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1.
Proc Natl Acad Sci U S A ; 112(19): 6074-9, 2015 May 12.
Article in English | MEDLINE | ID: mdl-25918410

ABSTRACT

EWS (Ewing sarcoma) encodes an RNA/ssDNA binding protein that is frequently rearranged in a number of different cancers by chromosomal translocations. Physiologically, EWS has diverse and essential roles in various organ development and cellular processes. In this study, we uncovered a new role of EWS in mitochondrial homeostasis and energy metabolism. Loss of EWS leads to a significant decrease in mitochondria abundance and activity, which is caused by a rapid degradation of Peroxisome proliferator-activated receptor γ Coactivator (PGC-1α), a central regulator of mitochondria biogenesis, function, and cellular energy metabolism. EWS inactivation leads to increased ubiquitination and proteolysis of PGC-1α via proteasome pathway. Complementation of EWS in Ews-deficient cells restores PGC-1α and mitochondrial abundance. We found that expression of E3 ubiquitin ligase, FBXW7 (F-box/WD40 domain protein 7), is increased in the absence of Ews and depletion of Fbxw7 in Ews-null cells restores PGC-1α expression and mitochondrial density. Consistent with these findings, mitochondrial abundance and activity are significantly reduced in brown fat and skeletal muscles of Ews-deficient mice. Furthermore, expression of mitochondrial biogenesis, respiration and fatty acid ß-oxidation genes is significantly reduced in the liver of Ews-null mice. These results demonstrate a novel role of EWS in mitochondrial and cellular energy homeostasis by controlling PGC-1α protein stability, and further implicate altered mitochondrial and energy metabolism in cancers harboring the EWS translocation.


Subject(s)
Mitochondria/metabolism , RNA-Binding Protein EWS/antagonists & inhibitors , Transcription Factors/metabolism , Adipose Tissue, Brown/metabolism , Animals , DNA, Mitochondrial/metabolism , Energy Metabolism , F-Box Proteins/metabolism , F-Box-WD Repeat-Containing Protein 7 , Fatty Acids/chemistry , Fatty Acids/metabolism , Gene Expression Profiling , HEK293 Cells , Homeostasis , Humans , Liver/metabolism , Mice , Mice, Inbred C57BL , Mice, Knockout , Microscopy, Electron, Transmission , Muscle, Skeletal/metabolism , Oxygen/metabolism , Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha , Protein Conformation , RNA-Binding Protein EWS/metabolism , Ubiquitin/chemistry , Ubiquitin-Protein Ligases/metabolism
2.
EMBO Rep ; 13(2): 163-9, 2012 Feb 01.
Article in English | MEDLINE | ID: mdl-22173032

ABSTRACT

The Ras effector NORE1 is frequently silenced in primary adenocarcinomas, although the significance of this silencing for tumorigenesis is unclear. Here we show that NORE1 induces polyubiquitination and proteasomal degradation of oncoprotein HIPK1 by facilitating its interaction with the Mdm2 E3 ubiquitin ligase. Endogenous HIPK1 is stabilized in Nore1-deficient mouse embryonic fibroblasts, and depletion of HIPK1 in NORE1-silenced lung adenocarcinoma cells inhibits anchorage-independent cell growth and tumour formation in nude mice. These findings indicate that the control of HIPK1 stability by Mdm2-NORE1 has a major effect on cell behaviour, and epigenetic inactivation of NORE1 enables adenocarcinoma formation in vivo through HIPK1 stabilization.


Subject(s)
Adaptor Proteins, Signal Transducing/metabolism , Monomeric GTP-Binding Proteins/metabolism , Oncogene Proteins/metabolism , Protein Serine-Threonine Kinases/metabolism , Proteolysis , Proto-Oncogene Proteins c-mdm2/metabolism , ras Proteins/metabolism , Animals , Apoptosis Regulatory Proteins , Cell Line, Tumor , Cell Transformation, Neoplastic/metabolism , Cell Transformation, Neoplastic/pathology , Gene Knockdown Techniques , Humans , Mice , Polyubiquitin/metabolism , Protein Binding , Saccharomyces cerevisiae/metabolism , Ubiquitination
3.
Blood ; 117(4): 1156-66, 2011 Jan 27.
Article in English | MEDLINE | ID: mdl-21030557

ABSTRACT

The longevity of organisms is maintained by stem cells. If an organism loses the ability to maintain a balance between quiescence and differentiation in the stem/progenitor cell compartment due to aging and/or stress, this may result in death or age-associated diseases, including cancer. Ewing sarcoma is the most lethal bone tumor in young patients and arises from primitive stem cells. Here, we demonstrated that endogenous Ewing sarcoma gene (Ews) is indispensable for stem cell quiescence, and that the ablation of Ews promotes the early onset of senescence in hematopoietic stem progenitor cells. The phenotypic and functional changes in Ews-deficient stem cells were accompanied by an increase in senescence-associated ß-galactosidase staining and a marked induction of p16(INK4a) compared with wild-type counterparts. With its relevance to cancer and possibly aging, EWS is likely to play a significant role in maintaining the functional capacity of stem cells and may provide further insight into the complexity of Ewing sarcoma in the context of stem cells.


Subject(s)
Cellular Senescence/genetics , Hematopoietic Stem Cells/physiology , RNA-Binding Protein EWS/physiology , Animals , Cell Differentiation/genetics , Cells, Cultured , Embryo, Mammalian , Flow Cytometry , Hematopoiesis/genetics , Hematopoiesis/physiology , Hematopoietic Stem Cells/metabolism , Mice , Mice, Knockout , RNA-Binding Protein EWS/genetics , RNA-Binding Protein EWS/metabolism , Sarcoma, Ewing/genetics , Sarcoma, Ewing/metabolism
4.
J Biol Chem ; 286(22): 20087-99, 2011 Jun 03.
Article in English | MEDLINE | ID: mdl-21467033

ABSTRACT

Here, we demonstrate that troglitazone (Rezulin), a peroxisome proliferator-activated receptor agonist, acted in synergy with heregulin to induce massive cell death in breast cancer cells. Although the combination of heregulin and troglitazone (HRG/TGZ) induced both apoptosis and necrosis, the main mode of cell death was caspase-independent and occurred via necrosis. This combination increased generation of superoxide in mitochondria, which in turn destabilized mitochondria potential. Pretreatment with N-acetyl-l-cysteine and catalase expression ameliorated cell death induced by the combination treatment, indicating a role of oxidative stress in mediating HRG/TGZ-induced cell death. Notably, pretreatment with pyruvate significantly prevented the cell death, suggesting a potential mechanistic link between metabolic stress and HRG/TGZ-induced cell death. The activation of the HRG signaling axis has been considered as a poor prognostic factor in breast cancer and confers resistance to gefitinib (Iressa) and tamoxifen. However, our data presented here paradoxically suggest that HRG expression can actually be beneficial when it comes to treating breast cancer with peroxisome proliferator-activated receptor-γ ligands. Taken together, the combination of HRG and TGZ may provide a basis for the development of a novel strategy in the treatment of apoptosis-resistant and/or hormone-refractory breast cancer.


Subject(s)
Antineoplastic Agents/pharmacology , Apoptosis/drug effects , Breast Neoplasms/drug therapy , Chromans/pharmacology , Membrane Potential, Mitochondrial/drug effects , Neuregulin-1/pharmacology , PPAR gamma/agonists , Thiazolidinediones/pharmacology , Antineoplastic Agents/agonists , Breast Neoplasms/genetics , Breast Neoplasms/metabolism , Breast Neoplasms/pathology , Cell Line, Tumor , Chromans/agonists , Drug Synergism , Female , Humans , Necrosis , Neuregulin-1/agonists , Oxidative Stress/drug effects , PPAR gamma/genetics , PPAR gamma/metabolism , Signal Transduction/drug effects , Thiazolidinediones/agonists , Troglitazone
5.
Cancer Cell ; 2(6): 497-505, 2002 Dec.
Article in English | MEDLINE | ID: mdl-12498718

ABSTRACT

Desmoplastic small round cell tumor (DSRCT) is defined genetically by the chimeric fusion of the Ewing's sarcoma and Wilms' tumor genes, generating a novel transcription factor, EWS-WT1. By using cells with inducible EWS-WT1 to screen high-density microarrays, we identified BAIAP3 as a transcriptional target of the chimera. The BAIAP3 promoter is specifically bound in vivo by the (-KTS) isoform of EWS-WT1, consistent with its activation in reporter assays. BAIAP3 encodes a protein implicated in regulated exocytosis, which is colocalized with a secreted growth factor within cytoplasmic organelles. Ectopic expression of BAIAP3 in tumor cells dramatically enhances growth in low serum and colony formation in soft agar. BAIAP3 therefore encodes a transcriptional target of an oncogenic fusion protein that implicates the regulated exocytotic pathway in cancer cell proliferation.


Subject(s)
Carcinoma, Small Cell/genetics , Carcinoma, Small Cell/metabolism , Cell Transformation, Neoplastic , Exocytosis/physiology , Proteins/genetics , Proteins/metabolism , Angiogenesis Inhibitors , Animals , Base Sequence , Blotting, Northern , Cell Transformation, Neoplastic/genetics , Gene Expression Regulation, Neoplastic , Genes, Wilms Tumor , Humans , In Situ Hybridization , Molecular Sequence Data , Mosaicism , Oncogene Proteins, Fusion/genetics , Osteosarcoma/genetics , Osteosarcoma/metabolism , Promoter Regions, Genetic , RNA-Binding Protein EWS/genetics , Transcription, Genetic , Tumor Cells, Cultured/ultrastructure
6.
PLoS Genet ; 5(11): e1000745, 2009 Nov.
Article in English | MEDLINE | ID: mdl-19956686

ABSTRACT

Wilms' tumour (WT) is a pediatric tumor of the kidney that arises via failure of the fetal developmental program. The absence of identifiable mutations in the majority of WTs suggests the frequent involvement of epigenetic aberrations in WT. We therefore conducted a genome-wide analysis of promoter hypermethylation in WTs and identified hypermethylation at chromosome 5q31 spanning 800 kilobases (kb) and more than 50 genes. The methylated genes all belong to alpha-, beta-, and gamma-protocadherin (PCDH) gene clusters (Human Genome Organization nomenclature PCDHA@, PCDHB@, and PCDHG@, respectively). This demonstrates that long-range epigenetic silencing (LRES) occurs in developmental tumors as well as in adult tumors. Bisulfite polymerase chain reaction analysis showed that PCDH hypermethylation is a frequent event found in all Wilms' tumor subtypes. Hypermethylation is concordant with reduced PCDH expression in tumors. WT precursor lesions showed no PCDH hypermethylation, suggesting that de novo PCDH hypermethylation occurs during malignant progression. Discrete boundaries of the PCDH domain are delimited by abrupt changes in histone modifications; unmethylated genes flanking the LRES are associated with permissive marks which are absent from methylated genes within the domain. Silenced genes are marked with non-permissive histone 3 lysine 9 dimethylation. Expression analysis of embryonic murine kidney and differentiating rat metanephric mesenchymal cells demonstrates that Pcdh expression is developmentally regulated and that Pcdhg@ genes are expressed in blastemal cells. Importantly, we show that PCDHs negatively regulate canonical Wnt signalling, as short-interfering RNA-induced reduction of PCDHG@ encoded proteins leads to elevated beta-catenin protein, increased beta-catenin/T-cell factor (TCF) reporter activity, and induction of Wnt target genes. Conversely, over-expression of PCDHs suppresses beta-catenin/TCF-reporter activity and also inhibits colony formation and growth of cancer cells in soft agar. Thus PCDHs are candidate tumor suppressors that modulate regulatory pathways critical in development and disease, such as canonical Wnt signaling.


Subject(s)
Cadherins/genetics , Chromosomes, Human, Pair 5/genetics , Epigenesis, Genetic , Gene Silencing , Multigene Family , Wilms Tumor/genetics , Animals , DNA Methylation , Gene Expression Regulation , Genome-Wide Association Study , Humans , Mice , Promoter Regions, Genetic/genetics , Protocadherins , Rats , Signal Transduction/genetics , Wnt Proteins/genetics , Wnt Proteins/metabolism , beta Catenin/genetics
7.
Oncogenesis ; 11(1): 18, 2022 Apr 20.
Article in English | MEDLINE | ID: mdl-35443736

ABSTRACT

Desmoplastic Small Round Cell Tumor (DSRCT) is a rare and aggressive malignant cancer caused by a chromosomal translocation t(11;22)(p13;q12) that produces an oncogenic transcription factor, EWSR1-WT1. EWSR1-WT1 is essential for the initiation and progression of DSRCT. However, the precise mechanism by which EWSR1-WT1 drives DSRCT oncogenesis remains unresolved. Through our integrative gene expression analysis, we identified Salt Inducible Kinase 1 (SIK1) as a direct target of EWSR1-WT1. SIK1 as a member of the AMPK related kinase is involved in many biological processes. We showed that depletion of SIK1 causes inhibition of tumor cell growth, similar to the growth inhibition observed when EWSR1-WT1 is depleted. We further showed that silencing SIK1 leads to cessation of DNA replication in DSRCT cells and inhibition of tumor growth in vivo. Lastly, combined inhibition of SIK1 and CHEK1with small molecule inhibitors, YKL-05-099 and prexasertib, respectively, showed enhanced cytotoxicity in DSRCT cells compared to inhibition of either kinases alone. This work identified SIK1 as a new potential therapeutic target in DSRCT and the efficacy of SIK1 inhibition may be improved when combined with other intervention strategies.

8.
J Biol Chem ; 285(45): 35029-38, 2010 Nov 05.
Article in English | MEDLINE | ID: mdl-20810663

ABSTRACT

Epigenetic silencing of RASSF (Ras association domain family) genes RASSF1 and RASSF5 (also called NORE1) by CpG hypermethylation is found frequently in many cancers. Although the physiological roles of RASSF1 have been studied in some detail, the exact functions of RASSF5 are not well understood. Here, we show that RASSF5 plays an important role in mediating apoptosis in response to death receptor ligands, TNF-α and TNF-related apoptosis-inducing ligand. Depletion of RASSF5 by siRNA significantly reduced TNF-α-mediated apoptosis, likely through its interaction with proapoptotic kinase MST1, a mammalian homolog of Hippo. Consistent with this, siRNA knockdown of MST1 also resulted in resistance to TNF-α-induced apoptosis. To further study the role of Rassf5 in vivo, we generated Rassf5-deficient mouse. Inactivation of Rassf5 in mouse embryonic fibroblasts (MEFs) resulted in resistance to TNF-α- and TNF-related apoptosis-inducing ligand-mediated apoptosis. Importantly, Rassf5-null mice were significantly more resistant to TNF-α-induced apoptosis and failed to activate Mst1. Loss of Rassf5 also resulted in spontaneous immortalization of MEFs at earlier passages than the control MEFs, and Rassf5-null immortalized MEFs, but not the immortalized wild type MEFs, were fully transformed by K-RasG12V. Together, our results demonstrate a direct role for RASSF5 in death receptor ligand-mediated apoptosis and provide further evidence for RASSF5 as a tumor suppressor.


Subject(s)
Adaptor Proteins, Signal Transducing/metabolism , Apoptosis/physiology , Receptors, Death Domain/metabolism , Tumor Necrosis Factor-alpha/metabolism , Tumor Suppressor Proteins/metabolism , ras Proteins/metabolism , Adaptor Proteins, Signal Transducing/genetics , Animals , Apoptosis/drug effects , Apoptosis Regulatory Proteins , Cell Line , Embryo, Mammalian/cytology , Embryo, Mammalian/metabolism , Fibroblasts/cytology , Fibroblasts/metabolism , Gene Silencing/physiology , Mice , Mice, Knockout , Protein Serine-Threonine Kinases/genetics , Protein Serine-Threonine Kinases/metabolism , RNA, Small Interfering/genetics , Receptors, Death Domain/genetics , Tumor Necrosis Factor-alpha/pharmacology , Tumor Suppressor Proteins/genetics , ras Proteins/genetics
9.
J Biol Chem ; 285(19): 14585-93, 2010 May 07.
Article in English | MEDLINE | ID: mdl-20220130

ABSTRACT

Mammalian kidney development requires the functions of the Wilms tumor gene WT1 and the WNT/beta-catenin signaling pathway. Recent studies have shown that WT1 negatively regulates WNT/beta-catenin signaling, but the molecular mechanisms by which WT1 inhibits WNT/beta-catenin signaling are not completely understood. In this study, we identified a gene, CXXC5, which we have renamed WID (WT1-induced Inhibitor of Dishevelled), as a novel WT1 transcriptional target that negatively regulates WNT/beta-catenin signaling. WT1 activates WID transcription through the upstream enhancer region. In the developing kidney, Wid and Wt1 are coexpressed in podocytes of maturing nephrons. Structure-function analysis demonstrated that WID interacts with Dishevelled via its C-terminal CXXC zinc finger and Dishevelled binding domains and potently inhibits WNT/beta-catenin signaling in vitro and in vivo. WID is evolutionarily conserved, and ablation of wid in zebrafish embryos with antisense morpholino oligonucleotides perturbs embryonic kidney development. Taken together, our results demonstrate that the WT1 negatively regulates WNT/beta-catenin pathway via its target gene WID and further suggest a role for WID in nephrogenesis.


Subject(s)
Carrier Proteins/metabolism , Gene Expression Regulation, Neoplastic , Signal Transduction , WT1 Proteins/metabolism , Wnt Proteins/metabolism , beta Catenin/metabolism , Adaptor Proteins, Signal Transducing/genetics , Adaptor Proteins, Signal Transducing/metabolism , Animals , Axin Protein , Carrier Proteins/genetics , Chromatin Immunoprecipitation , DNA-Binding Proteins , Dishevelled Proteins , Down-Regulation , Embryo, Nonmammalian/cytology , Embryo, Nonmammalian/metabolism , Humans , Immunoblotting , Immunoglobulin G/immunology , Immunoprecipitation , Kidney/cytology , Kidney/metabolism , Luciferases/metabolism , Mice , NIH 3T3 Cells , Phosphoproteins/genetics , Phosphoproteins/metabolism , Promoter Regions, Genetic , RNA, Messenger/genetics , RNA, Messenger/metabolism , RNA, Small Interfering/pharmacology , Rabbits , Repressor Proteins/genetics , Repressor Proteins/metabolism , Reverse Transcriptase Polymerase Chain Reaction , Transcription Factors , WT1 Proteins/genetics , Wnt Proteins/genetics , Zebrafish , beta Catenin/genetics
10.
Clin Cancer Res ; 27(4): 1184-1194, 2021 02 15.
Article in English | MEDLINE | ID: mdl-33229458

ABSTRACT

PURPOSE: Desmoplastic small round cell tumor (DSRCT) is a highly lethal intra-abdominal sarcoma of adolescents and young adults. DSRCT harbors a t(11;22)(p13:q12) that generates the EWSR1-WT1 chimeric transcription factor, the key oncogenic driver of DSRCT. EWSR1-WT1 rewires global gene expression networks and activates aberrant expression of targets that together mediate oncogenesis. EWSR1-WT1 also activates a neural gene expression program. EXPERIMENTAL DESIGN: Among these neural markers, we found prominent expression of neurotrophic tyrosine kinase receptor 3 (NTRK3), a druggable receptor tyrosine kinase. We investigated the regulation of NTRK3 by EWSR1-WT1 and its potential as a therapeutic target in vitro and in vivo, the latter using novel patient-derived models of DSRCT. RESULTS: We found that EWSR1-WT1 binds upstream of NTRK3 and activates its transcription. NTRK3 mRNA is highly expressed in DSRCT compared with other major chimeric transcription factor-driven sarcomas and most DSRCTs are strongly immunoreactive for NTRK3 protein. Remarkably, expression of NTRK3 kinase domain mRNA in DSRCT is also higher than in cancers with NTRK3 fusions. Abrogation of NTRK3 expression by RNAi silencing reduces growth of DSRCT cells and pharmacologic targeting of NTRK3 with entrectinib is effective in both in vitro and in vivo models of DSRCT. CONCLUSIONS: Our results indicate that EWSR1-WT1 directly activates NTRK3 expression in DSRCT cells, which are dependent on its expression and activity for growth. Pharmacologic inhibition of NTRK3 by entrectinib significantly reduces growth of DSRCT cells both in vitro and in vivo, providing a rationale for clinical evaluation of NTRK3 as a therapeutic target in DSRCT.


Subject(s)
Benzamides/therapeutic use , Desmoplastic Small Round Cell Tumor/drug therapy , Indazoles/therapeutic use , Oncogene Proteins, Fusion/metabolism , RNA-Binding Protein EWS/antagonists & inhibitors , Adolescent , Adult , Animals , Benzamides/pharmacology , Cell Line, Tumor , Child , Desmoplastic Small Round Cell Tumor/genetics , Female , Gene Expression Regulation, Neoplastic , Humans , Indazoles/pharmacology , Male , Mice , Oncogene Proteins, Fusion/genetics , RNA-Binding Protein EWS/genetics , Receptor, trkC/genetics , Receptor, trkC/metabolism , WT1 Proteins/genetics , WT1 Proteins/metabolism , Xenograft Model Antitumor Assays , Young Adult
11.
Carcinogenesis ; 31(7): 1298-307, 2010 Jul.
Article in English | MEDLINE | ID: mdl-20400479

ABSTRACT

BACKGROUND AND AIMS: The underlying molecular mechanisms of hepatocellular carcinoma (HCC) remain poorly understood due to its complex development process. The human T cell-specific transcription factor sex-determining region Y-related high-mobility group (HMG) box 4 (SOX4) has been linked to development and tumorigenesis. In this study, we characterized the roles of SOX4 in regulation of the p53 transcription activity and evaluated the expression patterns and prognostic value of the transcription factor SOX4 in HCC. METHODS: The expression levels of human SOX4 were examined in HCC samples obtained from 58 patients having curative partial hepatectomy. The interaction and effects of SOX4 on the p53 pathway were assessed in HCC cell lines. Luciferase reporter assay to examine p53-mediated transcription of target genes was performed. The association of SOX4 expression level with tumor recurrence and overall survival was evaluated. RESULTS: We showed that the HMG box domain of SOX4 interacted with p53, resulting in the inhibition of p53-mediated transcription by the Bax promoter. More importantly, SOX4 overexpression led to a significant repression of p53-induced Bax expression and subsequent repression of p53-mediated apoptosis induced by gamma-irradiation. In clinicopathological analysis, nuclear overexpression of SOX4 was observed in 37 out of 58 (63.8%) HCC samples, and this correlated with diminished risk of recurrence (P = 0.014) and improved overall survival time (P = 0.045) in HCC patients. CONCLUSION: These results suggest that SOX4 contributes to hepatocarcinogenesis by inhibiting p53-mediated apoptosis and that its overexpression might be a useful prognostic marker for survival after surgical resection.


Subject(s)
Carcinoma, Hepatocellular/etiology , Liver Neoplasms/etiology , SOXC Transcription Factors/physiology , Tumor Suppressor Protein p53/physiology , Apoptosis , Carcinoma, Hepatocellular/pathology , Carcinoma, Hepatocellular/radiotherapy , Hep G2 Cells , Humans , Liver Neoplasms/pathology , Liver Neoplasms/radiotherapy , Promoter Regions, Genetic , Protein Structure, Tertiary , SOXC Transcription Factors/analysis , SOXC Transcription Factors/chemistry , Transcriptional Activation
12.
J Clin Invest ; 117(5): 1314-23, 2007 May.
Article in English | MEDLINE | ID: mdl-17415412

ABSTRACT

Ewing sarcoma gene EWS encodes a putative RNA-binding protein with proposed roles in transcription and splicing, but its physiological role in vivo remains undefined. Here, we have generated Ews-deficient mice and demonstrated that EWS is required for the completion of B cell development and meiosis. Analysis of Ews(-/-) lymphocytes revealed a cell-autonomous defect in precursor B lymphocyte (pre-B lymphocyte) development. During meiosis, Ews-null spermatocytes were deficient in XY bivalent formation and showed reduced meiotic recombination, resulting in massive apoptosis and complete arrest in gamete maturation. Inactivation of Ews in mouse embryonic fibroblasts resulted in premature cellular senescence, and the mutant animals showed hypersensitivity to ionizing radiation. Finally, we showed that EWS interacts with lamin A/C and that loss of EWS results in a reduced lamin A/C expression. Our findings reveal essential functions for EWS in pre-B cell development and meiosis, with proposed roles in DNA pairing and recombination/repair mechanisms. Furthermore, we demonstrate a novel role of EWS in cellular senescence, possibly through its interaction and modulation of lamin A/C.


Subject(s)
B-Lymphocyte Subsets/cytology , B-Lymphocyte Subsets/metabolism , Cell Differentiation/genetics , Meiosis/genetics , RNA-Binding Protein EWS/genetics , Sarcoma, Ewing/genetics , Animals , Animals, Newborn , Cell Differentiation/physiology , Cell Line, Tumor , Embryonic Stem Cells/physiology , Female , HeLa Cells , Humans , Male , Meiosis/physiology , Mice , Mice, Inbred C57BL , Mice, Knockout , RNA-Binding Protein EWS/deficiency , RNA-Binding Protein EWS/physiology , Retrospective Studies , Sarcoma, Ewing/metabolism , Sarcoma, Ewing/pathology
13.
Biochim Biophys Acta Mol Basis Dis ; 1865(7): 1938-1945, 2019 07 01.
Article in English | MEDLINE | ID: mdl-30481590

ABSTRACT

Ewing's sarcoma (EWS) is a bone cancer arising predominantly in young children. EWSR1 (Ewing Sarcoma breakpoint region 1/EWS RNA binding protein 1) gene is ubiquitously expressed in most cell types, indicating it has diverse roles in various cellular processes and organ development. Recently, several studies have shown that missense mutations of EWSR1 genes are known to be associated with central nervous system disorders such as amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). Otherwise, EWSR1 plays epigenetic roles in gene expression, RNA processing, and cellular signal transduction. Interestingly, EWSR1 controls micro RNA (miRNA) levels via Drosha, leading to autophagy dysfunction and impaired dermal development. Ewsr1 deficiency also leads to premature senescence of blood cells and gamete cells with a high rate of apoptosis due to the abnormal meiosis. Despite these roles of EWSR1 in various cellular functions, the exact mechanisms are not yet understood. In this context, the current review overviews a large body of evidence and discusses on what EWSR1 genetic mutations are associated with brain diseases and on how EWSR1 modulates cellular function via the epigenetic pathway. This will provide a better understanding of bona fide roles of EWSR1 in aging and its association with brain disorders.


Subject(s)
Aging , Brain Diseases/genetics , Epigenesis, Genetic , Mutation , RNA-Binding Protein EWS/genetics , Animals , Autophagy , Humans , MicroRNAs/genetics
14.
Cancer Res ; 66(9): 4561-5, 2006 May 01.
Article in English | MEDLINE | ID: mdl-16651405

ABSTRACT

BRCA1-associated RING domain protein BARD1, along with its heterodimeric partner BRCA1, plays important roles in cellular response to DNA damage. Immediate cellular response to genotoxic stress is mediated by a family of phosphoinositide 3-kinase-related protein kinases, such as ataxia-telangiectasia mutated (ATM), ATM and Rad3-related, and DNA-dependent protein kinase. ATM-mediated phosphorylation of BRCA1 enhances the DNA damage checkpoint functions of BRCA1, but how BARD1 is regulated during DNA damage signaling has not been examined. Here, we report that BARD1 undergoes phosphorylation upon ionizing radiation or UV radiation and identify Thr(714) as the in vivo BARD1 phosphorylation site. Importantly, DNA damage functions of BARD1 (i.e., inhibition of pre-mRNA polyadenylation and degradation of RNA polymerase II) are abrogated in T714A and T734A mutants. Our findings suggest that phosphorylation of BARD1 is critical for the DNA damage functions of the BRCA1/BARD1 complex.


Subject(s)
BRCA1 Protein/metabolism , DNA Damage/physiology , RNA, Messenger/antagonists & inhibitors , Tumor Suppressor Proteins/metabolism , Ubiquitin-Protein Ligases/metabolism , Amino Acid Sequence , BRCA1 Protein/antagonists & inhibitors , Bone Neoplasms/genetics , Bone Neoplasms/metabolism , Cell Line, Tumor , Conserved Sequence , Humans , Molecular Sequence Data , Osteosarcoma/genetics , Osteosarcoma/metabolism , Phosphatidylinositol 3-Kinases/metabolism , Phosphorylation , RNA, Messenger/genetics , RNA, Messenger/metabolism , Transfection , Tumor Suppressor Proteins/antagonists & inhibitors , Tumor Suppressor Proteins/genetics , Tumor Suppressor Proteins/radiation effects , Ubiquitin-Protein Ligases/antagonists & inhibitors , Ubiquitin-Protein Ligases/genetics , Ubiquitin-Protein Ligases/radiation effects
15.
Cancer Res ; 66(11): 5574-81, 2006 Jun 01.
Article in English | MEDLINE | ID: mdl-16740692

ABSTRACT

RNA helicase A (RHA), a member of the DEXH box helicase family of proteins, is an integral component of protein complexes that regulate transcription and splicing. The EWS-FLI1 oncoprotein is expressed as a result of the chromosomal translocation t(11;22) that occurs in patients with the Ewing's sarcoma family of tumors (ESFT). Using phage display library screening, we identified an EWS-FLI1 binding peptide containing homology to RHA. ESFT cell lines and patient tumors highly expressed RHA. GST pull-down and ELISA assays showed that EWS-FLI1 specifically bound RHA fragment amino acids 630 to 1020, which contains the peptide region discovered by phage display. Endogenous RHA was identified in a protein complex with EWS-FLI1 in ESFT cell lines. Chromatin immunoprecipitation experiments showed both EWS-FLI1 and RHA bound to EWS-FLI1 target gene promoters. RHA stimulated the transcriptional activity of EWS-FLI1 regulated promoters, including Id2, in ESFT cells. In addition, RHA expression in mouse embryonic fibroblast cells stably transfected with EWS-FLI1 enhanced the anchorage-independent phenotype above that with EWS-FLI1 alone. These results suggest that RHA interacts with EWS-FLI1 as a transcriptional cofactor to enhance its function.


Subject(s)
Autoantigens/metabolism , Oncogene Proteins, Fusion/metabolism , Proto-Oncogene Protein c-fli-1/metabolism , RNA Helicases/metabolism , Sarcoma, Ewing/metabolism , Animals , Autoantigens/biosynthesis , Autoantigens/genetics , Cell Adhesion/physiology , Cell Growth Processes/physiology , Cell Line, Tumor , DEAD-box RNA Helicases , Humans , Mice , Mice, Nude , Neoplasm Proteins , Oncogene Proteins, Fusion/genetics , Peptide Library , Peptides/metabolism , Promoter Regions, Genetic , Protein Binding , Proto-Oncogene Protein c-fli-1/genetics , RNA Helicases/biosynthesis , RNA Helicases/genetics , RNA-Binding Protein EWS , Recombinant Proteins/metabolism , Sarcoma, Ewing/enzymology , Sarcoma, Ewing/genetics , Transcriptional Activation , Transplantation, Heterologous
16.
Exp Neurobiol ; 27(2): 103-111, 2018 Apr.
Article in English | MEDLINE | ID: mdl-29731676

ABSTRACT

A recent study reveals that missense mutations of EWSR1 are associated with neurodegenerative disorders such as amyotrophic lateral sclerosis, but the function of wild-type (WT) EWSR1 in the central nervous system (CNS) is not known yet. Herein, we investigated the neuroanatomical and motor function changes in Ewsr1 knock out (KO) mice. First, we quantified neuronal nucleus size in the motor cortex, dorsal striatum and hippocampus of three different groups: WT, heterozygous Ewsr1 KO (+/-), and homozygous Ewsr1 KO (-/-) mice. The neuronal nucleus size was significantly smaller in the motor cortex and striatum of homozygous Ewsr1 KO (-/-) mice than that of WT. In addition, in the hippocampus, the neuronal nucleus size was significantly smaller in both heterozygous Ewsr1 KO (+/-) and homozygous Ewsr1 KO (-/-) mice. We then assessed motor function of Ewsr1 KO (-/-) and WT mice by a tail suspension test. Both forelimb and hindlimb movements were significantly increased in Ewsr1 KO (-/-) mice. Lastly, we performed immunohistochemistry to examine the expression of TH, DARPP-32, and phosphorylated (p)-DARPP-32 (Thr75) in the striatum and substantia nigra, which are associated with dopaminergic signaling. The immunoreactivity of TH and DARPP-32 was decreased in Ewsr1 KO (-/-) mice. Together, our results suggest that EWSR1 plays a significant role in neuronal morphology, dopaminergic signaling pathways, and motor function in the CNS of mice.

17.
BMC Med Genomics ; 9 Suppl 1: 33, 2016 08 12.
Article in English | MEDLINE | ID: mdl-27534535

ABSTRACT

BACKGROUND: Multifunctional transcription factor (TF) gene EWS/EWSR1 is involved in various cellular processes such as transcription regulation, noncoding RNA regulation, splicing regulation, genotoxic stress response, and cancer generation. Role of a TF gene can be effectively studied by measuring genome-wide gene expression, i.e., transcriptome, in an animal model of Ews/Ewsr1 knockout (KO). However, when a TF gene has complex multi-functions, conventional approaches such as differentially expressed genes (DEGs) analysis are not successful to characterize the role of the EWS gene. In this regard, network-based analyses that consider associations among genes are the most promising approach. METHODS: Networks are constructed and used to show associations among biological entities at various levels, thus different networks represent association at different levels. Taken together, in this paper, we report contributions on both computational and biological sides. RESULTS: Contribution on the computational side is to develop a novel computational framework that combines miRNA-gene network and protein-protein interaction network information to characterize the multifunctional role of EWS gene. On the biological side, we report that EWS regulates G-protein, Gnai1, in the spinal cord of Ews/Ewsr1 KO mice using the two biological network integrated analysis method. Neighbor proteins of Gnai1, G-protein complex subunits Gnb1, Gnb2 and Gnb4 were also down-regulated at their gene expression level. Interestingly, up-regulated genes, such as Rgs1 and Rgs19, are linked to the inhibition of Gnai1 activities. We further verified the altered expression of Gnai1 by qRT-PCR in Ews/Ewsr1 KO mice. CONCLUSIONS: Our integrated analysis of miRNA-transcriptome network and PPI network combined with qRT-PCR verifies that Gnai1 function is impaired in the spinal cord of Ews/Ewsr1 KO mice.


Subject(s)
Calmodulin-Binding Proteins/deficiency , Calmodulin-Binding Proteins/genetics , Computational Biology , GTP-Binding Protein alpha Subunits, Gi-Go/metabolism , MicroRNAs/genetics , Protein Interaction Mapping , RNA-Binding Proteins/genetics , Spinal Cord/metabolism , Animals , Gene Expression Profiling , Gene Ontology , Gene Regulatory Networks , Mice , Mice, Knockout , RNA, Messenger/genetics , RNA-Binding Protein EWS , Sequence Analysis, RNA
18.
Obesity (Silver Spring) ; 23(1): 138-44, 2015 Jan.
Article in English | MEDLINE | ID: mdl-25407167

ABSTRACT

OBJECTIVE: White adipose tissue is important for mammalian energy homeostasis and metabolism. It was previously demonstrated that Ewing sarcoma gene (EWS) is essential for early classical brown fat lineage determination, but its role in white adipocyte differentiation is not known. METHODS: Mouse embryonic fibroblasts (MEFs) lacking Ews and shRNA-mediated silencing of Ews in 3T3L1 preadipocytes were used to investigate the role of EWS in adipogenesis. White fat differentiation was determined by analyzing the expression of key adipogenic genes and by Oil red O staining. RESULTS: Following adipogenic stimulation, Ews expression arose rapidly in 3T3L1 cells during early induction period. Ews-null MEFs and 3T3L1 cells with reduced Ews expression failed to undergo adipogenesis. This was accompanied by significant reduction in the expression of critical early adipogenic regulators, Bmp2, Bmp4 (bone morphogenic protein 2 and 4), Cebpß, and Cebpδ (CCAAT/enhancer binding protein ß and δ). Complementation of recombinant BMP2 or BMP4 partially rescued adipogenesis in Ews-depleted 3T3L1 cells. CONCLUSIONS: These results demonstrate that EWS is essential during the early steps of white adipocyte differentiation, at least in part through its regulation of BMP2 and BMP4 expression.


Subject(s)
Adipogenesis/genetics , Adipose Tissue, White/physiology , RNA-Binding Protein EWS/physiology , 3T3-L1 Cells , Adipogenesis/drug effects , Adipose Tissue, White/drug effects , Animals , Bone Morphogenetic Protein 2/genetics , Bone Morphogenetic Protein 4/genetics , Cell Differentiation/drug effects , Cell Differentiation/genetics , Cells, Cultured , Embryonic Stem Cells/drug effects , Embryonic Stem Cells/physiology , Gene Expression Regulation/drug effects , Mice , RNA, Small Interfering/pharmacology , RNA-Binding Protein EWS/antagonists & inhibitors
19.
Article in English | MEDLINE | ID: mdl-26322018

ABSTRACT

Brown adipocytes are a specialized cell type that is critical for adaptive thermogenesis, energy homeostasis, and metabolism. In response to cold, both classical brown fat and the newly identified "beige" or "brite" cells are activated by ß-adrenergic signaling and catabolize stored lipids and carbohydrates to produce heat via UCP1. Once thought to be non-existent in adults, recent studies have discovered active classical brown and beige fat cells in humans, thus reinvigorating interest in brown and beige adipocytes. This review will focus on the newly discovered transcription factors and microRNAs that specify and orchestrate the classical brown and beige fat cell development.

20.
Autophagy ; 11(5): 796-811, 2015.
Article in English | MEDLINE | ID: mdl-25946189

ABSTRACT

The EWSR1 (EWS RNA-binding protein 1/Ewing Sarcoma Break Point Region 1) gene encodes a RNA/DNA binding protein that is ubiquitously expressed and involved in various cellular processes. EWSR1 deficiency leads to impairment of development and accelerated senescence but the mechanism is not known. Herein, we found that EWSR1 modulates the Uvrag (UV radiation resistance associated) gene at the post-transcription level. Interestingly, EWSR1 deficiency led to the activation of the DROSHA-mediated microprocessor complex and increased the level of Mir125a and Mir351, which directly target Uvrag. Moreover, the Mir125a- and Mir351-mediated reduction of Uvrag was associated with the inhibition of autophagy that was confirmed in ewsr1 knockout (KO) MEFs and ewsr1 KO mice. Taken together, our data indicate that EWSR1 is involved in the post-transcriptional regulation of Uvrag via a miRNA-dependent pathway, resulting in the deregulation of autophagy inhibition. The mechanism of Uvrag and autophagy regulation by EWSR1 provides new insights into the role of EWSR1 deficiency-related cellular dysfunction.


Subject(s)
Autophagy , Calmodulin-Binding Proteins/deficiency , MicroRNAs/metabolism , Tumor Suppressor Proteins/metabolism , Animals , Autophagy/genetics , Base Sequence , Calmodulin-Binding Proteins/metabolism , Down-Regulation/genetics , Embryo, Mammalian/cytology , Fibroblasts/metabolism , Mice , Mice, Knockout , Molecular Sequence Data , NIH 3T3 Cells , RNA-Binding Protein EWS , RNA-Binding Proteins , Transcription, Genetic
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