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Interferon regulatory factor 1 (IRF-1) downregulates Checkpoint kinase 1 (CHK1) through miR-195 to upregulate apoptosis and PD-L1 expression in Hepatocellular carcinoma (HCC) cells. Br J Cancer 2021; 125:101-111. [PMID: 33772151 DOI: 10.1038/s41416-021-01337-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2021] [Revised: 02/03/2021] [Accepted: 02/25/2021] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND CHK1 is considered an oncogene with overexpression in numerous cancers. However, CHK1 signalling regulation in hepatocellular carcinoma (HCC) remains unclear. METHODS CHEK1 mRNA, protein, pri-miR-195 and miR-195 expression in HCC tissue was determined by qPCR, WB and IF staining assay. Survival analyses in HCC with high- and low-CHEK1 mRNA expression was performed using TCGA database. Relative luciferase activity was investigated in HCC cells transfected with p-CHEK1 3'UTR. Apoptosis was detected by TUNEL assay. NK and CD8+ T cells were analysed by flow cytometry. RESULTS CHK1 is increased in human HCC tumours compared with non-cancerous liver. High CHK1 predicts worse prognosis. IFN-γ suppresses CHK1 via IRF-1 in HCC cells. The molecular mechanism of IRF-1 suppressing CHK1 is post-transcriptional by promoting miR-195 binding to CHEK1 mRNA 3'UTR, which exerts a translational blockade. Upregulated IRF-1 inhibits CHK1, which induces apoptosis of HCC cells. Likewise, CHK1 inhibition augments cellular apoptosis in HCC tumours. This effect may be a result of increased tumour NK cell infiltration. However, IRF-1 expression or CHK1 inhibition also upregulates PD-L1 expression via increased STAT3 phosphorylation. CONCLUSIONS IRF-1 induces miR-195 to suppress CHK1 protein expression. Both increased IRF-1 and decreased CHK1 upregulate cellular apoptosis and PD-L1 expression in HCC.
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Garvin AJ, Khalaf AHA, Rettino A, Xicluna J, Butler L, Morris JR, Heery DM, Clarke NM. GSK3β-SCFFBXW7α mediated phosphorylation and ubiquitination of IRF1 are required for its transcription-dependent turnover. Nucleic Acids Res 2019; 47:4476-4494. [PMID: 30854564 PMCID: PMC6511875 DOI: 10.1093/nar/gkz163] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Revised: 02/19/2019] [Accepted: 03/07/2019] [Indexed: 01/03/2023] Open
Abstract
IRF1 (Interferon Regulatory Factor-1) is the prototype of the IRF family of DNA binding transcription factors. IRF1 protein expression is regulated by transient up-regulation in response to external stimuli followed by rapid degradation via the ubiquitin-proteasome system. Here we report that DNA bound IRF1 turnover is promoted by GSK3β (Glycogen Synthase Kinase 3β) via phosphorylation of the T181 residue which generates a phosphodegron for the SCF (Skp-Cul-Fbox) ubiquitin E3-ligase receptor protein Fbxw7α (F-box/WD40 7). This regulated turnover is essential for IRF1 activity, as mutation of T181 results in an improperly stabilized protein that accumulates at target promoters but fails to induce RNA-Pol-II elongation and subsequent transcription of target genes. Consequently, the anti-proliferative activity of IRF1 is lost in cell lines expressing T181A mutant. Further, cell lines with dysfunctional Fbxw7 are less sensitive to IRF1 overexpression, suggesting an important co-activator function for this ligase complex. As T181 phosphorylation requires both DNA binding and RNA-Pol-II elongation, we propose that this event acts to clear ‘spent’ molecules of IRF1 from transcriptionally engaged target promoters.
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Affiliation(s)
- Alexander J Garvin
- School of Pharmacy, University of Nottingham, University Park, Nottingham, UK.,Institute of Cancer & Genomic Sciences, University of Birmingham, Edgbaston, UK
| | - Ahmed H A Khalaf
- School of Pharmacy, University of Nottingham, University Park, Nottingham, UK
| | - Alessandro Rettino
- School of Pharmacy, University of Nottingham, University Park, Nottingham, UK
| | - Jerome Xicluna
- School of Pharmacy, University of Nottingham, University Park, Nottingham, UK
| | - Laura Butler
- Institute of Cancer & Genomic Sciences, University of Birmingham, Edgbaston, UK
| | - Joanna R Morris
- Institute of Cancer & Genomic Sciences, University of Birmingham, Edgbaston, UK
| | - David M Heery
- School of Pharmacy, University of Nottingham, University Park, Nottingham, UK
| | - Nicole M Clarke
- School of Pharmacy, University of Nottingham, University Park, Nottingham, UK
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Ohsugi T, Yamaguchi K, Zhu C, Ikenoue T, Takane K, Shinozaki M, Tsurita G, Yano H, Furukawa Y. Anti-apoptotic effect by the suppression of IRF1 as a downstream of Wnt/β-catenin signaling in colorectal cancer cells. Oncogene 2019; 38:6051-6064. [PMID: 31292489 DOI: 10.1038/s41388-019-0856-9] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2018] [Revised: 02/27/2019] [Accepted: 04/16/2019] [Indexed: 12/29/2022]
Abstract
Impaired Wnt signaling pathway plays a crucial role in the development of colorectal cancer through activation of the β-catenin/TCF7L2 complex. Although genes upregulated by Wnt/β-catenin signaling have been intensively studied, the roles of downregulated genes are poorly understood. Previously, we reported that interferon-induced proteins with tetratricopeptide repeats 2 (IFIT2) was downregulated by the Wnt/β-catenin signaling, and that the suppressed expression of IFIT2 conferred antiapoptotic property to colorectal cancer (CRC) cells. However, the mechanisms underlying how Wnt/β-catenin signaling regulates IFIT2 remain to be elucidated. In this study, we have uncovered that the expression of IFIT2 is induced by IRF1, which is negatively regulated by the Wnt/β-catenin signaling. In addition, we found that downregulation of IRF1 is mediated by its degradation through the ubiquitination-proteasome pathway, and that decreased activity of a deubiquitinase complex containing USP1 and UAF1 is involved in the degradation of IRF1 by Wnt/β-catenin signaling. These data should provide better understanding of the Wnt signaling pathway and human carcinogenesis.
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Affiliation(s)
- Tomoyuki Ohsugi
- Division of Clinical Genome Research, Advanced Clinical Research Center, Institute of Medical Science, the University of Tokyo, Tokyo, 108-8639, Japan
| | - Kiyoshi Yamaguchi
- Division of Clinical Genome Research, Advanced Clinical Research Center, Institute of Medical Science, the University of Tokyo, Tokyo, 108-8639, Japan
| | - Chi Zhu
- Division of Clinical Genome Research, Advanced Clinical Research Center, Institute of Medical Science, the University of Tokyo, Tokyo, 108-8639, Japan
| | - Tsuneo Ikenoue
- Division of Clinical Genome Research, Advanced Clinical Research Center, Institute of Medical Science, the University of Tokyo, Tokyo, 108-8639, Japan
| | - Kiyoko Takane
- Division of Clinical Genome Research, Advanced Clinical Research Center, Institute of Medical Science, the University of Tokyo, Tokyo, 108-8639, Japan
| | - Masaru Shinozaki
- Department of Surgery, IMSUT Hospital, Institute of Medical Science, the University of Tokyo, Tokyo, 108-8639, Japan
| | - Giichiro Tsurita
- Department of Surgery, IMSUT Hospital, Institute of Medical Science, the University of Tokyo, Tokyo, 108-8639, Japan
| | - Hideaki Yano
- Department of Surgery, Center Hospital of the National Center for Global Health and Medicine, Tokyo, 162-8655, Japan
| | - Yoichi Furukawa
- Division of Clinical Genome Research, Advanced Clinical Research Center, Institute of Medical Science, the University of Tokyo, Tokyo, 108-8639, Japan.
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4
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Jiang L, Liu JY, Shi Y, Tang B, He T, Liu JJ, Fan JY, Wu B, Xu XH, Zhao YL, Qian F, Cui YH, Yu PW. MTMR2 promotes invasion and metastasis of gastric cancer via inactivating IFNγ/STAT1 signaling. JOURNAL OF EXPERIMENTAL & CLINICAL CANCER RESEARCH : CR 2019; 38:206. [PMID: 31113461 PMCID: PMC6528261 DOI: 10.1186/s13046-019-1186-z] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/11/2019] [Accepted: 04/22/2019] [Indexed: 12/24/2022]
Abstract
Background The aberrant expression of myotubularin-related protein 2 (MTMR2) has been found in some cancers, but little is known about the roles and clinical relevance. The present study aimed to investigate the roles and clinical relevance of MTMR2 as well as the underlying mechanisms in gastric cancer (GC). Methods MTMR2 expression was examined in 295 GC samples by using immunohistochemistry (IHC). The correlation between MTMR2 expression and clinicopathological features and outcomes of the patients was analyzed. The roles of MTMR2 in regulating the invasive and metastatic capabilities of GC cells were observed using gain-and loss-of-function assays both in vitro and in vivo. The pathways involved in MTMR2-regulating invasion and metastasis were selected and identified by using mRNA expression profiling. Functions and underlying mechanisms of MTMR2-mediated invasion and metastasis were further investigated in a series of in vitro studies. Results MTMR2 was highly expressed in human GC tissues compared to adjacent normal tissues and its expression levels were significantly correlated with depth of invasion, lymph node metastasis, and TNM stage. Patients with MTMR2high had significantly shorter lifespan than those with MTMR2low. Cox regression analysis showed that MTMR2 was an independent prognostic indicator for GC patients. Knockdown of MTMR2 significantly reduced migratory and invasive capabilities in vitro and metastases in vivo in GC cells, while overexpressing MTMR2 achieved the opposite results. MTMR2 knockdown and overexpression markedly inhibited and promoted the epithelial-mesenchymal transition (EMT), respectively. MTMR2 mediated EMT through the IFNγ/STAT1/IRF1 pathway to promote GC invasion and metastasis. Phosphorylation of STAT1 and IRF1 was increased by MTMR2 knockdown and decreased by MTMR2 overexpression accompanying with ZEB1 down-regulation and up-regulation, respectively. Silencing IRF1 upregulated ZEB1, which induced EMT and consequently enhanced invasion and metastasis in GC cells. Conclusions Our findings suggest that MTMR2 is an important promoter in GC invasion and metastasis by inactivating IFNγ/STAT1 signaling and may act as a new prognostic indicator and a potential therapeutic target for GC. Electronic supplementary material The online version of this article (10.1186/s13046-019-1186-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Lei Jiang
- Department of General Surgery and Center of Minimal Invasive Gastrointestinal Surgery, Southwest Hospital, Third Military Medical University (Army Medical University), No. 30 Gaotanyan Street, Chongqing, 400038, China
| | - Jun-Yan Liu
- Department of General Surgery and Center of Minimal Invasive Gastrointestinal Surgery, Southwest Hospital, Third Military Medical University (Army Medical University), No. 30 Gaotanyan Street, Chongqing, 400038, China
| | - Yan Shi
- Department of General Surgery and Center of Minimal Invasive Gastrointestinal Surgery, Southwest Hospital, Third Military Medical University (Army Medical University), No. 30 Gaotanyan Street, Chongqing, 400038, China
| | - Bo Tang
- Department of General Surgery and Center of Minimal Invasive Gastrointestinal Surgery, Southwest Hospital, Third Military Medical University (Army Medical University), No. 30 Gaotanyan Street, Chongqing, 400038, China
| | - Tao He
- Department of General Surgery and Center of Minimal Invasive Gastrointestinal Surgery, Southwest Hospital, Third Military Medical University (Army Medical University), No. 30 Gaotanyan Street, Chongqing, 400038, China
| | - Jia-Jia Liu
- Department of General Surgery and Center of Minimal Invasive Gastrointestinal Surgery, Southwest Hospital, Third Military Medical University (Army Medical University), No. 30 Gaotanyan Street, Chongqing, 400038, China
| | - Jun-Yan Fan
- Department of General Surgery and Center of Minimal Invasive Gastrointestinal Surgery, Southwest Hospital, Third Military Medical University (Army Medical University), No. 30 Gaotanyan Street, Chongqing, 400038, China
| | - Bin Wu
- Department of General Surgery and Center of Minimal Invasive Gastrointestinal Surgery, Southwest Hospital, Third Military Medical University (Army Medical University), No. 30 Gaotanyan Street, Chongqing, 400038, China
| | - Xian-Hui Xu
- Department of General Surgery and Center of Minimal Invasive Gastrointestinal Surgery, Southwest Hospital, Third Military Medical University (Army Medical University), No. 30 Gaotanyan Street, Chongqing, 400038, China
| | - Yong-Liang Zhao
- Department of General Surgery and Center of Minimal Invasive Gastrointestinal Surgery, Southwest Hospital, Third Military Medical University (Army Medical University), No. 30 Gaotanyan Street, Chongqing, 400038, China
| | - Feng Qian
- Department of General Surgery and Center of Minimal Invasive Gastrointestinal Surgery, Southwest Hospital, Third Military Medical University (Army Medical University), No. 30 Gaotanyan Street, Chongqing, 400038, China
| | - You-Hong Cui
- Department of General Surgery and Center of Minimal Invasive Gastrointestinal Surgery, Southwest Hospital, Third Military Medical University (Army Medical University), No. 30 Gaotanyan Street, Chongqing, 400038, China. .,Institute of Pathology and Southwest Cancer Center, and Key Laboratory of Tumor Immunopathology of Ministry of Education of China, Southwest Hospital, Third Military Medical University (Army Medical University), No. 30 Gaotanyan Street, Chongqing, 400038, China.
| | - Pei-Wu Yu
- Department of General Surgery and Center of Minimal Invasive Gastrointestinal Surgery, Southwest Hospital, Third Military Medical University (Army Medical University), No. 30 Gaotanyan Street, Chongqing, 400038, China.
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Identification of an IRF-1 splicing transcript in APL cells sharing similar transactivation activity of the full length one. Gene 2017; 605:108-113. [PMID: 28039033 DOI: 10.1016/j.gene.2016.12.029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2016] [Revised: 11/10/2016] [Accepted: 12/23/2016] [Indexed: 11/19/2022]
Abstract
Interferon regulatory factor-1 (IRF-1) is a member of the interferon regulatory factor family. It acts as a transcriptional activator and plays a critical role in antiviral defense, immune response, cell growth regulation, apoptosis and cell differentiation. Deletions, mutations or aberrant splicing of IRF-1 would result in its functional inactivation, and closely related to the tumorigenesis. In this work, we identified an IRF-1 splicing transcript (IRF-1-s) in all-trans retinoic acid (ATRA)-treated acute promyelocytic leukemia (APL) cell line NB4 cells. It lost the exon 8 and 9 of the full length IRF-1, expressed in numerous cell types and could be induced to expression by ATRA in NB4 cells. It turned out similar biological activity as full length IRF-1 to enhance the transcription of interferon stimulated response element (ISRE)-containing target genes. Identification of IRF-1-s in NB4 cells would be benefit for our further exploring the signaling pathway of ATRA and interferons, as well as the mechanisms of differentiation of APL cells.
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IRF1 Downregulation by Ras/MEK Is Independent of Translational Control of IRF1 mRNA. PLoS One 2016; 11:e0160529. [PMID: 27508303 PMCID: PMC4980046 DOI: 10.1371/journal.pone.0160529] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Accepted: 07/19/2016] [Indexed: 01/09/2023] Open
Abstract
Oncogenic activation of Ras/MEK downregulates the expression of interferon regulatory factor 1 (IRF1), which is a prerequisite for oncolytic viruses to replicate in cancer cells [1]. Moreover, restoration of IRF1 expression is essential to induce apoptosis of cancer cells treated with a MEK inhibitor [2]. However, the molecular mechanisms that underlie IRF1 downregulation by Ras/MEK remain unclear. In this study, we determined whether Ras/MEK activation modulates IRF1 expression at its translational level. MEK inhibition increased the activity of IRF1 promoter construct in Ras transformed NIH3T3 cells and wild type MEF, but not in IRF1 deficient MEF, indicating that IRF1 protein is required for the transcriptional activation of IRF1. By conducting reporter analysis using IRF1 5’- and 3’- UTR constructs, we determined that cis elements on 5’- and 3’-UTR of IRF1 mRNA are not involved in the IRF1 regulation by Ras/MEK. We further compared the recruitment of ribosomes to IRF1 mRNA in RasV12 cells treated with or without the MEK inhibitor by conducting polysome analysis. No difference was observed in the polysomal distribution of IRF1 mRNA between RasV12 cells treated with and without the MEK inhibitor. These results suggest that regulation of IRF1 translation is independent of IRF1 downregulation by Ras/MEK.
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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] [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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Schwartz-Roberts JL, Cook KL, Chen C, Shajahan-Haq AN, Axelrod M, Wärri A, Riggins RB, Jin L, Haddad BR, Kallakury BV, Baumann WT, Clarke R. Interferon regulatory factor-1 signaling regulates the switch between autophagy and apoptosis to determine breast cancer cell fate. Cancer Res 2015; 75:1046-55. [PMID: 25576084 PMCID: PMC4359953 DOI: 10.1158/0008-5472.can-14-1851] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Interferon regulatory factor-1 (IRF1) is a tumor suppressor that regulates cell fate in several cell types. Here, we report an inverse correlation in expression of nuclear IRF1 and the autophagy regulator ATG7 in human breast cancer cells that directly affects their cell fate. In mice harboring mutant Atg7, nuclear IRF1 was increased in mammary tumors, spleen, and kidney. Mechanistic investigations identified ATG7 and the cell death modulator beclin-1 (BECN1) as negative regulators of IRF1. Silencing ATG7 or BECN1 caused estrogen receptor-α to exit the nucleus at the time when IRF1 nuclear localization occurred. Conversely, silencing IRF1 promoted autophagy by increasing BECN1 and blunting IGF1 receptor and mTOR survival signaling. Loss of IRF1 promoted resistance to antiestrogens, whereas combined silencing of ATG7 and IRF1 restored sensitivity to these agents. Using a mathematical model to prompt signaling hypotheses, we developed evidence that ATG7 silencing could resensitize IRF1-attenuated cells to apoptosis through mechanisms that involve other estrogen-regulated genes. Overall, our work shows how inhibiting the autophagy proteins ATG7 and BECN1 can regulate IRF1-dependent and -independent signaling pathways in ways that engender a new therapeutic strategy to attack breast cancer.
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Affiliation(s)
- Jessica L Schwartz-Roberts
- Department of Physiology and Biophysics, Lombardi Comprehensive Cancer Center, Georgetown University, Washington, DC. Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University, Washington, DC
| | - Katherine L Cook
- Department of Physiology and Biophysics, Lombardi Comprehensive Cancer Center, Georgetown University, Washington, DC. Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University, Washington, DC
| | - Chun Chen
- Department of Biological Sciences, Virginia Polytechnic Institute and State University, Blacksburg, Virginia. Department of Electrical and Computer Engineering, Virginia Polytechnic Institute and State University, Blacksburg, Virginia
| | - Ayesha N Shajahan-Haq
- Department of Physiology and Biophysics, Lombardi Comprehensive Cancer Center, Georgetown University, Washington, DC. Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University, Washington, DC
| | - Margaret Axelrod
- Department of Physiology and Biophysics, Lombardi Comprehensive Cancer Center, Georgetown University, Washington, DC. Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University, Washington, DC
| | - Anni Wärri
- Department of Physiology and Biophysics, Lombardi Comprehensive Cancer Center, Georgetown University, Washington, DC. Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University, Washington, DC
| | - Rebecca B Riggins
- Department of Physiology and Biophysics, Lombardi Comprehensive Cancer Center, Georgetown University, Washington, DC. Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University, Washington, DC
| | - Lu Jin
- Department of Physiology and Biophysics, Lombardi Comprehensive Cancer Center, Georgetown University, Washington, DC. Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University, Washington, DC
| | - Bassem R Haddad
- Department of Physiology and Biophysics, Lombardi Comprehensive Cancer Center, Georgetown University, Washington, DC. Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University, Washington, DC
| | - Bhaskar V Kallakury
- Department of Pathology, Georgetown University Medical Center, Washington, DC
| | - William T Baumann
- Department of Biological Sciences, Virginia Polytechnic Institute and State University, Blacksburg, Virginia. Department of Electrical and Computer Engineering, Virginia Polytechnic Institute and State University, Blacksburg, Virginia
| | - Robert Clarke
- Department of Physiology and Biophysics, Lombardi Comprehensive Cancer Center, Georgetown University, Washington, DC. Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University, Washington, DC.
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AbuSara N, Razavi S, Derwish L, Komatsu Y, Licursi M, Hirasawa K. Restoration of IRF1-dependent anticancer effects by MEK inhibition in human cancer cells. Cancer Lett 2014; 357:575-81. [PMID: 25497010 DOI: 10.1016/j.canlet.2014.12.017] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2014] [Revised: 12/02/2014] [Accepted: 12/05/2014] [Indexed: 02/09/2023]
Abstract
Interferon regulatory factor (IRF1) is a potent antiviral, antitumor and immune regulatory protein. Recently, we found that activated Ras/MEK inhibits antiviral response by downregulating IRF1 expression and renders cancer cells susceptible to oncolytic viruses. In this study, we sought to determine whether IRF1 downregulation underlies oncogenesis induced by Ras/MEK activation in human cancer cells. Treatment of the MEK inhibitor U0126 promoted IRF1 expression in 7 of 11 cancer cell lines we tested. IRF1 promotion was also observed in human cancer cell lines treated with different MEK inhibitors or with RNAi oligonucleotides against extracellular signal-regulated kinases (ERKs). Restoration of the expression of antitumor genes, p27 and p53 upregulated modulator of apoptosis (PUMA), by MEK inhibition was less in IRF1 shRNA knockdown cancer cells than in vector control cancer cells, suggesting that Ras/MEK targets IRF1 for the downregulation of the antitumor genes. Moreover, apoptosis induction by U0126 was significantly reduced in IRF1 shRNA knockdown cells than vector control cells. This study demonstrates that IRF1 expression is suppressed by activated Ras/MEK in human cancer cells and that IRF1 plays essential roles in apoptosis induced by Ras/MEK inhibition.
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Affiliation(s)
- Nader AbuSara
- Division of BioMedical Sciences, Faculty of Medicine, Memorial University of Newfoundland, St. John's, Newfoundland, Canada
| | - Seyd Razavi
- Division of BioMedical Sciences, Faculty of Medicine, Memorial University of Newfoundland, St. John's, Newfoundland, Canada
| | - Leena Derwish
- Division of BioMedical Sciences, Faculty of Medicine, Memorial University of Newfoundland, St. John's, Newfoundland, Canada
| | - Yumiko Komatsu
- Division of BioMedical Sciences, Faculty of Medicine, Memorial University of Newfoundland, St. John's, Newfoundland, Canada
| | - Maria Licursi
- Division of BioMedical Sciences, Faculty of Medicine, Memorial University of Newfoundland, St. John's, Newfoundland, Canada
| | - Kensuke Hirasawa
- Division of BioMedical Sciences, Faculty of Medicine, Memorial University of Newfoundland, St. John's, Newfoundland, Canada.
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10
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Alanazi I, Ebrahimie E, Hoffmann P, Adelson DL. Combined gene expression and proteomic analysis of EGF induced apoptosis in A431 cells suggests multiple pathways trigger apoptosis. Apoptosis 2014; 18:1291-1305. [PMID: 23892916 DOI: 10.1007/s10495-013-0887-6] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
A431 cells, derived from epidermoid carcinoma, overexpress the epidermal growth factor receptor (EGFR) and when treated with a high dose of EGF will undergo apoptosis. We exploited microarray and proteomics techniques and network prediction to study the regulatory mechanisms of EGF-induced apoptosis in A431 cells. We observed significant changes in gene expression in 162 genes, approximately evenly split between pro-apoptotic and anti-apoptotic genes and identified 30 proteins from the proteomic data that had either pro or anti-apoptotic annotation. Our correlation analysis of gene expression and proteome modeled a number of distinct sub-networks that are associated with the onset of apoptosis, allowing us to identify specific pathways and components. These include components of the interferon signalling pathway, and down stream components, including cytokines and suppressors of cytokine signalling. A central component of almost all gene expression sub-networks identified was TP53, which is mutated in A431 cells, and was down regulated. This down regulation of TP53 appeared to be correlated with proteomic sub-networks of cytoskeletal or cell adhesion components that might induce apoptosis by triggering cytochrome C release. Of the only three genes also differentially expressed as proteins, only serpinb1 had a known association with apoptosis. We confirmed that up regulation and cleavage of serpinb1 into L-DNAaseII was correlated with the induction of apoptosis. It is unlikely that a single pathway, but more likely a combination of pathways is needed to trigger EGF induced apoptosis in A431cells.
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Affiliation(s)
- Ibrahim Alanazi
- School of Molecular & Biomedical Science, The University of Adelaide, Adelaide, SA, Australia
| | - Esmaeil Ebrahimie
- School of Molecular & Biomedical Science, The University of Adelaide, Adelaide, SA, Australia
| | - Peter Hoffmann
- School of Molecular & Biomedical Science, The University of Adelaide, Adelaide, SA, Australia
| | - David L Adelson
- School of Molecular & Biomedical Science, The University of Adelaide, Adelaide, SA, Australia.
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Lindahl GE, Stock CJ, Shi-Wen X, Leoni P, Sestini P, Howat SL, Bou-Gharios G, Nicholson AG, Denton CP, Grutters JC, Maher TM, Wells AU, Abraham DJ, Renzoni EA. Microarray profiling reveals suppressed interferon stimulated gene program in fibroblasts from scleroderma-associated interstitial lung disease. Respir Res 2013; 14:80. [PMID: 23915349 PMCID: PMC3750263 DOI: 10.1186/1465-9921-14-80] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2012] [Accepted: 07/25/2013] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Interstitial lung disease is a major cause of morbidity and mortality in systemic sclerosis (SSc), with insufficiently effective treatment options. Progression of pulmonary fibrosis involves expanding populations of fibroblasts, and the accumulation of extracellular matrix proteins. Characterisation of SSc lung fibroblast gene expression profiles underlying the fibrotic cell phenotype could enable a better understanding of the processes leading to the progressive build-up of scar tissue in the lungs. In this study we evaluate the transcriptomes of fibroblasts isolated from SSc lung biopsies at the time of diagnosis, compared with those from control lungs. METHODS We used Affymetrix oligonucleotide microarrays to compare the gene expression profile of pulmonary fibroblasts cultured from 8 patients with pulmonary fibrosis associated with SSc (SSc-ILD), with those from control lung tissue peripheral to resected cancer (n=10). Fibroblast cultures from 3 patients with idiopathic pulmonary fibrosis (IPF) were included as a further comparison. Genes differentially expressed were identified using two separate analysis programs following a set of pre-determined criteria: only genes significant in both analyses were considered. Microarray expression data was verified by qRT-PCR and/or western blot analysis. RESULTS A total of 843 genes were identified as differentially expressed in pulmonary fibroblasts from SSc-ILD and/or IPF compared to control lung, with a large overlap in the expression profiles of both diseases. We observed increased expression of a TGF-β response signature including fibrosis associated genes and myofibroblast markers, with marked heterogeneity across samples. Strongly suppressed expression of interferon stimulated genes, including antiviral, chemokine, and MHC class 1 genes, was uniformly observed in fibrotic fibroblasts. This expression profile includes key regulators and mediators of the interferon response, such as STAT1, and CXCL10, and was also independent of disease group. CONCLUSIONS This study identified a strongly suppressed interferon-stimulated gene program in fibroblasts from fibrotic lung. The data suggests that the repressed expression of interferon-stimulated genes may underpin critical aspects of the profibrotic fibroblast phenotype, identifying an area in pulmonary fibrosis that requires further investigation.
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Affiliation(s)
- Gisela E Lindahl
- Interstitial Lung Disease Unit, Royal Brompton Hospital and National Heart and Lung Institute, Imperial College London, Emmanuel Kaye Building, 1B Manresa Road, London SW3 6LR, UK.
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12
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Pavan S, Olivero M, Corà D, Di Renzo MF. IRF-1 expression is induced by cisplatin in ovarian cancer cells and limits drug effectiveness. Eur J Cancer 2013; 49:964-73. [DOI: 10.1016/j.ejca.2012.09.024] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2012] [Revised: 09/11/2012] [Accepted: 09/15/2012] [Indexed: 10/27/2022]
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Rettino A, Clarke NM. Genome-wide Identification of IRF1 Binding Sites Reveals Extensive Occupancy at Cell Death Associated Genes. ACTA ACUST UNITED AC 2013. [PMID: 25893139 PMCID: PMC4398980 DOI: 10.4172/2157-2518.s6-009] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
IRF1 is a transcription factor involved in interferon signaling and has been shown to harbor tumor suppressor activity. In order to comprehensively identify pathways regulated by IRF1, we used chromatin immunoprecipitation followed by massive-parallel sequencing (ChIP-seq) to evaluate the gene targets of IRF1 genome-wide. We identified 17,416 total binding events in breast cancer cells. Functional categorization of the binding sites after IFN-gamma (interferon-gamma) treatment determined that ‘apoptosis’ or ‘cell death’ is the most enriched target process. Motif discovery analysis of the chromosomal regions bound by IRF1 identified a number of unique motifs correlated with apoptosis, DNA damage and immune processes. Analysis of GEO transcriptome data from IRF1-transduced cells or IFN-gamma treated fibroblasts indicates that IRF1-bound targets in IFN-treated cells are associated with a positive transcriptional response. Many of the enriched target genes from the expression analysis are associated with apoptosis. Importantly, this data indicates that a significant function of IRF1 is the regulation of anti-cancer apoptotic pathways and this reinforces IRF1’s role as a tumor suppressor.
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Affiliation(s)
- Alessandro Rettino
- School of Pharmacy, Centre for Biomolecular Sciences, University of Nottingham, Nottingham, NG7 2RD, UK
| | - Nicole M Clarke
- School of Pharmacy, Centre for Biomolecular Sciences, University of Nottingham, Nottingham, NG7 2RD, UK
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14
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Function and mechanism by which interferon regulatory factor-1 inhibits oncogenesis. Oncol Lett 2012; 5:417-423. [PMID: 23420765 PMCID: PMC3573131 DOI: 10.3892/ol.2012.1051] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2012] [Accepted: 10/24/2012] [Indexed: 01/26/2023] Open
Abstract
The present review focuses on recent advances in the understanding of the molecular mechnisms by which interferon regulatory factor (IRF)-1 inhibits oncogenesis. IRF-1 is associated with regulation of interferon α and β transcription. In addition, numerous clinical studies have indicated that IRF-1 gene deletion or rearrangement correlates with development of specific forms of human cancer. IRF-1 has been revealed to exhibit marked functional diversity in the regulation of oncogenesis. IRF-1 activates a set of target genes associated with regulation of the cell cycle, apoptosis and the immune response. The role of IRF-1 in the regulation of various types of human tumor has important implications for understanding the susceptibility and progression of cancer. In addition, an improved understanding of the role of IRF-1 in the pathological processes that lead to human malignant diseases may aid development of novel therapeutic strategies.
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15
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Yi Y, Wu H, Gao Q, He HW, Li YW, Cai XY, Wang JX, Zhou J, Cheng YF, Jin JJ, Fan J, Qiu SJ. Interferon regulatory factor (IRF)-1 and IRF-2 are associated with prognosis and tumor invasion in HCC. Ann Surg Oncol 2012; 20:267-76. [PMID: 22805863 DOI: 10.1245/s10434-012-2487-z] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2012] [Indexed: 12/27/2022]
Abstract
BACKGROUND Interferon regulatory factor (IRF)-1 and IRF-2 are transcriptional factors that mediate interferons functions; the loss of IRF-1 expression and gain of IRF-2 expression were associated with malignant phenotype in multiple cancers. However, their roles in the progression of hepatocellular carcinoma (HCC) remain poorly described. METHODS Immunohistochemistry was used to analyze the nuclear expression of IRF-1/2 in a cohort of 332 HCC patients. The expression of IRF-1/2 in HCC cell lines with stepwise metastasis potential was determined by immunoblotting. Downregulation of IRF-1 or IRF-2 expression was mediated by shRNAs; a series of experiments were conducted to determine the changes of invasion ability and downstream molecular events. RESULTS High expression of IRF-1 was associated with good outcome (p<.001 for OS/TTR), while high expression of IRF-2 was relevant to increased recurrence probability (p=.049) in HCC patients. The combination of the 2 IRFs showed better predictive power than either factor alone. Immunoblotting analysis revealed that IRF-2/IRF-1 ratio was positively correlated with the metastatic potential in human HCC cell lines. Downregulation of IRF-2 led to sharply attenuated invasion ability, paralleled with a decreased expression of STAT3, p-STAT3(Ser727), and MMP9. While downregulation of IRF-1 caused a concurrent decrease in IRF-2, little or no change was displayed in IRF-2/IRF-1 ratio, invasion ability, and MMP9 expression. CONCLUSIONS IRF-1 and IRF-2 expression were associated with prognosis of HCC patients with opposite predictive power. IRF-2/IRF-1 ratio was associated with tumor invasion, probably through modulation of MMP9 expression mediated by STAT3.
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Affiliation(s)
- Yong Yi
- Key Laboratory for Carcinogenesis & Cancer Invasion, Liver Cancer Institute, Zhongshan Hospital, Fudan University, The Chinese Ministry of Education, Shanghai, People's Republic of China
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16
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Ksienzyk A, Neumann B, Nandakumar R, Finsterbusch K, Grashoff M, Zawatzky R, Bernhardt G, Hauser H, Kröger A. IRF-1 expression is essential for natural killer cells to suppress metastasis. Cancer Res 2011; 71:6410-8. [PMID: 21900395 DOI: 10.1158/0008-5472.can-11-1565] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
IFN-γ promotes tumoral immune surveillance, but its involvement in controlling metastases is less clear. Using a mouse model of pulmonary metastases, we show that local IFN-γ treatment inhibits formation of metastases through its regulation of IRF-1 in tumor cells. IRF-1 is an IFN-γ-induced transcription factor pivotal in the regulation of infection and inflammation. IRF-1 blockade abolished the inhibitory effect of IFN-γ on tumor metastases, whereas ectopic expression of IRF-1 phenocopied the inhibitory effects of IFN-γ. IRF-1 did not affect the survival of tumor cells in the circulation or their infiltration into lungs, but it was essential to support the pulmonary attraction and activation of natural killer (NK) cells. Depleting NK cells from mice abolished the protective effect of IFN-γ or IRF-1 on metastases. In addition, cytotoxicity assays revealed that tumor cells expressing IRF-1 were targeted more effectively by NK cells than IRF-1 nonexpressing tumor cells. Moreover, NK cells isolated from lungs inoculated with IRF-1-expressing tumor cells exhibit a greater cytotoxic activity. Mechanistic investigations revealed that IRF-1-induced NK cell cytotoxicity was independent of perforin and granzyme B but dependent on the NK cell activating receptor DNAM-1. Taken together, our findings establish IRF-1 as an essential mediator of the cross-talk between tumor cells and NK cells that mediate immune surveillance in the metastatic niche.
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Affiliation(s)
- Antje Ksienzyk
- Department of Gene Regulation and Differentiation, Helmholtz Centre for Infection Research, Braunschweig, Germany
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Gao J, Wang Y, Xing Q, Yan J, Senthil M, Akmal Y, Kowolik CM, Kang J, Lu DM, Zhao M, Lin Z, Cheng CHK, Yip MLR, Yim JH. Identification of a natural compound by cell-based screening that enhances interferon regulatory factor-1 activity and causes tumor suppression. Mol Cancer Ther 2011; 10:1774-83. [PMID: 21817116 DOI: 10.1158/1535-7163.mct-11-0304] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The transcription factor interferon regulatory factor-1 (IRF-1) is induced by many tumor-suppressive stimuli and can mediate antiproliferative and proapoptotic effects in cancer cells. Thus, identifying agents that enhance IRF-1 activity may be an effective approach to cancer therapy. A cell-based screening assay was developed to identify extracts and compounds that could enhance IRF-1 activity, using an IRF-1-dependent luciferase reporter cell line. Through this approach, we identified a natural product extract and a known active component of this extract, baicalein, which causes a marked increase in IRF-1-dependent reporter gene expression and IRF-1 protein, with modulation of known IRF-1 targets PUMA and cyclin D1. Baicalein causes suppression of growth in vitro in multiple cancer cell lines in the low micromolar range. IRF-1 plays a role in this growth suppression as shown by significant resistance to growth suppression in a breast cancer cell line stably transfected with short hairpin RNA against IRF-1. Finally, intraperitoneal administration of baicalein by repeated injection causes inhibition of growth in both xenogeneic and syngeneic mouse models of cancer without toxicity to the animals. These findings indicate that identifying enhancers of IRF-1 activity may have utility in anticancer therapies and that cell-based screening for activation of transcription factors can be a useful approach for drug discovery.
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Affiliation(s)
- Jinbo Gao
- Department of Surgery, Union Hospital, Huazhong University of Science and Technology, Wuhan, Hubei, PR China
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Shi L, Perin JC, Leipzig J, Zhang Z, Sullivan KE. Genome-wide analysis of interferon regulatory factor I binding in primary human monocytes. Gene 2011; 487:21-8. [PMID: 21803131 DOI: 10.1016/j.gene.2011.07.004] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2011] [Accepted: 07/09/2011] [Indexed: 01/09/2023]
Abstract
IRF1 is a transcription factor that participates in interferon signaling. Previous studies of IRF1 binding have utilized in vitro assays. We used ChIP-seq in human monocytes to better define the recognition motif for IRF1. The newly identified 18bp motif (RAAASNGAAAGTGAAASY) is a refinement of the 13bp IRF1 motif commonly used. We utilized the 18bp consensus motif and identified 345 potential target genes. To compare the 18bp motif with the 13bp motif, we compared putative gene targets. Only 56 potential gene targets were defined by both consensus motifs. To compare biological effects of interferon on the 13bp and the 18bp consensus targets, we mined expression data from cells exposed to interferons or transfected with IRF1. In all cases, the 18bp consensus motif was more strongly associated with transcriptional responses than the 13bp motif. Therefore, the new 18bp consensus motif appears to have a greater association with biological activities of IRF1.
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Affiliation(s)
- Lihua Shi
- Department of Pediatrics, The Children's Hospital of Philadelphia, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA
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19
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Balasubramanian S, Fan M, Messmer-Blust AF, Yang CH, Trendel JA, Jeyaratnam JA, Pfeffer LM, Vestal DJ. The interferon-gamma-induced GTPase, mGBP-2, inhibits tumor necrosis factor alpha (TNF-alpha) induction of matrix metalloproteinase-9 (MMP-9) by inhibiting NF-kappaB and Rac protein. J Biol Chem 2011; 286:20054-64. [PMID: 21502320 PMCID: PMC3103378 DOI: 10.1074/jbc.m111.249326] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2011] [Revised: 04/15/2011] [Indexed: 11/06/2022] Open
Abstract
Matrix metalloproteinase-9 (MMP-9) is important in numerous normal and pathological processes, including the angiogenic switch during tumor development and tumor metastasis. Whereas TNF-α and other cytokines up-regulate MMP-9 expression, interferons (IFNs) inhibit MMP-9 expression. We found that IFN-γ treatment or forced expression of the IFN-induced GTPase, mGBP-2, inhibit TNF-α-induced MMP-9 expression in NIH 3T3 fibroblasts, by inhibiting MMP-9 transcription. The NF-κB transcription factor is required for full induction of MMP-9 by TNF-α. Both IFN-γ and mGBP-2 inhibit the transcription of a NF-κB-dependent reporter construct, suggesting that mGBP-2 inhibits MMP-9 induction via inhibition of NF-κB-mediated transcription. Interestingly, mGBP-2 does not inhibit TNF-α-induced degradation of IκBα or p65/RelA translocation into the nucleus. However, mGBP-2 inhibits p65 binding to a κB oligonucleotide probe in gel shift assays and to the MMP-9 promoter in chromatin immunoprecipitation assays. In addition, TNF-α activation of NF-κB in NIH 3T3 cells is dependent on Rac activation, as evidenced by the inhibition of TNF-α induction of NF-κB-mediated transcription by a dominant inhibitory form of Rac1. A role for Rac in the inhibitory action of mGBP-2 on NF-κB is further shown by the findings that mGBP-2 inhibits TNF-α activation of endogenous Rac and constitutively activate Rac can restore NF-κB transcription in the presence of mGBP-2. This is a novel mechanism by which IFNs can inhibit the cytokine induction of MMP-9 expression.
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Affiliation(s)
- Sujata Balasubramanian
- From the Department of Biological Sciences, University of Toledo, Toledo, Ohio 43606 and
| | - Meiyun Fan
- the Department of Pathology, University of Tennessee Health Science Center, Memphis, Tennessee 38163
| | | | - Chuan H. Yang
- the Department of Pathology, University of Tennessee Health Science Center, Memphis, Tennessee 38163
| | - Jill A. Trendel
- From the Department of Biological Sciences, University of Toledo, Toledo, Ohio 43606 and
| | - Jonathan A. Jeyaratnam
- From the Department of Biological Sciences, University of Toledo, Toledo, Ohio 43606 and
| | - Lawrence M. Pfeffer
- the Department of Pathology, University of Tennessee Health Science Center, Memphis, Tennessee 38163
| | - Deborah J. Vestal
- From the Department of Biological Sciences, University of Toledo, Toledo, Ohio 43606 and
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20
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Joshi S, Sharma B, Kaur S, Majchrzak B, Ueda T, Fukunaga R, Verma AK, Fish EN, Platanias LC. Essential role for Mnk kinases in type II interferon (IFNgamma) signaling and its suppressive effects on normal hematopoiesis. J Biol Chem 2011; 286:6017-26. [PMID: 21149447 PMCID: PMC3057839 DOI: 10.1074/jbc.m110.197921] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2010] [Revised: 12/10/2010] [Indexed: 12/22/2022] Open
Abstract
IFNγ exhibits potent antitumor effects and plays important roles in the innate immunity against cancer. However, the mechanisms accounting for the antiproliferative effects of IFNγ still remain to be elucidated. We examined the role of Mnk1 (MAPK-interacting protein kinase 1) in IFNγ signaling. Our data demonstrate that IFNγ treatment of sensitive cells results in engagement of Mnk1, activation of its kinase domain, and downstream phosphorylation of the cap-binding protein eIF4E on Ser-209. Such engagement of Mnk1 plays an important role in IFNγ-induced IRF-1 (IFN regulatory factor 1) gene mRNA translation/protein expression and is essential for generation of antiproliferative responses. In studies aimed to determine the role of Mnk1 in the induction of the suppressive effects of IFNs on primitive hematopoietic progenitors, we found that siRNA-mediated Mnk1/2 knockdown results in partial reversal of the suppressive effects of IFNγ on human CD34+-derived myeloid (CFU-GM) and erythroid (BFU-E) progenitors. These findings establish a key role for the Mnk/eIF4E pathway in the regulatory effects of IFNγ on normal hematopoiesis and identify Mnk kinases as important elements in the control of IFNγ-inducible ISG mRNA translation.
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Affiliation(s)
- Sonali Joshi
- From the Robert H. Lurie Comprehensive Cancer Center and Division of Hematology-Oncology, Northwestern University Medical School and Jesse Brown Veterans Affairs Medical Center, Chicago, Illinois 60611
| | - Bhumika Sharma
- From the Robert H. Lurie Comprehensive Cancer Center and Division of Hematology-Oncology, Northwestern University Medical School and Jesse Brown Veterans Affairs Medical Center, Chicago, Illinois 60611
| | - Surinder Kaur
- From the Robert H. Lurie Comprehensive Cancer Center and Division of Hematology-Oncology, Northwestern University Medical School and Jesse Brown Veterans Affairs Medical Center, Chicago, Illinois 60611
| | - Beata Majchrzak
- the Division of Cell and Molecular Biology, Toronto Research Institute, University Health Network and Department of Immunology, University of Toronto, Toronto, Ontario M5G2M1, Canada
| | - Takeshi Ueda
- the Department of Disease Model, Research Institute for Radiation Biology and Medicine, Hiroshima University, Hiroshima, 737-8553 Japan
| | - Rikiro Fukunaga
- the Department of Medical Chemistry, Graduate School of Medicine, Kyoto University, Kyoto 606-8501, Japan, and
| | - Amit K. Verma
- the Division of Hematology-Oncology, Department of Medicine, Albert Einstein College of Medicine, Bronx, New York 10461
| | - Eleanor N. Fish
- the Division of Cell and Molecular Biology, Toronto Research Institute, University Health Network and Department of Immunology, University of Toronto, Toronto, Ontario M5G2M1, Canada
| | - Leonidas C. Platanias
- From the Robert H. Lurie Comprehensive Cancer Center and Division of Hematology-Oncology, Northwestern University Medical School and Jesse Brown Veterans Affairs Medical Center, Chicago, Illinois 60611
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Stirnweiss A, Ksienzyk A, Klages K, Rand U, Grashoff M, Hauser H, Kröger A. IFN Regulatory Factor-1 Bypasses IFN-Mediated Antiviral Effects through Viperin Gene Induction. THE JOURNAL OF IMMUNOLOGY 2010; 184:5179-85. [DOI: 10.4049/jimmunol.0902264] [Citation(s) in RCA: 98] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Shultz DB, Rani MRS, Fuller JD, Ransohoff RM, Stark GR. Roles of IKK-beta, IRF1, and p65 in the activation of chemokine genes by interferon-gamma. J Interferon Cytokine Res 2010; 29:817-24. [PMID: 19929594 DOI: 10.1089/jir.2009.0034] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Activation of chemokine genes in response to interferon (IFN)-gamma or NF-kappaB is an important aspect of inflammation. Using the chemokine gene ip-10 in mouse embryonic fibroblast cells as an example, we show that the response to IFN-gamma is long lasting but secondary: initial STAT1 activation drives IRF1 synthesis, and IRF1 then binds to IFN-stimulated regulatory elements (ISREs) in the ip-10 promoter. The promoters of most IKK-beta-dependent IFN-stimulated genes (ISGs) also contain ISREs. In response to IFN-gamma, inhibitor of NF-kappaB (IkappaB) kinase beta (IKK-beta) is required to activate both newly synthesized IRF1 and the p65 subunit of NF-kappaB, which contributes to ip-10 expression by binding to kappaB sites in the ip-10 promoter, with little or no activation of classical NF-kappaB. In contrast to IFN-gamma, IL-1beta induces ip-10 expression rapidly but transiently, by activating classical NF-kappaB and increasing the synthesis of IRF1. Together, IL-1beta and IFN-gamma induce ip-10 synergistically. IFN-gamma does not affect the transient activation of classical NF-kappaB by IL-1beta and synergistic induction of ip-10 expression by IFN-gamma and IL-1beta occurs even after the activation of classical NF-kappaB has returned to basal levels. Therefore, IKK-beta has a novel role in IFN-gamma-dependent activation of chemokine gene expression through its activation of IRF1 and p65.
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Affiliation(s)
- David B Shultz
- Department of Molecular Genetics, Cleveland Clinic, Cleveland, Ohio 44195, USA
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Schlee M, Schuhmacher M, Hölzel M, Laux G, Bornkamm GW. c-MYC impairs immunogenicity of human B cells. Adv Cancer Res 2009; 97:167-88. [PMID: 17419945 DOI: 10.1016/s0065-230x(06)97007-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Deregulation of c-myc expression through chromosomal translocation is essential in the pathogenesis of Burkitt's lymphoma (BL). A characteristic feature of BL cells, compared to Epstein-Barr Virus (EBV)-immortalized B cells, is their lack of immunogenicity. To study the contribution of EBV genes and of the c-MYC protein to this phenotype, we have generated a conditional B cell system in which the viral proliferation program and expression of c-myc can be regulated independently of each other. In cells proliferating due to exogenous c-myc overexpression, the cell surface phenotype, the pattern of proliferation in single cell suspension, and the immunological characteristics of BL cells could be completely recapitulated. Yet, it had remained open whether nonimmunogenicity is the default phenotype when EBNA2 and LMP1 are switched off, or whether c-MYC actively contributes to immunosuppression. We provide evidence also for the latter by showing that c-MYC down-regulates genes of the NF-kappaB and interferon pathway in a dose-dependent fashion. c-MYC acts at at least two different levels, the level of interferon induction as well as at the level of action of type I and type II interferons on their respective target promoters. c-MYC does not block the interferon pathway completely, it shifts the balance and increases the threshold of interferon induction and action.
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Affiliation(s)
- Martin Schlee
- Institute of Clinical Molecular Biology and Tumor Genetics, GSF-National Research Center for Environment and Health, D-81377 München, Germany
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24
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Frontini M, Vijayakumar M, Garvin A, Clarke N. A ChIP-chip approach reveals a novel role for transcription factor IRF1 in the DNA damage response. Nucleic Acids Res 2009; 37:1073-85. [PMID: 19129219 PMCID: PMC2651779 DOI: 10.1093/nar/gkn1051] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
IRF1 is a transcription factor that regulates key processes in the immune system and in tumour suppression. To gain further insight into IRF1's role in these processes, we searched for new target genes by performing chromatin immunoprecipitation coupled to a CpG island microarray (ChIP–chip). Using this approach we identified 202 new IRF1-binding sites with high confidence. Functional categorization of the target genes revealed a surprising cadre of new roles that can be linked to IRF1. One of the major functional categories was the DNA damage response pathway. In order to further validate our findings, we show that IRF1 can regulate the mRNA expression of a number of the DNA damage response genes in our list. In particular, we demonstrate that the mRNA and protein levels of the DNA repair protein BRIP1 [Fanconi anemia gene J (FANC J)] are upregulated after IRF1 over-expression. We also demonstrate that knockdown of IRF1 by siRNA results in loss of BRIP1 expression, abrogation of BRIP1 foci after DNA interstrand crosslink (ICL) damage and hypersensitivity to the DNA crosslinking agent, melphalan; a characteristic phenotype of FANC J cells. Taken together, our data provides a more complete understanding of the regulatory networks controlled by IRF1 and reveals a novel role for IRF1 in regulating the ICL DNA damage response.
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Affiliation(s)
- Mattia Frontini
- MRC Clinical Sciences Centre, Faculty of Medicine Imperial College London, Hammersmith Hospital Campus, Du Cane Road, London, W12 0NN, UK
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25
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Wang J, Zhang W, Zhang Y, Chen Y, Zou B, Jiang B, Pang R, Gu Q, Qiao L, Lan H, Kung HF, Wong BCY. c-Jun N-terminal kinase (JNK1) upregulates XIAP-associated factor 1 (XAF1) through interferon regulatory factor 1 (IRF-1) in gastrointestinal cancer. Carcinogenesis 2008; 30:222-9. [PMID: 19056926 DOI: 10.1093/carcin/bgn271] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND AND AIMS X-linked inhibitor of apoptosis protein-associated factor 1 (XAF1) is a tumor suppressor that can sensitize cancer cell to apoptosis. Intrinsic expression of XAF1 in cancer cell is low. Our purpose is to determine the effect of c-Jun N-terminal kinase 1 (JNK1) on XAF1 expression and the putative mechanism. METHODS XAF1 expression in gastrointestinal (GI) cancer cell line AGS and SW1116 was detected by reverse transcription-polymerase chain reaction (PCR), real-time PCR and immunoblotting. The role of JNK1 was assessed by ectopic overexpression with wild-type (JNK1-WT) and dominant-negative (JNK1-DN) JNK1 constructs. The effects of JNK1 activator, interferon (IFN)-alpha, tumor necrosis factor (TNF)-alpha and phorbol-12-myristate-13-acetate (PMA), or JNK1 inhibitor, SP600125, were evaluated. An XAF1 promoter reporter pLUC107 with WT or mutated interferon regulatory factor 1-binding element (IRF-E) was used to assess JNK1-induced transcription by dual luciferase assay. RESULT Ectopic overexpression of JNK1-WT or treatment with IFN-alpha, TNF-alpha and PMA induced whereas SP600125 suppressed intrinsic and induced XAF1 expression. Induction of XAF1 required de novo protein synthesis. Moreover, JNK1 stimulated whereas SP600125 suppressed XAF1 promoter activity. JNK1 stimulated interferon regulatory factor 1 (IRF-1) expression, whereas both IRF-1 small-interfering RNA and site mutation of IRF-E within XAF1 promoter abrogated the effect of JNK1. CONCLUSION JNK1 stimulated and mediated the effects of IFN and TNF-alpha on XAF1 expression through transcriptional regulation by induction of IRF-1. The linkage of JNK1, IRF-1 and XAF1 in the same signal pathway may unravel a novel mechanism in regulation of apoptosis and differentiation of GI cancers.
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Affiliation(s)
- Jide Wang
- Department of Digestive Medicine, Nanfang Hospital, Southern Medical University, Guangzhou, China.
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Liu Y, Xiao H, Tian Y, Nekrasova T, Hao X, Lee HJ, Suh N, Yang CS, Minden A. The pak4 protein kinase plays a key role in cell survival and tumorigenesis in athymic mice. Mol Cancer Res 2008; 6:1215-24. [PMID: 18644984 DOI: 10.1158/1541-7786.mcr-08-0087] [Citation(s) in RCA: 113] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Pak4 is a member of the B group of p21-activated (Pak) kinases, originally identified as an effector protein for Cdc42. Although Pak4 is expressed at low levels in most adult tissues, it is highly overexpressed in tumor cell lines. Here, we show that Pak4 is also overexpressed in primary tumors, including colon, esophageal, and mammary tumors. Overexpression of Pak4 also leads to tumor formation in athymic mice, whereas deletion of Pak4 inhibits tumorigenesis. Although a constitutively active Pak4 mutant was previously shown to promote oncogenic transformation in cultured cells, our results are the first to show that Pak4 also promotes tumorigenesis in experimental animals. Furthermore, these results show for the first time that not only constitutively active Pak4, but also wild-type Pak4, is transforming, when experimental animals are used. These results are highly significant because wild-type Pak4, rather than activated Pak4, is overexpressed in tumor cells. Our results suggest that overexpression or activation of Pak4 is a key step in oncogenic transformation, due to its ability to promote cell survival and subsequent uncontrolled proliferation. The finding that Pak4 is up-regulated in so many types of cancers indicates that Pak4 may play a vital role in a wide range of different types of cancer. This makes it an attractive candidate for drug therapy for different types of cancer.
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Affiliation(s)
- Yingying Liu
- Department of Chemical Biology, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA
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27
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Tamura T, Yanai H, Savitsky D, Taniguchi T. The IRF family transcription factors in immunity and oncogenesis. Annu Rev Immunol 2008; 26:535-84. [PMID: 18303999 DOI: 10.1146/annurev.immunol.26.021607.090400] [Citation(s) in RCA: 957] [Impact Index Per Article: 59.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The interferon regulatory factor (IRF) family, consisting of nine members in mammals, was identified in the late 1980s in the context of research into the type I interferon system. Subsequent studies over the past two decades have revealed the versatile and critical functions performed by this transcription factor family. Indeed, many IRF members play central roles in the cellular differentiation of hematopoietic cells and in the regulation of gene expression in response to pathogen-derived danger signals. In particular, the advances made in understanding the immunobiology of Toll-like and other pattern-recognition receptors have recently generated new momentum for the study of IRFs. Moreover, the role of several IRF family members in the regulation of the cell cycle and apoptosis has important implications for understanding susceptibility to and progression of several cancers.
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Affiliation(s)
- Tomohiko Tamura
- Department of Immunology, Graduate School of Medicine and Faculty of Medicine, University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-0033, Japan
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28
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Takaoka A, Tamura T, Taniguchi T. Interferon regulatory factor family of transcription factors and regulation of oncogenesis. Cancer Sci 2008; 99:467-78. [PMID: 18190617 PMCID: PMC11159419 DOI: 10.1111/j.1349-7006.2007.00720.x] [Citation(s) in RCA: 115] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2007] [Revised: 11/21/2007] [Accepted: 11/25/2007] [Indexed: 01/03/2023] Open
Abstract
A family of transcription factors, the interferon regulatory factors (IRF), was identified originally in the context of the regulation of the type I interferon (IFN)-alpha/beta system. The IRF family has now expanded to nine members, and gene-disruption studies have revealed the critical involvement of these members in multiple facets of host defense systems, such as innate and adaptive immune responses and tumor suppression. In the present review article, we aim at summarizing our current knowledge of the roles of IRF in host defense, with special emphasis on their involvement in the regulation of oncogenesis.
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Affiliation(s)
- Akinori Takaoka
- Department of Immunology, Graduate School of Medicine and Faculty of Medicine, University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-0033, Japan
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29
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Interferon regulatory factor 6 promotes cell cycle arrest and is regulated by the proteasome in a cell cycle-dependent manner. Mol Cell Biol 2008; 28:2235-43. [PMID: 18212048 DOI: 10.1128/mcb.01866-07] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Interferon regulatory factor 6 (IRF6) is a novel and unique member of the IRF family of transcription factors. IRF6 has not been linked to the regulatory pathways or functions associated with other IRF family members, and the regulation and function of IRF6 remain unknown. We recently identified a protein interaction between IRF6 and the tumor suppressor maspin. To gain insight into the biological significance of the maspin-IRF6 interaction, we examined the regulation and function of IRF6 in relation to maspin in normal mammary epithelial cells. Our results demonstrate that in quiescent cells, IRF6 exists primarily in a nonphosphorylated state. However, cellular proliferation leads to rapid IRF6 phosphorylation, resulting in proteasome-dependent IRF6 degradation. These data are supported in situ by the increased expression of IRF6 in quiescent, differentiated lobuloalveolar cells of the lactating mammary gland compared to its expression in proliferating ductal and glandular epithelial cells during pregnancy. Furthermore, the reexpression of IRF6 in breast cancer cells results in cell cycle arrest, and the presence of maspin augments this response. These data support a model in which IRF6, in collaboration with maspin, promotes mammary epithelial cell differentiation by facilitating entry into the G(0) phase of the cell cycle.
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30
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Su ZZ, Sarkar D, Emdad L, Barral PM, Fisher PB. Central role of interferon regulatory factor-1 (IRF-1) in controlling retinoic acid inducible gene-I (RIG-I) expression. J Cell Physiol 2007; 213:502-10. [PMID: 17516545 DOI: 10.1002/jcp.21128] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Retinoic acid inducible gene-I (RIG-I) functions as the first line of defense against viral infection by sensing dsRNA and inducing type I interferon (IFN) production. The expression of RIG-I itself is induced by IFN-alpha/beta and dsRNA. To comprehend the molecular mechanism of expression regulation, we cloned the RIG-I promoter and analyzed its activity upon IFN-beta and dsRNA treatment. Under basal condition, RIG-I mRNA level and promoter activity were significantly higher in normal cells versus their tumor counterparts. In both normal and cancer cells, RIG-I expression was induced by IFN-beta and dsRNA. A single IRF-1 binding site in the proximal promoter functioned as a crucial regulator of basal, IFN-beta- and dsRNA-mediated induction of the RIG-I promoter. IFN-beta and dsRNA treatment increased IRF-1 binding to the RIG-I promoter. IRF-1 expression was also higher in normal cells than in cancer cells and it was induced by IFN-beta with similar kinetics as RIG-I. These results confirm that by controlling RIG-I expression, IRF-1 plays an essential role in anti-viral immunity. IRF-1 is a tumor suppressor and the expression profile of RIG-I together with its regulation by IRF-1 and the presence of a caspase-recruitment domain in RIG-I suggest that RIG-I might also possess tumor suppressor properties.
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Affiliation(s)
- Zao-Zhong Su
- Department of Urology, Herbert Irving Comprehensive Cancer Center, Columbia University Medical Center, College of Physicians and Surgeons, New York, New York 10032, USA
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31
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Altucci L, Leibowitz MD, Ogilvie KM, de Lera AR, Gronemeyer H. RAR and RXR modulation in cancer and metabolic disease. Nat Rev Drug Discov 2007; 6:793-810. [PMID: 17906642 DOI: 10.1038/nrd2397] [Citation(s) in RCA: 397] [Impact Index Per Article: 23.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Retinoic acid receptors (RARs) are ligand-controlled transcription factors that function as heterodimers with retinoid X receptors (RXRs) to regulate cell growth and survival. The success of RAR modulation in the treatment of acute promyelocytic leukaemia (APL) has stimulated considerable interest in the development of RAR and RXR modulators. This has been aided by recent advances in the understanding of the biological role of RARs and RXRs and in the design of selective receptor modulators that might overcome the limitations of current drugs. Here, we discuss the challenges and opportunities for therapeutic strategies based on RXR and RAR modulators, with a focus on cancer and metabolic diseases such as diabetes and obesity.
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Affiliation(s)
- Lucia Altucci
- Dipartimento di Patologia Generale, Seconda Università degli Studi di Napoli, Vico Luigi de Crecchio 7, 80138 Napoli, Italy
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32
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Andersen P, Pedersen MW, Woetmann A, Villingshøj M, Stockhausen MT, Ødum N, Poulsen HS. EGFR induces expression of IRF-1viaSTAT1 and STAT3 activation leading to growth arrest of human cancer cells. Int J Cancer 2007; 122:342-9. [DOI: 10.1002/ijc.23109] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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33
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Kröger A, Stirnweiss A, Pulverer JE, Klages K, Grashoff M, Reimann J, Hauser H. Tumor suppression by IFN regulatory factor-1 is mediated by transcriptional down-regulation of cyclin D1. Cancer Res 2007; 67:2972-81. [PMID: 17409403 DOI: 10.1158/0008-5472.can-06-3564] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
IFNs have been ascribed to mediate antitumor effects. IFN regulatory factor-1 (IRF-1) is a major target gene of IFNs. It inhibits cell proliferation and oncogenic transformation. Here, we show that 60% of all mRNAs deregulated by oncogenic transformation mediated by c-myc and H-ras are reverted to the expression levels of nontransformed cells by IRF-1. These include cell cycle-regulating genes. An indirect target is cyclin D1. Activation of IRF-1 decreased cyclin D1 expression and cyclin-dependent kinase 4 kinase activity concomitant with change in the levels of hyperphosphorylated retinoblastoma protein. These effects are mediated by inhibition of the mitogen-activated protein kinase kinase/extracellular signal-regulated kinase pathway and a transcriptional repression of cyclin D1. As shown by in vitro assays and tumor growth in nude mice, IRF-1-mediated effects on cell cycle progression were found to be overridden by ectopic expression of cyclin D1. Conversely, decrease of cyclin D1 by RNA interference experiments prevents transformation and tumor growth. The data show that cyclin D1 is a key target for IRF-1-mediated tumor-suppressive effects.
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MESH Headings
- Animals
- Cell Cycle/genetics
- Cell Transformation, Neoplastic/genetics
- Cyclin D1/antagonists & inhibitors
- Cyclin D1/biosynthesis
- Cyclin D1/genetics
- Cyclin-Dependent Kinase 4/antagonists & inhibitors
- Cyclin-Dependent Kinase 4/metabolism
- Down-Regulation
- Gene Expression Regulation, Neoplastic
- Genes, myc
- Genes, ras
- Interferon Regulatory Factor-1/genetics
- Male
- Mice
- Mice, Nude
- NIH 3T3 Cells
- Neoplasms, Experimental/genetics
- Neoplasms, Experimental/metabolism
- Oligonucleotide Array Sequence Analysis
- RNA, Messenger/biosynthesis
- RNA, Messenger/genetics
- Signal Transduction
- Transcription, Genetic
- Transfection
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Affiliation(s)
- Andrea Kröger
- Department of Gene Regulation and Differentiation, Helmholtz Center for Infection Research, Braunschweig, Germany.
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34
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Schlee M, Hölzel M, Bernard S, Mailhammer R, Schuhmacher M, Reschke J, Eick D, Marinkovic D, Wirth T, Rosenwald A, Staudt LM, Eilers M, Baran-Marszak F, Fagard R, Feuillard J, Laux G, Bornkamm GW. C-myc activation impairs the NF-kappaB and the interferon response: implications for the pathogenesis of Burkitt's lymphoma. Int J Cancer 2007; 120:1387-95. [PMID: 17211884 DOI: 10.1002/ijc.22372] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Deregulation of the proto-oncogene c-myc is a key event in the pathogenesis of many tumors. A paradigm is the activation of the c-myc gene by chromosomal translocations in Burkitt lymphoma (BL). Despite expression of a restricted set of Epstein-Barr viral (EBV) antigens, BL cells are not recognized by antigen-specific cytotoxic T cells (CTLs) because of their inability to process and present HLA class I-restricted antigens. In contrast, cells of EBV-driven posttransplant lymphoproliferative disease (PTLD) are recognized and rejected by EBV-specific CTLs. It is not known whether the poor immunogenicity of BL cells is due to nonexpression of viral antigens, overexpression of c-myc, or both. To understand the basis for immune recognition and escape, we have compared the mRNA expression profiles of BL and EBV-immortalized cells (as PTLD model). Among the genes expressed at low level in BL cells, we have identified many genes involved in the NF-kappaB and interferon response that play a pivotal role in antigen presentation and immune recognition. Using a cell line in which EBNA2 and c-myc can be regulated at will, we show that c-MYC negatively regulates STAT1, the central player linking the Type-I and Type-II interferon response. Switching off c-myc expression leads to STAT1 induction through a direct and indirect mechanism involving induction of Type-I interferons. c-MYC thus masks an interferon-inducing activity in these cells. Our findings imply that immune escape of tumor cells is not only a matter of in vivo selection but may be additionally promoted by activation of a cellular oncogene.
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Affiliation(s)
- Martin Schlee
- Institute of Clinical Molecular Biology and Tumor Genetics, GSF-National Research Center for Environment and Health, München, Germany
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35
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Ramsauer K, Farlik M, Zupkovitz G, Seiser C, Kröger A, Hauser H, Decker T. Distinct modes of action applied by transcription factors STAT1 and IRF1 to initiate transcription of the IFN-gamma-inducible gbp2 gene. Proc Natl Acad Sci U S A 2007; 104:2849-54. [PMID: 17293456 PMCID: PMC1815270 DOI: 10.1073/pnas.0610944104] [Citation(s) in RCA: 90] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
A subgroup of genes induced by IFN-gamma requires both STAT1 and IRF1 for transcriptional activation. Using WT, stat1(-/-), or irf1(-/-) cells, we analyzed the changes induced by IFN-gamma in gbp2 promoter chromatin. STAT1 associated with the promoter independently of IRF1 and played an essential role in the ordered recruitment of the coactivator/histone acetyl transferase CREB-binding protein (CBP) and the histone deacetylase HDAC1. Hyperacetylation of histone 4 also required STAT1. Phosphorylation at S727 in the transactivating domain increased transcriptional activity of STAT1. In cells expressing a STAT1S727A-mutant CBP recruitment, histone 4 hyperacetylation and RNA polymerase II association with the gbp2 promoter were strongly reduced. IRF1 association with the gbp2 promoter followed that of STAT1, but STAT1 association with DNA or histone hyperacetylation were not necessary for IRF1 binding. RNA polymerase II association with the gbp2 promoter required both STAT1 and IRF1, suggesting that both proteins mediate essential steps in transcriptional activation. IRF1, but not STAT1, was found to coimmunoprecipitate with RNA polymerase II. Together, the data support the assumption that the main role of STAT1 in activating gbp2 transcription is to provide transcriptionally competent chromatin, whereas the function of IRF1 may lie in directly contacting RNA polymerase II-containing transcriptional complexes.
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Affiliation(s)
- Katrin Ramsauer
- *Max F. Perutz Laboratories, Department of Microbiology and Immunobiology, University of Vienna, A1030 Vienna, Austria
| | - Matthias Farlik
- *Max F. Perutz Laboratories, Department of Microbiology and Immunobiology, University of Vienna, A1030 Vienna, Austria
| | - Gordin Zupkovitz
- Max F. Perutz Laboratories, Department of Medical Biochemistry, Medical University of Vienna, Dr. Bohr-Gasse 9, A1030 Vienna, Austria; and
| | - Christian Seiser
- Max F. Perutz Laboratories, Department of Medical Biochemistry, Medical University of Vienna, Dr. Bohr-Gasse 9, A1030 Vienna, Austria; and
| | - Andrea Kröger
- Gesellschaft für Biotechnologische Forschung, Mascheroder Weg 1, D-38124 Braunschweig, Germany
| | - Hansjörg Hauser
- Gesellschaft für Biotechnologische Forschung, Mascheroder Weg 1, D-38124 Braunschweig, Germany
| | - Thomas Decker
- *Max F. Perutz Laboratories, Department of Microbiology and Immunobiology, University of Vienna, A1030 Vienna, Austria
- To whom correspondence should be addressed. E-mail:
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36
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Contente S, Attard FA, Friedman RM. Identification of proteins immunologically related to interferon regulatory factor-1 that bind with interferon regulatory factor element. J Infect Dis 2006; 194 Suppl 1:S27-32. [PMID: 16921468 DOI: 10.1086/505358] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
Interferon regulatory factor (IRF)-1 expression was surveyed in nontransformed and oncogene-transformed mouse fibroblasts, using Western immunoblot with an IRF-1-specific antiserum, to examine possible differences resulting from cellular transformation. Ten additional proteins that reacted with the IRF-1 antibody and that underwent specific competition by peptide antigen were observed in extracts of both nontransformed and oncogene-transformed cell lines. Cross-reacting proteins were also observed in mouse macrophage extracts. Protein was captured from fibroblast nuclear extracts, using oligonucleotides representing IRF-binding sequences linked to magnetic beads. Captured proteins were eluted and analyzed by immunoblot with anti-IRF-1. Along with 43-kDa IRF-1, 4 of the 7 nuclearly located cross-reacting proteins (97, 90, 66, and 33 kDa) were found to complex with the IRF binding element. These proteins, with an epitope in common with the IRF-1 C-terminal region and IRF element DNA sequence-binding capability, may represent new members of the IRF family.
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Affiliation(s)
- Sara Contente
- Department of Pathology and United States Military Cancer Institute, Uniformed Services University of the Health Sciences, Bethesda, MD, 20814, USA.
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37
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Lee EJ, Jo M, Park J, Zhang W, Lee JH. Alternative splicing variants of IRF-1 lacking exons 7, 8, and 9 in cervical cancer. Biochem Biophys Res Commun 2006; 347:882-8. [PMID: 16857162 DOI: 10.1016/j.bbrc.2006.06.145] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2006] [Accepted: 06/26/2006] [Indexed: 11/20/2022]
Abstract
The two previously identified major splice variants of interferon regulatory factor 1 (IRF-1) do not appear to affect IRF-1-mediated gene activation. We searched for additional splice variants and examined their effect on wild-type IRF-1. RT-PCR experiments using normal and malignant human cervical tissue samples revealed five variants lacking some combination of exons 7, 8, and 9; their expression levels were higher in the malignant samples. These variants had predicted deletions of the functional domain or truncated protein isoforms, had different transcriptional activities, and attenuated transcriptional activity of IRF-1. Unlike the cell cycle-dependent IRF-1 transcript, the splice variant mRNA levels remained consistent throughout the cell cycle. The variant proteins were more stable than the IRF-1 protein, which may explain the strong inhibition of IRF-1 transcription in the presence of relatively small quantities of the alternative transcripts. In conclusion, alternative splicing in exons 7, 8, and 9 is an important mechanism for negatively regulating IRF-1 in cervical cancer.
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Affiliation(s)
- Eun-Ju Lee
- Molecular Therapy Research Center, Sungkyunkwan University, Seoul 135-710, Republic of Korea
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38
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Watson GA, Queiroz de Oliveira PE, Stang MT, Armstrong MJ, Gooding WE, Kuan SF, Yim JH, Hughes SJ. Ad-IRF-1 induces apoptosis in esophageal adenocarcinoma. Neoplasia 2006; 8:31-7. [PMID: 16533423 PMCID: PMC1584287 DOI: 10.1593/neo.05559] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
The nuclear transcription factor interferon regulatory factor-1 (IRF-1) is a putative tumor suppressor, but the expression and function of IRF-1 in esophageal adenocarcinoma (EA) remain unknown. We hypothesized that IRF-1 expression was reduced or lost in EA and that restoration of IRF-1 would result in the apoptosis of EA cells in vitro and the inhibition of tumor growth in vivo. Three EA cell lines were used to examine IRF-1 expression, IFN-gamma responsiveness, and the effects of IRF-1 overexpression using a recombinant adenoviral vector (Ad-IRF-1). All three EA cell lines produced IRF-1 protein following IFN-gamma stimulation, although IFN-gamma did not induce cell death. In contrast, Ad-IRF-1 infection resulted in high levels of IRF-1 protein and triggered apoptosis in all three EA cell lines. Potential mechanisms for the differential response to IFN-gamma versus Ad-IRF-1--such as modulation of c-Met or extracellular regulated kinase signaling, or altered expression of IRF-2, Fas, or survivin--were investigated, but none of these mechanisms can account for this observation. In vivo administration of IRF-1 in a murine model of EA modestly inhibited tumor growth, but did not lead to tumor regression. Strategies aimed at increasing or restoring IRF-1 expression may have therapeutic benefits in EA.
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Affiliation(s)
- Gregory A Watson
- Department of Surgery, University of Pittsburgh, Pittsburgh, PA, USA
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39
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May T, Hauser H, Wirth D. Current status of transcriptional regulation systems. Cytotechnology 2006; 50:109-19. [PMID: 19003074 DOI: 10.1007/s10616-006-9007-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/31/2006] [Indexed: 10/24/2022] Open
Abstract
Many attempts have been undertaken to control transgene activity in mammalian cells. This is of importance for both applied biotechnology and basic research activities. State of the art regulatory systems use elements for transgene regulation which are unrelated to host regulatory networks and thus do not interfere with endogenous activities. Most of these regulation systems consist of transregulators and transregulator responding promoter elements that are derived from non mammalian origin. Apart from the tetracycline (Tet) regulated system which is most widely used for conditional gene expression at the moment, a number of new systems were created. These systems have been significantly refined and their performance makes them suitable for regulating transgenes not only in cellular systems but also in transgenic animals and for human therapeutic use.
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Affiliation(s)
- Tobias May
- Department of Gene Regulation and Differentiation, GBF-German Research Center for Biotechnology, Mascheroder Weg 1, Braunschweig, D-38124, Germany
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40
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Eckert M, Meek SEM, Ball KL. A novel repressor domain is required for maximal growth inhibition by the IRF-1 tumor suppressor. J Biol Chem 2006; 281:23092-102. [PMID: 16679314 DOI: 10.1074/jbc.m512589200] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Interferon regulatory factor-1 (IRF-1) is a transcription factor and tumor suppressor that can regulate gene expression in a manner requiring either its sequence specific DNA binding activity or its ability to bind the p300 coactivator. We show that IRF-1-mediated growth inhibition is dependent on the integrity of a C-terminal transcriptional enhancer domain. An enhancer subdomain (amino acids 301-325) that differentially regulates IRF-1 activity has been identified and this region mediates the repression of Cdk2. The repressor domain encompasses an LXXLL coregulator signature motif and mutations or deletions within this region completely uncouple transcriptional activation from repression. The loss of growth suppressor activity when the Cdk2-repressor domain of IRF-1 is mutated implicates repression as a determinant of its maximal growth inhibitory potential. The data link IRF-1 regulatory domains to its growth inhibitory activity and provide information about how differential gene regulation may contribute to IRF-1 tumor suppressor activity.
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Affiliation(s)
- Mirjam Eckert
- Cancer Research UK (CRUK) Interferon and Cell Signalling Group, Cell Signalling Unit, The University of Edinburgh Cancer Research Centre, Edinburgh EH4 2XR, United Kingdom
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41
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Luo XM, Ross AC. Physiological and receptor-selective retinoids modulate interferon gamma signaling by increasing the expression, nuclear localization, and functional activity of interferon regulatory factor-1. J Biol Chem 2005; 280:36228-36. [PMID: 16085646 PMCID: PMC3846428 DOI: 10.1074/jbc.m505749200] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Synergistic actions between all-trans-retinoic acid (atRA) and interferon gamma (IFNgamma) on modulation of cellular functions have been reported both in vitro and in vivo. However, the mechanism of atRA-mediated regulation of IFNgamma signaling is poorly understood. In this study, we have used the human lung epithelial cell line A549 to examine the effect of atRA on IFNgamma-induced expression of IFN regulatory factor-1 (IRF-1), an important transcription factor involved in cell growth and apoptosis, differentiation, and antiviral and antibacterial immune responses. At least 4 h of pretreatment with atRA followed by suboptimal concentrations of IFNgamma induced a faster, higher, and more stable expression of IRF-1 than IFNgamma alone. Actinomycin D completely blocked the induction of IRF-1 by the combination, suggesting regulation at the transcriptional level. Further, we found that activation of signal transducer and activator of transcription-1 was induced more dramatically by atRA and IFNgamma than by IFNgamma alone. Expression of IFNgamma receptor-1 on the cell surface was also increased upon atRA pretreatment. Experiments using receptor-selective retinoids revealed that ligands for retinoic acid receptor-alpha (RARalpha), including atRA, 9-cis-retinoic acid, and Am580, sequentially increased the levels of IFNgamma receptor-1, activated signal transducer and activator of transcription-1, and IRF-1 and that an RARalpha antagonist was able to inhibit the effects of atRA and Am580. In addition, atRA pretreatment affected the transcriptional functions of IFNgamma-induced IRF-1, increasing its nuclear localization and DNA binding activity as well as the transcript levels of IRF-1 target genes. These results suggest that atRA, an RARalpha ligand, regulates IFNgamma-induced IRF-1 by affecting multiple components of the IFNgamma signaling pathway, from the plasma membrane to the nuclear transcription factors.
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Affiliation(s)
- Xin M. Luo
- Department of Nutritional Sciences, The Pennsylvania State University, University Park, Pennsylvania 16802
- Graduate Program in Integrative Biosciences, The Pennsylvania State University, University Park, Pennsylvania 16802
| | - A. Catharine Ross
- Department of Nutritional Sciences, The Pennsylvania State University, University Park, Pennsylvania 16802
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42
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May T, Mueller PP, Weich H, Froese N, Deutsch U, Wirth D, Kröger A, Hauser H. Establishment of murine cell lines by constitutive and conditional immortalization. J Biotechnol 2005; 120:99-110. [PMID: 16026879 DOI: 10.1016/j.jbiotec.2005.03.027] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2004] [Revised: 03/01/2005] [Accepted: 03/16/2005] [Indexed: 10/25/2022]
Abstract
Mouse cell lines were immortalized by introduction of specific immortalizing genes. Embryonic and adult animals and an embryonal stem cell line were used as a source of primary cells. The immortalizing genes were either introduced by DNA transfection or by ecotropic retrovirus transduction. Fibroblasts were obtained by expression of SV40 virus large T antigen (TAg). The properties of the resulting fibroblast cell lines were reproducible, independent of the donor mouse strains employed and the cells showed no transformed properties in vitro and did not form tumors in vivo. Endothelial cell lines were generated by Polyoma virus middle T antigen expression in primary embryonal cells. These cell lines consistently expressed relevant endothelial cell surface markers. Since the expression of the immortalizing genes was expected to strongly influence the cellular characteristics fibroblastoid cells were reversibly immortalized by using a vector that allows conditional expression of the TAg. Under inducing conditions, these cells exhibited properties that were highly similar to the properties of constitutively immortalized cells. In the absence of TAg expression, cell proliferation stops. Cell growth is resumed when TAg expression is restored. Gene expression profiling indicates that TAg influences the expression levels of more than 1000 genes that are involved in diverse cellular processes. The data show that conditionally immortalized cell lines have several advantageous properties over constitutively immortalized cells.
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Affiliation(s)
- Tobias May
- Department of Gene Regulation and Differentiation, German Research Center for Biotechnology, GBF, Mascheroder Weg 1, D-38124 Braunschweig, Germany
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Marth C, Fiegl H, Zeimet AG, Müller-Holzner E, Deibl M, Doppler W, Daxenbichler G. Interferon-gamma expression is an independent prognostic factor in ovarian cancer. Am J Obstet Gynecol 2004; 191:1598-605. [PMID: 15547530 DOI: 10.1016/j.ajog.2004.05.007] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND Epithelial ovarian cancer prognosis is improved by the presence of intratumoral CD3 + T cells, which are known to produce interferon-gamma. We therefore speculated that interferon-gamma expression in ovarian cancer-infiltrating T-lymphocytes might cause better prognosis. PATIENTS AND METHODS Reverse transcriptase polymerase chain reaction was performed to measure the expression of interferon-gamma and other related genes in normal ovaries (n = 19) and in ovarian cancer specimens (n = 99). Median follow-up of patients was 5.8 years. RESULTS Interferon-gamma and CD-3 expression did not significantly differ in normal and malignant tissue. Patients with high levels of interferon-gamma expression had significantly longer progression-free and overall survival. Median time to progression was 10 and 29 months for patients with low and high interferon-gamma expression, respectively ( P = .039). Corresponding survival times were 29 and 44 months ( P < .032). Application of multivariate Cox regression analysis showed interferon-gamma expression to be an independent prognostic factor for progression-free and overall survival. CONCLUSION Elevated interferon-gamma expression correlates with improved clinical outcome in patients with ovarian cancer.
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Affiliation(s)
- Christian Marth
- Department of Obstetrics and Gynecology, Innsbruck Medical University, Innsbruck, Austria.
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Contente S, Attard FA, Yeh TJA, Buchhagen DL, Friedman RM. Deregulated expression of interferon regulatory factor-1 in oncogene-transformed mouse fibroblasts. J Interferon Cytokine Res 2004; 23:639-47. [PMID: 14651778 DOI: 10.1089/107999003322558773] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Interferon (IFN) regulatory factor-1 (IRF-1) is a transcription factor that has been historically associated with type I IFN activation and antioncogenic properties. We studied IRF-1 expression and DNA-binding capacity in nontransformed and transformed mouse fibroblasts. A 43-kDa nuclear IRF-1 protein was expressed biphasically during the cell cycle in primary mouse embryo fibroblasts, nontransformed NIH 3T3 cells, and ras revertants. IRF-1 expression became constitutive in ras-transformed NIH 3T3 cells and in cells transformed by oncogenes ets, fes, fos, her-2/neu, met, mos, raf, or trk, suggesting that deregulated IRF-1 expression may be associated with loss of growth control. Lysyl oxidase (LO), a ras suppressor that is downregulated in ras transformants, is an IRF-1 target gene, but it is not stimulated by abundant IRF-1 present in transformants, while another IRF-1 target gene (iNOS) is transcribed. IRF-1 from either normal or ras-transformed cells bound to IRF elements in the IFN-beta and LO promoters. IRF-1 in transformants can, therefore, bind to but not transactivate the LO promoter, and the presence of IRF-1 is not sufficient to suppress ras transformation. LO expression may effect the regulated expression of IRF-1: a ras revertant, which was generated by stable transfection of LO cDNA, regained the normal biphasic IRF-1 pattern. A mainly cytoplasmic, constitutively expressed 46-kDa protein with immunologic identity to the 43-kDa nuclear IRF-1 was also present in normal and transformed cells, but as it did not bind to the IRF elements, its function is unclear.
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Affiliation(s)
- Sara Contente
- United States Military Cancer Institute, Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA.
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Kim PKM, Armstrong M, Liu Y, Yan P, Bucher B, Zuckerbraun BS, Gambotto A, Billiar TR, Yim JH. IRF-1 expression induces apoptosis and inhibits tumor growth in mouse mammary cancer cells in vitro and in vivo. Oncogene 2004; 23:1125-35. [PMID: 14762441 DOI: 10.1038/sj.onc.1207023] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Interferon regulatory factor-1 (IRF-1) is a nuclear transcription factor that mediates interferon and other cytokine effects and appears to have antitumor activity in vitro and in vivo in cancer cells. We have constructed a recombinant adenoviral vector (Ad-IRF-1) that infects mammary cells with high efficiency and results in high levels of functional IRF-1 protein in transfected cells. Overexpression of IRF-1 in two mouse breast cancer cell lines, C3-L5 and TS/A, resulted in apoptosis in these cell lines as assessed by Annexin V staining. The involvement of caspases was confirmed by significant inhibition of apoptosis by a caspase inhibitor, and by demonstration of caspase-3 activity, cleavage of caspase-3, and PARP cleavage. Interestingly, the growth of nonmalignant breast cell lines C127I and NMuMG did not appear to be inhibited by IRF-1 overexpression. Suppression of growth for breast cancer cell lines in vivo was demonstrated by both preinfection of breast cancer cells ex vivo and by intratumoral injection of Ad-IRF-1 into established tumors in their natural hosts. The mechanism of apoptosis may involve the transcriptional upregulation of bak, caspase-8, and caspase-7 expression. These data support the antitumor potential of IRF-1 and the use of agents that increase IRF-1 in breast cancer.
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Affiliation(s)
- Peter K M Kim
- Department of Surgery, University of Pittsburgh Medical Center, 497 Scaife Hall, 3550 Terrace Street, Pittsburgh, PA 15261, USA
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Klampfer L, Huang J, Corner G, Mariadason J, Arango D, Sasazuki T, Shirasawa S, Augenlicht L. Oncogenic Ki-ras inhibits the expression of interferon-responsive genes through inhibition of STAT1 and STAT2 expression. J Biol Chem 2003; 278:46278-87. [PMID: 12972432 DOI: 10.1074/jbc.m304721200] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Endogenous interferon gamma (IFNgamma) promotes the host response to primary tumors, and IFNgamma-insensitive tumors display increased tumorigenicity and can evade tumor surveillance mechanisms. Here we demonstrate that activating mutations of Ki-ras are sufficient to inhibit the expression of STAT1 and STAT2, transcription factors required for signaling by IFNs, providing a potential mechanism for the insensitivity of tumors to IFNs. We demonstrated that colon cancer cell lines with Ki-ras mutations display reduced expression of IFN-responsive genes compared with the cell lines that have retained wild type Ras and that inactivation of the mutant Ki-ras allele in the HCT116 colon cancer cell line is sufficient to restore the expression of STAT1, STAT2, and IRF-9. Accordingly, the expression of 27 interferon-inducible genes was reduced in HCT116 cells compared with the isogenic clones with targeted deletion of the mutant Ki-ras allele, Hkh2 and Hke-3. The expression of IFNgamma receptors did not differ among the isogenic cell lines. IFNgamma stimulated transcription of a STAT1-dependent reporter gene was impaired by RasV12, demonstrating a transmodulation of IFN/STAT signaling by activated Ras. Finally, we demonstrated that the expression of RasV12 in 293T cells is sufficient to inhibit the endogenous expression of STAT1 and STAT2, confirming the negative regulation of IFN signaling by oncogenic Ras. Our data demonstrate that the signaling initiated by activated Ki-ras interferes with the IFN/STAT signaling pathway and modulates the responsiveness of cancer cells to interferons. Furthermore, the data suggest that tumors harboring activating Ki-ras mutations may escape tumor surveillance mechanisms due to reduced responsiveness to IFNgamma.
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Affiliation(s)
- Lidija Klampfer
- Department of Oncology, Albert Einstein Cancer Center, Montefiore Medical Center, 111 E. 210th Street, Bronx, NY 10467, USA.
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