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Bovan D, Krajnović T, Vuković NL, Vukić MD, Mijatović S, Tanić N, Arsenijević N, Maksimović-Ivanić D. Anoikis and cancer cell differentiation: novel modes of shikonin derivatives anticancer action in vitro. Mol Biol Rep 2024; 51:218. [PMID: 38281240 DOI: 10.1007/s11033-023-09093-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Accepted: 11/30/2023] [Indexed: 01/30/2024]
Abstract
BACKGROUND Shikonin is a naturally occurring naphthoquinone found in the roots of several genera of the Boraginaceae family, widely known for its numerous biological activities, such as antiinflammatory, antioxidant, antimicrobial and anticancer. In this study, the antitumor effect of six naphthoquinones isolated from the roots of Onosma visianii was evaluated using two cell lines, mouse melanoma B16 and highly aggressive rat glioma cell line C6. METHODS AND RESULTS All examined shikonins dose-dependently decreased the viability of tested cells, with compounds 5 and 6 being the most potent ones and hence subjected to further analysis. The diminished viability of B16 melanoma cells was in correlation with detected caspase-mediated apoptosis. Importantly, observed altered cell morphology along with the loss of dividing potential upon exposure to both shikonins implied reprogram of B16 cell phenotype. Elevated expression of myelin basic protein indicated the acquirement of Schwann-like cell phenotype, while detected autophagy might be connected to this phenomenon. On the contrary, upon exposure to both agents, C6 cells underwent specific cell death-anoikis, provoked by detachment from the extracellular matrix and compromised integrin signaling. Oppositely to compound 5, compound 6 realized anoikis in a caspase-independent manner and under sustained ERK1/2 activation, indicating the deviation from standard proanoikis signaling. CONCLUSIONS Herein, we have pointed out the diversity and novelty in the mode of action of shikonin derivatives depending on the tumor cell features, which represents a good platform for new investigations of these promising natural compounds.
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Affiliation(s)
- Dijana Bovan
- Department of Immunology, Institute for Biological Research "Siniša Stanković", National Institute of the Republic of Serbia, University of Belgrade, Bulevar despota Stefana 142, 11108, Belgrade, Serbia
| | - Tamara Krajnović
- Department of Immunology, Institute for Biological Research "Siniša Stanković", National Institute of the Republic of Serbia, University of Belgrade, Bulevar despota Stefana 142, 11108, Belgrade, Serbia
| | - Nenad L Vuković
- Department of Chemistry, Faculty of Science, University of Kragujevac, Radoja Domanovića 12, 34000, Kragujevac, Serbia
| | - Milena D Vukić
- Department of Chemistry, Faculty of Science, University of Kragujevac, Radoja Domanovića 12, 34000, Kragujevac, Serbia
| | - Sanja Mijatović
- Department of Immunology, Institute for Biological Research "Siniša Stanković", National Institute of the Republic of Serbia, University of Belgrade, Bulevar despota Stefana 142, 11108, Belgrade, Serbia
| | - Nikola Tanić
- Department of Neurobiology, Institute for Biological Research "Siniša Stanković", National Institute of the Republic of Serbia, University of Belgrade, Bulevar despota Stefana 142, 11108, Belgrade, Serbia
| | - Nebojša Arsenijević
- Center for Molecular Medicine and Stem Cell Research, Faculty of Medical Sciences, University of Kragujevac, Svetozara Markovića 69, 34000, Kragujevac, Serbia
| | - Danijela Maksimović-Ivanić
- Department of Immunology, Institute for Biological Research "Siniša Stanković", National Institute of the Republic of Serbia, University of Belgrade, Bulevar despota Stefana 142, 11108, Belgrade, Serbia.
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Roberts JZ, Crawford N, Longley DB. The role of Ubiquitination in Apoptosis and Necroptosis. Cell Death Differ 2021; 29:272-284. [PMID: 34912054 PMCID: PMC8817035 DOI: 10.1038/s41418-021-00922-9] [Citation(s) in RCA: 84] [Impact Index Per Article: 28.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Revised: 12/03/2021] [Accepted: 12/03/2021] [Indexed: 12/29/2022] Open
Abstract
Cell death pathways have evolved to maintain tissue homoeostasis and eliminate potentially harmful cells from within an organism, such as cells with damaged DNA that could lead to cancer. Apoptosis, known to eliminate cells in a predominantly non-inflammatory manner, is controlled by two main branches, the intrinsic and extrinsic apoptotic pathways. While the intrinsic pathway is regulated by the Bcl-2 family members, the extrinsic pathway is controlled by the Death receptors, members of the tumour necrosis factor (TNF) receptor superfamily. Death receptors can also activate a pro-inflammatory type of cell death, necroptosis, when Caspase-8 is inhibited. Apoptotic pathways are known to be tightly regulated by post-translational modifications, especially by ubiquitination. This review discusses research on ubiquitination-mediated regulation of apoptotic signalling. Additionally, the emerging importance of ubiquitination in regulating necroptosis is discussed.
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Affiliation(s)
- Jamie Z Roberts
- The Patrick G Johnston Centre for Cancer Research, Queen's University Belfast, Belfast, UK.
| | - Nyree Crawford
- Almac Discovery Laboratories, Health Sciences Building, Queen's University Belfast, Belfast, UK
| | - Daniel B Longley
- The Patrick G Johnston Centre for Cancer Research, Queen's University Belfast, Belfast, UK.
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3
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Gupta I, Singh K, Varshney NK, Khan S. Delineating Crosstalk Mechanisms of the Ubiquitin Proteasome System That Regulate Apoptosis. Front Cell Dev Biol 2018; 6:11. [PMID: 29479529 PMCID: PMC5811474 DOI: 10.3389/fcell.2018.00011] [Citation(s) in RCA: 62] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2017] [Accepted: 01/26/2018] [Indexed: 01/10/2023] Open
Abstract
Regulatory functions of the ubiquitin-proteasome system (UPS) are exercised mainly by the ubiquitin ligases and deubiquitinating enzymes. Degradation of apoptotic proteins by UPS is central to the maintenance of cell health, and deregulation of this process is associated with several diseases including tumors, neurodegenerative disorders, diabetes, and inflammation. Therefore, it is the view that interrogating protein turnover in cells can offer a strategy for delineating disease-causing mechanistic perturbations and facilitate identification of drug targets. In this review, we are summarizing an overview to elucidate the updated knowledge on the molecular interplay between the apoptosis and UPS pathways. We have condensed around 100 enzymes of UPS machinery from the literature that ubiquitinates or deubiquitinates the apoptotic proteins and regulates the cell fate. We have also provided a detailed insight into how the UPS proteins are able to fine-tune the intrinsic, extrinsic, and p53-mediated apoptotic pathways to regulate cell survival or cell death. This review provides a comprehensive overview of the potential of UPS players as a drug target for cancer and other human disorders.
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Affiliation(s)
- Ishita Gupta
- Structural Immunology Group, International Centre for Genetic Engineering and Biotechnology, New Delhi, India.,Drug Discovery Research Centre, Translational Health Science and Technology Institute, Faridabad, India
| | - Kanika Singh
- Drug Discovery Research Centre, Translational Health Science and Technology Institute, Faridabad, India
| | - Nishant K Varshney
- Drug Discovery Research Centre, Translational Health Science and Technology Institute, Faridabad, India
| | - Sameena Khan
- Drug Discovery Research Centre, Translational Health Science and Technology Institute, Faridabad, India
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Hata AN, Engelman JA, Faber AC. The BCL2 Family: Key Mediators of the Apoptotic Response to Targeted Anticancer Therapeutics. Cancer Discov 2015; 5:475-87. [PMID: 25895919 DOI: 10.1158/2159-8290.cd-15-0011] [Citation(s) in RCA: 435] [Impact Index Per Article: 48.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2015] [Accepted: 03/27/2015] [Indexed: 12/23/2022]
Abstract
UNLABELLED The ability of cancer cells to suppress apoptosis is critical for carcinogenesis. The BCL2 family proteins comprise the sentinel network that regulates the mitochondrial or intrinsic apoptotic response. Recent advances in our understanding of apoptotic signaling pathways have enabled methods to identify cancers that are "primed" to undergo apoptosis, and have revealed potential biomarkers that may predict which cancers will undergo apoptosis in response to specific therapies. Complementary efforts have focused on developing novel drugs that directly target antiapoptotic BCL2 family proteins. In this review, we summarize the current knowledge of the role of BCL2 family members in cancer development and response to therapy, focusing on targeted therapeutics, recent progress in the development of apoptotic biomarkers, and therapeutic strategies designed to overcome deficiencies in apoptosis. SIGNIFICANCE Apoptosis, long known to be important for response to conventional cytotoxic chemotherapy, has more recently been shown to be essential for the efficacy of targeted therapies. Approaches that increase the likelihood of a cancer to undergo apoptosis following therapy may help improve targeted treatment strategies. Cancer Discov; 5(5); 475-87. ©2015 AACR.
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Affiliation(s)
- Aaron N Hata
- Massachusetts General Hospital Cancer Center, Charlestown, Massachusetts. Department of Medicine, Harvard Medical School, Boston, Massachusetts
| | - Jeffrey A Engelman
- Massachusetts General Hospital Cancer Center, Charlestown, Massachusetts. Department of Medicine, Harvard Medical School, Boston, Massachusetts.
| | - Anthony C Faber
- Virginia Commonwealth University Philips Institute for Oral Health Research, School of Dentistry and Massey Cancer Center, Richmond, Virginia.
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5
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Targeting Cdc20 as a novel cancer therapeutic strategy. Pharmacol Ther 2015; 151:141-51. [PMID: 25850036 DOI: 10.1016/j.pharmthera.2015.04.002] [Citation(s) in RCA: 172] [Impact Index Per Article: 19.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Accepted: 03/31/2015] [Indexed: 12/25/2022]
Abstract
The Anaphase Promoting Complex (APC, also called APC/C) regulates cell cycle progression by forming two closely related, but functionally distinct E3 ubiquitin ligase sub-complexes, APC(Cdc20) and APC(Cdh1), respectively. Emerging evidence has begun to reveal that Cdc20 and Cdh1 have opposing functions in tumorigenesis. Specifically, Cdh1 functions largely as a tumor suppressor, whereas Cdc20 exhibits an oncogenic function, suggesting that Cdc20 could be a promising therapeutic target for combating human cancer. However, the exact underlying molecular mechanisms accounting for their differences in tumorigenesis remain largely unknown. Therefore, in this review, we summarize the downstream substrates of Cdc20 and the critical functions of Cdc20 in cell cycle progression, apoptosis, ciliary disassembly and brain development. Moreover, we briefly describe the upstream regulators of Cdc20 and the oncogenic role of Cdc20 in a variety of human malignancies. Furthermore, we summarize multiple pharmacological Cdc20 inhibitors including TAME and Apcin, and their potential clinical benefits. Taken together, development of specific Cdc20 inhibitors could be a novel strategy for the treatment of human cancers with elevated Cdc20 expression.
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Ma W, Zhang D, Zheng L, Zhan Y, Zhang Y. Potential roles of Centipede Scolopendra extracts as a strategy against EGFR-dependent cancers. Am J Transl Res 2015; 7:39-52. [PMID: 25755827 PMCID: PMC4346522] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2014] [Accepted: 11/25/2014] [Indexed: 06/04/2023]
Abstract
Centipede Scolopendra, a commonly used traditional Chinese medicine, has been shown to have anti-cancer effects. In this study, the inhibitory effect of alcohol extracts of Centipede Scolopendra (AECS) was more prominent when treating cells highly expressing epidermal growth factor receptor (EGFR) (A431 and HEK293/EGFR cells versus HEK293 cells). The elution profiles of AECS on cell membrane chromatography (CMC) column showed that AECS could bind to EGFR, and competition studies indicated that AECS and gefitinib may have direct competition at a single common binding site on EGFR. SiRNA knockdown of EGFR in A431 cells attenuated AECS effects, suggesting that EGFR was a target mediated by AECS. In a cell culture system, AECS dramatically induced apoptosis of A431 and HEK293/EGFR cells, which was associated with the effects on Bcl-2 family. Furthermore, AECS could alter EGFR kinase activity and reduce phosphorylation of EGFR and downstream signaling players AKT and Erk1/2. The mechanism of AECS to inhibit high-EGFR expression cell proliferation is due to its ability to induce apoptosis and modulate the EGFR pathway. This study might provide a novel therapy for cancer with high-EGFR expression.
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Affiliation(s)
- Weina Ma
- School of Pharmacy, Health Science Center, Xi'an Jiaotong University No. 76, Yanta Weststreet, #54, Xi'an, Shaanxi Province, P.R. China
| | - Dongdong Zhang
- School of Pharmacy, Health Science Center, Xi'an Jiaotong University No. 76, Yanta Weststreet, #54, Xi'an, Shaanxi Province, P.R. China
| | - Lei Zheng
- School of Pharmacy, Health Science Center, Xi'an Jiaotong University No. 76, Yanta Weststreet, #54, Xi'an, Shaanxi Province, P.R. China
| | - Yingzhuan Zhan
- School of Pharmacy, Health Science Center, Xi'an Jiaotong University No. 76, Yanta Weststreet, #54, Xi'an, Shaanxi Province, P.R. China
| | - Yanmin Zhang
- School of Pharmacy, Health Science Center, Xi'an Jiaotong University No. 76, Yanta Weststreet, #54, Xi'an, Shaanxi Province, P.R. China
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Abstract
BIM represents a BH3-only proapoptotic member of the BCL-2 family of apoptotic regulatory proteins. Recent evidence suggests that in addition to its involvement in normal homeostasis, BIM plays a critical role in tumor cell biology, including the regulation of tumorigenesis through activities as a tumor suppressor, tumor metastasis, and tumor cell survival. Consequently, BIM has become the focus of intense interest as a potential target for cancer chemotherapy. The control of BIM expression is complex, and involves multiple factors, including epigenetic events (i.e., promoter acetylation or methylation, miRNA), transcription factors, posttranscriptional regulation, and posttranslational modifications, most notably phosphorylation. Significantly, the expression of BIM by tumor cells has been shown to play an important role in determining the response of transformed cells to not only conventional cytotoxic agents, but also to a broad array of targeted agents that interrupt cell signaling and survival pathways. Furthermore, modifications in BIM expression may be exploited to improve the therapeutic activity and potentially the selectivity of such agents. It is likely that evolving insights into the factors that regulate BIM expression will ultimately lead to novel BIM-based therapeutic strategies in the future.
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Affiliation(s)
- Hisashi Harada
- Department of Oral and Craniofacial Molecular Biology, Massey Cancer Center, Virginia Commonwealth University Health Sciences System, Richmond VA, 23298, USA
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Akiyama T, Tanaka S. Bim: guardian of tissue homeostasis and critical regulator of the immune system, tumorigenesis and bone biology. Arch Immunol Ther Exp (Warsz) 2011; 59:277-87. [PMID: 21633919 DOI: 10.1007/s00005-011-0126-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2010] [Accepted: 01/11/2011] [Indexed: 12/16/2022]
Abstract
One of the most important roles of apoptosis is the maintenance of tissue homeostasis. Impairment of apoptosis leads to a number of pathological conditions. In response to apoptotic signals, various proteins are activated in a pathway and signal-specific manner. Recently, the pro-apoptotic molecule Bim has attracted increasing attention as a pivotal regulator of tissue homeostasis. The Bim expression level is strictly controlled in both transcriptional and post-transcriptional levels. This control is dependent on cell, tissue and apoptotic stimuli. The phenotype of Bim-deficient mice is a systemic lupus erythematosus-like autoimmune disease with an abnormal accumulation of hematopoietic cells. Bim is thus a critical regulator of hematopoietic cells and immune system. Further studies have revealed the critical roles of Bim in various normal and pathological conditions, including bone homeostasis and tumorigenesis. The current understanding of Bim signaling and roles in the maintenance of tissue homeostasis is reviewed in this paper, focusing on the immune system, bone biology and tumorigenesis to illustrate the diversified role of Bim.
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Affiliation(s)
- Toru Akiyama
- Department of Orthopaedic Surgery, Saitama Medical Center, Jichi Medical University, Omiya-ku, Saitama, Japan
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9
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Thompson S, Pearson AN, Ashley MD, Jessick V, Murphy BM, Gafken P, Henshall DC, Morris KT, Simon RP, Meller R. Identification of a novel Bcl-2-interacting mediator of cell death (Bim) E3 ligase, tripartite motif-containing protein 2 (TRIM2), and its role in rapid ischemic tolerance-induced neuroprotection. J Biol Chem 2011; 286:19331-9. [PMID: 21478148 DOI: 10.1074/jbc.m110.197707] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We have previously shown that the cell death-promoting protein Bcl-2-interacting mediator of cell death (Bim) is ubiquitinated and degraded following a neuroprotection-conferring episode of brief ischemia (preconditioning). Here, we identify the E3 ligase that ubiquitinates Bim in this model, using a proteomics approach. Using phosphorylated GST-Bim as bait, we precipitated and identified by mass spectrometry tripartite motif protein 2 (TRIM2), a RING (really interesting new gene) domain-containing protein. The reaction between TRIM2 and Bim was confirmed using co-immunoprecipitation followed by immunoblotting. We show that TRIM2 binds to Bim when it is phosphorylated by p42/p44 MAPK but does not interact with a nonphosphorylatable Bim mutant (3ABim). 12-O-tetradecanoylphorbol-13-acetate activation of p42/p44 MAPK drives Bim ubiquitination in mouse embryonic fibroblast cells and is associated with an increased interaction between TRIM2 and Bim. One hour following preconditioning ischemia, the binding of Bim to TRIM2 increased, consistent with the time window of enhanced Bim degradation. Blocking p42/p44 MAPK activation following preconditioning ischemia with U0126 or using the nonphosphorylatable 3ABim reduced the binding between Bim and TRIM2. Immunodepletion of TRIM2 from cell lysates prepared from preconditioned cells reduced Bim ubiquitination. Finally, suppression of TRIM2 expression, using lentivirus transduction of shRNAmir, stabilized Bim protein levels and blocked neuroprotection observed in rapid ischemic tolerance. Taken together, these data support a role for TRIM2 in mediating the p42/p44 MAPK-dependent ubiquitination of Bim in rapid ischemic tolerance.
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Affiliation(s)
- Simon Thompson
- Neuroscience Institute, Morehouse School of Medicine, Atlanta, Georgia 30310-1495, USA
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10
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Wiggins CM, Tsvetkov P, Johnson M, Joyce CL, Lamb CA, Bryant NJ, Komander D, Shaul Y, Cook SJ. BIMEL, an intrinsically disordered protein, is degraded by 20S proteasomes in the absence of poly-ubiquitylation. J Cell Sci 2011; 124:969-77. [DOI: 10.1242/jcs.058438] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
BIM-extra long (BIMEL), a pro-apoptotic BH3-only protein and part of the BCL-2 family, is degraded by the proteasome following activation of the ERK1/2 signalling pathway. Although studies have demonstrated poly-ubiquitylation of BIMEL in cells, the nature of the ubiquitin chain linkage has not been defined. Using ubiquitin-binding domains (UBDs) specific for defined ubiquitin chain linkages, we show that BIMEL undergoes K48-linked poly-ubiquitylation at either of two lysine residues. Surprisingly, BIMELΔKK, which lacks both lysine residues, was not poly-ubiquitylated but still underwent ERK1/2-driven, proteasome-dependent turnover. BIM has been proposed to be an intrinsically disordered protein (IDP) and some IDPs can be degraded by uncapped 20S proteasomes in the absence of poly-ubiquitylation. We show that BIMEL is degraded by isolated 20S proteasomes but that this is prevented when BIMEL is bound to its pro-survival target protein MCL-1. Furthermore, knockdown of the proteasome cap component Rpn2 does not prevent BIMEL turnover in cells, and inhibition of the E3 ubiquitin ligase β-TrCP, which catalyses poly-Ub of BIMEL, causes Cdc25A accumulation but does not inhibit BIMEL turnover. These results provide new insights into the regulation of BIMEL by defining a novel ubiquitin-independent pathway for the proteasome-dependent destruction of this highly toxic protein.
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Affiliation(s)
- Ceri M. Wiggins
- Laboratory of Molecular Signalling, The Babraham Institute, Babraham Research Campus, Cambridge, CB22 3AT, UK
| | - Peter Tsvetkov
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Mark Johnson
- Laboratory of Molecular Signalling, The Babraham Institute, Babraham Research Campus, Cambridge, CB22 3AT, UK
| | - Claire L. Joyce
- Laboratory of Molecular Signalling, The Babraham Institute, Babraham Research Campus, Cambridge, CB22 3AT, UK
| | - Christopher A. Lamb
- Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK
| | - Nia J. Bryant
- Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK
| | - David Komander
- MRC Laboratory of Molecular Biology, Hills Road, Cambridge CB2 0QH, UK
| | - Yosef Shaul
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Simon J. Cook
- Laboratory of Molecular Signalling, The Babraham Institute, Babraham Research Campus, Cambridge, CB22 3AT, UK
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Rubert J, Qian Z, Andraos R, Guthy DA, Radimerski T. Bim and Mcl-1 exert key roles in regulating JAK2V617F cell survival. BMC Cancer 2011; 11:24. [PMID: 21247487 PMCID: PMC3037340 DOI: 10.1186/1471-2407-11-24] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2010] [Accepted: 01/19/2011] [Indexed: 01/12/2023] Open
Abstract
Background The JAK2V617F mutation plays a major role in the pathogenesis of myeloproliferative neoplasms and is found in the vast majority of patients suffering from polycythemia vera and in roughly every second patient suffering from essential thrombocythemia or from primary myelofibrosis. The V617F mutation is thought to provide hematopoietic stem cells and myeloid progenitors with a survival and proliferation advantage. It has previously been shown that activated JAK2 promotes cell survival by upregulating the anti-apoptotic STAT5 target gene Bcl-xL. In this study, we have investigated the role of additional apoptotic players, the pro-apoptotic protein Bim as well as the anti-apoptotic protein Mcl-1. Methods Pharmacological inhibition of JAK2/STAT5 signaling in JAK2V617F mutant SET-2 and MB-02 cells was used to study effects on signaling, cell proliferation and apoptosis by Western blot analysis, WST-1 proliferation assays and flow cytometry. Cells were transfected with siRNA oligos to deplete candidate pro- and anti-apoptotic proteins. Co-immunoprecipitation assays were performed to assess the impact of JAK2 inhibition on complexes of pro- and anti-apoptotic proteins. Results Treatment of JAK2V617F mutant cell lines with a JAK2 inhibitor was found to trigger Bim activation. Furthermore, Bim depletion by RNAi suppressed JAK2 inhibitor-induced cell death. Bim activation following JAK2 inhibition led to enhanced sequestration of Mcl-1, besides Bcl-xL. Importantly, Mcl-1 depletion by RNAi was sufficient to compromise JAK2V617F mutant cell viability and sensitized the cells to JAK2 inhibition. Conclusions We conclude that Bim and Mcl-1 have key opposing roles in regulating JAK2V617F cell survival and propose that inactivation of aberrant JAK2 signaling leads to changes in Bim complexes that trigger cell death. Thus, further preclinical evaluation of combinations of JAK2 inhibitors with Bcl-2 family antagonists that also tackle Mcl-1, besides Bcl-xL, is warranted to assess the therapeutic potential for the treatment of chronic myeloproliferative neoplasms.
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Affiliation(s)
- Joëlle Rubert
- Disease Area Oncology, Novartis Institutes for BioMedical Research, Basel, Switzerland
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12
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Kurtulus S, Tripathi P, Opferman JT, Hildeman DA. Contracting the 'mus cells'--does down-sizing suit us for diving into the memory pool? Immunol Rev 2010; 236:54-67. [PMID: 20636808 PMCID: PMC2907539 DOI: 10.1111/j.1600-065x.2010.00920.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Maintenance of T-cell homeostasis is critical for normal functioning of the immune system. After thymocyte selection, T cells enter the peripheral lymphoid organs, where they are maintained as naive cells. Transient disruption of homeostasis occurs when naive T cells undergo antigen-driven expansion and acquire effector functions. Effector T cells then either undergo apoptosis (i.e. contraction at the population level) or survive to become memory cells. This apoptotic process is crucial: it resets T-cell homeostasis, promotes protective immunity, and limits autoimmunity. Although initial studies using in vitro models supported a role for death receptor signaling, more recent in vivo studies have implicated Bcl-2 family members as being critical for the culling of T-cell responses. While several Bcl-2 family members likely contribute to T-cell contraction, the pro-apoptotic molecule Bim and its anti-apoptotic antagonist Bcl-2 are essential regulators of the process. This review discusses the progress made in our understanding of the mechanisms underlying contraction of T-cell responses and how some cells avoid this cell death and become memory T cells.
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Affiliation(s)
- Sema Kurtulus
- Division of Immunobiology in the Department of Pediatrics at the University of Cincinnati and Children's Hospital Medical Center, Cincinnati, Ohio, USA
| | - Pulak Tripathi
- Division of Immunobiology in the Department of Pediatrics at the University of Cincinnati and Children's Hospital Medical Center, Cincinnati, Ohio, USA
| | - Joseph T. Opferman
- Department of Biochemistry at St. Jude Children's Research Hospital, Memphis, TN, USA
| | - David A. Hildeman
- Division of Immunobiology in the Department of Pediatrics at the University of Cincinnati and Children's Hospital Medical Center, Cincinnati, Ohio, USA
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13
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Wiggins CM, Johnson M, Cook SJ. Refining the minimal sequence required for ERK1/2-dependent poly-ubiquitination and proteasome-dependent turnover of BIM. Cell Signal 2010; 22:801-8. [DOI: 10.1016/j.cellsig.2010.01.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2009] [Revised: 01/03/2010] [Accepted: 01/05/2010] [Indexed: 12/23/2022]
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Akiyama T, Dass CR, Choong PFM. Bim-targeted cancer therapy: a link between drug action and underlying molecular changes. Mol Cancer Ther 2010; 8:3173-80. [PMID: 19934277 DOI: 10.1158/1535-7163.mct-09-0685] [Citation(s) in RCA: 116] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
In the past few years, the pro-apoptotic molecule Bim has attracted increasing attention as a plausible target for tumor therapy. A variety of normal and pathological systems regulated by Bim, dependent on cell type, apoptotic stimulation, and chemotherapeutic agents, have been documented. Bim promotes anoikis of many tumor cells, such as lung cancer, breast cancer, osteosarcoma, and melanoma. Various chemotherapeutic agents use Bim as a mediating executioner of cell death. Hence, Bim suppression supports metastasis and chemoresistance. Imatinib, gefitinib, bortezomib, and Bim protein itself are spotlighted as current and future Bim-targeting therapeutic agents. The potential benefits of Bim-targeted therapies are selectivity of treatment for tumor cells and reduction in tumor-associated phenomena such as chemoresistance and metastasis. Thus, Bim-targeting therapies may provide more effective and unique tumor management modalities in future. This review article discusses all these issues.
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Affiliation(s)
- Toru Akiyama
- Department of Orthopaedics, University of Melbourne, and St. Vincent's Hospital Melbourne, L3-Daly Wing, 35 Victoria Pde., Fitzroy, Melbourne, VIC 3065 Australia
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15
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Balmanno K, Chell SD, Gillings AS, Hayat S, Cook SJ. Intrinsic resistance to the MEK1/2 inhibitor AZD6244 (ARRY-142886) is associated with weak ERK1/2 signalling and/or strong PI3K signalling in colorectal cancer cell lines. Int J Cancer 2009; 125:2332-41. [PMID: 19637312 DOI: 10.1002/ijc.24604] [Citation(s) in RCA: 113] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Mutations in KRAS or BRAF frequently manifest in constitutive activation of the MEK1/2-ERK1/2 signalling pathway. The MEK1/2-selective inhibitor, AZD6244 (ARRY-142886), blocks ERK1/2 activation and is currently undergoing clinical evaluation. Tumour cells can vary markedly in their response to MAPK or ERK kinase (MEK) inhibitors, and the presence of a BRAF mutation is thought to predict sensitivity, with the RAS mutations being associated with intrinsic resistance. We analysed cell proliferation in a panel of 19 colorectal cancer cell lines and found no simple correlation between BRAF or KRAS mutation and sensitivity to AZD6244, though cells that harbour neither mutation tended to be resistant. Cells that were sensitive arrested in G(1) and/or underwent apoptosis and the presence of BRAF or KRAS mutation was not sufficient to predict either fate. Cell lines that were resistant to AZD6244 exhibited low or no ERK1/2 activation or exhibited coincident activation of ERK1/2 and protein kinase B (PKB), the latter indicative of activation of the PI3K pathway. In cell lines with coincident ERK1/2 and PKB activation, sensitivity to AZD6244 could be re-imposed by any of the 3 distinct PI3K/mTOR inhibitors. We conclude that AZD6244 is effective in colorectal cancer cell lines with BRAF or KRAS mutations. Sensitivity to MEK1/2 inhibition correlates with a biochemical signature; those cells with high ERK1/2 activity (whether mutant for BRAF or KRAS) evolve a dependency upon that pathway and tend to be sensitive to AZD6244 but this can be offset by high PI3K-dependent signalling. This may have implications for the use of MEK inhibitors in combination with PI3K inhibitors.
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Affiliation(s)
- Kathryn Balmanno
- Laboratory of Molecular Signalling, The Babraham Institute, Babraham Research Campus, Cambridge, England, United Kingdom
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Gillings AS, Balmanno K, Wiggins CM, Johnson M, Cook SJ. Apoptosis and autophagy: BIM as a mediator of tumour cell death in response to oncogene-targeted therapeutics. FEBS J 2009; 276:6050-62. [PMID: 19788418 DOI: 10.1111/j.1742-4658.2009.07329.x] [Citation(s) in RCA: 87] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The BCL-2 homology domain 3 (BH3)-only protein, B-cell lymphoma 2 interacting mediator of cell death (BIM) is a potent pro-apoptotic protein belonging to the B-cell lymphoma 2 protein family. In recent years, advances in basic biology have provided a clearer picture of how BIM kills cells and how BIM expression and activity are repressed by growth factor signalling pathways, especially the extracellular signal-regulated kinase 1/2 and protein kinase B pathways. In tumour cells these oncogene-regulated pathways are used to counter the effects of BIM, thereby promoting tumour cell survival. In parallel, a new generation of targeted therapeutics has been developed, which show remarkable specificity and efficacy in tumour cells that are addicted to particular oncogenes. It is now apparent that the expression and activation of BIM is a common response to these new therapeutics. Indeed, BIM has emerged from this marriage of basic and applied biology as an important mediator of tumour cell death in response to such drugs. The induction of BIM alone may not be sufficient for significant tumour cell death, as BIM is more likely to act in concert with other BH3-only proteins, or other death pathways, when new targeted therapeutics are used in combination with traditional chemotherapy agents. Here we discuss recent advances in understanding BIM regulation and review the role of BIM as a mediator of tumour cell death in response to novel oncogene-targeted therapeutics.
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Affiliation(s)
- Annette S Gillings
- Laboratory of Molecular Signalling, The Babraham Institute, Babraham Research Campus, Cambridge, UK
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Broemer M, Meier P. Ubiquitin-mediated regulation of apoptosis. Trends Cell Biol 2009; 19:130-40. [PMID: 19217783 DOI: 10.1016/j.tcb.2009.01.004] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2008] [Revised: 01/08/2009] [Accepted: 01/08/2009] [Indexed: 12/31/2022]
Abstract
Ubiquitin is a protein modifier that is conjugated to target proteins either as a single moiety or as polyubiquitin chains. Over the past several years, an increasing number of ubiquitin ligases and ubiquitin-deconjugating enzymes have been identified; these modulate cell survival by degradative and non-degradative means. Mutations that affect ubiquitin-mediated signalling are tightly linked to various human pathologies including tumorigenesis. Unravelling how the ubiquitin-signal is conjugated, edited and 'read' is crucial to understanding cellular processes such as endocytic trafficking, NF-kappaB signalling, gene expression, DNA repair and apoptosis. In this review, we summarize recent advances that start to elucidate how the ubiquitin message is used as a versatile tool to regulate apoptosis, for example in the conjugation of ubiquitin to caspases. This results in steric interference with substrate entry and allosteric conformational impairment of the catalytic pocket of the caspase.
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Affiliation(s)
- Meike Broemer
- The Breakthrough Toby Robins Breast Cancer Research Centre, Institute of Cancer Research, Mary-Jean Mitchell Green Building, Chester Beatty Laboratories, Fulham Road, London SW3 6JB, UK.
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betaTrCP- and Rsk1/2-mediated degradation of BimEL inhibits apoptosis. Mol Cell 2009; 33:109-16. [PMID: 19150432 PMCID: PMC2655121 DOI: 10.1016/j.molcel.2008.12.020] [Citation(s) in RCA: 150] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2008] [Revised: 12/02/2008] [Accepted: 12/17/2008] [Indexed: 11/23/2022]
Abstract
The BimEL tumor suppressor is a potent proapoptotic BH3-only protein. We found that, in response to survival signals, BimEL was rapidly phosphorylated on three serine residues in a conserved degron, facilitating binding and degradation via the F box protein betaTrCP. Phosphorylation of the BimEL degron was executed by Rsk1/2 and promoted by the Erk1/2-mediated phosphorylation of BimEL on Ser69. Compared to wild-type BimEL, a BimEL phosphorylation mutant unable to bind betaTrCP was stabilized and consequently potent at inducing apoptosis by the intrinsic mitochondrial pathway. Moreover, although non-small cell lung cancer (NSCLC) cells often become resistant to gefitinib (a clinically relevant tyrosine kinase inhibitor that induces apoptosis through BimEL), silencing of either betaTrCP or Rsk1/2 resulted in BimEL-mediated apoptosis of both gefitinib-sensitive and gefitinib-insensitive NSCLC cells. Our findings reveal that betaTrCP promotes cell survival in cooperation with the ERK-RSK pathway by targeting BimEL for degradation.
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Meller R. The role of the ubiquitin proteasome system in ischemia and ischemic tolerance. Neuroscientist 2009; 15:243-60. [PMID: 19181875 DOI: 10.1177/1073858408327809] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Ubiquitin modification targets a protein for rapid degradation by the proteasome. However, polyubiquitination of proteins can result in multiple functions depending on the topology of the ubiquitin chain. Therefore, ubiquitin signaling offers a more complex and versatile biology compared with many other posttranslational modifications. One area of potential for the application of this knowledge is the field of ischemia-induced brain damage, as occurs following a stroke. The ubiquitin proteasome system may exert a dual role on neuronal outcome following ischemia. Harmful ischemia results in an overload of the ubiquitin proteasome system, and blocking the proteasome reduces brain infarction following ischemia. However, the rapid and selective degradation of proteins following brief ischemia results in endogenous protection against ischemia. Therefore, further understanding of the molecular signaling mechanisms that regulate the ubiquitin proteasome system may reveal novel therapeutic targets to reduce brain damage when ischemia is predicted or reduce the activation of the cell death mechanisms and the inflammatory response following stroke. The aim of this review is to discuss some of the recent advances in the understanding of protein ubiquitination and its implications for novel stroke therapies.
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Affiliation(s)
- Robert Meller
- Legacy Clinical Research and Technology Center, Portland, Oregon, USA.
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Ramesh S, Wildey GM, Howe PH. Transforming growth factor beta (TGFbeta)-induced apoptosis: the rise & fall of Bim. Cell Cycle 2009; 8:11-7. [PMID: 19106608 DOI: 10.4161/cc.8.1.7291] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Transforming growth factor beta (TGFbeta) regulates essential cellular functions such as cellular proliferation, differentiation and apoptosis. Multiple apoptotic mediators and signaling pathways have been implicated in TGFbeta-induced apoptosis. Bim, a BH3-only protein, is critical for apoptosis in a variety of cell types. In resting cells, BimEL expression levels, the major and most abundant isoform, are controlled by Erk1/2-mediated phosphorylation, which targets BimEL for ubiquitination and degradation. We previously reported that TGFbeta induces the expression of the pro-apoptotic protein Bim through a Smad3-dependent mechanism to induce cell death in B-lymphocytes. A number of studies have shown TGFbeta to cause transcriptional induction of Bim in many cell types. Recently, we demonstrated that, in addition to its transcriptional effects on Bim, TGFbeta induces a MAPK phosphatase (MKP), MKP2/DUSP4, to rapidly increase BimEL levels by inactivation of Erk1/2, resulting in dephosphorylation and escape of BimEL from ubiquitin-mediated degradation. Our findings are of importance not only in the context that we implicate TGFbeta to increase BimEL levels through both an immediate post-translational regulatory mechanism and a long-term effect through transcriptional induction, but also in the context of implicating MKPs as regulatory players in apoptosis. Here we summarize these recent findings and their significance to our understanding of how TGFbeta mediates apoptosis, and we explore the possible regulatory mechanisms controlling Bim expression levels.
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Affiliation(s)
- Sneha Ramesh
- Department of Cancer Biology, Lerner Research Institute, Cleveland Clinic Foundation, 9500 Euclid Avenue, Cleveland, OH 44195, USA
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Regulation of osteoclast apoptosis by Bcl-2 family protein Bim and Caspase-3. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2009; 658:111-6. [PMID: 19950021 DOI: 10.1007/978-1-4419-1050-9_12] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Apopotosis of osteoclasts is regulated by the Bcl-2 family protein Bim. Bim is degraded in the course of osteoclast apoptosis, which is regulated by Caspase-3. Osteoclasts generated from caspase-3 -/- mice exhibited a shorter life span and a higher bone-resorbing activity than those generated from normal littermates. These results suggest the important role of Caspase-3-Bim axis in regulating both apoptosis and activation of osteoclasts.
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Balmanno K, Cook SJ. Tumour cell survival signalling by the ERK1/2 pathway. Cell Death Differ 2008; 16:368-77. [PMID: 18846109 DOI: 10.1038/cdd.2008.148] [Citation(s) in RCA: 366] [Impact Index Per Article: 22.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Several advances in recent years have focused increasing attention on the role of the RAF-MEK-ERK1/2 pathway in promoting cell survival. The demonstration that BRAF is a human oncogene mutated at high frequency in melanoma, thyroid and colon cancer has provided a pathophysiological context, whilst the description of potent and highly selective inhibitors of BRAF or MEK has allowed a more informed and rational intervention in both normal and tumour cells. In addition, separate studies have uncovered new mechanisms by which the ERK1/2 pathway can control the activity or abundance of members of the BCL-2 protein family to promote cell survival. It is now apparent that various oncogenes co-opt ERK1/2 signalling to de-regulate these BCL-2 proteins and this contributes to, and even underpins, survival signalling in some tumours. New oncogene-targeted therapies allow direct or indirect inhibition of ERK1/2 signalling and can cause quite striking tumour cell death. In other cases, inhibition of the ERK1/2 pathway may be more effective in combination with other conventional and novel therapeutics. Here, we review recent advances in our understanding of how the ERK1/2 pathway regulates BCL-2 proteins to promote survival, how this is de-regulated in tumour cells and the opportunities this might afford with the use of new targeted therapies.
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Affiliation(s)
- K Balmanno
- Laboratory of Molecular Signalling, The Babraham Institute, Babraham Research Campus, Cambridge CB22 3AT, UK.
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