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Abdulmawjood B, Costa B, Roma-Rodrigues C, Baptista PV, Fernandes AR. Genetic Biomarkers in Chronic Myeloid Leukemia: What Have We Learned So Far? Int J Mol Sci 2021; 22:12516. [PMID: 34830398 PMCID: PMC8626020 DOI: 10.3390/ijms222212516] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Revised: 11/11/2021] [Accepted: 11/18/2021] [Indexed: 12/20/2022] Open
Abstract
Chronic Myeloid Leukemia (CML) is a rare malignant proliferative disease of the hematopoietic system, whose molecular hallmark is the Philadelphia chromosome (Ph). The Ph chromosome originates an aberrant fusion gene with abnormal kinase activity, leading to the buildup of reactive oxygen species and genetic instability of relevance in disease progression. Several genetic abnormalities have been correlated with CML in the blast phase, including chromosomal aberrations and common altered genes. Some of these genes are involved in the regulation of cell apoptosis and proliferation, such as the epidermal growth factor receptor (EGFR), tumor protein p53 (TP53), or Schmidt-Ruppin A-2 proto-oncogene (SRC); cell adhesion, e.g., catenin beta 1 (CTNNB1); or genes associated to TGF-β, such as SKI like proto-oncogene (SKIL), transforming growth factor beta 1 (TGFB1) or transforming growth factor beta 2 (TGFB2); and TNF-α pathways, such as Tumor necrosis factor (TNFA) or Nuclear factor kappa B subunit 1 (NFKB1). The involvement of miRNAs in CML is also gaining momentum, where dysregulation of some critical miRNAs, such as miRNA-451 and miRNA-21, which have been associated to the molecular modulation of pathogenesis, progression of disease states, and response to therapeutics. In this review, the most relevant genomic alterations found in CML will be addressed.
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Affiliation(s)
- Bilal Abdulmawjood
- i4HB—Institute for Health and Bioeconomy, NOVA School of Science and Technology, NOVA University Lisbon, 2819-516 Caparica, Portugal; (B.A.); (B.C.); (C.R.-R.)
- UCIBIO—Applied Molecular Biosciences Unit, Department of Life Sciences, NOVA School of Science and Technology, NOVA University Lisbon, 2819-516 Caparica, Portugal
| | - Beatriz Costa
- i4HB—Institute for Health and Bioeconomy, NOVA School of Science and Technology, NOVA University Lisbon, 2819-516 Caparica, Portugal; (B.A.); (B.C.); (C.R.-R.)
- UCIBIO—Applied Molecular Biosciences Unit, Department of Life Sciences, NOVA School of Science and Technology, NOVA University Lisbon, 2819-516 Caparica, Portugal
| | - Catarina Roma-Rodrigues
- i4HB—Institute for Health and Bioeconomy, NOVA School of Science and Technology, NOVA University Lisbon, 2819-516 Caparica, Portugal; (B.A.); (B.C.); (C.R.-R.)
- UCIBIO—Applied Molecular Biosciences Unit, Department of Life Sciences, NOVA School of Science and Technology, NOVA University Lisbon, 2819-516 Caparica, Portugal
| | - Pedro V. Baptista
- i4HB—Institute for Health and Bioeconomy, NOVA School of Science and Technology, NOVA University Lisbon, 2819-516 Caparica, Portugal; (B.A.); (B.C.); (C.R.-R.)
- UCIBIO—Applied Molecular Biosciences Unit, Department of Life Sciences, NOVA School of Science and Technology, NOVA University Lisbon, 2819-516 Caparica, Portugal
| | - Alexandra R. Fernandes
- i4HB—Institute for Health and Bioeconomy, NOVA School of Science and Technology, NOVA University Lisbon, 2819-516 Caparica, Portugal; (B.A.); (B.C.); (C.R.-R.)
- UCIBIO—Applied Molecular Biosciences Unit, Department of Life Sciences, NOVA School of Science and Technology, NOVA University Lisbon, 2819-516 Caparica, Portugal
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Nogueira BMD, Machado CB, Montenegro RC, DE Moraes MEA, Moreira-Nunes CA. Telomere Length and Hematological Disorders: A Review. In Vivo 2020; 34:3093-3101. [PMID: 33144412 DOI: 10.21873/invivo.12142] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Revised: 08/06/2020] [Accepted: 08/10/2020] [Indexed: 12/22/2022]
Abstract
Telomeres compose the end portions of human chromosomes, and their main function is to protect the genome. In hematological disorders, telomeres are shortened, predisposing to genetic instability that may cause DNA damage and chromosomal rearrangements, inducing a poor clinical outcome. Studies from 2010 to 2019 were compiled and experimental studies using samples of patients diagnosed with hematological malignancies that reported the size of the telomeres were described. Abnormal telomere shortening is described in cancer, but in hematological neoplasms, telomeres are still shortened even after telomerase reactivation. In this study, we compared the sizes of telomeres in leukemias, myelodysplastic syndrome and lymphomas, identifying that the smallest telomeres are present in patients at relapse. In conclusion, the experimental and clinical data analyzed in this review demonstrate that excessive telomere shortening is present in major hematological malignancies and its analysis and measurement is a crucial step in determining patient prognosis, predicting disease risk and assisting in the decision for targeted therapeutic strategies.
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Affiliation(s)
- Beatriz Maria Dias Nogueira
- Pharmacogenetics Laboratory, Drug Research and Development Center (NPDM), Department of Physiology and Pharmacology, Federal University of Ceará, Fortaleza, CE, Brazil
| | - Caio Bezerra Machado
- Pharmacogenetics Laboratory, Drug Research and Development Center (NPDM), Department of Physiology and Pharmacology, Federal University of Ceará, Fortaleza, CE, Brazil
| | - Raquel Carvalho Montenegro
- Pharmacogenetics Laboratory, Drug Research and Development Center (NPDM), Department of Physiology and Pharmacology, Federal University of Ceará, Fortaleza, CE, Brazil
| | - Maria Elisabete Amaral DE Moraes
- Pharmacogenetics Laboratory, Drug Research and Development Center (NPDM), Department of Physiology and Pharmacology, Federal University of Ceará, Fortaleza, CE, Brazil
| | - Caroline Aquino Moreira-Nunes
- Pharmacogenetics Laboratory, Drug Research and Development Center (NPDM), Department of Physiology and Pharmacology, Federal University of Ceará, Fortaleza, CE, Brazil
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Differential Regulation of Telomeric Complex by BCR-ABL1 Kinase in Human Cellular Models of Chronic Myeloid Leukemia-From Single Cell Analysis to Next-Generation Sequencing. Genes (Basel) 2020; 11:genes11101145. [PMID: 33003326 PMCID: PMC7601685 DOI: 10.3390/genes11101145] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2020] [Revised: 09/15/2020] [Accepted: 09/25/2020] [Indexed: 11/17/2022] Open
Abstract
Telomeres are specialized nucleoprotein complexes, localized at the physical ends of chromosomes, that contribute to the maintenance of genome stability. One of the features of chronic myeloid leukemia (CML) cells is a reduction in telomere length which may result in increased genomic instability and progression of the disease. Aberrant telomere maintenance in CML is not fully understood and other mechanisms such as the alternative lengthening of telomeres (ALT) are involved. In this work, we employed five BCR-ABL1-positive cell lines, namely K562, KU-812, LAMA-84, MEG-A2, and MOLM-1, commonly used in the laboratories to study the link between mutation, copy number, and expression of telomere maintenance genes with the expression, copy number, and activity of BCR-ABL1. Our results demonstrated that the copy number and expression of BCR-ABL1 are crucial for telomere lengthening. We observed a correlation between BCR-ABL1 expression and telomere length as well as shelterins upregulation. Next-generation sequencing revealed pathogenic variants and copy number alterations in major tumor suppressors, such as TP53 and CDKN2A, but not in telomere-associated genes. Taken together, we showed that BCR-ABL1 kinase expression and activity play a crucial role in the maintenance of telomeres in CML cell lines. Our results may help to validate and properly interpret results obtained by many laboratories employing these in vitro models of CML.
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Telomere shortening correlates with leukemic stem cell burden at diagnosis of chronic myeloid leukemia. Blood Adv 2019; 2:1572-1579. [PMID: 29980572 DOI: 10.1182/bloodadvances.2018017772] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Accepted: 05/21/2018] [Indexed: 01/22/2023] Open
Abstract
Telomere length (TL) in peripheral blood (PB) cells of patients with chronic myeloid leukemia (CML) has been shown to correlate with disease stage, prognostic scores, response to therapy, and disease progression. However, due to considerable genetic interindividual variability, TL varies substantially between individuals, limiting its use as a robust prognostic marker in individual patients. Here, we compared TL of BCR-ABL-, nonleukemic CD34+CD38- hematopoietic stem cells (HSC) in the bone marrow of CML patients at diagnosis to their individual BCR-ABL+ leukemic stem cell (LSC) counterparts. We observed significantly accelerated telomere shortening in LSC compared with nonleukemic HSC. Interestingly, the degree of LSC telomere shortening was found to correlate significantly with the leukemic clone size. To validate the diagnostic value of nonleukemic cells as internal controls and to rule out effects of tyrosine kinase inhibitor (TKI) treatment on these nontarget cells, we prospectively assessed TL in 134 PB samples collected in deep molecular remission after TKI treatment within the EURO-SKI study (NCT01596114). Here, no significant telomere shortening was observed in granulocytes compared with an age-adjusted control cohort. In conclusion, this study provides proof of principle for accelerated telomere shortening in LSC as opposed to HSC in CML patients at diagnosis. The fact that the degree of telomere shortening correlates with leukemic clone's size supports the use of TL in leukemic cells as a prognostic parameter pending prospective validation. TL in nonleukemic myeloid cells seems unaffected even by long-term TKI treatment arguing against a reduction of telomere-mediated replicative reserve in normal hematopoiesis under TKI treatment.
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Gunes C, Avila AI, Rudolph KL. Telomeres in cancer. Differentiation 2017; 99:41-50. [PMID: 29291448 DOI: 10.1016/j.diff.2017.12.004] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2017] [Revised: 12/19/2017] [Accepted: 12/20/2017] [Indexed: 02/07/2023]
Abstract
Telomere shortening as a consequence of cell divisions during aging and chronic diseases associates with an increased cancer risk. Experimental data revealed that telomere shortening results in telomere dysfunction, which in turn affects tumorigenesis in two ways. First, telomere dysfunction suppresses tumor progression by the activation of DNA damage checkpoints, which induce cell cycle arrest (senescence) or apoptosis, as well as by inducing metabolic compromise and activation of immune responses directed against senescent cells. Second, telomere dysfunction promotes tumorigenesis by inducing chromosomal instability in tumor initiating cells, by inhibiting proliferative competition of non-transformed cells, and possibly, also by influencing tumor cell plasticity. The tumor promoting effects of telomere dysfunction are context dependent and require the loss of p53-dependent DNA damage checkpoints or other genetic modifiers that attenuate DNA damage responses possibly involving complex interactions of different genes. The activation of telomere stabilizing mechanisms appears as a subsequent step, which is required to enable immortal grotwh of emerging cancer cells. Here, we conceptually discuss our current knowledge and new, unpublished experimental data on telomere dependent influences on tumor initiation and progression.
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Affiliation(s)
| | - Alush Irene Avila
- Research Group on Stem Cell Aging, Leibniz Institute on Aging, Fritz Lipmann Institute (FLI), Beutenbergstr. 11, 07745 Jena, Germany
| | - K Lenhard Rudolph
- Research Group on Stem Cell Aging, Leibniz Institute on Aging, Fritz Lipmann Institute (FLI), Beutenbergstr. 11, 07745 Jena, Germany.
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Abstract
BACKGROUND Telomeres are protein DNA structures present at the ends of chromosomes and are essential for genetic stability and cell replication. Telomerase is the enzyme complex that maintains telomere integrity. Hematopoietic stem cells express telomerase and contain long telomeres, which become shorter as cells differentiate and mature. The extent of telomere shortening and the level of telomerase activity often correlate with the presence and severity of some hematopoietic diseases. METHODS The fundamentals of telomeres and telomerase are reviewed, and the telomere biology of human hematopoietic cells is discussed. RESULTS Telomere length and telomerase activity are important in the self-renewal of hematopoietic stem cells. Changes within these compartments affect both normal hematopoietic cells and the generation of hematopoietic disease. Telomere length provides information pertaining to the proliferative history and potential of a hematopoietic cell. CONCLUSIONS The role of telomerase and telomeres within the hematopoietic compartment needs further clarification. Advances in our knowledge in this field may improve clinical outcomes for the treatment of hematologic disease.
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Affiliation(s)
- Ngaire Elwood
- Leukaemia Research Fund Stem Cell Laboratory, Department of Clinical Haematology and Oncology, Murdoch Children's Research Institute, Melbourne, Australia.
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7
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Expression pattern of hTERT telomerase subunit gene in different stages of chronic myeloid leukemia. Mol Biol Rep 2014; 41:5557-61. [DOI: 10.1007/s11033-014-3472-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2014] [Accepted: 06/14/2014] [Indexed: 11/29/2022]
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Dynamic length changes of telomeres and their nuclear organization in chronic myeloid leukemia. Cancers (Basel) 2013; 5:1086-102. [PMID: 24202335 PMCID: PMC3795380 DOI: 10.3390/cancers5031086] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2013] [Revised: 08/08/2013] [Accepted: 08/16/2013] [Indexed: 01/11/2023] Open
Abstract
Chronic myeloid leukemia (CML) is a myeloproliferative neoplasm characterized by the t(9;22) translocation. As in most cancers, short telomeres are one of the features of CML cells, and telomere shortening accentuates as the disease progresses from the chronic phase to the blastic phase. Although most individual telomeres are short, some of them are lengthened, and long individual telomeres occur non-randomly and might be associated with clonal selection. Telomerase is the main mechanism used to maintain telomere lengths, and its activity increases when CML evolves toward advanced stages. ALT might be another mechanism employed by CML cells to sustain the homeostasis of their telomere lengths and this mechanism seems predominant at the early stage of leukemogenesis. Also, telomerase and ALT might jointly act to maintain telomere lengths at the chronic phase, and as CML progresses, telomerase becomes the major mechanism. Finally, CML cells display an altered nuclear organization of their telomeres which is characterized by the presence of high number of telomeric aggregates, a feature of genomic instability, and differential positioning of telomeres. CML represents a good model to study mechanisms responsible for dynamic changes of individual telomere lengths and the remodeling of telomeric nuclear organization throughout cancer progression.
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Telomere shortening in Ph-negative chronic myeloproliferative neoplasms: A biological marker of polycythemia vera and myelofibrosis, regardless of hydroxycarbamide therapy. Exp Hematol 2013; 41:627-34. [DOI: 10.1016/j.exphem.2013.03.007] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2012] [Revised: 03/17/2013] [Accepted: 03/19/2013] [Indexed: 02/08/2023]
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Abstract
Telomeres are long (TTAGGG)(n) nucleotide repeats and an associated protein complex located at the end of the chromosomes. They shorten with every cell division and, thus are markers for cellular aging, senescence, and replicative capacity. Telomere dysfunction is linked to several bone marrow disorders, including dyskeratosis congenita, aplastic anemia, myelodysplastic syndrome, and hematopoietic malignancies. Hematopoietic stem cell transplantation (HSCT) provides an opportunity in which to study telomere dynamics in a high cell proliferative environment. Rapid telomere shortening of donor cells occurs in the recipient shortly after HSCT; the degree of telomere attrition does not appear to differ by graft source. As expected, telomeres are longer in recipients of grafts with longer telomeres (e.g., cord blood). Telomere attrition may play a role in, or be a marker of, long term outcome after HSCT, but these data are limited. In this review, we discuss telomere biology in normal and abnormal hematopoiesis, including HSCT.
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Affiliation(s)
- Shahinaz M Gadalla
- Clinical Genetics Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, Bethesda, MD 20852, USA.
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Sano R, Nakajima T, Takahashi K, Kubo R, Yazawa S, Kominato Y. The 3' flanking region of the human ABO histo-blood group gene is involved in negative regulation of gene expression. Leg Med (Tokyo) 2010; 13:22-9. [PMID: 21144789 DOI: 10.1016/j.legalmed.2010.10.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2010] [Accepted: 10/13/2010] [Indexed: 10/18/2022]
Abstract
Gene expression is driven by promoters, enhancers, silencers, and other cis-regulatory elements upstream and downstream of the gene. Previous studies of the regulation of human ABO gene transcription have focused mainly on the 5' region, including the core promoter and the region proximal to it. However, as the involvement of the 3' flanking region in transcriptional regulation has not yet been examined, we focused on this issue. The 3' region approximately 2.2kb downstream of the ABO gene was PCR-amplified and inserted into a cloning vector, followed by sequence determination and preparation of luciferase reporter vectors. Transient transfections into KATOIII and K562 cells were performed using various reporter plasmids containing the 3' region. The 3' region of the ABO gene, which was characterized by a high degree of sequence repetition, was effectively cloned by a single-copy cloning method. Transfections in KATOIII and K562 cells showed that negative elements were demonstrable within the 3' region. These observations suggest that negative regulatory elements seem to be present in the 3' region of ABO in both epithelial and erythroid lineages. As we had observed a negative region just upstream of the ABO promoter, transcription from ABO could be negatively regulated by repressive regions just upstream of the promoter and downstream of the gene. Further studies of the enhancer will be required for elucidating the molecular basis of ABO gene expression.
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Affiliation(s)
- Rie Sano
- Department of Legal Medicine, Gunma University, Graduate School of Medicine, Gunma, Japan
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Keller G, Brassat U, Braig M, Heim D, Wege H, Brümmendorf TH. Telomeres and telomerase in chronic myeloid leukaemia: impact for pathogenesis, disease progression and targeted therapy. Hematol Oncol 2009; 27:123-9. [PMID: 19569255 DOI: 10.1002/hon.901] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Telomeres are specialized structures localized at the end of human chromosomes. Due to the end replication problem, each cell division results in a loss of telomeric repeats in normal somatic cells. In germ line and stem cells, the multicomponent enzyme telomerase maintains the length of telomere repeats. However, elevated telomerase activity has also been reported in the majority of solid tumours as well as in acute and chronic leukaemia. Chronic myeloid leukaemia (CML) serves as a model disease to study telomere biology in clonal myeloproliferative disorders. In CML, telomere shortening correlates with disease stage, duration of chronic phase (CP), prognosis measured by the Hasford risk score and the response to disease-modifying therapeutics such as the tyrosine kinase inhibitor Imatinib. In addition, telomerase activity (TA) is already increased in CP CML and further upregulated with disease progression to accelerated phase and blast crisis (BC). Furthermore, a correlation of TA with increased genetic instability as well as a shorter survival of the patients has been reported. Here, we review the current state of knowledge of the role of telomere and telomerase biology in CML and discuss the possible impact of novel treatment approaches.
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Affiliation(s)
- Gunhild Keller
- Klinik für Onkologie und Hämatologie mit der Sektion Pneumologie, Universitäres Cancer Center Hamburg (UCCH), Universitätsklinikum Hamburg-Eppendorf, 20246 Hamburg, Germany
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Recent insights into the molecular mechanisms involved in aging and the malignant transformation of adult stem/progenitor cells and their therapeutic implications. Ageing Res Rev 2009; 8:94-112. [PMID: 19114129 DOI: 10.1016/j.arr.2008.12.001] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2008] [Accepted: 12/04/2008] [Indexed: 02/07/2023]
Abstract
Recent advancements in tissue-resident adult stem/progenitor cell research have revealed that enhanced telomere attrition, oxidative stress, ultraviolet radiation exposure and oncogenic events leading to severe DNA damages and genomic instability may occur in these immature and regenerative cells during chronological aging. Particularly, the alterations in key signaling components controlling their self-renewal capacity and an up-regulation of tumor suppressor gene products such as p16(INK4A), p19(ARF), ataxia-telangiectasia mutated (ATM) kinase, p53 and/or the forkhead box O (FOXOs) family of transcription factors may result in their dysfunctions, growth arrest and senescence or apoptotic death during the aging process. These molecular events may culminate in a progressive decline in the regenerative functions and the number of tissue-resident adult stem/progenitor cells, and age-related disease development. Conversely, the telomerase re-activation and accumulation of numerous genetic and/or epigenetic alterations in adult stem/progenitor cells with advancing age may result in their immortalization and malignant transformation into highly leukemic or tumorigenic cancer-initiating cells and cancer initiation. Therefore, the cell-replacement and gene therapies and molecular targeting of aged and dysfunctional adult stem/progenitor cells including their malignant counterpart, cancer-initiating cells, hold great promise for treating and even curing diverse devastating human diseases. These diseases include premature aging diseases, hematopoietic, cardiovascular, musculoskeletal, pulmonary, ocular, urogenital, neurodegenerative and skin disorders and aggressive and recurrent cancers.
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Hartmann U, Balabanov S, Ziegler P, Fellenberg J, van der Kuip H, Duyster J, Lipp HP, Bokemeyer C, Kanz L, Brümmendorf TH. Telomere length and telomerase activity in the BCR-ABL-transformed murine Pro-B cell line BaF3 is unaffected by treatment with imatinib. Exp Hematol 2005; 33:542-9. [PMID: 15850831 DOI: 10.1016/j.exphem.2005.02.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2004] [Revised: 12/27/2004] [Accepted: 02/01/2005] [Indexed: 11/28/2022]
Abstract
OBJECTIVE Imatinib mesylate is a novel tyrosine kinase inhibitor used for the treatment of Philadelphia chromosome positive (Ph+) leukemia and other malignancies. In previous studies, we found significant telomere shortening in Ph+ cells from patients with chronic myeloid leukemia (CML). Interestingly, imatinib treatment was found to lead to a normalization of previously shortened telomere length in CML patients. Based on recent reports demonstrating that c-ABL phosphorylates hTERT and thereby inhibits hTERT activity, a direct effect of imatinib on hTERT activity leading to telomere elongation in BCR-ABL-positive cells has been proposed by others. Such an effect could be of potential importance for telomere maintenance in Ph+ cells by facilitating clonal selection and progression of the disease to blast crisis. METHODS We investigated the impact of imatinib on telomere length and telomerase activity of the interleukin-3 (IL-3)-dependent murine pro-B cell line BaF3 and the BCR-ABL-positive, IL-3-independent transfectant BaF3p185 in vitro. RESULTS When BaF3 and BaF3p185 cells were treated with imatinib (the latter being rescued with IL-3), no effect on either telomerase activity or telomere length was observed. These findings can be explained by the cytoplasmatic localization of BCR-ABL found in BaF3p185 as compared to the nuclear localization of telomerase (and c-ABL). CONCLUSION As opposed to recent reports for c-ABL, we do not see evidence for a functional interaction between BCR-ABL and hTERT in this model system arguing against imatinib-mediated upregulation of hTERT as a crucial factor for clonal selection and disease progression of CML.
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Affiliation(s)
- Ulrike Hartmann
- Department of Hematology and Oncology, University of Tübingen, Tübingen, Germany
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von Bubnoff N, Peschel C, Duyster J. Resistance of Philadelphia-chromosome positive leukemia towards the kinase inhibitor imatinib (STI571, Glivec): a targeted oncoprotein strikes back. Leukemia 2003; 17:829-38. [PMID: 12750693 DOI: 10.1038/sj.leu.2402889] [Citation(s) in RCA: 86] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Cancer research within the last decades elucidated signaling pathways and identified genes and proteins that lead or contribute to malignant transformation of a cell. Discovery of the Bcr-Abl oncoprotein as the molecular abnormality causing chronic myeloid leukemia (CML) paved the way for the development of a targeted anticancer therapy. The substantial activity of imatinib mesylate (STI571, Glivec) in CML and Philadelphia (Ph)-chromosome positive acute lymphoblastic leukemia (Ph+ ALL) changed the therapeutic approach to Ph+ leukemia and rang the bell for a new era of anticancer treatment. However, when the phenomenon of relapse occurred despite continued imatinib treatment, we had to learn the lesson that imatinib can select for a resistant disease clone. If such a clone still depends on Bcr-Abl, it either carries a BCR-ABL point mutation that prevents binding of the drug or expresses the fusion protein at high levels. Alternatively, leukemia cells that harbor secondary genetic alterations resulting in Bcr-Abl-independent proliferation are selected for their growth advantage in the presence of imatinib. Point mutations in the BCR-ABL kinase domain prevent binding of imatinib but still allow binding of ATP, thus retaining Bcr-Abl kinase activity. Mutated BCR-ABL is frequently detected in cases of imatinib-resistant Ph+ leukemia and therefore represents the main challenge for the investigation of alternative strategies to either overcome resistance or to prevent the emergence of a resistant leukemic clone.
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Affiliation(s)
- N von Bubnoff
- 1Laboratory of Leukemogenesis, Department of Internal Medicine III, Technical University of Munich, Germany
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Verstovsek S, Kantarjian H, Manshouri T, Cortes J, Faderl S, Giles FJ, Keating M, Albitar M. Increased telomerase activity is associated with shorter survival in patients with chronic phase chronic myeloid leukemia. Cancer 2003; 97:1248-52. [PMID: 12599232 DOI: 10.1002/cncr.11217] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
BACKGROUND Significantly elevated telomerase activity (TA) has been found in samples from patients with many malignant hematologic diseases. However, the impact of elevated TA on the course of patients with chronic phase chronic myeloid leukemia (CP-CML) is unknown. METHODS Using a modified polymerase chain reaction-based telomeric repeat amplification protocol assay, the authors measured TA in bone marrow samples from 93 patients with CP-CML and correlated it with patient characteristics and survival. TA also was measured in bone marrow samples from 29 patients with accelerated/blastic phase CML. RESULTS Patients with accelerated/blastic phase CML were found to have somewhat higher levels of TA compared with patients with CP-CML (P = 0.07). Among patients with CP-CML, those with high TA progressed to advanced stages of disease sooner (P = 0.05) and had a significantly shorter survival (P = 0.04) than patients with low TA. No correlation was found between TA and patient age, hemoglobin, platelet and leukocyte counts, percentage of peripheral or bone marrow blasts or basophils, or bone marrow cellularity. On multivariate analysis, high TA retained its significance as a factor associated with shorter patient survival (P = 0.02). CONCLUSIONS The current study data suggest that TA plays a role in the propagation of CP-CML and that the potential of telomerase inhibitors in patients with CML should be explored, even in those with early phase disease.
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Affiliation(s)
- Srdan Verstovsek
- Department of Leukemia, University of Texas M. D. Anderson Cancer Center, Houston, Texas 77030, USA
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Feller SM, Tuchscherer G, Voss J. High affinity molecules disrupting GRB2 protein complexes as a therapeutic strategy for chronic myelogenous leukaemia. Leuk Lymphoma 2003; 44:411-27. [PMID: 12688310 DOI: 10.1080/1042819021000037930] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Chronic myelogenous leukaemia (CML) is one of the most intensively studied human malignancies. It has been the focus of major efforts to develop potent drugs for several decades, but until recently cure rates remained low. A breakthrough in CML therapy was very likely accomplished with the clinical introduction of STI-571 [imatinib mesylate; Gleevec (USA); Glivec (other countries)] in 2000/2001. Despite the hope that STI-571 has generated for many CML patients, development of resistance to this drug is already apparent in some cases, especially if the CML is diagnosed in its later stages. Therefore, novel drugs which can be used alone or in combination with STI-571 are highly desirable. This review briefly summarises the current understanding and therapy of CML and then discusses in more detail basic laboratory research that attempts to target Grb2, an adaptor protein known to directly interact with the Bcr portion of the Bcr-Abl fusion protein. Blocking the binding of Grb2 to the GDP-releasing protein SoS is well known to abrogate the activation of the GTPase Ras, a major driving force of the central mitogenic (MAP kinase) pathway. Additional Grb2 effector proteins may also contribute to the proliferation-inhibiting effects observed upon uncoupling Grb2 from its downstream signalling system. Since Grb2 is a known signal transducer for several major human oncogenes, this approach may have applications for a wider range of human cancers.
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MESH Headings
- Adaptor Proteins, Signal Transducing
- Animals
- Antineoplastic Agents/chemistry
- Antineoplastic Agents/pharmacology
- Antineoplastic Combined Chemotherapy Protocols/therapeutic use
- Benzamides
- Drug Design
- Enzyme Inhibitors/administration & dosage
- Enzyme Inhibitors/therapeutic use
- Fatty Acids, Unsaturated/pharmacology
- Forecasting
- Fusion Proteins, bcr-abl/antagonists & inhibitors
- Fusion Proteins, bcr-abl/metabolism
- GRB2 Adaptor Protein
- Humans
- Imatinib Mesylate
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/drug therapy
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/metabolism
- Macromolecular Substances
- Mice
- Neoplasm Proteins/antagonists & inhibitors
- Neoplasm Proteins/metabolism
- Peptide Fragments/metabolism
- Phosphatidylinositol 3-Kinases/physiology
- Piperazines/administration & dosage
- Piperazines/therapeutic use
- Protein Binding/drug effects
- Proteins/antagonists & inhibitors
- Proteins/chemistry
- Proteins/metabolism
- Pyrimidines/administration & dosage
- Pyrimidines/therapeutic use
- Signal Transduction/drug effects
- Son of Sevenless Proteins/physiology
- Structure-Activity Relationship
- Transcription Factors/physiology
- ras Proteins/antagonists & inhibitors
- src Homology Domains
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Affiliation(s)
- Stephan M Feller
- Cell Signalling Group, Molecular Oncology Laboratory, Cancer Research UK, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, UK. stephan.feller@.cancer.org.uk
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Smith DL, Evans CA, Pierce A, Gaskell SJ, Whetton AD. Changes in the proteome associated with the action of Bcr-Abl tyrosine kinase are not related to transcriptional regulation. Mol Cell Proteomics 2002; 1:876-84. [PMID: 12488463 DOI: 10.1074/mcp.m200035-mcp200] [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: 11/06/2022] Open
Abstract
Chronic myeloid leukemia (CML) is a hematopoietic stem cell disease, the hallmark of which is the Bcr-Abl protein tyrosine kinase (PTK). Without intervention the disease progresses from a benign chronic phase to a rapidly fatal blast crisis. To identify the molecular mechanisms underlying disease progression we used two-dimensional gel electrophoresis on a model we have previously described using the expression of a conditional mutant of Bcr-Abl PTK in a multipotent stem cell line, FDCP-Mix. Long term exposure of FDCP-Mix cells to Bcr-Abl mimics disease progression in CML. Four major differences were observed as a consequence of long term exposure to the Bcr-Abl PTK compared with cells exposed short term. The proteins were identified using matrix-assisted laser desorption ionization-time of flight mass spectrometry-generated peptide mass fingerprint data and liquid chromatography-tandem mass spectrometry-generated sequence information. Leukotriene A4 hydrolase, an enzyme known to be deregulated in CML, was found to be up-regulated. Annexin VI, vacuolar ATP synthase catalytic subunit A, and mortalin were found to be down-regulated. Poly(A) PCR cDNA analysis showed there was no correlation between the protein expression changes and mRNA levels. Western blot analysis also indicated no change in the levels of mortalin or leukotriene A4 hydrolase, indicating that post-translational events may modify protein content of the specific spots. Leukotriene B4 levels (product of leukotriene A4 hydrolase) were, however, reduced in cells exposed long term to Bcr-Abl activity. This study demonstrates the potential of proteomic analysis to define novel effects of oncogenes.
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Affiliation(s)
- Duncan L Smith
- Leukaemia Research Fund Cellular Development Unit, Department of Biomolecular Sciences, University of Manchester Institute of Science and Technology, Manchester, United Kingdom
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Blagosklonny MV. STI-571 must select for drug-resistant cells but 'no cell breathes fire out of its nostrils like a dragon'. Leukemia 2002; 16:570-2. [PMID: 11960334 DOI: 10.1038/sj.leu.2402409] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2001] [Accepted: 11/30/2001] [Indexed: 11/09/2022]
Abstract
Seemingly disappointing, the Bcr-Abl kinase inhibitor STI-571 shares an 'unfortunate' characteristic with conventional cancer drugs: the development of drug resistance. I argue that the resistance must develop even faster to STI-571 than to conventional drugs, because STI-571 is so effective. This is predictable, but is it inevitable? And how do mechanisms of resistance in relapse depend on a degree of remission. In addition to mutation rate and number of tumor cells, one additional factor determines relapse vs. 'extinction' of the leukemia cell population.
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MESH Headings
- Benzamides
- Drug Resistance, Neoplasm
- Enzyme Inhibitors/pharmacology
- Fusion Proteins, bcr-abl
- Humans
- Imatinib Mesylate
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/drug therapy
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/genetics
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/pathology
- Piperazines/pharmacology
- Protein-Tyrosine Kinases/antagonists & inhibitors
- Pyrimidines/pharmacology
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Affiliation(s)
- M V Blagosklonny
- Medicine Branch, National Cancer Institute, NIH, Bethesda, MD 20892, USA
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