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Ribas VT, Arruda-Carvalho M, Linden R, Chiarini LB. Early c-Jun N-terminal kinase-dependent phosphorylation of activating transcription factor-2 is associated with degeneration of retinal ganglion cells. Neuroscience 2011; 180:64-74. [PMID: 21300140 DOI: 10.1016/j.neuroscience.2011.01.059] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2010] [Revised: 01/24/2011] [Accepted: 01/26/2011] [Indexed: 12/12/2022]
Abstract
Neuron death due to deprivation of target-derived neurotrophic factors depends on protein synthesis regulated by transcription factor activity. We investigated the content and phosphorylation of activating transcription factor 2 (ATF-2) in axon-damaged retinal ganglion cells of neonatal rats. In the retina of neonatal rats, the ATF-2 protein is predominantly located in the nucleus of the ganglion cells. A gradual loss of the immunoreactivity for ATF-2 occurred after explantation. ATF-2 is phosphorylated early after explantation, with a peak within 3 hours, preceding the peak of cell death that occurs at 18 hours. Both the phosphorylation of ATF-2 and ganglion cell death were blocked by treatment with an inhibitor of c-Jun N-terminal kinase (JNK), whereas an inhibitor of p38 reduced only slightly the rate of ganglion cell death with no effect upon phosphorylation of ATF-2. Inhibitors of phosphatidyl inositol 3 kinase (PI-3K), protein kinase C (PKC) or extracellular regulated kinase (ERK) had no effect. Finally, the inhibitor of JNK blocked the upregulation of both c-Jun and Hrk in the GCL after retinal explantation. The data show that phosphorylation of ATF-2 by JNK is associated with retinal ganglion cell death after axon damage.
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Affiliation(s)
- V T Ribas
- Instituto de Biofísica Carlos Chagas Filho, UFRJ, Rio de Janeiro, Brasil
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102
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c-JUN promotes BCR-ABL-induced lymphoid leukemia by inhibiting methylation of the 5' region of Cdk6. Blood 2011; 117:4065-75. [PMID: 21300982 DOI: 10.1182/blood-2010-07-299644] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The transcription factor c-JUN and its upstream kinase JNK1 have been implicated in BCR-ABL-induced leukemogenesis. JNK1 has been shown to regulate BCL2 expression, thereby altering leukemogenesis, but the impact of c-JUN remained unclear. In this study, we show that JNK1 and c-JUN promote leukemogenesis via separate pathways, because lack of c-JUN impairs proliferation of p185(BCR-ABL)-transformed cells without affecting their viability. The decreased proliferation of c-Jun(Δ/Δ) cells is associated with the loss of cyclin-dependent kinase 6 (CDK6) expression. In c-Jun(Δ/Δ) cells, CDK6 expression becomes down-regulated upon BCR-ABL-induced transformation, which correlates with CpG island methylation within the 5' region of Cdk6. We verified the impact of Cdk6 deficiency using Cdk6(-/-) mice that developed BCR-ABL-induced B-lymphoid leukemia with significantly increased latency and an attenuated disease phenotype. In addition, we show that reexpression of CDK6 in BCR-ABL-transformed c-Jun(Δ/Δ) cells reconstitutes proliferation and tumor formation in Nu/Nu mice. In summary, our study reveals a novel function for the activating protein 1 (AP-1) transcription factor c-JUN in leukemogenesis by antagonizing promoter methylation. Moreover, we identify CDK6 as relevant and critical target of AP-1-regulated DNA methylation on BCR-ABL-induced transformation, thereby accelerating leukemogenesis.
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103
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Kurata O, Iwasaki T, Matsuyama T, Nakayasu C, Wada S, Hatai K. Lymphocytes with T-cell-like properties express the Fas ligand in the Japanese flounder Paralichthys olivaceus. FISH & SHELLFISH IMMUNOLOGY 2011; 30:509-514. [PMID: 21134463 DOI: 10.1016/j.fsi.2010.11.030] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2010] [Revised: 11/13/2010] [Accepted: 11/28/2010] [Indexed: 05/30/2023]
Abstract
In this study, we aimed to identify the leukocyte population that expresses Fas ligand (FasL) in the Japanese flounder (Paralichthys olivaceus). The transcriptional activity of FasL was examined for the first time in the fish leukocytes. Transcription of the FasL gene in flounder leukocytes was significantly increased by phytohemagglutinin (PHA) treatment. All the leukocyte populations we tested possessed binding activity for PHA, but this was especially high in the lymphocyte population. However, the lymphocytes consisted of two subsets showing heterogeneity with respect to PHA binding, with the high-binding subset being surface IgM-negative. We also found that only the lymphocyte population showed a significant increase in the expression of the FasL gene after stimulation with PHA. In addition, only the lymphocyte subset showing high binding to PHA showed conspicuous expression of the FasL gene. This subset also had a CD3γ/δ+, CD8α+ and IgM heavy-chain (-) phenotype. These results suggested that lymphocytes with T-cell-like properties are FasL-expressing cells in the Japanese flounder.
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Affiliation(s)
- Osamu Kurata
- Laboratory of Fish Diseases, Department of Veterinary Science, Nippon Veterinary and Life Science University, 1-7-1 Kyonan-cho, Musashino, Tokyo 180-8602, Japan.
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104
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Latorre A, Caniceiro B, Wysocki H, Haraguchi M, Gardner D, Górniak S. Selenium reverses Pteridium aquilinum-induced immunotoxic effects. Food Chem Toxicol 2011; 49:464-70. [DOI: 10.1016/j.fct.2010.11.026] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2010] [Revised: 11/03/2010] [Accepted: 11/20/2010] [Indexed: 12/27/2022]
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105
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Chen HM, Liu CM, Yang H, Chou HY, Chiang CP, Kuo MYP. 5-aminolevulinic acid induce apoptosis via NF-κB/JNK pathway in human oral cancer Ca9-22 cells. J Oral Pathol Med 2010; 40:483-9. [PMID: 21138480 DOI: 10.1111/j.1600-0714.2010.00973.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
BACKGROUND 5-aminolevulinic acid-based photodynamic therapy (5-ALA-PDT) is being used to treat oral pre-cancerous and cancerous lesions with some encouraging clinical outcomes. However, the exact mechanisms behind the photodynamic treatment are still not fully elucidated. METHOD Flow cytometry, TdT-mediated dUTP nick end labeling assay and Western blot analysis were used to investigate the effects of 5-ALA-PDT on human oral cancer Ca9-22 cells. RESULTS We found that 5-ALA-PDT induces apoptosis in Ca9-22 cells. Western blotting showed that 5-ALA-PDT activates both the caspase-8 and caspase-9 pathways, which differed from previous studies conducted in other cell types. Activation of JNK was evident as early as 30 min. The caspases activation was inhibited by JNK inhibitor SP600125. Treatment with NF-κB inhibitor Bay 11-7082 (Bay) completely abrogated ALA-PDT-induced JNK activation. In addition, Bay and SP600125 almost completely abolished ALA-PDT-induced apoptosis. CONCLUSION These results demonstrate significant involvement of caspase-8 and -9 and their upstream NF-κB-JNK pathways in ALA-PDT-induced apoptosis. Future studies on how NF-κB and JNK activity regulate ALA-PDT response should provide a better strategy for the treatment of oral cancer.
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Affiliation(s)
- Hsin-Ming Chen
- School of Dentistry, College of Medicine, National Taiwan University, Taipei, Taiwan
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106
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Saekoo J, Graidist P, Leeanansaksiri W, Dechsukum C, Itharat A. Dioscorealide B from the Traditional Thai Medicine Hua-Khao-Yen Induces Apoptosis in MCF-7 Human Breast Cancer Cells via Modulation of Bax, Bak and Bcl-2 Protein Expression. Nat Prod Commun 2010. [DOI: 10.1177/1934578x1000501217] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Dioscorealide B is a pharmacologically active compound from the rhizome of the Thai medicinal plant Dioscorea membranacea. Here, we demonstrated that in vitro treatment of dioscorealide B resulted in a cytotoxic effect on MCF-7 human breast cancer cells (IC50 = 2.82 μM). To determine whether this compound induces apoptosis in MCF-7, the Annexin V assay was performed. The data showed that the number of apoptotic cells were increased 7–12 folds over that of the control cells after treatment with various concentrations of dioscorealide B (3, 6 and 12 μM) for 24 hours. Dioscorealide B-induced apoptosis was associated with modulation of the multidomain Bcl-2 family members Bax, Bak and Bcl-2. After treatment with 3 μM dioscorealide B, acceleration of the level of proapoptotic proteins Bax and Bak were observed at 6 hours and 12 hours, respectively, while the decrease in the expression of antiapoptotic protein Bcl-2 was observed 3 hours after the treatment. These effects of dioscorealide B might result in the activation of caspase-8, -9 and -7, which lead to apoptosis in MCF-7 cells. Taken together, the results of this study provide evidence that dioscorealide B possesses an antitumor property against human breast cancer cells and thus provide the molecular basis for the further development of dioscorealide B as a novel chemotherapeutic agent for breast cancer treatment.
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Affiliation(s)
- Jiraporn Saekoo
- Department of Biomedical Sciences, Faculty of Medicine, Prince of Songkla University, Hadyai, Songkla, 90110, Thailand
| | - Potchanapond Graidist
- Department of Biomedical Sciences, Faculty of Medicine, Prince of Songkla University, Hadyai, Songkla, 90110, Thailand
| | - Wilairat Leeanansaksiri
- School of Microbiology, Suranaree University of Technology, Muang, Nakornrajchaseema, 30000, Thailand
- Stem Cell Therapy and Transplantation Research Group Institute of Science, Suranaree University of Technology, Muang, Nakornrajchaseema, 30000, Thailand
| | - Chavaboon Dechsukum
- School of Pathology, Suranaree University of Technology, Muang, Nakornrajchaseema, 30000, Thailand
- Gene Therapy and Application Research Group, Institute of Medicine, Suranaree University of Technology, Muang, Nakornrajchaseema, 30000, Thailand
| | - Arunporn Itharat
- Department of Applied Thai Traditional Medicine, Faculty of Medicine, Thammasat University, Klongluang, Pathumtanee, 12120, Thailand
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Role of sulfurous mineral water and sodium hydrosulfide as potent inhibitors of fibrosis in the heart of diabetic rats. Arch Biochem Biophys 2010; 506:48-57. [PMID: 20965145 DOI: 10.1016/j.abb.2010.10.014] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2010] [Revised: 10/10/2010] [Accepted: 10/14/2010] [Indexed: 02/05/2023]
Abstract
This study examined the downstream signaling whereby hyperglycemia may lead to myocardial fibrosis and apoptosis in the left ventricle of diabetic rats. The effects of sulfurous mineral water or sodium hydrosulfide (NaHS) as possible modulators were also examined. Sulfurous mineral water (as drinking water) and NaHS (14μmol/kg/day, IP) were administered for 7 week to rats with streptozotocin (STZ)-induced diabetes. Hyperglycemia, overproduction of glycated hemoglobin (HbA1C) and serum decline in insulin, C-peptide and insulin like growth factor-I (IGF-I) were observed in diabetic rats. Up-regulation of gene expressions of nuclear factor (NF-κB), profibrogenic growth factor such as transforming growth factor-β1 (TGF-β1), matrix metalloproteniase-2 (MMP-2), procollagen-1 and Fas ligand (Fas-L) were observed in the left ventricle of diabetic rats. A linear positive correlation between TGF-β1 and MMP-2 was also detected in diabetic group. An increase in hydroxyproline level and a disturbance in oxidative balance were detected in heart of diabetic rats. Sulfurous mineral water and NaHS treatment possibly, by improving cardiac GSH level, counteracted the enhanced expression of NF-κB, the profibrogenic and apoptotic parameters. Histopathological examination was in accordance with the biochemical and molecular findings of this study. We suggest a novel therapeutic approach of sulfurous mineral water and exogenous supplementation of H(2)S in diabetic cardiomyopathy.
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108
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Cheung HH, Beug ST, St Jean M, Brewster A, Kelly NL, Wang S, Korneluk RG. Smac mimetic compounds potentiate interleukin-1beta-mediated cell death. J Biol Chem 2010; 285:40612-23. [PMID: 20956527 DOI: 10.1074/jbc.m110.183616] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Smac mimetic compounds (SMCs) potentiate TNFα-mediated cancer cell death by targeting the inhibitor of apoptosis (IAP) proteins. In addition to TNFα, the tumor microenvironment is exposed to a number of pro-inflammatory cytokines, including IL-1β. Here, we investigated the potential impact of IL-1β on SMC-mediated death of cancer cells. Synergy was seen in a subset of a diverse panel of 21 cancer cell lines to the combination of SMC and IL-1β treatment, which required IL-1β-induced activation of the NF-κB pathway. Elevated NF-κB activity resulted in the production of TNFα, which led to apoptosis dependent on caspase-8 and RIP1. In addition, concurrent silencing of cIAP1, cIAP2, and X-linked IAP by siRNA was most effective for triggering IL-1β-mediated cell death. Importantly, SMC-resistant cells that produced TNFα in response to IL-1β treatment were converted to an SMC-sensitive phenotype by c-FLIP knockdown. Reciprocally, ectopic expression of c-FLIP blocked cell death caused by combined SMC and IL-1β treatment in sensitive cancer cells. Together, our study indicates that a positive feed-forward loop by pro-inflammatory cytokines can be exploited by SMCs to induce apoptosis in cancer cells.
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Affiliation(s)
- Herman H Cheung
- Apoptosis Research Centre, Children's Hospital of Eastern Ontario Research Institute, Ottawa, Ontario K1H 8L1, Canada
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109
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Duan SG, Cheng L, Li DJ, Zhu J, Xiong Y, Li XW, Wang SG. The role of MAPK-ERK pathway in 67-kDa laminin receptor-induced FasL expression in human cholangiocarcinoma cells. Dig Dis Sci 2010; 55:2844-52. [PMID: 20101459 DOI: 10.1007/s10620-009-1121-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/28/2009] [Accepted: 12/28/2009] [Indexed: 12/17/2022]
Abstract
BACKGROUND AND AIMS Cancer cells are thought to possess immune evasion properties due to FasL overexpression in many types of human tumors. In the present study, we set out to investigate the role of MAPK-ERK pathway in 67-kDa laminin receptor induced FasL expression and FasL-mediated apoptosis in human cholangiocarcinoma cells. METHODS The expression of FasL and its promoter activity in cultured cholangiocarcinoma cells were examined after treatment with laminin or transfection with plasmids containing siRNA targeted to 67-kDa laminin receptor. The effects of MAPK-ERK cascade inhibitor and c-Myc inhibition by siRNA on 67-kDa laminin receptor-induced FasL expression were determined. Apoptosis assay was performed to analyze the apoptosis of lymphocytes cocultured with cholangiocarcinoma cells treated with or without MAPK-ERK cascade inhibitor. RESULTS Our results revealed that the specific MAPK-ERK cascade inhibitor, PD98059, significantly attenuated phosphorylation of c-Myc on Ser-62 and FasL upregulation in QBC-939 cells and these cells showed decreased cytotoxicity against Fas-sensitive Jurkat T cells. A luciferase reporter assay revealed that FasL promoter activity was significantly reduced in cells treated with PD98059 or transfected with c-Myc siRNA. CONCLUSIONS Based on these results, we conclude that 67LR induces FasL expression and cytotoxicity against Fas-sensitive Jurkat T cells in human cholangiocarcinoma cells through the phosphorylation of c-Myc on Ser-62 and the subsequent activation of the FasL promoter through the ERK pathway.
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Affiliation(s)
- Shi-Gang Duan
- Hepatobiliary Surgery Hospital and Institute, Southwest Hospital, Third Military Medical University, 400038, Chongqing, China
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110
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Tsuchiya Y, Asano T, Nakayama K, Kato T, Karin M, Kamata H. Nuclear IKKbeta is an adaptor protein for IkappaBalpha ubiquitination and degradation in UV-induced NF-kappaB activation. Mol Cell 2010; 39:570-82. [PMID: 20797629 DOI: 10.1016/j.molcel.2010.07.030] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2009] [Revised: 02/12/2010] [Accepted: 06/14/2010] [Indexed: 11/15/2022]
Abstract
Proinflammatory cytokines activate NF-kappaB using the IkappaB kinase (IKK) complex that phosphorylates inhibitory proteins (IkappaBs) at N-terminal sites resulting in their ubiquitination and degradation in the cytoplasm. Although ultraviolet (UV) irradiation does not lead to IKK activity, it activates NF-kappaB by an unknown mechanism through IkappaBalpha degradation without N-terminal phosphorylation. Here, we describe an adaptor function of nuclear IKKbeta in UV-induced IkappaBalpha degradation. UV irradiation induces the nuclear translocation of IkappaBalpha and association with IKKbeta, which constitutively interacts with beta-TrCP through heterogeneous ribonucleoprotein-U (hnRNP-U) leading to IkappaBalpha ubiquitination and degradation. Furthermore, casein kinase 2 (CK2) and p38 associate with IKKbeta and promote IkappaBalpha degradation by phosphorylation at C-terminal sites. Thus, nuclear IKKbeta acts as an adaptor protein for IkappaBalpha degradation in UV-induced NF-kappaB activation. NF-kappaB activated by the nuclear IKKbeta adaptor protein suppresses anti-apoptotic gene expression and promotes UV-induced cell death.
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Affiliation(s)
- Yoshihiro Tsuchiya
- Laboratory of Biomedical Chemistry, Department of Molecular Medical Science, Graduate School of Biomedical Science, Hiroshima University, Kasumi 1-2-3, Minami-ku, Hiroshima 734-8553, Japan
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111
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Luqman S, Pezzuto JM. NFkappaB: a promising target for natural products in cancer chemoprevention. Phytother Res 2010; 24:949-63. [PMID: 20577970 DOI: 10.1002/ptr.3171] [Citation(s) in RCA: 150] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The transcription factor nuclear factor kappa B (NFkappaB) is found in nearly all animal cell types. It is involved in cellular responses to stimuli such as stress, cytokines, free radicals, ultraviolet irradiation, oxidized LDL and microbial antigens, and has been shown to regulate the expression of a number of genes including bcl-2, bcl-xl, cIAP, suvivin, TRAF, COX-2, MMP-9, iNOS and cell cycle-regulatory components. Many carcinogens, inflammatory agents and tumor promoters have been shown to activate NFkappaB, and resulting tumors demonstrate misregulated NFkappaB. Incorrect regulation of NFkappaB has been linked to inflammatory and autoimmune diseases, septic shock, viral infection and improper immune development. Aberrant regulation of NFkappaB is involved in cancer development and progression as well as in drug resistance. Inhibitors of NFkappaB mediate effects potentially leading to antitumor responses or greater sensitivity to the action of antitumor agents. Tools have been developed for the rapid assessment of NFkappaB activity, so in concert with a better understanding of NFkappaB activation mechanisms, many agents capable of suppressing NFkappaB activation have been identified. The present article focuses on the functions of NFkappaB, its role in human cancer and the therapeutic potential and benefit of targeting NFkappaB by natural products in cancer chemoprevention.
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Affiliation(s)
- Suaib Luqman
- College of Pharmacy, University of Hawaii, Hilo 96720, USA
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112
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Abstract
The vitamin A metabolite all-trans-retinoic acid (RA) regulates multiple biological processes by virtue of its ability to regulate gene expression. It thus plays critical roles in embryonic development and is involved in regulating growth, remodeling, and metabolic responses in adult tissues. RA can also suppress carcinoma cell growth and is currently used in treatment of some cancers. Growth inhibition by RA may be exerted by induction of differentiation, cell cycle arrest, or apoptosis, or by a combination of these activities. Paradoxically, in the context of some cells, RA not only fails to inhibit growth but, instead, enhances proliferation and survival. This review focuses on the involvement of RA in regulating apoptotic responses. It includes brief overviews of transcriptional signaling by RA and of apoptotic pathways, and then addresses available information on the mechanisms by which RA induces apoptosis or, conversely, inhibits cell death and enhances survival.
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Affiliation(s)
- Noa Noy
- Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, Ohio 44106-4965, USA.
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113
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Danthi P, Pruijssers AJ, Berger AK, Holm GH, Zinkel SS, Dermody TS. Bid regulates the pathogenesis of neurotropic reovirus. PLoS Pathog 2010; 6:e1000980. [PMID: 20617182 PMCID: PMC2895667 DOI: 10.1371/journal.ppat.1000980] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2009] [Accepted: 06/02/2010] [Indexed: 11/19/2022] Open
Abstract
Reovirus infection leads to apoptosis in both cultured cells and the murine central nervous system (CNS). NF-kappaB-driven transcription of proapoptotic cellular genes is required for the effector phase of the apoptotic response. Although both extrinsic death-receptor signaling pathways and intrinsic pathways involving mitochondrial injury are implicated in reovirus-induced apoptosis, mechanisms by which either of these pathways are activated and their relationship to NF-kappaB signaling following reovirus infection are unknown. The proapoptotic Bcl-2 family member, Bid, is activated by proteolytic cleavage following reovirus infection. To understand how reovirus integrates host signaling circuits to induce apoptosis, we examined proapoptotic signaling following infection of Bid-deficient cells. Although reovirus growth was not affected by the absence of Bid, cells lacking Bid failed to undergo apoptosis. Furthermore, we found that NF-kappaB activation is required for Bid cleavage and subsequent proapoptotic signaling. To examine the functional significance of Bid-dependent apoptosis in reovirus disease, we monitored fatal encephalitis caused by reovirus in the presence and absence of Bid. Survival of Bid-deficient mice was significantly enhanced in comparison to wild-type mice following either peroral or intracranial inoculation of reovirus. Decreased reovirus virulence in Bid-null mice was accompanied by a reduction in viral yield. These findings define a role for NF-kappaB-dependent cleavage of Bid in the cell death program initiated by viral infection and link Bid to viral virulence.
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Affiliation(s)
- Pranav Danthi
- Department of Biology, Indiana University, Bloomington, Indiana, United States of America
| | - Andrea J. Pruijssers
- Department of Pediatrics, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America
- Elizabeth B. Lamb Center for Pediatric Research, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America
| | - Angela K. Berger
- Department of Biology, Indiana University, Bloomington, Indiana, United States of America
| | - Geoffrey H. Holm
- Department of Pediatrics, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America
- Elizabeth B. Lamb Center for Pediatric Research, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America
| | - Sandra S. Zinkel
- Department of Medicine, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America
| | - Terence S. Dermody
- Department of Pediatrics, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America
- Elizabeth B. Lamb Center for Pediatric Research, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America
- Department of Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America
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114
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Price M, Badaut J, Thevenet J, Hirt L. Activation of c-Jun in the nuclei of neurons of the CA-1 in thrombin preconditioning occurs via PAR-1. J Neurosci Res 2010; 88:1338-47. [PMID: 19937805 DOI: 10.1002/jnr.22299] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Recently it has been shown that the c-Jun N-terminal kinase (JNK) plays a role in thrombin preconditioning (TPC) in vivo and in vitro. To investigate further the pathways involved in TPC, we performed an immunohistochemical study in hippocampal slice cultures. Here we show that the major target of JNK, the AP-1 transcription factor c-Jun, is activated by phosphorylation in the nuclei of neurons of the CA1 region by using phospho-specific antibodies against the two JNK phosphorylation sites. The activation is early and transient, peaking at 90 min and not present by 3 hr after low-dose thrombin administration. Treatment of cultures with a synthetic thrombin receptor agonist results in the same c-Jun activation profile and protection against subsequent OGD, both of which are prevented by specific JNK inhibitors, showing that thrombin signals through PAR-1 to JNK. By using an antibody against the Ser 73 phosphorylation site of c-Jun, we identify possible additional TPC substrates.
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Affiliation(s)
- Melanie Price
- Neurology Service, Centre Hospitalier Universitaire Vaudois, Lausanne, Switzerland
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115
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Yang J, Li JH, Wang J, Zhang CY. Molecular modeling of BAD complex resided in a mitochondrion integrating glycolysis and apoptosis. J Theor Biol 2010; 266:231-41. [PMID: 20540951 DOI: 10.1016/j.jtbi.2010.06.009] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2010] [Revised: 04/27/2010] [Accepted: 06/04/2010] [Indexed: 11/15/2022]
Abstract
BAD (Bcl-2 antagonist of cell death) and GK (glucokinase) reside in a mitochondrial complex together with PKA and PP1 catalytic units (PKAc and PP1c) and WAVE-1 that integrates glycolysis and apoptosis. Our research results reveal that BAD is phosphorylated and inactivated on Ser 75 in a BAD-Bcl-xL complex by PKA (targeted to mitochondria through association with WAVE1), resulting in the dissociation of BAD and its binding to GK. Moreover, GK can interact with PP1c and also distinguish WAVE1. On the other hand, BAD is dephosphorylated and activated on Ser75 by PP1c, leading to the separation of PKAc and its binding to the regulatory (R) subunit of PKA which by the dimerization domain of its R subunit connects with WAVE1 linked with GK of the complex. This may be the reason of the complex existing in liver mitochondria, regardless of phosphorylated and dephosphorylated BAD. Additionally, GK like PKA may also prevent Bcl-xL from rebinding to BAD by phosphorylating BAD at Ser 118. The BAD complex model reveals that BAD and GK play key roles because of BAD as a substrate for the PKA-PP1 pair and by BH3 domain directly interacting with GK. This is helpful for our development and research of the molecular mechanism of BAD integrating glycolysis and apoptosis.
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Affiliation(s)
- Jie Yang
- State Key Laboratory of Pharmaceutical Biotechnology, College of Life Sciences, Nanjing University, Nanjing 210093, PR China.
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116
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Abstract
Hox genes, a highly conserved subgroup of the homeobox superfamily, have crucial roles in development, regulating numerous processes including apoptosis, receptor signalling, differentiation, motility and angiogenesis. Aberrations in Hox gene expression have been reported in abnormal development and malignancy, indicating that altered expression of Hox genes could be important for both oncogenesis and tumour suppression, depending on context. Therefore, Hox gene expression could be important in diagnosis and therapy.
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Affiliation(s)
- Nilay Shah
- Nilay Shah and Saraswati Sukumar are at the Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, Baltimore, MD 21231, USA
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117
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Himer L, Csóka B, Selmeczy Z, Koscsó B, Pócza T, Pacher P, Németh ZH, Deitch EA, Vizi ES, Cronstein BN, Haskó G. Adenosine A2A receptor activation protects CD4+ T lymphocytes against activation-induced cell death. FASEB J 2010; 24:2631-40. [PMID: 20371613 DOI: 10.1096/fj.10-155192] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Activation-induced cell death (AICD) is initiated by T-cell receptor (TCR) restimulation of already activated and expanded peripheral T cells and is mediated through Fas/Fas ligand (FasL) interactions. Adenosine is a purine nucleoside signaling molecule, and its immunomodulatory effects are mediated by 4 G-protein-coupled receptors: A(1), A(2A), A(2B), and A(3). In this study, we investigated the role of A(2A) receptors in regulating CD4(+) T lymphocyte AICD. Our results showed that the selective A(2A) receptor agonist CGS21680 (EC(50)=15.2-32.6 nM) rescued mouse CD4(+) hybridomas and human Jurkat cells from AICD and that this effect was reversed by the selective A(2A) receptor antagonist ZM241385 (EC(50)=2.3 nM). CGS21680 decreased phosphatidylserine exposure on the membrane, as well as the cleavage of caspase-3, caspase-8 and poly(ADP-ribose) polymerase indicating that A(2A) receptor stimulation blocks the extrinsic apoptotic pathway. In addition, CGS21680 attenuated both Fas and FasL mRNA expression. This decrease in FasL expression was associated with decreased activation of the transcription factor systems NF-kappaB, NF-ATp, early growth response (Egr)-1, and Egr-3. The antiapoptotic effect of A(2A) receptor stimulation was mediated by protein kinase A. Together, these results demonstrate that A(2A) receptor activation suppresses the AICD of peripheral T cells.
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Affiliation(s)
- Leonóra Himer
- Department of Pharmacology, Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary
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118
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Mahmood Z, Shukla Y. Death receptors: Targets for cancer therapy. Exp Cell Res 2010; 316:887-99. [DOI: 10.1016/j.yexcr.2009.12.011] [Citation(s) in RCA: 135] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2009] [Revised: 12/08/2009] [Accepted: 12/13/2009] [Indexed: 12/24/2022]
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119
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Glucose deprivation induces an atypical form of apoptosis mediated by caspase-8 in Bax-, Bak-deficient cells. Cell Death Differ 2010; 17:1335-44. [PMID: 20203689 DOI: 10.1038/cdd.2010.21] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Apoptosis induced by most stimuli proceeds through the mitochondrial pathway. One such stimulus is nutrient deprivation. In this study we studied death induced by glucose deprivation in cells deficient in Bax and Bak. These cells cannot undergo mitochondrial outer membrane permeabilization (MOMP) during apoptosis, but they undergo necrosis when treated with MOMP-dependent apoptotic stimuli. We find in these cells that glucose deprivation, rather than inducing necrosis, triggered apoptosis. Cell death required caspase activation as inhibition of caspases with peptidic inhibitors prevented death. Glucose deprivation-induced death displayed many hallmarks of apoptosis, such as caspase cleavage and activity, phosphatidyl-serine exposure and cleavage of caspase substrates. Neither overexpression of Bcl-xL nor knockdown of caspase-9 prevented death. However, transient or stable knockdown of caspase-8 or overexpression of CrmA inhibited apoptosis. Cell death was not inhibited by preventing death receptor-ligand interactions, by overexpression of c-FLIP or by knockdown of RIPK1. Glucose deprivation induced apoptosis in the human tumor cell line HeLa, which was prevented by knockdown of caspase-8. Thus, we have found that glucose deprivation can induce a death receptor-independent, caspase-8-driven apoptosis, which is engaged to kill cells that cannot undergo MOMP.
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120
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Chen KC, Liu WH, Chang LS. Taiwan cobra phospholipase A2-elicited JNK activation is responsible for autocrine fas-mediated cell death and modulating Bcl-2 and Bax protein expression in human leukemia K562 cells. J Cell Biochem 2010; 109:245-54. [PMID: 19937732 DOI: 10.1002/jcb.22404] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Phospholipase A(2) (PLA(2)) from Naja naja atra venom induced apoptotic death of human leukemia K562 cells. Degradation of procaspases, production of tBid, loss of mitochondrial membrane potential, Bcl-2 degradation, mitochondrial translocation of Bax, and cytochrome c release were observed in PLA(2)-treated cells. Moreover, PLA(2) treatment increased Fas and FasL protein expression. Upon exposure to PLA(2), activation of p38 MAPK (mitogen-activated protein kinase) and JNK (c-Jun NH(2)-terminal kinase) was found in K562 cells. SB202190 (p38 MAPK inhibitor) pretreatment enhanced cytotoxic effect of PLA(2) and led to prolonged JNK activation, but failed to affect PLA(2)-induced upregulation of Fas and FasL protein expression. Sustained JNK activation aggravated caspase8/mitochondria-dependent death pathway, downregulated Bcl-2 expression and increased mitochondrial translocation of Bax. SP600125 (JNK inhibitor) abolished the cytotoxic effect of PLA(2) and PLA(2)-induced autocrine Fas death pathway. Transfection ASK1 siRNA and overexpression of dominant negative p38alpha MAPK proved that ASK1 pathway was responsible for PLA(2)-induced p38 MAPK and JNK activation and p38alpha MAPK activation suppressed dynamically persistent JNK activation. Downregulation of FADD abolished PLA(2)-induced procaspase-8 degradation and rescued viability of PLA(2)-treated cells. Taken together, our results indicate that JNK-mediated autocrine Fas/FasL apoptotic mechanism and modulation of Bcl-2 family proteins are involved in PLA(2)-induced death of K562 cells.
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Affiliation(s)
- Ku-Chung Chen
- Institute of Biomedical Sciences, National Sun Yat-Sen University-Kaohsiung Medical University Joint Research Center, National Sun Yat-Sen University, Kaohsiung 804, Taiwan
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121
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NF-kappaB and cancer: how intimate is this relationship. Mol Cell Biochem 2010; 336:25-37. [PMID: 19823771 PMCID: PMC3148942 DOI: 10.1007/s11010-009-0267-2] [Citation(s) in RCA: 307] [Impact Index Per Article: 21.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2009] [Accepted: 09/15/2009] [Indexed: 02/03/2023]
Abstract
NF-kappaB, a transcription factor first discovered in 1986, is now known to be closely connected to the process of tumorogenesis based on a multiplicity of evidence. (1) NF-kappaB is activated in response to tobacco, stress, dietary agents, obesity, alcohol, infectious agents, irradiation, and environmental stimuli that account for as much as 95% of all cancers. (2) The transcription factor has been linked with transformation of cells. (3) It is constitutively active in most tumor cells. (4) It has also been linked with the survival of cancer stem cells, an early progenitor cell that has acquired self-renewal potential. (5) NF-kappaB regulates the expression of most anti-apoptotic gene products associated with the survival of the tumor. (6) It also regulates the gene products linked with proliferation of tumors. (7) The transcription factor controls the expression of gene products linked with invasion, angiogenesis, and metastasis of cancer. (8) While most carcinogens activate NF-kappaB, most chemopreventive agents suppress its activation. These observations suggest that NF-kappaB is intimately intertwined with cancer growth and metastasis. The mechanism that leads to constitutive activation of NF-kappaB in hematological, gastrointestinal, genitourinary, gynecological, thoracic head and neck, breast, and skin cancers, and the ways NF-kappaB is activated are the topics of discussion in this review.
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Pedrosa AMDC, Weinlich R, Mognol GP, Robbs BK, Viola JPDB, Campa A, Amarante-Mendes GP. Melatonin protects CD4+ T cells from activation-induced cell death by blocking NFAT-mediated CD95 ligand upregulation. THE JOURNAL OF IMMUNOLOGY 2010; 184:3487-94. [PMID: 20181888 DOI: 10.4049/jimmunol.0902961] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Over the past 20 y, the hormone melatonin was found to be produced in extrapineal sites, including cells of the immune system. Despite the increasing data regarding the biological effects of melatonin on the regulation of the immune system, the effect of this molecule on T cell survival remains largely unknown. Activation-induced cell death plays a critical role in the maintenance of the homeostasis of the immune system by eliminating self-reactive or chronically stimulated T cells. Because activated T cells not only synthesize melatonin but also respond to it, we investigated whether melatonin could modulate activation-induced cell death. We found that melatonin protects human and murine CD4(+) T cells from apoptosis by inhibiting CD95 ligand mRNA and protein upregulation in response to TCR/CD3 stimulation. This inhibition is a result of the interference with calmodulin/calcineurin activation of NFAT that prevents the translocation of NFAT to the nucleus. Accordingly, melatonin has no effect on T cells transfected with a constitutively active form of NFAT capable of migrating to the nucleus and transactivating target genes in the absence of calcineurin activity. Our results revealed a novel biochemical pathway that regulates the expression of CD95 ligand and potentially other downstream targets of NFAT activation.
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Affiliation(s)
- Alziana Moreno da Cunha Pedrosa
- Departamento de Análises Clínica e Toxicológica, Faculdade de Ciências Farmacêuticas, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo Brazil
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RETRACTED ARTICLE: 67-kDa laminin receptor induces FasL expression and FasL-mediated apoptosis through the activation of c-Myc and the subsequent activation of the FasL promoter in human cholangiocarcinoma cells. J Cancer Res Clin Oncol 2010; 137:391. [PMID: 20155283 DOI: 10.1007/s00432-010-0804-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2009] [Accepted: 01/28/2010] [Indexed: 10/19/2022]
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124
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Bouchier-Hayes L, McBride S, van Geelen CM, Nance S, Lewis LK, Pinkoski MJ, Beere HM. Fas ligand gene expression is directly regulated by stress-inducible heat shock transcription factor-1. Cell Death Differ 2010; 17:1034-46. [DOI: 10.1038/cdd.2010.4] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
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125
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Lee SY, Cho JS, Yuk DY, Moon DC, Jung JK, Yoo HS, Lee YM, Han SB, Oh KW, Hong JT. Obovatol enhances docetaxel-induced prostate and colon cancer cell death through inactivation of nuclear transcription factor-kappaB. J Pharmacol Sci 2010; 111:124-36. [PMID: 19834284 DOI: 10.1254/jphs.09048fp] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
Abstract
Nuclear transcription factor-kappaB (NF-kappaB) is constitutively activated in prostate and colon cancers and is related with the resistance of cancer cells against chemotherapeutics. Previously, we found that obovatol, an active compound isolated from Magnolia obovata, inhibited cancer cell growth through inhibition of NF-kappaB activity. We investigated here whether obovatol could sensitize cancer cells against docetaxel through inhibition of NF-kappaB activity in prostate cancer (LNCaP and PC-3) and colon cancer (SW620 and HCT116) cells. The combination treatment with each drug at one half the respective IC(50) dose (5 microM obovatol + 5 nM docetaxel) was more effective and significant (60%-70%) in the inhibition of cancer cell growth than single treatment by each drug (20%-40%); inhibition was exerted through a significant increase of apoptosis induction (60%-80%) by the combination treatment compared to the single treatment (10%-30%). Correlating well with the synergistic inhibition (combination indices are less than 1 in all cell types), the combination significantly inhibited NF-kappaB activities as well as expression of NF-kappaB target apoptotic cell death proteins, but decreased anti-apoptotic cell death proteins. Similar combination effects of obovatol with other chemotherapeutic agents (paclitaxel, cisplatin, and doxorubicin) on the inhibition of cell growth and NF-kappaB activity were also found. These results indicate that obovatol augments cell growth inhibition by chemotherapeutics through inactivation of NF-kappaB and suggest that obovatol may have therapeutic advantages in the combination treatment with other chemotherapeutics. [Supplementary Figure: available only at http://dx.doi.org/10.1254/jphs.09048FP].
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Affiliation(s)
- So Yong Lee
- College of Pharmacy and CBITRC, Chungbuk National University, South Korea
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126
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Chen KC, Liu WH, Chang LS. Suppression of ERK signaling evokes autocrine Fas-mediated death in arachidonic acid-treated human chronic myeloid leukemia K562 cells. J Cell Physiol 2010; 222:625-34. [PMID: 19927299 DOI: 10.1002/jcp.21979] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Arachidonic acid (AA)-induced apoptotic death of K562 cells (human chronic myeloid leukemic cells) was characteristic of reactive oxygen species (ROS) generation and mitochondrial depolarization. N-Acetylcysteine pretreatment rescued viability of AA-treated cells and abolished mitochondrial depolarization. In contrast to no significant changes in phospho-JNK and phospho-ERK levels, AA evoked notable activation of p38 MAPK. Unlike that of JNK and p38 MAPK, ERK suppression further reduced the viability of AA-treated cells. Increases in Fas/FasL protein expression, caspase-8 activation, the production of tBid and the loss of mitochondrial membrane potential were noted with K562 cells that were treated with a combination of U0126 and AA. Down-regulation of FADD attenuated U0126-evoked degradation of procaspase-8 and Bid. Abolition of p38 MAPK activation abrogated U0126-elicited Fas/FasL up-regulation in AA-treated cells. U0126 pretreatment suppressed c-Fos phosphorylation but increased p38 MAPK-mediated c-Jun phosphorylation. Knock-down of c-Fos and c-Jun protein expression by siRNA suggested that c-Fos counteracted the effect of c-Jun on Fas/FasL up-regulation. Taken together, our data indicate that AA induces the ROS/mitochondria-dependent death pathway and blocks the ERK pathway which enhances the cytotoxicity of AA through additionally evoking an autocrine Fas-mediated apoptotic mechanism in K562 cells.
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Affiliation(s)
- Ku-Chung Chen
- Institute of Biomedical Sciences, Kaohsiung Medical University Joint Research Center, National Sun Yat-Sen University, Kaohsiung 804, Taiwan
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127
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Cho SH, Chung KS, Choi JH, Kim DH, Lee KT. Compound K, a metabolite of ginseng saponin, induces apoptosis via caspase-8-dependent pathway in HL-60 human leukemia cells. BMC Cancer 2009; 9:449. [PMID: 20017956 PMCID: PMC2806409 DOI: 10.1186/1471-2407-9-449] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2009] [Accepted: 12/18/2009] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Compound K [20-O-beta-(D-glucopyranosyl)-20(S)-protopanaxadiol], a metabolite of the protopanaxadiol-type saponins of Panax ginseng C.A. Meyer, has been reported to possess anti-tumor properties to inhibit angiogenesis and to induce tumor apoptosis. In the present study, we investigated the effect of Compound K on apoptosis and explored the underlying mechanisms involved in HL-60 human leukemia cells. METHODS We examined the effect of Compound K on the viabilities of various cancer cell lines using MTT assays. DAPI assay, Annexin V and PI double staining, Western blot assay and immunoprecipitation were used to determine the effect of Compound K on the induction of apoptosis. RESULTS Compound K was found to inhibit the viability of HL-60 cells in a dose- and time-dependent manner with an IC50 of 14 muM. Moreover, this cell death had typical features of apoptosis, that is, DNA fragmentation, DNA ladder formation, and the externalization of Annexin V targeted phosphatidylserine residues in HL-60 cells. In addition, compound-K induced a series of intracellular events associated with both the mitochondrial- and death receptor-dependent apoptotic pathways, namely, (1) the activation of caspases-3, -8, and -9; (2) the loss of mitochondrial membrane potential; (3) the release of cytochrome c and Smac/DIABLO to the cytosol; (4) the translocation of Bid and Bax to mitochondria; and (5) the downregulations of Bcl-2 and Bcl-xL. Furthermore, a caspase-8 inhibitor completely abolished caspase-3 activation, Bid cleavage, and subsequent DNA fragmentation by Compound K. Interestingly, the activation of caspase-3 and -8 and DNA fragmentation were significantly prevented in the presence of cycloheximide, suggesting that Compound K-induced apoptosis is dependent on de novo protein synthesis. CONCLUSIONS The results indicate that caspase-8 plays a key role in Compound K-stimulated apoptosis via the activation of caspase-3 directly or indirectly through Bid cleavage, cytochrome c release, and caspase-9 activation.
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Affiliation(s)
- Sung-Hee Cho
- Department of Pharmaceutical Biochemistry, College of Pharmacy, Kyung-Hee University, Seoul 130-701, South Korea
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128
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Liu WH, Chang LS. Arachidonic acid induces Fas and FasL upregulation in human leukemia U937 cells via Ca2+/ROS-mediated suppression of ERK/c-Fos pathway and activation of p38 MAPK/ATF-2 pathway. Toxicol Lett 2009; 191:140-8. [DOI: 10.1016/j.toxlet.2009.08.016] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2009] [Revised: 08/19/2009] [Accepted: 08/22/2009] [Indexed: 12/19/2022]
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129
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Chen KC, Chang LS. Notexin upregulates Fas and FasL protein expression of human neuroblastoma SK-N-SH cells through p38 MAPK/ATF-2 and JNK/c-Jun pathways. Toxicon 2009; 55:754-61. [PMID: 19944115 DOI: 10.1016/j.toxicon.2009.11.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2009] [Revised: 10/27/2009] [Accepted: 11/10/2009] [Indexed: 12/21/2022]
Abstract
Notechis scutatus scutatus notexin induced an increase in Fas and FasL protein expression of human neuroblastoma SK-N-SH cells in a dose- and time-dependent manner. Moreover, notexin treatment upregulated transcription of Fas/FasL mRNA. Downregulation of FADD blocked notexin-induced procaspase-8 degradation and cleavage of Bid and rescued viability of notexin-treated cells. Upon exposure to notexin, activation of JNK and p38 MAPK was observed in SK-N-SH cells. Notexin-induced upregulation of Fas and FasL was suppressed by SB202190 (p38 MAPK inhibitor) and S600125 (JNK inhibitor). Downregulation of p38alpha MAPK and JNK1 by siRNA proved that upregulation of Fas/FasL was related to p38alpha MAPK and JNK1 activation. Notexin treatment evoked p38alpha MAPK-mediated ATF-2 phosphorylation and JNK1-mediated c-Jun phosphorylation. Knockdown of c-Jun and ATF-2 by siRNA or overexpression of dominant-negative c-Jun and ATF-2 revealed that both c-Jun and ATF-2 were crucial for Fas/FasL upregulation. Taken together, our data indicate that notexin-induced upregulation of Fas and FasL is triggered by p38 MAPK/ATF-2 and JNK/c-Jun signaling pathways in SK-N-SH cells.
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Affiliation(s)
- Ku-Chung Chen
- Institute of Biomedical Sciences, National Sun Yat-Sen University-Kaohsiung Medical University Joint Research Center, National Sun Yat-Sen University, Kaohsiung 804, Taiwan
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130
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Chen KC, Chiou YL, Chang LS. JNK1/c-Jun and p38α MAPK/ATF-2 pathways are responsible for upregulation of Fas/FasL in human chronic myeloid leukemia K562 cells upon exposure to Taiwan cobra phospholipase A2. J Cell Biochem 2009; 108:612-20. [DOI: 10.1002/jcb.22293] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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131
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Affiliation(s)
- Mats Ljungman
- Division of Radiation and Cancer Biology, Department of Radiation Oncology, University of Michigan Comprehensive Cancer Center, Ann Arbor, Michigan 48109, USA.
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132
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Skladanowski A, Bozko P, Sabisz M. DNA structure and integrity checkpoints during the cell cycle and their role in drug targeting and sensitivity of tumor cells to anticancer treatment. Chem Rev 2009; 109:2951-73. [PMID: 19522503 DOI: 10.1021/cr900026u] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Andrzej Skladanowski
- Department of Pharmaceutical Technology and Biochemistry, Faculty of Chemistry, Gdansk University of Technology, Gdansk, Poland.
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133
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Chen F, Beezhold K, Castranova V. Tumor Promoting or Tumor Suppressing of NF-κ B, a Matter of Cell Context Dependency. Int Rev Immunol 2009; 27:183-204. [DOI: 10.1080/08830180802130327] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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134
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Tan NY, Li JM, Stocker R, Khachigian LM. Angiotensin II-inducible smooth muscle cell apoptosis involves the angiotensin II type 2 receptor, GATA-6 activation, and FasL-Fas engagement. Circ Res 2009; 105:422-30. [PMID: 19628789 DOI: 10.1161/circresaha.109.203323] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
RATIONALE Fas ligand (FasL)-mediated smooth muscle cell (SMC) apoptosis within the vulnerable plaque may lead to plaque instability and rupture, events that underlie myocardial infarction and stroke. OBJECTIVE The molecular mechanisms underlying FasL transcription and FasL-dependent SMC apoptosis were investigated in this study in vitro and in vivo. METHODS AND RESULTS We demonstrate that GATA-6, the predominant GATA family member expressed in SMCs, stimulates SMC apoptosis in an extracellular FasL-dependent manner. Both GATA-6 and FasL were inducibly and transiently expressed following balloon injury to rat carotid arteries. We identified two potential GATA binding in the FasL promoter and demonstrated using DNA binding and chromatin immunoprecipitation assays that GATA-6 regulates FasL through one ((-298)TTATCA(-303)) but not both these elements. Angiotensin II (Ang II) stimulated expression of both GATA-6 and FasL. Ang II increased SMC apoptosis in an Ang II type 2 receptor-, caspase 8-, and FasL-dependent fashion. GATA-6 activation was MEK-ERK1/2- and JNK-dependent, and GATA-6 small interfering RNA blocked Ang II-inducible FasL expression and SMC apoptosis. Administration of Ang II to rats increased FasL expression and apoptosis in carotid artery SMCs in an Ang II type 2 receptor- and GATA-6-dependent manner. CONCLUSIONS This study provides new insights into the transcriptional events underpinning FasL-dependent SMC apoptosis after exposure to Ang II.
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Affiliation(s)
- Nicole Y Tan
- Centre for Vascular Research, University of New South Wales, Sydney NSW 2052, Australia
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135
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p,p'-DDE induces apoptosis of rat Sertoli cells via a FasL-dependent pathway. J Biomed Biotechnol 2009; 2009:181282. [PMID: 19644561 PMCID: PMC2717566 DOI: 10.1155/2009/181282] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2009] [Accepted: 05/20/2009] [Indexed: 01/17/2023] Open
Abstract
One,1-dichloro-2,2 bis(p-chlorophenyl) ethylene (p,p′-DDE), the major metabolite of 2,2-bis(4-Chlorophenyl)-1,1,1-trichloroethane (DDT), is a known persistent organic pollutant and male reproductive toxicant. It has antiandrogenic effect. However, the mechanism by which p,p′-DDE exposure causes male reproductive
toxicity remains unknown. In the present study, rat Sertoli cells were used to investigate the molecular mechanism involved in p,p′-DDE-induced toxicity in male reproductive system. The results indicated that p,p′-DDE exposure at over 30 μM showed the induction of apoptotic cell death. p,p′-DDE could induce increases in FasL mRNA and protein, which could be blocked by an antioxidant agent, N-acetyl-l-cysteine (NAC). In addition, caspase-3 and -8 were activated by p,p′-DDE treatment in these cells. The activation of NF-κB was enhanced with the increase of p,p′-DDE dose. Taken together, these results suggested that exposure to p,p′-DDE might induce apoptosis of rat Sertoli cells through a FasL-dependent pathway.
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Rapisarda V, Carnazza ML, Caltabiano C, Loreto C, Musumeci G, Valentino M, Martinez G. Bitumen products induce skin cell apoptosis in chronically exposed road pavers. J Cutan Pathol 2009; 36:781-7. [PMID: 19519609 DOI: 10.1111/j.1600-0560.2008.01140.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
BACKGROUND Worker's exposure to bitumen fumes, via inhalation and skin contamination, is related to adverse effects including an increased risk of lung, stomach and non-melanoma skin cancers and leukaemia. The two major mechanisms regulating apoptosis include the mitochondria-mediated intrinsic pathway and the extrinsic pathway induced by death signalling ligands. In a previous study, we showed activation of apoptosis-regulating proteins BAX and BCL-2 in road pavers chronically exposed to bitumen fumes. These molecules play a central role in activation of programmed cell death by the intrinsic pathway. In this study, we hypothesized that the apoptosis mechanism could be activated in the skin of road pavers chronically exposed to bitumen fumes also through the extrinsic pathway, via mediation by tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) and its death receptor, DR5. METHODS Skin punch biopsies from 16 occupationally exposed workers and a control group were processed immunohistochemically for TRAIL and DR5. Activation of programmed cell death was also investigated by expression of caspase-3 and visualization of DNA strand breaks. RESULTS AND CONCLUSION TRAIL, DR5 and caspase-3 overexpression and enhanced Terminal Deoxynucleotidyl Transferase Mediated dUTP Nick End Labeling (TUNEL) positivity were found in chronically bitumen-exposed skin, suggesting activation of apoptosis as a defence mechanism.
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Affiliation(s)
- Venerando Rapisarda
- Department of Molecular Pathology, Polytechnic University of Marche, Ancona, Italy
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137
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Lewis-Wambi JS, Jordan VC. Estrogen regulation of apoptosis: how can one hormone stimulate and inhibit? Breast Cancer Res 2009; 11:206. [PMID: 19519952 PMCID: PMC2716493 DOI: 10.1186/bcr2255] [Citation(s) in RCA: 178] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The link between estrogen and the development and proliferation of breast cancer is well documented. Estrogen stimulates growth and inhibits apoptosis through estrogen receptor-mediated mechanisms in many cell types. Interestingly, there is strong evidence that estrogen induces apoptosis in breast cancer and other cell types. Forty years ago, before the development of tamoxifen, high-dose estrogen was used to induce tumor regression of hormone-dependent breast cancer in post-menopausal women. While the mechanisms by which estrogen induces apoptosis were not completely known, recent evidence from our laboratory and others demonstrates the involvement of the extrinsic (Fas/FasL) and the intrinsic (mitochondria) pathways in this process. We discuss the different apoptotic signaling pathways involved in E2 (17beta-estradiol)-induced apoptosis, including the intrinsic and extrinsic apoptosis pathways, the NF-kappaB (nuclear factor-kappa-B)-mediated survival pathway as well as the PI3K (phosphoinositide 3-kinase)/Akt signaling pathway. Breast cancer cells can also be sensitized to estrogen-induced apoptosis through suppression of glutathione by BSO (L-buthionine sulfoximine). This finding has implications for the control of breast cancer with low-dose estrogen and other targeted therapeutic drugs.
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Affiliation(s)
- Joan S Lewis-Wambi
- Fox Chase Cancer Center, 333 Cottman Avenue, Philadelphia, PA 19111, USA
| | - V Craig Jordan
- Fox Chase Cancer Center, 333 Cottman Avenue, Philadelphia, PA 19111, USA
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Kim SM, Lee SY, Yuk DY, Moon DC, Choi SS, Kim Y, Han SB, Oh KW, Hong JT. Inhibition of NF-kappaB by ginsenoside Rg3 enhances the susceptibility of colon cancer cells to docetaxel. Arch Pharm Res 2009; 32:755-65. [PMID: 19471891 DOI: 10.1007/s12272-009-1515-4] [Citation(s) in RCA: 92] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2008] [Revised: 03/02/2009] [Accepted: 03/09/2009] [Indexed: 01/19/2023]
Abstract
Ginsenoside Rg3, the main constituent isolated from Panax ginseng, has been of interest for use as a cancer preventive or therapeutic agent. We investigated here whether Rg3 can inhibit the activity of NF-kappaB, a key transcriptional factor constitutively activated in colon cancer that confers cancer cell resistance to chemotherapeutic agents. To investigate whether RG3 can suppress activation of NF-kappaB, and thus inhibit cancer cell growth, we examined the susceptibility of colon cancer cells (SW620 and HCT116) to treatment with Rg3 (25, 50, 75, 100 microM) and RG3-induced activation of NF-kappaB. RG3 dose-dependently inhibited cancer cell growth through induction of apoptosis and decreased NF-kappaB activity. In a further study of compounds in colon cancer, we used half of the IC(50) dose, values in combined treatments of Rg3 (50 microM) with conventional agents - docetaxel (5 nM), paclitaxel (10 nM) cisplatin (10 microM) and doxorubicin (2 microM). Compared to treatment with Rg3 or chemotherapy alone, combined treatment was more effective (i.e., there were synergistic effects) in the inhibition of cancer cell growth and induction of apoptosis and these effects were accompanied by significant inhibition of NF-kappaB activity. NF-kappaB target gene expression of apoptotic cell death proteins (Bax, caspase-3, caspase-9) was significantly enhanced, but the expression of anti-apoptotic genes and cell proliferation marker genes (Bcl-2, inhibitor of apoptosis protein (IAP-1) and X chromosome IAP (XIAP), Cox-2, c-Fos, c-Jun and cyclin D1) was significantly inhibited by the combined treatment compared to Rg3 or docetaxel alone. These results indicate that ginsenoside Rg3 inhibits NF-kappaB, and enhances the susceptibility of colon cancer cells to docetaxel and other chemotherapeutics. Thus, ginsenoside Rg3 could be useful as an anti-cancer or adjuvant anti-cancer agent.
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Affiliation(s)
- Sun Mi Kim
- College of Pharmacy, Chungbuk National University, Cheongju, 361-763, Korea
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139
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Xia Y, Ongusaha P, Lee SW, Liou YC. Loss of Wip1 sensitizes cells to stress- and DNA damage-induced apoptosis. J Biol Chem 2009; 284:17428-37. [PMID: 19395378 DOI: 10.1074/jbc.m109.007823] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
In response to various environmental stresses, the stress-responsive MAPKs p38 and JNK are activated and phosphorylate ATF2 and c-Jun transcription factors, thereby affecting cell-fate decision. Targeted gene disruption studies have established that JNK-c-Jun signaling plays a vital role in stress-induced apoptosis. The oncogenic phosphatase Wip1 acts as an important regulator in DNA damage pathway by dephosphorylating a spectrum of proteins including p53, p38, Chk1, Chk2, and ATM. In this study we show that Wip1 negatively regulates the activation of MKK4-JNK-c-Jun signaling during stress-induced apoptosis. The loss of Wip1 function sensitizes mouse embryonic fibroblasts to stress-induced apoptosis via the activation of both p38-ATF2 and JNK-c-Jun signaling. Here we reveal that Wip1 has dual roles in alternatively regulating stress- and DNA damage-induced apoptosis through p38/JNK MAPKs and p38/p53-dependent pathways, respectively. Our results point to Wip1 as a general regulator of apoptosis, which further supports its role in tumorigenesis.
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Affiliation(s)
- Yun Xia
- Department of Biological Sciences, Faculty of Science, National University of Singapore, Singapore 117543, Singapore
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140
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Zhu JY, Giaisi M, Köhler R, Müller WW, Mühleisen A, Proksch P, Krammer PH, Li-Weber M. Rocaglamide sensitizes leukemic T cells to activation-induced cell death by differential regulation of CD95L and c-FLIP expression. Cell Death Differ 2009; 16:1289-99. [DOI: 10.1038/cdd.2009.42] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
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141
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Shelton SN, Shawgo ME, Robertson JD. Cleavage of Bid by executioner caspases mediates feed forward amplification of mitochondrial outer membrane permeabilization during genotoxic stress-induced apoptosis in Jurkat cells. J Biol Chem 2009; 284:11247-55. [PMID: 19233849 DOI: 10.1074/jbc.m809392200] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
The extent to which the BH3-only protein Bid is important for intrinsic (mitochondria-mediated) apoptotic cell death induced by genotoxic stress remains controversial. In the present study, we examine this issue using a panel of gene-manipulated Bax-deficient Jurkat T-lymphocytes. Cells stably depleted of Bid were far less sensitive than control-transfected cells to etoposide-induced apoptosis. In particular, drug-induced Bak activation, cytochrome c release, loss of mitochondrial membrane potential, and caspase activation were all decreased in cells lacking Bid. Reconstitution experiments using recombinant proteins and permeabilized Bid-deficient cells demonstrated that truncated Bid (tBid), but not full-length Bid, potently induced Bak activation and the release of cytochrome c. Further, caspase-8-deficient Jurkat cells efficiently cleaved Bid and were sensitive to drug-induced apoptosis. By comparison, Apaf-1-deficient cells, as well as cells overexpressing full-length X-linked inhibitor of apoptosis protein (XIAP) or the BIR1/BIR2 domains of XIAP, failed to cleave Bid in response to genotoxic stress. These data suggest that tBid plays an important regulatory role in the execution of DNA damage-induced cytochrome c release and apoptosis. However, the fact that cleavage of Bid to tBid is mediated by executioner caspases suggests that a self-amplifying feed forward loop involving caspases, Bid, and mitochondria may help determine irreversible commitment to apoptosis.
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Affiliation(s)
- Shary N Shelton
- Department of Pharmacology, Toxicology & Therapeutics and the Kansas University Cancer Center, University of Kansas Medical Center, Kansas City, Kansas 66160, USA
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142
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Aziz MH, Sundling KE, Dreckschmidt NE, Verma AK. Protein kinase Cepsilon inhibits UVR-induced expression of FADD, an adaptor protein, linked to both Fas- and TNFR1-mediated apoptosis. J Invest Dermatol 2009; 129:2011-21. [PMID: 19194472 DOI: 10.1038/jid.2008.458] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Protein kinase C (PKC)epsilon overexpression in FVB/N transgenic mice sensitized skin to UVR-induced development of squamous cell carcinomas and suppressed formation of sunburn cells, which are DNA-damaged keratinocytes undergoing apoptosis. Here, we elucidated the mechanisms associated with the inhibition of UVR-induced appearance of sunburn cells in PKCepsilon transgenic mice. We found that the inhibition of UVR-induced sunburn cell formation in PKCepsilon transgenic mice may be the result of the inhibition of the expression of Fas, Fas ligand, and the mammalian death adaptor protein termed Fas-associated with death domain (FADD). The adaptor protein FADD is the key component of the death-inducing signaling complex of both Fas and tumor necrosis factor receptor 1. A decreased expression of epidermal FADD was observed after a single UVR exposure. However, a complete loss of FADD expression was found after four (Monday, Wednesday, Friday, and Monday) repeated UVR exposures. FADD transmits apoptotic signals from death receptors to the downstream initiator caspase-8 and connects to the mitochondrial intrinsic apoptotic signal transduction pathway by the cleavage of Bid, a Bcl-2 family member. PKCepsilon-mediated loss of FADD expression inhibited UVR signals to the activation of both extrinsic and intrinsic apoptotic pathways.
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Affiliation(s)
- Moammir Hasan Aziz
- Department of Human Oncology, Medical School, University of Wisconsin, Madison, Wisconsin 53792, USA
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143
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Kadohara K, Nagumo M, Asami S, Tsukumo Y, Sugimoto H, Igarashi M, Nagai K, Kataoka T. Caspase-8 Mediates Mitochondrial Release of Pro-apoptotic Proteins in a Manner Independent of Its Proteolytic Activity in Apoptosis Induced by the Protein Synthesis Inhibitor Acetoxycycloheximide in Human Leukemia Jurkat Cells. J Biol Chem 2009; 284:5478-87. [DOI: 10.1074/jbc.m808523200] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
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144
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Jimi E, Strickland I, Voll RE, Long M, Ghosh S. Differential role of the transcription factor NF-kappaB in selection and survival of CD4+ and CD8+ thymocytes. Immunity 2008; 29:523-37. [PMID: 18957265 DOI: 10.1016/j.immuni.2008.08.010] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2006] [Revised: 03/12/2008] [Accepted: 08/11/2008] [Indexed: 01/30/2023]
Abstract
Inhibition of the transcription factor nuclear factor (NF)-kappaB activity leads to a reduction in numbers of CD8(+) single-positive (SP) thymocytes, suggesting a selective role for NF-kappaB in these cells. To further explore the role of NF-kappaB in SP thymocytes, we utilized transgenic models that allowed either inhibition or activation of NF-kappaB. We showed that activation of NF-kappaB played an important role in the selection of major histocompatibility complex (MHC) class I-restricted CD8(+) T cells. Surprisingly, NF-kappaB was not activated in positively selected CD4(+) thymocytes, and inhibition of NF-kappaB did not perturb positive or negative selection of CD4(+) cells. However, enforced activation of NF-kappaB via a constitutively active inhibitor of kappaB (IkappaB) kinase transgene led to a nearly complete deletion of CD4 cells by pushing positively selecting CD4(+) cells into negative selection. These studies therefore revealed a surprising difference of NF-kappaB activation in CD4(+) and CD8(+) thymocytes and suggested that NF-kappaB contributes to the establishment of thresholds of signaling that determine positive or negative selection of thymocytes.
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Affiliation(s)
- Eijiro Jimi
- Department of Immunobiology, Yale University School of Medicine, New Haven, CT 06520, USA
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145
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Sodhi A, Sethi G. Involvement of Fas/Fas Ligand in Ultraviolet B-Induced Apoptosis of Murine Peritoneal Macrophages. Toxicol Mech Methods 2008; 14:215-22. [DOI: 10.1080/15376520490434449] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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146
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Shawgo ME, Shelton SN, Robertson JD. Caspase-mediated Bak activation and cytochrome c release during intrinsic apoptotic cell death in Jurkat cells. J Biol Chem 2008; 283:35532-8. [PMID: 18927073 DOI: 10.1074/jbc.m807656200] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Mitochondrial outer membrane permeabilization and the release of intermembrane space proteins, such as cytochrome c, are early events during intrinsic (mitochondria-mediated) apoptotic signaling. Although this process is generally accepted to require the activation of Bak or Bax, the underlying mechanism responsible for their activation during true intrinsic apoptosis is not well understood. In the current study, we investigated the molecular requirements necessary for Bak activation using distinct clones of Bax-deficient Jurkat T-lymphocytes in which the intrinsic pathway had been inhibited. Cells stably overexpressing Bcl-2/Bcl-x(L) or stably depleted of Apaf-1 were equally resistant to apoptosis induced by the DNA-damaging anticancer drug etoposide as determined by phosphatidylserine externalization and caspase activation. Strikingly, characterization of mitochondrial apoptotic events in all three drug-resistant cell lines revealed that, without exception, resistance to apoptosis was associated with an absence of Bak activation, cytochrome c release, and mitochondrial membrane depolarization. Furthermore, we found that etoposide-induced apoptosis and mitochondrial events were inhibited in cells stably overexpressing either full-length X-linked inhibitor of apoptosis protein (XIAP) or the BIR1/BIR2 domains of XIAP. Combined, our findings suggest that caspase-mediated positive amplification of initial mitochondrial changes can determine the threshold for irreversible activation of the intrinsic apoptotic pathway.
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Affiliation(s)
- Mary E Shawgo
- Department of Pharmacology, University of Kansas Medical Center, Kansas City, Kansas 66160, USA
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147
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Blockade of the Fas/Fas ligand interaction suppresses hepatocyte apoptosis in ischemia-reperfusion rat liver. Apoptosis 2008; 13:1013-21. [PMID: 18561025 DOI: 10.1007/s10495-008-0234-5] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Hepatic ischemia-reperfusion injury remains a significant problem for liver surgery, including transplantation, and apoptosis has been implicated in this type of hepatic injury. Here we found that through the Fas/Fas ligand interaction apoptosis is involved in the late phase of hepatic ischemia-reperfusion injury. The appearance of apoptotic hepatocytes increases significantly after reperfusion, reaching a maximum 12 h after reperfusion. The transcription levels of Fas and Fas ligand are increased after reperfusion. Fas is expressed on hepatocytes, while Fas ligand is expressed on infiltrating immune cells. A close spatial and temporal association of Fas expression and apoptotic cells is demonstrated in the histological observation. These results suggest that infiltrating cells induce apoptosis of hepatocytes through the Fas/Fas ligand interaction, leading to hepatocyte injury. Furthermore, an injection of anti-Fas antibody or neutralizing anti-Fas ligand antibody results in a dramatic decrease in the occurrence of hepatocyte apoptosis and hepatic infiltration of macrophages and natural killer cells as well as liver injury. Our results suggest that blockage of the Fas/Fas ligand interaction is a promising strategy for suppression of hepatic ischemia-reperfusion injury.
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148
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Atanasov AG, Leiser D, Roesselet C, Noti M, Corazza N, Schoonjans K, Brunner T. Cell cycle-dependent regulation of extra-adrenal glucocorticoid synthesis in murine intestinal epithelial cells. FASEB J 2008; 22:4117-25. [PMID: 18711026 DOI: 10.1096/fj.08-114157] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Glucocorticoids are anti-inflammatory steroids with important applications in the treatment of inflammatory diseases. Endogenous glucocorticoids are mainly produced by the adrenal glands, although there is increasing evidence for extra-adrenal sources. Recent findings show that intestinal crypt cells produce glucocorticoids, which contribute to the maintenance of intestinal immune homeostasis. Intestinal glucocorticoid synthesis is critically regulated by the transcription factor liver receptor homologue-1 (LRH-1). As expression of steroidogenic enzymes and LRH-1 is restricted to the proliferating cells of the crypts, we aimed to investigate the role of the cell cycle in the regulation of LRH-1 activity and intestinal glucocorticoid synthesis. We here show that either pharmacological or molecular modulation of cell cycle progression significantly inhibited expression of steroidogenic enzymes and synthesis of glucocorticoids in intestinal epithelial cells. Synchronization of intestinal epithelial cells in the cell cycle revealed that expression of steroidogenic enzymes is preferentially induced at the G(1)/S stage. Differentiation of immature intestinal epithelial cells to mature nonproliferating cells also resulted in reduced expression of steroidogenic enzymes. This cell cycle-related effect on intestinal steroidogenesis was found to be mediated through the regulation of LRH-1 transcriptional activity. This mechanism may restrict intestinal glucocorticoid synthesis to the proliferating cells of the crypts.
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Affiliation(s)
- Atanas G Atanasov
- Division of Immunopathology, Institute of Pathology, University of Bern, Murtenstrasse 31, 3010 Bern, Switzerland
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149
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Abstract
Apoptosis is an evolutionarily conserved mode of cell death that is tightly regulated and critical for multicellular organism development and cellular homeostasis. Specific biochemical and morphological changes characterise cells undergoing apoptosis, and reflect the specificity in which activated apoptotic pathways follow. The two best-characterized apoptotic pathways are the extrinsic pathway and the intrinsic pathway, which involve cell surface death receptors and the mitochondria and endoplasmic reticulum respectively. Apoptotic stimuli lead to activation of either or both of these pathways, and involve sequential activation of different cysteine proteases (caspases), and in the case of the intrinsic pathway, activation of a family of Bcl-2 proteins that critically regulate cell death. Conversely, dis-inhibition of endogenous inhibitors is often required for effective apoptotic cell death. Furthermore, an interesting recurring protein-protein interaction within this framework of apoptotic cascades involves interactions between death domain motifs that are present on many of the regulatory proteins in both apoptotic pathways. Cardiomyocyte apoptosis has been demonstrated in human heart failure and in rodents, apoptosis itself directly causes dilated cardiomyopathy. Understanding the intricacies of apoptotic death pathways and determining the relevance of these to cardiomyopathy is therefore essential if cardiomyocyte apoptosis is to be a pharmacological target for heart failure therapy.
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150
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