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Hernandez-Martinez JM, Rosell R, Arrieta O. Somatic and germline ATM variants in non-small-cell lung cancer: Therapeutic implications. Crit Rev Oncol Hematol 2023:104058. [PMID: 37343657 DOI: 10.1016/j.critrevonc.2023.104058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Accepted: 06/16/2023] [Indexed: 06/23/2023] Open
Abstract
ATM is an apical kinase of the DNA damage response involved in the repair of DNA double-strand breaks. Germline ATM variants (gATM) have been associated with an increased risk of developing lung adenocarcinoma (LUAD), and approximately 9% of LUAD tumors harbor somatic ATM mutations (sATM). Biallelic carriers of pathogenic gATM exhibit a plethora of immunological abnormalities, but few studies have evaluated the contribution of immune dysfunction to lung cancer susceptibility. Indeed, little is known about the clinicopathological characteristics of lung cancer patients with sATM or gATM alterations. The introduction of targeted therapies and immunotherapies, and the increasing number of clinical trials evaluating treatment combinations, warrants a careful reexamination of the benefits and harms that different therapeutic approaches have had in lung cancer patients with sATM or gATM. This review will discuss the role of ATM in the pathogenesis of lung cancer, highlighting potential therapeutic approaches to manage ATM-deficient lung cancers.
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Affiliation(s)
- Juan-Manuel Hernandez-Martinez
- Thoracic Oncology Unit and Experimental Oncology Laboratory, Instituto Nacional de Cancerología de México (INCan); CONACYT-Instituto Nacional de Cancerología, Mexico City, Mexico
| | - Rafael Rosell
- Institut d'Investigació en Ciències Germans Trias i Pujol, Badalona, Spain; (4)Institut Català d'Oncologia, Hospital Germans Trias i Pujol, Badalona, Spain
| | - Oscar Arrieta
- Thoracic Oncology Unit and Experimental Oncology Laboratory, Instituto Nacional de Cancerología de México (INCan).
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Pal P, Mahadevappa M, Kamble N, Santhosh Kumar DV, Yadav R, Netravathi M. A clinical profile of 100 patients with ataxia telangiectasia seen at a tertiary care center. ANNALS OF MOVEMENT DISORDERS 2020. [DOI: 10.4103/aomd.aomd_28_19] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
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3
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The Role for the DSB Response Pathway in Regulating Chromosome Translocations. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2018; 1044:65-87. [PMID: 29956292 DOI: 10.1007/978-981-13-0593-1_6] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
In response to DNA double strand breaks (DSB), mammalian cells activate the DNA Damage Response (DDR), a network of factors that coordinate their detection, signaling and repair. Central to this network is the ATM kinase and its substrates at chromatin surrounding DSBs H2AX, MDC1 and 53BP1. In humans, germline inactivation of ATM causes Ataxia Telangiectasia (A-T), an autosomal recessive syndrome of increased proneness to hematological malignancies driven by clonal chromosomal translocations. Studies of cancers arising in A-T patients and in genetically engineered mouse models (GEMM) deficient for ATM and its substrates have revealed complex, multilayered roles for ATM in translocation suppression and identified functional redundancies between ATM and its substrates in this context. "Programmed" DSBs at antigen receptor loci in developing lymphocytes employ ubiquitous DDR factors for signaling and repair and have been particularly useful for mechanistic studies because they are region-specific and can be monitored in vitro and in vivo. In this context, murine thymocytes deficient for ATM recapitulate the molecular events that lead to transformation in T cells from A-T patients and provide a widely used model to study the mechanisms that suppress RAG recombinase-dependent translocations. Similarly, analyses of the fate of Activation induced Cytidine Deaminase (AID)-dependent DSBs during mature B cell Class Switch Recombination (CSR) have defined the genetic requirements for end-joining and translocation suppression in this setting. Moreover, a unique role for 53BP1 in the promotion of synapsis of distant DSBs has emerged from these studies.
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Robust reprogramming of Ataxia-Telangiectasia patient and carrier erythroid cells to induced pluripotent stem cells. Stem Cell Res 2016; 17:296-305. [DOI: 10.1016/j.scr.2016.08.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Revised: 07/29/2016] [Accepted: 08/06/2016] [Indexed: 12/18/2022] Open
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Jones MR, Huang JC, Chua SY, Baillie DL, Rose AM. The atm-1 gene is required for genome stability in Caenorhabditis elegans. Mol Genet Genomics 2012; 287:325-35. [PMID: 22350747 PMCID: PMC3313021 DOI: 10.1007/s00438-012-0681-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2011] [Accepted: 02/04/2012] [Indexed: 10/28/2022]
Abstract
The Ataxia-telangiectasia-mutated (ATM) gene in humans was identified as the basis of a rare autosomal disorder leading to cancer susceptibility and is now well known as an important signal transducer in response to DNA damage. An approach to understanding the conserved functions of this gene is provided by the model system, Caenorhabditis elegans. In this paper we describe the structure and loss of function phenotype of the ortholog atm-1. Using bioinformatic and molecular analysis we show that the atm-1 gene was previously misannotated. We find that the transcript is in fact a product of three gene predictions, Y48G1BL.2 (atm-1), K10E9.1, and F56C11.4 that together make up the complete coding region of ATM-1. We also characterize animals that are mutant for two available knockout alleles, gk186 and tm5027. As expected, atm-1 mutant animals are sensitive to ionizing radiation. In addition, however, atm-1 mutants also display phenotypes associated with genomic instability, including low brood size, reduced viability and sterility. We document several chromosomal fusions arising from atm-1 mutant animals. This is the first time a mutator phenotype has been described for atm-1 in C. elegans. Finally we demonstrate the use of a balancer system to screen for and capture atm-1-derived mutational events. Our study establishes C. elegans as a model for the study of ATM as a mutator potentially leading to the development of screens to identify therapeutic targets in humans.
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Affiliation(s)
- Martin R. Jones
- Department of Medical Genetics, University of British Columbia, 419-2125 East Mall, Vancouver, BC V6T 1Z4 Canada
| | - Jim Chin Huang
- Department of Medical Genetics, University of British Columbia, 419-2125 East Mall, Vancouver, BC V6T 1Z4 Canada
| | - Shu Yi Chua
- Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, BC V5A 1S6 Canada
| | - David L. Baillie
- Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, BC V5A 1S6 Canada
| | - Ann M. Rose
- Department of Medical Genetics, University of British Columbia, 419-2125 East Mall, Vancouver, BC V6T 1Z4 Canada
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Deng W, Tsao SW, Mak GWY, Tsang CM, Ching YP, Guan XY, Huen MSY, Cheung ALM. Impact of G₂ checkpoint defect on centromeric instability. Oncogene 2010; 30:1281-9. [PMID: 21057540 DOI: 10.1038/onc.2010.508] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Centromeric instability is characterized by dynamic formation of centromeric breaks, deletions, isochromosomes and translocations, which are commonly observed in cancer. So far, however, the mechanisms of centromeric instability in cancer cells are still poorly understood. In this study, we tested the hypothesis that G(2) checkpoint defect promotes centromeric instability. Our observations from multiple approaches consistently support this hypothesis. We found that overexpression of cyclin B1, one of the pivotal genes driving G(2) to M phase transition, impaired G(2) checkpoint and promoted the formation of centromeric aberrations in telomerase-immortalized cell lines. Conversely, centromeric instability in cancer cells was ameliorated through reinforcement of G(2) checkpoint by cyclin B1 knockdown. Remarkably, treatment with KU55933 for only 2.5 h, which abrogated G(2) checkpoint, was sufficient to produce centromeric aberrations. Moreover, centromeric aberrations constituted the major form of structural abnormalities in G(2) checkpoint-defective ataxia telangiectasia cells. Statistical analysis showed that the frequencies of centromeric aberrations in G(2) checkpoint-defective cells were always significantly overrepresented compared with random assumption. As there are multiple pathways leading to G(2) checkpoint defect, our finding offers a broad explanation for the common occurrence of centromeric aberrations in cancer cells.
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Affiliation(s)
- W Deng
- Department of Anatomy, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, SAR, China
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Nahas SA, Gatti RA. DNA double strand break repair defects, primary immunodeficiency disorders, and 'radiosensitivity'. Curr Opin Allergy Clin Immunol 2009; 9:510-6. [PMID: 19858715 DOI: 10.1097/aci.0b013e328332be17] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
PURPOSE OF REVIEW It is important to assess 'radiosensitivity' in patients suspected of immunodeficiency because underlying DNA double strand break (DSB) repair defects have considerable impact on V(D)J recombination, class switching and lymphocyte maturation, leading to increased infections and cancer risk. In addition, the phenotype of 'radiosensitivity' may identify patients with increased toxicity to radiation and chemotherapeutic agents and could impact upon their preparation for stem cell transplantation. To date, the gold standard for evaluating 'radiosensitivity' has been the colony-survival assay (CSA), which reflects the efficiency of DNA repair of DSBs as it impacts upon replication and cell survival. Other methods measure other aspects of DNA repair; however, their limited specificity often leads to false negatives for predicting 'radiosensitivity', especially clinical radiosensitivity. Lastly, clinical awareness of an overarching syndrome of DSB repair disorders, XCIND, could help to raise diagnostic levels of suspicion and, thereby, identify additional patients with new forms of immunodeficiency, cancer susceptibility and radiosensitivity. RECENT FINDINGS Within the past year, three new radiosensitivity disorders of DSB repair have been described, involving deficiencies of RNF168, RAD50, and DNA-PKcs. These are truly translational advances because they validate laboratory models and allow new patients to be identified. SUMMARY Recognizing compromised genome stability is important but difficult. We review the evidence for correlations between DSB repair, abnormal colony formation, clinical radiosensitivity and other laboratory methods.
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Affiliation(s)
- C.M.R. Weemaes
- Department of Pediatrics, University Hospital Nijmegen, PO Box 9101, 6500HB, Nijmegen, The Netherlands
| | - D.F.C.M. Smeets
- Department of Human Genetics, University Hospital Nijmegen, PO Box 9101, 6500HB, Nijmegen, The Netherlands
| | - C.J.A.M. van der Burgt
- Department of Pediatrics, University Hospital Nijmegen, PO Box 9101, 6500HB, Nijmegen, The Netherlands
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Iourov IY, Vorsanova SG, Liehr T, Kolotii AD, Yurov YB. Increased chromosome instability dramatically disrupts neural genome integrity and mediates cerebellar degeneration in the ataxia-telangiectasia brain. Hum Mol Genet 2009; 18:2656-69. [PMID: 19414482 DOI: 10.1093/hmg/ddp207] [Citation(s) in RCA: 102] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Ataxia telangiectasia (AT) is a chromosome instability (CIN) neurological syndrome arising from DNA damage response defects due to ATM gene mutations. The hallmark of AT is progressive cerebellar degeneration. However, the intrinsic cause of the neurodegeneration remains poorly understood. To highlight the relationship between CIN and neurodegeneration in AT, we monitored aneuploidy and interphase chromosome breaks (chromosomal biomarkers of genomic instability) in the normal and diseased brain. We observed a 2-3-fold increase of stochastic aneuploidy affecting different chromosomes in the cerebellum and the cerebrum of the AT brain. The global aneuploidization of the brain is, therefore, a new genetic phenomenon featuring AT. Degenerating cerebellum in AT was remarkably featured by a dramatic 5-20-fold increase of non-random DNA double-strand breaks and aneuploidy affecting chromosomes 14 and, to a lesser extend, chromosomes 7 and X. Novel recurrent chromosome hot spots associated with cerebellar degeneration were mapped within 14q12. In silico analysis has revealed that this genomic region contains two candidate genes (FOXG1B and NOVA1). The existence of non-random breaks disrupting specific chromosomal loci in neural cells with DNA repair deficiency supports the hypothesis that neuronal genome may undergo programmed somatic rearrangements. Investigating chromosome integrity in neural cells, we provide the first evidence that increased CIN can result into neurodegeneration, whereas it is generally assumed to be associated with cancer. Our data suggest that mosaic instability of somatic genome in cells of the central nervous system is more significant genetic factor predisposing to the brain pathology than previously recognized.
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Affiliation(s)
- Ivan Y Iourov
- National Research Center of Mental Health, Russian Academy of Medical Sciences, Zagorodnoe sh. 2, Moscow 119152, Russia
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Moin M, Aghamohammadi A, Kouhi A, Tavassoli S, Rezaei N, Ghaffari SR, Gharagozlou M, Movahedi M, Purpak Z, Mirsaeid Ghazi B, Mahmoudi M, Farhoudi A. Ataxia-telangiectasia in Iran: clinical and laboratory features of 104 patients. Pediatr Neurol 2007; 37:21-8. [PMID: 17628218 DOI: 10.1016/j.pediatrneurol.2007.03.002] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/21/2006] [Revised: 01/04/2007] [Accepted: 03/05/2007] [Indexed: 11/30/2022]
Abstract
Ataxia-telangiectasia is a multisystem disorder characterized by progressive neurologic impairment, variable immunodeficiency, impaired organ maturation, x-ray hypersensitivity, oculocutaneous telangiectasia, and a predisposition to malignancy. To evaluate clinical and immunologic features of Iranian patients with ataxia-telangiectasia, the records of 104 patients with ataxia-telangiectasia (54 male, 50 female) with the age range of 1.6-23.5 years were reviewed. The Iranian Primary Immunodeficiency Registry was used as the data source. Progressive ataxia was seen in all the patients. Other symptoms were eye movement disorders (n = 84), slurred speech (n = 70), mental retardation (n = 10), and ocular (n = 87) and cutaneous (n = 73) telangiectasia. Three patients developed leukemia and lymphoma, and 17 patients had family history of malignancy. Positive correlation was seen between clinical immunologic symptoms and immunoglobulin deficiencies (P = 0.004). The predominant infections were sinopulmonary and acute and recurrent infections (78 cases). Infections included pneumonia (56 patients), otitis media (34 patients), and sinusitis (50 patients). Average serum alpha-fetoprotein level was 149 +/- 137 ng/dL. The incidence of ataxia-telangiectasia in Iran is high, possibly due to familial marriages. Treatment should be focused on supportive management to prolong survival.
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Affiliation(s)
- Mostafa Moin
- Department of Allergy and Clinical Immunology, Children's Medical Center, and Immunology, Asthma and Allergy Research Institute, Tehran, Iran
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Ouyang Y, Kwon YT, An JY, Eller D, Tsai SC, Diaz-Perez S, Troke JJ, Teitell MA, Marahrens Y. Loss of Ubr2, an E3 ubiquitin ligase, leads to chromosome fragility and impaired homologous recombinational repair. Mutat Res 2006; 596:64-75. [PMID: 16488448 DOI: 10.1016/j.mrfmmm.2005.12.016] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2005] [Revised: 12/05/2005] [Accepted: 12/21/2005] [Indexed: 01/08/2023]
Abstract
The N-end rule pathway of protein degradation targets proteins with destabilizing N-terminal residues. Ubr2 is one of the E3 ubiquitin ligases of the mouse N-end rule pathway. We have previously shown that Ubr2-/- male mice are infertile, owing to the arrest of spermatocytes between the leptotene/zygotene and pachytene of meiosis I, the failure of chromosome pairing, and subsequent apoptosis. Here, we report that mouse fibroblast cells derived from Ubr2-/- embryos display genome instability. The frequency of chromosomal bridges and micronuclei were much higher in Ubr2-/- fibroblasts than in +/+ controls. Metaphase chromosome spreads from Ubr2-/- cells revealed a high incidence of spontaneous chromosomal gaps, indicating chromosomal fragility. These fragile sites were generally replicated late in S phase. Ubr2-/- cells were hypersensitive to mitomycin C, a DNA cross-linking agent, but displayed normal sensitivity to gamma-irradiation. A reporter assay showed that Ubr2-/- cells are significantly impaired in the homologous recombination repair of a double strand break. In contrast, Ubr2-/- cells appeared normal in an assay for non-homologous end joining. Our results therefore unveil the role of the ubiquitin ligase Ubr2 in maintaining genome integrity and in homologous recombination repair.
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Affiliation(s)
- Yan Ouyang
- Department of Human Genetics, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
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12
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Ouyang Y, Salstrom J, Diaz-Perez S, Nahas S, Matsuno Y, Dawson D, Teitell MA, Horvath S, Riggs AD, Gatti RA, Marahrens Y. Inhibition of Atm and/or Atr disrupts gene silencing on the inactive X chromosome. Biochem Biophys Res Commun 2005; 337:875-80. [PMID: 16213462 DOI: 10.1016/j.bbrc.2005.09.122] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2005] [Accepted: 09/16/2005] [Indexed: 01/02/2023]
Abstract
ATM and ATR are well documented for their roles in maintaining the integrity of genomic DNA by responding to DNA damage and preparing the cell for repair. Since ATM and ATR have been reported to exist in complexes with histone deacetylases, we asked whether Atm and Atr might also uphold gene silencing by heterochromatin. We show that the Atm/Atr inhibitor 2-aminopurine causes the inactive X chromosome to accumulate abnormal chromatin and undergo unwanted gene reactivation. We provide evidence that this gene expression from the inactive X chromosome is not a byproduct of the accumulation of DNA breaks. Individually inhibiting Atm and Atr by either small interfering RNA or the expression of dominant-negative ATM and ATR constructs also compromised X-inactivation. Atm and Atr, therefore, not only function in responding to DNA damage but perhaps also are involved in gene silencing via the maintenance of heterochromatin.
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Affiliation(s)
- Yan Ouyang
- Department of Human Genetics, The David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
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Winrow CJ, Pankratz DG, Vibat CRT, Bowen TJ, Callahan MA, Warren AJ, Hilbush BS, Wynshaw-Boris A, Hasel KW, Weaver Z, Lockhart DJ, Barlow C. Aberrant recombination involving the granzyme locus occurs in Atm-/- T-cell lymphomas. Hum Mol Genet 2005; 14:2671-84. [PMID: 16087685 DOI: 10.1093/hmg/ddi301] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Ataxia telangiectasia (A-T) is an autosomal recessive disease caused by loss of function of the serine/threonine protein kinase ATM (ataxia telangiectasia mutated). A-T patients have a 250-700-fold increased risk of developing lymphomas and leukemias which are typically highly invasive and proliferative. In addition, a subset of adult acute lymphoblastic leukemias and aggressive B-cell chronic lymphocytic leukemias that occur in the general population show loss of heterozygosity for ATM. To define the specific role of ATM in lymphomagenesis, we studied T-cell lymphomas isolated from mice with mutations in ATM and/or p53 using cytogenetic analysis and mRNA transcriptional profiling. The analyses identified genes misregulated as a consequence of the amplifications, deletions and translocation events arising as a result of ATM loss. A specific recurrent disruption of the granzyme gene family locus was identified resulting in an aberrant granzyme B/C fusion product. The combined application of cytogenetic and gene expression approaches identified specific loci and genes that define the pathway of initiation and progression of lymphoreticular malignancies in the absence of ATM.
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Affiliation(s)
- Christopher J Winrow
- The Salk Institute for Biological Studies, The Laboratory of Genetics, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA
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Chun HH, Castellví-Bel S, Wang Z, Nagourney RA, Plaeger S, Becker-Catania SG, Naeim F, Sparkes RS, Gatti RA. TCL-1, MTCP-1 and TML-1 gene expression profile in non-leukemic clonal proliferations associated with ataxia-telangiectasia. Int J Cancer 2002; 97:726-31. [PMID: 11857346 DOI: 10.1002/ijc.10102] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
We analyzed the role of 4 genes, TCL-1, MTCP-1, TML-1 and ATM, in the early pathogenesis of T cell leukemia, with particular interest in the characteristics of long-standing non-leukemic clonal proliferations in ataxia-telangiectasia (A-T) patients. Five patients were studied: 4 patients had A-T (2 of whom had non-leukemic clonal proliferations [ATCP]), 1 had B cell lymphoma and 1 had T-ALL; a fifth patient with T-PLL did not have A-T. We measured the levels of expression for TCL-1, MTCP-1 and TML-1. TCL-1, not expressed in unstimulated mature T cells, was upregulated in the peripheral blood leukocytes (PBL) of the 2 A-T patients with ATCP. It was also expressed in the malignant cells of the A-T patient with B cell lymphoma and the T-PLL cells of the patient without A-T. In the same cells, MTCP-1 type A was expressed equally in all 5 patients, as well as in the controls; MTCP-1 type B transcripts were not observed. TML-1, also not expressed in unstimulated T cells, was expressed in the PBL of one A-T patient with ATCP and in the leukemic cells of the non-A-T T-PLL patient. These expression patterns were compared to cellular immunophenotypes. The non-leukemic clonal T cell populations had the characteristics of immature T cells. We conclude that TCL-1 and TML-1 play a role in cell proliferation and survival but are not pivotal genes in the progression to malignancy, even when the ATM gene is mutated. Additional genetic alterations must occur to initiate tumorigenesis.
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Affiliation(s)
- Helen H Chun
- Department of Pathology, School of Medicine, University of California at Los Angeles, Los Angeles, CA 90095-1732, USA
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Regueiro JR, Porras O, Lavin M, Gatti RA. ATAXIA-TELANGIECTASIA. Radiol Clin North Am 2000. [DOI: 10.1016/s0033-8389(22)00186-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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Grant SG, Reeger W, Wenger SL. Diagnosis of ataxia telangiectasia with the glycophorin A somatic mutation assay. GENETIC TESTING 1999; 1:261-7. [PMID: 10464655 DOI: 10.1089/gte.1997.1.261] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
There are no widely applied definitive laboratory tests for the diagnosis of ataxia telangiectasia (AT). We, and others, have previously reported significantly elevated levels of in vivo somatic mutation in blood samples from known AT patients, observations that might form the basis for a useful prospective laboratory test for confirmation of a clinical diagnosis of AT. In the present case, a 4 1/2-year-old black female was suspected of having AT based on ataxic gait and chronic upper respiratory infections. Blood work-up showed low IgG2 and elevated alpha-fetoprotein (AFP), consistent with the AT phenotype. Her peripheral blood karyotype was normal, however, with no spontaneous breakage observed among 100 solid stained metaphases. Lymphocytes from AT patients often show elevated levels of chromosome rearrangement, especially at sites of immunoglobulin and T-cell receptor genes. Therefore, a blood sample was analyzed with the glycophorin A (GPA) in vivo somatic mutation assay. The GPA assay detects and quantifies the phenotypically variant erythrocytes resulting from loss of heterozygosity for the MN blood group. The patient had a 10-fold increased frequency of variant erythrocytes with a phenotype consistent with simple loss of the N allele, which is characteristic of AT. In addition, the variant cell distribution for this patient showed three other, more qualitative hallmarks of AT: a normal frequency of allele loss and duplication events, a unique ridge of cells of intermediate phenotype between the normal and mutant peaks, and evidence of similar ongoing mutational loss of the M allele. Together with clinical data, these distinctive qualitative and quantitative features of the GPA assay allow for a diagnosis of AT with a projected accuracy of 95%. Therefore, we suggest that the GPA assay, which can be performed on < 1 ml of blood and completed in less than a day, be considered as a confirmatory laboratory test for a clinical diagnosis of AT.
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Affiliation(s)
- S G Grant
- Center for Environmental and Occupational Health and Toxicology, University of Pittsburgh, PA 15238, USA
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Shammas MA, Shmookler Reis RJ. Recombination and its roles in DNA repair, cellular immortalization and cancer. AGE 1999; 22:71-88. [PMID: 23604399 PMCID: PMC3455241 DOI: 10.1007/s11357-999-0009-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Genetic recombination is the creation of new gene combinations in a cell or gamete, which differ from those of progenitor cells or parental gametes. In eukaryotes, recombination may occur at mitosis or meiosis. Mitotic recombination plays an indispensable role in DNA repair, which presumably directed its early evolution; the multiplicity of recombination genes and pathways may be best understood in this context, although they have acquired important additional functions in generating diversity, both somatically (increasing the immune repertoire) and in germ line (facilitating evolution). Chromosomal homologous recombination and HsRad51 recombinase expression are increased in both immortal and preimmortal transformed cells, and may favor the occurrence of multiple oncogenic mutations. Tumorigenesis in vivo is frequently associated with karyotypic instability, locus-specific gene rearrangements, and loss of heterozygosity at tumor suppressor loci - all of which can be recombinationally mediated. Genetic defects which increase the rate of somatic mutation (several of which feature elevated recombination) are associated with early incidence and high risk for a variety of cancers. Moreover, carcinogenic agents appear to quite consistently stimulate homologous recombination. If cells with high recombination arise, either spontaneously or in response to "recombinogens," and predispose to the development of cancer, what selective advantage could favor these cells prior to the occurrence of growth-promoting mutations? We propose that the augmentation of telomere-telomere recombination may provide just such an advantage, to hyper-recombinant cells within a population of telomerase-negative cells nearing their replicative (Hayflick) limit, by extending telomeres in some progeny cells and thus allowing their continued proliferation.
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Affiliation(s)
- Masood A. Shammas
- />Dept. of Geriatrics, University of Arkansas for Medical Sciences, USA
- />J.L. McClellan Veterans Medical Center — Research 151, 4300 West 7th Street, Little Rock, AR 72205
| | - Robert J. Shmookler Reis
- />Dept. of Geriatrics, University of Arkansas for Medical Sciences, USA
- />Dept. of Biochemistry & Molecular Biology, University of Arkansas for Medical Sciences, USA
- />Dept. of Medicine, University of Arkansas for Medical Sciences, USA
- />J.L. McClellan Veterans Medical Center — Research 151, 4300 West 7th Street, Little Rock, AR 72205
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Yuille MA, Coignet LJ. The ataxia telangiectasia gene in familial and sporadic cancer. Recent Results Cancer Res 1999; 154:156-73. [PMID: 10026998 DOI: 10.1007/978-3-642-46870-4_9] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
The ataxia telangiectasia (A-T) gene, ATM, predisposes affected homozygotes to a wide range of malignancies. It has been suggested that this is a consequence of the genomic instability associated with the syndrome. The elevated risk of malignancy is not, however, observed among A-T heterozygotes (except, apparently, regarding breast cancer). In this report we describe results from the study of the rare sporadic disease, T cell prolymphocytic leukaemia (T-PLL). In all individuals tested, we observed that at least one ATM allele was disrupted by rearrangement, that in many cases both alleles were disrupted and that there were additional mutations, predominantly missense, that clustered toward the 3' end of the gene corresponding to the protein's phosphatidylinositol 3-kinase (PIK)-related domain. We conclude that the ATM gene can act as a tumour suppressor in the development of sporadic T-PLL. Our finding of a surfeit of mutations within ATM may reflect the involvement of the gene at more than one step in tumorigenesis. In particular, we suggest that the clustering of missense mutations may pertain to the late-onset character of both sporadic and A-T-related T-PLL, since the closest homologue of Atm protein is the yeast TEL1 protein that maintains telomere length. ATM inactivation may not be the initiating event in T-PLL tumorigenesis: prior mutation of another gene--perhaps TCL1 activation--may be obligate. This would explain the recessive character of T-PLL risk in A-T.
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Affiliation(s)
- M A Yuille
- Department of Haematology and Cytogenetics, Haddow Laboratories, Sutton, Surrey, UK
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20
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Brown KD, Ziv Y, Sadanandan SN, Chessa L, Collins FS, Shiloh Y, Tagle DA. The ataxia-telangiectasia gene product, a constitutively expressed nuclear protein that is not up-regulated following genome damage. Proc Natl Acad Sci U S A 1997; 94:1840-5. [PMID: 9050866 PMCID: PMC20004 DOI: 10.1073/pnas.94.5.1840] [Citation(s) in RCA: 116] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
The product of the ataxia-telangiectasia gene (ATM) was identified by using an antiserum developed to a peptide corresponding to the deduced amino acid sequence. The ATM protein is a single, high-molecular weight protein predominantly confined to the nucleus of human fibroblasts, but is present in both nuclear and microsomal fractions from human lymphoblast cells and peripheral blood lymphocytes. ATM protein levels and localization remain constant throughout all stages of the cell cycle. Truncated ATM protein was not detected in lymphoblasts from ataxia-telangiectasia patients homozygous for mutations leading to premature protein termination. Exposure of normal human cells to gamma-irradiation and the radiomimetic drug neocarzinostatin had no effect on ATM protein levels, in contrast to a noted rise in p53 levels over the same time interval. These findings are consistent with a role for the ATM protein in ensuring the fidelity of DNA repair and cell cycle regulation following genome damage.
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Affiliation(s)
- K D Brown
- Laboratory of Gene Transfer, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD 20892, USA
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21
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Tupler R, Marseglia GL, Stefanini M, Prosperi E, Chessa L, Nardo T, Marchi A, Maraschio P. A variant of the Nijmegen breakage syndrome with unusual cytogenetic features and intermediate cellular radiosensitivity. J Med Genet 1997; 34:196-202. [PMID: 9132489 PMCID: PMC1050892 DOI: 10.1136/jmg.34.3.196] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
We report the first Italian case of Nijmegen breakage syndrome (NBS). The proband is an immunodeficient, microcephalic, 11 year old boy with a "bird-like" face. He developed a T cell rich B cell lymphoma. Spontaneous chromosomal instability was detected in T and B lymphocytes and fibroblasts; chromosomes 7 and 14 were only sporadically involved in the rearrangements and no clonal abnormality was present. The patient appeared to be sensitive both to ionising radiation and to bleomycin, although his sensitivity did not reach the level of AT reference cells. After bleomycin treatment, inhibition of DNA synthesis was low when compared with normal cells, but higher than observed in an AT reference strain. Moreover, cell cycle analysis, after drug exposure, showed a progressive reduction in the percentage of S phase cells, but the G1 arrest, found in normal cells, was not observed. On clinical evaluation our patient shares features with NBS subjects, but cytogenetic and cell biological data do not completely overlap with those reported in Nijmegen breakage syndrome. The ethnic origin of our patient might account for these differences, as expression of different allelic forms at the NBS locus.
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22
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Affiliation(s)
- M S Meyn
- Department of Genetics, Yale University School of Medicine, New Haven, CT 06510, USA
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23
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Abstract
Chromosomal instability with a high frequency of telomere fusion is characteristic of ataxia-telangiectasia cells both in vivo and in vitro. We have measured telomere length and found it to be consistently reduced in both diploid and SV40-transformed cells A-T fibroblasts, relative to control cells. We examined a few possible mechanisms which might account for telomeric length reduction, including telomerase activity in transformed cells and endogenous nuclease activities, but found no differences between A-T and control cells in these parameters.
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Affiliation(s)
- S J Xia
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock 72205, USA
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24
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Metcalfe JA, Parkhill J, Campbell L, Stacey M, Biggs P, Byrd PJ, Taylor AM. Accelerated telomere shortening in ataxia telangiectasia. Nat Genet 1996; 13:350-3. [PMID: 8673136 DOI: 10.1038/ng0796-350] [Citation(s) in RCA: 236] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Ataxia telangiectasia (AT) is characterized by neurological deterioration, immunodeficiency, spontaneous chromosomal instability, hypersensitivity to ionizing radiation, predisposition to cancer, particularly T cell leukaemia and lymphoma, and premature ageing. The most commonly observed defect affecting telomeres in humans is telomeric fusions, particularly in T lymphocytes in AT patients. Rarely, some tumour cells, like senescent cells, have dicentric chromosomes that may arise as a result of telomeric sequence loss. We show that the AT mutation in the homozygous state confers a predisposition to accelerated telomere shortening with increasing age in peripheral blood lymphocytes (PBLs), which may be linked to premature senescence. We also show that telomeric fusions are associated with large (> 90%) preleukaemic translocation clones in T cells. We propose that these fusions may result from a compound effect of accelerated telomere shortening, together with a growth advantage of cells in large clones which leads to further telomere loss. Fusions are not observed in leukaemic cells in these patients. There is no evidence that either accelerated telomere loss per se or telomeric fusions are important in tumourigenesis. Telomerase is present in both normal and AT lymphocytes and so neither telomere shortening nor telomeric fusions can be explained by the absence of telomerase.
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Affiliation(s)
- J A Metcalfe
- CRC Institute for Cancer Studies, Medical School, University of Birmingham, UK
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25
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26
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Willems PJ, Van Roy BC, Kleijer WJ, Van der Kraan M, Martin JJ. Atypical clinical presentation of ataxia telangiectasia. AMERICAN JOURNAL OF MEDICAL GENETICS 1993; 45:777-82. [PMID: 8456862 DOI: 10.1002/ajmg.1320450624] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Ataxia telangiectasia (AT) is an autosomal recessive disorder characterized by progressive cerebellar ataxia, oculocutaneous telangiectasias, immunodeficiency with recurrent infections, IgA and IgE deficiency, and increased incidence of malignancies. The pathognomonic biological abnormalities consist of spontaneous chromosomal instability resulting in a high in vivo occurrence of cells with translocations, especially involving chromosomes 7 and 14, and a relative insensitivity of DNA replication in vitro to radiation exposure. We report on a patient with the biological hallmarks of AT but with atypical clinical manifestations. Although progressive cerebellar ataxia was present, the neurological picture was broader than that usually seen in AT and included peripheral polyneuropathy and spinal atrophy. On the other hand, telangiectasias, recurrent infections, malignancies, IgA deficiency, or other immunological abnormalities were not present. This illustrates that the clinical picture of AT is broad and nonspecific, and highlights the diagnostic value of cytogenetic analysis and studies of radioresistance of DNA synthesis.
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Affiliation(s)
- P J Willems
- Department of Medical Genetics, University of Antwerp-UIA, Belgium
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27
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Lipkowitz S, Garry VF, Kirsch IR. Interlocus V-J recombination measures genomic instability in agriculture workers at risk for lymphoid malignancies. Proc Natl Acad Sci U S A 1992; 89:5301-5. [PMID: 1608939 PMCID: PMC49279 DOI: 10.1073/pnas.89.12.5301] [Citation(s) in RCA: 68] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
V(D)J [variable-(diversity)-joining] rearrangements occur between, as well as within, immune receptor loci, resulting in the generation of hybrid antigen-receptor genes and the formation of a variety of lymphocyte-specific chromosomal aberrations. Such hybrid genes occur at a low frequency in the peripheral blood lymphocytes (PBL) of normal individuals but show a markedly increased incidence in the PBL of individuals with the autosomal recessive disease ataxia-telangiectasia. In this manuscript we demonstrate that the frequency of hybrid antigen-receptor genes is 10- to 20-fold increased in the PBL of an occupational group, agriculture workers, with related environmental exposures. Both ataxia-telangiectasia patients and this population of agriculture workers are at increased risk for lymphoid malignancy. This result suggests that the measurement of hybrid antigen receptor-genes in PBL may be a sensitive assay for a type of lymphocyte-specific genomic instability. As a corollary, this assay may identify populations at risk of developing common types of lymphoid malignancy.
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Affiliation(s)
- S Lipkowitz
- National Cancer Institute-Navy Medical Oncology Branch, Bethesda Naval Hospital, MD 20889-5105
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28
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Gatti RA. Speculations on the ataxia-telangiectasia defect. CLINICAL IMMUNOLOGY AND IMMUNOPATHOLOGY 1991; 61:S10-5. [PMID: 1718644 DOI: 10.1016/s0090-1229(05)80032-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Ataxia-telangiectasia (A-T) is inherited as an monogenetic autosomal recessive disease. Ataxia appears around 1 year of age and progresses until the patient becomes wheelchair-bound, usually by age 10. This progress correlates with deterioration of Purkinje cells in the cerebellum. Sinopulmonary infections are common in patients from some countries but not others. One-third of the patients develop a neoplasm, usually lymphoid, sometime during their shortened lives. Conventional doses of radiation therapy for such cancers are contraindicated since A-T patients are hypersensitive to ionizing radiation. Five complementation groups have been described, based on correction of radioresistant DNA synthesis of fused fibroblasts from pairs of patients. Chromosomal translocations are found in 5-10% of peripheral T cells from most patients and the translocation breakpoints involve sites of normal somatic DNA rearrangement. Thus, the A-T gene(s) effects several cell lineages, suggesting that it is a "housekeeping" gene. Other speculations on "candidate genes" are considered. Recent progress localizing A-T to chromosome 11q23 is reviewed.
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Affiliation(s)
- R A Gatti
- UCLA School of Medicine, Department of Pathology 90024
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29
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Kojis TL, Gatti RA, Sparkes RS. The cytogenetics of ataxia telangiectasia. CANCER GENETICS AND CYTOGENETICS 1991; 56:143-56. [PMID: 1756458 DOI: 10.1016/0165-4608(91)90164-p] [Citation(s) in RCA: 104] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Ataxia-telangiectasia (AT) is a heterogeneous autosomal recessive disorder marked by cerebellar ataxia, oculocutaneous telangiectases, hypersensitivity to ionizing radiation, immunodeficiency, and cancer susceptibility. AT is also a spontaneous chromosomal breakage syndrome, notable for tissue-specific cytogenetic changes and telomeric fusions. Molecular characterization of rearrangements specific to T-lymphocytes suggests that a DNA repair/processing defect is potentially responsible for the diverse array of chromosomal abnormalities observed in a variety of AT cell types.
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Affiliation(s)
- T L Kojis
- Jules Stein Eye Institute, Los Angeles, CA 90024-7008
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30
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Mouchet F, Ninane J, Gosseye S, Verellen C, Bonnier C, Evrard P, Vermylen C, Scheiff JM, Cornu G. Leiomyoma of the suprarenal gland in a child with ataxia-telangiectasia. Pediatr Hematol Oncol 1991; 8:235-41. [PMID: 1742182 DOI: 10.3109/08880019109033457] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
We report the occurrence of a leiomyoma of the suprarenal gland in a 10-year-old girl with ataxia-telangiectasia (A-T). Muscle cell tumors are very uncommon in this gland as they are in A-T. Possible reasons for developing nonhematologic tumors in this syndrome are reviewed. A defect in DNA repair mechanisms probably favors, in young children, the expression of tumors normally expected in the aged.
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Affiliation(s)
- F Mouchet
- Department of Paediatric Haematology and Oncology, Cliniques Universitaires St Luc, Brussels, Belgium
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31
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Waghray M, Gascon GG, al-Sedairy S, Hannan MA. Cytogenetic investigations in three cell types of a Saudi family with ataxia telangiectasia. Hum Genet 1991; 87:285-9. [PMID: 1864602 DOI: 10.1007/bf00200905] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Chromosomal analyses were performed on lymphocytes, fibroblasts and lymphoblastoid cell lines derived from a Saudi family with ataxia telangiectasia (AT). The three siblings of a consanguineous marriage were all affected. The lymphocytes of the AT homozygotes (probands) showed an increase of 2- to 6-fold and 4- to 8-fold respectively, in the frequency of spontaneous and X-ray-induced chromosomal aberrations compared with controls, while the parents (obligate heterozygotes) of the patients showed no notable difference. The unirradiated lymphocytes from the oldest AT sibling, an 11-year-old boy (AT1), showed specific rearrangements involving chromosomes 7 and 14 [t(7;14)(q35;q12)] and 12 and 14 [t(12;14)(q23;q12)] in two different clones. The most severely affected sibling was a 9-year-old girl (AT2) who presented with a clone showing a novel rearrangement involving chromosomes 14 and 17, namely: del(14) (q31q32) and dup(17)(q21-q24). The lymphocytes from the third sibling, a 2-year-old boy (AT3), showed a t(2;14)(p24;q12). In addition, an inv(14)(q12q32) was observed in all three AT patients, while inv(7)(p14q35) was found only in patients 2 and 3. The lymphocytes from the AT parents and controls showed normal karyotypes. The breakpoints involving chromosomes 2, 12 and 17, observed in our studies, have rarely been reported in other series of AT patients. No non-random chromosomal rearrangements were observed either in the skin fibroblasts or in the lymphoblastoid cell lines derived from the AT patients, although all cell lines showed an increase in both spontaneous and radiation-induced chromosomal breaks per cell. The present study constitutes the first report on a cytogenetic analysis of a Saudi family with three AT siblings.
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Affiliation(s)
- M Waghray
- Biological and Medical Research, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia
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32
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Pawlak AL, Ignatowicz R. Unaltered cell proliferation rate of the ataxia telangiectasia lymphocytes dividing in vitro. Immunol Invest 1991; 20:169-72. [PMID: 1864635 DOI: 10.3109/08820139109050784] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Lower cell density was found in cultures of ataxia telangiectasia lymphocytes as compared to control lymphocyte cultures. This fits with the earlier observations of decreased incorporation of 3H-Thymidine into lymphocytes of ataxia telangiectasia (AT) patients. However, the finding that there was no significant difference in proliferation rate index between AT and control cultures was unexpected. This may indicate that both cell count and measurements of thymidine incorporation in lymphocyte cultures characterize cell populations distinct from that of proliferating cells.
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Affiliation(s)
- A L Pawlak
- Institute of Human Genetics, Polish Academy of Sciences, Poznań
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33
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34
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Gatti RA. Localizing the genes for ataxia-telangiectasia: a human model for inherited cancer susceptibility. Adv Cancer Res 1991; 56:77-104. [PMID: 2028843 DOI: 10.1016/s0065-230x(08)60478-9] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- R A Gatti
- Department of Pathology, University of California, Los Angeles School of Medicine 90024
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35
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McConville CM, Formstone CJ, Hernandez D, Thick J, Taylor AM. Fine mapping of the chromosome 11q22-23 region using PFGE, linkage and haplotype analysis; localization of the gene for ataxia telangiectasia to a 5cM region flanked by NCAM/DRD2 and STMY/CJ52.75, phi 2.22. Nucleic Acids Res 1990; 18:4335-43. [PMID: 1975092 PMCID: PMC331249 DOI: 10.1093/nar/18.15.4335] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Using pulsed-field gel electrophoresis, and a range of different enzyme digests, we have established that both markers of each of the pairs CJ52.208/YNB3.12, NCAM/DRD2, and STMY/CJ52.75, on chromosome 11q22-23, show physical linkage on a single DNA fragment. We have also shown, using genetic linkage and haplotype analyses, that these markers lie within a region of approximately 18cM, which, it has been shown previously, is likely to contain the A-T gene. The relative positions of these marker loci, and the distance between them was determined in order to construct a detailed map which has allowed a more precise localization of the A-T gene. We have shown that in pairwise linkage analysis the strongest support for linkage to the A-T gene was with the STMY/CJ52.75 locus (Z = 5.59, theta = 0.0). A three-point analysis using the results from STMY/CJ52.75 and the closely linked marker phi 2.22 gave Z = 5.55, theta = 0.03. Despite persisting evidence of some linkage to Thy-1 our results are consistent with the existence of a single A-T locus on chromosome 11q22-23 and our best estimate of the position of this locus places it between NCAM/DRD2 and (STMY/CJ52.75, F2.22) (Z = 6.74), a region of approximately 5cM in males.
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Affiliation(s)
- C M McConville
- Department of Cancer Studies, University of Birmingham, UK
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36
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Lipkowitz S, Stern MH, Kirsch IR. Hybrid T cell receptor genes formed by interlocus recombination in normal and ataxia-telangiectasis lymphocytes. J Exp Med 1990; 172:409-18. [PMID: 1695665 PMCID: PMC2188320 DOI: 10.1084/jem.172.2.409] [Citation(s) in RCA: 103] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
In this paper, using polymerase chain reaction (PCR), we demonstrated the occurrence of hybrid genes formed by interlocus recombination between T cell receptor gamma (TCR-gamma) variable (V) regions and TCR-beta joining (J) regions in the peripheral blood lymphocytes (PBL) from normal individuals and patients with ataxia-telangiectasia (AT). Sequence analysis of the PCR-derived hybrid genes confirmed that site-specific V gamma-J beta recombination had occurred and showed that 10 of 23 genomic hybrid genes maintained a correct open reading frame. By dilution analysis, the frequency of these hybrid genes was 8 +/- 1/10(5) cells in normal PBL and 587 +/- 195/10(5) cells in AT PBL. These frequencies and the approximately 70-fold difference between the normal and AT samples are consistent with previous cytogenetic data examining the occurrence of an inversion of chromosome 7 in normal and AT PBL. We also demonstrated expression of these hybrid genes by PCR analysis of first-strand cDNA prepared from both normal and AT PBL. Sequence analysis of the PCR-amplified transcripts showed that, in contrast to the genomic hybrid genes, 19 of 22 expressed genes maintained a correct open reading frame at the V-J junction and correctly spliced the hybrid V-J exon to a TCR-beta constant region, thus allowing translation into a potentially functional hybrid TCR protein. Another type of hybrid TCR transcript was found in a which a rearranged TCR-gamma V-J exon was correctly spliced to a TCR-beta constant region. This form of hybrid gene may be formed by trans-splicing. These hybrid TCR genes may serve to increase the repertoire of the immune response. In addition, studies of their mechanism of formation and its misregulation in AT may provide insight into the nature of the chromosomal instability syndrome associated with AT. The mechanism underlying hybrid gene formation may be analogous to the mechanism underlying rearrangements between putative growth-affecting genes and the antigen receptor loci, which are associated with AT lymphocyte clones and lymphoid malignancies.
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Affiliation(s)
- S Lipkowitz
- Navy Medical Oncology Branch, Naval Hospital, National Cancer Institute, Bethesda, Maryland
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