1
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Wu D. Proapoptotic protein Bim regulates the suppressive function of Treg cells. J Zhejiang Univ Sci B 2023; 24:1180-1184. [PMID: 38057275 PMCID: PMC10710911 DOI: 10.1631/jzus.b2300288] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2023] [Accepted: 06/02/2023] [Indexed: 12/08/2023]
Abstract
Regulatory T (Treg) cells are a special immunosuppressive subset of cluster of differentiation 4-positive (CD4+)-T lymphocytes and play a pivotal role in the establishment of immune homeostasis in vivo (Zhang et al., 2021). The transcription factor forkhead box protein P3 (Foxp3) is the master marker of Treg cells, which is highly expressed in Treg cells and is also essential for their suppressive function (Hori et al., 2003). In addition to Foxp3, other regulators of Treg cells have been discovered (Wu et al., 2017, 2022; Wu and Sun, 2023a, 2023b); however, a deeper understanding of the regulation of these cells is required.
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Affiliation(s)
- Di Wu
- Cancer Institute (Key Laboratory of Cancer Prevention and Intervention, China National Ministry of Education), the Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou 310009, China.
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2
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Shanmuganad S, Hummel SA, Varghese V, Hildeman DA. Bcl-2 Is Necessary to Counteract Bim and Promote Survival of TCRαβ +CD8αα + Intraepithelial Lymphocyte Precursors in the Thymus. J Immunol 2022; 208:651-659. [PMID: 34996838 PMCID: PMC8982985 DOI: 10.4049/jimmunol.2100975] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Accepted: 11/16/2021] [Indexed: 02/03/2023]
Abstract
The precursors of TCRαβ+CD8αα+ intraepithelial lymphocytes (IEL) arise in the thymus through a complex process of agonist selection. We and others have shown that the proapoptotic protein, Bim, is critical to limit the number of thymic IEL precursors (IELp), as loss of Bim at the CD4+CD8+ double-positive stage of development drastically increases IELp. The factors determining this cell death versus survival decision remain largely unknown. In this study, we used CD4CreBcl2f/f mice to define the role of the antiapoptotic protein Bcl-2 and CD4CreBcl2f/fBimf/f mice to determine the role of Bcl-2 in opposing Bim to promote survival of IELp. First, in wild-type mice, we defined distinct subpopulations within PD-1+CD122+ IELp, based on their expression of Runx3 and α4β7. Coexpression of α4β7 and Runx3 marked IELp that were most dependent upon Bcl-2 for survival. Importantly, the additional loss of Bim restored Runx3+α4β7+ IELp, showing that Bcl-2 antagonizes Bim to enable IELp survival. Further, the loss of thymic IELp in CD4CreBcl2f/f mice also led to a dramatic loss of IEL in the gut, and the additional loss of Bim restored gut IEL. The loss of gut IEL was due to both reduced seeding by IELp from the thymus as well as a requirement for Bcl-2 for peripheral IEL survival. Together, these findings highlight subset-specific and temporal roles for Bcl-2 in driving the survival of TCRαβ+CD8αα+ IEL and thymic IELp.
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Affiliation(s)
- Sharmila Shanmuganad
- Immunology Graduate Program, Cincinnati Children's Hospital Medical Center and the University of Cincinnati College of Medicine, Cincinnati, OH; and
| | - Sarah A Hummel
- Division of Immunobiology, Cincinnati Children's Hospital Medical Center and the University of Cincinnati College of Medicine, Cincinnati, OH
| | - Vivian Varghese
- Division of Immunobiology, Cincinnati Children's Hospital Medical Center and the University of Cincinnati College of Medicine, Cincinnati, OH
| | - David A Hildeman
- Immunology Graduate Program, Cincinnati Children's Hospital Medical Center and the University of Cincinnati College of Medicine, Cincinnati, OH; and
- Division of Immunobiology, Cincinnati Children's Hospital Medical Center and the University of Cincinnati College of Medicine, Cincinnati, OH
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3
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Mohapatra S, Gupta V, Mondal P, Chatterjee S, Bhunia D, Ghosh S. A Small Molecule with Bridged Carbonyl and Tri-fluoro-aceto-phenone Groups Impedes Microtubule Dynamics and Subsequently Triggers Cancer Cell Apoptosis. ChemMedChem 2021; 16:2703-2714. [PMID: 33983670 DOI: 10.1002/cmdc.202100192] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Revised: 05/13/2021] [Indexed: 11/08/2022]
Abstract
We identified a new microtubule targeted small molecule, which showed significant anticancer activity and induced apoptotic death of cancer cells. Precisely the central bridged carbonyl group and trifluoro-acetophenone group of a bis-benzothiazole molecule (BBT) interacts with tubulin close to the curcumin site and perturbs microtubule dynamics as well as causes microtubule depolymerization. We observed a significant enhancement of fluorescence while BBT interacts with the tubulin through bridged carbonyl moiety, a similar phenomenon to colchicine. Further, BBT activates tumor-suppressing bim and p53-puma axes to inhibit cancer survival. It also shows promising results against a tumor spheroid model. BBT is also capable of tumor regression, which shows that this molecule can serve as a potential template for the design of next-generation microtubule targeted anticancer drugs.
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Affiliation(s)
- Saswat Mohapatra
- Department of Organic and Medicinal Chemistry Division, CSIR-Indian Institute of Chemical Biology, 4, Raja S. C. Mullick Road, Jadavpur, Kolkata, West Bengal, 700032, India
| | - Varsha Gupta
- Department of Organic and Medicinal Chemistry Division, CSIR-Indian Institute of Chemical Biology, 4, Raja S. C. Mullick Road, Jadavpur, Kolkata, West Bengal, 700032, India
| | - Prasenjit Mondal
- Department of Organic and Medicinal Chemistry Division, CSIR-Indian Institute of Chemical Biology, 4, Raja S. C. Mullick Road, Jadavpur, Kolkata, West Bengal, 700032, India
| | - Shreyam Chatterjee
- The Institute of Scientific and Industrial Research, Osaka University, 8-1, Mihogaoka, Ibaraki, Osaka, 567-0047, Japan
| | - Debmalya Bhunia
- Department of Organic and Medicinal Chemistry Division, CSIR-Indian Institute of Chemical Biology, 4, Raja S. C. Mullick Road, Jadavpur, Kolkata, West Bengal, 700032, India
| | - Surajit Ghosh
- Department of Bioscience & Bioengineering, Indian Institute of Technology Jodhpur, NH 62, Surpura Bypass Road, Karwar, Rajasthan, 342037, India.,Department of Organic and Medicinal Chemistry Division, CSIR-Indian Institute of Chemical Biology, 4, Raja S. C. Mullick Road, Jadavpur, Kolkata, West Bengal, 700032, India
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4
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Kabir S, Cidado J, Andersen C, Dick C, Lin PC, Mitros T, Ma H, Baik SH, Belmonte MA, Drew L, Corn JE. The CUL5 ubiquitin ligase complex mediates resistance to CDK9 and MCL1 inhibitors in lung cancer cells. eLife 2019; 8:44288. [PMID: 31294695 PMCID: PMC6701926 DOI: 10.7554/elife.44288] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2018] [Accepted: 07/05/2019] [Indexed: 12/22/2022] Open
Abstract
Overexpression of anti-apoptotic proteins MCL1 and Bcl-xL are frequently observed in many cancers. Inhibitors targeting MCL1 are in clinical development, however numerous cancer models are intrinsically resistant to this approach. To discover mechanisms underlying resistance to MCL1 inhibition, we performed multiple flow-cytometry based genome-wide CRISPR screens interrogating two drugs that directly (MCL1i) or indirectly (CDK9i) target MCL1. Remarkably, both screens identified three components (CUL5, RNF7 and UBE2F) of a cullin-RING ubiquitin ligase complex (CRL5) that resensitized cells to MCL1 inhibition. We find that levels of the BH3-only pro-apoptotic proteins Bim and Noxa are proteasomally regulated by the CRL5 complex. Accumulation of Noxa caused by depletion of CRL5 components was responsible for re-sensitization to CDK9 inhibitor, but not MCL1 inhibitor. Discovery of a novel role of CRL5 in apoptosis and resistance to multiple types of anticancer agents suggests the potential to improve combination treatments.
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Affiliation(s)
- Shaheen Kabir
- Innovative Genomics Institute, University of California, Berkeley, Berkeley, United States.,Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States.,Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, San Francisco, United States
| | - Justin Cidado
- Bioscience Oncology, IMED Biotech Unit, AstraZeneca, Waltham, United States
| | - Courtney Andersen
- Bioscience Oncology, IMED Biotech Unit, AstraZeneca, Waltham, United States
| | - Cortni Dick
- Bioscience Oncology, IMED Biotech Unit, AstraZeneca, Waltham, United States
| | - Pei-Chun Lin
- Innovative Genomics Institute, University of California, Berkeley, Berkeley, United States.,Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States
| | - Therese Mitros
- Innovative Genomics Institute, University of California, Berkeley, Berkeley, United States.,Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States
| | - Hong Ma
- Innovative Genomics Institute, University of California, Berkeley, Berkeley, United States.,Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States
| | - Seung Hyun Baik
- Innovative Genomics Institute, University of California, Berkeley, Berkeley, United States.,Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States
| | - Matthew A Belmonte
- Bioscience Oncology, IMED Biotech Unit, AstraZeneca, Waltham, United States
| | - Lisa Drew
- Bioscience Oncology, IMED Biotech Unit, AstraZeneca, Waltham, United States
| | - Jacob E Corn
- Innovative Genomics Institute, University of California, Berkeley, Berkeley, United States.,Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States
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5
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Zhang XQ, Dong JJ, Cai T, Shen X, Zhou XJ, Liao L. High glucose induces apoptosis via upregulation of Bim expression in proximal tubule epithelial cells. Oncotarget 2018; 8:24119-24129. [PMID: 28445931 PMCID: PMC5421832 DOI: 10.18632/oncotarget.15491] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2016] [Accepted: 02/02/2017] [Indexed: 02/04/2023] Open
Abstract
Diabetic nephropathy is the primary cause of end-stage renal disease. Apoptosis of tubule epithelial cells is a major feature of diabetic nephropathy. The mechanisms of high glucose (HG) induced apoptosis are not fully understood. Here we demonstrated that, HG induced apoptosis via upregulating the expression of proapoptotic Bcl-2 homology domain 3 (BH3)-only protein Bim protein, but not bring a significant change in the baseline level of autophagy in HK2 cells. The increase of Bim expression was caused by the ugregulation of transcription factors, FOXO1 and FOXO3a. Bim expression initiates BAX/BAK-mediated mitochondria-dependent apoptosis. Silence of Bim by siRNA in HK2 cells prevented HG-induced apoptosis and also sensitized HK2 cells to autophagy during HG treatment. The autophagy inhibitor 3-MA increased the injury in Bim knockdown HK2 cells by retriggering apoptosis. The above results suggest a Bim-independent apoptosis pathway in HK2 cells, which normally could be inhibited by autophagy. Overall, our results indicate that HG induces apoptosis via up-regulation of Bim expression in proximal tubule epithelial cells.
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Affiliation(s)
- Xiao-Qian Zhang
- Department of Endocrinology, Shandong Provincial Qianfoshan Hospital, Shandong University, Jinan, Shandong, China
| | - Jian-Jun Dong
- Department of Endocrinology, Qilu Hospital of Shandong University, Shandong, Jinan, China
| | - Tian Cai
- Department of Endocrinology, Shandong Provincial Qianfoshan Hospital, Shandong University of Traditional Chinese Medicine, Jinan, China.,Department of Medicine, Tai'an Hospital of Traditional Chinese Medicine, Tai'an, Shandong, China
| | - Xue Shen
- Department of Endocrinology, Shandong Provincial Qianfoshan Hospital, Shandong University of Traditional Chinese Medicine, Jinan, China
| | - Xiao-Jun Zhou
- Department of Endocrinology, Shandong Provincial Qianfoshan Hospital, Shandong University, Jinan, Shandong, China
| | - Lin Liao
- Department of Endocrinology, Shandong Provincial Qianfoshan Hospital, Shandong University, Jinan, Shandong, China
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6
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Song KA, Niederst MJ, Lochmann TL, Hata AN, Kitai H, Ham J, Floros KV, Hicks MA, Hu H, Mulvey HE, Drier Y, Heisey DAR, Hughes MT, Patel NU, Lockerman EL, Garcia A, Gillepsie S, Archibald HL, Gomez-Caraballo M, Nulton TJ, Windle BE, Piotrowska Z, Sahingur SE, Taylor SM, Dozmorov M, Sequist LV, Bernstein B, Ebi H, Engelman JA, Faber AC. Epithelial-to-Mesenchymal Transition Antagonizes Response to Targeted Therapies in Lung Cancer by Suppressing BIM. Clin Cancer Res 2018; 24:197-208. [PMID: 29051323 PMCID: PMC5959009 DOI: 10.1158/1078-0432.ccr-17-1577] [Citation(s) in RCA: 65] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2017] [Revised: 09/13/2017] [Accepted: 10/13/2017] [Indexed: 12/26/2022]
Abstract
Purpose: Epithelial-to-mesenchymal transition (EMT) confers resistance to a number of targeted therapies and chemotherapies. However, it has been unclear why EMT promotes resistance, thereby impairing progress to overcome it.Experimental Design: We have developed several models of EMT-mediated resistance to EGFR inhibitors (EGFRi) in EGFR-mutant lung cancers to evaluate a novel mechanism of EMT-mediated resistance.Results: We observed that mesenchymal EGFR-mutant lung cancers are resistant to EGFRi-induced apoptosis via insufficient expression of BIM, preventing cell death despite potent suppression of oncogenic signaling following EGFRi treatment. Mechanistically, we observed that the EMT transcription factor ZEB1 inhibits BIM expression by binding directly to the BIM promoter and repressing transcription. Derepression of BIM expression by depletion of ZEB1 or treatment with the BH3 mimetic ABT-263 to enhance "free" cellular BIM levels both led to resensitization of mesenchymal EGFR-mutant cancers to EGFRi. This relationship between EMT and loss of BIM is not restricted to EGFR-mutant lung cancers, as it was also observed in KRAS-mutant lung cancers and large datasets, including different cancer subtypes.Conclusions: Altogether, these data reveal a novel mechanistic link between EMT and resistance to lung cancer targeted therapies. Clin Cancer Res; 24(1); 197-208. ©2017 AACR.
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Affiliation(s)
- Kyung-A Song
- Philips Institute for Oral Health Research, VCU School of Dentistry and Massey Cancer Center, Richmond, Virginia
| | - Matthew J Niederst
- Massachusetts General Hospital Cancer Center, Boston, Massachusetts
- Department of Medicine, Harvard Medical School, Boston, Massachusetts
| | - Timothy L Lochmann
- Philips Institute for Oral Health Research, VCU School of Dentistry and Massey Cancer Center, Richmond, Virginia
| | - Aaron N Hata
- Massachusetts General Hospital Cancer Center, Boston, Massachusetts
- Department of Medicine, Harvard Medical School, Boston, Massachusetts
| | - Hidenori Kitai
- Division of Medical Oncology, Cancer Research Institute, Kanazawa University, Kanazawa, Japan
| | - Jungoh Ham
- Philips Institute for Oral Health Research, VCU School of Dentistry and Massey Cancer Center, Richmond, Virginia
| | - Konstantinos V Floros
- Philips Institute for Oral Health Research, VCU School of Dentistry and Massey Cancer Center, Richmond, Virginia
| | - Mark A Hicks
- Philips Institute for Oral Health Research, VCU School of Dentistry and Massey Cancer Center, Richmond, Virginia
| | - Haichuan Hu
- Massachusetts General Hospital Cancer Center, Boston, Massachusetts
- Department of Medicine, Harvard Medical School, Boston, Massachusetts
| | - Hillary E Mulvey
- Massachusetts General Hospital Cancer Center, Boston, Massachusetts
- Department of Medicine, Harvard Medical School, Boston, Massachusetts
| | - Yotam Drier
- Massachusetts General Hospital Cancer Center, Boston, Massachusetts
- Department of Medicine, Harvard Medical School, Boston, Massachusetts
| | - Daniel A R Heisey
- Philips Institute for Oral Health Research, VCU School of Dentistry and Massey Cancer Center, Richmond, Virginia
| | - Mark T Hughes
- Philips Institute for Oral Health Research, VCU School of Dentistry and Massey Cancer Center, Richmond, Virginia
| | - Neha U Patel
- Philips Institute for Oral Health Research, VCU School of Dentistry and Massey Cancer Center, Richmond, Virginia
| | - Elizabeth L Lockerman
- Massachusetts General Hospital Cancer Center, Boston, Massachusetts
- Department of Medicine, Harvard Medical School, Boston, Massachusetts
| | - Angel Garcia
- Massachusetts General Hospital Cancer Center, Boston, Massachusetts
- Department of Medicine, Harvard Medical School, Boston, Massachusetts
| | - Shawn Gillepsie
- Massachusetts General Hospital Cancer Center, Boston, Massachusetts
- Department of Medicine, Harvard Medical School, Boston, Massachusetts
| | - Hannah L Archibald
- Massachusetts General Hospital Cancer Center, Boston, Massachusetts
- Department of Medicine, Harvard Medical School, Boston, Massachusetts
| | - Maria Gomez-Caraballo
- Massachusetts General Hospital Cancer Center, Boston, Massachusetts
- Department of Medicine, Harvard Medical School, Boston, Massachusetts
| | - Tara J Nulton
- Philips Institute for Oral Health Research, VCU School of Dentistry and Massey Cancer Center, Richmond, Virginia
| | - Brad E Windle
- Philips Institute for Oral Health Research, VCU School of Dentistry and Massey Cancer Center, Richmond, Virginia
| | - Zofia Piotrowska
- Massachusetts General Hospital Cancer Center, Boston, Massachusetts
- Department of Medicine, Harvard Medical School, Boston, Massachusetts
| | - Sinem E Sahingur
- Department of Periodontics, VCU School of Dentistry, Virginia Commonwealth University, Richmond, Virginia
| | - Shirley M Taylor
- Department of Microbiology and Immunology, Massey Cancer Center, Richmond, Virginia
| | - Mikhail Dozmorov
- Department of Biostatistics, Virginia Commonwealth University, Richmond, Virginia
| | - Lecia V Sequist
- Massachusetts General Hospital Cancer Center, Boston, Massachusetts
- Department of Medicine, Harvard Medical School, Boston, Massachusetts
| | - Bradley Bernstein
- Massachusetts General Hospital Cancer Center, Boston, Massachusetts
- Department of Medicine, Harvard Medical School, Boston, Massachusetts
| | - Hiromichi Ebi
- Division of Medical Oncology, Cancer Research Institute, Kanazawa University, Kanazawa, Japan
| | - Jeffrey A Engelman
- Massachusetts General Hospital Cancer Center, Boston, Massachusetts.
- Department of Medicine, Harvard Medical School, Boston, Massachusetts
| | - Anthony C Faber
- Philips Institute for Oral Health Research, VCU School of Dentistry and Massey Cancer Center, Richmond, Virginia.
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7
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Bodur C, Karakas B, Timucin AC, Tezil T, Basaga H. AMP-activated protein kinase couples 3-bromopyruvate-induced energy depletion to apoptosis via activation of FoxO3a and upregulation of proapoptotic Bcl-2 proteins. Mol Carcinog 2015; 55:1584-1597. [PMID: 26373689 DOI: 10.1002/mc.22411] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2015] [Revised: 08/21/2015] [Accepted: 08/31/2015] [Indexed: 01/15/2023]
Abstract
Most tumors primarily rely on glycolysis rather than mitochondrial respiration for ATP production. This phenomenon, also known as Warburg effect, renders tumors more sensitive to glycolytic disturbances compared to normal cells. 3-bromopyruvate is a potent inhibitor of glycolysis that shows promise as an anticancer drug candidate. Although investigations revealed that 3-BP triggers apoptosis through ATP depletion and subsequent AMPK activation, the underlying molecular mechanisms coupling AMPK to apoptosis are poorly understood. We showed that 3-BP leads to a rapid ATP depletion which was followed by growth inhibition and Bax-dependent apoptosis in HCT116 cells. Apoptosis was accompanied with activation of caspase-9 and -3 while pretreatment with a general caspase inhibitor attenuated cell death. AMPK, p38, JNK, and Akt were phosphorylated immediately upon treatment. Pharmacological inhibition and silencing of AMPK largely inhibited 3-BP-induced apoptosis and reversed phosphorylation of JNK. Transcriptional activity of FoxO3a was dramatically increased subsequent to AMPK-mediated phosphorylation of FoxO3a at Ser413. Cell death analysis of cells transiently transfected with wt or AMPK-phosphorylation-deficient FoxO3 expression plasmids verified the contributory role of AMPK-FoxO3a axis in 3-BP-induced apoptosis. In addition, expression of proapoptotic Bcl-2 proteins Bim and Bax were upregulated in an AMPK-dependent manner. Bim was transcriptionally activated in association with FoxO3a activity, while Bax upregulation was abolished in p53-null cells. Together, these data suggest that AMPK couples 3-BP-induced metabolic disruption to intrinsic apoptosis via modulation of FoxO3a-Bim axis and Bax expression. © 2015 Wiley Periodicals, Inc.
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Affiliation(s)
- Cagri Bodur
- Molecular Biology, Genetics, and Bioengineering Program, Sabanci University, Tuzla, Istanbul, Turkey.
| | - Bahriye Karakas
- Molecular Biology, Genetics, and Bioengineering Program, Sabanci University, Tuzla, Istanbul, Turkey
| | - Ahmet Can Timucin
- Molecular Biology, Genetics, and Bioengineering Program, Sabanci University, Tuzla, Istanbul, Turkey
| | - Tugsan Tezil
- Molecular Biology, Genetics, and Bioengineering Program, Sabanci University, Tuzla, Istanbul, Turkey
| | - Huveyda Basaga
- Molecular Biology, Genetics, and Bioengineering Program, Sabanci University, Tuzla, Istanbul, Turkey
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8
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Kfir-Erenfeld S, Yefenof E. Non-genomic events determining the sensitivity of hemopoietic malignancies to glucocorticoid-induced apoptosis. Cancer Immunol Immunother 2014; 63:37-43. [PMID: 24072402 PMCID: PMC11028523 DOI: 10.1007/s00262-013-1477-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2013] [Accepted: 09/13/2013] [Indexed: 01/22/2023]
Abstract
Glucocorticoid (GC) hormones have been introduced as therapeutic agents in blood cancers six decades ago. The effectiveness of GC treatment stems from its ability to induce apoptotic death of hemopoietic cells. A major impediment in GC therapy is the acquisition of resistance to the drug upon repeated treatment. In addition, some blood cancers are a priori resistant to GC therapy. Usually, resistance to GC correlates with poor prognosis. Albeit the wide use of GC in clinical practice, their mode of action is not fully understood. The cellular response to GC is initiated by its binding to the cytosolic GC receptor (GR) that translocates to the nucleus and modulates gene expression. However, nuclear activities of GR occur in both apoptosis-sensitive and apoptosis-resistant cells. These apparent controversies can be resolved by deciphering non-genomic effects of GCs and the mode by which they modulate the apoptotic response. We suggest that non-genomic consequences of GC stimulation determine the cell fate toward survival or death. Understanding the cellular mechanisms of GC apoptotic sensitivity contributes to the development of new modalities for overcoming GC resistance.
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Affiliation(s)
- Shlomit Kfir-Erenfeld
- The Lautenberg Center for Immunology and Cancer Research, IMRIC, The Hebrew University-Hadassah Medical School, POB: 12272, 91120, Jerusalem, Israel,
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9
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Sharma A, Singh K, Mazumder S, Hill BT, Kalaycio M, Almasan A. BECN1 and BIM interactions with MCL-1 determine fludarabine resistance in leukemic B cells. Cell Death Dis 2013; 4:e628. [PMID: 23681223 PMCID: PMC3674362 DOI: 10.1038/cddis.2013.155] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2012] [Revised: 04/03/2013] [Accepted: 04/10/2013] [Indexed: 12/20/2022]
Abstract
The purine analog fludarabine (Fd) is an essential therapeutic for chronic lymphocytic leukemia (CLL). Innate or acquired resistance to Fd is a significant clinical problem and is largely mediated by increased expression of BCL-2 family members. The antiapoptotic BCL-2 family proteins inhibit both apoptosis and autophagy, therefore, downregulation of antiapoptotic BCL-2 family proteins and enhanced autophagy must coexist in cells dying in response to an apoptosis inducing therapeutic. However, in the drug-resistant cells that have an increased dependence on antiapoptotic proteins, whether autophagy is also inhibited remains unclear. Here, we examined the role of the BCL-2 family in regulating cell death and autophagy in leukemic cell lines and their derivative isogenic Fd-resistant (FdR) cells. MCL-1 degradation following Fd treatment freed the proapoptotic effectors BIM and BECN1, thus leading to cell death-associated autophagy in Fd-sensitive cells. However, in FdR cells, low BIM expression and BECN1 sequestration by MCL-1 prevented cell death. Consistently, in sensitive cells inhibition of apoptosis using siBIM and of both the early-phase autophagy nucleation steps by siBECN1, shATG7 or 3-methyladenine and the late-phase autophagy by shLAMP2, significantly reduced Fd-induced cell death. Paradoxically, FdR cells were addicted to basal autophagy, which was dependent on AMP-activated protein kinase (AMPK) but not BECN1. Moreover, in FdR cells, inhibition of autophagy by shLAMP2, but not siBECN1, enhanced cell death. The BH3-mimetic obatoclax released BIM and BECN1 from MCL-1 in Fd-sensitive and BECN1 from MCL-1 in FdR cells, and was effective at killing both Fd-sensitive and - resistant leukemic cells, including primary CLL cells. Therefore, a differential regulation of autophagy through BECN1 and AMPK signaling in Fd-sensitive and - resistant cells determines the different possible outcomes of autophagy inhibition. These findings suggest effective means to overcome Fd resistance by induction of BIM-dependent apoptosis and activation of BECN1-dependent autophagy.
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MESH Headings
- AMP-Activated Protein Kinases/metabolism
- Adenine/analogs & derivatives
- Adenine/pharmacology
- Antineoplastic Agents/pharmacology
- Antineoplastic Agents/therapeutic use
- Apoptosis/drug effects
- Apoptosis Regulatory Proteins/antagonists & inhibitors
- Apoptosis Regulatory Proteins/genetics
- Apoptosis Regulatory Proteins/metabolism
- Autophagy/drug effects
- Autophagy-Related Protein 7
- Bcl-2-Like Protein 11
- Beclin-1
- Cell Line, Tumor
- Drug Resistance, Neoplasm
- Humans
- Leukemia, Lymphocytic, Chronic, B-Cell/drug therapy
- Leukemia, Lymphocytic, Chronic, B-Cell/metabolism
- Leukemia, Lymphocytic, Chronic, B-Cell/pathology
- Lysosomal-Associated Membrane Protein 2/antagonists & inhibitors
- Lysosomal-Associated Membrane Protein 2/genetics
- Lysosomal-Associated Membrane Protein 2/metabolism
- Membrane Proteins/antagonists & inhibitors
- Membrane Proteins/genetics
- Membrane Proteins/metabolism
- Myeloid Cell Leukemia Sequence 1 Protein
- Protein Binding
- Proto-Oncogene Proteins/antagonists & inhibitors
- Proto-Oncogene Proteins/genetics
- Proto-Oncogene Proteins/metabolism
- Proto-Oncogene Proteins c-bcl-2/metabolism
- RNA Interference
- RNA, Small Interfering/metabolism
- Ubiquitin-Activating Enzymes/antagonists & inhibitors
- Ubiquitin-Activating Enzymes/genetics
- Ubiquitin-Activating Enzymes/metabolism
- Vidarabine/analogs & derivatives
- Vidarabine/pharmacology
- Vidarabine/therapeutic use
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Affiliation(s)
- A Sharma
- Department of Cancer Biology, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA
- Cleveland State University, Cleveland, OH, USA
| | - K Singh
- Department of Cancer Biology, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA
| | - S Mazumder
- Department of Cancer Biology, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA
| | - B T Hill
- Department of Hematologic Oncology and Blood Disorders, Taussig Cancer Institute, Cleveland Clinic, Cleveland, OH, USA
| | - M Kalaycio
- Department of Hematologic Oncology and Blood Disorders, Taussig Cancer Institute, Cleveland Clinic, Cleveland, OH, USA
| | - A Almasan
- Department of Cancer Biology, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA
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10
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Kashiwakura Y, Sakurai D, Kanno Y, Hashiguchi M, Kobayashi A, Kurosu A, Tokudome S, Kobata T, Kojima H. CD2-mediated regulation of peripheral CD4(+) CD25(+) regulatory T-cell apoptosis accompanied by down-regulation of Bim. Immunology 2013; 139:48-60. [PMID: 23278598 PMCID: PMC3634538 DOI: 10.1111/imm.12054] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2012] [Revised: 12/13/2012] [Accepted: 12/14/2012] [Indexed: 01/06/2023] Open
Abstract
Extensive studies on CD4(+) CD25(+) regulatory T (Treg) cells suggest that they are important in regulating immune responses. However, mechanisms of peripheral Treg cell homeostasis are unknown. We found that stromal cells isolated from secondary lymphoid organs such as spleen and lymph nodes could support the survival of Treg cells. This was dependent on CD2 engagement and a direct interaction between Treg cells and stromal cells. In the presence of stromal cells, Bim, a pro-apoptotic factor, was partially decreased in Treg cells. This effect could be inhibited by anti-CD2 blocking antibodies, indicating that stimulation through CD2 on Treg cells regulates Bim expression, which may be relevant to Treg cell apoptosis. Therefore, Treg cell interactions with stromal cells through CD2 may be essential for Treg cell survival. Surprisingly, the expression of CD2 ligands on stromal cells was not detected. Hence, it is not clear how CD2 on Treg cells contributes to a direct interaction with the stromal cells and participates in survival support for Treg cells. Taken together, CD2 stimuli were mandatory for Treg cell survival with reduced Bim expression, but CD2 may not function as a direct receptor for molecules on stromal cells.
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Affiliation(s)
- Yuji Kashiwakura
- Department of Immunology, Dokkyo Medical University School of Medicine, Mibu, Tochigi, Japan
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11
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Yu JH, Zhu BM, Riedlinger G, Kang K, Hennighausen L. The liver-specific tumor suppressor STAT5 controls expression of the reactive oxygen species-generating enzyme NOX4 and the proapoptotic proteins PUMA and BIM in mice. Hepatology 2012; 56:2375-86. [PMID: 22711600 PMCID: PMC3505809 DOI: 10.1002/hep.25900] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/05/2011] [Accepted: 06/01/2012] [Indexed: 01/08/2023]
Abstract
UNLABELLED Loss of signal transducer and activator of transcription 5 (STAT5) from liver tissue results in steatosis and enhanced cell proliferation. This study demonstrates that liver-specific Stat5-null mice develop severe hepatic steatosis as well as hepatocellular carcinomas at 17 months of age, even in the absence of chemical insults. To understand STAT5's role as a tumor suppressor, we identified and investigated new STAT5 target genes. Expression of Nox4, the gene encoding the reactive oxygen species (ROS)-generating enzyme NOX4, was induced by growth hormone through STAT5. In addition, the genes encoding the proapoptotic proteins PUMA and BIM were induced by growth hormone through STAT5, which bound to GAS motifs in the promoter regions of all three genes. We further show that STAT5-induced activation of Puma and Bim was dependent on NOX4. Treatment of mice with transforming growth factor-β, an inducer of apoptosis, resulted in cleaved caspase-3 in control but not in liver-specific Stat5-null mice. This study demonstrates for the first time that cytokines through STAT5 regulate the expression of the ROS-generating enzyme NOX4 and key proapoptotic proteins. CONCLUSION STAT5 harnesses several distinct signaling pathways in the liver and thereby functions as a tumor suppressor. Besides suppressing the activation of STAT3, STAT5 induces the expression of proapoptotic genes and the production of ROS.
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Affiliation(s)
- Ji Hoon Yu
- Laboratory of Genetics and Physiology, National Institute of Diabetes and Digestive and Kidney Diseases
| | - Bing-Mei Zhu
- Key Laboratory of Acupuncture and Medicine Research of Ministry of Education, Nanjing University of Chinese Medicine, Nanjing, China, 210029
| | - Gregory Riedlinger
- Laboratory of Pathology, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Keunsoo Kang
- Laboratory of Genetics and Physiology, National Institute of Diabetes and Digestive and Kidney Diseases
| | - Lothar Hennighausen
- Laboratory of Genetics and Physiology, National Institute of Diabetes and Digestive and Kidney Diseases,Department of Nanobiomedical Science and WCU Research Center of Nanobiomedical Science, Dankook University, Cheonan, Chungnam 330–714, Republic of Korea
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12
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Abstract
Increased interactions between pro-apoptotic BH3-only proteins and anti-apoptotic Bcl-2 family proteins at mitochondria result in tumor initiation, progression and resistance to traditional chemotherapy. Drugs that mimic the BH3 region are expected to release BH3-only proteins from anti-apoptotic proteins, inducing apoptosis in some cancer cells and sensitizing others to chemotherapy. Recently, we applied fluorescence lifetime imaging microscopy and fluorescence resonance energy transfer to measure protein:protein interactions for the Bcl-2 family of proteins in live MCF-7 cells using fluorescent fusion proteins. While the BH3-proteins bound to Bcl-XL and Bcl-2, the BH3 mimetic ABT-737 inhibited binding of only Bad and tBid, but not Bim. We have extended our studies by investigating ABT-263, a clinical drug based on ABT-737. We show that the inhibitory effects and pattern of the two drugs are comparable for both Bcl-XL and Bcl-2. Furthermore, we show that mutation of a conserved residue in the BH3 region in Bad and tBid disrupted their interactions with Bcl-XL and Bcl-2, while the corresponding BimEL mutant showed no decrease in binding to these anti-apoptotic proteins. Therefore, in MCF-7 cells, Bim has unique binding properties compared with other BH3-only proteins that resist displacement from Bcl-XL and Bcl-2 by BH3 mimetics.
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Affiliation(s)
- Qian Liu
- Department of Biochemistry and Biomedical Sciences; McMaster University; Hamilton, ON Canada
| | - Brian Leber
- Department of Biochemistry and Biomedical Sciences; McMaster University; Hamilton, ON Canada
- Department of Medicine; McMaster University; Hamilton, ON Canada
| | - David W. Andrews
- Department of Biochemistry and Biomedical Sciences; McMaster University; Hamilton, ON Canada
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13
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Klotz DM, Nelson SA, Kroboth K, Newton IP, Radulescu S, Ridgway RA, Sansom OJ, Appleton PL, Näthke IS. The microtubule poison vinorelbine kills cells independently of mitotic arrest and targets cells lacking the APC tumour suppressor more effectively. J Cell Sci 2012; 125:887-95. [PMID: 22399804 PMCID: PMC3311929 DOI: 10.1242/jcs.091843] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/28/2011] [Indexed: 12/26/2022] Open
Abstract
Colorectal cancers commonly carry truncation mutations in the adenomatous polyposis coli (APC) gene. The APC protein contributes to the stabilization of microtubules. Consistently, microtubules in cells lacking APC depolymerize more readily in response to microtubule-destabilizing drugs. This raises the possibility that such agents are suitable for treatment of APC-deficient cancers. However, APC-deficient cells have a compromised spindle assembly checkpoint, which renders them less sensitive to killing by microtubule poisons whose toxicity relies on the induction of prolonged mitotic arrest. Here, we describe the novel discovery that the clinically used microtubule-depolymerizing drug vinorelbine (Navelbine) kills APC-deficient cells in culture and in intestinal tissue more effectively than it kills wild-type cells. This is due to the ability of vinorelbine to kill cells in interphase independently of mitotic arrest. Consistent with a role for p53 in cell death in interphase, depletion of p53 renders cells less sensitive to vinorelbine, but only in the presence of wild-type APC. The pro-apoptotic protein BIM (also known as BCL2L11) is recruited to mitochondria in response to vinorelbine, where it can inhibit the anti-apoptotic protein BCL2, suggesting that BIM mediates vinorelbine-induced cell death. This recruitment of BIM is enhanced in cells lacking APC. Consistently, BIM depletion dampens the selective effect of vinorelbine on these cells. Our findings reveal that vinorelbine is a potential therapeutic agent for colorectal cancer, but they also illustrate the importance of the APC tumour suppressor status when predicting therapeutic efficacy.
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Affiliation(s)
- Daniel M. Klotz
- Division of Cell and Developmental Biology, University of Dundee, Dow Street, Dundee, DD1 5EH, UK
| | - Scott A. Nelson
- Division of Cell and Developmental Biology, University of Dundee, Dow Street, Dundee, DD1 5EH, UK
| | - Karin Kroboth
- Division of Molecular Medicine, University of Dundee, Dow Street, Dundee, DD1 5EH, UK
| | - Ian P. Newton
- Division of Cell and Developmental Biology, University of Dundee, Dow Street, Dundee, DD1 5EH, UK
| | - Sorina Radulescu
- The Beatson Institute for Cancer Research, Garscube Estate, Switchback Road, Bearsden, Glasgow, G61 1BD, UK
| | - Rachel A. Ridgway
- The Beatson Institute for Cancer Research, Garscube Estate, Switchback Road, Bearsden, Glasgow, G61 1BD, UK
| | - Owen J. Sansom
- The Beatson Institute for Cancer Research, Garscube Estate, Switchback Road, Bearsden, Glasgow, G61 1BD, UK
| | - Paul L. Appleton
- Division of Cell and Developmental Biology, University of Dundee, Dow Street, Dundee, DD1 5EH, UK
| | - Inke S. Näthke
- Division of Cell and Developmental Biology, University of Dundee, Dow Street, Dundee, DD1 5EH, UK
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14
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Cowburn AS, Summers C, Dunmore BJ, Farahi N, Hayhoe RP, Print CG, Cook SJ, Chilvers ER. Granulocyte/macrophage colony-stimulating factor causes a paradoxical increase in the BH3-only pro-apoptotic protein Bim in human neutrophils. Am J Respir Cell Mol Biol 2011; 44:879-87. [PMID: 20705940 PMCID: PMC4373550 DOI: 10.1165/rcmb.2010-0101oc] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Neutrophil apoptosis is essential for the resolution of inflammation but is delayed by several inflammatory mediators. In such terminally differentiated cells it has been uncertain whether these agents can inhibit apoptosis through transcriptional regulation of anti-death (Bcl-X(L), Mcl-1, Bcl2A1) or BH3-only (Bim, Bid, Puma) Bcl2-family proteins. We report that granulocyte/macrophage colony-stimulating factor (GM-CSF) and tumor necrosis factor (TNF)-α prevent the normal time-dependent loss of Mcl-1 and Bcl2A1 in neutrophils, and we demonstrate that they cause an NF-κB-dependent increase in Bcl-X(L) transcription/translation. We show that GM-CSF and TNF-α increase and/or maintain mRNA levels for the pro-apoptotic BH3-only protein Bid and that GM-CSF has a similar NF-κB-dependent effect on Bim transcription and BimEL expression. The in-vivo relevance of these findings was indicated by demonstrating that GM-CSF is the dominant neutrophil survival factor in lung lavage from patients with ventilator-associated pneumonia, confirming an increase in lung neutrophil Bim mRNA. Finally GM-CSF caused mitochondrial location of Bim and a switch in phenotype to a cell that displays accelerated caspase-9-dependent apoptosis. This study demonstrates the capacity of neutrophil survival agents to induce a paradoxical increase in the pro-apoptotic proteins Bid and Bim and suggests that this may function to facilitate rapid apoptosis at the termination of the inflammatory cycle.
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Affiliation(s)
- Andrew S Cowburn
- Department of Medicine, University of Cambridge School of Clinical Medicine, Cambridge, United Kingdom.
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15
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Li D, Qu Y, Mao M, Zhang X, Li J, Ferriero D, Mu D. Involvement of the PTEN-AKT-FOXO3a pathway in neuronal apoptosis in developing rat brain after hypoxia-ischemia. J Cereb Blood Flow Metab 2009; 29:1903-13. [PMID: 19623194 DOI: 10.1038/jcbfm.2009.102] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The proapoptotic function of phosphatase and tensin homolog deleted on chromosome 10 (PTEN) phosphatase has been linked to its capacity to antagonize the phosphatidylinositol-3-kinase-Akt signaling pathway. Previous studies have shown that the Forkhead transcriptional factor (FOXO3a) is a critical effector of the PTEN-mediated tumor suppressor. However, whether the PTEN-Akt-FOXO3a pathway is involved in neuronal apoptosis in developing rat brain after hypoxia-ischemia (HI) is unclear. In this study, we generated an HI model using postnatal day 10 rats. Immunohistochemistry and western blot were used to detect the expression of total and phosphorylated PTEN, Akt, and FOXO3a, as well as its target gene Bim. We found that dephosphorylation of PTEN was accompanied by dephosphorylation of Akt and FOXO3a, which induced FOXO3a translocation into the nucleus and upregulated the expression of Bim. Furthermore, we found that PTEN inhibition by bisperoxovanadium significantly increased the phosphorylation of Akt and FOXO3a, decreased the nuclear translocation of FOXO3a, and inhibited Bim expression after HI. Moreover, the downregulation of Bim caused by PTEN inhibition attenuated cellular apoptosis in developing rat brain. Our findings suggest that the PTEN-Akt-FOXO3a pathway is involved in neuronal apoptosis in neonatal rat brain after HI. Agents targeting PTEN may offer a promise to rescue neurons from HI brain damage.
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16
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Abstract
UNLABELLED Activation of c-Jun N-terminal kinase (JNK) has been implicated as a mechanism in the development of steatohepatitis. This finding, together with the reported role of JNK signaling in the development of obesity and insulin resistance, two components of the metabolic syndrome and predisposing factors for fatty liver disease, suggests that JNK may be a central mediator of the metabolic syndrome and an important therapeutic target in steatohepatitis. To define the isoform-specific functions of JNK in steatohepatitis associated with obesity and insulin resistance, the effects of JNK1 or JNK2 ablation were determined in developing and established steatohepatitis induced by a high-fat diet (HFD). HFD-fed jnk1 null mice failed to develop excessive weight gain, insulin resistance, or steatohepatitis. In contrast, jnk2(-/-) mice fed a HFD were obese and insulin-resistant, similar to wild-type mice, and had increased liver injury. In mice with established steatohepatitis, an antisense oligonucleotide knockdown of jnk1 decreased the amount of steatohepatitis in concert with a normalization of insulin sensitivity. Knockdown of jnk2 improved insulin sensitivity but had no effect on hepatic steatosis and markedly increased liver injury. A jnk2 knockdown increased hepatic expression of the proapoptotic Bcl-2 family members Bim and Bax and the increase in liver injury resulted in part from a Bim-dependent activation of the mitochondrial death pathway. CONCLUSION JNK1 and JNK2 both mediate insulin resistance in HFD-fed mice, but the JNK isoforms have distinct effects on steatohepatitis, with JNK1 promoting steatosis and hepatitis and JNK2 inhibiting hepatocyte cell death by blocking the mitochondrial death pathway.
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Affiliation(s)
- Rajat Singh
- Department of Medicine, Albert Einstein College of Medicine Bronx, NY, 10461,Marion Bessin Liver Research Center, Albert Einstein College of Medicine Bronx, NY, 10461
| | - Yongjun Wang
- Department of Medicine, Albert Einstein College of Medicine Bronx, NY, 10461,Marion Bessin Liver Research Center, Albert Einstein College of Medicine Bronx, NY, 10461
| | - Youqing Xiang
- Department of Medicine, Albert Einstein College of Medicine Bronx, NY, 10461,Marion Bessin Liver Research Center, Albert Einstein College of Medicine Bronx, NY, 10461
| | - Kathryn E. Tanaka
- Department of Pathology, Albert Einstein College of Medicine Bronx, NY, 10461
| | | | - Mark J. Czaja
- Department of Medicine, Albert Einstein College of Medicine Bronx, NY, 10461,Marion Bessin Liver Research Center, Albert Einstein College of Medicine Bronx, NY, 10461
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17
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Abstract
Nonalcoholic fatty liver disease (NAFLD) is characterized by insulin resistance, which results in elevated serum concentration of free fatty acids (FFAs). Circulating FFAs provide the substrate for triacylglycerol formation in the liver, and may also be directly cytotoxic. Hepatocyte apoptosis is a key histologic feature of NAFLD, and correlates with progressive inflammation and fibrosis. The molecular pathways leading to hepatocyte apoptosis are not fully defined; however, recent studies suggest that FFA-induced apoptosis contributes to the pathogenesis of nonalcoholic steatohepatitis. FFAs directly engage the core apoptotic machinery by activating the proapoptotic protein Bax, in a c-jun N-terminal kinase-dependent manner. FFAs also activate the lysosomal pathway of cell death and regulate death receptor gene expression. The role of ER stress and oxidative stress in the pathogenesis of nonalcoholic steatohepatitis has also been described. Understanding the molecular mediators of liver injury should promote development of mechanism-based therapeutic interventions.
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Affiliation(s)
- Harmeet Malhi
- Miles and Shirley Fiterman Center for Digestive Diseases, Mayo Clinic, College of Medicine, Rochester, Minnesota
| | - Gregory J. Gores
- Miles and Shirley Fiterman Center for Digestive Diseases, Mayo Clinic, College of Medicine, Rochester, Minnesota
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18
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Abstract
INTRODUCTION Osteoblasts depend on a constant supply of prosurvival signals from their microenvironment. When trophic factors become limited by injury or disease, cells undergo apoptosis. This study establishes the regulation and function of Bim, Bak, and Bax in this response. MATERIALS AND METHODS MBA-15.4 murine osteoblasts and primary human bone marrow stromal cells (hBMSCs) were subjected to growth factor depletion by serum starvation (1% FCS or serum withdrawal). Protein phosphorylation, activation, or expression was quantified by Western blotting and gene expression by real-time PCR. Regulation of apoptosis in response to serum depletion was determined using siRNA specific for Bim, Bak, or Bax, followed by TUNEL staining. Statistical significance was determined by one-way ANOVA after multiple experimental repeats. RESULTS Serum depletion strongly induced expression of the proapoptotic protein Bim in both hBMSC and MBA-15.4 osteoblasts. Detailed analysis of the mouse line showed that both mRNA and protein levels rose from 2 h to peak between 16 and 24 h, in conjunction with activation of caspase 3 and rising levels of apoptosis. Both actinomycin D and cycloheximide prevented this increase in Bim, indicating transcriptional regulation. Serum deprivation caused immediate and sustained decreases in phosphorylation of prosurvival kinases, ERK and PKB, preceding upregulation of Bim. Pathway inhibitors, U0126 or LY294002, strongly increased both Bim mRNA and protein, confirming that both kinases regulate Bim. These inhibitors also induced osteoblast apoptosis within 24-72 h. JC-1 tracer detected mitochondrial potential disruption after serum deprivation, indicating involvement of the intrinsic pathway. Moreover, activation-associated conformational changes were detected in the channel-formers, Bax and Bak. Selective knockdown of Bim or Bak by siRNA protected osteoblasts from serum depletion-induced apoptosis by 50%, whereas knockdown of Bax alone or Bak and Bax together reduced apoptosis by 90%. CONCLUSIONS Our data indicate that Bim, Bak, and Bax actively mediate osteoblast apoptosis induced by trophic factor withdrawal. The complex upstream regulation of Bim may provide targets for therapeutic enhancement of osteoblast viability.
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19
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Lindemann RK, Newbold A, Whitecross KF, Cluse LA, Frew AJ, Ellis L, Williams S, Wiegmans AP, Dear AE, Scott CL, Pellegrini M, Wei A, Richon VM, Marks PA, Lowe SW, Smyth MJ, Johnstone RW. Analysis of the apoptotic and therapeutic activities of histone deacetylase inhibitors by using a mouse model of B cell lymphoma. Proc Natl Acad Sci U S A 2007; 104:8071-6. [PMID: 17470784 PMCID: PMC1876573 DOI: 10.1073/pnas.0702294104] [Citation(s) in RCA: 176] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2007] [Indexed: 11/18/2022] Open
Abstract
Histone deacetylase inhibitors (HDACi) can elicit a range of biological responses that affect tumor growth and survival, including inhibition of cell cycle progression, induction of tumor cell-selective apoptosis, suppression of angiogenesis, and modulation of immune responses, and show promising activity against hematological malignancies in clinical trials. Using the Emu-myc model of B cell lymphoma, we screened tumors with defined genetic alterations in apoptotic pathways for therapeutic responsiveness to the HDACi vorinostat. We demonstrated a direct correlation between induction of tumor cell apoptosis in vivo and therapeutic efficacy. Vorinostat did not require p53 activity or a functional death receptor pathway to kill Emu-myc lymphomas and mediate a therapeutic response but depended on activation of the intrinsic apoptotic pathway with the proapoptotic BH3-only proteins Bid and Bim playing an important role. Our studies provide important information regarding the mechanisms of action of HDACi that have broad implications regarding stratification of patients receiving HDACi therapy alone or in combination with other anticancer agents.
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Affiliation(s)
- R. K. Lindemann
- *Cancer Immunology Program, The Peter MacCallum Cancer Institute, Trescowthick Research Laboratories, St. Andrews Place, East Melbourne, Victoria 3002, Australia
| | - A. Newbold
- *Cancer Immunology Program, The Peter MacCallum Cancer Institute, Trescowthick Research Laboratories, St. Andrews Place, East Melbourne, Victoria 3002, Australia
| | - K. F. Whitecross
- *Cancer Immunology Program, The Peter MacCallum Cancer Institute, Trescowthick Research Laboratories, St. Andrews Place, East Melbourne, Victoria 3002, Australia
| | - L. A. Cluse
- *Cancer Immunology Program, The Peter MacCallum Cancer Institute, Trescowthick Research Laboratories, St. Andrews Place, East Melbourne, Victoria 3002, Australia
| | - A. J. Frew
- *Cancer Immunology Program, The Peter MacCallum Cancer Institute, Trescowthick Research Laboratories, St. Andrews Place, East Melbourne, Victoria 3002, Australia
| | - L. Ellis
- *Cancer Immunology Program, The Peter MacCallum Cancer Institute, Trescowthick Research Laboratories, St. Andrews Place, East Melbourne, Victoria 3002, Australia
| | - S. Williams
- *Cancer Immunology Program, The Peter MacCallum Cancer Institute, Trescowthick Research Laboratories, St. Andrews Place, East Melbourne, Victoria 3002, Australia
| | - A. P. Wiegmans
- *Cancer Immunology Program, The Peter MacCallum Cancer Institute, Trescowthick Research Laboratories, St. Andrews Place, East Melbourne, Victoria 3002, Australia
| | - A. E. Dear
- Australian Centre for Blood Diseases, Monash University, 6th Floor, Burnet Building, Prahran, Melbourne, Victoria 3181, Australia
| | - C. L. Scott
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724
- The Walter and Eliza Hall Institute, Melbourne, Victoria 3050, Australia
| | - M. Pellegrini
- The Walter and Eliza Hall Institute, Melbourne, Victoria 3050, Australia
| | - A. Wei
- The Walter and Eliza Hall Institute, Melbourne, Victoria 3050, Australia
| | - V. M. Richon
- Merck & Co., 33 Avenue Louis Pasteur, Boston, MA 02115; and
| | - Paul A. Marks
- Memorial Sloan–Kettering Cancer Center, New York, NY 10021
| | - S. W. Lowe
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724
| | - M. J. Smyth
- *Cancer Immunology Program, The Peter MacCallum Cancer Institute, Trescowthick Research Laboratories, St. Andrews Place, East Melbourne, Victoria 3002, Australia
- Department of Pathology, University of Melbourne, Parkville, Victoria 3054, Australia
| | - R. W. Johnstone
- *Cancer Immunology Program, The Peter MacCallum Cancer Institute, Trescowthick Research Laboratories, St. Andrews Place, East Melbourne, Victoria 3002, Australia
- Department of Pathology, University of Melbourne, Parkville, Victoria 3054, Australia
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20
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Yang JY, Xia W, Hu MCT. Ionizing radiation activates expression of FOXO3a, Fas ligand, and Bim, and induces cell apoptosis. Int J Oncol 2006; 29:643-8. [PMID: 16865280 PMCID: PMC2632978] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/11/2023] Open
Abstract
Genotoxic stress such as ionizing radiation can induce DNA damage and promote cell-cycle arrest or apoptosis through either a p53-dependent or -independent pathway. Recently, members of the FOXO Forkhead transcription factor family have been implicated in playing a role in both DNA repair and apoptosis in mammalian cells that promoted us to examine the role of FOXO transcription factors in ionizing radiation-induced apoptosis. Here, we show that ionizing radiation can promote FOXO3a (FKHRL1) transcriptional activity and protein expression level, and induce nuclear translocation of FOXO3a in Saos2, a p53-null osteosarcoma cell line. Ionizing radiation stimulates expression of apoptosis-inducing proteins such as Fas ligand and the Bcl-2 interacting mediator of cell death (Bim) leading to cellular apoptosis. The observed upregulation of proapoptotic genes and apoptosis in cells without p53 in response to ionizing radiation suggests a novel p53-independent mechanism underlying ionizing radiation-induced apoptosis in cancer cells.
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Affiliation(s)
- Jer-Yen Yang
- Department of Molecular and Cellular Oncology, The University of Texas M.D. Anderson Cancer Center, Houston, 77030, USA
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21
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Linseman DA, Phelps RA, Bouchard RJ, Le SS, Laessig TA, McClure ML, Heidenreich KA. Insulin-like growth factor-I blocks Bcl-2 interacting mediator of cell death ( Bim) induction and intrinsic death signaling in cerebellar granule neurons. J Neurosci 2002; 22:9287-97. [PMID: 12417654 PMCID: PMC6758065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/27/2023] Open
Abstract
Cerebellar granule neurons depend on insulin-like growth factor-I (IGF-I) for their survival. However, the mechanism underlying the neuroprotective effects of IGF-I is presently unclear. Here we show that IGF-I protects granule neurons by suppressing key elements of the intrinsic (mitochondrial) death pathway. IGF-I blocked activation of the executioner caspase-3 and the intrinsic initiator caspase-9 in primary cerebellar granule neurons deprived of serum and depolarizing potassium. IGF-I inhibited cytochrome c release from mitochondria and prevented its redistribution to neuronal processes. The effects of IGF-I on cytochrome c release were not mediated by blockade of the mitochondrial permeability transition pore, because IGF-I failed to inhibit mitochondrial swelling or depolarization. In contrast, IGF-I blocked induction of the BH3-only Bcl-2 family member, Bim (Bcl-2 interacting mediator of cell death), a mediator of Bax-dependent cytochrome c release. The suppression of Bim expression by IGF-I did not involve inhibition of the c-Jun transcription factor. Instead, IGF-I prevented activation of the forkhead family member, FKHRL1, another transcriptional regulator of Bim. Finally, adenoviral-mediated expression of dominant-negative AKT activated FKHRL1 and induced expression of Bim. These data suggest that IGF-I signaling via AKT promotes survival of cerebellar granule neurons by blocking the FKHRL1-dependent transcription of Bim, a principal effector of the intrinsic death-signaling cascade.
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Affiliation(s)
- Daniel A Linseman
- Department of Pharmacology, University of Colorado Health Sciences Center and the Denver Veterans Affairs Medical Center, Denver, Colorado 80262, USA
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22
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Zong WX, Lindsten T, Ross AJ, MacGregor GR, Thompson CB. BH3-only proteins that bind pro-survival Bcl-2 family members fail to induce apoptosis in the absence of Bax and Bak. Genes Dev 2001; 15:1481-6. [PMID: 11410528 PMCID: PMC312722 DOI: 10.1101/gad.897601] [Citation(s) in RCA: 624] [Impact Index Per Article: 27.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The BH3-only proteins Bim and Bad bind to the antiapoptotic Bcl-2 proteins and induce apoptosis in wild-type cells and cells from either bax(-/-) or bak(-/-) animals. In contrast, constitutively active forms of Bim and Bad failed to induce apoptosis in bax(-/-)bak(-/-) cells. Expression of Bax restored susceptibility of the cells to Bim and Bad. In addition, Bax but not Bim or Bad sensitized the bax(-/-)bak(-/-) cells to a wide variety of cell death stimuli including UV irradiation, chemotherapeutic agents, and ER stress. These results suggest that neither activation of BH3-only proteins nor suppression of pro-survival Bcl-2 proteins is sufficient to kill cells in the absence of both Bax and Bak. Furthermore, whereas mouse embryo fibroblasts (MEF) expressing only Bax or Bak displayed resistance to transformation, bax(-/-)bak(-/-) MEF were nearly as prone to oncogenic transformation as p53(-/-) MEF. Thus, the function of either Bax or Bak appears required to initiate most forms of apoptosis and to suppress oncogenic transformation.
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Affiliation(s)
- W X Zong
- Department of Medicine, Abramson Family Cancer Research Institute, University of Pennsylvania, Philadelphia, PA 19104, USA
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