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High ROS Production by Celecoxib and Enhanced Sensitivity for Death Ligand-Induced Apoptosis in Cutaneous SCC Cell Lines. Int J Mol Sci 2021; 22:ijms22073622. [PMID: 33807213 PMCID: PMC8036359 DOI: 10.3390/ijms22073622] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Revised: 03/24/2021] [Accepted: 03/26/2021] [Indexed: 12/11/2022] Open
Abstract
Incidence of cutaneous squamous cell carcinoma (cSCC) and actinic keratosis has increased worldwide, and non-steroidal anti-inflammatory drugs as celecoxib are considered for treatment. We show here strong anti-proliferative effects of celecoxib in four cSCC cell lines, while apoptosis and cell viability largely remained unaffected. Impeded apoptosis was overcome in combinations with agonistic CD95 antibody or TNF-related apoptosis-inducing ligand (TRAIL), resulting in up to 60% apoptosis and almost complete loss of cell viability. Proapoptotic caspase cascades were activated, and apoptosis was suppressed by caspase inhibition. TRAIL receptor (DR5) and proapoptotic Bcl-2 proteins (Puma and Bad) were upregulated, while anti-apoptotic factors (survivin, XIAP, cFLIP, Mcl-1, and Bcl-w) were downregulated. Strongly elevated levels of reactive oxygen species (ROS) turned out as particularly characteristic for celecoxib, appearing already after 2 h. ROS production alone was not sufficient for apoptosis induction but may play a critical role in sensitizing cancer cells for apoptosis and therapy. Thus, the full therapeutic potential of celecoxib may be better used in combinations with death ligands. Furthermore, the immune response against cSCC/AK may be improved by celecoxib, and combinations with checkpoint inhibitors, recently approved for the treatment of cSCC, may be considered.
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2
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Quinolizidine alkaloids derivatives from Sophora alopecuroides Linn: Bioactivities, structure-activity relationships and preliminary molecular mechanisms. Eur J Med Chem 2019; 188:111972. [PMID: 31884408 DOI: 10.1016/j.ejmech.2019.111972] [Citation(s) in RCA: 62] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Revised: 11/24/2019] [Accepted: 12/12/2019] [Indexed: 02/05/2023]
Abstract
Quinolizidine alkaloids, as essential active ingredients extracted from Sophora alopecuroides Linn, have been well concerned in the past several decades owing to the unique structural features and numerous pharmacological activities. Quinolizidine alkaloids consist of matrine, oxymatrine, sophoridine, sophocarpine and aloperine etc. Additionally, quinolizidine alkaloids exert various excellent activities, including anti-cancer, anti-inflammation, anti-fibrosis, anti-virus and anti-arrhythmia regulations. In this review, we comprehensively clarify the pharmacological activities of quinolizidine alkaloids, as well as the relationship between biological function and structure-activity of substituted quinolizidine alkaloids. We believe that biological agents based on the pharmacological functions of quinolizidine alkaloids could be well applied in clinical practice.
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3
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Shi P, Zhang S, Zhu L, Qian G, Ren H, Ramalingam SS, Chen M, Sun SY. The Third-Generation EGFR Inhibitor, Osimertinib, Promotes c-FLIP Degradation, Enhancing Apoptosis Including TRAIL-Induced Apoptosis in NSCLC Cells with Activating EGFR Mutations. Transl Oncol 2019; 12:705-713. [PMID: 30856555 PMCID: PMC6411612 DOI: 10.1016/j.tranon.2019.02.006] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Revised: 02/11/2019] [Accepted: 02/14/2019] [Indexed: 01/25/2023] Open
Abstract
The third-generation EGFR inhibitor, osimertinib (AZD9291), selectively and irreversibly inhibits EGFR activating and T790 M mutants while sparing wild-type EGFR. Osimertinib is now an approved drug for non-small cell lung cancer (NSCLC) patients with activating EGFR mutations (first-line) or those who have become resistant to 1st generation EGFR inhibitors through the T790 M mutation (second-line). Unfortunately, all patients eventually relapse and develop resistance to osimertinib. Hence, it is essential to fully understand the biology underlying the development of resistance to osimertinib in order to improve its therapeutic efficacy and overcome resistance. Cellular FLICE-inhibitory protein (c-FLIP) is a truncated form of caspase-8 and functions as a key inhibitor of the extrinsic apoptotic pathway. The current study has demonstrated that osimertinib reduces c-FLIP levels via facilitating its degradation and enhances apoptosis induced by tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) primarily in NSCLC with activating EGFR mutations. Moreover, modulation of c-FLIP expression levels, to some degree, also alters the sensitivities of EGFR mutant NSCLC cells to undergo osimertinib-induced apoptosis, suggesting that c-FLIP suppression is an important event contributing to the antitumor activity of osimertinib against EGFR mutant NSCLC.
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Affiliation(s)
- Puyu Shi
- First Affiliated Hospital of Medical College of Xi'an Jiaotong University, Xi'an, Shaanxi, PR China; Department of Hematology and Medical Oncology, Emory University School of Medicine and Winship Cancer Institute, Atlanta, GA, USA
| | - Shuo Zhang
- First Affiliated Hospital of Medical College of Xi'an Jiaotong University, Xi'an, Shaanxi, PR China; Department of Hematology and Medical Oncology, Emory University School of Medicine and Winship Cancer Institute, Atlanta, GA, USA
| | - Lei Zhu
- Department of Hematology and Medical Oncology, Emory University School of Medicine and Winship Cancer Institute, Atlanta, GA, USA; Anhui Provincial Engineering Research Center for Polysaccharide Drug, Anhui Province Key Laboratory of Active Biological Macro-molecules, School of Pharmacy, Wannan Medical College, Wuhu, Anhui, PR China
| | - Guoqing Qian
- Department of Hematology and Medical Oncology, Emory University School of Medicine and Winship Cancer Institute, Atlanta, GA, USA
| | - Hui Ren
- First Affiliated Hospital of Medical College of Xi'an Jiaotong University, Xi'an, Shaanxi, PR China
| | - Suresh S Ramalingam
- Department of Hematology and Medical Oncology, Emory University School of Medicine and Winship Cancer Institute, Atlanta, GA, USA
| | - Mingwei Chen
- First Affiliated Hospital of Medical College of Xi'an Jiaotong University, Xi'an, Shaanxi, PR China
| | - Shi-Yong Sun
- Department of Hematology and Medical Oncology, Emory University School of Medicine and Winship Cancer Institute, Atlanta, GA, USA.
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4
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Rescifina A, Surdo E, Cardile V, Avola R, Eleonora Graziano AC, Stancanelli R, Tommasini S, Pistarà V, Ventura CA. Gemcitabine anticancer activity enhancement by water soluble celecoxib/sulfobutyl ether-β-cyclodextrin inclusion complex. Carbohydr Polym 2018; 206:792-800. [PMID: 30553385 DOI: 10.1016/j.carbpol.2018.11.060] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2018] [Revised: 11/18/2018] [Accepted: 11/18/2018] [Indexed: 12/12/2022]
Abstract
We investigated the complexation of celecoxib (CCB) into sulfobuthyl-ether-β-cyclodextrin (SBE-β-CD) for the realization of an inhalable dry-powder formulation containing gemcitabine (GEM) for lung anticancer therapy. Complexation increased the water solubility of CCB (0.003 mg/mL and 0.834 mg/mL for CCB free and complexed, respectively) and produced a quantitative dissolution of the drug within 15 min. The CCB/SBE-β-CD inclusion complex showed a high stability constant (8131 M-1) not influenced by the presence of GEM in solution. Two-dimensional NMR experiments and computational studies demonstrated that the pyrazole ring of CCB penetrates deeper into SBE-β-CD from the secondary rim. The aromatic rings are positioned at the edge of the cavity, establishing hydrogen bonds with the SBE-β-CD that stabilized the complex. CCB showed limited cytotoxic activity on A549 cell lines. Complexation significantly increased activity passing from 30% to 45% cell mortality. Moreover, CCB/SBE-β-CD strongly improved the cytotoxicity of GEM, observing about 60% of cell mortality for the combined formulation.
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Affiliation(s)
- Antonio Rescifina
- Department of Drug Sciences, University of Catania, V.le A. Doria, 6 - 95125 Catania, Italy.
| | - Emanuela Surdo
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, V.le F. Stagno D'Alcontrés, 31 - 98166 Messina, Italy.
| | - Venera Cardile
- Department of Biomedical and Biotechnological Sciences, University of Catania, Via Santa Sofia, 97 - 95125 Catania, Italy.
| | - Rosanna Avola
- Department of Biomedical and Biotechnological Sciences, University of Catania, Via Santa Sofia, 97 - 95125 Catania, Italy.
| | | | - Rosanna Stancanelli
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, V.le F. Stagno D'Alcontrés, 31 - 98166 Messina, Italy.
| | - Silvana Tommasini
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, V.le F. Stagno D'Alcontrés, 31 - 98166 Messina, Italy.
| | - Venerando Pistarà
- Department of Drug Sciences, University of Catania, V.le A. Doria, 6 - 95125 Catania, Italy.
| | - Cinzia Anna Ventura
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, V.le F. Stagno D'Alcontrés, 31 - 98166 Messina, Italy.
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5
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Ge Y, Gao Q, Yan F, Zhang X, Liu Y, Zhou Y. Su Yang Decoction induces human colon carcinoma cell apoptosis by activating caspases. Oncol Lett 2018; 17:422-431. [PMID: 30655783 DOI: 10.3892/ol.2018.9625] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2017] [Accepted: 07/05/2018] [Indexed: 01/03/2023] Open
Abstract
Su Yang Decoction (SYD) is a popular healthcare product comprised of various brassicaceous vegetables known to exhibit anticancer activity. However, the effects of SYD on tumor growth, following its combination with brassicaceous vegetables into a compound formula, require further investigation. In the present study, a quality control of SYD was subjected to high-performance liquid chromatography for the quantitative and qualitative determination of sulforaphane, the main anticancer component of SYD. SYD inhibited colon cancer cell proliferation in a dose- and time-dependent manner and induced G1 phase arrest in colon cancer HT-29 cell lines. In addition, SYD triggered caspase-mediated apoptosis in a dose-dependent manner and induced the cleavage of poly (ADP-ribose) polymerase, tumor necrosis factor superfamily member 10, X-linked inhibitor of apoptosis, and truncated BH3 interacting domain death agonist. Furthermore, the expression of FADD-like interleukin-1β-converting enzyme (FLICE)-like inhibitory proteins (FLIPs) and long isoform of FLICE-inhibitory protein was reduced by SYD and the direct targeting of cellular-FLIP with small interfering RNA inhibited colon cancer cell proliferation and decreased the SYD concentration required for proliferation inhibition. SYD treatment was also associated with the translocation of proapoptotic BCL2 associated X, apoptosis regulator to the mitochondria and the release of cytochrome c from the mitochondria to the cytosol. The aforementioned results indicate that SYD exerts anti-colorectal cancer effects through an underlying mechanism that may involve caspase activation.
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Affiliation(s)
- Yazhong Ge
- Department of Healthy Food Development, Infinitus (China) Company Ltd., Guangzhou, Guangdong 510024, P.R. China.,School of Food Science and Engineering, South China University of Technology, Guangzhou, Guangdong 510102, P.R. China.,Department of Pharmacology, College of Pharmaceutical Science, Guangzhou Medical University, Guangzhou, Guangdong 511436, P.R. China
| | - Qing Gao
- Department of Healthy Food Development, Infinitus (China) Company Ltd., Guangzhou, Guangdong 510024, P.R. China.,Department of Pharmacology, College of Pharmaceutical Science, Guangzhou Medical University, Guangzhou, Guangdong 511436, P.R. China
| | - Fengjiao Yan
- Department of Pharmacology, College of Pharmaceutical Science, Guangzhou Medical University, Guangzhou, Guangdong 511436, P.R. China.,Department of Cardiovascular Medicine, The First Affiliated Hospital of Sun-Yat-sen University, Guangzhou, Guangdong 510080, P.R. China
| | - Xiaona Zhang
- Department of Pharmacology, College of Pharmaceutical Science, Guangzhou Medical University, Guangzhou, Guangdong 511436, P.R. China.,Department of Pharmacology, The Sixth Affiliated Hospital of Sun-Yat-sen University, Guangzhou, Guangdong 510520, P.R. China
| | - Yurong Liu
- Department of Pharmacology, College of Pharmaceutical Science, Guangzhou Medical University, Guangzhou, Guangdong 511436, P.R. China
| | - Yi Zhou
- Department of Pharmacology, College of Pharmaceutical Science, Guangzhou Medical University, Guangzhou, Guangdong 511436, P.R. China
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6
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Kleinesudeik L, Rohde K, Fulda S. Regulation of the antiapoptotic protein cFLIP by the glucocorticoid Dexamethasone in ALL cells. Oncotarget 2018; 9:16521-16532. [PMID: 29662664 PMCID: PMC5893259 DOI: 10.18632/oncotarget.24782] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2017] [Accepted: 02/26/2018] [Indexed: 01/04/2023] Open
Abstract
We recently reported that the Smac mimetic BV6 and glucocorticoids, e.g. Dexamethasone (Dexa), synergize to induce cell death in acute lymphoblastic leukemia (ALL) in vitro and in vivo. Here, we discover that this synergism involves Dexa-stimulated downregulation of cellular FLICE-like inhibitory protein (cFLIP) in ALL cells. Dexa rapidly decreases cFLIPL protein levels, which is further enhanced by addition of BV6. While attenuating the activation of non-canonical nuclear factor-kappaB (NF-κB) signaling by BV6, Dexa suppresses cFLIPL protein but not mRNA levels pointing to a transcription-independent downregulation of cFLIPL by Dexa. Analysis of protein degradation pathways indicates that Dexa causes cFLIPL depletion independently of proteasomal, lysosomal or caspase pathways, as inhibitors of the proteasome, lysosomal enzymes or caspases all failed to protect from Dexa-mediated loss of cFLIPL protein. Also, Dexa alone or in combination with BV6 does not affect overall activity of the proteasome. Importantly, overexpression of cFLIPL to an extent that is no longer subject to Dexa-imposed downregulation rescues Dexa/BV6-mediated cell death. Vice versa, knockdown of cFLIP increases BV6-mediated cell death, thus mimicking the effect of Dexa. Altogether, these data demonstrate that Dexa-mediated downregulation of cFLIPL protein promotes Dexa/BV6-mediated cell death, thereby providing novel insights into the synergistic antitumor activity of this combination treatment.
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Affiliation(s)
- Lara Kleinesudeik
- Institute for Experimental Cancer Research in Pediatrics, Goethe-University, Frankfurt, Germany.,German Cancer Consortium (DKTK), Partner site Frankfurt, Germany.,German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Katharina Rohde
- Institute for Experimental Cancer Research in Pediatrics, Goethe-University, Frankfurt, Germany
| | - Simone Fulda
- Institute for Experimental Cancer Research in Pediatrics, Goethe-University, Frankfurt, Germany.,German Cancer Consortium (DKTK), Partner site Frankfurt, Germany.,German Cancer Research Center (DKFZ), Heidelberg, Germany
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7
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Yu X, Ling J, Liu X, Guo S, Lin Y, Liu X, Su L. Cordycepin induces autophagy-mediated c-FLIPL degradation and leads to apoptosis in human non-small cell lung cancer cells. Oncotarget 2018; 8:6691-6699. [PMID: 28035061 PMCID: PMC5351663 DOI: 10.18632/oncotarget.14262] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Accepted: 12/01/2016] [Indexed: 02/05/2023] Open
Abstract
Cordycepin, a main active composition extracted from Cordyceps militaris, has been reported to exert anti-tumor activity in a broad spectrum of cancer types. However, the function of cordycepin on human non-small cell lung cancer cells is still obscure. Our present work showed that cordycepin inhibited cell growth by inducing apoptosis and autophagy in human NSCLC cells. Further study revealed that cordycepin triggered extrinsic apoptosis associated with down-regulation of c-FLIPL which suppresses the activity of caspase-8. And ectopic expression of c-FLIPL dramatically prevented cordycepin-caused apoptosis. Meanwhile, cordycepin stimulated autophagy through suppressing mTOR signaling pathway in lung cancer cells. When autophagy was blocked by Atg5 siRNA or PI3K inhibitor LY294002, the levels of apoptosis caused by cordycepin were obviously attenuated. In addition, suppression of autophagy could also elevate the level of c-FLIPL which indicated cordycepin-triggered autophagy promoted the degradation of c-FLIPL. Therefore, we conclude that cordycepin induces apoptosis through autophagy-mediated downregulation of c-FLIPL in human NSCLC cells. Taken together, our findings provide a novel prospect on the anti-tumor property of cordycepin, which may further prompt cordycepin to serve as a promising therapeutic approach in NSCLC treatment.
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Affiliation(s)
- Xinghui Yu
- Shandong Provincial Key Laboratory of Animal Cells and Developmental Biology, Shandong University School of Life Sciences, Jinan, China
| | - Jianya Ling
- Shandong Provincial Key Laboratory of Animal Cells and Developmental Biology, Shandong University School of Life Sciences, Jinan, China
| | - Xianfang Liu
- The Department of Otolaryngology Head and Neck Surgery, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, China
| | - Sen Guo
- Shandong Provincial Key Laboratory of Animal Cells and Developmental Biology, Shandong University School of Life Sciences, Jinan, China
| | - Yidan Lin
- The Thoracic Surgery Department of West China Hospital, West China Medical School of Sichuan University, Chengdu, China
| | - Xiangguo Liu
- Shandong Provincial Key Laboratory of Animal Cells and Developmental Biology, Shandong University School of Life Sciences, Jinan, China
| | - Ling Su
- Shandong Provincial Key Laboratory of Animal Cells and Developmental Biology, Shandong University School of Life Sciences, Jinan, China
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8
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Oh YT, Deng L, Deng J, Sun SY. The proteasome deubiquitinase inhibitor b-AP15 enhances DR5 activation-induced apoptosis through stabilizing DR5. Sci Rep 2017; 7:8027. [PMID: 28808321 PMCID: PMC5556018 DOI: 10.1038/s41598-017-08424-w] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2017] [Accepted: 07/07/2017] [Indexed: 01/25/2023] Open
Abstract
b-AP15 and its derivatives block proteasome deubiquitinase (DUB) activity and have been developed and tested in the clinic as potential cancer therapeutic agents. b-AP15 induces apoptosis in cancer cells, but the underlying mechanisms are largely undefined. The current study focuses on studying the modulatory effects of b-AP15 on death receptor 5 (DR5) levels and DR5 activation-induced apoptosis as well as on understanding the underlying mechanisms. Treatment with b-AP15 potently increased DR5 levels including cell surface DR5 in different cancer cell lines with limited or no effects on the levels of other related proteins including DR4, c-FLIP, FADD, and caspase-8. b-AP15 substantially slowed the degradation of DR5, suggesting that it stabilizes DR5. Moreover, b-AP15 effectively augmented apoptosis when combined with TRAIL or the DR5 agonistic antibody AMG655; these effects are DR5-dependent because DR5 deficiency abolished the ability of b-AP15 to enhance TRAIL- or AMG655-induced apoptosis. Therefore, it is clear that b-AP15, and possibly its derivatives, can stabilize DR5 and increase functional cell surface DR5 levels, resulting in enhancement of DR5 activation-induced apoptosis. Our findings suggest that b-AP15 and its derivatives may have potential in sensitizing cancer cells to DR5 activation-based cancer therapy.
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Affiliation(s)
- You-Take Oh
- Department of Hematology and Medical Oncology, Winship Cancer Institute, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Liang Deng
- Department of Hematology and Medical Oncology, Winship Cancer Institute, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Jiusheng Deng
- Department of Hematology and Medical Oncology, Winship Cancer Institute, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Shi-Yong Sun
- Department of Hematology and Medical Oncology, Winship Cancer Institute, Emory University School of Medicine, Atlanta, Georgia, USA.
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9
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Gates LT, Shisler JL. cFLIPL Interrupts IRF3-CBP-DNA Interactions To Inhibit IRF3-Driven Transcription. THE JOURNAL OF IMMUNOLOGY 2016; 197:923-33. [PMID: 27342840 DOI: 10.4049/jimmunol.1502611] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2015] [Accepted: 05/26/2016] [Indexed: 12/17/2022]
Abstract
Type I IFN induction is critical for antiviral and anticancer defenses. Proper downregulation of type I IFN is equally important to avoid deleterious imbalances in the immune response. The cellular FLIP long isoform protein (cFLIPL) controls type I IFN production, but opposing publications show it as either an inhibitor or inducer of type I IFN synthesis. Regardless, the mechanistic basis for cFLIPL regulation is unknown. Because cFLIPL is important in immune cell development and proliferation, and is a target for cancer therapies, it is important to identify how cFLIPL regulates type I IFN production. Data in this study show that cFLIPL inhibits IFN regulatory factor 3 (IRF3), a transcription factor central for IFN-β and IFN-stimulated gene expression. This inhibition occurs during virus infection, cellular exposure to polyinosinic-polycytidylic acid, or TBK1 overexpression. This inhibition is independent of capase-8 activity. cFLIPL binds to IRF3 and disrupts IRF3 interaction with its IFN-β promoter and its coactivator protein (CREB-binding protein). Mutational analyses reveal that cFLIPL nuclear localization is necessary and sufficient for inhibitory function. This suggests that nuclear cFLIPL prevents IRF3 enhanceosome formation. Unlike other cellular IRF3 inhibitors, cFLIPL did not degrade or dephosphorylate IRF3. Thus, cFLIPL represents a different cellular strategy to inhibit type I IFN production. This new cFLIPL function must be considered to accurately understand how cFLIPL affects immune system development and regulation.
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Affiliation(s)
- Lauren T Gates
- Department of Microbiology, University of Illinois at Urbana-Champaign, Urbana, IL 61801
| | - Joanna L Shisler
- Department of Microbiology, University of Illinois at Urbana-Champaign, Urbana, IL 61801
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10
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Yao W, Yue P, Khuri FR, Sun SY. The BET bromodomain inhibitor, JQ1, facilitates c-FLIP degradation and enhances TRAIL-induced apoptosis independent of BRD4 and c-Myc inhibition. Oncotarget 2015; 6:34669-79. [PMID: 26415225 PMCID: PMC4741481 DOI: 10.18632/oncotarget.5785] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2015] [Accepted: 08/31/2015] [Indexed: 12/22/2022] Open
Abstract
Inhibition of BET bromodomains (BRDs) has emerged as a promising cancer therapeutic strategy. Accordingly, inhibitors of BRDs such as JQ1 have been actively developed and some have reached clinical testing. However, the mechanisms by which this group of inhibitors exerts their anticancer activity, including induction of apoptosis, have not been fully elucidated. This report reveals a previously uncovered activity of JQ1 in inducing c-FLIP degradation and enhancing TRAIL-induced apoptosis. JQ1 potently decreased c-FLIP (both long and short forms) levels in multiple cancer cell lines without apparently increasing the expression of DR5 and DR4. Consequently, JQ1, when combined with TRAIL, synergistically induced apoptosis; this enhanced apoptosis-inducing activity could be abolished by enforced expression of ectopic FLIPL or FLIPS. Hence it appears that JQ1 decreases c-FLIP levels, resulting in enhancement of TRAIL-induced apoptosis. Inhibition of proteasome with MG132 prevented JQ1-induced c-FLIP reduction. Moreover, JQ1 decreased c-FLIP stability. Therefore, JQ1 apparently decreases c-FLIP levels through facilitating its proteasomal degradation. Genetic inhibition of either BRD4 or c-Myc by knocking down their expression failed to mimic JQ1 in decreasing c-FLIP and enhancing TRAIL-induced apoptosis, suggesting that JQ1 induces c-FLIP degradation and enhances TRAIL-induced apoptosis independent of BRD4 or c-Myc inhibition. In summary, our findings in this study highlights a novel biological function of JQ1 in modulating apoptosis and warrant further study of the potential treatment of cancer with the JQ1 and TRAIL combination.
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Affiliation(s)
- Weilong Yao
- Department of Respiration, Xiangya Hospital and Xiangya School of Medicine, Central South University, Changsha, Hunan, PR China
- Department of Hematology and Medical Oncology, Winship Cancer Institute, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Ping Yue
- Department of Hematology and Medical Oncology, Winship Cancer Institute, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Fadlo R. Khuri
- Department of Hematology and Medical Oncology, Winship Cancer Institute, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Shi-Yong Sun
- Department of Hematology and Medical Oncology, Winship Cancer Institute, Emory University School of Medicine, Atlanta, Georgia, USA
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11
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Expression of tumor necrosis factor-related apoptosis-inducing ligand death receptors DR4 and DR5 in human nonmelanoma skin cancer. Am J Dermatopathol 2015; 36:710-7. [PMID: 24212133 DOI: 10.1097/dad.0b013e3182a3d31d] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Death receptors 4 and 5 (DR4 and DR5) are cell surface receptors that when activated by their ligand tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) triggers apoptosis in most cancer cells but not in normal cells. Currently, it remains unclear whether DR4 and DR5 are involved in immune surveillance against nonmelanoma skin cancer (NMSC) progression. The aim of this study was to investigate the expression of DR4 and DR5 in NMSC and relate the results to the established clinicopathologic prognostic factors. This study was conducted on about 80 skin specimens from patients with NMSC (40 basal cell carcinoma and 40 squamous cell carcinoma) and diagnosed and confirmed by biopsy. Immunohistochemical analysis for DR4 and DR5 was carried out on formalin-fixed paraffin-embedded sections of skin tissues using avidin-biotin peroxidase method. Significant expression of both DR4 and DR5 was observed in NMSC cases. There was statistically significant association between DR4 and DR5 expression in squamous cell carcinoma and each of tumor site and lymph node metastasis. There was statistically significant association between DR4 expression in basal cell carcinoma and histopathologic subtypes (high expression in nodular type) and between DR5 expression and tumor site (high expression in sun-exposed area). In conclusion, expression of TRAIL receptors that mediate extrinsic apoptotic pathway in NMSC may be suggestive of a reassessment of the suitability of TRAIL-based strategy in future NMSC therapies.
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12
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Wang H, Yang S, Zhou H, Sun M, Du L, Wei M, Luo M, Huang J, Deng H, Feng Y, Huang J, Zhou Y. Aloperine executes antitumor effects against multiple myeloma through dual apoptotic mechanisms. J Hematol Oncol 2015; 8:26. [PMID: 25886453 PMCID: PMC4377192 DOI: 10.1186/s13045-015-0120-x] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2014] [Accepted: 02/11/2015] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Aloperine, a natural alkaloid constituent isolated from the herb Sophora alopecuroides displays anti-inflammatory properties in vitro and in vivo. Our group previously demonstrated that aloperine significantly induced apoptosis in colon cancer SW480 and HCT116 cells. However, its specific target(s) remain to be discovered in multiple myeloma (MM) and have not been investigated. METHODS Human myeloma cell lines (n = 8), primary myeloma cells (n = 12), drug-resistant myeloma cell lines (n = 2), and animal models were tested for their sensitivity to aloperine in terms of proliferation and apoptosis both in vitro and in vivo, respectively. We also examined the functional mechanisms underlying the apoptotic pathways triggered by aloperine. RESULTS Aloperine induced MM cell death in a dose- and time-dependent manner, even in the presence of the proliferative cytokines interleukin-6 and insulin-like growth factor I. Mechanistic studies revealed that aloperine not only activated caspase-8 and reduced the expression of FADD-like interleukin-1β-converting enzyme (FLICE)-like inhibitory protein long (FLIPL) and FLICE-inhibitory proteins (FLIPS) but also activated caspase-9 and decreased the expression of phosphorylated (p)-PTEN. Moreover, co-activation of the caspase-8/cellular FLICE-inhibitory protein (cFLIP)- and caspase-9/p-PTEN/p-AKT-dependent apoptotic pathways by aloperine caused irreversible inhibition of clonogenic survival. Aloperine induce more MM apoptosis with tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) or borterzomib. A U266 xenograft tumor model and 5T33 MM cells recapitulated the antitumor efficacy of aloperine, and the animals displayed excellent tolerance of the drug and few adverse effects. CONCLUSIONS Aloperine has multifaceted antitumor effects on MM cells. Our data support the clinical development of aloperine for MM therapy.
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Affiliation(s)
- He Wang
- Department of Oncology, The Second Affiliated Hospital of Guangzhou Medical University, Guangzhou, Guangdong, 510260, China.
- College of Pharmaceutics Science, Guangzhou Medical University, Guangzhou, Guangdong, 510182, China.
| | - Shu Yang
- Department of Oncology, The First Affiliated Hospital of Guangdong Pharmaceutical University, Guangzhou, Guangdong, 510080, China.
| | - Hong Zhou
- The Second Affiliated Hospital of Guangzhou University of Traditional Chinese Medicine, Guangzhou, Guangdong, 510521, China.
| | - Mingna Sun
- College of Pharmaceutics Science, Guangzhou Medical University, Guangzhou, Guangdong, 510182, China.
| | - Lingran Du
- College of Pharmaceutics Science, Guangzhou Medical University, Guangzhou, Guangdong, 510182, China.
| | - Minyan Wei
- College of Pharmaceutics Science, Guangzhou Medical University, Guangzhou, Guangdong, 510182, China.
| | - Meixia Luo
- College of Pharmaceutics Science, Guangzhou Medical University, Guangzhou, Guangdong, 510182, China.
| | - Jingzhu Huang
- College of Pharmaceutics Science, Guangzhou Medical University, Guangzhou, Guangdong, 510182, China.
| | - Hongzhu Deng
- School of the Traditional Chinese Medicine, Southern Medical University, Guangzhou, Guangdong, 510515, China.
| | - Yinghong Feng
- College of Pharmaceutics Science, Guangzhou Medical University, Guangzhou, Guangdong, 510182, China.
| | - Jun Huang
- College of Basic Medicine, Guangzhou Medical University, Guangzhou, Guangdong, 510182, China.
| | - Yi Zhou
- College of Pharmaceutics Science, Guangzhou Medical University, Guangzhou, Guangdong, 510182, China.
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13
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Tamura D, Saito T, Murata K, Kawashima M, Asano R. Celecoxib exerts antitumor effects in canine mammary tumor cells via COX‑2‑independent mechanisms. Int J Oncol 2015; 46:1393-404. [PMID: 25571853 DOI: 10.3892/ijo.2015.2820] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2014] [Accepted: 12/05/2014] [Indexed: 11/06/2022] Open
Abstract
Celecoxib plays antitumor roles via multiple mechanisms in a variety of human cancers. The aim of this study was to clarify the mechanism of action of celecoxib in canine mammary tumors. We examined the antitumor effects of celecoxib in AZACB canine mammary tumor cells expressing low levels of cyclooxygenase‑2 (COX‑2) to minimize the effect of COX‑2 on its activity. Our data revealed that celecoxib inhibited cell proliferation mainly via COX‑2‑independent mechanisms. Specifically, celecoxib decreased the proportion of cells in S phase and increased G2/M arrest, which was associated with increased expression of the cyclin‑dependent kinase inhibitors (CDKIs) p21 and p27. In addition, treatment with celecoxib downregulated COX‑2 expression, and induced apoptosis via both the intrinsic and extrinsic pathways. These findings suggest that celecoxib might be a useful agent for the treatment of canine mammary tumors, regardless of COX‑2 expression. In the future, it might be possible to use a combination of celecoxib and other antitumor agents to treat canine mammary tumors.
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Affiliation(s)
- Dai Tamura
- Laboratory of Veterinary Pharmacology, Nihon University College of Bioresource Sciences, Fujisawa, Kanagawa 252‑8510, Japan
| | - Teruyoshi Saito
- Laboratory of Veterinary Pharmacology, Nihon University College of Bioresource Sciences, Fujisawa, Kanagawa 252‑8510, Japan
| | - Kanae Murata
- Laboratory of Veterinary Pharmacology, Nihon University College of Bioresource Sciences, Fujisawa, Kanagawa 252‑8510, Japan
| | - Masafumi Kawashima
- Laboratory of Veterinary Pharmacology, Nihon University College of Bioresource Sciences, Fujisawa, Kanagawa 252‑8510, Japan
| | - Ryuji Asano
- Laboratory of Veterinary Pharmacology, Nihon University College of Bioresource Sciences, Fujisawa, Kanagawa 252‑8510, Japan
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14
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Mitochondrial inhibitor sensitizes non-small-cell lung carcinoma cells to TRAIL-induced apoptosis by reactive oxygen species and Bcl-X(L)/p53-mediated amplification mechanisms. Cell Death Dis 2014; 5:e1579. [PMID: 25522273 PMCID: PMC4649849 DOI: 10.1038/cddis.2014.547] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2014] [Revised: 11/13/2014] [Accepted: 11/17/2014] [Indexed: 12/20/2022]
Abstract
Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is a promising agent for anticancer therapy; however, non-small-cell lung carcinoma (NSCLC) cells are relatively TRAIL resistant. Identification of small molecules that can restore NSCLC susceptibility to TRAIL-induced apoptosis is meaningful. We found here that rotenone, as a mitochondrial respiration inhibitor, preferentially increased NSCLC cells sensitivity to TRAIL-mediated apoptosis at subtoxic concentrations, the mechanisms by which were accounted by the upregulation of death receptors and the downregulation of c-FLIP (cellular FLICE-like inhibitory protein). Further analysis revealed that death receptors expression by rotenone was regulated by p53, whereas c-FLIP downregulation was blocked by Bcl-XL overexpression. Rotenone triggered the mitochondria-derived reactive oxygen species (ROS) generation, which subsequently led to Bcl-XL downregulation and PUMA upregulation. As PUMA expression was regulated by p53, the PUMA, Bcl-XL and p53 in rotenone-treated cells form a positive feedback amplification loop to increase the apoptosis sensitivity. Mitochondria-derived ROS, however, promote the formation of this amplification loop. Collectively, we concluded that ROS generation, Bcl-XL and p53-mediated amplification mechanisms had an important role in the sensitization of NSCLC cells to TRAIL-mediated apoptosis by rotenone. The combined TRAIL and rotenone treatment may be appreciated as a useful approach for the therapy of NSCLC that warrants further investigation.
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ZHANG HONG, LI ZHIHONG, WANG KAIZHONG, REN PING. Combined treatment of XIAP-targeting shRNA and celecoxib synergistically inhibits the tumor growth of non-small cell lung cancer cells in vitro and in vivo. Oncol Rep 2014; 33:1079-88. [DOI: 10.3892/or.2014.3678] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2014] [Accepted: 07/16/2014] [Indexed: 11/05/2022] Open
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Wang B, Xie M, Li R, Owonikoko TK, Ramalingam SS, Khuri FR, Curran WJ, Wang Y, Deng X. Role of Ku70 in deubiquitination of Mcl-1 and suppression of apoptosis. Cell Death Differ 2014; 21:1160-9. [PMID: 24769731 DOI: 10.1038/cdd.2014.42] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2013] [Revised: 02/17/2014] [Accepted: 03/06/2014] [Indexed: 01/12/2023] Open
Abstract
Mcl-1 is a unique antiapoptotic Bcl2 family member with a short half-life due to its rapid turnover through ubiquitination. We discovered that Ku70, a DNA double-strand break repair protein, functions as a deubiquitinase to stabilize Mcl-1. Ku70 knockout in mouse embryonic fibroblast (MEF) cells or depletion from human lung cancer H1299 cells leads to the accumulation of polyubiquitinated Mcl-1 and a reduction in its half-life and protein expression. Conversely, expression of exogenous Ku70 in Ku70(-/-) MEF cells restores Mcl-1 expression. Subcellular fractionation indicates that Ku70 extensively colocalizes with Mcl-1 in mitochondria, endoplasmic reticulum and nucleus in H1299 cells. Ku70 directly interacts with Mcl-1 via its C terminus (that is, aa 536-609), which is required and sufficient for deubiquitination and stabilization of Mcl-1, leading to suppression of apoptosis. Purified Ku70 protein directly deubiquitinates Mcl-1 by removing K48-linked polyubiquitin chains. Ku70 knockdown not only promotes Mcl-1 turnover but also enhances antitumor efficacy of the BH3-mimetic ABT-737 in human lung cancer xenografts. These findings identify Ku70 as a novel Mcl-1 deubiquitinase that could be a potential target for cancer therapy by manipulating Mcl-1 deubiquitination.
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Affiliation(s)
- B Wang
- Division of Cancer Biology, Department of Radiation Oncology, Emory University School of Medicine and Winship Cancer Institute of Emory University, Atlanta, GA 30322, USA
| | - M Xie
- Division of Cancer Biology, Department of Radiation Oncology, Emory University School of Medicine and Winship Cancer Institute of Emory University, Atlanta, GA 30322, USA
| | - R Li
- Division of Cancer Biology, Department of Radiation Oncology, Emory University School of Medicine and Winship Cancer Institute of Emory University, Atlanta, GA 30322, USA
| | - T K Owonikoko
- Hematology and Medical Oncology, Emory University School of Medicine and Winship Cancer Institute of Emory University, Atlanta, GA 30322, USA
| | - S S Ramalingam
- Hematology and Medical Oncology, Emory University School of Medicine and Winship Cancer Institute of Emory University, Atlanta, GA 30322, USA
| | - F R Khuri
- Hematology and Medical Oncology, Emory University School of Medicine and Winship Cancer Institute of Emory University, Atlanta, GA 30322, USA
| | - W J Curran
- Division of Cancer Biology, Department of Radiation Oncology, Emory University School of Medicine and Winship Cancer Institute of Emory University, Atlanta, GA 30322, USA
| | - Y Wang
- Division of Cancer Biology, Department of Radiation Oncology, Emory University School of Medicine and Winship Cancer Institute of Emory University, Atlanta, GA 30322, USA
| | - X Deng
- Division of Cancer Biology, Department of Radiation Oncology, Emory University School of Medicine and Winship Cancer Institute of Emory University, Atlanta, GA 30322, USA
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Koo J, Yue P, Gal AA, Khuri FR, Sun SY. Maintaining glycogen synthase kinase-3 activity is critical for mTOR kinase inhibitors to inhibit cancer cell growth. Cancer Res 2014; 74:2555-68. [PMID: 24626091 DOI: 10.1158/0008-5472.can-13-2946] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
mTOR kinase inhibitors that target both mTORC1 and mTORC2 are being evaluated in cancer clinical trials. Here, we report that glycogen synthase kinase-3 (GSK3) is a critical determinant for the therapeutic response to this class of experimental drugs. Pharmacologic inhibition of GSK3 antagonized their suppressive effects on the growth of cancer cells similarly to genetic attenuation of GSK3. Conversely, expression of a constitutively activated form of GSK3β sensitized cancer cells to mTOR inhibition. Consistent with these findings, higher basal levels of GSK3 activity in a panel of human lung cancer cell lines correlated with more efficacious responses. Mechanistic investigations showed that mTOR kinase inhibitors reduced cyclin D1 levels in a GSK3β-dependent manner, independent of their effects on suppressing mTORC1 signaling and cap binding. Notably, selective inhibition of mTORC2 triggered proteasome-mediated cyclin D1 degradation, suggesting that mTORC2 blockade is responsible for GSK3-dependent reduction of cyclin D1. Silencing expression of the ubiquitin E3 ligase FBX4 rescued this reduction, implicating FBX4 in mediating this effect of mTOR inhibition. Together, our findings define a novel mechanism by which mTORC2 promotes cell growth, with potential implications for understanding the clinical action of mTOR kinase inhibitors.
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Affiliation(s)
- Junghui Koo
- Authors' Affiliations: Departments of Hematology and Medical Oncology and Pathology, Emory University School of Medicine and Winship Cancer Institute, Atlanta, Georgia
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18
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Li T, Su L, Zhong N, Hao X, Zhong D, Singhal S, Liu X. Salinomycin induces cell death with autophagy through activation of endoplasmic reticulum stress in human cancer cells. Autophagy 2013; 9:1057-68. [PMID: 23670030 PMCID: PMC3722315 DOI: 10.4161/auto.24632] [Citation(s) in RCA: 109] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Salinomycin is perhaps the first promising compound that was discovered through high throughput screening in cancer stem cells. This novel agent can selectively eliminate breast and other cancer stem cells, though the mechanism of action remains unclear. In this study, we found that salinomycin induced autophagy in human non-small cell lung cancer (NSCLC) cells. Furthermore, we demonstrated that salinomycin stimulated endoplasmic reticulum stress and mediated autophagy via the ATF4-DDIT3/CHOP-TRIB3-AKT1-MTOR axis. Moreover, we found that the autophagy induced by salinomycin played a prosurvival role in human NSCLC cells and attenuated the apoptotic cascade. We also showed that salinomycin triggered more apoptosis and less autophagy in A549 cells in which CDH1 expression was inhibited, suggesting that the inhibition of autophagy might represent a promising strategy to target cancer stem cells. In conclusion, these findings provide evidence that combination treatment with salinomycin and pharmacological autophagy inhibitors will be an effective therapeutic strategy for eliminating cancer cells as well as cancer stem cells.
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Affiliation(s)
- Tianliang Li
- Key Laboratory for Experimental Teratology of the Ministry of Education and School of Life Sciences; Shandong University; Jinan, China
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Yang L, Su L, Cao C, Xu L, Zhong D, Xu L, Liu X. The chalcone 2′-hydroxy-4′,5′-dimethoxychalcone activates death receptor 5 pathway and leads to apoptosis in human nonsmall cell lung cancer cells. IUBMB Life 2013; 65:533-43. [DOI: 10.1002/iub.1161] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2012] [Revised: 02/05/2013] [Accepted: 02/06/2013] [Indexed: 12/12/2022]
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Zhao L, Yue P, Khuri FR, Sun SY. mTOR complex 2 is involved in regulation of Cbl-dependent c-FLIP degradation and sensitivity of TRAIL-induced apoptosis. Cancer Res 2013; 73:1946-57. [PMID: 23319802 DOI: 10.1158/0008-5472.can-12-3710] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
The mTOR positively regulates cell proliferation and survival through forming 2 complexes with raptor (mTOR complex 1; mTORC1) or rictor (mTOR complex 2; mTORC2). Compared with the mTORC1, relatively little is known about the biologic functions of mTORC2. This study focuses on addressing whether mTORC2 regulates apoptosis, particularly induced by TRAIL (TNFSF10). Using the mTOR kinase inhibitor, PP242, as a research tool, we found that it synergized with TRAIL to augment apoptosis of cancer cells. PP242 reduced the abundance of the short form of c-FLIP (FLIP(S), CFLAR(S)) and survivin (BIRC5). Enforced expression of ectopic FLIP(S), but not survivin, attenuated augmented apoptosis induced by PP242 plus TRAIL. Thus, it is FLIP(S) downregulation that contributes to synergistic induction of apoptosis by PP242 plus TRAIL. PP242 decreased FLIP(S) stability, increased FLIP(S) ubiquitination, and facilitated FLIP(S) degradation. Moreover, knockdown of the E3 ligase Cbl (CBL) abolished PP242-induced FLIP(S) reduction. Thus, PP242 induces Cbl-dependent degradation of FLIP(S), leading to FLIP(S) downregulation. Consistently, knockdown of rictor or mTOR, but not raptor, mimicked PP242 in decreasing FLIP(S) levels and sensitizing cells to TRAIL. Rictor knockdown decreased FLIP(S) stability, whereas enforced expression of rictor stabilized FLIP(S). Moreover, silencing of Cbl abrogated FLIP(S) reduction induced by rictor knockdown. Collectively we conclude that it is mTORC2 inhibition that results in FLIP(S) downregulation and subsequent sensitization of TRAIL-induced apoptosis. Our findings provide the first evidence showing that mTORC2 stabilizes FLIP(S), hence connecting mTORC2 signaling to the regulation of death receptor-mediated apoptosis.
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Affiliation(s)
- Liqun Zhao
- Department of Hematology and Medical Oncology, Emory University School of Medicine and Winship Cancer Institute, Atlanta, Georgia 30322, USA
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21
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Wang Q, Sun W, Hao X, Li T, Su L, Liu X. Down-regulation of cellular FLICE-inhibitory protein (Long Form) contributes to apoptosis induced by Hsp90 inhibition in human lung cancer cells. Cancer Cell Int 2012; 12:54. [PMID: 23256568 PMCID: PMC3558364 DOI: 10.1186/1475-2867-12-54] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2012] [Accepted: 12/20/2012] [Indexed: 02/08/2023] Open
Abstract
Background Cellular FLICE-Inhibitory Protein (long form, c-FLIPL) is a critical negative regulator of death receptor-mediated apoptosis. Overexpression of c-FLIPL has been reported in many cancer cell lines and is associated with chemoresistance. In contrast, down-regulation of c-FLIP may drive cancer cells into cellular apoptosis. This study aims to demonstrate that inhibition of the heat shock protein 90 (Hsp90) either by inhibitors geldanamycin/17-N-Allylamino-17-demethoxygeldanamycin (GA/17-AAG) or siRNA technique in human lung cancer cells induces c-FLIPL degradation and cellular apoptosis through C-terminus of Hsp70-interacting protein (CHIP)-mediated mechanisms. Methods Calu-1 and H157 cell lines (including H157-c-FLIPL overexpressing c-FLIPL and control cell H157-lacZ) were treated with 17-AAG and the cell lysates were prepared to detect the given proteins by Western Blot and the cell survival was assayed by SRB assay. CHIP and Hsp90 α/β proteins were knocked down by siRNA technique. CHIP and c-FLIPL plasmids were transfected into cells and immunoprecipitation experiments were performed to testify the interactions between c-FLIPL, CHIP and Hsp90. Results c-FLIPL down-regulation induced by 17-AAG can be reversed with the proteasome inhibitor MG132, which suggested that c-FLIPL degradation is mediated by a ubiquitin-proteasome system. Inhibition of Hsp90α/β reduced c-FLIPL level, whereas knocking down CHIP expression with siRNA technique inhibited c-FLIPL degradation. Furthermore, c-FLIPL and CHIP were co-precipitated in the IP complexes. In addition, overexpression of c-FLIPL can rescue cancer cells from apoptosis. When 17-AAG was combined with an anti-cancer agent celecoxib(CCB), c-FLIPL level declined further and there was a higher degree of caspase activation. Conclusion We have elucidated c-FLIPL degradation contributes to apoptosis induced by Hsp90 inhibition, suggesting c-FLIP and Hsp90 may be the promising combined targets in human lung cancer treatment.
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Affiliation(s)
- Qilin Wang
- Key Laboratory for Experimental Teratology of the Ministry of Education and School of Life Sciences, Shandong University, Jinan, China.,Liaocheng University School of Life Sciences, Liaocheng, China
| | - Wendong Sun
- The Second Hospital, Shandong University, Jinan, China
| | - Xuexi Hao
- The Second Hospital, Shandong University, Jinan, China
| | - Tianliang Li
- Key Laboratory for Experimental Teratology of the Ministry of Education and School of Life Sciences, Shandong University, Jinan, China
| | - Ling Su
- Key Laboratory for Experimental Teratology of the Ministry of Education and School of Life Sciences, Shandong University, Jinan, China
| | - Xiangguo Liu
- Key Laboratory for Experimental Teratology of the Ministry of Education and School of Life Sciences, Shandong University, Jinan, China.,Shandong University School of Life Sciences, Room103, South Building, 27 Shandananlu Road, Jinan, 250100, China
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Xu L, Su L, Liu X. PKCδ regulates death receptor 5 expression induced by PS-341 through ATF4-ATF3/CHOP axis in human lung cancer cells. Mol Cancer Ther 2012; 11:2174-82. [PMID: 22848091 DOI: 10.1158/1535-7163.mct-12-0602] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PS-341 (bortezomib), a proteasome inhibitor, has been approved for the treatment of multiple myeloma. Our previous work has shown that PS-341 induces death receptor 5 (DR5)-dependent apoptosis and enhances the TNF-related apoptosis-inducing ligand-induced apoptosis in human non-small cell lung cancer cells. However, the definite mechanism remains undefined. In the present study, we reveal that PKCδ and RSK2 mediate PS-341-induced DR5 upregulation, involving coactivation of endoplasmic reticulum (ER) stress. We discovered that PS-341 activated ER stress through elevating the expression of BiP, p-eIF2α, IRE1α, ATF4, ATF3, and CCAAT/enhancer-binding protein homologous protein (CHOP). Further study showed that DR5 upregulation was dependent on ATF4, ATF3, and CHOP expression. Silencing either one of the ATF4, ATF3, and CHOP expression decreased DR5 upregulation and subsequent apoptosis. We determined that ATF4 regulated ATF3 and CHOP expression. Thereafter, ATF3 and CHOP formed a complex and regulated DR5 expression. In addition, we discovered that the phosphorylation of extracellular signal-regulated kinase (ERK) 1/2 and RSK2 were elevated after PS-341 treatment and inhibition of their phosphorylation using MAP-ERK kinase 1/2 inhibitor decreased the DR5 level, indicating that ERK/RSK2 signaling is involved in DR5 upregulation. Furthermore, we detected the cleavage of PKCδ, and the blockage of PKCδ expression cut down DR5 upregulation and apoptosis. Importantly, knockdown of PKCδ expression decreased the induction of ER stress and the phosphorylation of ERK1/2 and RSK2, suggesting that PKCδ regulates DR5 expression through ERK/RSK2 signaling and ATF4-CHOP/ATF3 axis. Collectively, we show that PS-341 induces PKCδ-dependent DR5 expression through activation of ERK/RSK2 and ER stress signaling pathway.
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Affiliation(s)
- Linyan Xu
- Shandong University School of Life Sciences, Room 103, South Building, 27 Shanda South Road, Jinan, Shandong 250100, China
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Li B, Ren H, Yue P, Chen M, Khuri FR, Sun SY. The novel Akt inhibitor API-1 induces c-FLIP degradation and synergizes with TRAIL to augment apoptosis independent of Akt inhibition. Cancer Prev Res (Phila) 2012; 5:612-20. [PMID: 22345097 DOI: 10.1158/1940-6207.capr-11-0548] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
API-1 (pyrido[2,3-d]pyrimidines) is a novel small-molecule inhibitor of Akt, which acts by binding to Akt and preventing its membrane translocation and has promising preclinical antitumor activity. In this study, we reveal a novel function of API-1 in regulation of cellular FLICE-inhibitory protein (c-FLIP) levels and TRAIL-induced apoptosis, independent of Akt inhibition. API-1 effectively induced apoptosis in tested cancer cell lines including activation of caspase-8 and caspase-9. It reduced the levels of c-FLIP without increasing the expression of death receptor 4 (DR4) or DR5. Accordingly, it synergized with TRAIL to induce apoptosis. Enforced expression of ectopic c-FLIP did not attenuate API-1-induced apoptosis but inhibited its ability to enhance TRAIL-induced apoptosis. These data indicate that downregulation of c-FLIP mediates enhancement of TRAIL-induced apoptosis by API-1 but is not sufficient for API-1-induced apoptosis. API-1-induced reduction of c-FLIP could be blocked by the proteasome inhibitor MG132. Moreover, API-1 increased c-FLIP ubiquitination and decreased c-FLIP stability. These data together suggest that API-1 downregulates c-FLIP by facilitating its ubiquitination and proteasome-mediated degradation. Because other Akt inhibitors including API-2 and MK2206 had minimal effects on reducing c-FLIP and enhancement of TRAIL-induced apoptosis, it is likely that API-1 reduces c-FLIP and enhances TRAIL-induced apoptosis independent of its Akt-inhibitory activity.
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Affiliation(s)
- Bo Li
- Department of Hematology and Medical Oncology, Winship Cancer Institute, Emory University School of Medicine, Atlanta, Georgia 30322, USA
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Liu Y, Sun SY, Owonikoko TK, Sica GL, Curran WJ, Khuri FR, Deng X. Rapamycin induces Bad phosphorylation in association with its resistance to human lung cancer cells. Mol Cancer Ther 2011; 11:45-56. [PMID: 22057915 DOI: 10.1158/1535-7163.mct-11-0578] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Inhibition of mTOR signaling by rapamycin has been shown to activate extracellular signal-regulated kinase 1 or 2 (ERK1/2) and Akt in various types of cancer cells, which contributes to rapamycin resistance. However, the downstream effect of rapamycin-activated ERKs and Akt on survival or death substrate(s) remains unclear. We discovered that treatment of human lung cancer cells with rapamycin results in enhanced phosphorylation of Bad at serine (S) 112 and S136 but not S155 in association with activation of ERK1/2 and Akt. A higher level of Bad phosphorylation was observed in rapamycin-resistant cells compared with parental rapamycin-sensitive cells. Thus, Bad phosphorylation may contribute to rapamycin resistance. Mechanistically, rapamycin promotes Bad accumulation in the cytosol, enhances Bad/14-3-3 interaction, and reduces Bad/Bcl-XL binding. Rapamycin-induced Bad phosphorylation promotes its ubiquitination and degradation, with a significant reduction of its half-life (i.e., from 53.3-37.5 hours). Inhibition of MEK/ERK by PD98059 or depletion of Akt by RNA interference blocks rapamycin-induced Bad phosphorylation at S112 or S136, respectively. Simultaneous blockage of S112 and S136 phosphorylation of Bad by PD98059 and silencing of Akt significantly enhances rapamycin-induced growth inhibition in vitro and synergistically increases the antitumor efficacy of rapamycin in lung cancer xenografts. Intriguingly, either suppression of Bad phosphorylation at S112 and S136 sites or expression of the nonphosphorylatable Bad mutant (S112A/S136A) can reverse rapamycin resistance. These findings uncover a novel mechanism of rapamycin resistance, which may promote the development of new strategies for overcoming rapamycin resistance by manipulating Bad phosphorylation at S112 and S136 in human lung cancer.
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Affiliation(s)
- Yan Liu
- State Key Laboratory of Cancer Biology, Department of Biopharmaceutics, School of Pharmacy, Fourth Military Medical University, Xi'an, People's Republic of China
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Li LC, Jayaram S, Ganesh L, Qian L, Rotmensch J, Maker AV, Prabhakar BS. Knockdown of MADD and c-FLIP overcomes resistance to TRAIL-induced apoptosis in ovarian cancer cells. Am J Obstet Gynecol 2011; 205:362.e12-25. [PMID: 21855847 DOI: 10.1016/j.ajog.2011.05.035] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2011] [Revised: 05/11/2011] [Accepted: 05/18/2011] [Indexed: 12/31/2022]
Abstract
OBJECTIVE The clinical utility of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) in the treatment of established human malignancies is limited by the development of resistance to TRAIL. We hypothesized that knockdown of map-kinase activating death domain containing protein (MADD), a TRAIL-resistance factor, may overcome TRAIL resistance in ovarian cancer cells. STUDY DESIGN MADD expression in resected ovarian cancer specimens and cell lines was quantified with the use of polymerase chain reaction. Sensitivity of ovarian cancer cell lines to TRAIL, with or without MADD knockdown, was assessed. RESULTS MADD is expressed at relatively higher levels in human malignant ovarian cancer tissues and cell lines, compared with normal ovarian tissues. The cell lines OVCA429 and OVCAR3 were susceptible, and cell lines CAOV-3 and SKOV-3 were resistant to TRAIL. MADD knockdown in CAOV-3 cells, but not in SKOV-3 cells, conferred TRAIL sensitivity. Knockdown of cellular Fas-associated death domain-like interleukin-1 beta-converting enzyme-inhibitory protein (c-FLIP) in SKOV-3 cells increased spontaneous and TRAIL-induced apoptosis, which was further increased on MADD knockdown. CONCLUSION MADD/c-FLIP(L) knockdown can render TRAIL-resistant ovarian cancer cells susceptible to TRAIL.
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Stool-fermented Plantago ovata husk induces apoptosis in colorectal cancer cells independently of molecular phenotype. Br J Nutr 2011; 107:1591-602. [PMID: 22018732 DOI: 10.1017/s0007114511004910] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Several studies have suggested that the partially fermentable fibre Plantago ovata husk (PO) may have a protective effect on colorectal cancer (CRC). We studied the potentially pro-apoptotic effect of PO and the implicated mechanisms in CRC cells with different molecular phenotypes (Caco-2, HCT116, LoVo, HT-29, SW480) after PO anaerobic fermentation with colonic bacteria as it occurs in the human colon. The fermentation products of PO induced apoptosis in all primary tumour and metastatic cell lines, independent of p53, adenomatous polyposis coli, β-catenin or cyclo-oxygenase-2 status. Apoptosis was caspase-dependent and both intrinsic and extrinsic pathways were implicated. The intrinsic pathway was activated through a shift in the balance towards a pro-apoptotic environment with an up-regulation of B-cell lymphoma protein 2 homologous antagonist killer (BAK) and a down-regulation of B-cell lymphoma-extra large (Bcl-xL) seen in HCT116 and LoVo cells. This resulted in mitochondrial membrane depolarisation, increased expression of caspase activators second mitochondria-derived activator of caspases (Smac)/Diablo, death effector apoptosis-inducing factor, apoptosome member apoptotic protease activating factor 1 and down-regulation of inhibitors of apoptosis Survivin and X-linked inhibitor of apoptosis in most cells. The extrinsic pathway was activated presumably through the up-regulation of death receptor (DR5). Some important differences were seen between primary tumour and metastatic CRC cells. Thus, metastatic PO-treated LoVo cells had a remarkable up-regulation of TNF-α ligand along with death-inducing signalling complex components receptor interacting protein and TNF-α receptor 1-associated death domain protein. The extrinsic pathway modulator FCICE-inhibitory protein (FLIP), an inhibitor of both spontaneous death ligand-independent and death receptor-mediated apoptosis, was significantly down-regulated after PO treatment in all primary tumour cells, but not in metastatic LoVo. These findings suggest that PO could potentially be a useful chemotherapy adjuvant.
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Zhao L, Yue P, Lonial S, Khuri FR, Sun SY. The NEDD8-activating enzyme inhibitor, MLN4924, cooperates with TRAIL to augment apoptosis through facilitating c-FLIP degradation in head and neck cancer cells. Mol Cancer Ther 2011; 10:2415-25. [PMID: 21914854 DOI: 10.1158/1535-7163.mct-11-0401] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
TNF-related apoptosis-inducing ligand (TRAIL) is a tumor-selective cytokine with potential anticancer activity and is currently under clinical testing. Head and neck squamous cell carcinoma (HNSCC), like other cancer types, exhibits varied sensitivity to TRAIL. MLN4924 is a newly developed investigational small molecule inhibitor of NEDD8-activating enzyme with potent anticancer activity. This study reveals a novel function of MLN4924 in synergizing with TRAIL to induce apoptosis in HNSCC cells. MLN4924 alone effectively inhibited the growth of HNSCC cells and induced apoptosis. When combined with TRAIL, synergistic effects on decreasing the survival and inducing apoptosis of HNSCC cells occurred. MLN4924 decreased c-FLIP levels without modulating death receptor 4 and death receptor 5 expression. Enforced expression of c-FLIP substantially attenuated MLN4924/TRAIL-induced apoptosis. Thus c-FLIP reduction plays an important role in mediating MLN4924/TRAIL-induced apoptosis. Moreover, MLN4924 decreased c-FLIP stability, increased c-FLIP ubiquitination, and facilitated c-FLIP degradation, suggesting that MLN4924 decreases c-FLIP levels through promoting its degradation. MLN4924 activated c-jun-NH(2)-kinase (JNK) signaling, evidenced by increased levels of phospho-c-Jun in MLN4924-treated cells. Chemical inhibition of JNK activation not only prevented MLN4924-induced c-FLIP reduction, but also inhibited MLN4924/TRAIL-induced apoptosis, suggesting that JNK activation mediates c-FLIP downregulation and subsequent enhancement of TRAIL-induced apoptosis by MLN4924. Because knockdown of NEDD8 failed to activate JNK signaling and downregulate c-FLIP, it is likely that MLN4924 reduces c-FLIP levels and enhances TRAIL-induced apoptosis independent of NEDD8 inhibition.
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Affiliation(s)
- Liqun Zhao
- Department of Hematology and Medical Oncology, Emory University School of Medicine and Winship Cancer Institute, 1365-C Clifton Road NE, C3088, Atlanta, GA 30322, USA
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Chen S, Cao W, Yue P, Hao C, Khuri FR, Sun SY. Celecoxib promotes c-FLIP degradation through Akt-independent inhibition of GSK3. Cancer Res 2011; 71:6270-81. [PMID: 21868755 DOI: 10.1158/0008-5472.can-11-0838] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Celecoxib is a COX-2 inhibitor that reduces the risk of colon cancer. However, the basis for its cancer chemopreventive activity is not fully understood. In this study, we defined a mechanism of celecoxib action based on degradation of cellular FLICE-inhibitory protein (c-FLIP), a major regulator of the death receptor pathway of apoptosis. c-FLIP protein levels are regulated by ubiquitination and proteasome-mediated degradation. We found that celecoxib controlled c-FLIP ubiquitination through Akt-independent inhibition of glycogen synthase kinase-3 (GSK3), itself a candidate therapeutic target of interest in colon cancer. Celecoxib increased the levels of phosphorylated GSK3, including the α and β forms, even in cell lines, where phosphorylated Akt levels were not increased. Phosphoinositide 3-kinase inhibitors abrogated Akt phosphorylation as expected but had no effect on celecoxib-induced GSK3 phosphorylation. In contrast, protein kinase C (PKC) inhibitors abolished celecoxib-induced GSK3 phosphorylation, implying that celecoxib influenced GSK3 phosphorylation through a mechanism that relied upon PKC and not Akt. GSK3 blockade either by siRNA or kinase inhibitors was sufficient to attenuate c-FLIP levels. Combining celecoxib with GSK3 inhibition enhanced attenuation of c-FLIP and increased apoptosis. Proteasome inhibitor MG132 reversed the effects of GSK3 inhibition and increased c-FLIP ubiquitination, confirming that c-FLIP attenuation was mediated by proteasomal turnover as expected. Our findings reveal a novel mechanism through which the regulatory effects of c-FLIP on death receptor signaling are controlled by GSK3, which celecoxib acts at an upstream level to control independently of Akt.
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Affiliation(s)
- Shuzhen Chen
- Department of Hematology and Medical Oncology, Emory University School of Medicine and Winship Cancer Institute, Atlanta, Georgia 30322, USA
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Sung WW, Wang YC, Cheng YW, Lee MC, Yeh KT, Wang L, Wang J, Chen CY, Lee H. A Polymorphic −844T/C in FasL Promoter Predicts Survival and Relapse in Non–Small Cell Lung Cancer. Clin Cancer Res 2011; 17:5991-9. [DOI: 10.1158/1078-0432.ccr-11-0227] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Su L, Liu G, Hao X, Zhong N, Zhong D, Liu X, Singhal S. Death receptor 5 and cellular FLICE-inhibitory protein regulate pemetrexed-induced apoptosis in human lung cancer cells. Eur J Cancer 2011; 47:2471-8. [PMID: 21726997 DOI: 10.1016/j.ejca.2011.06.003] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2011] [Revised: 05/13/2011] [Accepted: 06/03/2011] [Indexed: 12/12/2022]
Abstract
Pemetrexed is a clinically available anti-folate therapeutic agent used in combination with cisplatin for the management of patients with malignant pleural mesothelioma and advanced non-small cell lung cancer. Pemetrexed inhibits three enzymes in purine and pyrimidine synthesis necessary for precursor DNA nucleotides which in turn disrupts growth and survival of normal and cancer cells. The mechanism by which pemetrexed induces apoptosis remains largely uncharacterised. In the current study, we examined the downstream effect of pemetrexed in inducing apoptosis in lung cancer cells. We showed that pemetrexed induced apoptosis via up-regulation of Death Receptor 5 (DR5), an important death receptor for tumour necrosis factor (TNF)-related apoptosis inducing ligand (TRAIL). In addition, we discovered a synergistic effect of combination pemetrexed and recombinant TRAIL in inducing apoptosis. Modulating DR5 induction by small interfering RNA abrogated the ability of pemetrexed to induce apoptosis. In addition, silencing of C/EBP homologous protein (CHOP) expression reduced DR5 expression, demonstrating that the transcriptional factor CHOP has a pivotal role on DR5 up-regulation following pemetrexed treatment. In addition, enforced expression of cellular FLICE-inhibitory protein (c-FLIP), a known inhibitor of caspase 8, protected neoplastic cells from apoptosis despite pemetrexed and/or TRAIL therapy. Thus, our findings demonstrate the efficacy and mechanistic underpinnings of pemetrexed-induced apoptosis, and they suggest pemetrexed may have clinical utility when used in combination with TRAIL for the management of patients with lung cancer.
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Affiliation(s)
- Ling Su
- School of Life Sciences, Shandong Provincial Key Laboratory Of Animal Cells and Developmental Biology, Shandong University, Jinan, People's Republic of China
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Ivanov VN, Partridge MA, Huang SXL, Hei TK. Suppression of the proinflammatory response of metastatic melanoma cells increases TRAIL-induced apoptosis. J Cell Biochem 2011; 112:463-75. [PMID: 21268068 DOI: 10.1002/jcb.22934] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Melanoma is the most lethal form of human skin cancer. However, only limited chemotherapy is currently available for the metastatic stage of the disease. Since chemotherapy, radiation and sodium arsenite treatment operate mainly through induction of the intrinsic mitochondrial pathway, a strongly decreased mitochondrial function in metastatic melanoma cells, could be responsible for low efficacy of the conventional therapy of melanoma. Another feature of metastatic melanoma cells is their proinflammatory phenotype, linked to endogenous expression of the inflammatory cytokines, such as TNFα IL6 and IL8, their receptors, and constitutive NF-κB- and STAT3-dependent gene expression, including cyclooxygenase-2 (PTGS2/COX2). In the present study, we treated melanoma cells with immunological (monoclonal antibody against TNFα or IL6), pharmacological (small molecular inhibitors of IKKβ-NF-κB and JAK2-STAT3) or genetic (specific RNAi for COX-2) agents that suppressed the inflammatory response in combination with induction of apoptosis via TRAIL. As a result of these combined treatments, exogenous TRAIL via interactions with TRAIL-R2/R1 strongly increased levels of apoptosis in resistant melanoma cells. The present study provides new understanding of the regulation of TRAIL-mediated apoptosis in melanoma and will serve as the foundation for the potential development of a novel approach for a therapy of resistant melanomas.
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Affiliation(s)
- Vladimir N Ivanov
- Department of Radiation Oncology, Center for Radiological Research, College of Physicians and Surgeons, Columbia University, New York, New York 10032, USA.
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Yu Z, Wang R, Xu L, Xie S, Dong J, Jing Y. β-Elemene piperazine derivatives induce apoptosis in human leukemia cells through downregulation of c-FLIP and generation of ROS. PLoS One 2011; 6:e15843. [PMID: 21283566 PMCID: PMC3026787 DOI: 10.1371/journal.pone.0015843] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2010] [Accepted: 11/26/2010] [Indexed: 01/16/2023] Open
Abstract
β-Elemene is an active component of the herb medicine Curcuma Wenyujin with reported antitumor activity. To improve its antitumor ability, five novel piperazine derivatives of β-elemene, 13-(3-methyl-1-piperazinyl)-β-elemene (DX1), 13-(cis-3,5-dimethyl-1-piperazinyl)-β-elemene (DX2), 13-(4-ethyl-1-piperazinyl)-β-elemene (DX3), 13-(4-isopropyl-1-piperazinyl)-β-elemene (DX4) and 13-piperazinyl-β-elemene (DX5), were synthesized. The antiproliferative and apoptotic effects of these derivatives were determined in human leukemia HL-60, NB4, K562 and HP100-1 cells. DX1, DX2 and DX5, which contain a secondary amino moiety, were more active in inhibiting cell growth and in inducing apoptosis than DX3 and DX4. The apoptosis induction ability of DX1 was associated with the generation of hydrogen peroxide (H2O2), a decrease of mitochondrial membrane potential (MMP), and the activation of caspase-8. Pretreatment with the antioxidants N-acetylcysteine and catalase completely blocked DX1-induced H2O2 production, but only partially its activation of caspase-8 and induction of apoptosis. HL-60 cells were more sensitive than its H2O2-resistant subclone HP100-1 cells to DX1-induced apoptosis. The activation of caspase-8 by these compounds was correlated with the decrease in the levels of cellular FLICE-inhibitory protein (c-FLIP). The proteasome inhibitor MG-132 augmented the decrease in c-FLIP levels and apoptosis induced by these derivatives. FADD- and caspase-8-deficient Jurkat subclones have a decreased response to DX1-induced apoptosis. Our data indicate that these novel β-elemene piperazine derivatives induce apoptosis through the decrease in c-FLIP levels and the production of H2O2 which leads to activation of both death receptor- and mitochondrial-mediated apoptotic pathways.
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Affiliation(s)
- Zhiying Yu
- School of Life Science and Biopharmaceutics, Shenyang Pharmaceutical University, Shenyang, China
| | - Rui Wang
- Department of Medicine, The Tisch Cancer Institute, Mount Sinai School of Medicine, New York, New York, United States of America
| | - Liying Xu
- Key Laboratory of Structure-Based Drug Design and Discovery, Ministry of Education, Shenyang Pharmaceutical University, Shenyang, China
| | - Siwei Xie
- Key Laboratory of Structure-Based Drug Design and Discovery, Ministry of Education, Shenyang Pharmaceutical University, Shenyang, China
| | - Jinhua Dong
- Key Laboratory of Structure-Based Drug Design and Discovery, Ministry of Education, Shenyang Pharmaceutical University, Shenyang, China
| | - Yongkui Jing
- Department of Medicine, The Tisch Cancer Institute, Mount Sinai School of Medicine, New York, New York, United States of America
- * E-mail:
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Shirley S, Micheau O. Targeting c-FLIP in cancer. Cancer Lett 2010; 332:141-50. [PMID: 21071136 DOI: 10.1016/j.canlet.2010.10.009] [Citation(s) in RCA: 104] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2010] [Revised: 09/29/2010] [Accepted: 10/11/2010] [Indexed: 12/15/2022]
Abstract
Cellular-FLICE inhibitory protein (c-FLIP) is a key anti-apoptotic regulator that inhibits cell death mediated by the death receptors Fas, DR4, DR5, and TNF-R1. Three splice variants of c-FLIP function at the DISC level by blocking the processing and activation of procaspase-8 and -10. Overexpression of c-FLIP has been identified in many different tumour types, and its downregulation in vitro has been shown to restore apoptosis mediated by CD95L and TRAIL. c-FLIP therefore represents a promising target for cancer therapy. This review focuses on the molecular mechanisms that control c-FLIP expression and current research into inhibitors of the protein. Increasing evidence supports the investigation of c-FLIP as a therapeutic target to restore an apoptotic response in cancer cells.
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Oh YT, Liu X, Yue P, Kang S, Chen J, Taunton J, Khuri FR, Sun SY. ERK/ribosomal S6 kinase (RSK) signaling positively regulates death receptor 5 expression through co-activation of CHOP and Elk1. J Biol Chem 2010; 285:41310-9. [PMID: 21044953 DOI: 10.1074/jbc.m110.153775] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Death receptor 5 (DR5) is a death domain-containing transmembrane receptor that triggers apoptosis upon binding to its ligand or when overexpressed. Its expression is induced by certain small molecule drugs, including celecoxib, through mechanisms that have not been fully elucidated. The current study has revealed a novel ERK/ribosomal S6 kinase (RSK)-dependent mechanism that regulates DR5 expression primarily using celecoxib as a DR5 inducer. Both C/EBP homologous protein (CHOP) and Elk1 are required for celecoxib-induced DR5 expression based on promoter deletion and mutation analysis and siRNA-mediated gene silencing results. Co-expression of both CHOP and Elk1 exhibited enhanced effects on increasing DR5 promoter activity and DR5 expression, indicating that CHOP and Elk1 co-operatively regulate DR5 expression. Because Elk1 is an ERK-regulated protein, we accordingly found that celecoxib increased the levels of phosphorylated ERK1/2, RSK2, and Elk1. Inhibition of either ERK signaling with a MEK inhibitor or ERK1/2 siRNA, or RSK2 signaling with an RSK2 inhibitor or RSK2 siRNA abrogated DR5 up-regulation by celecoxib as well as other agents. Moreover, these inhibitions suppressed celecoxib-induced CHOP up-regulation. Thus, ERK/RSK-dependent, CHOP and Elk1-mediated mechanisms are critical for DR5 induction. Additionally, celecoxib increased CHOP promoter activity in an ATF4-dependent manner, and siRNA-mediated blockade of ATF4 abrogated both CHOP induction and DR5 up-regulation, indicating that ATF4 is involved in celecoxib-induced CHOP and DR5 expression. Collectively, we conclude that small molecules such as celecoxib induce DR5 expression through activating ERK/RSK signaling and subsequent Elk1 activation and ATF4-dependent CHOP induction.
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Affiliation(s)
- You-Take Oh
- Department of Hematology and Medical Oncology, Emory University School of Medicine and Winship Cancer Institute, Atlanta, Georgia 30322, USA
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Kauh J, Fan S, Xia M, Yue P, Yang L, Khuri FR, Sun SY. c-FLIP degradation mediates sensitization of pancreatic cancer cells to TRAIL-induced apoptosis by the histone deacetylase inhibitor LBH589. PLoS One 2010; 5:e10376. [PMID: 20442774 PMCID: PMC2860986 DOI: 10.1371/journal.pone.0010376] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2010] [Accepted: 04/07/2010] [Indexed: 11/19/2022] Open
Abstract
Great efforts have been made to develop novel and efficacious therapeutics against pancreatic cancer to improve the treatment outcomes. Tumor-necrosis factor-related apoptosis-inducing ligand (TRAIL) is such a therapeutic cytokine with selective killing effect toward malignant cells. However, some human pancreatic cancers are intrinsically resistant to TRAIL-mediated apoptosis or therapy. In this study, we have shown that the histone deacetylase inhibitor LBH589 can synergize with TRAIL to augment apoptosis even in TRAIL-resistant cells. LBH589 decreased c-FLIP levels in every tested cell line and survivin levels in some of the tested cell lines. Enforced expression of ectopic c-FLIP, but not survivin, abolished the cooperative induction of apoptosis by the combination of LBH589 and TRAIL, indicating that c-FLIP downregulation plays a critical role in LBH589 sensitization of pancreatic cancer cells to TRAIL. Moreover, LBH589 decreased c-FLIP stability and the presence of the proteasome inhibitor MG132 prevented c-FLIP from reduction by LBH589. Correspondingly, we detected increased levels of ubiqutinated c-FLIP in LBH589-treated cells. These data thus indicate that LBH589 promotes ubiqutin/proteasome-mediated degradation of c-FLIP, leading to downregulation of c-FLIP. Collectively, LBH589 induces c-FLIP degradation and accordingly sensitizes pancreatic cancer cells to TRAIL-induced apoptosis, highlighting a novel therapeutic regimen against pancreatic cancer.
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Affiliation(s)
- John Kauh
- Department of Hematology and Medical Oncology, Emory University School of Medicine and Winship Cancer Institute, Atlanta, Georgia, United States of America
| | - Songqing Fan
- Department of Hematology and Medical Oncology, Emory University School of Medicine and Winship Cancer Institute, Atlanta, Georgia, United States of America
| | - Mingjing Xia
- Department of Hematology and Medical Oncology, Emory University School of Medicine and Winship Cancer Institute, Atlanta, Georgia, United States of America
| | - Ping Yue
- Department of Hematology and Medical Oncology, Emory University School of Medicine and Winship Cancer Institute, Atlanta, Georgia, United States of America
| | - Lily Yang
- Department of Surgery, Emory University School of Medicine and Winship Cancer Institute, Atlanta, Georgia, United States of America
| | - Fadlo R. Khuri
- Department of Hematology and Medical Oncology, Emory University School of Medicine and Winship Cancer Institute, Atlanta, Georgia, United States of America
| | - Shi-Yong Sun
- Department of Hematology and Medical Oncology, Emory University School of Medicine and Winship Cancer Institute, Atlanta, Georgia, United States of America
- * E-mail:
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Fecker LF, Stockfleth E, Braun FK, Rodust PM, Schwarz C, Köhler A, Leverkus M, Eberle J. Enhanced death ligand-induced apoptosis in cutaneous SCC cells by treatment with diclofenac/hyaluronic acid correlates with downregulation of c-FLIP. J Invest Dermatol 2010; 130:2098-109. [PMID: 20237495 DOI: 10.1038/jid.2010.40] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Actinic keratosis (AK) occurs on sun-exposed skin and may progress to invasive squamous cell carcinoma (SCC). As for its topical treatment, diclofenac/hyaluronic acid (HA) has been recently approved. The NSAID diclofenac is an inhibitor of COX-2; however, its mode of action in cutaneous epithelial cancer cells is largely unknown. Here, the effects of diclofenac/HA were investigated in relation to death ligand-mediated apoptosis (TNF-alpha, TRAIL, and CD95 activation). Whereas diclofenac/HA only moderately induced apoptosis by itself, it resulted in pronounced enhancement of death ligand-mediated apoptosis in sensitive SCC cell lines (3/4). Apoptosis was associated with activation of initiator caspases of the extrinsic pathway (caspase-8/caspase-10). Furthermore, death ligand and diclofenac/HA-mediated apoptosis were blocked by the same caspase inhibitors, indicating related pathways. The proapoptotic effects of diclofenac/HA appeared independent of the p53 pathway. Also, upregulation of death receptors appeared less important; however, strong downregulation of c-FLIP isoforms was seen after diclofenac/HA treatment. The crucial role of c-FLIP was proven through overexpression and knockdown experiments. Thus, induction of apoptosis appears to be highly characteristic of the mode of action of diclofenac/HA, and the therapeutic effect may be related to sensitization of neoplastic keratinocytes for death ligand-induced apoptosis.
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Affiliation(s)
- Lothar F Fecker
- Department of Dermatology and Allergy, HTCC Skin Cancer Center Charité, Charité-Universitätsmedizin Berlin, Berlin, Germany
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Llobet D, Eritja N, Yeramian A, Pallares J, Sorolla A, Domingo M, Santacana M, Gonzalez-Tallada F, Matias-Guiu X, Dolcet X. The multikinase inhibitor Sorafenib induces apoptosis and sensitises endometrial cancer cells to TRAIL by different mechanisms. Eur J Cancer 2010; 46:836-50. [DOI: 10.1016/j.ejca.2009.12.025] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2009] [Accepted: 12/16/2009] [Indexed: 01/07/2023]
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TRAIL receptor targeting therapies for non-small cell lung cancer: Current status and perspectives. Drug Resist Updat 2010; 13:2-15. [DOI: 10.1016/j.drup.2009.11.001] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2009] [Accepted: 11/25/2009] [Indexed: 12/17/2022]
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Chen S, Fu L, Raja SM, Yue P, Khuri FR, Sun SY. Dissecting the roles of DR4, DR5 and c-FLIP in the regulation of geranylgeranyltransferase I inhibition-mediated augmentation of TRAIL-induced apoptosis. Mol Cancer 2010; 9:23. [PMID: 20113484 PMCID: PMC2824632 DOI: 10.1186/1476-4598-9-23] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2009] [Accepted: 01/29/2010] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Geranylgeranyltransferase I (GGTase I) has emerged as a cancer therapeutic target. Accordingly, small molecules that inhibit GGTase I have been developed and exhibit encouraging anticancer activity in preclinical studies. However, their underlying anticancer mechanisms remain unclear. Here we have demonstrated a novel mechanism by which GGTase I inhibition modulates apoptosis. RESULTS The GGTase I inhibitor GGTI-298 induced apoptosis and augmented tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-induced apoptosis in human lung cancer cells. GGTI-298 induced DR4 and DR5 expression and reduced c-FLIP levels. Enforced c-FLIP expression or DR5 knockdown attenuated apoptosis induced by GGTI-298 and TRAIL combination. Surprisingly, DR4 knockdown sensitized cancer cells to GGTI298/TRAIL-induced apoptosis. The combination of GGTI-298 and TRAIL was more effective than each single agent in decreasing the levels of IkappaBalpha and p-Akt, implying that GGTI298/TRAIL activates NF-kappaB and inhibits Akt. Interestingly, knockdown of DR5, but not DR4, prevented GGTI298/TRAIL-induced IkappaBalpha and p-Akt reduction, suggesting that DR5 mediates reduction of IkappaBalpha and p-Akt induced by GGTI298/TRAIL. In contrast, DR4 knockdown further facilitated GGTI298/TRAIL-induced p-Akt reduction. CONCLUSIONS Both DR5 induction and c-FLIP downregulation contribute to GGTI-298-mediated augmentation of TRAIL-induced apoptosis. Moreover, DR4 appears to play an opposite role to DR5 in regulation of GGTI/TRAIL-induced apoptotic signaling.
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Affiliation(s)
- Shuzhen Chen
- Department of Hematology and Medical Oncology, Emory University School of Medicine and Winship Cancer Institute, Atlanta, Georgia, USA
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Proteasome inhibitors induce apoptosis in human lung cancer cells through a positive feedback mechanism and the subsequent Mcl-1 protein cleavage. Oncogene 2009; 28:3775-86. [PMID: 19684616 DOI: 10.1038/onc.2009.240] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Proteasome inhibitors (PIs) are promising new therapeutic agents for treating non-small cell lung carcinoma (NSCLC). To investigate the mechanisms of action of PIs, we analyzed the proapoptotic activities of PIs (MG132 or Bortezomib) in NSCLC cells. We found that both MG132 (>1 microM) and Bortezomib (>0.025 microM) induced a significant apoptosis in NCI-H1703, a PI-sensitive NSCLC cell line, through initially activating the intrinsic apoptosis pathway, leading to the activation of a positive feedback mechanism (PFM), which then conveyed apoptosis signaling from the intrinsic pathway to the extrinsic pathway with formation of a signaling loop for maximal caspase activation. Mcl-1 and Noxa were identified to be the major anti-apoptotic and proapoptotic proteins, respectively, in PI-induced apoptosis and mutually exclusive in protein stability. Although the Mcl-1 protein was upregulated by proteasome inhibition, it was also subjected to caspase 3-dependent cleavage governed by the PFM. Moreover, it was revealed that Mcl-1 protein cleavage contributed to PFM-governed apoptosis in following inter-related ways: reducing the anti-apoptotic Mcl-1; generating the truncated proapoptotic Mcl-1(S); and inducing a shift of balance between Mcl-1 and Noxa. It was further manifested that tumor necrosis factor-related apoptosis-inducing ligand boosted MG132's proapoptotic activity through strengthening the PFM in both NCI-H1703 and NCI-H358, a PI-resistant NSCLC cell line. Therefore, this study provides a basis for enhancing the efficacy of PIs in treating NSCLC.
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Giros A, Grzybowski M, Sohn VR, Pons E, Fernandez-Morales J, Xicola RM, Sethi P, Grzybowski J, Goel A, Boland CR, Gassull MA, Llor X. Regulation of colorectal cancer cell apoptosis by the n-3 polyunsaturated fatty acids Docosahexaenoic and Eicosapentaenoic. Cancer Prev Res (Phila) 2009; 2:732-42. [PMID: 19638488 DOI: 10.1158/1940-6207.capr-08-0197] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Several studies have suggested that the n-3 fatty acids Docosahexaenoic (DHA) and Eicosapentaenoic (EPA) have an important protective effect on colorectal cancer, and this could be at least partly due to their proapoptotic activity. It is unclear, however, how this phenomenon is triggered and what mechanisms are implicated. Here, we show that both DHA and EPA have an important proapoptotic effect on colorectal cancer cells with different molecular phenotypes but not in noncancerous cells. Apoptosis is caspase dependent, and both intrinsic and extrinsic pathways are implicated. The dimerization of Bax and Bak, the depolarization of the mitochondrial membrane, and the subsequent release of cytochrome c and Smac/Diablo to the cytosol evidence the activation of the intrinsic pathway. The implication of the extrinsic pathway is shown by the activation of caspase-8, along with the down-regulation of FLIP. The timing of caspase-8 activation, and the oligomerization of Bid with Bax, suggest a cross-talk with the intrinsic pathway. None of the death receptors that commonly initiate the extrinsic pathway: FAS, TNF-R1, and TRAIL-R2 are found to be responsible for triggering the apoptosis cascade induced by DHA and EPA. Neither PPARgamma nor cyclooxygenase-2, two likely candidates to regulate this process, play a significant role. Our findings suggest that the down-regulation of two key regulatory elements of the extrinsic and intrinsic pathways, FLIP and XIAP, respectively, is determinant in the induction of apoptosis by DHA and EPA. These fatty acids could potentially be useful adjuvant anticancer agents in combination with other chemotherapeutic elements.
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Affiliation(s)
- Anna Giros
- Department of Medicine, University of Illinois at Chicago, 840 South Wood Street (M/C 716), Chicago, IL 60612, USA
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Pawar P, Ma L, Byon CH, Liu H, Ahn EY, Jhala N, Arnoletti JP, McDonald JM, Chen Y. Molecular mechanisms of tamoxifen therapy for cholangiocarcinoma: role of calmodulin. Clin Cancer Res 2009; 15:1288-96. [PMID: 19228732 DOI: 10.1158/1078-0432.ccr-08-1150] [Citation(s) in RCA: 89] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
PURPOSE Cholangiocarcinoma is a fatal tumor with limited therapeutic options. We have reported that calmodulin antagonists tamoxifen and trifluoperazine induced apoptosis in cholangiocarcinoma cells. Here, we determined the effects of tamoxifen on tumorigenesis and the molecular mechanisms of tamoxifen-induced apoptosis. EXPERIMENTAL DESIGN Nude mice xenograft model of cholangiocarcinoma was used and tamoxifen was given i.p. and intratumorally. Cholangiocarcinoma cells were used to characterize molecular mechanisms of tamoxifen-induced apoptosis in vitro. RESULTS I.p. or intratumoral injection of tamoxifen decreased cholangiocarcinoma tumorigenesis by 40% to 80% in nude mice. In cells isolated from tumor xenografts, tamoxifen inhibited phosphorylation of AKT (pAKT) and cellular FLICE like inhibitory protein (c-FLIP). Immunohistochemical analysis further showed that pAKT was identified in all nontreated tumors but was absent in tamoxifen-treated tumors. In vitro, tamoxifen activated caspase-8 and caspase-10, and their respective inhibitors partially blocked tamoxifen-induced apoptosis. Overexpression of c-FLIP inhibited tamoxifen-induced apoptosis and enhanced tumorigenesis of cholangiocarcinoma cells in nude mice, whereas deletion of the calmodulin-binding domain on c-FLIP restored the sensitivity to tamoxifen and inhibited tumorigenesis. With two additional cholangiocarcinoma cell lines, we confirmed that the expression of FLIP is an important factor in mediating spontaneous and tamoxifen-induced apoptosis. CONCLUSIONS Thus, tamoxifen inhibits cholangiocarcinoma tumorigenesis in nude mice. Tamoxifen-induced apoptosis is partially dependent on caspases, inhibition of pAKT, and FLIP expression. Further, calmodulin-FLIP binding seems to be important in FLIP-mediated resistance to tamoxifen. Therefore, the present studies support the concept that tamoxifen may be used as a therapy for cholangiocarcinoma and possibly other malignancies in which the calmodulin targets AKT and c-FLIP play important roles in the tumor pathogenesis.
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Affiliation(s)
- Pritish Pawar
- Department of Pathology, University of Alabama at Birmingham, Birmingham, Alabama 35249-7331, USA
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Ou YC, Yang CR, Cheng CL, Li JR, Raung SL, Hung YY, Chen CJ. Indomethacin causes renal epithelial cell injury involving Mcl-1 down-regulation. Biochem Biophys Res Commun 2009; 380:531-6. [PMID: 19250643 DOI: 10.1016/j.bbrc.2009.01.094] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2009] [Accepted: 01/18/2009] [Indexed: 11/30/2022]
Abstract
Nonsteroidal anti-inflammatory drugs (NSAIDs) exert anti-tumor action in a variety of cancer cells. However, several treatment side effects such as gastrointestinal injury, cardiovascular toxicity, and acute renal failure limit their clinical use. We found that indomethacin caused renal epithelial cell injury independently of cyclooxygenase inhibition. Indomethacin treatment was associated with the disruption of mitochondrial transmembrane potential, release of cytochrome c, down-regulation of Bcl-2 and Mcl-1, upregulation of Bax, and elevation of caspases activity. Enhanced Mcl-1 but not Bcl-2 expression alleviated indomethacin-increased caspase-3 activity. Down-regulation of Akt-related and signal transducer and activator of transcription (STAT-3)-related pathways was found in indomethacin-treated cells. Pharmacological and genetic studies revealed a potential mechanistic link between Akt/Mcl-1 and STAT-3/Mcl-1 signaling pathways and indomethacin-induced cytotoxicity. Mcl-1 is a determinant molecule for the induction of epithelial cell injury caused by indomethacin. Therefore, the maintenance of Mcl-1 levels is important for prevention of renal epithelial cell injury and apoptosis.
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Affiliation(s)
- Yen-Chuan Ou
- Division of Urology, Taichung Veterans General Hospital, Taichung, Taiwan
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Lin Y, Liu X, Yue P, Benbrook DM, Berlin KD, Khuri FR, Sun SY. Involvement of c-FLIP and survivin down-regulation in flexible heteroarotinoid-induced apoptosis and enhancement of TRAIL-initiated apoptosis in lung cancer cells. Mol Cancer Ther 2008; 7:3556-65. [DOI: 10.1158/1535-7163.mct-08-0648] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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45
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Zhang H, Su L, Müller S, Tighiouart M, Xu Z, Zhang X, Shin HJC, Hunt J, Sun SY, Shin DM, Chen ZG. Restoration of caveolin-1 expression suppresses growth and metastasis of head and neck squamous cell carcinoma. Br J Cancer 2008; 99:1684-94. [PMID: 19002186 PMCID: PMC2584955 DOI: 10.1038/sj.bjc.6604735] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Caveolin-1 (Cav-1) plays an important role in modulating cellular signalling, but its role in metastasis is not well defined. A significant reduction in Cav-1 levels was detected in lymph node metastases as compared with primary tumour of head and neck squamous cell carcinoma (HNSCC) specimens (P<0.0001), confirming the downregulation of Cav-1 observed in a highly metastatic M4 cell lines derived from our orthotopic xenograft model. To investigate the function of Cav-1 in metastasis of HNSCC, we compared stable clones of M4 cells carrying human cav-1 cDNA (CavS) with cells expressing an empty vector (EV) in vitro and in the orthotopic xenograft model. Overexpression of Cav-1 suppressed growth of the CavS tumours compared with the EV tumours. The incidence of lung metastases was significantly lower in animals carrying CavS tumours than those with EV tumours (P=0.03). In vitro, CavS cells displayed reduced cell growth, invasion, and increased anoikis compared with EV cells. In CavS cells, Cav-1 formed complex with integrin beta1 and Src. Further application of integrin beta1 neutralising antibody or Src inhibitor PP2 to EV cells illustrated similar phenotypes as CavS cells, suggesting that Cav-1 may play an inhibitory role in tumorigenesis and lung metastasis through regulating integrin beta1- and Src-mediated cell-cell and cell-matrix interactions.
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Affiliation(s)
- H Zhang
- Department of Hematology and Medical Oncology, Winship Cancer Institute, Emory University School of Medicine, Atlanta, GA 30322, USA
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Kim S, Lee TJ, Leem J, Choi KS, Park JW, Kwon TK. Sanguinarine-induced apoptosis: generation of ROS, down-regulation of Bcl-2, c-FLIP, and synergy with TRAIL. J Cell Biochem 2008; 104:895-907. [PMID: 18189268 DOI: 10.1002/jcb.21672] [Citation(s) in RCA: 103] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Sanguinarine is a benzophenanthridine alkaloid derived from the root of Sanguinaria canadensis and other poppy-fumaria species, possessing potent antibacterial, antifungal, and anti-inflammatory activities. In this study, we investigated the underling mechanisms by which sanguinarine induce apoptosis in human breast cancer MDA-231 cells. Treatment of MDA-231 cells with sanguinarine induced remarkable apoptosis accompanying the generation of ROS. Consistently, sanguinarine-induced apoptosis was mediated by the increased reproductive cell death. Pretreatment with NAC or GSH attenuated sanguinarine-induced apoptosis, suggesting the involvement of ROS in this cell death. During sanguinarin-induced apoptosis, protein levels of pro-caspase-3, Bcl-2, cIAP2, XIAP, and c-FLIPs were reduced. Sanguinarine-mediated apoptosis was substantially blocked by ectopic expression of Bcl-2 and cFLIPs. Additionally, we found that sub-lethal doses of sanguinarine remarkably sensitized breast cancer cells to TRAIL-mediated apoptosis, but the cell death induced by sanguinarine and TRAIL in combination was not blocked by overexpression of Bcl-2 or Akt. Therefore, combinatory treatment of sanguinarine and TRAIL may overcome the resistance of breast cancer cells due to overexpression of Akt or Bcl-2.
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Affiliation(s)
- Shin Kim
- Department of Immunology and Chronic Disease Research Center and Institute for Medical Science, School of Medicine, Keimyung University, 194 DongSan-Dong Jung-Gu, Taegu 700-712, South Korea
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Day TW, Huang S, Safa AR. c-FLIP knockdown induces ligand-independent DR5-, FADD-, caspase-8-, and caspase-9-dependent apoptosis in breast cancer cells. Biochem Pharmacol 2008; 76:1694-704. [PMID: 18840411 DOI: 10.1016/j.bcp.2008.09.007] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2008] [Revised: 09/02/2008] [Accepted: 09/05/2008] [Indexed: 11/18/2022]
Abstract
Cellular-FLICE inhibitory protein (c-FLIP) is an inhibitor of apoptosis downstream of the death receptors Fas, DR4, and DR5, and is expressed as long (c-FLIP(L)) and short (c-FLIP(S)) splice forms. We found that the knockdown of c-FLIP using small interfering RNA (siRNA) triggered ligand-independent caspase-8- and -9-dependent spontaneous apoptosis and decreased the proliferation of MCF-7 breast cancer cells. Further analysis revealed that an apoptotic inhibitory complex (AIC) comprised of DR5, FADD, caspase-8, and c-FLIP(L) exists in MCF-7 cells, and the absence of c-FLIP(L) from this complex induces DR5- and FADD-mediated caspase-8 activation in the death inducing signaling complex (DISC). c-FLIP(S) was not detected in the AIC, and using splice form-specific siRNAs we showed that c-FLIP(L) but not c-FLIP(S) is required to prevent spontaneous death signaling in MCF-7 cells. These results clearly show that c-FLIP(L) prevents ligand-independent death signaling and provides direct support for studying c-FLIP as a relevant therapeutic target for breast cancers.
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Affiliation(s)
- Travis W Day
- Department of Pharmacology and Toxicology, Indiana University Simon Cancer Center, Indiana University School of Medicine, 1044 West Walnut Street R4-119, Indianapolis, IN 46202, USA
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Raja SM, Chen S, Yue P, Acker TM, Lefkove B, Arbiser JL, Khuri FR, Sun SY. The natural product honokiol preferentially inhibits cellular FLICE-inhibitory protein and augments death receptor-induced apoptosis. Mol Cancer Ther 2008; 7:2212-23. [PMID: 18645030 DOI: 10.1158/1535-7163.mct-07-2409] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Targeting death receptor-mediated apoptosis has emerged as an effective strategy for cancer therapy. However, certain types of cancer cells are intrinsically resistant to death receptor-mediated apoptosis. In an effort to identify agents that can sensitize cancer cells to death receptor-induced apoptosis, we have identified honokiol, a natural product with anticancer activity, as shown in various preclinical studies, as an effective sensitizer of death receptor-mediated apoptosis. Honokiol alone moderately inhibited the growth of human lung cancer cells; however, when combined with tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), greater effects on decreasing cell survival and inducing apoptosis than TRAIL alone were observed, indicating that honokiol cooperates with TRAIL to enhance apoptosis. This was also true to Fas-induced apoptosis when combined with Fas ligand or an agonistic anti-Fas antibody. Among several apoptosis-associated proteins tested, cellular FLICE-inhibitory protein (c-FLIP) was the only one that was rapidly down-regulated by honokiol in all of the tested cell lines. The down-regulation of c-FLIP by honokiol could be prevented by the proteasome inhibitor MG132. Moreover, honokiol increased c-FLIP ubiquitination. These results indicate that honokiol down-regulates c-FLIP by facilitating its degradation through a ubiquitin/proteasome-mediated mechanism. Enforced expression of ectopic c-FLIP abolished the ability of honokiol to enhance TRAIL-induced apoptosis. Several honokiol derivatives, which exhibited more potent effects on down-regulation of c-FLIP than honokiol, showed better efficacy than honokiol in inhibiting the growth and enhancing TRAIL-induced apoptosis as well. Collectively, we conclude that c-FLIP down-regulation is a key event for honokiol to modulate the death receptor-induced apoptosis.
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Affiliation(s)
- Shruti M Raja
- Department of Hematology and Medical Oncology, Winship Cancer Institute, Emory University School of Medicine, Atlanta, Georgia 30322, USA
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Wang X, Chen W, Zeng W, Bai L, Tesfaigzi Y, Belinsky SA, Lin Y. Akt-mediated eminent expression of c-FLIP and Mcl-1 confers acquired resistance to TRAIL-induced cytotoxicity to lung cancer cells. Mol Cancer Ther 2008; 7:1156-63. [PMID: 18483303 DOI: 10.1158/1535-7163.mct-07-2183] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is a potential anticancer agent due to its selectivity in killing transformed cells. However, TRAIL can also stimulate the proliferation and metastasis of TRAIL-resistant cancer cells. Thus, acquired TRAIL resistance during TRAIL therapy would shift the patient's treatment from beneficial to detrimental. In this study, we focused on the acquired TRAIL resistance mechanism and showed that the elevated expression of the antiapoptotic factor cellular FLICE-like inhibitory protein (c-FLIP) and the prosurvival Bcl-2 family member myeloid cell leukemia-1 (Mcl-1) underlie the main mechanism of this type of TRAIL resistance in lung cancer cells. Chronic exposure to TRAIL resulted in lung cancer cell resistance to TRAIL-induced cytotoxicity, and this resistance was associated with the increase in the cellular levels of c-FLIP(L) and Mcl-1(L). Overexpresssion of c-FLIP(L) suppressed recruitment of caspase-8 to the death-inducing signaling complex, whereas increased Mcl-1(L) expression blunted the mitochondrial apoptosis pathway. The elevation of c-FLIP(L) and Mcl-1(L) expression was due to Akt-mediated stabilization of these proteins in TRAIL-resistant cells. Importantly, suppressing c-FLIP(L) and Mcl-1(L) expression by RNA interference collectively alleviated acquired TRAIL resistance. Taken together, these results identify c-FLIP(L) and Mcl-1(L) as the major determinants of acquired TRAIL resistance and could be molecular targets for improving the therapeutic value of TRAIL against lung cancer.
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Affiliation(s)
- Xia Wang
- Molecular Biology and Lung Cancer Program, Lovelace Respiratory Research Institute, 2425 Ridgecrest Drive Southeast, Albuquerque, NM 87108, USA
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Baryawno N, Sveinbjörnsson B, Eksborg S, Orrego A, Segerström L, Oqvist CO, Holm S, Gustavsson B, Kågedal B, Kogner P, Johnsen JI. Tumor-growth-promoting cyclooxygenase-2 prostaglandin E2 pathway provides medulloblastoma therapeutic targets. Neuro Oncol 2008; 10:661-74. [PMID: 18715952 DOI: 10.1215/15228517-2008-035] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Prostaglandin E(2) (PGE(2)) has been shown to play important roles in several aspects of tumor development and progression. PGE(2) is synthesized from arachidonic acid by cyclooxygenases (COX) and prostaglandin E synthases (PGES) and mediates its biological activity through binding to the four prostanoid receptors EP(1) through EP(4). In this study, we show for the first time that medulloblastoma (MB), the most common malignant childhood brain tumor, expresses high levels of COX-2, microsomal prostaglandin E synthase-1, and EP(1) through EP(4) and secretes PGE(2). PGE(2) and the EP(2) receptor agonist butaprost stimulated MB cell proliferation. Treatment of MB cells with COX inhibitors suppressed PGE(2) production and induced caspase-dependent apoptosis. Similarly, specific COX-2 silencing by small interfering RNA inhibited MB cell growth. EP(1) and EP(3) receptor antagonists ONO-8713 and ONO-AE3-240, but not the EP(4) antagonists ONO-AE3-208 and AH 23848, inhibited tumor cell proliferation, indicating the significance of EP(1) and EP(3) but not EP(4) for MB growth. Administration of COX inhibitors at clinically achievable nontoxic concentrations significantly inhibited growth of established human MB xenografts. Apoptosis was increased, proliferation was reduced, and angiogenesis was inhibited in MBs treated with COX inhibitors. This study suggests that PGE(2) is important for MB growth and that therapies targeting the prostanoid metabolic pathway are potentially beneficial and should be tested in clinical settings for treatment of children with MB.
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Affiliation(s)
- Ninib Baryawno
- Childhood Cancer Research Unit, Dept. of Woman and Child Health, Karolinska Institutet, S-171-76, Stockholm, Sweden
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