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Armstrong MJ, Stang MT, Liu Y, Yan J, Pizzoferrato E, Yim JH. IRF-1 inhibits NF-κB activity, suppresses TRAF2 and cIAP1 and induces breast cancer cell specific growth inhibition. Cancer Biol Ther 2016; 16:1029-41. [PMID: 26011589 DOI: 10.1080/15384047.2015.1046646] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
Abstract
Interferon Regulatory Factor (IRF)-1, originally identified as a transcription factor of the human interferon (IFN)-β gene, mediates tumor suppression and may inhibit oncogenesis. We have shown that IRF-1 in human breast cancer cells results in the down-regulation of survivin, tumor cell death, and the inhibition of tumor growth in vivo in xenogeneic mouse models. In this current report, we initiate studies comparing the effect of IRF-1 in human nonmalignant breast cell and breast cancer cell lines. While IRF-1 in breast cancer cells results in growth inhibition and cell death, profound growth inhibition and cell death are not observed in nonmalignant human breast cells. We show that TNF-α or IFN-γ induces IRF-1 in breast cancer cells and results in enhanced cell death. Abrogation of IRF-1 diminishes TNF-α and IFN-γ-induced apoptosis. We test the hypothesis that IRF-1 augments TNF-α-induced apoptosis in breast cancer cells. Potential signaling networks elicited by IRF-1 are investigated by evaluating the NF-κB pathway. TNF-α and/or IFN-γ results in decreased presence of NF-κB p65 in the nucleus of breast cancer cells. While TNF-α and/or IFN-γ can induce IRF-1 in nonmalignant breast cells, a marked change in NF-κB p65 is not observed. Moreover, the ectopic expression of IRF-1 in breast cancer cells results in caspase-3, -7, -8 cleavage, inhibits NF-κB activity, and suppresses the expression of molecules involved in the NF-κB pathway. These data show that IRF-1 in human breast cancer cells elicits multiple signaling networks including intrinsic and extrinsic cell death and down-regulates molecules involved in the NF-κB pathway.
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Key Words
- Ad, adenovirus
- Cdk, cyclin-dependent kinase
- DISC, death-inducing signaling complex
- DMEM, Dulbecco's Modified Eagle's Medium
- DR, death receptor
- EGFP, enhanced green fluorescent protein
- ER, estrogen receptor
- FADD, fas-associated death domain
- FBS, Fetal Bovine Serum
- FITC, fluorescein isothiocyanate
- FLICE, fas-associated death domain protein interleukin-1 β-converting enzyme
- IAP
- IFN-β, interferon-β
- IFN-γ, interferon-gamma
- IKK, IκB, kinase complex
- IRF-1
- IRF-1, interferon regulatory factor-1
- IκB, Inhibitory kappaB
- MOI, multiplicity of infection
- MTT, methylthiazoltetrazolium
- NEMO, NF-κB essential modulator
- NF-κB
- NF-κB, nuclear factor of kappa Beta
- RIP1, receptor interacting protein 1
- SCID, severe combined immunodeficiency
- STAT, signal transducer and activator of transcription
- Smac/DIABLO, Second mitochondria-derived activator of caspase/Direct IAP-binding protein with low pI
- TNF-α, tumor necrosis factor-α
- TNFR, tumor necrosis factor receptor
- TRADD, TNF receptor associated protein with a death domain
- TRAF2, tumor necrosis factor receptor-associated factor 2
- TRAIL, tumor necrosis factor-related apoptosis-inducing ligand
- XIAP, X-linked inhibitor of apoptosis protein
- apoptosis
- breast cancer
- cFLIP, cellular FLICE inhibitory protein
- cIAP1, c-inhibitor of apoptosis
- p53
- siRNA, small interfering RNA
- tumor suppressor
- β-gal, β-galactosidase
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Affiliation(s)
- Michaele J Armstrong
- a Department of Surgery; University of Pittsburgh School of Medicine ; Pittsburgh , PA , USA
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Sakamaki K, Iwabe N, Iwata H, Imai K, Takagi C, Chiba K, Shukunami C, Tomii K, Ueno N. Conservation of structure and function in vertebrate c-FLIP proteins despite rapid evolutionary change. Biochem Biophys Rep 2015; 3:175-189. [PMID: 29124180 PMCID: PMC5668880 DOI: 10.1016/j.bbrep.2015.08.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2015] [Revised: 08/05/2015] [Accepted: 08/05/2015] [Indexed: 12/26/2022] Open
Abstract
Cellular FLICE-like inhibitory protein (c-FLIP, gene symbol CFLAR) was first identified as a negative regulator of death receptor-mediated apoptosis in mammals. To understand the ubiquity and diversity of the c-FLIP protein subfamily during evolution, c-FLIP orthologs were identified from a comprehensive range of vertebrates, including birds, amphibians, and fish, and were characterized by combining experimental and computational analysis. Predictions of three-dimensional protein structures and molecular phylogenetic analysis indicated that the conserved structural features of c-FLIP proteins are all derived from an ancestral caspase-8, although they rapidly diverged from the subfamily consisting of caspases-8, -10, and -18. The functional role of the c-FLIP subfamily members is nearly ubiquitous throughout vertebrates. Exogenous expression of non-mammalian c-FLIP proteins in cultured mammalian cells suppressed death receptor-mediated apoptosis, implying that all of these proteins possess anti-apoptotic activity. Furthermore, non-mammalian c-FLIP proteins induced NF-κB activation much like their mammalian counterparts. The CFLAR mRNAs were synthesized during frog and fish embryogenesis. Overexpression of a truncated mutant of c-FLIP in the Xenopus laevis embryos by mRNA microinjection caused thorax edema and abnormal constriction of the abdomen. Depletion of cflar transcripts in zebrafish resulted in developmental abnormalities accompanied by edema and irregular red blood cell flow. Thus, our results demonstrate that c-FLIP/CFLAR is conserved in both protein structure and function in several vertebrate species, and suggest a significant role of c-FLIP in embryonic development.
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Key Words
- Apoptosis
- CARD, caspase-recruitment domain
- CASc, Caspase, interleukin-1 β converting enzyme homologs
- CHX, cycloheximide
- Caspase-8
- DED, death effector domain
- EGFP, enhanced green fluorescent protein
- Embryogenesis
- Evolution
- FADD, Fas-associated death domain protein
- MO, morpholino oligonucleotide
- NF-κB
- NF-κB, Nuclear factor-kappa B
- ODC, ornithine decarboxylase
- PCR, polymerase chain reaction
- Pseudocatalytic triad
- RT-PCR, reverse transcription-polymerase chain reaction
- TRAF2, tumor necrosis factor receptor-associated factor 2
- c-FLIP, cellular FLICE-like inhibitory protein
- tubα6, tubulin α6
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Affiliation(s)
- Kazuhiro Sakamaki
- Department of Animal Development and Physiology, Graduate School of Biostudies, Kyoto University, Kyoto 606-8501, Japan
| | - Naoyuki Iwabe
- Department of Biophysics, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan
| | - Hiroaki Iwata
- Multi-scale Research Center for Medical Science, Medical Institute of Bioregulation, Kyushu University, Fukuoka 812-8582, Japan
| | - Kenichiro Imai
- Biotechnology Research Institute for Drug Discovery, Department of Life Science and Biotechnology, National Institute of Advanced Industrial Science and Technology (AIST), Tokyo 135-0064, Japan
| | - Chiyo Takagi
- Department of Developmental Biology, National Institute for Basic Biology, Okazaki 444-8585, Japan
| | - Kumiko Chiba
- Department of Animal Development and Physiology, Graduate School of Biostudies, Kyoto University, Kyoto 606-8501, Japan
| | - Chisa Shukunami
- Department of Cellular Differentiation, Institute for Frontier Medical Sciences, Kyoto University, Kyoto 606-8507, Japan
| | - Kentaro Tomii
- Biotechnology Research Institute for Drug Discovery, Department of Life Science and Biotechnology, National Institute of Advanced Industrial Science and Technology (AIST), Tokyo 135-0064, Japan
| | - Naoto Ueno
- Department of Developmental Biology, National Institute for Basic Biology, Okazaki 444-8585, Japan
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