMANF presents an enticing opportunity to investigate the evolutionary ancient role of these neurotrophic factors. SDMANF shares considerable sequence similarity with its metazoan homologs. It also comprises a putative protein binding domain with sequence similarities to the Bcl-2 family of apoptotic regulators. In Suberites, SDMANF is expressed in the vicinity of bacteriocytes, where it co-localizes with the toll-like receptor SDTLR. In transfected human cells, SDMANF was detected in both the organelle protein fraction and the cell culture medium. The intracellular SDMANF protein level was up-regulated in response to both a Golgi/ER transport inhibitor and bacterial lipopolysaccharides (LPS). Upon LPS challenge, transfected cells revealed a decreased caspase-3 activity and increased cell viability with no inducible Bax expression compared to the wild type. These results suggest a deep evolutionary original cytoprotective role of MANF, at the crossroads of innate immune and apoptotic pathways, of which a neurotrophic function might have arisen later in metazoan evolution.
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Affiliation(s)
| | | | | | | | | | - Matthias Wiens
- Institute for Physiological Chemistry, University Medical Center, Johannes Gutenberg-University, Duesbergweg 6, D-55128 Mainz, Germany
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11
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Cakir Z, Funk K, Lauterwasser J, Todt F, Zerbes RM, Oelgeklaus A, Tanaka A, van der Laan M, Edlich F. Parkin promotes proteasomal degradation of misregulated BAX. J Cell Sci 2017; 130:2903-2913. [DOI: 10.1242/jcs.200162] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Accepted: 07/21/2017] [Indexed: 12/23/2022] Open
Abstract
The pro-apoptotic BCL-2 protein BAX commits human cells to apoptosis by permeabilizing the outer mitochondrial membrane. BAX activation has been suggested to require the separation of helix α5 from α6 and thus the ‘latch’ from the ‘core’ domain among other conformational changes. Here we show that conformational changes in this region impair BAX translocation to the mitochondria and retrotranslocation back into the cytosol and therefore BAX inhibition, but not activation. Redirecting misregulated BAX to the mitochondria revealed an alternative mechanism of BAX inhibition. The E3 ligase Parkin, known to trigger mitochondria-specific autophagy, ubiquitinates BAX K128 and targets the pro-apoptotic BCL-2 protein for proteasomal degradation. Retrotranslocation-deficient BAX is completely degraded in a Parkin-dependent manner. Although only a minor pool of endogenous BAX escapes retrotranslocation into the cytosol, Parkin-dependent targeting of misregulated BAX on the mitochondria provides substantial protection against BAX apoptotic activity.
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Affiliation(s)
- Zeynep Cakir
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany
- Faculty of Biology, University of Freiburg, 79104 Freiburg, Germany
| | - Kathrin Funk
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany
- Faculty of Biology, University of Freiburg, 79104 Freiburg, Germany
| | - Joachim Lauterwasser
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany
- Faculty of Biology, University of Freiburg, 79104 Freiburg, Germany
| | - Franziska Todt
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany
| | - Ralf M. Zerbes
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany
- Faculty of Biology, University of Freiburg, 79104 Freiburg, Germany
| | - Aline Oelgeklaus
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany
- Faculty of Biology, University of Freiburg, 79104 Freiburg, Germany
- Spemann Graduate School of Biology and Medicine, SGBM, 79104 Freiburg, Germany
| | - Atsushi Tanaka
- Research Institute of Medical Sciences, Yamagata University School of Medicine, 990-9585 Yamagata, Japan
| | - Martin van der Laan
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany
- Medical Biochemistry and Molecular Biology, Saarland University, D-66421 Homburg, Germany
- BIOSS, Centre for Biological Signaling Studies, University of Freiburg, 79104 Freiburg, Germany
| | - Frank Edlich
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany
- BIOSS, Centre for Biological Signaling Studies, University of Freiburg, 79104 Freiburg, Germany
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12
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Maurya SR, Mahalakshmi R. Mitochondrial VDAC2 and cell homeostasis: highlighting hidden structural features and unique functionalities. Biol Rev Camb Philos Soc 2016; 92:1843-1858. [PMID: 28980434 DOI: 10.1111/brv.12311] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2016] [Revised: 10/04/2016] [Accepted: 10/11/2016] [Indexed: 02/06/2023]
Abstract
Voltage-dependent anion channels (VDACs) are the gateway to mitochondrial processes, interlinking the cytosolic and mitochondrial compartments. The mitochondrion acts as a storehouse for cytochrome c, the effector of apoptosis, and hence VDACs become intricately involved in the apoptotic pathway. Isoform 1 of VDAC is abundant in the outer mitochondrial membrane of many cell types, while isoform 2 is the preferred channel in specialized cells including brain and some cancer cells. The primary role of VDACs is metabolite flux. The pro- and anti-apoptotic role of VDAC1 and VDAC2, respectively, are secondary, and are influenced by external factors and interacting proteins. Herein, we focus on the less-studied VDAC2, and shed light on its unique functions and features. VDAC2, along with sharing many of its functions with VDAC1, such as metabolite and Ca2+ transport, also has many delineating functions. VDAC2 is closely engaged in the gametogenesis and steroidogenesis pathways and in protection from oxidative stress as well as in neurodegenerative diseases like Alzheimer's and epilepsy. A closer examination of the functional pathways of VDACs indicates that the unique functions of VDAC2 are a result of the different interactome of this isoform. We couple functional differences to the structural and biophysical evidence obtained for the VDACs, and present a testament of why the two VDAC isoforms with >90% sequence similarity, are functionally diverse. Based on these differences, we suggest that the VDAC isoforms now be considered as paralogs. An in-depth understanding of VDAC2 will help us to design better biomolecule targets for cancer and neurodegenerative diseases.
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Affiliation(s)
- Svetlana Rajkumar Maurya
- Molecular Biophysics Laboratory, Department of Biological Sciences, Indian Institute of Science Education and Research, Bhopal, 462066, India
| | - Radhakrishnan Mahalakshmi
- Molecular Biophysics Laboratory, Department of Biological Sciences, Indian Institute of Science Education and Research, Bhopal, 462066, India
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13
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The porin VDAC2 is the mitochondrial platform for Bax retrotranslocation. Sci Rep 2016; 6:32994. [PMID: 27620692 PMCID: PMC5020405 DOI: 10.1038/srep32994] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2016] [Accepted: 08/18/2016] [Indexed: 12/25/2022] Open
Abstract
The pro-apoptotic Bcl-2 protein Bax can permeabilize the outer mitochondrial membrane and therefore commit human cells to apoptosis. Bax is regulated by constant translocation to the mitochondria and retrotranslocation back into the cytosol. Bax retrotranslocation depends on pro-survival Bcl-2 proteins and stabilizes inactive Bax. Here we show that Bax retrotranslocation shuttles membrane-associated and membrane-integral Bax from isolated mitochondria. We further discover the mitochondrial porin voltage-dependent anion channel 2 (VDAC2) as essential component and platform for Bax retrotranslocation. VDAC2 ensures mitochondria-specific membrane association of Bax and in the absence of VDAC2 Bax localizes towards other cell compartments. Bax retrotranslocation is also regulated by nucleotides and calcium ions, suggesting a potential role of the transport of these ions through VDAC2 in Bax retrotranslocation. Together, our results reveal the unanticipated bifunctional role of VDAC2 to target Bax specifically to the mitochondria and ensure Bax inhibition by retrotranslocation into the cytosol.
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14
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Garner TP, Reyna DE, Priyadarshi A, Chen HC, Li S, Wu Y, Ganesan YT, Malashkevich VN, Cheng EH, Gavathiotis E. An Autoinhibited Dimeric Form of BAX Regulates the BAX Activation Pathway. Mol Cell 2016; 63:485-97. [PMID: 27425408 PMCID: PMC4975667 DOI: 10.1016/j.molcel.2016.06.010] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2015] [Revised: 04/22/2016] [Accepted: 05/06/2016] [Indexed: 12/21/2022]
Abstract
Pro-apoptotic BAX is a cell fate regulator playing an important role in cellular homeostasis and pathological cell death. BAX is predominantly localized in the cytosol, where it has a quiescent monomer conformation. Following a pro-apoptotic trigger, cytosolic BAX is activated and translocates to the mitochondria to initiate mitochondrial dysfunction and apoptosis. Here, cellular, biochemical, and structural data unexpectedly demonstrate that cytosolic BAX also has an inactive dimer conformation that regulates its activation. The full-length crystal structure of the inactive BAX dimer revealed an asymmetric interaction consistent with inhibition of the N-terminal conformational change of one protomer and the displacement of the C-terminal helix α9 of the second protomer. This autoinhibited BAX dimer dissociates to BAX monomers before BAX can be activated. Our data support a model whereby the degree of apoptosis induction is regulated by the conformation of cytosolic BAX and identify an unprecedented mechanism of cytosolic BAX inhibition.
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Affiliation(s)
- Thomas P Garner
- Department of Biochemistry and Department of Medicine, Albert Einstein Cancer Center, Wilf Family Cardiovascular Research Institute, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Denis E Reyna
- Department of Biochemistry and Department of Medicine, Albert Einstein Cancer Center, Wilf Family Cardiovascular Research Institute, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Amit Priyadarshi
- Department of Biochemistry and Department of Medicine, Albert Einstein Cancer Center, Wilf Family Cardiovascular Research Institute, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Hui-Chen Chen
- Human Oncology and Pathogenesis Program and Department of Pathology, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Sheng Li
- Department of Medicine and UCSD DXMS Proteomics Resource, University of California, San Diego, La Jolla, CA 92093, USA
| | - Yang Wu
- Department of Biochemistry and Department of Medicine, Albert Einstein Cancer Center, Wilf Family Cardiovascular Research Institute, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Yogesh Tengarai Ganesan
- Human Oncology and Pathogenesis Program and Department of Pathology, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Vladimir N Malashkevich
- Department of Biochemistry and Department of Biophysics and Physiology, Albert Einstein Cancer Center, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Emily H Cheng
- Human Oncology and Pathogenesis Program and Department of Pathology, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Evripidis Gavathiotis
- Department of Biochemistry and Department of Medicine, Albert Einstein Cancer Center, Wilf Family Cardiovascular Research Institute, Albert Einstein College of Medicine, Bronx, NY 10461, USA.
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15
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Hada M, Subramanian C, Andrews PC, Kwok RPS. Cytosolic Ku70 regulates Bax-mediated cell death. Tumour Biol 2016; 37:13903-13914. [PMID: 27488115 PMCID: PMC5097087 DOI: 10.1007/s13277-016-5202-z] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2016] [Accepted: 07/13/2016] [Indexed: 11/29/2022] Open
Abstract
The first known function of Ku70 is as a DNA repair factor in the nucleus. Using neuronal neuroblastoma cells as a model, we have established that cytosolic Ku70 binds to the pro-apoptotic protein Bax in the cytosol and blocks Bax’s cell death activity. Ku70-Bax binding is regulated by Ku70 acetylation in that when Ku70 is acetylated Bax dissociates from Ku70, triggering cell death. We propose that Ku70 may act as a survival factor in these cells such that Ku70 depletion triggers Bax-dependent cell death. Here, we addressed two fundamental questions about this model: (1) Does all Bax, which is a cytosolic protein, bind to all cytosolic Ku70? and (2) Is Ku70 a survival factor in cells types other than neuronal neuroblastoma cells? We show here that, in neuronal neuroblastoma cells, only a small fraction of Ku70 binds to a small fraction of Bax; most Bax is monomeric. Interestingly, there is no free or monomeric Ku70 in the cytosol; most cytosolic Ku70 is in complex with other factors forming several high molecular weight complexes. A fraction of cytosolic Ku70 also binds to cytosolic Ku80, Ku70’s binding partner in the nucleus. Ku70 may not be a survival factor in some cell types (Ku70-depletion less sensitive) because Ku70 depletion does not affect survival of these cells. These results indicate that, in addition to Ku70 acetylation, other factors may be involved in regulating Ku70-Bax binding in the Ku70-depletion less sensitive cells because Ku70 acetylation in these cells is not sufficient to dissociate Bax from Ku70 or to activate Bax.
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Affiliation(s)
- Manila Hada
- Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Chitra Subramanian
- General Surgery, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Phillip C Andrews
- Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Roland P S Kwok
- Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, MI, USA. .,Obstetrics and Gynecology, University of Michigan Medical School, 1150 West Medical Center Drive, Ann Arbor, MI, 48109, USA.
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16
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Chang CZ, Wu SC, Kwan AL, Lin CL. Preconditioning with pitavastatin, an HMG-CoA reductase inhibitor, attenuates C-Jun N-terminal kinase activation in experimental subarachnoid hemorrhage-induced apoptosis. Acta Neurochir (Wien) 2015; 157:1031-41; discussion 1041. [PMID: 25894080 DOI: 10.1007/s00701-015-2399-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2014] [Accepted: 03/10/2015] [Indexed: 01/27/2023]
Abstract
BACKGROUND Accumulating results have disclosed that early brain injury (EBI) may play a major role in the determination of the outcome of aneurysmal subarachnoid hemorrhage (SAH) patients. This study is of interest to examine the efficacy of pitavastatin, a 3-hydroxy-3-methyl-glutaryl-CoA reductase (HMG-CoA reductase) inhibitor, on SAH-induced apoptosis. METHODS A rodent double SAH model was employed. Pitavastatin was administered orally. CSF IL-1β, IL-6, IL-8 and TNF-α were measured (rt-PCR). Basilar arteries were harvested for C-Jun N-terminal kinase p46/p55 (cJNK (p46/p55)), matrix metallopeptidase-9 (MMP-9) (Western blot), caspase and Bcl-2 (rt-PCR) evaluation. RESULTS Pitavastatin reduced the bioexpression of cJNK p55 compared with the SAH groups. Cleaved caspase-9a was significantly reduced in the pitavastatin-preconditioned group compared with the SAH group (p > 0.05). IL-1β and TNF-α levels were reduced in the pitavastatin-preconditioned group. Pretreatment with pitavastatin significantly reduced activated MMP-9, capsase-9a and B-cell lymphoma 2(Bcl) mRNA. CONCLUSION Preconditioning with pitavastatin exerts its neuroprotective effect through the dual action of inhibiting cJNK(p46/p55) activation and reducing cleaved caspase-9a expression. Besides, the bioinhibition of MMP-9 may partially contribute to the neuroprotective effect. This study lends credence to the theory that statins, especially in the preconditioning status, may attenuate SAH-induced neuron apoptosis.
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Affiliation(s)
- Chih-Zen Chang
- Department of Surgery, Faculty of Medicine, School of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan,
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17
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Dewson G. Detection of Bak/Bax activating conformation change by intracellular flow cytometry. Cold Spring Harb Protoc 2015; 2015:477-80. [PMID: 25934938 DOI: 10.1101/pdb.prot086462] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Like the commonly used immunoprecipitation (IP) approach, this procedure for the detection of activated Bak or Bax by intracellular flow cytometry is based on the principle that Bak and Bax, during activation, expose occluded amino-terminal epitopes that can be recognized by conformation-specific antibodies. Flow cytometric analysis requires fewer cells and is less time-consuming than IP. Further, in contrast to IP, flow cytometry produces a quantifiable assessment of the percentage of cells containing activated Bak or Bax, which can be correlated with cell death.
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Affiliation(s)
- Grant Dewson
- Cell Signalling and Cell Death Division, Walter and Eliza Hall Institute of Medical Research, Parkville, Melbourne, Victoria 3052, Australia;Department of Medical Biology, The University of Melbourne, Melbourne, Victoria 3010, Australia
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18
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Dewson G. Investigating Bak/Bax activating conformation change by immunoprecipitation. Cold Spring Harb Protoc 2015; 2015:472-6. [PMID: 25934937 DOI: 10.1101/pdb.prot086454] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Activation of both Bax and Bak during apoptosis involves significant conformation change. Investigation of this phenomenon by immunoprecipitation (IP) requires a detergent such as CHAPS that does not induce significant conformation change. IP with conformation-specific Bax or Bak antibodies is observed in CHAPS only following an apoptotic stimulus, whereas the same antibodies will immunoprecipitate from both nonapoptotic and apoptotic cells in the presence of Triton X-100. Thus, the latter detergent can serve as a positive control for IP, as described here.
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Affiliation(s)
- Grant Dewson
- Cell Signalling and Cell Death Division, Walter and Eliza Hall Institute of Medical Research, Parkville, Melbourne, Victoria 3052, Australia;Department of Medical Biology, The University of Melbourne, Melbourne, Victoria 3010, Australia
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19
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The apoptotic pore on mitochondria: are we breaking through or still stuck? Cell Death Differ 2015; 21:187-91. [PMID: 24413197 DOI: 10.1038/cdd.2013.169] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
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20
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Gahl RF, He Y, Yu S, Tjandra N. Conformational rearrangements in the pro-apoptotic protein, Bax, as it inserts into mitochondria: a cellular death switch. J Biol Chem 2014; 289:32871-82. [PMID: 25315775 DOI: 10.1074/jbc.m114.593897] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The B-cell lymphoma 2 (Bcl-2) family of proteins regulates the activation of apoptosis through the mitochondria pathway. Pro- and anti-apoptotic members of this family keep each other in check until the correct time to commit to apoptosis. The point of no return for this commitment is the permeabilization of the outer mitochondrial membrane. Translocation of the pro-apoptotic member, Bax, from the cytosol to the mitochondria is the molecular signature of this event. We employed a novel method to reliably detect Förster resonance energy transfer (FRET) between pairs of fluorophores to identify intra-molecular conformational changes and inter-molecular contacts in Bax as this translocation occurs in live cells. In the cytosol, our FRET measurement indicated that the C-terminal helix is exposed instead of tucked away in the core of the protein. In addition fluorescence correlation spectroscopy (FCS) showed that cytosolic Bax diffuses much slower than expected, suggesting possible complex formation or transient membrane interaction. Cross-linking the C-terminal helix (α9) to helix α4 reduced the potential of those interactions to occur. After translocation, our FRET measurements showed that Bax molecules form homo-oligomers in the mitochondria through two distinct interfaces involving the BH3 domain (helix α2) and the C-terminal helix. These findings have implications for possible contacts with other Bcl-2 proteins necessary for the regulation of apoptosis.
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Affiliation(s)
- Robert F Gahl
- From the Laboratory of Molecular Biophysics, Biochemistry and Biophysics Center, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland 20892
| | - Yi He
- From the Laboratory of Molecular Biophysics, Biochemistry and Biophysics Center, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland 20892
| | - Shiqin Yu
- From the Laboratory of Molecular Biophysics, Biochemistry and Biophysics Center, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland 20892
| | - Nico Tjandra
- From the Laboratory of Molecular Biophysics, Biochemistry and Biophysics Center, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland 20892
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21
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Activation of histamine H4 receptor inhibits TNFα/IMD-0354-induced apoptosis in human salivary NS-SV-AC cells. Apoptosis 2014; 19:1702-11. [DOI: 10.1007/s10495-014-1036-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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22
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Chi X, Kale J, Leber B, Andrews DW. Regulating cell death at, on, and in membranes. BIOCHIMICA ET BIOPHYSICA ACTA 2014; 1843:2100-13. [PMID: 24927885 DOI: 10.1016/j.bbamcr.2014.06.002] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2014] [Revised: 05/29/2014] [Accepted: 06/03/2014] [Indexed: 11/17/2022]
Abstract
Bcl-2 family proteins are central regulators of apoptosis. Various family members are located in the cytoplasm, endoplasmic reticulum, and mitochondrial outer membrane in healthy cells. However during apoptosis most of the interactions between family members that determine the fate of the cell occur at the membranes of intracellular organelles. It has become evident that interactions with membranes play an active role in the regulation of Bcl-2 family protein interactions. Here we provide an overview of various models proposed to explain how the Bcl-2 family regulates apoptosis and discuss how membrane binding affects the structure and function of each of the three categories of Bcl-2 proteins (pro-apoptotic, pore-forming, and anti-apoptotic). We also examine how the Bcl-2 family regulates other aspects of mitochondrial and ER physiology relevant to cell death.
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Affiliation(s)
- Xiaoke Chi
- Department of Chemistry and Chemical Biology, McMaster University, Hamilton, Ontario L8N 3Z5, Canada
| | - Justin Kale
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario L8N 3Z5, Canada
| | - Brian Leber
- Department of Medicine, McMaster University, Hamilton, Ontario L8N 3Z5, Canada
| | - David W Andrews
- Department of Chemistry and Chemical Biology, McMaster University, Hamilton, Ontario L8N 3Z5, Canada; Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario L8N 3Z5, Canada; Biological Sciences, Sunnybrook Research Institute, Toronto, Ontario M4N 3M5, Canada; Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada.
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23
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Bax targets mitochondria by distinct mechanisms before or during apoptotic cell death: a requirement for VDAC2 or Bak for efficient Bax apoptotic function. Cell Death Differ 2014; 21:1925-35. [PMID: 25146925 DOI: 10.1038/cdd.2014.119] [Citation(s) in RCA: 92] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2014] [Revised: 06/24/2014] [Accepted: 07/13/2014] [Indexed: 01/15/2023] Open
Abstract
In non-apoptotic cells, Bak constitutively resides in the mitochondrial outer membrane. In contrast, Bax is in a dynamic equilibrium between the cytosol and mitochondria, and is commonly predominant in the cytosol. In response to an apoptotic stimulus, Bax and Bak change conformation, leading to Bax accumulation at mitochondria and Bak/Bax oligomerization to form a pore in the mitochondrial outer membrane that is responsible for cell death. Using blue native-PAGE to investigate how Bax oligomerizes in the mitochondrial outer membrane, we observed that, like Bak, a proportion of Bax that constitutively resides at mitochondria associates with voltage-dependent anion channel (VDAC)2 prior to an apoptotic stimulus. During apoptosis, Bax dissociates from VDAC2 and homo-oligomerizes to form high molecular weight oligomers. In cells that lack VDAC2, constitutive mitochondrial localization of Bax and Bak was impaired, suggesting that VDAC2 has a role in Bax and Bak import to, or stability at, the mitochondrial outer membrane. However, following an apoptotic stimulus, Bak and Bax retained the ability to accumulate at VDAC2-deficient mitochondria and to mediate cell death. Silencing of Bak in VDAC2-deficient cells indicated that Bax required either VDAC2 or Bak in order to translocate to and oligomerize at the mitochondrial outer membrane to efficiently mediate apoptosis. In contrast, efficient Bak homo-oligomerization at the mitochondrial outer membrane and its pro-apoptotic function required neither VDAC2 nor Bax. Even a C-terminal mutant of Bax (S184L) that localizes to mitochondria did not constitutively target mitochondria deficient in VDAC2, but was recruited to mitochondria following an apoptotic stimulus dependent on Bak or upon over-expression of Bcl-xL. Together, our data suggest that Bax localizes to the mitochondrial outer membrane via alternate mechanisms, either constitutively via an interaction with VDAC2 or after activation via interaction with Bcl-2 family proteins.
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24
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Simonishvili S, Jain M, Li H, Levison S, Wood T. Identification of Bax-interacting proteins in oligodendrocyte progenitors during glutamate excitotoxicity and perinatal hypoxia-ischemia. ASN Neuro 2013; 5:e00131. [PMID: 24195677 PMCID: PMC3891358 DOI: 10.1042/an20130027] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
OPC (oligodendrocyte progenitor cell) death contributes significantly to the pathology and functional deficits following hypoxic-ischemic injury in the immature brain and to deficits resulting from demyelinating diseases, trauma and degenerative disorders in the adult CNS. Glutamate toxicity is a major cause of oligodendroglial death in diverse CNS disorders, and previous studies have demonstrated that AMPA/kainate receptors require the pro-apoptotic protein Bax in OPCs undergoing apoptosis. The goal of the present study was to define the pro-apoptotic and anti-apoptotic effectors that regulate Bax in healthy OPCs and after exposure to excess glutamate in vitro and following H-I (hypoxia-ischemia) in the immature rat brain. We show that Bax associates with a truncated form of Bid, a BH3-only domain protein, subsequent to glutamate treatment. Furthermore, glutamate exposure reduces Bax association with the anti-apoptotic Bcl family member, Bcl-xL. Cell fractionation studies demonstrated that both Bax and Bid translocate from the cytoplasm to mitochondria during the early stages of cell death consistent with a role for Bid as an activator, whereas Bcl-xL, which normally complexes with both Bax and Bid, disassociates from these complexes when OPCs are exposed to excess glutamate. Bax remained unactivated in the presence of insulin-like growth factor-1, and the Bcl-xL complexes were protected. Our data similarly demonstrate loss of Bcl-xL-Bax association in white matter following H-I and implicate active Bad in Bax-mediated OPC death. To identify other Bax-binding partners, we used proteomics and identified cofilin as a Bax-associated protein in OPCs. Cofilin and Bax associated in healthy OPCs, whereas the Bax-cofilin association was disrupted during glutamate-induced OPC apoptosis.
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Key Words
- apoptosis
- bcl-xl
- bid
- cofilin
- insulin-like growth factor 1 (igf-i)
- oligodendrocyte
- acn, acetonitrile
- adf, actin depolymerizing factor
- af488, alexa fluor 488
- af546, alexa fluor 546
- cca, common carotid artery
- cl, contralateral
- cns, central nervous system
- dmem, dulbecco’s modified eagle’s medium
- fbs, fetal bovine serum
- fgf-2, fibroblast growth factor-2
- h–i, hypoxia–ischemia
- igf, insulin-like growth factor
- il, ipsilateral
- ip, immunoprecipitation
- mem, minimal essential media
- opc, oligodendrocyte progenitor cell
- pic, protease inhibitor cocktail
- tbid, truncated bid
- vdac, voltage-dependent anion channel
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Affiliation(s)
- Sopio Simonishvili
- *Department of Neurology & Neuroscience, New Jersey Medical School Cancer Center, Rutgers Biomedical & Health Sciences, Newark, NJ 07101, U.S.A
| | - Mohit Raja Jain
- †Center for Advanced Proteomic Research and Department of Biochemistry and Molecular Biology, New Jersey Medical School Cancer Center, Rutgers Biomedical & Health Sciences, Newark, NJ 07101, U.S.A
| | - Hong Li
- †Center for Advanced Proteomic Research and Department of Biochemistry and Molecular Biology, New Jersey Medical School Cancer Center, Rutgers Biomedical & Health Sciences, Newark, NJ 07101, U.S.A
| | - Steven W. Levison
- *Department of Neurology & Neuroscience, New Jersey Medical School Cancer Center, Rutgers Biomedical & Health Sciences, Newark, NJ 07101, U.S.A
| | - Teresa L. Wood
- *Department of Neurology & Neuroscience, New Jersey Medical School Cancer Center, Rutgers Biomedical & Health Sciences, Newark, NJ 07101, U.S.A
- 1To whom correspondence should be addressed (email )
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25
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Building blocks of the apoptotic pore: how Bax and Bak are activated and oligomerize during apoptosis. Cell Death Differ 2013; 21:196-205. [PMID: 24162660 DOI: 10.1038/cdd.2013.139] [Citation(s) in RCA: 283] [Impact Index Per Article: 25.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2013] [Revised: 09/03/2013] [Accepted: 09/03/2013] [Indexed: 12/18/2022] Open
Abstract
The central role of the Bcl-2 family in regulating apoptotic cell death was first identified in the 1980s. Since then, significant in-roads have been made in identifying the multiple members of this family, characterizing their form and function and understanding how their interactions determine whether a cell lives or dies. In this review we focus on the recent progress made in characterizing the proapoptotic Bcl-2 family members, Bax and Bak. This progress has resolved longstanding controversies, but has also challenged established theories in the apoptosis field. We will discuss different models of how these two proteins become activated and different 'modes' by which they are inhibited by other Bcl-2 family members. We will also discuss novel conformation changes leading to Bak and Bax oligomerization and speculate how these oligomers might permeabilize the mitochondrial outer membrane.
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Apoptosis induced by the fungal pathogen gliotoxin requires a triple phosphorylation of Bim by JNK. Cell Death Differ 2013; 20:1317-29. [PMID: 23832115 DOI: 10.1038/cdd.2013.78] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2012] [Revised: 04/30/2013] [Accepted: 05/27/2013] [Indexed: 01/03/2023] Open
Abstract
We previously reported that gliotoxin (GT), the major virulence factor of the mold Aspergillus fumigatus causing invasive aspergillosis (IA) in immunocompromised patients, induces apoptosis in a Bak-dependent manner. The signaling pathway leading to Bak activation and subsequent mitochondrial outer membrane permeabilization (MOMP) is elusive. Here, we show that GT and the supernatant of A. fumigatus (but not its GT-defective mutant) activate the JNK pathway and require a co-operative JNK-mediated BimEL phosphorylation at three sites (S100, T112 and S114) to induce apoptosis in mouse fibroblasts, human bronchial and mouse alveolar epithelial cells. Cells (i) treated with the JNK inhibitor SP600125, (ii) deleted or knocked down for JNK1/2 or Bim or (iii) carrying the BimEL triple phosphomutant S100A/T112A/S114A instead of wild-type BimEL are similarly resistant to GT-induced apoptosis. Triple-phosphorylated BimEL is more stable, redistributes from a cytoskeletal to a membrane fraction, better interacts with Bcl-2 and Bcl-xL and more effectively activates Bak than the unphosphorylated mutant. These data indicate that JNK-mediated BimEL phosphorylation at S100, T112 and S114 constitutes a novel regulatory mechanism to activate Bim in response to apoptotic stimuli.
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Apoptosis of osteosarcoma cultures by the combination of the cyclin-dependent kinase inhibitor SCH727965 and a heat shock protein 90 inhibitor. Cell Death Dis 2013; 4:e566. [PMID: 23538447 PMCID: PMC3613821 DOI: 10.1038/cddis.2013.101] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Osteosarcoma (OS) is an aggressive bone cancer typically observed in adolescents and young adults. Metastatic relapse accounts primarily for treatment failure, and obstacles to improving cure rates include a lack of efficacious agents. Our studies show apoptosis of OS cells prepared from localized and metastatic tumors by a novel drug combination: SCH727965 (SCH), a cyclin-dependent kinase inhibitor, and NVP-AUY922 (AUY) or other heat shock protein 90 inhibitor. SCH and AUY induced apoptosis when added simultaneously to cells and when AUY was added to and removed from cells before SCH addition. Sequential treatment was most effective when cells received AUY for ~12 h and when SCH was presented to cells immediately after AUY removal. The apoptotic protein Bax accumulated in mitochondria of cotreated cells but was primarily cytosolic in cells receiving either agent alone. Additional data show that SCH and AUY cooperatively induce the apoptosis of other sarcoma cell types but not of normal osteoblasts or fibroblasts, and that SCH and AUY individually inhibit cell cycle progression throughout the cell cycle. We suggest that the combination of SCH and AUY may be an effective new strategy for treatment of OS.
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Matthews GM, Newbold A, Johnstone RW. Intrinsic and extrinsic apoptotic pathway signaling as determinants of histone deacetylase inhibitor antitumor activity. Adv Cancer Res 2013; 116:165-97. [PMID: 23088871 DOI: 10.1016/b978-0-12-394387-3.00005-7] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Histone deacetylase inhibitors (HDACi) can elicit a range of biological responses that impede the growth and/or survival of tumor cells. Depending on the physiological context, HDACi can induce apoptosis via two well-defined apoptotic pathways; the intrinsic/mitochondrial pathway and the death receptor (DR)/extrinsic pathway. A number of groups have demonstrated that overexpression of prosurvival Bcl-2 family members significantly reduces HDACi-mediated tumor cell death and therapeutic efficacy in preclinical models. In many cases, HDACi activate the intrinsic pathway via upregulation of a number of proapoptotic BH3-only Bcl-2 family genes including Bim, Bid, and Bmf. Additionally, HDACi can engage the extrinsic pathway through upregulation of DR expression, reductions in c-FLIP, and upregulation of ligands such as TRAIL. Overall, it appears that activation of the intrinsic apoptotic pathway is the predominant mechanism of HDACi-induced tumor cell death; however, the DR pathway may also be engaged, either to amplify the apoptotic signal through the intrinsic pathway or to directly induce cell death.
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Affiliation(s)
- Geoffrey M Matthews
- Cancer Therapeutics Program, Gene Regulation Laboratory, The Peter MacCallum Cancer Centre, St. Andrews Place, East Melbourne, Victoria, Australia
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Werneburg NW, Bronk SF, Guicciardi ME, Thomas L, Dikeakos JD, Thomas G, Gores GJ. Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) protein-induced lysosomal translocation of proapoptotic effectors is mediated by phosphofurin acidic cluster sorting protein-2 (PACS-2). J Biol Chem 2012; 287:24427-37. [PMID: 22645134 DOI: 10.1074/jbc.m112.342238] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-induced apoptosis of liver cancer cell lines requires death receptor-5 (DR5)-dependent permeabilization of lysosomal membranes. Ligated DR5 triggers recruitment of the proapoptotic proteins Bim and Bax to lysosomes, releasing cathepsin B into the cytosol where it mediates mitochondria membrane permeabilization and activation of executioner caspases. Despite the requirement for lysosome membrane permeabilization during TRAIL-induced apoptosis, little is known about the mechanism that controls recruitment of Bim and Bax to lysosomal membranes. Here we report that TRAIL induces recruitment of the multifunctional sorting protein phosphofurin acidic cluster sorting protein-2 (PACS-2) to DR5-positive endosomes in Huh-7 cells where it forms an immunoprecipitatable complex with Bim and Bax on lysosomal membranes. shRNA-targeted knockdown of PACS-2 prevents recruitment of Bim or Bax to lysosomes, blunting the TRAIL-induced lysosome membrane permeabilization. Consistent with the reduced lysosome membrane permeabilization, shRNA knockdown of PACS-2 in Huh-7 cells reduced TRAIL-induced apoptosis and increased clonogenic cell survival. The determination that recombinant PACS-2 bound Bim but not Bax in vitro and that shRNA knockdown of Bim blocked Bax recruitment to lysosomes suggests that TRAIL/DR5 triggers endosomal PACS-2 to recruit Bim and Bax to lysosomes to release cathepsin B and induce apoptosis. Together, these findings provide insight into the lysosomal pathway of apoptosis.
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Affiliation(s)
- Nathan W Werneburg
- Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, Minnesota 55905, USA
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