DOCSLIB.ORG

Function and Regulatory Mechanisms of the Candidate Tumor Suppressor Receptor Protein Tyrosine Phosphatase Gamma (PTPRG) in Breast Cancer Cells

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Function and Regulatory Mechanisms of the Candidate Tumor Suppressor Receptor Protein Tyrosine Phosphatase Gamma (PTPRG) in Breast Cancer Cells ANTICANCER RESEARCH 30: 1937-1946 (2010) Function and Regulatory Mechanisms of the Candidate Tumor Suppressor Receptor Protein Tyrosine Phosphatase Gamma (PTPRG) in Breast Cancer Cells SHERRY T. SHU1*, YASURO SUGIMOTO1,2*, SULING LIU1, HSIANG-LIN CHANG1, WEIPING YE1, LI-SHU WANG1, YI-WEN HUANG1, PEARLLY YAN2,3 and YOUNG C. LIN1,2 1Laboratory of Reproductive and Molecular Endocrinology, Department of Veterinary Biosciences, College of Veterinary Medicine, 2The Ohio State University Comprehensive Cancer Center, and 3Department of Molecular Virology, Immunology and Medical Genetics, The Ohio State University, Columbus, OH 43210-1093, U.S.A. Abstract. Background: Protein phosphorylation is one of the transfected with vector alone. Similarly, overexpression of essential steps in cell signaling, and aberrant phosphorylation PTPRG also delayed the re-entry of breast cancer cells into is a common event in human cancer. The expression of the cell cycle after serum starvation, and reduced the receptor type protein tyrosine phosphatase gamma (PTPRG) phosphorylation levels ERK1/2 in MCF-7 cells. In addition, in normal breast is found to be ~50-60% higher than that of methylation assays in PTPRG promoter in breast cancer cell breast tumor tissue. Overexpression of PTPRG inhibits lines (including SK-Br-3) revealed an aberrant methylation anchorage-independent growth and proliferation of breast pattern. When SK-Br-3 and MCF-7 cells were treated with cancer cells. To understand the tumor suppression deoxy-5-azacytidine (DAC) and trichostatin A (TSA), these characteristics of PTPRG, we studied its tumor suppressive compounds reactivated the expression of PTPRG, suggesting function in an athymic mouse model and evaluated factors that an epigenetic control on its expression. Conclusion: Our can potentially regulate its expression in breast cancer cells. results indicated that PTPRG inhibited breast tumor formation Materials and Methods: To investigate the function of PTPRG in vivo; PTPRG may up-regulate p21cip and p27kip proteins in vivo, athymic nude mice were implanted with MCF-7 cells through the ERK1/2 pathway. This study also showed overexpressing PTPRG. For in vitro study, protein levels of cell methylation-mediated silencing of PTPRG in breast cancer cycle regulators, cell cycle re-entry, and the phosphorylation cell lines. These data indicate that PTPRG exhibits the levels of extracellular signal-regulated protein kinases 1/2 characteristics of a breast tumor suppressor. (ERK1/2) were examined. In addition, methylation assays were conducted to investigate the epigenetic modification on the Tyrosine phosphorylation is an important cellular process in promoter of PTPRG. Results: Athymic nude mice bearing multicellular eukaryotes (1). Two major groups of enzymes are MCF-7 cells overexpressing PTPRG showed a reduction in involved in regulating tyrosine phosphorylation: protein tumor burden in comparison to animals implanted with MCF- tyrosine phophatases (PTPs) and protein tyrosine kinases 7 cells transfected with vector alone. When these two cell lines (PTKs). A number of PTKs have been functionally were studied in an in vitro system, elevated mRNA and protein characterized and several PTK inhibitors have been studied in levels of cell cycle regulators, p21cip and p27kip were detected clinical trials for their therapeutic values (2, 3). PTPs, however, in MCF-7 cells overexpressing PTPRG compared to cells are less well-studied, although their involvement in cell proliferation and cell transformation has been reported (4, 5). PTPs can be classified into four distinct families based on the amino acid sequences of their catalytic domains (1, 6). *Both authors contributed equally to this work. The class I, cysteine-based PTP family can be further classified into two subfamilies depending on their cellular Correspondence to: Young C. Lin, DVM, Ph.D., 1925 Coffey Road, localization, namely non-transmembrane PTP subtype Columbus, OH 43210-1093, U.S.A. Tel: +1 6142929706, Fax: +1 6142926473, e-mail: [email protected] (NTPTPs) and receptor–like PTP subtype (RPTPs). The NTPTPs contain only intracellular motif with one catalytic Key Words: PTPG, breast cancer, tumor suppressor, cell cycle domain (PTP domain), whereas RPTPs contain extracellular, regulators. transmembrane and intracellular motifs with one or more PTP 0250-7005/2010 $2.00+.40 1937 ANTICANCER RESEARCH 30: 1937-1946 (2010) domains. Reports have shown that PTPs play important roles Materials and Methods in transformation and tumorigenesis. For examples, SHP2, PTP1B, and low molecular weight PTP (LMW-PTP) Mouse xenograft model. Female NCr-nu/nu athymic mice at 5-7 overexpressed in cancer cells promote oncogenesis and tumor weeks of age were purchased from the National Cancer Institute (Frederic, MD, USA). The animals received food and water (ad progression (7, 8). However, reports have also demonstrated libitum) and were housed in a pathogen-free environment. All animal the possible mechanisms of how PTPs repress cell growth studies were performed according to guidelines approved by The through cell cycle regulation. PTPH1/PTPN3 suppresses cell Ohio State University ILACUC. Sub-confluent M7-PCR and M7- cycle progression through dephosphorylation of valosin- PTPRG cells were harvested, and cell viability was determined by containing protein (VCP/p97), an ATPase that mediates trypan blue exclusion assay. Single cell suspension (5×106 cells/ml) proteasomal degradation (9). Overexpression of protein of >90% viability was washed using PBS, mixed in Matrigel (10 tyrosine phosphatase receptor-type O (PTPRO) can delay the mg/ml), and injected into mice subcutaneously. In addition, a 100 day-release pellet containing 10 mg of estradiol-17β (E , 6.0 re-entry of lung cancer cells into the cell cycle (10). Rat PTP 2 μg/day/kg body weight) (Innovative Research of America, FL, USA) η (PTPRJ) exerts growth inhibition activity through was implanted subcutaneously to facilitate tumor formation (18). kip stabilization of cyclin-dependent kinase inhibitor p27 (11). Mice were weighed and tumor formation was monitored by Receptor type protein tyrosine phosphatase gamma (PTPRG) measuring tumors with calipers every 3 days. Tumor volumes were is an RPTP and is broadly expressed in many different organs calculated using the formula, L × W2/2 = mm3, where L is the length (12). PTPRG gene located at chromosome 3p14.2 has been and W is the width of the tumor (18). The mice were sacrificed on implicated as a candidate tumor suppressor gene based on day 55 and a whole-body tumor scan was performed using a 4.7 Tesla/40cm magnetic resonance imaging (MRI) system controlled by loss of heterozygosity studies in renal cancer (13). Reduced a Bruker Advance Console, at the OSU Animal MRI Facility. Tumors PTPRG expression in lung, ovarian and breast cancer cells were processed for histologic analysis and evaluated by the OSU has been reported (14-16). However, little is known about the Histology/Immunohistochemistry Core service. functions and regulation of PTPRG and how it regulates cell cycle events in breast cancer cells. Cell lines and cell treatment. MCF-7, SK-Br-3, MDA-MB-453 and During cancer development and progression, tumor MCF-10A were purchased from American Type Culture Collection, VA. suppressor genes are increasingly silenced, leading to growth MCF-10A was maintained in phenol red-free low calcium (0.04 mM) advantage in the cancerous cells. One avenue of gene silencing Dulbecco’s modified Eagle’s medium and Ham’s F12 Medium (1:1) (DMEM/F12) supplemented with 10% (v/v) Chelex-100 (Bio-Rad is by promoter epigenetic modulations. Promoters of PTPRO Laboratory, CA, USA) –treated fetal calf serum (FCS), 10 μg/ml human and SHP1 were methylated in lung cancer and lymphoma, recombinant epidermal growth factor (EGF) and 100 μg/ml cholera respectively, and the methylation levels were shown to be toxin (both from Invitrogen, CA, USA). MCF-7 cells stably transfected correlated with the loss of gene transcripts in these cancer with full length PTPRG cDNA (M7-PTPRG cells) or stably transfected samples (10, 17). In this study, we also investigated the with pCR3.1 vector alone (M7-PCR cells) were established and selected methylation patterns in the PTPRG promoter region in breast by use of G-418 as previously described (5). M7-PTPRG, M7-PCR, cancer cell lines and examined how the methylation and gene MCF-7, SK-Br-3, and MDA-MB-453 cells were maintained in DMEM/F-12 (1:1) supplemented with 5% (v/v) FBS (final expression patterns were altered by deoxy-5-azacytidine (DAC) concentration). For methylation assay, cells were treated with 10 μM and trichostatin A (TSA) treatments. DAC (Sigma, MO, USA), 1 μM TSA (Sigma), the combined treatment Previously, we have established and characterized MCF-7 of DAC and TSA (10 μM and 1 μM, respectively), or vehicle for 4 days. cells stably transfected with full length PTPRG cDNA (M7- PTPRG cells) (5). PTPRG levels for both mRNA and protein Western blot assays. Whole cell lysate from M7-PTPRG and M7- expression were showed to be elevated in the PTPRG- PCR cells were separated by SDS-PAGE, and proteins were transfected cells when compared to cells transfected with transferred onto polyvinylidene fluoride (PVDF) membranes. vector alone (M7-PCR cells). Overexpression of PTPRG Enhanced chemiluminescence (ECL) plus™ reagents (Amersham reduces anchorage-independent colonization and proliferation Biosciences, NJ, USA) were used to detect the signals of the following proteins: anti-PTPRG (5), anti-p27kip (BD Biosciences, of breast cancer cell lines (5), indicating that PTPRG may CA, USA), anti-actin (Santa Cruz Biotechnology, CA, USA), anti- function as an important modulator of tumorigenesis in p21cip, anti-ERK1/2, and anti-phosphorylated-ERK1/2 (Cell human breast. In this report, we provide additional in vivo Signaling Technology, MA, USA). The chemiluminescent signals evidence to support the tumor suppressive function of PTPRG were acquired by an LAS-3000 imaging system (Fujifilm, CT, and how it may play a role in the cell cycle re-entry USA). The splicing of images is for illustration purposes.
Load more

Recommended publications
  • The Regulatory Roles of Phosphatases in Cancer
    Oncogene (2014) 33, 939–953 & 2014 Macmillan Publishers Limited All rights reserved 0950-9232/14 www.nature.com/onc REVIEW The regulatory roles of phosphatases in cancer J Stebbing1, LC Lit1, H Zhang, RS Darrington, O Melaiu, B Rudraraju and G Giamas The relevance of potentially reversible post-translational modifications required for controlling cellular processes in cancer is one of the most thriving arenas of cellular and molecular biology. Any alteration in the balanced equilibrium between kinases and phosphatases may result in development and progression of various diseases, including different types of cancer, though phosphatases are relatively under-studied. Loss of phosphatases such as PTEN (phosphatase and tensin homologue deleted on chromosome 10), a known tumour suppressor, across tumour types lends credence to the development of phosphatidylinositol 3--kinase inhibitors alongside the use of phosphatase expression as a biomarker, though phase 3 trial data are lacking. In this review, we give an updated report on phosphatase dysregulation linked to organ-specific malignancies. Oncogene (2014) 33, 939–953; doi:10.1038/onc.2013.80; published online 18 March 2013 Keywords: cancer; phosphatases; solid tumours GASTROINTESTINAL MALIGNANCIES abs in sera were significantly associated with poor survival in Oesophageal cancer advanced ESCC, suggesting that they may have a clinical utility in Loss of PTEN (phosphatase and tensin homologue deleted on ESCC screening and diagnosis.5 chromosome 10) expression in oesophageal cancer is frequent, Cao et al.6 investigated the role of protein tyrosine phosphatase, among other gene alterations characterizing this disease. Zhou non-receptor type 12 (PTPN12) in ESCC and showed that PTPN12 et al.1 found that overexpression of PTEN suppresses growth and protein expression is higher in normal para-cancerous tissues than induces apoptosis in oesophageal cancer cell lines, through in 20 ESCC tissues.
    [Show full text]
  • Pdf/Infopackage Kinex.Pdf for a Com- Domain Inhibition (15)
    Protein Tyrosine Phosphatase Receptor Type γ Is a JAK Phosphatase and Negatively Regulates Leukocyte Integrin Activation This information is current as Michela Mirenda, Lara Toffali, Alessio Montresor, Giovanni of October 1, 2021. Scardoni, Claudio Sorio and Carlo Laudanna J Immunol 2015; 194:2168-2179; Prepublished online 26 January 2015; doi: 10.4049/jimmunol.1401841 http://www.jimmunol.org/content/194/5/2168 Downloaded from Supplementary http://www.jimmunol.org/content/suppl/2015/01/23/jimmunol.140184 Material 1.DCSupplemental http://www.jimmunol.org/ References This article cites 46 articles, 16 of which you can access for free at: http://www.jimmunol.org/content/194/5/2168.full#ref-list-1 Why The JI? Submit online. • Rapid Reviews! 30 days* from submission to initial decision • No Triage! Every submission reviewed by practicing scientists by guest on October 1, 2021 • Fast Publication! 4 weeks from acceptance to publication *average Subscription Information about subscribing to The Journal of Immunology is online at: http://jimmunol.org/subscription Permissions Submit copyright permission requests at: http://www.aai.org/About/Publications/JI/copyright.html Email Alerts Receive free email-alerts when new articles cite this article. Sign up at: http://jimmunol.org/alerts The Journal of Immunology is published twice each month by The American Association of Immunologists, Inc., 1451 Rockville Pike, Suite 650, Rockville, MD 20852 Copyright © 2015 by The American Association of Immunologists, Inc. All rights reserved. Print ISSN: 0022-1767 Online ISSN: 1550-6606. The Journal of Immunology Protein Tyrosine Phosphatase Receptor Type g Is a JAK Phosphatase and Negatively Regulates Leukocyte Integrin Activation Michela Mirenda,* Lara Toffali,*,† Alessio Montresor,*,† Giovanni Scardoni,† Claudio Sorio,* and Carlo Laudanna*,† Regulation of signal transduction networks depends on protein kinase and phosphatase activities.
    [Show full text]
  • A Homozygous Deletion Within the Carbonic Anhydrase-Like Domain of the Ptprg Gene in Murine L-Cells1
    (CANCER RESEARCH 53. 14«)»-1502.April1. 1993| Advances in Brief A Homozygous Deletion within the Carbonic Anhydrase-like Domain of the Ptprg Gene in Murine L-Cells1 Kishore K. Wary, Zhuangwei Lou, Arthur M. Buchberg, Linda D. Siracusa, Teresa Druck, Sal LaForgia, and Kay Huebner2 Jefferson Cancer Instilare. Thomas Jefferson Medical College, Philadelphia. Pennsylvania ¡9ÃŒ07 Abstract and murine predicted amino acid sequences for this isoform are greater than 90% identical: the Ptprg gene contains a single trans- Protein tyrosine phosphatases, on purely theoretical grounds, were sug membrane domain and two tandem tyrosine phosphatase domains. gested as possible tumor suppressor genes, and receptor protein tyrosine The extracellular region contains one fibronectin type repeat and. like phosphatase 7 (PTPRG ) has been proposed, on the basis of its location at the PTPRZ gene (7).' an NH2-terminal region of 266 amino acids with human chromosome region 3pl4.2, specifically as a tumor suppressor gene —¿30%sequence similarity to members of the carbonic anhydrase for renal cell carcinoma. We have isolated murine genomic and complementary DNA clones for enzyme family (8). analysis and mapping of the murine Ptprg locus; interspecific backcross During an investigation of the genomic organization of human and analysis showed that the Ptprg locus maps to the centramene region of mouse Ptprg loci, we noted extensive polymorphism of the murine mouse chromosome 14. We also observed a homozygous, intragenic dele Píprglocus5 and a homozygous deletion of a portion of the CA-like tion in the Ptprg gene in all donai derivatives of the original I.-cell strain, domain in murine L-cell lines, which we undertook to describe in a methylcholanthrene-treated mouse connective tissue cell line which pro detail, since homozygous deletion of a gene is one of the hallmarks of duces sarcomas in syngeneic mice.
    [Show full text]
  • Supplementary Data
    Progressive Disease Signature Upregulated probes with progressive disease U133Plus2 ID Gene Symbol Gene Name 239673_at NR3C2 nuclear receptor subfamily 3, group C, member 2 228994_at CCDC24 coiled-coil domain containing 24 1562245_a_at ZNF578 zinc finger protein 578 234224_at PTPRG protein tyrosine phosphatase, receptor type, G 219173_at NA NA 218613_at PSD3 pleckstrin and Sec7 domain containing 3 236167_at TNS3 tensin 3 1562244_at ZNF578 zinc finger protein 578 221909_at RNFT2 ring finger protein, transmembrane 2 1552732_at ABRA actin-binding Rho activating protein 59375_at MYO15B myosin XVB pseudogene 203633_at CPT1A carnitine palmitoyltransferase 1A (liver) 1563120_at NA NA 1560098_at AKR1C2 aldo-keto reductase family 1, member C2 (dihydrodiol dehydrogenase 2; bile acid binding pro 238576_at NA NA 202283_at SERPINF1 serpin peptidase inhibitor, clade F (alpha-2 antiplasmin, pigment epithelium derived factor), m 214248_s_at TRIM2 tripartite motif-containing 2 204766_s_at NUDT1 nudix (nucleoside diphosphate linked moiety X)-type motif 1 242308_at MCOLN3 mucolipin 3 1569154_a_at NA NA 228171_s_at PLEKHG4 pleckstrin homology domain containing, family G (with RhoGef domain) member 4 1552587_at CNBD1 cyclic nucleotide binding domain containing 1 220705_s_at ADAMTS7 ADAM metallopeptidase with thrombospondin type 1 motif, 7 232332_at RP13-347D8.3 KIAA1210 protein 1553618_at TRIM43 tripartite motif-containing 43 209369_at ANXA3 annexin A3 243143_at FAM24A family with sequence similarity 24, member A 234742_at SIRPG signal-regulatory protein gamma
    [Show full text]
  • Supplementary Table 2
    Supplementary Table 2. Differentially Expressed Genes following Sham treatment relative to Untreated Controls Fold Change Accession Name Symbol 3 h 12 h NM_013121 CD28 antigen Cd28 12.82 BG665360 FMS-like tyrosine kinase 1 Flt1 9.63 NM_012701 Adrenergic receptor, beta 1 Adrb1 8.24 0.46 U20796 Nuclear receptor subfamily 1, group D, member 2 Nr1d2 7.22 NM_017116 Calpain 2 Capn2 6.41 BE097282 Guanine nucleotide binding protein, alpha 12 Gna12 6.21 NM_053328 Basic helix-loop-helix domain containing, class B2 Bhlhb2 5.79 NM_053831 Guanylate cyclase 2f Gucy2f 5.71 AW251703 Tumor necrosis factor receptor superfamily, member 12a Tnfrsf12a 5.57 NM_021691 Twist homolog 2 (Drosophila) Twist2 5.42 NM_133550 Fc receptor, IgE, low affinity II, alpha polypeptide Fcer2a 4.93 NM_031120 Signal sequence receptor, gamma Ssr3 4.84 NM_053544 Secreted frizzled-related protein 4 Sfrp4 4.73 NM_053910 Pleckstrin homology, Sec7 and coiled/coil domains 1 Pscd1 4.69 BE113233 Suppressor of cytokine signaling 2 Socs2 4.68 NM_053949 Potassium voltage-gated channel, subfamily H (eag- Kcnh2 4.60 related), member 2 NM_017305 Glutamate cysteine ligase, modifier subunit Gclm 4.59 NM_017309 Protein phospatase 3, regulatory subunit B, alpha Ppp3r1 4.54 isoform,type 1 NM_012765 5-hydroxytryptamine (serotonin) receptor 2C Htr2c 4.46 NM_017218 V-erb-b2 erythroblastic leukemia viral oncogene homolog Erbb3 4.42 3 (avian) AW918369 Zinc finger protein 191 Zfp191 4.38 NM_031034 Guanine nucleotide binding protein, alpha 12 Gna12 4.38 NM_017020 Interleukin 6 receptor Il6r 4.37 AJ002942
    [Show full text]
  • Receptor Protein Tyrosine Phosphatases Control Purkinje Neuron Firing
    Receptor protein tyrosine phosphatases control Purkinje neuron firing Alexander S. Brown1, Pratap Meera2, Gabe Quinones1, Jessica Magri1, Thomas S. Otis3, Stefan M. Pulst4, and Anthony E. Oro1,5 1Program in Epithelial Biology Stanford University School of Medicine, Stanford CA, 2Department of Neurobiology University of California Los Angeles, Los Angeles CA 3Sainsbury Wellcome Centre for Neural Circuits and Behavior, University College London, London, United Kingdom 4Department of Neurology, University of Utah Medical Center, Salt Lake City, UT 5To whom correspondence should be addressed: Anthony E.Oro ( [email protected]) . Abstract (173/200 words): Spinocerebellar ataxias (SCA) are a genetically heterogeneous family of cerebellar neurodegenerative diseases characterized by abnormal firing of Purkinje neurons and degeneration. We recently demonstrated the slowed firing rates seen in several SCAs share a common etiology of hyper-activation of the Src family of non-receptor tyrosine kinases (SFKs)1. However, because of the lack of effective neuroactive, clinically available SFK inhibitors, alternative mechanisms to modulate SFK activity are needed. Previous studies demonstrate that SFK activity can be enhanced by the removal of inhibitory phospho-marks by receptor-protein-tyrosine phosphatases (RPTPs)2,3. In this Extra View we show that MTSS1 inhibits SFK activity through the binding and inhibition of a subset of the RPTP family members. RPTP activity normally results in SFK activation in vitro, and lowering RPTP activity in cerebellar slices using recently described RPTP peptide inhibitors increases the suppressed Purkinje neuron basal firing rates seen in two different SCA models. Together these results identify RPTPs as novel effectors of cerebellar activity, extending the MTSS1/SFK regulatory circuit we previously described and expanding the therapeutic targets for SCA patients.
    [Show full text]
  • Current Views on the Interplay Between Tyrosine Kinases and Phosphatases in Chronic Myeloid Leukemia
    cancers Review Current Views on the Interplay between Tyrosine Kinases and Phosphatases in Chronic Myeloid Leukemia Christian Boni and Claudio Sorio * Department of Medicine, General Pathology Division, University of Verona, 37134 Verona, Italy; [email protected] * Correspondence: [email protected]; Tel.: +39-045-802-7688 Simple Summary: The chromosomal alteration t(9;22) generating the BCR-ABL1 fusion protein represents the principal feature that distinguishes some types of leukemia. An increasing number of articles have focused the attention on the relevance of protein phosphatases and their potential role in the control of BCR-ABL1-dependent or -independent signaling in different areas related to the biology of chronic myeloid leukemia. Herein, we discuss how tyrosine and serine/threonine protein phosphatases may interact with protein kinases, in order to regulate proliferative signal cascades, quiescence and self-renewals on leukemic stem cells, and drug-resistance, indicating how BCR-ABL1 can (directly or indirectly) affect these critical cells behaviors. We provide an updated review of the literature on the function of protein phosphatases and their regulation mechanism in chronic myeloid leukemia. Abstract: Chronic myeloid leukemia (CML) is a myeloproliferative disorder characterized by BCR- ABL1 oncogene expression. This dysregulated protein-tyrosine kinase (PTK) is known as the principal driver of the disease and is targeted by tyrosine kinase inhibitors (TKIs). Extensive documentation has Citation: Boni, C.; Sorio, C. Current elucidated how the transformation of malignant cells is characterized by multiple genetic/epigenetic Views on the Interplay between changes leading to the loss of tumor-suppressor genes function or proto-oncogenes expression. Tyrosine Kinases and Phosphatases in The impairment of adequate levels of substrates phosphorylation, thus affecting the balance PTKs Chronic Myeloid Leukemia.
    [Show full text]
  • The Role of Protein-Tyrosine Phosphatases for Sensitivity and Resistance of CML-Cells to Tyrosine-Kinase Inhibitors
    The role of protein-tyrosine phosphatases for sensitivity and resistance of CML-cells to tyrosine-kinase inhibitors Dissertation zur Erlangung des akademischen Grades „doctor rerum naturalium“ (Dr. rer. nat.) vorgelegt dem Rat der Fakultät für Biowissenschaften der Friedrich-Schiller-Universität Jena von Diplom Biochemikerin Julia Drube geboren am 23. November 1982 in Trier Tag der öffentlichen Verteidigung 29.05.2018 Gutachter 1. apl. Prof. Dr. Frank-Dietmar Böhmer (Jena, Deutschland) 2. PD Dr. Christian Kosan (Jena, Deutschland) 3. Prof. Dr. Wiljan J. A. J. Hendriks (Nijmegen, Niederlande) I Zusammenfassung Die Chronisch myeloische Leukämie (CML) ist eine Krankheit des hämatopoetischen Systems, welche durch die Expression von BCR-ABL1 ausgelöst wird. Dieses Onkoprotein ist eine konstitutiv aktive Protein-Tyrosinkinase (PTK), welche in Zellen Signalwege anschaltet, die unkontrolliertes Wachstum und Überleben steuern. Aus diesem Grund kann die CML mit spezifischen Tyrosinkinase-Inhibitoren (TKI) behandelt werden, die die Funktion von BCR-ABL1 hemmen. Imatinib, der erste TKI der in der Klinik Anwendung fand, hat die Therapie der CML revolutioniert: Die Patienten hatten gute Ansprechraten und viele ein gutes Langzeitüberleben mit vergleichsweise wenig Nebenwirkungen. Die Einführung von Nilotinib, eines noch potenteren Zweit-Generationen-TKI führte zu einem weiter verbesserten Wirkprofil mit schnellerem und tieferem Ansprechen. Ein Teil der Patienten wird voraussichtlich die Therapie absetzen können und trotzdem in therapiefreier Remission bleiben. Gegenstand aktueller klinischen Studien ist die Optimierung der Therapie und die genauere Untersuchung der Voraussetzungen für ein erfolgreiches Absetzen der TKI. Es ist bereits bekannt, dass ein besonders schnelles Erreichen einer anhaltenden, tiefen molekularen Remission sich günstig auf eine funktionelle Heilung auswirkt. Aus diesem Grund ist es von großem Interesse, die molekularen Mechanismen besser zu verstehen, welche das Erreichen der tiefen molekularen Remission beeinflussen.
    [Show full text]
  • Lipid Phosphatases Identified by Screening a Mouse Phosphatase Shrna Library Regulate T-Cell Differentiation and Protein Kinase
    Lipid phosphatases identified by screening a mouse PNAS PLUS phosphatase shRNA library regulate T-cell differentiation and Protein kinase B AKT signaling Liying Guoa, Craig Martensb, Daniel Brunob, Stephen F. Porcellab, Hidehiro Yamanea, Stephane M. Caucheteuxa, Jinfang Zhuc, and William E. Paula,1 aCytokine Biology Unit, cMolecular and Cellular Immunoregulation Unit, Laboratory of Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892; and bGenomics Unit, Research Technologies Section, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT 59840 Contributed by William E. Paul, March 27, 2013 (sent for review December 18, 2012) Screening a complete mouse phosphatase lentiviral shRNA library production (10, 11). Conversely, constitutive expression of active using high-throughput sequencing revealed several phosphatases AKT leads to increased proliferation and enhanced Th1/Th2 cy- that regulate CD4 T-cell differentiation. We concentrated on two lipid tokine production (12). phosphatases, the myotubularin-related protein (MTMR)9 and -7. The amount of PI[3,4,5]P3 and the level of AKT activation are Silencing MTMR9 by shRNA or siRNA resulted in enhanced T-helper tightly controlled by several mechanisms, including breakdown of (Th)1 differentiation and increased Th1 protein kinase B (PKB)/AKT PI[3,4,5]P3, down-regulation of the amount and activity of PI3K, phosphorylation while silencing MTMR7 caused increased Th2 and and the dephosphorylation of AKT (13). PTEN is a major negative Th17 differentiation and increased AKT phosphorylation in these regulator of PI[3,4,5]P3. It removes the 3-phosphate from the cells.
    [Show full text]
  • Live-Cell Imaging Rnai Screen Identifies PP2A–B55α and Importin-Β1 As Key Mitotic Exit Regulators in Human Cells
    LETTERS Live-cell imaging RNAi screen identifies PP2A–B55α and importin-β1 as key mitotic exit regulators in human cells Michael H. A. Schmitz1,2,3, Michael Held1,2, Veerle Janssens4, James R. A. Hutchins5, Otto Hudecz6, Elitsa Ivanova4, Jozef Goris4, Laura Trinkle-Mulcahy7, Angus I. Lamond8, Ina Poser9, Anthony A. Hyman9, Karl Mechtler5,6, Jan-Michael Peters5 and Daniel W. Gerlich1,2,10 When vertebrate cells exit mitosis various cellular structures can contribute to Cdk1 substrate dephosphorylation during vertebrate are re-organized to build functional interphase cells1. This mitotic exit, whereas Ca2+-triggered mitotic exit in cytostatic-factor- depends on Cdk1 (cyclin dependent kinase 1) inactivation arrested egg extracts depends on calcineurin12,13. Early genetic studies in and subsequent dephosphorylation of its substrates2–4. Drosophila melanogaster 14,15 and Aspergillus nidulans16 reported defects Members of the protein phosphatase 1 and 2A (PP1 and in late mitosis of PP1 and PP2A mutants. However, the assays used in PP2A) families can dephosphorylate Cdk1 substrates in these studies were not specific for mitotic exit because they scored pro- biochemical extracts during mitotic exit5,6, but how this relates metaphase arrest or anaphase chromosome bridges, which can result to postmitotic reassembly of interphase structures in intact from defects in early mitosis. cells is not known. Here, we use a live-cell imaging assay and Intracellular targeting of Ser/Thr phosphatase complexes to specific RNAi knockdown to screen a genome-wide library of protein substrates is mediated by a diverse range of regulatory and targeting phosphatases for mitotic exit functions in human cells. We subunits that associate with a small group of catalytic subunits3,4,17.
    [Show full text]
  • Phosphatases Page 1
    Phosphatases esiRNA ID Gene Name Gene Description Ensembl ID HU-05948-1 ACP1 acid phosphatase 1, soluble ENSG00000143727 HU-01870-1 ACP2 acid phosphatase 2, lysosomal ENSG00000134575 HU-05292-1 ACP5 acid phosphatase 5, tartrate resistant ENSG00000102575 HU-02655-1 ACP6 acid phosphatase 6, lysophosphatidic ENSG00000162836 HU-13465-1 ACPL2 acid phosphatase-like 2 ENSG00000155893 HU-06716-1 ACPP acid phosphatase, prostate ENSG00000014257 HU-15218-1 ACPT acid phosphatase, testicular ENSG00000142513 HU-09496-1 ACYP1 acylphosphatase 1, erythrocyte (common) type ENSG00000119640 HU-04746-1 ALPL alkaline phosphatase, liver ENSG00000162551 HU-14729-1 ALPP alkaline phosphatase, placental ENSG00000163283 HU-14729-1 ALPP alkaline phosphatase, placental ENSG00000163283 HU-14729-1 ALPPL2 alkaline phosphatase, placental-like 2 ENSG00000163286 HU-07767-1 BPGM 2,3-bisphosphoglycerate mutase ENSG00000172331 HU-06476-1 BPNT1 3'(2'), 5'-bisphosphate nucleotidase 1 ENSG00000162813 HU-09086-1 CANT1 calcium activated nucleotidase 1 ENSG00000171302 HU-03115-1 CCDC155 coiled-coil domain containing 155 ENSG00000161609 HU-09022-1 CDC14A CDC14 cell division cycle 14 homolog A (S. cerevisiae) ENSG00000079335 HU-11533-1 CDC14B CDC14 cell division cycle 14 homolog B (S. cerevisiae) ENSG00000081377 HU-06323-1 CDC25A cell division cycle 25 homolog A (S. pombe) ENSG00000164045 HU-07288-1 CDC25B cell division cycle 25 homolog B (S. pombe) ENSG00000101224 HU-06033-1 CDKN3 cyclin-dependent kinase inhibitor 3 ENSG00000100526 HU-02274-1 CTDSP1 CTD (carboxy-terminal domain,
    [Show full text]
  • PTPRG Suppresses Tumor Growth and Invasion Via Inhibition of Akt Signaling in Nasopharyngeal Carcinoma
    www.impactjournals.com/oncotarget/ Oncotarget, Vol. 6, No. 15 PTPRG suppresses tumor growth and invasion via inhibition of Akt signaling in nasopharyngeal carcinoma Arthur Kwok Leung Cheung1,2, Joseph Chok Yan Ip1, Adrian Chi Hang Chu1, Yue Cheng1,2, Merrin Man Long Leong1, Josephine Mun Yee Ko1, Wai Ho Shuen1,4, Hong Lok Lung1,2 and Maria Li Lung1,2,3 1 Department of Clinical Oncology, University of Hong Kong, Hong Kong (SAR), People’s Republic of China 2 Centre for Cancer Research, University of Hong Kong, Hong Kong (SAR), People’s Republic of China 3 Centre for Nasopharyngeal Carcinoma Research, University of Hong Kong, Hong Kong (SAR), People’s Republic of China 4 Division of Medical Oncology, National Cancer Centre, Singapore Correspondence to: Maria Li Lung, email: [email protected] Keywords: PTPRG, Akt, EGFR, nasopharyngeal carcinoma, tumor suppressor Received: January 13, 2015 Accepted: April 03, 2015 Published: April 19, 2015 This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. ABSTRACT Protein Tyrosine Phosphatase, Receptor Type G (PTPRG) was identified as a candidate tumor suppressor gene in nasopharyngeal carcinoma (NPC). PTPRG induces significantin vivo tumor suppression in NPC. We identified EGFR as a PTPRG potential interacting partner and examined this interaction. Dephosphorylation of EGFR at EGFR-Y1068 and -Y1086 sites inactivated the PI3K/Akt signaling cascade and subsequent down-regulation of downstream pro-angiogenic and -invasive proteins (VEGF, IL6, and IL8) and suppressed tumor cell proliferation, angiogenesis, and invasion.
    [Show full text]