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Perampalam P, MacDonald JI, Zakirova K, Passos DT, Wasif S, Ramos-Valdes Y, Hervieu M, Mehlen P, Rottapel R, Gibert B, Correa RJM, Shepherd TG, Dick FA. Netrin signaling mediates survival of dormant epithelial ovarian cancer cells. eLife 2024; 12:RP91766. [PMID: 39023520 PMCID: PMC11257678 DOI: 10.7554/elife.91766] [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] [Indexed: 07/20/2024] Open
Abstract
Dormancy in cancer is a clinical state in which residual disease remains undetectable for a prolonged duration. At a cellular level, rare cancer cells cease proliferation and survive chemotherapy and disseminate disease. We created a suspension culture model of high-grade serous ovarian cancer (HGSOC) dormancy and devised a novel CRISPR screening approach to identify survival genes in this context. In combination with RNA-seq, we discovered the Netrin signaling pathway as critical to dormant HGSOC cell survival. We demonstrate that Netrin-1, -3, and its receptors are essential for low level ERK activation to promote survival, and that Netrin activation of ERK is unable to induce proliferation. Deletion of all UNC5 family receptors blocks Netrin signaling in HGSOC cells and compromises viability during the dormancy step of dissemination in xenograft assays. Furthermore, we demonstrate that Netrin-1 and -3 overexpression in HGSOC correlates with poor outcome. Specifically, our experiments reveal that Netrin overexpression elevates cell survival in dormant culture conditions and contributes to greater spread of disease in a xenograft model of abdominal dissemination. This study highlights Netrin signaling as a key mediator HGSOC cancer cell dormancy and metastasis.
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Affiliation(s)
- Pirunthan Perampalam
- London Regional Cancer Program, London Health Sciences Centre Research InstituteLondonCanada
- Department of Biochemistry, University of Western OntarioLondonCanada
| | - James I MacDonald
- London Regional Cancer Program, London Health Sciences Centre Research InstituteLondonCanada
- Department of Pathology and Laboratory Medicine, University of Western OntarioLondonCanada
| | - Komila Zakirova
- London Regional Cancer Program, London Health Sciences Centre Research InstituteLondonCanada
- Department of Pathology and Laboratory Medicine, University of Western OntarioLondonCanada
| | - Daniel T Passos
- London Regional Cancer Program, London Health Sciences Centre Research InstituteLondonCanada
- Department of Pathology and Laboratory Medicine, University of Western OntarioLondonCanada
| | - Sumaiyah Wasif
- London Regional Cancer Program, London Health Sciences Centre Research InstituteLondonCanada
- Department of Pathology and Laboratory Medicine, University of Western OntarioLondonCanada
| | - Yudith Ramos-Valdes
- London Regional Cancer Program, London Health Sciences Centre Research InstituteLondonCanada
- The Mary and John Knight Translational Ovarian Cancer Research Unit, London Regional Cancer ProgramLondonCanada
| | - Maeva Hervieu
- Apoptosis, Cancer and Development Laboratory - Equipe labellisée ‘La Ligue’, LabEx DEVweCAN, Institut Convergence PLAsCAN, Centre de Recherche en Cancérologie de Lyon (CRCL), INSERM U1052-CNRS UMR5286, Université de Lyon, Université Claude Bernard Lyon1, Centre Léon BérardLyonFrance
| | - Patrick Mehlen
- Apoptosis, Cancer and Development Laboratory - Equipe labellisée ‘La Ligue’, LabEx DEVweCAN, Institut Convergence PLAsCAN, Centre de Recherche en Cancérologie de Lyon (CRCL), INSERM U1052-CNRS UMR5286, Université de Lyon, Université Claude Bernard Lyon1, Centre Léon BérardLyonFrance
- Netris PharmaLyonFrance
| | - Rob Rottapel
- Princess Margaret Cancer Centre, University Health NetworkTorontoCanada
- Department of Medical Biophysics, University of Toronto, 1 King’s College CircleTorontoCanada
| | - Benjamin Gibert
- Apoptosis, Cancer and Development Laboratory - Equipe labellisée ‘La Ligue’, LabEx DEVweCAN, Institut Convergence PLAsCAN, Centre de Recherche en Cancérologie de Lyon (CRCL), INSERM U1052-CNRS UMR5286, Université de Lyon, Université Claude Bernard Lyon1, Centre Léon BérardLyonFrance
| | - Rohann JM Correa
- London Regional Cancer Program, London Health Sciences Centre Research InstituteLondonCanada
- Department of Oncology, Western UniversityLondonCanada
| | - Trevor G Shepherd
- London Regional Cancer Program, London Health Sciences Centre Research InstituteLondonCanada
- The Mary and John Knight Translational Ovarian Cancer Research Unit, London Regional Cancer ProgramLondonCanada
- Department of Oncology, Western UniversityLondonCanada
- Department of Obstetrics and Gynecology, Western UniversityLondonCanada
- Department of Anatomy and Cell Biology, Western UniversityLondonCanada
| | - Frederick A Dick
- London Regional Cancer Program, London Health Sciences Centre Research InstituteLondonCanada
- Department of Pathology and Laboratory Medicine, University of Western OntarioLondonCanada
- Department of Oncology, Western UniversityLondonCanada
- Children's Health Research InstituteLondonCanada
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2
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Drastichova Z, Trubacova R, Novotny J. Regulation of phosphosignaling pathways involved in transcription of cell cycle target genes by TRH receptor activation in GH1 cells. Biomed Pharmacother 2023; 168:115830. [PMID: 37931515 DOI: 10.1016/j.biopha.2023.115830] [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: 08/29/2023] [Revised: 10/30/2023] [Accepted: 10/31/2023] [Indexed: 11/08/2023] Open
Abstract
Thyrotropin-releasing hormone (TRH) is known to activate several cellular signaling pathway, but the activation of the TRH receptor (TRH-R) has not been reported to regulate gene transcription. The aim of this study was to identify phosphosignaling pathways and phosphoprotein complexes associated with gene transcription in GH1 pituitary cells treated with TRH or its analog, taltirelin (TAL), using label-free bottom-up mass spectrometry-based proteomics. Our detailed analysis provided insight into the mechanism through which TRH-R activation may regulate the transcription of genes related to the cell cycle and proliferation. It involves control of the signaling pathways for β-catenin/Tcf, Notch/RBPJ, p53/p21/Rbl2/E2F, Myc, and YY1/Rb1/E2F through phosphorylation and dephosphorylation of their key components. In many instances, the phosphorylation patterns of differentially phosphorylated phosphoproteins in TRH- or TAL-treated cells were identical or displayed a similar trend in phosphorylation. However, some phosphoproteins, especially components of the Wnt/β-catenin/Tcf and YY1/Rb1/E2F pathways, exhibited different phosphorylation patterns in TRH- and TAL-treated cells. This supports the notion that TRH and TAL may act, at least in part, as biased agonists. Additionally, the deficiency of β-arrestin2 resulted in a reduced number of alterations in phosphorylation, highlighting the critical role of β-arrestin2 in the signal transduction from TRH-R in the plasma membrane to transcription factors in the nucleus.
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Affiliation(s)
- Zdenka Drastichova
- Department of Physiology, Faculty of Science, Charles University, 128 00 Prague, Czechia
| | - Radka Trubacova
- Department of Physiology, Faculty of Science, Charles University, 128 00 Prague, Czechia; Institute of Physiology, Czech Academy of Sciences, 142 20 Prague, Czechia
| | - Jiri Novotny
- Department of Physiology, Faculty of Science, Charles University, 128 00 Prague, Czechia.
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3
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Gala HP, Saha D, Venugopal N, Aloysius A, Purohit G, Dhawan J. A transcriptionally repressed quiescence program is associated with paused RNAPII and is poised for cell cycle reentry. J Cell Sci 2022; 135:275901. [PMID: 35781573 DOI: 10.1242/jcs.259789] [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] [Received: 01/20/2022] [Accepted: 06/27/2022] [Indexed: 11/20/2022] Open
Abstract
Adult stem cells persist in mammalian tissues by entering a state of reversible quiescence/ G0, associated with low transcription. Using cultured myoblasts and muscle stem cells, we report that in G0, global RNA content and synthesis are substantially repressed, correlating with decreased RNA Polymerase II (RNAPII) expression and activation. Integrating RNAPII occupancy and transcriptome profiling, we identify repressed networks and a role for promoter-proximal RNAPII pausing in G0. Strikingly, RNAPII shows enhanced pausing in G0 on repressed genes encoding regulators of RNA biogenesis (Nucleolin, Rps24, Ctdp1); release of pausing is associated with their increased expression in G1. Knockdown of these transcripts in proliferating cells leads to induction of G0 markers, confirming the importance of their repression in establishment of G0. A targeted screen of RNAPII regulators revealed that knockdown of Aff4 (positive regulator of elongation) unexpectedly enhances expression of G0-stalled genes and hastens S phase; NELF, a regulator of pausing appears to be dispensable. We propose that RNAPII pausing contributes to transcriptional control of a subset of G0-repressed genes to maintain quiescence and impacts the timing of the G0-G1 transition.
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Affiliation(s)
- Hardik P Gala
- Centre for Cellular and Molecular Biology, Hyderabad, 500007, India.,Institute for Stem Cell Science and Regenerative Medicine, Bangalore, 560065, India
| | - Debarya Saha
- Centre for Cellular and Molecular Biology, Hyderabad, 500007, India
| | - Nisha Venugopal
- Centre for Cellular and Molecular Biology, Hyderabad, 500007, India.,Institute for Stem Cell Science and Regenerative Medicine, Bangalore, 560065, India
| | - Ajoy Aloysius
- Centre for Cellular and Molecular Biology, Hyderabad, 500007, India.,Institute for Stem Cell Science and Regenerative Medicine, Bangalore, 560065, India.,National Center for Biological Sciences, Bangalore, 560065, India
| | - Gunjan Purohit
- Centre for Cellular and Molecular Biology, Hyderabad, 500007, India
| | - Jyotsna Dhawan
- Centre for Cellular and Molecular Biology, Hyderabad, 500007, India.,Institute for Stem Cell Science and Regenerative Medicine, Bangalore, 560065, India
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4
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Retzbach EP, Sheehan SA, Krishnan H, Zheng H, Zhao C, Goldberg GS. Independent effects of Src kinase and podoplanin on anchorage independent cell growth and migration. Mol Carcinog 2022; 61:677-689. [PMID: 35472679 PMCID: PMC9233000 DOI: 10.1002/mc.23410] [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: 11/07/2021] [Revised: 01/19/2022] [Accepted: 01/27/2022] [Indexed: 11/07/2022]
Abstract
The Src tyrosine kinase is a strong tumor promotor. Over a century of research has elucidated fundamental mechanisms that drive its oncogenic potential. Src phosphorylates effector proteins to promote hallmarks of tumor progression. For example, Src associates with the Cas focal adhesion adaptor protein to promote anchorage independent cell growth. In addition, Src phosphorylates Cas to induce Pdpn expression to promote cell migration. Pdpn is a transmembrane receptor that can independently increase cell migration in the absence of oncogenic Src kinase activity. However, to our knowledge, effects of Src kinase activity on anchorage independent cell growth and migration have not been examined in the absence of Pdpn expression. Here, we analyzed the effects of an inducible Src kinase construct in knockout cells with and without exogenous Pdpn expression on cell morphology migration and anchorage independent growth. We report that Src promoted anchorage independent cell growth in the absence of Pdpn expression. In contrast, Src was not able to promote cell migration in the absence of Pdpn expression. In addition, continued Src kinase activity was required for cells to assume a transformed morphology since cells reverted to a nontransformed morphology upon cessation of Src kinase activity. We also used phosphoproteomic analysis to identify 28 proteins that are phosphorylated in Src transformed cells in a Pdpn dependent manner. Taken together, these data indicate that Src utilizes Pdpn to promote transformed cell growth and motility in complementary, but parallel, as opposed to serial, pathways.
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Affiliation(s)
- Edward P. Retzbach
- Department of Molecular Biology, And Graduate School of Biomedical Sciences, School of Osteopathic Medicine, Rowan University, Stratford, NJ, 08084, USA
| | - Stephanie A. Sheehan
- Department of Molecular Biology, And Graduate School of Biomedical Sciences, School of Osteopathic Medicine, Rowan University, Stratford, NJ, 08084, USA
| | - Harini Krishnan
- Department of Physiology and Biophysics, School of Medicine, Stony Brook University Stony Brook, NY, 11794-8661, USA
| | - Haiyan Zheng
- Biological Mass Spectrometry Resources, Robert Wood Johnson Medical School, Rutgers, State University of New jersey, New Brunswick, NJ, 08901, USA
| | - Caifeng Zhao
- Biological Mass Spectrometry Resources, Robert Wood Johnson Medical School, Rutgers, State University of New jersey, New Brunswick, NJ, 08901, USA
| | - Gary S. Goldberg
- Department of Molecular Biology, And Graduate School of Biomedical Sciences, School of Osteopathic Medicine, Rowan University, Stratford, NJ, 08084, USA
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5
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Abstract
Perfectly orchestrated periodic gene expression during cell cycle progression is essential for maintaining genome integrity and ensuring that cell proliferation can be stopped by environmental signals. Genetic and proteomic studies during the past two decades revealed remarkable evolutionary conservation of the key mechanisms that control cell cycle-regulated gene expression, including multisubunit DNA-binding DREAM complexes. DREAM complexes containing a retinoblastoma family member, an E2F transcription factor and its dimerization partner, and five proteins related to products of Caenorhabditis elegans multivulva (Muv) class B genes lin-9, lin-37, lin-52, lin-53, and lin-54 (comprising the MuvB core) have been described in diverse organisms, from worms to humans. This review summarizes the current knowledge of the structure, function, and regulation of DREAM complexes in different organisms, as well as the role of DREAM in human disease. Expected final online publication date for the Annual Review of Genetics, Volume 55 is November 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- Hayley Walston
- Department of Human and Molecular Genetics, Virginia Commonwealth University, Richmond, Virginia 23298, USA;
| | - Audra N Iness
- School of Medicine, Virginia Commonwealth University, Richmond, Virginia 23298, USA
| | - Larisa Litovchick
- Department of Human and Molecular Genetics, Virginia Commonwealth University, Richmond, Virginia 23298, USA; .,Division of Hematology, Oncology and Palliative Care, Department of Internal Medicine, Virginia Commonwealth University, Richmond, Virginia 23298, USA.,Massey Cancer Center, Richmond, Virginia 23298, USA
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6
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Ventura E, Pentimalli F, Giordano A. RBL2/p130: a direct AKT substrate and mediator of AKT inhibition-induced apoptosis. Oncoscience 2018; 5:278-280. [PMID: 30652113 PMCID: PMC6326738 DOI: 10.18632/oncoscience.467] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2018] [Accepted: 07/09/2018] [Indexed: 12/12/2022] Open
Affiliation(s)
- Elisa Ventura
- Sbarro Institute for Cancer Research and Molecular Medicine, Center for Biotechnology, College of Science and Technology, Temple University, Philadelphia, PA 19122, USA; Department of Medicine, Surgery and Neuroscience, University of Siena, 53100, Siena, Italy
| | - Francesca Pentimalli
- Sbarro Institute for Cancer Research and Molecular Medicine, Center for Biotechnology, College of Science and Technology, Temple University, Philadelphia, PA 19122, USA; Department of Medicine, Surgery and Neuroscience, University of Siena, 53100, Siena, Italy
| | - Antonio Giordano
- Sbarro Institute for Cancer Research and Molecular Medicine, Center for Biotechnology, College of Science and Technology, Temple University, Philadelphia, PA 19122, USA; Department of Medicine, Surgery and Neuroscience, University of Siena, 53100, Siena, Italy
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7
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The Temporal Regulation of S Phase Proteins During G 1. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2018; 1042:335-369. [PMID: 29357066 DOI: 10.1007/978-981-10-6955-0_16] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Successful DNA replication requires intimate coordination with cell-cycle progression. Prior to DNA replication initiation in S phase, a series of essential preparatory events in G1 phase ensures timely, complete, and precise genome duplication. Among the essential molecular processes are regulated transcriptional upregulation of genes that encode replication proteins, appropriate post-transcriptional control of replication factor abundance and activity, and assembly of DNA-loaded protein complexes to license replication origins. In this chapter we describe these critical G1 events necessary for DNA replication and their regulation in the context of both cell-cycle entry and cell-cycle progression.
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8
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Pentimalli F, Forte IM, Esposito L, Indovina P, Iannuzzi CA, Alfano L, Costa C, Barone D, Rocco G, Giordano A. RBL2/p130 is a direct AKT target and is required to induce apoptosis upon AKT inhibition in lung cancer and mesothelioma cell lines. Oncogene 2018; 37:3657-3671. [PMID: 29606701 DOI: 10.1038/s41388-018-0214-3] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Revised: 12/30/2017] [Accepted: 02/03/2018] [Indexed: 12/29/2022]
Abstract
The retinoblastoma (RB) protein family includes RB1/p105, RBL1/p107, and RBL2/p130, which are key factors in cell-cycle regulation and stand at the crossroads of multiple pathways dictating cell fate decisions. The role of RB proteins in apoptosis is controversial because they can inhibit or promote apoptosis depending on the context, on the apoptotic stimuli and on their intrinsic status, impacting on the response to antitumoral treatments. Here we identified RBL2/p130 as a direct substrate of the AKT kinase, a key antiapoptotic factor hyperactive in multiple cancer types. We showed that RBL2/p130 and AKT1 physically interact and AKT phosphorylates RBL2/p130 Ser941, located in the pocket domain, but not when this residue is mutated into Ala. We found that pharmacological inhibition of AKT, through the highly selective AKT inhibitor VIII (AKTiVIII), impairs RBL2/p130 Ser941 phosphorylation and increases RBL2/p130 stability, mRNA expression and nuclear levels in both lung cancer and mesothelioma cell lines, mirroring the more extensively studied effects on the p27 cell-cycle inhibitor. Consistently, AKT inhibition reduced cell viability, induced cell accumulation in G0/G1, and triggered apoptosis, which proved to be largely dependent on RBL2/p130 itself, as shown upon RBL2/p130 silencing. AKT inhibition induced RBL2/p130-dependent apoptosis also in HEK-293 cells, in which re-expression of a short hairpin-resistant RBL2/p130 was able to rescue AKTiVIII-induced apoptosis upon RBL2/p130 silencing. Our data also showed that the combination of AKT and cyclin-dependent kinases (CDK) inhibitors, which converge on the re-activation of RBL2/p130 antitumoral potential, could be a promising anticancer strategy.
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Affiliation(s)
- Francesca Pentimalli
- Oncology Research Center of Mercogliano (CROM), Istituto Nazionale Tumori - IRCCS, "Fondazione G. Pascale", 80131, Napoli, Italy.
| | - Iris M Forte
- Oncology Research Center of Mercogliano (CROM), Istituto Nazionale Tumori - IRCCS, "Fondazione G. Pascale", 80131, Napoli, Italy
| | - Luca Esposito
- Oncology Research Center of Mercogliano (CROM), Istituto Nazionale Tumori - IRCCS, "Fondazione G. Pascale", 80131, Napoli, Italy
| | - Paola Indovina
- Sbarro Institute for Cancer Research and Molecular Medicine, Center for Biotechnology, College of Scienceand Technology, Temple University, Philadelphia, PA, 19122, USA
| | - Carmelina A Iannuzzi
- Oncology Research Center of Mercogliano (CROM), Istituto Nazionale Tumori - IRCCS, "Fondazione G. Pascale", 80131, Napoli, Italy.,Department of Medicine, Surgery and Neuroscience, University of Siena, 53100, Siena, Italy
| | - Luigi Alfano
- Oncology Research Center of Mercogliano (CROM), Istituto Nazionale Tumori - IRCCS, "Fondazione G. Pascale", 80131, Napoli, Italy
| | - Caterina Costa
- Oncology Research Center of Mercogliano (CROM), Istituto Nazionale Tumori - IRCCS, "Fondazione G. Pascale", 80131, Napoli, Italy
| | - Daniela Barone
- Oncology Research Center of Mercogliano (CROM), Istituto Nazionale Tumori - IRCCS, "Fondazione G. Pascale", 80131, Napoli, Italy.,Department of Medicine, Surgery and Neuroscience, University of Siena, 53100, Siena, Italy
| | - Gaetano Rocco
- Division of Thoracic Surgery, Department of Thoracic Surgery and Oncology, Istituto Nazionale Tumori "Fondazione G. Pascale"; IRCCS, 80131, Napoli, Italy
| | - Antonio Giordano
- Sbarro Institute for Cancer Research and Molecular Medicine, Center for Biotechnology, College of Scienceand Technology, Temple University, Philadelphia, PA, 19122, USA. .,Department of Medicine, Surgery and Neuroscience, University of Siena, 53100, Siena, Italy.
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9
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Hacker B, Schultheiß C, Döring M, Kurzik-Dumke U. Molecular partners of hNOT/ALG3, the human counterpart of the Drosophila NOT and yeast ALG3 gene, suggest its involvement in distinct cellular processes relevant to congenital disorders of glycosylation, cancer, neurodegeneration and a variety of further pathologies. Hum Mol Genet 2018; 27:1858-1878. [DOI: 10.1093/hmg/ddy087] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2018] [Accepted: 03/06/2018] [Indexed: 01/04/2023] Open
Affiliation(s)
- Benedikt Hacker
- Laboratory for Comparative Tumour Biology, Institute of Medical Microbiology and Hygiene, University Medical Centre, Johannes Gutenberg University, 55131 Mainz, Germany
| | - Christoph Schultheiß
- Laboratory for Comparative Tumour Biology, Institute of Medical Microbiology and Hygiene, University Medical Centre, Johannes Gutenberg University, 55131 Mainz, Germany
| | - Michael Döring
- Laboratory for Comparative Tumour Biology, Institute of Medical Microbiology and Hygiene, University Medical Centre, Johannes Gutenberg University, 55131 Mainz, Germany
| | - Ursula Kurzik-Dumke
- Laboratory for Comparative Tumour Biology, Institute of Medical Microbiology and Hygiene, University Medical Centre, Johannes Gutenberg University, 55131 Mainz, Germany
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10
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Medunjanin S, Schleithoff L, Fiegehenn C, Weinert S, Zuschratter W, Braun-Dullaeus RC. GSK-3β controls NF-kappaB activity via IKKγ/NEMO. Sci Rep 2016; 6:38553. [PMID: 27929056 PMCID: PMC5144080 DOI: 10.1038/srep38553] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2016] [Accepted: 11/09/2016] [Indexed: 12/24/2022] Open
Abstract
The NF-κB signaling pathway is central for the innate immune response and its deregulation is found in multiple disorders such as autoimmune, chronic inflammatory and metabolic diseases. IKKγ/NEMO is essential for NF-κB activation and NEMO dysfunction in humans has been linked to so-called progeria syndromes, which are characterized by advanced ageing due to age-dependent inflammatory diseases. It has been suggested that glycogen synthase kinase-3β (GSK-3β) participates in NF-κB regulation but the exact mechanism remained incompletely understood. In this study, we identified NEMO as a GSK-3β substrate that is phosphorylated at serine 8, 17, 31 and 43 located within its N-terminal domain. The kinase forms a complex with wild-type NEMO while point mutations of NEMO at the specific serines abrogated GSK-3β binding and subsequent phosphorylation of NEMO resulting in its destabilization. However, K63-linked polyubiquitination was augmented in mutated NEMO explaining an increased binding to IKKα and IKKβ. Even IκBα was found degraded. Still, TNFα-stimulated NF-κB activation was impaired pointing towards an un-controlled signalling process. Our data suggest that GSK-3β is critically important for ordered NF-κB signalling through modulation of NEMO phosphorylation.
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Affiliation(s)
- Senad Medunjanin
- Internal Medicine/Cardiology and Angiology, Magdeburg University, Magdeburg, Germany
| | - Lisa Schleithoff
- Internal Medicine/Cardiology and Angiology, Magdeburg University, Magdeburg, Germany
| | - Christian Fiegehenn
- Internal Medicine/Cardiology and Angiology, Magdeburg University, Magdeburg, Germany
| | - Soenke Weinert
- Internal Medicine/Cardiology and Angiology, Magdeburg University, Magdeburg, Germany
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11
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Rashid NN, Rothan HA, Yusoff MSM. The association of mammalian DREAM complex and HPV16 E7 proteins. Am J Cancer Res 2015; 5:3525-3533. [PMID: 26885443 PMCID: PMC4731628] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2015] [Accepted: 11/12/2015] [Indexed: 06/05/2023] Open
Abstract
The mammalian DREAM (Drosophila, RB, E2F, and Myb) complex was discovered in 2004 by several research groups. It was initially identified in Drosophila followed by Caenorhaditis elegans and later in mammalian cells. The composition of DREAM is temporally regulated during cell cycle; being associated with E2F-4 and either p107 or p130 in G0/G1 (repressive DREAM complexes) and with B-myb transcription factor in S/G2 (activator DREAM complex). High risk human papillomavirus (HPV) E6 and E7 oncoproteins expression are important for malignant transformation of cervical cancer cells. In particular, the E7 of high risk HPV binds to pRB family members (pRB, p107 and p130) for degradation. It has recently been discovered that the p107 and p130 'pocket proteins' are members of mammalian DREAM complexes. With this understanding, we would like to hypothesise the mammalian DREAM complex could plays a critical role for malignant transformation in cervical cancer cells.
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Affiliation(s)
- Nurshamimi Nor Rashid
- Department of Molecular Medicine, Faculty of Medicine, University of Malaya Kuala Lumpur, Malaysia
| | - Hussin A Rothan
- Department of Molecular Medicine, Faculty of Medicine, University of Malaya Kuala Lumpur, Malaysia
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12
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Weathington NM, Snavely CA, Chen BB, Zhao J, Zhao Y, Mallampalli RK. Glycogen synthase kinase-3β stabilizes the interleukin (IL)-22 receptor from proteasomal degradation in murine lung epithelia. J Biol Chem 2014; 289:17610-9. [PMID: 24742671 DOI: 10.1074/jbc.m114.551747] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Signaling through the interleukin (IL)-22 cytokine axis provides essential immune protection in the setting of extracellular infection as part of type 17 immunity. Molecular regulation of IL-22 receptor (IL-22R) protein levels is unknown. In murine lung epithelia, IL-22R is a relatively short-lived protein (t½ ∼1.5 h) degraded by the ubiquitin proteasome under normal unstimulated conditions, but its degradation is accelerated by IL-22 treatment. Lys(449) within the intracellular C-terminal domain of the IL-22R serves as a ubiquitin acceptor site as disruption of this site by deletion or site-directed mutagenesis creates an IL-22R variant that, when expressed in cells, is degradation-resistant and not ubiquitinated. Glycogen synthase kinase (GSK)-3β phosphorylates the IL-22R within a consensus phosphorylation signature at Ser(410) and Ser(414), and IL-22 treatment of cells triggers GSK-3β inactivation. GSK-3β overexpression results in accumulation of IL-22R protein, whereas GSK-3β depletion in cells reduces levels of the receptor. Mutagenesis of IL-22R at Ser(410) and Ser(414) results in receptor variants that display reduced phosphorylation levels and are more labile as compared with wild-type IL-22R when expressed in cells. Further, the cytoskeletal protein cortactin, which is important for epithelial spreading and barrier formation, is phosphorylated and activated at the epithelial cell leading edge after treatment with IL-22, but this effect is reduced after GSK-3β knockdown. These findings reveal the ability of GSK-3β to modulate IL-22R protein stability that might have significant implications for cytoprotective functions and therapeutic targeting of the IL-22 signaling axis.
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Affiliation(s)
| | - Courtney A Snavely
- From the Department of Medicine, the Acute Lung Injury Center of Excellence, and
| | - Bill B Chen
- From the Department of Medicine, the Acute Lung Injury Center of Excellence, and
| | - Jing Zhao
- From the Department of Medicine, the Acute Lung Injury Center of Excellence, and
| | - Yutong Zhao
- From the Department of Medicine, the Acute Lung Injury Center of Excellence, and the Department of Cell Biology and Physiology, University of Pittsburgh, Pittsburgh, Pennsylvania 15213 and
| | - Rama K Mallampalli
- From the Department of Medicine, the Acute Lung Injury Center of Excellence, and the Department of Cell Biology and Physiology, University of Pittsburgh, Pittsburgh, Pennsylvania 15213 and the Medical Specialty Service Line, Veterans Affairs Pittsburgh Healthcare System, Pittsburgh, Pennsylvania 15240
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13
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Abstract
INTRODUCTION Myelomeningocele is one of the major congenital malformations involving the central nervous system. It is caused by a disruption of the neural tube closure, which is completed at 3-4 weeks of gestation. DISCUSSION Multidisciplinary approach is necessary to treat and support this malformation which is a huge burden to the patient, family, and the society. This is a characteristic anomaly that it is known that taking folic acid during the periconceptional period, it is possible to reduce the risk of having a neural tube defect (NTD). Although folate fortification had dramatically reduced the incidence, it was not possible to diminish the risk. To date, many studies have been conducted focusing on candidate genes related to folate and glucose metabolism. We will describe a brief review of genetic etiology of candidate genes of metabolic pathways of folate and glucose, animal models of NTDs, and finally recent studies of microRNA.
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14
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Okamura K, Miki D, Nohara K. Inorganic arsenic exposure induces E2F-dependent G0/G1 arrest via an increase in retinoblastoma family protein p130 in B-cell lymphoma A20 cells. Genes Cells 2013; 18:839-49. [PMID: 23890198 DOI: 10.1111/gtc.12079] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2013] [Accepted: 05/27/2013] [Indexed: 11/29/2022]
Abstract
Inorganic arsenic exerts toxic effect on multiple systems including the immune system. We previously showed in a study on mouse thymocytes and B-cell lymphoma A20 cells that arsenite induces cell cycle arrest at G0/G1 by suppressing expression of E2F-target genes. In this study, we furthermore investigated the involvement of retinoblastoma (RB) family proteins in E2F-dependent cell cycle arrest by arsenite. Arsenite exposure of A20 cells was showed to increase the protein level of p130, a RB family member, without changing the mRNA level. Suppression of arsenite-induced p130 by siRNA reduced the G0/G1 phase, indicating that p130 accumulation is responsible for arsenite-induced G0/G1 arrest. The accumulated p130 was shown to increase the p130 complex with E2F4, a transcription-suppressing E2F. Comparison by Western blotting of arsenite-induced p130 and p130 accumulated by a proteasome inhibitor suggested that arsenite-induced p130 is hypophosphorylated and hypoubiquitinated and refractory to proteasome-dependent degradation. We also showed that arsenite increases mRNA and protein of p16(INK4a), an inhibitor of CDK4/6 that phosphorylates p130. Down-regulation of arsenite-induced p16(INK4a) by siRNA suppressed the p130 accumulation. We propose a novel mechanism in which arsenite inhibits phosphorylation/ubiquitin-dependent proteasome degradation of p130 by inducing p16(INK4a) and the accumulated p130 causes cell cycle arrest with E2F4.
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Affiliation(s)
- Kazuyuki Okamura
- Center for Environmental Health Sciences, National Institute for Environmental Studies, Tsukuba, 305-8506, Japan; Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, 305-8577, Japan
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15
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Saeed M, Schwarze F, Loidl A, Meraner J, Lechner M, Loidl P. In vitro phosphorylation and acetylation of the murine pocket protein Rb2/p130. PLoS One 2012; 7:e46174. [PMID: 23029429 PMCID: PMC3454344 DOI: 10.1371/journal.pone.0046174] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2012] [Accepted: 08/30/2012] [Indexed: 12/04/2022] Open
Abstract
The retinoblastoma protein (pRb) and the related proteins Rb2/p130 and 107 represent the “pocket protein” family of cell cycle regulators. A key function of these proteins is the cell cycle dependent modulation of E2F-regulated genes. The biological activity of these proteins is controlled by acetylation and phosphorylation in a cell cycle dependent manner. In this study we attempted to investigate the interdependence of acetylation and phosphorylation of Rb2/p130 in vitro. After having identified the acetyltransferase p300 among several acetyltransferases to be associated with Rb2/p130 during S-phase in NIH3T3 cells in vivo, we used this enzyme and the CDK4 protein kinase for in vitro modification of a variety of full length Rb2/p130 and truncated versions with mutations in the acetylatable lysine residues 1079, 128 and 130. Mutation of these residues results in the complete loss of Rb2/p130 acetylation. Replacement of lysines by arginines strongly inhibits phosphorylation of Rb2/p130 by CDK4; the inhibitory effect of replacement by glutamines is less pronounced. Preacetylation of Rb2/p130 strongly enhances CDK4-catalyzed phosphorylation, whereas deacetylation completely abolishes in vitro phosphorylation. In contrast, phosphorylation completely inhibits acetylation of Rb2/p130 by p300. These results suggest a mutual interdependence of modifications in a way that acetylation primes Rb2/p130 for phosphorylation and only dephosphorylated Rb2/p130 can be subject to acetylation. Human papillomavirus 16-E7 protein, which increases acetylation of Rb2/p130 by p300 strongly reduces phosphorylation of this protein by CDK4. This suggests that the balance between phosphorylation and acetylation of Rb2/p130 is essential for its biological function in cell cycle control.
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Affiliation(s)
- Muhammad Saeed
- Division of Molecular Biology, Biocenter, Innsbruck Medical University, Innsbruck, Austria
| | - Florian Schwarze
- Division of Molecular Biology, Biocenter, Innsbruck Medical University, Innsbruck, Austria
| | - Adele Loidl
- Division of Molecular Biology, Biocenter, Innsbruck Medical University, Innsbruck, Austria
| | - Joachim Meraner
- Division of Molecular Biology, Biocenter, Innsbruck Medical University, Innsbruck, Austria
| | - Markus Lechner
- Division of Molecular Biology, Biocenter, Innsbruck Medical University, Innsbruck, Austria
| | - Peter Loidl
- Division of Molecular Biology, Biocenter, Innsbruck Medical University, Innsbruck, Austria
- * E-mail:
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16
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The MuvB complex sequentially recruits B-Myb and FoxM1 to promote mitotic gene expression. Genes Dev 2012; 26:474-89. [PMID: 22391450 DOI: 10.1101/gad.181933.111] [Citation(s) in RCA: 236] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Cell cycle progression is dependent on two major waves of gene expression. Early cell cycle gene expression occurs during G1/S to generate factors required for DNA replication, while late cell cycle gene expression begins during G2 to prepare for mitosis. Here we demonstrate that the MuvB complex-comprised of LIN9, LIN37, LIN52, LIN54, and RBBP4-serves an essential role in three distinct transcription complexes to regulate cell cycle gene expression. The MuvB complex, together with the Rb-like protein p130, E2F4, and DP1, forms the DREAM complex during quiescence and represses expression of both early and late genes. Upon cell cycle entry, the MuvB complex dissociates from p130/DREAM, binds to B-Myb, and reassociates with the promoters of late genes during S phase. MuvB and B-Myb are required for the subsequent recruitment of FoxM1 to late gene promoters during G2. The MuvB complex remains bound to FoxM1 during peak late cell cycle gene expression, while B-Myb binding is lost when it undergoes phosphorylation-dependent, proteasome-mediated degradation during late S phase. Our results reveal a novel role for the MuvB complex in recruiting B-Myb and FoxM1 to promote late cell cycle gene expression and in regulating cell cycle gene expression from quiescence through mitosis.
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17
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The retinoblastoma family of proteins and their regulatory functions in the mammalian cell division cycle. Cell Div 2012; 7:10. [PMID: 22417103 PMCID: PMC3325851 DOI: 10.1186/1747-1028-7-10] [Citation(s) in RCA: 183] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2012] [Accepted: 03/14/2012] [Indexed: 12/15/2022] Open
Abstract
The retinoblastoma (RB) family of proteins are found in organisms as distantly related as humans, plants, and insects. These proteins play a key role in regulating advancement of the cell division cycle from the G1 to S-phases. This is achieved through negative regulation of two important positive regulators of cell cycle entry, E2F transcription factors and cyclin dependent kinases. In growth arrested cells transcriptional activity by E2Fs is repressed by RB proteins. Stimulation of cell cycle entry by growth factor signaling leads to activation of cyclin dependent kinases. They in turn phosphorylate and inactivate the RB family proteins, leading to E2F activation and additional cyclin dependent kinase activity. This propels the cell cycle irreversibly forward leading to DNA synthesis. This review will focus on the basic biochemistry and cell biology governing the regulation and activity of mammalian RB family proteins in cell cycle control.
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Kolupaeva V, Janssens V. PP1 and PP2A phosphatases--cooperating partners in modulating retinoblastoma protein activation. FEBS J 2012; 280:627-43. [PMID: 22299668 DOI: 10.1111/j.1742-4658.2012.08511.x] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The retinoblastoma/pocket protein family is one of the master regulators of the eukaryotic cell cycle. It includes the retinoblastoma protein (Rb) and the related p107 and p130 proteins. The importance of the Rb pathway for homeostasis and tumour suppression is evident from the fact that inactivating mutations in Rb are frequently associated with many cancers. Rbs regulate the cell cycle by controlling the activity of the E2F family of transcription factors. The activity of Rb proteins themselves is modulated by their phosphorylation status at several Ser/Thr residues: phosphorylation by cyclin-dependent kinases inactivates Rb proteins and positively influences the transcription of genes necessary for cell cycle progression. Although the mechanisms of cyclin-dependent kinase-mediated inactivation of Rb proteins are understood in great detail, our knowledge of the process that counteracts Rb phosphorylation is still quite limited. The present review focuses on the Ser/Thr phosphatases that are responsible for the dephosphorylation and thus activation of Rb proteins. Two major scenarios are considered: (a) when pocket proteins are dephosphorylated during regular cell cycle progression and (b) when rapid dephosphorylation is dictated by external stress or growth inhibitory conditions, such as oxidative stress, UV radiation or other DNA-damaging stimuli, and cell differentiation factors. It transpires that protein phosphatase 1 and protein phosphatase 2A can efficiently modulate pocket protein activity in a highly context-dependent manner and both are tightly regulated by the presence of different regulatory subunits or interacting proteins.
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Affiliation(s)
- Victoria Kolupaeva
- Department of Microbiology, New York University School of Medicine, New York, NY 10016, USA.
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19
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Cole AR. GSK3 as a Sensor Determining Cell Fate in the Brain. Front Mol Neurosci 2012; 5:4. [PMID: 22363258 PMCID: PMC3275790 DOI: 10.3389/fnmol.2012.00004] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2011] [Accepted: 01/10/2012] [Indexed: 12/23/2022] Open
Abstract
Glycogen synthase kinase 3 (GSK3) is an unusual serine/threonine kinase that controls many neuronal functions, including neurite outgrowth, synapse formation, neurotransmission, and neurogenesis. It mediates these functions by phosphorylating a wide range of substrates involved in gene transcription, metabolism, apoptosis, cytoskeletal dynamics, signal transduction, lipid membrane dynamics, and trafficking, amongst others. This complicated list of diverse substrates generally follow a more simple pattern: substrates negatively regulated by GSK3-mediated phosphorylation favor a proliferative/survival state, while substrates positively regulated by GSK3 favor a more differentiated/functional state. Accordingly, GSK3 activity is higher in differentiated cells than undifferentiated cells and physiological (Wnt, growth factors) and pharmacological inhibitors of GSK3 promote the proliferative capacity of embryonic stem cells. In the brain, the level of GSK3 activity influences neural progenitor cell proliferation/differentiation in neuroplasticity and repair, as well as efficient neurotransmission in differentiated adult neurons. While defects in GSK3 activity are unlikely to be the primary cause of neurodegenerative diseases, therapeutic regulation of its activity to promote a proliferative/survival versus differentiated/mature functional environment in the brain could be a powerful strategy for treatment of neurodegenerative and other mental disorders.
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Affiliation(s)
- Adam R Cole
- Neurosignalling Group, Garvan Institute of Medical Research Sydney, NSW, Australia
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20
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Kaidanovich-Beilin O, Woodgett JR. GSK-3: Functional Insights from Cell Biology and Animal Models. Front Mol Neurosci 2011; 4:40. [PMID: 22110425 PMCID: PMC3217193 DOI: 10.3389/fnmol.2011.00040] [Citation(s) in RCA: 362] [Impact Index Per Article: 27.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2011] [Accepted: 10/23/2011] [Indexed: 12/13/2022] Open
Abstract
Glycogen synthase kinase-3 (GSK-3) is a widely expressed and highly conserved serine/threonine protein kinase encoded in mammals by two genes that generate two related proteins: GSK-3α and GSK-3β. GSK-3 is active in cells under resting conditions and is primarily regulated through inhibition or diversion of its activity. While GSK-3 is one of the few protein kinases that can be inactivated by phosphorylation, the mechanisms of GSK-3 regulation are more varied and not fully understood. Precise control appears to be achieved by a combination of phosphorylation, localization, and sequestration by a number of GSK-3-binding proteins. GSK-3 lies downstream of several major signaling pathways including the phosphatidylinositol 3′ kinase pathway, the Wnt pathway, Hedgehog signaling and Notch. Specific pools of GSK-3, which differ in intracellular localization, binding partner affinity, and relative amount are differentially sensitized to several distinct signaling pathways and these sequestration mechanisms contribute to pathway insulation and signal specificity. Dysregulation of signaling pathways involving GSK-3 is associated with the pathogenesis of numerous neurological and psychiatric disorders and there are data suggesting GSK-3 isoform-selective roles in several of these. Here, we review the current knowledge of GSK-3 regulation and targets and discuss the various animal models that have been employed to dissect the functions of GSK-3 in brain development and function through the use of conventional or conditional knockout mice as well as transgenic mice. These studies have revealed fundamental roles for these protein kinases in memory, behavior, and neuronal fate determination and provide insights into possible therapeutic interventions.
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Petrov N, Zhidkova O, Serikov V, Zenin V, Popov B. Induction of Wnt/β-catenin signaling in mouse mesenchymal stem cells is associated with activation of the p130 and E2f4 and formation of the p130/Gsk3β/β-catenin complex. Stem Cells Dev 2011; 21:589-97. [PMID: 21631154 DOI: 10.1089/scd.2011.0048] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Proteins p130 and E2f4, members of the retinoblastoma protein (pRb) family/E2F transcription factor family, are the key elements in regulation of cell cycle and differentiation. The functional role of the p130/E2f4 in mesenchymal stem cells (MSC) is unclear. We demonstrate here that activation of the Wnt/β-catenin pathway in mouse MSC is associated with accumulation of active forms of the p130, E2f4, and β-catenin but does not result in inhibition of cell cycle progression. The levels and phosphorylation patterns of p130, E2f4, and β-catenin in MSC do not change during cell cycle progression. This is different from control T98G glyoblastoma cells that accumulated differently phosphorylated forms of the p130 in quiescence, and under active proliferation. In MSC, synchronized at G0/G1 and S cell cycle phases, the p130 and β-catenin physically interact each other, whereas Gsk3β was associated and co-precipitated with both p130 and β-catenin. Our results indicate that Wnt/β-catenin and pRb signal pathways interact with each other and form common p130/Gsk3β/β-catenin complex during MSC cycle progression. Physiological relevance of such complex may be associated with coupling of the cell cycle and differentiation in MSC, which is related to a wide differentiation potential of these stem cells.
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Affiliation(s)
- Nikolay Petrov
- Laboratory of Cell Pathology, Institute of Cytology, Russian Academy of Sciences, St. Petersburg, Russia
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22
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Biggar KK, Storey KB. Perspectives in cell cycle regulation: lessons from an anoxic vertebrate. Curr Genomics 2011; 10:573-84. [PMID: 20514219 PMCID: PMC2817888 DOI: 10.2174/138920209789503905] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2009] [Revised: 08/04/2009] [Accepted: 08/06/2009] [Indexed: 01/07/2023] Open
Abstract
The ability of an animal, normally dependent on aerobic respiration, to suspend breathing and enter an anoxic state for long term survival is clearly a fascinating feat, and has been the focus of numerous biochemical studies. When anoxia tolerant turtles are faced with periods of oxygen deprivation, numerous physiological and biochemical alterations take place in order to facilitate vital reductions in ATP consumption. Such strategies include reversible post-translational modifications as well as the implementation of translation and transcription controls facilitating metabolic depression. Although it is clear that anoxic survival relies on the suppression of ATP consuming processes, the state of the cell cycle in anoxia tolerant vertebrates remain elusive. Several anoxia tolerant invertebrate and embryonic vertebrate models display cell cycle arrest when presented with anoxic stress. Despite this, the cell cycle has not yet been characterized for anoxia tolerant turtles. Understanding how vertebrates respond to anoxia can have important clinical implications. Uncontrollable cellular proliferation and hypoxic tumor progression are inescapably linked in vertebrate tissues. Consequentially, the molecular mechanisms controlling these processes have profound clinical consequences. This review article will discuss the theory of cell cycle arrest in anoxic vertebrates and more specifically, the control of the retinoblastoma pathway, the molecular markers of cell cycle arrest, the activation of checkpoint kinases, and the possibility of translational controls implemented by microRNAs.
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Affiliation(s)
- Kyle K Biggar
- Institute of Biochemistry and Department of Biology, Carleton University, 1125 Colonel By Drive, Ottawa, ON, K1S 5B6, Canada
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23
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Rocha-Sanchez SM, Scheetz LR, Contreras M, Weston MD, Korte M, McGee J, Walsh EJ. Mature mice lacking Rbl2/p130 gene have supernumerary inner ear hair cells and supporting cells. J Neurosci 2011; 31:8883-93. [PMID: 21677172 PMCID: PMC3132102 DOI: 10.1523/jneurosci.5821-10.2011] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2010] [Revised: 04/14/2011] [Accepted: 04/20/2011] [Indexed: 11/21/2022] Open
Abstract
Adult mammalian auditory hair cells (HCs) and their associated supporting cells (SCs) do not proliferate, and HC death leads to irreversible neurosensory hearing loss and balance impairment. In nonmammalian vertebrates, loss of HCs induces mitotic proliferation of adjacent nonsensory SCs and/or direct SC transdifferentiation to generate replacement cells. This results in the structural and functional recovery of the nonmammalian sensory systems. Potential replacement of mammalian auditory HCs, either by transplanting cells or by transforming existing cells through molecular therapy, has long been proposed. However, HC replacement strategies with clear therapeutic potential remain elusive. The retinoblastoma (pRB) family of cell cycle regulators, Rb1, Rbl1 (p107), and Rbl2 (p130), regulate the G(1)- to S-phase transition in proliferating cells. In the inner ear, the biochemical and molecular pathways involving pRBs, particularly p107 and p130, are relatively unexplored and their therapeutic suitability is yet to be determined. In this study, we analyzed the cochleae of adult p130 knock-out (p130(-/-)) mice and showed that lack of the p130 gene results in extra rows of HCs and SCs in the more apical regions of the cochlea. No evidence of transdifferentiation of these supernumerary SCs into HCs was observed in the p130(-/-) mouse. Nevertheless, unscheduled proliferation of SCs in the adult p130(-/-) cochlea coupled to downregulation of bona fide cell cycle inhibitors provides a mechanistic basis for the role of p130 as a regulator of SC and HC mitotic quiescence in the more apical regions of the cochlea. Interestingly, p130(-/-) mice exhibited nearly normal peripheral auditory sensitivity.
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MESH Headings
- Acoustic Stimulation
- Age Factors
- Animals
- Animals, Newborn
- Cell Proliferation
- Ear, Inner/cytology
- Ear, Inner/embryology
- Embryo, Mammalian
- Evoked Potentials, Auditory, Brain Stem/genetics
- Female
- Gene Expression Regulation, Developmental/genetics
- Hair Cells, Auditory, Inner/physiology
- Immunoprecipitation
- Labyrinth Supporting Cells/physiology
- Male
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Myosin VIIa
- Myosins/metabolism
- Otoacoustic Emissions, Spontaneous/genetics
- Receptors, Nerve Growth Factor/metabolism
- Retinoblastoma Protein/deficiency
- SOXB1 Transcription Factors/metabolism
- Tubulin/metabolism
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Affiliation(s)
- Sonia M Rocha-Sanchez
- Department of Oral Biology, Creighton University School of Dentistry, Omaha, Nebraska 68178, USA.
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24
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Cho Y, Kim H, Turner ND, Mann JC, Wei J, Taddeo SS, Davidson LA, Wang N, Vannucci M, Carroll RJ, Chapkin RS, Lupton JR. A chemoprotective fish oil- and pectin-containing diet temporally alters gene expression profiles in exfoliated rat colonocytes throughout oncogenesis. J Nutr 2011; 141:1029-35. [PMID: 21508209 PMCID: PMC3095137 DOI: 10.3945/jn.110.134973] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
We have demonstrated that fish oil- and pectin-containing (FO/P) diets protect against colon cancer compared with corn oil and cellulose (CO/C) by upregulating apoptosis and suppressing proliferation. To elucidate the mechanisms whereby FO/P diets induce apoptosis and suppress proliferation during the tumorigenic process, we analyzed the temporal gene expression profiles from exfoliated rat colonocytes. Rats consumed diets containing FO/P or CO/C and were injected with azoxymethane (AOM; 2 times, 15 mg/kg body weight, subcutaneously). Feces collected at initiation (24 h after AOM injection) and at aberrant crypt foci (ACF) (7 wk postinjection) and tumor (28 wk postinjection) stages of colon cancer were used for poly (A)+ RNA extraction. Gene expression signatures were determined using Codelink arrays. Changes in phenotypes (ACF, apoptosis, proliferation, and tumor incidence) were measured to establish the regulatory controls contributing to the chemoprotective effects of FO/P. At initiation, FO/P downregulated the expression of 3 genes involved with cell adhesion and enhanced apoptosis compared with CO/C. At the ACF stage, the expression of genes involved in cell cycle regulation was modulated by FO/P and the zone of proliferation was reduced in FO/P rats compared with CO/C rats. FO/P also increased apoptosis and the expression of genes that promote apoptosis at the tumor endpoint compared with CO/C. We conclude that the effects of chemotherapeutic diets on epithelial cell gene expression can be monitored noninvasively throughout the tumorigenic process and that a FO/P diet is chemoprotective in part due to its ability to affect expression of genes involved in apoptosis and cell cycle regulation throughout all stages of tumorigenesis.
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Affiliation(s)
- Youngmi Cho
- Faculty of Nutrition Texas A&M University, College Station, TX 77843
| | - Hyemee Kim
- Faculty of Nutrition Texas A&M University, College Station, TX 77843
| | - Nancy D. Turner
- Faculty of Nutrition Texas A&M University, College Station, TX 77843
| | - John C. Mann
- Faculty of Nutrition Texas A&M University, College Station, TX 77843
| | - Jiawei Wei
- Department of Statistics, Texas A&M University, College Station, TX 77843
| | - Stella S. Taddeo
- Faculty of Nutrition Texas A&M University, College Station, TX 77843
| | | | - Naisyin Wang
- Department of Statistics, University of Michigan, Ann Arbor, MI 48109
| | - Marina Vannucci
- Department of Statistics, Rice University, Houston, TX 77005
| | - Raymond J. Carroll
- Department of Statistics, Texas A&M University, College Station, TX 77843
| | - Robert S. Chapkin
- Faculty of Nutrition Texas A&M University, College Station, TX 77843
| | - Joanne R. Lupton
- Faculty of Nutrition Texas A&M University, College Station, TX 77843,To whom correspondence should be addressed. E-mail:
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25
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Sutherland C. What Are the bona fide GSK3 Substrates? Int J Alzheimers Dis 2011; 2011:505607. [PMID: 21629754 PMCID: PMC3100594 DOI: 10.4061/2011/505607] [Citation(s) in RCA: 198] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2011] [Accepted: 03/09/2011] [Indexed: 01/07/2023] Open
Abstract
Nearly 100 proteins are proposed to be substrates for GSK3, suggesting that this enzyme is a fundamental regulator of almost every process in the cell, in every tissue in the body. However, it is not certain how many of these proposed substrates are regulated by GSK3 in vivo. Clearly, the identification of the physiological functions of GSK3 will be greatly aided by the identification of its bona fide substrates, and the development of GSK3 as a therapeutic target will be highly influenced by this range of actions, hence the need to accurately establish true GSK3 substrates in cells. In this paper the evidence that proposed GSK3 substrates are likely to be physiological targets is assessed, highlighting the key cellular processes that could be modulated by GSK3 activity and inhibition.
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Affiliation(s)
- Calum Sutherland
- Biomedical Research Institute, University of Dundee, Dundee DD1 9SY, UK
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26
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Litovchick L, Florens LA, Swanson SK, Washburn MP, DeCaprio JA. DYRK1A protein kinase promotes quiescence and senescence through DREAM complex assembly. Genes Dev 2011; 25:801-13. [PMID: 21498570 PMCID: PMC3078706 DOI: 10.1101/gad.2034211] [Citation(s) in RCA: 213] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2011] [Accepted: 03/01/2011] [Indexed: 12/21/2022]
Abstract
In the absence of growth signals, cells exit the cell cycle and enter into G0 or quiescence. Alternatively, cells enter senescence in response to inappropriate growth signals such as oncogene expression. The molecular mechanisms required for cell cycle exit into quiescence or senescence are poorly understood. The DREAM (DP, RB [retinoblastoma], E2F, and MuvB) complex represses cell cycle-dependent genes during quiescence. DREAM contains p130, E2F4, DP1, and a stable core complex of five MuvB-like proteins: LIN9, LIN37, LIN52, LIN54, and RBBP4. In mammalian cells, the MuvB core dissociates from p130 upon entry into the cell cycle and binds to BMYB during S phase to activate the transcription of genes expressed late in the cell cycle. We used mass spectroscopic analysis to identify phosphorylation sites that regulate the switch of the MuvB core from BMYB to DREAM. Here we report that DYRK1A can specifically phosphorylate LIN52 on serine residue 28, and that this phosphorylation is required for DREAM assembly. Inhibiting DYRK1A activity or point mutation of LIN52 disrupts DREAM assembly and reduces the ability of cells to enter quiescence or undergo Ras-induced senescence. These data reveal an important role for DYRK1A in the regulation of DREAM activity and entry into quiescence.
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Affiliation(s)
- Larisa Litovchick
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, Massachusetts 02215, USA
- Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA
| | | | - Selene K. Swanson
- Stowers Institute for Biomedical Research, Kansas City, Missouri 64110, USA
| | - Michael P. Washburn
- Stowers Institute for Biomedical Research, Kansas City, Missouri 64110, USA
- Department of Pathology and Laboratory Medicine, The University of Kansas Medical Center, Kansas City, Kansas 66160, USA
| | - James A. DeCaprio
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, Massachusetts 02215, USA
- Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA
- Belfer Institute for Applied Cancer Science, Dana-Farber Cancer Institute, Boston, Massachusetts 02215, USA
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27
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Bourogaa E, Bertrand J, Despeaux M, Jarraya R, Fabre N, Payrastre L, Demur C, Fournié JJ, Damak M, Feki AE, Racaud-Sultan C. Hammada scoparia flavonoids and rutin kill adherent and chemoresistant leukemic cells. Leuk Res 2011; 35:1093-101. [PMID: 21216465 DOI: 10.1016/j.leukres.2010.12.011] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2010] [Revised: 12/13/2010] [Accepted: 12/14/2010] [Indexed: 01/06/2023]
Abstract
In search for compounds able to reduce cell adhesion-mediated drug resistance (CAM-DR), we studied effects of Hammada scoparia extracts on leukemic cells adherent or in suspension. We show that H. scoparia flavonoidic fraction and its compound rutin induce apoptosis specifically in adherent leukemic cells and abolish CAM-DR. Importantly, rutin inhibited survival of adherent leukemic progenitors (CD34(+)38(-)123(+)) but spared normal progenitors (CD34(+)38(-)). The pro-apoptotic effects of rutin were correlated with a decrease of active GSK3β and inhibitors of GSK3β reproduced rutin-induced cytotoxicity. This study uncovers the potential of H. scoparia flavonoids and rutin to overcome CAM-DR in acute myeloid leukemia.
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MESH Headings
- Antigens, CD34/metabolism
- Apoptosis/drug effects
- Blotting, Western
- Cell Adhesion/drug effects
- Cells, Cultured
- Drug Resistance, Neoplasm/drug effects
- Flavonoids/pharmacology
- Flow Cytometry
- Glycogen Synthase Kinase 3/antagonists & inhibitors
- Glycogen Synthase Kinase 3/metabolism
- Glycogen Synthase Kinase 3 beta
- Hematopoietic Stem Cells/drug effects
- Hematopoietic Stem Cells/metabolism
- Humans
- Leukemia, Myeloid, Acute/drug therapy
- Leukemia, Myeloid, Acute/pathology
- Phytotherapy
- Rutin/pharmacology
- Scoparia/chemistry
- Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
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28
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Shookhoff JM, Gallicano GI. A new perspective on neural tube defects: folic acid and microRNA misexpression. Genesis 2010; 48:282-94. [PMID: 20229516 DOI: 10.1002/dvg.20623] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Neural tube defects (NTDs) are the second most common birth defects in the United States. It is well known that folic acid supplementation decreases about 70% of all NTDs, although the mechanism by which this occurs is still relatively unknown. The current theory is that folic acid deficiency ultimately leads to depletion of the methyl pool, leaving critical genes unmethylated, and, in turn, their improper expression leads to failure of normal neural tube development. Recently, new studies in human cell lines have shown that folic acid deficiency and DNA hypomethylation can lead to misexpression of microRNAs (miRNAs). Misexpression of critical miRNAs during neural development may lead to a subtle effect on neural gene regulation, causing the sometimes mild to severely debilitating range of phenotypes exhibited in NTDs. This review seeks to cohesively integrate current information regarding folic acid deficiency, methylation cycles, neural development, and miRNAs to propose a potential model of NTD formation. In addition, we have examined the relevant gene pathways and miRNAs that are predicted to affect them, and based on our investigation, we have devised a basic template of experiments for exploring the idea that miRNA misregulation may be linked to folic acid deficiency and NTDs.
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Affiliation(s)
- J M Shookhoff
- Department of Biochemistry and Molecular & Cellular Biology, Georgetown University Medical Center, Washington, DC 20057, USA
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29
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Schwarze F, Meraner J, Lechner M, Loidl A, Stasyk T, Laich A, Loidl P. Cell cycle-dependent acetylation of Rb2/p130 in NIH3T3 cells. Oncogene 2010; 29:5755-60. [PMID: 20676144 PMCID: PMC3007177 DOI: 10.1038/onc.2010.311] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The retinoblastoma protein (pRb) and the pRb-related proteins, p130 and p107, form the 'pocket protein' family of cell cycle regulatory factors. A well characterized function of these proteins is the cell cycle-dependent regulation of E2F-responsive genes. The biological activity of pocket proteins is regulated by phosphorylation and for the founding member pRb it has been shown that acetylation also has an important role in modulating its function during the cell cycle. Here, we show that hyperphosphorylated retinoblastoma 2 (Rb2)/p130 also exists in an acetylated form in NIH3T3 cells. Acetylated p130 is present in the nucleus but not in the cytoplasm. Acetylation is cell cycle dependent, starting in S-phase and persisting until late G(2)-period. Using recombinant p130 and truncated forms for in vitro acetylation by the acetyltransferase p300, we could identify K1079 in the C-terminal part as the major acetylation site by mass spectrometry. Minor acetylation sites were pinpointed to K1068 and K1111 in the C-terminus, and K128 and K130 in the N-terminus. The human papilloma virus 16 protein-E7 preferentially binds to acetylated p130 and significantly increases in vitro p130 acetylation by p300.
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Affiliation(s)
- F Schwarze
- Division of Molecular Biology, Biocenter, Innsbruck Medical University, Innsbruck, Austria
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30
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Jayadeva G, Kurimchak A, Garriga J, Sotillo E, Davis AJ, Haines DS, Mumby M, Graña X. B55alpha PP2A holoenzymes modulate the phosphorylation status of the retinoblastoma-related protein p107 and its activation. J Biol Chem 2010; 285:29863-73. [PMID: 20663872 DOI: 10.1074/jbc.m110.162354] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Pocket proteins negatively regulate transcription of E2F-dependent genes and progression through the G(0)/G(1) transition and the cell cycle restriction point in G(1). Pocket protein repressor activities are inactivated via phosphorylation at multiple Pro-directed Ser/Thr sites by the coordinated action of G(1) and G(1)/S cyclin-dependent kinases. These phosphorylations are reversed by the action of two families of Ser/Thr phosphatases: PP1, which has been implicated in abrupt dephosphorylation of retinoblastoma protein (pRB) in mitosis, and PP2A, which plays a role in an equilibrium that counteracts cyclin-dependent kinase (CDK) action throughout the cell cycle. However, the identity of the trimeric PP2A holoenzyme(s) functioning in this process is unknown. Here we report the identification of a PP2A trimeric holoenzyme containing B55α, which plays a major role in restricting the phosphorylation state of p107 and inducing its activation in human cells. Our data also suggest targeted selectivity in the interaction of pocket proteins with distinct PP2A holoenzymes, which is likely necessary for simultaneous pocket protein activation.
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Affiliation(s)
- Girish Jayadeva
- Fels Institute for Cancer Research and Molecular Biology, Temple University School of Medicine, Philadelphia, Pennsylvania 19140, USA
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31
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Low- and high-risk human papillomavirus E7 proteins regulate p130 differently. Virology 2010; 400:233-9. [PMID: 20189212 DOI: 10.1016/j.virol.2010.01.034] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2009] [Revised: 12/17/2009] [Accepted: 01/27/2010] [Indexed: 11/23/2022]
Abstract
The E7 protein of high-risk human papillomaviruses (HR HPVs) targets pRb family members (pRb, p107 and p130) for degradation; low-risk (LR) HPV E7 only targets p130 for degradation. The effect of HR HPV 16 E7 and LR HPV 6 E7 on p130 intracellular localization and half-life was examined. Nuclear/cytoplasmic fractionation and immunofluorescence showed that, in contrast to control and HPV 6 E7-expressing cells, a greater amount of p130 was present in the cytoplasm in the presence of HPV 16 E7. The half-life of p130, relative to control cells, was decreased in the cytoplasm in the presence of HPV 6 E7 or HPV 16 E7, but only decreased by HPV 6 E7 in the nucleus. Inhibition of proteasomal degradation extended the half-life of p130, regardless of intracellular localization. These results suggest that there may be divergent mechanisms by which LR and HR HPV E7 target p130 for degradation.
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32
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Gayer CP, Chaturvedi LS, Wang S, Craig DH, Flanigan T, Basson MD. Strain-induced proliferation requires the phosphatidylinositol 3-kinase/AKT/glycogen synthase kinase pathway. J Biol Chem 2008; 284:2001-11. [PMID: 19047055 DOI: 10.1074/jbc.m804576200] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
The intestinal epithelium is repetitively deformed by shear, peristalsis, and villous motility. Such repetitive deformation stimulates the proliferation of intestinal epithelial cells on collagen or laminin substrates via ERK, but the upstream mediators of this effect are poorly understood. We hypothesized that the phosphatidylinositol 3-kinase (PI3K)/AKT cascade mediates this mitogenic effect. PI3K, AKT, and glycogen synthase kinase-3beta (GSK-3beta) were phosphorylated by 10 cycles/min strain at an average 10% deformation, and pharmacologic blockade of these molecules or reduction by small interfering RNA (siRNA) prevented the mitogenic effect of strain in Caco-2 or IEC-6 intestinal epithelial cells. Strain MAPK activation required PI3K but not AKT. AKT isoform-specific siRNA transfection demonstrated that AKT2 but not AKT1 is required for GSK-3beta phosphorylation and the strain mitogenic effect. Furthermore, overexpression of AKT1 or an AKT chimera including the PH domain and hinge region of AKT2 and the catalytic domain and C-tail of AKT1 prevented strain activation of GSK-3beta, but overexpression of AKT2 or a chimera including the PH domain and hinge region of AKT1 and the catalytic domain and C-tail of AKT2 did not. These data delineate a role for PI3K, AKT2, and GSK-3beta in the mitogenic effect of strain. PI3K is required for both ERK and AKT2 activation, whereas AKT2 is sequentially required for GSK-3beta. Furthermore, AKT2 specificity requires its catalytic domain and tail region. Manipulating this pathway may prevent mucosal atrophy and maintain the mucosal barrier in conditions such as ileus, sepsis, and prolonged fasting when peristalsis and villous motility are decreased and the mucosal barrier fails.
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Affiliation(s)
- Christopher P Gayer
- Department of Surgery, John D. Dingell Veterans Affairs Medical Center, Detroit, Michigan 48301, USA
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33
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Eun Jeoung L, Sung Hee H, Jaesun C, Sung Hwa S, Kwang Hum Y, Min Kyoung K, Tae Yoon P, Sang Sun K. Regulation of glycogen synthase kinase 3beta functions by modification of the small ubiquitin-like modifier. Open Biochem J 2008; 2:67-76. [PMID: 18949077 PMCID: PMC2570553 DOI: 10.2174/1874091x00802010067] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2008] [Revised: 02/14/2006] [Accepted: 02/03/2008] [Indexed: 01/29/2023] Open
Abstract
Modification of the Small Ubiquitin-like Modifier (SUMO) (SUMOylation) appears to regulate diverse cellular processes, including nuclear transport, signal transduction, apoptosis, autophagy, cell cycle control, ubiquitin-dependent degradation and gene transcription. Glycogen synthase kinase 3beta (GSK 3beta) is a serine/threonine kinase that is thought to contribute to a variety of biological events, including embryonic development, metabolism, tumorigenesis, and cell death. GSK 3beta is a constitutively active kinase that regulates many intracellular signaling pathways by phosphorylating substrates such as beta-catenin. We noticed that the putative SUMOylation sites are localized on K(292 )residueof (291)FKFPQ(295) in GSK 3beta based on analysis of the SUMOylation consensus sequence. In this report, we showed that the SUMOylation of GSK 3beta occurs on its K(292) residue, and this modification promotes its nuclear localization in COS-1. Additionally, our data showed that the GSK 3beta SUMO mutant (K292R) decreased its kinase activity and protein stability, affecting cell death. Therefore, our observations at first time suggested that SUMOylation on the K(292) residue of GSK 3beta might be a GSK 3beta regulation mechanism for its kinase activation, subcellular localization, protein stability, and cell apoptosis.
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Affiliation(s)
- Lee Eun Jeoung
- School of Science Education, Chungbuk National University, Gaeshin-dong, Heungdok-gu, Cheongju, Chungbuk, 361-763, Republic of Korea
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34
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A comprehensive modular map of molecular interactions in RB/E2F pathway. Mol Syst Biol 2008; 4:173. [PMID: 18319725 PMCID: PMC2290939 DOI: 10.1038/msb.2008.7] [Citation(s) in RCA: 92] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2007] [Accepted: 01/23/2008] [Indexed: 12/16/2022] Open
Abstract
We present, here, a detailed and curated map of molecular interactions taking place in the regulation of the cell cycle by the retinoblastoma protein (RB/RB1). Deregulations and/or mutations in this pathway are observed in most human cancers. The map was created using Systems Biology Graphical Notation language with the help of CellDesigner 3.5 software and converted into BioPAX 2.0 pathway description format. In the current state the map contains 78 proteins, 176 genes, 99 protein complexes, 208 distinct chemical species and 165 chemical reactions. Overall, the map recapitulates biological facts from approximately 350 publications annotated in the diagram. The network contains more details about RB/E2F interaction network than existing large-scale pathway databases. Structural analysis of the interaction network revealed a modular organization of the network, which was used to elaborate a more summarized, higher-level representation of RB/E2F network. The simplification of complex networks opens the road for creating realistic computational models of this regulatory pathway.
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35
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Fields AL, Soprano DR, Soprano KJ. Retinoids in biological control and cancer. J Cell Biochem 2008; 102:886-98. [PMID: 17902161 DOI: 10.1002/jcb.21530] [Citation(s) in RCA: 92] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
More than 80 years ago, Wolbach and Howe provided the first evidence suggesting a link between alterations within human cells that lead to malignancies and vitamin A deficiencies (Wolbach and Howe 1925 Nutr. Rev. 36: 16-19). Since that time, epidemiological, preclinical and clinical studies have established a causative relationship between vitamin A deficiency and cancer. Laboratory research has provided insight into the intracellular targets, various signaling cascades and physiological effects of the biologically-active natural and synthetic derivatives of vitamin A, known as retinoids. Collectively, this body of research supports the concept of retinoids as chemopreventive and chemotherapeutic agents that can prevent epithelial cell tumorigenesis by directing the cells to either differentiate, growth arrest, or undergo apoptosis, thus preventing or reversing neoplasia. Continued refinement of the retinoid signaling pathway is essential to establishing their use as effective therapeutics for tumor subtypes whose oncogenic intracellular signaling pathways can be blocked or reversed by treatment with retinoids.
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Affiliation(s)
- Anthonise Louis Fields
- Department of Microbiology & Immunology, Temple University School of Medicine, Philadelphia, Pennsylvania 19140, USA
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36
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Yeste-Velasco M, Folch J, Trullàs R, Abad MA, Enguita M, Pallàs M, Camins A. Glycogen synthase kinase-3 is involved in the regulation of the cell cycle in cerebellar granule cells. Neuropharmacology 2007; 53:295-307. [PMID: 17612578 DOI: 10.1016/j.neuropharm.2007.05.012] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2006] [Revised: 04/02/2007] [Accepted: 05/16/2007] [Indexed: 01/17/2023]
Abstract
Recent studies have demonstrated that neuronal reentry in the cell cycle and specifically the expression of the transcription factor E2F-1, constitutes a pathway that may be involved in neuronal apoptosis after serum and potassium withdrawal. Other enzymes such as glycogen synthase kinase-3beta (GSK-3beta) are also involved in this apoptotic stimulus, and thus in the process of neuronal cell death. Primary cerebellar granule cells (CGNs) were used in this study to determine whether pharmacological inhibition of GSK-3beta is involved in neuronal modulation of the cell cycle, and specifically in the regulation of E2F-1 and retinoblastoma protein (Rb). CGNs showed a dramatic increase in GSK-3beta activity after 2h of serum and potassium deprivation. Immunoblot and activity assays revealed that lithium and SB415286 inhibit fully the activation of GSK-3beta and attenuate the expression of cyclin D, cyclin E, pRb phosphorylation and the transcription factor E2F-1. These data were confirmed using AR-014418, a selective GSK-3beta inhibitor that prevents the expression of cell-cycle proteins. Our data indicate that GSK-3beta inhibition regulates, in part, the cell cycle in CGNs by inhibiting Rb phosphorylation and thus inhibiting E2F-1 activity. However, the selective inhibition of GSK-3beta with AR-A014418 had not effect on cell viability or apoptosis mediated by S/K withdrawal. Furthermore, our results suggest that selective GSK-3beta inhibition is not sufficient to protect against apoptosis in this S/K withdrawal model, indicating that Li(+) and SB415286 neuroprotective effects are mediated by the inhibition of additional targets to GSK3beta. Therefore, there is a connection between cell cycle and GSK-3beta activation and that these, along with other mechanisms, are involved in the molecular paths leading to the apoptotic process of rat CGNs triggered by S/K withdrawal.
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Affiliation(s)
- M Yeste-Velasco
- Unitat de Farmacologia, Facultat de Farmàcia Universitat de Barcelona, Nucli Universitari de Pedralbes, E-08028 Barcelona, Spain
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37
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Litovchick L, Sadasivam S, Florens L, Zhu X, Swanson SK, Velmurugan S, Chen R, Washburn MP, Liu XS, DeCaprio JA. Evolutionarily conserved multisubunit RBL2/p130 and E2F4 protein complex represses human cell cycle-dependent genes in quiescence. Mol Cell 2007; 26:539-51. [PMID: 17531812 DOI: 10.1016/j.molcel.2007.04.015] [Citation(s) in RCA: 299] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2006] [Revised: 03/12/2007] [Accepted: 04/20/2007] [Indexed: 02/02/2023]
Abstract
The mammalian Retinoblastoma (RB) family including pRB, p107, and p130 represses E2F target genes through mechanisms that are not fully understood. In D. melanogaster, RB-dependent repression is mediated in part by the multisubunit protein complex Drosophila RBF, E2F, and Myb (dREAM) that contains homologs of the C. elegans synthetic multivulva class B (synMuvB) gene products. Using an integrated approach combining proteomics, genomics, and bioinformatic analyses, we identified a p130 complex termed DP, RB-like, E2F, and MuvB (DREAM) that contains mammalian homologs of synMuvB proteins LIN-9, LIN-37, LIN-52, LIN-54, and LIN-53/RBBP4. DREAM bound to more than 800 human promoters in G0 and was required for repression of E2F target genes. In S phase, MuvB proteins dissociated from p130 and formed a distinct submodule that bound MYB. This work reveals an evolutionarily conserved multisubunit protein complex that contains p130 and E2F4, but not pRB, and mediates the repression of cell cycle-dependent genes in quiescence.
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Affiliation(s)
- Larisa Litovchick
- Department of Medical Oncology, Dana-Farber Cancer Institute and Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, 44 Binney Street, Boston, MA 02115, USA
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38
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Liu M, Tu X, Ferrari-Amorotti G, Calabretta B, Baserga R. Downregulation of the upstream binding factor1 by glycogen synthase kinase3beta in myeloid cells induced to differentiate. J Cell Biochem 2007; 100:1154-69. [PMID: 17063482 DOI: 10.1002/jcb.21103] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The upstream binding factor 1 (UBF1), one of the proteins that regulate the activity of RNA polymerase I, is downregulated in 32D myeloid cells induced to differentiate into granulocytes, either by the type 1 insulin-like growth factor (IGF-1) or the granulocytic colony stimulating factor (G-CSF). Downregulation of UBF1 is largely due to protein degradation, while mRNA levels are not affected. Inhibition of UBF1 degradation by lithium chloride (LiCl)and lactacystin suggest a role of glycogen synthase kinase beta (GSK3beta) in a proteasome-dependent degradation of UBF. GSK3beta phosphorylates in vitro and in vivo the UBF protein, which has five putative motifs for phosphorylation by GSK3beta. Elimination and/or mutations of these motifs stabilize the UBF1 protein even in cells induced to differentiate. Conversely, a stably transfected, constitutively active GSK3beta accelerates the downregulation of UBF1. We show further that activation of the differentiating protein C/EPBalpha in 32D cells transformed by the oncogenic BCR/ABL protein causes downregulation of UBF1. Finally, inhibition of differentiation of myeloid cells by a dominant negative mutant of Stat3 stabilizes the UBF1 protein, while rapamycin-induced differentiation of myeloid cells downregulates UBF1 levels. Taken together, our results indicate that the induction of granulocytic differentiation in 32D murine myeloid cells causes the degradation of UBF1, via GSK3beta and the proteasome pathway.
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Affiliation(s)
- Mingli Liu
- Kimmel Cancer Center, Thomas Jefferson University, 624 Bluemle, Life Sciences Building, Philadelphia, Pennsylvania 19107, USA
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39
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Danek EI, Tcherkezian J, Triki I, Meriane M, Lamarche-Vane N. Glycogen synthase kinase-3 phosphorylates CdGAP at a consensus ERK 1 regulatory site. J Biol Chem 2006; 282:3624-31. [PMID: 17158447 DOI: 10.1074/jbc.m610073200] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Rho GTPases regulate a multitude of cellular processes from cytoskeletal reorganization to gene transcription and are negatively regulated by GTPase-activating proteins (GAPs). Cdc42 GTPase-activating protein (CdGAP) is a ubiquitously expressed GAP for Rac1 and Cdc42. In this study, we set out to identify CdGAP-binding partners and, using a yeast two-hybrid approach, glycogen synthase kinase 3alpha (GSK-3alpha) was identified as a partner for CdGAP. GSK-3 exists in two isoforms, alpha and beta, and is involved in regulating many cellular functions from insulin response to tumorigenesis. We show that GSK-3alpha and -beta interact with CdGAP in mammalian cells. We also demonstrate that GSK-3 phosphorylates CdGAP both in vitro and in vivo on Thr-776, which we have previously shown to be an ERK 1/2 phosphorylation site involved in CdGAP regulation. We report that the mRNA and protein levels of CdGAP are increased upon serum stimulation and that GSK-3 activity is necessary for the up-regulation of the protein levels of CdGAP but not for the increase in mRNA. We conclude that GSK-3 is an important regulator of CdGAP and that regulation of CdGAP protein levels by serum presents a novel mechanism for cells to control Cdc42/Rac1 GTPase signaling pathways.
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Affiliation(s)
- Eric Ian Danek
- Department of Anatomy and Cell Biology, McGill University, Montreal, Quebec H3A 2B2, Canada
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40
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Soprano KJ, Purev E, Vuocolo S, Soprano DR. Rb2/p130 and protein phosphatase 2A: key mediators of ovarian carcinoma cell growth suppression by all-trans retinoic acid. Oncogene 2006; 25:5315-25. [PMID: 16936753 DOI: 10.1038/sj.onc.1209679] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Despite a number of attempts to improve treatment of ovarian cancer, it remains the most common cause of death from gynecological cancers. Thus, it is very important to identify more effective drugs for treatment and prevention of ovarian cancer. All-trans-retinoic acid (ATRA) has been shown to arrest the growth of ovarian carcinoma cells in G0/G1 and to significantly elevate levels of Rb2/p130 protein, a member of the retinoblastoma family of tumor suppressors. As ATRA treatment leads to a significant increase in the amount of Rb2/p130 protein but not mRNA, the elevated levels of Rb2/p130 protein is likely the result of increased stability. In studies to elucidate the mechanism by which ATRA alters Rb2/p130 stability in ovarian cancer cells, it was determined that PP2A, a serine/threonine phosphatase, binds and dephosphorylates Rb2/p130. Dephosphorylated Rb2/p130 exhibits decreased ubiquitination and thus is not degraded by the proteasome. The sites at which PP2A catalytic subunit (PP2Ac) interacts with Rb2/p130 have been localized to the NLS in the C-terminus of Rb2/p130. These sites are also involved in the interaction of Rb/p130 with importin beta and importin alpha, members of the nuclear transport machinery. It is known that importin alpha recognizes a NLS on a target protein and importin beta binds the nuclear pore complex. Moreover, it has been shown that the binding of importin alpha to NLS significantly decreases with phosphorylation of NLS. In ATRA-treated ovarian carcinoma cells, PP2A binds to Rb2/p130 and dephosphorylates the NLS of Rb2/p130 leading to the interaction of importin alpha with Rb2/p130. Importin beta then binds to the importin alpha-Rb2/p130 complex, leading to the translocation of the Rb2/p130 to the nucleus where it acts to arrest ovarian cancer cells in G1 and suppress proliferation.
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Affiliation(s)
- K J Soprano
- Department of Microbiology and Immunology, Temple University School of Medicine, Philadelphia, PA 19140, USA.
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41
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Jackson JG, Pereira-Smith OM. Primary and compensatory roles for RB family members at cell cycle gene promoters that are deacetylated and downregulated in doxorubicin-induced senescence of breast cancer cells. Mol Cell Biol 2006; 26:2501-10. [PMID: 16537896 PMCID: PMC1430319 DOI: 10.1128/mcb.26.7.2501-2510.2006] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
When treated with DNA-damaging chemotherapy agents, many cancer cells, in vivo and in vitro, undergo a terminal growth arrest and acquire a senescence-like phenotype. We investigated the molecular basis for this in breast cancer cells following a 2-hour treatment with 1 muM doxorubicin. Treated cells arrested in G1 and G2 phases of the cell cycle, with concomitant reductions in S-phase and G2-M regulatory genes. p53 and p21 protein levels increased within hours after treatment and were maintained for 5 to 6 days but were reduced 8 days posttreatment, though the cells remained growth arrested. Levels of p130 rose after drug treatment, and it was the primary RB family member recruited to the S-phase promoters cyclin A and PCNA and G2-M promoters cyclin B and cdc2, remaining present for the entire 8-day time period. In contrast, p107 protein and promoter occupancy levels declined sharply after drug treatment. RB was recruited to only the PCNA promoter. In MCF-7 cells with p130 knockdown, p107 compensated for p130 loss at all cell cycle gene promoters examined, allowing cells to retain the growth arrest phenotype. Cells with p130 and p107 knockdown similarly arrested, while cells with knockdown of all three family members failed to downregulate cyclin A and cyclin B. These results demonstrate a mechanistic role for p130 and compensatory roles for p107 and RB in the long-term senescence-like growth arrest response of breast cancer cells to DNA damage.
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Affiliation(s)
- James G Jackson
- University of Texas Health Science Center at San Antonio, Department of Cellular and Structural Biology, Sam and Ann Barshop Institute for Longevity and Aging Studies, San Antonio, Texas 78245-3207, USA.
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42
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Tahimic CGT, Tomimatsu N, Nishigaki R, Fukuhara A, Toda T, Kaibuchi K, Shiota G, Oshimura M, Kurimasa A. Evidence for a role of Collapsin response mediator protein-2 in signaling pathways that regulate the proliferation of non-neuronal cells. Biochem Biophys Res Commun 2006; 340:1244-50. [PMID: 16414354 DOI: 10.1016/j.bbrc.2005.12.132] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2005] [Accepted: 12/18/2005] [Indexed: 11/23/2022]
Abstract
Collapsin response mediator protein-2 or Crmp-2 plays a critical role in the establishment of neuronal polarity. In this study, we present evidence that apart from its functions in neurodevelopment, Crmp-2 is also involved in pathways that regulate the proliferation of non-neuronal cells through its phosphorylation by regulatory proteins. We show that Crmp-2 undergoes dynamic phosphorylation changes in response to contact inhibition-induced quiescence and that hyperphosphorylation of Crmp-2 occurs in a tumor. We further suggest that de-regulation of Crmp-2 phosphorylation levels at certain amino acid residues may lead to aberrant cell proliferation and consequently, tumorigenesis.
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Affiliation(s)
- Candice Ginn T Tahimic
- Department of Genetic Medicine and Regenerative Therapeutics, Graduate School of Medical Science, Tottori University, 86 Nishi-cho, Yonago, Tottori 683-8503, Japan
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43
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Dannenberg JH, te Riele HPJ. The retinoblastoma gene family in cell cycle regulation and suppression of tumorigenesis. Results Probl Cell Differ 2006; 42:183-225. [PMID: 16903212 DOI: 10.1007/400_002] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Since its discovery in 1986, as the first tumor suppressor gene, the retinoblastoma gene (Rb) has been extensively studied. Numerous biochemical and genetic studies have elucidated in great detail the function of the Rb gene and placed it at the heart of the molecular machinery controlling the cell cycle. As more insight was gained into the genetic events required for oncogenic transformation, it became clear that the retinoblastoma gene is connected to biochemical pathways that are dysfunctional in virtually all tumor types. Besides regulating the E2F transcription factors, pRb is involved in numerous biological processes such as apoptosis, DNA repair, chromatin modification, and differentiation. Further complexity was added to the system with the discovery of p107 and p130, two close homologs of Rb. Although the three family members share similar functions, it is becoming clear that these proteins also have unique functions in differentiation and regulation of transcription. In contrast to Rb, p107 and p130 are rarely found inactivated in human tumors. Yet, evidence is accumulating that these proteins are part of a "tumor-surveillance" mechanism and can suppress tumorigenesis. Here we provide an overview of the knowledge obtained from studies involving the retinoblastoma gene family with particular focus on its role in suppressing tumorigenesis.
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Affiliation(s)
- Jan-Hermen Dannenberg
- Department of Medical Oncology, Dana-Farber Cancer Institute and Harvard Medical School, Boston, Massachusetts, USA.
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Zhang B, Chen W, Roman A. The E7 proteins of low- and high-risk human papillomaviruses share the ability to target the pRB family member p130 for degradation. Proc Natl Acad Sci U S A 2005; 103:437-42. [PMID: 16381817 PMCID: PMC1326189 DOI: 10.1073/pnas.0510012103] [Citation(s) in RCA: 129] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
High-risk human papillomaviruses (HPVs) (e.g., HPV-16) cause anogenital and head and neck cancers, and low-risk HPVs (e.g., HPV-6) cause benign hyperproliferative disease. The E7 protein of HPV-16 binds all retinoblastoma tumor suppressor protein (pRB) family members with higher affinity than HPV-6E7. The HPV-16 E7 protein has been reported to target pRB family members for degradation and to immortalize cells. Here we tested the hypothesis that the low-risk E7 protein has an intrinsic ability to decrease expression of pRB family members. First, we introduced a high-affinity pRB-binding site into HPV-6 E7 (6E7G22D) and showed that, in human foreskin keratinocytes, HPV-6 E7G22D decreased the level of pRB protein but not pRB mRNA. Second, we analyzed the ability of wild-type HPV-6 E7 to destabilize the other pRB family members, p107 and p130. HPV-6 E7, like HPV-16 E7, decreased the level of p130 protein. This decrease was inhibited by MG132, a proteasome inhibitor. Binding of HPV-6 E7 to p130 was necessary but not sufficient to decrease the level of p130. Furthermore, the destabilization of p130 correlated with a decrease in the expression of involucrin, a differentiation marker. We suggest that the shared activity of HPV-16 E7 and HPV-6 E7 to destabilize p130 and decrease or delay differentiation may be related to the role of E7 in the HPV life cycle. The added ability of HPV-16 E7 to regulate pRB and p107 may be related to oncogenic activity.
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Affiliation(s)
- Benyue Zhang
- Department of Microbiology and Immunology and The Walther Oncology Center, Indiana University School of Medicine and The Walther Cancer Institute, Indianapolis, IN 46202, USA
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