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Cancer Treatment Goes Viral: Using Viral Proteins to Induce Tumour-Specific Cell Death. Cancers (Basel) 2019; 11:cancers11121975. [PMID: 31817939 PMCID: PMC6966515 DOI: 10.3390/cancers11121975] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Revised: 12/04/2019] [Accepted: 12/05/2019] [Indexed: 12/24/2022] Open
Abstract
Cell death is a tightly regulated process which can be exploited in cancer treatment to drive the killing of the tumour. Several conventional cancer therapies including chemotherapeutic agents target pathways involved in cell death, yet they often fail due to the lack of selectivity they have for tumour cells over healthy cells. Over the past decade, research has demonstrated the existence of numerous proteins which have an intrinsic tumour-specific toxicity, several of which originate from viruses. These tumour-selective viral proteins, although from distinct backgrounds, have several similar and interesting properties. Though the mechanism(s) of action of these proteins are not fully understood, it is possible that they can manipulate several cell death modes in cancer exemplifying the intricate interplay between these pathways. This review will discuss our current knowledge on the topic and outstanding questions, as well as deliberate the potential for viral proteins to progress into the clinic as successful cancer therapeutics.
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Insulin receptor substrate-4 is overexpressed in colorectal cancer and promotes retinoblastoma-cyclin-dependent kinase activation. J Gastroenterol 2018; 53:932-944. [PMID: 29353348 DOI: 10.1007/s00535-018-1432-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/14/2017] [Accepted: 01/12/2018] [Indexed: 02/04/2023]
Abstract
BACKGROUND Insulin receptor substrate 4 (IRS-4) is an adaptor protein for which new evidence suggests plays a role in tumour promotion. METHODS We described nuclear IRS-4 in RKO colon cancer cell lines in biopsies of patients with colorectal cancer (CRC) (n = 20) and in matched adjacent normal colorectal (MANC) tissue (n = 20). RESULTS Treatment with physiological doses of IGF-1 promoted nuclear influx of IRS-4 from cellular cytosol in RKO cells. When exogenous IRS-4 was overexpressed in RKO cells, there was an increase in cyclin D1, cyclin E, E2F1, pRB Ser 809/811 and pRB Ser 705 levels compared with the empty vector-transfected cells. Some of these changes returned to control values after wortmannin treatment. Subcellular fractionation showed an overexpression of IRS-4 in the cytoplasm, membrane, and nuclei of tumour samples, whereas the levels of the protein were barely detectable in the three compartments of normal samples. Immunohistochemical studies showed positive nuclear IRS-4 staining in over 74% of the tumour cells. IRS-4 was strongly overexpressed in tumoural tissues from CRC patients compared to MANC tissues. The up-regulation of IRS-4 in CRC samples correlated significantly with the increase of several G1 checkpoint proteins including cyclin D1 (r = 0.6662), Rb (r = 0.7779), pRb Serine 809/811 (r = 0.6864), pRb serine 705 (r = 0.6261) and E2F1 (r = 0.8702). CONCLUSIONS Taken together, our findings suggest that IRS-4 promotes retinoblastoma-cyclin-dependent kinase activation and it may serve as a pharmacological target since its expression is very low in normal tissue, including colonic epithelium.
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Li X, Zhong L, Wang Z, Chen H, Liao D, Zhang R, Zhang H, Kang T. Phosphorylation of IRS4 by CK1γ2 promotes its degradation by CHIP through the ubiquitin/lysosome pathway. Am J Cancer Res 2018; 8:3643-3653. [PMID: 30026872 PMCID: PMC6037025 DOI: 10.7150/thno.26021] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2018] [Accepted: 05/04/2018] [Indexed: 01/08/2023] Open
Abstract
IRS4, a member of the insulin receptor substrate protein family, can induce constitutive PI3K/AKT hyperactivation and cell proliferation even in the absence of insulin or growth factors and promote tumorigenesis, but its regulation has only been explored at the transcriptional level. Methods: Scansite was used to predict the potential protein kinases that may regulate the functions of IRS4, and mass spectrometry was used to identify the E3 ligase for IRS4. The protein interaction was carried out by immunoprecipitation, and protein stability was measured by cycloheximide treatment. In vitro kinase assay was used to determine the phosphorylation of IRS4 by casein kinase 1γ2 (CK1γ2). Colony formation assay and xenograft-bearing mice were employed to assess the cancer cell growth in vitro and in vivo, respectively. Immunohistochemistry was performed to examine protein levels of both IRS4 and CK1γ2 in osteosarcoma specimens and their relationship was evaluated by χ2 test. Two-tailed Student's t-test or the Mann-Whitney U test were used to compare the differences between subgroups. Results: IRS4 was phosphorylated at Ser859 by CK1γ2 in vitro and in vivo, which promoted the polyubiquitination and degradation of IRS4 through the ubiquitin/lysosome pathway by the carboxyl terminus of Hsc70-interacting protein(CHIP). Using osteosarcoma cell lines, the ectopic nonphosphorylated mutant of IRS4 by CK1γ2 triggered higher level of p-Akt and displayed faster cell proliferation and cancer growth in vitro and in nude mice. In addition, a negative correlation in protein levels between CK1γ2 and IRS4 was observed in osteosarcoma cell lines and tissue samples. Conclusions: IRS4, as a new substrate of CHIP, is negatively regulated by CK1γ2 at the posttranslational level, and specific CK1γ2 agonists may be a potentially effective strategy for treating patients with osteosarcoma.
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Jiao B, Shi X, Chen Y, Ye H, Yao M, Hong W, Li S, Duan X, Li Y, Wang Y, Chen L. Insulin receptor substrate-4 interacts with ubiquitin-specific protease 18 to activate the Jak/STAT signaling pathway. Oncotarget 2017; 8:105923-105935. [PMID: 29285303 PMCID: PMC5739690 DOI: 10.18632/oncotarget.22510] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2017] [Accepted: 11/03/2017] [Indexed: 12/23/2022] Open
Abstract
Ubiquitin-specific protease 18 (USP18) as a negative regulator of the Jak/STAT signaling pathway plays an important role in the host innate immune response. USP18 has been shown to bind to the type I interferon receptor subunit 2 (IFNAR2) to down-regulate the Jak/STAT signaling. In this study, we showed that insulin receptor substrate (IRS)-4 functioned as a novel USP18-binding protein. Co-precipitation assays revealed that two regions (amino acids 335–400 and 1094-1257) of IRS4 were related to bind to the C- terminal region of USP18. IRS4 binding to USP18 diminished the inhibitory effect of USP18 on Jak/STAT signaling. IRS4 over-expression enhanced while IRS4 knock-down suppressed the Jak/STAT signaling in the presence of IFN-a stimulation. As such, IRS4 increased IFN-a-mediated anti-HCV activity. Mechanistically, IRS4 promoted the IFN-a-induced Jak/STAT signaling by interact with USP18. These results suggested that IRS4 binds to USP18 to diminish the blunting effect of USP18 on IFN-a-induced Jak/STAT signaling. Our findings indicated that IRS4 is a novel USP18-binding protein that can be used to boost the host innate immunity to control HCV, and potentially other viruses that are sensitive to IFN-a.
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Affiliation(s)
- Baihai Jiao
- Institute of Blood Transfusion, Chinese Academy of Medical Sciences and Peking Union Medical College, Provincial Key Laboratory for Transfusion-Transmitted Infectious Diseases of Sichuan Province, Chengdu 610052, China
| | - Xuezhen Shi
- Institute of Blood Transfusion, Chinese Academy of Medical Sciences and Peking Union Medical College, Provincial Key Laboratory for Transfusion-Transmitted Infectious Diseases of Sichuan Province, Chengdu 610052, China
| | - Yanzhao Chen
- Institute of Blood Transfusion, Chinese Academy of Medical Sciences and Peking Union Medical College, Provincial Key Laboratory for Transfusion-Transmitted Infectious Diseases of Sichuan Province, Chengdu 610052, China
| | - Haiyan Ye
- Institute of Blood Transfusion, Chinese Academy of Medical Sciences and Peking Union Medical College, Provincial Key Laboratory for Transfusion-Transmitted Infectious Diseases of Sichuan Province, Chengdu 610052, China
| | - Min Yao
- Institute of Blood Transfusion, Chinese Academy of Medical Sciences and Peking Union Medical College, Provincial Key Laboratory for Transfusion-Transmitted Infectious Diseases of Sichuan Province, Chengdu 610052, China
| | - Wenxu Hong
- Key Laboratory of Shenzhen for Histocompatibility and Immunogenetics, Shenzhen Blood Center, Shenzhen 518000, China
| | - Shilin Li
- Institute of Blood Transfusion, Chinese Academy of Medical Sciences and Peking Union Medical College, Provincial Key Laboratory for Transfusion-Transmitted Infectious Diseases of Sichuan Province, Chengdu 610052, China
| | - Xiaoqiong Duan
- Institute of Blood Transfusion, Chinese Academy of Medical Sciences and Peking Union Medical College, Provincial Key Laboratory for Transfusion-Transmitted Infectious Diseases of Sichuan Province, Chengdu 610052, China
| | - Yujia Li
- Institute of Blood Transfusion, Chinese Academy of Medical Sciences and Peking Union Medical College, Provincial Key Laboratory for Transfusion-Transmitted Infectious Diseases of Sichuan Province, Chengdu 610052, China
| | - Yancui Wang
- Institute of Blood Transfusion, Chinese Academy of Medical Sciences and Peking Union Medical College, Provincial Key Laboratory for Transfusion-Transmitted Infectious Diseases of Sichuan Province, Chengdu 610052, China
| | - Limin Chen
- Institute of Blood Transfusion, Chinese Academy of Medical Sciences and Peking Union Medical College, Provincial Key Laboratory for Transfusion-Transmitted Infectious Diseases of Sichuan Province, Chengdu 610052, China.,Toronto General Research Institute, University Network and University of Toronto, Toronto M5G 1L6, Canada
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IRS4, a novel modulator of BMP/Smad and Akt signalling during early muscle differentiation. Sci Rep 2017; 7:8778. [PMID: 28821740 PMCID: PMC5562708 DOI: 10.1038/s41598-017-08676-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2017] [Accepted: 07/12/2017] [Indexed: 12/27/2022] Open
Abstract
Elaborate regulatory networks of the Bone Morphogenetic Protein (BMP) pathways ensure precise signalling outcome during cell differentiation and tissue homeostasis. Here, we identified IRS4 as a novel regulator of BMP signal transduction and provide molecular insights how it integrates into the signalling pathway. We found that IRS4 interacts with the BMP receptor BMPRII and specifically targets Smad1 for proteasomal degradation consequently leading to repressed BMP/Smad signalling in C2C12 myoblasts while concomitantly activating the PI3K/Akt axis. IRS4 is present in human and primary mouse myoblasts, the expression increases during myogenic differentiation but is downregulated upon final commitment coinciding with Myogenin expression. Functionally, IRS4 promotes myogenesis in C2C12 cells, while IRS4 knockdown inhibits differentiation of myoblasts. We propose that IRS4 is particularly critical in the myoblast stage to serve as a molecular switch between BMP/Smad and Akt signalling and to thereby control cell commitment. These findings provide profound understanding of the role of BMP signalling in early myogenic differentiation and open new ways for targeting the BMP pathway in muscle regeneration.
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Differential control of ageing and lifespan by isoforms and splice variants across the mTOR network. Essays Biochem 2017; 61:349-368. [PMID: 28698309 DOI: 10.1042/ebc20160086] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2017] [Revised: 05/19/2017] [Accepted: 05/23/2017] [Indexed: 11/17/2022]
Abstract
Ageing can be defined as the gradual deterioration of physiological functions, increasing the incidence of age-related disorders and the probability of death. Therefore, the term ageing not only reflects the lifespan of an organism but also refers to progressive functional impairment and disease. The nutrient-sensing kinase mTOR (mammalian target of rapamycin) is a major determinant of ageing. mTOR promotes cell growth and controls central metabolic pathways including protein biosynthesis, autophagy and glucose and lipid homoeostasis. The concept that mTOR has a crucial role in ageing is supported by numerous reports on the lifespan-prolonging effects of the mTOR inhibitor rapamycin in invertebrate and vertebrate model organisms. Dietary restriction increases lifespan and delays ageing phenotypes as well and mTOR has been assigned a major role in this process. This may suggest a causal relationship between the lifespan of an organism and its metabolic phenotype. More than 25 years after mTOR's discovery, a wealth of metabolic and ageing-related effects have been reported. In this review, we cover the current view on the contribution of the different elements of the mTOR signalling network to lifespan and age-related metabolic impairment. We specifically focus on distinct roles of isoforms and splice variants across the mTOR network. The comprehensive analysis of mouse knockout studies targeting these variants does not support a tight correlation between lifespan prolongation and improved metabolic phenotypes and questions the strict causal relationship between them.
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Yuan S, Wu Y, Wang Y, Chen J, Chu L. An Oncolytic Adenovirus Expressing SNORD44 and GAS5 Exhibits Antitumor Effect in Colorectal Cancer Cells. Hum Gene Ther 2017; 28:690-700. [PMID: 28530127 DOI: 10.1089/hum.2017.041] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
SNORD44 is a C/D box small nucleolar RNA, and exhibits low expression in breast cancer and head and neck squamous cell carcinoma tissues. Its host gene is growth arrest specific transcript 5 (GAS5), which is a long noncoding RNA. GAS5 is downregulated in colorectal cancer (CRC), and overexpression of GAS5 suppresses cell proliferation. However, the function of SNORD44 in CRC remains largely unknown, and the application of SNORD44 combined with GAS5 in CRC treatment has not been reported. In this study, the expression levels of SNORD44 and GAS5 were measured in CRC tissues by quantitative RT-PCR. The correlation between SNORD44 and GAS5 was evaluated by Pearson correlation analysis. An oncolytic adenovirus expressing SNORD44 and GAS5 (SPDD-UG) was constructed. The biological effects of SPDD-UG were investigated in CRC cell line SW620 and LS174T in vitro and in xenografts. The synergistic effect of rapamycin and SPDD-UG was explored in SW620 and LS174T cells and tumors. We demonstrated that SNORD44 expression level was markedly decreased in CRC tissues and positively correlated with GAS5 expression. SPDD-UG significantly inhibited SW620 and LS174T cell growth and induced cell apoptosis. Intratumoral injection of SPDD-UG significantly suppressed xenografts growth in nude mice. Moreover, the mechanistic target of rapamycin (mTOR) inhibitor, rapamycin, enhanced the antitumor effect through antagonizing the PI3K/Akt pathway activated by SPDD-UG. These results suggest that overexpression of SNORD44 and GAS5 by oncolytic adenovirus provides a promising method for CRC therapy.
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Affiliation(s)
- Sujing Yuan
- 1 Hepatic Surgery Center, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology , Wuhan, China
| | - Yu Wu
- 1 Hepatic Surgery Center, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology , Wuhan, China
| | - Yigang Wang
- 2 Xinyuan Institute of Medicine and Biotechnology, School of Life Sciences, Zhejiang Sci-Tech University , Hangzhou, China
| | - Jianhua Chen
- 3 State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, School of Medicine, Shanghai Jiao Tong University , Shanghai, China
| | - Liang Chu
- 1 Hepatic Surgery Center, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology , Wuhan, China
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Pan-cancer analysis of somatic copy-number alterations implicates IRS4 and IGF2 in enhancer hijacking. Nat Genet 2016; 49:65-74. [PMID: 27869826 DOI: 10.1038/ng.3722] [Citation(s) in RCA: 272] [Impact Index Per Article: 34.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Accepted: 10/19/2016] [Indexed: 02/06/2023]
Abstract
Extensive prior research focused on somatic copy-number alterations (SCNAs) affecting cancer genes, yet the extent to which recurrent SCNAs exert their influence through rearrangement of cis-regulatory elements (CREs) remains unclear. Here we present a framework for inferring cancer-related gene overexpression resulting from CRE reorganization (e.g., enhancer hijacking) by integrating SCNAs, gene expression data and information on topologically associating domains (TADs). Analysis of 7,416 cancer genomes uncovered several pan-cancer candidate genes, including IRS4, SMARCA1 and TERT. We demonstrate that IRS4 overexpression in lung cancer is associated with recurrent deletions in cis, and we present evidence supporting a tumor-promoting role. We additionally pursued cancer-type-specific analyses and uncovered IGF2 as a target for enhancer hijacking in colorectal cancer. Recurrent tandem duplications intersecting with a TAD boundary mediate de novo formation of a 3D contact domain comprising IGF2 and a lineage-specific super-enhancer, resulting in high-level gene activation. Our framework enables systematic inference of CRE rearrangements mediating dysregulation in cancer.
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Su BH, Shieh GS, Tseng YL, Shiau AL, Wu CL. Etoposide enhances antitumor efficacy of MDR1-driven oncolytic adenovirus through autoupregulation of the MDR1 promoter activity. Oncotarget 2016; 6:38308-26. [PMID: 26515462 PMCID: PMC4742001 DOI: 10.18632/oncotarget.5702] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2015] [Accepted: 10/06/2015] [Indexed: 12/11/2022] Open
Abstract
Conditionally replicating adenoviruses (CRAds), or oncolytic adenoviruses, such as E1B55K-deleted adenovirus, are attractive anticancer agents. However, the therapeutic efficacy of E1B55K-deleted adenovirus for refractory solid tumors has been limited. Environmental stress conditions may induce nuclear accumulation of YB-1, which occurs in multidrug-resistant and adenovirus-infected cancer cells. Overexpression and nuclear localization of YB-1 are associated with poor prognosis and tumor recurrence in various cancers. Nuclear YB-1 transactivates the multidrug resistance 1 (MDR1) genes through the Y-box. Here, we developed a novel E1B55K-deleted adenovirus driven by the MDR1 promoter, designed Ad5GS3. We tested the feasibility of using YB-1 to transcriptionally regulate Ad5GS3 replication in cancer cells and thereby to enhance antitumor efficacy. We evaluated synergistic antitumor effects of oncolytic virotherapy in combination with chemotherapy. Our results show that adenovirus E1A induced E2F-1 activity to augment YB-1 expression, which shut down host protein synthesis in cancer cells during adenovirus replication. In cancer cells infected with Ad5WS1, an E1B55K-deleted adenovirus driven by the E1 promoter, E1A enhanced YB-1 expression, and then further phosphorylated Akt, which, in turn, triggered nuclear translocation of YB-1. Ad5GS3 in combination with chemotherapeutic agents facilitated nuclear localization of YB-1 and, in turn, upregulated the MDR1 promoter activity and enhanced Ad5GS3 replication in cancer cells. Thus, E1A, YB-1, and the MDR1 promoter form a positive feedback loop to promote Ad5GS3 replication in cancer cells, and this regulation can be further augmented when chemotherapeutic agents are added. In the in vivo study, Ad5GS3 in combination with etoposide synergistically suppressed tumor growth and prolonged survival in NOD/SCID mice bearing human lung tumor xenografts. More importantly, Ad5GS3 exerted potent oncolytic activity against clinical advanced lung adenocarcinoma, which was associated with elevated levels of nuclear YB-1 and cytoplasmic MDR1 expression in the advanced tumors. Therefore, Ad5GS3 may have therapeutic potential for cancer treatment, especially in combination with chemotherapy. Because YB-1 is expressed in a broad spectrum of cancers, this oncolytic adenovirus may be broadly applicable.
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Affiliation(s)
- Bing-Hua Su
- Department of Biochemistry and Molecular Biology, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Gia-Shing Shieh
- Department of Urology, Tainan Hospital, Ministry of Health and Welfare, Executive Yuan, Tainan, Taiwan
| | - Yau-Lin Tseng
- Division of Thoracic Surgery, Department of Surgery, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Ai-Li Shiau
- Department of Microbiology and Immunology, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Chao-Liang Wu
- Department of Biochemistry and Molecular Biology, College of Medicine, National Cheng Kung University, Tainan, Taiwan
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Homma Y, Kanno SI, Sasaki K, Nishita M, Yasui A, Asano T, Ohashi K, Mizuno K. Insulin receptor substrate-4 binds to Slingshot-1 phosphatase and promotes cofilin dephosphorylation. J Biol Chem 2014; 289:26302-26313. [PMID: 25100728 DOI: 10.1074/jbc.m114.565945] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Cofilin plays an essential role in cell migration and morphogenesis by enhancing actin filament dynamics via its actin filament-severing activity. Slingshot-1 (SSH1) is a protein phosphatase that plays a crucial role in regulating actin dynamics by dephosphorylating and reactivating cofilin. In this study, we identified insulin receptor substrate (IRS)-4 as a novel SSH1-binding protein. Co-precipitation assays revealed the direct endogenous binding of IRS4 to SSH1. IRS4, but not IRS1 or IRS2, was bound to SSH1. IRS4 was bound to SSH1 mainly through the unique region (amino acids 335-400) adjacent to the C terminus of the phosphotyrosine-binding domain of IRS4. The N-terminal A, B, and phosphatase domains of SSH1 were bound to IRS4 independently. Whereas in vitro phosphatase assays revealed that IRS4 does not directly affect the cofilin phosphatase activity of SSH1, knockdown of IRS4 increased cofilin phosphorylation in cultured cells. Knockdown of IRS4 decreased phosphatidylinositol 3-kinase (PI3K) activity, and treatment with an inhibitor of PI3K increased cofilin phosphorylation. Akt preferentially phosphorylated SSH1 at Thr-826, but expression of a non-phosphorylatable T826A mutant of SSH1 did not affect insulin-induced cofilin dephosphorylation, and an inhibitor of Akt did not increase cofilin phosphorylation. These results suggest that IRS4 promotes cofilin dephosphorylation through sequential activation of PI3K and SSH1 but not through Akt. In addition, IRS4 co-localized with SSH1 in F-actin-rich membrane protrusions in insulin-stimulated cells, which suggests that the association of IRS4 with SSH1 contributes to localized activation of cofilin in membrane protrusions.
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Affiliation(s)
- Yuta Homma
- Department of Biomolecular Sciences, Graduate School of Life Sciences, Tohoku University, Sendai, Miyagi 980-8578, Japan
| | - Shin-Ichiro Kanno
- Division of Dynamic Proteome in Cancer and Aging, Institute of Development, Aging and Cancer, Tohoku University, Sendai, Miyagi 980-8575, Japan, and
| | - Kazutaka Sasaki
- Department of Biomolecular Sciences, Graduate School of Life Sciences, Tohoku University, Sendai, Miyagi 980-8578, Japan
| | - Michiru Nishita
- Department of Biomolecular Sciences, Graduate School of Life Sciences, Tohoku University, Sendai, Miyagi 980-8578, Japan
| | - Akira Yasui
- Division of Dynamic Proteome in Cancer and Aging, Institute of Development, Aging and Cancer, Tohoku University, Sendai, Miyagi 980-8575, Japan, and
| | - Tomoichiro Asano
- Department of Medical Science, Graduate School of Medicine, University of Hiroshima, Hiroshima, Hiroshima 734-8553, Japan
| | - Kazumasa Ohashi
- Department of Biomolecular Sciences, Graduate School of Life Sciences, Tohoku University, Sendai, Miyagi 980-8578, Japan
| | - Kensaku Mizuno
- Department of Biomolecular Sciences, Graduate School of Life Sciences, Tohoku University, Sendai, Miyagi 980-8578, Japan,.
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Hoxhaj G, Dissanayake K, MacKintosh C. Effect of IRS4 levels on PI 3-kinase signalling. PLoS One 2013; 8:e73327. [PMID: 24039912 PMCID: PMC3769281 DOI: 10.1371/journal.pone.0073327] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2013] [Accepted: 07/25/2013] [Indexed: 11/20/2022] Open
Abstract
Insulin receptor substrate 1 (IRS1) and IRS2 are well-characterized adapter proteins that relay signals from receptor tyrosine kinases to downstream components of signalling pathways. In contrast, the function of IRS4 is not well understood. IRS4 overexpression has been associated with acute lymphoblastic leukaemia and subungual exostosis, while point mutations of IRS4 have been found in melanomas. Here, we show that while IRS4 expression is low in most cancer cell lines, IRS4 mRNA and protein levels are markedly elevated in certain cells including the NCI-H720, DMS114, HEK293T and HEK293AAV lines. Surprisingly, IRS4 expression was also strongly induced when HEK293 cells were infected with retroviral particles and selected under puromycin, making IRS4 expression a potential off-target effect of retroviral expression vectors. Cells with high expression of IRS4 displayed high phosphatidylinositol (3,4,5)-trisphosphate (PIP3) levels, as well as elevated Akt and p70 S6 kinase activities, even in the absence of growth factors. PI 3-kinase (PI3K) signalling in these cells depends on IRS4, even though these cells also express IRS1/2. Knockdown of IRS4 also inhibited cell proliferation in cells with high levels of IRS4. Together, these findings suggest IRS4 as a potential therapeutic target for cancers with high expression of this protein.
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Affiliation(s)
- Gerta Hoxhaj
- Medical Research Council Protein Phosphorylation Unit, College of Life Sciences, University of Dundee, Dundee, Scotland, United Kingdom
- * E-mail: (GH); (CM)
| | - Kumara Dissanayake
- Division of Cell and Developmental Biology, College of Life Sciences, University of Dundee, Dundee, Scotland, United Kingdom
| | - Carol MacKintosh
- Medical Research Council Protein Phosphorylation Unit, College of Life Sciences, University of Dundee, Dundee, Scotland, United Kingdom
- Division of Cell and Developmental Biology, College of Life Sciences, University of Dundee, Dundee, Scotland, United Kingdom
- * E-mail: (GH); (CM)
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Berhane S, Aresté C, Ablack JN, Ryan GB, Blackbourn DJ, Mymryk JS, Turnell AS, Steele JC, Grand RJA. Adenovirus E1A interacts directly with, and regulates the level of expression of, the immunoproteasome component MECL1. Virology 2011; 421:149-58. [PMID: 22018786 DOI: 10.1016/j.virol.2011.09.025] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2011] [Revised: 07/29/2011] [Accepted: 09/27/2011] [Indexed: 10/16/2022]
Abstract
Proteasomes represent the major non-lysosomal mechanism responsible for the degradation of proteins. Following interferon γ treatment 3 proteasome subunits are replaced producing immunoproteasomes. Adenovirus E1A interacts with components of the 20S and 26S proteasome and can affect presentation of peptides. In light of these observations we investigated the relationship of AdE1A to the immunoproteasome. AdE1A interacts with the immunoproteasome subunit, MECL1. In contrast, AdE1A binds poorly to the proteasome β2 subunit which is replaced by MECL1 in the conversion of proteasomes to immunoproteasomes. Binding sites on E1A for MECL1 correspond to the N-terminal region and conserved region 3. Furthermore, AdE1A causes down-regulation of MECL1 expression, as well as LMP2 and LMP7, induced by interferon γ treatment during Ad infections or following transient transfection. Consistent with previous reports AdE1A reduced IFNγ-stimulated STAT1 phosphorylation which appeared to be responsible for its ability to reduce expression of immunoproteasome subunits.
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Affiliation(s)
- Sarah Berhane
- Cancer Research UK, School of Cancer Sciences, University of Birmingham, Birmingham B15 2TT, UK
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Overexpressing cellular repressor of E1A-stimulated genes protects mesenchymal stem cells against hypoxia- and serum deprivation-induced apoptosis by activation of PI3K/Akt. Apoptosis 2010; 15:463-73. [PMID: 19997978 DOI: 10.1007/s10495-009-0434-7] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Bone marrow-derived mesenchymal stem cells (MSCs) have great potential for repair after myocardial infarction. However, poor viability of transplanted MSCs in the ischemic heart has limited their therapeutic potential. Cellular repressor of E1A-stimulated genes (CREG) has been identified as a potent inhibitor of apoptosis. The aim of this study was to investigate the anti-apoptotic effects of CREG on MSCs under hypoxic and serum deprivation (SD) conditions. We also investigated the potential mechanism(s) that may mediate the actions of CREG. All experiments were performed on rat bone marrow MSCs. Apoptosis was induced by exposure of cells to hypoxia/SD in a sealed GENbox hypoxic chamber. Effects of CREG were investigated in the absence or presence of inhibitors that target phosphoinositide 3-kinase (PI3K). We found that the overexpression of CREG markedly protected MSCs from hypoxia/SD-induced apoptosis through inhibition of the mitochondrial apoptotic pathway, leading to attenuation of caspase-3. Moreover, CREG enhanced Akt phosphorylation and decreased the expression of p53 in MSCs under hypoxic/SD conditions. The PI3K/Akt inhibitor LY294002 significantly increased the amount of p53 protein and attenuated the anti-apoptotic effects of CREG on MSCs. This study indicates that CREG is a novel and potent survival factor for MSCs, therefore, it may be a useful therapeutic adjunct for transplanting MSCs into damaged heart after myocardial infarction.
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Lam YW, Evans VC, Heesom KJ, Lamond AI, Matthews DA. Proteomics analysis of the nucleolus in adenovirus-infected cells. Mol Cell Proteomics 2009; 9:117-30. [PMID: 19812395 PMCID: PMC2808258 DOI: 10.1074/mcp.m900338-mcp200] [Citation(s) in RCA: 97] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Adenoviruses replicate primarily in the host cell nucleus, and it is well
established that adenovirus infection affects the structure and function of host
cell nucleoli in addition to coding for a number of nucleolar targeted viral
proteins. Here we used unbiased proteomics methods, including high throughput
mass spectrometry coupled with stable isotope labeling by amino acids in cell
culture (SILAC) and traditional two-dimensional gel electrophoresis, to identify
quantitative changes in the protein composition of the nucleolus during
adenovirus infection. Two-dimensional gel analysis revealed changes in six
proteins. By contrast, SILAC-based approaches identified 351 proteins with 24
proteins showing at least a 2-fold change after infection. Of those, four were
previously reported to have aberrant localization and/or functional relevance
during adenovirus infection. In total, 15 proteins identified as changing in
amount by proteomics methods were examined in infected cells using confocal
microscopy. Eleven of these proteins showed altered patterns of localization in
adenovirus-infected cells. Comparing our data with the effects of actinomycin D
on the nucleolar proteome revealed that adenovirus infection apparently
specifically targets a relatively small subset of nucleolar antigens at the time
point examined.
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Affiliation(s)
- Yun W Lam
- Department of Biology and Chemistry, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon Tong, Hong Kong, China
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15
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Mardilovich K, Pankratz SL, Shaw LM. Expression and function of the insulin receptor substrate proteins in cancer. Cell Commun Signal 2009; 7:14. [PMID: 19534786 PMCID: PMC2709114 DOI: 10.1186/1478-811x-7-14] [Citation(s) in RCA: 129] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2009] [Accepted: 06/17/2009] [Indexed: 12/13/2022] Open
Abstract
The Insulin Receptor Substrate (IRS) proteins are cytoplasmic adaptor proteins that function as essential signaling intermediates downstream of activated cell surface receptors, many of which have been implicated in cancer. The IRS proteins do not contain any intrinsic kinase activity, but rather serve as scaffolds to organize signaling complexes and initiate intracellular signaling pathways. As common intermediates of multiple receptors that can influence tumor progression, the IRS proteins are positioned to play a pivotal role in regulating the response of tumor cells to many different microenvironmental stimuli. Limited studies on IRS expression in human tumors and studies on IRS function in human tumor cell lines and in mouse models have provided clues to the potential function of these adaptor proteins in human cancer. A general theme arises from these studies; IRS-1 and IRS-4 are most often associated with tumor growth and proliferation and IRS-2 is most often associated with tumor motility and invasion. In this review, we discuss the mechanisms by which IRS expression and function are regulated and how the IRS proteins contribute to tumor initiation and progression.
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Affiliation(s)
- Katerina Mardilovich
- Department of Cancer Biology, University of Massachusetts Medical School, Worcester, Massachusetts 01605, USA.
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16
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Venturini L, You J, Stadler M, Galien R, Lallemand V, Koken MH, Mattei MG, Ganser A, Chambon P, Losson R, de Thé H. TIF1gamma, a novel member of the transcriptional intermediary factor 1 family. Oncogene 1999; 32:4622-33. [PMID: 23160376 PMCID: PMC3882591 DOI: 10.1038/onc.2012.501] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2012] [Revised: 09/20/2012] [Accepted: 09/21/2012] [Indexed: 12/23/2022]
Abstract
The Anaphase-Promoting Complex/Cyclosome (APC/C) is an ubiquitin ligase that functions during mitosis. Here we identify the transcriptional regulator, Transcriptional Intermediary Factor 1γ, TIF1γ as an APC/C-interacting protein that regulates APC/C function. TIF1γ is not a substrate for APC/C-dependent ubiquitylation but instead, associates specifically with the APC/C holoenzyme and Cdc20 to affect APC/C activity and progression through mitosis. RNA interference studies indicate that TIF1γ knockdown results in a specific reduction in APC/C ubiquitin ligase activity, the stabilization of APC/C substrates, and an increase in the time taken for cells to progress through mitosis from nuclear envelope breakdown (NEBD) to anaphase. TIF1γ knockdown cells are also characterized by the inappropriate presence of cyclin A at metaphase, and an increase in the number of cells that fail to undergo metaphase-to-anaphase transition. Expression of a siRNA-resistant TIF1γ species relieves the mitotic phenotype imposed by TIF1γ knockdown and allows for mitotic progression. Binding studies indicate that TIF1γ is also a component of the APC/C-Mitotic Checkpoint Complex (MCC), but is not required for MCC dissociation from the APC/C once the Spindle Assembly Checkpoint (SAC) is satisfied. TIF1γ inactivation also results in chromosome misalignment at metaphase, and SAC activation; inactivation of the SAC relieves the mitotic block imposed by TIF1γ knockdown. Together these data define novel functions for TIF1γ during mitosis and suggest that a reduction in APC/C ubiquitin ligase activity promotes SAC activation.
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Affiliation(s)
- L Venturini
- Centre National de la Recherche Scientifique, Unité Propre de Recherche 9051, Laboratoire Associé au Comité de Paris de la Ligue contre le Cancer, Hôpital St. Louis, France
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