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Aguadé-Gorgorió J, Jami-Alahmadi Y, Calvanese V, Kardouh M, Fares I, Johnson H, Rezek V, Ma F, Magnusson M, Wang Y, Shin JE, Nance KJ, Goodridge HS, Liebscher S, Schenke-Layland K, Crooks GM, Wohlschlegel JA, Mikkola HKA. MYCT1 controls environmental sensing in human haematopoietic stem cells. Nature 2024; 630:412-420. [PMID: 38839950 PMCID: PMC11168926 DOI: 10.1038/s41586-024-07478-x] [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: 05/30/2023] [Accepted: 04/26/2024] [Indexed: 06/07/2024]
Abstract
The processes that govern human haematopoietic stem cell (HSC) self-renewal and engraftment are poorly understood and challenging to recapitulate in culture to reliably expand functional HSCs1-3. Here we identify MYC target 1 (MYCT1; also known as MTLC) as a crucial human HSC regulator that moderates endocytosis and environmental sensing in HSCs. MYCT1 is selectively expressed in undifferentiated human haematopoietic stem and progenitor cells (HSPCs) and endothelial cells but becomes markedly downregulated during HSC culture. Lentivirus-mediated knockdown of MYCT1 prevented human fetal liver and cord blood (CB) HSPC expansion and engraftment. By contrast, restoring MYCT1 expression improved the expansion and engraftment of cultured CB HSPCs. Single-cell RNA sequencing of human CB HSPCs in which MYCT1 was knocked down or overexpressed revealed that MYCT1 governs important regulatory programmes and cellular properties essential for HSC stemness, such as ETS factor expression and low mitochondrial activity. MYCT1 is localized in the endosomal membrane in HSPCs and interacts with vesicle trafficking regulators and signalling machinery. MYCT1 loss in HSPCs led to excessive endocytosis and hyperactive signalling responses, whereas restoring MYCT1 expression balanced culture-induced endocytosis and dysregulated signalling. Moreover, sorting cultured CB HSPCs on the basis of lowest endocytosis rate identified HSPCs with preserved MYCT1 expression and MYCT1-regulated HSC stemness programmes. Our work identifies MYCT1-moderated endocytosis and environmental sensing as essential regulatory mechanisms required to preserve human HSC stemness. Our data also pinpoint silencing of MYCT1 as a cell-culture-induced vulnerability that compromises human HSC expansion.
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Affiliation(s)
- Júlia Aguadé-Gorgorió
- Department of Molecular, Cell and Developmental Biology, University of California Los Angeles, Los Angeles, CA, USA.
- Eli and Edythe Broad Center for Regenerative Medicine and Stem Cell Research, University of California Los Angeles, Los Angeles, CA, USA.
| | - Yasaman Jami-Alahmadi
- Department of Biological Chemistry, University of California Los Angeles, Los Angeles, CA, USA
- Pfizer, Cambridge, MA, USA
| | - Vincenzo Calvanese
- Department of Molecular, Cell and Developmental Biology, University of California Los Angeles, Los Angeles, CA, USA
- Eli and Edythe Broad Center for Regenerative Medicine and Stem Cell Research, University of California Los Angeles, Los Angeles, CA, USA
- Laboratory for Molecular Cell Biology, University College London, London, UK
- Josep Carreras Leukaemia Research Institute, Barcelona, Spain
| | - Maya Kardouh
- Department of Molecular, Cell and Developmental Biology, University of California Los Angeles, Los Angeles, CA, USA
- Oakland University William Beaumont School of Medicine, Rochester, MI, USA
| | - Iman Fares
- Department of Molecular, Cell and Developmental Biology, University of California Los Angeles, Los Angeles, CA, USA
- Kite Pharma, Santa Monica, CA, USA
| | - Haley Johnson
- Department of Molecular, Cell and Developmental Biology, University of California Los Angeles, Los Angeles, CA, USA
- Department of Laboratory Medicine, University of California San Francisco, San Francisco, CA, USA
| | - Valerie Rezek
- Eli and Edythe Broad Center for Regenerative Medicine and Stem Cell Research, University of California Los Angeles, Los Angeles, CA, USA
- David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
- UCLA AIDS Institute, University of California Los Angeles, Los Angeles, CA, USA
| | - Feiyang Ma
- Department of Molecular, Cell and Developmental Biology, University of California Los Angeles, Los Angeles, CA, USA
- Institute for Genomics and Proteomics, University of California Los Angeles, Los Angeles, CA, USA
- Amgen, Thousand Oaks, CA, USA
| | - Mattias Magnusson
- Department of Molecular, Cell and Developmental Biology, University of California Los Angeles, Los Angeles, CA, USA
- Eli and Edythe Broad Center for Regenerative Medicine and Stem Cell Research, University of California Los Angeles, Los Angeles, CA, USA
- Division of Molecular Medicine and Gene Therapy, Lund Stem Cell Center, Lund University, Lund, Sweden
| | - Yanling Wang
- Department of Molecular, Cell and Developmental Biology, University of California Los Angeles, Los Angeles, CA, USA
| | - Juliana E Shin
- Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
- David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Karina J Nance
- Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Helen S Goodridge
- David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
- Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Simone Liebscher
- Institute of Biomedical Engineering, Department for Medical Technologies and Regenerative Medicine, Eberhard Karls University, Tübingen, Germany
| | - Katja Schenke-Layland
- Institute of Biomedical Engineering, Department for Medical Technologies and Regenerative Medicine, Eberhard Karls University, Tübingen, Germany
- NMI Natural and Medical Sciences Institute at the University Tübingen, Reutlingen, Germany
| | - Gay M Crooks
- Eli and Edythe Broad Center for Regenerative Medicine and Stem Cell Research, University of California Los Angeles, Los Angeles, CA, USA
- Jonsson Comprehensive Cancer Center, University of California Los Angeles, Los Angeles, CA, USA
- Department of Pathology and Laboratory Medicine, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, USA
| | - James A Wohlschlegel
- Department of Biological Chemistry, University of California Los Angeles, Los Angeles, CA, USA
| | - Hanna K A Mikkola
- Department of Molecular, Cell and Developmental Biology, University of California Los Angeles, Los Angeles, CA, USA.
- Eli and Edythe Broad Center for Regenerative Medicine and Stem Cell Research, University of California Los Angeles, Los Angeles, CA, USA.
- Jonsson Comprehensive Cancer Center, University of California Los Angeles, Los Angeles, CA, USA.
- Molecular Biology Institute, University of California Los Angeles, Los Angeles, CA, USA.
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2
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Xu J, Sun Y, Fu W, Fu S. MYCT1 in cancer development: Gene structure, regulation, and biological implications for diagnosis and treatment. Biomed Pharmacother 2023; 165:115208. [PMID: 37499454 DOI: 10.1016/j.biopha.2023.115208] [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] [Received: 05/12/2023] [Revised: 07/10/2023] [Accepted: 07/19/2023] [Indexed: 07/29/2023] Open
Abstract
Myc target 1 (MYCT1), located at 6q25.2, is a crucial player in cancer development. While widely distributed in cells, its subcellular localization varies across different cancer types. As a novel c-Myc target gene, MYCT1 is subject to regulation by multiple transcription factors. Studies have revealed aberrant expression of MYCT1 in various cancers, impacting pivotal biological processes such as proliferation, apoptosis, migration, genomic instability, and differentiation in cancer cells. Additionally, MYCT1 plays a critical role in modulating tumor angiogenesis and remodeling tumor immune responses within the tumor microenvironment. Despite certain debated functions, MYCT1 undeniably holds significance in cancer development. In this review, we comprehensively examine the relationship between MYCT1 and cancer, encompassing gene structure, regulation of gene expression, gene mutation, and biological function, with the aim of providing valuable insights for cancer diagnosis and treatment.
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Affiliation(s)
- Jianan Xu
- Department of Medical genetics, China Medical University, Shenyang 110022, PR China
| | - Yuanyuan Sun
- Department of Medical genetics, China Medical University, Shenyang 110022, PR China
| | - Weineng Fu
- Department of Medical genetics, China Medical University, Shenyang 110022, PR China
| | - Shuang Fu
- Department of Hematology Laboratory, Shengjing Hospital of China Medical University, Shenyang 110022, PR China; Department of Medical genetics, China Medical University, Shenyang 110022, PR China.
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3
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Clarkson TC, Iguchi N, Xie AX, Malykhina AP. Differential transcriptomic changes in the central nervous system and urinary bladders of mice infected with a coronavirus. PLoS One 2022; 17:e0278918. [PMID: 36490282 PMCID: PMC9733897 DOI: 10.1371/journal.pone.0278918] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Accepted: 11/28/2022] [Indexed: 12/13/2022] Open
Abstract
Multiple sclerosis (MS) often leads to the development of neurogenic lower urinary tract symptoms (LUTS). We previously characterized neurogenic bladder dysfunction in a mouse model of MS induced by a coronavirus, mouse hepatitis virus (MHV). The aim of the study was to identify genes and pathways linking neuroinflammation in the central nervous system with urinary bladder (UB) dysfunction to enhance our understanding of the mechanisms underlying LUTS in demyelinating diseases. Adult C57BL/6 male mice (N = 12) received either an intracranial injection of MHV (coronavirus-induced encephalomyelitis, CIE group), or sterile saline (control group). Spinal cord (SC) and urinary bladders (UB) were collected from CIE mice at 1 wk and 4 wks, followed by RNA isolation and NanoString nCounter Neuroinflammation assay. Transcriptome analysis of SC identified a significantly changed expression of >150 genes in CIE mice known to regulate astrocyte, microglia and oligodendrocyte functions, neuroinflammation and immune responses. Two genes were significantly upregulated (Ttr and Ms4a4a), and two were downregulated (Asb2 and Myct1) only in the UB of CIE mice. Siglec1 and Zbp1 were the only genes significantly upregulated in both tissues, suggesting a common transcriptomic link between neuroinflammation in the CNS and neurogenic changes in the UB of CIE mice.
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Affiliation(s)
- Taylor C. Clarkson
- Division of Urology, Department of Surgery, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States of America
| | - Nao Iguchi
- Division of Urology, Department of Surgery, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States of America
| | - Alison Xiaoqiao Xie
- Division of Urology, Department of Surgery, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States of America
| | - Anna P. Malykhina
- Division of Urology, Department of Surgery, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States of America
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Yu W, Liu W, Feng Y, Zhu C. Knockdown of GSG2 Suppresses the Progression of Colorectal Cancer Cells. Genet Test Mol Biomarkers 2022; 26:26-36. [PMID: 35089075 DOI: 10.1089/gtmb.2020.0298] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Introduction: As a serine/threonine kinase, Haspin (GSG2) has been reportedly associated with the development of malignant tumors. However, few studies have reported the role of GSG2 in colorectal cancer (CRC). Materials and Methods: Based on data from the Oncomine databases, GSG2 was found to be highly expressed in CRC patients' tissues. Therefore, the expression of GSG2 in CRC cell lines was subsequently evaluated. GSG2 loss-of-function experiments were conducted by infection with a lentivirus expressing shRNAs against GSG2. Colony-formation and cell viabilities were assessed using clonogenic and 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays, respectively. Migration was assessed using wound-healing and transwell assays. A GSG2 inhibitor experiment was used to investigate the key role of GSG2 in CRC. Immunoprecipitation was used to investigate the interaction between GSG2 and p-H3. In addition, apoptosis was evaluated by quantifying caspase 3/7 activities, and western blot analyses were used to investigate the underlying mechanisms of GSG2 in CRC. Results: GSG2 was found to be highly expressed in CRC tissues and cells. Furthermore, GSG2 knock-down suppressed proliferation, colony formation and invasion, and induced apoptosis in CRC cells. Mechanistically, GSG2 was revealed to regulate Myc, NF-κB, Snail-1, and β-catenin signaling. Conclusion: Collectively, we demonstrate that GSG2 is a potential biomarker of CRC, and that GSG2 interference suppresses the progression of CRC and promotes apoptosis in vitro. These data suggest GSG2 as a putative oncogene, but will require additional in vivo studies to confirm.
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Affiliation(s)
- Wenyan Yu
- Department of Oncology, The First Affiliated Hospital of Soochow University, Suzhou, China
| | - Wei Liu
- Department of Pathology, The First Affiliated Hospital of Soochow University, Suzhou, China
| | - Yuxin Feng
- Department of Oncology, The First Affiliated Hospital of Soochow University, Suzhou, China
| | - Chunrong Zhu
- Department of Oncology, The First Affiliated Hospital of Soochow University, Suzhou, China
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5
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Rodríguez-Zavala JS, Calleja LF, Moreno-Sánchez R, Yoval-Sánchez B. Role of Aldehyde Dehydrogenases in Physiopathological Processes. Chem Res Toxicol 2019; 32:405-420. [PMID: 30628442 DOI: 10.1021/acs.chemrestox.8b00256] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Many different diseases are associated with oxidative stress. One of the main consequences of oxidative stress at the cellular level is lipid peroxidation, from which toxic aldehydes may be generated. Below their toxicity thresholds, some aldehydes are involved in signaling processes, while others are intermediaries in the metabolism of lipids, amino acids, neurotransmitters, and carbohydrates. Some aldehydes ubiquitously distributed in the environment, such as acrolein or formaldehyde, are extremely toxic to the cell. On the other hand, aldehyde dehydrogenases (ALDHs) are able to detoxify a wide variety of aldehydes to their corresponding carboxylic acids, thus helping to protect from oxidative stress. ALDHs are located in different subcellular compartments such as cytosol, mitochondria, nucleus, and endoplasmic reticulum. The aim of this review is to analyze, and highlight, the role of different ALDH isoforms in the detoxification of aldehydes generated in processes that involve high levels of oxidative stress. The ALDH physiological relevance becomes evident by the observation that their expression and activity are enhanced in different pathologies that involve oxidative stress such as neurodegenerative disorders, cardiopathies, atherosclerosis, and cancer as well as inflammatory processes. Furthermore, ALDH mutations bring about several disorders in the cell. Thus, understanding the mechanisms by which these enzymes participate in diverse cellular processes may lead to better contend with the damage caused by toxic aldehydes in different pathologies by designing modulators and/or protocols to modify their activity or expression.
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Affiliation(s)
| | | | - Rafael Moreno-Sánchez
- Departamento de Bioquímica , Instituto Nacional de Cardiología , México 14080 , México
| | - Belem Yoval-Sánchez
- Departamento de Bioquímica , Instituto Nacional de Cardiología , México 14080 , México
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Wang H, Dolezal JM, Kulkarni S, Lu J, Mandel J, Jackson LE, Alencastro F, Duncan AW, Prochownik EV. Myc and ChREBP transcription factors cooperatively regulate normal and neoplastic hepatocyte proliferation in mice. J Biol Chem 2018; 293:14740-14757. [PMID: 30087120 DOI: 10.1074/jbc.ra118.004099] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2018] [Revised: 08/02/2018] [Indexed: 12/31/2022] Open
Abstract
Analogous to the c-Myc (Myc)/Max family of bHLH-ZIP transcription factors, there exists a parallel regulatory network of structurally and functionally related proteins with Myc-like functions. Two related Myc-like paralogs, termed MondoA and MondoB/carbohydrate response element-binding protein (ChREBP), up-regulate gene expression in heterodimeric association with the bHLH-ZIP Max-like factor Mlx. Myc is necessary to support liver cancer growth, but not for normal hepatocyte proliferation. Here, we investigated ChREBP's role in these processes and its relationship to Myc. Unlike Myc loss, ChREBP loss conferred a proliferative disadvantage to normal murine hepatocytes, as did the combined loss of ChREBP and Myc. Moreover, hepatoblastomas (HBs) originating in myc-/-, chrebp-/-, or myc-/-/chrebp-/- backgrounds grew significantly more slowly. Metabolic studies on livers and HBs in all three genetic backgrounds revealed marked differences in oxidative phosphorylation, fatty acid β-oxidation (FAO), and pyruvate dehydrogenase activity. RNA-Seq of livers and HBs suggested seven distinct mechanisms of Myc-ChREBP target gene regulation. Gene ontology analysis indicated that many transcripts deregulated in the chrebp-/- background encode enzymes functioning in glycolysis, the TCA cycle, and β- and ω-FAO, whereas those dysregulated in the myc-/- background encode enzymes functioning in glycolysis, glutaminolysis, and sterol biosynthesis. In the myc-/-/chrebp-/- background, additional deregulated transcripts included those involved in peroxisomal β- and α-FAO. Finally, we observed that Myc and ChREBP cooperatively up-regulated virtually all ribosomal protein genes. Our findings define the individual and cooperative proliferative, metabolic, and transcriptional roles for the "Extended Myc Network" under both normal and neoplastic conditions.
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Affiliation(s)
- Huabo Wang
- From the Division of Hematology/Oncology, Children's Hospital of Pittsburgh of UPMC
| | - James M Dolezal
- From the Division of Hematology/Oncology, Children's Hospital of Pittsburgh of UPMC
| | - Sucheta Kulkarni
- From the Division of Hematology/Oncology, Children's Hospital of Pittsburgh of UPMC
| | - Jie Lu
- From the Division of Hematology/Oncology, Children's Hospital of Pittsburgh of UPMC
| | - Jordan Mandel
- From the Division of Hematology/Oncology, Children's Hospital of Pittsburgh of UPMC
| | - Laura E Jackson
- From the Division of Hematology/Oncology, Children's Hospital of Pittsburgh of UPMC
| | | | | | - Edward V Prochownik
- From the Division of Hematology/Oncology, Children's Hospital of Pittsburgh of UPMC, .,the Pittsburgh Liver Center.,the Hillman Cancer Center of UPMC, and.,the Department of Microbiology and Molecular Genetics, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania 15224
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7
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Qu S, Sun Y, Li Y, Xu Z, Fu W. YY1 directly suppresses MYCT1 leading to laryngeal tumorigenesis and progress. Cancer Med 2017; 6:1389-1398. [PMID: 28485541 PMCID: PMC5463081 DOI: 10.1002/cam4.1073] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2017] [Revised: 02/07/2017] [Accepted: 03/15/2017] [Indexed: 12/14/2022] Open
Abstract
YY1 is a key transcription factor and plays different roles in various cancers. However, role and mechanism of YY1 in laryngeal cancer are still unknown. YY1 and MYCT1 mRNA and protein levels were detected by Real-time RT-PCR and Western Blot methods, respectively. Binding of YY1 to MYCT1 promoter was predicted and confirmed by bioinformatics and chromatin immunoprecipitation assays, respectively. MYCT1 promoter activity was assessed by dual luciferase assay system. Laryngeal cancer cell proliferation, migration, and apoptosis were evaluated by cell viability, colony formation, cell scratch assay, transwell assay, and flow cytometry methods, respectively. YY1 and MYCT1 were upregulated and downregulated at transcriptional level in laryngeal cancer, respectively, which showed a negative correlation between YY1 and MYCT1 expression in laryngeal cancer. Significantly higher expression of YY1 and lower expression of MYCT1 were found in laryngeal cancer tissues of patients with lymphatic metastasis than those without metastasis.YY1 directly bound to MYCT1 promoter region and inhibited its promoter activity. YY1 silence had similar biological functions as MYCT1 overexpression in repressiveness of proliferation and migration, and promotion of apoptosis in laryngeal cancer cells. However, the effects of YY1 silence were recovered by MYCT1 knockdown. YY1 promotes proliferation and migration with suppression of apoptosis via directly inhibiting MYCT1 in laryngeal cancer cells, suggesting that YY1 is a useful target as a potential oncogene in laryngeal cancer development and progression.
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Affiliation(s)
- Si‐Yao Qu
- Department of Medical GeneticsChina Medical UniversityShenyang110122China
- National Laboratory of Medical Molecular BiologyInstitute of Basic Medical SciencesChinese Academy of Medical Sciences & Peking Union Medical CollegeBeijing100005China
| | - Yuan‐Yuan Sun
- Department of Medical GeneticsChina Medical UniversityShenyang110122China
| | - Yun‐Hui Li
- Department of Laboratory MedicineNo. 202 Hospital of PLAShenyang110003China
| | - Zhen‐Ming Xu
- Department of OtolaryngologyNo. 463 Hospital of PLAShenyang110007China
| | - Wei‐Neng Fu
- Department of Medical GeneticsChina Medical UniversityShenyang110122China
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Hartl M. The Quest for Targets Executing MYC-Dependent Cell Transformation. Front Oncol 2016; 6:132. [PMID: 27313991 PMCID: PMC4889588 DOI: 10.3389/fonc.2016.00132] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2016] [Accepted: 05/20/2016] [Indexed: 12/26/2022] Open
Abstract
MYC represents a transcription factor with oncogenic potential converting multiple cellular signals into a broad transcriptional response, thereby controlling the expression of numerous protein-coding and non-coding RNAs important for cell proliferation, metabolism, differentiation, and apoptosis. Constitutive activation of MYC leads to neoplastic cell transformation, and deregulated MYC alleles are frequently observed in many human cancer cell types. Multiple approaches have been performed to isolate genes differentially expressed in cells containing aberrantly activated MYC proteins leading to the identification of thousands of putative targets. Functional analyses of genes differentially expressed in MYC-transformed cells had revealed that so far more than 40 upregulated or downregulated MYC targets are actively involved in cell transformation or tumorigenesis. However, further systematic and selective approaches are required for determination of the known or yet unidentified targets responsible for processing the oncogenic MYC program. The search for critical targets in MYC-dependent tumor cells is exacerbated by the fact that during tumor development, cancer cells progressively evolve in a multistep process, thereby acquiring their characteristic features in an additive manner. Functional expression cloning, combinatorial gene expression, and appropriate in vivo tests could represent adequate tools for dissecting the complex scenario of MYC-specified cell transformation. In this context, the central goal is to identify a minimal set of targets that suffices to phenocopy oncogenic MYC. Recently developed genomic editing tools could be employed to confirm the requirement of crucial transformation-associated targets. Knowledge about essential MYC-regulated genes is beneficial to expedite the development of specific inhibitors to interfere with growth and viability of human tumor cells in which MYC is aberrantly activated. Approaches based on the principle of synthetic lethality using MYC-overexpressing cancer cells and chemical or RNAi libraries have been employed to search for novel anticancer drugs, also leading to the identification of several druggable targets. Targeting oncogenic MYC effector genes instead of MYC may lead to compounds with higher specificities and less side effects. This class of drugs could also display a wider pharmaceutical window because physiological functions of MYC, which are important for normal cell growth, proliferation, and differentiation would be less impaired.
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Affiliation(s)
- Markus Hartl
- Institute of Biochemistry and Center of Molecular Biosciences (CMBI), University of Innsbruck , Innsbruck , Austria
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Wu S, Gui J, Yin X, Pan Q, Liu X, Chu L. Transmembrane domain is crucial to the subcellular localization and function of Myc target 1. J Cell Mol Med 2015; 20:471-81. [PMID: 26710964 PMCID: PMC4759468 DOI: 10.1111/jcmm.12747] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Accepted: 10/30/2015] [Indexed: 12/20/2022] Open
Abstract
Deregulation of c-MYC occurs in a variety of human cancers. Overexpression of c-MYC promotes cell growth, proliferation, apoptosis, transformation and genomic instability. MYC target 1 (MYCT1) is a direct target gene of c-MYC, and its murine homologue MT-MC1 recapitulated multiple c-Myc-related phenotypes. However, the molecular mechanism of MYCT1 remains unclear. Here, we identified the transmembrane (TM) domain of MYCT1, not the nuclear localization sequence, is indispensable to the vesicle-associated localization of MYCT1 protein in the cytoplasmic membrane vesicle. Overexpression of MYCT1, not MYCT1 (ΔTM), decreased cell viability under serum deprivation and increased tumour cell migration ability. We further identified CKAP4 interacted with MYCT1 and contributed to the function of MYCT1. In addition, we found that a mutation, A88D, which is observed in patient sample, changed the localization, and abolished the effect on cell viability and cell migration, suggesting that the TM domain is critical to MYCT1.
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Affiliation(s)
- Shuai Wu
- State Key Laboratory of Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Jinghua Gui
- State Key Laboratory of Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Xiaofei Yin
- State Key Laboratory of Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Qiang Pan
- State Key Laboratory of Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Xinyuan Liu
- State Key Laboratory of Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Liang Chu
- State Key Laboratory of Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
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10
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Notas G, Pelekanou V, Kampa M, Alexakis K, Sfakianakis S, Laliotis A, Askoxilakis J, Tsentelierou E, Tzardi M, Tsapis A, Castanas E. Tamoxifen induces a pluripotency signature in breast cancer cells and human tumors. Mol Oncol 2015; 9:1744-59. [PMID: 26115764 DOI: 10.1016/j.molonc.2015.05.008] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2015] [Accepted: 05/20/2015] [Indexed: 01/01/2023] Open
Abstract
Tamoxifen is the treatment of choice in estrogen receptor alpha breast cancer patients that are eligible for adjuvant endocrine therapy. However, ∼50% of ERα-positive tumors exhibit intrinsic or rapidly acquire resistance to endocrine treatment. Unfortunately, prediction of de novo resistance to endocrine therapy and/or assessment of relapse likelihood remain difficult. While several mechanisms regulating the acquisition and the maintenance of endocrine resistance have been reported, there are several aspects of this phenomenon that need to be further elucidated. Altered metabolic fate of tamoxifen within patients and emergence of tamoxifen-resistant clones, driven by evolution of the disease phenotype during treatment, appear as the most compelling hypotheses so far. In addition, tamoxifen was reported to induce pluripotency in breast cancer cell lines, in vitro. In this context, we have performed a whole transcriptome analysis of an ERα-positive (T47D) and a triple-negative breast cancer cell line (MDA-MB-231), exposed to tamoxifen for a short time frame (hours), in order to identify how early pluripotency-related effects of tamoxifen may occur. Our ultimate goal was to identify whether the transcriptional actions of tamoxifen related to induction of pluripotency are mediated through specific ER-dependent or independent mechanisms. We report that even as early as 3 hours after the exposure of breast cancer cells to tamoxifen, a subset of ERα-dependent genes associated with developmental processes and pluripotency are induced and this is accompanied by specific phenotypic changes (expression of pluripotency-related proteins). Furthermore we report an association between the increased expression of pluripotency-related genes in ERα-positive breast cancer tissues samples and disease relapse after tamoxifen therapy. Finally we describe that in a small group of ERα-positive breast cancer patients, with disease relapse after surgery and tamoxifen treatment, ALDH1A1 (a marker of pluripotency in epithelial cancers which is absent in normal breast tissue) is increased in relapsing tumors, with a concurrent modification of its intra-cellular localization. Our data could be of value in the discrimination of patients susceptible to develop tamoxifen resistance and in the selection of optimized patient-tailored therapies.
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Affiliation(s)
- George Notas
- Laboratories of Experimental Endocrinology, University of Crete School of Medicine, Heraklion, Greece; Institute of Applied Computational Mathematics, Foundation of Research and Technology (FORTH), Heraklion, Greece.
| | - Vassiliki Pelekanou
- Laboratories of Experimental Endocrinology, University of Crete School of Medicine, Heraklion, Greece; Laboratories of Pathology, University of Crete School of Medicine, Heraklion, Greece
| | - Marilena Kampa
- Laboratories of Experimental Endocrinology, University of Crete School of Medicine, Heraklion, Greece
| | - Konstantinos Alexakis
- Laboratories of Experimental Endocrinology, University of Crete School of Medicine, Heraklion, Greece
| | - Stelios Sfakianakis
- Institute of Computer Science, Foundation of Research and Technology (FORTH), Heraklion, Greece
| | - Aggelos Laliotis
- Department of Surgical Oncology, University Hospital, Heraklion, Greece
| | - John Askoxilakis
- Department of Surgical Oncology, University Hospital, Heraklion, Greece
| | | | - Maria Tzardi
- Laboratories of Pathology, University of Crete School of Medicine, Heraklion, Greece
| | - Andreas Tsapis
- Laboratories of Experimental Endocrinology, University of Crete School of Medicine, Heraklion, Greece; INSERM U976, Hôpital Saint Louis, Paris, France; University Paris Diderot, Paris, France
| | - Elias Castanas
- Laboratories of Experimental Endocrinology, University of Crete School of Medicine, Heraklion, Greece.
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Dun MD, Chalkley RJ, Faulkner S, Keene S, Avery-Kiejda KA, Scott RJ, Falkenby LG, Cairns MJ, Larsen MR, Bradshaw RA, Hondermarck H. Proteotranscriptomic Profiling of 231-BR Breast Cancer Cells: Identification of Potential Biomarkers and Therapeutic Targets for Brain Metastasis. Mol Cell Proteomics 2015; 14:2316-30. [PMID: 26041846 DOI: 10.1074/mcp.m114.046110] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2014] [Indexed: 11/06/2022] Open
Abstract
Brain metastases are a devastating consequence of cancer and currently there are no specific biomarkers or therapeutic targets for risk prediction, diagnosis, and treatment. Here the proteome of the brain metastatic breast cancer cell line 231-BR has been compared with that of the parental cell line MDA-MB-231, which is also metastatic but has no organ selectivity. Using SILAC and nanoLC-MS/MS, 1957 proteins were identified in reciprocal labeling experiments and 1584 were quantified in the two cell lines. A total of 152 proteins were confidently determined to be up- or down-regulated by more than twofold in 231-BR. Of note, 112/152 proteins were decreased as compared with only 40/152 that were increased, suggesting that down-regulation of specific proteins is an important part of the mechanism underlying the ability of breast cancer cells to metastasize to the brain. When matched against transcriptomic data, 43% of individual protein changes were associated with corresponding changes in mRNA, indicating that the transcript level is a limited predictor of protein level. In addition, differential miRNA analyses showed that most miRNA changes in 231-BR were up- (36/45) as compared with down-regulations (9/45). Pathway analysis revealed that proteome changes were mostly related to cell signaling and cell cycle, metabolism and extracellular matrix remodeling. The major protein changes in 231-BR were confirmed by parallel reaction monitoring mass spectrometry and consisted in increases (by more than fivefold) in the matrix metalloproteinase-1, ephrin-B1, stomatin, myc target-1, and decreases (by more than 10-fold) in transglutaminase-2, the S100 calcium-binding protein A4, and l-plastin. The clinicopathological significance of these major proteomic changes to predict the occurrence of brain metastases, and their potential value as therapeutic targets, warrants further investigation.
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Affiliation(s)
- Matthew D Dun
- From the ‡School of Biomedical Sciences & Pharmacy and §Hunter Medical Research Institute, Faculty of Health and Medicine, University of Newcastle, Callaghan, New South Wales 2308, Australia
| | - Robert J Chalkley
- ¶Department of Pharmaceutical Chemistry, University of California San Francisco, California 94158
| | - Sam Faulkner
- From the ‡School of Biomedical Sciences & Pharmacy and §Hunter Medical Research Institute, Faculty of Health and Medicine, University of Newcastle, Callaghan, New South Wales 2308, Australia
| | - Sheridan Keene
- From the ‡School of Biomedical Sciences & Pharmacy and §Hunter Medical Research Institute, Faculty of Health and Medicine, University of Newcastle, Callaghan, New South Wales 2308, Australia
| | - Kelly A Avery-Kiejda
- From the ‡School of Biomedical Sciences & Pharmacy and §Hunter Medical Research Institute, Faculty of Health and Medicine, University of Newcastle, Callaghan, New South Wales 2308, Australia
| | - Rodney J Scott
- From the ‡School of Biomedical Sciences & Pharmacy and §Hunter Medical Research Institute, Faculty of Health and Medicine, University of Newcastle, Callaghan, New South Wales 2308, Australia
| | - Lasse G Falkenby
- ‖Department of Biochemistry and Molecular Biology, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark
| | - Murray J Cairns
- From the ‡School of Biomedical Sciences & Pharmacy and §Hunter Medical Research Institute, Faculty of Health and Medicine, University of Newcastle, Callaghan, New South Wales 2308, Australia
| | - Martin R Larsen
- ‖Department of Biochemistry and Molecular Biology, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark
| | - Ralph A Bradshaw
- ¶Department of Pharmaceutical Chemistry, University of California San Francisco, California 94158
| | - Hubert Hondermarck
- From the ‡School of Biomedical Sciences & Pharmacy and §Hunter Medical Research Institute, Faculty of Health and Medicine, University of Newcastle, Callaghan, New South Wales 2308, Australia
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12
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Teitz T, Inoue M, Valentine MB, Zhu K, Rehg JE, Zhao W, Finkelstein D, Wang YD, Johnson MD, Calabrese C, Rubinstein M, Hakem R, Weiss WA, Lahti JM. Th-MYCN mice with caspase-8 deficiency develop advanced neuroblastoma with bone marrow metastasis. Cancer Res 2013; 73:4086-97. [PMID: 23536557 PMCID: PMC3702642 DOI: 10.1158/0008-5472.can-12-2681] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Neuroblastoma, the most common extracranial pediatric solid tumor, is responsible for 15% of all childhood cancer deaths. Patients frequently present at diagnosis with metastatic disease, particularly to the bone marrow. Advances in therapy and understanding of the metastatic process have been limited due, in part, to the lack of animal models harboring bone marrow disease. The widely used transgenic model, the Th-MYCN mouse, exhibits limited metastasis to this site. Here, we establish the first genetic immunocompetent mouse model for metastatic neuroblastoma with enhanced secondary tumors in the bone marrow. This model recapitulates 2 frequent alterations in metastatic neuroblastoma, overexpression of MYCN and loss of caspase-8 expression. Mouse caspase-8 gene was deleted in neural crest lineage cells by crossing a Th-Cre transgenic mouse with a caspase-8 conditional knockout mouse. This mouse was then crossed with the neuroblastoma prone Th-MYCN mouse. Although overexpression of MYCN by itself rarely caused bone marrow metastasis, combining MYCN overexpression and caspase-8 deletion significantly enhanced bone marrow metastasis (37% incidence). Microarray expression studies of the primary tumors mRNAs and microRNAs revealed extracellular matrix structural changes, increased expression of genes involved in epithelial to mesenchymal transition, inflammation, and downregulation of miR-7a and miR-29b. These molecular changes have been shown to be associated with tumor progression and activation of the cytokine TGF-β pathway in various tumor models. Cytokine TGF-β can preferentially promote single cell motility and blood-borne metastasis and therefore activation of this pathway may explain the enhanced bone marrow metastasis observed in this animal model.
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Affiliation(s)
- Tal Teitz
- Department of Tumor Cell Biology, St. Jude Children’s Research Hospital,
Memphis, TN 38105, USA
| | - Madoka Inoue
- Department of Tumor Cell Biology, St. Jude Children’s Research Hospital,
Memphis, TN 38105, USA
| | - Marcus B. Valentine
- Department of Tumor Cell Biology, St. Jude Children’s Research Hospital,
Memphis, TN 38105, USA
| | - Kejin Zhu
- Department of Tumor Cell Biology, St. Jude Children’s Research Hospital,
Memphis, TN 38105, USA
| | - Jerold E. Rehg
- Department of Pathology, St. Jude Children’s Research Hospital, Memphis, TN
38105, USA
| | - Wei Zhao
- Department of Biostatistics, St. Jude Children’s Research Hospital, Memphis,
TN 38105, USA
| | - David Finkelstein
- Department of Computational Biology, St. Jude Children’s Research Hospital,
Memphis, TN 38105, USA
| | - Yong-Dong Wang
- Hartwell Center for Bioinformatics and Biotechnology, St. Jude Children’s
Research Hospital, Memphis, TN 38105, USA
| | - Melissa D. Johnson
- Animal Imaging Center, St. Jude Children’s Research Hospital, Memphis, TN
38105, USA
| | - Christopher Calabrese
- Animal Imaging Center, St. Jude Children’s Research Hospital, Memphis, TN
38105, USA
| | - Marcelo Rubinstein
- Instituto de Investigaciones en Ingeniería Genética y Biología
Molecular, Consejo Nacional de Investigaciones Científicas y Tecnológicas and
Universidad de Buenos Aires C1428ADN, Argentina
| | - Razqallah Hakem
- Department of Medical Biophysics, Ontario Cancer Institute, University of Toronto,
Toronto, Ontario M5G 2M9, Canada
| | - William A. Weiss
- Departments of Neurology, Pediatrics and Neurological Surgery, University of
California, San Francisco, CA 94158, USA
| | - Jill M. Lahti
- Department of Tumor Cell Biology, St. Jude Children’s Research Hospital,
Memphis, TN 38105, USA
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13
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Yang M, Li W, Liu YY, Fu S, Qiu GB, Sun KL, Fu WN. Promoter hypermethylation-induced transcriptional down-regulation of the gene MYCT1 in laryngeal squamous cell carcinoma. BMC Cancer 2012; 12:219. [PMID: 22672838 PMCID: PMC3472177 DOI: 10.1186/1471-2407-12-219] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2012] [Accepted: 06/06/2012] [Indexed: 12/21/2022] Open
Abstract
Background MYCT1, previously named MTLC, is a novel candidate tumor suppressor gene. MYCT1 was cloned from laryngeal squamous cell cancer (LSCC) and has been found to be down-regulated in LSCC; however, the regulatory details have not been fully elucidated. Methods Here, we sought to investigate the methylation status of the CpG islands of MYCT1 and mRNA levels by bisulfite-specific PCR (BSP) based on sequencing restriction enzyme digestion, reverse transcription and real-time quantitative polymerase chain reaction (RQ-PCR). The function of specific sites in the proximal promoter of MYCT1 in LSCC was measured by transient transfection, luciferase assays, electrophoretic mobility shift assay (EMSA) and chromatin immunoprecipitation assay (ChIP). Results The results suggested hypermethylation of 12 CpG sites of the promoter in both laryngeal cancer tissues and the laryngeal cancer line Hep-2 cell. The hypermethylation of the site CGCG (−695 to −692), which has been identified as the c-Myc binding site, was identified in laryngeal cancer tissues (59/73) compared to paired mucosa (13/73); in addition, statistical analysis revealed that the methylation status of this site significantly correlated with cancer cell differentiation(p < 0.01). The mRNA level of MYCT1 increased in Hep-2 cells treated with 5-aza-C (p < 0.01). The luciferase activity from mutant transfectants pGL3-MYCT1m (−852/+12, mut-695-C > A, mut-693-C > G) was significantly reduced compared with the wild type pGL3-MYCT1 (−852/+12), while the luciferase activity from wild transfectants pGL3-MYCT1 (−852/+12) rose after 5-aza treatment in Hep-2 cells. Finally, EMSA and ChIP confirmed that the methylation of the CGCG (−695 to −692) site prevented c-Myc from binding of the site and demethylation treatment of the 5′ flanking region of MYCT1 by 5-aza induced the increased occupation of the core promoter by c-Myc (p < 0.01). Conclusion In summary, this study concluded that hypermethylation contributed to the transcriptional down-regulation of MYCT1 and could inhibit cancer cell differentiation in LSCC. DNA methylation of the CGCG site (−695 to −692) of MYCT1 altered the promoter activity by interfering with its binding to c-Myc in LSCC. Epigenetic therapy of reactivating MYCT1 by 5-aza should be further evaluated in clinical trails of LSCC.
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Affiliation(s)
- Min Yang
- Department of Medical Genetics, China Medical University, Shenyang, P.R. China
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Soulet F, Kilarski WW, Antczak P, Herbert J, Bicknell R, Falciani F, Bikfalvi A. Gene signatures in wound tissue as evidenced by molecular profiling in the chick embryo model. BMC Genomics 2010; 11:495. [PMID: 20840761 PMCID: PMC2996991 DOI: 10.1186/1471-2164-11-495] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2010] [Accepted: 09/14/2010] [Indexed: 02/08/2023] Open
Abstract
BACKGROUND Modern functional genomic approaches may help to better understand the molecular events involved in tissue morphogenesis and to identify molecular signatures and pathways. We have recently applied transcriptomic profiling to evidence molecular signatures in the development of the normal chicken chorioallantoic membrane (CAM) and in tumor engrafted on the CAM. We have now extended our studies by performing a transcriptome analysis in the "wound model" of the chicken CAM, which is another relevant model of tissue morphogenesis. RESULTS To induce granulation tissue (GT) formation, we performed wounding of the chicken CAM and compared gene expression to normal CAM at the same stage of development. Matched control samples from the same individual were used. We observed a total of 282 genes up-regulated and 44 genes down-regulated assuming a false-discovery rate at 5% and a fold change > 2. Furthermore, bioinformatics analysis lead to the identification of several categories that are associated to organismal injury, tissue morphology, cellular movement, inflammatory disease, development and immune system. Endothelial cell data filtering leads to the identification of several new genes with an endothelial cell signature. CONCLUSIONS The chick chorioallantoic wound model allows the identification of gene signatures and pathways involved in GT formation and neoangiogenesis. This may constitute a fertile ground for further studies.
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15
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Li Y, Xu FL, Lu J, Saunders WS, Prochownik EV. Widespread genomic instability mediated by a pathway involving glycoprotein Ib alpha and Aurora B kinase. J Biol Chem 2010; 285:13183-92. [PMID: 20157117 DOI: 10.1074/jbc.m109.084913] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
c-Myc (Myc) oncoprotein induction of genomic instability (GI) contributes to its initial transforming function and subsequent tumor cell evolution. We describe here a pathway by which Myc, via its target protein glycoprotein Ibalpha (GpIb alpha), mediates GI. Proteomic profiling revealed that the serine/threonine kinase Aurora B is down-regulated by GpIb alpha in p53-deficient primary human fibroblasts. The phenotypes of Aurora B deficiency are strikingly reminiscent of Myc or GpIb alpha overexpression and include double-stranded DNA breaks, altered nuclear size and morphology, chromatin bridges, cleavage furrow regression, and tetraploidy. During mitosis, GpIb alpha and Aurora B redistribute to the cleavage furrow along with other cleavage furrow proteins. GpIb alpha overexpression at levels comparable with those seen in some tumor cells causes the dispersal of these proteins but not Aurora B, resulting in furrow regression and cytokinesis failure. Aurora B normalization redirects the mislocalized furrow proteins to their proper location, corrects the cleavage furrow abnormalities, and restores genomic stability. Aurora B thus appears necessary for a previously unrecognized function in guiding and positioning a number of key proteins, including GpIb alpha to the cleavage furrow. These findings underscore the importance of maintaining a delicate balance among cleavage furrow-associated proteins during mitosis. Suppression of Aurora B via GpIb alpha provides a unifying and mechanistic explanation for several types of Myc-mediated GI.
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Affiliation(s)
- Youjun Li
- Section of Hematology/Oncology, Children's Hospital of Pittsburgh of the University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania 15201, USA
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16
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Voisin V, Legault P, Ospina DPS, Ben-David Y, Rassart E. Gene profiling of the erythro- and megakaryoblastic leukaemias induced by the Graffi murine retrovirus. BMC Med Genomics 2010; 3:2. [PMID: 20102610 PMCID: PMC2843641 DOI: 10.1186/1755-8794-3-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2009] [Accepted: 01/26/2010] [Indexed: 12/02/2022] Open
Abstract
Background Acute erythro- and megakaryoblastic leukaemias are associated with very poor prognoses and the mechanism of blastic transformation is insufficiently elucidated. The murine Graffi leukaemia retrovirus induces erythro- and megakaryoblastic leukaemias when inoculated into NFS mice and represents a good model to study these leukaemias. Methods To expand our understanding of genes specific to these leukaemias, we compared gene expression profiles, measured by microarray and RT-PCR, of all leukaemia types induced by this virus. Results The transcriptome level changes, present between the different leukaemias, led to the identification of specific cancerous signatures. We reported numerous genes that may be potential oncogenes, may have a function related to erythropoiesis or megakaryopoiesis or have a poorly elucidated physiological role. The expression pattern of these genes has been further tested by RT-PCR in different samples, in a Friend erythroleukaemic model and in human leukaemic cell lines. We also screened the megakaryoblastic leukaemias for viral integrations and identified genes targeted by these integrations and potentially implicated in the onset of the disease. Conclusions Taken as a whole, the data obtained from this global gene profiling experiment have provided a detailed characterization of Graffi virus induced erythro- and megakaryoblastic leukaemias with many genes reported specific to the transcriptome of these leukaemias for the first time.
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Affiliation(s)
- Veronique Voisin
- Laboratoire de Biologie Moléculaire, Département des Sciences Biologiques, Centre BioMed, Université du Québec à Montréal, Case Postale 8888 Succursale Centre-ville, Montréal, QC, Canada
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17
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Li Y, Lu J, Prochownik EV. Modularity of the oncoprotein-like properties of platelet glycoprotein Ibalpha. J Biol Chem 2008; 284:1410-8. [PMID: 19017648 DOI: 10.1074/jbc.m806222200] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Glycoprotein Ib alpha (GpIbalpha), a trans-membrane glycoprotein, is expressed on the surface of megakaryocytes and platelets, where, in association with glycoprotein Ib beta, glycoprotein V, and glycoprotein IX, it normally forms the von Willebrand factor receptor (vWFR). A fully functional vWFR is necessary for platelet attachment, aggregation, and activation and has also been shown to regulate megakaryocyte ploidy. We have recently shown that the gene encoding GpIbalpha is a transcriptional target for the c-Myc oncoprotein and is more widely expressed than previously thought, with particularly high levels occurring in transformed cells. Indeed, GpIbalpha can substitute for c-Myc in promoting growth, transformation, and genomic instability. In the current work, we have demonstrated that, despite the promiscuous expression of GpIbalpha, other vWFR subunits remain largely restricted to megakaryocytes. We have characterized a panel of GpIbalpha mutants and shown that some regions of the protein essential for vWFR activity are not necessary for c-Myc-like functions. Specifically, the six C-terminal amino acids of the cytoplasmic domain, which mediate vWFR signaling, are entirely dispensible for the c-Myc-like functions of GpIbalpha. Instead, these require a more membrane-proximal filamin-binding domain. Also important is the GpIbalpha signal peptide, which, in the absence of other vWFR subunits, directs GpIbalpha to the endoplasmic reticulum rather than the membrane. Together, these results provide strong evidence that the domains of GpIbalpha mediating c-Myc-like functions are modular, genetically distinct, and independent of those involved in vWFR signaling.
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Affiliation(s)
- Youjun Li
- Section of Hematology/Oncology, Children's Hospital of Pittsburgh Pittsburgh, Pennsylvania 15213, USA
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18
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Niapour M, Yu Y, Berger SA. Regulation of Calpain Activity by c-Myc through Calpastatin and Promotion of Transformation in c-Myc-negative Cells by Calpastatin Suppression. J Biol Chem 2008; 283:21371-81. [DOI: 10.1074/jbc.m801462200] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
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19
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Li Y, Lu J, Cohen D, Prochownik EV. Transformation, genomic instability and senescence mediated by platelet/megakaryocyte glycoprotein Ibalpha. Oncogene 2007; 27:1599-609. [PMID: 17873907 DOI: 10.1038/sj.onc.1210794] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
GpIbalpha, a subunit of the von Willebrand factor receptor, functions during blood clotting to promote platelet adhesion and activation. GpIbalpha is widely expressed, is positively regulated by c-Myc and is essential for the promotion of c-Myc-mediated chromosomal instability. We now show that GpIbalpha is also a classical oncoprotein in which its deregulated expression leads to transformation, reduced growth factor requirements, increased resistance to apoptosis, and, in primary cells, p53-dependent senescence. Finally, GpIbalpha also promotes double-stranded DNA breaks, and induces profound nuclear dysmorphology, indicating that, in addition to its direct transforming function, it displays genotoxicity at several distinct levels. These findings identify novel functions for GpIbalpha and pathways through which c-Myc mediates transformation and global genomic destabilization.
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Affiliation(s)
- Y Li
- Section of Hematology/Oncology, Rangos Research Center, Children's Hospital of Pittsburgh, Pittsburgh, PA, USA
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20
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Kidd M, Modlin IM, Pfragner R, Eick GN, Champaneria MC, Chan AK, Camp RL, Mane SM. Small bowel carcinoid (enterochromaffin cell) neoplasia exhibits transforming growth factor-beta1-mediated regulatory abnormalities including up-regulation of C-Myc and MTA1. Cancer 2007; 109:2420-31. [PMID: 17469181 DOI: 10.1002/cncr.22725] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
BACKGROUND Although it is known that small intestinal carcinoids are derived from enterochromaffin (EC) cells, these cells remain poorly characterized and little is known of the growth regulatory mechanisms of these neuroendocrine cells. Down-regulation or loss of the transforming growth factor-beta1 (TGFbeta1) cytostatic program and activation of TGFbeta-mediated transcriptional networks is associated with uncontrolled growth and metastasis in other neural tumors, glioblastomas. Whether this phenomenon is common to small intestinal carcinoid tumors was investigated. METHODS The effects of TGFbeta1 on cultured normal EC cells (isolated by FACS sorting) and the neoplastic EC cell line, KRJ-I, was assessed using the MTT assay. The TGFbetaRII transcript and protein were identified in tumor cells and the effects of TGFbeta1 on SMAD2 phosphorylation and nuclear translocation quantified. The time-dependent response of SMAD4, SMAD7, c-Myc, and P21(WAF1/CIP1) protein expression and c-Myc and p21(WAF1/CIP1) transcript was measured in response to TGFbeta1 and the transcript expression of candidate downstream targets, MTA1 and E-cadherin, were assessed. RESULTS TGFbeta1 inhibited normal EC cell proliferation (IC(50) = 17 pM) but stimulated neoplastic EC cell proliferation (EC(50) = 22 pM). In tumor cells, significantly decreased transcript (P < .01) of TGFbetaRII was identified, but no receptor mutations were identified and protein expression was evident. TGFbeta1 (1 ng/mL) resulted in SMAD2 phosphorylation and <7% nuclear expression compared with 93% in normal EC cells. In neoplastic cells, TGFbeta1 (1 ng/mL) caused a decrease in SMAD4 (>16%, P < .05), whereas SMAD7 and c-Myc transcript and protein were respectively increased >21% (P < .05) and approximately 40% (P < .002). TGFbeta1 (1 ng/mL) also decreased p21(WAF1/CIP1) transcript by 60% (P < .001) and protein that was undetectable at 24 hours. Expression of the downstream targets of the c-Myc pathway, MTA1, was increased (20%) and E-cadherin decreased (30%). CONCLUSIONS The neoplastic EC cell is characterized by loss of TGFbeta-1-mediated growth inhibition and, similar to glioblastomas, utilizes the TGFbeta system to induce gene responses associated with growth promotion (c-Myc and the ERK pathway), invasion (E-cadherin), and metastasis (MTA1).
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Affiliation(s)
- Mark Kidd
- Department of Surgery, Yale University School of Medicine, New Haven, Connecticut 06520-8062, USA
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21
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Li Y, Lu J, Prochownik EV. c-Myc-mediated genomic instability proceeds via a megakaryocytic endomitosis pathway involving Gp1balpha. Proc Natl Acad Sci U S A 2007; 104:3490-5. [PMID: 17360671 PMCID: PMC1805544 DOI: 10.1073/pnas.0610163104] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Genomic instability (GI) is essential for the initiation and evolution of many cancers and often precedes frank neoplastic conversion. Although GI can occur at several levels, the most conspicuous examples involve gains or losses of entire chromosomes (aneuploidy), the antecedent of which may be whole genome duplication (tetraploidy). Through largely undefined mechanisms, the c-Myc oncoprotein and its downstream target, MTMC1, promote tetraploidy and other forms of GI. In myeloid cells, c-Myc and MTMC1 also regulate a common, small subset of c-Myc target genes including GP1Balpha, which encodes a subunit of the von Willebrand's factor receptor complex that mediates platelet adhesion and aggregation. Gp1balpha also participates in megakaryocyte endomitosis, a form of controlled and precise whole-genome amplification. In this article, we show that both c-Myc and MTMC1 strongly up-regulate Gp1balpha concurrent with their promotion of tetraploidy. shRNA-mediated inhibition of Gp1balpha prevents tetraploidy by both c-Myc and MTMC1, whereas Gp1balpha overexpression alone is sufficient to induce tetraploidy in established and primary cells. Once acquired, tetraploidy persists in most cases examined. Our results indicate that chromosome-level GI, induced by c-Myc overexpression, proceeds by means of the sequential up-regulation of MTMC1 and Gp1balpha and further suggest that the pathways leading to megakaryocytic endomitosis and c-Myc-induced tetraploidy are mechanistically linked by their reliance on Gp1balpha.
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Affiliation(s)
- Youjun Li
- *Section of Hematology/Oncology, Children's Hospital of Pittsburgh
| | - Jie Lu
- Department of Molecular Genetics and Biochemistry, University of Pittsburgh Medical Center, and
| | - Edward V. Prochownik
- *Section of Hematology/Oncology, Children's Hospital of Pittsburgh
- Department of Molecular Genetics and Biochemistry, University of Pittsburgh Medical Center, and
- University of Pittsburgh Cancer Institute, University of Pittsburgh, Pittsburgh, PA 15213
- To whom correspondence should be addressed at:
Section of Hematology/Oncology, Rangos Research Center, Room 8124, Children's Hospital of Pittsburgh, 3460 Fifth Avenue, Pittsburgh, PA 15213. E-mail:
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22
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De Bleser P, Hooghe B, Vlieghe D, van Roy F. A distance difference matrix approach to identifying transcription factors that regulate differential gene expression. Genome Biol 2007; 8:R83. [PMID: 17504544 PMCID: PMC1929144 DOI: 10.1186/gb-2007-8-5-r83] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2006] [Revised: 03/30/2007] [Accepted: 05/16/2007] [Indexed: 01/10/2023] Open
Abstract
We introduce a method that considers target genes of a transcription factor, and searches for transcription factor binding sites (TFBSs) of secondary factors responsible for differential responses among these targets. Based on the distance difference matrix concept, the method simultaneously integrates statistical overrepresentation and co-occurrence of TFBSs. Our approach is validated on datasets of differentially regulated human genes and is shown to be highly effective in detecting TFBSs responsible for the observed differential gene expression.
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Affiliation(s)
- Pieter De Bleser
- Bioinformatics Core, VIB, B-9052 Ghent, Belgium
- Department for Molecular Biomedical Research, VIB, B-9052 Ghent, Belgium
- Department of Molecular Biology, Ghent University, B-9052 Ghent, Belgium
| | - Bart Hooghe
- Bioinformatics Core, VIB, B-9052 Ghent, Belgium
- Department for Molecular Biomedical Research, VIB, B-9052 Ghent, Belgium
- Department of Molecular Biology, Ghent University, B-9052 Ghent, Belgium
| | - Dominique Vlieghe
- Bioinformatics Core, VIB, B-9052 Ghent, Belgium
- Department for Molecular Biomedical Research, VIB, B-9052 Ghent, Belgium
- Department of Molecular Biology, Ghent University, B-9052 Ghent, Belgium
| | - Frans van Roy
- Department for Molecular Biomedical Research, VIB, B-9052 Ghent, Belgium
- Department of Molecular Biology, Ghent University, B-9052 Ghent, Belgium
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