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Myelodysplastic Syndromes in the Postgenomic Era and Future Perspectives for Precision Medicine. Cancers (Basel) 2021; 13:cancers13133296. [PMID: 34209457 PMCID: PMC8267785 DOI: 10.3390/cancers13133296] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Revised: 06/18/2021] [Accepted: 06/21/2021] [Indexed: 12/19/2022] Open
Abstract
Simple Summary With demographic ageing, improved cancer survivorship and increased diagnostic sensitivity, incident cases of patients with Myelodysplastic Syndromes (MDS) are continuously rising, leading to a relevant impact on health care resources. Disease heterogeneity and various comorbidities are challenges for the management of the generally elderly patients. Therefore, experienced physicians and multidisciplinary teams should be involved in the establishment of the correct diagnosis, risk-assessment and personalized treatment plan. Next-generation sequencing allows for early detection of clonal hematopoiesis and monitoring of clonal evolution, but also poses new challenges for its appropriate use. At present, allogeneic hematopoietic stem cell transplantation remains the only curative treatment option for a minority of fit MDS patients. All others receive palliative treatment and will eventually progress, having an unmet need for novel therapies. Targeting compounds are in prospect for precision medicine, however, abrogation of clonal evolution to acute myeloid leukemia remains actually out of reach. Abstract Myelodysplastic syndromes (MDS) represent a heterogeneous group of clonal disorders caused by sequential accumulation of somatic driver mutations in hematopoietic stem and progenitor cells (HSPCs). MDS is characterized by ineffective hematopoiesis with cytopenia, dysplasia, inflammation, and a variable risk of transformation into secondary acute myeloid leukemia. The advent of next-generation sequencing has revolutionized our understanding of the genetic basis of the disease. Nevertheless, the biology of clonal evolution remains poorly understood, and the stochastic genetic drift with sequential accumulation of genetic hits in HSPCs is individual, highly dynamic and hardly predictable. These continuously moving genetic targets pose substantial challenges for the implementation of precision medicine, which aims to maximize efficacy with minimal toxicity of treatments. In the current postgenomic era, allogeneic hematopoietic stem cell transplantation remains the only curative option for younger and fit MDS patients. For all unfit patients, regeneration of HSPCs stays out of reach and all available therapies remain palliative, which will eventually lead to refractoriness and progression. In this review, we summarize the recent advances in our understanding of MDS pathophysiology and its impact on diagnosis, risk-assessment and disease monitoring. Moreover, we present ongoing clinical trials with targeting compounds and highlight future perspectives for precision medicine.
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Shahjahani M, Abroun A, Saki N, Bagher Mohammadi SM, Rezaeeyan H. STAT5: From Pathogenesis Mechanism to Therapeutic Approach in Acute Leukemia. Lab Med 2021; 51:345-351. [PMID: 31860086 DOI: 10.1093/labmed/lmz074] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND Based on the results of multiple studies, multiple signaling pathways is a major cause of resistence to chemotherapy in leukemia cells. Signal transducer and activator of transcription 5 (STAT5) is among these factors; it plays an essential role in proliferation of leukemic cells. METHODS We obtained the materials used in our study via PubMed search from 1996 through 2019. The key search terms included "STAT5," "acute leukemia," "leukemogenesis," and "mutation." RESULTS On activation, STAT5 not only inhibits apoptosis of leukemic cells via activating the B-cell lymphoma 2 (BCL-2) gene but also inhibits resistance to chemotherapy by enhancing human telomerase reverse transcriptase (hTERT) expression and maintaining telomere length in cells. It has also been shown that a number of mutations in the STAT5 gene and in related genes alter the expression of STAT5. CONCLUSION The identification of STAT5 and the factors activated in its up- or downstream expression, affecting its function, contribute to better treatments such as targeted therapy rather than chemotherapy, improving the quality of life patients.
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Affiliation(s)
- Mohammad Shahjahani
- Thalassemia and Hemoglobinopathy Research Center, Research Institute of Health, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
| | - Amirreza Abroun
- Royan Stem Cell Technology Company, Royan Institute Tehran, Iran
| | - Najmaldin Saki
- Thalassemia and Hemoglobinopathy Research Center, Research Institute of Health, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
| | | | - Hadi Rezaeeyan
- Thalassemia and Hemoglobinopathy Research Center, Research Institute of Health, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
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Steensma DP, Fenaux P, Van Eygen K, Raza A, Santini V, Germing U, Font P, Diez-Campelo M, Thepot S, Vellenga E, Patnaik MM, Jang JH, Varsos H, Bussolari J, Rose E, Sherman L, Sun L, Wan Y, Dougherty S, Huang F, Feller F, Rizo A, Platzbecker U. Imetelstat Achieves Meaningful and Durable Transfusion Independence in High Transfusion-Burden Patients With Lower-Risk Myelodysplastic Syndromes in a Phase II Study. J Clin Oncol 2020; 39:48-56. [PMID: 33108243 DOI: 10.1200/jco.20.01895] [Citation(s) in RCA: 70] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
PURPOSE Patients with lower-risk (LR) myelodysplastic syndromes (MDS) who are RBC transfusion dependent and have experienced relapse after or are refractory to erythropoiesis-stimulating agent (ESA) have limited treatment options. High telomerase activity and human telomerase reverse-transcription expression in clonal hematopoietic cells have been reported in patients with MDS. Imetelstat, a first-in-class competitive inhibitor of telomerase enzymatic activity, targets cells with active telomerase. We report efficacy, safety, and biomarker data for patients with LR MDS who are RBC transfusion dependent and who were relapsed/refractory to ESAs. PATIENTS AND METHODS In this two-part phase II/III study (MDS3001), the primary end point was 8-week RBC transfusion independence (TI) rate, with key secondary end points of 24-week RBC TI rate, TI duration, and hematologic improvement-erythroid. RESULTS Data from the phase II part of the study are reported. Of 57 patients enrolled and treated (overall population), 38 were non-del(5q) and hypomethylating agent and lenalidomide naïve (subset population). The 8- and 24-week RBC TI rates in the overall population were 37% and 23%, respectively, with a median TI duration of 65 weeks. In the subset population, 8- and 24-week RBC TI rates were 42% and 29%, respectively, with a median TI duration of 86 weeks. Eight-week TI rate was observed across all subgroups evaluated. Cytogenetic and mutational data revealed a reduction of the malignant clones, suggesting disease modification activity. The most common adverse events were cytopenias, typically reversible within 4 weeks. CONCLUSION Imetelstat treatment results in a meaningful, durable TI rate across a broad range of heavily transfused patients with LR MDS who are ineligible for or relapsed/refractory to ESAs. Biomarker analyses indicated effects on the mutant malignant clone.
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Affiliation(s)
| | - Pierre Fenaux
- Hôpital Saint-Louis, Université Paris Diderot, Paris, France
| | | | - Azra Raza
- Columbia University Medical Center, New York, NY
| | - Valeria Santini
- MDS Unit, AOU Careggi-University of Florence, Florence, Italy
| | - Ulrich Germing
- Klinik für Hämatologie, Onkologie and Klinische lmmunologie, Universitätsklinik Düsseldorf, Heinrich-Heine-Universität, Düsseldorf, Germany
| | - Patricia Font
- Department of Hematology, Hospital General Universitario Gregorio Marañon, Madrid, Spain
| | - Maria Diez-Campelo
- Hematology Department, The University Hospital of Salamanca, Salamanca, Spain
| | | | - Edo Vellenga
- Department of Hematology, University Medical Center Groningen, University of Groningen, Groningen, the Netherlands
| | - Mrinal M Patnaik
- Division of Hematology, Department of Internal Medicine, Mayo Clinic, Rochester, MN
| | - Jun Ho Jang
- Department of Hematology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea
| | | | | | | | | | - Libo Sun
- Geron Corporation, Menlo Park, CA
| | - Ying Wan
- Geron Corporation, Menlo Park, CA
| | | | | | | | | | - Uwe Platzbecker
- Department of Hematology and Cell Therapy, University Clinic Leipzig, Leipzig, Germany
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Imetelstat inhibits growth of megakaryocyte colony-forming units from patients with essential thrombocythemia. Blood Adv 2020; 3:3724-3728. [PMID: 31770436 DOI: 10.1182/bloodadvances.2019000167] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2019] [Accepted: 10/21/2019] [Indexed: 11/20/2022] Open
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Safa M, Jafari L, Alikarami F, Manafi Shabestari R, Kazemi A. Indole-3-carbinol induces apoptosis of chronic myelogenous leukemia cells through suppression of STAT5 and Akt signaling pathways. Tumour Biol 2017. [PMID: 28631564 DOI: 10.1177/1010428317705768] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Signal transducer and activator of transcription 5 and Akt pathways, implicated in signaling transduction downstream of BCR-ABL, play critical roles in the pathogenesis of chronic myeloid leukemia. Therefore, idenication of novel compounds that modulate the activity of such pathways could be a new approach in the treatment of chronic myeloid leukemia. Previous studies have demonstrated that indole-3-carbinol inhibits the proliferation and induces apoptosis of various tumor cells. However, its anticancer activity against chronic myeloid leukemia cells and the underlying mechanism remain unclear. Our data revealed that indole-3-carbinol promoted mitochondrial apoptosis of chronic myeloid leukemia-derived K562 cells, as evidenced by the activation of caspases and poly (ADP-ribose) polymerase cleavage. Treatment with indole-3-carbinol was found to be associated with a decrease in the cellular levels of phospho-Akt and phospho-signal transducer and activator of transcription 5. In addition, real-time polymerase chain reaction analysis showed that the downregulation of genes is regulated by Akt and signal transducer and activator of transcription 5. We also found that treatment with indole-3-carbinol resulted in the activation of the p38 mitogen-activated protein kinase and reduced expression of human telomerase and c-Myc. Collectively, these results demonstrate that the oncogenic signal transducer and activator of transcription 5/Akt pathway is a cellular target for indole-3-carbinol in chronic myeloid leukemia cells. Thus, this clinically tested natural compound can be a potential candidate in the treatment of chronic myeloid leukemia following confirmation with clinical studies.
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Affiliation(s)
- Majid Safa
- 1 Cellular and Molecular Research Center, Iran University of Medical Sciences, Tehran, Iran.,2 Department of Hematology, Faculty of Allied Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Leila Jafari
- 2 Department of Hematology, Faculty of Allied Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Fatemeh Alikarami
- 2 Department of Hematology, Faculty of Allied Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Rima Manafi Shabestari
- 2 Department of Hematology, Faculty of Allied Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Ahmad Kazemi
- 2 Department of Hematology, Faculty of Allied Medicine, Iran University of Medical Sciences, Tehran, Iran
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Emerging treatments for classical myeloproliferative neoplasms. Blood 2016; 129:693-703. [PMID: 28028027 DOI: 10.1182/blood-2016-10-695965] [Citation(s) in RCA: 71] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2016] [Accepted: 12/03/2016] [Indexed: 12/17/2022] Open
Abstract
There has been a major revolution in the management of patients with myeloproliferative neoplasms (MPN), and in particular those with myelofibrosis and extensive splenomegaly and symptomatic burden, after the introduction of the JAK1 and JAK2 inhibitor ruxolitinib. The drug also has been approved as second-line therapy for polycythemia vera (PV). However, the therapeutic armamentarium for MPN is still largely inadequate for coping with patients' major unmet needs, which include normalization of life span (myelofibrosis and some patients with PV), reduction of cardiovascular complications (mainly PV and essential thrombocythemia), prevention of hematological progression, and improved quality of life (all MPN). In fact, none of the available drugs has shown clear evidence of disease-modifying activity, even if some patients treated with interferon and ruxolitinib showed reduction of mutated allele burden, and ruxolitinib might extend survival of patients with higher-risk myelofibrosis. Raised awareness of the molecular abnormalities and cellular pathways involved in the pathogenesis of MPN is facilitating the development of clinical trials with novel target drugs, either alone or in combination with ruxolitinib. Although for most of these molecules a convincing preclinical rationale was provided, the results of early phase 1 and 2 clinical trials have been quite disappointing to date, and toxicities sometimes have been limiting. In this review, we critically illustrate the current landscape of novel therapies that are under evaluation for patients with MPN on the basis of current guidelines, patient risk stratification criteria, and previous experience, looking ahead to the chance of a cure for these disorders.
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Dahlström J, Zhang X, Ghaderi M, Hultcrantz M, Björkholm M, Xu D. Dysregulation of shelterin factors coupled with telomere shortening in Philadelphia chromosome negative myeloproliferative neoplasms. Haematologica 2015; 100:e402-5. [PMID: 26185173 DOI: 10.3324/haematol.2015.125765] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Affiliation(s)
- Jenny Dahlström
- Department of Medicine, Division of Hematology and Center for Molecular Medicine, Karolinska University Hospital Solna and Karolinska Institutet, Stockholm, Sweden
| | - Xiaolu Zhang
- Department of Medicine, Division of Hematology and Center for Molecular Medicine, Karolinska University Hospital Solna and Karolinska Institutet, Stockholm, Sweden
| | - Mehran Ghaderi
- Department of Pathology, Karolinska University Hospital Solna and Karolinska Institutet, Stockholm, Sweden
| | - Malin Hultcrantz
- Department of Medicine, Division of Hematology and Center for Molecular Medicine, Karolinska University Hospital Solna and Karolinska Institutet, Stockholm, Sweden
| | - Magnus Björkholm
- Department of Medicine, Division of Hematology and Center for Molecular Medicine, Karolinska University Hospital Solna and Karolinska Institutet, Stockholm, Sweden
| | - Dawei Xu
- Department of Medicine, Division of Hematology and Center for Molecular Medicine, Karolinska University Hospital Solna and Karolinska Institutet, Stockholm, Sweden
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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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Kim M, Oh B, Kim TY, Yoon SS, Kim SY, Hwang SM, Lee DS. Elevated telomerase activity in essential thrombocythemia with extreme thrombocytosis. Clin Biochem 2014; 47:389-92. [PMID: 24440836 DOI: 10.1016/j.clinbiochem.2014.01.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2013] [Revised: 12/12/2013] [Accepted: 01/09/2014] [Indexed: 12/22/2022]
Abstract
INTRODUCTION We performed a comparative analysis of telomerase activity (TA) in patients with myeloproliferative neoplasm (MPN) and myelodysplastic syndrome (MDS). The relationships between TA and known prognostic factors were also analyzed. MATERIALS AND METHODS A telomeric repeat amplification protocol was performed with bone marrow hematopoietic cells from 96 normal controls, 44 MPNs, and 40 MDSs. RESULT TA (measured as molecules/reaction) showed no correlation with age in the control group (R(2)=0.0057, p=0.464). MPN showed elevated TA compared with controls (15,537.57 vs. 7775.44, p=0.020). Patients with essential thrombocythemia showed markedly elevated TA (22,688.56, p=0.030), particularly in cases with extreme thrombocytosis versus those without extreme thrombocytosis (34,522.19 vs. 9375.71, p=0.041). MDS patients showed a TA value of 7578.50. CONCLUSION There was no association between age and TA in bone marrow hematopoietic cells. TA was elevated in MPN but borderline in MDS, probably because of differences in the nature of the diseases. Elevated TA in patients with essential thrombocythemia, especially those with extreme thrombocytosis, suggests that an anti-telomerase strategy could be beneficial in the prevention of thrombotic complications.
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Affiliation(s)
- Miyoung Kim
- Department of Laboratory Medicine, Hallym University Sacred Heart Hospital, Anyang, China
| | - Bora Oh
- Department of Oncology, Asan Medical Center, Seoul, Republic of Korea
| | - Tae Young Kim
- Department of Tumor Biology, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Sung-Soo Yoon
- Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Seon Young Kim
- Department of Laboratory Medicine, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Sang Mee Hwang
- Department of Laboratory Medicine, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Dong Soon Lee
- Department of Tumor Biology, Seoul National University College of Medicine, Seoul, Republic of Korea; Department of Laboratory Medicine, Seoul National University College of Medicine, Seoul, Republic of Korea; Cancer Research Institute, Seoul National University College of Medicine, Seoul, Republic of Korea.
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Myelofibrosis in Philadelphia chromosome-negative myeloproliferative neoplasms is associated with aberrant karyotypes. Cancer Genet 2013; 206:116-23. [PMID: 23571153 DOI: 10.1016/j.cancergen.2013.02.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2012] [Revised: 02/25/2013] [Accepted: 02/25/2013] [Indexed: 12/15/2022]
Abstract
In Philadelphia chromosome-negative myeloproliferative neoplasms (Ph¯ MPN), non-specific chromosomal defects are detectable and essential thrombocythemia (ET) has the lowest rate of aberrations, whereas primary myelofibrosis (PMF) and post-polycythemia vera (PV) myelofibrosis have the highest rates of aberrations. The frequency of cytogenetic defects in pre-fibrotic stage PMF has not been characterized thus far and the underlying molecular defects of chromosomal instability are unknown. In this study, histopathological findings were correlated with cytogenetic data (n = 249). The expression of DNA repair factors ERCC1 and LIG4 were determined in Ph¯ MPN with and without cytogenetic aberrations. Pre-fibrotic PMF and ET have similarly low frequencies of karyotype anomalies. The expression of ERCC1, but not LIG4, is increased in fibrotic stage PMF but is not associated with accumulation of cytogenetic defects. In conclusion, aberrant karyotypes in Ph¯ MPN reflect the chromosomal instability in these diseases and, in comparison with pre-fibrotic stages, Ph¯ MPN with fibrosis has the highest frequency of cytogenetic aberrations.
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Chai JH, Zhang Y, Tan WH, Chng WJ, Li B, Wang X. Regulation of hTERT by BCR-ABL at multiple levels in K562 cells. BMC Cancer 2011; 11:512. [PMID: 22151181 PMCID: PMC3259104 DOI: 10.1186/1471-2407-11-512] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2011] [Accepted: 12/09/2011] [Indexed: 03/05/2023] Open
Abstract
BACKGROUND The cytogenetic characteristic of Chronic Myeloid Leukemia (CML) is the formation of the Philadelphia chromosome gene product, BCR-ABL. Given that BCR-ABL is the specific target of Gleevec in CML treatment, we investigated the regulation of the catalytic component of telomerase, hTERT, by BCR-ABL at multiple levels in K562 cells. METHODS Molecular techniques such as over expression, knockdown, real-time PCR, immunoprecipitation, western blotting, reporter assay, confocal microscopy, telomerase assays and microarray were used to suggest that hTERT expression and activity is modulated by BCR-ABL at multiple levels. RESULTS Our results suggest that BCR-ABL plays an important role in regulating hTERT in K562 (BCR-ABL positive human leukemia) cells. When Gleevec inhibited the tyrosine kinase activity of BCR-ABL, phosphorylation of hTERT was downregulated, therefore suggesting a positive correlation between BCR-ABL and hTERT. Gleevec treatment inhibited hTERT at mRNA level and significantly reduced telomerase activity (TA) in K562 cells, but not in HL60 or Jurkat cells (BCR-ABL negative cells). We also demonstrated that the transcription factor STAT5a plays a critical role in hTERT gene regulation in K562 cells. Knockdown of STAT5a, but not STAT5b, resulted in a marked downregulation of hTERT mRNA level, TA and hTERT protein level in K562 cells. Furthermore, translocation of hTERT from nucleoli to nucleoplasm was observed in K562 cells induced by Gleevec. CONCLUSIONS Our data reveal that BCR-ABL can regulate TA at multiple levels, including transcription, post-translational level, and proper localization. Thus, suppression of cell growth and induction of apoptosis by Gleevec treatment may be partially due to TA inhibition. Additionally, we have identified STAT5a as critical mediator of the hTERT gene expression in BCR-ABL positive CML cells, suggesting that targeting STAT5a may be a promising therapeutic strategy for BCR-ABL positive CML patients.
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Affiliation(s)
- Juin Hsien Chai
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, 8 Medical Drive, 117597 Singapore, Singapore
| | - Yong Zhang
- Department of Biochemistry, Yong Loo Lin School of Medicine, Cancer Science Institute of Singapore (CSI), National University of Singapore, Singapore, Singapore
| | - Wei Han Tan
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, 8 Medical Drive, 117597 Singapore, Singapore
| | - Wee Joo Chng
- Department of Biochemistry, Yong Loo Lin School of Medicine, Cancer Science Institute of Singapore (CSI), National University of Singapore, Singapore, Singapore
- Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
- Department of Haematology-Oncology, National University Cancer Institute of Singapore, National University Health System, Singapore, Singapore
| | - Baojie Li
- Bio-X Center, Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders, Ministry of Education, Shanghai Jiao Tong University, Shanghai, People's Republic of China
| | - Xueying Wang
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, 8 Medical Drive, 117597 Singapore, Singapore
- Department of Biochemistry, Yong Loo Lin School of Medicine, Cancer Science Institute of Singapore (CSI), National University of Singapore, Singapore, Singapore
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Pepper C, Baird DM. Shortened telomeres: a driving force behind leukemia? Future Oncol 2011; 6:1681-6. [PMID: 21142655 DOI: 10.2217/fon.10.135] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
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Xie M, Niu JH, Chang Y, Qian QJ, Wu HP, Li LF, Zhang Y, Li JL, Huang XJ, Ruan GR. A novel triple-regulated oncolytic adenovirus carrying PDCD5 gene exerts potent antitumor efficacy on common human leukemic cell lines. Apoptosis 2009; 14:1086-94. [PMID: 19551515 DOI: 10.1007/s10495-009-0373-3] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
PDCD5 (programmed cell death 5) accelerates apoptosis of certain tumor cells and the replication-defective Ad-PDCD5 may be a promising agent for enhancing chemosensitivity. In this study, a triple-regulated conditionally replicating adenoviruses (CRAd) carrying PDCD5 gene expression cassette, SG611-PDCD5, was engineered. In SG611-PDCD5, the E1a gene with a deletion of 24 nucleotides within CR2 region is controlled under the human telomerase reverse transcriptase (hTERT) promoter, the E1b gene expression is directed by the hypoxia response element (HRE), whereas the PDCD5 gene is controlled by the cytomegalovirus promoter. The tumor-selective replication of this virus and its antitumor efficacy were characterized in several leukemic cell lines in vitro and in xenograft models of human leukemic cell line in nude mice. It was found by RQ-RT-PCR assay that SG611-PDCD5 expressed PDCD5 efficiently in leukemic cells. In K562 tumor xenograft models, SG611-PDCD5 displayed a tumor killing capacity. At a dose of 1 x 10(9) plaque-forming units, SG611-PDCD5 alone could completely inhibit the tumor growth and more effective than replication-defective Ad-PDCD5. Histopathologic examination revealed that SG611-PDCD5 administration resulted in leukemic cell apoptosis. We concluded that the triple-regulated SG611-PDCD5, as a more potent and safer antitumor therapeutic, could provide a new strategy for leukemia biotherapy.
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Affiliation(s)
- Min Xie
- Peking University People's Hospital and Institute of Hematology, Beijing, China
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Deville L, Hillion J, Ségal-Bendirdjian E. Telomerase regulation in hematological cancers: a matter of stemness? Biochim Biophys Acta Mol Basis Dis 2009; 1792:229-39. [PMID: 19419697 DOI: 10.1016/j.bbadis.2009.01.016] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2008] [Revised: 01/30/2009] [Accepted: 01/30/2009] [Indexed: 01/02/2023]
Abstract
Human telomerase is a nuclear ribonucleoprotein enzyme complex that catalyzes the synthesis and extension of telomeric DNA. This enzyme is highly expressed and active in most malignant tumors while it is usually not or transiently detectable in normal somatic cells, suggesting that it plays an important role in cellular immortalization and tumorigenesis. As most leukemic cells are generally telomerase-positive and have often shortened telomeres, our understanding of how telomerase is deregulated in these diseases could help to define novel therapies targeting the telomere/telomerase complex. Nonetheless, considering that normal hematopoietic stem cells and some of their progeny do express a functional telomerase, it is tempting to consider such an activity in leukemias as a sustained stemness feature and important to understand how telomere length and telomerase activity are regulated in the various forms of leukemias.
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Affiliation(s)
- Laure Deville
- INSERM UMR-S 685, Institut d'Hématologie, Hôpital Saint-Louis, 75475 Paris cedex 10, France
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Campbell LJ, Fidler C, Eagleton H, Peniket A, Kusec R, Gal S, Littlewood TJ, Wainscoat JS, Boultwood J. hTERT, the catalytic component of telomerase, is downregulated in the haematopoietic stem cells of patients with chronic myeloid leukaemia. Leukemia 2006; 20:671-9. [PMID: 16498395 DOI: 10.1038/sj.leu.2404141] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Telomere shortening is associated with disease progression in chronic myeloid leukaemia (CML). To investigate the biology and regulation of telomerase in CML, we evaluated expression of the telomerase components, its regulators and several telomeric-associated proteins. Quantitative real-time-polymerase chain reaction (PCR) was used to compare gene expression in the CD34+/leukaemic blast cells of 22 CML patient samples to the CD34+ cell population of healthy individuals. hTERT, the catalytic component of telomerase, was downregulated in eight of 12 chronic phase (CP) patients (P = 0.0387). Furthermore, hTERT was significantly downregulated in two of three patients in accelerated phase (AP) and seven of seven patients in blast crisis (BC), P = 0.0017. Expression of hTR and telomeric-associated proteins TEP1, TRF1, TRF2, tankyrase and PinX1 was high in the majority of CP and AP patients. With the exceptions of TEP1 and hTR, expression of these factors was highest in CP and decreased during disease progression. Expression of c-Myc, a positive regulator of hTERT transcription, correlated with hTERT expression and decreased with disease progression, falling below control levels in BC. hTERT levels were increased in CP patients following successful treatment with imatinib, relative to untreated CP patients. We suggest that reduced hTERT expression directly causes the shortened telomeres observed in CML.
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MESH Headings
- Adolescent
- Adult
- Aged
- Antigens, CD34/biosynthesis
- Benzamides
- Carrier Proteins/biosynthesis
- Cell Cycle Proteins
- DNA-Binding Proteins/biosynthesis
- DNA-Binding Proteins/genetics
- DNA-Binding Proteins/metabolism
- Disease Progression
- Down-Regulation/genetics
- Female
- Gene Expression Regulation, Enzymologic/drug effects
- Gene Expression Regulation, Enzymologic/genetics
- Gene Expression Regulation, Leukemic/drug effects
- Gene Expression Regulation, Leukemic/genetics
- Hematopoietic Stem Cells/metabolism
- Humans
- Imatinib Mesylate
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/drug therapy
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/metabolism
- Male
- Middle Aged
- Piperazines/pharmacology
- Piperazines/therapeutic use
- Proto-Oncogene Proteins c-myc/biosynthesis
- Pyrimidines/pharmacology
- Pyrimidines/therapeutic use
- RNA/biosynthesis
- RNA-Binding Proteins
- Reverse Transcriptase Polymerase Chain Reaction/methods
- Sensitivity and Specificity
- Tankyrases/biosynthesis
- Telomerase/biosynthesis
- Telomerase/genetics
- Telomerase/metabolism
- Telomeric Repeat Binding Protein 1/biosynthesis
- Telomeric Repeat Binding Protein 2/biosynthesis
- Transcription, Genetic
- Tumor Suppressor Proteins/biosynthesis
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Affiliation(s)
- L J Campbell
- Leukaemia Research Fund Molecular Haematology Unit, Nuffield Department of Clinical Laboratory Sciences, University of Oxford, John Radcliffe Hospital, Oxford, UK
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17
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Ram R, Uziel O, Lahav M. The importance of the telomere and telomerase system in hematological malignancies. Leuk Lymphoma 2006; 46:1121-35. [PMID: 16085552 DOI: 10.1080/10428190500125853] [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] [Indexed: 12/31/2022]
Abstract
Telomeres are specialized chromosomal end structures composed of repeat TTAGGG sequences in humans. They shorten with each cell division and thus serve as the "mitotic clock" of the cell. One of their main functions is the maintenance of chromosomal integrity and their excessive shortening is associated with DNA instability. Telomerase, a unique reverse transcriptase, is inactive in most somatic human cells and is up-regulated in most cancer cells. Recently, the biology of the telomere/telomerase system has attracted much attention because of its possible role in carcinogenesis and aging. In this article we review the biology of this system and its relevance to normal and malignant hematopoietic cells. The biological, diagnostic and prognostic value of telomere/telomerase biology is discussed, as well as its potential future applications in cancer therapeutics.
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Affiliation(s)
- Ron Ram
- Department of Medicine A, Rabin medical Center, Beilinson Campus, Petah-Tikva, Sackler School of Medicine, Tel-Aviv University, Tel-Aviv, Israel
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18
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Gürkan E, Tanriverdi K, Başlamişli F. Telomerase activity in myelodysplastic syndromes. Leuk Res 2005; 29:1131-9. [PMID: 16111531 DOI: 10.1016/j.leukres.2005.03.006] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2004] [Indexed: 01/14/2023]
Abstract
Myelodysplastic syndromes are clonal hematopoietic stem cell disorders characterized by ineffective hematopoiesis and peripheral cytopenias. Telomeres are thought to be critical in maintaining normal hematopoiesis. In this study, we assessed telomere dynamics in order to obtain further insight into the pathogenesis of MDS. We studied telomerase activity (TA) in mononuclear cells from peripheral blood (PB) and bone marrow (BM) from patients with myelodysplastic syndrome (MDS; n=24), acute myeloid leukemia (AML; n=14), chronic myeloid leukemia (CML; n=12) and 11 normal controls using a polymerase chain reaction-based telomeric repeat amplification assay. Telomerase activities (mean+/-S.D.) were found as 0.199+/-0.09, 0.414+/-0.55, 0.253+/-0.26 and 0.181+/-0.05 pg/ml in PB mononuclear cells, respectively (P>0.05). Comparison of TA of BM mononuclear cells from 19 MDS patients versus 10 BM samples from normal controls revealed no significant difference (P=0.3). There was no correlation between the levels of TA and clinical and prognostic parameters of the patients with MDS, such as degree of anemia, platelet counts on presentation, gender, presence of organomegaly, bone marrow fibrosis and BM blast percentages. Patients who had higher TA had significantly inferior survival compared with patients who had lower TA (P=0.005). Consistent with previous data, our results suggest that in patients with MDS, telomerase activity might be insufficient to compensate for the telomere shortening. Furthermore, TA might be prognostically important in patients with MDS. Measurements of enzymatic activity in association with telomere length studies may help to understand the prognostic role of telomere dynamics in patients with myelodysplastic syndromes more reliably.
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MESH Headings
- Adult
- Aged
- Aged, 80 and over
- Bone Marrow/enzymology
- Case-Control Studies
- Enzyme-Linked Immunosorbent Assay
- Female
- Humans
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/diagnosis
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/enzymology
- Leukemia, Myeloid, Acute/diagnosis
- Leukemia, Myeloid, Acute/enzymology
- Lymphocytes/enzymology
- Male
- Middle Aged
- Myelodysplastic Syndromes/diagnosis
- Myelodysplastic Syndromes/enzymology
- Polymerase Chain Reaction
- Survival Rate
- Telomerase/metabolism
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Affiliation(s)
- Emel Gürkan
- Department of Hematology, Cukurova University Medical School, Balcali, Adana 01330, Turkey.
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