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Tencer AH, Yu Y, Causse SZ, Campbell GR, Klein BJ, Xuan H, Cartier J, Miles MA, Gaurav N, Zadoroznyj A, Holt TA, Wen H, Hawkins CJ, Spector SA, Dubrez L, Shi X, Kutateladze TG. Molecular basis for nuclear accumulation and targeting of the inhibitor of apoptosis BIRC2. Nat Struct Mol Biol 2023; 30:1265-1274. [PMID: 37524969 PMCID: PMC10702411 DOI: 10.1038/s41594-023-01044-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Accepted: 06/26/2023] [Indexed: 08/02/2023]
Abstract
The inhibitor of apoptosis protein BIRC2 regulates fundamental cell death and survival signaling pathways. Here we show that BIRC2 accumulates in the nucleus via binding of its second and third BIR domains, BIRC2BIR2 and BIRC2BIR3, to the histone H3 tail and report the structure of the BIRC2BIR3-H3 complex. RNA-seq analysis reveals that the genes involved in interferon and defense response signaling and cell-cycle regulation are most affected by depletion of BIRC2. Overexpression of BIRC2 delays DNA damage repair and recovery of the cell-cycle progression. We describe the structural mechanism for targeting of BIRC2BIR3 by a potent but biochemically uncharacterized small molecule inhibitor LCL161 and demonstrate that LCL161 disrupts the association of endogenous BIRC2 with H3 and stimulates cell death in cancer cells. We further show that LCL161 mediates degradation of BIRC2 in human immunodeficiency virus type 1-infected human CD4+ T cells. Our findings provide mechanistic insights into the nuclear accumulation of and blocking BIRC2.
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Affiliation(s)
- Adam H Tencer
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO, USA
| | - Yucong Yu
- Department of Epigenetics, Van Andel Research Institute, Grand Rapids, MI, USA
| | - Sebastien Z Causse
- Institut National de la Santé et de la Recherche Médicale (Inserm), LNC UMR1231, Dijon, France and Université de Bourgogne Franche-Comté, Dijon, France
| | - Grant R Campbell
- Division of Infectious Diseases, Department of Pediatrics, University of California San Diego, La Jolla, CA, USA
- Division of Basic Biomedical Sciences, Sanford School of Medicine, University of South Dakota, Vermillion, SD, USA
| | - Brianna J Klein
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO, USA
| | - Hongwen Xuan
- Department of Epigenetics, Van Andel Research Institute, Grand Rapids, MI, USA
| | - Jessy Cartier
- Institut National de la Santé et de la Recherche Médicale (Inserm), LNC UMR1231, Dijon, France and Université de Bourgogne Franche-Comté, Dijon, France
| | - Mark A Miles
- Department of Biochemistry and Chemistry, La Trobe Institute for Molecular Science, La Trobe University, Bundoora, Victoria, Australia
| | - Nitika Gaurav
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO, USA
| | - Aymeric Zadoroznyj
- Institut National de la Santé et de la Recherche Médicale (Inserm), LNC UMR1231, Dijon, France and Université de Bourgogne Franche-Comté, Dijon, France
| | - Tina A Holt
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO, USA
| | - Hong Wen
- Department of Epigenetics, Van Andel Research Institute, Grand Rapids, MI, USA
| | - Christine J Hawkins
- Department of Biochemistry and Chemistry, La Trobe Institute for Molecular Science, La Trobe University, Bundoora, Victoria, Australia
| | - Stephen A Spector
- Division of Infectious Diseases, Department of Pediatrics, University of California San Diego, La Jolla, CA, USA.
- Rady Children's Hospital, San Diego, CA, USA.
| | - Laurence Dubrez
- Institut National de la Santé et de la Recherche Médicale (Inserm), LNC UMR1231, Dijon, France and Université de Bourgogne Franche-Comté, Dijon, France.
| | - Xiaobing Shi
- Department of Epigenetics, Van Andel Research Institute, Grand Rapids, MI, USA.
| | - Tatiana G Kutateladze
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO, USA.
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Ji Y, Hawkins CJ. Reconstitution of human pyroptotic cell death in Saccharomyces cerevisiae. Sci Rep 2023; 13:3095. [PMID: 36813876 PMCID: PMC9946934 DOI: 10.1038/s41598-023-29464-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Accepted: 02/06/2023] [Indexed: 02/24/2023] Open
Abstract
Pyroptosis is a lytic form of programmed cell death induced by the activation of gasdermins. The precise mechanism of gasdermin activation by upstream proteases remains incompletely understood. Here, we reconstituted human pyroptotic cell death in yeast by inducible expression of caspases and gasdermins. Functional interactions were reflected by the detection of cleaved gasdermin-D (GSDMD) and gasdermin-E (GSDME), plasma membrane permeabilization, and reduced growth and proliferative potential. Following overexpression of human caspases-1, -4, -5, and -8, GSDMD was cleaved. Similarly, active caspase-3 induced proteolytic cleavage of co-expressed GSDME. Caspase-mediated cleavage of GSDMD or GSDME liberated the ~ 30 kDa cytotoxic N-terminal fragments of these proteins, permeabilized the plasma membrane and compromised yeast growth and proliferation potential. Interestingly, the observation of yeast lethality mediated by co-expression of caspases-1 or -2 with GSDME signified functional cooperation between these proteins in yeast. The small molecule pan-caspase inhibitor Q-VD-OPh reduced caspase-mediated yeast toxicity, allowing us to expand the utility of this yeast model to investigate the activation of gasdermins by caspases that would otherwise be highly lethal to yeast. These yeast biological models provide handy platforms to study pyroptotic cell death and to screen for and characterize potential necroptotic inhibitors.
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Affiliation(s)
- Yanhao Ji
- grid.1018.80000 0001 2342 0938Department of Biochemistry and Chemistry, La Trobe Institute for Molecular Science, La Trobe University, Bundoora, VIC Australia
| | - Christine J. Hawkins
- grid.1018.80000 0001 2342 0938Department of Biochemistry and Chemistry, La Trobe Institute for Molecular Science, La Trobe University, Bundoora, VIC Australia
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Cerra C, Harris MA, Hawkins CJ. Establishment and Characterisation of Metastatic Extraskeletal Ewing Sarcoma Mouse Models. In Vivo 2021; 35:3097-3106. [PMID: 34697140 DOI: 10.21873/invivo.12604] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Revised: 08/05/2021] [Accepted: 08/06/2021] [Indexed: 11/10/2022]
Abstract
BACKGROUND/AIM Ewing sarcomas most commonly arise in the bones, but can also manifest as extraskeletal tumours in soft tissues. Metastases from extraskeletal Ewing sarcomas occur in more diverse anatomical sites than skeletal tumours, and have poorer survival rates. Few animal models replicate the extraskeletal form of Ewing sarcoma, and those that have been developed do not reflect the widespread metastatic spread of these cancers. MATERIALS AND METHODS Luciferase-expressing Ewing sarcoma cells derived from a muscle tumour were intramuscularly or intravenously injected into nude mice. RESULTS Both models achieved metastatic spread to numerous sites including the lungs, liver, kidneys, and brain. We characterized the cellular composition of primary and metastatic tumours, observing a greater level of immune cell infiltration in metastases compared to primary intramuscular tumours. CONCLUSION These pre-clinical models will hopefully facilitate the evaluation of novel therapies and contribute to better understanding the disease progression of metastatic extraskeletal Ewing sarcoma.
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Affiliation(s)
- Carmelo Cerra
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC, Australia
| | - Michael A Harris
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC, Australia
| | - Christine J Hawkins
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC, Australia
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Samuel M, Fonseka P, Sanwlani R, Gangoda L, Chee SH, Keerthikumar S, Spurling A, Chitti SV, Zanker D, Ang CS, Atukorala I, Kang T, Shahi S, Marzan AL, Nedeva C, Vennin C, Lucas MC, Cheng L, Herrmann D, Pathan M, Chisanga D, Warren SC, Zhao K, Abraham N, Anand S, Boukouris S, Adda CG, Jiang L, Shekhar TM, Baschuk N, Hawkins CJ, Johnston AJ, Orian JM, Hoogenraad NJ, Poon IK, Hill AF, Jois M, Timpson P, Parker BS, Mathivanan S. Oral administration of bovine milk-derived extracellular vesicles induces senescence in the primary tumor but accelerates cancer metastasis. Nat Commun 2021; 12:3950. [PMID: 34168137 PMCID: PMC8225634 DOI: 10.1038/s41467-021-24273-8] [Citation(s) in RCA: 57] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Accepted: 06/09/2021] [Indexed: 01/06/2023] Open
Abstract
The concept that extracellular vesicles (EVs) from the diet can be absorbed by the intestinal tract of the consuming organism, be bioavailable in various organs, and in-turn exert phenotypic changes is highly debatable. Here, we isolate EVs from both raw and commercial bovine milk and characterize them by electron microscopy, nanoparticle tracking analysis, western blotting, quantitative proteomics and small RNA sequencing analysis. Orally administered bovine milk-derived EVs survive the harsh degrading conditions of the gut, in mice, and is subsequently detected in multiple organs. Milk-derived EVs orally administered to mice implanted with colorectal and breast cancer cells reduce the primary tumor burden. Intriguingly, despite the reduction in primary tumor growth, milk-derived EVs accelerate metastasis in breast and pancreatic cancer mouse models. Proteomic and biochemical analysis reveal the induction of senescence and epithelial-to-mesenchymal transition in cancer cells upon treatment with milk-derived EVs. Timing of EV administration is critical as oral administration after resection of the primary tumor reverses the pro-metastatic effects of milk-derived EVs in breast cancer models. Taken together, our study provides context-based and opposing roles of milk-derived EVs as metastasis inducers and suppressors.
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Affiliation(s)
- Monisha Samuel
- Department of Physiology, Anatomy and Microbiology, School of Life Sciences, La Trobe University, Bundoora, VIC, Australia
| | - Pamali Fonseka
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC, Australia
| | - Rahul Sanwlani
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC, Australia
| | - Lahiru Gangoda
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC, Australia
| | - Sing Ho Chee
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC, Australia
| | - Shivakumar Keerthikumar
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC, Australia
- Cancer Research Division, Peter MacCallum Cancer Centre, Melbourne, VIC, Australia
- Sir Peter MacCallum Department of Oncology, University of Melbourne, Melbourne, VIC, Australia
| | - Alex Spurling
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC, Australia
| | - Sai V Chitti
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC, Australia
| | - Damien Zanker
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC, Australia
| | - Ching-Seng Ang
- Bio21 Institute, University of Melbourne, Melbourne, VIC, Australia
| | - Ishara Atukorala
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC, Australia
| | - Taeyoung Kang
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC, Australia
| | - Sanjay Shahi
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC, Australia
| | - Akbar L Marzan
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC, Australia
| | - Christina Nedeva
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC, Australia
| | - Claire Vennin
- Garvan Institute of Medical Research, The Kinghorn Cancer Centre & St Vincent's Clinical School, Faculty of Medicine, University of New South Wales, Sydney, NSW, Australia
| | - Morghan C Lucas
- Garvan Institute of Medical Research, The Kinghorn Cancer Centre & St Vincent's Clinical School, Faculty of Medicine, University of New South Wales, Sydney, NSW, Australia
| | - Lesley Cheng
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC, Australia
| | - David Herrmann
- Garvan Institute of Medical Research, The Kinghorn Cancer Centre & St Vincent's Clinical School, Faculty of Medicine, University of New South Wales, Sydney, NSW, Australia
| | - Mohashin Pathan
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC, Australia
| | - David Chisanga
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC, Australia
| | - Sean C Warren
- Garvan Institute of Medical Research, The Kinghorn Cancer Centre & St Vincent's Clinical School, Faculty of Medicine, University of New South Wales, Sydney, NSW, Australia
| | - Kening Zhao
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC, Australia
| | - Nidhi Abraham
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC, Australia
| | - Sushma Anand
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC, Australia
| | - Stephanie Boukouris
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC, Australia
| | - Christopher G Adda
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC, Australia
| | - Lanzhou Jiang
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC, Australia
| | - Tanmay M Shekhar
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC, Australia
| | - Nikola Baschuk
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC, Australia
| | - Christine J Hawkins
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC, Australia
| | - Amelia J Johnston
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC, Australia
| | - Jacqueline Monique Orian
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC, Australia
| | - Nicholas J Hoogenraad
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC, Australia
| | - Ivan K Poon
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC, Australia
| | - Andrew F Hill
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC, Australia
| | - Markandeya Jois
- Department of Physiology, Anatomy and Microbiology, School of Life Sciences, La Trobe University, Bundoora, VIC, Australia
| | - Paul Timpson
- Garvan Institute of Medical Research, The Kinghorn Cancer Centre & St Vincent's Clinical School, Faculty of Medicine, University of New South Wales, Sydney, NSW, Australia
| | - Belinda S Parker
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC, Australia
| | - Suresh Mathivanan
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC, Australia.
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Hawkins CJ, Miles MA. Mutagenic Consequences of Sublethal Cell Death Signaling. Int J Mol Sci 2021; 22:ijms22116144. [PMID: 34200309 PMCID: PMC8201051 DOI: 10.3390/ijms22116144] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Revised: 06/03/2021] [Accepted: 06/05/2021] [Indexed: 02/06/2023] Open
Abstract
Many human cancers exhibit defects in key DNA damage response elements that can render tumors insensitive to the cell death-promoting properties of DNA-damaging therapies. Using agents that directly induce apoptosis by targeting apoptotic components, rather than relying on DNA damage to indirectly stimulate apoptosis of cancer cells, may overcome classical blocks exploited by cancer cells to evade apoptotic cell death. However, there is increasing evidence that cells surviving sublethal exposure to classical apoptotic signaling may recover with newly acquired genomic changes which may have oncogenic potential, and so could theoretically spur the development of subsequent cancers in cured patients. Encouragingly, cells surviving sublethal necroptotic signaling did not acquire mutations, suggesting that necroptosis-inducing anti-cancer drugs may be less likely to trigger therapy-related cancers. We are yet to develop effective direct inducers of other cell death pathways, and as such, data regarding the consequences of cells surviving sublethal stimulation of those pathways are still emerging. This review details the currently known mutagenic consequences of cells surviving different cell death signaling pathways, with implications for potential oncogenic transformation. Understanding the mechanisms of mutagenesis associated (or not) with various cell death pathways will guide us in the development of future therapeutics to minimize therapy-related side effects associated with DNA damage.
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Affiliation(s)
- Christine J. Hawkins
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Bundoora, VIC 3086, Australia;
| | - Mark A. Miles
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Bundoora, VIC 3086, Australia;
- School of Health and Biomedical Sciences, RMIT University, Bundoora, VIC 3083, Australia
- Correspondence:
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Abstract
Smac mimetics, or IAP antagonists, are a class of drugs currently being evaluated as anti-cancer therapeutics. These agents antagonize IAP proteins, including cIAP1/2 and XIAP, to induce cell death via apoptotic or, upon caspase-8 deficiency, necroptotic cell death pathways. Many cancer cells are unresponsive to Smac mimetic treatment as a single agent but can be sensitized to killing in the presence of the cytokine TNFα, provided either exogenously or via autocrine production. We found that high concentrations of a subset of Smac mimetics could provoke death in cells that did not produce TNFα, despite sensitization at lower concentrations by TNFα. The ability of these drugs to kill did not correlate with valency. These cells remained responsive to the lethal effects of Smac mimetics at high concentrations despite genetic or pharmacological impairments in apoptotic, necroptotic, pyroptotic, autophagic and ferroptotic cell death pathways. Analysis of dying cells revealed necrotic morphology, which was accompanied by the release of lactate dehydrogenase and cell membrane rupture without prior phosphatidylserine exposure implying cell lysis, which occurred over a several hours. Our study reveals that cells incapable of autocrine TNFα production are sensitive to some Smac mimetic compounds when used at high concentrations, and this exposure elicits a lytic cell death phenotype that occurs via a mechanism not requiring apoptotic caspases or necroptotic effectors RIPK3 or MLKL. These data reveal the possibility that non-canonical cell death pathways can be triggered by these drugs when applied at high concentrations.
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Affiliation(s)
- Mark A Miles
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Bundoora, VIC, 3086, Australia.
| | - Sarah Caruso
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Bundoora, VIC, 3086, Australia
| | - Amy A Baxter
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Bundoora, VIC, 3086, Australia
| | - Ivan K H Poon
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Bundoora, VIC, 3086, Australia
| | - Christine J Hawkins
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Bundoora, VIC, 3086, Australia
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Harris MA, Hons BB, Shekhar TM, Coupland LA, Miles MA, Hawkins CJ. Transient NK Cell Depletion Facilitates Pulmonary Osteosarcoma Metastases After Intravenous Inoculation in Athymic Mice. J Adolesc Young Adult Oncol 2020; 9:667-671. [DOI: 10.1089/jayao.2019.0172] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Affiliation(s)
| | - BBioMed Hons
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Bundoora, Australia
| | - Tanmay M. Shekhar
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Bundoora, Australia
| | - Lucy A. Coupland
- The ACRF Department of Cancer Biology and Therapeutics, The John Curtin School of Medical Research, The Australian National University, Canberra, Australia
| | - Mark A. Miles
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Bundoora, Australia
| | - Christine J. Hawkins
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Bundoora, Australia
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Atkin-Smith GK, Miles MA, Tixeira R, Lay FT, Duan M, Hawkins CJ, Phan TK, Paone S, Mathivanan S, Hulett MD, Chen W, Poon IKH. Plexin B2 Is a Regulator of Monocyte Apoptotic Cell Disassembly. Cell Rep 2020; 29:1821-1831.e3. [PMID: 31722200 DOI: 10.1016/j.celrep.2019.10.014] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [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: 07/18/2019] [Revised: 09/10/2019] [Accepted: 10/03/2019] [Indexed: 12/18/2022] Open
Abstract
Billions of cells undergo apoptosis daily and often fragment into small, membrane-bound extracellular vesicles termed apoptotic bodies (ApoBDs). We demonstrate that apoptotic monocytes undergo a highly coordinated disassembly process and form long, beaded protrusions (coined as beaded apoptopodia), which fragment to release ApoBDs. Here, we find that the protein plexin B2 (PlexB2), a transmembrane receptor that regulates axonal guidance in neurons, is enriched in the ApoBDs of THP1 monocytes and is a caspase 3/7 substrate. To determine whether PlexB2 is involved in the disassembly of apoptotic monocytes, we generate PlexB2-deficient THP1 monocytes and demonstrate that lack of PlexB2 impairs the formation of beaded apoptopodia and ApoBDs. Consequently, the loss of PlexB2 in apoptotic THP1 monocytes impairs their uptake by both professional and non-professional phagocytes. Altogether, these data identify PlexB2 as a positive regulator of apoptotic monocyte disassembly and demonstrate the importance of this process in apoptotic cell clearance.
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Affiliation(s)
- Georgia K Atkin-Smith
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC 3086, Australia
| | - Mark A Miles
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC 3086, Australia
| | - Rochelle Tixeira
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC 3086, Australia
| | - Fung T Lay
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC 3086, Australia
| | - Mubing Duan
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC 3086, Australia
| | - Christine J Hawkins
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC 3086, Australia
| | - Thanh Kha Phan
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC 3086, Australia
| | - Stephanie Paone
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC 3086, Australia
| | - Suresh Mathivanan
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC 3086, Australia
| | - Mark D Hulett
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC 3086, Australia
| | - Weisan Chen
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC 3086, Australia
| | - Ivan K H Poon
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC 3086, Australia.
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Harris MA, Miles MA, Shekhar TM, Cerra C, Georgy SR, Ryan SD, Cannon CM, Hawkins CJ. The Proteasome Inhibitor Ixazomib Inhibits the Formation and Growth of Pulmonary and Abdominal Osteosarcoma Metastases in Mice. Cancers (Basel) 2020; 12:cancers12051207. [PMID: 32403415 PMCID: PMC7281181 DOI: 10.3390/cancers12051207] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Revised: 05/07/2020] [Accepted: 05/08/2020] [Indexed: 12/17/2022] Open
Abstract
Osteosarcoma is the most common form of primary bone cancer. Over 20% of osteosarcoma patients present with pulmonary metastases at diagnosis, and nearly 70% of these patients fail to respond to treatment. Previous work revealed that human and canine osteosarcoma cell lines are extremely sensitive to the therapeutic proteasome inhibitor bortezomib in vitro. However, bortezomib has proven disappointingly ineffective against solid tumors including sarcomas in animal experiments and clinical trials. Poor tumor penetration has been speculated to account for the inconsistency between in vitro and in vivo responses of solid tumors to bortezomib. Here we show that the second-generation proteasome inhibitor ixazomib, which reportedly has enhanced solid tumor penetration compared to bortezomib, is toxic to human and canine osteosarcoma cells in vitro. We used experimental osteosarcoma metastasis models to compare the efficacies of ixazomib and bortezomib against primary tumors and metastases derived from luciferase-expressing KRIB or 143B human osteosarcoma cell lines in athymic mice. Neither proteasome inhibitor reduced the growth of primary intramuscular KRIB tumors, however both drugs inhibited the growth of established pulmonary metastases created via intravenous inoculation with KRIB cells, which were significantly better vascularized than the primary tumors. Only ixazomib slowed metastases from KRIB primary tumors and inhibited the growth of 143B pulmonary and abdominal metastases, significantly enhancing the survival of mice intravenously injected with 143B cells. Taken together, these results suggest ixazomib exerts better single agent activity against osteosarcoma metastases than bortezomib. These data provide hope that incorporation of ixazomib, or other proteasome inhibitors that penetrate efficiently into solid tumors, into current regimens may improve outcomes for patients diagnosed with metastatic osteosarcoma.
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Affiliation(s)
- Michael A. Harris
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, 3086 Victoria, Australia; (M.A.H.); (M.A.M.); (T.M.S.); (C.C.)
| | - Mark A. Miles
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, 3086 Victoria, Australia; (M.A.H.); (M.A.M.); (T.M.S.); (C.C.)
| | - Tanmay M. Shekhar
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, 3086 Victoria, Australia; (M.A.H.); (M.A.M.); (T.M.S.); (C.C.)
| | - Carmelo Cerra
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, 3086 Victoria, Australia; (M.A.H.); (M.A.M.); (T.M.S.); (C.C.)
| | - Smitha R. Georgy
- Department of Anatomic Pathology, Faculty of Veterinary and Agricultural Sciences, University of Melbourne, 3010 Victoria, Australia;
| | - Stewart D. Ryan
- Translational Research and Animal Clinical Trial Study Group (TRACTS), Faculty of Veterinary and Agricultural Sciences, University of Melbourne, 3010 Melbourne, Australia; (S.D.R.); (C.M.C.)
| | - Claire M. Cannon
- Translational Research and Animal Clinical Trial Study Group (TRACTS), Faculty of Veterinary and Agricultural Sciences, University of Melbourne, 3010 Melbourne, Australia; (S.D.R.); (C.M.C.)
| | - Christine J. Hawkins
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, 3086 Victoria, Australia; (M.A.H.); (M.A.M.); (T.M.S.); (C.C.)
- Correspondence: ; Tel.: +61-3-9479-2339
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10
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Miles MA, Harris MA, Hawkins CJ. Proteasome inhibitors trigger mutations via activation of caspases and CAD, but mutagenesis provoked by the HDAC inhibitors vorinostat and romidepsin is caspase/CAD-independent. Apoptosis 2020; 24:404-413. [PMID: 30997620 DOI: 10.1007/s10495-019-01543-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Genotoxic anti-cancer therapies such as chemotherapy and radiotherapy can contribute to an increase in second malignancies in cancer survivors due to their oncogenic effects on non-cancerous cells. Inhibition of histone deacetylase (HDAC) proteins or the proteasome differ from chemotherapy in that they eliminate cancer cells by regulating gene expression or cellular protein equilibrium, respectively. As members of these drug classes have been approved for clinical use in recent times, we investigated whether these two drug classes exhibit similar mutagenic capabilities as chemotherapy. The HDAC inhibitors vorinostat/SAHA and romidepsin/FK288 were found to induce DNA damage, and mis-repair of this damage manifested into mutations in clonogenically viable surviving cells. DNA damage and mutations were also detected in cells treated with the proteasome inhibitor bortezomib. Exposure to both drug classes stimulated caspase activation consistent with apoptotic cell death. Inhibition of caspases protected cells from bortezomib-induced acute (but not clonogenic) death and mutagenesis, implying caspases were required for the mutagenic action of bortezomib. This was also observed for second generation proteasome inhibitors. Cells deficient in caspase-activated DNase (CAD) also failed to acquire DNA damage or mutations following treatment with bortezomib. Surprisingly, vorinostat and romidepsin maintained an equivalent level of killing and mutagenic ability regardless of caspase or CAD activity. Our findings indicate that both drug classes harbour mutagenic potential in vitro. If recapitulated in vivo, the mutagenicity of these agents may influence the treatment of cancer patients who are more susceptible to oncogenic mutations due to dysfunctional DNA repair pathways.
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Affiliation(s)
- Mark A Miles
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Bundoora, Melbourne, VIC, 3086, Australia.
| | - Michael A Harris
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Bundoora, Melbourne, VIC, 3086, Australia
| | - Christine J Hawkins
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Bundoora, Melbourne, VIC, 3086, Australia
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11
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Shekhar TM, Burvenich IJG, Harris MA, Rigopoulos A, Zanker D, Spurling A, Parker BS, Walkley CR, Scott AM, Hawkins CJ. Smac mimetics LCL161 and GDC-0152 inhibit osteosarcoma growth and metastasis in mice. BMC Cancer 2019; 19:924. [PMID: 31521127 PMCID: PMC6744692 DOI: 10.1186/s12885-019-6103-5] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Accepted: 08/28/2019] [Indexed: 12/14/2022] Open
Abstract
Background Current therapies fail to cure over a third of osteosarcoma patients and around three quarters of those with metastatic disease. “Smac mimetics” (also known as “IAP antagonists”) are a new class of anti-cancer agents. Previous work revealed that cells from murine osteosarcomas were efficiently sensitized by physiologically achievable concentrations of some Smac mimetics (including GDC-0152 and LCL161) to killing by the inflammatory cytokine TNFα in vitro, but survived exposure to Smac mimetics as sole agents. Methods Nude mice were subcutaneously or intramuscularly implanted with luciferase-expressing murine 1029H or human KRIB osteosarcoma cells. The impacts of treatment with GDC-0152, LCL161 and/or doxorubicin were assessed by caliper measurements, bioluminescence, 18FDG-PET and MRI imaging, and by weighing resected tumors at the experimental endpoint. Metastatic burden was examined by quantitative PCR, through amplification of a region of the luciferase gene from lung DNA. ATP levels in treated and untreated osteosarcoma cells were compared to assess in vitro sensitivity. Immunophenotyping of cells within treated and untreated tumors was performed by flow cytometry, and TNFα levels in blood and tumors were measured using cytokine bead arrays. Results Treatment with GDC-0152 or LCL161 suppressed the growth of subcutaneously or intramuscularly implanted osteosarcomas. In both models, co-treatment with doxorubicin and Smac mimetics impeded average osteosarcoma growth to a greater extent than either drug alone, although these differences were not statistically significant. Co-treatments were also more toxic. Co-treatment with LCL161 and doxorubicin was particularly effective in the KRIB intramuscular model, impeding primary tumor growth and delaying or preventing metastasis. Although the Smac mimetics were effective in vivo, in vitro they only efficiently killed osteosarcoma cells when TNFα was supplied. Implanted tumors contained high levels of TNFα, produced by infiltrating immune cells. Spontaneous osteosarcomas that arose in genetically-engineered immunocompetent mice also contained abundant TNFα. Conclusions These data imply that Smac mimetics can cooperate with TNFα secreted by tumor-associated immune cells to kill osteosarcoma cells in vivo. Smac mimetics may therefore benefit osteosarcoma patients whose tumors contain Smac mimetic-responsive cancer cells and TNFα-producing infiltrating cells.
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Affiliation(s)
- Tanmay M Shekhar
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Bundoora, Victoria, 3086, Australia
| | - Ingrid J G Burvenich
- Tumour Targeting Laboratory, Ludwig Institute for Cancer Research and Olivia Newton-John Cancer Research Institute, Melbourne, Australia.,School of Cancer Medicine, La Trobe University, Melbourne, Australia
| | - Michael A Harris
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Bundoora, Victoria, 3086, Australia
| | - Angela Rigopoulos
- Tumour Targeting Laboratory, Ludwig Institute for Cancer Research and Olivia Newton-John Cancer Research Institute, Melbourne, Australia.,School of Cancer Medicine, La Trobe University, Melbourne, Australia
| | - Damien Zanker
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Bundoora, Victoria, 3086, Australia
| | - Alex Spurling
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Bundoora, Victoria, 3086, Australia
| | - Belinda S Parker
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Bundoora, Victoria, 3086, Australia
| | - Carl R Walkley
- St. Vincent's Institute, Fitzroy, Victoria, 3065, Australia.,Department of Medicine, St. Vincent's Hospital, University of Melbourne, Fitzroy, Victoria, 3065, Australia.,Mary MacKillop Institute for Health Research, Australian Catholic University, Melbourne, Victoria, 3000, Australia
| | - Andrew M Scott
- Tumour Targeting Laboratory, Ludwig Institute for Cancer Research and Olivia Newton-John Cancer Research Institute, Melbourne, Australia.,School of Cancer Medicine, La Trobe University, Melbourne, Australia.,Departments of Medical Oncology and Molecular Imaging & Therapy, Austin Health, Heidelberg, Melbourne, Australia.,Department of Medicine, University of Melbourne, Melbourne, Australia
| | - Christine J Hawkins
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Bundoora, Victoria, 3086, Australia.
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12
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Miles MA, Hawkins CJ. Mutagenic assessment of chemotherapy and Smac mimetic drugs in cells with defective DNA damage response pathways. Sci Rep 2018; 8:14421. [PMID: 30258062 PMCID: PMC6158240 DOI: 10.1038/s41598-018-32517-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [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: 02/07/2018] [Accepted: 09/05/2018] [Indexed: 12/15/2022] Open
Abstract
DNA damaging therapies can spur the formation of therapy-related cancers, due to mis-repair of lesions they create in non-cancerous cells. This risk may be amplified in patients with impaired DNA damage responses. We disabled key DNA damage response pathways using genetic and pharmacological approaches, and assessed the impact of these deficiencies on the mutagenicity of chemotherapy drugs or the "Smac mimetic" GDC-0152, which kills tumor cells by targeting XIAP, cIAP1 and 2. Doxorubicin and cisplatin provoked mutations in more surviving cells deficient in ATM, p53 or the homologous recombination effector RAD51 than in wild type cells, but suppressing non-homologous end joining (NHEJ) by disabling DNA-PKcs prevented chemotherapy-induced mutagenesis. Vincristine-induced mutagenesis required p53 and DNA-PKcs but was not affected by ATM status, consistent with it provoking ATM-independent p53-mediated activation of caspases and CAD, which creates DNA lesions in surviving cells that could be mis-repaired by NHEJ. Encouragingly, GDC-0152 failed to stimulate mutations in cells with proficient or defective DNA damage response pathways. This study highlights the elevated oncogenic risk associated with treating DNA repair-deficient patients with genotoxic anti-cancer therapies, and suggests a potential advantage for Smac mimetic drugs over traditional therapies: a reduced risk of therapy-related cancers.
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Affiliation(s)
- Mark A Miles
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Victoria, Australia
| | - Christine J Hawkins
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Victoria, Australia.
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13
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Patatsos K, Shekhar TM, Hawkins CJ. Pre-clinical evaluation of proteasome inhibitors for canine and human osteosarcoma. Vet Comp Oncol 2018; 16:544-553. [PMID: 29998615 DOI: 10.1111/vco.12413] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2017] [Revised: 04/30/2018] [Accepted: 05/29/2018] [Indexed: 12/12/2022]
Abstract
Osteosarcoma, a common malignancy in large dog breeds, typically metastasises from long bones to lungs and is usually fatal within 1 to 2 years of diagnosis. Better therapies are needed for canine patients and their human counterparts, a third of whom die within 5 years of diagnosis. We compared the in vitro sensitivity of canine osteosarcoma cells derived from 4 tumours to the currently used chemotherapy drugs doxorubicin and carboplatin, and 4 new anti-cancer drugs. Agents targeting histone deacetylases or PARP were ineffective. Two of the 4 cell lines were somewhat sensitive to the BH3-mimetic navitoclax. The proteasome inhibitor bortezomib potently induced caspase-dependent apoptosis, at concentrations substantially lower than levels detected in the bones and lungs of treated rodents. Co-treatment with bortezomib and either doxorubicin or carboplatin was more toxic to canine osteosarcoma cells than each agent alone. Newer proteasome inhibitors carfilzomib, ixazomib, oprozomib and delanzomib manifested similar activities to bortezomib. Human osteosarcoma cells were as sensitive to bortezomib as the canine cells, but slightly less sensitive to the newer drugs. Human osteoblasts were less sensitive to proteasome inhibition than osteosarcoma cells, but physiologically relevant concentrations were toxic. Such toxicity, if replicated in vivo, may impair bone growth and strength in adolescent human osteosarcoma patients, but may be tolerated by canine patients, which are usually diagnosed later in life. Proteasome inhibitors such as bortezomib may be useful for treating canine osteosarcoma, and ultimately may improve outcomes for human patients if their osteoblasts survive exposure in vivo, or if osteoblast toxicity can be managed.
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Affiliation(s)
- K Patatsos
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Australia
| | - T M Shekhar
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Australia
| | - C J Hawkins
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Australia
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14
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Caria S, Marshall B, Burton RL, Campbell S, Pantaki-Eimany D, Hawkins CJ, Barry M, Kvansakul M. The N Terminus of the Vaccinia Virus Protein F1L Is an Intrinsically Unstructured Region That Is Not Involved in Apoptosis Regulation. J Biol Chem 2016; 291:14600-8. [PMID: 27151220 DOI: 10.1074/jbc.m116.726851] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [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: 03/15/2016] [Indexed: 12/21/2022] Open
Abstract
Subversion of host cell apoptotic responses is a prominent feature of viral immune evasion strategies to prevent premature clearance of infected cells. Numerous poxviruses encode structural and functional homologs of the Bcl-2 family of proteins, and vaccinia virus harbors antiapoptotic F1L that potently inhibits the mitochondrial apoptotic checkpoint. Recently F1L has been assigned a caspase-9 inhibitory function attributed to an N-terminal α helical region of F1L spanning residues 1-15 (1) preceding the domain-swapped Bcl-2-like domains. Using a reconstituted caspase inhibition assay in yeast we found that unlike AcP35, a well characterized caspase-9 inhibitor from the insect virus Autographa californica multiple nucleopolyhedrovirus, F1L does not prevent caspase-9-mediated yeast cell death. Furthermore, we found that deletion of the F1L N-terminal region does not impede F1L antiapoptotic activity in the context of a viral infection. Solution analysis of the F1L N-terminal regions using small angle x-ray scattering indicates that the region of F1L spanning residues 1-50 located N-terminally from the Bcl-2 fold is an intrinsically unstructured region. We conclude that the N terminus of F1L is not involved in apoptosis inhibition and may act as a regulatory element in other signaling pathways in a manner reminiscent of other unstructured regulatory elements commonly found in mammalian prosurvival Bcl-2 members including Bcl-xL and Mcl-1.
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Affiliation(s)
- Sofia Caria
- From the La Trobe Institute for Molecular Science, Department of Biochemistry and Genetics, La Trobe University, Victoria 3086, Australia and
| | - Bevan Marshall
- From the La Trobe Institute for Molecular Science, Department of Biochemistry and Genetics, La Trobe University, Victoria 3086, Australia and
| | - Robyn-Lee Burton
- Li Ka Shing Institute for Virology, Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, Alberta T6G 2S2, Canada
| | - Stephanie Campbell
- Li Ka Shing Institute for Virology, Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, Alberta T6G 2S2, Canada
| | - Delara Pantaki-Eimany
- From the La Trobe Institute for Molecular Science, Department of Biochemistry and Genetics, La Trobe University, Victoria 3086, Australia and
| | - Christine J Hawkins
- From the La Trobe Institute for Molecular Science, Department of Biochemistry and Genetics, La Trobe University, Victoria 3086, Australia and
| | - Michele Barry
- Li Ka Shing Institute for Virology, Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, Alberta T6G 2S2, Canada
| | - Marc Kvansakul
- From the La Trobe Institute for Molecular Science, Department of Biochemistry and Genetics, La Trobe University, Victoria 3086, Australia and
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15
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Miles MA, Shekhar TM, Hall NE, Hawkins CJ. TRAIL causes deletions at the HPRT and TK1 loci of clonogenically competent cells. Mutat Res 2016; 787:15-31. [PMID: 26943263 DOI: 10.1016/j.mrfmmm.2016.02.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [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: 11/06/2015] [Revised: 01/05/2016] [Accepted: 02/02/2016] [Indexed: 12/22/2022]
Abstract
When chemotherapy and radiotherapy are effective, they function by inducing DNA damage in cancerous cells, which respond by undergoing apoptosis. Some adverse effects can result from collateral destruction of non-cancerous cells, via the same mechanism. Therapy-related cancers, a particularly serious adverse effect of anti-cancer treatments, develop due to oncogenic mutations created in non-cancerous cells by the DNA damaging therapies used to eliminate the original cancer. Physiologically achievable concentrations of direct apoptosis inducing anti-cancer drugs that target Bcl-2 and IAP proteins possess negligible mutagenic activity, however death receptor agonists like TRAIL/Apo2L can provoke mutations in surviving cells, probably via caspase-mediated activation of the nuclease CAD. In this study we compared the types of mutations sustained in the HPRT and TK1 loci of clonogenically competent cells following treatment with TRAIL or the alkylating agent ethyl methanesulfonate (EMS). As expected, the loss-of-function mutations in the HPRT or TK1 loci triggered by exposure to EMS were almost all transitions. In contrast, only a minority of the mutations identified in TRAIL-treated clones lacking HPRT or TK1 activity were substitutions. Almost three quarters of the TRAIL-induced mutations were partial or complete deletions of the HPRT or TK1 genes, consistent with sub-lethal TRAIL treatment provoking double strand breaks, which may be mis-repaired by non-homologous end joining (NHEJ). Mis-repair of double-strand breaks following exposure to chemotherapy drugs has been implicated in the pathogenesis of therapy-related cancers. These data suggest that TRAIL too may provoke oncogenic damage to the genomes of surviving cells.
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Affiliation(s)
- Mark A Miles
- Department of Biochemistry and Genetics, La Trobe University, Bundoora, Victoria, Australia; La Trobe Institute for Molecular Science, La Trobe University, Bundoora, Victoria, Australia
| | - Tanmay M Shekhar
- Department of Biochemistry and Genetics, La Trobe University, Bundoora, Victoria, Australia; La Trobe Institute for Molecular Science, La Trobe University, Bundoora, Victoria, Australia
| | - Nathan E Hall
- La Trobe Institute for Molecular Science, La Trobe University, Bundoora, Victoria, Australia; Life Sciences Computation Centre, Victorian Life Sciences Computation Initiative, Melbourne, Victoria, Australia
| | - Christine J Hawkins
- Department of Biochemistry and Genetics, La Trobe University, Bundoora, Victoria, Australia; La Trobe Institute for Molecular Science, La Trobe University, Bundoora, Victoria, Australia.
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16
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Green MM, Shekhar TM, Hawkins CJ. Data on the DNA damaging and mutagenic potential of the BH3-mimetics ABT-263/Navitoclax and TW-37. Data Brief 2016; 6:710-4. [PMID: 26958630 PMCID: PMC4773390 DOI: 10.1016/j.dib.2016.01.013] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2015] [Revised: 01/05/2016] [Accepted: 01/08/2016] [Indexed: 11/16/2022] Open
Abstract
Unfortunately, the mutagenic activities of chemotherapy and radiotherapy can provoke development of therapy-induced malignancies in cancer survivors. Non-mutagenic anti-cancer therapies may be less likely to trigger subsequent malignant neoplasms. Here we present data regarding the DNA damaging and mutagenic potential of two drugs that antagonize proteins within the Bcl-2 family: ABT-263/Navitoclax and TW-37. Our data reveal that concentrations of these agents that stimulated Bax/Bak-dependent signaling provoked little DNA damage and failed to trigger mutations in surviving cells. The data supplied in this article is related to the research work entitled "Inhibition of Bcl-2 or IAP proteins does not provoke mutations in surviving cells" [1].
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Affiliation(s)
- Maja M Green
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria 3086, Australia
| | - Tanmay M Shekhar
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria 3086, Australia
| | - Christine J Hawkins
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria 3086, Australia
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17
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Beaumont TE, Shekhar TM, Kaur L, Pantaki-Eimany D, Kvansakul M, Hawkins CJ. Yeast techniques for modeling drugs targeting Bcl-2 and caspase family members. Cell Death Dis 2013; 4:e619. [PMID: 23640461 PMCID: PMC3674352 DOI: 10.1038/cddis.2013.143] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [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: 11/24/2022]
Abstract
Development of drugs targeting Bcl-2 relatives and caspases, for treating diseases including cancer and inflammatory disorders, often involves measuring interactions with recombinant target molecules, and/or monitoring cancer cell killing in vitro. Here, we present yeast-based methods for evaluating drug-mediated inhibition of Bcl-2 relatives or caspases. Active Bax and caspases kill Saccharomyces cerevisiae, and pro-survival Bcl-2 proteins can inhibit Bax-induced yeast death. By measuring the growth or adenosine triphosphate content of transformants co-expressing Bax with pro-survival Bcl-2 relatives, we found that the Bcl-2 antagonist drugs ABT-737 or ABT-263 abolished Bcl-2 or Bcl-xL function and reduced Bcl-w activity, but failed to inhibit Mcl-1, A1 or the poxvirus orthologs DPV022 and SPPV14. Using this technique, we also demonstrated that adenoviral E1B19K was resistant to these agents. The caspase inhibitor Q-VD-OPh suppressed yeast death induced by caspases 1 and 3. Yeast engineered to express human apoptotic regulators enable simple, automatable assessment of the activity and specificity of candidate drugs targeting Bcl-2 relatives or caspases.
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Affiliation(s)
- T E Beaumont
- Department of Biochemistry, La Trobe Institute for Molecular Science, La Trobe University, Bundoora, Victoria, Australia
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18
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Huang N, Civciristov S, Hawkins CJ, Clem RJ. SfDronc, an initiator caspase involved in apoptosis in the fall armyworm Spodoptera frugiperda. Insect Biochem Mol Biol 2013; 43:444-454. [PMID: 23474489 PMCID: PMC3640372 DOI: 10.1016/j.ibmb.2013.02.005] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [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] [Received: 10/09/2012] [Revised: 01/31/2013] [Accepted: 02/21/2013] [Indexed: 06/01/2023]
Abstract
Initiator caspases are the first caspases that are activated following an apoptotic stimulus, and are responsible for cleaving and activating downstream effector caspases, which directly cause apoptosis. We have cloned a cDNA encoding an ortholog of the initiator caspase Dronc in the lepidopteran insect Spodoptera frugiperda. The SfDronc cDNA encodes a predicted protein of 447 amino acids with a molecular weight of 51 kDa. Overexpression of SfDronc induced apoptosis in Sf9 cells, while partial silencing of SfDronc expression in Sf9 cells reduced apoptosis induced by baculovirus infection or by treatment with UV or actinomycin D. Recombinant SfDronc exhibited several expected biochemical characteristics of an apoptotic initiator caspase: 1) SfDronc efficiently cleaved synthetic initiator caspase substrates, but had very little activity against effector caspase substrates; 2) mutation of a predicted cleavage site at position D340 blocked autoprocessing of recombinant SfDronc and reduced enzyme activity by approximately 10-fold; 3) SfDronc cleaved the effector caspase Sf-caspase-1 at the expected cleavage site, resulting in Sf-caspase-1 activation; and 4) SfDronc was strongly inhibited by the baculovirus caspase inhibitor SpliP49, but not by the related protein AcP35. These results indicate that SfDronc is an initiator caspase involved in caspase-dependent apoptosis in S. frugiperda, and as such is likely to be responsible for the initiator caspase activity in S. frugiperda cells known as Sf-caspase-X.
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Affiliation(s)
- Ning Huang
- Molecular, Cellular and Developmental Biology Program, Division of Biology, Kansas State University, Manhattan, KS 66503
| | - Srgjan Civciristov
- Department of Biochemistry, La Trobe University, Bundoora 3086, Victoria, Australia
| | - Christine J. Hawkins
- Department of Biochemistry, La Trobe University, Bundoora 3086, Victoria, Australia
| | - Rollie J. Clem
- Molecular, Cellular and Developmental Biology Program, Division of Biology, Kansas State University, Manhattan, KS 66503
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Brand IL, Civciristov S, Taylor NL, Talbo GH, Pantaki-Eimany D, Levina V, Clem RJ, Perugini MA, Kvansakul M, Hawkins CJ. Caspase inhibitors of the P35 family are more active when purified from yeast than bacteria. PLoS One 2012; 7:e39248. [PMID: 22720082 PMCID: PMC3375223 DOI: 10.1371/journal.pone.0039248] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2012] [Accepted: 05/22/2012] [Indexed: 11/19/2022] Open
Abstract
Many insect viruses express caspase inhibitors of the P35 superfamily, which prevent defensive host apoptosis to enable viral propagation. The prototypical P35 family member, AcP35 from Autographa californica M nucleopolyhedrovirus, has been extensively studied. Bacterially purified AcP35 has been previously shown to inhibit caspases from insect, mammalian and nematode species. This inhibition occurs via a pseudosubstrate mechanism involving caspase-mediated cleavage of a "reactive site loop" within the P35 protein, which ultimately leaves cleaved P35 covalently bound to the caspase's active site. We observed that AcP35 purifed from Saccharomyces cerevisae inhibited caspase activity more efficiently than AcP35 purified from Escherichia coli. This differential potency was more dramatic for another P35 family member, MaviP35, which inhibited human caspase 3 almost 300-fold more potently when purified from yeast than bacteria. Biophysical assays revealed that MaviP35 proteins produced in bacteria and yeast had similar primary and secondary structures. However, bacterially produced MaviP35 possessed greater thermal stability and propensity to form higher order oligomers than its counterpart purified from yeast. Caspase 3 could process yeast-purified MaviP35, but failed to detectably cleave bacterially purified MaviP35. These data suggest that bacterially produced P35 proteins adopt subtly different conformations from their yeast-expressed counterparts, which hinder caspase access to the reactive site loop to reduce the potency of caspase inhibition, and promote aggregation. These data highlight the differential caspase inhibition by recombinant P35 proteins purified from different sources, and caution that analyses of bacterially produced P35 family members (and perhaps other types of proteins) may underestimate their activity.
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Affiliation(s)
- Ingo L. Brand
- Department of Biochemistry, La Trobe Institute for Molecular Science, La Trobe University, Bundoora, Victoria, Australia
| | - Srgjan Civciristov
- Department of Biochemistry, La Trobe Institute for Molecular Science, La Trobe University, Bundoora, Victoria, Australia
| | - Nicole L. Taylor
- Department of Biochemistry, La Trobe Institute for Molecular Science, La Trobe University, Bundoora, Victoria, Australia
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, Victoria, Australia
| | - Gert H. Talbo
- Department of Biochemistry, La Trobe Institute for Molecular Science, La Trobe University, Bundoora, Victoria, Australia
| | - Delara Pantaki-Eimany
- Department of Biochemistry, La Trobe Institute for Molecular Science, La Trobe University, Bundoora, Victoria, Australia
| | - Vita Levina
- Department of Biochemistry, La Trobe Institute for Molecular Science, La Trobe University, Bundoora, Victoria, Australia
| | - Rollie J. Clem
- Division of Biology, Kansas State University, Manhattan, Kansas, United States of America
| | - Matthew A. Perugini
- Department of Biochemistry, La Trobe Institute for Molecular Science, La Trobe University, Bundoora, Victoria, Australia
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, Victoria, Australia
| | - Marc Kvansakul
- Department of Biochemistry, La Trobe Institute for Molecular Science, La Trobe University, Bundoora, Victoria, Australia
| | - Christine J. Hawkins
- Department of Biochemistry, La Trobe Institute for Molecular Science, La Trobe University, Bundoora, Victoria, Australia
- Murdoch Children's Research Institute, Royal Children's Hospital, Parkville, Australia
- * E-mail:
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20
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Brand IL, Green MM, Civciristov S, Pantaki-Eimany D, George C, Gort TR, Huang N, Clem RJ, Hawkins CJ. Functional and biochemical characterization of the baculovirus caspase inhibitor MaviP35. Cell Death Dis 2011; 2:e242. [PMID: 22170098 PMCID: PMC3252740 DOI: 10.1038/cddis.2011.127] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [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: 11/24/2022]
Abstract
Many viruses express proteins which prevent the host cell death that their infection would otherwise provoke. Some insect viruses suppress host apoptosis through the expression of caspase inhibitors belonging to the P35 superfamily. Although a number of P35 relatives have been identified, Autographa californica (Ac) P35 and Spodoptera littoralis (Spli) P49 have been the most extensively characterized. AcP35 was found to inhibit caspases via a suicide substrate mechanism: the caspase cleaves AcP35 within its ‘reactive site loop' then becomes trapped, irreversibly bound to the cleaved inhibitor. The Maruca vitrata multiple nucleopolyhedrovirus encodes a P35 family member (MaviP35) that exhibits 81% identity to AcP35. We found that this relative shared with AcP35 the ability to inhibit mammalian and insect cell death. Caspase-mediated cleavage within the MaviP35 reactive site loop occurred at a sequence distinct from that in AcP35, and the inhibitory profiles of the two P35 relatives differed. MaviP35 potently inhibited human caspases 2 and 3, DCP-1, DRICE and CED-3 in vitro, but (in contrast to AcP35) only weakly suppressed the proteolytic activity of the initiator human caspases 8, 9 and 10. Although MaviP35 inhibited the AcP35-resistant caspase DRONC in yeast, and was sensitive to cleavage by DRONC in vitro, MaviP35 failed to inhibit the proteolytic activity of bacterially produced DRONC in vitro.
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Affiliation(s)
- I L Brand
- Department of Biochemistry, La Trobe University, Bundoora, Victoria, Australia
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21
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Abstract
Chemotherapy and radiotherapy commonly damage DNA and trigger p53-dependent apoptosis through intrinsic apoptotic pathways. Two unfortunate consequences of this mechanism are resistance due to blockade of p53 or intrinsic apoptosis pathways, and mutagenesis of non-malignant surviving cells which can impair cellular function or provoke second malignancies. Death ligand-based drugs, such as tumor necrosis factor-related apoptosis inducing ligand (TRAIL), stimulate extrinsic apoptotic signaling, and may overcome resistance to treatments that induce intrinsic apoptosis. As death receptor ligation does not damage DNA as a primary mechanism of pro-apoptotic action, we hypothesized that surviving cells would remain genetically unscathed, suggesting that death ligand-based therapies may avoid some of the adverse effects associated with traditional cancer treatments. Surprisingly, however, treatment with sub-lethal concentrations of TRAIL or FasL was mutagenic. Mutations arose in viable cells that contained active caspases, and overexpression of the caspase-8 inhibitor crmA or silencing of caspase-8 abolished TRAIL-mediated mutagenesis. Downregulation of the apoptotic nuclease caspase-activated DNAse (CAD)/DNA fragmentation factor 40 (DFF40) prevented the DNA damage associated with TRAIL treatment. Although death ligands do not need to damage DNA in order to induce apoptosis, surviving cells nevertheless incur DNA damage after treatment with these agents.
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Affiliation(s)
- M M Lovric
- Department of Biochemistry, La Trobe Institute for Molecular Sciences, La Trobe University, Bundoora, Victoria, Australia
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22
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Abstract
The caspases are an evolutionarily conserved family of cysteine proteases, with essential roles in apoptosis or inflammation. Caspase-2 was the second caspase to be cloned and it resembles the prototypical nematode caspase CED-3 more closely than any other mammalian protein. An absence of caspase-2-specific reagents and the subtle phenotype of caspase-2-deficient mice have hampered definition of the physiological role of caspase-2 and identification of factors regulating its activity. Although some data implicate caspase-2 in apoptotic pathways, a link with apoptosis has been less firmly established for caspase-2 than for some other caspases. Emerging evidence suggests that caspase-2 regulates the cell cycle and may act as a tumour suppressor. This article critically reviews the current state of knowledge regarding the biochemistry and biology of this controversial caspase.
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Affiliation(s)
- Tanja Kitevska
- Department of Biochemistry, La Trobe University, Bundoora, VIC 3086, Australia
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Ashley DM, Riffkin CD, Lovric MM, Mikeska T, Dobrovic A, Maxwell JA, Friedman HS, Drummond KJ, Kaye AH, Gan HK, Johns TG, Hawkins CJ. Erratum: In vitro sensitivity testing of minimally passaged and uncultured gliomas with TRAIL and/or chemotherapy drugs. Br J Cancer 2009. [PMCID: PMC2661787 DOI: 10.1038/sj.bjc.6604990] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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24
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Vince JE, Chau D, Callus B, Wong WWL, Hawkins CJ, Schneider P, McKinlay M, Benetatos CA, Condon SM, Chunduru SK, Yeoh G, Brink R, Vaux DL, Silke J. TWEAK-FN14 signaling induces lysosomal degradation of a cIAP1–TRAF2 complex to sensitize tumor cells to TNFα. J Exp Med 2008. [DOI: 10.1084/jem2058oia18] [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: 11/04/2022] Open
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25
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Vince JE, Chau D, Callus B, Wong WWL, Hawkins CJ, Schneider P, McKinlay M, Benetatos CA, Condon SM, Chunduru SK, Yeoh G, Brink R, Vaux DL, Silke J. TWEAK-FN14 signaling induces lysosomal degradation of a cIAP1-TRAF2 complex to sensitize tumor cells to TNFalpha. ACTA ACUST UNITED AC 2008; 182:171-84. [PMID: 18606850 PMCID: PMC2447903 DOI: 10.1083/jcb.200801010] [Citation(s) in RCA: 211] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Synthetic inhibitor of apoptosis (IAP) antagonists induce degradation of IAP proteins such as cellular IAP1 (cIAP1), activate nuclear factor κB (NF-κB) signaling, and sensitize cells to tumor necrosis factor α (TNFα). The physiological relevance of these discoveries to cIAP1 function remains undetermined. We show that upon ligand binding, the TNF superfamily receptor FN14 recruits a cIAP1–Tnf receptor-associated factor 2 (TRAF2) complex. Unlike IAP antagonists that cause rapid proteasomal degradation of cIAP1, signaling by FN14 promotes the lysosomal degradation of cIAP1–TRAF2 in a cIAP1-dependent manner. TNF-like weak inducer of apoptosis (TWEAK)/FN14 signaling nevertheless promotes the same noncanonical NF-κB signaling elicited by IAP antagonists and, in sensitive cells, the same autocrine TNFα-induced death occurs. TWEAK-induced loss of the cIAP1–TRAF2 complex sensitizes immortalized and minimally passaged tumor cells to TNFα-induced death, whereas primary cells remain resistant. Conversely, cIAP1–TRAF2 complex overexpression limits FN14 signaling and protects tumor cells from TWEAK-induced TNFα sensitization. Lysosomal degradation of cIAP1–TRAF2 by TWEAK/FN14 therefore critically alters the balance of life/death signals emanating from TNF-R1 in immortalized cells.
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Affiliation(s)
- James E Vince
- Department of Biochemistry, La Trobe University, Kingsbury Drive, Melbourne, VIC 3086, Australia
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26
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Scott FL, Fuchs GJ, Boyd SE, Denault JB, Hawkins CJ, Dequiedt F, Salvesen GS. Caspase-8 cleaves histone deacetylase 7 and abolishes its transcription repressor function. J Biol Chem 2008; 283:19499-510. [PMID: 18458084 DOI: 10.1074/jbc.m800331200] [Citation(s) in RCA: 40] [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: 02/05/2023] Open
Abstract
Caspase-8 is the initiator caspase of the extrinsic apoptosis pathway and also has a role in non-apoptotic physiologies. Identifying endogenous substrates for caspase-8 by using integrated bioinformatics and biological approaches is required to delineate the diverse roles of this caspase. We describe a number of novel putative caspase-8 substrates using the Prediction of Protease Specificity (PoPS) program, one of which is histone deacetylase 7 (HDAC7). HDAC7 is cleaved faster than any other caspase-8 substrate described to date. It is also cleaved in primary CD4+CD8+ thymocytes undergoing extrinsic apoptosis. By using naturally occurring caspase inhibitors that have evolved exquisite specificity at concentrations found within the cell, we could unequivocally assign the cleavage activity to caspase-8. Importantly, cleavage of HDAC7 alters its subcellular localization and abrogates its Nur77 repressor function. Thus we demonstrate a direct role for initiator caspase-mediated proteolysis in promoting gene transcription.
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Affiliation(s)
- Fiona L Scott
- Program in Apoptosis and Cell Death Research, Burnham Institute for Medical Research, La Jolla, California 92037, USA.
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27
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Westein SJ, Scott FL, Hawkins CJ. Analysis of the minimal specificity of CED-3 using a yeast transcriptional reporter system. Biochim Biophys Acta 2007; 1783:448-54. [PMID: 17996738 DOI: 10.1016/j.bbamcr.2007.10.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2007] [Revised: 09/28/2007] [Accepted: 10/04/2007] [Indexed: 10/22/2022]
Abstract
Determination of the substrate specificity of site-specific proteases helps define their physiological roles. We developed a yeast-based system for defining the minimal substrate specificity of site-specific proteases, within the context of a protein. Using this system, we characterized the P4-P1 substrate specificity of the nematode apoptotic caspase CED-3. Apart from an absolute requirement for aspartate at the P1 position, CED-3 is a relatively promiscuous caspase capable of cleaving substrates bearing many amino acids at P4-P2 sites.
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Affiliation(s)
- Sarah J Westein
- Department of Biochemistry, La Trobe University, Bundoora, Victoria, Australia
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Abstract
This study characterised the impact of active metazoan apoptotic proteases (caspases) on Saccharomyces cerevisiae viability. Expression of active caspase-3 or caspase-8 in yeast ruptured plasma and nuclear membranes and dramatically impaired clonogenic survival, but did not damage DNA. Deletion of the proposed yeast apoptosis regulators YCA1 or Aif1p did not affect the ability of human, insect or nematode caspases to kill yeast. These data indicate that expression of active metazoan caspases causes irreversible damage to yeast membranes and organelles, in a manner independent of YCA1 and Aif1p.
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Affiliation(s)
- M A Puryer
- Children's Cancer Centre, Royal Children's Hospital, Parkville, 3052, Australia
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29
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Verhagen AM, Kratina TK, Hawkins CJ, Silke J, Ekert PG, Vaux DL. Identification of mammalian mitochondrial proteins that interact with IAPs via N-terminal IAP binding motifs. Cell Death Differ 2006; 14:348-57. [PMID: 16794601 DOI: 10.1038/sj.cdd.4402001] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Direct IAP binding protein with low pI/second mitochondrial activator of caspases, HtrA2/Omi and GstPT/eRF3 are mammalian proteins that bind via N-terminal inhibitor of apoptosis protein (IAP) binding motifs (IBMs) to the baculoviral IAP repeat (BIR) domains of IAPs. These interactions can prevent IAPs from inhibiting caspases, or displace active caspases, thereby promoting cell death. We have identified several additional potential IAP antagonists, including glutamate dehydrogenase (GdH), Nipsnap 3 and 4, CLPX, leucine-rich pentatricopeptide repeat motif-containing protein and 3-hydroxyisobutyrate dehydrogenase. All are mitochondrial proteins from which N-terminal import sequences are removed generating N-terminal IBMs. Whereas most of these proteins have alanine at the N-terminal position, as observed for previously described antagonists, GdH has an N-terminal serine residue that is essential for X-linked IAP (XIAP) interaction. These newly described IAP binding proteins interact with XIAP mainly via BIR2, with binding eliminated or significantly reduced by a single point mutation (D214S) within this domain. Through this interaction, many are able to antagonise XIAP inhibition of caspase 3 in vitro.
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Affiliation(s)
- A M Verhagen
- The Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, Victoria 3050, Australia
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30
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Jabbour AM, Puryer MA, Yu JY, Lithgow T, Riffkin CD, Ashley DM, Vaux DL, Ekert PG, Hawkins CJ. Human Bcl-2 cannot directly inhibit the Caenorhabditis elegans Apaf-1 homologue CED-4, but can interact with EGL-1. J Cell Sci 2006; 119:2572-82. [PMID: 16735440 DOI: 10.1242/jcs.02985] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Although the anti-apoptotic activity of Bcl-2 has been extensively studied, its mode of action is still incompletely understood. In the nematode Caenorhabditis elegans, 131 of 1090 somatic cells undergo programmed cell death during development. Transgenic expression of human Bcl-2 reduced cell death during nematode development, and partially complemented mutation of ced-9, indicating that Bcl-2 can functionally interact with the nematode cell death machinery. Identification of the nematode target(s) of Bcl-2 inhibition would help clarify the mechanism by which Bcl-2 suppresses apoptosis in mammalian cells. Exploiting yeast-based systems and biochemical assays, we analysed the ability of Bcl-2 to interact with and regulate the activity of nematode apoptosis proteins. Unlike CED-9, Bcl-2 could not directly associate with the caspase-activating adaptor protein CED-4, nor could it inhibit CED-4-dependent yeast death. By contrast, Bcl-2 could bind the C. elegans pro-apoptotic BH3-only Bcl-2 family member EGL-1. These data prompt us to hypothesise that Bcl-2 might suppress nematode cell death by preventing EGL-1 from antagonising CED-9, rather than by inhibiting CED-4.
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Affiliation(s)
- Anissa M Jabbour
- Children's Cancer Centre, Royal Children's Hospital, Parkville 3052, Australia
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31
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Li S, Ferguson MJ, Hawkins CJ, Smith C, Elwood NJ. Human telomerase reverse transcriptase protects hematopoietic progenitor TF-1 cells from death and quiescence induced by cytokine withdrawal. Leukemia 2006; 20:1270-8. [PMID: 16673017 DOI: 10.1038/sj.leu.2404251] [Citation(s) in RCA: 14] [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: 12/31/2022]
Abstract
Telomerase is a complex ribonucleoprotein enzyme that exhibits elevated activity in the majority of cases of human leukemia. We have previously shown that retroviral expression of the catalytic subunit of telomerase, human telomerase reverse transcriptase (hTERT), in human cord blood CD34+ cells leads to an enhanced survival of mature hematopoietic cells. The mechanism for this pro-survival effect is not known. Here, we show that telomerase may play a role in leukemogenesis as a survival factor, independent of its role in maintaining telomere length. Retroviral expression of hTERT in the cytokine-dependent, human hematopoietic progenitor cell line, TF-1, resulted in the survival of cells following the withdrawal of cytokine, with protection from apoptosis, but did not promote unlimited replicative potential. This hTERT-mediated effect on cell survival does not involve Bcl-2 family members, results in accumulation of cells in G1 and appears to operate via autocrine expression of IL-3 and activation of the p53/p21 pathway. Survival in the absence of cytokine stimulation was also observed following retroviral expression of hTERT in normal cord blood CD34+ cells. This study demonstrates a novel pro-survival role for hTERT and may have important implications for the role of hTERT in the pathogenesis of leukemia and drug resistance.
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Affiliation(s)
- S Li
- Children's Cancer Centre, Murdoch Children's Research Institute, University of Melbourne, Parkville, Victoria, Australia
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32
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Abstract
Caspases are a conserved family of cysteine proteases. They play diverse roles in inflammatory responses and apoptotic pathways. Among the caspases is a subgroup whose primary function is to initiate apoptosis. Within their long prodomains, caspases-2, -9 and -12 contain a caspase activation and recruitment domain while caspases-8 and -10 bear death effector domains. Activation follows the recruitment of the procaspase molecule via the prodomain to a high molecular mass complex. Despite sharing some common features, other aspects of the biochemistry, substrate specificity, regulation and signaling mechanisms differ between initiator apoptotic caspases. Defects in expression or activity of these caspases are related to certain pathological conditions including neurodegenerative disorders, autoimmune diseases and cancer.
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Affiliation(s)
- Po-ki Ho
- Murdoch Children's Research Institute, Parkville, Victoria, Australia
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33
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Abstract
BACKGROUND Better treatments are required urgently for patients with malignant glioma, which currently is incurable. Death ligands, such as tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), may offer promise for the treatment high-grade glioma if such ligands induce apoptotic signaling in vivo in glioma cells. Caspase 8 is required for death ligand signaling, and its levels may influence the sensitivity of glioma cells to death ligands. It also may act as a tumor suppressor protein. The authors analyzed caspase 8 expression levels in ex vivo glioma specimens and explored potential mechanisms of its regulation. METHODS Eleven glioblastomas, 5 anaplastic astrocytomas, and 3 low-grade astrocytomas were studied. The levels of caspase 8, caspase 10, cellular FLICE inhibitory protein (c-FLIP), and signal transducer and activator of transcription (STAT)-1 were assayed using quantitative immunoblotting. Caspase 8 mRNA was measured by Northern blot analysis. The methylation status of the caspase 8 gene was determined by bisulfate modification of genomic DNA, cloning, and sequencing. Statistical analyses were performed using nonparametric (Spearman) correlations. RESULTS Some ex vivo glioma samples lacked detectable caspase 8, with many expressing barely detectable levels. No tumors expressed significant amounts of caspase 10 or c-FLIP. A strong association was found between caspase 8 mRNA and protein levels. Neither expression of the transcription factor STAT-1 nor caspase 8 gene methylation correlated with caspase 8 levels. CONCLUSIONS The absence of caspase 8 protein in many resected glioma samples implied that many patients with glioma may not benefit from death ligand-based treatments, unless caspase 8 (or caspase 10) protein expression can be elevated. Demethylating agents are unlikely to boost caspase 8 levels in glioma cells, but treatments that increase caspase 8 mRNA levels may up-regulate expression of the protein.
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Affiliation(s)
- David M Ashley
- Murdoch Children's Research Institute, Parkville, Australia
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34
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Jabbour AM, Ho PK, Puryer MA, Ashley DM, Ekert PG, Hawkins CJ. The Caenorhabditis elegans CED-9 protein does not directly inhibit the caspase CED-3, in vitro nor in yeast. Cell Death Differ 2005; 11:1309-16. [PMID: 15543163 DOI: 10.1038/sj.cdd.4401501] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
A genetically defined pathway orchestrates the removal of 131 of the 1090 somatic cells generated during the development of the hermaphrodite nematode Caenorhabditis elegans. Regulation of apoptosis is highly evolutionarily conserved and the nematode cell death pathway is a valuable model for studying mammalian apoptotic pathways, the dysregulation of which can contribute to numerous diseases. The nematode caspase CED-3 is ultimately responsible for the destruction of worm cells in response to apoptotic signals, but it must first be activated by CED-4. CED-9 inhibits programmed cell death and considerable data have demonstrated that CED-9 can directly bind and inhibit CED-4. However, it has been suggested that CED-9 may also directly inhibit CED-3. In this study, we used a yeast-based system and biochemical approaches to explore this second potential mechanism of action. While we confirmed the ability of CED-9 to inhibit CED-4, our data argue that CED-9 can not directly inhibit CED-3.
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Affiliation(s)
- A M Jabbour
- Murdoch Children's Research Institute, Parkville 3052, Australia
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Abstract
Caspases are a family of cysteine proteases with roles in cytokine maturation or apoptosis. Caspase-2 was the first pro-apoptotic caspase identified, but its functions in apoptotic signal transduction are still being elucidated. This study examined the regulation of the activity of caspase-2 using recombinant proteins and a yeast-based system. Our data suggest that for human caspase-2 to be active its large and small subunits must be separated. For maximal activity its prodomain must also be removed. Consistent with its proposed identity as an upstream caspase, caspase-2 could provoke the activation of caspase-7. Caspase-2 was not subject to inhibition by members of the IAP family of apoptosis inhibitors.
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Affiliation(s)
- Po-Ki Ho
- Murdoch Children's Research Institute, Parkville, Australia
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36
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Burri L, Strahm Y, Hawkins CJ, Gentle IE, Puryer MA, Verhagen A, Callus B, Vaux D, Lithgow T. Mature DIABLO/Smac is produced by the IMP protease complex on the mitochondrial inner membrane. Mol Biol Cell 2005; 16:2926-33. [PMID: 15814844 PMCID: PMC1142436 DOI: 10.1091/mbc.e04-12-1086] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
DIABLO/Smac is a mitochondrial protein that can promote apoptosis by promoting the release and activation of caspases. To do so, DIABLO/Smac must first be processed by a mitochondrial protease and then released into the cytosol, and we show this in an intact cellular system. We propose that the precursor form of DIABLO/Smac enters the mitochondria through a stop-transfer pathway and is processed to its active form by the inner membrane peptidase (IMP) complex. Catalytic subunits of the mammalian IMP complex were identified based on sequence conservation and functional complementation, and the novel sequence motif RX(5)P in Imp1 and NX(5)S in Imp2 distinguish the two catalytic subunits. DIABLO/Smac is one of only a few specific proteins identified as substrates for the IMP complex in the mitochondrial intermembrane space.
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Affiliation(s)
- Lena Burri
- Russell Grimwade School of Biochemistry and Molecular Biology, University of Melbourne, Parkville, VIC 3010, Australia
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Steel R, Doherty JP, Buzzard K, Clemons N, Hawkins CJ, Anderson RL. Hsp72 inhibits apoptosis upstream of the mitochondria and not through interactions with Apaf-1. J Biol Chem 2004; 279:51490-9. [PMID: 15371421 DOI: 10.1074/jbc.m401314200] [Citation(s) in RCA: 103] [Impact Index Per Article: 5.2] [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: 11/06/2022] Open
Abstract
Hsp72 protects cells against apoptosis in response to various stresses. By simultaneously measuring cytochrome c localization and nuclear morphology in mouse embryo fibroblasts, we have shown that Hsp72 blocks cytochrome c release from mitochondria in response to cytotoxic stress and that permeabilization of the outer mitochondrial membrane is the critical point in deciding the fate of the cell. Hsp72 did not inhibit apoptosis in mouse embryo fibroblasts once cytochrome c had been released from the mitochondria. Recent reports have claimed that Hsp72 can prevent caspase activation by inhibiting the oligomerization of Apaf-1 in the presence of cytochrome c and dATP. We now show that this apparent function of recombinant Hsp72 is due to the presence of salt in the Hsp72 preparation and that the same response can be achieved by the addition of heat-denatured Hsp72 in the same high salt buffer or by the high salt buffer alone. Hsp72 expressed in a range of different cell lines had no inhibitory effect on cytochrome c-stimulated caspase activity of cytosolic extracts. We conclude that the protective effect of Hsp72 occurs upstream of the mitochondria and not through the inhibition of the apoptosome.
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Affiliation(s)
- Rohan Steel
- Peter MacCallum Cancer Centre, A'Beckett St., Locked Bag #1, Melbourne, Victoria 8006, Australia
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Ekert PG, Read SH, Silke J, Marsden VS, Kaufmann H, Hawkins CJ, Gerl R, Kumar S, Vaux DL. Apaf-1 and caspase-9 accelerate apoptosis, but do not determine whether factor-deprived or drug-treated cells die. ACTA ACUST UNITED AC 2004; 165:835-42. [PMID: 15210730 PMCID: PMC2172390 DOI: 10.1083/jcb.200312031] [Citation(s) in RCA: 144] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Apoptosis after growth factor withdrawal or drug treatment is associated with mitochondrial cytochrome c release and activation of Apaf-1 and caspase-9. To determine whether loss of Apaf-1, caspase-2, and caspase-9 prevented death of factor-starved cells, allowing them to proliferate when growth factor was returned, we generated IL-3–dependent myeloid lines from gene-deleted mice. Long after growth factor removal, cells lacking Apaf-1, caspase-9 or both caspase-9 and caspase-2 appeared healthy, retained intact plasma membranes, and did not expose phosphatidylserine. However, release of cytochrome c still occurred, and they failed to form clones when IL-3 was restored. Cells lacking caspase-2 alone had no survival advantage. Therefore, Apaf-1, caspase-2, and caspase-9 are not required for programmed cell death of factor-dependent cells, but merely affect its rate. In contrast, transfection with Bcl-2 provided long-term, clonogenic protection, and could act independently of the apoptosome. Unlike expression of Bcl-2, loss of Apaf-1, caspase-2, or caspase-9 would therefore be unlikely to enhance the survival of cancer cells.
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Affiliation(s)
- Paul G Ekert
- The Walter and Eliza Hall Institute for Medical Research, 1G Royal Parade, Parkville, Victoria 3050, Australia.
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39
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Knight MJ, Riffkin CD, Ekert PG, Ashley DM, Hawkins CJ. Caspase-8 levels affect necessity for mitochondrial amplification in death ligand-induced glioma cell apoptosis. Mol Carcinog 2004; 39:173-82. [PMID: 14991747 DOI: 10.1002/mc.20011] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Fifty percent of high-grade glioma patients die within a year of diagnosis and less than two percent survive five years postdiagnosis. Elucidating apoptosis signaling pathways may assist in designing better adjuvant therapies. Preliminary characterizations suggested that glioma cells may either employ mitochondrial-independent or -dependent death receptor-induced apoptotic pathways, characteristic of cells termed type I and type II, respectively. In the present study, we generated panels of clonal transfectants overexpressing various levels of Bcl-2, in two parental glioma cell lines. These cells were used to explore molecular factors determining the necessity for mitochondrial amplification of death receptor signaling. Moderate Bcl-2 expression was sufficient to render one glioma cell line (D270) resistant to apoptosis induced by Fas ligand or TRAIL, consistent with these cells being type II. However, expression of even very high levels of Bcl-2 in a second line (D645) did not affect death ligand sensitivity, indicative of a type I phenotype. D270 cells expressed much less caspase-8 protein than D645 cells. Enforced overexpression of caspase-8 (or cytoplasmic Diablo/Smac) in D270 cells overcame Bcl-2 inhibition of death ligand-induced apoptosis, converting them from type II to type I. This indicates that caspase-8 levels can influence the requirement for mitochondrial involvement in death receptor apoptotic signaling in glioma cells.
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Affiliation(s)
- Melissa J Knight
- Department of Haematology and Oncology, Royal Children's Hospital, Parkville, Victoria, Australia
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40
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Abstract
Encouragingly, some types of cancer can now be considered treatable, with patients reasonably expecting their disease to be cured. Chemotherapy and radiation therapy are effective against these cancers because they activate the so-called intrinsic apoptosis pathways within the cancer cells. Unfortunately currently available treatments are only effective against a subset of tumor types. In contrast, other cancers, such as malignant glioma, typically do not respond to currently available therapies. Some of this resistance can be attributed to these tumor cells failing to undergo apoptosis upon anticancer treatment. Recently, considerable research attention has focused on triggering apoptosis in chemotherapy- and radiation-therapy-resistant cancer cells via an alternative route-the "extrinsic" pathway, as a means of bypassing this block in apoptosis. Binding of members of the tumor necrosis factor-alpha (TNF-alpha) family of death ligands to their receptors on the cell surface triggers this pathway. Death ligands can kill some cancer cells that are resistant to the apoptotic pathway triggered by conventional anticancer treatments. Some death ligands, such as TNF-alpha and FasL, cause unacceptable toxicity to normal cells and are therefore not suitable anticancer agents. However another death ligand, TNF-related apoptosis-inducing ligand (TRAIL)/Apo-2L, and antibodies that emulate its actions, show greater promise as candidate anticancer drugs because they have negligible effects on normal cells. This review will discuss the ability of TRAIL to induce apoptosis in malignant glioma cells and the potential clinical applications of TRAIL-based agents for glioma treatment.
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Affiliation(s)
- Christine J Hawkins
- Murdoch Children's Research Institute Department of Haematology and Oncology, Royal Children's Hospital Department of Paediatrics, University of Melbourne Parkville, Victoria 3052, Australia
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41
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Jabbour AM, Ekert PG, Coulson EJ, Knight MJ, Ashley DM, Hawkins CJ. The p35 relative, p49, inhibits mammalian and Drosophila caspases including DRONC and protects against apoptosis. Cell Death Differ 2002; 9:1311-20. [PMID: 12478468 DOI: 10.1038/sj.cdd.4401135] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2002] [Revised: 08/07/2002] [Accepted: 08/20/2002] [Indexed: 11/08/2022] Open
Abstract
This study characterized the ability of a new member of the p35 family, p49, to inhibit a number of mammalian and insect caspases. p49 blocked apoptosis triggered by treatment with Fas ligand (FasL), Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) or ultraviolet (UV) radiation but provided negligible protection against apoptosis induced by the chemotherapeutic drug cisplatin. The caspase cleavage site in p49 was determined, and mutation of the P1 residue of this site abolished the ability of p49 to inhibit caspases, implying that p49 inhibits caspases through an analogous suicide-substrate mechanism to p35. Unlike p35, p49 inhibited the upstream insect caspase DRONC.
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Affiliation(s)
- A M Jabbour
- Department of Haematology and Oncology, Royal Children's Hospital, Parkville 3052, Australia
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42
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Silke J, Hawkins CJ, Ekert PG, Chew J, Day CL, Pakusch M, Verhagen AM, Vaux DL. The anti-apoptotic activity of XIAP is retained upon mutation of both the caspase 3- and caspase 9-interacting sites. J Cell Biol 2002; 157:115-24. [PMID: 11927604 PMCID: PMC2173256 DOI: 10.1083/jcb.200108085] [Citation(s) in RCA: 105] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The X-linked mammalian inhibitor of apoptosis protein (XIAP) has been shown to bind several partners. These partners include caspase 3, caspase 9, DIABLO/Smac, HtrA2/Omi, TAB1, the bone morphogenetic protein receptor, and a presumptive E2 ubiquitin-conjugating enzyme. In addition, we show here that XIAP can bind to itself. To determine which of these interactions are required for it to inhibit apoptosis, we generated point mutant XIAP proteins and correlated their ability to bind other proteins with their ability to inhibit apoptosis. partial differential RING point mutants of XIAP were as competent as their full-length counterparts in inhibiting apoptosis, although impaired in their ability to oligomerize with full-length XIAP. Triple point mutants, unable to bind caspase 9, caspase 3, and DIABLO/HtrA2/Omi, were completely ineffectual in inhibiting apoptosis. However, point mutants that had lost the ability to inhibit caspase 9 and caspase 3 but retained the ability to inhibit DIABLO were still able to inhibit apoptosis, demonstrating that IAP antagonism is required for apoptosis to proceed following UV irradiation.
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Affiliation(s)
- John Silke
- The Walter and Eliza Hall Institute of Medical Research, Victoria 3050, Australia.
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43
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Riffkin CD, Gray AZ, Hawkins CJ, Chow CW, Ashley DM. Ex vivo pediatric brain tumors express Fas (CD95) and FasL (CD95L) and are resistant to apoptosis induction. Neuro Oncol 2001; 3:229-40. [PMID: 11584892 PMCID: PMC1920621 DOI: 10.1093/neuonc/3.4.229] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Fas (APO-1/CD95/TNFRSF6) is a member of the tumor necrosis/nerve growth factor receptor family that signals apoptotic cell death in sensitive cells. Expression of Fas and its agonistic ligand (FasL/TNFSF6) was investigated in ex vivo pediatric brain tumor specimens of various histologic types. Fas expression was identified in all of the 18 tumors analyzed by flow cytometry and immunohistochemistry. FasL expression was identified in most of the 13 tumors analyzed by both Western analysis and immunohistochemistry. Nine of these tumor specimens were treated with either the agonistic anti-Fas antibody (APO-1) in combination with protein A or FasL in short-term cytotoxicity assays. Sensitivity to apoptosis induced by the topoisomerase II inhibitor, etoposide, was also assessed. Despite the presence of Fas, all the specimens analyzed demonstrated a high degree of resistance to Fas-mediated apoptosis. These 9 specimens also showed a high degree of resistance to etoposide. Only 2 of the 9 specimens were susceptible to etoposide-induced cell death, whereas only 3 were sensitive to Fas-mediated apoptosis. One brain tumor was sensitive to both Fas ligation and etoposide treatment. This contrasted with the high degree of susceptibility to both etoposide- and Fas-induced apoptosis observed in the reference Jurkat cell line. The results suggest that Fas expression may be a general feature of tumors of the CNS and that a significant degree of resistance to Fas-mediated apoptosis may exist in ex vivo pediatric brain tumor specimens.
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Affiliation(s)
- C D Riffkin
- Department of Hematology and Oncology, Royal Children's Hospital, Melbourne, Victoria, Australia
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44
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Hawkins CJ, Silke J, Verhagen AM, Foster R, Ekert PG, Ashley DM. Analysis of candidate antagonists of IAP-mediated caspase inhibition using yeast reconstituted with the mammalian Apaf-1-activated apoptosis mechanism. Apoptosis 2001; 6:331-8. [PMID: 11483856 DOI: 10.1023/a:1011329917895] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
We have reconstituted the Apaf-1-activated apoptosis mechanism in Sacchromyces cerevisiae such that the presence of a constitutively active form of Apaf-1 together with both Caspase-9 and Caspase-3 results in yeast death. This system is a good model of the Apaf-1-activated pathway in mammalian cells: MIHA (XIAP/hILP), and to a lesser degree MIHB (c-IAP1/HIAP2) and MIHC (c-IAP-2/HIAP1) can inhibit caspases in this system, and protection by IAPs (inhibitor of apoptosis) can be abrogated by coexpression of the Drosophila pro-apoptotic proteins HID and GRIM or the mammalian protein DIABLO/Smac. Using this system we demonstrate that unlike DIABLO/Smac, other proteins which interact with mammalian IAPs (TAB-1, Zap-1, Traf-1 and Traf-2) do not act to antagonise IAP- mediated caspase inhibition.
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Affiliation(s)
- C J Hawkins
- Department of Haematology and Oncology, Murdoch Children's Research Institute, Royal Children's Hospital, Flemington Road, Parkville 3052, Australia.
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45
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Knight MJ, Riffkin CD, Muscat AM, Ashley DM, Hawkins CJ. Analysis of FasL and TRAIL induced apoptosis pathways in glioma cells. Oncogene 2001; 20:5789-98. [PMID: 11593384 DOI: 10.1038/sj.onc.1204810] [Citation(s) in RCA: 89] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2001] [Revised: 06/22/2001] [Accepted: 07/05/2001] [Indexed: 01/08/2023]
Abstract
FasL and TNF-related apoptosis-inducing ligand (TRAIL) belong to a subgroup of the TNF superfamily which induce apoptosis by binding to their death domain containing receptors. In the present study we have utilized a panel of seven cell lines derived from human malignant gliomas to characterize molecular pathways through which FasL and TRAIL induce apoptosis in sensitive glioma cells and the mechanisms of resistance in cell lines which survive the death stimuli. Our findings indicate that FADD and Caspase-8 are essential for FasL and TRAIL mediated apoptosis in glioma cells. One sensitive cell line (D270) can be protected from FasL and TRAIL induced death by anti-apoptotic Bcl-2 family members while another (D645) cannot, implying that these lines may represent glioma examples of type II and type I cells respectively. For the first time we demonstrate resistance to FasL but not to TRAIL within the one glioma cell line. Furthermore, we report distinct mechanisms of resistance within different glioma lines, including downregulation of Caspase-8 in U373MG. Cycloheximide sensitized four of the resistant cell lines suggesting the presence of labile inhibitors. None of the known apoptosis inhibitors examined accounted for the observed resistance, suggesting novel inhibitors may exist in glioma cells.
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Affiliation(s)
- M J Knight
- Department of Haematology and Oncology, Royal Children's Hospital, Parkville, Victoria, Australia 3052
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46
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Silke J, Ekert PG, Day CL, Hawkins CJ, Baca M, Chew J, Pakusch M, Verhagen AM, Vaux DL. Direct inhibition of caspase 3 is dispensable for the anti-apoptotic activity of XIAP. EMBO J 2001; 20:3114-23. [PMID: 11406588 PMCID: PMC150202 DOI: 10.1093/emboj/20.12.3114] [Citation(s) in RCA: 92] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
XIAP is a mammalian inhibitor of apoptosis protein (IAP). To determine residues within the second baculoviral IAP repeat (BIR2) required for inhibition of caspase 3, we screened a library of BIR2 mutants for loss of the ability to inhibit caspase 3 toxicity in the yeast Schizosaccharomyces pombe. Four of the mutations, not predicted to affect the structure of the BIR fold, clustered together on the N-terminal region that flanks BIR2, suggesting that this is a site of interaction with caspase 3. Introduction of these mutations into full-length XIAP reduced caspase 3 inhibitory activity up to 500-fold, but did not affect its ability to inhibit caspase 9 or interact with the IAP antagonist DIABLO. Furthermore, these mutants retained full ability to inhibit apoptosis in transfected cells, demonstrating that although XIAP is able to inhibit caspase 3, this activity is dispensable for inhibition of apoptosis by XIAP in vivo.
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Affiliation(s)
- John Silke
- The Walter and Eliza Hall Institute of Medical Research, Post Office Royal Melbourne Hospital, VIC 3050, Department of Haematology and Oncology, Royal Children’s Hospital, Flemington Road, Parkville 3052, Australia and Institute of Molecular BioSciences, Massey University, Private Bag 11222, Palmerston North, New Zealand Corresponding author e-mail:
| | - Paul G. Ekert
- The Walter and Eliza Hall Institute of Medical Research, Post Office Royal Melbourne Hospital, VIC 3050, Department of Haematology and Oncology, Royal Children’s Hospital, Flemington Road, Parkville 3052, Australia and Institute of Molecular BioSciences, Massey University, Private Bag 11222, Palmerston North, New Zealand Corresponding author e-mail:
| | - Catherine L. Day
- The Walter and Eliza Hall Institute of Medical Research, Post Office Royal Melbourne Hospital, VIC 3050, Department of Haematology and Oncology, Royal Children’s Hospital, Flemington Road, Parkville 3052, Australia and Institute of Molecular BioSciences, Massey University, Private Bag 11222, Palmerston North, New Zealand Corresponding author e-mail:
| | - Christine J. Hawkins
- The Walter and Eliza Hall Institute of Medical Research, Post Office Royal Melbourne Hospital, VIC 3050, Department of Haematology and Oncology, Royal Children’s Hospital, Flemington Road, Parkville 3052, Australia and Institute of Molecular BioSciences, Massey University, Private Bag 11222, Palmerston North, New Zealand Corresponding author e-mail:
| | - Manuel Baca
- The Walter and Eliza Hall Institute of Medical Research, Post Office Royal Melbourne Hospital, VIC 3050, Department of Haematology and Oncology, Royal Children’s Hospital, Flemington Road, Parkville 3052, Australia and Institute of Molecular BioSciences, Massey University, Private Bag 11222, Palmerston North, New Zealand Corresponding author e-mail:
| | - Joanne Chew
- The Walter and Eliza Hall Institute of Medical Research, Post Office Royal Melbourne Hospital, VIC 3050, Department of Haematology and Oncology, Royal Children’s Hospital, Flemington Road, Parkville 3052, Australia and Institute of Molecular BioSciences, Massey University, Private Bag 11222, Palmerston North, New Zealand Corresponding author e-mail:
| | - Miha Pakusch
- The Walter and Eliza Hall Institute of Medical Research, Post Office Royal Melbourne Hospital, VIC 3050, Department of Haematology and Oncology, Royal Children’s Hospital, Flemington Road, Parkville 3052, Australia and Institute of Molecular BioSciences, Massey University, Private Bag 11222, Palmerston North, New Zealand Corresponding author e-mail:
| | - Anne M. Verhagen
- The Walter and Eliza Hall Institute of Medical Research, Post Office Royal Melbourne Hospital, VIC 3050, Department of Haematology and Oncology, Royal Children’s Hospital, Flemington Road, Parkville 3052, Australia and Institute of Molecular BioSciences, Massey University, Private Bag 11222, Palmerston North, New Zealand Corresponding author e-mail:
| | - David L. Vaux
- The Walter and Eliza Hall Institute of Medical Research, Post Office Royal Melbourne Hospital, VIC 3050, Department of Haematology and Oncology, Royal Children’s Hospital, Flemington Road, Parkville 3052, Australia and Institute of Molecular BioSciences, Massey University, Private Bag 11222, Palmerston North, New Zealand Corresponding author e-mail:
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47
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Affiliation(s)
- C J Hawkins
- Department of Haematology and Oncology, Royal Children's Hospital, Parkville, VIC, Australia
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48
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Abstract
MIHA is an inhibitor of apoptosis protein (IAP) that can inhibit cell death by direct interaction with caspases, the effector proteases of apoptosis. DIABLO is a mammalian protein that can bind to IAPs and antagonize their antiapoptotic effect, a function analogous to that of the proapoptotic Drosophila molecules, Grim, Reaper, and HID. Here, we show that after UV radiation, MIHA prevented apoptosis by inhibiting caspase 9 and caspase 3 activation. Unlike Bcl-2, MIHA functioned after release of cytochrome c and DIABLO from the mitochondria and was able to bind to both processed caspase 9 and processed caspase 3 to prevent feedback activation of their zymogen forms. Once released into the cytosol, DIABLO bound to MIHA and disrupted its association with processed caspase 9, thereby allowing caspase 9 to activate caspase 3, resulting in apoptosis.
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Affiliation(s)
- Paul G. Ekert
- The Walter and Eliza Hall Institute, The Royal Melbourne Hospital, Victoria 3050, Australia
- Murdoch Children's Research Institute, Royal Children's Hospital, Parkville 3052, Australia
| | - John Silke
- The Walter and Eliza Hall Institute, The Royal Melbourne Hospital, Victoria 3050, Australia
| | - Christine J. Hawkins
- Department of Haematology and Oncology, Royal Children's Hospital, Parkville 3052, Australia
| | - Anne M. Verhagen
- The Walter and Eliza Hall Institute, The Royal Melbourne Hospital, Victoria 3050, Australia
| | - David L. Vaux
- The Walter and Eliza Hall Institute, The Royal Melbourne Hospital, Victoria 3050, Australia
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49
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Hawkins CJ, Yoo SJ, Peterson EP, Wang SL, Vernooy SY, Hay BA. The Drosophila caspase DRONC cleaves following glutamate or aspartate and is regulated by DIAP1, HID, and GRIM. J Biol Chem 2000; 275:27084-93. [PMID: 10825159 DOI: 10.1074/jbc.m000869200] [Citation(s) in RCA: 81] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The caspase family of cysteine proteases plays important roles in bringing about apoptotic cell death. All caspases studied to date cleave substrates COOH-terminal to an aspartate. Here we show that the Drosophila caspase DRONC cleaves COOH-terminal to glutamate as well as aspartate. DRONC autoprocesses itself following a glutamate residue, but processes a second caspase, drICE, following an aspartate. DRONC prefers tetrapeptide substrates in which aliphatic amino acids are present at the P2 position, and the P1 residue can be either aspartate or glutamate. Expression of a dominant negative form of DRONC blocks cell death induced by the Drosophila cell death activators reaper, hid, and grim, and DRONC overexpression in flies promotes cell death. Furthermore, the Drosophila cell death inhibitor DIAP1 inhibits DRONC activity in yeast, and DIAP1's ability to inhibit DRONC-dependent yeast cell death is suppressed by HID and GRIM. These observations suggest that DRONC acts to promote cell death. However, DRONC activity is not suppressed by the caspase inhibitor and cell death suppressor baculovirus p35. We discuss possible models for DRONC function as a cell death inhibitor.
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Affiliation(s)
- C J Hawkins
- Division of Biology, MC 156-29, Pasadena, California 91125, USA
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50
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Abstract
Drosophila Reaper (RPR), Head Involution Defective (HID), and GRIM induce caspase-dependent cell death and physically interact with the cell death inhibitor DIAP1. Here we show that HID blocks DIAP1's ability to inhibit caspase activity and provide evidence suggesting that RPR and GRIM can act similarly. Based on these results, we propose that RPR, HID, and GRIM promote apoptosis by disrupting productive IAP-caspase interactions and that DIAP1 is required to block apoptosis-inducing caspase activity. Supporting this hypothesis, we show that elimination of DIAP1 function results in global early embryonic cell death and a large increase in DIAP1-inhibitable caspase activity and that DIAP1 is still required for cell survival when expression of rpr, hid, and grim is eliminated.
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Affiliation(s)
- S L Wang
- Division of Biology MC 156-29, California Institute of Technology, Pasadena 91125, USA
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