251
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Abstract
The phosphoinositide 3-kinase (PI3K)/Akt signaling axis plays an important role in cellular proliferation and growth signaling. With respect to the immune system, a growing body of data is helping to elucidate the role of this pathway in lymphocyte development, as well as to show how perturbations that lead to unregulated activation in this pathway may produce systemic autoimmunity or malignancy. Various knockout and transgenic murine models have been described for key mediators of this signaling pathway. Many of these models resulting in the activation of this pathway demonstrate features of systemic autoimmunity, linking this pathway to autoimmune disease. Here, we review recently described murine models that exhibit activated PI3K/Akt signaling and the potential role this pathway in autoimmune disease, and also discuss the therapeutic implications of these findings.
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Affiliation(s)
- Rahul K Patel
- Department of Rheumatology, UT Southwestern Medical Center at Dallas, Dallas, TX 75390-8884, USA
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252
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Procko E, McColl SR. Leukocytes on the move with phosphoinositide 3-kinase and its downstream effectors. Bioessays 2005; 27:153-63. [PMID: 15666353 DOI: 10.1002/bies.20157] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Cell signalling mediators derived from membrane phospholipids are frequent participants in biological processes. The family of phosphoinositide 3-kinases (PI3Ks) phosphorylate the membrane lipid phosphatidylinositol, generating second messengers that direct diverse responses. These PI3K products are fundamental for leukocyte migration or chemotaxis, a pivotal event during the immune response. This system is therefore of significant biomedical interest. This review focuses on the biochemistry and signalling pathways of PI3K, with particular emphasis on chemokine (chemotactic cytokine)-directed responses. The key objectives of chemotaxis are motility and direction. The latter--direction--requires distinct events at the front and back of a cell. In light of this, the coordinated localisation of signalling factors, an event choreographed by a sharp intracellular gradient of PI3K-derived products, is a common theme.
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Affiliation(s)
- Erik Procko
- School of Molecular & Biomedical Science, The University of Adelaide, Adelaide, SA 5005, Australia
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253
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Niki M, Di Cristofano A, Zhao M, Honda H, Hirai H, Van Aelst L, Cordon-Cardo C, Pandolfi PP. Role of Dok-1 and Dok-2 in leukemia suppression. ACTA ACUST UNITED AC 2005; 200:1689-95. [PMID: 15611295 PMCID: PMC2211998 DOI: 10.1084/jem.20041306] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Chronic myelogenous leukemia (CML) is characterized by the presence of the chimeric p210bcr/abl oncoprotein that shows elevated and constitutive protein tyrosine kinase activity relative to the normal c-abl tyrosine kinase. Although several p210bcr/abl substrates have been identified, their relevance in the pathogenesis of the disease is unclear. We have identified a family of proteins, Dok (downstream of tyrosine kinase), coexpressed in hematopoietic progenitor cells. Members of this family such as p62dok (Dok-1) and p56dok-2 (Dok-2) associate with the p120 rasGTPase-activating protein (rasGAP) upon phosphorylation by p210bcr/abl as well as receptor and nonreceptor tyrosine kinases. Here, we report the generation and characterization of single and double Dok-1 or Dok-2 knockout (KO) mutants. Single KO mice displayed normal steady-state hematopoiesis. By contrast, concomitant Dok-1 and Dok-2 inactivation resulted in aberrant hemopoiesis and Ras/MAP kinase activation. Strikingly, all Dok-1/Dok-2 double KO mutants spontaneously developed transplantable CML-like myeloproliferative disease due to increased cellular proliferation and reduced apoptosis. Furthermore, Dok-1 or Dok-2 inactivation markedly accelerated leukemia and blastic crisis onset in Tec-p210bcr/abl transgenic mice known to develop, after long latency, a myeloproliferative disorder resembling human CML. These findings unravel the critical and unexpected role of Dok-1 and Dok-2 in tumor suppression and control of the hematopoietic compartment homeostasis.
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MESH Headings
- Adaptor Proteins, Signal Transducing/genetics
- Adaptor Proteins, Signal Transducing/metabolism
- Animals
- Apoptosis/genetics
- Blast Crisis/genetics
- Blast Crisis/metabolism
- Blast Crisis/pathology
- Bone Marrow/metabolism
- Bone Marrow/pathology
- Cell Proliferation
- DNA-Binding Proteins/genetics
- DNA-Binding Proteins/metabolism
- Fusion Proteins, bcr-abl/genetics
- Fusion Proteins, bcr-abl/metabolism
- Gene Expression Regulation, Leukemic/genetics
- Hematopoiesis/genetics
- Homeostasis/genetics
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/genetics
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/metabolism
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/pathology
- MAP Kinase Signaling System/genetics
- Mice
- Mice, Knockout
- Mitogen-Activated Protein Kinase 1/metabolism
- Phosphoproteins/genetics
- Phosphoproteins/metabolism
- Phosphorylation
- RNA-Binding Proteins/genetics
- RNA-Binding Proteins/metabolism
- p120 GTPase Activating Protein/metabolism
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Affiliation(s)
- Masaru Niki
- Cancer Biology and Genetics Program and Dept. of Pathology, Box 110, Memorial Sloan-Kettering Cancer Center, 1275 York Ave., New York, NY 10021, USA
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254
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Leslie N, Downes C. PTEN function: how normal cells control it and tumour cells lose it. Biochem J 2005; 382:1-11. [PMID: 15193142 PMCID: PMC1133909 DOI: 10.1042/bj20040825] [Citation(s) in RCA: 323] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2004] [Revised: 06/10/2004] [Accepted: 06/11/2004] [Indexed: 01/26/2023]
Abstract
The PTEN (phosphatase and tensin homologue deleted on chromosome 10) tumour suppressor is a PI (phosphoinositide) 3-phosphatase that can inhibit cellular proliferation, survival and growth by inactivating PI 3-kinase-dependent signalling. It also suppresses cellular motility through mechanisms that may be partially independent of phosphatase activity. PTEN is one of the most commonly lost tumour suppressors in human cancer, and its deregulation is also implicated in several other diseases. Here we discuss recent developments in our understanding of how the cellular activity of PTEN is regulated, and the closely related question of how this activity is lost in tumours. Cellular PTEN function appears to be regulated by controlling both the expression of the enzyme and also its activity through mechanisms including oxidation and phosphorylation-based control of non-substrate membrane binding. Therefore mutation of PTEN in tumours disrupts not only the catalytic function of PTEN, but also its regulatory aspects. However, although mutation of PTEN is uncommon in many human tumour types, loss of PTEN expression seems to be more frequent. It is currently unclear how these tumours lose PTEN expression in the absence of mutation, and while some data implicate other potential tumour suppressors and oncogenes in this process, this area seems likely to be a key focus of future research.
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Affiliation(s)
- Nick R. Leslie
- Division of Cell Signalling, School of Life Sciences, University of Dundee, Dundee DD1 5EH, U.K
- email
| | - C. Peter Downes
- Division of Cell Signalling, School of Life Sciences, University of Dundee, Dundee DD1 5EH, U.K
- email
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255
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Morel J, Berenbaum F. Signal transduction pathways: new targets for treating rheumatoid arthritis. Joint Bone Spine 2005; 71:503-10. [PMID: 15589430 DOI: 10.1016/j.jbspin.2004.03.004] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2003] [Accepted: 03/19/2004] [Indexed: 12/29/2022]
Abstract
Biotherapies and other new treatments introduced over the last few years have considerably enriched the therapeutic armamentarium for rheumatoid arthritis. Nevertheless, primary refractoriness or secondary escape phenomenon may occur, indicating a need for identifying new treatment targets. Promising candidates can be found among compounds involved in signal transduction pathways, most notably protein kinases (mitogen-activated protein kinase, MAPK and phosphatidylinositol-3 protein kinase, PI3) and transcription factors (nuclear factor kappa B, NF-kappaB; activating protein 1, AP-1; CCAAT/enhancer-binding protein, C/EBP and signal transducer and activator of transcription, STAT). Inhibition of signal transduction pathways may be achievable via three main strategies: pharmacological inhibitors, anti-sense or more specific inhibitors such as oligionucleotides or interfering mRNA, and induced overexpression of naturally occurring inhibitors. Clinical trials are under way to evaluate pharmacological inhibitors such as p38 MAPK. Although the preliminary results are promising, proof of safety has not yet been obtained. Signal transduction pathways are involved in normal processes, whose inhibition might produce untoward effects.
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Affiliation(s)
- Jacques Morel
- Immunorheumatology Department and Inserm U454, CHU Lapeyronie Hospital, 371, avenue du Doyen Gaston Giraud, 34295 Montpellier 5, France.
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256
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Marti F, Lapinski PE, King PD. The emerging role of the T cell-specific adaptor (TSAd) protein as an autoimmune disease-regulator in mouse and man. Immunol Lett 2005; 97:165-70. [PMID: 15752554 DOI: 10.1016/j.imlet.2004.10.019] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2004] [Revised: 10/21/2004] [Accepted: 10/25/2004] [Indexed: 11/29/2022]
Abstract
T cell-specific adapter protein is a relatively recently described signaling adapter molecule expressed predominantly in T cells and NK cells. Studies in mouse and man have indicated that reduced expression of TSAd in T cells may predispose toward the development of autoimmune disease. In lupus-prone TSAd-deficient mice the development of autoimmunity is associated with an impaired T cell death response to antigens in vivo. Probably, this impaired death response is consequent to reduced T cell antigen receptor (TCR)-induced synthesis of the interleukin-2 (IL-2) cytokine in TSAd-deficient T cells. TSAd appears to contribute to IL-2 synthesis at multiple different levels acting in both the nucleus and cytoplasm of T cells. Recent advances relating to the role of TSAd in T cell signal transduction and as a regulator of autoimmune responses are discussed.
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Affiliation(s)
- Francesc Marti
- Department of Microbiology and Immunology, University of Michigan Medical School, 6606 Medical Science Building II, Ann Arbor, MI 48109-0620, USA
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257
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Im E, Choi SH, Suh H, Choi YH, Yoo YH, Kim ND. Synthetic bile acid derivatives induce apoptosis through a c-Jun N-terminal kinase and NF-kappaB-dependent process in human cervical carcinoma cells. Cancer Lett 2005; 229:49-57. [PMID: 16157218 DOI: 10.1016/j.canlet.2004.11.055] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2004] [Revised: 11/24/2004] [Accepted: 11/26/2004] [Indexed: 01/12/2023]
Abstract
Recently, we have reported that a synthetic derivative of ursodeoxycholic acid (UDCA), HS-1183, and those of chenodeoxycholic acid (CDCA), HS-1199 and HS-1200, induced apoptosis in human breast carcinoma cells through a p53-independent pathway. Here, we present that the synthetic bile acid derivatives induce apoptosis in SiHa human cervical carcinoma cells as well. The parental compounds, UDCA and CDCA, exhibited no significant effect on the cell viability at the concentration ranges tested. However, their synthetic bile acid derivatives significantly decreased cell viability in a concentration dependent manner. Characteristic manifestations of apoptosis including DNA fragmentation, an increased level of proapoptotic protein Bax, and cleavage of poly(ADP-ribose) polymerase were shown when the cells were treated with these synthetic compounds. Nuclear translocation of nuclear transcription factor NF-kappaB was increased and this suggests that the synthetic compounds induce apoptosis in a NF-kappaB dependent pathway. Phosphorylations of p38 and extracellular signal-regulated kinase were not affected, whereas c-Jun N-terminal kinase (JNK) was activated along with an increased level of transcription factor c-Jun. Our studies demonstrate that the newly synthesized bile acids are capable of inhibiting cell proliferation and inducing apoptosis in SiHa cells through activation of JNK and NF-kappaB.
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Affiliation(s)
- Eunok Im
- Department of Pharmacy and Pusan Cancer Research Center, Pusan National University, Busan 609-735, South Korea
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258
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Datta SK, Zhang L, Xu L. T-helper cell intrinsic defects in lupus that break peripheral tolerance to nuclear autoantigens. J Mol Med (Berl) 2005; 83:267-78. [PMID: 15630591 DOI: 10.1007/s00109-004-0624-2] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2004] [Accepted: 11/16/2004] [Indexed: 12/22/2022]
Abstract
Special populations of T helper cells drive B cells to produce IgG class switched, pathogenic autoantibodies in lupus. The major source of antigenic determinants (epitopes) that trigger interactions between lupus T and B cells is nucleosomes of apoptotic cells. These epitopes can be used for antigen-specific therapy of lupus. Secondly, the autoimmune T cells of lupus are sustained because they resist anergy and activation-induced programmed cell death by markedly upregulating cyclooxygenase (COX) 2 along with the antiapoptotic molecule c-FLIP. Only certain COX-2 inhibitors block pathogenic anti-DNA autoantibody production in lupus by causing death of autoimmune T helper cells. Hence COX-2 inhibitors may work independently of their ability to block the enzymatic function of COX-2, and structural peculiarities of these select inhibitors may lead to better drug discovery and design.
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Affiliation(s)
- Syamal K Datta
- Department of Medicine, Feinberg School of Medicine, Northwestern University, 240 East Huron St., Chicago, IL 60611, USA.
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259
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Khan S, Kumagai T, Vora J, Bose N, Sehgal I, Koeffler PH, Bose S. PTEN promoter is methylated in a proportion of invasive breast cancers. Int J Cancer 2004; 112:407-10. [PMID: 15382065 DOI: 10.1002/ijc.20447] [Citation(s) in RCA: 98] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The PTEN protein is a negative regulator of the Akt pathway, leading to suppression of apoptosis and increased cell survival. Its role as a tumor-suppressor gene has been adequately substantiated, and homozygous mutations have been demonstrated in familial and sporadic cancers. In breast cancers, expression of PTEN protein is lost/reduced in 38% of cases. Somatic mutations are, however, rarely found. Our study was therefore designed to determine if differential methylation of the PTEN promoter region has a role in the transcriptional inactivation of the gene in invasive breast carcinomas. A total of 44 samples of invasive human breast cancer, 5 breast cancer cell lines and 16 samples of normal human breast tissue from young and elderly women were studied for methylation of the PTEN promoter by methylation-specific PCR and PTEN protein expression by immunohistochemistry. PTEN methylation occurred in 34% of breast cancers, and 60% of these samples were associated with loss of PTEN protein. Analyzed from a different perspective, 34% of breast cancers had reduced expression of PTEN and 60% had a methylated PTEN promoter. None of the breast cancer cell lines and normal breast tissues showed methylation. In summary, methylation of the PTEN promoter leads to PTEN inactivation in a subset of human breast cancers.
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Affiliation(s)
- Salma Khan
- Department of Pathology, Cedars Sinai Medical Center, Los Angeles, CA, USA
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260
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Santiago-Raber ML, Laporte C, Reininger L, Izui S. Genetic basis of murine lupus. Autoimmun Rev 2004; 3:33-9. [PMID: 14871647 DOI: 10.1016/s1568-9972(03)00062-4] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/06/2003] [Indexed: 01/12/2023]
Abstract
Systemic lupus erythematosus (SLE) is an autoimmune disorder characterized by the formation of a variety of autoantibodies and subsequent development of severe glomerulonephritis. Etiology of SLE remains unknown even if it is now well established that SLE is under polygenic control as well as the contribution of hormonal and environmental factors. The availability of several murine strains that spontaneously develop an autoimmune syndrome resembling human SLE, such as New Zealand, MRL and BXSB mice has provided useful tools for the genetic dissection of susceptibility to SLE. Moreover, development of various transgenic and mutant mice has made it possible to identify a number of susceptibility genes such as those involved in the regulation of apoptosis or B cell receptor signaling that can trigger lupus-like phenotypes. Obviously, further identification of the genetic defects present in lupus-prone mice is of paramount importance for understanding the immunopathogenesis of SLE.
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261
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Hagenbeek TJ, Naspetti M, Malergue F, Garçon F, Nunès JA, Cleutjens KBJM, Trapman J, Krimpenfort P, Spits H. The loss of PTEN allows TCR alphabeta lineage thymocytes to bypass IL-7 and Pre-TCR-mediated signaling. ACTA ACUST UNITED AC 2004; 200:883-94. [PMID: 15452180 PMCID: PMC2213281 DOI: 10.1084/jem.20040495] [Citation(s) in RCA: 101] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
The phosphatase and tensin homologue deleted on chromosome 10 (PTEN) negatively regulates cell survival and proliferation mediated by phosphoinositol 3 kinases. We have explored the role of the phosphoinositol(3,4,5)P3-phosphatase PTEN in T cell development by analyzing mice with a T cell-specific deletion of PTEN. Pten(flox/flox)Lck-Cre mice developed thymic lymphomas, but before the onset of tumors, they showed normal thymic cellularity. To reveal a regulatory role of PTEN in proliferation of developing T cells we have crossed PTEN-deficient mice with mice deficient for interleukin (IL)-7 receptor and pre-T cell receptor (TCR) signaling. Analysis of mice deficient for Pten and CD3gamma; Pten and gammac; or Pten, gammac, and Rag2 revealed that deletion of PTEN can substitute for both IL-7 and pre-TCR signals. These double- and triple-deficient mice all develop normal levels of CD4CD8 double negative and double positive thymocytes. These data indicate that PTEN is an important regulator of proliferation of developing T cells in the thymus.
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Affiliation(s)
- Thijs J Hagenbeek
- Department of Immunology, Netherlands Cancer Institute, Amsterdam, The Netherlands
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262
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Kyogoku C, Langefeld CD, Ortmann WA, Lee A, Selby S, Carlton VEH, Chang M, Ramos P, Baechler EC, Batliwalla FM, Novitzke J, Williams AH, Gillett C, Rodine P, Graham RR, Ardlie KG, Gaffney PM, Moser KL, Petri M, Begovich AB, Gregersen PK, Behrens TW. Genetic association of the R620W polymorphism of protein tyrosine phosphatase PTPN22 with human SLE. Am J Hum Genet 2004; 75:504-7. [PMID: 15273934 PMCID: PMC1182029 DOI: 10.1086/423790] [Citation(s) in RCA: 525] [Impact Index Per Article: 26.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2004] [Accepted: 06/23/2004] [Indexed: 01/01/2023] Open
Abstract
We genotyped 525 independent North American white individuals with systemic lupus erythematosus (SLE) for the PTPN22 R620W polymorphism and compared the results with data generated from 1,961 white control individuals. The R620W SNP was associated with SLE (genotypic P=.00009), with estimated minor (T) allele frequencies of 12.67% in SLE cases and 8.64% in controls. A single copy of the T allele (W620) increases risk of SLE (odds ratio [OR]=1.37; 95% confidence interval [CI] 1.07-1.75), and two copies of the allele more than double this risk (OR=4.37; 95% CI 1.98-9.65). Together with recent evidence showing association of this SNP with type 1 diabetes and rheumatoid arthritis, these data provide compelling evidence that PTPN22 plays a fundamental role in regulating the immune system and the development of autoimmunity.
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Affiliation(s)
- Chieko Kyogoku
- Department of Medicine, University of Minnesota School of Medicine, Minneapolis; Section on Biostatistics, Wake Forest University School of Medicine, Winston-Salem, NC; Robert S. Boas Center for Genomics and Genetics, North Shore Long Island Jewish Research Institute, Manhasset, NY; Celera Diagnostics, Alameda, CA; Department of Medicine, Massachusetts General Hospital, Boston; Genomics Collaborative, Inc. (GCI), Cambridge, MA; and Department of Medicine, Johns Hopkins University School of Medicine, Baltimore
| | - Carl D. Langefeld
- Department of Medicine, University of Minnesota School of Medicine, Minneapolis; Section on Biostatistics, Wake Forest University School of Medicine, Winston-Salem, NC; Robert S. Boas Center for Genomics and Genetics, North Shore Long Island Jewish Research Institute, Manhasset, NY; Celera Diagnostics, Alameda, CA; Department of Medicine, Massachusetts General Hospital, Boston; Genomics Collaborative, Inc. (GCI), Cambridge, MA; and Department of Medicine, Johns Hopkins University School of Medicine, Baltimore
| | - Ward A. Ortmann
- Department of Medicine, University of Minnesota School of Medicine, Minneapolis; Section on Biostatistics, Wake Forest University School of Medicine, Winston-Salem, NC; Robert S. Boas Center for Genomics and Genetics, North Shore Long Island Jewish Research Institute, Manhasset, NY; Celera Diagnostics, Alameda, CA; Department of Medicine, Massachusetts General Hospital, Boston; Genomics Collaborative, Inc. (GCI), Cambridge, MA; and Department of Medicine, Johns Hopkins University School of Medicine, Baltimore
| | - Annette Lee
- Department of Medicine, University of Minnesota School of Medicine, Minneapolis; Section on Biostatistics, Wake Forest University School of Medicine, Winston-Salem, NC; Robert S. Boas Center for Genomics and Genetics, North Shore Long Island Jewish Research Institute, Manhasset, NY; Celera Diagnostics, Alameda, CA; Department of Medicine, Massachusetts General Hospital, Boston; Genomics Collaborative, Inc. (GCI), Cambridge, MA; and Department of Medicine, Johns Hopkins University School of Medicine, Baltimore
| | - Scott Selby
- Department of Medicine, University of Minnesota School of Medicine, Minneapolis; Section on Biostatistics, Wake Forest University School of Medicine, Winston-Salem, NC; Robert S. Boas Center for Genomics and Genetics, North Shore Long Island Jewish Research Institute, Manhasset, NY; Celera Diagnostics, Alameda, CA; Department of Medicine, Massachusetts General Hospital, Boston; Genomics Collaborative, Inc. (GCI), Cambridge, MA; and Department of Medicine, Johns Hopkins University School of Medicine, Baltimore
| | - Victoria E. H. Carlton
- Department of Medicine, University of Minnesota School of Medicine, Minneapolis; Section on Biostatistics, Wake Forest University School of Medicine, Winston-Salem, NC; Robert S. Boas Center for Genomics and Genetics, North Shore Long Island Jewish Research Institute, Manhasset, NY; Celera Diagnostics, Alameda, CA; Department of Medicine, Massachusetts General Hospital, Boston; Genomics Collaborative, Inc. (GCI), Cambridge, MA; and Department of Medicine, Johns Hopkins University School of Medicine, Baltimore
| | - Monica Chang
- Department of Medicine, University of Minnesota School of Medicine, Minneapolis; Section on Biostatistics, Wake Forest University School of Medicine, Winston-Salem, NC; Robert S. Boas Center for Genomics and Genetics, North Shore Long Island Jewish Research Institute, Manhasset, NY; Celera Diagnostics, Alameda, CA; Department of Medicine, Massachusetts General Hospital, Boston; Genomics Collaborative, Inc. (GCI), Cambridge, MA; and Department of Medicine, Johns Hopkins University School of Medicine, Baltimore
| | - Paula Ramos
- Department of Medicine, University of Minnesota School of Medicine, Minneapolis; Section on Biostatistics, Wake Forest University School of Medicine, Winston-Salem, NC; Robert S. Boas Center for Genomics and Genetics, North Shore Long Island Jewish Research Institute, Manhasset, NY; Celera Diagnostics, Alameda, CA; Department of Medicine, Massachusetts General Hospital, Boston; Genomics Collaborative, Inc. (GCI), Cambridge, MA; and Department of Medicine, Johns Hopkins University School of Medicine, Baltimore
| | - Emily C. Baechler
- Department of Medicine, University of Minnesota School of Medicine, Minneapolis; Section on Biostatistics, Wake Forest University School of Medicine, Winston-Salem, NC; Robert S. Boas Center for Genomics and Genetics, North Shore Long Island Jewish Research Institute, Manhasset, NY; Celera Diagnostics, Alameda, CA; Department of Medicine, Massachusetts General Hospital, Boston; Genomics Collaborative, Inc. (GCI), Cambridge, MA; and Department of Medicine, Johns Hopkins University School of Medicine, Baltimore
| | - Franak M. Batliwalla
- Department of Medicine, University of Minnesota School of Medicine, Minneapolis; Section on Biostatistics, Wake Forest University School of Medicine, Winston-Salem, NC; Robert S. Boas Center for Genomics and Genetics, North Shore Long Island Jewish Research Institute, Manhasset, NY; Celera Diagnostics, Alameda, CA; Department of Medicine, Massachusetts General Hospital, Boston; Genomics Collaborative, Inc. (GCI), Cambridge, MA; and Department of Medicine, Johns Hopkins University School of Medicine, Baltimore
| | - Jill Novitzke
- Department of Medicine, University of Minnesota School of Medicine, Minneapolis; Section on Biostatistics, Wake Forest University School of Medicine, Winston-Salem, NC; Robert S. Boas Center for Genomics and Genetics, North Shore Long Island Jewish Research Institute, Manhasset, NY; Celera Diagnostics, Alameda, CA; Department of Medicine, Massachusetts General Hospital, Boston; Genomics Collaborative, Inc. (GCI), Cambridge, MA; and Department of Medicine, Johns Hopkins University School of Medicine, Baltimore
| | - Adrienne H. Williams
- Department of Medicine, University of Minnesota School of Medicine, Minneapolis; Section on Biostatistics, Wake Forest University School of Medicine, Winston-Salem, NC; Robert S. Boas Center for Genomics and Genetics, North Shore Long Island Jewish Research Institute, Manhasset, NY; Celera Diagnostics, Alameda, CA; Department of Medicine, Massachusetts General Hospital, Boston; Genomics Collaborative, Inc. (GCI), Cambridge, MA; and Department of Medicine, Johns Hopkins University School of Medicine, Baltimore
| | - Clarence Gillett
- Department of Medicine, University of Minnesota School of Medicine, Minneapolis; Section on Biostatistics, Wake Forest University School of Medicine, Winston-Salem, NC; Robert S. Boas Center for Genomics and Genetics, North Shore Long Island Jewish Research Institute, Manhasset, NY; Celera Diagnostics, Alameda, CA; Department of Medicine, Massachusetts General Hospital, Boston; Genomics Collaborative, Inc. (GCI), Cambridge, MA; and Department of Medicine, Johns Hopkins University School of Medicine, Baltimore
| | - Peter Rodine
- Department of Medicine, University of Minnesota School of Medicine, Minneapolis; Section on Biostatistics, Wake Forest University School of Medicine, Winston-Salem, NC; Robert S. Boas Center for Genomics and Genetics, North Shore Long Island Jewish Research Institute, Manhasset, NY; Celera Diagnostics, Alameda, CA; Department of Medicine, Massachusetts General Hospital, Boston; Genomics Collaborative, Inc. (GCI), Cambridge, MA; and Department of Medicine, Johns Hopkins University School of Medicine, Baltimore
| | - Robert R. Graham
- Department of Medicine, University of Minnesota School of Medicine, Minneapolis; Section on Biostatistics, Wake Forest University School of Medicine, Winston-Salem, NC; Robert S. Boas Center for Genomics and Genetics, North Shore Long Island Jewish Research Institute, Manhasset, NY; Celera Diagnostics, Alameda, CA; Department of Medicine, Massachusetts General Hospital, Boston; Genomics Collaborative, Inc. (GCI), Cambridge, MA; and Department of Medicine, Johns Hopkins University School of Medicine, Baltimore
| | - Kristin G. Ardlie
- Department of Medicine, University of Minnesota School of Medicine, Minneapolis; Section on Biostatistics, Wake Forest University School of Medicine, Winston-Salem, NC; Robert S. Boas Center for Genomics and Genetics, North Shore Long Island Jewish Research Institute, Manhasset, NY; Celera Diagnostics, Alameda, CA; Department of Medicine, Massachusetts General Hospital, Boston; Genomics Collaborative, Inc. (GCI), Cambridge, MA; and Department of Medicine, Johns Hopkins University School of Medicine, Baltimore
| | - Patrick M. Gaffney
- Department of Medicine, University of Minnesota School of Medicine, Minneapolis; Section on Biostatistics, Wake Forest University School of Medicine, Winston-Salem, NC; Robert S. Boas Center for Genomics and Genetics, North Shore Long Island Jewish Research Institute, Manhasset, NY; Celera Diagnostics, Alameda, CA; Department of Medicine, Massachusetts General Hospital, Boston; Genomics Collaborative, Inc. (GCI), Cambridge, MA; and Department of Medicine, Johns Hopkins University School of Medicine, Baltimore
| | - Kathy L. Moser
- Department of Medicine, University of Minnesota School of Medicine, Minneapolis; Section on Biostatistics, Wake Forest University School of Medicine, Winston-Salem, NC; Robert S. Boas Center for Genomics and Genetics, North Shore Long Island Jewish Research Institute, Manhasset, NY; Celera Diagnostics, Alameda, CA; Department of Medicine, Massachusetts General Hospital, Boston; Genomics Collaborative, Inc. (GCI), Cambridge, MA; and Department of Medicine, Johns Hopkins University School of Medicine, Baltimore
| | - Michelle Petri
- Department of Medicine, University of Minnesota School of Medicine, Minneapolis; Section on Biostatistics, Wake Forest University School of Medicine, Winston-Salem, NC; Robert S. Boas Center for Genomics and Genetics, North Shore Long Island Jewish Research Institute, Manhasset, NY; Celera Diagnostics, Alameda, CA; Department of Medicine, Massachusetts General Hospital, Boston; Genomics Collaborative, Inc. (GCI), Cambridge, MA; and Department of Medicine, Johns Hopkins University School of Medicine, Baltimore
| | - Ann B. Begovich
- Department of Medicine, University of Minnesota School of Medicine, Minneapolis; Section on Biostatistics, Wake Forest University School of Medicine, Winston-Salem, NC; Robert S. Boas Center for Genomics and Genetics, North Shore Long Island Jewish Research Institute, Manhasset, NY; Celera Diagnostics, Alameda, CA; Department of Medicine, Massachusetts General Hospital, Boston; Genomics Collaborative, Inc. (GCI), Cambridge, MA; and Department of Medicine, Johns Hopkins University School of Medicine, Baltimore
| | - Peter K. Gregersen
- Department of Medicine, University of Minnesota School of Medicine, Minneapolis; Section on Biostatistics, Wake Forest University School of Medicine, Winston-Salem, NC; Robert S. Boas Center for Genomics and Genetics, North Shore Long Island Jewish Research Institute, Manhasset, NY; Celera Diagnostics, Alameda, CA; Department of Medicine, Massachusetts General Hospital, Boston; Genomics Collaborative, Inc. (GCI), Cambridge, MA; and Department of Medicine, Johns Hopkins University School of Medicine, Baltimore
| | - Timothy W. Behrens
- Department of Medicine, University of Minnesota School of Medicine, Minneapolis; Section on Biostatistics, Wake Forest University School of Medicine, Winston-Salem, NC; Robert S. Boas Center for Genomics and Genetics, North Shore Long Island Jewish Research Institute, Manhasset, NY; Celera Diagnostics, Alameda, CA; Department of Medicine, Massachusetts General Hospital, Boston; Genomics Collaborative, Inc. (GCI), Cambridge, MA; and Department of Medicine, Johns Hopkins University School of Medicine, Baltimore
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263
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Moody JL, Jirik FR. Compound heterozygosity for Pten and SHIP augments T-dependent humoral immune responses and cytokine production by CD(4+) T cells. Immunology 2004; 112:404-12. [PMID: 15196208 PMCID: PMC1782497 DOI: 10.1111/j.1365-2567.2004.01901.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
Tight regulation of the phosphatidylinositiol 3-kinase (PI3K) pathway is essential not only for normal immune system development and responsiveness, but also in the prevention of immunopathology. Indeed, unchecked activation of the PI3K pathway in T cells induces lymphoproliferation and systemic autoimmunity. Evaluating the importance of threshold levels of two key PI3K pathway phosphoinositol phosphatases, we previously reported that mice heterozygous for both Pten and SHIP develop a more rapid progression of a lymphoproliferative autoimmune syndrome than do Pten(+\-) mice. Investigating the basis for this difference, we now describe a quantitative and qualitative difference in the antibody responses of C57BL\6 Pten(+\-) SHIP(+\-) mice upon challenge with a T-dependent antigen. Suspecting that this phenotypic difference might be the result, at least in part, of a T-helper cell defect, an in vitro analysis of anti-CD3/interleukin (IL)-2-expanded CD4(+) T cells was performed. After stimulation with anti-CD3, cells from mice heterozygous for both Pten and SHIP exhibited a striking increase in IL-4 secretion (> 10-fold), without a corresponding increase in T helper 2 (Th2) cell numbers being evident by intracellular staining for this cytokine. Modest increases were also seen for both IL-13 and IFN-gamma. Perhaps in keeping with this abnormal in vitro cytokine profile, IgG1 serum levels were significantly elevated in young C57BL\6 Pten(+\-) SHIP(+\-) mice. Thus, the relative levels of Pten and SHIP appear to be key variables in CD4(+) T-cell function, primarily via their ability to regulate IL-4 production.
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Affiliation(s)
- J L Moody
- Department of Biochemistry and Molecular Biology, and Joint Injury and Arthritis Research Group, University of Calgary, Calgary, Alberta, Canada
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264
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Bensinger SJ, Walsh PT, Zhang J, Carroll M, Parsons R, Rathmell JC, Thompson CB, Burchill MA, Farrar MA, Turka LA. Distinct IL-2 receptor signaling pattern in CD4+CD25+ regulatory T cells. THE JOURNAL OF IMMUNOLOGY 2004; 172:5287-96. [PMID: 15100267 PMCID: PMC2842445 DOI: 10.4049/jimmunol.172.9.5287] [Citation(s) in RCA: 210] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Despite expression of the high-affinity IL-2R, CD4(+)CD25(+) regulatory T cells (Tregs) are hypoproliferative upon IL-2R stimulation in vitro. However the mechanisms by which CD4(+)CD25(+) T cells respond to IL-2 signals are undefined. In this report, we examine the cellular and molecular responses of CD4(+)CD25(+) Tregs to IL-2. IL-2R stimulation results in a G(1) cell cycle arrest, cellular enlargement and increased cellular survival of CD4(+)CD25(+) T cells. We find a distinct pattern of IL-2R signaling in which the Janus kinase/STAT pathway remains intact, whereas IL-2 does not activate downstream targets of phosphatidylinositol 3-kinase. Negative regulation of phosphatidylinositol 3-kinase signaling and IL-2-mediated proliferation of CD4(+)CD25(+) T cells is inversely associated with expression of the phosphatase and tensin homologue deleted on chromosome 10, PTEN.
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MESH Headings
- Animals
- Cell Division/immunology
- Cell Survival/immunology
- Cells, Cultured
- Down-Regulation/immunology
- Growth Inhibitors/physiology
- Interleukin-2/antagonists & inhibitors
- Interleukin-2/physiology
- Mice
- Mice, Inbred BALB C
- Oligonucleotide Array Sequence Analysis
- PTEN Phosphohydrolase
- Phosphatidylinositol 3-Kinases/physiology
- Phosphoinositide-3 Kinase Inhibitors
- Phosphorylation
- Protein Serine-Threonine Kinases/metabolism
- Protein Tyrosine Phosphatases/antagonists & inhibitors
- Protein Tyrosine Phosphatases/biosynthesis
- Proto-Oncogene Proteins/metabolism
- Proto-Oncogene Proteins c-akt
- Receptors, Antigen, T-Cell/immunology
- Receptors, Interleukin-2/biosynthesis
- Receptors, Interleukin-2/physiology
- Signal Transduction/immunology
- T-Lymphocytes, Regulatory/cytology
- T-Lymphocytes, Regulatory/enzymology
- T-Lymphocytes, Regulatory/immunology
- T-Lymphocytes, Regulatory/metabolism
- Transcription Factors/biosynthesis
- Transcription Factors/genetics
- Tumor Suppressor Proteins/antagonists & inhibitors
- Tumor Suppressor Proteins/biosynthesis
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Affiliation(s)
| | - Patrick T. Walsh
- Department of Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Jidong Zhang
- Department of Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Martin Carroll
- Department of Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Ramon Parsons
- Department of Pathology and Medicine, Columbia University, New York, NY 10032
| | - Jeffrey C. Rathmell
- Abramson Family Cancer Research Institute, Departments of Cancer Biology and Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Craig B. Thompson
- Abramson Family Cancer Research Institute, Departments of Cancer Biology and Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Matthew A. Burchill
- Center for Immunology, Cancer Center, Department of Laboratory Medicine and Pathology, University of Minnesota, Minneapolis, MN 55455
| | - Michael A. Farrar
- Center for Immunology, Cancer Center, Department of Laboratory Medicine and Pathology, University of Minnesota, Minneapolis, MN 55455
| | - Laurence A. Turka
- Department of Medicine, University of Pennsylvania, Philadelphia, PA 19104
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265
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Abstract
Genetic alterations targeting the PTEN tumor suppressor gene are among the most frequently noted somatic mutations in human cancers. Such lesions have been noted in cancers of the prostate and endometrium and in glioblastoma multiforme, among many others. Moreover, germline mutation of PTEN leads to the development of the related hereditary cancer predisposition syndromes, Cowden disease, and Bannayan-Zonana syndrome, wherein breast and thyroid cancer incidence is elevated. The protein product, PTEN, is a lipid phosphatase, the enzymatic activity of which primarily serves to remove phosphate groups from key intracellular phosphoinositide signaling molecules. This activity normally serves to restrict growth and survival signals by limiting activity of the phosphoinositide-3 kinase (PI3K) pathway. Multiple lines of evidence support the notion that this function is critical to the ability of PTEN to maintain cell homeostasis. Indeed, the absence of functional PTEN in cancer cells leads to constitutive activation of downstream components of the PI3K pathway including the Akt and mTOR kinases. In model organisms, inactivation of these kinases can reverse the effects of PTEN loss. These data raise the possibility that drugs targeting these kinases, or PI3K itself, might have significant therapeutic activity in PTEN-null cancers. Akt kinase inhibitors are still in development; however, as a first test of this hypothesis, phase I and phase II trials of inhibitors of mTOR, namely, rapamycin and rapamycin analogs are underway.
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Affiliation(s)
- Isabelle Sansal
- Department of Medical Oncology, Dana-Farber Cancer Institute, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, 44 Binney Street, Boston, MA 02115, USA
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266
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Abstract
Peripheral tolerance is an important strategy used by the immune system to prevent self-reactive lymphocytes from attacking host tissues. A variety of mechanisms contribute to peripheral tolerance, among them activation-induced cell death, suppression by regulatory T cells, and T cell anergy or unresponsiveness. Recent work has led to a better understanding of the cell-intrinsic program that establishes T cell anergy. A major insight is that during the induction phase of anergy, incomplete stimulation (T cell receptor stimulation without costimulation) leads via calcium influx to an altered gene expression program that includes up-regulation of several E3 ubiquitin ligases. When the anergic T cells contact antigen-presenting cells, intracellular signaling proteins are monoubiquitinated and targeted for lysosomal degradation, thus decreasing intracellular signaling and also resulting in decreased stability of the T cell-antigen-presenting cell contact. We propose a molecular program leading to T cell anergy and discuss other proteins that may play a role.
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Affiliation(s)
- Vigo Heissmeyer
- Department of Pathology, Harvard Medical School, and CBR Institute for Biomedical Research, 200 Longwood Avenue, Boston, MA 02115, USA
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267
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Choi C, Jeong E, Benveniste EN. Caspase-1 mediates Fas-induced apoptosis and is up-regulated by interferon-gamma in human astrocytoma cells. J Neurooncol 2004; 67:167-76. [PMID: 15072464 DOI: 10.1023/b:neon.0000021896.52664.9e] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Resistance to Fas-mediated apoptosis contributes to tumor evasion from the host immune system and enables tumors to mediate alternative responses such as inflammation and angiogenesis. In this study, we investigated the molecular mechanisms of the resistance to Fas-mediated apoptosis and sensitization to Fas-induced cell death by IFN-gamma in human astrocytoma cells. To address this, we investigated the expression of thirty-three genes related to the Fas signal transduction pathways using RNase protection assay in five different human astrocytoma cells. Patterns of expression of these genes were similar between different cell lines and did not correlate with sensitivity to Fas-mediated cell death. Treatment with IFN-gamma increased the mRNA expression of caspases-1, -4 and -7 in addition to those of Fas and TRAIL in a time- and dose-dependent manner. Studies using specific caspase inhibitors showed that Fas-induced cell death was mediated by caspases-1, -3 and 8 in the Fas-sensitive human astrocytoma cell lines, CRT-J and U87-MG. We further demonstrated that these caspases were proteolytically cleaved upon Fas ligation in these cells. Interestingly, caspase-1 protein expression but not that of caspase-3 nor -8 was up-regulated by IFN-gamma only in Fas-sensitive CRT-J cells but not in Fas-resistant U373-MG cells. These results collectively suggest that caspase-1, along with caspases-3 and -8, mediate Fas-induced cell death in human astrocytoma cells, and post-transcriptional regulation of caspase-1 may determine the responsiveness to IFN-gamma-induced sensitization to Fas-mediated apoptosis.
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Affiliation(s)
- Chulhee Choi
- Division of Molecular Life Sciences and Center for Cell Signaling Research, Ewha Womans University, Seoul, Korea.
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268
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Holland EC, Sonenberg N, Pandolfi PP, Thomas G. Signaling control of mRNA translation in cancer pathogenesis. Oncogene 2004; 23:3138-44. [PMID: 15094763 DOI: 10.1038/sj.onc.1207590] [Citation(s) in RCA: 126] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The regulation of translation and the control of ribosome biogenesis are essential cellular processes whose impact on cell growth and proliferation is manifested at a number of specific levels. Disruption in one or more of the steps that control protein biosynthesis has been associated with alterations in the regulation of cell growth and cell cycle progression. Consistent with this, tumor suppressors and proto-oncogenes have been found to act on these functions and may therefore regulate malignant progression by affecting the protein synthetic machinery. Although many studies have correlated deregulation of protein biosynthesis with cancer, it remains to be established whether this process is necessary and/or sufficient for neoplastic transformation and metastasis.
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Affiliation(s)
- Eric C Holland
- Department of Surgery, Memorial Sloan-Kettering Cancer Center, 1275 York Avenue, New York, NY 10021, USA.
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269
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Cheema ZF, Santillano DR, Wade SB, Newman JM, Miranda RC. The extracellular matrix, p53 and estrogen compete to regulate cell-surface Fas/Apo-1 suicide receptor expression in proliferating embryonic cerebral cortical precursors, and reciprocally, Fas-ligand modifies estrogen control of cell-cycle proteins. BMC Neurosci 2004; 5:11. [PMID: 15038834 PMCID: PMC395829 DOI: 10.1186/1471-2202-5-11] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2003] [Accepted: 03/23/2004] [Indexed: 01/19/2023] Open
Abstract
BACKGROUND Apoptosis is important for normal cerebral cortical development. We previously showed that the Fas suicide receptor was expressed within the developing cerebral cortex, and that in vitro Fas activation resulted in caspase-dependent death. Alterations in cell-surface Fas expression may significantly influence cortical development. Therefore, in the following studies, we sought to identify developmentally relevant cell biological processes that regulate cell-surface Fas expression and reciprocal consequences of Fas receptor activation. RESULTS Flow-cytometric analyses identified two distinct neural sub-populations that expressed Fas on their cell surface at high (FasHi) or moderate (FasMod) levels. The anti-apoptotic protein FLIP further delineated a subset of Fas-expressing cells with potential apoptosis-resistance. FasMod precursors were mainly in G0, while FasHi precursors were largely apoptotic. However, birth-date analysis indicated that neuroblasts express the highest levels of cell-surface Fas at the end of S-phase, or after their final round of mitosis, suggesting that Fas expression is induced at cell cycle checkpoints or during interkinetic nuclear movements. FasHi expression was associated with loss of cell-matrix adhesion and anoikis. Activation of the transcription factor p53 was associated with induction of Fas expression, while the gonadal hormone estrogen antagonistically suppressed cell-surface Fas expression. Estrogen also induced entry into S-phase and decreased the number of Fas-expressing neuroblasts that were apoptotic. Concurrent exposure to estrogen and to soluble Fas-ligand (sFasL) suppressed p21/waf-1 and PCNA. In contrast, estrogen and sFasL, individually and together, induced cyclin-A expression, suggesting activation of compensatory survival mechanisms. CONCLUSIONS Embryonic cortical neuronal precursors are intrinsically heterogeneous with respect to Fas suicide-sensitivity. Competing intrinsic (p53, cell cycle, FLIP expression), proximal (extra-cellular matrix) and extrinsic factors (gonadal hormones) collectively regulate Fas suicide-sensitivity either during neurogenesis, or possibly during neuronal migration, and may ultimately determine which neuroblasts successfully contribute neurons to the differentiating cortical plate.
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Affiliation(s)
- Zulfiqar F Cheema
- Department of Human Anatomy & Medical Neurobiology, & Center for Environmental and Rural Health, 228 Reynolds Medical Bldg., Texas A&M University System Health Science Center, College Station, TX 77843-1114, USA
- Department of General Surgery, William Beaumont Hospital, Royal Oaks, MI 48073, USA
| | - Daniel R Santillano
- Department of Human Anatomy & Medical Neurobiology, & Center for Environmental and Rural Health, 228 Reynolds Medical Bldg., Texas A&M University System Health Science Center, College Station, TX 77843-1114, USA
| | - Stephen B Wade
- Department of Human Anatomy & Medical Neurobiology, & Center for Environmental and Rural Health, 228 Reynolds Medical Bldg., Texas A&M University System Health Science Center, College Station, TX 77843-1114, USA
- Pediatrics, Wake Forest University Baptist Medical Center, Medical Center Boulevard, Winston Salem, NC 27157, USA
| | - Joseph M Newman
- Department of Human Anatomy & Medical Neurobiology, & Center for Environmental and Rural Health, 228 Reynolds Medical Bldg., Texas A&M University System Health Science Center, College Station, TX 77843-1114, USA
| | - Rajesh C Miranda
- Department of Human Anatomy & Medical Neurobiology, & Center for Environmental and Rural Health, 228 Reynolds Medical Bldg., Texas A&M University System Health Science Center, College Station, TX 77843-1114, USA
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270
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Moody JL, Xu L, Helgason CD, Jirik FR. Anemia, thrombocytopenia, leukocytosis, extramedullary hematopoiesis, and impaired progenitor function in Pten+/-SHIP-/- mice: a novel model of myelodysplasia. Blood 2004; 103:4503-10. [PMID: 15001465 DOI: 10.1182/blood-2003-09-3262] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
The myeloproliferative disorder of mice lacking the Src homology 2 (SH2)-containing 5' phosphoinositol phosphatase, SHIP, underscores the need for closely regulating phosphatidylinositol 3-kinase (PI3K) pathway activity, and hence levels of phosphatidylinositol species during hematopoiesis. The role of the 3' phosphoinositol phosphatase Pten in this process is less clear, as its absence leads to embryonic lethality. Despite Pten heterozygosity being associated with a lymphoproliferative disorder, we found no evidence of a hematopoietic defect in Pten(+/-) mice. Since SHIP shares the same substrate (PIP(3)) with Pten, we hypothesized that the former might compensate for Pten haploinsufficiency in the marrow. Thus, we examined the effect of Pten heterozygosity in SHIP(-/-) mice, predicting that further dysregulation of PIP(3) metabolism would exacerbate the pheno-type of the latter. Indeed, compared with SHIP(-/-) mice, Pten(+/-)SHIP(-/-) animals developed a myelodysplastic phenotype characterized by increased hepatosplenomegaly, extramedullary hematopoiesis, anemia, and thrombocytopenia. Consistent with a marrow defect, clonogenic assays demonstrated reductions in committed myeloid and megakaryocytic progenitors in these animals. Providing further evidence of a Pten(+/-)SHIP(-/-) progenitor abnormality, reconstitution of irradiated mice with marrows from these mice led to a marked defect in short-term repopulation of peripheral blood by donor cells. These studies suggest that the regulation of the levels and/or ratios of PI3K-derived phosphoinositol species by these 2 phosphatases is critical to normal hematopoiesis.
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Affiliation(s)
- Jennifer L Moody
- Department of Biochemistry and Molecular Biology, University of Calgary, 3330 Hospital Drive NW, Calgary, Alberta, Canada T2N 4N1
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271
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Li L, He F, Litofsky NS, Recht LD, Ross AH. Profiling of genes expressed by PTEN haploinsufficient neural precursor cells. Mol Cell Neurosci 2004; 24:1051-61. [PMID: 14697668 DOI: 10.1016/j.mcn.2003.08.010] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
PTEN is a lipid phosphatase, and PTEN mutations are associated with gliomas, macrocephaly, and mental deficiencies. We have used PTEN +/- and PTEN +/+ mice to prepare subventricular zone (SVZ) precursor cells. Using DNA microarrays, we compared the expression profiles of PTEN +/+ and PTEN +/- cells and identified 91 differentially expressed genes in PTEN +/- precursor cells. Many of the PTEN-regulated genes are involved with signaling, cytoskeleton, extracellular matrix, metabolism, and transcription factors. Some of these changes are likely mediated by the transcription factor, HIF-1. We confirmed a subset of these changes by real-time PCR. In addition, we examined protein levels for two of the PTEN-up-regulated genes, vascular endothelial growth factor (VEGF) and doublecortin (DCX). PTEN haploinsufficiency increases immunostaining for VEGF for both cultured precursor cells and sections of the SVZ. PTEN haploinsufficiency shifted most of the DCX-positive cells from the SVZ to the olfactory bulb. These observations indicate that even a small decrease in PTEN levels results in substantial changes in gene expression and precursor cell function.
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Affiliation(s)
- Li Li
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, 364 Plantation Street, Worcester, MA 01605, USA
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272
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Vasudevan KM, Gurumurthy S, Rangnekar VM. Suppression of PTEN expression by NF-kappa B prevents apoptosis. Mol Cell Biol 2004; 24:1007-21. [PMID: 14729949 PMCID: PMC321419 DOI: 10.1128/mcb.24.3.1007-1021.2004] [Citation(s) in RCA: 195] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
NF-kappa B is a heterodimeric transcription activator consisting of the DNA binding subunit p50 and the transactivation subunit p65/RelA. NF-kappa B prevents cell death caused by tumor necrosis factor (TNF) and other genotoxic insults by directly inducing antiapoptotic target genes. We report here that the tumor suppressor PTEN, which functions as a negative regulator of phosphatidylinositol (PI)-3 kinase/Akt-mediated cell survival pathway, is down regulated by p65 but not by p50. Moreover, a subset of human lung or thyroid cancer cells expressing high levels of endogenous p65 showed decreased expression of PTEN that could be rescued by specific inhibition of the NF-kappa B pathway with I kappa B overexpression as well as with small interfering RNA directed against p65. Importantly, TNF, a potent inducer of NF-kappa B activity, suppressed PTEN gene expression in IKK beta(+/+) cells but not in IKK beta(-/-) cells, which are deficient in the NF-kappa B activation pathway. These findings indicated that NF-kappa B activation was necessary and sufficient for inhibition of PTEN expression. The promoter, RNA, and protein levels of PTEN are down-regulated by NF-kappa B. The mechanism underlying suppression of PTEN expression by NF-kappa B was independent of p65 DNA binding or transcription function and involved sequestration of limiting pools of transcriptional coactivators CBP/p300 by p65. Restoration of PTEN expression inhibited NF-kappa B transcriptional activity and augmented TNF-induced apoptosis, indicating a negative regulatory loop involving PTEN and NF-kappa B. PTEN is, thus, a novel target whose suppression is critical for antiapoptosis by NF-kappa B.
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Affiliation(s)
- Krishna Murthi Vasudevan
- Department of Microbiology, Immunology, and Molecular Genetics, University of Kentucky, Lexington, Kentucky 40536, USA
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273
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Nassif NT, Lobo GP, Wu X, Henderson CJA, Morrison CD, Eng C, Jalaludin B, Segelov E. PTEN mutations are common in sporadic microsatellite stable colorectal cancer. Oncogene 2004; 23:617-28. [PMID: 14724591 DOI: 10.1038/sj.onc.1207059] [Citation(s) in RCA: 112] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The tumour suppressor gene PTEN, located at chromosome sub-band 10q23.3, encodes a dual-specificity phosphatase that negatively regulates the phosphatidylinositol 3'-kinase (PI3 K)/Akt-dependent cellular survival pathway. PTEN is frequently inactivated in many tumour types including glioblastoma, prostate and endometrial cancers. While initial studies reported that PTEN gene mutations were rare in colorectal cancer, more recent reports have shown an approximate 18% incidence of somatic PTEN mutations in colorectal tumours exhibiting microsatellite instability (MSI+). To verify the role of this gene in colorectal tumorigenesis, we analysed paired normal and tumour DNA from 41 unselected primary sporadic colorectal cancers for PTEN inactivation by mutation and/or allelic loss. We now report PTEN gene mutations in 19.5% (8/41) of tumours and allele loss, including all or part of the PTEN gene, in a further 17% (7/41) of the cases. Both PTEN alleles were affected in over half (9/15) of these cases showing PTEN genetic abnormalities. Using immunohistochemistry, we have further shown that all tumours harbouring PTEN alterations have either reduced or absent PTEN expression and this correlated strongly with later clinical stage of tumour at presentation (P=0.02). In contrast to previous reports, all but one of the tumours with PTEN gene mutations were microsatellite stable (MSI-), suggesting that PTEN is involved in a distinct pathway of colorectal tumorigenesis that is separate from the pathway of mismatch repair deficiency. This work therefore establishes the importance of PTEN in primary sporadic colorectal cancer.
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Affiliation(s)
- Najah T Nassif
- Cancer Research Laboratories, South West Sydney Clinical School, University of New South Wales, Liverpool Hospital, Liverpool, NSW 2170, Australia.
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274
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Seminario MC, Precht P, Wersto RP, Gorospe M, Wange RL. PTEN expression in PTEN-null leukaemic T cell lines leads to reduced proliferation via slowed cell cycle progression. Oncogene 2003; 22:8195-204. [PMID: 14603260 DOI: 10.1038/sj.onc.1206872] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The balance of activities between the proto-oncogene phosphoinositide 3-kinase (PI3K) and the tumour suppressor gene PTEN has been shown to affect cellular growth and proliferation, as well as tumorigenesis. Previously, PTEN expression in the PTEN-null Jurkat T cell leukaemia line was shown to cause reduced proliferation without cell cycle arrest. Here, we further these investigations by determining the basis for this phenomenon. By BrdU pulse-chase and cell cycle arrest and release assays, we find that PTEN expression reduced proliferation by slowing progression through all phases of the cell cycle. This was associated with reduced levels of cyclins A, B1 and B2, cdk4, and cdc25A and increased p27KIP1 expression. Apoptosis played no role in the antiproliferative effect of PTEN, since only marginal increases in the rate of apoptosis were detected upon PTEN expression, and inhibitors of effector caspases did not restore proliferative capacity. Active Akt blocked the antiproliferative effects of PTEN, indicating that PTEN mediates its effects through conventional PI3K-linked signalling pathways. Similar results were obtained from a different PTEN-null leukaemia T cell line, CEM. Together, these results show that PTEN expression in leukaemic T cells leads to reduced proliferation via an apoptosis-independent mechanism involving slower passage through the cell cycle.
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Affiliation(s)
- Maria-Cristina Seminario
- Laboratory of Cellular and Molecular Biology, National Institute on Aging, IRP/NIH/DHHS, Baltimore, MD 21224, USA
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275
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Hu CL, Cowan RG, Harman RM, Quirk SM. Cell cycle progression and activation of Akt kinase are required for insulin-like growth factor I-mediated suppression of apoptosis in granulosa cells. Mol Endocrinol 2003; 18:326-38. [PMID: 14593075 DOI: 10.1210/me.2003-0178] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Ovarian follicle development is dependent on growth factors that stimulate cell proliferation and act as survival factors to prevent apoptosis of follicle cells. We examined the mechanism of the protective effect of IGF-I against Fas ligand-induced apoptosis of granulosa cells and its relationship to cell proliferation. IGF-I activated both the phosphoinositide 3'-OH kinase (PI3K) and the MAPK pathways. Experiments using specific inhibitors of these pathways showed that protection by IGF-I was mediated by the PI3K pathway and not the MAPK pathway. Recombinant adenoviruses were used to test whether the downstream target of PI3K activation, Akt kinase, was required for protection against apoptosis. Expression of dominant negative Akt prevented protection by IGF-I whereas expression of constitutively active Akt (myrAkt) mimicked the effect of IGF-I. Treatment with IGF-I, or expression of myrAkt, increased progression from G(0)/G(1) to S phase of the cell cycle whereas expression of dominant negative Akt inhibited G(0)/G(1) to S phase progression and prevented the stimulatory effect of IGF-I. We tested whether cell cycle progression was required for protection from apoptosis using the cyclin-dependent kinase-2 inhibitor roscovitine, which blocks cells at the G(1)/S transition. Roscovitine prevented the protective effect of IGF-I and myrAkt expression against apoptosis. Therefore, activation of Akt is not sufficient to protect granulosa cells from apoptosis in the absence of cell cycle progression. In summary, IGF-I protects granulosa cells from apoptosis by activation of the PI3K/Akt pathway. This protective effect can occur only when progression from G(1) to S phase of the cell cycle regulated by the PI3K/Akt pathway is unperturbed.
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Affiliation(s)
- Che-Lin Hu
- Department of Animal Science, Cornell University, Ithaca, New York 14853, USA
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276
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Trotman LC, Niki M, Dotan ZA, Koutcher JA, Di Cristofano A, Xiao A, Khoo AS, Roy-Burman P, Greenberg NM, Dyke TV, Cordon-Cardo C, Pandolfi PP. Pten dose dictates cancer progression in the prostate. PLoS Biol 2003; 1:E59. [PMID: 14691534 PMCID: PMC270016 DOI: 10.1371/journal.pbio.0000059] [Citation(s) in RCA: 546] [Impact Index Per Article: 26.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2003] [Accepted: 09/24/2003] [Indexed: 11/18/2022] Open
Abstract
Complete inactivation of the PTEN tumor suppressor gene is extremely common in advanced cancer, including prostate cancer (CaP). However, one PTEN allele is already lost in the vast majority of CaPs at presentation. To determine the consequence of PTEN dose variations on cancer progression, we have generated by homologous recombination a hypomorphic Pten mouse mutant series with decreasing Pten activity: Pten(hy/+) > Pten(+/-) > Pten(hy/-) (mutants in which we have rescued the embryonic lethality due to complete Pten inactivation) > Pten prostate conditional knockout (Pten(pc)) mutants. In addition, we have generated and comparatively analyzed two distinct Pten(pc) mutants in which Pten is inactivated focally or throughout the entire prostatic epithelium. We find that the extent of Pten inactivation dictate in an exquisite dose-dependent fashion CaP progression, its incidence, latency, and biology. The dose of Pten affects key downstream targets such as Akt, p27(Kip1), mTOR, and FOXO3. Our results provide conclusive genetic support for the notion that PTEN is haploinsufficient in tumor suppression and that its dose is a key determinant in cancer progression.
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Affiliation(s)
- Lloyd C Trotman
- 1Molecular Biology Program, Memorial Sloan–Kettering Cancer Center, Sloan–Kettering InstituteNew York, New YorkUnited States of America
- 2Department of Pathology, Memorial Sloan–Kettering Cancer Center, Sloan–Kettering InstituteNew York, New YorkUnited States of America
| | - Masaru Niki
- 1Molecular Biology Program, Memorial Sloan–Kettering Cancer Center, Sloan–Kettering InstituteNew York, New YorkUnited States of America
- 2Department of Pathology, Memorial Sloan–Kettering Cancer Center, Sloan–Kettering InstituteNew York, New YorkUnited States of America
| | - Zohar A Dotan
- 1Molecular Biology Program, Memorial Sloan–Kettering Cancer Center, Sloan–Kettering InstituteNew York, New YorkUnited States of America
- 2Department of Pathology, Memorial Sloan–Kettering Cancer Center, Sloan–Kettering InstituteNew York, New YorkUnited States of America
| | - Jason A Koutcher
- 3Department of Radiology, Memorial Sloan–Kettering Cancer Center, Sloan–Kettering InstituteNew York, New YorkUnited States of America
| | - Antonio Di Cristofano
- 1Molecular Biology Program, Memorial Sloan–Kettering Cancer Center, Sloan–Kettering InstituteNew York, New YorkUnited States of America
- 2Department of Pathology, Memorial Sloan–Kettering Cancer Center, Sloan–Kettering InstituteNew York, New YorkUnited States of America
| | - Andrew Xiao
- 4Department of Biochemistry and Biophysics, University of North Carolina at Chapel HillChapel Hill, North CarolinaUnited States of America
| | - Alan S Khoo
- 1Molecular Biology Program, Memorial Sloan–Kettering Cancer Center, Sloan–Kettering InstituteNew York, New YorkUnited States of America
- 2Department of Pathology, Memorial Sloan–Kettering Cancer Center, Sloan–Kettering InstituteNew York, New YorkUnited States of America
| | - Pradip Roy-Burman
- 5Departments of Pathology and Biochemistry and Molecular Biology, Keck School of Medicine, University of Southern CaliforniaLos Angeles, CaliforniaUnited States of America
| | - Norman M Greenberg
- 6Departments of Molecular and Cellular Biology and Urology, Baylor College of MedicineHouston, TexasUnited States of America
| | - Terry Van Dyke
- 4Department of Biochemistry and Biophysics, University of North Carolina at Chapel HillChapel Hill, North CarolinaUnited States of America
| | - Carlos Cordon-Cardo
- 2Department of Pathology, Memorial Sloan–Kettering Cancer Center, Sloan–Kettering InstituteNew York, New YorkUnited States of America
| | - Pier Paolo Pandolfi
- 1Molecular Biology Program, Memorial Sloan–Kettering Cancer Center, Sloan–Kettering InstituteNew York, New YorkUnited States of America
- 2Department of Pathology, Memorial Sloan–Kettering Cancer Center, Sloan–Kettering InstituteNew York, New YorkUnited States of America
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277
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Ciechomska I, Pyrzynska B, Kazmierczak P, Kaminska B. Inhibition of Akt kinase signalling and activation of Forkhead are indispensable for upregulation of FasL expression in apoptosis of glioma cells. Oncogene 2003; 22:7617-27. [PMID: 14576824 DOI: 10.1038/sj.onc.1207137] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Activation of Akt signalling pathway is frequently found in glioma cells and may contribute to their resistance to undergo apoptosis in response to conventional therapies. We found that cyclosporin A (CsA) induces apoptosis of C6 glioma cells, which is associated with transcriptional activation of fasL. In the present paper, we investigated an involvement of Akt signalling in the regulation of FasL expression in CsA-induced apoptosis. We demonstrated that the level of active Akt decreases significantly after CsA treatment, which results in the decrease of Forkhead phosphorylation and its translocation to the nucleus. It correlated with an increase of binding to the Forkhead-responsive element FHRE from the FasL promoter, as demonstrated by gel-shift assays. Although treatment with LY294002, a specific inhibitor of PI3 K, decreased the phosphorylation of Akt and increased Fkhr translocation to the nucleus, these events were not sufficient to induce FasL expression and apoptosis of C6 glioma cells. Interference with Akt/Forkhead signalling by membrane-targeted Akt or removal of the FKHR-binding sites from the FasL promoter significantly abolished its activation. These results indicate that downregulation of Akt signalling and activation of Forkhead is a prerequisite for the induction of FasL promoter. It may be clinically important for pharmacological intervention in gliomas.
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Affiliation(s)
- Iwona Ciechomska
- Laboratory of Transcription Regulation, Department of Cellular Biochemistry, Nencki Institute of Experimental Biology, 3 Pasteur Str., 02-093 Warsaw, Poland
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278
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Goberdhan DCI, Wilson C. PTEN: tumour suppressor, multifunctional growth regulator and more. Hum Mol Genet 2003; 12 Spec No 2:R239-48. [PMID: 12928488 DOI: 10.1093/hmg/ddg288] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
The tumour suppressor gene PTEN is mutated in a wide range of human cancers at a frequency roughly comparable with p53. In addition, germline PTEN mutations are associated with several dominant growth disorders. The molecular and cellular basis of these disorders has been elucidated by detailed in vivo genetic analysis in model organisms, in particular the fruit fly and mouse. Studies in the fly have shown that PTEN's growth regulatory functions are primarily mediated via its lipid phosphatase activity, which specifically reduces the cellular levels of phosphatidylinositol 3,4,5-trisphosphate. This activity antagonizes the effects of activated PI3-kinase in the nutritionally controlled insulin receptor pathway, thereby reducing protein synthesis and restraining cell and organismal growth, while also regulating other biological processes, such as fertility and ageing. Remarkably, this range of functions appears to be conserved in all higher organisms. PTEN also plays a role as a specialized cytoskeletal regulator, which, for example, is involved in directional movement of some migratory cells and may be important in metastasis. Furthermore, conditional knockouts in the mouse have recently revealed functions for PTEN in other processes, such as cell type specification and cardiac muscle contractility. Genetic approaches have therefore revealed a surprising diversity of global and cell type-specific PTEN-regulated functions that appear to be primarily controlled by modulation of a single phosphoinositide. Together with evidence from studies in cell culture that suggests links between PTEN and other growth regulatory genes such as p53, these studies provide new insights into PTEN-linked disorders and are beginning to suggest potential clinical strategies to combat these and other diseases.
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279
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Ruzinova MB, Schoer RA, Gerald W, Egan JE, Pandolfi PP, Rafii S, Manova K, Mittal V, Benezra R. Effect of angiogenesis inhibition by Id loss and the contribution of bone-marrow-derived endothelial cells in spontaneous murine tumors. Cancer Cell 2003; 4:277-89. [PMID: 14585355 DOI: 10.1016/s1535-6108(03)00240-x] [Citation(s) in RCA: 208] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Angiogenic defects in Id mutant mice inhibit the growth of tumor xenografts, providing a genetic model for antiangiogenic stress. Our work tests the consequences of such stress on progression of more physiological Pten+/- tumors. While tumor growth occurs despite impaired angiogenesis, disruption of vasculature by Id loss causes tumor cells to experience hypoxia and necrosis, the extent of which is tumor dependent. We show that bone-marrow-derived endothelial precursors contribute functionally to neovasculature of some but not all Pten+/- tumors, partially rescuing Id mutant phenotype. We demonstrate that loss of Id1 in tumor endothelial cells results in downregulation of several proangiogenic genes, including alpha6 and beta4 integrins, matrix metalloprotease-2, and fibroblast growth factor receptor-1. Inhibition of these factors phenocopies loss of Id in in vivo angiogenesis assays.
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MESH Headings
- Animals
- Bone Marrow/metabolism
- Cell Hypoxia
- Cells, Cultured
- Endothelial Cells/metabolism
- Endothelium, Vascular/physiopathology
- Female
- Fish Proteins
- Inhibitor of Differentiation Protein 1
- Inhibitor of Differentiation Proteins
- Integrin alpha6/metabolism
- Integrin beta4/metabolism
- Lymph Nodes/physiopathology
- Matrix Metalloproteinase 2/metabolism
- Mice
- Mice, Knockout
- Neoplasm Proteins/metabolism
- Neoplasms, Experimental/physiopathology
- Neovascularization, Pathologic/metabolism
- PTEN Phosphohydrolase
- Protein Tyrosine Phosphatase, Non-Receptor Type 1
- Protein Tyrosine Phosphatases/genetics
- Protein Tyrosine Phosphatases/metabolism
- Receptor Protein-Tyrosine Kinases/metabolism
- Receptor, Fibroblast Growth Factor, Type 1
- Receptors, Fibroblast Growth Factor/metabolism
- Repressor Proteins
- Thrombospondin 1/metabolism
- Transcription Factors/genetics
- Transcription Factors/metabolism
- Transplantation, Heterologous
- Uterine Neoplasms/physiopathology
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Affiliation(s)
- Marianna B Ruzinova
- Program of Cell Biology, Memorial Sloan-Kettering Cancer Center, New York, NY 10021, USA
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280
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Campbell RB, Liu F, Ross AH. Allosteric activation of PTEN phosphatase by phosphatidylinositol 4,5-bisphosphate. J Biol Chem 2003; 278:33617-20. [PMID: 12857747 DOI: 10.1074/jbc.c300296200] [Citation(s) in RCA: 163] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Phosphatase and tensin homologue deleted on chromosome 10 (PTEN) is a tumor suppressor that is lost in many human tumors and encodes a phosphatidylinositol phosphate phosphatase specific for the 3-position of the inositol ring. Here we report a novel mechanism of PTEN regulation. Binding of di-C8-phosphatidylinositol 4,5-P2 (PI(4,5)P2) to PTEN enhances phosphatase activity for monodispersed substrates, PI(3,4,5)P3 and PI(3,4)P2. PI(5)P also is an activator, but PI(4)P, PI(3,4)P2, and PI(3,5)P2 do not activate PTEN. Activation by exogenous PI(4,5)P2 is more apparent with PI(3,4)P2 as a substrate than with PI(3,4,5)P3, probably because hydrolysis of PI(3,4)P2 yields PI(4)P, which is not an activator. In contrast, hydrolysis of PI(3,4,5)P3 yields a potent activator, PI(4,5)P2, creating a positive feedback loop. In addition, neither di-C4-PI(4,5)P2 nor inositol trisphosphate-activated PTEN. Hence, the interaction between PI(4,5)P2 and PTEN requires specific, ionic interactions with the phosphate groups on the inositol ring as well as hydrophobic interactions with the fatty acid chains, likely mimicking the physiological interactions that PTEN has with the polar surface head groups and the hydrophobic core of phospholipid membranes. Mutations of the apparent PI(4,5)P2-binding motif in the PTEN N terminus severely reduced PTEN activity. In contrast, mutation of the C2 phospholipid-binding domain had little effect on PTEN activation. These results suggest a model in which a PI(4,5)P2 monomer binds to PTEN, initiates an allosteric conformational change and, thereby, activates PTEN independent of membrane binding.
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Affiliation(s)
- Robert B Campbell
- University of Massachusetts Medical School, Department of Biochemistry and Molecular Pharmacology, Worcester, Massachusetts 01605, USA
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281
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Zhong XP, Hainey EA, Olenchock BA, Jordan MS, Maltzman JS, Nichols KE, Shen H, Koretzky GA. Enhanced T cell responses due to diacylglycerol kinase zeta deficiency. Nat Immunol 2003; 4:882-90. [PMID: 12883552 DOI: 10.1038/ni958] [Citation(s) in RCA: 188] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2003] [Accepted: 06/27/2003] [Indexed: 11/09/2022]
Abstract
Much is known about how T cell receptor (TCR) engagement leads to T cell activation; however, the mechanisms terminating TCR signaling remain less clear. Diacylglycerol, generated after TCR ligation, is essential in T cells. Its function must be controlled tightly to maintain normal T cell homeostasis. Previous studies have shown that diacylglycerol kinase zeta (DGKzeta), which converts diacylglycerol to phosphatidic acid, can inhibit TCR signaling. Here we show that DGKzeta-deficient T cells are hyperresponsive to TCR stimulation both ex vivo and in vivo. Furthermore, DGKzeta-deficient mice mounted a more robust immune response to lymphocytic choriomeningitis virus infection than did wild-type mice. These results demonstrate the importance of DGKzeta as a physiological negative regulator of TCR signaling and T cell activation.
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MESH Headings
- Animals
- Antigens, CD/immunology
- Antigens, CD/metabolism
- Antigens, Differentiation, T-Lymphocyte/immunology
- Antigens, Differentiation, T-Lymphocyte/metabolism
- Cell Division/immunology
- DNA-Binding Proteins/immunology
- DNA-Binding Proteins/metabolism
- Diacylglycerol Kinase/deficiency
- Diacylglycerol Kinase/immunology
- Flow Cytometry
- Guanine Nucleotide Exchange Factors
- Immunoblotting
- Lectins, C-Type
- Lymphocyte Activation/immunology
- Lymphocytic Choriomeningitis/immunology
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Phosphatidic Acids/immunology
- Phosphatidic Acids/metabolism
- Receptors, Antigen, T-Cell/immunology
- Receptors, Interleukin-2/immunology
- Receptors, Interleukin-2/metabolism
- Signal Transduction/immunology
- T-Lymphocytes/cytology
- T-Lymphocytes/enzymology
- T-Lymphocytes/immunology
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Affiliation(s)
- Xiao-Ping Zhong
- The Signal Transduction Program, The Abramson Family Cancer Research Institute, Philadelphia, Pennsylvania 19104, USA
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282
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Abstract
PTEN, on 10q23.3, encodes a major lipid phosphatase which signals down the phosphoinositol-3-kinase/Akt pathway and effects G1 cell cycle arrest and apoptosis. Germline PTEN mutations have been found to occur in 80% of classic Cowden syndrome (CS), 60% of Bannayan-Riley-Ruvalcaba syndrome (BRRS), up to 20% of Proteus syndrome (PS), and approximately 50% of a Proteus-like syndrome (PSL). CS is a heritable multiple hamartoma syndrome with a high risk of breast, thyroid, and endometrial carcinomas. BRRS is a congenital autosomal dominant disorder characterized by megencephaly, developmental delay, lipomatosis, and speckled penis. PS and PSL had never been associated with risk of malignancy. Finding germline PTEN mutations in patients with BRRS, PS, and PSL suggests equivalent risks of developing malignancy as in CS with implications for medical management. The mutational spectra of CS and BRRS overlap, with many of the mutations occurring in exons 5, 7, and 8. Genotype-phenotype association analyses have revealed that the presence of germline PTEN mutations is associated with breast tumor development, and that mutations occurring within and 5' of the phosphatase motif were associated with multi-organ involvement. Pooled analysis of PTEN mutation series of CS and BRRS occurring in the last five years reveals that 65% of CS-associated mutations occur in the first five exons encoding the phosphatase domain and the promoter region, while 60% of BRRS-associated mutations occur in the 3' four exons encoding mainly the C2 domain. Somatic PTEN mutations occur with a wide distribution of frequencies in sporadic primary tumors, with the highest frequencies in endometrial carcinomas and glioblastoma multiform. Several mechanisms of PTEN inactivation occur in primary malignancies derived from different tissues, but a favored mechanism appears to occur in a tissue-specific manner. Inappropriate subcellular compartmentalization and increased/decreased proteosome degradation may be two novel mechanisms of PTEN inactivation. Further functional work could reveal more effective means of molecular-directed therapy and prevention.
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Affiliation(s)
- Charis Eng
- Clinical Cancer Genetics Program and Human Cancer Genetics Program, Comprehensive Cancer Center, Division of Human Genetics, Department of Internal Medicine, The Ohio State University, Columbus, Ohio 43210, USA.
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283
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Strauss G, Knape I, Melzner I, Debatin KM. Constitutive caspase activation and impaired death-inducing signaling complex formation in CD95-resistant, long-term activated, antigen-specific T cells. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2003; 171:1172-82. [PMID: 12874203 DOI: 10.4049/jimmunol.171.3.1172] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Elimination of T cells during an immune response is mediated by activation-induced cell death (AICD) and CD95-mediated apoptosis. Chronic graft-vs-host disease and T cell-mediated autoimmune diseases are caused by the persistence of activated T cells that escaped tolerance induction by deletion or silencing. To mimic the in vivo situation of long-term activated T cells, we generated an in vitro system using HLA-A1-specific T cells, weekly restimulated by Ag. While short-term activated T cells (two to five rounds of stimulation) were CD95 sensitive and susceptible to AICD, T cells stimulated more than eight times acquired constitutive CD95 resistance and exhibited reduced AICD. Phenotypically, these long-term activated T cells could be identified as effector/memory T cells. The expression of the proforms of the CD95 receptor initiator caspases, caspase-8 and -10, and the effector caspase-3 was strongly decreased in these cells, and only active caspase fragments were detected. In contrast to short-term activated T cells, constitutive CD95 receptor clustering was observed on the cell surface, and caspase-8 was bound to the CD95 receptor in the absence of receptor triggering. After further cross-linking of CD95, additional formation of the death-inducing signaling complex (DISC) was strongly impaired. Reduced DISC formation in long-term activated T cells was associated with the loss of PTEN expression and the increased phosphorylation of protein kinase B. Inhibitors of phosphoinositol 3-kinase restored CD95 sensitivity and DISC formation in long-term activated T cells. These data suggest that defective CD95 signaling in effector/memory T cells may contribute to the apoptosis resistance toward physiological stimuli in T cells mediating tissue destruction in vivo.
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Affiliation(s)
- Gudrun Strauss
- University Children's Hospital and Institute of Pathology, University of Ulm, Ulm, Germany
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284
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Na SY, Patra A, Scheuring Y, Marx A, Tolaini M, Kioussis D, Hemmings BA, Hemmings B, Hünig T, Bommhardt U. Constitutively active protein kinase B enhances Lck and Erk activities and influences thymocyte selection and activation. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2003; 171:1285-96. [PMID: 12874217 DOI: 10.4049/jimmunol.171.3.1285] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Protein kinase B (PKB), a serine threonine kinase is critically involved in cellular proliferation and survival. To characterize its role in T cell development in vivo, we have analyzed transgenic mice that express a membrane-targeted constitutively active version of PKB (myr PKB) in thymocytes and peripheral T cells. We report that myr PKB renders proliferative responses of thymocytes more sensitive to TCR signals by increased and sustained activation of Src kinase Lck and the extracellular signal-regulated kinase/mitogen-activated protein kinase pathway. In addition, the proliferative response of myr PKB T cells is relatively independent of calcium mobilization and calcineurin activity. We also find that myr PKB enhances phosphorylation of glycogen synthase kinase 3, a negative regulator of NFAT and T cell activation, and the recruitment of the adapter protein Cbl-c. Interestingly, we demonstrate that upon TCR/CD3 stimulation of wild-type T cells PKB is translocated into lipid rafts, adding a new role for PKB in TCR-initiated signalosome formation in T cell activation. Localization of transgenic PKB in lipid rafts could contribute to the higher TCR sensitivity of myr PKB thymocytes which is reflected in an increase in positive selection toward the CD4 lineage and variable effects on negative selection depending on the model system analyzed. Thus, our observations clearly indicate a cross-talk between PKB and important signaling molecules downstream of TCR that modulate the thresholds of thymocyte selection and T cell activation.
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Affiliation(s)
- Shin-Young Na
- Institutes of Virology and Immunobiology, University of Würzburg, Würzburg, Germany
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285
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Abstract
Many studies have shown the central importance of the co-receptors CD28, inducible costimulatory molecule (ICOS) and cytotoxic T lymphocyte antigen 4 (CTLA4) in the regulation of many aspects of T-cell function. CD28 and ICOS have both overlapping and distinct functions in the positive regulation of T-cell responses, whereas CTLA4 negatively regulates the response. The signalling pathways that underlie the function of each of the co-receptors indicate their shared and unique properties and provide compelling hints of functions that are as yet uncovered. Here, we outline the shared and distinct signalling events that are associated with each of the co-receptors and provide unifying concepts that are related to signalling functions of these co-receptors.
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Affiliation(s)
- Christopher E Rudd
- Molecular Immunology Section, Department of Immunology, Division of Investigative Science, Faculty of Medicine, Imperial College London, Hammersmith Hospital, Du Cane Road, London W12 ONN, UK.
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286
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Affiliation(s)
- S Lawman
- University College London, London, UK.
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287
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Ricci R, Komminoth P, Bannwart F, Torhorst J, Wight E, Heitz PU, Caduff RF. PTEN as a molecular marker to distinguish metastatic from primary synchronous endometrioid carcinomas of the ovary and uterus. DIAGNOSTIC MOLECULAR PATHOLOGY : THE AMERICAN JOURNAL OF SURGICAL PATHOLOGY, PART B 2003; 12:71-8. [PMID: 12766611 DOI: 10.1097/00019606-200306000-00002] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The distinction between two primary carcinomas on the one hand and a metastatic disease on the other hand in patients suffering from synchronous endometrioid carcinomas of the uterus and ovary is difficult. Exclusive histopathologic analysis appears to be insufficient and sometimes misleading. The tumor suppressor PTEN was found to be important in early neoplastic transformation in endometrioid carcinomas of the uterus. In this study, we screened synchronous endometrioid carcinomas of the uterus and ovary of 10 patients for loss of heterozygosity using seven different microsatellite markers at 10q23.3 and for mutations in the entire coding region of PTEN. Point mutations or microdeletions/insertions were found in six patients. Allelic loss at 10q23.3 was detected in eight patients. Based on conventional histology, a metastatic disease was diagnosed in seven patients and a concomitant uterine and ovarian carcinoma in three patients. After molecular analysis, the histopathologic diagnosis of three patients had to be revised. Histopathology represents the standard method to process tumor specimens from these patients. Nevertheless, mutation screen for PTEN and LOH analysis at 10q23.3 provide helpful genetic tools to establish a correct final diagnosis, which is important in view of prognosis and therapeutic implications.
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Affiliation(s)
- Romeo Ricci
- Department of Pathology, University Hospital of Zurich, Schmelzbergstrasse 12, CH-8091 Zurich, Switzerland
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288
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Ramírez-Sandoval R, Sánchez-Rodríguez SH, Herrera-van Oostdam D, Avalos-Díaz E, Herrera-Esparza R. Antinuclear antibodies recognize cellular autoantigens driven by apoptosis. Joint Bone Spine 2003; 70:187-94. [PMID: 12814761 DOI: 10.1016/s1297-319x(03)00019-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
OBJECTIVE Present study addresses the issue whether cellular antigens recognised by antinuclear autoantibodies are driven by apoptosis. MATERIALS AND METHODS HEp-2 cells were committed to apoptosis by camptothecin; DNA fragmentation and FasL and Bax expression monitored apoptosis. Autoantigens were probed by indirect immunofluorescence and Western blot with autoantibodies or monoclonals against: DNA, Ro60, La, U1-RNP, CENP-B, DNA Topoisomerase I, Jo-1 and NuMA. A comparison of antinuclear antibody reactivity between living and apoptotic cells was performed by ELISA. RESULTS Apoptotic changes such as chromatin fragmentation, blebs and apoptotic bodies were induced with 20 mM camptothecin. Autoantigens were better detected in apoptotic cells. U1-RNP, Jo1, DNA-Topoisomerase I, CENP-B and NuMA exhibited fragmentation and redistribution as a consequence of apoptosis; in contrast, Ro60 and La ribonucleoproteins did not show proteolysis. Additionally the ELISA titers of antinuclear antibodies were higher in apoptotic cells than in normal cells. CONCLUSION Apoptosis induces molecular changes in different autoantigens, this modification increases the antigen-driven response of autoantibodies such as anti-RNP, anti-DNA Topoisomerase I, anti-CENP-B and anti-Jo1. Apoptotic changes would contribute to break down the tolerance in autoimmune connective tissue disease.
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Affiliation(s)
- Roxana Ramírez-Sandoval
- Department of Molecular Biology, Centro de Biología Experimental, Universidad Autónoma de Zacatecas, Chepinque 306, Col. Lomas de la Soledad, 98040, Zacatecas, Mexico
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289
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Gary DS, Mattson MP. PTEN regulates Akt kinase activity in hippocampal neurons and increases their sensitivity to glutamate and apoptosis. Neuromolecular Med 2003; 2:261-9. [PMID: 12622404 DOI: 10.1385/nmm:2:3:261] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The tumor suppressor phosphatase PTEN can promote apoptosis of mitotic cells by inhibiting activation of the cell survival kinase Akt. PTEN is essential for normal embryonic development, PTEN expression is associated with neuronal differentiation, and deletion of PTEN in the mouse brain results in seizures, ataxia, and other abnormalities. However, the possible roles of PTEN in regulating neuronal survival are not known. We provide evidence that PTEN sensitizes hippocampal neurons to excitotoxic death in culture and in vivo. Overexpression of wild-type PTEN decreased, while a dominant-negative PTEN increased, levels of activated Akt in cultured hippocampal neurons. Wild-type PTEN promoted, while dominant-negative PTEN prevented, apoptotic death of neurons exposed to the excitatory amino acid neurotransmitter glutamate. Hippocampal neurons of mice with reduced PTEN levels were more resistant to seizure-induced death compared to wild-type littermates. These findings demonstrate a cell death function of PTEN in hippocampal neurons and identify PTEN as a potential therapeutic target for neurodegenerative disorders that involve excitotoxicity and apoptosis. The ability of PTEN to modify neuronal sensitivity to glutamate also suggests possible roles for PTEN in regulating developmental and synaptic plasticity.
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Affiliation(s)
- Devin S Gary
- Laboratory of Neurosciences, National Institute on Aging Gerontology Research Center, 5600 Nathan Shock Drive, Baltimore, MD 21224, USA
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290
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Dianzani U, Chiocchetti A, Ramenghi U. Role of inherited defects decreasing Fas function in autoimmunity. Life Sci 2003; 72:2803-24. [PMID: 12697265 DOI: 10.1016/s0024-3205(03)00196-6] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Fas is a death receptor belonging to the TNFR superfamily and induces cell apoptosis by both activating a caspase cascade and altering mitochondria. In the immune system, Fas is involved in the switching-off of the immune responses and cell mediated cytotoxicity. In humans, genetic defects decreasing Fas function cause the Autoimmune Lymphoproliferative Syndrome (ALPS) where autoimmunities are associated with accumulation of polyclonal lymphocytes in the secondary lymphoid tissues and expansion of T cells lacking both CD4 and CD8 (DN cells). Expansion of DN cells is absent in an ALPS variant, named Dianzani's Autoimmune Lymphoproliferative Disease (DALD). The observation that DALD patients' families display increased frequency of autoimmune diseases different from ALPS suggests that defects of Fas function may also play a role in development of "common" autoimmune diseases. This possibility is supported by detection of defective Fas function in substantial proportions of patients with the multiple autoimmune syndrome or aggressive forms of type 1 diabetes or multiple sclerosis. This article reviews data suggesting that development of autoimmune/lymphoproliferative patterns may involve several alterations hitting the Fas system, but might also involve alterations in other systems contributing to the switching-off or proliferation of lymphocytes.
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Affiliation(s)
- Umberto Dianzani
- Interdisciplinary Research Center of Autoimmune Diseases (IRCAD) and Department of Medical Sciences, "A. Avogadro" University of Eastern Piedmont, Via Solaroli 17, 28100, Novara, Italy.
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291
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Davis LS. A question of transformation: the synovial fibroblast in rheumatoid arthritis. THE AMERICAN JOURNAL OF PATHOLOGY 2003; 162:1399-402. [PMID: 12707022 PMCID: PMC1851189 DOI: 10.1016/s0002-9440(10)64272-1] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Affiliation(s)
- Laurie S Davis
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA.
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292
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Dustin ML. Regulation of T cell migration through formation of immunological synapses: the stop signal hypothesis. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2003; 512:191-201. [PMID: 12405204 DOI: 10.1007/978-1-4615-0757-4_25] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- Michael L Dustin
- Program in Molecular Pathogenesis and Department of Pathology, Skirball Institute of Molecular Medicine, New York University School of Medicine, NY 10016, USA
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293
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Stilo R, Liguoro D, di Jeso B, Leonardi A, Vito P. The alpha-chain of the nascent polypeptide-associated complex binds to and regulates FADD function. Biochem Biophys Res Commun 2003; 303:1034-41. [PMID: 12684039 DOI: 10.1016/s0006-291x(03)00487-x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
FADD protein is a critical mediator of signal transduction pathways activated by several members of the TNF-receptor gene superfamily. Recently, an induced proximity model has been proposed to interpret FADD-mediated signaling events. According to this model, FADD facilitates signaling by inducing clusters of effector molecules in proximity of the activated receptor complex. An important corollary of the induced-proximity model is that FADD protein should not form oligomers in the absence of receptor stimulation. Here we show that, in the absence of death receptor stimulation, FADD is found associated to the alpha chain of the nascent polypeptide-associated complex (NAC). Exposure to TNF results in disruption of FADD/NAC complex. Expression of NAC regulates formation of FADD oligomers and modulates FADD-mediated signaling. Thus, our observation indicates that NAC may serve as an intracellular regulator of FADD function.
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Affiliation(s)
- Romania Stilo
- BioGeM Consortium, Università degli Studi di Napoli Federico II, Via Sergio Pansini 5, Italy
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294
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Byun DS, Cho K, Ryu BK, Lee MG, Park JI, Chae KS, Kim HJ, Chi SG. Frequent monoallelic deletion of PTEN and its reciprocal associatioin with PIK3CA amplification in gastric carcinoma. Int J Cancer 2003; 104:318-27. [PMID: 12569555 DOI: 10.1002/ijc.10962] [Citation(s) in RCA: 152] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Mutational alterations of PTEN and PIK3CA, which negatively and positively regulate PI3-kinase activity, respectively, have been observed in many types of human cancer. To explore the implication of PTEN and PIK3CA mutations in gastric tumorigenesis, we characterized the expression and mutation status of the genes in 126 gastric tissues and 15 cell lines. Expression of PTEN transcript was abnormally low in 5 of 15 (33%) cell lines and 20 of 55 (36%) primary carcinomas, whereas 0 of 71 noncancerous tissues including 16 benign tumors showed altered expression. Allelotyping analysis using an intragenic polymorphism (IVS4+109) revealed that 14 of 30 (47%) informative cases carried LOH of the gene, which is closely linked to low expression. The LOH rate was significantly higher in advanced tumors [12 of 19 (63%)] compared to early-stage tumors [2 of 11 (18%)] and more frequent in poorly differentiated tumors [9 of 13 (69%)] than well- or moderately differentiated tumors [5 of 17 (29%)]. Interestingly, however, none of the LOH tumors carried mutational disruption of the remaining allele, suggesting haploinsufficiency of PTEN in gastric tumorigenesis. Methylation studies revealed that PTEN pseudogene, but not PTEN, is methylated in cell lines and primary tumors, indicating that PTEN is not a target of epigenetic silencing in gastric cancers and that the pseudogene should be considered more carefully in methylation analysis of the PTEN promoter. Genomic amplification of PIK3CA was found in 9 of 15 (60%) cell lines and 20 of 55 (36.4%) primary tumors but in no noncancerous tissues. Furthermore, PIK3CA amplification was predominantly detected in tumors with no PTEN alterations, suggesting that mutations of PTEN and PIK3CA are mutually exclusive events in gastric tumorigenesis. Amplification of PIK3CA was strongly associated with increased expression of PIK3CA transcript and elevated levels of phospho-AKT. Collectively, our data reveal that 13 of 15 (87%) gastric cell lines and 31 of 55 (56%) primary carcinomas harbored either amplification of PIK3CA or abnormal reduction of PTEN. Mutually exclusive alterations of PTEN and PIK3CA also suggest that mutations of either gene could activate the PI3-kinase/AKT signaling pathway, which is directly linked to the malignant progression of gastric tumor cells.
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Affiliation(s)
- Do-Sun Byun
- Department of Pathology, College of Medicine, Kyung Hee University, Seoul, Korea
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295
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Okkenhaug K, Vanhaesebroeck B. PI3K in lymphocyte development, differentiation and activation. Nat Rev Immunol 2003; 3:317-30. [PMID: 12669022 DOI: 10.1038/nri1056] [Citation(s) in RCA: 605] [Impact Index Per Article: 28.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Phosphoinositide 3-kinases (PI3Ks) regulate numerous biological processes, including cell growth, differentiation, survival, proliferation, migration and metabolism. In the immune system, impaired PI3K signalling leads to immunodeficiency, whereas unrestrained PI3K signalling contributes to autoimmunity and leukaemia. New insights into the role of PI3Ks in lymphocyte biology have been derived from gene-targeting studies, which have identified the PI3K subunits that are involved in B-cell and T-cell signalling. In particular, the catalytic subunit p110delta seems to be adapted to transmit antigen-receptor signalling in B and T cells. Additional recent work has provided new insights into the molecular interactions that lead to PI3K activation and the signalling pathways that are regulated by PI3K.
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Affiliation(s)
- Klaus Okkenhaug
- Molecular Immunology Programme, The Babraham Institute, Cambridge CB2 4AT, UK.
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296
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Kane LP, Weiss A. The PI-3 kinase/Akt pathway and T cell activation: pleiotropic pathways downstream of PIP3. Immunol Rev 2003; 192:7-20. [PMID: 12670391 DOI: 10.1034/j.1600-065x.2003.00008.x] [Citation(s) in RCA: 210] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Ligation of the T cell receptor for antigen (TCR) and/or costimulatory receptor CD28 results in rapid activation of phosphoinositide-3 kinase (PI-3 kinase). It remains unclear, however, precisely how this activation occurs and also how the newly generated phospholipid products trigger the various events associated with T cell activation. Here we discuss the current understanding of how PI-3 kinase is activated by the TCR and CD28 and what roles its products play in T cell activation. We also review recent advances in understanding the function of Akt in particular, especially its role in CD28 costimulation. Several functional targets of Akt are discussed in this regard: inducible transcription, cell survival, glucose metabolism, and the cellular translational machinery. These pathways have been associated with TCR/CD28 costimulation, and they have also been implicated as targets of Akt.
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Affiliation(s)
- Lawrence P Kane
- Department of Medicine, The Howard Hughes Medical Institute, University of California, San Francisco, CA 94143, USA
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297
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Seminario MC, Wange RL. Lipid phosphatases in the regulation of T cell activation: living up to their PTEN-tial. Immunol Rev 2003; 192:80-97. [PMID: 12670397 DOI: 10.1034/j.1600-065x.2003.00013.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The initiating events associated with T activation in response to stimulation of the T cell antigen receptor (TCR) and costimulatory receptors, such as CD28, are intimately associated with the enzymatically catalyzed addition of phosphate not only to key tyrosine, threonine and serine residues in proteins but also to the D3 position of the myo-inositol ring of phosphatidylinositol (PtdIns). This latter event is catalyzed by the lipid kinase phosphoinositide 3-kinase (PI3K). The consequent production of PtdIns(3,4)P2 and PtdIns(3,4,5)P3 serves both to recruit signaling proteins to the plasma membrane and to induce activating conformational changes in proteins that contain specialized domains for the binding of these phospholipids. The TCR signaling proteins that are subject to regulation by PI3K include Akt, phospholipase Cgamma1 (PLCgamma1), protein kinase C zeta (PKC-zeta), Itk, Tec and Vav, all of which play critical roles in T cell activation. As is the case for phosphorylation of protein substrates, the phosphorylation of PtdIns is under dynamic regulation, with the D3 phosphate being subject to hydrolysis by the 3-phosphatase PTEN (phosphatase and tensin homolog deleted on chromosome 10), thereby placing PTEN in direct opposition to PI3K. In this review we consider recent data concerning how PTEN may act in regulating the process of T cell activation.
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Affiliation(s)
- Maria-Cristina Seminario
- Laboratory of Cellular and Molecular Biology, National Institutes on Aging/IRP/NIH/DHHS, Baltimore, MD 21224, USA.
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298
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Abstract
Mcl-1 is a critical antiapoptotic survival factor for human multiple myeloma (MM). We examined the importance of IL-6 for Mcl-1 expression in five MM cell lines and in primary MM cells from 14 patients. While culture of MM.1S cells in IL-6 did induce Mcl-1 expression, four other MM cell lines exhibited high levels of Mcl-1 expression that were unaffected by IL-6. Similarly, Mcl-1 expression in 10 of 14 primary MM isolates was found to be IL-6-independent. An analysis of the mechanisms responsible for IL-6-independent Mcl-1 expression was undertaken. ERK1/2 activity did not influence Mcl-1 expression, distinct from Mcl-1 regulation that occurs during myeloid differentiation from hematopoietic progenitor cells. Inhibition of the PI3K pathway led to growth inhibition of 8226 and ANBL-6 cells without reduction of Mcl-1 levels, and high level Mcl-1 expression was maintained in the absence of activated STAT3. Analysis of the transcriptional activity of 5'-regulatory sequences from the human Mcl-1 gene in MM cells demonstrated high levels of IL-6-independent indicator gene activation as predicted. These data demonstrate that the mechanisms regulating Mcl-1 levels in MM cells are heterogeneous, and are often independent from IL-6 signaling pathways.
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Affiliation(s)
- Bin Zhang
- University of Maryland Greenebaum Cancer Center, Baltimore 21201, USA
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299
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Suzuki A, Kaisho T, Ohishi M, Tsukio-Yamaguchi M, Tsubata T, Koni PA, Sasaki T, Mak TW, Nakano T. Critical roles of Pten in B cell homeostasis and immunoglobulin class switch recombination. J Exp Med 2003; 197:657-67. [PMID: 12615906 PMCID: PMC2193827 DOI: 10.1084/jem.20021101] [Citation(s) in RCA: 185] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Pten is a tumor suppressor gene mutated in human cancers. We used the Cre-loxP system to generate a B cell-specific mutation of Pten in mice (bPten(flox/flox)mice). bPten(flox/flox) mice showed elevated numbers of B1a cells and increased serum autoantibodies. Among B2 cells in bPten(flox/flox) spleens, numbers of marginal zone B (MZB) cells were significantly increased while those of follicular B (FOB) cells were correspondingly decreased. Pten-deficient B cells hyperproliferated, were resistant to apoptotic stimuli, and showed enhanced migration. The survival kinase PKB/Akt was highly activated in Pten-deficient splenic B cells. In addition, immunoglobulin class switch recombination was defective and induction of activation-induced cytidine deaminase (AID) was impaired. Thus, Pten plays a role in developmental fate determination of B cells and is an indispensable regulator of B cell homeostasis.
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Affiliation(s)
- Akira Suzuki
- Department of Molecular Cell Biology, Research Institute for Microbial Disease, Osaka University, Osaka 565-0871, Japan
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300
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Sun J, Matthias G, Mihatsch MJ, Georgopoulos K, Matthias P. Lack of the transcriptional coactivator OBF-1 prevents the development of systemic lupus erythematosus-like phenotypes in Aiolos mutant mice. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2003; 170:1699-706. [PMID: 12574333 DOI: 10.4049/jimmunol.170.4.1699] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Here we show that mice lacking the zinc finger transcription factor Aiolos develop the symptoms of human systemic lupus erythematosus (SLE), which is characterized by the production of anti-dsDNA Ab and immune complex-mediated glomerulonephritis. This finding indicates that normal Aiolos function is necessary to maintain immune homeostasis and suppress the development of systemic autoimmune disease and implicates Aiolos as a possible candidate gene for SLE. Interestingly, Aiolos-null mice can no longer mount autoimmune reactions and completely fail to develop SLE when they are deficient for the B cell-specific transcription coactivator OBF-1. The lack of OBF-1 reverses several Aiolos mutant mouse phenotypes, such as B cell hyperproliferation, high expression of activation marker on B cells, and spontaneous germinal center formation. Unexpectedly, B cell development at the immature B cell stage is severely impaired in the bone marrow of Aiolos/OBF-1 double-deficient mice, demonstrating the key role of these factors in the transition from pre-B to immature B cells. Our results indicate that B cells play a crucial role in the development of SLE in Aiolos mutant mice and might be useful for the strategy of SLE treatment.
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Affiliation(s)
- Jian Sun
- Friedrich Miescher Institute for Biomedical Research, Novartis Research Foundation, Basel, Switzerland
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