1
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Bettadj FZY, Benchouk W. Computer-aided analysis for identification of novel analogues of ketoprofen based on molecular docking, ADMET, drug-likeness and DFT studies for the treatment of inflammation. J Biomol Struct Dyn 2023; 41:9915-9930. [PMID: 36444967 DOI: 10.1080/07391102.2022.2148750] [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: 08/11/2022] [Accepted: 11/12/2022] [Indexed: 11/30/2022]
Abstract
Computer-based drug design is increasingly used in strategies for discovering new molecules for therapeutic purposes. The targeted drug is ketoprofen (KTP), which belongs to the family of non-steroidal anti-inflammatory drugs, which are widely used for the treatment of pain, fever, inflammation and certain types of cancers. In an attempt to rationalize the search for 72 new potential anti-inflammatory compounds on the COX-2 enzyme, we carried out an in silico protocol that successfully combines molecular docking towards COX-2 receptor (5F1A), ADMET pharmacokinetic parameters, drug-likeness rules and molecular electrostatic potential (MEP). It was found that six of the compounds analyzed satisfy with the associated values to physico-chemical properties as key evaluation parameters for the drug-likeness and demonstrate a hydrophobic character which makes their solubility in aqueous media difficult and easy in lipids. All the compounds presented good ADMET profile and they showed an interaction with the amino acids responsible for anti-inflammatory activity of the COX-2 isoenzyme. The calculation of the MEP of the six analogues reveals new preferential sites involving the formation of new bonds. Consequently, this result allowed us to understand the origin of the potential increase in the anti-inflammatory activity of the candidates. Finally, it was obtained that six compounds have a binding mode, binding energy, and stability in the active site of COX-2 like the reference drug ketoprofen, suggesting that these compounds could become a powerful candidate in the inhibition of the COX-2 enzyme.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Fatima Zohra Yasmine Bettadj
- Laboratory of Applied Thermodynamics and Molecular Modeling, Department of Chemistry, Faculty of Science, University of Tlemcen, Tlemcen, Algeria
| | - Wafaa Benchouk
- Laboratory of Applied Thermodynamics and Molecular Modeling, Department of Chemistry, Faculty of Science, University of Tlemcen, Tlemcen, Algeria
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2
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Jilderda LJ, Zhou L, Foijer F. Understanding How Genetic Mutations Collaborate with Genomic Instability in Cancer. Cells 2021; 10:342. [PMID: 33562057 PMCID: PMC7914657 DOI: 10.3390/cells10020342] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2020] [Revised: 01/25/2021] [Accepted: 02/03/2021] [Indexed: 01/23/2023] Open
Abstract
Chromosomal instability is the process of mis-segregation for ongoing chromosomes, which leads to cells with an abnormal number of chromosomes, also known as an aneuploid state. Induced aneuploidy is detrimental during development and in primary cells but aneuploidy is also a hallmark of cancer cells. It is therefore believed that premalignant cells need to overcome aneuploidy-imposed stresses to become tumorigenic. Over the past decade, some aneuploidy-tolerating pathways have been identified through small-scale screens, which suggest that aneuploidy tolerance pathways can potentially be therapeutically exploited. However, to better understand the processes that lead to aneuploidy tolerance in cancer cells, large-scale and unbiased genetic screens are needed, both in euploid and aneuploid cancer models. In this review, we describe some of the currently known aneuploidy-tolerating hits, how large-scale genome-wide screens can broaden our knowledge on aneuploidy specific cancer driver genes, and how we can exploit the outcomes of these screens to improve future cancer therapy.
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Affiliation(s)
| | | | - Floris Foijer
- European Research Institute for the Biology of Ageing (ERIBA), University of Groningen, University Medical Centre Groningen, 9713 AV Groningen, The Netherlands; (L.J.J.); (L.Z.)
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3
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HRAS, EGFR, MET, and RON Genes Are Recurrently Activated by Provirus Insertion in Liver Tumors Induced by the Retrovirus Myeloblastosis-Associated Virus 2. J Virol 2017; 91:JVI.00467-17. [PMID: 28768863 DOI: 10.1128/jvi.00467-17] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2017] [Accepted: 07/14/2017] [Indexed: 12/28/2022] Open
Abstract
Myeloblastosis-associated virus 2 (MAV-2) is a highly tumorigenic simple avian retrovirus. Chickens infected in ovo with MAV-2 develop tumors in the kidneys, lungs, and liver with a short latency, less than 8 weeks. Here we report the results of molecular analyses of MAV-2-induced liver tumors that fall into three classes: hepatic hemangiosarcomas (HHSs), intrahepatic cholangiocarcinomas (ICCs), and hepatocellular carcinomas (HCCs). Comprehensive inverse PCR-based screening of 92 chicken liver tumors revealed that in ca. 86% of these tumors, MAV-2 provirus had integrated into one of four gene loci: HRAS, EGFR, MET, and RON Insertionally mutated genes correlated with tumor type: HRAS was hit in HHSs, MET in ICCs, RON mostly in ICCs, and EGFR mostly in HCCs. The provirus insertions led to the overexpression of the affected genes and, in the case of EGFR and RON, also to the truncation of exons encoding the extracellular ligand-binding domains of these transmembrane receptors. The structures of truncated EGFR and RON closely mimic the structures of oncogenic variants of these genes frequently found in human tumors (EGFRvIII and sfRON).IMPORTANCE These data describe the mechanisms of oncogenesis induced in chickens by the MAV-2 retrovirus. They also show that molecular processes converting cellular regulatory genes to cancer genes may be remarkably similar in chickens and humans. We suggest that the MAV-2 retrovirus-based model can complement experiments performed using mouse models and provide data that could translate to human medicine.
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4
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Cesana D, Santoni de Sio FR, Rudilosso L, Gallina P, Calabria A, Beretta S, Merelli I, Bruzzesi E, Passerini L, Nozza S, Vicenzi E, Poli G, Gregori S, Tambussi G, Montini E. HIV-1-mediated insertional activation of STAT5B and BACH2 trigger viral reservoir in T regulatory cells. Nat Commun 2017; 8:498. [PMID: 28887441 PMCID: PMC5591266 DOI: 10.1038/s41467-017-00609-1] [Citation(s) in RCA: 70] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2016] [Accepted: 07/12/2017] [Indexed: 12/13/2022] Open
Abstract
HIV-1 insertions targeting BACH2 or MLK2 are enriched and persist for decades in hematopoietic cells from patients under combination antiretroviral therapy. However, it is unclear how these insertions provide such selective advantage to infected cell clones. Here, we show that in 30/87 (34%) patients under combination antiretroviral therapy, BACH2, and STAT5B are activated by insertions triggering the formation of mRNAs that contain viral sequences fused by splicing to their first protein-coding exon. These chimeric mRNAs, predicted to express full-length proteins, are enriched in T regulatory and T central memory cells, but not in other T lymphocyte subsets or monocytes. Overexpression of BACH2 or STAT5B in primary T regulatory cells increases their proliferation and survival without compromising their function. Hence, we provide evidence that HIV-1-mediated insertional activation of BACH2 and STAT5B favor the persistence of a viral reservoir in T regulatory cells in patients under combination antiretroviral therapy. HIV insertions in hematopoietic cells are enriched in BACH2 or MLK2 genes, but the selective advantages conferred are unknown. Here, the authors show that BACH2 and additionally STAT5B are activated by viral insertions, generating chimeric mRNAs specifically enriched in T regulatory cells favoring their persistence.
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Affiliation(s)
- Daniela Cesana
- San Raffaele Telethon Institute for Gene Therapy (SR-Tiget), IRCCS, San Raffaele Scientific Institute, Milan, 20132, Italy.
| | - Francesca R Santoni de Sio
- San Raffaele Telethon Institute for Gene Therapy (SR-Tiget), IRCCS, San Raffaele Scientific Institute, Milan, 20132, Italy
| | - Laura Rudilosso
- San Raffaele Telethon Institute for Gene Therapy (SR-Tiget), IRCCS, San Raffaele Scientific Institute, Milan, 20132, Italy
| | - Pierangela Gallina
- San Raffaele Telethon Institute for Gene Therapy (SR-Tiget), IRCCS, San Raffaele Scientific Institute, Milan, 20132, Italy
| | - Andrea Calabria
- San Raffaele Telethon Institute for Gene Therapy (SR-Tiget), IRCCS, San Raffaele Scientific Institute, Milan, 20132, Italy
| | - Stefano Beretta
- Department of Informatics, Systems and Communication, University of Milano-Bicocca, Viale Sarca 336, Milan, 20126, Italy.,National Research Council, Institute for Biomedical Technologies, Via Fratelli Cervi 93, Segrate, 20090, Italy
| | - Ivan Merelli
- National Research Council, Institute for Biomedical Technologies, Via Fratelli Cervi 93, Segrate, 20090, Italy
| | - Elena Bruzzesi
- Department of Infectious Diseases, IRCCS, San Raffaele Scientific Institute, Milan, 20132, Italy
| | - Laura Passerini
- San Raffaele Telethon Institute for Gene Therapy (SR-Tiget), IRCCS, San Raffaele Scientific Institute, Milan, 20132, Italy
| | - Silvia Nozza
- Department of Infectious Diseases, IRCCS, San Raffaele Scientific Institute, Milan, 20132, Italy
| | - Elisa Vicenzi
- Viral Pathogens and Biosafety Unit, Division of Immunology, Transplantation and Infectious Diseases, IRCCS, San Raffaele Scientific Institute, Milan, 20132, Italy
| | - Guido Poli
- AIDS Immunopathogenesis Unit, Division of Immunology, Transplantation and Infectious Diseases, IRCCS, San Raffaele Scientific Institute, Milan, 20132, Italy.,Vita-Salute San Raffaele University School of Medicine, Milan, 20132, Italy
| | - Silvia Gregori
- San Raffaele Telethon Institute for Gene Therapy (SR-Tiget), IRCCS, San Raffaele Scientific Institute, Milan, 20132, Italy
| | - Giuseppe Tambussi
- Department of Infectious Diseases, IRCCS, San Raffaele Scientific Institute, Milan, 20132, Italy
| | - Eugenio Montini
- San Raffaele Telethon Institute for Gene Therapy (SR-Tiget), IRCCS, San Raffaele Scientific Institute, Milan, 20132, Italy.
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5
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Kawakami K, Largaespada DA, Ivics Z. Transposons As Tools for Functional Genomics in Vertebrate Models. Trends Genet 2017; 33:784-801. [PMID: 28888423 DOI: 10.1016/j.tig.2017.07.006] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Revised: 07/14/2017] [Accepted: 07/18/2017] [Indexed: 02/06/2023]
Abstract
Genetic tools and mutagenesis strategies based on transposable elements are currently under development with a vision to link primary DNA sequence information to gene functions in vertebrate models. By virtue of their inherent capacity to insert into DNA, transposons can be developed into powerful tools for chromosomal manipulations. Transposon-based forward mutagenesis screens have numerous advantages including high throughput, easy identification of mutated alleles, and providing insight into genetic networks and pathways based on phenotypes. For example, the Sleeping Beauty transposon has become highly instrumental to induce tumors in experimental animals in a tissue-specific manner with the aim of uncovering the genetic basis of diverse cancers. Here, we describe a battery of mutagenic cassettes that can be applied in conjunction with transposon vectors to mutagenize genes, and highlight versatile experimental strategies for the generation of engineered chromosomes for loss-of-function as well as gain-of-function mutagenesis for functional gene annotation in vertebrate models, including zebrafish, mice, and rats.
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Affiliation(s)
- Koichi Kawakami
- Division of Molecular and Developmental Biology, National Institute of Genetics, Mishima, Japan; These authors contributed equally to this work
| | - David A Largaespada
- Department of Genetics, Cell Biology and Development, University of Minnesota, MN, USA; These authors contributed equally to this work
| | - Zoltán Ivics
- Division of Medical Biotechnology, Paul Ehrlich Institute, Langen, Germany; These authors contributed equally to this work..
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6
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Kizilors A, Pickard MR, Schulte CE, Yacqub-Usman K, McCarthy NJ, Gan SU, Darling D, Gäken J, Williams GT, Farzaneh F. Retroviral insertional mutagenesis implicates E3 ubiquitin ligase RNF168 in the control of cell proliferation and survival. Biosci Rep 2017; 37:BSR20170843. [PMID: 28754805 PMCID: PMC5634340 DOI: 10.1042/bsr20170843] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2017] [Revised: 07/11/2017] [Accepted: 07/27/2017] [Indexed: 02/01/2023] Open
Abstract
The E3 ubiquitin ligase RNF168 is a ring finger protein that has previously been identified to play an important regulatory role in the repair of double-strand DNA breaks. In the present study, an unbiased forward genetics functional screen in mouse granulocyte/ macrophage progenitor cell line FDCP1 has identified E3 ubiquitin ligase RNF168 as a key regulator of cell survival and proliferation. Our data indicate that RNF168 is an important component of the mechanisms controlling cell fate, not only in human and mouse haematopoietic growth factor-dependent cells, but also in the human breast epithelial cell line MCF-7. These observations therefore suggest that RNF168 provides a connection to key pathways controlling cell fate, potentially through interaction with PML nuclear bodies and/or epigenetic control of gene expression. Our study is the first to demonstrate a critical role for RNF168 in the in the mechanisms regulating cell proliferation and survival, in addition to its well-established role in DNA repair.
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Affiliation(s)
| | | | | | | | | | - Shu-Uin Gan
- King's College London, London, N/A, United Kingdom
| | | | - Joop Gäken
- King's College London, London, N/A, United Kingdom
| | - Gwyn T Williams
- Life Sciences, Keele University, Keele, N/A, AT5 5AZ, United Kingdom
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7
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Ikink GJ, Boer M, Bakker ERM, Hilkens J. IRS4 induces mammary tumorigenesis and confers resistance to HER2-targeted therapy through constitutive PI3K/AKT-pathway hyperactivation. Nat Commun 2016; 7:13567. [PMID: 27876799 PMCID: PMC5122961 DOI: 10.1038/ncomms13567] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2015] [Accepted: 10/14/2016] [Indexed: 02/06/2023] Open
Abstract
In search of oncogenic drivers and mechanisms affecting therapy resistance in breast cancer, we identified Irs4, a poorly studied member of the insulin receptor substrate (IRS) family, as a mammary oncogene by insertional mutagenesis. Whereas normally silent in the postnatal mammary gland, IRS4 is found to be highly expressed in a subset of breast cancers. We show that Irs4 expression in mammary epithelial cells induces constitutive PI3K/AKT pathway hyperactivation, insulin/IGF1-independent cell proliferation, anchorage-independent growth and in vivo tumorigenesis. The constitutive PI3K/AKT pathway hyperactivation by IRS4 is unique to the IRS family and we identify the lack of a SHP2-binding domain in IRS4 as the molecular basis of this feature. Finally, we show that IRS4 and ERBB2/HER2 synergistically induce tumorigenesis and that IRS4-expression confers resistance to HER2-targeted therapy. Taken together, our findings present the cellular and molecular mechanisms of IRS4-induced tumorigenesis and establish IRS4 as an oncogenic driver and biomarker for therapy resistance in breast cancer. IRS proteins are scaffolds that can activate survival signalling pathways. In this study, the authors identified IRS4 as a potential oncogene in breast cancer that leads to the constitutive activation of PI3K/AKT signalling and thus confers resistance to HER2-targeted therapy.
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Affiliation(s)
- Gerjon J Ikink
- Division of Molecular Genetics, The Netherlands Cancer Institute, Plesmanlaan 121, CX 1066 Amsterdam, The Netherlands
| | - Mandy Boer
- Division of Molecular Genetics, The Netherlands Cancer Institute, Plesmanlaan 121, CX 1066 Amsterdam, The Netherlands
| | - Elvira R M Bakker
- Division of Molecular Genetics, The Netherlands Cancer Institute, Plesmanlaan 121, CX 1066 Amsterdam, The Netherlands
| | - John Hilkens
- Division of Molecular Genetics, The Netherlands Cancer Institute, Plesmanlaan 121, CX 1066 Amsterdam, The Netherlands
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8
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Propagation of trimethylated H3K27 regulated by polycomb protein EED is required for embryogenesis, hematopoietic maintenance, and tumor suppression. Proc Natl Acad Sci U S A 2016; 113:10370-5. [PMID: 27578866 DOI: 10.1073/pnas.1600070113] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Polycomb repressive complex 2 (PRC2) catalyzes the monomethylation, dimethylation, and trimethylation of histone H3 Lys27 (H3K27) and acts as a central epigenetic regulator that marks the repressive chromatin domain. Embryonic ectoderm development (EED), an essential component of PRC2, interacts with trimethylated H3K27 (H3K27me3) through the aromatic cage structure composed of its three aromatic amino acids, Phe97, Trp364, and Tyr365. This interaction allosterically activates the histone methyltransferase activity of PRC2 and thereby propagates repressive histone marks. In this study, we report the analysis of knock-in mice harboring the myeloid disorder-associated EED Ile363Met (I363M) mutation, analogous to the EED aromatic cage mutants. The I363M homozygotes displayed a remarkable and preferential reduction of H3K27me3 and died at midgestation. The heterozygotes increased the clonogenic capacity and bone marrow repopulating activity of hematopoietic stem/progenitor cells (HSPCs) and were susceptible to leukemia. Lgals3, a PRC2 target gene encoding a multifunctional galactose-binding lectin, was derepressed in I363M heterozygotes, which enhanced the stemness of HSPCs. Thus, our work provides in vivo evidence that the structural integrity of EED to H3K27me3 propagation is critical, especially for embryonic development and hematopoietic homeostasis, and that its perturbation increases the predisposition to hematologic malignancies.
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9
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Abstract
The MYC proto-oncogene is an essential regulator of many normal biological programmes. MYC, when activated as an oncogene, has been implicated in the pathogenesis of most types of human cancers. MYC overexpression in normal cells is restrained from causing cancer through multiple genetically and epigenetically controlled checkpoint mechanisms, including proliferative arrest, apoptosis and cellular senescence. When pathologically activated in the correct epigenetic and genetic contexts, MYC bypasses these mechanisms and drives many of the 'hallmark' features of cancer, including uncontrolled tumour growth associated with DNA replication and transcription, cellular proliferation and growth, protein synthesis and altered cellular metabolism. MYC also dictates tumour cell fate by enforcing self-renewal and by abrogating cellular senescence and differentiation programmes. Moreover, MYC influences the tumour microenvironment, including activating angiogenesis and suppressing the host immune response. Provocatively, brief or even partial suppression of MYC back to its physiological levels of activation can lead to the restoration of intrinsic checkpoint mechanisms, resulting in acute and sustained tumour regression associated with tumour cells undergoing proliferative arrest, differentiation, senescence and apoptosis, as well as remodelling of the tumour microenvironment, recruitment of an immune response and shutdown of angiogenesis. Hence, tumours appear to be addicted to the MYC oncogene because of both tumour cell intrinsic and host-dependent mechanisms. MYC is important for the regulation of both the initiation and maintenance of tumorigenesis.
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Affiliation(s)
- Y Li
- Division of Oncology, Departments of Medicine and Pathology, Stanford University School of Medicine, Stanford, CA, USA
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10
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Gabay M, Li Y, Felsher DW. MYC activation is a hallmark of cancer initiation and maintenance. Cold Spring Harb Perspect Med 2014; 4:4/6/a014241. [PMID: 24890832 DOI: 10.1101/cshperspect.a014241] [Citation(s) in RCA: 577] [Impact Index Per Article: 57.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The MYC proto-oncogene has been implicated in the pathogenesis of most types of human tumors. MYC activation alone in many normal cells is restrained from causing tumorigenesis through multiple genetic and epigenetically controlled checkpoint mechanisms, including proliferative arrest, apoptosis, and cellular senescence. When pathologically activated in a permissive epigenetic and/or genetic context, MYC bypasses these mechanisms, enforcing many of the "hallmark" features of cancer, including relentless tumor growth associated with DNA replication and transcription, cellular proliferation and growth, protein synthesis, and altered cellular metabolism. MYC mandates tumor cell fate, by inducing stemness and blocking cellular senescence and differentiation. Additionally, MYC orchestrates changes in the tumor microenvironment, including the activation of angiogenesis and suppression of the host immune response. Provocatively, brief or even partial suppression of MYC back to its physiological levels of activation can result in the restoration of intrinsic checkpoint mechanisms, resulting in acute and sustained tumor regression, associated with tumor cells undergoing proliferative arrest, differentiation, senescence, and apoptosis, as well as remodeling of the tumor microenvironment, recruitment of an immune response, and shutdown of angiogenesis. Hence, tumors appear to be "addicted" to MYC because of both tumor cell-intrinsic, cell-autonomous and host-dependent, immune cell-dependent mechanisms. Both the trajectory and persistence of many human cancers require sustained MYC activation. Multiscale mathematical modeling may be useful to predict when tumors will be addicted to MYC. MYC is a hallmark molecular feature of both the initiation and maintenance of tumorigenesis.
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Affiliation(s)
- Meital Gabay
- Division of Oncology, Departments of Medicine and Pathology, Stanford University School of Medicine, Stanford, California 94305
| | - Yulin Li
- Division of Oncology, Departments of Medicine and Pathology, Stanford University School of Medicine, Stanford, California 94305
| | - Dean W Felsher
- Division of Oncology, Departments of Medicine and Pathology, Stanford University School of Medicine, Stanford, California 94305
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11
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Hackett PB, Largaespada DA, Switzer KC, Cooper LJN. Evaluating risks of insertional mutagenesis by DNA transposons in gene therapy. Transl Res 2013; 161:265-83. [PMID: 23313630 PMCID: PMC3602164 DOI: 10.1016/j.trsl.2012.12.005] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/30/2012] [Revised: 12/10/2012] [Accepted: 12/11/2012] [Indexed: 12/30/2022]
Abstract
Investigational therapy can be successfully undertaken using viral- and nonviral-mediated ex vivo gene transfer. Indeed, recent clinical trials have established the potential for genetically modified T cells to improve and restore health. Recently, the Sleeping Beauty (SB) transposon/transposase system has been applied in clinical trials to stably insert a chimeric antigen receptor (CAR) to redirect T-cell specificity. We discuss the context in which the SB system can be harnessed for gene therapy and describe the human application of SB-modified CAR(+) T cells. We have focused on theoretical issues relating to insertional mutagenesis in the context of human genomes that are naturally subjected to remobilization of transposons and the experimental evidence over the last decade of employing SB transposons for defining genes that induce cancer. These findings are put into the context of the use of SB transposons in the treatment of human disease.
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Affiliation(s)
- Perry B Hackett
- Department of Genetics Cell Biology and Development, Center for Genome Engineering and Masonic Cancer Center, University of Minnesota, Minneapolis, MN 55455, USA.
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12
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Moriarity B, Largaespada DA. A Comprehensive Guide to Sleeping Beauty-Based Somatic Transposon Mutagenesis in the Mouse. ACTA ACUST UNITED AC 2011; 1:347-68. [PMID: 26069058 DOI: 10.1002/9780470942390.mo110087] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Recent advances in whole genome analyses made possible by next-generation DNA sequencing, high-density array comparative genome hybridization (aCGH), and other technologies have made it apparent that cancers harbor numerous genomic changes. However, without functional correlation or validation, it has proven difficult to determine which genetic changes are necessary or sufficient to produce cancer. Thus, it is still necessary to perform unbiased functional studies using model organisms to help interpret the results of whole genome analyses of human tumors. To this end, a Sleeping Beauty (SB) transposon-based mutagenesis technology was developed to identify genes that, when mutated, can cause cancer. Herein a detailed methodology to initiate and carry out an SB transposon mutagenesis screen is described. Although this system might be used to identify genes involved with many cellular phenotypes, it has been primarily implemented for cancer. Thus, SB transposon somatic cell screens for cancer development are highlighted. Curr. Protoc. Mouse Biol. 1:347-368 © 2011 by John Wiley & Sons, Inc.
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Affiliation(s)
- Branden Moriarity
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, Minnesota.,Center for Genome Engineering, University of Minnesota, Minneapolis, Minnesota.,Masonic Cancer Center, University of Minnesota, Minneapolis, Minnesota
| | - David A Largaespada
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, Minnesota.,Center for Genome Engineering, University of Minnesota, Minneapolis, Minnesota.,Masonic Cancer Center, University of Minnesota, Minneapolis, Minnesota
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13
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Landrette SF, Xu T. Somatic genetics empowers the mouse for modeling and interrogating developmental and disease processes. PLoS Genet 2011; 7:e1002110. [PMID: 21814514 PMCID: PMC3140981 DOI: 10.1371/journal.pgen.1002110] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
With recent advances in genomic technologies, candidate human disease genes are being mapped at an accelerated pace. There is a clear need to move forward with genetic tools that can efficiently validate these mutations in vivo. Murine somatic mutagenesis is evolving to fulfill these needs with tools such as somatic transgenesis, humanized rodents, and forward genetics. By combining these resources one is not only able to model disease for in vivo verification, but also to screen for mutations and pathways integral to disease progression and therapeutic intervention. In this review, we briefly outline the current advances in somatic mutagenesis and discuss how these new tools, especially the piggyBac transposon system, can be applied to decipher human biology and disease.
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Affiliation(s)
- Sean F. Landrette
- Department of Genetics, Howard Hughes Medical Institute, Yale University School of Medicine, Boyer Center for Molecular Medicine, New Haven, Connecticut, United States of America
| | - Tian Xu
- Department of Genetics, Howard Hughes Medical Institute, Yale University School of Medicine, Boyer Center for Molecular Medicine, New Haven, Connecticut, United States of America
- Institute of Developmental Biology and Molecular Medicine, Fudan-Yale Center for Biomedical Research, School of Life Science, Fudan University, Shanghai, China
- * E-mail:
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14
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Dettman E, Simko SJ, Ayanga B, Carofino B, Margolin J, Morse HC, Justice MJ. Prdm14 initiates lymphoblastic leukemia after expanding a population of cells resembling common lymphoid progenitors. Oncogene 2011; 30:2859-73. [PMID: 21339739 PMCID: PMC3121925 DOI: 10.1038/onc.2011.12] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2010] [Revised: 11/23/2010] [Accepted: 01/06/2011] [Indexed: 12/17/2022]
Abstract
Understanding the heterogeneous genetic mechanisms of tumor initiation in lymphoid leukemias (LL) will lead to improvements in prognostic classification and treatment regimens. In previous studies of mouse leukemias, we showed that retroviral insertion at the ecotropic viral insertion site 32 locus leads to increased expression of Prdm14, a pluripotency gene implicated in the self-renewal capacity of embryonic stem cells and the early stages of breast cancer. Here, we show that PRDM14 is also overexpressed in ∼25% of human lymphoid neoplasms, with increased frequencies in T-cell acute LL and hyperdiploid precursor B-cell acute LL. To test if Prdm14 overexpression could initiate leukemia, mice were transduced with bone marrow cells transfected with a Prdm14 expression vector. LLs developed in 96% of female mice and 42% of male mice. Before the onset of leukemia, differentiation of transduced cells was biased up to 1000-fold toward cells with features of common lymphoid progenitors (CLPs), and lymphoid differentiation showed a relative block at the pro-B stage. Microarray gene expression analysis of expanded CLP-like cells before the onset of leukemia demonstrated upregulation of genes involved in pluripotency, tumor initiation, early B-lineage commitment, Wnt/Ras signaling and the epithelial-to-mesenchymal transition. Among the dysregulated genes were imprinted genes and non-coding RNAs including Dlk1 and Meg3, which are also key pluripotency mediators. Heightened expression of the estrogen-dependent oncogene, Myb, in tumors suggests a basis for the increased frequency of cancer in female mice. These data provide the first direct evidence for the association of Prdm14 with cancer initiation in an in vivo mouse model and in human lymphoid malignancies, while suggesting mechanisms for Prdm14's mode of action.
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Affiliation(s)
- E.J. Dettman
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
| | - Stephen J. Simko
- Department of Pediatrics, Section of Hematology and Oncology, Baylor College of Medicine, Houston, Texas
| | - Bernard Ayanga
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
| | - Brandi Carofino
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
| | - Judith Margolin
- Department of Pediatrics, Section of Hematology and Oncology, Baylor College of Medicine, Houston, Texas
| | - Herbert C. Morse
- Laboratory of Immunopathology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland
| | - Monica J. Justice
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, Texas
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15
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de Jong J, de Ridder J, van der Weyden L, Sun N, van Uitert M, Berns A, van Lohuizen M, Jonkers J, Adams DJ, Wessels LFA. Computational identification of insertional mutagenesis targets for cancer gene discovery. Nucleic Acids Res 2011; 39:e105. [PMID: 21652642 PMCID: PMC3159484 DOI: 10.1093/nar/gkr447] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Insertional mutagenesis is a potent forward genetic screening technique used to identify candidate cancer genes in mouse model systems. An important, yet unresolved issue in the analysis of these screens, is the identification of the genes affected by the insertions. To address this, we developed Kernel Convolved Rule Based Mapping (KC-RBM). KC-RBM exploits distance, orientation and insertion density across tumors to automatically map integration sites to target genes. We perform the first genome-wide evaluation of the association of insertion occurrences with aberrant gene expression of the predicted targets in both retroviral and transposon data sets. We demonstrate the efficiency of KC-RBM by showing its superior performance over existing approaches in recovering true positives from a list of independently, manually curated cancer genes. The results of this work will significantly enhance the accuracy and speed of cancer gene discovery in forward genetic screens. KC-RBM is available as R-package.
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Affiliation(s)
- Johann de Jong
- Bioinformatics and Statistics, The Netherlands Cancer Institute, Plesmanlaan 121, 1066CX Amsterdam, The Netherlands
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16
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Rutkowski DT, Hegde RS. Regulation of basal cellular physiology by the homeostatic unfolded protein response. ACTA ACUST UNITED AC 2010; 189:783-94. [PMID: 20513765 PMCID: PMC2878945 DOI: 10.1083/jcb.201003138] [Citation(s) in RCA: 299] [Impact Index Per Article: 21.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The extensive membrane network of the endoplasmic reticulum (ER) is physically juxtaposed to and functionally entwined with essentially all other cellular compartments. Therefore, the ER must sense diverse and constantly changing physiological inputs so it can adjust its numerous functions to maintain cellular homeostasis. A growing body of new work suggests that the unfolded protein response (UPR), traditionally charged with signaling protein misfolding stress from the ER, has been co-opted for the maintenance of basal cellular homeostasis. Thus, the UPR can be activated, and its output modulated, by signals far outside the realm of protein misfolding. These findings are revealing that the UPR causally contributes to disease not just by its role in protein folding but also through its broad influence on cellular physiology.
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Affiliation(s)
- D Thomas Rutkowski
- Department of Anatomy and Cell Biology, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA.
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17
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Mendrysa SM, Akagi K, Roayaei J, Lien WH, Copeland NG, Jenkins NA, Eisenman RN. An Integrated Genetic-Genomic Approach for the Identification of Novel Cancer Loci in Mice Sensitized to c-Myc-Induced Apoptosis. Genes Cancer 2010; 1:465-479. [PMID: 20927200 DOI: 10.1177/1947601910374875] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Deregulated c-Myc is associated with a wide range of human cancers. In many cell types, overexpression of c-Myc potently promotes cell growth and proliferation concomitant with the induction of apoptosis. Secondary genetic events that shift this balance either by increasing growth and proliferation or limiting apoptosis are likely to cooperate with c-Myc in tumorigenesis. Here, the authors have performed large-scale insertional mutagenesis in Eμ-c-myc mice that, through mdm2 loss of function mutations, are sensitized to apoptosis. The authors chose to use this genetic background based on the hypothesis that the high level of apoptosis induced by c-Myc overexpression in MDM2-deficient mice would act as a rate-limiting barrier for lymphoma development. As a result, it was predicted that the spectrum of retroviral insertions would be shifted toward loci that harbor antiapoptotic genes. Nine novel common insertion sites (CISs) specific to mice with this sensitized genetic background were identified, suggesting the presence of novel antiapoptotic cancer genes. Moreover, cross-comparing the data to the Retroviral Tagged Cancer Gene Database, the authors identified an additional 23 novel CISs. Here, evidence is presented that 2 genes, ppp1r16b and hdac6, identified at CISs, are bona fide cellular oncogenes. This study highlights the power of combining unique sensitized genetic backgrounds with large-scale mutagenesis as an approach for identifying novel cancer genes.
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Affiliation(s)
- Susan M Mendrysa
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
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18
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Tremblay M, Tremblay CS, Herblot S, Aplan PD, Hébert J, Perreault C, Hoang T. Modeling T-cell acute lymphoblastic leukemia induced by the SCL and LMO1 oncogenes. Genes Dev 2010; 24:1093-105. [PMID: 20516195 PMCID: PMC2878648 DOI: 10.1101/gad.1897910] [Citation(s) in RCA: 91] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2009] [Accepted: 04/12/2010] [Indexed: 11/25/2022]
Abstract
Deciphering molecular events required for full transformation of normal cells into cancer cells remains a challenge. In T-cell acute lymphoblastic leukemia (T-ALL), the genes encoding the TAL1/SCL and LMO1/2 transcription factors are recurring targets of chromosomal translocations, whereas NOTCH1 is activated in >50% of samples. Here we show that the SCL and LMO1 oncogenes collaborate to expand primitive thymocyte progenitors and inhibit later stages of differentiation. Together with pre-T-cell antigen receptor (pre-TCR) signaling, these oncogenes provide a favorable context for the acquisition of activating Notch1 mutations and the emergence of self-renewing leukemia-initiating cells in T-ALL. All tumor cells harness identical and specific Notch1 mutations and Tcrbeta clonal signature, indicative of clonal dominance and concurring with the observation that Notch1 gain of function confers a selective advantage to SCL-LMO1 transgenic thymocytes. Accordingly, a hyperactive Notch1 allele accelerates leukemia onset induced by SCL-LMO1 and bypasses the requirement for pre-TCR signaling. Finally, the time to leukemia induced by the three transgenes corresponds to the time required for clonal expansion from a single leukemic stem cell, suggesting that SCL, LMO1, and Notch1 gain of function, together with an active pre-TCR, might represent the minimum set of complementing events for the transformation of susceptible thymocytes.
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Affiliation(s)
- Mathieu Tremblay
- Institute of Research in Immunology and Cancer, University of Montreal, Montréal, Québec H3C 3J7, Canada
| | - Cédric S. Tremblay
- Institute of Research in Immunology and Cancer, University of Montreal, Montréal, Québec H3C 3J7, Canada
| | - Sabine Herblot
- Institute of Research in Immunology and Cancer, University of Montreal, Montréal, Québec H3C 3J7, Canada
| | - Peter D. Aplan
- Center for Cancer Research, National Cancer Institute, Bethesda, Maryland 20892, USA
| | - Josée Hébert
- Banque de Cellules Leucémiques du Québec, Maisonneuve-Rosemont Hospital, Montréal, Québec H1T 2M4, Canada
| | - Claude Perreault
- Institute of Research in Immunology and Cancer, University of Montreal, Montréal, Québec H3C 3J7, Canada
| | - Trang Hoang
- Institute of Research in Immunology and Cancer, University of Montreal, Montréal, Québec H3C 3J7, Canada
- Department of Pharmacology, Faculty of Medicine, University of Montréal, Montréal, Québec H3C 3J7, Canada
- Department of Biochemistry, Faculty of Medicine, University of Montréal, Montréal, Québec H3C 3J7, Canada
- Department of Molecular Biology, Faculty of Medicine, University of Montréal, Montréal, Québec H3C 3J7, Canada
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19
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Abstract
Mouse models of human cancer have played a vital role in understanding tumorigenesis and answering experimental questions that other systems cannot address. Advances continue to be made that allow better understanding of the mechanisms of tumor development, and therefore the identification of better therapeutic and diagnostic strategies. We review major advances that have been made in modeling cancer in the mouse and specific areas of research that have been explored with mouse models. For example, although there are differences between mice and humans, new models are able to more accurately model sporadic human cancers by specifically controlling timing and location of mutations, even within single cells. As hypotheses are developed in human and cell culture systems, engineered mice provide the most tractable and accurate test of their validity in vivo. For example, largely through the use of these models, the microenvironment has been established to play a critical role in tumorigenesis, since tumor development and the interaction with surrounding stroma can be studied as both evolve. These mouse models have specifically fueled our understanding of cancer initiation, immune system roles, tumor angiogenesis, invasion, and metastasis, and the relevance of molecular diversity observed among human cancers. Currently, these models are being designed to facilitate in vivo imaging to track both primary and metastatic tumor development from much earlier stages than previously possible. Finally, the approaches developed in this field to achieve basic understanding are emerging as effective tools to guide much needed development of treatment strategies, diagnostic strategies, and patient stratification strategies in clinical research.
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Affiliation(s)
- Jessica C Walrath
- Mouse Cancer Genetics Program, National Cancer Institute, Frederick, Maryland, USA
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20
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Stem cell exhaustion due to Runx1 deficiency is prevented by Evi5 activation in leukemogenesis. Blood 2009; 115:1610-20. [PMID: 20008790 DOI: 10.1182/blood-2009-07-232249] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
The RUNX1/AML1 gene is the most frequently mutated gene in human leukemia. Conditional deletion of Runx1 in adult mice results in an increase of hematopoietic stem cells (HSCs), which serve as target cells for leukemia; however, Runx1(-/-) mice do not develop spontaneous leukemia. Here we show that maintenance of Runx1(-/-) HSCs is compromised, progressively resulting in HSC exhaustion. In leukemia development, the stem cell exhaustion was rescued by additional genetic changes. Retroviral insertional mutagenesis revealed Evi5 activation as a cooperating genetic alteration and EVI5 overexpression indeed prevented Runx1(-/-) HSC exhaustion in mice. Moreover, EVI5 was frequently overexpressed in human RUNX1-related leukemias. These results provide insights into the mechanism for maintenance of pre-leukemic stem cells and may provide a novel direction for therapeutic applications.
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21
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Meacham CE, Ho EE, Dubrovsky E, Gertler FB, Hemann MT. In vivo RNAi screening identifies regulators of actin dynamics as key determinants of lymphoma progression. Nat Genet 2009; 41:1133-7. [PMID: 19783987 PMCID: PMC2756700 DOI: 10.1038/ng.451] [Citation(s) in RCA: 113] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2009] [Accepted: 07/27/2009] [Indexed: 01/08/2023]
Abstract
Mouse models have markedly improved our understanding of cancer development and tumor biology. However, these models have shown limited efficacy as tractable systems for unbiased genetic experimentation. Here, we report the adaptation of loss-of-function screening to mouse models of cancer. Specifically, we have been able to introduce a library of shRNAs into individual mice using transplantable Emu-myc lymphoma cells. This approach has allowed us to screen nearly 1,000 genetic alterations in the context of a single tumor-bearing mouse. These experiments have identified a central role for regulators of actin dynamics and cell motility in lymphoma cell homeostasis in vivo. Validation experiments confirmed that these proteins represent bona fide lymphoma drug targets. Additionally, suppression of two of these targets, Rac2 and twinfilin, potentiated the action of the front-line chemotherapeutic vincristine, suggesting a critical relationship between cell motility and tumor relapse in hematopoietic malignancies.
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Affiliation(s)
- Corbin E Meacham
- The Koch Institute for Integrative Cancer Research at MIT, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
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22
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Rahrmann EP, Collier LS, Knutson TP, Doyal ME, Kuslak SL, Green LE, Malinowski RL, Roethe L, Akagi K, Waknitz M, Huang W, Largaespada DA, Marker PC. Identification of PDE4D as a proliferation promoting factor in prostate cancer using a Sleeping Beauty transposon-based somatic mutagenesis screen. Cancer Res 2009; 69:4388-97. [PMID: 19401450 DOI: 10.1158/0008-5472.can-08-3901] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Retroviral and transposon-based mutagenesis screens in mice have been useful for identifying candidate cancer genes for some tumor types. However, many of the organs that exhibit the highest cancer rates in humans, including the prostate, have not previously been amenable to these approaches. This study shows for the first time that the Sleeping Beauty transposon system can be used to identify candidate prostate cancer genes in mice. Somatic mobilization of a mutagenic transposon resulted in focal epithelial proliferation and hyperplasia in the prostate. Efficient methods were established to identify transposon insertion sites in these lesions, and analysis of transposon insertions identified candidate prostate cancer genes at common insertion sites, including Pde4d. PDE4D was also overexpressed in human prostate cancer patient samples and cell lines, and changes in PDE4D mRNA isoform expression were observed in human prostate cancers. Furthermore, knockdown of PDE4D reduced the growth and migration of prostate cancer cells in vitro, and knockdown of PDE4D reduced the growth and proliferation rate of prostate cancer xenografts in vivo. These data indicate that PDE4D functions as a proliferation promoting factor in prostate cancer, and the Sleeping Beauty transposon system is a useful tool for identifying candidate prostate cancer genes.
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Affiliation(s)
- Eric P Rahrmann
- Department of Genetics, Cell Biology, and Development and Masonic Cancer Center, University of Minnesota, Minneapolis, MN, USA
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23
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Scobie L, Hector RD, Grant L, Bell M, Nielsen AA, Meikle S, Philbey A, Philbey A, Thrasher AJ, Thrasher AJ, Cameron ER, Blyth K, Neil JC. A novel model of SCID-X1 reconstitution reveals predisposition to retrovirus-induced lymphoma but no evidence of gammaC gene oncogenicity. Mol Ther 2009; 17:1031-8. [PMID: 19337236 DOI: 10.1038/mt.2009.59] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
The emergence of leukemia following gene transfer to restore common cytokine receptor gamma chain (gammaC) function in X-linked severe combined immunodeficiency (SCID-X1) has raised important questions with respect to gene therapy safety. To explore the risk factors involved, we tested the oncogenic potential of human gammaC in new strains of transgenic mice expressing the gene under the control of the CD2 promoter and locus control region (LCR). These mice demonstrated mildly perturbed T-cell development, with an increased proportion of thymic CD8 cells, but showed no predisposition to tumor development even on highly tumor prone backgrounds or after gamma-retrovirus infection. The human CD2-gammaC transgene rescued T and B-cell development in gammaC(-/-) mice but with an age-related delay, mimicking postnatal reconstitution in SCID-X1 gene therapy subjects. However, we noted that gammaC(-/-) mice are acutely susceptible to murine leukemia virus (MLV) leukemogenesis, and that this trait was not corrected by the gammaC transgene. We conclude that the SCID-X1 phenotype can be corrected safely by stable ectopic expression of gammaC and that the transgene is not significantly oncogenic when expressed in this context. However, an underlying predisposition conferred by the SCID-X1 background appears to collaborate with insertional mutagenesis to increase the risk of tumor development.
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Affiliation(s)
- Linda Scobie
- Division of Pathological Sciences, Institute of Comparative Medicine, Faculty of Veterinary Medicine, University of Glasgow, Glasgow, UK.
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24
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Montini E, Cesana D, Schmidt M, Sanvito F, Bartholomae CC, Ranzani M, Benedicenti F, Sergi LS, Ambrosi A, Ponzoni M, Doglioni C, Di Serio C, von Kalle C, Naldini L. The genotoxic potential of retroviral vectors is strongly modulated by vector design and integration site selection in a mouse model of HSC gene therapy. J Clin Invest 2009; 119:964-75. [PMID: 19307726 DOI: 10.1172/jci37630] [Citation(s) in RCA: 409] [Impact Index Per Article: 27.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2008] [Accepted: 01/14/2009] [Indexed: 12/25/2022] Open
Abstract
gamma-Retroviral vectors (gammaRVs), which are commonly used in gene therapy, can trigger oncogenesis by insertional mutagenesis. Here, we have dissected the contribution of vector design and viral integration site selection (ISS) to oncogenesis using an in vivo genotoxicity assay based on transplantation of vector-transduced tumor-prone mouse hematopoietic stem/progenitor cells. By swapping genetic elements between gammaRV and lentiviral vectors (LVs), we have demonstrated that transcriptionally active long terminal repeats (LTRs) are major determinants of genotoxicity even when reconstituted in LVs and that self-inactivating (SIN) LTRs enhance the safety of gammaRVs. By comparing the genotoxicity of vectors with matched active LTRs, we were able to determine that substantially greater LV integration loads are required to approach the same oncogenic risk as gammaRVs. This difference in facilitating oncogenesis is likely to be explained by the observed preferential targeting of cancer genes by gammaRVs. This integration-site bias was intrinsic to gammaRVs, as it was also observed for SIN gammaRVs that lacked genotoxicity in our model. Our findings strongly support the use of SIN viral vector platforms and show that ISS can substantially modulate genotoxicity.
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Affiliation(s)
- Eugenio Montini
- San Raffaele-Telethon Institute for Gene Therapy, via Olgettina 58, 20132 Milan, Italy.
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25
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Liu J, Sørensen AB, Wang B, Wabl M, Nielsen AL, Pedersen FS. Identification of novel Bach2 transcripts and protein isoforms through tagging analysis of retroviral integrations in B-cell lymphomas. BMC Mol Biol 2009; 10:2. [PMID: 19159451 PMCID: PMC2635362 DOI: 10.1186/1471-2199-10-2] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2008] [Accepted: 01/21/2009] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The Bach2 gene functions as a transcriptional repressor in B-cells, showing high expression level only before the plasma cell stage. Several lines of evidence indicate that Bach2 is a B-cell specific tumor suppressor. We here address patterns of insertional mutagenesis and expression of Bach2 is a murine retroviral model of B-cell lymphoma induction. RESULTS We report that the Bach2 gene is a target of proviral integrations in B-cell lymphomas induced by murine leukemia virus. An alternative Bach2 promoter was identified within intron 2 and this promoter was activated in one of the tumors harboring proviral integration. The alternative promoter was active in both normal and tumor tissue and the tissue specificity of the two Bach2 promoters was similar. Three different alternatively used Bach2 terminal exons were identified to be located in intron 4. The inclusion of these exons resulted in the generation of Bach2 mRNA with open reading frames lacking the bZIP DNA binding domain present in the normal Bach2 protein, but retaining a partial BTB protein dimerization domain. Such Bach2 protein was excluded from the cell nucleus. CONCLUSION We have identified an alternative promoter and new protein isoforms of Bach2. Our data imply that activation of an alternative promoter by proviral integration serves as a possible mechanism of up-regulation of the Bach2 gene with a potential role in B-cell lymphomagenesis. The finding of novel Bach2 transcripts and protein isoforms will facilitate a better insight into the normal and pathophysiological regulation of the Bach2 gene.
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Affiliation(s)
- Jinghua Liu
- Department of Molecular Biology, C.F. Møllers Allé 1.130, University of Aarhus, Aarhus C, Denmark.
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26
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Shin DM, Shaffer DJ, Wang H, Roopenian DC, Morse HC. NOTCH is part of the transcriptional network regulating cell growth and survival in mouse plasmacytomas. Cancer Res 2008; 68:9202-11. [PMID: 19010892 DOI: 10.1158/0008-5472.can-07-6555] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Aside from Myc-activating translocations characteristic of plasmacytomas (PCT), little is known about genetic factors and signaling pathways responsible for the development of spontaneous B-cell lineage lymphomas of mice. Here, we characterized the transcriptional profiles of PCT, centroblastic diffuse large B-cell lymphomas (CBL), and high-grade splenic marginal zone B-cell lymphoma (MZL++) using high-throughput quantitative reverse transcription-PCR. Expression profiles of CBL and MZL++ were strikingly similar and quite unlike that of PCT. Among the genes expressed at significantly higher levels by PCT were a number involved in NOTCH signaling, a finding supported by gene set enrichment analyses of microarray data. To investigate the importance of this pathway, NOTCH signaling was blocked in PCT cell lines by treatment with a gamma-secretase inhibitor (GSI) or transduction of a dominant-negative mutant of MAML1. These treatments resulted in reduced expression of NOTCH transcriptional targets in association with impaired proliferation and increased apoptosis. GSI treatment of transformed plasma cells in a primary PCT also induced apoptosis. These results integrate NOTCH activation with oncogenic signaling pathways downstream of translocated Myc in the pathogenesis of mouse PCT, two signaling pathways also implicated in development of human multiple myeloma and T-cell lymphoblastic lymphoma.
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Affiliation(s)
- Dong-Mi Shin
- Laboratory of Immunopathology, National Institute of Allergy and Infectious Diseases, NIH, Rockville, Maryland 20852, USA
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27
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Uren AG, Kool J, Matentzoglu K, de Ridder J, Mattison J, van Uitert M, Lagcher W, Sie D, Tanger E, Cox T, Reinders M, Hubbard TJ, Rogers J, Jonkers J, Wessels L, Adams DJ, van Lohuizen M, Berns A. Large-scale mutagenesis in p19(ARF)- and p53-deficient mice identifies cancer genes and their collaborative networks. Cell 2008; 133:727-41. [PMID: 18485879 PMCID: PMC2405818 DOI: 10.1016/j.cell.2008.03.021] [Citation(s) in RCA: 158] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2007] [Revised: 01/21/2008] [Accepted: 03/10/2008] [Indexed: 01/25/2023]
Abstract
p53 and p19(ARF) are tumor suppressors frequently mutated in human tumors. In a high-throughput screen in mice for mutations collaborating with either p53 or p19(ARF) deficiency, we identified 10,806 retroviral insertion sites, implicating over 300 loci in tumorigenesis. This dataset reveals 20 genes that are specifically mutated in either p19(ARF)-deficient, p53-deficient or wild-type mice (including Flt3, mmu-mir-106a-363, Smg6, and Ccnd3), as well as networks of significant collaborative and mutually exclusive interactions between cancer genes. Furthermore, we found candidate tumor suppressor genes, as well as distinct clusters of insertions within genes like Flt3 and Notch1 that induce mutants with different spectra of genetic interactions. Cross species comparative analysis with aCGH data of human cancer cell lines revealed known and candidate oncogenes (Mmp13, Slamf6, and Rreb1) and tumor suppressors (Wwox and Arfrp2). This dataset should prove to be a rich resource for the study of genetic interactions that underlie tumorigenesis.
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Affiliation(s)
- Anthony G Uren
- Division of Molecular Genetics and Cancer Genomics Centre, Netherlands Cancer Institute, Plesmanlaan 121, 1066CX, Amsterdam, The Netherlands
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28
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Tanaka M, Jin G, Yamazaki Y, Takahara T, Takuwa M, Nakamura T. Identification of candidate cooperative genes of the Apc mutation in transformation of the colon epithelial cell by retroviral insertional mutagenesis. Cancer Sci 2008; 99:979-85. [PMID: 18294281 PMCID: PMC11158175 DOI: 10.1111/j.1349-7006.2008.00757.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2007] [Revised: 01/06/2008] [Accepted: 01/07/2008] [Indexed: 12/18/2022] Open
Abstract
The mutation of Apc is an important early genetic event in colon carcinogenesis. However, it remains to be clarified what kinds of cooperative genes are required for complete carcinogenesis. To identify cooperative genes for the Apc(Min) mutation the authors carried out retroviral insertional mutagenesis (RIM) using Min mouse-derived IMCE colon epithelial cells. Anchorage-independent transformed colonies were induced by retroviral infection only in IMCE cells, while no transformation was found in young adult mouse colon (YAMC) cells that are normal for Apc. One hundred and fifty-seven retroviral integration sites (RIS) were identified in 101 independent transformants, and four common integration sites (CIS), Dnah3, Ahnak, Stk17b and Rbm9, were observed. Upregulation of Dnah3 and Ahnak, and truncation of Dnah3 due to the viral integration, was revealed. In addition, Dnah3-overexpressing IMCE cells showed impairment of microtubule function. These data suggest the importance of cytoskeletal function in Apc-related tumor development and the usefulness of RIM in non-hematopoietic tissues, providing new insight into the early stage of colon carcinogenesis.
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Affiliation(s)
- Miwa Tanaka
- Department of Carcinogenesis, The Cancer Institute, Japanese Foundation for Cancer Research, 3-10-6 Ariake, Koto-ku, Tokyo 135-8550, Japan
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29
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Up-regulation of a cellular protein at the translational level by a retrovirus. Proc Natl Acad Sci U S A 2008; 105:5543-8. [PMID: 18378896 DOI: 10.1073/pnas.0710526105] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Mink cell focus-forming (MCF) murine leukemia viruses (MLVs) are the etiologic agent of thymic lymphoma in mice. We have observed previously that superinfection by MCF13 MLV of certain cell types, such as preleukemic thymic lymphocytes and cultured mink epithelial cells, results in the accumulation of the viral envelope precursor polyprotein, leading to the induction of endoplasmic reticulum (ER) stress. In this study, we demonstrate that the induction of ER stress by MCF13 MLV infection results in an increase in the phosphorylation of the alpha-subunit of eukaryotic initiation factor 2. In cells in which this occurs, we have detected an up-regulation of the cellular inhibitor of apoptosis protein 1 (c-IAP1). The results of real-time RT-PCR quantification of message levels and protein turnover assays indicate that up-regulation of c-IAP1 occurs at the translational level. Elevation of c-IAP1 levels at a posttranscriptional step was detectable in MCF13 MLV-induced thymic lymphomas and chronically infected mink epithelial cells. The ability of a simple retrovirus to regulate cellular gene expression at the translational level may be an important mechanism that contributes to pathogenesis.
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30
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Hackett CS, Geurts AM, Hackett PB. Predicting preferential DNA vector insertion sites: implications for functional genomics and gene therapy. Genome Biol 2007; 8 Suppl 1:S12. [PMID: 18047689 PMCID: PMC2106846 DOI: 10.1186/gb-2007-8-s1-s12] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
Viral and transposon vectors have been employed in gene therapy as well as functional genomics studies. However, the goals of gene therapy and functional genomics are entirely different; gene therapists hope to avoid altering endogenous gene expression (especially the activation of oncogenes), whereas geneticists do want to alter expression of chromosomal genes. The odds of either outcome depend on a vector's preference to integrate into genes or control regions, and these preferences vary between vectors. Here we discuss the relative strengths of DNA vectors over viral vectors, and review methods to overcome barriers to delivery inherent to DNA vectors. We also review the tendencies of several classes of retroviral and transposon vectors to target DNA sequences, genes, and genetic elements with respect to the balance between insertion preferences and oncogenic selection. Theoretically, knowing the variables that affect integration for various vectors will allow researchers to choose the vector with the most utility for their specific purposes. The three principle benefits from elucidating factors that affect preferences in integration are as follows: in gene therapy, it allows assessment of the overall risks for activating an oncogene or inactivating a tumor suppressor gene that could lead to severe adverse effects years after treatment; in genomic studies, it allows one to discern random from selected integration events; and in gene therapy as well as functional genomics, it facilitates design of vectors that are better targeted to specific sequences, which would be a significant advance in the art of transgenesis.
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Affiliation(s)
- Christopher S Hackett
- Biomedical Sciences Graduate Program and Department of Neurology, University of California San Francisco, Room U441K, Parnassus Ave, San Francisco, California 94143-0663, USA
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31
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Weiser KC, Liu B, Hansen GM, Skapura D, Hentges KE, Yarlagadda S, Morse Iii HC, Justice MJ. Retroviral insertions in the VISION database identify molecular pathways in mouse lymphoid leukemia and lymphoma. Mamm Genome 2007; 18:709-22. [PMID: 17926094 PMCID: PMC2042025 DOI: 10.1007/s00335-007-9060-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2007] [Accepted: 07/30/2007] [Indexed: 01/07/2023]
Abstract
AKXD recombinant inbred (RI) strains develop a variety of leukemias and lymphomas due to somatically acquired insertions of retroviral DNA into the genome of hematopoetic cells that can mutate cellular proto-oncogenes and tumor suppressor genes. We generated a new set of tumors from nine AKXD RI strains selected for their propensity to develop B-cell tumors, the most common type of human hematopoietic cancers. We employed a PCR technique called viral insertion site amplification (VISA) to rapidly isolate genomic sequence at the site of provirus insertion. Here we describe 550 VISA sequence tags (VSTs) that identify 74 common insertion sites (CISs), of which 21 have not been identified previously. Several suspected proto-oncogenes and tumor suppressor genes lie near CISs, providing supportive evidence for their roles in cancer. Furthermore, numerous previously uncharacterized genes lie near CISs, providing a pool of candidate disease genes for future research. Pathway analysis of candidate genes identified several signaling pathways as common and powerful routes to blood cancer, including Notch, E-protein, NFκB, and Ras signaling. Misregulation of several Notch signaling genes was confirmed by quantitative RT-PCR. Our data suggest that analyses of insertional mutagenesis on a single genetic background are biased toward the identification of cooperating mutations. This tumor collection represents the most comprehensive study of the genetics of B-cell leukemia and lymphoma development in mice. We have deposited the VST sequences, CISs in a genome viewer, histopathology, and molecular tumor typing data in a public web database called VISION (Viral Insertion Sites Identifying Oncogenes), which is located at http://www.mouse-genome.bcm.tmc.edu/vision.
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Affiliation(s)
- Keith C Weiser
- Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, Texas 77030, USA
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32
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Cavazzana-Calvo M, Fischer A. Gene therapy for severe combined immunodeficiency: are we there yet? J Clin Invest 2007; 117:1456-65. [PMID: 17549248 PMCID: PMC1878528 DOI: 10.1172/jci30953] [Citation(s) in RCA: 173] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Inherited and acquired diseases of the hematopoietic system can be cured by allogeneic hematopoietic stem cell transplantation. This treatment strategy is highly successful when an HLA-matched sibling donor is available, but if not, few therapeutic options exist. Gene-modified, autologous bone marrow transplantation can circumvent the severe immunological complications that occur when a related HLA-mismatched donor is used and thus represents an attractive alternative. In this review, we summarize the advantages and limitations associated with the use of gene therapy to cure SCID. Insertional mutagenesis and technological improvements aimed at increasing the safety of this strategy are also discussed.
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33
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Rodenburg M, Fischer M, Engelmann A, Harbers SO, Ziegler M, Löhler J, Stocking C. Importance of receptor usage, Fli1 activation, and mouse strain for the stem cell specificity of 10A1 murine leukemia virus leukemogenicity. J Virol 2006; 81:732-42. [PMID: 17079317 PMCID: PMC1797452 DOI: 10.1128/jvi.01430-06] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Murine leukemia viruses (MuLV) induce leukemia through a multistage process, a critical step being the activation of oncogenes through provirus integration. Transcription elements within the long terminal repeats (LTR) are prime determinants of cell lineage specificity; however, the influence of other factors, including the Env protein that modulates cell tropism through receptor recognition, has not been rigorously addressed. The ability of 10A1-MuLV to use both PiT1 and PiT2 receptors has been implicated in its induction of blast cell leukemia. Here we show that restricting receptor usage of 10A1-MuLV to PiT2 results in loss of blast cell transformation capacity. However, the pathogenicity was unaltered when the env gene is exchanged with Moloney MuLV, which uses the Cat1 receptor. Significantly, the leukemic blasts express erythroid markers and consistently contain proviral integrations in the Fli1 locus, a target of Friend MuLV (F-MuLV) during erythroleukemia induction. Furthermore, an NB-tropic variant of 10A1 was unable to induce blast cell leukemia in C57BL/6 mice, which are also resistant to F-MuLV transformation. We propose that 10A1- and F-MuLV actually induce identical (erythro)blastic leukemia by a mechanism involving Fli1 activation and cooperation with inherent genetic mutations in susceptible mouse strains. Furthermore, we demonstrate that deletion of the Icsbp tumor suppressor gene in C57BL/6 mice is sufficient to confer susceptibility to 10A1-MuLV leukemia induction but with altered specificity. In summary, we validate the significance of the env gene in leukemia specificity and underline the importance of a complex interplay of cooperating oncogenes and/or tumor suppressors in determining the pathogenicity of MuLV variants.
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MESH Headings
- Animals
- Cells, Cultured
- Fibroblasts
- Gene Products, env/genetics
- Gene Products, env/metabolism
- Hematopoietic Stem Cells/pathology
- Hematopoietic Stem Cells/virology
- Leukemia Virus, Murine/genetics
- Leukemia Virus, Murine/metabolism
- Leukemia Virus, Murine/pathogenicity
- Leukemia, Experimental/pathology
- Leukemia, Experimental/virology
- Mice
- Mice, Inbred C57BL
- Proto-Oncogene Protein c-fli-1/genetics
- Proto-Oncogene Protein c-fli-1/metabolism
- Receptors, Virus/metabolism
- Retroviridae Infections/pathology
- Retroviridae Infections/virology
- Species Specificity
- Tumor Virus Infections/pathology
- Tumor Virus Infections/virology
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34
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Erkeland SJ, Verhaak RGW, Valk PJM, Delwel R, Löwenberg B, Touw IP. Significance of murine retroviral mutagenesis for identification of disease genes in human acute myeloid leukemia. Cancer Res 2006; 66:622-6. [PMID: 16423987 DOI: 10.1158/0008-5472.can-05-2908] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Retroviral insertion mutagenesis is considered a powerful tool to identify cancer genes in mice, but its significance for human cancer has remained elusive. Moreover, it has recently been debated whether common virus integrations are always a hallmark of tumor cells and contribute to the oncogenic process. Acute myeloid leukemia (AML) is a heterogeneous disease with a variable response to treatment. Recurrent cytogenetic defects and acquired mutations in regulatory genes are associated with AML subtypes and prognosis. Recently, gene expression profiling (GEP) has been applied to further risk stratify AML. Here, we show that mouse leukemia genes identified by retroviral insertion mutagenesis are more frequently differentially expressed in distinct subclasses of adult and pediatric AML than randomly selected genes or genes located more distantly from a virus integration site. The candidate proto-oncogenes showing discriminative expression in primary AML could be placed in regulatory networks mainly involved in signal transduction and transcriptional control. Our data support the validity of retroviral insertion mutagenesis in mice for human disease and indicate that combining these murine screens for potential proto-oncogenes with GEP in human AML may help to identify critical disease genes and novel pathogenetic networks in leukemia.
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Affiliation(s)
- Stefan J Erkeland
- Department of Hematology, Erasmus University Medical Center, 3000 DR Rotterdam, the Netherlands
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35
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Hilkens J. Recent translational research: oncogene discovery by insertional mutagenesis gets a new boost. Breast Cancer Res 2006; 8:102. [PMID: 16469121 PMCID: PMC1413991 DOI: 10.1186/bcr1376] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Knowledge of the genes and genetic pathways involved in onco-genesis is essential if we are to identify novel targets for cancer therapy. Insertional mutagenesis in mouse models is among the most efficient tools to detect novel cancer genes. Retrovirus-mediated insertional mutagenesis received a tremendous boost by the availability of the mouse genome sequence and new PCR methods. Application of such advances were limited to lympho-magenesis but are now also being applied to mammary tumourigenesis. Novel transposons that allow insertional muta-genesis studies to be conducted in tumors of any mouse tissue may give cancer gene discovery a further boost.
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Affiliation(s)
- John Hilkens
- Division of Tumor Biology, The Netherlands Cancer Institute, Amsterdam, The Netherlands.
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36
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Yamashita N, Osato M, Huang L, Yanagida M, Kogan SC, Iwasaki M, Nakamura T, Shigesada K, Asou N, Ito Y. Haploinsufficiency of Runx1/AML1 promotes myeloid features and leukaemogenesis in BXH2 mice. Br J Haematol 2006; 131:495-507. [PMID: 16281942 DOI: 10.1111/j.1365-2141.2005.05793.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Haploinsufficiency of RUNX1/AML1 is associated with familial platelet disorder with a predisposition to acute myeloid leukaemia (FPD/AML), but the causal relationship remains to be addressed experimentally. Mice heterozygous for the Runx1 null mutation, Runx1+/-, are considered to be genetically comparable with human FPD/AML patients but do not develop spontaneous leukaemia. To induce additional genetic alterations, retroviral insertional mutagenesis was employed with the use of BXH2 mice, which develop myeloid leukaemia because of the random integration of retrovirus present in the mouse. Heterozygous disruption of Runx1 in BXH2 mice resulted in a shortening of the latency period of leukaemia. In addition, BXH2-Runx1+/- mice exhibited more marked myeloid features than control mice. Moreover, the c-Kit gene, mutated in human RUNX leukaemias, was recurrently activated in BXH2-Runx1+/- mice, and a colony-forming assay revealed synergism between the Runx1+/- status and c-KIT overexpression. In conclusion, the BXH2-Runx1+/- system is a promising mouse model to investigate the mechanism of leukaemogenesis in FPD/AML.
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37
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Chen E, Lim MS, Rosic-Kablar S, Liu J, Jolicoeur P, Dubé ID, Hough MR. Dysregulated expression of mitotic regulators is associated with B-cell lymphomagenesis in HOX11-transgenic mice. Oncogene 2006; 25:2575-87. [PMID: 16407851 DOI: 10.1038/sj.onc.1209285] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Dysregulated expression of the homeobox gene, HOX11 is a frequent etiologic event in T-cell acute lymphoblastic leukemias. HOX11-transgenic mice (IgHmu-HOX11Tg)-expressing HOX11 in the B-cell compartment develop B-cell lymphomas with extended latency. The latency suggests that additional genetic events are required prior to the onset of malignant lymphoma. We report the identification of 17 HOX11 collaborating genes, revealed through their propensity to be targeted in a proviral insertional mutagenesis screen. Seven integrations disrupted genes in mitotic spindle checkpoint control, suggesting that cells with elevated HOX11 expression are especially sensitive to dysregulation of chromosome segregation during mitosis. IgHmu-HOX11Tg primary B-lymphocyte cultures exposed to the aneugenic agents, colchicine and colcemid, exhibited increased incidences of chromosome missegregation as assessed by cytokinesis-block micronucleus assays. Additionally, IgHmu-HOX11Tg cultures were shown to exhibit aberrant bypass of spindle checkpoint arrest, as assessed by the increased presence of cycling cells determined by assessment of DNA content and by BrdU immunolabelling. Western immunoblotting revealed elevated expression of the mitotic effector molecules, cyclin A, cyclin B1 and cdc20 in IgHmu-HOX11Tg cultures. Moreover, spontaneously arising lymphoid neoplasms in IgHmu-HOX11Tg mice frequently exhibit aberrant expression of mitotic regulators, concomitant with increased development of micronuclei, abnormal mitotic checkpoint control and increased incidences of abnormal karyotypes when expanded in culture. Collectively, these findings indicate that abnormal regulation of spindle checkpoint control as a result of HOX11 overexpression leads to a heightened predisposition for development of aneuploidy, contributing to oncogenesis.
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MESH Headings
- Animals
- B-Lymphocytes/metabolism
- B-Lymphocytes/virology
- Bromodeoxyuridine/metabolism
- Cdc20 Proteins
- Cell Cycle Proteins/genetics
- Cell Cycle Proteins/metabolism
- Cyclin A/genetics
- Cyclin A/metabolism
- Cyclin B/genetics
- Cyclin B/metabolism
- Cyclin B1
- Disease Models, Animal
- Female
- Gene Expression Regulation, Neoplastic
- Genes, cdc
- Homeodomain Proteins/genetics
- Humans
- Immunoglobulin Heavy Chains/genetics
- Lymphoma, B-Cell/genetics
- Lymphoma, B-Cell/metabolism
- Lymphoma, B-Cell/pathology
- Male
- Mice
- Mice, Inbred C57BL
- Mice, Transgenic
- Mutagenesis, Insertional
- Proviruses/genetics
- RNA, Messenger/metabolism
- Retroviridae/genetics
- Reverse Transcriptase Polymerase Chain Reaction
- Spindle Apparatus/metabolism
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Affiliation(s)
- E Chen
- Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada
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38
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van den Akker E, Vankan-Berkhoudt Y, Valk PJM, Löwenberg B, Delwel R. The common viral insertion site Evi12 is located in the 5'-noncoding region of Gnn, a novel gene with enhanced expression in two subclasses of human acute myeloid leukemia. J Virol 2005; 79:5249-58. [PMID: 15827139 PMCID: PMC1082726 DOI: 10.1128/jvi.79.9.5249-5258.2005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The leukemia and lymphoma disease locus Evi12 was mapped to the noncoding region of a novel gene, Gnn (named for Grp94 neighboring nucleotidase), that is located immediately upstream of the Grp94/Tra1 gene on mouse chromosome 10. The Gnn gene is conserved in mice and humans. Expression of fusion constructs between GFP and Gnn cDNA isoforms in HEK-293 cells showed that Gnn proteins are located mainly in the cytoplasm. Immunoblotting experiments demonstrated the presence of multiple Gnn protein isoforms in most organs, with the lowest levels of expression of the protein detected in bone marrow and spleen. The Evi12-containing leukemia cell line NFS107 showed high levels of expression of a approximately 150-kDa Gnn isoform (Gnn107) that was not observed in control cell lines. Overexpression may be due to the viral insertion in Evi12. The Gnn107 protein is probably encoded by a Gnn cDNA isoform that is expressed exclusively in NFS107 cells and that includes sequences of TU12B1-TY, a putative protein with homology to 5'-nucleotidase enzymes. Interestingly, using Affymetrix gene expression data of a cohort of 285 patients with acute myeloid leukemia (AML), we found that GNN/TU12B1-TY expression was specifically increased in two AML clusters. One cluster consisted of all AML patients with a t(8;21) translocation, and the second cluster consisted of AML patients with a normal karyotype carrying a FLT3 internal tandem duplication. These findings suggest that we identified a novel proto-oncogene that may be causally linked to certain types of human leukemia.
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Affiliation(s)
- Eric van den Akker
- Department of Hematology, Erasmus University Medical Center, Dr. Molewaterplein 50, 3015 GE Rotterdam, The Netherlands.
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39
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Edel MJ, Shvarts A, Medema JP, Bernards R. An in vivo functional genetic screen reveals a role for the TRK-T3 oncogene in tumor progression. Oncogene 2004; 23:4959-65. [PMID: 15077169 DOI: 10.1038/sj.onc.1207667] [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: 11/09/2022]
Abstract
Over the past decades, much has been learnt about the genes that contribute to oncogenic transformation of primary cells in vitro. However, much less is known about the genes that contribute to the later stages of tumor progression, in which cells of ever increasing malignancy arise through clonal selection in vivo. To search for genes that confer a tumor progression phenotype in vivo, we have used a functional genetic approach. We used adenovirus-transformed mouse embryo fibroblasts, which are tumorigenic in immunodeficient nude mice, but not in immunocompetent mice, due to strong cytotoxic T-cell-mediated immune rejection. We infected these cells in vitro with several high-complexity retroviral cDNA expression libraries and selected rare variants that formed tumors in immunocompetent mice. Using this approach, we identify here the TRK-T3 oncogene as a tumor progression gene. TRK-T3 does not inhibit T-cell reactivity towards the tumor cells. Instead, we find that cells expressing TRK-T3 enhances in vivo growth rate, most likely by stimulating anchorage-independent proliferation in growth factor-limiting conditions. Our data indicate that cDNA expression libraries can be used to identify tumor progression genes in vivo that cannot be readily identified using in vitro cell culture systems.
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Affiliation(s)
- Michael J Edel
- Division of Molecular Carcinogenesis, Center for Biomedical Genetics, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, The Netherlands
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40
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Theodorou V, Boer M, Weigelt B, Jonkers J, van der Valk M, Hilkens J. Fgf10 is an oncogene activated by MMTV insertional mutagenesis in mouse mammary tumors and overexpressed in a subset of human breast carcinomas. Oncogene 2004; 23:6047-55. [PMID: 15208658 DOI: 10.1038/sj.onc.1207816] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Mouse mammary tumor virus (MMTV) infection causes a high incidence of murine mammary carcinomas by insertion of its proviral DNA in the genome of mammary epithelial cells. Retroviral insertion can activate flanking proto-oncogenes by a process called insertional mutagenesis. By sequencing the DNA adjacent to MMTV proviral insertions in mammary tumors from BALB/c mice infected with C3H-MMTV, we have found a common MMTV insertion site in the Fgf10 locus. RT-PCR studies showed that Fgf10 is expressed only in those tumors harboring a MMTV proviral insertion in this locus, suggesting that Fgf10 is a proto-oncogene. The oncogenicity of Fgf10 was evaluated in vivo by subcutaneous transplantation of retrovirally transduced HC11 mammary epithelial cells into BALB/c mice. Highly vascularized invasive subcutaneous tumors developed indicating that Fgf10 can act as an oncogene. A survey of primary human breast carcinomas revealed strongly elevated Fgf10 mRNA levels in approximately 10% of the tumors tested, suggesting that Fgf10 may also be involved in oncogenicity of a subset of human breast cancers.
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Affiliation(s)
- Vassiliki Theodorou
- Division of Tumor Biology, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, The Netherlands
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41
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Castilla LH, Perrat P, Martinez NJ, Landrette SF, Keys R, Oikemus S, Flanegan J, Heilman S, Garrett L, Dutra A, Anderson S, Pihan GA, Wolff L, Liu PP. Identification of genes that synergize with Cbfb-MYH11 in the pathogenesis of acute myeloid leukemia. Proc Natl Acad Sci U S A 2004; 101:4924-9. [PMID: 15044690 PMCID: PMC387350 DOI: 10.1073/pnas.0400930101] [Citation(s) in RCA: 103] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Acute myeloid leukemia subtype M4 with eosinophilia is associated with a chromosome 16 inversion that creates a fusion gene CBFB-MYH11. We have previously shown that CBFB-MYH11 is necessary but not sufficient for leukemogenesis. Here, we report the identification of genes that specifically cooperate with CBFB-MYH11 in leukemogenesis. Neonatal injection of Cbfb-MYH11 knock-in chimeric mice with retrovirus 4070A led to the development of acute myeloid leukemia in 2-5 months. Each leukemia sample contained one or a few viral insertions, suggesting that alteration of one gene could be sufficient to synergize with Cbfb-MYH11. The chromosomal position of 67 independent retroviral insertion sites (RISs) was determined, and 90% of the RISs mapped within 10 kb of a flanking gene. In total, 54 candidate genes were identified; six of them were common insertion sites (CISs). CIS genes included members of a zinc finger transcription factors family, Plag1 and Plagl2, with eight and two independent insertions, respectively. CIS genes also included Runx2, Myb, H2T24, and D6Mm5e. Comparison of the remaining 48 genes with single insertion sites with known leukemia-associated RISs indicated that 18 coincide with known RISs. To our knowledge, this retroviral genetic screen is the first to identify genes that cooperate with a fusion gene important for human myeloid leukemia.
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Affiliation(s)
- L H Castilla
- Program in Gene Function and Expression, University of Massachusetts Medical School, Worcester, MA 01605, USA.
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42
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Ozawa T, Itoyama T, Sadamori N, Yamada Y, Hata T, Tomonaga M, Isobe M. Rapid isolation of viral integration site reveals frequent integration of HTLV-1 into expressed loci. J Hum Genet 2004; 49:154-165. [PMID: 14991527 DOI: 10.1007/s10038-004-0126-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2003] [Accepted: 12/26/2003] [Indexed: 12/31/2022]
Abstract
Although there is tight association of the human T-cell leukemia virus type-1 (HTLV-1) with adult T-cell leukemia/lymphoma (ATLL), it has remained unresolved whether the HTLV-1 integration into the host genome has any role in the development of this disease. We isolated a total of 58 HTLV-1 integration sites using newly developed, adaptor-ligated PCR from 33 ATLL patients and five ATLL cell lines. We compared our data as well as the previously reported ones with the complete human genomic sequence for the location of its placement, structure, and expression of genes nearby the integration site. The chromosomal target for integration was selected at random, but the integration favorably occurred within the transcription units; more than 59.5% of total integration was observed within the transcriptional unit. All inserted genes by HTLV-1 integration were expressed in normal T cells. Upregulation of genes due to viral integration was found in two out of nine ATLL cases; about 4.4- and 102-fold elevated ankyrin-1 ( ANK-1) and gephyrin ( GPHN) gene expressions were observed, respectively. These data suggest that the preferential integration of HTLV-1 into an expressed locus occasionally causes deregulation of corresponding gene, which may lead to leukemogenesis of a fraction of ATLL.
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Affiliation(s)
- Tatsuhiko Ozawa
- Laboratory of Molecular and Cellular Biology, Department of Materials and Biosystem Engineering, Faculty of Engineering, Toyama University, 3190 Gofuku, Toyama 930-8555, Japan
| | - Takahiro Itoyama
- Laboratory of Molecular and Cellular Biology, Department of Materials and Biosystem Engineering, Faculty of Engineering, Toyama University, 3190 Gofuku, Toyama 930-8555, Japan
| | - Naoki Sadamori
- Department of Nursing, Siebold University of Nagasaki, Nagasaki 851-2195, Japan
| | - Yasuaki Yamada
- Division of Laboratory Medicine, Department of Translational Medical Sciences, Nagasaki University Graduate School of Biomedical Sciences, 1-7-1 Sakamoto, Nagasaki 852-8501, Japan
| | - Tomoko Hata
- Department of Hematology, Molecular Medicine Unit, Atomic Bomb Disease Institute, Nagasaki University Graduate School of Biomedical Sciences, 1-12-4 Sakamoto, Nagasaki 852-8523, Japan
| | - Masao Tomonaga
- Department of Hematology, Molecular Medicine Unit, Atomic Bomb Disease Institute, Nagasaki University Graduate School of Biomedical Sciences, 1-12-4 Sakamoto, Nagasaki 852-8523, Japan
| | - Masaharu Isobe
- Laboratory of Molecular and Cellular Biology, Department of Materials and Biosystem Engineering, Faculty of Engineering, Toyama University, 3190 Gofuku, Toyama 930-8555, Japan.
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43
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Erkeland SJ, Valkhof M, Heijmans-Antonissen C, van Hoven-Beijen A, Delwel R, Hermans MHA, Touw IP. Large-scale identification of disease genes involved in acute myeloid leukemia. J Virol 2004; 78:1971-80. [PMID: 14747562 PMCID: PMC369447 DOI: 10.1128/jvi.78.4.1971-1980.2004] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2003] [Accepted: 10/27/2003] [Indexed: 11/20/2022] Open
Abstract
Acute myeloid leukemia (AML) is a heterogeneous group of diseases in which chromosomal aberrations, small insertions or deletions, or point mutations in certain genes have profound consequences for prognosis. However, the majority of AML patients present without currently known genetic defects. Retroviral insertion mutagenesis in mice has become a powerful tool for identifying new disease genes involved in the pathogenesis of leukemia and lymphoma. Here we have used the Graffi-1.4 strain of murine leukemia virus, which causes predominantly AML, in a screen to identify novel genes involved in the pathogenesis of this disease. We report 79 candidate disease genes in common integration sites (CISs) and 15 genes whose family members previously were found to be affected in other studies. The majority of the identified sequences (60%) were not found in lymphomas and monocytic leukemias in previous screens, suggesting a specific involvement in AML. Although most of the virus integrations occurred in or near the 5' or 3' ends of the genes, suggesting deregulation of gene expression as a consequence of virus integration, 18 CISs were located exclusively within the genes, conceivably causing gene disruption.
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Affiliation(s)
- Stefan J Erkeland
- Department of Hematology, Erasmus Medical Center, Rotterdam, The Netherlands
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44
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George A, Morse HC, Justice MJ. The homeobox gene Hex induces T-cell-derived lymphomas when overexpressed in hematopoietic precursor cells. Oncogene 2003; 22:6764-73. [PMID: 14555989 DOI: 10.1038/sj.onc.1206822] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Proviral insertions at the viral insertion site Lvis1 occur frequently in B- and T-cell leukemias and lymphomas in AKXD mice and activate two nearby genes, the divergent homeobox gene Hex and the kinesin-related spindle protein gene Eg5. To determine whether Hex misexpression results in the altered differentiation or neoplastic transformation of hematopoietic lineages, we have transplanted mice with bone marrow cells transduced with retrovirus containing the Hex coding region. High levels of Hex expression in hematopoietic precursor cells inhibit contribution to mature blood cell lineages by these precursors. Hex bone marrow transplant recipient mice also develop hematologic neoplasms that appear to originate in the bone marrow. The tumors have clonal rearrangements of the TCR locus, are Thy1+, and are CD4+CD8+, CD4-CD8-, or mixed, indicating tumor origin from a precursor T-cell population. Tumors in transplant mice contain clonal and transcriptionally active Hex proviral insertions, demonstrating a causal role for Hex misexpression in the onset of these neoplasms. Our results demonstrate that Hex can act as a T lineage oncogene when misexpressed in hematopoietic precursor cells.
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Affiliation(s)
- Alex George
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
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45
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Wolff L, Koller R, Hu X, Anver MR. A Moloney murine leukemia virus-based retrovirus with 4070A long terminal repeat sequences induces a high incidence of myeloid as well as lymphoid neoplasms. J Virol 2003; 77:4965-71. [PMID: 12663802 PMCID: PMC152129 DOI: 10.1128/jvi.77.8.4965-4971.2003] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Retroviruses can be used to accelerate hematopoietic cancers predisposed to neoplastic disease by prior genetic manipulations such as in transgenic or knockout mice. The virus imparts a second neoplastic "hit," providing evidence that the initial hit is transforming. In the present study, a unique retrovirus was developed that can induce a high incidence of myeloid disease and has a broad host range. This agent is a Moloney murine leukemia virus (Mo-MuLV)-based virus that has most of the U3 region of the long terminal repeat (LTR) replaced with that of retrovirus 4070A. Like Mo-MuLV, this virus, called MOL4070LTR, is NB-tropic and not restricted by Fv1 allelles. MOL4070LTR causes myeloid leukemias in ca. 50% of mice, a finding in contrast to Mo-MuLV, which induces almost exclusively lymphoid disease. The data suggest that the LTR of the 4070A virus expands the tissue tropism of the disease to the myeloid lineage. Interesting, MCF recombinant envelope was expressed in the lymphoid but not the myeloid neoplasms of BALB/c mice. This retrovirus has the potential for accelerating myeloid disease in genetically engineered mice.
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Affiliation(s)
- Linda Wolff
- Laboratory of Cellular Oncology, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892-4255, USA.
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46
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Wolf RM, Draghi N, Liang X, Dai C, Uhrbom L, Eklöf C, Westermark B, Holland EC, Resh MD. p190RhoGAP can act to inhibit PDGF-induced gliomas in mice: a putative tumor suppressor encoded on human chromosome 19q13.3. Genes Dev 2003; 17:476-87. [PMID: 12600941 PMCID: PMC196001 DOI: 10.1101/gad.1040003] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
p190RhoGAP and Rho are key regulators of oligodendrocyte differentiation. The gene encoding p190RhoGAP is located at 19q13.3 of the human chromosome, a locus that is deleted in 50%-80% of oligodendrogliomas. Here we provide evidence that p190RhoGAP may suppress gliomagenesis by inducing a differentiated glial phenotype. Using a cell culture model of autocrine loop PDGF stimulation, we show that reduced Rho activity via p190RhoGAP overexpression or Rho kinase inhibition induced cellular process extension, a block in proliferation, and reduced expression of the neural precursor marker nestin. In vivo infection of mice with retrovirus expressing PDGF and the p190 GAP domain caused a decreased incidence of oligodendrogliomas compared with that observed with PDGF alone. Independent experiments revealed that the retroviral vector insertion site in 3 of 50 PDGF-induced gliomas was within the p190RhoGAP gene. This evidence strongly suggests that p190 regulates critical components of PDGF oncogenesis and can act as a tumor suppressor in PDGF-induced gliomas by down-regulating Rho activity.
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Affiliation(s)
- Rebecca M Wolf
- Department of Cell Biology, Memorial Sloan Kettering Cancer Center, New York, New York 10021, USA
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47
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Abstract
Oncogenes involved in the development of hematological malignancies were first discovered through the study of experimental leukemias induced in animals by retroviruses. The discovery that some of these genes were located at the breakpoints of chromosome rearrangements in human malignancies, such as the MYC gene in Burkitt's lymphoma and the ABL gene in chronic myeloid leukemia (CML) has suggested that chromosome abnormalities were causally implicated in the pathogenesis of human diseases. Numerous nonrandom somatically acquired chromosomal translocations or inversions have been identified in human leukemias. The molecular cloning of the genes located at the breakpoints of these rearrangements allowed to identify more than 100 new oncogenes, the products of which affect normal programs of cell proliferation, differentiation and survival. Chromosome translocations can lead to the deregulated expression of a normal gene product, but in most cases of leukemia, chromosome rearrangements result in the expression of a chimeric fusion protein. Oncogene products associated with acute leukemias are often transcription factors while tyrosine kinases and antiapoptotic proteins are more commonly activated or overexpressed in chronic leukemias and in lymphomas. Recent data indicated that gene rearrangements were not the sole gene alterations occurring in human leukemia since point mutations could also affect the function of transcription factors playing a key role in hematopoiesis such as C/EBP alpha, GATA1 and AML1. But the most exciting finding was the discovery of activating point mutations in tyrosine kinase receptors such as FLT3 and c-KIT in acute leukemia. Treatment of leukemia could therefore benefit from new therapeutic approaches targeting the function of specific oncogene products as already demonstrated for CML and acute promyelocytic leukemia.
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Affiliation(s)
- Sylvie Gisselbrecht
- Département d'Hématologie de l'Institut Cochin, Inserm U.567, Cnrs UMR 8104, Bâtiment Gustave Roussy, 27, rue du Faubourg Saint-Jacques, 75014 Paris, France.
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48
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Hanlon L, Barr NI, Blyth K, Stewart M, Haviernik P, Wolff L, Weston K, Cameron ER, Neil JC. Long-range effects of retroviral insertion on c-myb: overexpression may be obscured by silencing during tumor growth in vitro. J Virol 2003; 77:1059-68. [PMID: 12502821 PMCID: PMC140821 DOI: 10.1128/jvi.77.2.1059-1068.2003] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2002] [Accepted: 10/09/2002] [Indexed: 11/20/2022] Open
Abstract
The c-myb oncogene is a frequent target for retroviral activation in hemopoietic tumors of avian and mammalian species. While insertions can target the gene directly, numerous clusters of retroviral insertion sites have been identified which map close to c-myb and outside the transcription unit in T-lymphomas (Ahi-1, fit-1, and Mis-2) and monocytic and myeloid leukemias (Mml1, Mml2, Mml3, and Epi-1). Previous analyses showed no consistent effect of these insertions on c-myb expression, raising the possibility that other nearby genes were the true targets. In contrast, our analysis of four cell lines established from lymphomas bearing insertions at fit-1 (fti-1) (feline leukemia virus) and Ahi-1 (Moloney murine leukemia virus) shows that these display higher expression levels of c-myb RNA and protein compared to a panel of phenotypically similar cell lines lacking such insertions. An interesting feature of the cell lines with long-range c-myb insertions was that each also carried an activated Myc allele. The potential for oncogenic synergy between Myb and Myc in T-cell lymphoma was confirmed in transgenic mice overexpressing alleles of both genes in the T-cell compartment, lending further credence to the case for c-myb as the major target for long-range activation. In contrast, mapping and analysis of c-myb neighboring genes (HBS1 and FLJ20069) showed that the expression of these genes did not correlate well with the presence of proviral insertions. A possible explanation for the paradoxical behavior of c-myb was provided by one of the murine T-lymphoma lines bearing an insertion at Ahi-1 (p/m16i) that reproducibly down-regulated c-myb RNA and protein to very low levels or undetectable levels on prolonged culture. Our observations implicate c-myb as a key target of upstream and downstream retroviral insertions. However, overexpression may become dispensable during outgrowth in vitro, and perhaps during tumor progression in vivo, providing a potential rationale for the previously observed discordance between retroviral insertion and c-myb expression levels.
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Affiliation(s)
- L Hanlon
- Molecular Oncology Laboratory, Department of Veterinary Pathology, University of Glasgow, Bearsden, United Kingdom.
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49
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Denicourt C, Kozak CA, Rassart E. Gris1, a new common integration site in Graffi murine leukemia virus-induced leukemias: overexpression of a truncated cyclin D2 due to alternative splicing. J Virol 2003; 77:37-44. [PMID: 12477808 PMCID: PMC140601 DOI: 10.1128/jvi.77.1.37-44.2003] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The Graffi murine leukemia virus is a nondefective ecotropic retrovirus that was originally reported to induce myeloid leukemia in some strains of mice (A. Graffi, Ann. N.Y. Acad. Sci. 68:540-558, 1957). Using provirus-flanking sequences as DNA probes, we identified a new common retroviral integration site called Gris1 (for Graffi integration site 1). Viral integrations in Gris1 were detected in 13% of the tumors analyzed. The Gris1 locus was mapped to the distal region of mouse chromosome 6, 85 kb upstream of the cyclin D2 gene. Such viral integration in Gris1 causes overexpression of the normal 6.5-kb major transcript of cyclin D2 but also induces the expression of a new, alternatively spliced 1.1-kb transcript from the cyclin D2 gene that encodes a truncated cyclin D2 of 17 kDa. The expression of this 1.1-kb transcript is specific to tumors in which Gris1 is rearranged but is also detected at low levels in normal tissue.
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Affiliation(s)
- Catherine Denicourt
- Laboratoire de Biologie Moléculaire, Département des Sciences Biologiques, Université du Québec à Montréal, Canada
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50
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Mikkers H, Allen J, Berns A. Proviral activation of the tumor suppressor E2a contributes to T cell lymphomagenesis in EμMyc transgenic mice. Oncogene 2002; 21:6559-66. [PMID: 12242653 DOI: 10.1038/sj.onc.1205930] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2002] [Revised: 08/01/2002] [Accepted: 08/01/2002] [Indexed: 11/08/2022]
Abstract
The basic helix-loop-helix factor E2A plays an important role in the development of B and T lymphocytes. In addition, E2a has been implicated as a gene with tumor suppressor activity, since mice deficient for E2a succumb to T cell lymphomas. We have performed retroviral tagging in EmuMyc transgenic mice to identify genes that contribute to lymphomagenesis. The EmuMyc transgenic mouse is a well-established model of a common translocation in human B cell lymphomas. Analyses of the proviral insertion sites in the MuLV-induced lymphomas revealed that a number of T cell lymphomas carried proviral insertions in the promoter region of E2a. These proviral insertions yield hybrid viral-E2a mRNAs resulting in a marked rise in E2A protein levels. The proviral insertions in E2a were predominantly of clonal origin indicating that E2a insertions are early events in these T cell lymphomas. The primary oncogenic effect of E2A is likely to be associated with enhancement of transcription of the c-Myc transgene via binding to the regulatory immunoglobulin enhancers. The results herein thus provide the first evidence that in a specific setting E2A overexpression can contribute to T-lymphomagenesis. This implies that E2a contains oncogenic features in addition to the previously described tumor suppressive properties.
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Affiliation(s)
- Harald Mikkers
- Division of Molecular Genetics and Centre of Biomedical Genetics, Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, The Netherlands
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