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Dias MH, Friskes A, Wang S, Fernandes Neto JM, van Gemert F, Mourragui S, Papagianni C, Kuiken HJ, Mainardi S, Alvarez-Villanueva D, Lieftink C, Morris B, Dekker A, van Dijk E, Wilms LHS, da Silva MS, Jansen RA, Mulero-Sanchez A, Malzer E, Vidal A, Santos C, Salazar R, Wailemann RAM, Torres TEP, De Conti G, Raaijmakers JA, Snaebjornsson P, Yuan S, Qin W, Kovach JS, Armelin HA, Te Riele H, van Oudernaarden A, Jin H, Beijersbergen RL, Villanueva A, Medema RH, Bernards R. Paradoxical activation of oncogenic signaling as a cancer treatment strategy. Cancer Discov 2024:742013. [PMID: 38533987 DOI: 10.1158/2159-8290.cd-23-0216] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Revised: 12/06/2023] [Accepted: 03/19/2024] [Indexed: 03/28/2024]
Abstract
Cancer homeostasis depends on a balance between activated oncogenic pathways driving tumorigenesis and engagement of stress-response programs that counteract the inherent toxicity of such aberrant signaling. While inhibition of oncogenic signaling pathways has been explored extensively, there is increasing evidence that overactivation of the same pathways can also disrupt cancer homeostasis and cause lethality. We show here that inhibition of Protein Phosphatase 2A (PP2A) hyperactivates multiple oncogenic pathways and engages stress responses in colon cancer cells. Genetic and compound screens identify combined inhibition of PP2A and WEE1 as synergistic in multiple cancer models by collapsing DNA replication and triggering premature mitosis followed by cell death. This combination also suppressed the growth of patient-derived tumors in vivo. Remarkably, acquired resistance to this drug combination suppressed the ability of colon cancer cells to form tumors in vivo. Our data suggest that paradoxical activation of oncogenic signaling can result in tumor suppressive resistance.
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Affiliation(s)
| | - Anoek Friskes
- The Netherlands Cancer Institute, Amsterdam, Netherlands
| | - Siying Wang
- Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | | | | | - Soufiane Mourragui
- Hubrecht Institute for Developmental Biology and Stem Cell Research, Utrecht, Netherlands
| | | | | | - Sara Mainardi
- The Netherlands Cancer Institute, Amsterdam, Netherlands
| | | | - Cor Lieftink
- The Netherlands Cancer Institute, Amsterdam, Netherlands
| | - Ben Morris
- The Netherlands Cancer Institute, Amsterdam, Netherlands
| | - Anna Dekker
- The Netherlands Cancer Institute, Amsterdam, Netherlands
| | - Emma van Dijk
- The Netherlands Cancer Institute, Amsterdam, Netherlands
| | | | | | - Robin A Jansen
- Netherlands Cancer Institute-Antoni van Leeuwenhoek Hospital, Amsterdam, Netherlands
| | | | - Elke Malzer
- The Netherlands Cancer Institute, Amsterdam, Netherlands
| | - August Vidal
- Bellvitge University Hospital, L'Hospitalet de Llobregat, Barcelona, Spain
| | - Cristina Santos
- Catalan Institute of Oncology (ICO) - Bellvitge Biomedical Research Institute (IDIBELL)-CIBERONC, L'Hospitalet de Llobregat, L'Hospitalet de Llobregat, Spain
| | - Ramon Salazar
- Instituto Catalan de Oncología-IDIBELL, Hospitalet de Llobregat, Barcelona, Spain
| | | | | | | | | | | | | | - Wenxin Qin
- Shanghai Cancer Institute, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - John S Kovach
- Lixte Biotechnology Holdings, Inc., East Setauket, NY, United States
| | | | - Hein Te Riele
- Netherlands Cancer Institute, Amsterdam, N, Netherlands
| | | | - Haojie Jin
- State Key Laboratory of Oncogenes and Related Genes, Shanghai, China
| | | | - Alberto Villanueva
- Catalan Institute of Oncology (ICO/IDIBELL), L'Hospitalet de Llobregat, Barcelona, Spain
| | - Rene H Medema
- University Medical Center Utrecht, Amsterdam, Netherlands
| | - Rene Bernards
- The Netherlands Cancer Institute, Amsterdam, Netherlands
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2
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McCabe CV, Price PD, Codner GF, Allan AJ, Caulder A, Christou S, Loeffler J, Mackenzie M, Malzer E, Mianné J, Nowicki KJ, O’Neill EJ, Pike FJ, Hutchison M, Petit-Demoulière B, Stewart ME, Gates H, Wells S, Sanderson ND, Teboul L. Long-read sequencing for fast and robust identification of correct genome-edited alleles: PCR-based and Cas9 capture methods. PLoS Genet 2024; 20:e1011187. [PMID: 38457464 PMCID: PMC10954187 DOI: 10.1371/journal.pgen.1011187] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2023] [Revised: 03/20/2024] [Accepted: 02/20/2024] [Indexed: 03/10/2024] Open
Abstract
BACKGROUND Recent developments in CRISPR/Cas9 genome-editing tools have facilitated the introduction of precise alleles, including genetic intervals spanning several kilobases, directly into the embryo. However, the introduction of donor templates, via homology directed repair, can be erroneous or incomplete and these techniques often produce mosaic founder animals. Thus, newly generated alleles must be verified at the sequence level across the targeted locus. Screening for the presence of the desired mutant allele using traditional sequencing methods can be challenging due to the size of the interval to be sequenced, together with the mosaic nature of founders. METHODOLOGY/PRINCIPAL FINDINGS In order to help disentangle the genetic complexity of these animals, we tested the application of Oxford Nanopore Technologies long-read sequencing at the targeted locus and found that the achievable depth of sequencing is sufficient to offset the sequencing error rate associated with the technology used to validate targeted regions of interest. We have assembled an analysis workflow that facilitates interrogating the entire length of a targeted segment in a single read, to confirm that the intended mutant sequence is present in both heterozygous animals and mosaic founders. We used this workflow to compare the output of PCR-based and Cas9 capture-based targeted sequencing for validation of edited alleles. CONCLUSION Targeted long-read sequencing supports in-depth characterisation of all experimental models that aim to produce knock-in or conditional alleles, including those that contain a mix of genome-edited alleles. PCR- or Cas9 capture-based modalities bring different advantages to the analysis.
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Affiliation(s)
| | - Peter D. Price
- The Mary Lyon Centre, MRC Harwell, Oxfordshire, United Kingdom
| | - Gemma F. Codner
- The Mary Lyon Centre, MRC Harwell, Oxfordshire, United Kingdom
| | | | - Adam Caulder
- The Mary Lyon Centre, MRC Harwell, Oxfordshire, United Kingdom
| | | | - Jorik Loeffler
- The Mary Lyon Centre, MRC Harwell, Oxfordshire, United Kingdom
| | | | - Elke Malzer
- The Mary Lyon Centre, MRC Harwell, Oxfordshire, United Kingdom
| | - Joffrey Mianné
- The Mary Lyon Centre, MRC Harwell, Oxfordshire, United Kingdom
| | | | | | - Fran J. Pike
- The Mary Lyon Centre, MRC Harwell, Oxfordshire, United Kingdom
| | - Marie Hutchison
- The Mary Lyon Centre, MRC Harwell, Oxfordshire, United Kingdom
| | - Benoit Petit-Demoulière
- Université de Strasbourg, CNRS, INSERM, Institut Clinique de la Souris (ICS), PHENOMIN, CELPHEDIA, Illkirch, France
| | | | - Hilary Gates
- The Mary Lyon Centre, MRC Harwell, Oxfordshire, United Kingdom
- Mammalian Genetics Unit, MRC Harwell, Oxfordshire, United Kingdom
| | - Sara Wells
- The Mary Lyon Centre, MRC Harwell, Oxfordshire, United Kingdom
| | - Nicholas D. Sanderson
- Nuffield Department of Clinical Medicine, University of Oxford, John Radcliffe Hospital, Oxford, United Kingdom
| | - Lydia Teboul
- The Mary Lyon Centre, MRC Harwell, Oxfordshire, United Kingdom
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Andronikou C, Burdova K, Dibitetto D, Lieftink C, Malzer E, Kuiken HJ, Gogola E, Ray Chaudhuri A, Beijersbergen RL, Hanzlikova H, Jonkers J, Rottenberg S. PARG-deficient tumor cells have an increased dependence on EXO1/FEN1-mediated DNA repair. EMBO J 2024; 43:1015-1042. [PMID: 38360994 PMCID: PMC10943112 DOI: 10.1038/s44318-024-00043-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2023] [Revised: 01/22/2024] [Accepted: 01/23/2024] [Indexed: 02/17/2024] Open
Abstract
Targeting poly(ADP-ribose) glycohydrolase (PARG) is currently explored as a therapeutic approach to treat various cancer types, but we have a poor understanding of the specific genetic vulnerabilities that would make cancer cells susceptible to such a tailored therapy. Moreover, the identification of such vulnerabilities is of interest for targeting BRCA2;p53-deficient tumors that have acquired resistance to poly(ADP-ribose) polymerase inhibitors (PARPi) through loss of PARG expression. Here, by performing whole-genome CRISPR/Cas9 drop-out screens, we identify various genes involved in DNA repair to be essential for the survival of PARG;BRCA2;p53-deficient cells. In particular, our findings reveal EXO1 and FEN1 as major synthetic lethal interactors of PARG loss. We provide evidence for compromised replication fork progression, DNA single-strand break repair, and Okazaki fragment processing in PARG;BRCA2;p53-deficient cells, alterations that exacerbate the effects of EXO1/FEN1 inhibition and become lethal in this context. Since this sensitivity is dependent on BRCA2 defects, we propose to target EXO1/FEN1 in PARPi-resistant tumors that have lost PARG activity. Moreover, EXO1/FEN1 targeting may be a useful strategy for enhancing the effect of PARG inhibitors in homologous recombination-deficient tumors.
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Affiliation(s)
- Christina Andronikou
- Institute of Animal Pathology, Vetsuisse Faculty, University of Bern, 3012, Bern, Switzerland
- Division of Molecular Pathology, The Netherlands Cancer Institute, 1066CX, Amsterdam, The Netherlands
- Oncode Institute, Amsterdam, The Netherlands
- Cancer Therapy Resistance Cluster and Bern Center for Precision Medicine, Department for Biomedical Research, University of Bern, 3088, Bern, Switzerland
| | - Kamila Burdova
- Laboratory of Genome Dynamics, Institute of Molecular Genetics of the Czech Academy of Sciences, 142 20, Prague 4, Czech Republic
| | - Diego Dibitetto
- Institute of Animal Pathology, Vetsuisse Faculty, University of Bern, 3012, Bern, Switzerland
- Cancer Therapy Resistance Cluster and Bern Center for Precision Medicine, Department for Biomedical Research, University of Bern, 3088, Bern, Switzerland
| | - Cor Lieftink
- Division of Molecular Carcinogenesis, The Netherlands Cancer Institute, 1066CX, Amsterdam, The Netherlands
- The Netherlands Cancer Institute Robotics and Screening Center, The Netherlands Cancer Institute, 1066CX, Amsterdam, The Netherlands
| | - Elke Malzer
- Division of Molecular Carcinogenesis, The Netherlands Cancer Institute, 1066CX, Amsterdam, The Netherlands
- The Netherlands Cancer Institute Robotics and Screening Center, The Netherlands Cancer Institute, 1066CX, Amsterdam, The Netherlands
| | - Hendrik J Kuiken
- Division of Molecular Carcinogenesis, The Netherlands Cancer Institute, 1066CX, Amsterdam, The Netherlands
- The Netherlands Cancer Institute Robotics and Screening Center, The Netherlands Cancer Institute, 1066CX, Amsterdam, The Netherlands
| | - Ewa Gogola
- Division of Molecular Pathology, The Netherlands Cancer Institute, 1066CX, Amsterdam, The Netherlands
| | - Arnab Ray Chaudhuri
- Department of Molecular Genetics, Erasmus MC Cancer Institute, Erasmus University Medical Center, 3015GD, Rotterdam, The Netherlands
| | - Roderick L Beijersbergen
- Division of Molecular Carcinogenesis, The Netherlands Cancer Institute, 1066CX, Amsterdam, The Netherlands
- The Netherlands Cancer Institute Robotics and Screening Center, The Netherlands Cancer Institute, 1066CX, Amsterdam, The Netherlands
| | - Hana Hanzlikova
- Institute of Animal Pathology, Vetsuisse Faculty, University of Bern, 3012, Bern, Switzerland
- Laboratory of Genome Dynamics, Institute of Molecular Genetics of the Czech Academy of Sciences, 142 20, Prague 4, Czech Republic
| | - Jos Jonkers
- Division of Molecular Pathology, The Netherlands Cancer Institute, 1066CX, Amsterdam, The Netherlands.
- Oncode Institute, Amsterdam, The Netherlands.
| | - Sven Rottenberg
- Institute of Animal Pathology, Vetsuisse Faculty, University of Bern, 3012, Bern, Switzerland.
- Division of Molecular Pathology, The Netherlands Cancer Institute, 1066CX, Amsterdam, The Netherlands.
- Cancer Therapy Resistance Cluster and Bern Center for Precision Medicine, Department for Biomedical Research, University of Bern, 3088, Bern, Switzerland.
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Dickens JA, Malzer E, Chambers JE, Marciniak SJ. Pulmonary endoplasmic reticulum stress-scars, smoke, and suffocation. FEBS J 2019; 286:322-341. [PMID: 29323786 DOI: 10.1111/febs.14381] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2017] [Revised: 12/11/2017] [Accepted: 01/08/2018] [Indexed: 12/14/2022]
Abstract
Protein misfolding within the endoplasmic reticulum (ER stress) can be a cause or consequence of pulmonary disease. Mutation of proteins restricted to the alveolar type II pneumocyte can lead to inherited forms of pulmonary fibrosis, but even sporadic cases of pulmonary fibrosis appear to be strongly associated with activation of the unfolded protein response and/or the integrated stress response. Inhalation of smoke can impair protein folding and may be an important cause of pulmonary ER stress. Similarly, tissue hypoxia can lead to impaired protein homeostasis (proteostasis). But the mechanisms linking smoke and hypoxia to ER stress are only partially understood. In this review, we will examine the role of ER stress in the pathogenesis of lung disease by focusing on fibrosis, smoke, and hypoxia.
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Affiliation(s)
- Jennifer A Dickens
- Cambridge Institute for Medical Research (CIMR), University of Cambridge, UK
| | - Elke Malzer
- Cambridge Institute for Medical Research (CIMR), University of Cambridge, UK
| | - Joseph E Chambers
- Cambridge Institute for Medical Research (CIMR), University of Cambridge, UK
| | - Stefan J Marciniak
- Cambridge Institute for Medical Research (CIMR), University of Cambridge, UK
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5
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Malzer E, Dominicus CS, Chambers JE, Dickens JA, Mookerjee S, Marciniak SJ. The integrated stress response regulates BMP signalling through effects on translation. BMC Biol 2018; 16:34. [PMID: 29609607 PMCID: PMC5881181 DOI: 10.1186/s12915-018-0503-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2018] [Accepted: 03/08/2018] [Indexed: 12/29/2022] Open
Abstract
Background Developmental pathways must be responsive to the environment. Phosphorylation of eIF2α enables a family of stress-sensing kinases to trigger the integrated stress response (ISR), which has pro-survival and developmental consequences. Bone morphogenetic proteins (BMPs) regulate multiple developmental processes in organisms from insects to mammals. Results Here we show in Drosophila that GCN2 antagonises BMP signalling through direct effects on translation and indirectly via the transcription factor crc (dATF4). Expression of a constitutively active GCN2 or loss of the eIF2α phosphatase dPPP1R15 impairs developmental BMP signalling in flies. In cells, inhibition of translation by GCN2 blocks downstream BMP signalling. Moreover, loss of d4E-BP, a target of crc, augments BMP signalling in vitro and rescues tissue development in vivo. Conclusion These results identify a novel mechanism by which the ISR modulates BMP signalling during development. Electronic supplementary material The online version of this article (10.1186/s12915-018-0503-x) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Elke Malzer
- Cambridge Institute for Medical Research (CIMR), University of Cambridge, Wellcome Trust/MRC Building, Hills Road, Cambridge, CB2 0XY, UK.,Department of Medicine, University of Cambridge, Addenbrooke's Hospital, Hills Rd, Cambridge, CB2 0SP, UK
| | - Caia S Dominicus
- Cambridge Institute for Medical Research (CIMR), University of Cambridge, Wellcome Trust/MRC Building, Hills Road, Cambridge, CB2 0XY, UK.,Department of Medicine, University of Cambridge, Addenbrooke's Hospital, Hills Rd, Cambridge, CB2 0SP, UK
| | - Joseph E Chambers
- Cambridge Institute for Medical Research (CIMR), University of Cambridge, Wellcome Trust/MRC Building, Hills Road, Cambridge, CB2 0XY, UK.,Department of Medicine, University of Cambridge, Addenbrooke's Hospital, Hills Rd, Cambridge, CB2 0SP, UK
| | - Jennifer A Dickens
- Cambridge Institute for Medical Research (CIMR), University of Cambridge, Wellcome Trust/MRC Building, Hills Road, Cambridge, CB2 0XY, UK.,Department of Medicine, University of Cambridge, Addenbrooke's Hospital, Hills Rd, Cambridge, CB2 0SP, UK
| | - Souradip Mookerjee
- Department of Medicine, University of Cambridge, Addenbrooke's Hospital, Hills Rd, Cambridge, CB2 0SP, UK
| | - Stefan J Marciniak
- Cambridge Institute for Medical Research (CIMR), University of Cambridge, Wellcome Trust/MRC Building, Hills Road, Cambridge, CB2 0XY, UK. .,Department of Medicine, University of Cambridge, Addenbrooke's Hospital, Hills Rd, Cambridge, CB2 0SP, UK.
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6
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Dickens JA, Ordóñez A, Chambers JE, Beckett AJ, Patel V, Malzer E, Dominicus CS, Bradley J, Peden AA, Prior IA, Lomas DA, Marciniak SJ. The endoplasmic reticulum remains functionally connected by vesicular transport after its fragmentation in cells expressing Z-α1-antitrypsin. FASEB J 2016; 30:4083-4097. [PMID: 27601439 PMCID: PMC5102109 DOI: 10.1096/fj.201600430r] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2016] [Accepted: 08/15/2016] [Indexed: 12/20/2022]
Abstract
α1-Antitrypsin is a serine protease inhibitor produced in the liver that is responsible for the regulation of pulmonary inflammation. The commonest pathogenic gene mutation yields Z-α1-antitrypsin, which has a propensity to self-associate forming polymers that become trapped in inclusions of endoplasmic reticulum (ER). It is unclear whether these inclusions are connected to the main ER network in Z-α1-antitrypsin-expressing cells. Using live cell imaging, we found that despite inclusions containing an immobile matrix of polymeric α1-antitrypsin, small ER resident proteins can diffuse freely within them. Inclusions have many features to suggest they represent fragmented ER, and some are physically separated from the tubular ER network, yet we observed cargo to be transported between them in a cytosol-dependent fashion that is sensitive to N-ethylmaleimide and dependent on Sar1 and sec22B. We conclude that protein recycling occurs between ER inclusions despite their physical separation.-Dickens, J. A., Ordóñez, A., Chambers, J. E., Beckett, A. J., Patel, V., Malzer, E., Dominicus, C. S., Bradley, J., Peden, A. A., Prior, I. A., Lomas, D. A., Marciniak, S. J. The endoplasmic reticulum remains functionally connected by vesicular transport after its fragmentation in cells expressing Z-α1-antitrypsin.
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Affiliation(s)
- Jennifer A Dickens
- Cambridge Institute for Medical Research, Cambridge, United Kingdom
- Department of Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Adriana Ordóñez
- Cambridge Institute for Medical Research, Cambridge, United Kingdom
| | - Joseph E Chambers
- Cambridge Institute for Medical Research, Cambridge, United Kingdom
- Department of Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Alison J Beckett
- Department of Biomedical Science, University of Sheffield, Sheffield, United Kingdom
| | - Vruti Patel
- Cambridge Institute for Medical Research, Cambridge, United Kingdom
| | - Elke Malzer
- Cambridge Institute for Medical Research, Cambridge, United Kingdom
| | - Caia S Dominicus
- Cambridge Institute for Medical Research, Cambridge, United Kingdom
| | - Jayson Bradley
- Cambridge Institute for Medical Research, Cambridge, United Kingdom
| | - Andrew A Peden
- Department of Biomedical Science, University of Sheffield, Sheffield, United Kingdom
| | - Ian A Prior
- Institute of Translational Medicine, University of Liverpool, Liverpool, United Kingdom; and
| | - David A Lomas
- UCL Respiratory, University College London, London, United Kingdom
| | - Stefan J Marciniak
- Cambridge Institute for Medical Research, Cambridge, United Kingdom;
- Department of Medicine, University of Cambridge, Cambridge, United Kingdom
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Malzer E, Dominicus CS, Marciniak SJ. S86 Understanding the role of GCN2 in modulating BMP signaling using drosophila – implications for pulmonary hypertension. Thorax 2016. [DOI: 10.1136/thoraxjnl-2016-209333.92] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Chambers JE, Dalton LE, Clarke HJ, Malzer E, Dominicus CS, Patel V, Moorhead G, Ron D, Marciniak SJ. Actin dynamics tune the integrated stress response by regulating eukaryotic initiation factor 2α dephosphorylation. eLife 2015; 4. [PMID: 25774599 PMCID: PMC4394351 DOI: 10.7554/elife.04872] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2014] [Accepted: 03/12/2015] [Indexed: 12/23/2022] Open
Abstract
Four stress-sensing kinases phosphorylate the alpha subunit of eukaryotic translation initiation factor 2 (eIF2α) to activate the integrated stress response (ISR). In animals, the ISR is antagonised by selective eIF2α phosphatases comprising a catalytic protein phosphatase 1 (PP1) subunit in complex with a PPP1R15-type regulatory subunit. An unbiased search for additional conserved components of the PPP1R15-PP1 phosphatase identified monomeric G-actin. Like PP1, G-actin associated with the functional core of PPP1R15 family members and G-actin depletion, by the marine toxin jasplakinolide, destabilised the endogenous PPP1R15A-PP1 complex. The abundance of the ternary PPP1R15-PP1-G-actin complex was responsive to global changes in the polymeric status of actin, as was its eIF2α-directed phosphatase activity, while localised G-actin depletion at sites enriched for PPP1R15 enhanced eIF2α phosphorylation and the downstream ISR. G-actin's role as a stabilizer of the PPP1R15-containing holophosphatase provides a mechanism for integrating signals regulating actin dynamics with stresses that trigger the ISR. DOI:http://dx.doi.org/10.7554/eLife.04872.001 For a cell to build a protein, it must first copy the instructions contained within a gene. A complex molecular machine called a ribosome then reads these instructions and translates them into a protein. This translation process involves a number of steps. Proteins called eukaryotic translation initiation factors (or eIFs for short) coordinate the first step in the process, which is known as ‘initiation’. The eIFs also provide the cell with ways to control how quickly it makes proteins. For example, when a cell is stressed, either by starvation or toxins, it adds a phosphate group onto part of an eIF protein, called eIF2α. This modification makes this eIF protein less able to initiate translation, and so the cell builds fewer proteins and conserves more of its resources during times of stress. Once the stressful conditions are over, the phosphate group is removed from eIF2α by an enzyme called a phosphatase. This phosphatase contains two subunits: one that recognizes eIF2α and another that removes the phosphate group. However, experiments that attempted to recreate this phosphatase activity using just these two subunits in a test tube failed to generate a working enzyme that specifically targeted the phosphate group of eIF2α. This suggests that in cells this enzyme contains an additional unknown subunit. Now, Chambers, Dalton et al. (and Chen et al.) report the identity of a ‘missing’ third subunit as a protein known as globular-actin or G-actin. Chambers, Dalton et al. engineered human and fruit fly cells to add ‘molecular handles’ on the two known subunits of the phosphatase enzyme. These handles could then be used to essentially pull these proteins out of the mixture of molecules within a cell and see what other proteins came along too. Both of the known subunits ‘pulled’ G-actin along with them; this suggested that it could be the missing part of the phosphatase enzyme. Further experiments confirmed that G-actin works together with the other two subunits to specifically remove the phosphate group from eIF2α in mouse cells that had been stressed using a harmful chemical. Individual G-actin proteins can bind together to form long filaments, and signals that encourage a cell to divide or move also trigger the formation of actin filaments. This reduces the activity of the phosphatase enzyme by depriving it of a crucial component, i.e., free G-actin proteins. As such, the new mechanism described by Chambers, Dalton et al. suggests how growth and movement signals might also change a cell's sensitivity to stress. These findings may hopefully enable stressed cells to be targeted by drugs to treat disease; but future work is needed to clarify under what circumstances the integration of such signals into the stress response is beneficial to the cell. DOI:http://dx.doi.org/10.7554/eLife.04872.002
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Affiliation(s)
- Joseph E Chambers
- Cambridge Institute for Medical Research, Department of Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Lucy E Dalton
- Cambridge Institute for Medical Research, Department of Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Hanna J Clarke
- Wellcome Trust MRC Building, University of Cambridge, Cambridge, United Kingdom
| | - Elke Malzer
- Cambridge Institute for Medical Research, Department of Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Caia S Dominicus
- Cambridge Institute for Medical Research, Department of Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Vruti Patel
- Cambridge Institute for Medical Research, Department of Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Greg Moorhead
- Department of Biological Sciences, University of Calgary, Calgary, Canada
| | - David Ron
- Wellcome Trust MRC Building, University of Cambridge, Cambridge, United Kingdom
| | - Stefan J Marciniak
- Wellcome Trust MRC Building, University of Cambridge, Cambridge, United Kingdom
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Roussel BD, Newton TM, Malzer E, Simecek N, Haq I, Thomas SE, Burr ML, Lehner PJ, Crowther DC, Marciniak SJ, Lomas DA. Sterol metabolism regulates neuroserpin polymer degradation in the absence of the unfolded protein response in the dementia FENIB. Hum Mol Genet 2013; 22:4616-26. [PMID: 23814041 PMCID: PMC3889810 DOI: 10.1093/hmg/ddt310] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2013] [Accepted: 06/26/2013] [Indexed: 12/19/2022] Open
Abstract
Mutants of neuroserpin are retained as polymers within the endoplasmic reticulum (ER) of neurones to cause the autosomal dominant dementia familial encephalopathy with neuroserpin inclusion bodies or FENIB. The cellular consequences are unusual in that the ordered polymers activate the ER overload response (EOR) in the absence of the canonical unfolded protein response. We use both cell lines and Drosophila models to show that the G392E mutant of neuroserpin that forms polymers is degraded by UBE2j1 E2 ligase and Hrd1 E3 ligase while truncated neuroserpin, a protein that lacks 132 amino acids, is degraded by UBE2g2 (E2) and gp78 (E3) ligases. The degradation of G392E neuroserpin results from SREBP-dependent activation of the cholesterol biosynthetic pathway in cells that express polymers of neuroserpin (G392E). Inhibition of HMGCoA reductase, the limiting enzyme of the cholesterol biosynthetic pathway, reduced the ubiquitination of G392E neuroserpin in our cell lines and increased the retention of neuroserpin polymers in both HeLa cells and primary neurones. Our data reveal a reciprocal relationship between cholesterol biosynthesis and the clearance of mutant neuroserpin. This represents the first description of a link between sterol metabolism and modulation of the proteotoxicity mediated by the EOR.
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Affiliation(s)
- Benoit D. Roussel
- Department of Medicine, University of Cambridge, Cambridge Institute for Medical Research (CIMR), Wellcome Trust/MRC Building, Hills Road, Cambridge CB2 0XY, UK
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10
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Thomas SE, Malzer E, Ordóñez A, Dalton LE, van T Wout EFA, Liniker E, Crowther DC, Lomas DA, Marciniak SJ. p53 and translation attenuation regulate distinct cell cycle checkpoints during endoplasmic reticulum (ER) stress. J Biol Chem 2013; 288:7606-7617. [PMID: 23341460 PMCID: PMC3597802 DOI: 10.1074/jbc.m112.424655] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2012] [Revised: 01/04/2013] [Indexed: 01/25/2023] Open
Abstract
Cell cycle checkpoints ensure that proliferation occurs only under permissive conditions, but their role in linking nutrient availability to cell division is incompletely understood. Protein folding within the endoplasmic reticulum (ER) is exquisitely sensitive to energy supply and amino acid sources because deficiencies impair luminal protein folding and consequently trigger ER stress signaling. Following ER stress, many cell types arrest within the G(1) phase, although recent studies have identified a novel ER stress G(2) checkpoint. Here, we report that ER stress affects cell cycle progression via two classes of signal: an early inhibition of protein synthesis leading to G(2) delay involving CHK1 and a later induction of G(1) arrest associated both with the induction of p53 target genes and loss of cyclin D(1). We show that substitution of p53/47 for p53 impairs the ER stress G(1) checkpoint, attenuates the recovery of protein translation, and impairs induction of NOXA, a mediator of cell death. We propose that cell cycle regulation in response to ER stress comprises redundant pathways invoked sequentially first to impair G(2) progression prior to ultimate G(1) arrest.
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Affiliation(s)
- Sally E Thomas
- Department of Medicine and Cambridge Institute for Medical Research, University of Cambridge, Wellcome Trust/Medical Research Council Building, Hills Road, Cambridge CB2 0XY, United Kingdom
| | - Elke Malzer
- Department of Medicine and Cambridge Institute for Medical Research, University of Cambridge, Wellcome Trust/Medical Research Council Building, Hills Road, Cambridge CB2 0XY, United Kingdom; Department of Genetics, University of Cambridge, Downing Site, Cambridge CB2 3EH, United Kingdom
| | - Adriana Ordóñez
- Department of Medicine and Cambridge Institute for Medical Research, University of Cambridge, Wellcome Trust/Medical Research Council Building, Hills Road, Cambridge CB2 0XY, United Kingdom
| | - Lucy E Dalton
- Department of Medicine and Cambridge Institute for Medical Research, University of Cambridge, Wellcome Trust/Medical Research Council Building, Hills Road, Cambridge CB2 0XY, United Kingdom
| | - Emily F A van T Wout
- Department of Medicine and Cambridge Institute for Medical Research, University of Cambridge, Wellcome Trust/Medical Research Council Building, Hills Road, Cambridge CB2 0XY, United Kingdom
| | - Elizabeth Liniker
- Department of Medicine and Cambridge Institute for Medical Research, University of Cambridge, Wellcome Trust/Medical Research Council Building, Hills Road, Cambridge CB2 0XY, United Kingdom
| | - Damian C Crowther
- Department of Genetics, University of Cambridge, Downing Site, Cambridge CB2 3EH, United Kingdom
| | - David A Lomas
- Department of Medicine and Cambridge Institute for Medical Research, University of Cambridge, Wellcome Trust/Medical Research Council Building, Hills Road, Cambridge CB2 0XY, United Kingdom
| | - Stefan J Marciniak
- Department of Medicine and Cambridge Institute for Medical Research, University of Cambridge, Wellcome Trust/Medical Research Council Building, Hills Road, Cambridge CB2 0XY, United Kingdom.
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11
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Malzer E, Szajewska-Skuta M, Dalton LE, Thomas SE, Hu N, Skaer H, Lomas DA, Crowther DC, Marciniak SJ. Coordinate regulation of eIF2α phosphorylation by PPP1R15 and GCN2 is required during Drosophila development. J Cell Sci 2013; 126:1406-15. [PMID: 23418347 DOI: 10.1242/jcs.117614] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Phosphorylation of eukaryotic translation initiation factor 2 alpha (eIF2α) by the kinase GCN2 attenuates protein synthesis during amino acid starvation in yeast, whereas in mammals a family of related eIF2α kinases regulate translation in response to a variety of stresses. Unlike single-celled eukaryotes, mammals also possess two specific eIF2α phosphatases, PPP1R15a and PPP1R15b, whose combined deletion leads to a poorly understood early embryonic lethality. We report the characterisation of the first non-mammalian eIF2α phosphatase and the use of Drosophila to dissect its role during development. The Drosophila protein demonstrates features of both mammalian proteins, including limited sequence homology and association with the endoplasmic reticulum. Of note, although this protein is not transcriptionally regulated, its expression is controlled by the presence of upstream open reading frames in its 5'UTR, enabling induction in response to eIF2α phosphorylation. Moreover, we show that its expression is necessary for embryonic and larval development and that this is to oppose the inhibitory effects of GCN2 on anabolic growth.
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Affiliation(s)
- Elke Malzer
- Department of Medicine, University of Cambridge, Cambridge Institute for Medical Research (CIMR), Wellcome Trust/MRC Building, Hills Road, Cambridge CB2 0XY, UK
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12
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Thomas SE, Dalton L, Malzer E, Marciniak SJ. Unravelling the story of protein misfolding in diabetes mellitus. World J Diabetes 2011; 2:114-8. [PMID: 21860696 PMCID: PMC3158865 DOI: 10.4239/wjd.v2.i7.114] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/15/2011] [Revised: 06/30/2011] [Accepted: 07/07/2011] [Indexed: 02/05/2023] Open
Abstract
Both environmental and genetic factors contribute to the development of diabetes mellitus and although monogenic disorders are rare, they offer unique insights into the fundamental biology underlying the disease. Mutations of the insulin gene or genes involved in the response to protein misfolding cause early onset diabetes. These have revealed an important role for endoplasmic reticulum stress in β-cell survival. This form of cellular stress occurs when secretory proteins fail to fold efficiently. Of all the professional secretory cells we possess, β-cells are the most sensitive to endoplasmic reticulum stress because of the large fluctuations in protein synthesis they face daily. Studies of endoplasmic reticulum stress signaling therefore offer the potential to identify new drug targets to treat diabetes.
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Affiliation(s)
- Sally E Thomas
- Sally E Thomas, Lucy Dalton, Elke Malzer, Stefan J Marciniak, Department of Medicine, University of Cambridge, Cambridge Institute for Medical Research, Wellcome Trust/MRC Building, Hills Road, Cambridge CB0 2XY, United Kingdom
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13
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Thomas SE, Dalton LE, Daly ML, Malzer E, Marciniak SJ. Diabetes as a disease of endoplasmic reticulum stress. Diabetes Metab Res Rev 2010; 26:611-21. [PMID: 20922715 DOI: 10.1002/dmrr.1132] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/21/2010] [Revised: 08/17/2010] [Accepted: 09/06/2010] [Indexed: 01/19/2023]
Abstract
Endoplasmic reticulum (ER) stress is an integral part of life for all professional secretory cells, but it has been studied to greatest depth in the pancreatic β-cell. This reflects both the crucial role played by ER stress in the pathogenesis of diabetes and also the exquisite vulnerability of these cells to ER dysfunction. The adaptive cellular response to ER stress, the unfolded protein response, comprises mechanisms to both regulate new protein translation and a transcriptional program to allow adaptation to the stress. The core of this response is a triad of stress-sensing proteins: protein kinase R-like endoplasmic reticulum kinase (PERK), inositol-requiring enzyme 1 (IRE1) and activating transcription factor 6. All three regulate portions of the transcriptional unfolded protein response, while PERK also attenuates protein synthesis during ER stress and IRE1 interacts directly with the c-Jun amino-terminal kinase stress kinase pathway. In this review we shall discuss these processes in detail, with emphasis given to their impact on diabetes and how recent findings indicate that ER stress may be responsible for the loss of β-cell mass in the disease.
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Affiliation(s)
- Sally E Thomas
- Department of Medicine, Cambridge Institute for Medical Research, University of Cambridge, Hills Road, Cambridge, UK
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14
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Malzer E, Daly ML, Moloney A, Sendall TJ, Thomas SE, Ryder E, Ryoo HD, Crowther DC, Lomas DA, Marciniak SJ. Impaired tissue growth is mediated by checkpoint kinase 1 (CHK1) in the integrated stress response. J Cell Sci 2010; 123:2892-900. [PMID: 20682638 DOI: 10.1242/jcs.070078] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The integrated stress response (ISR) protects cells from numerous forms of stress and is involved in the growth of solid tumours; however, it is unclear how the ISR acts on cellular proliferation. We have developed a model of ISR signalling with which to study its effects on tissue growth. Overexpression of the ISR kinase PERK resulted in a striking atrophic eye phenotype in Drosophila melanogaster that could be rescued by co-expressing the eIF2alpha phosphatase GADD34. A genetic screen of 3000 transposon insertions identified grapes, the gene that encodes the Drosophila orthologue of checkpoint kinase 1 (CHK1). Knockdown of grapes by RNAi rescued eye development despite ongoing PERK activation. In mammalian cells, CHK1 was activated by agents that induce ER stress, which resulted in a G2 cell cycle delay. PERK was both necessary and sufficient for CHK1 activation. These findings indicate that non-genotoxic misfolded protein stress accesses DNA-damage-induced cell cycle checkpoints to couple the ISR to cell cycle arrest.
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Affiliation(s)
- Elke Malzer
- Department of Medicine, University of Cambridge, Cambridge Institute for Medical Research (CIMR), Wellcome Trust/MRC Building, Hills Road, Cambridge, CB2 0XY, UK
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15
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Holtkamp N, Malzer E, Zietsch J, Okuducu AF, Mucha J, Mawrin C, Mautner VF, Schildhaus HU, von Deimling A. EGFR and erbB2 in malignant peripheral nerve sheath tumors and implications for targeted therapy. Neuro Oncol 2008; 10:946-57. [PMID: 18650488 DOI: 10.1215/15228517-2008-053] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Malignant peripheral nerve sheath tumors (MPNSTs) are sarcomas with poor prognosis and limited treatment options. Evidence for a role of epidermal growth factor receptor (EGFR) and receptor tyrosine kinase erbB2 in MPNSTs led us to systematically study these potential therapeutic targets in a larger tumor panel (n = 37). Multiplex ligation-dependent probe amplification and fluorescence in situ hybridization analysis revealed increased EGFR dosage in 28% of MPNSTs. ERBB2 and three tumor suppressor genes (PTEN [phosphatase and tensin homolog deleted on chromosome 10], CDKN2A [cyclin-dependent kinase inhibitor 2A], and TP53 [tumor protein p53]) were frequently lost or reduced. Reduction of CDKN2A was linked to appearance of metastasis. Comparison of corresponding neurofibromas and MPNSTs revealed an increase in genetic lesions in MPNSTs. No somatic mutations were found within tyrosine-kinase-encoding exons of EGFR and ERBB2. However, at the protein level, expression of EGFR and erbB2 was frequently detected in MPNSTs. EGFR expression was significantly associated with increased EGFR gene dosage. The EGFR ligands transforming growth factor alpha and EGF were more strongly expressed in MPNSTs than in neurofibromas. The effects of the drugs erlotinib and trastuzumab, which target EGFR and erbB2, were determined on MPNST cell lines. In contrast to trastuzumab, erlotinib mediated dose-dependent inhibition of cell proliferation. EGF-induced EGFR phosphorylation was attenuated by erlotinib. Summarized, our data indicate that EGFR and erbB2 are potential targets in treatment of MPNST patients.
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Affiliation(s)
- Nikola Holtkamp
- Institute of Neuropathology, Charité-Universitätsmedizin Berlin, CVK, Augustenburger Platz 1, D-13353 Berlin, Germany.
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16
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Vandrovcova J, Dunn L, Malzer E, Hardy J, Silva R. P2‐175: Tau gene‐specific natural antisense transcript expression and splicing in sporadic tauopathies. Alzheimers Dement 2008. [DOI: 10.1016/j.jalz.2008.05.1249] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Affiliation(s)
- Jana Vandrovcova
- Reta Lila Weston Institute of Neurological Studies, UCLLondonUnited Kingdom
| | - Laura Dunn
- Reta Lila Weston Institute of Neurological Studies, UCLLondonUnited Kingdom
| | - Elke Malzer
- Reta Lila Weston Institute of Neurological Studies, UCLLondonUnited Kingdom
| | - John Hardy
- Reta Lila Weston Institute of Neurological Studies, UCLLondonUnited Kingdom
| | - Rohan Silva
- Reta Lila Weston Institute of Neurological Studies, UCLLondonUnited Kingdom
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17
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Momeni P, Pittman A, Lashley T, Vandrovcova J, Malzer E, Luk C, Hulette C, Lees A, Revesz T, Hardy J, de Silva R. Clinical and pathological features of an Alzheimer's disease patient with the MAPT Delta K280 mutation. Neurobiol Aging 2007; 30:388-93. [PMID: 17723255 PMCID: PMC2666148 DOI: 10.1016/j.neurobiolaging.2007.07.013] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2007] [Revised: 07/03/2007] [Accepted: 07/18/2007] [Indexed: 10/22/2022]
Abstract
We identified a case of Alzheimer's disease with a deletion of the lysine residue at codon 280 (DeltaK280) in exon 10-encoded microtubule-binding repeat domain of the tau gene (MAPT). This mutation was originally identified in a sporadic case of frontotemporal dementia (FTD) with a family history of Parkinson's disease. In the original report, the authors were careful in their assessment of the pathogenicity and suggested one could not be sure whether the mutation was pathogenic or not. The mutation has always presented a conundrum because it is the only known mutation, of assumed pathogenicity, which increases the proportion of 3-repeat tau mRNA in in vitro assays. Here we present the clinical and pathological features of a new case with this mutation and discuss whether the mutation is indeed pathogenic.
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Affiliation(s)
- Parastoo Momeni
- Laboratory of Neurogenetics, NIA, Porter Neuroscience Building, NIH Main Campus, Bethesda, MD20892 USA
- Department of Neurology, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA
| | - Alan Pittman
- Reta Lila Weston Institute of Neurological Studies, London, WC1N 1PJ, UK
- Department of Molecular Neuroscience, UCL Institute of Neurology, London, WC1N 1PJ, UK
| | - Tammaryn Lashley
- Department of Molecular Neuroscience, UCL Institute of Neurology, London, WC1N 1PJ, UK
| | - Jana Vandrovcova
- Reta Lila Weston Institute of Neurological Studies, London, WC1N 1PJ, UK
- Department of Molecular Neuroscience, UCL Institute of Neurology, London, WC1N 1PJ, UK
| | - Elke Malzer
- Reta Lila Weston Institute of Neurological Studies, London, WC1N 1PJ, UK
- Department of Molecular Neuroscience, UCL Institute of Neurology, London, WC1N 1PJ, UK
| | - Connie Luk
- Reta Lila Weston Institute of Neurological Studies, London, WC1N 1PJ, UK
- Department of Molecular Neuroscience, UCL Institute of Neurology, London, WC1N 1PJ, UK
| | - Christine Hulette
- Departments of Neurology, Pathology, Neuropathology and Medicine, Duke University Medical Center, Durham, NC 27710, USA
| | - Andrew Lees
- Reta Lila Weston Institute of Neurological Studies, London, WC1N 1PJ, UK
| | - Tamas Revesz
- Department of Molecular Neuroscience, UCL Institute of Neurology, London, WC1N 1PJ, UK
| | - John Hardy
- Laboratory of Neurogenetics, NIA, Porter Neuroscience Building, NIH Main Campus, Bethesda, MD20892 USA
- Reta Lila Weston Institute of Neurological Studies, London, WC1N 1PJ, UK
- Department of Molecular Neuroscience, UCL Institute of Neurology, London, WC1N 1PJ, UK
| | - Rohan de Silva
- Reta Lila Weston Institute of Neurological Studies, London, WC1N 1PJ, UK
- Department of Molecular Neuroscience, UCL Institute of Neurology, London, WC1N 1PJ, UK
- Correspondence: Dr Rohan de Silva, Reta Lila Weston Institute of Neurological Studies, 1 Wakefield Street, London, WC1N 1PJ, U. K. , Fax: +44-20-7278 4993
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18
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Holtkamp N, Ziegenhagen N, Malzer E, Hartmann C, Giese A, von Deimling A. Characterization of the amplicon on chromosomal segment 4q12 in glioblastoma multiforme. Neuro Oncol 2007; 9:291-7. [PMID: 17504929 PMCID: PMC1907422 DOI: 10.1215/15228517-2007-009] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
A subset of glioblastomas (GBMs) carry gene amplifications on chromosomal segment 4q12. To characterize this amplicon in detail, we analyzed a set of 100 samples consisting of 65 GBMs, 10 WHO grade III astrocytomas, 12 oligodendrogliomas, and 13 glioma cell cultures. We applied multiplex ligation-dependent probe amplification to determine the gene dosage of PDGFRA, KIT, and KDR and the flanking genes USP46, RASL11B, LNX1, CHIC2, SEC3L1, and IGFBP7. The amplicon was highly variable in size and copy number and extended over a region of up to 5 Mb. Amplifications on 4q12 were observed in 15% of GBMs and 23% of GBM cell cultures but not in 22 other gliomas. We analyzed transcription and translation of some genes within this amplicon. Gene amplification generally correlated with high transcript levels but did not necessarily result in increased protein levels. However, we detected frequent expression of proteins encoded by PDGFRA, KIT, and KDR in GBMs and GBM cell cultures independent of the amplification status. Future treatment of GBM patients may include drugs targeting multiple kinases that are encoded by genes on chromosomal segment 4q12.
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Affiliation(s)
| | | | | | | | | | - Andreas von Deimling
- Address correspondence to Andreas von Deimling, Department of Neuropathology, Ruprecht-Karls-Universität, Im Neuenheimer Feld 220, 69120 Heidelberg, Germany (
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