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Hinton SD. Understanding Pseudophosphatase Function Through Biochemical Interactions. Methods Mol Biol 2024; 2743:21-41. [PMID: 38147206 DOI: 10.1007/978-1-0716-3569-8_2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2023]
Abstract
Pseudophosphatases have been solidified as important signaling molecules that regulate signal transduction cascades. However, their mechanisms of action remain enigmatic. Reflecting this mystery, the prototypical pseudophosphatase STYX (phospho-serine-threonine/tyrosine-binding protein) was named with allusion to the river of the dead in Greek mythology to emphasize that these molecules are "dead" phosphatases. Although proteins with STYX domains do not catalyze dephosphorylation, this does not preclude their having other functions, including as integral elements of signaling networks. Thus, understanding their roles may mark them as potential novel drug targets. This chapter outlines common strategies used to characterize the functions of pseudophosphatases, using as an example MK-STYX [MAPK (mitogen-activated protein kinase) phospho-serine-threonine/tyrosine-binding], which has been linked to tumorigenesis, hepatocellular carcinoma, glioblastoma, apoptosis, and neuronal differentiation. We start with the importance of "restoring" (when possible) phosphatase activity in a pseudophosphatase, so the active mutant may be used as a comparison control throughout immunoprecipitation and mass spectrometry analyses. To this end, we provide protocols for site-directed mutagenesis, mammalian cell transfection, co-immunoprecipitation, phosphatase activity assays, and immunoblotting that we have used to investigate MK-STYX and the active mutant MK-STYXactive. We also highlight the importance of utilizing RNA interference (RNAi) "knockdown" technology to determine a cellular phenotype in various cell lines. Therefore, we outline our protocols for introducing short hairpin RNA (shRNA) expression plasmids into mammalian cells and quantifying knockdown of gene expression with real-time quantitative PCR (qPCR). We also provide a bioinformatic approach to investigating MK-STYX and MK-STYX(active mutant). These bioinformatic approaches can stand alone experimentally but also complement and enhance "wet" bench approaches such as binding assays and/or activity assays. A combination of cellular, molecular, biochemical, proteomic, and bioinformatic techniques has been a powerful tool in identifying novel functions of MK-STYX. Likewise, the information provided here should be a helpful guide to elucidating the functions of other pseudophosphatases.
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Affiliation(s)
- Shantá D Hinton
- Department of Biology, College of William and Mary, Williamsburg, VA, USA.
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2
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Tian L, Guo T, Wu F, Bai R, Ai S, Wang H, Song Y, Zhu M, Jiang Y, Ma S, Zhuang X, Guo S. The pseudoenzyme ADPRHL1 affects cardiac function by regulating the ROCK pathway. Stem Cell Res Ther 2023; 14:309. [PMID: 37880701 PMCID: PMC10601310 DOI: 10.1186/s13287-023-03507-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Accepted: 09/21/2023] [Indexed: 10/27/2023] Open
Abstract
BACKGROUND Pseudoenzymes, catalytically deficient variants of active enzymes, have a wide range of regulatory functions. ADP-ribosylhydrolase-like 1 (ADPRHL1), a pseudoenzyme belonging to a small group of ADP-ribosylhydrolase enzymes that lacks the amino acid residues necessary for catalytic activity, may have a significant role in heart development based on accumulating evidence. However, the specific function of ADPRHL1 in this process has not been elucidated. To investigate the role of ADPRHL1 in the heart, we generated the first in vitro human embryonic stem cell model with an ADPRHL1 knockout. METHOD Using the CRISPR/Cas9 system, we generated ADPRHL1 knockout in the human embryonic stem cell (hESC) H9 line. The cells were differentiated into cardiomyocytes using a chemically defined and xeno-free method. We employed confocal laser microscopy to detect calcium transients and microelectrode array (MEA) to assess the electrophysiological activity of ADPRHL1 deficiency cardiomyocytes. Additionally, we investigated the cellular mechanism of ADPRHL1 by Bulk RNA sequencing and western blot. RESULTS The results indicate that the absence of ADPRHL1 in cardiomyocytes led to adhered abnormally, as well as perturbations in calcium transients and electrophysiological activity. We also revealed that disruption of focal adhesion formation in these cardiomyocytes was due to an excessive upregulation of the ROCK-myosin II pathway. Notably, inhibition of ROCK and myosin II effectively restores focal adhesions in ADPRHL1-deficient cardiomyocytes and improved electrical conduction and calcium activity. CONCLUSIONS Our findings demonstrate that ADPRHL1 plays a critical role in maintaining the proper function of cardiomyocytes by regulating the ROCK-myosin II pathway, suggesting that it may serve as a potential drug target for the treatment of ADPRHL1-related diseases.
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Affiliation(s)
- Lei Tian
- School of Traditional Chinese Medicine, Beijing University of Chinese Medicine, Beijing, 100029, China
- Department of Nephrology, Beijing Hospital of Traditional Chinese Medicine, Capital Medical University, 23 Meishuguanhou Street, Dongcheng District, Beijing, 100010, China
| | - Tianwei Guo
- Beijing Laboratory for Cardiovascular Precision Medicine, The Key Laboratory of Biomedical Engineering for Cardiovascular Disease Research, Ministry of Education, Beijing Anzhen Hospital, Capital Medical University, Beijing, 100029, China
| | - Fujian Wu
- Translational Medicine Collaborative Innovation Center, The Second Clinical Medical College (Shenzhen People's Hospital), Jinan University, Shenzhen, 518020, China
- Post-Doctoral Scientific Research Station of Basic Medicine, Jinan University, Guangzhou, 510632, China
| | - Rui Bai
- Fuwai Hospital Chinese Academy of Medical Sciences, Shenzhen, 518057, Guangdong Province, China
| | - Sinan Ai
- School of Traditional Chinese Medicine, Beijing University of Chinese Medicine, Beijing, 100029, China
| | - Hongyue Wang
- Department of Cardiology, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Fuwai Hospital, Beilishi Rd 167, Xicheng District, Beijing City, 100037, China
| | - Yuanxiu Song
- Department of Emergency, The First Affiliated Hospital, Zhejiang University School of Medicine, Zhejiang, 310003, China
| | - Min Zhu
- Department of Cardiology, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Fuwai Hospital, Beilishi Rd 167, Xicheng District, Beijing City, 100037, China
| | - Youxu Jiang
- Department of Cardiology, The Second Affiliated Hospital of Zhengzhou University, Jingba Road, Zhengzhou, 450053, China
| | - Shuhong Ma
- Department of Cardiology, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Fuwai Hospital, Beilishi Rd 167, Xicheng District, Beijing City, 100037, China
| | - Xiaofeng Zhuang
- Department of Cardiology, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Fuwai Hospital, Beilishi Rd 167, Xicheng District, Beijing City, 100037, China.
| | - Shuzhen Guo
- School of Traditional Chinese Medicine, Beijing University of Chinese Medicine, Beijing, 100029, China.
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3
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Chakraborty S, Bhat AM, Mushtaq I, Luan H, Kalluchi A, Mirza S, Storck MD, Chaturvedi N, Lopez-Guerrero JA, Llombart-Bosch A, Machado I, Scotlandi K, Meza JL, Ghosal G, Coulter DW, Jordan Rowley M, Band V, Mohapatra BC, Band H. EHD1-dependent traffic of IGF-1 receptor to the cell surface is essential for Ewing sarcoma tumorigenesis and metastasis. Commun Biol 2023; 6:758. [PMID: 37474760 PMCID: PMC10359273 DOI: 10.1038/s42003-023-05125-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Accepted: 07/10/2023] [Indexed: 07/22/2023] Open
Abstract
Overexpression of the EPS15 Homology Domain containing 1 (EHD1) protein has been linked to tumorigenesis but whether its core function as a regulator of intracellular traffic of cell surface receptors plays a role in oncogenesis remains unknown. We establish that EHD1 is overexpressed in Ewing sarcoma (EWS), with high EHD1 mRNA expression specifying shorter patient survival. ShRNA-knockdown and CRISPR-knockout with mouse Ehd1 rescue established a requirement of EHD1 for tumorigenesis and metastasis. RTK antibody arrays identified IGF-1R as a target of EHD1 regulation in EWS. Mechanistically, we demonstrate a requirement of EHD1 for endocytic recycling and Golgi to plasma membrane traffic of IGF-1R to maintain its surface expression and downstream signaling. Conversely, EHD1 overexpression-dependent exaggerated oncogenic traits require IGF-1R expression and kinase activity. Our findings define the RTK traffic regulation as a proximal mechanism of EHD1 overexpression-dependent oncogenesis that impinges on IGF-1R in EWS, supporting the potential of IGF-1R and EHD1 co-targeting.
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Affiliation(s)
- Sukanya Chakraborty
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE, 68198, USA
- Department of Genetics, Cell Biology & Anatomy, College of Medicine, University of Nebraska Medical Center, Omaha, NE, 68198, USA
| | - Aaqib M Bhat
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE, 68198, USA
- Department of Genetics, Cell Biology & Anatomy, College of Medicine, University of Nebraska Medical Center, Omaha, NE, 68198, USA
| | - Insha Mushtaq
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE, 68198, USA
- Incyte Corporation, Wilmington, DE, USA
| | - Haitao Luan
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE, 68198, USA
| | - Achyuth Kalluchi
- Department of Genetics, Cell Biology & Anatomy, College of Medicine, University of Nebraska Medical Center, Omaha, NE, 68198, USA
| | - Sameer Mirza
- Department of Genetics, Cell Biology & Anatomy, College of Medicine, University of Nebraska Medical Center, Omaha, NE, 68198, USA
- Department of Chemistry, College of Science, United Arab Emirates University, Al Ain, UAE
| | - Matthew D Storck
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE, 68198, USA
| | - Nagendra Chaturvedi
- Department of Pediatrics, University of Nebraska Medical Center, Omaha, NE, 68198, USA
| | | | - Antonio Llombart-Bosch
- Department of Pathology, University of Valencia, Avd. Blasco Ibáñez 15, 46010, Valencia, Spain
| | - Isidro Machado
- Department of Pathology, University of Valencia, Avd. Blasco Ibáñez 15, 46010, Valencia, Spain
| | - Katia Scotlandi
- Laboratory of Experimental Oncology, IRCCS Istituto Ortopedico Rizzoli, Bologna, Italy
| | - Jane L Meza
- Department of Biostatistics, College of Public Health, University of Nebraska Medical Center, Omaha, NE, 68198, USA
- Fred & Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE, 68198, USA
| | - Gargi Ghosal
- Department of Genetics, Cell Biology & Anatomy, College of Medicine, University of Nebraska Medical Center, Omaha, NE, 68198, USA
- Fred & Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE, 68198, USA
| | - Donald W Coulter
- Department of Pediatrics, University of Nebraska Medical Center, Omaha, NE, 68198, USA
- Fred & Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE, 68198, USA
| | - M Jordan Rowley
- Department of Genetics, Cell Biology & Anatomy, College of Medicine, University of Nebraska Medical Center, Omaha, NE, 68198, USA
- Fred & Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE, 68198, USA
| | - Vimla Band
- Department of Genetics, Cell Biology & Anatomy, College of Medicine, University of Nebraska Medical Center, Omaha, NE, 68198, USA
- Fred & Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE, 68198, USA
| | - Bhopal C Mohapatra
- Department of Genetics, Cell Biology & Anatomy, College of Medicine, University of Nebraska Medical Center, Omaha, NE, 68198, USA.
- Fred & Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE, 68198, USA.
| | - Hamid Band
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE, 68198, USA.
- Department of Genetics, Cell Biology & Anatomy, College of Medicine, University of Nebraska Medical Center, Omaha, NE, 68198, USA.
- Department of Biostatistics, College of Public Health, University of Nebraska Medical Center, Omaha, NE, 68198, USA.
- Fred & Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE, 68198, USA.
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Zota V, Siegal GP, Kelly D, Bridge JA, Berglund A, Bui K, Khalil F, R Reed D, Altiok S, Magliocco A, Bui MM. Validation of PRKCB Immunohistochemistry as a Biomarker for the Diagnosis of Ewing Sarcoma. Fetal Pediatr Pathol 2023; 42:241-252. [PMID: 36062956 DOI: 10.1080/15513815.2022.2117579] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Background: Ewing sarcoma (ES) can be confirmed by identifying the EWSR1-FLI1 fusion transcript. This study is to investigate whether immunostaining (IHC) of PRKCB-a protein directly regulated by EWSR1-FLI1 is a surrogate maker for diagnosing ES in routine practice. Methods: Microarray gene expression analyses were conducted. RKCB IHC was applied to 69 ES confirmed by morphology and molecular methods, and 41 non-Ewing small round cell tumors. EWSR1 rearrangement, EWSR1-FLI1 fusion or t(11;22)(q24;q12) were identified by fluorescence in situ hybridization, reverse transcriptase polymerase chain reaction, or cytogenetic analysis, respectively. Results: Gene array analyses showed significant overexpression of the PRKCB in ES. PRKCB IHC was positive in 19 cases of ES with EWSR1-FLI1 fusion, 3 cases with cytogenetic 11:22 translocation and 59 cases with EWSR1 rearrangement while negative in only one EWSR1 rearranged case. PRKCB IHC is sensitive (98%) and specific (96%) in detecting EWSR1 rearranged ES. Conclusions: PRKCB is a reliable antibody for diagnosing ES in routine practice.
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Affiliation(s)
- Victor Zota
- Department of Pathology, H. Lee Moffitt Cancer Center and Research Center, Tampa, FL, USA
| | - Gene P Siegal
- Department of Pathology, University of Alabama at Birmingham, Birmingham, AL, USA
- Department of Genetics, University of Alabama at Birmingham, Birmingham, AL, USA
| | - David Kelly
- Department of Pathology and Laboratory, Children's of Alabama, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Julia A Bridge
- Molecular Pathology, ProPath, Dallas, TX, USA
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE, USA
| | - Anders Berglund
- Biostatistics and Bioinformatics Core, H. Lee Moffitt Cancer Center and Research Center, Tampa, FL, USA
| | - Katherine Bui
- Department of Pathology, H. Lee Moffitt Cancer Center and Research Center, Tampa, FL, USA
| | - Farah Khalil
- Department of Pathology, H. Lee Moffitt Cancer Center and Research Center, Tampa, FL, USA
| | - Damon R Reed
- Department of Individualized Cancer Management, H. Lee Moffitt Cancer Center and Research Center, Tampa, FL, USA
| | - Soner Altiok
- Department of Pathology, H. Lee Moffitt Cancer Center and Research Center, Tampa, FL, USA
| | - Anthony Magliocco
- Department of Pathology, H. Lee Moffitt Cancer Center and Research Center, Tampa, FL, USA
| | - Marilyn M Bui
- Department of Pathology, H. Lee Moffitt Cancer Center and Research Center, Tampa, FL, USA
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Chakraborty S, Bhat AM, Mushtaq I, Luan H, Kalluchi A, Mirza S, Storck MD, Chaturvedi N, Lopez-Guerrero JA, Llombart-Bosch A, Machado I, Scotlandi K, Meza JL, Ghosal G, Coulter DW, Rowley JM, Band V, Mohapatra BC, Band H. EHD1-dependent traffic of IGF-1 receptor to the cell surface is essential for Ewing sarcoma tumorigenesis and metastasis. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.15.524130. [PMID: 36711452 PMCID: PMC9882098 DOI: 10.1101/2023.01.15.524130] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Overexpression of EPS15 Homology Domain containing 1 (EHD1) has been linked to tumorigenesis but whether its core function as a regulator of intracellular traffic of cell surface receptors plays a role in oncogenesis remains unknown. We establish that EHD1 is overexpressed in Ewing sarcoma (EWS), with high EHD mRNA expression specifying shorter patient survival. ShRNA and CRISPR-knockout with mouse Ehd1 rescue established a requirement of EHD1 for tumorigenesis and metastasis. RTK antibody arrays identified the IGF-1R as a target of EHD1 regulation in EWS. Mechanistically, we demonstrate a requirement of EHD1 for endocytic recycling and Golgi to plasma membrane traffic of IGF-1R to maintain its surface expression and downstream signaling. Conversely, EHD1 overexpression-dependent exaggerated oncogenic traits require IGF-1R expression and kinase activity. Our findings define the RTK traffic regulation as a proximal mechanism of EHD1 overexpression-dependent oncogenesis that impinges on IGF-1R in EWS, supporting the potential of IGF-1R and EHD1 co-targeting.
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6
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Chen S, Yu W, Li Z, Wang Y, Peng B. STYXL1 promotes proliferation and epithelial mesenchymal transition of gastric cancer cells via activating the PI3K/AKT pathway. Mol Cell Toxicol 2023. [DOI: 10.1007/s13273-023-00345-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/28/2023]
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7
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Regulation of EWSR1-FLI1 Function by Post-Transcriptional and Post-Translational Modifications. Cancers (Basel) 2023; 15:cancers15020382. [PMID: 36672331 PMCID: PMC9857208 DOI: 10.3390/cancers15020382] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2022] [Revised: 01/04/2023] [Accepted: 01/04/2023] [Indexed: 01/11/2023] Open
Abstract
Ewing sarcoma is the second most common bone tumor in childhood and adolescence. Currently, first-line therapy includes multidrug chemotherapy with surgery and/or radiation. Although most patients initially respond to chemotherapy, recurrent tumors become treatment refractory. Pathologically, Ewing sarcoma consists of small round basophilic cells with prominent nuclei marked by expression of surface protein CD99. Genetically, Ewing sarcoma is driven by a fusion oncoprotein that results from one of a small number of chromosomal translocations composed of a FET gene and a gene encoding an ETS family transcription factor, with ~85% of tumors expressing the EWSR1::FLI1 fusion. EWSR1::FLI1 regulates transcription, splicing, genome instability and other cellular functions. Although a tumor-specific target, EWSR1::FLI1-targeted therapy has yet to be developed, largely due to insufficient understanding of EWSR1::FLI1 upstream and downstream signaling, and the challenges in targeting transcription factors with small molecules. In this review, we summarize the contemporary molecular understanding of Ewing sarcoma, and the post-transcriptional and post-translational regulatory mechanisms that control EWSR1::FLI1 function.
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8
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Wang S, Huo X, Yang Y, Mo Y, Kollipara RK, Kittler R. Ablation of EWS-FLI1 by USP9X inhibition suppresses cancer cell growth in Ewing sarcoma. Cancer Lett 2023; 552:215984. [PMID: 36330954 DOI: 10.1016/j.canlet.2022.215984] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2022] [Revised: 10/11/2022] [Accepted: 10/24/2022] [Indexed: 11/26/2022]
Abstract
The neomorphic transcription factor EWS-FLI1 is a key driver of Ewing sarcoma. Ablation of EWS-FLI1 may present a promising therapeutic strategy for this malignancy. Here we found that the deubiquitinase, ubiquitin specific peptidase 9 X-linked (USP9X) stabilizes EWS-FLI1 protein expression in Ewing sarcoma. We show that USP9X binds the ETS domain of EWS-FLI1 in Ewing sarcoma cells and deubiquitinates EWS-FLI1 and that USP9X and EWS-FLI1 protein expression is correlated in clinical Ewing sarcoma specimens. We found that treatment of Ewing sarcoma cells with the USP9X inhibitor WP1130 mediates rapid EWS-FLI1 degradation in vitro and in vivo which coincides with reduced growth of Ewing sarcoma cells and tumors. Our results suggest that USP9X might be a potential therapeutic target to mediate EWS-FLI1 depletion in Ewing sarcoma.
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Affiliation(s)
- Shan Wang
- Department of Research, Guangxi Medical University Cancer Hospital, Nanning, Guangxi Zhuang Autonomous Region, China; Eugene McDermott Center for Human Growth and Development, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Xiaofang Huo
- Eugene McDermott Center for Human Growth and Development, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Yiping Yang
- Department of Research, Guangxi Medical University Cancer Hospital, Nanning, Guangxi Zhuang Autonomous Region, China
| | - Yingxi Mo
- Department of Research, Guangxi Medical University Cancer Hospital, Nanning, Guangxi Zhuang Autonomous Region, China
| | - Rahul K Kollipara
- Eugene McDermott Center for Human Growth and Development, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Ralf Kittler
- Eugene McDermott Center for Human Growth and Development, University of Texas Southwestern Medical Center, Dallas, TX, USA; Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center at Dallas, Dallas, TX, USA; Department of Pharmacology, University of Texas Southwestern Medical Center at Dallas, Dallas, TX, USA; Green Center for Reproductive Biology Sciences, University of Texas Southwestern Medical Center at Dallas, Dallas, TX, USA.
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9
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Chong S, Graham TGW, Dugast-Darzacq C, Dailey GM, Darzacq X, Tjian R. Tuning levels of low-complexity domain interactions to modulate endogenous oncogenic transcription. Mol Cell 2022; 82:2084-2097.e5. [PMID: 35483357 DOI: 10.1016/j.molcel.2022.04.007] [Citation(s) in RCA: 74] [Impact Index Per Article: 37.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Revised: 02/14/2022] [Accepted: 04/01/2022] [Indexed: 01/09/2023]
Abstract
Gene activation by mammalian transcription factors (TFs) requires multivalent interactions of their low-complexity domains (LCDs), but how such interactions regulate transcription remains unclear. It has been proposed that extensive LCD-LCD interactions culminating in liquid-liquid phase separation (LLPS) of TFs is the dominant mechanism underlying transactivation. Here, we investigated how tuning the amount and localization of LCD-LCD interactions in vivo affects transcription of endogenous human genes. Quantitative single-cell and single-molecule imaging reveals that the oncogenic TF EWS::FLI1 requires a narrow optimum of LCD-LCD interactions to activate its target genes associated with GGAA microsatellites. Increasing LCD-LCD interactions toward putative LLPS represses transcription of these genes in patient-derived cells. Likewise, ectopically creating LCD-LCD interactions to sequester EWS::FLI1 into a well-documented LLPS compartment, the nucleolus, inhibits EWS::FLI1-driven transcription and oncogenic transformation. Our findings show how altering the balance of LCD-LCD interactions can influence transcriptional regulation and suggest a potential therapeutic strategy for targeting disease-causing TFs.
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Affiliation(s)
- Shasha Chong
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Thomas G W Graham
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Claire Dugast-Darzacq
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA; CIRM Center of Excellence, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Gina M Dailey
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA; CIRM Center of Excellence, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Xavier Darzacq
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA; CIRM Center of Excellence, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Robert Tjian
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA; Howard Hughes Medical Institute, University of California, Berkeley, Berkeley, CA 94720, USA; Li Ka Shing Center for Biomedical & Health Sciences, University of California, Berkeley, Berkeley, CA 94720, USA; CIRM Center of Excellence, University of California, Berkeley, Berkeley, CA 94720, USA.
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10
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Lindén M, Vannas C, Österlund T, Andersson L, Osman A, Escobar M, Fagman H, Ståhlberg A, Åman P. FET fusion oncoproteins interact with BRD4 and SWI/SNF chromatin remodeling complex subtypes in sarcoma. Mol Oncol 2022; 16:2470-2495. [PMID: 35182012 PMCID: PMC9251840 DOI: 10.1002/1878-0261.13195] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Revised: 11/25/2021] [Accepted: 02/17/2022] [Indexed: 11/24/2022] Open
Abstract
FET fusion oncoproteins containing one of the FET (FUS, EWSR1, TAF15) family proteins juxtaposed to alternative transcription‐factor partners are characteristic of more than 20 types of sarcoma and leukaemia. FET oncoproteins bind to the SWI/SNF chromatin remodelling complex, which exists in three subtypes: cBAF, PBAF and GBAF/ncBAF. We used comprehensive biochemical analysis to characterize the interactions between FET oncoproteins, SWI/SNF complexes and the transcriptional coactivator BRD4. Here, we report that FET oncoproteins bind all three main SWI/SNF subtypes cBAF, PBAF and GBAF, and that FET oncoproteins interact indirectly with BRD4 via their shared interaction partner SWI/SNF. Furthermore, chromatin immunoprecipitation sequencing and proteomic analysis showed that FET oncoproteins, SWI/SNF components and BRD4 co‐localize on chromatin and interact with mediator and RNA Polymerase II. Our results provide a possible molecular mechanism for the FET‐fusion‐induced oncogenic transcriptional profiles and may lead to novel therapies targeting aberrant SWI/SNF complexes and/or BRD4 in FET‐fusion‐caused malignancies.
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Affiliation(s)
- Malin Lindén
- Sahlgrenska Center for Cancer Research, Institute of Biomedicine, Department of Laboratory Medicine, Sahlgrenska Academy, University of Gothenburg, Box 425, 40530, Gothenburg, Sweden
| | - Christoffer Vannas
- Sahlgrenska Center for Cancer Research, Institute of Biomedicine, Department of Laboratory Medicine, Sahlgrenska Academy, University of Gothenburg, Box 425, 40530, Gothenburg, Sweden
| | - Tobias Österlund
- Sahlgrenska Center for Cancer Research, Institute of Biomedicine, Department of Laboratory Medicine, Sahlgrenska Academy, University of Gothenburg, Box 425, 40530, Gothenburg, Sweden.,Wallenberg Centre for Molecular and Translational Medicine, University of Gothenburg, Sweden
| | - Lisa Andersson
- Sahlgrenska Center for Cancer Research, Institute of Biomedicine, Department of Laboratory Medicine, Sahlgrenska Academy, University of Gothenburg, Box 425, 40530, Gothenburg, Sweden
| | - Ayman Osman
- Sahlgrenska Center for Cancer Research, Institute of Biomedicine, Department of Laboratory Medicine, Sahlgrenska Academy, University of Gothenburg, Box 425, 40530, Gothenburg, Sweden
| | - Mandy Escobar
- Sahlgrenska Center for Cancer Research, Institute of Biomedicine, Department of Laboratory Medicine, Sahlgrenska Academy, University of Gothenburg, Box 425, 40530, Gothenburg, Sweden
| | - Henrik Fagman
- Sahlgrenska Center for Cancer Research, Institute of Biomedicine, Department of Laboratory Medicine, Sahlgrenska Academy, University of Gothenburg, Box 425, 40530, Gothenburg, Sweden
| | - Anders Ståhlberg
- Sahlgrenska Center for Cancer Research, Institute of Biomedicine, Department of Laboratory Medicine, Sahlgrenska Academy, University of Gothenburg, Box 425, 40530, Gothenburg, Sweden.,Wallenberg Centre for Molecular and Translational Medicine, University of Gothenburg, Sweden.,Region Västra Götaland, Sahlgrenska University Hospital, Department of Clinical Genetics and Genomics, Gothenburg, Sweden
| | - Pierre Åman
- Sahlgrenska Center for Cancer Research, Institute of Biomedicine, Department of Laboratory Medicine, Sahlgrenska Academy, University of Gothenburg, Box 425, 40530, Gothenburg, Sweden
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11
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Pseudophosphatases as Regulators of MAPK Signaling. Int J Mol Sci 2021; 22:ijms222212595. [PMID: 34830476 PMCID: PMC8622459 DOI: 10.3390/ijms222212595] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Revised: 11/17/2021] [Accepted: 11/18/2021] [Indexed: 01/03/2023] Open
Abstract
Mitogen-activated protein kinase (MAPK) signaling pathways are highly conserved regulators of eukaryotic cell function. These enzymes regulate many biological processes, including the cell cycle, apoptosis, differentiation, protein biosynthesis, and oncogenesis; therefore, tight control of the activity of MAPK is critical. Kinases and phosphatases are well established as MAPK activators and inhibitors, respectively. Kinases phosphorylate MAPKs, initiating and controlling the amplitude of the activation. In contrast, MAPK phosphatases (MKPs) dephosphorylate MAPKs, downregulating and controlling the duration of the signal. In addition, within the past decade, pseudoenzymes of these two families, pseudokinases and pseudophosphatases, have emerged as bona fide signaling regulators. This review discusses the role of pseudophosphatases in MAPK signaling, highlighting the function of phosphoserine/threonine/tyrosine-interacting protein (STYX) and TAK1-binding protein (TAB 1) in regulating MAPKs. Finally, a new paradigm is considered for this well-studied cellular pathway, and signal transduction pathways in general.
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12
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Mattei AM, Smailys JD, Hepworth EMW, Hinton SD. The Roles of Pseudophosphatases in Disease. Int J Mol Sci 2021; 22:ijms22136924. [PMID: 34203203 PMCID: PMC8269279 DOI: 10.3390/ijms22136924] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 06/10/2021] [Accepted: 06/24/2021] [Indexed: 01/07/2023] Open
Abstract
The pseudophosphatases, atypical members of the protein tyrosine phosphatase family, have emerged as bona fide signaling regulators within the past two decades. Their roles as regulators have led to a renaissance of the pseudophosphatase and pseudoenyme fields, catapulting interest from a mere curiosity to intriguing and relevant proteins to investigate. Pseudophosphatases make up approximately fourteen percent of the phosphatase family, and are conserved throughout evolution. Pseudophosphatases, along with pseudokinases, are important players in physiology and pathophysiology. These atypical members of the protein tyrosine phosphatase and protein tyrosine kinase superfamily, respectively, are rendered catalytically inactive through mutations within their catalytic active signature motif and/or other important domains required for catalysis. This new interest in the pursuit of the relevant functions of these proteins has resulted in an elucidation of their roles in signaling cascades and diseases. There is a rapid accumulation of knowledge of diseases linked to their dysregulation, such as neuropathies and various cancers. This review analyzes the involvement of pseudophosphatases in diseases, highlighting the function of various role(s) of pseudophosphatases involvement in pathologies, and thus providing a platform to strongly consider them as key therapeutic drug targets.
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13
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Sundara Rajan S, Ludwig KR, Hall KL, Jones TL, Caplen NJ. Cancer biology functional genomics: From small RNAs to big dreams. Mol Carcinog 2020; 59:1343-1361. [PMID: 33043516 PMCID: PMC7702050 DOI: 10.1002/mc.23260] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Accepted: 09/23/2020] [Indexed: 12/14/2022]
Abstract
The year 2021 marks the 20th anniversary of the first publications reporting the discovery of the gene silencing mechanism, RNA interference (RNAi) in mammalian cells. Along with the many studies that delineated the proteins and substrates that form the RNAi pathway, this finding changed our understanding of the posttranscriptional regulation of mammalian gene expression. Furthermore, the development of methods that exploited the RNAi pathway began the technological revolution that eventually enabled the interrogation of mammalian gene function-from a single gene to the whole genome-in only a few days. The needs of the cancer research community have driven much of this progress. In this perspective, we highlight milestones in the development and application of RNAi-based methods to study carcinogenesis. We discuss how RNAi-based functional genetic analysis of exemplar tumor suppressors and oncogenes furthered our understanding of cancer initiation and progression and explore how such studies formed the basis of genome-wide scale efforts to identify cancer or cancer-type specific vulnerabilities, including studies conducted in vivo. Furthermore, we examine how RNAi technologies have revealed new cancer-relevant molecular targets and the implications for cancer of the first RNAi-based drugs. Finally, we discuss the future of functional genetic analysis, highlighting the increasing availability of complementary approaches to analyze cancer gene function.
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Affiliation(s)
- Soumya Sundara Rajan
- Functional Genetics Section, Genetics BranchCenter for Cancer Research, National Cancer Institute, NIHBethesdaMarylandUSA
| | - Katelyn R. Ludwig
- Functional Genetics Section, Genetics BranchCenter for Cancer Research, National Cancer Institute, NIHBethesdaMarylandUSA
| | - Katherine L. Hall
- Functional Genetics Section, Genetics BranchCenter for Cancer Research, National Cancer Institute, NIHBethesdaMarylandUSA
| | - Tamara L. Jones
- Functional Genetics Section, Genetics BranchCenter for Cancer Research, National Cancer Institute, NIHBethesdaMarylandUSA
| | - Natasha J. Caplen
- Functional Genetics Section, Genetics BranchCenter for Cancer Research, National Cancer Institute, NIHBethesdaMarylandUSA
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14
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Hinton SD. Pseudophosphatase MK-STYX: the atypical member of the MAP kinase phosphatases. FEBS J 2020; 287:4221-4231. [PMID: 32472731 DOI: 10.1111/febs.15426] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Revised: 04/25/2020] [Accepted: 05/26/2020] [Indexed: 01/03/2023]
Abstract
The regulation of the phosphorylation of mitogen-activated protein kinases (MAPKs) is essential for cellular processes such as proliferation, differentiation, survival, and death. Mutations within the MAPK signaling cascades are implicated in diseases such as cancer, neurodegenerative disorders, arthritis, obesity, and diabetes. MAPK phosphorylation is controlled by an intricate balance between MAPK kinases (enzymes that add phosphate groups) and MAPK phosphatases (MKPs) (enzymes that remove phosphate groups). MKPs are complex negative regulators of the MAPK pathway that control the amplitude and spatiotemporal regulation of MAPKs. MK-STYX (MAPK phosphoserine/threonine/tyrosine-binding protein) is a member of the MKP subfamily, which lacks the critical histidine and nucleophilic cysteine residues in the active site required for catalysis. MK-STYX does not influence the phosphorylation status of MAPK, but even so it adds to the complexity of signal transduction cascades as a signaling regulator. This review highlights the function of MK-STYX, providing insight into MK-STYX as a signal regulating molecule in the stress response, HDAC 6 dynamics, apoptosis, and neurite differentiation.
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Affiliation(s)
- Shantá D Hinton
- Department of Biology, Integrated Science Center, William & Mary, Williamsburg, VA, USA
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15
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Reiterer V, Pawłowski K, Desrochers G, Pause A, Sharpe HJ, Farhan H. The dead phosphatases society: a review of the emerging roles of pseudophosphatases. FEBS J 2020; 287:4198-4220. [PMID: 32484316 DOI: 10.1111/febs.15431] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Revised: 05/12/2020] [Accepted: 05/27/2020] [Indexed: 12/11/2022]
Abstract
Phosphatases are a diverse family of enzymes, comprising at least 10 distinct protein folds. Like most other enzyme families, many have sequence variations that predict an impairment or loss of catalytic activity classifying them as pseudophosphatases. Research on pseudoenzymes is an emerging area of interest, with new biological functions repurposed from catalytically active relatives. Here, we provide an overview of the pseudophosphatases identified to date in all major phosphatase families. We will highlight the degeneration of the various catalytic sequence motifs and discuss the challenges associated with the experimental determination of catalytic inactivity. We will also summarize the role of pseudophosphatases in various diseases and discuss the major challenges and future directions in this field.
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Affiliation(s)
| | | | - Guillaume Desrochers
- Department of Biochemistry, McGill University, Montréal, QC, Canada.,Goodman Cancer Research Centre, McGill University, Montréal, QC, Canada
| | - Arnim Pause
- Department of Biochemistry, McGill University, Montréal, QC, Canada.,Goodman Cancer Research Centre, McGill University, Montréal, QC, Canada
| | | | - Hesso Farhan
- Institute of Basic Medical Sciences, University of Oslo, Norway
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16
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Hinton SD. The role of pseudophosphatases as signaling regulators. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2018; 1866:167-174. [PMID: 30077638 DOI: 10.1016/j.bbamcr.2018.07.021] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Revised: 07/23/2018] [Accepted: 07/27/2018] [Indexed: 12/13/2022]
Abstract
Pseudophosphatases are atypical members of the protein tyrosine phosphatase superfamily. Mutations within their catalytic signature motif render them catalytically inactive. Despite this lack of catalytic function, pseudophosphatases have been implicated in various diseases such as Charcot Marie-Tooth disorder, cancer, metabolic disorder, and obesity. Moreover, they have roles in various signaling networks such as spermatogenesis, apoptosis, stress response, tumorigenesis, and neurite differentiation. This review highlights the roles of pseudophosphatases as essential regulators in signaling cascades, providing insight into the function of these catalytically inactive enzymes.
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Affiliation(s)
- Shantá D Hinton
- Department of Biology, Integrated Science Center, College of William and Mary, Williamsburg, VA, USA.
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17
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Banks DA, Dahal A, McFarland AG, Flowers BM, Stephens CA, Swack B, Gugssa A, Anderson WA, Hinton SD. MK-STYX Alters the Morphology of Primary Neurons, and Outgrowths in MK-STYX Overexpressing PC-12 Cells Develop a Neuronal Phenotype. Front Mol Biosci 2017; 4:76. [PMID: 29250526 PMCID: PMC5715325 DOI: 10.3389/fmolb.2017.00076] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2017] [Accepted: 11/02/2017] [Indexed: 01/14/2023] Open
Abstract
We previously reported that the pseudophosphatase MK-STYX (mitogen activated kinase phosphoserine/threonine/tyrosine binding protein) dramatically increases the number of what appeared to be primary neurites in rat pheochromocytoma (PC-12) cells; however, the question remained whether these MK-STYX-induced outgrowths were bona fide neurites, and formed synapses. Here, we report that microtubules and microfilaments, components of the cytoskeleton that are involved in the formation of neurites, are present in MK-STYX-induced outgrowths. In addition, in response to nerve growth factor (NGF), MK-STYX-expressing cells produced more growth cones than non-MK-STYX-expressing cells, further supporting a model in which MK-STYX has a role in actin signaling. Furthermore, immunoblot analysis demonstrates that MK-STYX modulates actin expression. Transmission electron microscopy confirmed that MK-STYX-induced neurites form synapses. To determine whether these MK-STYX-induced neurites have pre-synaptic or post-synaptic properties, we used classical markers for axons and dendrites, Tau-1 and MAP2 (microtubule associated protein 2), respectively. MK-STYX induced neurites were dopaminergic and expression of both Tau-1 and MAP2 suggests that they have both axonal and dendritic properties. Further studies in rat hippocampal primary neurons demonstrated that MK-STYX altered their morphology. A significant number of primary neurons in the presence of MK-STYX had more than the normal number of primary neurites. Our data illustrate the novel findings that MK-STYX induces outgrowths in PC-12 cells that fit the criteria for neurites, have a greater number of growth cones, form synapses, and have pre-synaptic and post-synaptic properties. It also highlights that the pseudophosphatase MK-STYX significantly alters the morphology of primary neurons.
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Affiliation(s)
- Dallas A Banks
- Department of Biology, Integrated Science Center, College of William and Mary, Williamsburg, VA, United States
| | - Arya Dahal
- Department of Biology, Integrated Science Center, College of William and Mary, Williamsburg, VA, United States
| | - Alexander G McFarland
- Department of Biology, Integrated Science Center, College of William and Mary, Williamsburg, VA, United States
| | - Brittany M Flowers
- Department of Biology, Integrated Science Center, College of William and Mary, Williamsburg, VA, United States.,National Cancer Institute, National Institutes of Health, Bethesda, MD, United States
| | - Christina A Stephens
- Department of Chemistry, Integrated Science Center, College of William and Mary, Williamsburg, VA, United States
| | - Benjamin Swack
- Department of Biology, Integrated Science Center, College of William and Mary, Williamsburg, VA, United States
| | - Ayele Gugssa
- Department of Biology, Howard University, Washington, DC, United States
| | | | - Shantá D Hinton
- Department of Biology, Integrated Science Center, College of William and Mary, Williamsburg, VA, United States
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18
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Thangaretnam KP, Gopisetty G, Ramanathan P, Rajkumar T. A polypeptide from the junction region sequence of EWS-FLI1 inhibits Ewing's sarcoma cells, interacts with the EWS-FLI1 and partner proteins. Sci Rep 2017; 7:7172. [PMID: 28775288 PMCID: PMC5543137 DOI: 10.1038/s41598-017-07482-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2017] [Accepted: 06/27/2017] [Indexed: 11/25/2022] Open
Abstract
The EWS-FLI1 chimeric protein uniquely expressed in Ewing’s sarcoma has an obligate role in its aetiology. In our previous report we showed that ectopic expression of the DNA sequences form the junction region (a.a 251–280) can inhibit Ewing’s sarcoma cell growth. In the present report, we introduced a peptide (TAT/NLS/EWS-PEP) comprising of thirty amino acids spanning the junction in conjunction with HIV-1-trans-activating (TAT) and nuclear localization signal sequence (NLS). Peptide uptake and localization studies revealed presence of peptide in ~99% of transduced cells and in the nucleus. Peptide transfection induced cytotoxicity relative to untreated and TAT-NLS peptide treated Ewing’s sarcoma cells. The peptide inhibited clonogenicity, cell cycle, bromo-deoxy uridine (BrdU) uptake and invasion capacity of treated cells. The treatment also affected epithelial to mesenchymal transition (EMT) markers and EWS-FLI1 target gene expression levels. Co-immunoprecipitation experiments involving ectopically expressed full-length EWS-FLI1 protein and the peptide revealed an interaction. Additionally, we found that peptide interaction also occurs with the protein-GGAA microsatellite sequences complex known to contain EWS-FLI1. Further, in the pull-down assay, the peptide was found to interact with proteins known to potentially interact with EWS-FLI1. Based on these results we conclude that peptide could be applied in targeting EWS-FLI1 protein.
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Affiliation(s)
| | - Gopal Gopisetty
- Department of Molecular Oncology, Cancer Institute (WIA), Chennai, India.
| | - Priya Ramanathan
- Department of Molecular Oncology, Cancer Institute (WIA), Chennai, India
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19
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Antagonistic roles for STYX pseudophosphatases in neurite outgrowth. Biochem Soc Trans 2017; 45:381-387. [PMID: 28408478 DOI: 10.1042/bst20160273] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Revised: 01/17/2017] [Accepted: 01/20/2017] [Indexed: 12/14/2022]
Abstract
Mitogen-activated protein kinases (MAPKs) are essential players in important neuronal signaling pathways including neuronal development, plasticity, survival, learning, and memory. The inactivation of MAPKs is tightly controlled by MAPK phosphatases (MKPs), which also are important regulators of these neuronal processes. Considering that MAPKs and MKPs are major players in neuronal signaling, it follows that their misregulation is pivotal in neurodegenerative diseases such as Alzheimer's, Huntington's, Parkinson's, and amyotrophic lateral sclerosis. In contrast, the actions of their noncatalytic homologs, or pseudoenzymes, have received minimal attention as important regulators in neuronal signaling pathways and relevant diseases. There is compelling evidence, however, that pseudophosphatases, such as STYX (phospho-serine-threonine/tyrosine-binding protein) and MAPK-STYX (MK-STYX), are integral signaling molecules in regulating pathways involved in neuronal developmental processes such as neurite outgrowth. Here, we discuss how the dynamics of MK-STYX in the stress response pathway imply that this unique member of the MKP subfamily has the potential to have a major role in neuronal signaling. We further compare the actions of STYX in preventing neurite-like outgrowths and MK-STYX in inducing neurite outgrowths. The roles of these pseudophosphatases in neurite outgrowth highlight their emergence as important candidates to investigate in neurodegenerative disorders and diseases.
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20
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Abstract
Pseudophosphatases regulate signal transduction cascades, but their mechanisms of action remain enigmatic. Reflecting this mystery, the prototypical pseudophosphatase STYX (phospho-serine-threonine/tyrosine-binding protein) was named with allusion to the river of the dead in Greek mythology to emphasize that these molecules are "dead" phosphatases. Although proteins with STYX domains do not catalyze dephosphorylation, this in no way precludes their having other functions as integral elements of signaling networks. Thus, understanding their roles in signaling pathways may mark them as potential novel drug targets. This chapter outlines common strategies used to characterize the functions of pseudophosphatases, using as an example MK-STYX [mitogen-activated protein kinase (MAPK) phospho-serine-threonine/tyrosine binding], which has been linked to tumorigenesis, apoptosis, and neuronal differentiation. We start with the importance of "restoring" (when possible) phosphatase activity in a pseudophosphatase so that the active mutant may be used as a comparison control throughout immunoprecipitation and mass spectrometry analyses. To this end, we provide protocols for site-directed mutagenesis, mammalian cell transfection, co-immunoprecipitation, phosphatase activity assays, and immunoblotting that we have used to investigate MK-STYX and the active mutant MK-STYXactive. We also highlight the importance of utilizing RNA interference (RNAi) "knockdown" technology to determine a cellular phenotype in various cell lines. Therefore, we outline our protocols for introducing short hairpin RNA (shRNA) expression plasmids into mammalians cells and quantifying knockdown of gene expression with real-time quantitative PCR (qPCR). A combination of cellular, molecular, biochemical, and proteomic techniques has served as powerful tools in identifying novel functions of the pseudophosphatase MK-STYX. Likewise, the information provided here should be a helpful guide to elucidating the function of other pseudophosphatases.
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Affiliation(s)
- Shantá D Hinton
- Department of Biology, 3045 Integrated Science Center, College of William and Mary, 540 Landrum Dr., Williamsburg, VA, 23187, USA.
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21
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Jiang Y, Ludwig J, Janku F. Targeted therapies for advanced Ewing sarcoma family of tumors. Cancer Treat Rev 2015; 41:391-400. [PMID: 25869102 DOI: 10.1016/j.ctrv.2015.03.008] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2015] [Revised: 03/17/2015] [Accepted: 03/20/2015] [Indexed: 12/30/2022]
Abstract
The prognosis of adolescent and young adult patients battling metastatic Ewing sarcoma family of tumors (ESFT) remains less than 30% despite the development of systemic therapies. In the era of personalized medicine, novel molecular targets have been tested in preclinical or clinical settings in ESFT. In this review, we focus on early clinical and translational research that identified multiple molecular targets, including IGF-1R; mTOR; tyrosine kinase inhibitors; EWS-FLI1-related targets, and others. Overall, novel targeted therapies demonstrated modest efficacy; however pronounced and durable antineoplastic responses have been observed in small subsets of treated patients, for example with IGF-1R antibodies. Identifying outcome-predicting biomarkers and overcoming treatment resistance remain major challenges. Due to the rarity of ESFT, multi-institutional collaboration efforts of clinicians, basic and translational scientists are needed in order to understand biology of therapeutic response or resistance, which can lead to development of novel therapeutic methods and improved patient outcomes.
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Affiliation(s)
- Yunyun Jiang
- Department of Investigational Cancer Therapeutics (Phase I Clinical Trials Program), The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Joseph Ludwig
- Department of Sarcoma Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA.
| | - Filip Janku
- Department of Investigational Cancer Therapeutics (Phase I Clinical Trials Program), The University of Texas MD Anderson Cancer Center, Houston, TX, USA.
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22
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Amaral AT, Garofalo C, Frapolli R, Manara MC, Mancarella C, Uboldi S, Giandomenico SD, Ordóñez JL, Sevillano V, Malaguarnera R, Picci P, Hassan AB, Alava ED, D'Incalci M, Scotlandi K. Trabectedin Efficacy in Ewing Sarcoma Is Greatly Increased by Combination with Anti-IGF Signaling Agents. Clin Cancer Res 2015; 21:1373-82. [DOI: 10.1158/1078-0432.ccr-14-1688] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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23
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The pseudophosphatase MK-STYX induces neurite-like outgrowths in PC12 cells. PLoS One 2014; 9:e114535. [PMID: 25479605 PMCID: PMC4257672 DOI: 10.1371/journal.pone.0114535] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2014] [Accepted: 11/10/2014] [Indexed: 01/17/2023] Open
Abstract
The rat pheochromocytoma PC12 cell line is a widely used system to study neuronal differentiation for which sustained activation of the extracellular signaling related kinase (ERK) pathway is required. Here, we investigate the function of MK-STYX [MAPK (mitogen-activated protein kinase) phosphoserine/threonine/tyrosine-binding protein] in neuronal differentiation. MK-STYX is a member of the MAPK phosphatase (MKP) family, which is generally responsible for dephosphorylating the ERKs. However, MK-STYX lacks catalytic activity due to the absence of the nucleophilic cysteine in the active site signature motif HC(X5)R that is essential for phosphatase activity. Despite being catalytically inactive, MK-STYX has been shown to play a role in important cellular pathways, including stress responses. Here we show that PC12 cells endogenously express MK-STYX. In addition, MK-STYX, but not its catalytically active mutant, induced neurite-like outgrowths in PC12 cells. Furthermore, MK-STYX dramatically increased the number of cells with neurite extensions in response to nerve growth factor (NGF), whereas the catalytically active mutant did not. MK-STYX continued to induce neurites in the presence of a MEK (MAP kinase kinase) inhibitor suggesting that MK-STYX does not act through the Ras-ERK/MAPK pathway but is involved in another pathway whose inactivation leads to neuronal differentiation. RhoA activity assays indicated that MK-STYX induced extensions through the Rho signaling pathway. MK-STYX decreased RhoA activation, whereas RhoA activation increased when MK-STYX was down-regulated. Furthermore, MK-STYX affected downstream players of RhoA such as the actin binding protein cofilin. The presence of MK-STYX decreased the phosphorylation of cofilin in non NGF stimulated cells, but increased its phosphorylation in NGF stimulated cells, whereas knocking down MK-STYX caused an opposite effect. Taken together our data suggest that MK-STYX may be a regulator of RhoA signaling, and implicate this pseudophosphatase as a regulator of neuronal differentiation.
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24
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Niedan S, Kauer M, Aryee DNT, Kofler R, Schwentner R, Meier A, Pötschger U, Kontny U, Kovar H. Suppression of FOXO1 is responsible for a growth regulatory repressive transcriptional sub-signature of EWS-FLI1 in Ewing sarcoma. Oncogene 2014; 33:3927-38. [PMID: 23995784 PMCID: PMC4114138 DOI: 10.1038/onc.2013.361] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2013] [Revised: 06/17/2013] [Accepted: 07/26/2013] [Indexed: 11/09/2022]
Abstract
The Ewing sarcoma (ES) EWS-FLI1 chimeric oncoprotein is a prototypic aberrant ETS transcription factor with activating and repressive regulatory functions. We report that EWS-FLI1-repressed promoters are enriched in forkhead box (FOX) recognition motifs, and identify FOXO1 as a EWS-FLI1-suppressed regulator orchestrating a major subset of EWS-FLI1-repressed genes. In addition to FOXO1 regulation by direct promoter binding of EWS-FLI1, its subcellular localization and activity is regulated by cyclin-dependent kinase 2- and AKT-mediated phosphorylation downstream of EWS-FLI1. Restoration of nuclear FOXO1 expression in ES cells impaired proliferation and significantly reduced clonogenicity. Gene-expression profiling revealed a significant overlap between EWS-FLI1-repressed and FOXO1-activated genes. As a proof of principle for a potential therapeutic application of our findings, the treatment of ES cell lines with methylseleninic acid (MSA) reactivated endogenous FOXO1 in the presence of EWS-FLI1 in a dose- and time-dependent manner and induced massive cell death dependent on FOXO1. In an orthotopic xenograft mouse model, MSA increased FOXO1 expression in the tumor paralleled by a significant decrease in ES tumor growth. FOXO1 reactivation by small molecules may therefore serve as a promising strategy for a future ES-specific therapy.
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MESH Headings
- Animals
- Antineoplastic Agents/pharmacology
- Base Sequence
- Binding Sites
- Bone Neoplasms/drug therapy
- Bone Neoplasms/genetics
- Bone Neoplasms/metabolism
- Cell Line, Tumor
- Cell Proliferation
- Consensus Sequence
- Cyclin-Dependent Kinase 2/metabolism
- Forkhead Box Protein O1
- Forkhead Box Protein O3
- Forkhead Transcription Factors/genetics
- Forkhead Transcription Factors/metabolism
- Gene Expression Regulation, Neoplastic
- Gene Silencing
- Humans
- Mice
- Oncogene Proteins, Fusion/genetics
- Oncogene Proteins, Fusion/metabolism
- Organoselenium Compounds/pharmacology
- Phosphorylation
- Promoter Regions, Genetic
- Protein Processing, Post-Translational
- Protein Transport
- Proto-Oncogene Protein c-fli-1/genetics
- Proto-Oncogene Protein c-fli-1/metabolism
- Proto-Oncogene Proteins c-akt/metabolism
- RNA-Binding Protein EWS/genetics
- RNA-Binding Protein EWS/metabolism
- Sarcoma, Ewing/drug therapy
- Sarcoma, Ewing/genetics
- Sarcoma, Ewing/metabolism
- Transcription, Genetic
- Tumor Burden/drug effects
- Xenograft Model Antitumor Assays
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Affiliation(s)
- S Niedan
- Children's Cancer Research Institute, St Anna Kinderkrebsforschung, Vienna, Austria
| | - M Kauer
- Children's Cancer Research Institute, St Anna Kinderkrebsforschung, Vienna, Austria
| | - D N T Aryee
- Children's Cancer Research Institute, St Anna Kinderkrebsforschung, Vienna, Austria
- Department of Pediatrics, Medical University, Vienna, Austria
| | - R Kofler
- Division of Molecular Pathophysiology, Biocenter, Medical University Innsbruck, Innsbruck, Austria
| | - R Schwentner
- Children's Cancer Research Institute, St Anna Kinderkrebsforschung, Vienna, Austria
| | - A Meier
- Division of Pediatric Hematology and Oncology, Department of Pediatrics and Adolescent Medicine, University Medical Center, Freiburg, Germany
| | - U Pötschger
- Children's Cancer Research Institute, St Anna Kinderkrebsforschung, Vienna, Austria
| | - U Kontny
- Division of Pediatric Hematology and Oncology, Department of Pediatrics and Adolescent Medicine, University Medical Center, Freiburg, Germany
| | - H Kovar
- Children's Cancer Research Institute, St Anna Kinderkrebsforschung, Vienna, Austria
- Department of Pediatrics, Medical University, Vienna, Austria
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25
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Stebbing J, Lit LC, Zhang H, Darrington RS, Melaiu O, Rudraraju B, Giamas G. The regulatory roles of phosphatases in cancer. Oncogene 2014; 33:939-53. [PMID: 23503460 DOI: 10.1038/onc.2013.80] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2013] [Accepted: 02/01/2013] [Indexed: 02/06/2023]
Abstract
The relevance of potentially reversible post-translational modifications required for controlling cellular processes in cancer is one of the most thriving arenas of cellular and molecular biology. Any alteration in the balanced equilibrium between kinases and phosphatases may result in development and progression of various diseases, including different types of cancer, though phosphatases are relatively under-studied. Loss of phosphatases such as PTEN (phosphatase and tensin homologue deleted on chromosome 10), a known tumour suppressor, across tumour types lends credence to the development of phosphatidylinositol 3-kinase inhibitors alongside the use of phosphatase expression as a biomarker, though phase 3 trial data are lacking. In this review, we give an updated report on phosphatase dysregulation linked to organ-specific malignancies.
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Affiliation(s)
- J Stebbing
- Division of Cancer, Department of Surgery and Cancer, Imperial College London, London, UK
| | - L C Lit
- Division of Cancer, Department of Surgery and Cancer, Imperial College London, London, UK
| | - H Zhang
- Division of Cancer, Department of Surgery and Cancer, Imperial College London, London, UK
| | - R S Darrington
- Division of Cancer, Department of Surgery and Cancer, Imperial College London, London, UK
| | - O Melaiu
- Division of Cancer, Department of Surgery and Cancer, Imperial College London, London, UK
| | - B Rudraraju
- Division of Cancer, Department of Surgery and Cancer, Imperial College London, London, UK
| | - G Giamas
- Division of Cancer, Department of Surgery and Cancer, Imperial College London, London, UK
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Kar A, Gutierrez-Hartmann A. Molecular mechanisms of ETS transcription factor-mediated tumorigenesis. Crit Rev Biochem Mol Biol 2013; 48:522-43. [PMID: 24066765 DOI: 10.3109/10409238.2013.838202] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The E26 transformation-specific (ETS) family of transcription factors is critical for development, differentiation, proliferation and also has a role in apoptosis and tissue remodeling. Changes in expression of ETS proteins therefore have a significant impact on normal physiology of the cell. Transcriptional consequences of ETS protein deregulation by overexpression, gene fusion, and modulation by RAS/MAPK signaling are linked to alterations in normal cell functions, and lead to unlimited increased proliferation, sustained angiogenesis, invasion and metastasis. Existing data show that ETS proteins control pathways in epithelial cells as well as stromal compartments, and the crosstalk between the two is essential for normal development and cancer. In this review, we have focused on ETS factors with a known contribution in cancer development. Instead of focusing on a prototype, we address cancer associated ETS proteins and have highlighted the diverse mechanisms by which they affect carcinogenesis. Finally, we discuss strategies for ETS factor targeting as a potential means for cancer therapeutics.
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Ross KA, Smyth NA, Murawski CD, Kennedy JG. The biology of ewing sarcoma. ISRN ONCOLOGY 2013; 2013:759725. [PMID: 23346417 PMCID: PMC3549336 DOI: 10.1155/2013/759725] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 11/14/2012] [Accepted: 12/16/2012] [Indexed: 12/02/2022]
Abstract
Objective. The goal of this study was to review the current literature on the biology of Ewing's sarcoma, including current treatments and the means by which an understanding of biological mechanisms could impact future treatments. Methods. A search of PubMed and The Cochrane Collaboration was performed. Both preclinical and clinical evidence was considered, but specific case reports were not. Primary research articles and reviews were analyzed with an emphasis on recent publications. Results. Ewing sarcoma is associated with specific chromosomal translocations and the resulting transcripts/proteins. Knowledge of the biology of Ewing sarcoma has been growing but has yet to significantly impact or produce new treatments. Localized cases have seen improvements in survival rates, but the same cannot be said of metastatic and recurrent cases. Standard surgical, radiation, and chemotherapy treatments are reaching their efficacy limits. Conclusion. Improving prognosis likely lies in advancing biomarkers and early diagnosis, determining a cell(s) of origin, and developing effective molecular therapeutics and antiangiogenic agents. Preclinical evidence suggests the utility of molecular therapies for Ewing sarcoma. Early clinical results also reveal potential for novel treatments but require further development and evaluation before widespread use can be advocated.
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Affiliation(s)
- Keir A. Ross
- Hospital for Special Surgery, 523 East 72nd Street, Suite 507, New York, NY 10021, USA
| | - Niall A. Smyth
- Hospital for Special Surgery, 523 East 72nd Street, Suite 507, New York, NY 10021, USA
| | | | - John G. Kennedy
- Hospital for Special Surgery, 523 East 72nd Street, Suite 507, New York, NY 10021, USA
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Barr JE, Munyikwa MR, Frazier EA, Hinton SD. The pseudophosphatase MK-STYX inhibits stress granule assembly independently of Ser149 phosphorylation of G3BP-1. FEBS J 2012; 280:273-84. [PMID: 23163895 PMCID: PMC3586659 DOI: 10.1111/febs.12068] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2012] [Revised: 10/28/2012] [Accepted: 11/13/2012] [Indexed: 01/07/2023]
Abstract
The pseudophosphatase MK-STYX (mitogen-activated protein kinase phosphoserine/threonine/tyrosine-binding protein) has been implicated in the stress response pathway. The expression of MK-STYX inhibits the assembly of stress granules, which are cytoplasmic storage sites for mRNA that form as a protective mechanism against stressors such as heat shock, UV irradiation and hypoxia. Furthermore, MK-STYX interacts with a key component of stress granules: G3BP-1 (Ras-GTPase activating protein SH3 domain binding protein-1). Because G3BP-1 dephosphorylation at Ser149 induces stress granule assembly, we initially hypothesized that the inhibition of stress granules by MK-STYX was G3BP-1 phosphorylation-dependent. However, in the present study, using MK-STYX constructs and G3BP-1 phosphomimetic or nonphosphorylatable mutants, we show that MK-STYX inhibits stress granule formation independently of G3BP-1 phosphorylation at Ser149. The introduction of point mutations at the ‘active site’ of MK-STYX that convert serine and phenylalanine to histidine and cysteine, respectively, is sufficient to generate an active enzyme. In separate experiments, we show that this active mutant, MK-STYXactive, has opposite effects to wild-type MK-STYK. Not only does MK-STYXactive induce stress granules, but also it has the capacity to dephosphorylate G3BP-1. Taken together, these results provide evidence that the pseudophosphatase MK-STYX plays a key role in the cellular response to stress.
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Affiliation(s)
- Justinn E Barr
- Department of Biology, Integrated Science Center, College of William and Mary, Williamsburg, VA 23185, USA
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Targeting the EWSR1-FLI1 Oncogene-Induced Protein Kinase PKC-β Abolishes Ewing Sarcoma Growth. Cancer Res 2012; 72:4494-503. [DOI: 10.1158/0008-5472.can-12-0371] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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30
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Brenner JC, Feng FY, Han S, Patel S, Goyal SV, Bou-Maroun LM, Liu M, Lonigro R, Prensner JR, Tomlins SA, Chinnaiyan AM. PARP-1 inhibition as a targeted strategy to treat Ewing's sarcoma. Cancer Res 2012; 72:1608-13. [PMID: 22287547 PMCID: PMC3319786 DOI: 10.1158/0008-5472.can-11-3648] [Citation(s) in RCA: 201] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Ewing's sarcoma family of tumors (ESFT) refers to aggressive malignancies which frequently harbor characteristic EWS-FLI1 or EWS-ERG genomic fusions. Here, we report that these fusion products interact with the DNA damage response protein and transcriptional coregulator PARP-1. ESFT cells, primary tumor xenografts, and tumor metastases were all highly sensitive to PARP1 inhibition. Addition of a PARP1 inhibitor to the second-line chemotherapeutic agent temozolamide resulted in complete responses of all treated tumors in an EWS-FLI1-driven mouse xenograft model of ESFT. Mechanistic investigations revealed that DNA damage induced by expression of EWS-FLI1 or EWS-ERG fusion genes was potentiated by PARP1 inhibition in ESFT cell lines. Notably, EWS-FLI1 fusion genes acted in a positive feedback loop to maintain the expression of PARP1, which was required for EWS-FLI-mediated transcription, thereby enforcing oncogene-dependent sensitivity to PARP-1 inhibition. Together, our findings offer a strong preclinical rationale to target the EWS-FLI1:PARP1 intersection as a therapeutic strategy to improve the treatment of ESFTs.
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Affiliation(s)
- J Chad Brenner
- Michigan Center for Translational Pathology, Department of Pathology, University of Michigan, Ann Arbor, Michigan 48109, USA
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31
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Dai X, Ma W, He X, Jha RK. Review of therapeutic strategies for osteosarcoma, chondrosarcoma, and Ewing's sarcoma. Med Sci Monit 2011; 17:RA177-190. [PMID: 21804475 PMCID: PMC3539609 DOI: 10.12659/msm.881893] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
The most prevalent forms of bone cancer are osteosarcoma, chondrosarcoma, and Ewing’s sarcoma. Although chemotherapy and radiotherapy have replaced traditional surgical treatments, survival rates have undergone only marginal improvements. Current knowledge of the molecular pathways involved in each type of cancer has led to better approaches in cancer treatment. A number of cell signaling molecules are involved in tumorigenesis, and specific targets have been identified based on these signal transducers. This review highlights some of the important cellular pathways and potential therapeutic targets, tumor site-specific irradiation techniques, and novel drug delivery systems used to administer these drugs.
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Affiliation(s)
- Xing Dai
- Department of Orthopedic Surgery, 1st Affiliated Hospital of Xi'an Jiaotong University, Xi'an, China
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32
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Herrero-Martin D, Fourtouna A, Niedan S, Riedmann LT, Schwentner R, Aryee DNT. Factors Affecting EWS-FLI1 Activity in Ewing's Sarcoma. Sarcoma 2011; 2011:352580. [PMID: 22135504 PMCID: PMC3216314 DOI: 10.1155/2011/352580] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2011] [Revised: 08/31/2011] [Accepted: 08/31/2011] [Indexed: 02/06/2023] Open
Abstract
Ewing's sarcoma family tumors (ESFT) are characterized by specific chromosomal translocations, which give rise to EWS-ETS chimeric proteins. These aberrant transcription factors are the main pathogenic drivers of ESFT. Elucidation of the factors influencing EWS-ETS expression and/or activity will guide the development of novel therapeutic agents against this fatal disease.
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Affiliation(s)
- David Herrero-Martin
- Children's Cancer Research Institute, St Anna Kinderkrebsforschung, 1090 Vienna, Austria
| | - Argyro Fourtouna
- Children's Cancer Research Institute, St Anna Kinderkrebsforschung, 1090 Vienna, Austria
| | - Stephan Niedan
- Children's Cancer Research Institute, St Anna Kinderkrebsforschung, 1090 Vienna, Austria
| | - Lucia T. Riedmann
- Children's Cancer Research Institute, St Anna Kinderkrebsforschung, 1090 Vienna, Austria
| | - Raphaela Schwentner
- Children's Cancer Research Institute, St Anna Kinderkrebsforschung, 1090 Vienna, Austria
| | - Dave N. T. Aryee
- Children's Cancer Research Institute, St Anna Kinderkrebsforschung, 1090 Vienna, Austria
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33
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Leacock SW, Basse AN, Chandler GL, Kirk AM, Rakheja D, Amatruda JF. A zebrafish transgenic model of Ewing's sarcoma reveals conserved mediators of EWS-FLI1 tumorigenesis. Dis Model Mech 2011; 5:95-106. [PMID: 21979944 PMCID: PMC3255547 DOI: 10.1242/dmm.007401] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Ewing’s sarcoma, a malignant bone tumor of children and young adults, is a member of the small-round-blue-cell tumor family. Ewing’s sarcoma family tumors (ESFTs), which include peripheral primitive neuroectodermal tumors (PNETs), are characterized by chromosomal translocations that generate fusions between the EWS gene and ETS-family transcription factors, most commonly FLI1. The EWS-FLI1 fusion oncoprotein represents an attractive therapeutic target for treatment of Ewing’s sarcoma. The cell of origin of ESFT and the molecular mechanisms by which EWS-FLI1 mediates tumorigenesis remain unknown, and few animal models of Ewing’s sarcoma exist. Here, we report the use of zebrafish as a vertebrate model of EWS-FLI1 function and tumorigenesis. Mosaic expression of the human EWS-FLI1 fusion protein in zebrafish caused the development of tumors with histology strongly resembling that of human Ewing’s sarcoma. The incidence of tumors increased in a p53 mutant background, suggesting that the p53 pathway suppresses EWS-FLI1-driven tumorigenesis. Gene expression profiling of the zebrafish tumors defined a set of genes that might be regulated by EWS-FLI1, including the zebrafish ortholog of a crucial EWS-FLI1 target gene in humans. Stable zebrafish transgenic lines expressing EWS-FLI1 under the control of the heat-shock promoter exhibit altered embryonic development and defective convergence and extension, suggesting that EWS-FLI1 interacts with conserved developmental pathways. These results indicate that functional targets of EWS-FLI1 that mediate tumorigenesis are conserved from zebrafish to human and provide a novel context in which to study the function of this fusion oncogene.
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Affiliation(s)
- Stefanie W Leacock
- Department of Pediatrics, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX 75390-8534, USA
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Sankar S, Lessnick SL. Promiscuous partnerships in Ewing's sarcoma. Cancer Genet 2011; 204:351-65. [PMID: 21872822 PMCID: PMC3164520 DOI: 10.1016/j.cancergen.2011.07.008] [Citation(s) in RCA: 164] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2011] [Revised: 07/18/2011] [Accepted: 07/19/2011] [Indexed: 12/16/2022]
Abstract
Ewing's sarcoma is a highly aggressive bone and soft tissue tumor of children and young adults. At the molecular genetic level Ewing's sarcoma is characterized by a balanced reciprocal translocation, t(11;22)(q24;q12), which encodes an oncogenic fusion protein and transcription factor EWS/FLI. This tumor-specific chimeric fusion retains the amino terminus of EWS, a member of the TET (TLS/EWS/TAF15) family of RNA-binding proteins, and the carboxy terminus of FLI, a member of the ETS family of transcription factors. In addition to EWS/FLI, variant translocation fusions belonging to the TET/ETS family have been identified in Ewing's sarcoma. These studies solidified the importance of TET/ETS fusions in the pathogenesis of Ewing's sarcoma and have since been used as diagnostic markers for the disease. EWS fusions with non-ETS transcription factor family members have been described in sarcomas that are clearly distinct from Ewing's sarcoma. However, in recent years there have been reports of rare fusions in "Ewing's-like tumors" that harbor the amino-terminus of EWS fused to the carboxy-terminal DNA or chromatin-interacting domains contributed by non-ETS proteins. This review aims to summarize the growing list of fusion oncogenes that characterize Ewing's sarcoma and Ewing's-like tumors and highlights important questions that need to be answered to further support the existing concept that Ewing's sarcoma is strictly a "TET/ETS" fusion-driven malignancy. Understanding the molecular mechanisms of action of the various different fusion oncogenes will provide better insights into the biology underlying this rare but important solid tumor.
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Affiliation(s)
- Savita Sankar
- Department of Oncological Sciences, University of Utah School of Medicine, Salt Lake City, UT, USA 84112
| | - Stephen L. Lessnick
- Department of Oncological Sciences, University of Utah School of Medicine, Salt Lake City, UT, USA 84112
- Center for Children’s Cancer Research at Huntsman Cancer Institute, University of Utah, Salt Lake City, UT, USA 84112
- Division of Pediatric Hematology/Oncology, University of Utah School of Medicine, Salt Lake City, UT
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35
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Reiner JE, Datta PK. TGF-beta-dependent and -independent roles of STRAP in cancer. Front Biosci (Landmark Ed) 2011; 16:105-15. [PMID: 21196161 DOI: 10.2741/3678] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The serine-threonine kinase receptor-associated protein (STRAP) was initially identified as a putative inhibitor of the canonical TGF-beta signaling pathway. Because the Smad-dependent TGF-beta pathway negatively regulates cellular growth, early functional studies suggested that STRAP behaves as an oncogene. Indeed, a correlation between STRAP overexpression and various cancers has been identified. With the emergence of new studies on the biological function of STRAP, it is becoming clear that STRAP regulates several distinct cellular processes and modulates multiple signaling pathways. While STRAP itself does not possess enzymatic activity, it appears that STRAP influences biological processes through associations with cellular proteins. In this review, we will describe the TGF-beta-dependent and -independent functions of STRAP and provide a context for the significance of STRAP activity in the development of cancer.
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Affiliation(s)
- Jennifer Elisabeth Reiner
- Cancer Biology, Vanderbilt-Ingram Cancer Center, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
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36
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Dr. Jekyll and Mr. Hyde: The Two Faces of the FUS/EWS/TAF15 Protein Family. Sarcoma 2010; 2011:837474. [PMID: 21197473 PMCID: PMC3005952 DOI: 10.1155/2011/837474] [Citation(s) in RCA: 93] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2010] [Revised: 10/20/2010] [Accepted: 11/01/2010] [Indexed: 12/13/2022] Open
Abstract
FUS, EWS, and TAF15 form the FET family of RNA-binding proteins whose genes are found rearranged with various transcription factor genes predominantly in sarcomas and in rare hematopoietic and epithelial cancers. The resulting fusion gene products have attracted considerable interest as diagnostic and promising therapeutic targets. So far, oncogenic FET fusion proteins have been regarded as strong transcription factors that aberrantly activate or repress target genes of their DNA-binding fusion partners. However, the role of the transactivating domain in the context of the normal FET proteins is poorly defined, and, therefore, our knowledge on how FET aberrations impact on tumor biology is incomplete. Since we believe that a full understanding of aberrant FET protein function can only arise from looking at both sides of the coin, the good and the evil, this paper summarizes evidence for the central function of FET proteins in bridging RNA transcription, processing, transport, and DNA repair.
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37
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Mesenchymal Stem Cells and the Origin of Ewing's Sarcoma. Sarcoma 2010; 2011. [PMID: 20953407 PMCID: PMC2952797 DOI: 10.1155/2011/276463] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2010] [Accepted: 09/06/2010] [Indexed: 12/17/2022] Open
Abstract
The origin of Ewing's sarcoma is a subject of much debate. Once thought to be derived from primitive neuroectodermal cells, many now believe it to arise from a mesenchymal stem cell (MSC). Expression of the EWS-FLI1 fusion gene in MSCs changes cell morphology to resemble Ewing's sarcoma and induces expression of neuroectodermal markers. In murine cells, transformation to sarcomas can occur. In knockdown experiments, Ewing's sarcoma cells develop characteristics of MSCs and the ability to differentiate into mesodermal lineages. However, it cannot be concluded that MSCs are the cell of origin. The concept of an MSC still needs to be rigorously defined, and there may be different subpopulations of mesenchymal pluripotential cells. Furthermore, EWS-FLI1 by itself does not transform human cells, and cooperating mutations appear to be necessary. Therefore, while it is possible that Ewing's sarcoma may originate from a primitive mesenchymal cell, the idea needs to be refined further.
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Arora S, Gonzales IM, Hagelstrom RT, Beaudry C, Choudhary A, Sima C, Tibes R, Mousses S, Azorsa DO. RNAi phenotype profiling of kinases identifies potential therapeutic targets in Ewing's sarcoma. Mol Cancer 2010; 9:218. [PMID: 20718987 PMCID: PMC2933621 DOI: 10.1186/1476-4598-9-218] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2010] [Accepted: 08/18/2010] [Indexed: 01/12/2023] Open
Abstract
Background Ewing's sarcomas are aggressive musculoskeletal tumors occurring most frequently in the long and flat bones as a solitary lesion mostly during the teen-age years of life. With current treatments, significant number of patients relapse and survival is poor for those with metastatic disease. As part of novel target discovery in Ewing's sarcoma, we applied RNAi mediated phenotypic profiling to identify kinase targets involved in growth and survival of Ewing's sarcoma cells. Results Four Ewing's sarcoma cell lines TC-32, TC-71, SK-ES-1 and RD-ES were tested in high throughput-RNAi screens using a siRNA library targeting 572 kinases. Knockdown of 25 siRNAs reduced the growth of all four Ewing's sarcoma cell lines in replicate screens. Of these, 16 siRNA were specific and reduced proliferation of Ewing's sarcoma cells as compared to normal fibroblasts. Secondary validation and preliminary mechanistic studies highlighted the kinases STK10 and TNK2 as having important roles in growth and survival of Ewing's sarcoma cells. Furthermore, knockdown of STK10 and TNK2 by siRNA showed increased apoptosis. Conclusion In summary, RNAi-based phenotypic profiling proved to be a powerful gene target discovery strategy, leading to successful identification and validation of STK10 and TNK2 as two novel potential therapeutic targets for Ewing's sarcoma.
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Affiliation(s)
- Shilpi Arora
- Pharmaceutical Genomic Division, Translational Genomics Research Institute, Scottsdale, AZ 85259, USA
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Erkizan HV, Uversky VN, Toretsky JA. Oncogenic partnerships: EWS-FLI1 protein interactions initiate key pathways of Ewing's sarcoma. Clin Cancer Res 2010; 16:4077-83. [PMID: 20547696 DOI: 10.1158/1078-0432.ccr-09-2261] [Citation(s) in RCA: 109] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Targeted therapy for cancer, which is specifically directed toward the cancer without any potential for effects outside of controlling the tumor, is a gold standard for treatment. Ewing's sarcoma contains the potential target EWS-FLI1, as a result of a pathognomonic chromosomal translocation. The EWS-FLI1 fusion protein includes the EWS domain, a potent transcriptional activator alongside the highly conserved FLI1 ets DNA-binding domain. Because of the combination of these domains, the EWS-FLI1 fusion protein acts as an aberrant transcription factor whose expression results in cellular transformation. EWS-FLI1 functions by binding to normal cellular protein partners in transcription and splicing, similar to how a virus would corrupt normal cellular machinery for virion production. Therefore, understanding the protein-protein interactions of EWS-FLI1 and the pathways that are regulated by these partnerships will inform both oncogenesis and therapeutics. This review describes the known protein partners and transcriptional targets of EWS-FLI1, while proposing strategies for exploiting these partnerships with targeted therapy.
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Affiliation(s)
- Hayriye V Erkizan
- Department of Oncology and Pediatrics, Lombardi Comprehensive Cancer Center, Georgetown University, Washington, DC, USA
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40
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Abstract
MK-STYX [MAPK (mitogen-activated protein kinase) phospho-serine/threonine/tyrosine-binding protein] is a pseudophosphatase member of the dual-specificity phosphatase subfamily of the PTPs (protein tyrosine phosphatases). MK-STYX is catalytically inactive due to the absence of two amino acids from the signature motif that are essential for phosphatase activity. The nucleophilic cysteine residue and the adjacent histidine residue, which are conserved in all active dual-specificity phosphatases, are replaced by serine and phenylalanine residues respectively in MK-STYX. Mutations to introduce histidine and cysteine residues into the active site of MK-STYX generated an active phosphatase. Using MS, we identified G3BP1 [Ras-GAP (GTPase-activating protein) SH3 (Src homology 3) domain-binding protein-1], a regulator of Ras signalling, as a binding partner of MK-STYX. We observed that G3BP1 bound to native MK-STYX; however, binding to the mutant catalytically active form of MK-STYX was dramatically reduced. G3BP1 is also an RNA-binding protein with endoribonuclease activity that is recruited to 'stress granules' after stress stimuli. Stress granules are large subcellular structures that serve as sites of mRNA sorting, in which untranslated mRNAs accumulate. We have shown that expression of MK-STYX inhibited stress granule formation induced either by aresenite or expression of G3BP itself; however, the catalytically active mutant MK-STYX was impaired in its ability to inhibit G3BP-induced stress granule assembly. These results reveal a novel facet of the function of a member of the PTP family, illustrating a role for MK-STYX in regulating the ability of G3BP1 to integrate changes in growth-factor stimulation and environmental stress with the regulation of protein synthesis.
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Abstract
Ewing's sarcoma family tumors are a good example of how genome research has advanced our understanding of the molecular pathogenesis of an otherwise enigmatic disease. This group of embryonal bone tumors is characterized by the expression of a chimeric ETS-family oncogene, predominantly EWS/FLI1. There is now convincing evidence for a mesenchymal descent from an early pluripotent progenitor. EWS/FLI1 has been shown to drive proliferation of Ewing's sarcoma cells and block most of the differentiation potential except for a partial neural gene expression program. The EWS/FLI1 fusion protein acts mainly as a gene activator, directly interacting with chromatin at two kinds of binding site: distant enhancers enriched in GGAA microsatellites, and proximal promoters containing classical ETS-binding motifs and recognition motifs for other transcription factors. EWS/FLI1 also represses a large number of genes, mainly indirectly, presumably by altering microRNA expression and epigenetic mechanisms, and potentially affecting post-transcriptional gene regulation. Modulation of EWS/FLI1 expression is not only a desirable therapeutic goal, but may also occur under physiological conditions and influence the course of the disease.
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42
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Vers une thérapeutique ciblée du sarcome d’Ewing par une stratégie antisens. ONCOLOGIE 2009. [DOI: 10.1007/s10269-009-1826-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Ordóñez JL, Osuna D, Herrero D, de Alava E, Madoz-Gúrpide J. Advances in Ewing's sarcoma research: where are we now and what lies ahead? Cancer Res 2009; 69:7140-50. [PMID: 19738075 DOI: 10.1158/0008-5472.can-08-4041] [Citation(s) in RCA: 95] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Ewing's sarcoma family tumors (EFT) are characterized by specific chromosomal translocations, which lead to EWS/ETS transcription factors. Elucidation of EWS/ETS target gene networks within the context of other signaling pathways, together with the identification of the initiating cell, and the development of genetically engineered mice will hopefully lead to biology-based therapeutic strategies for these tumors.
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Affiliation(s)
- José Luis Ordóñez
- Laboratory of Molecular Pathology of Sarcomas, Centro de Investigación del Cáncer-Instituto de Biología Molecular y Celular del Cáncer (IBMCC), Universidad de Salamanca-CSIC, Salamanca, Spain
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Herrero-Martín D, Osuna D, Ordóñez JL, Sevillano V, Martins AS, Mackintosh C, Campos M, Madoz-Gúrpide J, Otero-Motta AP, Caballero G, Amaral AT, Wai DH, Braun Y, Eisenacher M, Schaefer KL, Poremba C, de Alava E. Stable interference of EWS-FLI1 in an Ewing sarcoma cell line impairs IGF-1/IGF-1R signalling and reveals TOPK as a new target. Br J Cancer 2009; 101:80-90. [PMID: 19491900 PMCID: PMC2694277 DOI: 10.1038/sj.bjc.6605104] [Citation(s) in RCA: 88] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
BACKGROUND Ewing sarcoma is a paradigm of solid tumour -bearing chromosomal translocations resulting in fusion proteins that act as deregulated transcription factors. Ewing sarcoma translocations fuse the EWS gene with an ETS transcription factor, mainly FLI1. Most of the EWS-FLI1 target genes still remain unknown and many have been identified in heterologous model systems. METHODS We have developed a stable RNA interference model knocking down EWS-FLI1 in the Ewing sarcoma cell line TC71. Gene expression analyses were performed to study the effect of RNA interference on the genetic signature of EWS-FLI1 and to identify genes that could contribute to tumourigenesis. RESULTS EWS-FLI1 inhibition induced apoptosis, reduced cell migratory and tumourigenic capacities, and caused reduction in tumour growth. IGF-1 was downregulated and the IGF-1/IGF-1R signalling pathway was impaired. PBK/TOPK (T-LAK cell-originated protein kinase) expression was decreased because of EWS-FLI1 inhibition. We showed that TOPK is a new target gene of EWS-FLI1. TOPK inhibition prompted a decrease in the proliferation rate and a dramatic change in the cell's ability to grow in coalescence. CONCLUSION This is the first report of TOPK activity in Ewing sarcoma and suggests a significant role of this MAPKK-like protein kinase in the Ewing sarcoma biology.
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Affiliation(s)
- D Herrero-Martín
- Molecular Pathology Program, Centro de Investigación del Cáncer-IBMCC (USAL-CSIC), Campus Unamuno s/n, Salamanca, Spain.
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Embree LJ, Azuma M, Hickstein DD. Ewing sarcoma fusion protein EWSR1/FLI1 interacts with EWSR1 leading to mitotic defects in zebrafish embryos and human cell lines. Cancer Res 2009; 69:4363-71. [PMID: 19417137 DOI: 10.1158/0008-5472.can-08-3229] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The mechanism whereby the fusion of EWSR1 with the ETS transcription factor FLI1 contributes to malignant transformation in Ewing sarcoma remains unclear. We show that injection of human or zebrafish EWSR1/FLI1 mRNA into developing zebrafish embryos leads to mitotic defects with multipolar and disorganized mitotic spindles. Expression of human EWSR1/FLI1 in HeLa cells also results in mitotic defects, along with mislocalization of Aurora kinase B, a key regulator of mitotic progression. Because these mitotic abnormalities mimic those observed with the knockdown of EWSR1 in zebrafish embryos and HeLa cells, we investigated whether EWSR1/FLI1 interacts with EWSR1 and interferes with its function. EWSR1 coimmunoprecipitates with EWSR1/FLI1, and overexpression of EWSR1 rescues the mitotic defects in EWSR1/FLI1-transfected HeLa cells. This interaction between EWSR1/FLI1 and EWSR1 in Ewing sarcoma may induce mitotic defects leading to genomic instability and subsequent malignant transformation.
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Affiliation(s)
- Lisa J Embree
- Experimental Transplantation and Immunology Branch, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD 20892, USA
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Kauer M, Ban J, Kofler R, Walker B, Davis S, Meltzer P, Kovar H. A molecular function map of Ewing's sarcoma. PLoS One 2009; 4:e5415. [PMID: 19404404 PMCID: PMC2671847 DOI: 10.1371/journal.pone.0005415] [Citation(s) in RCA: 139] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2009] [Accepted: 03/27/2009] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND EWS-FLI1 is a chimeric ETS transcription factor that is, due to a chromosomal rearrangement, specifically expressed in Ewing's sarcoma family tumors (ESFT) and is thought to initiate the development of the disease. Previous genomic profiling experiments have identified EWS-FLI1-regulated genes and genes that discriminate ESFT from other sarcomas, but so far a comprehensive analysis of EWS-FLI1-dependent molecular functions characterizing this aggressive cancer is lacking. METHODOLOGY/PRINCIPAL FINDINGS In this study, a molecular function map of ESFT was constructed based on an integrative analysis of gene expression profiling experiments following EWS-FLI1 knockdown in a panel of five ESFT cell lines, and on gene expression data from the same platform of 59 primary ESFT. Out of 80 normal tissues tested, mesenchymal progenitor cells (MPC) were found to fit the hypothesis that EWS-FLI1 is the driving transcriptional force in ESFT best and were therefore used as the reference tissue for the construction of the molecular function map. The interrelations of molecular pathways were visualized by measuring the similarity among annotated gene functions by gene sharing. The molecular function map highlighted distinct clusters of activities for EWS-FLI1 regulated genes in ESFT and revealed a striking difference between EWS-FLI1 up- and down-regulated genes: EWS-FLI1 induced genes mainly belong to cell cycle regulation, proliferation, and response to DNA damage, while repressed genes were associated with differentiation and cell communication. CONCLUSIONS/SIGNIFICANCE This study revealed that EWS-FLI1 combines by distinct molecular mechanisms two important functions of cellular transformation in one protein, growth promotion and differentiation blockage. By taking MPC as a reference tissue, a significant EWS-FLI1 signature was discovered in ESFT that only partially overlapped with previously published EWS-FLI1-dependent gene expression patterns, identifying a series of novel targets for the chimeric protein in ESFT. Our results may guide target selection for future ESFT specific therapies.
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Affiliation(s)
- Maximilian Kauer
- Children's Cancer Research Institute, St. Anna Kinderkrebsforschung, Vienna, Austria
| | - Jozef Ban
- Children's Cancer Research Institute, St. Anna Kinderkrebsforschung, Vienna, Austria
| | - Reinhard Kofler
- Biocenter, Division of Molecular Pathophysiology, Medical University Innsbruck, Innsbruck, Austria
| | - Bob Walker
- Genetics Branch, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Sean Davis
- Genetics Branch, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Paul Meltzer
- Genetics Branch, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Heinrich Kovar
- Children's Cancer Research Institute, St. Anna Kinderkrebsforschung, Vienna, Austria
- * E-mail:
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Kikuta K, Tochigi N, Shimoda T, Yabe H, Morioka H, Toyama Y, Hosono A, Beppu Y, Kawai A, Hirohashi S, Kondo T. Nucleophosmin as a Candidate Prognostic Biomarker of Ewing's Sarcoma Revealed by Proteomics. Clin Cancer Res 2009; 15:2885-94. [DOI: 10.1158/1078-0432.ccr-08-1913] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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The oncogenic EWS-FLI1 protein binds in vivo GGAA microsatellite sequences with potential transcriptional activation function. PLoS One 2009; 4:e4932. [PMID: 19305498 PMCID: PMC2654724 DOI: 10.1371/journal.pone.0004932] [Citation(s) in RCA: 132] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2009] [Accepted: 02/21/2009] [Indexed: 12/21/2022] Open
Abstract
The fusion between EWS and ETS family members is a key oncogenic event in Ewing tumors and important EWS-FLI1 target genes have been identified. However, until now, the search for EWS-FLI1 targets has been limited to promoter regions and no genome-wide comprehensive analysis of in vivo EWS-FLI1 binding sites has been undertaken. Using a ChIP-Seq approach to investigate EWS-FLI1-bound DNA sequences in two Ewing cell lines, we show that this chimeric transcription factor preferentially binds two types of sequences including consensus ETS motifs and microsatellite sequences. Most bound sites are found outside promoter regions. Microsatellites containing more than 9 GGAA repeats are very significantly enriched in EWS-FLI1 immunoprecipitates. Moreover, in reporter gene experiments, the transcription activation is highly dependent upon the number of repeats that are included in the construct. Importantly, in vivo EWS-FLI1-bound microsatellites are significantly associated with EWS-FLI1-driven gene activation. Put together, these results point out the likely contribution of microsatellite elements to long-distance transcription regulation and to oncogenesis.
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Proctor A, Brownhill SC, Burchill SA. The promise of telomere length, telomerase activity and its regulation in the translocation-dependent cancer ESFT; clinical challenges and utility. Biochim Biophys Acta Mol Basis Dis 2009; 1792:260-74. [PMID: 19264125 DOI: 10.1016/j.bbadis.2009.02.011] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2009] [Revised: 02/19/2009] [Accepted: 02/20/2009] [Indexed: 01/12/2023]
Abstract
The Ewing's sarcoma family of tumours (ESFT) are diagnosed by EWS-ETS gene translocations. The resulting fusion proteins play a role in both the initiation and maintenance of these solid aggressive malignant tumours, suppressing cellular senescence and increasing cell proliferation and survival. EWS-ETS fusion proteins have altered transcriptional activity, inducing expression of a number of different target genes including telomerase. Up-regulation of hTERT is most likely responsible for the high levels of telomerase activity in primary ESFT, although telomerase activity and expression of hTERT are not predictive of outcome. However levels of telomerase activity in peripheral blood may be useful to monitor response to some therapeutics. Despite high levels of telomerase activity, telomeres in ESFT are frequently shorter than those of matched normal cells. Uncertainty about the role that telomerase and regulators of its activity play in the maintenance of telomere length in normal and cancer cells, and lack of studies examining the relationship between telomerase activity, regulators of its activity and their clinical significance in patient samples have limited their introduction into clinical practice. Studies in clinical samples using standardised assays are critical to establish how telomerase and regulators of its activity might best be exploited for patient benefit.
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Affiliation(s)
- Andrew Proctor
- Cancer Research UK Clinical Centre, Leeds Institute of Molecular Medicine, St James's University Hospital, Beckett Street, Leeds LS9 7TF, UK
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Abstract
Ewing's sarcoma is one of the few solid tumors for which the underlying molecular genetic abnormality has been described: rearrangement of the EWS gene on chromosome 22q12 with an ETS gene family member. These translocations define the Ewing's sarcoma family of tumors (ESFT) and provide a valuable tool for their accurate and unequivocal diagnosis. They also represent ideal targets for the development of tumor-specific therapeutics. Although secondary abnormalities occur in over 80% of primary ESFT the clinical utility of these is currently unclear. However, abnormalities in genes that regulate the G(1)/S checkpoint are frequently described and may be important in predicting outcome and response. Increased understanding of the molecular events that arise in ESFT and their role in the development and maintenance of the malignant phenotype will inform the improved stratification of patients for therapy and identify targets and pathways for the design of more effective cancer therapeutics.
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Affiliation(s)
- Susan Ann Burchill
- Candlelighter's Children's Cancer Research Group, Cancer Research UK Clinical Centre, Leeds Institute of Molecular Medicine, St James's University Hospital, Leeds, UK.
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