51
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A decade of genome-wide gene expression profiling in acute myeloid leukemia: flashback and prospects. Blood 2008; 113:291-8. [PMID: 18703705 DOI: 10.1182/blood-2008-04-153239] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The past decade has shown a marked increase in the use of high-throughput assays in clinical research into human cancer, including acute myeloid leukemia (AML). In particular, genome-wide gene expression profiling (GEP) using DNA microarrays has been extensively used for improved understanding of the diagnosis, prognosis, and pathobiology of this heterogeneous disease. This review discusses the progress that has been made, places the technologic limitations in perspective, and highlights promising future avenues.
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52
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Distinct MAPK signaling pathways, p21 up-regulation and caspase-mediated p21 cleavage establishes the fate of U937 cells exposed to 3-hydrogenkwadaphnin: Differentiation versus apoptosis. Toxicol Appl Pharmacol 2008; 230:86-96. [DOI: 10.1016/j.taap.2008.02.010] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2007] [Revised: 02/13/2008] [Accepted: 02/15/2008] [Indexed: 11/20/2022]
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53
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Barbarroja N, Siendones E, Torres LA, Luque MJ, Martinez JM, Dorado G, Velasco F, Torres A, López-Pedrera C. MEK inhibition induces caspases activation, differentiation blockade and PML/RARα degradation in acute promyelocytic leukaemia. Br J Haematol 2008; 142:27-35. [DOI: 10.1111/j.1365-2141.2008.07154.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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54
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Abstract
Acute myeloid leukemia (AML) is a heterogeneous group of neoplastic disorders with great variability in clinical course and response to therapy, as well as in the genetic and molecular basis of the pathology. Major advances in the understanding of leukemogenesis have been made by the characterization and the study of acquired cytogenetic abnormalities, particularly reciprocal translocations observed in AML. Besides these major cytogenetic abnormalities, gene mutations also constitute key events in AML pathogenesis. In this review, we describe the contribution of known gene mutations to the understanding of AML pathogenesis and their clinical significance. To gain more insight in this understanding, we clustered these alterations in three groups: (1) mutations affecting genes that contribute to cell proliferation (FLT3, c-KIT, RAS, protein tyrosine standard phosphatase nonreceptor 11); (2) mutations affecting genes involved in myeloid differentiation (AML1 and CEBPA) and (3) mutations affecting genes implicated in cell cycle regulation or apoptosis (P53, NPM1). This nonexhaustive review aims to show how gene mutations interact with each other, how they contribute to refine prognosis and how they can be useful for risk-adapted therapeutic management of AML patients.
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55
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Abstract
Acute myeloid leukemia (AML) is a heterogeneous group of leukemias that result from clonal transformation of hematopoietic precursors through the acquisition of chromosomal rearrangements and multiple gene mutations. As a result of highly collaborative clinical research by pediatric cooperative cancer groups worldwide, disease-free survival has improved significantly during the past 3 decades. Further improvements in outcomes of children who have AML probably will reflect continued progress in understanding the biology of AML and the concomitant development of new molecularly targeted agents for use in combination with conventional chemotherapy drugs.
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Affiliation(s)
- Jeffrey E Rubnitz
- Department of Oncology, St Jude Children's Research Hospital, Memphis, TN 38105, USA.
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56
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Kanemura N, Tsurumi H, Okuno M, Matsushima-Nishiwaki R, Shimizu M, Moriwaki H. Retinoid X receptor alpha is highly phosphorylated in retinoic acid-resistant HL-60R cells and the combination of 9-cis retinoic acid plus MEK inhibitor induces apoptosis in the cells. Leuk Res 2007; 32:884-92. [PMID: 18082883 DOI: 10.1016/j.leukres.2007.11.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2006] [Revised: 11/03/2007] [Accepted: 11/04/2007] [Indexed: 11/30/2022]
Abstract
We examined the effects of 9-cis retinoic acid (RA) on the expression levels of retinoid X receptor alpha (RXR alpha) and its phosphorylated form (p-RXR alpha) in HL-60 and HL-60R cells. 9-cis RA reduced both RXR alpha and p-RXR alpha in HL-60 cells, but did neither in HL-60R cells. However, when the HL-60R cells were treated with the combination of 9-cis RA plus PD98059, MEK inhibitor, the p-RXR alpha and RXR alpha proteins all markedly decreased. Moreover, the combination of those agents induced apoptosis in HL-60R cells. Phosphorylation of RXR alpha might be associated with RA-resistance in HL-60R cells.
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Affiliation(s)
- Nobuhiro Kanemura
- First Department of Internal Medicine, Gifu University Graduate School of Medicine, 1-1 Yanagido, Gifu 501-1194, Japan
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57
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Stubbs MC, Kim YM, Krivtsov AV, Wright RD, Feng Z, Agarwal J, Kung AL, Armstrong SA. MLL-AF9 and FLT3 cooperation in acute myelogenous leukemia: development of a model for rapid therapeutic assessment. Leukemia 2007; 22:66-77. [PMID: 17851551 PMCID: PMC2936245 DOI: 10.1038/sj.leu.2404951] [Citation(s) in RCA: 92] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Human leukemias harboring chromosomal translocations involving the mixed lineage leukemia (MLL, HRX, ALL-1) gene possess high-level expression, and frequent activating mutations of the receptor tyrosine kinase FLT3. We used a murine bone marrow transplant model to assess cooperation between MLL translocation and FLT3 activation. We demonstrate that MLL-AF9 expression induces acute myelogenous leukemia (AML) in approximately 70 days, whereas the combination of MLL-AF9 and FLT3-ITD does so in less than 30 days. Secondary transplantation of splenic cells from diseased mice established that leukemia stem cells are present at a very high frequency of approximately 1:100 in both diseases. Importantly, prospectively isolated granulocyte macrophage progenitors (GMPs) coinfected with MLL-AF9 and FLT3-ITD give rise to a similar AML, with shorter latency than from GMP transduced with MLL-AF9 alone. Cooperation between MLL-AF9 and FLT3-ITD was further verified by real-time assessment of leukemogenesis using noninvasive bioluminescence imaging. We used this model to demonstrate that MLL-AF9/FLT3-ITD-induced leukemias are sensitive to FLT3 inhibition in a 2-3 week in vivo assay. These data show that activated FLT3 cooperates with MLL-AF9 to accelerate onset of an AML from whole bone marrow as well as a committed hematopoietic progenitor, and provide a new genetically defined model system that should prove useful for rapid assessment of potential therapeutics in vivo.
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MESH Headings
- Animals
- Blotting, Southern
- Blotting, Western
- Bone Marrow Transplantation
- Cell Proliferation
- Disease Models, Animal
- Female
- Granulocytes/cytology
- Hematopoietic Stem Cells/cytology
- Hematopoietic Stem Cells/metabolism
- Humans
- Immunophenotyping
- Immunoprecipitation
- Leukemia, Myeloid, Acute/etiology
- Leukemia, Myeloid, Acute/pathology
- Luciferases/metabolism
- Macrophages/cytology
- Mice
- Mice, Inbred C57BL
- Mice, Transgenic
- Mutation
- Myeloid-Lymphoid Leukemia Protein/genetics
- Myeloid-Lymphoid Leukemia Protein/metabolism
- Oncogene Proteins, Fusion/genetics
- Oncogene Proteins, Fusion/metabolism
- Promoter Regions, Genetic
- Reverse Transcriptase Polymerase Chain Reaction
- Tandem Repeat Sequences
- Transfection
- Tumor Cells, Cultured
- fms-Like Tyrosine Kinase 3/genetics
- fms-Like Tyrosine Kinase 3/metabolism
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Affiliation(s)
- MC Stubbs
- Division of Hematology/Oncology, Children’s Hospital, Boston, MA, USA
| | - YM Kim
- Division of Hematology/Oncology, Children’s Hospital, Boston, MA, USA
| | - AV Krivtsov
- Division of Hematology/Oncology, Children’s Hospital, Boston, MA, USA
| | - RD Wright
- Department of Pediatric Oncology, Dana Farber Cancer Institute, Boston, MA, USA
| | - Z Feng
- Division of Hematology/Oncology, Children’s Hospital, Boston, MA, USA
| | - J Agarwal
- Division of Hematology/Oncology, Children’s Hospital, Boston, MA, USA
| | - AL Kung
- Division of Hematology/Oncology, Children’s Hospital, Boston, MA, USA
- Department of Pediatric Oncology, Dana Farber Cancer Institute, Boston, MA, USA
- Harvard Medical School, Boston, MA, USA
| | - SA Armstrong
- Division of Hematology/Oncology, Children’s Hospital, Boston, MA, USA
- Department of Pediatric Oncology, Dana Farber Cancer Institute, Boston, MA, USA
- Harvard Medical School, Boston, MA, USA
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58
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Neering SJ, Bushnell T, Sozer S, Ashton J, Rossi RM, Wang PY, Bell DR, Heinrich D, Bottaro A, Jordan CT. Leukemia stem cells in a genetically defined murine model of blast-crisis CML. Blood 2007; 110:2578-85. [PMID: 17601986 PMCID: PMC1988942 DOI: 10.1182/blood-2007-02-073031] [Citation(s) in RCA: 118] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Myeloid leukemia arises from leukemia stem cells (LSCs), which are resistant to standard chemotherapy agents and likely to be a major cause of drug-resistant disease and relapse. To investigate the in vivo properties of LSCs, we developed a mouse model in which the biologic features of human LSCs are closely mimicked. Primitive normal hematopoietic cells were modified to express the BCR/ABL and Nup98/HoxA9 translocation products, and a distinct LSC population, with the aberrant immunophenotype of lineage(-), Kit(+/-), Flt3(+), Sca(+), CD34(+), and CD150(-), was identified. In vivo studies were then performed to assess the response of LSCs to therapeutic insult. Treatment of animals with the ABL kinase inhibitor imatinib mesylate induced specific modulation of blasts and progenitor cells but not stem- cell populations, thereby recapitulating events inferred to occur in human chronic myelogenous leukemia (CML) patients. In addition, challenge of leukemic mice with total body irradiation was selectively toxic to normal hematopoietic stem cells (HSCs), suggesting that LSCs are resistant to apoptosis and/or senescence in vivo. Taken together, the system provides a powerful means by which the in vivo behavior of LSCs versus HSCs can be characterized and candidate treatment regimens can be optimized for maximal specificity toward primitive leukemia cells.
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Affiliation(s)
- Sarah J Neering
- James P Wilmot Cancer Center, University of Rochester Medical Center, NY 14642, USA
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59
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Horibe S, Takagi M, Unno J, Nagasawa M, Morio T, Arai A, Miura O, Ohta M, Kitagawa M, Mizutani S. DNA damage check points prevent leukemic transformation in myelodysplastic syndrome. Leukemia 2007; 21:2195-8. [PMID: 17495965 DOI: 10.1038/sj.leu.2404748] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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60
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Dong S, Kang S, Gu TL, Kardar S, Fu H, Lonial S, Khoury HJ, Khuri F, Chen J. 14-3-3 Integrates prosurvival signals mediated by the AKT and MAPK pathways in ZNF198-FGFR1-transformed hematopoietic cells. Blood 2007; 110:360-9. [PMID: 17389761 PMCID: PMC1896121 DOI: 10.1182/blood-2006-12-065615] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Human 8p11 stem cell leukemia/lymphoma syndrome usually presents as a myeloproliferative disorder (MPD) that evolves to acute myeloid leukemia and/or lymphoma. The syndrome associated with t(8;13)(p11;q12) results in expression of the ZNF198-FGFR1 fusion tyrosine kinase that plays a pathogenic role in hematopoietic transformation. We found that ZNF198-FGFR1 activated both the AKT and mitogen activated protein kinase (MAPK) prosurvival signaling pathways, resulting in elevated phosphorylation of the AKT target FOXO3a at T32 and BAD at S112, respectively. These phosphorylated residues subsequently sequestered the proapoptotic FOXO3a and BAD to 14-3-3 to prevent apoptosis. We used a peptide-based 14-3-3 competitive antagonist, R18, to disrupt 14-3-3-ligand association. Expression of R18 effectively induced apoptosis in hematopoietic Ba/F3 cells transformed by ZNF198-FGFR1 compared with control cells. Moreover, purified recombinant transactivator of transcription (TAT)-conjugated R18 proteins effectively transduced into human leukemia cells and induced significant apoptosis in KG-1a cells expressing FGFR1OP2-FGFR1 fusion tyrosine kinase but not in control HL-60 and Jurkat T cells. Surprisingly, R18 was only able to dissociate FOXO3a, but not BAD as previously proposed, from 14-3-3 binding and induced apoptosis partially through liberation and reactivation of FOXO3a. Our findings suggest that 14-3-3 integrates prosurvival signals in FGFR1 fusion-transformed hematopoietic cells. Disrupting 14-3-3-ligand association may represent an effective therapeutic strategy to treat 8p11 stem cell MPD.
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Affiliation(s)
- Shaozhong Dong
- Winship Cancer Institute, Emory University School of Medicine, Atlanta, GA 30322, USA
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61
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Agerstam H, Lilljebjörn H, Lassen C, Swedin A, Richter J, Vandenberghe P, Johansson B, Fioretos T. Fusion gene-mediated truncation ofRUNX1 as a potential mechanism underlying disease progression in the 8p11 myeloproliferative syndrome. Genes Chromosomes Cancer 2007; 46:635-43. [PMID: 17394134 DOI: 10.1002/gcc.20442] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
The 8p11 myeloproliferative syndrome (EMS) is a chronic myeloproliferative disorder molecularly characterized by fusion of various 5' partner genes to the 3' part of the fibroblast growth factor receptor 1 (FGFR1) gene at 8p, resulting in constitutive activation of the tyrosine kinase activity contained within FGFR1. EMS is associated with a high risk of transformation to acute myeloid leukemia (AML), but the mechanisms underlying the disease progression are unknown. In the present study, we have investigated a case of EMS harboring a t(8;22)(p11;q11)/BCR-FGFR1 rearrangement as well as a t(9;21)(q34;q22) at the time of AML transformation. FISH and RT-PCR analyses revealed that the t(9;21) leads to a fusion gene consisting of the 5' part of RUNX1 (exons 1-4) fused to repetitive sequences of a gene with unknown function on chromosome 9, adding 70 amino acids to RUNX1 exon 4. The t(9;21) hence results in a truncation of RUNX1. No point mutations were found in the other RUNX1 allele. The most likely functional outcome of the rearrangement was haploinsufficiency of RUNX1, which thus may be one mechanism by which EMS transforms to AML.
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Affiliation(s)
- Helena Agerstam
- Department of Clinical Genetics, Lund University Hospital, Lund, Sweden.
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62
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Nakajima H, Shibata F, Kumagai H, Shimoda K, Kitamura T. Tyk2 Is Dispensable for Induction of Myeloproliferative Disease by Mutant FLT3. Int J Hematol 2006; 84:54-9. [PMID: 16867903 DOI: 10.1532/ijh97.06016] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Internal tandem duplication of FLT3 tyrosine kinase (FLT3-ITD) is the most prevalent mutation found in acute myelogenous leukemia (AML), having been identified in 20% to 30% of all AML patients. We have previously shown that FLT3-ITD signals mainly through the signal transducer and activator of transcription 5 (STAT5) pathway and have suggested the possible involvement of Tyk2 in STAT5 activation by FLT3-ITD. The present study addressed the role of Tyk2 in FLT3-ITD signaling in a murine bone marrow transplantation (BMT) model. Transplantation of wild-type bone marrow cells transduced with the FLT3-ITD gene induced lethal myeloproliferative disease (MPD) in the recipient mice at a median latency of 89 days. Interestingly, some mice presented the proliferation of B- or T-lymphoid blasts in various organs, a presentation that resembled acute lymphoblastic leukemia (ALL). Mice that received Tyk2-deficient bone marrow cells transduced with FLT3-ITD developed lethal MPD with a disease latency (median, 100 days) and pathologic picture similar to those of mice that received wild-type bone marrow cells. These results indicate that (1) Tyk2 is not essential for MPD induction by FLT3-ITD and (2) FLT3-ITD by itself can induce ALL in a murine BMT model.
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Affiliation(s)
- Hideaki Nakajima
- Center of Excellence, Institute of Medical Science, University of Tokyo, Tokyo, Japan.
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63
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Roumier C, Lejeune-Dumoulin S, Renneville A, Goethgeluck AS, Philippe N, Fenaux P, Preudhomme C. Cooperation of activating Ras/rtk signal transduction pathway mutations and inactivating myeloid differentiation gene mutations in M0 AML: a study of 45 patients. Leukemia 2006; 20:433-6. [PMID: 16424869 DOI: 10.1038/sj.leu.2404097] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
According to a two hit model of leukaemogenesis, the association between acute myeloid leukaemia (AML)1 mutations and FLT3 gene alterations has been recently described in M0 AML. To further document this model in M0 AML, we screened a cohort of 45 patients to find an association between genes implicated in myeloid differentiation (AML1, Pu1) and genes contributing to cell proliferation: (FLT3, N-RAS, K-RAS, c-KIT, PTPN11). No mutation of the Pu1 gene was observed, whereas mutation in the Runt domain of AML1 gene was observed in 12 of 45 patients (27%). No point mutation or insertion-deletion in the c-kit gene was found. Three point mutations (7%) and 11 internal tandem duplications (22%) were seen in FLT3 gene. Two N-Ras and one PTPN11 mutations were found. No significant correlation between AML1 mutation and FLT3 alteration was found. On the other hand, abnormal cytogenetic findings, especially unfavourable ones, were significantly more frequent in patients without detectable molecular abnormality. These findings suggest at least two different pathogenetic pathways in M0 AML: one associated with AML1 mutation, sometimes in combination with the activating lesion of the tyrosine kinase pathway and generally with normal karyotype, and the other with unfavourable cytogenetic findings.
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Affiliation(s)
- C Roumier
- Laboratoire d'Hématologie A, CHU Lille, Lille, France
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64
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Banerji L, Sattler M. Targeting mutated tyrosine kinases in the therapy of myeloid leukaemias. Expert Opin Ther Targets 2006; 8:221-39. [PMID: 15161429 DOI: 10.1517/14728222.8.3.221] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Myeloid leukaemias are frequently associated with translocations and mutations of tyrosine kinase genes. The products of these oncogenes, including BCR-ABL, TEL-PDGFR, Flt3 and c-Kit, have elevated tyrosine kinase activity and transform haematopoietic cells, mainly by augmentation of proliferation and enhanced viability. Activated ABL kinases are associated with chronic myeloid leukaemia. Mutations in platelet-derived growth factor receptor beta are associated with chronic myelomonocytic leukaemia. Flt3 or c-Kit cooperate with other types of oncogenes to create fully transformed acute leukaemias. Elevated activity of these tyrosine kinases is crucial for transformation, thus making the kinase domain an ideal target for therapeutic intervention. Tyrosine kinase inhibitors for various kinases are currently being evaluated in clinical trials and are potentially useful therapeutic agents in myeloid leukaemias. Here, the authors review the signalling activities, mechanism of transformation and therapeutic targeting of several tyrosine kinase oncogenes important in myeloid leukaemias.
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Affiliation(s)
- Lolita Banerji
- Dana-Farber Cancer Institute, Department of Medical Oncology, Boston, MA 02115, USA
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65
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Shankar DB, Cheng JC, Sakamoto KM. Role of cyclic AMP response element binding protein in human leukemias. Cancer 2005; 104:1819-24. [PMID: 16196046 DOI: 10.1002/cncr.21401] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Acute myeloid leukemia (AML) in adults has a 20% 5-year disease-free survival despite treatment with aggressive cytotoxic chemotherapy. Previous work from our laboratory demonstrated that the majority of patients with acute lymphoid and myeloid leukemia overexpress CREB in the bone marrow. CREB overexpression is associated with poor initial outcome of clinical disease in AML patients. CREB is a transcription factor that functions in glucose homeostasis, growth-factor-dependent cell survival, and memory. Signaling by hematopoietic growth factors, such as GM-CSF, results in activation of CREB and up-regulation of CREB target genes. To study its role in hematopoiesis, we overexpressed CREB in leukemia cell lines and in mice. CREB overexpression resulted in increased survival and proliferation of myeloid cells and blast-transformation of bone marrow progenitor cells from transgenic mice expressing CREB in the myeloid lineage. CREB transgenic mice also develop myeloproliferative disease after 1 year. Thus, CREB acts as a protooncogene to regulate hematopoiesis and contributes to the leukemia phenotype. Our results suggest that CREB-dependent pathways may serve as targets for directed therapies in leukemia in the future.
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Affiliation(s)
- Deepa B Shankar
- Department of Pediatrics, Division of Hematology/Oncology, Gwynne Hazen Cherry Memorial Laboratories, and Mattel Children's Hospital, Jonsson Comprehensive Cancer Center, Los Angeles, California, USA
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66
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Abstract
Advances in molecular genetics have revolutionized our understanding of acute myeloid and lymphoblastic leukemia. Structural and numerical chromosomal aberrations are common, and their detection is vital for leukemia diagnosis, risk stratification, and monitoring of response to therapy. Fusion proteins resulting from chromosomal translocations are necessary but not sufficient for leukemogenesis, and there is intense research activity to elucidate the cooperating molecular abnormalities that may be suitable targets for novel therapeutic approaches. Candidate gene approaches have identified mutations in kinases and transcription factors in a proportion of patients, but more comprehensive genomic approaches are required. Gene expression profiling accurately classifies known subtypes of acute leukemia and has highlighted potentially leukemogenic abnormalities in gene expression. Newer techniques, such as single-nucleotide polymorphism arrays to analyze changes in gene copy number and zygosity, cancer genome sequencing, and RNA interference, are promising tools to identify mutations, although at present, data from these approaches are limited. This review provides an overview of these techniques in clinical practice and as research tools to develop new therapeutic approaches in pediatric leukemia.
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Affiliation(s)
- Charles G Mullighan
- Department of Pathology, St. Jude Children's Research Hospital, Memphis, Tennessee 38105, USA
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67
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Warner JK, Wang JCY, Takenaka K, Doulatov S, McKenzie JL, Harrington L, Dick JE. Direct evidence for cooperating genetic events in the leukemic transformation of normal human hematopoietic cells. Leukemia 2005; 19:1794-805. [PMID: 16094415 DOI: 10.1038/sj.leu.2403917] [Citation(s) in RCA: 92] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Although genetic abnormalities associated with hematological malignancies are readily identified, the natural history of human leukemia cannot be observed because initiating and subsequent transforming events occur before clinical presentation. Furthermore, it has not been possible to study leukemogenesis in vitro as normal human cells do not spontaneously transform. Thus, the nature and sequence of genetic changes required to convert human hematopoietic cells into leukemia cells have never been directly examined. We have developed a system where the first step in the leukemogenic process is an engineered disruption of differentiation and self-renewal due to expression of the TLS-ERG oncogene, followed in some cases by overexpression of hTERT. In two of 13 experiments, transduced cells underwent step-wise transformation and immortalization through spontaneous acquisition of additional changes. The acquired karyotypic abnormalities and alterations including upregulation of Bmi-1 and telomerase all occur in acute myeloid leukemia (AML), establishing the relevance of this system. One resultant cell line studied in depth exhibits cellular properties characteristic of AML, notably a hierarchical organization initiated by leukemic stem cells that differentiate abnormally. These findings provide direct evidence for multiple cooperating events in human leukemogenesis, and provide a foundation for studying the genetic changes that occur during leukemic initiation and progression.
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Affiliation(s)
- J K Warner
- Department of Molecular and Medical Genetics, University of Toronto, Toronto, Ontario, Canada
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68
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Yin X, Warner DR, Roberts EA, Pisano MM, Greene RM. Identification of novel CBP interacting proteins in embryonic orofacial tissue. Biochem Biophys Res Commun 2005; 329:1010-7. [PMID: 15752756 DOI: 10.1016/j.bbrc.2005.02.075] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2005] [Indexed: 02/02/2023]
Abstract
cAMP response element-binding protein (CREB)-binding protein (CBP) plays an important role as a general co-integrator of multiple signaling pathways and interacts with a large number of transcription factors and co-factors, through its numerous protein-binding domains. To identify nuclear factors associated with CBP in developing orofacial tissue, a yeast two-hybrid screen of a cDNA library derived from orofacial tissue from gestational day 11 to 13 mouse embryos was conducted. Using the carboxy terminus (amino acid residues 1676-2441) of CBP as bait, several novel proteins that bind CBP were identified, including an Msx-interacting-zinc finger protein, CDC42 interaction protein 4/thyroid hormone receptor interactor 10, SH3-domain GRB2-like 1, CCR4-NOT transcription complex subunit 3, adaptor protein complex AP-1 beta1 subunit, eukaryotic translation initiation factor 2B subunit 1 (alpha), and cyclin G-associated kinase. Results of the yeast two-hybrid screen were confirmed by glutathione S-transferase pull-down assays. The identification of these proteins as novel CBP-binding partners allows exploration of new mechanisms by which CBP regulates and integrates diverse cell signaling pathways.
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Affiliation(s)
- Xiaolong Yin
- Department of Molecular, Cellular and Craniofacial Biology, University of Louisville Birth Defects Center, ULSD Louisville, KY 40292, USA
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69
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Shankar DB, Cheng JC, Kinjo K, Federman N, Moore TB, Gill A, Rao NP, Landaw EM, Sakamoto KM. The role of CREB as a proto-oncogene in hematopoiesis and in acute myeloid leukemia. Cancer Cell 2005; 7:351-62. [PMID: 15837624 DOI: 10.1016/j.ccr.2005.02.018] [Citation(s) in RCA: 193] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/05/2004] [Revised: 11/24/2004] [Accepted: 02/24/2005] [Indexed: 11/21/2022]
Abstract
CREB is a transcription factor that functions in glucose homeostasis, growth factor-dependent cell survival, and memory. In this study, we describe a role of CREB in human cancer. CREB overexpression is associated with increased risk of relapse and decreased event-free survival. CREB levels are elevated in blast cells from patients with acute myeloid leukemia. To understand the role of CREB in leukemogenesis, we studied the biological consequences of CREB overexpression in primary human leukemia cells, leukemia cell lines, and transgenic mice. Our results demonstrate that CREB promotes abnormal proliferation and survival of myeloid cells in vitro and in vivo through upregulation of specific target genes. Thus, we report that CREB is implicated in myeloid cell transformation.
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Affiliation(s)
- Deepa B Shankar
- Division of Hematology/Oncology, Department of Pediatrics, Gwynne Hazen Cherry Memorial Laboratories and Mattel Children's Hospital, Jonsson Comprehensive Cancer Center, David Geffen School of Medicine at UCLA, Los Angeles, California 90095, USA
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70
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Jordan CT, Guzman ML. Mechanisms controlling pathogenesis and survival of leukemic stem cells. Oncogene 2004; 23:7178-87. [PMID: 15378078 DOI: 10.1038/sj.onc.1207935] [Citation(s) in RCA: 93] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Stem cells are an integral component of normal mammalian physiology and have been intensively studied in many systems. Intriguingly, substantial evidence indicates that stem cells also play an important role in the initiation and pathogenesis of at least some cancers. In particular, myeloid leukemias have been extensively characterized with regard to stem and progenitor cell involvement. Thus, as a focal point for both scientific and therapeutic endeavors, leukemic stem cells (LSC) represent a critical area of investigation. LSC appear to retain many characteristics of normal hematopoietic stem cells (HSC) as evidenced by a hierarchical developmental pattern, a mostly quiescent cell cycle profile, and an immunophenotype very similar to HSC. Consequently, defining unique properties of LSC remains a high priority in order to elucidate the molecular mechanisms driving stem cell transformation, and for developing therapeutic strategies that specifically target the LSC population. In this review, we discuss emerging concepts in the field and describe how various molecular and cellular characteristics of leukemia cells might be exploited as a means to preferentially ablate malignant stem cells.
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Affiliation(s)
- Craig T Jordan
- Department of Medicine, University of Rochester Medical Center, 601 Elmwood Avenue, Box 703, NY 14642, USA.
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71
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Abstract
Two fundamental problems in cancer research are identification of the normal cell within which cancer initiates and identification of the cell type capable of sustaining the growth of the neoplastic clone. There is overwhelming evidence that virtually all cancers are clonal and represent the progeny of a single cell. What is less clear for most cancers is which cells within the tumor clone possess tumorigenic or 'cancer stem cell' (CSC) properties and are capable of maintaining tumor growth. The concept that only a subpopulation of rare CSC is responsible for maintenance of the neoplasm emerged nearly 50 years ago. Testing of this hypothesis is most advanced for the hematopoietic system due to the establishment of functional in vitro and in vivo assays for stem and progenitor cells at all stages of development. This body of work led to conclusive proof for CSC with the identification and purification of leukemic stem cells capable of repopulating NOD/SCID mice. This review will focus on the historical development of the CSC hypothesis, the mechanisms necessary to subvert normal developmental programs, and the identification of the cell in which these leukemogenic events first occur.
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Affiliation(s)
- Jennifer K Warner
- Division of Cell and Molecular Biology, University Health Network, University of Toronto, 620 University Ave, ON M5G 2C1, Canada
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72
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Abstract
Given the unique abilities of a stem cell to self-renew, differentiate, and proliferate, it is no wonder that they are critically important to an organism during development and to maintain homeostasis. Likewise, when something goes awry within a stem cell, it is likely to have far-reaching effects, since stem cells persist throughout the lifetime of the individual. Two significant biological phenomena that involve stem cells are the inevitable process of aging and a major health issue whose incidence increases with aging: cancer. In this review, we summarize evidence and theories concerning these two stem cell processes. The inability of stem cells to be passaged indefinitely in mice and the data supporting regular replication of the quiescent stem cell pool are discussed. Further, the current evidence indicating a stem cell origin of acute myeloid leukemia, including examples from both experimental mouse models and human clinical samples, is evaluated. Finally, we propose a model in which aging of the stem cell population of the hematopoietic system in particular can create conditions that are permissive to leukemia development; in fact, we suggest that aging is a secondary event in leukemogenesis.
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Affiliation(s)
- Deborah R Bell
- Department of Internal Medicine, Markey Cancer Center, University of Kentucky, Lexington 40536-0093, USA
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73
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Braess J, Schneiderat P, Schoch C, Fiegl M, Lorenz I, Hiddemann W. Functional analysis of apoptosis induction in acute myeloid leukaemia-relevance of karyotype and clinical treatment response. Br J Haematol 2004; 126:338-47. [PMID: 15257705 DOI: 10.1111/j.1365-2141.2004.05039.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Deficiencies or structural defects of the apoptotic machinery have been postulated as a potential mechanism for a broad resistance of acute myeloid leukaemia (AML) blasts towards cytotoxic therapy comprising chemotherapeutic agents with diverse pharmacodynamic principles but also cell-mediated cytotoxicity of the graft-versus-leukaemia effect, for example, in the setting of allogeneic transplantation. This hypothesis was systematically tested by functionally analysing the early, intermediate and late events of the apoptotic process in primary AML (n = 31) blasts following activation of the intrinsic and extrinsic pathway of apoptosis (etoposide and cytarabine as DNA damaging agents, FAS-ligand as an activator of the death receptor pathway). Activation of the extrinsic pathway by FAS-ligand did not induce apoptosis in primary AML, instead the proapoptotic signal was shown to 'fade', even in the early phase of the apoptotic sequence. However, activation of the intrinsic pathway induced severe cytotoxicity in all samples that showed the characteristic features of typical apoptosis, with a prominent apoptotic volume decrease (blebbing) in the early phase, significant increases in caspase 3 activity (intermediate or effector phase) and breakdown of cellular energy production in the late phase of apoptosis. These characteristics did not differ between prognostically favourable versus unfavourable AML karyotypes or between clinically responding versus refractory AML--indicating that a functional apoptotic apparatus is present even in the unfavourable AML subgroups. Our data indicate that the mechanism for a broad clinical resistance is not a dysfunctional apparatus per se but rather the consequence of anti-apoptotic regulation impeding otherwise functional apoptotic machinery.
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Affiliation(s)
- Jan Braess
- Department of Internal Medicine III, University Hospital Grosshadern, Ludwig-Maximilians University, Munich, Germany.
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74
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Affiliation(s)
- B Göttgens
- Department of Haematology, Cambridge University, Cambridge Institute for Medical Research, Hills Road, Cambridge CB2 2XY, UK.
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75
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Sperr WR, Hauswirth AW, Florian S, Ohler L, Geissler K, Valent P. Human leukaemic stem cells: a novel target of therapy. Eur J Clin Invest 2004; 34 Suppl 2:31-40. [PMID: 15291804 DOI: 10.1111/j.0960-135x.2004.01368.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Acute myeloid leukaemia (AML) is a life-threatening haematopoietic disease that is characterized by clonal growth and the accumulation of myelopoietic progenitor cells. Although AML cells only have a limited potential to undergo differentiation and maturation, each AML clone is organized in a hierarchical manner similar to normal haematopoiesis. Recent data have shown that each AML clone consists of leukaemic stem cells and their progeny, and that AML stem cells differ from more mature cells in several aspects, including survival and target antigen profiles. Most importantly, AML stem cells, but not their progeny, have the capacity to repopulate haematopoietic tissues with leukaemias in NOD/SCID mice. Furthermore, AML stem cells are thought to be responsible for the infinite growth of leukaemias in patients with AML. The phenotypic properties of AML stem cells have also been described. In most cases, these cells are detectable within the CD34+, CD38-, Lin-, CD123+ subpopulation of AML cells. Because of their AML-initiating and -renewing capacity and their unique phenotype, which includes several molecular targets of drug therapy, AML stem cells have recently been proposed as novel important target cell populations in the context of curative therapies. The present article gives an overview of our knowledge about AML stem cells, their phenotype, and their role as a 'therapy-target' in new concepts to treat and to cure patients with AML.
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Affiliation(s)
- W R Sperr
- Department of Internal Medicine I, Division of Hematology & Hemostaseology, Medical University of Vienna, Austria.
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76
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Shankar DB, Sakamoto KM. The role of cyclic-AMP binding protein (CREB) in leukemia cell proliferation and acute leukemias. Leuk Lymphoma 2004; 45:265-70. [PMID: 15101710 DOI: 10.1080/1042819031000151095] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Leukemia is a result of accumulating genetic alterations. The collaboration of mutations that offer survival and proliferative signals, together with mutations that result in lack of differentiation, is thought to cause a leukemic phenotype. The cyclic-AMP Response Element Binding Protein (CREB) is a transcription factor that is known to be a downstream component of the GM-CSF and IL-3 signaling pathways. We previously showed that CREB is overexpressed in blast cells from patients with acute leukemias. In this paper, we review the role of CREB in hematopoiesis, cell proliferation and acute leukemias.
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Affiliation(s)
- Deepa B Shankar
- Division of Hematology-Oncology, Gwynne-Hazen Cherry Memorial Laboratories, Mattel Children's Hospital, Los Angeles, CA 90095-1752, USA
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77
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Chen J, Wall NR, Kocher K, Duclos N, Fabbro D, Neuberg D, Griffin JD, Shi Y, Gilliland DG. Stable expression of small interfering RNA sensitizes TEL-PDGFbetaR to inhibition with imatinib or rapamycin. J Clin Invest 2004; 113:1784-91. [PMID: 15199413 PMCID: PMC420507 DOI: 10.1172/jci20673] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2003] [Accepted: 03/30/2004] [Indexed: 11/17/2022] Open
Abstract
Small molecule inhibitors, such as imatinib, are effective therapies for tyrosine kinase fusions BCR-ABL-TEL-PDGFbetaR-mediated human leukemias, but resistance may develop. The unique fusion junctions of these molecules are attractive candidates for molecularly targeted therapeutic intervention using RNA interference (RNAi), which is mediated by small interfering RNA (siRNA). We developed a retroviral system for stable expression of siRNA directed to the unique fusion junction sequence of TEL-PDGFbetaR in transformed hematopoietic cells. Stable expression of the siRNA resulted in approximately 90% inhibition of TEL-PDGFbetaR expression and its downstream effectors, including PI3K and mammalian target of rapamycin (mTOR). Expression of TEL-PDGFbetaR-specific siRNA (TPsiRNA) significantly attenuated the proliferation of TEL-PDGFbetaR-transformed Ba/F3 cells or disease latency and penetrance in mice induced by intravenous injection of these Ba/F3 cells. Although a 90% reduction in TEL-PDGFbetaR expression was insufficient to induce cell death, stable siRNA expression sensitized transformed cells to the PDGFbetaR inhibitor imatinib or to the mTOR inhibitor rapamycin. TPsiRNA also inhibited an imatinib-resistant TEL-PDGFbetaR mutant, and the inhibition was enhanced by siRNA in combination with PKC412, another PDGFbetaR inhibitor. Although siRNA delivery in vivo is a challenging problem, stable expression of siRNA, which targets oncogenic fusion genes, may potentiate the effects of conventional therapy for hematologic malignancies.
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Affiliation(s)
- Jing Chen
- Howard Hughes Medical Institute, Division of Hematology, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts 02115, USA
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78
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Chen J, Wall NR, Kocher K, Duclos N, Fabbro D, Neuberg D, Griffin JD, Shi Y, Gilliland DG. Stable expression of small interfering RNA sensitizes TEL-PDGFbetaR to inhibition with imatinib or rapamycin. J Clin Invest 2004. [PMID: 15199413 DOI: 10.1172/jci200420673] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Small molecule inhibitors, such as imatinib, are effective therapies for tyrosine kinase fusions BCR-ABL-TEL-PDGFbetaR-mediated human leukemias, but resistance may develop. The unique fusion junctions of these molecules are attractive candidates for molecularly targeted therapeutic intervention using RNA interference (RNAi), which is mediated by small interfering RNA (siRNA). We developed a retroviral system for stable expression of siRNA directed to the unique fusion junction sequence of TEL-PDGFbetaR in transformed hematopoietic cells. Stable expression of the siRNA resulted in approximately 90% inhibition of TEL-PDGFbetaR expression and its downstream effectors, including PI3K and mammalian target of rapamycin (mTOR). Expression of TEL-PDGFbetaR-specific siRNA (TPsiRNA) significantly attenuated the proliferation of TEL-PDGFbetaR-transformed Ba/F3 cells or disease latency and penetrance in mice induced by intravenous injection of these Ba/F3 cells. Although a 90% reduction in TEL-PDGFbetaR expression was insufficient to induce cell death, stable siRNA expression sensitized transformed cells to the PDGFbetaR inhibitor imatinib or to the mTOR inhibitor rapamycin. TPsiRNA also inhibited an imatinib-resistant TEL-PDGFbetaR mutant, and the inhibition was enhanced by siRNA in combination with PKC412, another PDGFbetaR inhibitor. Although siRNA delivery in vivo is a challenging problem, stable expression of siRNA, which targets oncogenic fusion genes, may potentiate the effects of conventional therapy for hematologic malignancies.
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Affiliation(s)
- Jing Chen
- Howard Hughes Medical Institute, Division of Hematology, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts 02115, USA
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79
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Sattler M, Scheijen B, Weisberg E, Griffin JD. Mutated tyrosine kinases as therapeutic targets in myeloid leukemias. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2004; 532:121-40. [PMID: 12908554 DOI: 10.1007/978-1-4615-0081-0_11] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Tyrosine kinases are commonly mutated and activated in both acute and chronic myeloid leukemias. Here, we review the functions, signaling activities, mechanism of transformation, and therapeutic targeting of two prototypic tyrosine kinase oncogenes, BCR-ABL and FLT3, associated with chronic myeloid leukemia (CML) and acute myeloid leukemia (AML), respectively. BCR-ABL is generated by the Philadelphia chromosome translocation between chromosomes 9 and 22, creating a chimeric oncogene in which the BCR and c-ABL genes are fused. The product of this oncogene, BCR-ABL, has elevated ABL tyrosine kinase activity and transforms hematopoietic cells by exerting a wide variety of biological effects, including reduction in growth factor dependence, enhanced viability, and altered adhesion of chronic myelocytic leukemia (CML) cells. Elevated tyrosine kinase activity of BCR-ABL is critical for activating downstream signalling cascades and for all aspects of transformation, explaining the remarkable clinical efficacy of the tyrosine kinase inhibitor, imatinib mesylate (STI571). By comparison, FLT3 is mutated in about one third of all cases of AML, most often through a mechanism that involves an internal tandem duplication (ITD) of a small number of amino acid residues in the juxtamembrane domain of the receptor. As is the case for BCR-ABL, these mutations activate the kinase activity constitutively, activate multiple signaling pathways, and result in an augmentation of proliferation and viability. Transformation by FLT3-ITD can readily be observed in murine models, and FLT3 cooperates with other types of oncogenes to create a fully transformed acute leukemia. FLT3 tyrosine kinase inhibitors are currently being evaluated in clinical trials and may be very useful therapeutic agents in AML.
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Affiliation(s)
- Martin Sattler
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA 02115, USA
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80
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Hsieh JJD, Cheng EHY, Korsmeyer SJ. Taspase1: a threonine aspartase required for cleavage of MLL and proper HOX gene expression. Cell 2004; 115:293-303. [PMID: 14636557 DOI: 10.1016/s0092-8674(03)00816-x] [Citation(s) in RCA: 209] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The Mixed-Lineage Leukemia gene (MLL/HRX/ALL1) encodes a large nuclear protein homologous to Drosophila trithorax that is required for the maintenance of HOX gene expression. MLL is cleaved at two conserved sites generating N320 and C180 fragments, which heterodimerize to stabilize the complex and confer its subnuclear destination. Here, we purify and clone the protease responsible for cleaving MLL. We entitle it Taspase1 as it initiates a class of endopeptidases that utilize an N-terminal threonine as the active site nucleophile to proteolyze polypeptide substrates following aspartate. Taspase1 proenzyme is intramolecularly proteolyzed generating an active 28 kDa alpha/22 kDa beta heterodimer. RNAi-mediated knockdown of Taspase1 results in the appearance of unprocessed MLL and the loss of proper HOX gene expression. Taspase1 coevolved with MLL/trithorax as Arthropoda and Chordata emerged from Metazoa suggesting that Taspase1 originated to regulate complex segmental body plans in higher organisms.
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Affiliation(s)
- James J-D Hsieh
- Howard Hughes Medical Institute, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA 02115, USA
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81
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Abstract
Abstract
Major strides have been made in our understanding of the molecular basis of adult and pediatric leukemias. More than one hundred disease alleles have been identified and characterized in cell culture and murine models of leukemia. In some instances, molecularly targeted therapies have been developed based on these insights that are currently in clinical trials, such as small molecule inhibitors of FLT3. In addition, it has recently been appreciated that, as with normal hematopoiesis, there is a hierarchical organization among leukemic cells that includes a rare population of leukemic stem cells that have properties of self-renewal. Understanding the characteristics of these leukemic stem cells may provide new insights into leukemia therapies that target self-renewal pathways.
In Section I, Dr. Craig Jordan reviews the data that supports the existence of a “leukemia stem cell.” He provides an overview of the functional properties of leukemic stem cells, their relationship to hematopoietic stem cells, and the relevance of leukemic stem cells in other human malignancies including solid tumors. He briefly discusses what is known of the pathways that regulate properties of self-renewal.
Dr. Gary Gilliland provides an overview of the genetics of adult leukemias in Section II and ongoing genome-wide strategies for discovery of new disease alleles. He describes the clinical and therapeutic implications of these findings and provides examples of bench-to-bedside translation of molecularly targeted therapies for AML, including the use of FLT3 inhibitors.
In Section III, Dr. Carolyn Felix reviews recent advances in our understanding of the genetics and therapy of pediatric leukemias. She provides an overview of leukemias that are common in pediatric malignancies but rarely observed in adults, including the TEL-AML1 (ETV6-RUNX1) fusion associated with pediatric B-cell ALL, the OTT-MAL fusion associated with infant megakaryoblastic leukemia, PTPN11 mutations in juvenile myelomonocytic leukemia, and MLL fusion genes in leukemogenesis, among others.
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Affiliation(s)
- D Gary Gilliland
- Brigham and Women's Hospital, Howard Hughes Medical Institute, Harvard Medical School, Boston, MA 02115, USA
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82
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Fine BM, Stanulla M, Schrappe M, Ho M, Viehmann S, Harbott J, Boxer LM. Gene expression patterns associated with recurrent chromosomal translocations in acute lymphoblastic leukemia. Blood 2003; 103:1043-9. [PMID: 14525776 DOI: 10.1182/blood-2003-05-1518] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We obtained a global view of gene expression in both cell lines and pediatric acute lymphoblastic leukemia (ALL) samples that harbor one of several selected chromosomal abnormalities. When the cell lines were studied alone, we found that these chromosomal abnormalities were associated with the predominant variation in transcriptional programs across the set of cell lines studied. When cell lines and clinical samples were studied together, we found that each chromosomal abnormality (TEL/AML1, BCR/ABL, or MLL abnormalities) was associated with a characteristic gene expression signature that was shared by both cell lines and clinical samples. However, BCR/ABL was associated with a much more heterogeneous pattern of expression than were TEL/AML1 and MLL abnormalities. This observation has important implications for the study of BCR/ABL ALL. In addition, we systematically identified genes whose expression was associated with TEL/AML1, BCR/ABL, or MLL abnormalities in both clinical samples and cell lines. Although some of these genes have previously been described, many have not previously been reported to be associated with one of these chromosomal abnormalities. Notably, we found that the erythropoietin receptor (EPOR) is consistently highly expressed in TEL/AML1 ALL compared with BCR/ABL or MLL.
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Affiliation(s)
- Bernard M Fine
- Division of Hematology, 269 Campus Dr, CCSR 1155, Stanford University School of Medicine, Stanford, CA 94305-5156, USA.
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83
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Xu Q, Simpson SE, Scialla TJ, Bagg A, Carroll M. Survival of acute myeloid leukemia cells requires PI3 kinase activation. Blood 2003; 102:972-80. [PMID: 12702506 DOI: 10.1182/blood-2002-11-3429] [Citation(s) in RCA: 353] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The mechanisms that regulate the growth and survival of acute myeloid leukemia (AML) cells are largely unknown. We hypothesized that constitutive activation of phosphatidyl-inositide 3 kinase (PI3 kinase) could regulate survival in primary cells from patients with AML. Here we demonstrate that Akt, a critical substrate of PI3 kinase, is activated in AML blasts. In a short-term culture system, most AML patient samples showed a dose-dependent decrease in survival after incubation with the PI3 kinase inhibitor LY294002. This decrease in survival was partially due to the induction of apoptosis. Furthermore, we have shown that p70 S6 kinase and 4EBP-1, downstream mediators of Akt signaling, also are phosphorylated in AML blasts. Phosphorylation of these proteins is inhibited by the mTOR inhibitor RAD001. Incubation of AML blasts with RAD001 induces only a small decrease in survival of the cells; however, when combined with Ara-C, RAD001 enhances the toxicity of Ara-C. These results demonstrate that constitutive activation of the PI3 kinase pathway is necessary for the survival of AML blasts and that targeting of this pathway with pharmacologic inhibitors may be of clinical benefit in treatment of AML.
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Affiliation(s)
- Qing Xu
- Division of Hematology and Oncology, University of Pennsylnvania, Philadelphia, PA 19104, USA
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84
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Wallace J, Zhou Y, Usmani GN, Reardon M, Newburger P, Woda B, Pihan G. BARCODE-ALL: accelerated and cost-effective genetic risk stratification in acute leukemia using spectrally addressable liquid bead microarrays. Leukemia 2003; 17:1404-10. [PMID: 12835731 DOI: 10.1038/sj.leu.2402985] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
An increasing number of risk-stratifying genetic lesions in acute leukemia are being discovered and characterized. To translate this important and increasing volume of information from the research laboratory into effective clinical care, however, new, fast and comprehensive assays are needed. Toward this end, we have developed a two-stage multiplexing assay of broad applicability, which combines multiplex polymerase chain reaction with multiplex detection on spectrally addressable liquid bead microarrays. Using pediatric lymphoblastic leukemia as a model system, we demonstrate that all seven of the fusion transcripts resulting from risk-stratifying chromosomal translocations can be assayed in a single well of a 96-well multiplate with 100% specificity and sensitivity, within 6 h of specimen collection. The assay is automatic and high throughput and represents a significant improvement over previously available assays targeting the same genetic changes. We conclude that user-defined assays that multiplex both target selection and detection may have broad applicability in the management of hematological malignancies.
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Affiliation(s)
- J Wallace
- Laboratory of Molecular Diagnostics, University of Massachusetts Medical School and Umass Memorial Health Care, University Campus, Worcester, MA 02215, USA
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85
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Taghon T, Thys K, De Smedt M, Weerkamp F, Staal FJT, Plum J, Leclercq G. Homeobox gene expression profile in human hematopoietic multipotent stem cells and T-cell progenitors: implications for human T-cell development. Leukemia 2003; 17:1157-63. [PMID: 12764384 DOI: 10.1038/sj.leu.2402947] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Class I homeobox (HOX) genes comprise a large family of transcription factors that have been implicated in normal and malignant hematopoiesis. However, data on their expression or function during T-cell development is limited. Using degenerated RT-PCR and Affymetrix microarray analysis, we analyzed the expression pattern of this gene family in human multipotent stem cells from fetal liver (FL) and adult bone marrow (ABM), and in T-cell progenitors from child thymus. We show that FL and ABM stem cells are similar in terms of HOX gene expression, but significant differences were observed between these two cell types and child thymocytes. As the most immature thymocytes are derived from immigrated FL and ABM stem cells, this indicates a drastic change in HOX gene expression upon entry into the thymus. Further analysis of HOX-A7, HOX-A9, HOX-A10, and HOX-A11 expression with specific RT-PCR in all thymocyte differentiation stages showed a sequential loss of 3' region HOX-A cluster genes during intrathymic T-cell development and an unexpected expression of HOX-A11, previously not recognized to play a role in hematopoiesis. Also HOX-B3 and HOX-C4 were expressed throughout thymocyte development. Overall, these data provide novel evidence for an important role of certain HOX genes in human T-cell development.
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Affiliation(s)
- T Taghon
- Department of Clinical Chemistry, Microbiology and Immunology, Ghent University Hospital, De Pintelaan 185, Ghent B-9000, Belgium
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86
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Jantunen E, Mahlamäki E, Heinonen K, Nousiainen T. Multiple complete remissions in a patient with acute myeloid leukemia (M4eo) with low-dose cytosine arabinoside and all-trans retinoic acid. Leuk Lymphoma 2003; 44:883-5. [PMID: 12802931 DOI: 10.1080/1042819021000055011] [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: 10/27/2022]
Abstract
A 54-year-old female with acute myeloid leukemia (AML) (FAB M4eo) was treated at second relapse with a combination of low-dose cytosine arabinoside (LDAraC) (20 mg b.i.d. subcutaneously) and all-trans retinoic acid (ATRA) (45 mg/m2/d orally) on days 1-10. The patient achieved a complete hematological remission after the first cycle and was consolidated with three similar cycles at four-week intervals. Subsequently, the patient relapsed several times. Altogether seven complete hematological remissions including some cytogenetic remissions were induced with the same regimen. The patient survived 81 months after the start with LDAraC-ATRA regimen. This low-toxicity regimen may be useful in some patients with poor-risk AML.
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Affiliation(s)
- E Jantunen
- Department of Medicine, Kuopio University Hospital, P.O.B. 1777, 70211 Kuopio, Finland.
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87
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Bagg A. Clinical applications of molecular genetic testing in hematologic malignancies: advantages and limitations. Hum Pathol 2003; 34:352-8. [PMID: 12733115 DOI: 10.1053/hupa.2003.100] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Adam Bagg
- Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, PA 19104-4283, USA
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88
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Abstract
Human leukemias are typified by acquired recurring chromosomal translocations. Cloning of these translocation breakpoints has provided important insights into pathogenesis of disease as well as novel therapeutic approaches. Chronic myelogenous leukemias (CML) are caused by constitutively activated tyrosine kinases, such as BCR/ABL, that confer a proliferative and survival advantage to hematopoietic progenitors but do not affect differentiation. These activated kinases are validated targets for therapy with selective tyrosine kinase inhibitors, a paradigm that may have broad applications in treatment of hematologic malignancies as well as solid tumors. Chromosomal translocations in acute myeloid leukemias (AML) most often result in loss-of-function mutations in transcription factors that are required for normal hematopoietic development. These latter mutations, however, are not sufficient to cause AML. The available evidence indicates that activating mutations in the hematopoietic tyrosine kinases FLT3 and c-KIT, and in N-RAS and K-RAS, confer proliferative advantage to hematopoietic progenitors and cooperate with loss-of-function mutations in hematopoietic transcription factors to cause an acute leukemia phenotype characterized by proliferation and impaired differentiation. The data supporting this hypothesis and the clinical and therapeutic implications of these observations are reviewed.
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Affiliation(s)
- Louise M Kelly
- Howard Hughes Medical Institute, Brigham and Women's Hospital, Harvard Institutes of Medicine, Harvard Medical School, Boston, Massachusetts 02115, USA.
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89
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Lutz PG, Moog-Lutz C, Cayre YE. Signaling revisited in acute promyelocytic leukemia. Leukemia 2002; 16:1933-9. [PMID: 12357345 DOI: 10.1038/sj.leu.2402728] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2002] [Accepted: 07/03/2002] [Indexed: 11/09/2022]
Abstract
Although transcription factors are still the main focus to understanding leukemogenesis, recent results strongly suggest that alteration of a receptor and/or subsequent signaling plays a critical and co-operative role in the pathogenesis of acute myeloid leukemia (AML). The t(15;17) translocation, found in 95% of APL, encodes a PML-RARalpha fusion protein. A main model proposed for acute promyelocytic leukemia (APL) is that PML-RARalpha exerts its oncogenic effects by repressing retinoic acid-inducible genes critical to myeloid differentiation. Dysregulation of these genes may result in abnormal signaling, thereby freeing pre-leukemic cells from controls which normally induce the onset of differentiation. It is also likely that treatment of APL cells by retinoic acid induces de novo up-regulation of the same genes which are dominantly repressed by PML-RARalpha and whose expression is required for reactivation of the differentiation program. Identification of such genes together with the signaling pathways interrupted at the early stages of leukemia transformation and reactivated during retinoic acid-induced differentiation in APL cells will contribute to the development of new molecular targets for treatment of leukemia.
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MESH Headings
- Chromosomes, Human, Pair 15
- Chromosomes, Human, Pair 17
- Humans
- Leukemia, Promyelocytic, Acute/genetics
- Leukemia, Promyelocytic, Acute/metabolism
- Leukemia, Promyelocytic, Acute/pathology
- Signal Transduction
- Translocation, Genetic
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Affiliation(s)
- P G Lutz
- Unité INSERM U417, Hôpital Saint Antoine, Paris, France
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90
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Abstract
Significant advances have occurred in understanding the molecular pathogenesis of human leukemias. Analysis of patient karyotypes reveals that nonrandom, somatically acquired translocations and inversions occur in most acute myeloid leukemias. Among these, fusion oncogenes have been identified that utilize similar signal transduction pathways and transcriptional activation pathways to mediate their leukemogeneic effect. In chronic myeloid leukemia (CML), both in vitro and in vivo animal studies show that BCR-AB expression leads to clinical manifestations of CML, demonstrating that BCR-AB and its fusion proteins are central mediators of myeloid proliferation and transformation in these malignancies. In other CML syndromes (chronic myelomonocytic leukemia, atypical CML), cloning of chromosomal translocation breakpoints has identified a spectrum of constitutively activated tyrosine kinases. These tyrosine kinase fusions alone apparently are both necessary and sufficient to recapitulate the disease phenotype in the murine model. In contrast, acute myelogenous leukemia (AML) is typified by chromosomal translocations involving transcription factors needed for normal myeloid differentiation. The functional consequence of translocations is loss of function of these transcription factors, resulting in impaired myeloid differentiation. However, these alone are not sufficient to cause acute leukemia; evidence strongly supports the hypothesis that second mutations are required. Data suggest a multistep pathogenesis for AML in which class I mutations, such as activating point mutations in receptor tyrosine kinases (eg, FLT3 and c-KIT), provide a proliferative and/or survival signal to hematopoietic progenitors. Class II mutations are those targeting hematopoietic transcription factors and serving primarily to impair differentiation and subsequent apoptosis. Together, these mutations result in leukemic cells capable of proliferation and survival but not differentiation. The clinical and therapeutic implication is that it may be possible to target both classes of mutations using selected or screened small-molecule inhibitors. Insights gained from molecular genetic analysis of AML provide the basis for a rational, targeted therapeutic approach.
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Affiliation(s)
- D Gary Gilliland
- Howard Hughes Medical Institute, Brigham & Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
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91
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Grimwade D, Lo Coco F. Acute promyelocytic leukemia: a model for the role of molecular diagnosis and residual disease monitoring in directing treatment approach in acute myeloid leukemia. Leukemia 2002; 16:1959-73. [PMID: 12357347 DOI: 10.1038/sj.leu.2402721] [Citation(s) in RCA: 114] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2002] [Accepted: 06/21/2002] [Indexed: 11/08/2022]
Abstract
Acute promyelocytic leukemia (APL) is characterized by a number of features that underpin the need for rapid and accurate diagnosis and demand a highly specific treatment approach. These include the potentially devastating coagulopathy, sensitivity to anthracycline-based chemotherapy regimens, as well as unique responses to all-trans retinoic acid and arsenic trioxide that have revolutionized therapy over the last decade. The chromosomal translocation t(15;17) which generates the PML-RARalpha fusion gene has long been considered the diagnostic hallmark of APL; however, this abnormality is not detected in approximately 10% cases with successful karyotype analysis. In the majority of these cases, the PML-RARalpha fusion gene is still formed, resulting from insertion events or more complex rearrangements. These cases share the beneficial response to retinoids and favorable prognosis of those with documented t(15;17), underscoring the clinical relevance of molecular analyses in diagnostic refinement. In other cases of t(15;17) negative APL, various chromosomal rearrangements involving 17q21 have been documented leading to fusion of RARalpha to alternative partners, namely PLZF, NPM, NuMA and STAT5b. The nature of the fusion partner has a significant bearing upon disease characteristics, including sensitivity to retinoids and arsenic trioxide. APL has provided an exciting treatment model for other forms of AML whereby therapeutic approach is directed towards cytogenetically and molecularly defined subgroups and further modified according to response as determined by minimal residual disease (MRD) monitoring. Recent studies suggest that rigorous MRD monitoring, coupled with pre-emptive therapy at the point of molecular relapse improves survival in the relatively small subgroup of PML-RARalpha positive patients with 'poor risk' disease. Advent of 'real-time' quantitative RT-PCR technology seems set to yield further improvements in the predictive value of MRD assessment, achieve more rapid sample throughput and facilitate inter- and intra-laboratory standardization, thereby enabling more reliable comparison of data between international trial groups.
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MESH Headings
- Acute Disease
- Chromosomes, Human, Pair 15
- Chromosomes, Human, Pair 17
- Humans
- Leukemia, Myeloid/therapy
- Leukemia, Promyelocytic, Acute/diagnosis
- Leukemia, Promyelocytic, Acute/genetics
- Leukemia, Promyelocytic, Acute/therapy
- Monitoring, Physiologic
- Neoplasm, Residual
- Translocation, Genetic
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Affiliation(s)
- D Grimwade
- Division of Medical and Molecular Genetics, Guy's, King's and St Thomas' School of Medicine, London, UK
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92
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Abstract
FLT3 is a receptor tyrosine kinase expressed by immature hematopoietic cells and is important for the normal development of stem cells and the immune system. The ligand for FLT3 is expressed by marrow stromal cells and other cells and synergizes with other growth factors to stimulate proliferation of stem cells, progenitor cells, dendritic cells, and natural killer cells. Mutations of FLT3 have been detected in about 30% of patients with acute myelogenous leukemia and a small number of patients with acute lymphocytic leukemia or myelodysplastic syndrome. Patients with FLT3 mutations tend to have a poor prognosis. The mutations most often involve small tandem duplications of amino acids within the juxtamembrane domain of the receptor and result in constitutive tyrosine kinase activity. Expression of a mutant FLT3 receptor in murine marrow cells results in a lethal myeloproliferative syndrome and preliminary studies suggest that mutant FLT3 cooperates with other leukemia oncogenes to confer a more aggressive phenotype. Taken together, these results suggest that FLT3 is an attractive therapeutic target for kinase inhibitors or other approaches for patients with mutations of this gene.
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Affiliation(s)
- D Gary Gilliland
- Brigham and Women's Hospital, Howard Hughes Medical Institute, Boston, MA, USA.
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93
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Abstract
FLT3 is the most frequently mutated gene in cases of acute myelogenous leukemia (AML). About 30 to 35% of patients have either internal tandem duplications (ITDs) in the juxtamembrane domain or mutations in the activating loop of FLT3. FLT3 mutations occur in a broad spectrum of FAB subtypes in adult and pediatric AML and are particularly common in acute promyelocytic leukemia (APL). FLT3 mutations confer a poor prognosis in most retrospective studies. The consequence of either FLT3-ITD or activating loop mutations, which occur predominantly at position D835, is constitutive activation of the tyrosine kinase; FLT3 mutants confer factor-independent growth to Ba/F3 and 32D cells and activate similar transduction pathways as the native receptor in response to ligand, including the STAT, RAS/mitogen-activated protein kinase (MAPK), and phosphatidylinositol 3; kinase (PI3K)/AKT pathways. Injection of FLT3-ITD transformed cells, such as Ba/F3 or 32D, into syngeneic recipient mice results in a leukemia-like syndrome, and expression in primary murine bone marrow cells in a retroviral transduction assay results in a myeloproliferative disorder. Mutations that abrogate FLT3 kinase activity result in loss of transforming properties in these assays. Further, FLT3-selective inhibitors impair transformation of primary AML cells that harbor these mutations, and also inhibit FLT3 transformed hematopoietic cell lines, and leukemias induced by activated FLT3 mutants in murine models. Collectively, these data indicate that FLT3 may be a viable therapeutic target for treatment of AML.
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Affiliation(s)
- D Gary Gilliland
- Brigham and Women's Hospital, Howard Hughes Medical Institute, Harvard Medical School, Boston, Massachusetts, USA.
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94
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Affiliation(s)
- D Gary Gilliland
- Howard Hughes Medical Institute, Brigham and Women's Hospital, and Dana-Farber Cancer Institute, Harvard Medical School, Harvard Institutes of Medicine, 4 Blackfan Circle, Room 418, Boston, Massachusetts 02115, USA.
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95
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Milella M, Estrov Z, Kornblau SM, Carter BZ, Konopleva M, Tari A, Schober WD, Harris D, Leysath CE, Lopez-Berestein G, Huang Z, Andreeff M. Synergistic induction of apoptosis by simultaneous disruption of the Bcl-2 and MEK/MAPK pathways in acute myelogenous leukemia. Blood 2002; 99:3461-4. [PMID: 11964319 DOI: 10.1182/blood.v99.9.3461] [Citation(s) in RCA: 95] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Recent studies suggest that the Bcl-2 and mitogen-activated protein kinase (MAPK) pathways together confer an aggressive, apoptosis-resistant phenotype on acute myelogenous leukemia (AML) cells. In this study, we analyzed the effects of simultaneous inhibition of these 2 pathways. In AML cell lines with constitutively activated MAPK, MAPK kinase (MEK) blockade by PD184352 strikingly potentiated the apoptosis induced by the small-molecule Bcl-2 inhibitor HA14-1 or by Bcl-2 antisense oligonucleotides. Isobologram analysis confirmed the synergistic nature of this interaction. Moreover, MEK blockade overcame Bcl-2 overexpression-mediated resistance to the proapoptotic effects of HA14-1. Most importantly, simultaneous exposure to PD184352 significantly (P =.01) potentiated HA14-1-mediated inhibition of clonogenic growth in all primary AML samples tested. These findings show that the Bcl-2 and MAPK pathways are relevant molecular targets in AML and that their concurrent inhibition could be developed into a new therapeutic strategy for this disease.
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Affiliation(s)
- Michele Milella
- Department of Blood and Marrow Transplantation, Section of Molecular Hematology and Therapy, The University of Texas M. D. Anderson Cancer Center, Houston, TX 77030, USA
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96
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Jordan CT. Unique molecular and cellular features of acute myelogenous leukemia stem cells. Leukemia 2002; 16:559-62. [PMID: 11960332 DOI: 10.1038/sj.leu.2402446] [Citation(s) in RCA: 93] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2001] [Accepted: 12/10/2001] [Indexed: 12/22/2022]
Abstract
It is well known in the field of acute myelogenous leukemia (AML) that many different translocations and genetic aberrancies are found with the various forms of the disease. Indeed, specific translocations are often associated with disease subtypes that manifest themselves through the accumulation of immature myeloid cells at varying stages of differentiation. Moreover, the differentiation state of myeloid blast populations has been utilized as a means of categorizing different AML subtypes (French, American, British, or FAB classification system). Thus, the notion that AML is a family of related but distinct diseases is a common view. Interestingly, however, studies in recent years that have formalized the concept of a leukemic stem cell (LSC) have also begun to define shared developmental, cellular and molecular features amongst the malignant stem cells that give rise to different AML subtypes. Moreover, some of these conserved features appear to be unique to the leukemia stem/progenitor cell population, and are not found in normal hematopoietic stem cells (HSCs). This article will summarize data emerging from the study of LSCs and suggest how distinct molecular and cellular characteristics of the LSC population may provide new opportunities for AML therapy.
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Affiliation(s)
- C T Jordan
- Division of Hematology/Oncology, Markey Cancer Center, University of Kentucky Medical Center, Lexington, KY 40536, USA
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97
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Bibliography. Current awareness in hematological oncology. Hematol Oncol 2001; 19:159-66. [PMID: 11754392 DOI: 10.1002/hon.674] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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98
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Milella M, Kornblau SM, Estrov Z, Carter BZ, Lapillonne H, Harris D, Konopleva M, Zhao S, Estey E, Andreeff M. Therapeutic targeting of the MEK/MAPK signal transduction module in acute myeloid leukemia. J Clin Invest 2001; 108:851-9. [PMID: 11560954 PMCID: PMC200930 DOI: 10.1172/jci12807] [Citation(s) in RCA: 258] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The mitogen-activated protein kinase (MAPK) pathway regulates growth and survival of many cell types, and its constitutive activation has been implicated in the pathogenesis of a variety of malignancies. In this study we demonstrate that small-molecule MEK inhibitors (PD98059 and PD184352) profoundly impair cell growth and survival of acute myeloid leukemia (AML) cell lines and primary samples with constitutive MAPK activation. These agents abrogate the clonogenicity of leukemic cells but have minimal effects on normal hematopoietic progenitors. MEK blockade also results in sensitization to spontaneous and drug-induced apoptosis. At a molecular level, these effects correlate with modulation of the expression of cyclin-dependent kinase inhibitors (p27(Kip1) and p21(Waf1/CIP1)) and antiapoptotic proteins of the inhibitor of apoptosis proteins (IAP) and Bcl-2 families. Interruption of constitutive MEK/MAPK signaling therefore represents a promising therapeutic strategy in AML.
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Affiliation(s)
- M Milella
- Department of Blood and Marrow Transplantation, Section of Molecular Hematology and Therapy, The University of Texas, M.D. Anderson Cancer Center, Houston, Texas 77030, USA
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