301
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N-(1-pyrenyl) maleimide induces bak oligomerization and mitochondrial dysfunction in Jurkat Cells. BIOMED RESEARCH INTERNATIONAL 2015; 2015:798489. [PMID: 25632401 PMCID: PMC4302375 DOI: 10.1155/2015/798489] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/10/2014] [Revised: 12/20/2014] [Accepted: 12/20/2014] [Indexed: 11/26/2022]
Abstract
N-(1-pyrenyl) maleimide (NPM) is a fluorescent reagent that is frequently used as a derivatization agent for the detection of thio-containing compounds. NPM has been shown to display a great differential cytotoxicity against hematopoietic cancer cells. In this study, the molecular mechanism by which NPM induces apoptosis was examined. Here, we show that treatment of Jurkat cells with NPM leads to Bak oligomerization, loss of mitochondrial membrane potential (Δψm), and release of cytochrome C from mitochondria to cytosol. Induction of Bak oligomerization appears to play a critical role in NPM-induced apoptosis, as downregulation of Bak by shRNA significantly prevented NPM-induced apoptosis. Inhibition of caspase 8 by Z-IETD-FMK and/or depletion of Bid did not affect NPM-induced oligomerization of Bak. Taken together, these results suggest that NPM-induced apoptosis is mediated through a pathway that is independent of caspase-8 activation.
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302
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Suppression of epithelial-mesenchymal transition and apoptotic pathways by miR-294/302 family synergistically blocks let-7-induced silencing of self-renewal in embryonic stem cells. Cell Death Differ 2014; 22:1158-69. [PMID: 25501598 PMCID: PMC4572863 DOI: 10.1038/cdd.2014.205] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2014] [Revised: 10/27/2014] [Accepted: 11/03/2014] [Indexed: 01/01/2023] Open
Abstract
The embryonic stem cell (ESC)-enriched miR-294/302 family and the somatic cell-enriched let-7 family stabilizes the self-renewing and differentiated cell fates, respectively. The mechanisms underlying these processes remain unknown. Here we show that among many pathways regulated by miR-294/302, the combinatorial suppression of epithelial–mesenchymal transition (EMT) and apoptotic pathways is sufficient in maintaining the self-renewal of ESCs. The silencing of ESC self-renewal by let-7 was accompanied by the upregulation of several EMT regulators and the induction of apoptosis. The ectopic activation of either EMT or apoptotic program is sufficient in silencing ESC self-renewal. However, only combined but not separate suppression of the two programs inhibited the silencing of ESC self-renewal by let-7 and several other differentiation-inducing miRNAs. These findings demonstrate that combined repression of the EMT and apoptotic pathways by miR-294/302 imposes a synergistic barrier to the silencing of ESC self-renewal, supporting a model whereby miRNAs regulate complicated cellular processes through synergistic repression of multiple targets or pathways.
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303
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Mehta N, Taylor J, Quilty D, Barry M. Ectromelia virus encodes an anti-apoptotic protein that regulates cell death. Virology 2014; 475:74-87. [PMID: 25462348 DOI: 10.1016/j.virol.2014.10.023] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2014] [Revised: 10/21/2014] [Accepted: 10/23/2014] [Indexed: 10/24/2022]
Abstract
Apoptosis serves as a powerful defense against damaged or pathogen-infected cells. Since apoptosis is an effective defense against viral infection, many viruses including poxviruses, encode proteins to prevent or delay apoptosis. Here we show that ectromelia virus, the causative agent of mousepox encodes an anti-apoptotic protein EVM025. Here we demonstrate that expression of functional EVM025 is crucial to prevent apoptosis triggered by virus infection and staurosporine. We demonstrate that the expression of EVM025 prevents the conformational activation of the pro-apoptotic proteins Bak and Bax, allowing the maintenance of mitochondrial membrane integrity upon infection with ECTV. Additionally, EVM025 interacted with intracellular Bak. We were able to demonstrate that EVM025 ability to inhibit Bax activation is a function of its ability to inhibit the activity of an upstream BH3 only protein Bim. Collectively, our data indicates that EVM025 inhibits apoptosis by sequestering Bak and inhibiting the activity of Bak and Bax.
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Affiliation(s)
- Ninad Mehta
- Li Ka Shing Institute of Virology, Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, Alberta, Canada
| | - John Taylor
- Li Ka Shing Institute of Virology, Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, Alberta, Canada
| | - Douglas Quilty
- Li Ka Shing Institute of Virology, Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, Alberta, Canada
| | - Michele Barry
- Li Ka Shing Institute of Virology, Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, Alberta, Canada.
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304
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Sheng JJ, Chen Y, Chang H, Wang YY, Jiao B, Yu ZB. Multisite phosphorylation of Bcl-2 via protein kinase Cδfacilitates apoptosis of hypertrophic cardiomyocytes. Clin Exp Pharmacol Physiol 2014; 41:891-901. [DOI: 10.1111/1440-1681.12295] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2014] [Revised: 07/25/2014] [Accepted: 07/28/2014] [Indexed: 11/28/2022]
Affiliation(s)
- Juan-Juan Sheng
- Department of Aerospace Physiology; Fourth Military Medical University; Xi'an China
| | - Yan Chen
- Department of Aerospace Physiology; Fourth Military Medical University; Xi'an China
| | - Hui Chang
- Department of Aerospace Physiology; Fourth Military Medical University; Xi'an China
| | - Yun-Ying Wang
- Department of Aerospace Physiology; Fourth Military Medical University; Xi'an China
| | - Bo Jiao
- Department of Aerospace Physiology; Fourth Military Medical University; Xi'an China
| | - Zhi-Bin Yu
- Department of Aerospace Physiology; Fourth Military Medical University; Xi'an China
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305
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LIU FAYUAN, LIU GUOZHONG, LIANG WENNA, YE HONGZHI, WENG XIAPING, LIN PINGDONG, LI HUITING, CHEN JIASHOU, LIU XIANXIANG, LI XIHAI. Duhuo Jisheng decoction treatment inhibits the sodium nitroprussiate-induced apoptosis of chondrocytes through the mitochondrial-dependent signaling pathway. Int J Mol Med 2014; 34:1573-80. [DOI: 10.3892/ijmm.2014.1962] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2014] [Accepted: 09/29/2014] [Indexed: 11/05/2022] Open
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306
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Zerin T, Song HY, Kim YS. Extracellular signal-regulated kinase pathway play distinct role in acetochlor-mediated toxicity and intrinsic apoptosis in A549 cells. Toxicol In Vitro 2014; 29:85-92. [PMID: 25291404 DOI: 10.1016/j.tiv.2014.09.011] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2014] [Revised: 08/12/2014] [Accepted: 09/22/2014] [Indexed: 11/26/2022]
Abstract
Acetochlor (ACETO), a member of the chloroacetanilide family of herbicides, is widely used globally and is very frequently detected in watersheds of agricultural lands and fresh water streams. The human health consequences of environmental exposure to ACETO are unknown. This study was designed to elucidate the effect and molecular mechanisms of ACETO on human alveolar A549 cells. Established assays of cell viability and cytotoxicity were performed to detect the potential effects of ACETO on A549 cells. ACETO generated reactive oxygen species, which may have been crucial to apoptosis-mediated cytotoxicity. ACETO-treatment showed a concentration dependent up-regulation of pro-apoptotic proteins including Bax, Bak, BID and Bad, but a differential level of expression of anti-apoptotic proteins were observed, leading to the release of cytochrome c from mitochondria to the cytoplasm as well as activation of caspase-3, and cleavage of caspase-9 and PARP. ACETO also induced activation of extracellular signal-regulated kinase (ERK). Inhibition of the expression of ERK by PD98059 partially reversed ACETO-induced cytotoxicity, apoptosis and the expression of caspase-3, -9 and PARP in A549 cells. Comparative evaluation of the results indicates that the principal mechanism underlying ACETO-mediated cytotoxicity is likely to be through ERK-mediated intrinsic pathway of apoptosis.
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Affiliation(s)
- Tamanna Zerin
- Department of Microbiology, School of Medicine, Soonchunhyang University, Cheonan, Chungnam 330-090, South Korea
| | - Ho-Yeon Song
- Department of Microbiology, School of Medicine, Soonchunhyang University, Cheonan, Chungnam 330-090, South Korea
| | - Yong-Sik Kim
- Department of Microbiology, School of Medicine, Soonchunhyang University, Cheonan, Chungnam 330-090, South Korea.
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307
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The role of ubiquitin and ubiquitin-like modification systems in papillomavirus biology. Viruses 2014; 6:3584-611. [PMID: 25254385 PMCID: PMC4189040 DOI: 10.3390/v6093584] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2014] [Revised: 09/17/2014] [Accepted: 09/18/2014] [Indexed: 12/12/2022] Open
Abstract
Human papillomaviruses (HPVs) are small DNA viruses that are important etiological agents of a spectrum of human skin lesions from benign to malignant. Because of their limited genome coding capacity they express only a small number of proteins, only one of which has enzymatic activity. Additionally, the HPV productive life cycle is intimately tied to the epithelial differentiation program and they must replicate in what are normally non-replicative cells, thus, these viruses must reprogram the cellular environment to achieve viral reproduction. Because of these limitations and needs, the viral proteins have evolved to co-opt cellular processes primarily through protein-protein interactions with critical host proteins. The ubiquitin post-translational modification system and the related ubiquitin-like modifiers constitute a widespread cellular regulatory network that controls the levels and functions of thousands of proteins, making these systems an attractive target for viral manipulation. This review describes the interactions between HPVs and the ubiquitin family of modifiers, both to regulate the viral proteins themselves and to remodel the host cell to facilitate viral survival and reproduction.
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308
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Geserick P, Wang J, Feoktistova M, Leverkus M. The ratio of Mcl-1 and Noxa determines ABT737 resistance in squamous cell carcinoma of the skin. Cell Death Dis 2014; 5:e1412. [PMID: 25210795 PMCID: PMC4540197 DOI: 10.1038/cddis.2014.379] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2014] [Revised: 07/22/2014] [Accepted: 07/24/2014] [Indexed: 12/18/2022]
Abstract
Tumour progression and therapy resistance in squamous cell carcinoma of the skin (SCC) is strongly associated with resistance to intrinsic mitochondrial apoptosis. We thus investigated the role of various anti-apoptotic Bcl-2 proteins for apoptosis protection in SCC using the BH3 agonist ABT737 that can overcome multidomain Bcl-2 protein protection. Sensitive SCC cells underwent rapid loss of mitochondrial membrane potential (MMP), subsequent apoptosis concomitant with caspase-3 activation and an early release of mitochondria-derived cytochrome c and smac/DIABLO. In contrast, ABT737 resistance in subsets of SCC cells was not explained by XIAP, important for protection from DR-induced apoptosis in SCC. Of note, ABT737 did not prime SCC cells to DR-induced apoptosis. Interestingly, the ratio of Mcl-1 and Noxa determined sensitivity to ABT737: loss of Mcl-1 rendered resistant cells sensitive to ABT737, whereas loss of Noxa promoted resistance in sensitive cells. In line, suppression of Mcl-1 by the pan-Bcl-2 inhibitor Obatoclax or overexpression of Noxa rendered resistant SCC cells sensitive to BH3 mimetics. Our data indicate that targeting of the Mcl-1/Noxa axis is important to overcome resistance to mitochondrial apoptosis in SCC. Therefore, combination treatment of ABT737 or derivatives with Mcl-1 inhibitors, or inducers of Noxa, may represent a novel option of targeted therapy in metastatic SCC of the skin.
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Affiliation(s)
- P Geserick
- Section of Molecular Dermatology, Department of Dermatology, Venerology, and Allergology, Medical Faculty Mannheim, University Heidelberg, Mannheim, Germany
| | - J Wang
- Section of Molecular Dermatology, Department of Dermatology, Venerology, and Allergology, Medical Faculty Mannheim, University Heidelberg, Mannheim, Germany
| | - M Feoktistova
- Section of Molecular Dermatology, Department of Dermatology, Venerology, and Allergology, Medical Faculty Mannheim, University Heidelberg, Mannheim, Germany
| | - M Leverkus
- Section of Molecular Dermatology, Department of Dermatology, Venerology, and Allergology, Medical Faculty Mannheim, University Heidelberg, Mannheim, Germany
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309
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Cartron PF, Petit E, Bellot G, Oliver L, Vallette FM. Metaxins 1 and 2, two proteins of the mitochondrial protein sorting and assembly machinery, are essential for Bak activation during TNF alpha triggered apoptosis. Cell Signal 2014; 26:1928-34. [DOI: 10.1016/j.cellsig.2014.04.021] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2014] [Accepted: 04/27/2014] [Indexed: 10/25/2022]
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310
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Maniam S, Coutts AS, Stratford MR, McGouran J, Kessler B, La Thangue NB. Cofactor Strap regulates oxidative phosphorylation and mitochondrial p53 activity through ATP synthase. Cell Death Differ 2014; 22:156-63. [PMID: 25168243 DOI: 10.1038/cdd.2014.135] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2014] [Revised: 06/16/2014] [Accepted: 07/22/2014] [Indexed: 12/18/2022] Open
Abstract
Metabolic reprogramming is a hallmark of cancer cells. Strap (stress-responsive activator of p300) is a novel TPR motif OB-fold protein that contributes to p53 transcriptional activation. We show here that, in addition to its established transcriptional role, Strap is localised at mitochondria where one of its key interaction partners is ATP synthase. Significantly, the interaction between Strap and ATP synthase downregulates mitochondrial ATP production. Under glucose-limiting conditions, cancer cells are sensitised by mitochondrial Strap to apoptosis, which is rescued by supplementing cells with an extracellular source of ATP. Furthermore, Strap augments the apoptotic effects of mitochondrial p53. These findings define Strap as a dual regulator of cellular reprogramming: first as a nuclear transcription cofactor and second in the direct regulation of mitochondrial respiration.
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Affiliation(s)
- S Maniam
- Laboratory of Cancer Biology, Department of Oncology, Medical Science Division, University of Oxford, Oxford, UK
| | - A S Coutts
- Laboratory of Cancer Biology, Department of Oncology, Medical Science Division, University of Oxford, Oxford, UK
| | - M R Stratford
- Department of Oncology, Medical Science Division, University of Oxford, Oxford, UK
| | - J McGouran
- Target Discovery Institute, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - B Kessler
- Target Discovery Institute, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - N B La Thangue
- Laboratory of Cancer Biology, Department of Oncology, Medical Science Division, University of Oxford, Oxford, UK
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311
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Bax targets mitochondria by distinct mechanisms before or during apoptotic cell death: a requirement for VDAC2 or Bak for efficient Bax apoptotic function. Cell Death Differ 2014; 21:1925-35. [PMID: 25146925 DOI: 10.1038/cdd.2014.119] [Citation(s) in RCA: 92] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2014] [Revised: 06/24/2014] [Accepted: 07/13/2014] [Indexed: 01/15/2023] Open
Abstract
In non-apoptotic cells, Bak constitutively resides in the mitochondrial outer membrane. In contrast, Bax is in a dynamic equilibrium between the cytosol and mitochondria, and is commonly predominant in the cytosol. In response to an apoptotic stimulus, Bax and Bak change conformation, leading to Bax accumulation at mitochondria and Bak/Bax oligomerization to form a pore in the mitochondrial outer membrane that is responsible for cell death. Using blue native-PAGE to investigate how Bax oligomerizes in the mitochondrial outer membrane, we observed that, like Bak, a proportion of Bax that constitutively resides at mitochondria associates with voltage-dependent anion channel (VDAC)2 prior to an apoptotic stimulus. During apoptosis, Bax dissociates from VDAC2 and homo-oligomerizes to form high molecular weight oligomers. In cells that lack VDAC2, constitutive mitochondrial localization of Bax and Bak was impaired, suggesting that VDAC2 has a role in Bax and Bak import to, or stability at, the mitochondrial outer membrane. However, following an apoptotic stimulus, Bak and Bax retained the ability to accumulate at VDAC2-deficient mitochondria and to mediate cell death. Silencing of Bak in VDAC2-deficient cells indicated that Bax required either VDAC2 or Bak in order to translocate to and oligomerize at the mitochondrial outer membrane to efficiently mediate apoptosis. In contrast, efficient Bak homo-oligomerization at the mitochondrial outer membrane and its pro-apoptotic function required neither VDAC2 nor Bax. Even a C-terminal mutant of Bax (S184L) that localizes to mitochondria did not constitutively target mitochondria deficient in VDAC2, but was recruited to mitochondria following an apoptotic stimulus dependent on Bak or upon over-expression of Bcl-xL. Together, our data suggest that Bax localizes to the mitochondrial outer membrane via alternate mechanisms, either constitutively via an interaction with VDAC2 or after activation via interaction with Bcl-2 family proteins.
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312
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Andreu-Fernández V, Genoves A, Lee TH, Stellato M, Lucantoni F, Orzáez M, Mingarro I, Aguilar MI, Pérez-Payá E. Peptides derived from the transmembrane domain of Bcl-2 proteins as potential mitochondrial priming tools. ACS Chem Biol 2014; 9:1799-811. [PMID: 24905660 DOI: 10.1021/cb5002679] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The Bcl-2 family of proteins is crucial for apoptosis regulation. Members of this family insert through a specific C-terminal anchoring transmembrane domain (TMD) in the mitochondrial outer membrane where they hierarchically interact to determine cell fate. While the mitochondrial membrane has been proposed to actively participate in these protein-protein interactions, the influence of the TMD in the membrane-mediated interaction is poorly understood. Synthetic peptides (TMD-pepts) corresponding to the putative TMD of antiapoptotic (Bcl-2, Bcl-xL, Bcl-w, and Mcl-1) and pro-apoptotic (Bax, Bak) members were synthesized and characterized. TMD-pepts bound more efficiently to mitochondria-like bilayers than to plasma membrane-like bilayers, and higher binding correlated with greater membrane perturbation. The Bcl-2 TMD peptides promoted mitochondrial outer membrane permeabilization (MOMP) and cytochrome c release from isolated mitochondria and different cell lines. TMD-pepts exhibited nonapoptotic pro-death activity when apoptosis stimuli were absent. In addition, the peptides enhanced the apoptotic pathway induced by chemotherapeutic agents in cotreatment. Overall, the membrane perturbation effects of the TMD-pepts observed in the present study open the way for their use as new chemical tools to sensitize tumor cells to chemotherapeutic agents, in accordance with the concept of mitochondria priming.
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Affiliation(s)
- Vicente Andreu-Fernández
- Laboratory
of Peptide and Protein Chemistry, Centro de Investigación Príncipe Felipe, E-46012 Valencia, Spain
| | - Ainhoa Genoves
- Laboratory
of Peptide and Protein Chemistry, Centro de Investigación Príncipe Felipe, E-46012 Valencia, Spain
- Instituto de Biomedicina de Valencia, IBV-CSIC, E-46010 Valencia, Spain
| | - Tzong-Hsien Lee
- Department
of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria 3800 Australia
| | - Matthew Stellato
- Department
of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria 3800 Australia
| | - Federico Lucantoni
- Laboratory
of Peptide and Protein Chemistry, Centro de Investigación Príncipe Felipe, E-46012 Valencia, Spain
| | - Mar Orzáez
- Laboratory
of Peptide and Protein Chemistry, Centro de Investigación Príncipe Felipe, E-46012 Valencia, Spain
| | - Ismael Mingarro
- Departament
de Bioquímica i Biologia Molecular, Universitat de València, 46100 Burjassot, Spain
| | - Marie-Isabel Aguilar
- Department
of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria 3800 Australia
| | - Enrique Pérez-Payá
- Laboratory
of Peptide and Protein Chemistry, Centro de Investigación Príncipe Felipe, E-46012 Valencia, Spain
- Instituto de Biomedicina de Valencia, IBV-CSIC, E-46010 Valencia, Spain
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313
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Lemke J, von Karstedt S, Zinngrebe J, Walczak H. Getting TRAIL back on track for cancer therapy. Cell Death Differ 2014; 21:1350-64. [PMID: 24948009 PMCID: PMC4131183 DOI: 10.1038/cdd.2014.81] [Citation(s) in RCA: 369] [Impact Index Per Article: 36.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2014] [Revised: 04/14/2014] [Accepted: 04/15/2014] [Indexed: 02/07/2023] Open
Abstract
Unlike other members of the TNF superfamily, the TNF-related apoptosis-inducing ligand (TRAIL, also known as Apo2L) possesses the unique capacity to induce apoptosis selectively in cancer cells in vitro and in vivo. This exciting discovery provided the basis for the development of TRAIL-receptor agonists (TRAs), which have demonstrated robust anticancer activity in a number of preclinical studies. Subsequently initiated clinical trials testing TRAs demonstrated, on the one hand, broad tolerability but revealed, on the other, that therapeutic benefit was rather limited. Several factors that are likely to account for TRAs' sobering clinical performance have since been identified. First, because of initial concerns over potential hepatotoxicity, TRAs with relatively weak agonistic activity were selected to enter clinical trials. Second, although TRAIL can induce apoptosis in several cancer cell lines, it has now emerged that many others, and importantly, most primary cancer cells are resistant to TRAIL monotherapy. Third, so far patients enrolled in TRA-employing clinical trials were not selected for likelihood of benefitting from a TRA-comprising therapy on the basis of a valid(ated) biomarker. This review summarizes and discusses the results achieved so far in TRA-employing clinical trials in the light of these three shortcomings. By integrating recent insight on apoptotic and non-apoptotic TRAIL signaling in cancer cells, we propose approaches to introduce novel, revised TRAIL-based therapeutic concepts into the cancer clinic. These include (i) the use of recently developed highly active TRAs, (ii) the addition of efficient, but cancer-cell-selective TRAIL-sensitizing agents to overcome TRAIL resistance and (iii) employing proteomic profiling to uncover resistance mechanisms. We envisage that this shall enable the design of effective TRA-comprising therapeutic concepts for individual cancer patients in the future.
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Affiliation(s)
- J Lemke
- 1] Centre for Cell Death, Cancer and Inflammation (CCCI), UCL Cancer Institute, University College London, 72 Huntley Street, London WC1E 6DD, UK [2] Clinic of General and Visceral Surgery, University of Ulm, Albert-Einstein-Allee 23, 89081 Ulm, Germany
| | - S von Karstedt
- Centre for Cell Death, Cancer and Inflammation (CCCI), UCL Cancer Institute, University College London, 72 Huntley Street, London WC1E 6DD, UK
| | - J Zinngrebe
- Centre for Cell Death, Cancer and Inflammation (CCCI), UCL Cancer Institute, University College London, 72 Huntley Street, London WC1E 6DD, UK
| | - H Walczak
- Centre for Cell Death, Cancer and Inflammation (CCCI), UCL Cancer Institute, University College London, 72 Huntley Street, London WC1E 6DD, UK
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314
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Functions of the C-terminal domains of apoptosis-related proteins of the Bcl-2 family. Chem Phys Lipids 2014; 183:77-90. [PMID: 24892727 DOI: 10.1016/j.chemphyslip.2014.05.003] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2014] [Revised: 05/12/2014] [Accepted: 05/13/2014] [Indexed: 02/06/2023]
Abstract
Bcl-2 family proteins are involved in cell homeostasis, where they regulate cell death. Some of these proteins are pro-apoptotic and others pro-survival. Moreover, many of them share a similar domain composition with several of the so-called BH domains, although some only have a BH3 domain. A C-terminal domain is present in all the multi-BH domain proteins and in some of the BH3-only ones. This C-terminal domain is hydrophobic or amphipathic, for which reason it was thought when they were discovered that they were membrane anchors. Although this is indeed one of their functions, it has since been observed that they may also serve as regulators of the function of some members of this family, such as Bax. They may also serve to recognize the target membrane of some of these proteins, which only after an apoptotic signal, are incorporated into a membrane. It has been shown that peptides that imitate the sequence of C-terminal domains can form pores and may serve as a model to design cytotoxic molecules.
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315
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Liu CJ, Lin JY. Protective effects of strawberry and mulberry fruit polysaccharides on inflammation and apoptosis in murine primary splenocytes. J Food Drug Anal 2014. [PMCID: PMC9359330 DOI: 10.1016/j.jfda.2014.01.015] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
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316
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Gonadotropin-releasing hormone agonists sensitize, and resensitize, prostate cancer cells to docetaxel in a p53-dependent manner. PLoS One 2014; 9:e93713. [PMID: 24722580 PMCID: PMC3983111 DOI: 10.1371/journal.pone.0093713] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2013] [Accepted: 03/05/2014] [Indexed: 11/29/2022] Open
Abstract
Gonadotropin-releasing hormone (GnRH) receptors are expressed in prostate cancer, specifically in the most aggressive stage of the tumor (castration-resistant prostate cancer, CRPC) for which the standard treatment, docetaxel-based chemotherapy, can only improve the median survival time by few months. We previously showed that GnRH agonists exert an antitumor activity in CRPC cells; however, a link between GnRH receptors and the apoptotic machinery remains to be defined. Aim of this study was to evaluate whether, in CRPC cells, GnRH agonists might affect the expression/activity of apoptosis-related proteins and might sensitize, or resensitize, cancer cells to chemotherapeutics. We demonstrated that, in p53-positive DU145 cells, GnRH agonists: a) increase the expression of the proapoptotic protein Bax; this effect is mediated by the phosphorylation (activation) of p53, triggered by the p38 MAPK; b) potentiate the antiproliferative/proapoptotic activity of docetaxel; c) resensitize docetaxel-resistant cells to the antitumor activity of the cytotoxic drug. These data indicate that GnRH agonists sensitize and, more importantly, resensitize DU145 CRPC cells to chemotherapy in a p53-dependent manner. To confirm the crucial role of p53 in the activity of GnRH agonists, experiments were performed in p53-null PC3 cells. We found that GnRH agonists fail to increase Bax expression and do not potentiate the cytotoxic activity of docetaxel. These results may provide a rationale for novel combination treatment strategies, especially for docetaxel-resistant CRPC patients expressing a functional p53 protein.
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317
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Regulators of mitochondrial Ca2+ homeostasis in cerebral ischemia. Cell Tissue Res 2014; 357:395-405. [DOI: 10.1007/s00441-014-1807-y] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2013] [Accepted: 01/10/2014] [Indexed: 02/06/2023]
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318
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Raemy E, Martinou JC. Involvement of cardiolipin in tBID-induced activation of BAX during apoptosis. Chem Phys Lipids 2014; 179:70-4. [DOI: 10.1016/j.chemphyslip.2013.12.002] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2013] [Revised: 12/02/2013] [Accepted: 12/04/2013] [Indexed: 02/08/2023]
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319
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Roy MJ, Vom A, Czabotar PE, Lessene G. Cell death and the mitochondria: therapeutic targeting of the BCL-2 family-driven pathway. Br J Pharmacol 2014; 171:1973-87. [PMID: 24117105 PMCID: PMC3976616 DOI: 10.1111/bph.12431] [Citation(s) in RCA: 87] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2013] [Revised: 09/13/2013] [Accepted: 09/18/2013] [Indexed: 12/27/2022] Open
Abstract
The principal biological role of mitochondria is to supply energy to cells; although intriguingly, evolution has bestowed another essential function upon these cellular organelles: under physiological stress, mitochondria become the cornerstone of apoptotic cell death. Specifically, mitochondrial outer membrane permeabilization (MOMP) allows cell death factors such as cytochrome c to be released into the cytoplasm, thus inducing caspase activation and the eventual destruction of essential cellular components. Proteins of the B-cell lymphoma 2 (BCL-2) family control the tightly regulated pathway that causes MOMP. The equilibrium between pro-survival and pro-apoptotic members of the BCL-2 family dictates the fate of cells, the homeostasis of organs and, by extension, the health of whole organisms. Dysregulation of this equilibrium is involved in a large number of diseases such as cancer, autoimmunity and neurodegenerative conditions. Modulating the activity of the BCL-2 family of proteins with small molecules or peptides is an attractive but challenging therapeutic goal. This review highlights the latest developments in this field and provides evidence that this strategy is likely to have a positive effect on the treatment of still poorly addressed medical conditions.
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Affiliation(s)
- M J Roy
- Divisions of Chemical and Structural Biology, The Walter and Eliza Hall Institute of Medical ResearchMelbourne, Vic, Australia
- Department of Medical Biology, The University of MelbourneMelbourne, Vic, Australia
| | - A Vom
- Divisions of Chemical and Structural Biology, The Walter and Eliza Hall Institute of Medical ResearchMelbourne, Vic, Australia
- Department of Medical Biology, The University of MelbourneMelbourne, Vic, Australia
| | - P E Czabotar
- Divisions of Chemical and Structural Biology, The Walter and Eliza Hall Institute of Medical ResearchMelbourne, Vic, Australia
- Department of Medical Biology, The University of MelbourneMelbourne, Vic, Australia
| | - G Lessene
- Divisions of Chemical and Structural Biology, The Walter and Eliza Hall Institute of Medical ResearchMelbourne, Vic, Australia
- Department of Medical Biology, The University of MelbourneMelbourne, Vic, Australia
- Department of Pharmacology and Therapeutics, The University of MelbourneMelbourne, Vic, Australia
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320
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Lan WB, Lin JH, Chen XW, Wu CY, Zhong GX, Zhang LQ, Lin WP, Liu WN, Li X, Lin JL. Overexpressing neuroglobin improves functional recovery by inhibiting neuronal apoptosis after spinal cord injury. Brain Res 2014; 1562:100-8. [PMID: 24675030 DOI: 10.1016/j.brainres.2014.03.020] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2013] [Revised: 02/08/2014] [Accepted: 03/17/2014] [Indexed: 01/10/2023]
Abstract
The current study was performed to evaluate the mechanisms and therapeutic effects of overexpressing neuroglobin (Ngb) on spinal cord injury (SCI). Adeno-associated virus (AAV) was injected in the T12 section 7 days before SCI. Animals were randomly divided into four groups: a sham group, a vehicle group, an AAV-EGFP group and an AAV-Ngb group. Recovery of hind limb locomotor function was determined during the 3-week post operation period by the Basso, Beattie and Bresnahan locomotor rating scale. At 24 h after SCI and at the end of the study, the segments of spinal cord, centered with the lesion site were harvested for histopathological analysis. Immunofluorescence was performed using antibodies to recognize neuN in the lesion sections. At 24 h after SCI, the spinal cord tissue samples were removed to analyze tissue concentrations of superoxide dismutase (SOD) and malondialdehyde (MDA). Apoptotic cells were assessed using a terminal deoxynucleotidyl transferase, dUTP nick end labeling (TUNEL) kit. The expression of bcl-2, bax, cytochrome c, and cleaved caspase-3, were determined by Western blot assay and immunostaining analysis. The results showed that animals overexpressing Ngb had significantly greater recovery of locomotor function, less neuronal loss and fewer apoptotic cells. In addition, overexpressing Ngb significantly increased bcl-2 expression and SOD level, decreased bax expression, attenuated the release of cytochrome c from mitochondria to the cytosol fraction, and reduced the activity of caspase-3 and MDA level after SCI. These findings suggest, that overexpressing Ngb can significantly improve the recovery of locomotor function. This neuroprotective effect may be associated with the inhibition of neural apoptosis via the mitochondrial pathway.
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Affiliation(s)
- Wen-Bin Lan
- The First Clinical Medical College of Fujian Medical University, Fuzhou, Fujian, China
| | - Jian-Hua Lin
- The First Clinical Medical College of Fujian Medical University, Fuzhou, Fujian, China.
| | - Xuan-Wei Chen
- The First Clinical Medical College of Fujian Medical University, Fuzhou, Fujian, China
| | - Chao-Yang Wu
- The First Clinical Medical College of Fujian Medical University, Fuzhou, Fujian, China
| | - Guang-Xian Zhong
- The First Clinical Medical College of Fujian Medical University, Fuzhou, Fujian, China
| | - Li-Qun Zhang
- The First Clinical Medical College of Fujian Medical University, Fuzhou, Fujian, China
| | - Wen-Ping Lin
- Department of Orthopedics, the 2nd Affiliated Hospital of Fujian Medical University, Quanzhou, Fujian, China
| | - Wei-Nan Liu
- Department of Orthopedics, the Affiliated People׳s Hospital of Fujian University of Traditional Chinese Medicine, Fuzhou, Fujian, China
| | - Xiang Li
- The First Clinical Medical College of Fujian Medical University, Fuzhou, Fujian, China
| | - Jin-Luan Lin
- The First Clinical Medical College of Fujian Medical University, Fuzhou, Fujian, China
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321
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Protein profiling of Helicobacter pylori-associated gastric cancer. THE AMERICAN JOURNAL OF PATHOLOGY 2014; 184:1343-54. [PMID: 24589339 DOI: 10.1016/j.ajpath.2014.01.027] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2013] [Revised: 12/18/2013] [Accepted: 01/06/2014] [Indexed: 02/02/2023]
Abstract
Helicobacter pylori infection is an initiating factor in the development of gastric cancer. Gastric cancer can be divided into two groups on the basis of H. pylori serological status; seropositive H. pylori status predicts favorable prognosis in patients with gastric cancer. By using the protein pathway array, we identified 20 differentially expressed proteins in primary gastric cancer tissues between the H. pylori-seropositive and H. pylori-seronegative groups. Our results indicate that both brassinosteroid insensitive 1-associated kinase 1 and calpastatin are favorable prognostic factors in H. pylori-seropositive gastric cancer patients. In contrast, dachshund homolog 1 is a favorable prognostic factor in H. pylori-seronegative gastric cancer patients. Different signaling pathways were found to be altered between H. pylori-seropositive and H. pylori-seronegative gastric cancer, which may account for the different tumorigenesis and outcomes between these two subsets of patients.
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322
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Song SS, Lee WK, Aluvila S, Oh KJ, Yu YG. Identification of Inhibitors Against BAK Pore Formation using an Improved in vitro Assay System. B KOREAN CHEM SOC 2014. [DOI: 10.5012/bkcs.2014.35.2.419] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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323
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Control of apoptosis by the BCL-2 protein family: implications for physiology and therapy. Nat Rev Mol Cell Biol 2014; 15:49-63. [PMID: 24355989 DOI: 10.1038/nrm3722] [Citation(s) in RCA: 2201] [Impact Index Per Article: 220.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The BCL-2 protein family determines the commitment of cells to apoptosis, an ancient cell suicide programme that is essential for development, tissue homeostasis and immunity. Too little apoptosis can promote cancer and autoimmune diseases; too much apoptosis can augment ischaemic conditions and drive neurodegeneration. We discuss the biochemical, structural and genetic studies that have clarified how the interplay between members of the BCL-2 family on mitochondria sets the apoptotic threshold. These mechanistic insights into the functions of the BCL-2 family are illuminating the physiological control of apoptosis, the pathological consequences of its dysregulation and the promising search for novel cancer therapies that target the BCL-2 family.
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324
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Yao S, Westphal D, Babon JJ, Thompson GV, Robin AY, Adams JM, Colman PM, Czabotar PE. NMR studies of interactions between Bax and BH3 domain-containing peptides in the absence and presence of CHAPS. Arch Biochem Biophys 2014; 545:33-43. [PMID: 24434006 DOI: 10.1016/j.abb.2014.01.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2013] [Revised: 12/26/2013] [Accepted: 01/06/2014] [Indexed: 01/27/2023]
Abstract
Activation and oligomerisation of Bax, a key pro-apoptotic Bcl-2 family protein, are key steps in the mitochondrial pathway to apoptosis. The signals for apoptosis are conveyed by the distantly related BH3-only proteins, which use their short BH3 domain, an amphipathic α-helix, to interact with other Bcl-2 family members. Here we report an NMR study of interactions between BaxΔC and BH3 domain-containing peptides in the absence and presence of CHAPS, a zwitterionic detergent. We find for the first time that CHAPS interacts weakly with BaxΔC (fast exchange on the NMR chemical shift timescale), at concentrations below micelle formation and with an estimated Kd in the tens of mM. Direct and relatively strong-interactions (slow exchange on the NMR chemical shift timescale) were also observed for BaxΔC with BaxBH3 (estimated Kd of circa 150μM) or BimBH3 in the absence of CHAPS. The interaction with either peptide alone induced widespread chemical shift perturbations to BaxΔC in solution which implies that BaxΔC might have undergone significant conformation change upon binding the BH3 peptide. However, BaxΔC remained monomeric upon binding either CHAPS or a BH3 peptide alone, but the presence of both provoked it to form a dimer.
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Affiliation(s)
- Shenggen Yao
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia; Department of Medical Biology, The University of Melbourne, Victoria 3010, Australia; Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Victoria 3010, Australia.
| | - Dana Westphal
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia; Department of Medical Biology, The University of Melbourne, Victoria 3010, Australia
| | - Jeffrey J Babon
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia; Department of Medical Biology, The University of Melbourne, Victoria 3010, Australia
| | - Geoff V Thompson
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia
| | - Adeline Y Robin
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia; Department of Medical Biology, The University of Melbourne, Victoria 3010, Australia
| | - Jerry M Adams
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia; Department of Medical Biology, The University of Melbourne, Victoria 3010, Australia
| | - Peter M Colman
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia; Department of Medical Biology, The University of Melbourne, Victoria 3010, Australia
| | - Peter E Czabotar
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia; Department of Medical Biology, The University of Melbourne, Victoria 3010, Australia.
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325
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Bleicken S, García-Sáez AJ. New biophysical methods to study the membrane activity of Bcl-2 proteins. Methods Mol Biol 2014; 1176:191-207. [PMID: 25030929 DOI: 10.1007/978-1-4939-0992-6_16] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The proteins of Bcl-2 family are key regulators of apoptosis. Many Bcl-2 proteins have the unique ability to switch between two possible conformations, soluble in the cytosol or associated to cellular membranes. Importantly, their membrane-inserted form is the main responsible for their apoptotic function. Unfortunately, there are only a limited number of methods available to study the membrane activity of these proteins. Here, we present a methodology to study protein binding to membranes and membrane permeabilization at the single vesicle level. It is based on purified proteins and giant unilamellar vesicles and involves directly visualization of the process with a confocal microscope. This approach allows for the characterization of the membrane activity of the Bcl-2 proteins (or of any other pore-forming molecule) with unprecedented detail.
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Affiliation(s)
- Stephanie Bleicken
- Membrane Biophysics, Max Planck Institute for Intelligent Systems, Heisenbergstr. 3, 70569, Stuttgart, Germany
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326
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Alkotaji M, Pluen A, Zindy E, Hamrang Z, Aojula H. On the Cellular Uptake and Membrane Effect of the Multifunctional Peptide, TatLK15. J Pharm Sci 2014; 103:293-304. [DOI: 10.1002/jps.23778] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2013] [Revised: 09/26/2013] [Accepted: 10/18/2013] [Indexed: 11/08/2022]
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327
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Abstract
The cell membrane is crucial for protection of the cell from its environment. MACPF/CDC proteins are a large superfamily known to be essential for bacterial pathogenesis and proper functioning of the immune system. The three most studied groups of MACPF/CDC proteins are cholesterol-dependent cytolysins from bacteria, the membrane attack complex of complement and human perforin. Their primary function is to form transmembrane pores in target cell membranes. The common mechanism of action comprises water-soluble monomeric proteins binding to the host cell membrane, oligomerization, and formation of a functional pore. This causes a disturbance in gradients of ions and other molecules across the membrane and can lead to cell death. Cells react to this form of attack in a complex manner. Responses can be general, like removing the perforated part of the membrane, or more specific, in many cases depending on binding of proteins to specific receptors to trigger various signalling cascades.
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328
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Tokar T, Ulicny J. The mathematical model of the Bcl-2 family mediated MOMP regulation can perform a non-trivial pattern recognition. PLoS One 2013; 8:e81861. [PMID: 24386084 PMCID: PMC3873269 DOI: 10.1371/journal.pone.0081861] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2013] [Accepted: 10/21/2013] [Indexed: 12/22/2022] Open
Abstract
Interactions between individual members of the B-cell lymphoma 2 (Bcl-2) family of proteins form a regulatory network governing mitochondrial outer membrane permeabilization (MOMP). Bcl-2 family initiated MOMP causes release of the inter-membrane pro-apoptotic proteins to cytosol and creates a cytosolic environment suitable for the executionary phase of apoptosis. We designed the mathematical model of this regulatory network where the synthesis rates of the Bcl-2 family members served as the independent inputs. Using computational simulations, we have then analyzed the response of the model to up-/downregulation of the Bcl-2 proteins. Under several assumptions, and using estimated reaction parameters, a non-linear stimulus-response emerged, whose characteristics are associated with bistability and switch-like behavior. Interestingly, using the principal component analysis (PCA) we have shown that the given model of the Bcl-2 family interactions classifies the random combinations of inputs into two distinct classes, and responds to these by one of the two qualitatively distinct outputs. As we showed, the emergence of this behavior requires specific organization of the interactions between particular Bcl-2 proteins.
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Affiliation(s)
- Tomas Tokar
- Department of Biophysics, University of P. J. Safarik in Kosice, Kosice, Slovakia
| | - Jozef Ulicny
- Department of Biophysics, University of P. J. Safarik in Kosice, Kosice, Slovakia
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329
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Makovitzki-Avraham E, Daniel-Carmi V, Alteber Z, Farago M, Tzehoval E, Eisenbach L. The human ISG12a gene is a novel caspase dependent and p53 independent pro-apoptotic gene, that is overexpressed in breast cancer. CELL BIOLOGY INTERNATIONAL REPORTS 2013. [DOI: 10.1002/cbi3.10009] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
| | - Vered Daniel-Carmi
- Department of Immunology; The Weizmann Institute of Science; Rehovot 76100 Israel
| | - Zoya Alteber
- Department of Immunology; The Weizmann Institute of Science; Rehovot 76100 Israel
| | - Marganit Farago
- Department of Immunology; The Weizmann Institute of Science; Rehovot 76100 Israel
| | - Esther Tzehoval
- Department of Immunology; The Weizmann Institute of Science; Rehovot 76100 Israel
| | - Lea Eisenbach
- Department of Immunology; The Weizmann Institute of Science; Rehovot 76100 Israel
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330
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Building blocks of the apoptotic pore: how Bax and Bak are activated and oligomerize during apoptosis. Cell Death Differ 2013; 21:196-205. [PMID: 24162660 DOI: 10.1038/cdd.2013.139] [Citation(s) in RCA: 292] [Impact Index Per Article: 26.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2013] [Revised: 09/03/2013] [Accepted: 09/03/2013] [Indexed: 12/18/2022] Open
Abstract
The central role of the Bcl-2 family in regulating apoptotic cell death was first identified in the 1980s. Since then, significant in-roads have been made in identifying the multiple members of this family, characterizing their form and function and understanding how their interactions determine whether a cell lives or dies. In this review we focus on the recent progress made in characterizing the proapoptotic Bcl-2 family members, Bax and Bak. This progress has resolved longstanding controversies, but has also challenged established theories in the apoptosis field. We will discuss different models of how these two proteins become activated and different 'modes' by which they are inhibited by other Bcl-2 family members. We will also discuss novel conformation changes leading to Bak and Bax oligomerization and speculate how these oligomers might permeabilize the mitochondrial outer membrane.
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331
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ROS-dependent phosphorylation of Bax by wortmannin sensitizes melanoma cells for TRAIL-induced apoptosis. Cell Death Dis 2013; 4:e839. [PMID: 24113173 PMCID: PMC3824654 DOI: 10.1038/cddis.2013.344] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2013] [Revised: 07/26/2013] [Accepted: 08/09/2013] [Indexed: 02/08/2023]
Abstract
The pathways of reactive oxygen species (ROS)-mediated apoptosis induction, of Bax activation and the sensitization of tumor cells for TRAIL (TNF-related apoptosis-inducing ligand)-induced apoptosis are still largely elusive. Here, sensitization of melanoma cells for TRAIL by the PI3-kinase inhibitor wortmannin correlated to the activation of mitochondrial apoptosis pathways. Apoptosis was dependent on Bax and abrogated by Bcl-2 overexpression. The synergistic enhancement was explained by Bax activation through wortmannin, which tightly correlated to the characteristic Bax phosphorylation patterns. Thus, wortmannin resulted in early reduction of the Bax-inactivating phosphorylation at serine-184, whereas the Bax-activating phosphorylation at threonine-167 was enhanced. Proving the responsibility of the pathway, comparable effects were obtained with an Akt inhibitor (MK-2206); while suppressed phosphorylation of serine-184 may be attributed to reduced Akt activity itself, the causes of enhanced threonine-167 phosphorylation were addressed here. Characteristically, production of ROS was seen early in response to wortmannin and MK-2206. Providing the link between ROS and Bax, we show that abrogated ROS production by α-tocopherol or by NADPH oxidase 4 (NOX4) siRNA suppressed apoptosis and Bax activation. This correlated with reduced Bax phosphorylation at threonine-167. The data unraveled a mechanism by which NOX4-dependent ROS production controls apoptosis via Bax phosphorylation. The pathway may be considered for proapoptotic, anticancer strategies.
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332
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A recombinant trans-membrane protein hMnSOD–R9 inhibits the proliferation of cervical cancer cells in vitro. Mol Cell Biochem 2013; 385:79-86. [DOI: 10.1007/s11010-013-1816-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2013] [Accepted: 09/13/2013] [Indexed: 12/30/2022]
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333
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Terfenadine induces anti-proliferative and apoptotic activities in human hormone-refractory prostate cancer through histamine receptor-independent Mcl-1 cleavage and Bak up-regulation. Naunyn Schmiedebergs Arch Pharmacol 2013; 387:33-45. [PMID: 24048439 DOI: 10.1007/s00210-013-0912-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2013] [Accepted: 08/28/2013] [Indexed: 12/27/2022]
Abstract
Although the results of several studies have underscored the regulatory effect of H1-histamine receptors in cell proliferation of some cancer cell types, its effect in prostate cancers remains unclear. We have therefore studied the effect of terfenadine (an H1-histamine receptor antagonist) in prostate cancer cell lines. Our data demonstrate that terfenadine was effective against PC-3 and DU-145 cells (two prostate cancer cell lines). In contrast, based on the sulforhodamine B assay, loratadine had less potency while fexofenadine and diphenhydramine had little effect. Terfenadine induced the cleavage of Mcl-1 cleavage into a pro-apoptotic 28-kDa fragment and up-regulation of Bak, resulting in the loss of mitochondrial membrane potential (ΔΨm) and the release of cytochrome c and apoptosis-inducing factor into the cytosol. The activation of caspase cascades was detected to be linked to terfenadine action. Bak up-regulation was also examined at both the transcriptional and translational levels, and Bak activation was validated based on conformational change to expose the N terminus. Terfenadine also induced an indirect-but not direct-DNA damage response through the cleavage and activation of caspase-2, phosphorylation and activation of Chk1 and Chk2 kinases, phosphorylation of RPA32 and acetylation of Histone H3; these processes were highly correlated to severe mitochondrial dysfunction and the activation of caspase cascades. In conclusion, terfenadine induced apoptotic signaling cascades against HRPCs in a sequential manner. The exposure of cells to terfenadine caused the up-regulation and activation of Bak and the cleavage of Mcl-1, leading to the loss of ΔΨm and activation of caspase cascades which further resulted in DNA damage response and cell apoptosis.
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334
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Zhang Y, Iqbal S, O'Leary MFN, Menzies KJ, Saleem A, Ding S, Hood DA. Altered mitochondrial morphology and defective protein import reveal novel roles for Bax and/or Bak in skeletal muscle. Am J Physiol Cell Physiol 2013; 305:C502-11. [DOI: 10.1152/ajpcell.00058.2013] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The function Bax and/or Bak in constituting a gateway for mitochondrial apoptosis in response to apoptotic stimuli has been unequivocally demonstrated. However, recent work has suggested that Bax/Bak may have unrecognized nonapoptotic functions related to mitochondrial function in nonstressful environments. Wild-type (WT) and Bax/Bak double knockout (DKO) mice were used to determine alternative roles for Bax and Bak in mitochondrial morphology and protein import in skeletal muscle. The absence of Bax and/or Bak altered mitochondrial dynamics by regulating protein components of the organelle fission and fusion machinery. Moreover, DKO mice exhibited defective mitochondrial protein import, both into the matrix and outer membrane compartments, which was consistent with our observations of impaired membrane potential and attenuated expression of protein import machinery (PIM) components in intermyofibrillar mitochondria. Furthermore, the cytosolic chaperones heat-shock protein 90 (Hsp90) and binding immunoglobulin protein (BiP) were markedly increased with the deletion of Bax/Bak, indicating that the cytosolic environment related to protein folding may be changed in DKO mice. Interestingly, endurance training fully restored the deficiency of protein import in DKO mice, likely via the upregulation of PIM components and through improved cytosolic chaperone protein expression. Thus our results emphasize novel roles for Bax and/or Bak in mitochondrial function and provide evidence, for the first time, of a curative function of exercise training in ameliorating a condition of defective mitochondrial protein import.
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Affiliation(s)
- Yuan Zhang
- School of Kinesiology and Health Science, York University, Toronto, Ontario, Canada
- Muscle Health Research Centre, York University, Toronto, Ontario, Canada
- Key Laboratory of Adolescent Health Assessment and Exercise Intervention, Ministry of Education of China, Shanghai, China; and
- College of Physical Education and Health, East China Normal University, Shanghai, China
| | - Sobia Iqbal
- School of Kinesiology and Health Science, York University, Toronto, Ontario, Canada
- Muscle Health Research Centre, York University, Toronto, Ontario, Canada
| | - Michael F. N. O'Leary
- School of Kinesiology and Health Science, York University, Toronto, Ontario, Canada
- Muscle Health Research Centre, York University, Toronto, Ontario, Canada
| | - Keir J. Menzies
- Muscle Health Research Centre, York University, Toronto, Ontario, Canada
| | - Ayesha Saleem
- School of Kinesiology and Health Science, York University, Toronto, Ontario, Canada
- Muscle Health Research Centre, York University, Toronto, Ontario, Canada
| | - Shuzhe Ding
- Key Laboratory of Adolescent Health Assessment and Exercise Intervention, Ministry of Education of China, Shanghai, China; and
- College of Physical Education and Health, East China Normal University, Shanghai, China
| | - David A. Hood
- School of Kinesiology and Health Science, York University, Toronto, Ontario, Canada
- Muscle Health Research Centre, York University, Toronto, Ontario, Canada
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335
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Multiple mechanisms repress N-Bak mRNA translation in the healthy and apoptotic neurons. Cell Death Dis 2013; 4:e777. [PMID: 23969856 PMCID: PMC3763458 DOI: 10.1038/cddis.2013.297] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2013] [Revised: 06/28/2013] [Accepted: 07/04/2013] [Indexed: 11/29/2022]
Abstract
N-Bak is a neuron-specific BH3-only splice variant of pro-apoptotic Bcl-2 family member Bak. We have shown that its mRNA is stable in the neurons, whereas the protein cannot be detected by antibodies, suggesting a strong translational arrest of the mRNA. Here we identify two regulatory elements in the N-Bak mRNA that significantly repress translation in the luciferase reporter assay: an upstream open reading frame in the 5′-untranslated region (UTR) and naturally spliced exon–exon junction downstream of the premature translation termination codon in the 3′UTR. We also show that N-Bak mRNA is stored in granular structures in the sympathetic neurons and stays in these granules during intrinsic apoptosis. Finally, we confirm the absence of N-Bak protein by quantitative mass spectrometry analysis in the healthy, apoptotic or stressed sympathetic and cortical neurons. We conclude that N-Bak mRNA is translationally repressed by multiple mechanisms, and the protein does not participate in the classical apoptosis or cellular stress response.
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336
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Kim MS, Bak Y, Park YS, Lee DH, Kim JH, Kang JW, Song HH, Oh SR, Yoon DY. Wogonin induces apoptosis by suppressing E6 and E7 expressions and activating intrinsic signaling pathways in HPV-16 cervical cancer cells. Cell Biol Toxicol 2013; 29:259-72. [PMID: 23955116 DOI: 10.1007/s10565-013-9251-4] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2012] [Accepted: 07/22/2013] [Indexed: 01/14/2023]
Abstract
Wogonin is a flavonoid compound extracted from Scutellaria baicalensis and is well known as a benzodiazepine receptor ligand with anxiolytic effects. Many recent studies have demonstrated that wogonin modulates angiogenesis, proliferation, invasion, and tumor progress in various cancer tissues. We further explored the mechanism of action of wogonin on cervical cancer cells that contain or lack human papillomavirus (HPV) DNA. Wogonin was cytotoxic to HPV 16 (+) cervical cancer cells, SiHa and CaSki, but not to HPV-negative cells. We demonstrated that wogonin induced apoptosis by suppressing the expressions of the E6 and E7 viral oncogenes in HPV-infected cervical cancer CaSki and SiHa cells. The modulation of p53 and protein retinoblastoma (pRb) were also triggered by the suppression of E6 and E7 expressions. However, p53 was not altered in HPV-negative cervical cancer C33A cells. Moreover, wogonin modulated the mitochondrial membrane potential and the expression of pro- and anti-apoptotic factors such as Bax and Bcl-2. Wogonin also provoked the cleavage of caspase-3, caspase-9, and poly ADP ribose polymerase. After transfection of siRNAs to target E6 and E7, additional restoration of p53 and pRb was not induced, but processing of caspases and PARP was increased compared with wogonin treatment alone. Together, our findings demonstrated that wogonin effectively promotes apoptosis by downregulating E6 and E7 expressions and promoting intrinsic apoptosis in human cervical cancer cells.
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Affiliation(s)
- Man Sub Kim
- Department of Bioscience and Biotechnology, Bio/Molecular Informatics Center, Konkuk University, 1 Hwayang-dong, Gwangjin-gu, Seoul, 143-701, Republic of Korea
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Simultaneous knock-down of Bcl-xL and Mcl-1 induces apoptosis through Bax activation in pancreatic cancer cells. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2013; 1833:2980-2987. [PMID: 23954445 DOI: 10.1016/j.bbamcr.2013.08.006] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2012] [Revised: 07/29/2013] [Accepted: 08/06/2013] [Indexed: 11/20/2022]
Abstract
Anti-apoptotic Bcl-2 family proteins have been reported to play an important role in apoptotic cell death of human malignancies. The aim of this study was to delineate the mechanism of anti-apoptotic Bcl-2 family proteins in pancreatic cancer (PaCa) cell survival. We first analyzed the endogenous expression and subcellular localization of anti-apoptotic Bcl-2 family proteins in six PaCa cell lines by Western blot. To delineate the functional role of Bcl-2 family proteins, siRNA-mediated knock-down of protein expression was used. Apoptosis was measured by Cell Death ELISA and Hoechst 33258 staining. In the results, the expression of anti-apoptotic Bcl-2 family proteins varied between PaCa cell lines. Mcl-1 knock-down resulted in marked cleavage of PARP and induction of apoptosis. Down-regulation of Bcl-2 or Bcl-xL had a much weaker effect. Simultaneous knock-down of Bcl-xL and Mcl-1 strongly induced apoptosis, but simultaneous knock-down of Bcl-xL/Bcl-2 or Mcl-1/Bcl-2 had no additive effect. The apoptosis-inducing effect of simultaneous knock-down of Bcl-xL and Mcl-1 was associated with translocation of Bax from the cytosol to the mitochondrial membrane, cytochrome c release, and caspase activation. These results demonstrated that Bcl-xL and Mcl-1 play an important role in pancreatic cancer cell survival. Targeting both Bcl-xL and Mcl-1 may be an intriguing therapeutic strategy in PaCa.
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338
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Lipopolysaccharide-induced toll-like receptor 4 signaling in cancer cells promotes cell survival and proliferation in hepatocellular carcinoma. Dig Dis Sci 2013; 58:2223-36. [PMID: 23828139 DOI: 10.1007/s10620-013-2745-3] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/15/2012] [Accepted: 06/03/2013] [Indexed: 02/07/2023]
Abstract
BACKGROUND Recent studies have shown that toll-like receptor 4 (TLR4) is involved in hepatocarcinogenesis. However, the significance of TLR4 signaling in cancer development and progression remains unclear. AIM The purpose of this study was to investigate the role of TLR4 in cancer cell survival and proliferation in hepatocellular carcinoma (HCC). METHODS Fifty-three HCC and ten normal liver specimens were analyzed by immunohistochemistry, and three cell lines (HL-7702, PLC/PRF/5 and HepG2) were used for in vitro studies. Lipopolysaccharide (LPS), a specific ligand of TLR4, was used to activate TLR4 signaling. The effects of LPS-TLR4 signaling on cell survival, proliferation and invasion were examined. Specific inhibitors of NF-κB and MAPK (JNK, ERK and p38) signaling pathways were used to explore the role of each pathway in LPS-TLR4 signaling. RESULTS TLR4 was overexpressed in HCC cell lines and in human HCC tissues, where it correlated with Ki-67 expression. LPS-induced activation of TLR4 signaling promoted cancer cell survival and proliferation. LPS-TLR4 signaling was associated with regulation on the activation of NF-κB and MAPK signaling pathways. LPS-TLR4-induced activation of ERK and JNK signaling promotes cell proliferation through regulating Bax translocation to mitochondria. Activation of NF-κB and p38 mediates cytotoxicity of LPS, and inhibition on these two pathways promotes cell proliferation in HCC cells. CONCLUSION Our results indicate that TLR4 signaling in cancer cells promotes cell survival and proliferation in HCC.
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Nishiwaki Y, Yoshizawa A, Kojima Y, Oguri E, Nakamura S, Suzuki S, Yuasa-Kawada J, Kinoshita-Kawada M, Mochizuki T, Masai I. The BH3-only SNARE BNip1 mediates photoreceptor apoptosis in response to vesicular fusion defects. Dev Cell 2013; 25:374-87. [PMID: 23725763 DOI: 10.1016/j.devcel.2013.04.015] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2012] [Revised: 03/15/2013] [Accepted: 04/27/2013] [Indexed: 11/25/2022]
Abstract
Intracellular vesicular transport is important for photoreceptor function and maintenance. However, the mechanism underlying photoreceptor degeneration in response to vesicular transport defects is unknown. Here, we report that photoreceptors undergo apoptosis in a zebrafish β-soluble N-ethylmaleimide-sensitive factor attachment protein (β-SNAP) mutant. β-SNAP cooperates with N-ethylmaleimide-sensitive factor to recycle the SNAP receptor (SNARE), a key component of the membrane fusion machinery, by disassembling the cis-SNARE complex generated in the vesicular fusion process. We found that photoreceptor apoptosis in the β-SNAP mutant was dependent on the BH3-only protein BNip1. BNip1 functions as a component of the syntaxin-18 SNARE complex and regulates retrograde transport from the Golgi to the endoplasmic reticulum. Failure to disassemble the syntaxin-18 cis-SNARE complex caused BNip1-dependent apoptosis. These data suggest that the syntaxin-18 cis-SNARE complex functions as an alarm factor that monitors vesicular fusion competence and that BNip1 transforms vesicular fusion defects into photoreceptor apoptosis.
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Affiliation(s)
- Yuko Nishiwaki
- Developmental Neurobiology Unit, Okinawa Institute of Science and Technology Graduate University, 1919-1 Tancha, Onna, Okinawa 904-0412, Japan
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340
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Schulman JJ, Wright FA, Kaufmann T, Wojcikiewicz RJH. The Bcl-2 protein family member Bok binds to the coupling domain of inositol 1,4,5-trisphosphate receptors and protects them from proteolytic cleavage. J Biol Chem 2013; 288:25340-25349. [PMID: 23884412 DOI: 10.1074/jbc.m113.496570] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Bok is a member of the Bcl-2 protein family that controls intrinsic apoptosis. Bok is most closely related to the pro-apoptotic proteins Bak and Bax, but in contrast to Bak and Bax, very little is known about its cellular role. Here we report that Bok binds strongly and constitutively to inositol 1,4,5-trisphosphate receptors (IP3Rs), proteins that form tetrameric calcium channels in the endoplasmic reticulum (ER) membrane and govern the release of ER calcium stores. Bok binds most strongly to IP3R1 and IP3R2, and barely to IP3R3, and essentially all cellular Bok is IP3R bound in cells that express substantial amounts of IP3Rs. Binding to IP3Rs appears to be mediated by the putative BH4 domain of Bok and the docking site localizes to a small region within the coupling domain of IP3Rs (amino acids 1895-1903 of IP3R1) that is adjacent to numerous regulatory sites, including sites for proteolysis. With regard to the possible role of Bok-IP3R binding, the following was observed: (i) Bok does not appear to control the ability of IP3Rs to release ER calcium stores, (ii) Bok regulates IP3R expression, (iii) persistent activation of inositol 1,4,5-trisphosphate-dependent cell signaling causes Bok degradation by the ubiquitin-proteasome pathway, in a manner that parallels IP3R degradation, and (iv) Bok protects IP3Rs from proteolysis, either by chymotrypsin in vitro or by caspase-3 in vivo during apoptosis. Overall, these data show that Bok binds strongly and constitutively to IP3Rs and that the most significant consequence of this binding appears to be protection of IP3Rs from proteolysis. Thus, Bok may govern IP3R cleavage and activity during apoptosis.
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Affiliation(s)
- Jacqualyn J Schulman
- From the Department of Pharmacology, SUNY Upstate Medical University, Syracuse, New York 13210 and
| | - Forrest A Wright
- From the Department of Pharmacology, SUNY Upstate Medical University, Syracuse, New York 13210 and
| | - Thomas Kaufmann
- University of Bern, Medical Faculty, Institute of Pharmacology, Friedbuehlstrasse 49, CH-3010 Bern, Switzerland
| | - Richard J H Wojcikiewicz
- From the Department of Pharmacology, SUNY Upstate Medical University, Syracuse, New York 13210 and.
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341
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Juin P, Geneste O, Gautier F, Depil S, Campone M. Decoding and unlocking the BCL-2 dependency of cancer cells. Nat Rev Cancer 2013; 13:455-65. [PMID: 23783119 DOI: 10.1038/nrc3538] [Citation(s) in RCA: 170] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Cancer cells are subject to many apoptotic stimuli that would kill them were it not for compensatory prosurvival alterations. BCL-2-like (BCL-2L) proteins contribute to such aberrant behaviour by engaging a network of interactions that is potent at promoting survival but that is also fragile: inhibition of a restricted number of interactions may suffice to trigger cancer cell death. Currently available and novel compounds that inhibit these interactions could be efficient therapeutic agents if this phenotype of BCL-2L dependence was better understood at a molecular, cellular and systems level and if it could be diagnosed by relevant biomarkers.
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Affiliation(s)
- Philippe Juin
- Team 8 Cell survival and tumor escape in breast cancer, UMR 892 INSERM / 6299 CNRS / Université de Nantes, Institut de Recherche Thérapeutique de l'Université de Nantes, 8 quai Moncousu, BP 70721, 44007 Nantes Cedex, 1 France.
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342
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Tokar T, Turcan Z, Ulicny J. Boolean network-based model of the Bcl-2 family mediated MOMP regulation. Theor Biol Med Model 2013; 10:40. [PMID: 23767791 PMCID: PMC3716804 DOI: 10.1186/1742-4682-10-40] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2013] [Accepted: 05/30/2013] [Indexed: 01/05/2023] Open
Abstract
Background Mitochondrial outer membrane permeabilization (MOMP) is one of the most important points in the majority of apoptotic signaling cascades and it is controlled by a network of interactions between the members of the Bcl-2 family. Methods To understand the role of individual members of this family within the MOMP regulation, we have constructed a Boolean network-based model of interactions between the Bcl-2 proteins. Results Computational simulations have revealed the existence of trapping states which, independently from the incoming stimuli, block the occurrence of MOMP. Our results emphasize the role of the antiapoptotic protein Mcl-1 in the majority of these configurations. We demonstrate here the importance of the Bid and Bim for activation of effectors Bax and Bak, and the irreversibility of this activation. The model further points to the antiapoptotic protein Bcl-w as a key factor preventing Bax activation. Conclusions In spite of relative simplicity, the Boolean network-based model provides useful insight into main functioning logic of the Bcl-2 switch, consistent with experimental findings.
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Affiliation(s)
- Tomas Tokar
- Department of Biophysics, University of PJ Safarik, Jesenna 5, 04001 Kosice, Slovakia
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343
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Song T, Xue Z, Zhang Z, Shen X, Li X. Pan-BH3 mimetic S1 exhibits broad-spectrum antitumour effects by cooperation between Bax and Bak. Basic Clin Pharmacol Toxicol 2013; 113:145-51. [PMID: 23557083 DOI: 10.1111/bcpt.12074] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2013] [Accepted: 03/18/2013] [Indexed: 11/28/2022]
Abstract
Small molecule S1 is a pan-BH3 mimetic that can bind antiapoptotic Bcl-2, Bcl-xL and Mcl-1 proteins. Herein, different Bcl-2 member expression cancer cell lines (NCI-H345, MCF-7, SMMC-7721 and Hela) and cells deficient in Bax and/or Bak by shRNA were used to unravel the cascade of events by which S1 promotes apoptosis compared with Bcl-2/Bcl-xL inhibitor ABT-737. We identified that S1 exhibited broader antitumour spectrum than ABT-737 through disruption of more Bcl-2 interactions including Mcl-1/Bak interaction. Moreover, the individual and combined roles of Bax and Bak in S1-induced apoptosis were revealed. Our results showed that S1 induced a Bak-mediated apoptosis. Bak played a predominant role in either S1 or ABT-737-induced apoptosis through the cooperation with Bax on the formation of large oligomers on mitochondrial membrane.
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Affiliation(s)
- Ting Song
- State Key Laboratory of Fine Chemicals, School of Chemistry, Dalian University of Technology, Dalian, China
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344
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Webster KA. Mitochondrial membrane permeabilization and cell death during myocardial infarction: roles of calcium and reactive oxygen species. Future Cardiol 2013; 8:863-84. [PMID: 23176689 DOI: 10.2217/fca.12.58] [Citation(s) in RCA: 227] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Excess generation of reactive oxygen species (ROS) and cytosolic calcium accumulation play major roles in the initiation of programmed cell death during acute myocardial infarction. Cell death may include necrosis, apoptosis and autophagy, and combinations thereof. During ischemia, calcium handling between the sarcoplasmic reticulum and myofilament is disrupted and calcium is diverted to the mitochondria causing swelling. Reperfusion, while essential for survival, reactivates energy transduction and contractility and causes the release of ROS and additional ionic imbalance. During acute ischemia-reperfusion, the principal death pathways are programmed necrosis and apoptosis through the intrinsic pathway, initiated by the opening of the mitochondrial permeability transition pore and outer mitochondrial membrane permeabilization, respectively. Despite intense investigation, the mechanisms of action and modes of regulation of mitochondrial membrane permeabilization are incompletely understood. Extrinsic apoptosis, necroptosis and autophagy may also contribute to ischemia-reperfusion injury. In this review, the roles of dysregulated calcium and ROS and the contributions of Bcl-2 proteins, as well as mitochondrial morphology in promoting mitochondrial membrane permeability change and the ensuing cell death during myocardial infarction are discussed.
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Affiliation(s)
- Keith A Webster
- Department of Molecular & Cellular Pharmacology, University of Miami Medical Center, FL 33101, USA.
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345
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Moldoveanu T, Grace CR, Llambi F, Nourse A, Fitzgerald P, Gehring K, Kriwacki RW, Green DR. BID-induced structural changes in BAK promote apoptosis. Nat Struct Mol Biol 2013; 20:589-97. [PMID: 23604079 PMCID: PMC3683554 DOI: 10.1038/nsmb.2563] [Citation(s) in RCA: 154] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2012] [Accepted: 03/18/2013] [Indexed: 12/31/2022]
Abstract
The BCL-2 family protein BAK is responsible for mitochondrial outer membrane permeabilization (MOMP), which leads to apoptosis. The BCL-2 homology (BH) 3-only protein BID activates BAK to perform this function. We report the NMR solution structure of the human BID BH3–BAK complex, which identified the activation site at the canonical BH3-binding groove of BAK. Mutating the BAK BH1 in the groove prevented activation and MOMP but not the binding of BID. BAK BH3 mutations allowed BID binding and activation but blunted function by blocking BAK oligomerization. BAK activation follows a “hit-and-run” mechanism whereby BID dissociates from the trigger site allowing BAK oligomerization at an overlapping interface. In contrast, the BH3-only proteins NOXA and BAD are predicted to clash with the trigger site, and are not activators of BAK. These findings provide insights into the early stages of BAK activation.
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Affiliation(s)
- Tudor Moldoveanu
- Department of Immunology, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
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346
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Myc-induced AMPK-phospho p53 pathway activates Bak to sensitize mitochondrial apoptosis. Proc Natl Acad Sci U S A 2013; 110:E1839-48. [PMID: 23589839 DOI: 10.1073/pnas.1208530110] [Citation(s) in RCA: 108] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Oncogenic transcription factor Myc deregulates the cell cycle and simultaneously reprograms cellular metabolism to meet the biosynthetic and bioenergetic needs of proliferation. Myc also sensitizes cells to mitochondria-dependent apoptosis. Although metabolic reprogramming has been circumstantially connected to vulnerability to apoptosis, the connecting molecular pathways have remained poorly defined. Here, we show that Myc-induced altered glutamine metabolism involves ATP depletion and activation of the energy sensor AMP-activated protein kinase (AMPK), which induces stabilizing phosphorylation of p53 at Ser15. Under influence of Myc, AMPK-stabilized tumor suppressor protein p53 accumulates in the mitochondria and interacts with the protein complex comprised of B-cell lymphoma 2 (Bcl-2) antagonist/killer (BAK) and Bcl2-like 1 (Bcl-xL). Mitochondrial p53 induces conformational activation of proapoptotic Bak without disrupting the Bak-Bcl-xL interaction. Further liberation of Bak specifically from the p53-activated Bak-Bcl-xL complex leads to spontaneous oligomerization of Bak and apoptosis. Thus, Myc-induced metabolic changes are coupled via AMPK and phospho-p53 to the mitochondrial apoptosis effector Bak, demonstrating a cell-intrinsic mechanism to counteract uncontrolled proliferation.
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347
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Renault TT, Floros KV, Chipuk JE. BAK/BAX activation and cytochrome c release assays using isolated mitochondria. Methods 2013; 61:146-55. [PMID: 23567751 DOI: 10.1016/j.ymeth.2013.03.030] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2012] [Revised: 03/26/2013] [Accepted: 03/27/2013] [Indexed: 12/31/2022] Open
Abstract
The mitochondrial pathway of apoptosis proceeds when the outer mitochondrial membrane (OMM) is compromised by the pro-apoptotic BCL-2 family members, BAK and BAX. Once activated, BAK and BAX form proteolipid pores in the OMM leading to mitochondrial outer membrane permeabilization (MOMP), and the release of inner membrane space proteins, such as cytochrome c, which promotes caspase activation. The use of isolated mitochondria has been instrumental to understanding the key interactions necessary to engage BAK and BAX activation, MOMP, and apoptosis. Furthermore, it is possible to biochemically define the relationships between BCL-2 family function and mitochondrial physiology using isolated systems. Our laboratory uses freshly isolated mitochondria from numerous sources to better understand BCL-2 family function and requirements for BAK and BAX activation. Here, we will discuss commonly used in vitro techniques to perform MOMP and cytochrome c release assays; and provide several key methodologies to implicate BAK and BAX activity in these processes.
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Affiliation(s)
- Thibaud T Renault
- Icahn School of Medicine at Mount Sinai, Department of Oncological Sciences, One Gustave L. Levy Place, Box 1130, New York, NY 10029, USA
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Czabotar PE, Westphal D, Dewson G, Ma S, Hockings C, Fairlie WD, Lee EF, Yao S, Robin AY, Smith BJ, Huang DCS, Kluck RM, Adams JM, Colman PM. Bax crystal structures reveal how BH3 domains activate Bax and nucleate its oligomerization to induce apoptosis. Cell 2013; 152:519-31. [PMID: 23374347 DOI: 10.1016/j.cell.2012.12.031] [Citation(s) in RCA: 432] [Impact Index Per Article: 39.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2012] [Revised: 10/11/2012] [Accepted: 12/10/2012] [Indexed: 02/06/2023]
Abstract
In stressed cells, apoptosis ensues when Bcl-2 family members Bax or Bak oligomerize and permeabilize the mitochondrial outer membrane. Certain BH3-only relatives can directly activate them to mediate this pivotal, poorly understood step. To clarify the conformational changes that induce Bax oligomerization, we determined crystal structures of BaxΔC21 treated with detergents and BH3 peptides. The peptides bound the Bax canonical surface groove but, unlike their complexes with prosurvival relatives, dissociated Bax into two domains. The structures define the sequence signature of activator BH3 domains and reveal how they can activate Bax via its groove by favoring release of its BH3 domain. Furthermore, Bax helices α2-α5 alone adopted a symmetric homodimer structure, supporting the proposal that two Bax molecules insert their BH3 domain into each other's surface groove to nucleate oligomerization. A planar lipophilic surface on this homodimer may engage the membrane. Our results thus define critical Bax transitions toward apoptosis.
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Affiliation(s)
- Peter E Czabotar
- The Walter and Eliza Hall Institute of Medical Research, Melbourne, Victoria 3052, Australia.
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349
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Fleming P, Kvansakul M, Voigt V, Kile BT, Kluck RM, Huang DCS, Degli-Esposti MA, Andoniou CE. MCMV-mediated inhibition of the pro-apoptotic Bak protein is required for optimal in vivo replication. PLoS Pathog 2013; 9:e1003192. [PMID: 23468630 PMCID: PMC3585157 DOI: 10.1371/journal.ppat.1003192] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2012] [Accepted: 12/28/2012] [Indexed: 01/29/2023] Open
Abstract
Successful replication and transmission of large DNA viruses such as the cytomegaloviruses (CMV) family of viruses depends on the ability to interfere with multiple aspects of the host immune response. Apoptosis functions as a host innate defence mechanism against viral infection, and the capacity to interfere with this process is essential for the replication of many viruses. The Bcl-2 family of proteins are the principle regulators of apoptosis, with two pro-apoptotic members, Bax and Bak, essential for apoptosis to proceed. The m38.5 protein encoded by murine CMV (MCMV) has been identified as Bax-specific inhibitor of apoptosis. Recently, m41.1, a protein product encoded by the m41 open reading frame (ORF) of MCMV, has been shown to inhibit Bak activity in vitro. Here we show that m41.1 is critical for optimal MCMV replication in vivo. Growth of a m41.1 mutant was attenuated in multiple organs, a defect that was not apparent in Bak−/− mice. Thus, m41.1 promotes MCMV replication by inhibiting Bak-dependent apoptosis during in vivo infection. The results show that Bax and Bak mediate non-redundant functions during MCMV infection and that the virus produces distinct inhibitors for each protein to counter the activity of these proteins. The cytomegaloviruses (CMV) are a family of viruses that establish a latent infection that lasts for the life of the host, with the virus able to reactivate when the host is immunosuppressed. We have used murine CMV (MCMV) as a model to understand how CMV interferes with the anti-viral immune response. Apoptosis, or programmed cell death, is one of the defence mechanisms used by multicellular organisms to impair viral infection. In order for viral replication to proceed, many viruses have evolved mechanisms to prevent the apoptosis of infected host cells. Under most circumstances the activation of Bax, or the closely related protein Bak, is required for apoptosis to proceed. The m41.1 protein was recently identified as a candidate Bak inhibitor during in vitro infection. We have generated a mutant virus which is unable to produce the m41.1 protein and found that growth of this virus was attenuated in wild-type mice. Importantly, growth of the mutant virus was equivalent to that of the wild-type virus in mice lacking the Bak protein. These studies establish that m41.1 is an inhibitor of Bak and that the capacity to prevent apoptosis triggered by Bak is required for efficient replication of MCMV in vivo.
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Affiliation(s)
- Peter Fleming
- Immunology and Virology Program, Centre for Ophthalmology and Visual Science, The University of Western Australia, Nedlands, Western Australia, Australia
- Centre for Experimental Immunology, Lions Eye Institute, Nedlands, Western Australia, Australia
| | - Marc Kvansakul
- Department of Biochemistry, La Trobe University, Melbourne, Victoria, Australia
| | - Valentina Voigt
- Immunology and Virology Program, Centre for Ophthalmology and Visual Science, The University of Western Australia, Nedlands, Western Australia, Australia
- Centre for Experimental Immunology, Lions Eye Institute, Nedlands, Western Australia, Australia
| | - Benjamin T. Kile
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
- Department of Medical Biology, University of Melbourne, Melbourne, Victoria, Australia
| | - Ruth M. Kluck
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
- Department of Medical Biology, University of Melbourne, Melbourne, Victoria, Australia
| | - David C. S. Huang
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
- Department of Medical Biology, University of Melbourne, Melbourne, Victoria, Australia
| | - Mariapia A. Degli-Esposti
- Immunology and Virology Program, Centre for Ophthalmology and Visual Science, The University of Western Australia, Nedlands, Western Australia, Australia
- Centre for Experimental Immunology, Lions Eye Institute, Nedlands, Western Australia, Australia
| | - Christopher E. Andoniou
- Immunology and Virology Program, Centre for Ophthalmology and Visual Science, The University of Western Australia, Nedlands, Western Australia, Australia
- Centre for Experimental Immunology, Lions Eye Institute, Nedlands, Western Australia, Australia
- * E-mail:
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350
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Piedfer M, Bouchet S, Tang R, Billard C, Dauzonne D, Bauvois B. p70S6 kinase is a target of the novel proteasome inhibitor 3,3'-diamino-4'-methoxyflavone during apoptosis in human myeloid tumor cells. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2013; 1833:1316-28. [PMID: 23481040 DOI: 10.1016/j.bbamcr.2013.02.016] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2012] [Revised: 01/17/2013] [Accepted: 02/15/2013] [Indexed: 12/01/2022]
Abstract
Acute myeloid leukemia (AML) is a deadly disease characterized by the clonal expansion and accumulation of hematopoietic stem cells arrested at various stages of development. Clinical research efforts are currently focusing on targeted therapies that induce apoptosis in AML cells. Herein, the effects and mechanisms of the novel flavone 3,3'-diamino-4'-methoxyflavone (DD1) on AML cell dysfunction were investigated in AML cells (monoblast U937, myelomonocyte OCI-AML3, promyelocyte NB4, myeloblast HL-60) and blood samples from patients with AML. The administration of DD1 inhibited proliferation and induced death of AML cell lines and reduced the clonogenic activity of AML, but not normal, blood cells. The flavone's apoptotic action in U937 cells was associated with recruitment of mitochondria, Bax activation, Bad dephosphorylation (at Ser(136)), activation of caspases -8, -9, and -3 and cleavage of the caspase substrate PARP-1. DD1 induced a marked decrease in (i) Thr(389)-phosphorylation and (ii) protein levels of the caspase-3 substrate P70 ribosomal S6 kinase (P70S6K, known for its ability to phosphorylate Bad). Caspase-dependent apoptosis and P70S6K degradation were simultaneously prevented by the caspase inhibitors. Importantly, DD1 was shown to directly inhibit the proteasome's chymotrypsin-like activity in U937 cells. Apoptotic activity of the proteasome inhibitor bortezomib was also related to Bax activation and P70S6K downregulation. Accordingly, DD1 failed to induce P70S6K cleavage, Bax stimulation and apoptosis in K562 cells resistant to bortezomib. These results indicate that DD1 has the potential to eradicate AML cells and support a critical role for Bax and P70S6K in DD1-mediated proteasome inhibition and apoptosis of leukemia cells.
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Affiliation(s)
- Marion Piedfer
- Université Pierre et Marie Curie, Université Paris-Descartes, Centre de Recherche des Cordeliers, Paris, France
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