1
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Blackmon A, Aldoss I, Ball BJ. FLT3 Inhibitors as Maintenance Therapy after Allogeneic Stem-Cell Transplantation. Blood Lymphat Cancer 2022; 12:137-147. [PMID: 36097605 PMCID: PMC9464008 DOI: 10.2147/blctt.s281252] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Accepted: 08/19/2022] [Indexed: 11/23/2022] Open
Abstract
Mutations in the FLT3 gene are associated with poor prognosis in patients with AML, even after consolidation with allogeneic hematopoietic cell transplantation (alloHCT) in first remission. Treatment failure in FLT3-mutated AML is largely driven by excessive risk of relapse compared to other genetic subtypes, including in patients post-alloHCT. As a result, there is substantial interest in studying posttransplant maintenance therapy in FLT3-mutated AML as an approach to optimize disease control and improve long-term outcomes. Clinical trials utilizing posttransplant FLT3 inhibitors, such as sorafenib and midostaurin, have shown feasibility, safety, and encouraging posttransplant outcomes, and there are ongoing studies using newer-generation tyrosine-kinase inhibitors as posttransplant maintenance therapy. Here, we review the toxicities and efficacy of FLT3 inhibitors as posttransplant maintenance, recommendations on the use of FLT3 inhibitors by international consensus guidelines, and highlight key remaining questions.
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Affiliation(s)
- Amanda Blackmon
- Department of Hematology and Hematopoietic Cell Transplantation, City of Hope National Medical Center, Duarte, CA, USA
| | - Ibrahim Aldoss
- Department of Hematology and Hematopoietic Cell Transplantation, City of Hope National Medical Center, Duarte, CA, USA
| | - Brian J Ball
- Department of Hematology and Hematopoietic Cell Transplantation, City of Hope National Medical Center, Duarte, CA, USA
- Correspondence: Brian J Ball, Division of Leukemia, Department of Hematology and HCT, City of Hope National Medical Center, 1500 E. Duarte Road, Duarte, CA, 91010, USA, Email
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2
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Dunphy K, Dowling P, Bazou D, O’Gorman P. Current Methods of Post-Translational Modification Analysis and Their Applications in Blood Cancers. Cancers (Basel) 2021; 13:1930. [PMID: 33923680 PMCID: PMC8072572 DOI: 10.3390/cancers13081930] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Revised: 04/04/2021] [Accepted: 04/14/2021] [Indexed: 12/12/2022] Open
Abstract
Post-translational modifications (PTMs) add a layer of complexity to the proteome through the addition of biochemical moieties to specific residues of proteins, altering their structure, function and/or localization. Mass spectrometry (MS)-based techniques are at the forefront of PTM analysis due to their ability to detect large numbers of modified proteins with a high level of sensitivity and specificity. The low stoichiometry of modified peptides means fractionation and enrichment techniques are often performed prior to MS to improve detection yields. Immuno-based techniques remain popular, with improvements in the quality of commercially available modification-specific antibodies facilitating the detection of modified proteins with high affinity. PTM-focused studies on blood cancers have provided information on altered cellular processes, including cell signaling, apoptosis and transcriptional regulation, that contribute to the malignant phenotype. Furthermore, the mechanism of action of many blood cancer therapies, such as kinase inhibitors, involves inhibiting or modulating protein modifications. Continued optimization of protocols and techniques for PTM analysis in blood cancer will undoubtedly lead to novel insights into mechanisms of malignant transformation, proliferation, and survival, in addition to the identification of novel biomarkers and therapeutic targets. This review discusses techniques used for PTM analysis and their applications in blood cancer research.
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Affiliation(s)
- Katie Dunphy
- Department of Biology, National University of Ireland, W23 F2K8 Maynooth, Ireland; (K.D.); (P.D.)
| | - Paul Dowling
- Department of Biology, National University of Ireland, W23 F2K8 Maynooth, Ireland; (K.D.); (P.D.)
| | - Despina Bazou
- Department of Haematology, Mater Misericordiae University Hospital, D07 WKW8 Dublin, Ireland;
| | - Peter O’Gorman
- Department of Haematology, Mater Misericordiae University Hospital, D07 WKW8 Dublin, Ireland;
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3
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Cueto FJ, Sancho D. The Flt3L/Flt3 Axis in Dendritic Cell Biology and Cancer Immunotherapy. Cancers (Basel) 2021; 13:1525. [PMID: 33810248 PMCID: PMC8037622 DOI: 10.3390/cancers13071525] [Citation(s) in RCA: 49] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2021] [Revised: 03/21/2021] [Accepted: 03/23/2021] [Indexed: 12/19/2022] Open
Abstract
Dendritic cells (DCs) prime anti-tumor T cell responses in tumor-draining lymph nodes and can restimulate T effector responses in the tumor site. Thus, in addition to unleashing T cell effector activity, current immunotherapies should be directed to boost DC function. Herein, we review the potential function of Flt3L as a tool for cancer immunotherapy. Flt3L is a growth factor that acts in Flt3-expressing multipotent progenitors and common lymphoid progenitors. Despite the broad expression of Flt3 in the hematopoietic progenitors, the main effect of the Flt3/Flt3L axis, revealed by the characterization of mice deficient in these genes, is the generation of conventional DCs (cDCs) and plasmacytoid DCs (pDCs). However, Flt3 signaling through PI3K and mTOR may also affect the function of mature DCs. We recapitulate the use of Flt3L in preclinical studies either as a single agent or in combination with other cancer therapies. We also analyze the use of Flt3L in clinical trials. The strong correlation between type 1 cDC (cDC1) infiltration of human cancers with overall survival in many cancer types suggests the potential use of Flt3L to boost expansion of this DC subset. However, this may need the combination of Flt3L with other immunomodulatory agents to boost cancer immunotherapy.
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Affiliation(s)
- Francisco J. Cueto
- Centro Nacional de Investigaciones Cardiovasculares (CNIC), 28029 Madrid, Spain
| | - David Sancho
- Centro Nacional de Investigaciones Cardiovasculares (CNIC), 28029 Madrid, Spain
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4
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Abstract
Aberrant FLT3 receptor signaling is common in acute myeloid leukemia (AML) and has important implications for the biology and clinical management of the disease. Patients with FLT3-mutated AML frequently present with critical illness, are more likely to relapse after treatment, and have worse clinical outcomes than their FLT3 wild type counterparts. The clinical management of FLT3-mutated AML has been transformed by the development of FLT3 inhibitors, which are now in use in the frontline and relapsed/refractory settings. However, many questions regarding the optimal approach to the treatment of these patients remain. In this paper, we will review the rationale for targeting the FLT3 receptor in AML, the impact of FLT3 mutation on patient prognosis, the current standard of care approaches to FLT3-mutated AML management, and the diverse array of FLT3 inhibitors in use and under investigation. We will also explore new opportunities and strategies for targeting the FLT3 receptor. These include targeting the receptor in patients with non-canonical FLT3 mutations or wild type FLT3, pairing FLT3 inhibitors with other novel therapies, using minimal residual disease (MRD) testing to guide the targeting of FLT3, and novel immunotherapeutic approaches.
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Affiliation(s)
- Alexander J Ambinder
- Department of Oncology, Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Mark Levis
- Department of Oncology, Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, Baltimore, MD, USA
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5
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Steiner N, Jöhrer K, Plewan S, Brunner-Véber A, Göbel G, Nachbaur D, Wolf D, Gunsilius E, Untergasser G. The FMS like Tyrosine Kinase 3 (FLT3) Is Overexpressed in a Subgroup of Multiple Myeloma Patients with Inferior Prognosis. Cancers (Basel) 2020; 12:cancers12092341. [PMID: 32825035 PMCID: PMC7565188 DOI: 10.3390/cancers12092341] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Revised: 08/05/2020] [Accepted: 08/16/2020] [Indexed: 11/16/2022] Open
Abstract
Therapy resistance remains a major challenge in the management of multiple myeloma (MM). We evaluated the expression of FLT3 tyrosine kinase receptor (FLT3, CD135) in myeloma cells as a possible clonal driver. FLT3 expression was analyzed in bone marrow biopsies of patients with monoclonal gammopathy of undetermined significance or smoldering myeloma (MGUS, SMM), newly diagnosed MM (NDMM), and relapsed/refractory MM (RRMM) by immunohistochemistry (IHC). FLT3 gene expression was analyzed by RNA sequencing (RNAseq) and real-time PCR (rt-PCR). Anti-myeloma activity of FLT3 inhibitors (midostaurin, gilteritinib) was tested in vitro on MM cell lines and primary MM cells by 3H-tymidine incorporation assays or flow cytometry. Semi-quantitative expression analysis applying a staining score (FLT3 expression IHC-score, FES, range 1-6) revealed that a high FES (>3) was associated with a significantly shorter progression-free survival (PFS) in NDMM and RRMM patients (p = 0.04). RNAseq and real-time PCR confirmed the expression of FLT3 in CD138-purified MM samples. The functional relevance of FLT3 expression was corroborated by demonstrating the in vitro anti-myeloma activity of FLT3 inhibitors on FLT3-positive MM cell lines and primary MM cells. FLT3 inhibitors might offer a new targeted therapy approach in a subgroup of MM patients displaying aberrant FLT3 signaling.
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Affiliation(s)
- Normann Steiner
- Department of Internal Medicine V (Hematology and Medical Oncology), Medical University of Innsbruck, Anichstraße 35, A-6020 Innsbruck, Austria; (S.P.); (D.N.); (D.W.); (E.G.); (G.U.)
- Correspondence: ; Tel.: +43-(0)-512-504-82926
| | - Karin Jöhrer
- Tyrolean Cancer Research Institute, Innrain 66, A-6020 Innsbruck, Austria;
| | - Selina Plewan
- Department of Internal Medicine V (Hematology and Medical Oncology), Medical University of Innsbruck, Anichstraße 35, A-6020 Innsbruck, Austria; (S.P.); (D.N.); (D.W.); (E.G.); (G.U.)
| | - Andrea Brunner-Véber
- Department of Pathology, Neuropathology and Molecular Pathology, Medical University of Innsbruck, Müllerstraße 44, A-6020 Innsbruck, Austria;
| | - Georg Göbel
- Department of Medical Statistics, Informatics and Health Economics, Medical University of Innsbruck, Schöpfstraße 41/1, A-6020 Innsbruck, Austria;
| | - David Nachbaur
- Department of Internal Medicine V (Hematology and Medical Oncology), Medical University of Innsbruck, Anichstraße 35, A-6020 Innsbruck, Austria; (S.P.); (D.N.); (D.W.); (E.G.); (G.U.)
| | - Dominik Wolf
- Department of Internal Medicine V (Hematology and Medical Oncology), Medical University of Innsbruck, Anichstraße 35, A-6020 Innsbruck, Austria; (S.P.); (D.N.); (D.W.); (E.G.); (G.U.)
| | - Eberhard Gunsilius
- Department of Internal Medicine V (Hematology and Medical Oncology), Medical University of Innsbruck, Anichstraße 35, A-6020 Innsbruck, Austria; (S.P.); (D.N.); (D.W.); (E.G.); (G.U.)
| | - Gerold Untergasser
- Department of Internal Medicine V (Hematology and Medical Oncology), Medical University of Innsbruck, Anichstraße 35, A-6020 Innsbruck, Austria; (S.P.); (D.N.); (D.W.); (E.G.); (G.U.)
- Tyrolean Cancer Research Institute, Innrain 66, A-6020 Innsbruck, Austria;
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6
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Li GX, Wang L, Yaghmour B, Ramsingh G, Yaghmour G. The role of FLT3 inhibitors as maintenance therapy following hematopoietic stem cell transplant. Leuk Res Rep 2018; 10:26-36. [PMID: 30112274 PMCID: PMC6092446 DOI: 10.1016/j.lrr.2018.06.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2018] [Revised: 06/25/2018] [Accepted: 06/29/2018] [Indexed: 02/06/2023] Open
Abstract
Activating mutations in FLT3 in acute myeloid leukemia (AML) portend a poor prognosis, and targeting FLT3 with a tyrosine kinase inhibitor has been an area of intense research recently. Most FLT3 mutated AML patients undergo hematopoietic stem cell transplantation (HSCT) as standard of care but a significant proportion of patients relapse. Although the use of FLT3 inhibitors in the pre-HSCT perspective is more clearly defined, its use in the post-HSCT scenario, when most relapses occur, remains unclear. In this review, we comprehensively present the data on the recent and ongoing studies evaluating the role of various FLT3 inhibitors in AML with a particular focus in the post-HSCT setting.
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Affiliation(s)
- Grace Xiuqing Li
- Jane Anne Nohl Division of Hematology and Center for the Study of Blood Diseases, University of Southern California, Keck School of Medicine of USC, USC Norris Comprehensive Cancer Center, Los Angeles, CA 90033, United States
| | - Lan Wang
- Department of Medicine, University of Southern California, Keck School of Medicine of USC, Los Angeles, CA 90033, United States
| | - Bassam Yaghmour
- Department of Pulmonary and Critical Care, University of Southern California, Keck School of Medicine of USC, Los Angeles, CA 90033, United States
| | - Giridharan Ramsingh
- Jane Anne Nohl Division of Hematology and Center for the Study of Blood Diseases, University of Southern California, Keck School of Medicine of USC, USC Norris Comprehensive Cancer Center, Los Angeles, CA 90033, United States
| | - George Yaghmour
- Jane Anne Nohl Division of Hematology and Center for the Study of Blood Diseases, University of Southern California, Keck School of Medicine of USC, USC Norris Comprehensive Cancer Center, Los Angeles, CA 90033, United States
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7
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Buetti-Dinh A, Friedman R. Computer simulations of the signalling network in FLT3 +-acute myeloid leukaemia - indications for an optimal dosage of inhibitors against FLT3 and CDK6. BMC Bioinformatics 2018; 19:155. [PMID: 29699481 PMCID: PMC5921566 DOI: 10.1186/s12859-018-2145-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Accepted: 04/03/2018] [Indexed: 12/31/2022] Open
Abstract
Background Mutations in the FMS-like tyrosine kinase 3 (FLT3) are associated with uncontrolled cellular functions that contribute to the development of acute myeloid leukaemia (AML). We performed computer simulations of the FLT3-dependent signalling network in order to study the pathways that are involved in AML development and resistance to targeted therapies. Results Analysis of the simulations revealed the presence of alternative pathways through phosphoinositide 3 kinase (PI3K) and SH2-containing sequence proteins (SHC), that could overcome inhibition of FLT3. Inhibition of cyclin dependent kinase 6 (CDK6), a related molecular target, was also tested in the simulation but was not found to yield sufficient benefits alone. Conclusions The PI3K pathway provided a basis for resistance to treatments. Alternative signalling pathways could not, however, restore cancer growth signals (proliferation and loss of apoptosis) to the same levels as prior to treatment, which may explain why FLT3 resistance mutations are the most common resistance mechanism. Finally, sensitivity analysis suggested the existence of optimal doses of FLT3 and CDK6 inhibitors in terms of efficacy and toxicity. Electronic supplementary material The online version of this article (10.1186/s12859-018-2145-y) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Antoine Buetti-Dinh
- Department of Chemistry and Biomedical Sciences, Linnæus University, Norra vägen 49, Kalmar, SE-391 82, Sweden.,Linnæus University Centre for Biomaterials Chemistry, Linnæus University, Norra vägen 49, Kalmar, SE-391 82, Sweden.,Centre for Ecology and Evolution in Microbial Model Systems, Linnæus University, Landgången 3, Kalmar, SE-391 82, Sweden.,Institute of Computational Science, Faculty of Informatics, Università della Svizzera Italiana, Via Giuseppe Buffi 13, Lugano, CH-6900, Switzerland.,Swiss Institute of Bioinformatics, Quartier Sorge - Batiment Genopode, Lausanne, CH-1015, Switzerland
| | - Ran Friedman
- Department of Chemistry and Biomedical Sciences, Linnæus University, Norra vägen 49, Kalmar, SE-391 82, Sweden. .,Linnæus University Centre for Biomaterials Chemistry, Linnæus University, Norra vägen 49, Kalmar, SE-391 82, Sweden.
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8
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Durai V, Bagadia P, Briseño CG, Theisen DJ, Iwata A, Davidson JT, Gargaro M, Fremont DH, Murphy TL, Murphy KM. Altered compensatory cytokine signaling underlies the discrepancy between Flt3-/- and Flt3l-/- mice. J Exp Med 2018; 215:1417-1435. [PMID: 29572360 PMCID: PMC5940266 DOI: 10.1084/jem.20171784] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Revised: 01/10/2018] [Accepted: 02/22/2018] [Indexed: 12/19/2022] Open
Abstract
The receptor Flt3 and its ligand Flt3L are both critical for dendritic cell (DC) development, but DC deficiency is more severe in Flt3l-/- mice than in Flt3-/- mice. This has led to speculation that Flt3L binds to another receptor that also supports DC development. However, we found that Flt3L administration does not generate DCs in Flt3-/- mice, arguing against a second receptor. Instead, Flt3-/- DC progenitors matured in response to macrophage colony-stimulating factor (M-CSF) or stem cell factor, and deletion of Csf1r in Flt3-/- mice further reduced DC development, indicating that these cytokines could compensate for Flt3. Surprisingly, Flt3-/- DC progenitors displayed enhanced M-CSF signaling, suggesting that loss of Flt3 increased responsiveness to other cytokines. In agreement, deletion of Flt3 in Flt3l-/- mice paradoxically rescued their severe DC deficiency. Thus, multiple cytokines can support DC development, and the discrepancy between Flt3-/- and Flt3l-/- mice results from the increased sensitivity of Flt3-/- progenitors to these cytokines.
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Affiliation(s)
- Vivek Durai
- Department of Pathology and Immunology, Washington University in St. Louis, School of Medicine, St. Louis, MO
| | - Prachi Bagadia
- Department of Pathology and Immunology, Washington University in St. Louis, School of Medicine, St. Louis, MO
| | - Carlos G Briseño
- Department of Pathology and Immunology, Washington University in St. Louis, School of Medicine, St. Louis, MO
| | - Derek J Theisen
- Department of Pathology and Immunology, Washington University in St. Louis, School of Medicine, St. Louis, MO
| | - Arifumi Iwata
- Department of Pathology and Immunology, Washington University in St. Louis, School of Medicine, St. Louis, MO
| | - Jesse T Davidson
- Department of Pathology and Immunology, Washington University in St. Louis, School of Medicine, St. Louis, MO
| | - Marco Gargaro
- Department of Pathology and Immunology, Washington University in St. Louis, School of Medicine, St. Louis, MO
| | - Daved H Fremont
- Department of Pathology and Immunology, Washington University in St. Louis, School of Medicine, St. Louis, MO
| | - Theresa L Murphy
- Department of Pathology and Immunology, Washington University in St. Louis, School of Medicine, St. Louis, MO
| | - Kenneth M Murphy
- Department of Pathology and Immunology, Washington University in St. Louis, School of Medicine, St. Louis, MO .,Howard Hughes Medical Institute, Washington University in St. Louis, School of Medicine, St. Louis, MO
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9
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Gallogly MM, Lazarus HM, Cooper BW. Midostaurin: a novel therapeutic agent for patients with FLT3-mutated acute myeloid leukemia and systemic mastocytosis. Ther Adv Hematol 2017; 8:245-261. [PMID: 29051803 DOI: 10.1177/2040620717721459] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2017] [Accepted: 06/28/2017] [Indexed: 12/12/2022] Open
Abstract
The development of FLT3-targeted inhibitors represents an important paradigm shift in the management of patients with highly aggressive fms-like tyrosine kinase 3-mutated (FLT3-mut) acute myeloid leukemia (AML). Midostaurin is an orally administered type III tyrosine kinase inhibitor which in addition to FLT3 inhibits c-kit, platelet-derived growth factor receptors, src, and vascular endothelial growth factor receptor. Midostaurin is the first FLT3 inhibitor that has been shown to significantly improve survival in younger patients with FLT3-mut AML when given in combination with standard cytotoxic chemotherapy based on the recently completed RATIFY study. Its role for maintenance therapy after allogeneic transplantation and use in combination with hypomethylating agents for older patients with FLT3-mut has not yet been defined. Midostaurin also has recently been shown to have significant activity in systemic mastocytosis and related disorders due to its inhibitory effect on c-kit bearing a D816V mutation. Activation of downstream pathways in both of these myeloid malignancies likely plays an important role in the development of resistance, and strategies to inhibit these downstream targets may be synergistic. Incorporating patient factors and tumor characteristics, such as FLT3 mutant to wild-type allele ratios and resistance mutations, likely will be important in the optimization of midostaurin and other FLT3 inhibitors in the treatment of myeloid neoplasms.
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Affiliation(s)
- Molly M Gallogly
- Department of Medicine, University Hospitals Cleveland Medical Center, Case Comprehensive Cancer Center, Case Western Reserve University, Cleveland, OH, USA
| | - Hillard M Lazarus
- Department of Medicine, University Hospitals Cleveland Medical Center, Case Comprehensive Cancer Center, Case Western Reserve University, Cleveland, OH, USA
| | - Brenda W Cooper
- Department of Medicine, University Hospitals Cleveland Medical Center, 11100 Euclid Avenue, Cleveland, OH 44106, USA
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10
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Tsapogas P, Mooney CJ, Brown G, Rolink A. The Cytokine Flt3-Ligand in Normal and Malignant Hematopoiesis. Int J Mol Sci 2017; 18:E1115. [PMID: 28538663 PMCID: PMC5485939 DOI: 10.3390/ijms18061115] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2017] [Revised: 05/18/2017] [Accepted: 05/19/2017] [Indexed: 12/22/2022] Open
Abstract
The cytokine Fms-like tyrosine kinase 3 ligand (FL) is an important regulator of hematopoiesis. Its receptor, Flt3, is expressed on myeloid, lymphoid and dendritic cell progenitors and is considered an important growth and differentiation factor for several hematopoietic lineages. Activating mutations of Flt3 are frequently found in acute myeloid leukemia (AML) patients and associated with a poor clinical prognosis. In the present review we provide an overview of our current knowledge on the role of FL in the generation of blood cell lineages. We examine recent studies on Flt3 expression by hematopoietic stem cells and its potential instructive action at early stages of hematopoiesis. In addition, we review current findings on the role of mutated FLT3 in leukemia and the development of FLT3 inhibitors for therapeutic use to treat AML. The importance of mouse models in elucidating the role of Flt3-ligand in normal and malignant hematopoiesis is discussed.
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Affiliation(s)
- Panagiotis Tsapogas
- Developmental and Molecular Immunology, Department of Biomedicine, University of Basel, Mattenstrasse 28, Basel 4058, Switzerland.
| | - Ciaran James Mooney
- Institute of Immunology and Immunotherapy, College of Medical and Dental Sciences, University of Birmingham, Edbgaston, Birmingham B15 2TT, UK.
| | - Geoffrey Brown
- Institute of Immunology and Immunotherapy, College of Medical and Dental Sciences, University of Birmingham, Edbgaston, Birmingham B15 2TT, UK.
- Institute of Clinical Sciences, College of Medical and Dental Sciences, University of Birmingham, Edbgaston, Birmingham B15 2TT, UK.
| | - Antonius Rolink
- Developmental and Molecular Immunology, Department of Biomedicine, University of Basel, Mattenstrasse 28, Basel 4058, Switzerland.
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11
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Beach TA, Johnston CJ, Groves AM, Williams JP, Finkelstein JN. Radiation induced pulmonary fibrosis as a model of progressive fibrosis: Contributions of DNA damage, inflammatory response and cellular senescence genes. Exp Lung Res 2017; 43:134-149. [PMID: 28534660 DOI: 10.1080/01902148.2017.1318975] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Purpose/Aim of Study: Studies of pulmonary fibrosis (PF) have resulted in DNA damage, inflammatory response, and cellular senescence being widely hypothesized to play a role in the progression of the disease. Utilizing these aforementioned terms, genomics databases were interrogated along with the term, "pulmonary fibrosis," to identify genes common among all 4 search terms. Findings were compared to data derived from a model of radiation-induced progressive pulmonary fibrosis (RIPF) to verify that these genes are similarly expressed, supporting the use of radiation as a model for diseases involving PF, such as human idiopathic pulmonary fibrosis (IPF). MATERIALS AND METHODS In an established model of RIPF, C57BL/6J mice were exposed to 12.5 Gy thorax irradiation and sacrificed at 24 hours, 1, 4, 12, and 32 weeks following exposure, and lung tissue was compared to age-matched controls by RNA sequencing. RESULTS Of 176 PF associated gene transcripts identified by database interrogation, 146 (>82%) were present in our experimental model, throughout the progression of RIPF. Analysis revealed that nearly 85% of PF gene transcripts were associated with at least 1 other search term. Furthermore, of 22 genes common to all four terms, 16 were present experimentally in RIPF. CONCLUSIONS This illustrates the validity of RIPF as a model of progressive PF/IPF based on the numbers of transcripts reported in both literature and observed experimentally. Well characterized genes and proteins are implicated in this model, supporting the hypotheses that DNA damage, inflammatory response and cellular senescence are associated with the pathogenesis of PF.
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Affiliation(s)
- Tyler A Beach
- a Department of Environmental Medicine , University of Rochester Medical Center , Rochester , New York , USA
| | - Carl J Johnston
- a Department of Environmental Medicine , University of Rochester Medical Center , Rochester , New York , USA.,b Department of Pediatrics and Neonatology , University of Rochester School of Medicine and Dentistry , Rochester , New York , USA
| | - Angela M Groves
- b Department of Pediatrics and Neonatology , University of Rochester School of Medicine and Dentistry , Rochester , New York , USA
| | - Jacqueline P Williams
- a Department of Environmental Medicine , University of Rochester Medical Center , Rochester , New York , USA
| | - Jacob N Finkelstein
- a Department of Environmental Medicine , University of Rochester Medical Center , Rochester , New York , USA.,b Department of Pediatrics and Neonatology , University of Rochester School of Medicine and Dentistry , Rochester , New York , USA
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12
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FYN expression potentiates FLT3-ITD induced STAT5 signaling in acute myeloid leukemia. Oncotarget 2017; 7:9964-74. [PMID: 26848862 PMCID: PMC4891096 DOI: 10.18632/oncotarget.7128] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2015] [Accepted: 01/19/2016] [Indexed: 01/31/2023] Open
Abstract
FYN is a non-receptor tyrosine kinase belonging to the SRC family of kinases, which are frequently over-expressed in human cancers, and play key roles in cancer biology. SRC has long been recognized as an important oncogene, but little attention has been given to its other family members. In this report, we have studied the role of FYN in FLT3 signaling in respect to acute myeloid leukemia (AML). We observed that FYN displays a strong association with wild-type FLT3 as well as oncogenic FLT3-ITD and is dependent on the kinase activity of FLT3 and the SH2 domain of FYN. We identified multiple FYN binding sites in FLT3, which partially overlapped with SRC binding sites. To understand the role of FYN in FLT3 signaling, we generated FYN overexpressing cells. We observed that expression of FYN resulted in slightly enhanced phosphorylation of AKT, ERK1/2 and p38 in response to ligand stimulation. Furthermore, FYN expression led to a slight increase in FLT3-ITD-dependent cell proliferation, but potent enhancement of STAT5 phosphorylation as well as colony formation. We also observed that FYN expression is deregulated in AML patient samples and that higher expression of FYN, in combination with FLT3-ITD mutation, resulted in enrichment of the STAT5 signaling pathway and correlated with poor prognosis in AML. Taken together our data suggest that FYN cooperates with oncogenic FLT3-ITD in cellular transformation by selective activation of the STAT5 pathway. Therefore, inhibition of FYN, in combination with FLT3 inhibition, will most likely be beneficial for this group of AML patients.
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13
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Abstract
FLT3-mutated acute myeloid leukemia (AML), despite not being recognized as a distinct entity in the World Health Organization (WHO) classification system, is readily recognized as a particular challenge by clinical specialists who treat acute leukemia. This is especially true with regards to the patients harboring the most common type of FLT3 mutation, the internal tandem duplication (FLT3-ITD) mutation. Here we present 4 patient cases from our institution and discuss how our management reflects what we have learned about this subtype of the disease. We also reflect on how we anticipate the management might change in the near future, with the emergence of clinically useful tyrosine kinase inhibitors.
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14
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AbdulSalam SF, Thowfeik FS, Merino EJ. Excessive Reactive Oxygen Species and Exotic DNA Lesions as an Exploitable Liability. Biochemistry 2016; 55:5341-52. [PMID: 27582430 DOI: 10.1021/acs.biochem.6b00703] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Although the terms "excessive reactive oxygen species (ROS)" and "oxidative stress" are widely used, the implications of oxidative stress are often misunderstood. ROS are not a single species but a variety of compounds, each with unique biochemical properties and abilities to react with biomolecules. ROS cause activation of growth signals through thiol oxidation and may lead to DNA damage at elevated levels. In this review, we first discuss a conceptual framework for the interplay of ROS and antioxidants. This review then describes ROS signaling using FLT3-mediated growth signaling as an example. We then focus on ROS-mediated DNA damage. High concentrations of ROS result in various DNA lesions, including 8-oxo-7,8-dihydro-guanine, oxazolone, DNA-protein cross-links, and hydantoins, that have unique biological impacts. Here we delve into the biochemistry of nine well-characterized DNA lesions. Within each lesion, the types of repair mechanisms, the mutations induced, and their effects on transcription and replication are discussed. Finally, this review will discuss biochemically inspired implications for cancer therapy. Several teams have put forward designs to harness the excessive ROS and the burdened DNA repair systems of tumor cells for treating cancer. We discuss inhibition of the antioxidant system, the targeting of DNA repair, and ROS-activated prodrugs.
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Affiliation(s)
- Safnas F AbdulSalam
- Department of Chemistry, University of Cincinnati , 404 Crosley Tower, Cincinnati, Ohio 45221-0172, United States
| | - Fathima Shazna Thowfeik
- Department of Chemistry, University of Cincinnati , 404 Crosley Tower, Cincinnati, Ohio 45221-0172, United States
| | - Edward J Merino
- Department of Chemistry, University of Cincinnati , 404 Crosley Tower, Cincinnati, Ohio 45221-0172, United States
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15
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Abstract
FLT3/ITD acute myeloid leukemia is a poor prognosis disease driven by a constitutively activated receptor tyrosine kinase, making it an obvious target for drug development. The development of clinically effective FLT3 inhibitors has been slow, in part because many are multi-targeted inhibitors that are not selective or specific for FLT3. Quizartinib is the first small molecule FLT3 tyrosine kinase inhibitor expressly developed as a FLT3 inhibitor. It is potent, selective and has ideal pharmacokinetics in comparison to other compounds previously tested. This article summarizes its advantages and limitations, and details the insights into the biology of the disease that have been uncovered through the laboratory and clinical use of quizartinib.
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16
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Flk2/Flt3 promotes both myeloid and lymphoid development by expanding non-self-renewing multipotent hematopoietic progenitor cells. Exp Hematol 2013; 42:218-229.e4. [PMID: 24333663 DOI: 10.1016/j.exphem.2013.11.013] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2013] [Revised: 10/22/2013] [Accepted: 11/22/2013] [Indexed: 12/21/2022]
Abstract
Defining differentiation pathways is central to understanding the pathogenesis of hematopoietic disorders, including leukemia. The function of the receptor tyrosine kinase Flk2 (Flt3) in promoting myeloid development remains poorly defined, despite being commonly mutated in acute myeloid leukemia. We investigated the effect of Flk2 deficiency on myelopoiesis, focusing on specification of progenitors between HSC and mature cells. We provide evidence that Flk2 is critical for proliferative expansion of multipotent progenitors that are common precursors for all lymphoid and myeloid lineages, including megakaryocyte/erythroid (MegE) cells. Flk2 deficiency impaired the generation of both lymphoid and myeloid progenitors by abrogating propagation of their common upstream precursor. At steady state, downstream compensatory mechanisms masked the effect of Flk2 deficiency on mature myeloid output, whereas transplantation of purified progenitors revealed impaired generation of all mature lineages. Flk2 deficiency did not affect lineage choice, thus dissociating the role of Flk2 in promoting cell expansion and regulating cell fate. Surprisingly, despite impairing myeloid development, Flk2 deficiency afforded protection against myeloablative insult. This survival advantage was attributed to reduced cell cycling and proliferation of progenitors in Flk2-deficient mice. Our data support the existence of a common Flk2(+) intermediate for all hematopoietic lineages and provide insight into how activating Flk2 mutations promote hematopoietic malignancy by non-Flk2-expressing myeloid cells.
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17
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Abstract
Blasts from approximately one-third of patients with acute myeloid leukemia (AML) harbor activating mutations in the FMS-like tyrosine kinase 3 (FLT3) receptor tyrosine kinase that confer a poor prognosis. The Mucin 1-C-terminal subunit (MUC1-C) oncoprotein is aberrantly expressed in AML blasts and stem cells; however, there is no known interaction between MUC1-C and FLT3. The present studies demonstrate that MUC1-C associates with wild-type and mutant FLT3 in AML cells. Targeting MUC1-C with the cell-penetrating peptide inhibitor GO-203 disrupts MUC1-C/FLT3 complexes and downregulates FLT3 activation. GO-203 treatment of AML cells was also associated with inhibition of the FLT3 downstream effectors AKT, extracellular signal-regulated kinase, and STAT5. The results further show that AML cells with FLT3-activating mutations and resistant to the FLT3 inhibitor midostaurin/PKC412 are sensitive to GO-203-induced growth arrest and death. Moreover, GO-203 increases sensitivity of mutant FLT3 AML cells to FLT3 inhibitor treatment. These results indicate that MUC1-C contributes to FLT3 activation in AML cells and that targeting MUC1-C inhibits the FLT3 signaling pathway. Our findings support the development of MUC1-C inhibitors alone and in combination with agents that target FLT3 for the treatment of wild-type and mutant FLT3 AML.
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18
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Kazi JU, Kabir NN, Rönnstrand L. Protein kinase C (PKC) as a drug target in chronic lymphocytic leukemia. Med Oncol 2013; 30:757. [PMID: 24174318 DOI: 10.1007/s12032-013-0757-7] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2013] [Accepted: 10/24/2013] [Indexed: 02/07/2023]
Abstract
Protein kinase C (PKC) belongs to a family of ten serine/threonine protein kinases encoded by nine genes. This family of proteins plays critical roles in signal transduction which results in cell proliferation, survival, differentiation and apoptosis. Due to differential subcellular localization and tissue distribution, each member displays distinct signaling characteristics. In this review, we have summarized the roles of PKC family members in chronic lymphocytic leukemia (CLL). CLL is a heterogeneous hematological disorder with survival ranging from months to decades. PKC isoforms are differentially expressed in CLL and play critical roles in CLL pathogenesis. Thus, isoform-specific PKC inhibitors may be an attractive option for CLL treatment.
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Affiliation(s)
- Julhash U Kazi
- Translational Cancer Research, Lund University, Medicon Village, Building 404:C3, 223 63, Lund, Sweden,
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19
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The Impact of FLT3 Mutations on the Development of Acute Myeloid Leukemias. LEUKEMIA RESEARCH AND TREATMENT 2013; 2013:275760. [PMID: 23936658 PMCID: PMC3725705 DOI: 10.1155/2013/275760] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 02/01/2013] [Revised: 04/30/2013] [Accepted: 05/14/2013] [Indexed: 11/17/2022]
Abstract
The development of the genetic studies on acute myeloid leukemias (AMLs) has led to the identification of some recurrent genetic abnormalities. Their discovery was of fundamental importance not only for a better understanding of the molecular pathogenesis of AMLs, but also for the identification of new therapeutic targets. In this context, it is essential to identify AML-associated “driver” mutations, which have a causative role in leukemogenesis. Evidences accumulated during the last years indicate that activating internal tandem duplication mutations in FLT3 (FLT3-ITD), detected in about 20% of AMLs, represents driver mutations and valid therapeutic targets in AMLs. Furthermore, the screening of FLT3-ITD mutations has also considerably helped to improve the identification of more accurate prognostic criteria and of the therapeutic selection of patients.
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20
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Cesano A, Putta S, Rosen DB, Cohen AC, Gayko U, Mathi K, Woronicz J, Hawtin RE, Cripe L, Sun Z, Tallman MS, Paietta E. Functional pathway analysis using SCNP of FLT3 receptor pathway deregulation in AML provides prognostic information independent from mutational status. PLoS One 2013; 8:e56714. [PMID: 23431389 PMCID: PMC3576376 DOI: 10.1371/journal.pone.0056714] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2012] [Accepted: 01/14/2013] [Indexed: 11/21/2022] Open
Abstract
FMS-like tyrosine kinase 3 receptor (FLT3) internal tandem duplication (ITD) mutations result in constitutive activation of this receptor and have been shown to increase the risk of relapse in patients with acute myeloid leukemia (AML); however, substantial heterogeneity in clinical outcomes still exists within both the ITD mutated and unmutated AML subgroups, suggesting alternative mechanisms of disease relapse not accounted by FLT3 mutational status. Single cell network profiling (SCNP) is a multiparametric flow cytometry based assay that simultaneously measures, in a quantitative fashion and at the single cell level, both extracellular surface marker levels and changes in intracellular signaling proteins in response to extracellular modulators. We previously reported an initial characterization of FLT3 ITD-mediated signaling using SCNP. Herein SCNP was applied sequentially to two separate cohorts of samples collected from elderly AML patients at diagnosis. In the first (training) study, AML samples carrying unmutated, wild-type FLT3 (FLT3 WT) displayed a wide range of induced signaling, with a fraction having signaling profiles comparable to FLT3 ITD AML samples. Conversely, the FLT3 ITD AML samples displayed more homogeneous induced signaling, with the exception of patients with low (<40%) mutational load, which had profiles comparable to FLT3 WT AML samples. This observation was then confirmed in an independent (verification) cohort. Data from the second cohort were also used to assess the association between SCNP data and disease-free survival (DFS) in the context of FLT3 and nucleophosmin (NPM1) mutational status among patients who achieved complete remission (CR) to induction chemotherapy. The combination of SCNP read outs together with FLT3 and NPM1 molecular status improved the DFS prediction accuracy of the latter. Taken together, these results emphasize the value of comprehensive functional assessment of biologically relevant signaling pathways in AML as a basis for the development of highly predictive tests for guidance of post-remission therapy.
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MESH Headings
- Aged
- Aged, 80 and over
- Apoptosis
- Cells, Cultured
- Disease-Free Survival
- Female
- Humans
- Induction Chemotherapy
- Kaplan-Meier Estimate
- Leukemia, Myeloid, Acute/drug therapy
- Leukemia, Myeloid, Acute/genetics
- Leukemia, Myeloid, Acute/metabolism
- Leukemia, Myeloid, Acute/mortality
- Male
- Middle Aged
- Multivariate Analysis
- Mutagenesis
- Mutation
- Nucleophosmin
- Principal Component Analysis
- Prognosis
- Signal Transduction
- Single-Cell Analysis
- fms-Like Tyrosine Kinase 3/genetics
- fms-Like Tyrosine Kinase 3/metabolism
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Affiliation(s)
- Alessandra Cesano
- Nodality, Inc., South San Francisco, California, United States of America
- * E-mail:
| | - Santosh Putta
- Nodality, Inc., South San Francisco, California, United States of America
| | - David B. Rosen
- Nodality, Inc., South San Francisco, California, United States of America
| | - Aileen C. Cohen
- Nodality, Inc., South San Francisco, California, United States of America
| | - Urte Gayko
- Nodality, Inc., South San Francisco, California, United States of America
| | - Kavita Mathi
- Nodality, Inc., South San Francisco, California, United States of America
| | - John Woronicz
- Nodality, Inc., South San Francisco, California, United States of America
| | - Rachael E. Hawtin
- Nodality, Inc., South San Francisco, California, United States of America
| | - Larry Cripe
- Eastern Cooperative Oncology Group (ECOG), Boston, Massachusetts, United States of America
- Indiana University Simon Cancer Center, Indianapolis, Indiana, United States of America
| | - Zhuoxin Sun
- Eastern Cooperative Oncology Group (ECOG), Boston, Massachusetts, United States of America
- Dana-Farber Cancer Institute, Boston, Massachusetts, United States of America
| | - Martin S. Tallman
- Eastern Cooperative Oncology Group (ECOG), Boston, Massachusetts, United States of America
- Memorial Sloan-Kettering Cancer Center, New York, New York, United States of America
| | - Elisabeth Paietta
- Eastern Cooperative Oncology Group (ECOG), Boston, Massachusetts, United States of America
- Montefiore Medical Center North Division, Bronx, New York, United States of America
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21
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Gow DJ, Garceau V, Kapetanovic R, Sester DP, Fici GJ, Shelly JA, Wilson TL, Hume DA. Cloning and expression of porcine Colony Stimulating Factor-1 (CSF-1) and Colony Stimulating Factor-1 Receptor (CSF-1R) and analysis of the species specificity of stimulation by CSF-1 and Interleukin 34. Cytokine 2012; 60:793-805. [PMID: 22974529 PMCID: PMC3500696 DOI: 10.1016/j.cyto.2012.08.008] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2012] [Revised: 07/02/2012] [Accepted: 08/07/2012] [Indexed: 01/09/2023]
Abstract
Macrophage Colony Stimulating Factor (CSF-1) controls the survival, differentiation and proliferation of cells of the mononuclear phagocyte system. A second ligand for the CSF-1R, Interleukin 34 (IL-34), has been described, but its physiological role is not yet known. The domestic pig provides an alternative to traditional rodent models for evaluating potential therapeutic applications of CSF-1R agonists and antagonists. To enable such studies, we cloned and expressed active pig CSF-1. To provide a bioassay, pig CSF-1R was expressed in the factor-dependent Ba/F3 cell line. On this transfected cell line, recombinant porcine CSF-1 and human CSF-1 had identical activity. Mouse CSF-1 does not interact with the human CSF-1 receptor but was active on pig. By contrast, porcine CSF-1 was active on mouse, human, cat and dog cells. IL-34 was previously shown to be species-specific, with mouse and human proteins demonstrating limited cross-species activity. The pig CSF-1R was equally responsive to both mouse and human IL-34. Based upon the published crystal structures of CSF-1/CSF-1R and IL34/CSF-1R complexes, we discuss the molecular basis for the species specificity.
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Affiliation(s)
- Deborah J. Gow
- The Roslin Institute, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Midlothian EH25 9RG, Scotland, UK
| | - Valerie Garceau
- The Roslin Institute, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Midlothian EH25 9RG, Scotland, UK
| | - Ronan Kapetanovic
- The Roslin Institute, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Midlothian EH25 9RG, Scotland, UK
| | - David P. Sester
- The Roslin Institute, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Midlothian EH25 9RG, Scotland, UK
| | - Greg J. Fici
- Pfizer Animal Health, 7000 Portage Road, Kalamazoo, MI 49001, United States
| | - John A. Shelly
- Pfizer Animal Health, 7000 Portage Road, Kalamazoo, MI 49001, United States
| | - Thomas L. Wilson
- Pfizer Animal Health, 7000 Portage Road, Kalamazoo, MI 49001, United States
| | - David A. Hume
- The Roslin Institute, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Midlothian EH25 9RG, Scotland, UK,Corresponding author. Tel.: +44 131 6519181.
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22
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Fathi AT, Chabner BA. FLT3 inhibition as therapy in acute myeloid leukemia: a record of trials and tribulations. Oncologist 2011; 16:1162-74. [PMID: 21765192 DOI: 10.1634/theoncologist.2011-0084] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Acute myeloid leukemia (AML) is a hematologic malignancy with a poor prognosis. Approximately one quarter of the patients with AML also carry an internal tandem duplication (ITD) mutation in the gene encoding FMS-like tyrosine kinase 3 (FLT3), which has a significantly deleterious impact on prognosis. The ITD mutation renders FLT3 constitutively active and leads to uncontrolled proliferation of the leukemic blast. Over the course of the last decade, a variety of compounds have been developed in preclinical and clinical studies as potent inhibitors of FLT3. Many of the earlier agents under investigation, such as lestaurtinib, midostaurin, and sunitinib, were initially developed as inhibitors of other tyrosine kinases and as targeted therapies in a variety of malignancies. These compounds have been demonstrated to have some efficacy in clinical trials of AML, mainly manifesting as transient decreases in circulating blasts correlating with effective in vivo suppression of the FLT3 target. Nevertheless, the cumbersome pharmacokinetics of some compounds and the suboptimal specificity and potency of others have limited their therapeutic efficacy. In the last few years, newer, more potent and specific agents have been under investigation, with the leading example being AC220. This agent has shown significant promise in early phases of clinical investigation, and is currently in more advanced clinical trials. Hope remains that FLT3 inhibition will be become an effective therapeutic adjunct to our current treatment approach to AML.
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Affiliation(s)
- Amir T Fathi
- Massachusetts General Hospital Cancer Center and Harvard Medical School, Boston, Massachusetts 02114, USA.
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23
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Abstract
Acute myeloid leukemia with a FLT3 internal tandem duplication (FLT3/ITD) mutation is an aggressive hematologic malignancy with a generally poor prognosis. It can be successfully treated into remission with intensive chemotherapy, but it routinely relapses. At relapse, the blasts tend to have higher mutant allelic ratios and, in vitro, are more addicted to the aberrant signaling from the FLT3/ITD oncoprotein. They remain highly responsive to FLT3 ligand, the levels of which rise several-fold during the course of chemotherapy. The question now arises as to whether these high levels of FLT3 ligand are actually promoting relapse, and, if so, how we can use this information to adjust our therapeutic approach and improve the cure rate for acute myeloid leukemia with FLT3/ITD.
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24
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Gu TL, Nardone J, Wang Y, Loriaux M, Villén J, Beausoleil S, Tucker M, Kornhauser J, Ren J, MacNeill J, Gygi SP, Druker BJ, Heinrich MC, Rush J, Polakiewicz RD. Survey of activated FLT3 signaling in leukemia. PLoS One 2011; 6:e19169. [PMID: 21552520 PMCID: PMC3084268 DOI: 10.1371/journal.pone.0019169] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2010] [Accepted: 03/21/2011] [Indexed: 12/17/2022] Open
Abstract
Activating mutations of FMS-like tyrosine kinase-3 (FLT3) are found in approximately 30% of patients with acute myeloid leukemia (AML). FLT3 is therefore an attractive drug target. However, the molecular mechanisms by which FLT3 mutations lead to cell transformation in AML remain unclear. To develop a better understanding of FLT3 signaling as well as its downstream effectors, we performed detailed phosphoproteomic analysis of FLT3 signaling in human leukemia cells. We identified over 1000 tyrosine phosphorylation sites from about 750 proteins in both AML (wild type and mutant FLT3) and B cell acute lymphoblastic leukemia (normal and amplification of FLT3) cell lines. Furthermore, using stable isotope labeling by amino acids in cell culture (SILAC), we were able to quantified over 400 phosphorylation sites (pTyr, pSer, and pThr) that were responsive to FLT3 inhibition in FLT3 driven human leukemia cell lines. We also extended this phosphoproteomic analysis on bone marrow from primary AML patient samples, and identify over 200 tyrosine and 800 serine/threonine phosphorylation sites in vivo. This study showed that oncogenic FLT3 regulates proteins involving diverse cellular processes and affects multiple signaling pathways in human leukemia that we previously appreciated, such as Fc epsilon RI-mediated signaling, BCR, and CD40 signaling pathways. It provides a valuable resource for investigation of oncogenic FLT3 signaling in human leukemia.
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Affiliation(s)
- Ting-lei Gu
- Cell Signaling Technology, Inc., Danvers, Massachusetts, United States of America
- * E-mail: (T-lG); (RDP)
| | - Julie Nardone
- Cell Signaling Technology, Inc., Danvers, Massachusetts, United States of America
| | - Yi Wang
- Cell Signaling Technology, Inc., Danvers, Massachusetts, United States of America
| | - Marc Loriaux
- Department of Pathology, Oregon Health & Science University, Portland, Oregon, United States of America
| | - Judit Villén
- Department of Cell Biology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Sean Beausoleil
- Cell Signaling Technology, Inc., Danvers, Massachusetts, United States of America
| | - Meghan Tucker
- Cell Signaling Technology, Inc., Danvers, Massachusetts, United States of America
| | - Jon Kornhauser
- Cell Signaling Technology, Inc., Danvers, Massachusetts, United States of America
| | - Jianmin Ren
- Cell Signaling Technology, Inc., Danvers, Massachusetts, United States of America
| | - Joan MacNeill
- Cell Signaling Technology, Inc., Danvers, Massachusetts, United States of America
| | - Steven P. Gygi
- Department of Cell Biology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Brian J. Druker
- Department of Hematology and Medical Oncology, Oregon Health & Science University, Portland, Oregon, United States of America
- Howard Hughes Medical Institute, Portland, Oregon, United States of America
| | - Michael C. Heinrich
- Department of Hematology and Medical Oncology, Oregon Health & Science University, Portland, Oregon, United States of America
- Portland VA Medical Center, Portland, Oregon, United States of America
| | - John Rush
- Cell Signaling Technology, Inc., Danvers, Massachusetts, United States of America
| | - Roberto D. Polakiewicz
- Cell Signaling Technology, Inc., Danvers, Massachusetts, United States of America
- * E-mail: (T-lG); (RDP)
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25
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Abstract
Somatic mutations of FLT3 involving internal tandem duplication (ITD) of the juxtamembrane domainor point mutations in the kinase domain (TKD) appear to activate FLT3 in a FLT3 ligand (FL) - independent manner. To determine whether or not FLT3 mutants respond to FL for their activation, a FL-deficient (FL−/−) murine embryo fibroblast cell line (MEF) was established. Expression of FLT3/ITD and FLT3/TKD mutations in FL−/− MEF cells resulted in low levels of constitutive phosphorylation of FLT3.However, a more than 4-fold increase of FLT3 autophosphorylation was induced by exogenous FL. Rescue of endogenous FL expression in FL−/− MEF cells expressing FLT3 mutants led to more than a 3-fold increase of FLT3 phosphorylation. FL addition led to further activation of the FLT3 receptors and enhanced survival and/or decreased apoptosis in leukemia-derived cell lines and primary leukemic cells expressing FLT3 mutations. Functional studies revealed that exogenous FL promoted the colony-forming and recloning abilities of FLT3 mutant transduced primary bone marrow cells derived from FL−/− mice. Endogenous FL contributes in vivo to functional signaling through FLT3 as noted by the decreased survival of FL+/+ITD+/+ mice compared with FL−/−ITD+/+ mice. These data suggest that FL leads to further activation of FLT3 mutants and is especially important in light of recent findings of elevated FL levels in AML patients in response to chemotherapy.
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26
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Takahashi S. Downstream molecular pathways of FLT3 in the pathogenesis of acute myeloid leukemia: biology and therapeutic implications. J Hematol Oncol 2011; 4:13. [PMID: 21453545 PMCID: PMC3076284 DOI: 10.1186/1756-8722-4-13] [Citation(s) in RCA: 150] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2011] [Accepted: 04/01/2011] [Indexed: 01/13/2023] Open
Abstract
FLT3 is a type III receptor tyrosine kinase. Mutations of FLT3 comprise one of the most frequently identified types of genetic alterations in acute myeloid leukemia. One-third of acute myeloid leukemia patients have mutations of this gene, and the majority of these mutations involve an internal tandem duplication in the juxtamembrane region of FLT3, leading to constitutive activation of downstream signaling pathways and aberrant cell growth. This review summarizes the current understanding of the effects of the downstream molecular signaling pathways after FLT3 activation, with a particular focus on the effects on transcription factors. Moreover, this review describes novel FLT3-targeted therapies, as well as efficient combination therapies for FLT3-mutated leukemia cells.
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Affiliation(s)
- Shinichiro Takahashi
- The Division of Molecular Hematology, Kitasato University Graduate School of Medical Sciences, 1-15-1 Kitasato, Minami-ku, Sagamihara 252-0373, Japan.
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27
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Chan PM. Differential signaling of Flt3 activating mutations in acute myeloid leukemia: a working model. Protein Cell 2011; 2:108-15. [PMID: 21359601 DOI: 10.1007/s13238-011-1020-7] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2011] [Accepted: 02/07/2011] [Indexed: 12/13/2022] Open
Abstract
Receptor tyrosine kinases couple a wide variety of extracellular cues to cellular responses. The class III subfamily comprises the platelet-derived growth factor receptor, c-Kit, Flt3 and c-Fms, all of which relay cell proliferation signals upon ligand binding. Accordingly, mutations in these proteins that confer ligand-independent activation are found in a subset of cancers. These mutations cluster in the juxtamembrane (JM) and catalytic tyrosine kinase domain (TKD) regions. In the case of acute myeloid leukemia (AML), the juxtamembrane (named ITD for internal tandem duplication) and TKD Flt3 mutants differ in their spectra of clinical outcomes. Although the mechanism of aberrant activation has been largely elucidated by biochemical and structural analyses of mutant kinases, the differences in disease presentation cannot be attributed to a change in substrate specificity or signaling strength of the catalytic domain. This review discusses the latest literature and presents a working model of differential Flt3 signaling based on mis-localized juxtamembrane autophosphorylation, to account for the disease variation. This will have bearing on therapeutic approaches in a complex disease such as AML, for which no efficacious drug yet exists.
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Affiliation(s)
- Perry M Chan
- Neuroscience Research Partnership, Biomedical Sciences Institute, affiliated with Institute of Molecular and Cell Biology, ASTAR, Singapore 138673, Singapore.
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28
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Rosen DB, Minden MD, Kornblau SM, Cohen A, Gayko U, Putta S, Woronicz J, Evensen E, Fantl WJ, Cesano A. Functional characterization of FLT3 receptor signaling deregulation in acute myeloid leukemia by single cell network profiling (SCNP). PLoS One 2010; 5:e13543. [PMID: 21048955 PMCID: PMC2965086 DOI: 10.1371/journal.pone.0013543] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2010] [Accepted: 09/19/2010] [Indexed: 01/08/2023] Open
Abstract
Background Molecular characterization of the FMS-like tyrosine kinase 3 receptor (FLT3) in cytogenetically normal acute myeloid leukemia (AML) has recently been incorporated into clinical guidelines based on correlations between FLT3 internal tandem duplications (FLT3-ITD) and decreased disease-free and overall survival. These mutations result in constitutive activation of FLT3, and FLT3 inhibitors are currently undergoing trials in AML patients selected on FLT3 molecular status. However, the transient and partial responses observed suggest that FLT3 mutational status alone does not provide complete information on FLT3 biological activity at the individual patient level. Examination of variation in cellular responsiveness to signaling modulation may be more informative. Methodology/Principal Findings Using single cell network profiling (SCNP), cells were treated with extracellular modulators and their functional responses were quantified by multiparametric flow cytometry. Intracellular signaling responses were compared between healthy bone marrow myeloblasts (BMMb) and AML leukemic blasts characterized as FLT3 wild type (FLT3-WT) or FLT3-ITD. Compared to healthy BMMb, FLT3-WT leukemic blasts demonstrated a wide range of signaling responses to FLT3 ligand (FLT3L), including elevated and sustained PI3K and Ras/Raf/Erk signaling. Distinct signaling and apoptosis profiles were observed in FLT3-WT and FLT3-ITD AML samples, with more uniform signaling observed in FLT3-ITD AML samples. Specifically, increased basal p-Stat5 levels, decreased FLT3L induced activation of the PI3K and Ras/Raf/Erk pathways, decreased IL-27 induced activation of the Jak/Stat pathway, and heightened apoptotic responses to agents inducing DNA damage were observed in FLT3-ITD AML samples. Preliminary analysis correlating these findings with clinical outcomes suggests that classification of patient samples based on signaling profiles may more accurately reflect FLT3 signaling deregulation and provide additional information for disease characterization and management. Conclusions/Significance These studies show the feasibility of SCNP to assess modulated intracellular signaling pathways and characterize the biology of individual AML samples in the context of genetic alterations.
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Affiliation(s)
- David B. Rosen
- Nodality, Inc., South San Francisco, California, United States of America
| | - Mark D. Minden
- Department of Medical Oncology/Hematology, The University of Toronto, Princess Margaret Hospital, Toronto, Ontario, Canada
| | - Steven M. Kornblau
- Department of Stem Cell Transplantation and Cellular Therapy, The University of Texas M. D. Anderson Cancer Center, Houston, Texas, United States of America
| | - Aileen Cohen
- Nodality, Inc., South San Francisco, California, United States of America
| | - Urte Gayko
- Nodality, Inc., South San Francisco, California, United States of America
| | - Santosh Putta
- Nodality, Inc., South San Francisco, California, United States of America
| | - John Woronicz
- Nodality, Inc., South San Francisco, California, United States of America
| | - Erik Evensen
- Nodality, Inc., South San Francisco, California, United States of America
| | - Wendy J. Fantl
- Nodality, Inc., South San Francisco, California, United States of America
| | - Alessandra Cesano
- Nodality, Inc., South San Francisco, California, United States of America
- * E-mail:
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29
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Pratz KW, Levis MJ. Bench to bedside targeting of FLT3 in acute leukemia. Curr Drug Targets 2010; 11:781-9. [PMID: 20370649 DOI: 10.2174/138945010791320782] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2009] [Accepted: 01/01/2010] [Indexed: 02/03/2023]
Abstract
FMS-Like-Tyrosine kinase-3 (FLT3) mutations are found in about 30% of cases of acute myeloid leukemia and confer an increased relapse rate and reduced overall survival. Targeting this tyrosine kinase by direction inhibition is the focus of both preclinical and clinical research in AML. Several molecules are in clinical development inhibit FLT3, but thus far clinical responses have been limited. Correlative studies from monotherapy trials have established that responses require sustained, effective FLT3 inhibition in vivo. Studies combining FLT3 inhibitors with chemotherapy have demonstrated increased remission rates to date but have yet to produce a survival advantage. Currently the only approved FLT3 inhibitor available for off-label use is sorafenib, which clearly has clinical activity but does not commonly lead to a complete response. Several FLT3 inhibitors are currently being tested as single agents and in combination with chemotherapy, and it seems likely that a clinically useful drug will eventually emerge.
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Affiliation(s)
- Keith W Pratz
- Department of Oncology, Division of Hematologic Malignancies, Sidney Kimmel Cancer Center at Johns Hopkins, 1650 Orleans Street, Baltimore, MD 21231, USA
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30
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Meshinchi S, Appelbaum FR. Structural and functional alterations of FLT3 in acute myeloid leukemia. Clin Cancer Res 2009; 15:4263-9. [PMID: 19549778 DOI: 10.1158/1078-0432.ccr-08-1123] [Citation(s) in RCA: 156] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Hematopoiesis is highly regulated through cytokine-induced stimulation of multiple signal transduction pathways in order to mediate appropriate differentiation and proliferation of specific progenitor populations. Ligand-induced stimulation of the FMS-like tyrosine kinase 3 (FLT3) leads to activation of multiple downstream effector pathways resulting in differentiation and proliferation of specific progenitor cell populations. Genomic alterations of the FLT3 gene, including FLT3 internal tandem duplication (FLT3/ITD) and FLT3 activation loop mutation (FLT3/ALM) lead to autonomous receptor activation, dysregulation of FLT3 signal transduction pathways, contribute to myeloid pathogenesis, and have been linked to response to therapy and clinical outcome. Exploring the mechanisms by which these FLT3 alterations lead to dysregulated proliferation should provide a better understanding of the molecular pathogenesis of acute myeloid leukemia (AML) and may provide insights into potential therapeutic interventions. FLT3 inhibitors are under evaluation for their efficacy in AML patients with FLT3 mutations.
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Affiliation(s)
- Soheil Meshinchi
- Clinical Research Division, Fred Hutchinson Cancer Research Center, Seattle, Washington, USA.
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31
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Mori S, Cortes J, Kantarjian H, Zhang W, Andreef M, Ravandi F. Potential role of sorafenib in the treatment of acute myeloid leukemia. Leuk Lymphoma 2009; 49:2246-55. [PMID: 19052971 DOI: 10.1080/10428190802510349] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The identification of aberrant cellular pathways and dysfunctional molecules important in neoplastic transformation has begun to provide us with a number of targets for drug development. It is likely that many of these agents will be incorporated into our existing treatment strategies that include cytotoxic agents. Sorafenib, a multi-kinase inhibitor has been approved in the United States for the treatment of renal cell carcinoma as well as hepatocellular cancer. Its potential role in hematological malignancies, particularly acute myeloid leukemia (AML) is under evaluation. Here we describe the biological pathways in AML that are the potential targets of sorafenib action and discuss the early clinical data with the agent in solid tumors and AML.
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Affiliation(s)
- Shahram Mori
- Department of Leukemia, University of Texas M. D. Anderson Cancer Center, Houston, TX 77030, USA
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32
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Pratz K, Levis M. Incorporating FLT3 inhibitors into acute myeloid leukemia treatment regimens. Leuk Lymphoma 2008; 49:852-63. [PMID: 18452067 DOI: 10.1080/10428190801895352] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
FMS-Like-Tyrosine kinase-3 (FLT3) mutations are found in about 30% of cases of acute myeloid leukemia and confer an increased relapse rate and reduced overall survival. Targeting of this tyrosine kinase by direction inhibition is the focus of both preclinical and clinical research in AML. Several molecules in clinical development inhibit FLT3 with varying degrees of specificity. Preclinical models suggest that these compounds enhance the cytotoxicity of conventional chemotherapeutics against FLT3 mutant leukemia cells. The pharmacodynamic interactions between FLT3 inhibitors and chemotherapy appear to be sequence dependent. When the FLT3 inhibitor is used prior to chemotherapy, antagonism is displayed, while if FLT3 inhibition is instituted after to exposure to chemotherapy, synergistic cytotoxicity is seen. The combination of FLT3 inhibitors with chemotherapy is also complicated by potential pharmacokinetic obstacles, such as plasma protein binding and p-glycoprotein interactions. Ongoing and future studies are aimed at incorporating FLT3 inhibitors into conventional induction and consolidation therapy specifically for patients with FLT3 mutant AML.
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Affiliation(s)
- Keith Pratz
- Division of Hematologic Malignancies, Department of Oncology, Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins, Baltimore, MD, USA
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33
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Knock-in of an internal tandem duplication mutation into murine FLT3 confers myeloproliferative disease in a mouse model. Blood 2008; 111:3849-58. [PMID: 18245664 DOI: 10.1182/blood-2007-08-109942] [Citation(s) in RCA: 107] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Constitutive activation of FMS-like tyrosine kinase 3 (FLT3) by internal tandem duplication (ITD) mutations is one of the most common molecular alterations known in acute myeloid leukemia (AML). To investigate the role FLT3/ITD mutations play in the development of leukemia, we generated a FLT3/ITD knock-in mouse model by inserting an ITD mutation into the juxtamembrane domain of murine Flt3. FLT3wt/ITD mice developed myeloproliferative disease, characterized by splenomegaly, leukocytosis, and myeloid hypercellularity, which progressed to mortality by 6 to 20 months. Bone marrow (BM) and spleen from FLT3wt/ITD mice had an increased fraction of granulocytes/monocytes and dendritic cells, and a decreased fraction of B-lymphocytes. No sign of acute leukemia was observed over the lifetime of these mice. BM from FLT3wt/ITD mice showed enhanced potential to generate myeloid colonies in vitro. BM from FLT3wt/ITD mice also produced more spleen colonies in the in vivo colony-forming unit (CFU)-spleen assay. In the long-term competitive repopulation assay, BM cells from FLT3wt/ITD mice outgrew the wild-type competitor cells and showed increased myeloid and reduced lymphoid expansion activity. In summary, our data indicate that expression of FLT3/ITD mutations alone is capable of conferring normal hematopoietic stem/progenitor cells (HSPCs) with enhanced myeloid expansion. It also appears to suppress B lymphoid maturation. Additional cooperative events appear to be required to progress to acute leukemia.
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34
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Barry EV, Clark JJ, Cools J, Roesel J, Gilliland DG. Uniform sensitivity of FLT3 activation loop mutants to the tyrosine kinase inhibitor midostaurin. Blood 2007; 110:4476-9. [PMID: 17827387 PMCID: PMC2234789 DOI: 10.1182/blood-2007-07-101238] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Small molecule inhibitors that target fms-like tyrosine kinase 3 (FLT3)-activating mutations have potential in the treatment of leukemias. However, certain mutations can simultaneously activate the tyrosine kinase, and confer resistance to small molecule inhibitors. We therefore tested the sensitivity of 8 FLT3 activation loop mutants to midostaurin. Each mutant conferred IL-3 factor-independent proliferation to Ba/F3 cells, and each resulted in the constitutive activation of FLT3 and its targets, signal transducer and activator of transcription 5 (STAT5) and extracellular stimuli-responsive kinase (ERK). For each mutant tested, midostaurin inhibited cell growth and phosphorylation of FLT3, STAT5, and ERK. In contrast, midostaruin did not inhibit Ba/F3 cells stably transduced with FLT3-internal tandem duplications containing a G697R mutation that confers resistance to midostaurin, demonstrating that midostaurin inhibition of FLT3 activation loop mutants was not due to off-target effects. We conclude that midostaurin is a potent inhibitor of a spectrum of FLT3 activation loop mutations, and that acute myeloid leukemia patients with such mutations are potential candidates for clinical trials involving midostaurin.
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Affiliation(s)
- Elly V Barry
- Dana-Farber Cancer Institute, Department of Pediatric Oncology, Boston, MA 02115, USA.
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35
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Omidvar N, Pearn L, Burnett AK, Darley RL. Ral is both necessary and sufficient for the inhibition of myeloid differentiation mediated by Ras. Mol Cell Biol 2006; 26:3966-75. [PMID: 16648489 PMCID: PMC1489015 DOI: 10.1128/mcb.26.10.3966-3975.2006] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Hyperactivation of Ras is one of the most common abnormalities in acute myeloid leukemia. In experimental models, Ras inhibits myeloid differentiation, which is characteristic of leukemia; however, the mechanism through which it disrupts hematopoiesis is poorly understood. In multipotent FDCP-mix cells, Ras inhibits terminal neutrophil differentiation, thereby indefinitely extending their proliferative potential. Ras also strongly promotes the sensitivity of these cells to granulocyte-macrophage colony-stimulating factor (GM-CSF). Using this model, we have dissected the signaling elements downstream of Ras to determine their relative contribution to the dysregulation of hematopoiesis. Cells expressing Ras mutants selectively activating Raf (Ras*T35S) or phosphatidylinositol 3-kinase (Ras*Y40C) did not significantly affect differentiation or proliferative capacity, whereas Ras*E37G (which selectively activates RalGEFs) perpetuated proliferation and blocked neutrophil development in a manner similar to that of Ras. Correspondingly, expression of constitutively active versions of these effectors confirmed the overriding importance of Ral guanine nucleotide exchange factors. Cells expressing Ras demonstrated hyperactivation of Ral, which itself was able to exactly mimic the phenotype of Ras, including hypersensitivity to GM-CSF. Conversely, dominant negative Ral promoted spontaneous neutrophil development. Ral, in turn, appears to influence differentiation through multiple effectors. These data show, for the first time, the importance of Ral in regulating differentiation and self-renewal in hematopoietic cells.
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Affiliation(s)
- Nader Omidvar
- Department of Haematology, School of Medicine, Cardiff School of Biosciences, Cardiff University, Museum Avenue, Cardiff, United Kingdom.
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36
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Whartenby KA, Calabresi PA, McCadden E, Nguyen B, Kardian D, Wang T, Mosse C, Pardoll DM, Small D. Inhibition of FLT3 signaling targets DCs to ameliorate autoimmune disease. Proc Natl Acad Sci U S A 2005; 102:16741-6. [PMID: 16272221 PMCID: PMC1283812 DOI: 10.1073/pnas.0506088102] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Autoimmune diseases often result from inappropriate or unregulated activation of autoreactive T cells. Traditional approaches to treatment of autoimmune diseases through immunosuppression have focused on direct inhibition of T cells. In the present study, we examined the targeted inhibition of antigen-presenting cells as a means to downregulate immune responses and treat autoimmune disease. Dendritic cells (DCs) are the central antigen-presenting cells for the initiation of T cell responses, including autoreactive ones. A large portion of DCs are derived from hematopoietic progenitors that express FLT3 receptor (CD135), and stimulation of the receptor via FLT3 ligand either in vivo or in vitro is known to drive expansion and differentiation of these progenitors toward a DC phenotype. We hypothesized that inhibition of FLT3 signaling would thus produce an inhibition of DC-induced stimulation of T cells, thereby inhibiting autoimmune responses. To this end, we used small-molecule tyrosine kinase inhibitors targeted against FLT3 and examined the effects on DCs and their role in the promulgation of autoimmune disease. Results of our studies show that inhibition of FLT3 signaling induces apoptosis in both mouse and human DCs, and thus is a potential target for immune suppression. Furthermore, targeted inhibition of FLT3 significantly improved the course of established disease in a model for multiple sclerosis, experimental autoimmune encephalomyelitis, suggesting a potential avenue for treating autoimmune disease.
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Affiliation(s)
- Katharine A Whartenby
- Department of Oncology, Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins, Baltimore, MD 21231, USA.
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37
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Levis M, Murphy KM, Pham R, Kim KT, Stine A, Li L, McNiece I, Smith BD, Small D. Internal tandem duplications of the FLT3 gene are present in leukemia stem cells. Blood 2005; 106:673-80. [PMID: 15797998 PMCID: PMC1895185 DOI: 10.1182/blood-2004-05-1902] [Citation(s) in RCA: 102] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Internal tandem duplication mutations of the FLT3 gene (FLT3/ITD mutations) are the most frequent molecular abnormality in acute myeloid leukemia (AML) and are associated with a poor overall survival. While the normal FLT3 receptor is expressed in early hematopoietic progenitor cells, it has not been determined whether FLT3 mutations are present in the leukemic stem cells. In this study, we sorted primary AML samples into stem cell-enriched CD34+/CD38- fractions and then analyzed the sorted and unsorted cells for the FLT3 mutant-wild-type ratio. In each case, the FLT3 mutant-wild-type ratio was not changed by selection of CD34+/CD38- cells, implying that the mutations are present in the leukemic stem cells. We used the stem cell-enriched fraction to engraft nonobese diabetic-severe combined immunodeficient (NOD-SCID) mice and then confirmed that the FLT3/ITD mutation was present in the resultant engrafted marrow. As a final test of the importance of FLT3/ITD signaling in this engraftment model, we used a small molecule FLT3 inhibitor, CEP-701, to inhibit engraftment of FLT3/ITD stem cells. Taken together, these experiments establish that the FLT3/ITD mutations are present in leukemia stem cells, and that FLT3 inhibitors may have activity against these cells.
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MESH Headings
- ADP-ribosyl Cyclase/metabolism
- ADP-ribosyl Cyclase 1
- Adult
- Aged
- Animals
- Antigens, CD/metabolism
- Antigens, CD34/metabolism
- Base Sequence
- Carbazoles/pharmacology
- Cell Separation
- DNA, Neoplasm/genetics
- Enzyme Inhibitors/pharmacology
- Female
- Furans
- Gene Duplication
- Humans
- Indoles/pharmacology
- Leukemia, Myeloid, Acute/enzymology
- Leukemia, Myeloid, Acute/genetics
- Leukemia, Myeloid, Acute/immunology
- Leukemia, Myeloid, Acute/pathology
- Membrane Glycoproteins
- Mice
- Mice, Inbred NOD
- Mice, SCID
- Middle Aged
- Neoplasm Transplantation
- Neoplastic Stem Cells/enzymology
- Neoplastic Stem Cells/immunology
- Neoplastic Stem Cells/pathology
- Neoplastic Stem Cells/transplantation
- Proto-Oncogene Proteins/antagonists & inhibitors
- Proto-Oncogene Proteins/genetics
- Receptor Protein-Tyrosine Kinases/antagonists & inhibitors
- Receptor Protein-Tyrosine Kinases/genetics
- Tandem Repeat Sequences
- Transplantation, Heterologous
- fms-Like Tyrosine Kinase 3
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38
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Godambe SA, Knapp KM, Meals EA, English BK. Role of vav1 in the lipopolysaccharide-mediated upregulation of inducible nitric oxide synthase production and nuclear factor for interleukin-6 expression activity in murine macrophages. CLINICAL AND DIAGNOSTIC LABORATORY IMMUNOLOGY 2005; 11:525-31. [PMID: 15138177 PMCID: PMC404562 DOI: 10.1128/cdli.11.3.525-531.2004] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
vav1 has been shown to play a key role in lymphocyte development and activation, but its potential importance in macrophage activation has received little attention. We have previously reported that exposure of macrophages to bacterial lipopolysaccharide (LPS) leads to increased activity of hck and other src-related tyrosine kinases and to the prompt phosphorylation of vav1 on tyrosine. In this study, we tested the role of vav1 in macrophage responses to LPS, focusing on the upregulation of nuclear factor for interleukin-6 expression (NF-IL-6) activity and inducible nitric oxide synthase (iNOS) protein accumulation in RAW-TT10 murine macrophages. We established a series of stable cell lines expressing three mutant forms of vav1 in a tetracycline-regulatable fashion: (i) a form producing a truncated protein, vavC; (ii) a form containing a point mutation in the regulatory tyrosine residue, vavYF174; and (iii) a form with an in-frame deletion of 6 amino acids required for the guanidine nucleotide exchange factor (GEF) activity of vav1 for rac family GTPases, vavGEFmt. Expression of the truncated mutant (but not the other two mutants) has been reported to interfere with T-cell activation. In contrast, we now demonstrate that expression of any of the three mutant forms of vav1 in RAW-TT10 cells consistently inhibited LPS-mediated increases in iNOS protein accumulation and NF-IL-6 activity. These data provide direct evidence for a role for vav1 in LPS-mediated macrophage activation and iNOS production and suggest that vav1 functions in part via activation of NF-IL-6. Furthermore, these findings indicate that the GEF activity of vav1 is required for its ability to mediate macrophage activation by LPS.
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Affiliation(s)
- Sandip A Godambe
- Department of Pediatrics, Children's Foundation Research Center, Le Bonheur Children's Medical Center, 50 N. Dunlap, Memphis, TN 38103, USA
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39
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Colucci F, Rosmaraki E, Bregenholt S, Samson SI, Di Bartolo V, Turner M, Vanes L, Tybulewicz V, Di Santo JP. Functional dichotomy in natural killer cell signaling: Vav1-dependent and -independent mechanisms. J Exp Med 2001; 193:1413-24. [PMID: 11413196 PMCID: PMC2193296 DOI: 10.1084/jem.193.12.1413] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The product of the protooncogene Vav1 participates in multiple signaling pathways and is a critical regulator of antigen-receptor signaling in B and T lymphocytes, but its role during in vivo natural killer (NK) cell differentiation is not known. Here we have studied NK cell development in Vav1-/- mice and found that, in contrast to T and NK-T cells, the absolute numbers of phenotypically mature NK cells were not reduced. Vav1-/- mice produced normal amounts of interferon (IFN)-gamma in response to Listeria monocytogenes and controlled early infection but showed reduced tumor clearance in vivo. In vitro stimulation of surface receptors in Vav1-/- NK cells resulted in normal IFN-gamma production but reduced tumor cell lysis. Vav1 was found to control activation of extracellular signal-regulated kinases and exocytosis of cytotoxic granules. In contrast, conjugate formation appeared to be only mildly affected, and calcium mobilization was normal in Vav1-/- NK cells. These results highlight fundamental differences between proximal signaling events in T and NK cells and suggest a functional dichotomy for Vav1 in NK cells: a role in cytotoxicity but not for IFN-gamma production.
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Affiliation(s)
- F Colucci
- Laboratory for Cytokines and Lymphoid Development, Pasteur Institute, 75015 Paris, France.
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40
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Zhang S, Fukuda S, Lee Y, Hangoc G, Cooper S, Spolski R, Leonard WJ, Broxmeyer HE. Essential role of signal transducer and activator of transcription (Stat)5a but not Stat5b for Flt3-dependent signaling. J Exp Med 2000; 192:719-28. [PMID: 10974037 PMCID: PMC2193267 DOI: 10.1084/jem.192.5.719] [Citation(s) in RCA: 166] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2000] [Accepted: 07/17/2000] [Indexed: 11/17/2022] Open
Abstract
The receptor tyrosine kinase Flt3 plays an important role in proliferation and survival of hematopoietic stem and progenitor cells. Although some post-receptor signaling events of Flt3 have been characterized, the involvement of the Janus kinase/signal transducer and activator of transcription (Jak/Stat) pathway in Flt3 signaling has not been thoroughly evaluated. To this aim, we examined whether Flt3 activates the Jak/Stat pathway in Baf3/Flt3 cells, a line stably expressing human Flt3 receptor. Stat5a, but not Stats 1-4, 5b, or 6, was potently activated by Flt3 ligand (FL) stimulation. Interestingly, FL did not activate any Jaks. Activation of Stat5a required the kinase activity of Flt3. A selective role for Stat5a in the proliferative response of primary hematopoietic progenitor cells to FL was documented, as FL did not act on progenitors from marrows of Stat5a(-/-) mice, but did stimulate/costimulate proliferation of these cells from Stat5a(+/+), Stat5b(-/-), and Stat5b(+/+) mice. Thus, Stat5a is essential for at least certain effects of FL. Moreover, our data confirm that Stat5a and Stat5b are not redundant, but rather are at least partially distinctive in their function.
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Affiliation(s)
- Shuli Zhang
- Department of Microbiology/Immunology, Indiana University School of Medicine, Indianapolis, Indiana 46202
- Walther Oncology Center, Indiana University School of Medicine, Indianapolis, Indiana 46202
- Walther Cancer Institute, Indianapolis, Indiana 46206
| | - Seiji Fukuda
- Department of Microbiology/Immunology, Indiana University School of Medicine, Indianapolis, Indiana 46202
- Walther Oncology Center, Indiana University School of Medicine, Indianapolis, Indiana 46202
- Walther Cancer Institute, Indianapolis, Indiana 46206
| | - Younghee Lee
- Department of Microbiology/Immunology, Indiana University School of Medicine, Indianapolis, Indiana 46202
- Walther Oncology Center, Indiana University School of Medicine, Indianapolis, Indiana 46202
- Walther Cancer Institute, Indianapolis, Indiana 46206
| | - Giao Hangoc
- Department of Microbiology/Immunology, Indiana University School of Medicine, Indianapolis, Indiana 46202
- Walther Oncology Center, Indiana University School of Medicine, Indianapolis, Indiana 46202
- Walther Cancer Institute, Indianapolis, Indiana 46206
| | - Scott Cooper
- Department of Microbiology/Immunology, Indiana University School of Medicine, Indianapolis, Indiana 46202
- Walther Oncology Center, Indiana University School of Medicine, Indianapolis, Indiana 46202
- Walther Cancer Institute, Indianapolis, Indiana 46206
| | - Rosanne Spolski
- Laboratory of Molecular Immunology, National Heart, Lung, and Blood Institute, Bethesda, Maryland 20892
| | - Warren J. Leonard
- Laboratory of Molecular Immunology, National Heart, Lung, and Blood Institute, Bethesda, Maryland 20892
| | - Hal E. Broxmeyer
- Department of Microbiology/Immunology, Indiana University School of Medicine, Indianapolis, Indiana 46202
- Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana 46202
- Walther Oncology Center, Indiana University School of Medicine, Indianapolis, Indiana 46202
- Walther Cancer Institute, Indianapolis, Indiana 46206
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41
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Affiliation(s)
- X R Bustelo
- Department of Pathology, State University of New York at Stony Brook, Stony Brook, New York 11794, USA.
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42
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Hayakawa F, Towatari M, Kiyoi H, Tanimoto M, Kitamura T, Saito H, Naoe T. Tandem-duplicated Flt3 constitutively activates STAT5 and MAP kinase and introduces autonomous cell growth in IL-3-dependent cell lines. Oncogene 2000; 19:624-31. [PMID: 10698507 DOI: 10.1038/sj.onc.1203354] [Citation(s) in RCA: 430] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
We have recently identified an internal tandem duplication of the human Flt3 gene in approximately 20% of acute myeloid leukemia (AML) cases. In the present study, the wild-type and the mutant Flt3 genes were transfected into two IL-3-dependent cell lines, 32D and BA/F3 cells. Mutant Flt3-transfected cells exhibited autonomous growth while wild-type Flt3-transfected cells with the continuous stimulation of Flt3 ligand exhibited a minimal proliferation. Cells expressing mutant Flt3 showed constitutive activation of STAT5 and MAP kinase. In contrast, Flt3 ligand stimulation caused rapid activation of MAP kinase but not STAT5 in cells expressing wild-type Flt3. Finally, we found constitutive activation of MAP kinase and STAT5 in all clinical samples of AML patients with mutant Flt3. Our study shows the significance of internal tandem duplication of Flt3 receptors for leukemia cell expansion.
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Affiliation(s)
- F Hayakawa
- First Department of Internal Medicine, Nagoya University School of Medicine, Japan
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43
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Blau CA, Peterson KR, Drachman JG, Spencer DM. A proliferation switch for genetically modified cells. Proc Natl Acad Sci U S A 1997; 94:3076-81. [PMID: 9096348 PMCID: PMC20324 DOI: 10.1073/pnas.94.7.3076] [Citation(s) in RCA: 82] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/1996] [Accepted: 01/13/1997] [Indexed: 02/04/2023] Open
Abstract
Receptor dimerization is the key signaling event for many cytokines, including erythropoietin. A system has been recently developed that permits intracellular protein dimerization to be reversibly activated in response to a lipid-soluble dimeric form of the drug FK506, called FK1012. FK1012 is used as a pharmacological mediator of dimerization to bring together FK506 binding domains, taken from the endogenous protein FKBP12. In experiments reported herein, FK1012-induced dimerization of a fusion protein containing the intracellular portion of the erythropoietin receptor allowed cells normally dependent on interleukin 3 to proliferate in its absence. FK506 competitively reversed the proliferative effect of FK1012 but had no influence on the proliferative effect of interleukin 3. Signaling pathways activated by FK1012 mimicked those activated by erythropoietin, because both JAK2 and STAT5 were phosphorylated in response to FK1012. This approach may provide a means to specifically and reversibly stimulate the proliferation of genetically modified cell populations in vitro or in vivo.
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Affiliation(s)
- C A Blau
- Division of Hematology, University of Washington, Seattle 98195, USA
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44
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Romero F, Dargemont C, Pozo F, Reeves WH, Camonis J, Gisselbrecht S, Fischer S. p95vav associates with the nuclear protein Ku-70. Mol Cell Biol 1996; 16:37-44. [PMID: 8524317 PMCID: PMC230976 DOI: 10.1128/mcb.16.1.37] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
The proto-oncogene vav is expressed solely in hematopoietic cells and plays an important role in cell signaling, although little is known about the proteins involved in these pathways. To gain further information, the Src homology 2 (SH2) and 3 (SH3) domains of Vav were used to screen a lymphoid cell cDNA library by the yeast two-hybrid system. Among the positive clones, we detected a nuclear protein, Ku-70, which is the DNA-binding element of the DNA-dependent protein kinase. In Jurkat and UT7 cells, Vav is partially localized in the nuclei, as judged from immunofluorescence and confocal microscopy studies. By using glutathione S-transferase fusion proteins derived from Ku-70 and coimmunoprecipitation experiments with lysates prepared from human thymocytes and Jurkat and UT7 cells, we show that Vav associates with Ku-70. The interaction of Vav with Ku-70 requires only the 150-residue carboxy-terminal portion of Ku-70, which binds to the 25 carboxy-terminal residues of the carboxy SH3 domain of Vav. A proline-to-leucine mutation in the carboxy SH3 of Vav that blocks interaction with proline-rich sequences does not modify the binding of Ku-70, which lacks this motif. Therefore, the interaction of Vav with Ku-70 may be a novel form of protein-protein interaction. The potential role of Vav/Ku-70 complexes is discussed.
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Affiliation(s)
- F Romero
- Institut Cochin de Génétique Moléculaire, U363 Institut National de la Santé et de la Recherche Médicale (INSERM), Hôpital Cochin, Paris, France
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Bustelo XR, Suen KL, Michael WM, Dreyfuss G, Barbacid M. Association of the vav proto-oncogene product with poly(rC)-specific RNA-binding proteins. Mol Cell Biol 1995; 15:1324-32. [PMID: 7862126 PMCID: PMC230356 DOI: 10.1128/mcb.15.3.1324] [Citation(s) in RCA: 74] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
We have used the yeast two-hybrid system to isolate proteins that interact with the carboxy-terminal SH3-SH2-SH3 region of Vav. One of the clones encoded heterogeneous nuclear ribonucleoprotein K (hnRNP K), a poly(rC)-specific RNA-binding protein. The interaction between Vav and hnRNP K involves the binding of the most carboxy-terminal SH3 domain of Vav to two proline-rich sequences present in the central region of hnRNP K. Overexpression of Vav in mouse fibroblasts leads to the formation of a stable complex with the endogenous hnRNP K and to the preferential redistribution of this protein to the cytoplasmic fraction. More importantly, Vav and hnRNP K proteins also interact in hematopoietic cells. In addition, Vav associates in vitro with a second 45-kDa poly(rC)-specific RNA-binding protein via its SH3-SH2-SH3 region. These results suggest that Vav plays a role in the regulation of the late steps of RNA biogenesis by modulating the function of poly(rC)-specific ribonucleoproteins.
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Affiliation(s)
- X R Bustelo
- Department of Molecular Biology, Bristol-Myers Squibb Pharmaceutical Research Institute, Princeton, New Jersey 08543-4000
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Zmuidzinas A, Fischer KD, Lira SA, Forrester L, Bryant S, Bernstein A, Barbacid M. The vav proto-oncogene is required early in embryogenesis but not for hematopoietic development in vitro. EMBO J 1995; 14:1-11. [PMID: 7828581 PMCID: PMC398046 DOI: 10.1002/j.1460-2075.1995.tb06969.x] [Citation(s) in RCA: 75] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Previous studies have suggested that the vav protooncogene plays an important role in hematopoiesis. To study this further, we have ablated the vav protooncogene by homologous recombination in embryonic stem (ES) cells. Homozygous vav (-/-) ES clones differentiate normally in culture and generate cells of erythroid, myeloid and mast cell lineages. Mice heterozygous for the targeted vav allele do not display any obvious abnormalities. However, homozygous embryos die very early during development. Crosses of vav (+/-) heterozygous mice yield apparently normal vav (-/-) E3.5 embryos but not post-implantation embryos (> or = E7.5). Furthermore, homozygous vav (-/-) blastocysts do not hatch in vitro. These results indicate that vav is essential for an early developmental step(s) that precedes the onset of hematopoiesis. Consistent with the phenotypic analysis of vav (-/-) embryos, we have identified Vav immunoreactivity in the extra-embryonic trophoblastic cell layer but not in the inner embryonic cell mass of E3.5 preimplantation embryos or in the egg cylinder of E6.5 and E7.5 post-implantation embryos. These results suggest that the vav gene is essential for normal trophoblast development and for implantation of the developing embryo.
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Affiliation(s)
- A Zmuidzinas
- Department of Molecular Biology, Bristol-Myers Squibb Pharmaceutical Research Institute, Princeton, NJ 08543-4000
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