151
|
Yoshida A, Ookura M, Zokumasu K, Ueda T. Gö6976, a FLT3 kinase inhibitor, exerts potent cytotoxic activity against acute leukemia via inhibition of survivin and MCL-1. Biochem Pharmacol 2014; 90:16-24. [PMID: 24735609 DOI: 10.1016/j.bcp.2014.04.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2014] [Revised: 04/03/2014] [Accepted: 04/04/2014] [Indexed: 02/07/2023]
Abstract
Mutations of the FMS-like tyrosine kinase 3 (FLT3) have been reported in about a third of patients with acute myeloid leukemia (AML). The presence of FLT3 mutations confers a poor prognosis. Thus, pharmacological inhibitors of FLT3 are of therapeutic interest for AML. Gö6976 is an indolocarbazole with a similar structural backbone to staurosporine. In the present study, we demonstrated that Gö6976 displays a potent inhibitory activity against recombinant FLT3 using an in vitro kinase assay, with an IC50 value of 0.7nM. Gö6976 markedly inhibited the proliferation of human leukemia cells having FLT3-ITD such as MV4-11 and MOLM13. We also observed that Gö6976 showed minimal toxicity for human normal CD34(+) cells. Gö6976 suppressed the phosphorylation of FLT3 and downstream signaling molecules such as STAT3/5, Erk1/2, and Akt in MV4-11 and MOLM13 cells. Interestingly, induction of apoptosis by Gö6976 was associated with rapid and pronounced down-regulation of the anti-apoptotic protein survivin and MCL-1. Suppression of survivin protein expression by Gö6976 was due to the inhibition of transcription via the suppression of STAT3/5. On the other hand, Gö6976 induced proteasome-mediated degradation of MCL-1. Previously described FLT3 inhibitors such as PKC412 are bound by the human plasma protein, α1-acid glycoprotein, resulting in diminished inhibitory activity against FLT3. In contrast, we found that Gö6976 potently inhibited phosphorylation of FLT3 and exerted cytotoxicity in the presence of human serum. In conclusion, Gö6976 is a potent FLT3 inhibitor that displays a significant antiproliferative activity against leukemia cells with FLT3-ITD through the profound down-regulation of survivin and MCL-1.
Collapse
Affiliation(s)
- Akira Yoshida
- Department of Hematology and Oncology, Faculty of Medicine, University of Fukui, Shimoaizuki 23-3, Mastuoka, Eiheiji-Chou, Fukui 910-1193, Japan; Translational Research Center, University of Fukui, Japan.
| | - Miyuki Ookura
- Department of Hematology and Oncology, Faculty of Medicine, University of Fukui, Shimoaizuki 23-3, Mastuoka, Eiheiji-Chou, Fukui 910-1193, Japan
| | - Kouichi Zokumasu
- Department of Hematology and Oncology, Faculty of Medicine, University of Fukui, Shimoaizuki 23-3, Mastuoka, Eiheiji-Chou, Fukui 910-1193, Japan
| | - Takanori Ueda
- Department of Hematology and Oncology, Faculty of Medicine, University of Fukui, Shimoaizuki 23-3, Mastuoka, Eiheiji-Chou, Fukui 910-1193, Japan
| |
Collapse
|
152
|
Haricharan S, Li Y. STAT signaling in mammary gland differentiation, cell survival and tumorigenesis. Mol Cell Endocrinol 2014; 382:560-569. [PMID: 23541951 PMCID: PMC3748257 DOI: 10.1016/j.mce.2013.03.014] [Citation(s) in RCA: 90] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/11/2013] [Accepted: 03/18/2013] [Indexed: 01/10/2023]
Abstract
The mammary gland is a unique organ that undergoes extensive and profound changes during puberty, menstruation, pregnancy, lactation and involution. The changes that take place during puberty involve large-scale proliferation and invasion of the fat-pad. During pregnancy and lactation, the mammary cells are exposed to signaling pathways that inhibit apoptosis, induce proliferation and invoke terminal differentiation. Finally, during involution the mammary gland is exposed to milk stasis, programmed cell death and stromal reorganization to clear the differentiated milk-producing cells. Not surprisingly, the signaling pathways responsible for bringing about these changes in breast cells are often subverted during the process of tumorigenesis. The STAT family of proteins is involved in every stage of mammary gland development, and is also frequently implicated in breast tumorigenesis. While the roles of STAT3 and STAT5 during mammary gland development and tumorigenesis are well studied, others members, e.g. STAT1 and STAT6, have only recently been observed to play a role in mammary gland biology. Continued investigation into the STAT protein network in the mammary gland will likely yield new biomarkers and risk factors for breast cancer, and may also lead to novel prophylactic or therapeutic strategies against breast cancer.
Collapse
Affiliation(s)
- S Haricharan
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX, USA
| | - Y Li
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX, USA.
| |
Collapse
|
153
|
Liu S, Walker SR, Nelson EA, Cerulli R, Xiang M, Toniolo PA, Qi J, Stone RM, Wadleigh M, Bradner JE, Frank DA. Targeting STAT5 in hematologic malignancies through inhibition of the bromodomain and extra-terminal (BET) bromodomain protein BRD2. Mol Cancer Ther 2014; 13:1194-205. [PMID: 24435449 DOI: 10.1158/1535-7163.mct-13-0341] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The transcription factor signal STAT5 is constitutively activated in a wide range of leukemias and lymphomas, and drives the expression of genes necessary for proliferation, survival, and self-renewal. Thus, targeting STAT5 is an appealing therapeutic strategy for hematologic malignancies. Given the importance of bromodomain-containing proteins in transcriptional regulation, we considered the hypothesis that a pharmacologic bromodomain inhibitor could inhibit STAT5-dependent gene expression. We found that the small-molecule bromodomain and extra-terminal (BET) bromodomain inhibitor JQ1 decreases STAT5-dependent (but not STAT3-dependent) transcription of both heterologous reporter genes and endogenous STAT5 target genes. JQ1 reduces STAT5 function in leukemia and lymphoma cells with constitutive STAT5 activation, or inducibly activated by cytokine stimulation. Among the BET bromodomain subfamily of proteins, it seems that BRD2 is the critical mediator for STAT5 activity. In experimental models of acute T-cell lymphoblastic leukemias, where activated STAT5 contributes to leukemia cell survival, Brd2 knockdown or JQ1 treatment shows strong synergy with tyrosine kinase inhibitors (TKI) in inducing apoptosis in leukemia cells. In contrast, mononuclear cells isolated form umbilical cord blood, which is enriched in normal hematopoietic precursor cells, were unaffected by these combinations. These findings indicate a unique functional association between BRD2 and STAT5, and suggest that combinations of JQ1 and TKIs may be an important rational strategy for treating leukemias and lymphomas driven by constitutive STAT5 activation.
Collapse
Affiliation(s)
- Suhu Liu
- Authors' Affiliations: Department of Medical Oncology, Dana-Farber Cancer Institute, and Departments of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts; and Department of Immunology, Institute of Biomedical Science, University of Sao Paulo, Sao Paulo, Brazil
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
154
|
Differential requirement for wild-type Flt3 in leukemia initiation among mouse models of human leukemia. Exp Hematol 2013; 42:192-203.e1. [PMID: 24269847 DOI: 10.1016/j.exphem.2013.11.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2013] [Revised: 10/08/2013] [Accepted: 11/12/2013] [Indexed: 11/24/2022]
Abstract
FLT3 is one of the most frequently mutated genes in acute leukemias. However, the role in leukemogenesis of wild-type (wt) FLT3, which is highly expressed in many hematologic malignancies, is unclear. We show here that in mouse models established by retroviral transduction of leukemic fusion proteins, deletion of Flt3 strongly inhibits MLL-ENL and to lesser extent p210(BCR-ABL)-induced leukemogenesis, but has no effect in MLL-AF9 or AML1-ETO9a models. Flt3 acts at the level of leukemic stem cells (LSCs), as a fraction of LSCs in MLL-ENL, but not in MLL-AF9-induced leukemia, expressed Flt3 in vivo, and Flt3 expression on LSCs was associated with leukemia development in this model. Furthermore, efficiency of MLL-ENL, but not of MLL-AF9-induced leukemia induction was significantly enhanced after transduction of Flt3(+) compared to Flt3(-) wt myeloid progenitors. However, Flt3 is not required for immortalization of bone marrow cells in vitro by MLL-ENL and does not affect colony formation by MLL-ENL LSCs in vitro, suggesting that in vitro models do not reflect the in vivo biology of MLL-ENL leukemia with respect to Flt3 requirement. We conclude that wt Flt3 plays a role in leukemia initiation in vivo, which is, however, not universal.
Collapse
|
155
|
Seedhouse CH, Mills KI, Ahluwalia S, Grundy M, Shang S, Burnett AK, Russell NH, Pallis M. Distinct poor prognostic subgroups of acute myeloid leukaemia, FLT3-ITD and P-glycoprotein-positive, have contrasting levels of FOXO1. Leuk Res 2013; 38:131-7. [PMID: 24268349 DOI: 10.1016/j.leukres.2013.10.030] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2013] [Revised: 10/29/2013] [Accepted: 10/31/2013] [Indexed: 11/30/2022]
Abstract
Regulation of ABCB1 (P-glycoprotein/Pgp) in AML was investigated. In a historical cohort with Pgp and transcriptional regulator expression profiling data available (n=141), FOXO1 correlated with Pgp protein expression. This was confirmed in an independent cohort (n=204). Down-regulation (siRNA) or hyperactivation (nicotinamide) of FOXO1 led to corresponding changes in Pgp. Low FOXO1 expression correlated with FLT3-ITDs (p<0.001) and siRNA inhibition of FLT3-ITD up-regulated FOXO1. As FOXO1 is a key growth regulator, it may underpin biological differences between Pgp-positive clones (low WBC and primary resistant disease) and clones with a FLT3-ITD (associated with a high WBC and early relapse).
Collapse
Affiliation(s)
| | - Ken I Mills
- Centre for Cancer Research and Cell Biology (CCRCB), Queen's University Belfast, Belfast, UK
| | - Sophie Ahluwalia
- Department of Haematology, University of Nottingham, Nottingham, UK
| | - Martin Grundy
- Department of Haematology, University of Nottingham, Nottingham, UK; Clinical Haematology, Nottingham University Hospitals, Nottingham, UK
| | - Shili Shang
- Department of Haematology, University of Nottingham, Nottingham, UK
| | - Alan K Burnett
- Department of Haematology, Cardiff University, Cardiff, UK
| | - Nigel H Russell
- Department of Haematology, University of Nottingham, Nottingham, UK; Clinical Haematology, Nottingham University Hospitals, Nottingham, UK
| | - Monica Pallis
- Clinical Haematology, Nottingham University Hospitals, Nottingham, UK
| |
Collapse
|
156
|
Kornblau SM, Qutub A, Yao H, York H, Qiu YH, Graber D, Ravandi F, Cortes J, Andreeff M, Zhang N, Coombes KR. Proteomic profiling identifies distinct protein patterns in acute myelogenous leukemia CD34+CD38- stem-like cells. PLoS One 2013; 8:e78453. [PMID: 24223100 PMCID: PMC3816767 DOI: 10.1371/journal.pone.0078453] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2013] [Accepted: 09/10/2013] [Indexed: 01/10/2023] Open
Abstract
Acute myeloid leukemia (AML) is believed to arise from leukemic stem-like cells (LSC) making understanding the biological differences between LSC and normal stem cells (HSC) or common myeloid progenitors (CMP) crucial to understanding AML biology. To determine if protein expression patterns were different in LSC compared to other AML and CD34+ populations, we measured the expression of 121 proteins by Reverse Phase Protein Arrays (RPPA) in 5 purified fractions from AML marrow and blood samples: Bulk (CD3/CD19 depleted), CD34-, CD34+(CMP), CD34+CD38+ and CD34+CD38-(LSC). LSC protein expression differed markedly from Bulk (n=31 cases, 93/121 proteins) and CD34+ cells (n= 30 cases, 88/121 proteins) with 54 proteins being significantly different (31 higher, 23 lower) in LSC than in either Bulk or CD34+ cells. Sixty-seven proteins differed significantly between CD34+ and Bulk blasts (n=69 cases). Protein expression patterns in LSC and CD34+ differed markedly from normal CD34+ cells. LSC were distinct from CD34+ and Bulk cells by principal component and by protein signaling network analysis which confirmed individual protein analysis. Potential targetable submodules in LSC included the proteins PU.1(SP1), P27, Mcl1, HIF1α, cMET, P53, Yap, and phospho-Stats 1, 5 and 6. Protein expression and activation in LSC differs markedly from other blast populations suggesting that studies of AML biology should be performed in LSC.
Collapse
Affiliation(s)
- Steven M. Kornblau
- Department of Leukemia, The University of Texas M.D. Anderson Cancer Center, Houston, Texas, United States of America
- * E-mail:
| | - Amina Qutub
- Department of Bioengineering, Rice University, Houston, Texas, United States of America
| | - Hui Yao
- Department of Bioinformatics and Computational Biology, The University of Texas M.D. Anderson Cancer Center, Houston, Texas, United States of America
| | - Heather York
- Department of Bioengineering, Rice University, Houston, Texas, United States of America
| | - Yi Hua Qiu
- Department of Leukemia, The University of Texas M.D. Anderson Cancer Center, Houston, Texas, United States of America
| | - David Graber
- Department of Leukemia, The University of Texas M.D. Anderson Cancer Center, Houston, Texas, United States of America
| | - Farhad Ravandi
- Department of Leukemia, The University of Texas M.D. Anderson Cancer Center, Houston, Texas, United States of America
| | - Jorge Cortes
- Department of Leukemia, The University of Texas M.D. Anderson Cancer Center, Houston, Texas, United States of America
| | - Michael Andreeff
- Department of Leukemia, The University of Texas M.D. Anderson Cancer Center, Houston, Texas, United States of America
| | - Nianxiang Zhang
- Department of Bioinformatics and Computational Biology, The University of Texas M.D. Anderson Cancer Center, Houston, Texas, United States of America
| | - Kevin R. Coombes
- Department of Bioinformatics and Computational Biology, The University of Texas M.D. Anderson Cancer Center, Houston, Texas, United States of America
| |
Collapse
|
157
|
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.
Collapse
|
158
|
Dorritie KA, McCubrey JA, Johnson DE. STAT transcription factors in hematopoiesis and leukemogenesis: opportunities for therapeutic intervention. Leukemia 2013; 28:248-57. [PMID: 23797472 DOI: 10.1038/leu.2013.192] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2013] [Revised: 05/30/2013] [Accepted: 06/13/2013] [Indexed: 12/14/2022]
Abstract
Signal transducer and activator of transcription (STAT) proteins comprise a family of transcription factors that are activated by cytokines, hormones and growth factors. The activation of STAT proteins plays a key role in the production of mature hematopoietic cells via effects on cellular proliferation, survival and lineage-specific differentiation. Emerging evidence also demonstrates frequent, constitutive activation of STATs in primary leukemia specimens. Moreover, roles for STATs in promoting leukemia development have been delineated in numerous preclinical studies. This review summarizes our current understanding of STAT protein involvement in normal hematopoiesis and leukemogenesis, as well as recent advances in the development and testing of novel STAT inhibitors.
Collapse
Affiliation(s)
- K A Dorritie
- Department of Medicine, University of Pittsburgh and the University of Pittsburgh Cancer Institute, Pittsburgh, PA, USA
| | - J A McCubrey
- Department of Microbiology and Immunology, School of Medicine, East Carolina University, Greenville, NC, USA
| | - D E Johnson
- Department of Pharmacology and Chemical Biology, University of Pittsburgh and the University of Pittsburgh Cancer Institute, Pittsburgh, PA, USA
| |
Collapse
|
159
|
Bosman MCJ, Schuringa JJ, Quax WJ, Vellenga E. Bortezomib sensitivity of acute myeloid leukemia CD34+ cells can be enhanced by targeting the persisting activity of NF-κB and the accumulation of MCL-1. Exp Hematol 2013; 41:530-538.e1. [DOI: 10.1016/j.exphem.2013.02.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2012] [Revised: 02/01/2013] [Accepted: 02/05/2013] [Indexed: 10/27/2022]
|
160
|
Quantitation of hematogones at the time of engraftment is a useful prognostic indicator in allogeneic hematopoietic stem cell transplantation. Blood 2013; 121:840-8. [DOI: 10.1182/blood-2012-02-409607] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Key Points
Quantitation of hematogones at engraftment is useful to predict prognosis of patients treated with allogeneic stem cell transplantation.
Collapse
|
161
|
Daver N, Strati P, Jabbour E, Kadia T, Luthra R, Wang S, Patel K, Ravandi F, Cortes J, Qin Dong X, Kantarjian H, Garcia-Manero G. FLT3 mutations in myelodysplastic syndrome and chronic myelomonocytic leukemia. Am J Hematol 2013; 88:56-9. [PMID: 23115106 DOI: 10.1002/ajh.23345] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2012] [Accepted: 09/21/2012] [Indexed: 11/12/2022]
Abstract
FMS-like tyrosine kinase III (FLT3) mutations occur in one-third of acute myeloid leukemia (AML) patients and predict poor outcome. The incidence and impact of FLT3 in myelodysplastic syndrome (MDS) and chronic myelomonocytic leukemia (CMML) is unknown. We conducted a retrospective review to identify WHO MDS and CMML patients with FLT3 mutations at diagnosis. A total of 2,119 patients with MDS and 466 patients with CMML were evaluated at MD Anderson between 1997 and 2010. Of these, FLT3 mutation analysis was performed on 1,232 (58%) MDS and 302 (65%) CMML patients. FLT3 mutations were identified in 12 (0.95%) MDS patients: 9 (75%) had FLT3-ITD mutation and 3 had FLT3-tyrosine kinase domain (TKD) mutation. MDS patients with FLT3 mutations were younger (P = 0.02) and presented as RAEB (P = 0.03) more frequently. Median overall survival (OS) for FLT3-mutated MDS patients was 19.0 months versus 16.4 months for FLT3-nonmutated MDS patients (P = 0.08). FLT3 mutations were identified in 13 (4.3%) CMML patients: 8 had FLT3-ITD mutation and 5 had FLT3-TKD mutation. There were no significant differences in demographic and disease characteristics among CMML patients with and without FLT3 mutations. Median OS for FLT3-mutated CMML patients was 10.8 months versus 21.3 months for FLT3-nonmutated CMML patients (P = 0.12). FLT3 occurs in MDS and CMML at a lower frequency than AML and does not predict poor outcome.
Collapse
MESH Headings
- Adolescent
- Adult
- Aged
- Aged, 80 and over
- DNA Mutational Analysis
- Female
- Humans
- Incidence
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/diagnosis
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/genetics
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/mortality
- Leukemia, Myeloid, Acute/diagnosis
- Leukemia, Myeloid, Acute/genetics
- Leukemia, Myeloid, Acute/mortality
- Male
- Middle Aged
- Mutation
- Myelodysplastic Syndromes/diagnosis
- Myelodysplastic Syndromes/genetics
- Myelodysplastic Syndromes/mortality
- Prognosis
- Protein Structure, Tertiary
- Retrospective Studies
- Survival Rate
- fms-Like Tyrosine Kinase 3/genetics
Collapse
Affiliation(s)
- Naval Daver
- Department of Leukemia and Hematopathology, The University of Texas, MD Anderson Cancer Center, Houston, USA
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
162
|
Schnetzke U, Fischer M, Kuhn AK, Spies-Weisshart B, Zirm E, Hochhaus A, Müller JP, Scholl S. The E3 ubiquitin ligase TRAF6 inhibits LPS-induced AKT activation in FLT3-ITD-positive MV4-11 AML cells. J Cancer Res Clin Oncol 2012; 139:605-15. [DOI: 10.1007/s00432-012-1362-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2012] [Accepted: 12/05/2012] [Indexed: 01/11/2023]
|
163
|
Rahmani M, Aust MM, Attkisson E, Williams DC, Ferreira-Gonzalez A, Grant S. Dual inhibition of Bcl-2 and Bcl-xL strikingly enhances PI3K inhibition-induced apoptosis in human myeloid leukemia cells through a GSK3- and Bim-dependent mechanism. Cancer Res 2012; 73:1340-51. [PMID: 23243017 DOI: 10.1158/0008-5472.can-12-1365] [Citation(s) in RCA: 118] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Effects of concomitant inhibition of the PI3K/AKT/mTOR pathway and Bcl-2/Bcl-xL (BCL2L1) were examined in human myeloid leukemia cells. Tetracycline-inducible Bcl-2 and Bcl-xL dual knockdown sharply increased PI3K/AKT/mTOR inhibitor lethality. Conversely, inducible knockdown or dominant-negative AKT increased, whereas constitutively active AKT reduced lethality of the Bcl-2/Bcl-xL inhibitor ABT-737. Furthermore, PI3K/mTOR inhibitors (e.g., BEZ235 and PI-103) synergistically increased ABT-737-mediated cell death in multiple leukemia cell lines and reduced colony formation in leukemic, but not normal, CD34+ cells. Notably, increased lethality was observed in four of six primary acute myelogenous leukemia (AML) specimens. Responding, but not nonresponding, samples exhibited basal AKT phosphorylation. PI3K/mTOR inhibitors markedly downregulated Mcl-1 but increased Bim binding to Bcl-2/Bcl-xL; the latter effect was abrogated by ABT-737. Combined treatment also markedly diminished Bax/Bak binding to Mcl-1, Bcl-2, or Bcl-xL. Bax, Bak, or Bim (BCL2L11) knockdown or Mcl-1 overexpression significantly diminished regimen-induced apoptosis. Interestingly, pharmacologic inhibition or short hairpin RNA knockdown of GSK3α/β significantly attenuated Mcl-1 downregulation and decreased apoptosis. In a systemic AML xenograft model, dual tetracycline-inducible knockdown of Bcl-2/Bcl-xL sharply increased BEZ235 antileukemic effects. In a subcutaneous xenograft model, BEZ235 and ABT-737 coadministration significantly diminished tumor growth, downregulated Mcl-1, activated caspases, and prolonged survival. Together, these findings suggest that antileukemic synergism between PI3K/AKT/mTOR inhibitors and BH3 mimetics involves multiple mechanisms, including Mcl-1 downregulation, release of Bim from Bcl-2/Bcl-xL as well as Bak and Bax from Mcl-1/Bcl-2/Bcl-xL, and GSK3α/β, culminating in Bax/Bak activation and apoptosis. They also argue that combining PI3K/AKT/mTOR inhibitors with BH3 mimetics warrants attention in AML, particularly in the setting of basal AKT activation and/or addiction.
Collapse
Affiliation(s)
- Mohamed Rahmani
- Department of Medicine, Virginia Commonwealth University, The Virginia Institute for Molecular Medicine and Massey Cancer Center, Richmond, VA 23298, USA.
| | | | | | | | | | | |
Collapse
|
164
|
Kupsa T, Milos Horacek J, Jebavy L. The role of cytokines in acute myeloid leukemia: A systematic review. Biomed Pap Med Fac Univ Palacky Olomouc Czech Repub 2012; 156:291-301. [DOI: 10.5507/bp.2012.108] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2012] [Accepted: 12/03/2012] [Indexed: 12/21/2022] Open
|
165
|
Chu SH, Heiser D, Li L, Kaplan I, Collector M, Huso D, Sharkis SJ, Civin C, Small D. FLT3-ITD knockin impairs hematopoietic stem cell quiescence/homeostasis, leading to myeloproliferative neoplasm. Cell Stem Cell 2012; 11:346-58. [PMID: 22958930 PMCID: PMC3725984 DOI: 10.1016/j.stem.2012.05.027] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2011] [Revised: 01/30/2012] [Accepted: 05/24/2012] [Indexed: 11/25/2022]
Abstract
Internal tandem duplication (ITD) mutations within the FMS-like tyrosine kinase-3 (FLT3) render the receptor constitutively active driving proliferation and survival in leukemic blasts. Expression of FLT3-ITD from the endogenous promoter in a murine knockin model results in progenitor expansion and a myeloproliferative neoplasm. In this study, we show that this expansion begins with overproliferation within a compartment of normally quiescent long-term hematopoietic stem cells (LT-HSCs), which become rapidly depleted. This depletion is reversible upon treatment with the small molecule inhibitor Sorafenib, which also ablates the disease. Although the normal LT-HSC has been defined as FLT3(-) by flow cytometric detection, we demonstrate that FLT3 is capable of playing a role within this compartment by examining the effects of constitutively activated FLT3-ITD. This indicates an important link between stem cell quiescence/homeostasis and myeloproliferative disease while also giving novel insight into the emergence of FLT3-ITD mutations in the evolution of leukemic transformation.
Collapse
Affiliation(s)
- S. Haihua Chu
- Department of Oncology; Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, Baltimore MD 21231, USA
| | - Diane Heiser
- Department of Oncology; Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, Baltimore MD 21231, USA
- Center for Stem Cell Biology & Regenerative Medicine, University of Maryland School of Medicine, Baltimore MD 21201, USA
| | - Li Li
- Department of Oncology; Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, Baltimore MD 21231, USA
| | - Ian Kaplan
- Department of Oncology; Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, Baltimore MD 21231, USA
- Pediatric Oncology; Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, Baltimore MD 21231, USA
| | - Michael Collector
- Department of Oncology; Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, Baltimore MD 21231, USA
| | - David Huso
- Department of Oncology; Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, Baltimore MD 21231, USA
- Molecular and Comparative Pathobiology; Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, Baltimore MD 21231, USA
| | - Saul J Sharkis
- Department of Oncology; Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, Baltimore MD 21231, USA
| | - Curt Civin
- Center for Stem Cell Biology & Regenerative Medicine, University of Maryland School of Medicine, Baltimore MD 21201, USA
| | - Don Small
- Department of Oncology; Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, Baltimore MD 21231, USA
- Pediatric Oncology; Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, Baltimore MD 21231, USA
| |
Collapse
|
166
|
Pietschmann K, Bolck HA, Buchwald M, Spielberg S, Polzer H, Spiekermann K, Bug G, Heinzel T, Böhmer FD, Krämer OH. Breakdown of the FLT3-ITD/STAT5 axis and synergistic apoptosis induction by the histone deacetylase inhibitor panobinostat and FLT3-specific inhibitors. Mol Cancer Ther 2012; 11:2373-83. [PMID: 22942377 DOI: 10.1158/1535-7163.mct-12-0129] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Activating mutations of the class III receptor tyrosine kinase FLT3 are the most frequent molecular aberration in acute myeloid leukemia (AML). Mutant FLT3 accelerates proliferation, suppresses apoptosis, and correlates with poor prognosis. Therefore, it is a promising therapeutic target. Here, we show that RNA interference against FLT3 with an internal tandem duplication (FLT3-ITD) potentiates the efficacy of the histone deacetylase inhibitor (HDACi) panobinostat (LBH589) against AML cells expressing FLT3-ITD. Similar to RNA interference, tyrosine kinase inhibitors (TKI; AC220/cpd.102/PKC412) in combination with LBH589 exhibit superior activity against AML cells. Median dose-effect analyses of drug-induced apoptosis rates of AML cells (MV4-11 and MOLM-13) revealed combination index (CI) values indicating strong synergism. AC220, the most potent and FLT3-specific TKI, shows highest synergism with LBH589 in the low nanomolar range. A 4-hour exposure to LBH589 + AC220 already generates more than 50% apoptosis after 24 hours. Different cell lines lacking FLT3-ITD as well as normal peripheral blood mononuclear cells are not significantly affected by LBH589 + TKI, showing the specificity of this treatment regimen. Immunoblot analyses show that LBH589 + TKI induce apoptosis via degradation of FLT3-ITD and its prosurvival target STAT5. Previously, we showed the LBH589-induced proteasomal degradation of FLT3-ITD. Here, we show that activated caspase-3 also contributes to the degradation of FLT3-ITD and that STAT5 is a direct target of this protease. Our data strongly emphasize HDACi/TKI drug combinations as promising modality for the treatment of FLT3-ITD-positive AMLs.
Collapse
Affiliation(s)
- Kristin Pietschmann
- Institute of Biochemistry and Biophysics, Center for Molecular Biomedicine, Friedrich-Schiller University, Hans-Knöll-Str. 2, Jena 07745, Germany
| | | | | | | | | | | | | | | | | | | |
Collapse
|
167
|
Pallis M, Abdul-Aziz A, Burrows F, Seedhouse C, Grundy M, Russell N. The multi-kinase inhibitor TG02 overcomes signalling activation by survival factors to deplete MCL1 and XIAP and induce cell death in primary acute myeloid leukaemia cells. Br J Haematol 2012; 159:191-203. [PMID: 22934750 DOI: 10.1111/bjh.12018] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2012] [Accepted: 07/16/2012] [Indexed: 01/10/2023]
Abstract
The novel multi-kinase inhibitor TG02 has selectivity against cell cycle and transcriptional cyclin dependent kinases (CDKs) as well as fms-like tyrosine kinase receptor-3 (FLT3). Inhibition of transcriptional CDKs preferentially depletes short-lived proteins such as MCL1. We evaluated the in vitro toxicity of TG02 to primary acute myeloid leukaemia (AML) cells in the presence of survival signalling pathway activation by cytokines and fibronectin. One hundred nanomolar TG02 induced a median decrease of 40% in bulk cell survival and 43% in the CD34(+) CD38(-) CD123(+) subset. A 90% inhibitory concentration of 500 nmol/l indicated that TG02 toxicity is not halted by protective cell cycle arrest. Samples with FLT3 internal tandem duplication were not preferentially targeted. By flow cytometry, TG02 treatment caused loss of RNA Polymerase II serine 2 phosphorylation in patient samples, which correlated strongly with BAX activation (R(2) =0·89), suggesting these as potential biomarkers for clinical studies. MCL1 and XIAP expression also decreased. Repeated brief exposure to TG02 in MOLM-13 cells did not result in compensatory up-regulation of survival protein expression. In conclusion, TG02 is potently cytotoxic towards CD34(+) CD38(-) CD123(+) and bulk AML cells, despite protective signalling pathway activation. This antitumour activity is most likely mediated by dephosphorylation of RNA Polymerase II leading to depletion of survival molecules such as MCL1 and XIAP, with subsequent BAX activation and apoptosis.
Collapse
Affiliation(s)
- Monica Pallis
- Academic Haematology, Nottingham University Hospitals City Campus, Clinical Sciences Building, Nottingham, UK.
| | | | | | | | | | | |
Collapse
|
168
|
Williams AB, Nguyen B, Li L, Brown P, Levis M, Leahy D, Small D. Mutations of FLT3/ITD confer resistance to multiple tyrosine kinase inhibitors. Leukemia 2012; 27:48-55. [PMID: 22858906 DOI: 10.1038/leu.2012.191] [Citation(s) in RCA: 77] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
FMS-like tyrosine kinase 3 (FLT3) normally functions in the survival/proliferation of hematopoietic stem/progenitor cells, but its constitutive activation by internal tandem duplication (ITD) mutations correlates with a poor prognosis in AML. The development of FLT3 tyrosine kinase inhibitors (TKI) is a promising strategy, but resistance that arises during the course of treatment caused by secondary mutations within the mutated gene itself poses a significant challenge. In an effort to predict FLT3 resistance mutations that might develop in patients, we used saturation mutagenesis of FLT3/ITD followed by selection of transfected cells in FLT3 TKI. We identified F621L, A627P, F691L and Y842C mutations in FLT3/ITD that confer varying levels of resistance to FLT3 TKI. Western blotting confirmed that some FLT3 TKI were ineffective at inhibiting FLT3 autophosphorylation and signaling through MAP kinase, STAT5 and AKT in some mutants. Balb/c mice transplanted with the FLT3/ITD Y842C mutation confirmed resistance to sorafenib in vivo but not to lestaurtinib. These results indicate a growing number of FLT3 mutations that are likely to be encountered in patients. Such knowledge, combined with known remaining sensitivity to other FLT3 TKI, will be important to establish as secondary drug treatments that can be substituted when these mutants are encountered.
Collapse
Affiliation(s)
- A B Williams
- Department of Oncology, Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, Baltimore, MD 21231, USA
| | | | | | | | | | | | | |
Collapse
|
169
|
Zauli G, Celeghini C, Melloni E, Voltan R, Ongari M, Tiribelli M, di Iasio MG, Lanza F, Secchiero P. The sorafenib plus nutlin-3 combination promotes synergistic cytotoxicity in acute myeloid leukemic cells irrespectively of FLT3 and p53 status. Haematologica 2012; 97:1722-30. [PMID: 22689683 DOI: 10.3324/haematol.2012.062083] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
BACKGROUND Both the multi-kinase inhibitor sorafenib and the small molecule inhibitor of the MDM2/p53 interaction, nutlin-3, used alone, have shown promising anti-leukemic activity in acute myeloid leukemia cells. Thus, in this study we investigated the effect of the combination of sorafenib plus nutlin-3 in acute myeloid leukemia. DESIGN AND METHODS Primary acute myeloid leukemia blasts (n=13) and FLT3(wild-type)/p53(wild-type) (OCI-AML3), FLT3(mutated)/p53(wild-type) (MOLM), FLT3(mutated)/p53(mutated) (MV4-11), FLT3(wild-type)/p53(deleted) (HL60) or FLT3(wild-type)/p53(mutated) (NB4) acute myeloid cell lines were exposed to sorafenib, used alone or in association with nutlin-3 at a 1:1 ratio, in a range of clinically achievable concentrations (1-10 μM). Induction of apoptosis and autophagy was evaluated by transmission electron microscopy and by specific flow cytometry analyses. The levels of Mcl-1, p53 and Bak proteins were analyzed by western blotting. Knock-down of Bax and Bak gene expression was performed in transfection experiments with specific short interfering RNA. RESULTS The sorafenib+nutlin-3 drug combination exhibits synergistic cytotoxicity in primary acute myeloid leukemia blasts and in acute myeloid leukemia cell lines with maximal cytotoxicity in FLT3(mutated) MV4-11 and MOLM, followed by the FLT3(wild-type) OCI-AML3, HL60 and NB4 cell lines. The cytotoxic activity of sorafenib+nutlin-3 was characterized by an increase of both apoptosis and autophagy. Moreover, Bax and Bak showed prominent roles in mediating the decrease of cell viability in response to the drug combination in p53(wild-type) OCI-AML3 and p53(deleted) HL-60 cells, respectively, as demonstrated in transfection experiments performed with specific short interfering RNA. CONCLUSIONS Our data demonstrate that acute myeloid leukemia cells show a variable but overall good susceptibility to the innovative therapeutic combination of sorafenib+nutlin-3, which differentially involves the pro-apoptotic Bcl-2 family members Bax and Bak in p53(wild-type) and p53(deleted) cells.
Collapse
Affiliation(s)
- Giorgio Zauli
- Institute for Maternal and Child Health, IRCCS Burlo Garofolo, Trieste, Italy.
| | | | | | | | | | | | | | | | | |
Collapse
|
170
|
Zirm E, Spies-Weisshart B, Heidel F, Schnetzke U, Böhmer FD, Hochhaus A, Fischer T, Scholl S. Ponatinib may overcome resistance of FLT3-ITD harbouring additional point mutations, notably the previously refractory F691I mutation. Br J Haematol 2012; 157:483-92. [DOI: 10.1111/j.1365-2141.2012.09085.x] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2011] [Accepted: 02/03/2012] [Indexed: 12/16/2022]
Affiliation(s)
- Elisabeth Zirm
- Department of Haematology/Oncology; Clinic for Internal Medicine II; Jena University Hospital; Jena
| | - Bärbel Spies-Weisshart
- Department of Haematology/Oncology; Clinic for Internal Medicine II; Jena University Hospital; Jena
| | - Florian Heidel
- Department of Haematology/Oncology; Otto-von-Guericke-University; Magdeburg; Germany
| | - Ulf Schnetzke
- Department of Haematology/Oncology; Clinic for Internal Medicine II; Jena University Hospital; Jena
| | | | - Andreas Hochhaus
- Department of Haematology/Oncology; Clinic for Internal Medicine II; Jena University Hospital; Jena
| | - Thomas Fischer
- Department of Haematology/Oncology; Otto-von-Guericke-University; Magdeburg; Germany
| | - Sebastian Scholl
- Department of Haematology/Oncology; Clinic for Internal Medicine II; Jena University Hospital; Jena
| |
Collapse
|
171
|
Targeting MCL-1 sensitizes FLT3-ITD-positive leukemias to cytotoxic therapies. Blood Cancer J 2012; 2:e60. [PMID: 22829255 PMCID: PMC3317524 DOI: 10.1038/bcj.2012.5] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2011] [Revised: 01/11/2012] [Accepted: 01/20/2012] [Indexed: 11/08/2022] Open
Abstract
Patients suffering from acute myeloid leukemias (AML) bearing FMS-like tyrosine kinase-3-internal tandem duplications (FLT3-ITD) have poor outcomes following cytarabine- and anthracyclin-based induction therapy. To a major part this is attributed to drug resistance of FLT3-ITD-positive leukemic cells. Against this background, we have devised an antibody array approach to identify proteins, which are differentially expressed by hematopoietic cells in relation to activated FLT3 signaling. Selective upregulation of antiapoptotic myeloid cell leukemia-1 (MCL-1) was found in FLT3-ITD-positive cell lines and primary mononuclear cells from AML patients as compared with FLT3-wild-type controls. Upregulation of MCL-1 was dependent on FLT3 signaling as confirmed by its reversion upon pharmacological inhibition of FLT3 activity by the kinase inhibitor PKC412 as well as siRNA-mediated suppression of FLT3. Heterologously expressed MCL-1 substituted for FLT3 signaling by conferring resistance of hematopoietic cells to antileukemia drugs such as cytarabine and daunorubicin, and to the proapoptotic BH3 mimetic ABT-737. Conversely, suppression of endogenous MCL-1 by siRNA or by flavopiridol treatment sensitized FLT3-ITD-expressing hematopoietic cells to cytotoxic and targeted therapeutics. In conclusion, MCL-1 is an essential effector of FLT3-ITD-mediated drug resistance. Therapeutic targeting of MCL-1 is a promising strategy to overcome drug resistance in FLT3-ITD-positive AML.
Collapse
|
172
|
CD44 activation enhances acute monoblastic leukemia cell survival via Mcl-1 upregulation. Leuk Res 2012; 36:358-62. [DOI: 10.1016/j.leukres.2011.09.022] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2011] [Revised: 09/15/2011] [Accepted: 09/19/2011] [Indexed: 11/21/2022]
|
173
|
Sorafenib treatment of FLT3-ITD(+) acute myeloid leukemia: favorable initial outcome and mechanisms of subsequent nonresponsiveness associated with the emergence of a D835 mutation. Blood 2012; 119:5133-43. [PMID: 22368270 DOI: 10.1182/blood-2011-06-363960] [Citation(s) in RCA: 226] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Internal tandem duplication (ITD) of the fms-related tyrosine kinase-3 (FLT3) gene occurs in 30% of acute myeloid leukemias (AMLs) and confers a poor prognosis. Thirteen relapsed or chemo-refractory FLT3-ITD(+) AML patients were treated with sorafenib (200-400 mg twice daily). Twelve patients showed clearance or near clearance of bone marrow myeloblasts after 27 (range 21-84) days with evidence of differentiation of leukemia cells. The sorafenib response was lost in most patients after 72 (range 54-287) days but the FLT3 and downstream effectors remained suppressed. Gene expression profiling showed that leukemia cells that have become sorafenib resistant expressed several genes including ALDH1A1, JAK3, and MMP15, whose functions were unknown in AML. Nonobese diabetic/severe combined immunodeficiency mice transplanted with leukemia cells from patients before and during sorafenib resistance recapitulated the clinical results. Both ITD and tyrosine kinase domain mutations at D835 were identified in leukemia initiating cells (LICs) from samples before sorafenib treatment. LICs bearing the D835 mutant have expanded during sorafenib treatment and dominated during the subsequent clinical resistance. These results suggest that sorafenib have selected more aggressive sorafenib-resistant subclones carrying both FLT3-ITD and D835 mutations, and might provide important leads to further improvement of treatment outcome with FLT3 inhibitors.
Collapse
|
174
|
Reckzeh K, Bereshchenko O, Mead A, Rehn M, Kharazi S, Jacobsen SE, Nerlov C, Cammenga J. Molecular and cellular effects of oncogene cooperation in a genetically accurate AML mouse model. Leukemia 2012; 26:1527-36. [PMID: 22318449 DOI: 10.1038/leu.2012.37] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Biallelic CEBPA mutations and FMS-like tyrosine kinase receptor 3 (FLT3) length mutations are frequently identified in human acute myeloid leukemia (AML) with normal cytogenetics. However, the molecular and cellular mechanisms of oncogene cooperation remain unclear because of a lack of disease models. We have generated an AML mouse model using knockin mouse strains to study cooperation of an internal tandem duplication (ITD) mutation in the Flt3 gene with commonly observed CCAAT/enhancer binding protein alpha (C/EBPα) mutations. This study provides evidence that FLT3 ITD cooperates in leukemogenesis by enhancing the generation of leukemia-initiating granulocyte-monocyte progenitors (GMPs) otherwise prevented by a block in differentiation and skewed lineage priming induced by biallelic C/EBPα mutations. These cellular changes are accompanied by an upregulation of hematopoietic stem cell and STAT5 target genes. By gene expression analysis in premalignant populations, we further show a role of FLT3 ITD in activating genes involved in survival/transformation and chemoresistance. Both multipotent progenitors and GMP cells contain the potential to induce AML similar to corresponding cells in human AML samples showing that this model resembles human disease.
Collapse
Affiliation(s)
- K Reckzeh
- Department of Molecular Medicine and Gene Therapy, Lund University, Lund, Sweden
| | | | | | | | | | | | | | | |
Collapse
|
175
|
Secchiero P, Melloni E, Voltan R, Norcio A, Celeghini C, Zauli G. MCL1 down-regulation plays a critical role in mediating the higher anti-leukaemic activity of the multi-kinase inhibitor Sorafenib with respect to Dasatinib. Br J Haematol 2012; 157:510-4. [PMID: 22313359 DOI: 10.1111/j.1365-2141.2012.09042.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
|
176
|
Soliera AR, Mariani SA, Audia A, Lidonnici MR, Addya S, Ferrari-Amorotti G, Cattelani S, Manzotti G, Fragliasso V, Peterson L, Perini G, Holyoake TL, Calabretta B. Gfi-1 inhibits proliferation and colony formation of p210BCR/ABL-expressing cells via transcriptional repression of STAT 5 and Mcl-1. Leukemia 2012; 26:1555-63. [PMID: 22285998 DOI: 10.1038/leu.2012.19] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Expression of the transcription repressor Gfi-1 is required for the maintenance of murine hematopoietic stem cells. In human cells, ectopic expression of Gfi-1 inhibits and RNA interference-mediated Gfi-1 downregulation enhances proliferation and colony formation of p210BCR/ABL expressing cells. To investigate the molecular mechanisms that may explain the effects of perturbing Gfi-1 expression in human cells, Gfi-1-regulated genes were identified by microarray analysis in K562 cells expressing the tamoxifen-regulated Gfi-1-ER protein. STAT 5B and Mcl-1, two genes important for the proliferation and survival of hematopoietic stem cells, were identified as direct and functionally relevant Gfi-1 targets in p210BCR/ABL-transformed cells because: (i) their expression and promoter activity was repressed by Gfi-1 and (ii) when constitutively expressed blocked the proliferation and colony formation inhibitory effects of Gfi-1. Consistent with these findings, genetic or pharmacological inhibition of STAT 5 and/or Mcl-1 markedly suppressed proliferation and colony formation of K562 and CD34+ chronic myelogenous leukemia (CML) cells. Together, these studies suggest that the Gfi-1STAT 5B/Mcl-1 regulatory pathway identified here can be modulated to suppress the proliferation and survival of p210BCR/ABL-transformed cells including CD34+ CML cells.
Collapse
Affiliation(s)
- A R Soliera
- Department of Cancer Biology and Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
177
|
Page BDG, Khoury H, Laister RC, Fletcher S, Vellozo M, Manzoli A, Yue P, Turkson J, Minden MD, Gunning PT. Small molecule STAT5-SH2 domain inhibitors exhibit potent antileukemia activity. J Med Chem 2012; 55:1047-55. [PMID: 22148584 DOI: 10.1021/jm200720n] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
A growing body of evidence shows that Signal Transducer and Activator of Transcription 5 (STAT5) protein, a key member of the STAT family of signaling proteins, plays a pivotal role in the progression of many human cancers, including acute myeloid leukemia and prostate cancer. Unlike STAT3, where significant medicinal effort has been expended to identify potent direct inhibitors, Stat5 has been poorly investigated as a molecular therapeutic target. Thus, in an effort to identify direct inhibitors of STAT5 protein, we conducted an in vitro screen of a focused library of SH2 domain binding salicylic acid-containing inhibitors (∼150) against STAT5, as well as against STAT3 and STAT1 proteins for SH2 domain selectivity. We herein report the identification of several potent (K(i) < 5 μM) and STAT5 selective (>3-fold specificity for STAT5 cf. STAT1 and STAT3) inhibitors, BP-1-107, BP-1-108, SF-1-087, and SF-1-088. Lead agents, evaluated in K562 and MV-4-11 human leukemia cells, showed potent induction of apoptosis (IC(50)'s ∼ 20 μM) which correlated with potent and selective suppression of STAT5 phosphorylation, as well as inhibition of STAT5 target genes cyclin D1, cyclin D2, C-MYC, and MCL-1. Moreover, lead agent BP-1-108 showed negligible cytotoxic effects in normal bone marrow cells not expressing activated STAT5 protein. Inhibitors identified in this study represent some of the most potent direct small molecule, nonphosphorylated inhibitors of STAT5 to date.
Collapse
Affiliation(s)
- Brent D G Page
- Department of Chemistry, University of Toronto, 3359 Mississauga Road North, Mississauga, ON, L5L 1C6, Canada
| | | | | | | | | | | | | | | | | | | |
Collapse
|
178
|
Reikvam H, Hatfield KJ, Ersvaer E, Hovland R, Skavland J, Gjertsen BT, Petersen K, Bruserud O. Expression profile of heat shock proteins in acute myeloid leukaemia patients reveals a distinct signature strongly associated with FLT3 mutation status--consequences and potentials for pharmacological intervention. Br J Haematol 2011; 156:468-80. [PMID: 22150087 DOI: 10.1111/j.1365-2141.2011.08960.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Heat shock proteins (HSPs) are molecular chaperones that assist proteins in their folding to native structures. HSPs are regarded as possible therapeutic targets in acute myeloid leukaemia (AML). We used bioinformatical approaches to characterize the HSP profile in AML cells from 75 consecutive patients, in addition to the effect of the HSP90 inhibitor 17-DMAG. Patients harbouring a FLT3-internal tandem duplication (FLT3-ITD) were extensively overrepresented in the cluster with high HSP levels, indicating a strong dependence of HSPs in stabilizing FLT3-ITD encoded oncoproteins. FLT3 ligation further increased the levels of HSP90 and its co-chaperone HSP70. HSP90 inhibition had a stronger pro-apoptotic effect for AML cells with FLT3-ITD than for cells with wild-type FLT3, whereas the anti-proliferative effect of HSP90 inhibition was similar for the two patient subsets. HSP90 inhibition altered the constitutive cytokine release profile in an anti-angiogenic direction independent of FLT3 mutational status: (i) pro-angiogenic CXCL8, MMP-2 and MMP-9 showed a stronger decrease than anti-angiogenic CXCL9-11, (ii) the Tie-2 agonist Ang-1 showed a stronger decrease than the potentially antagonistic Ang-2, and (iii) VEGF and HGF levels were decreased. Finally, HSP90 inhibition counteracted the leukaemia-stimulating effect of endothelial cells. Our studies demonstrate that HSP90 inhibition mediates anti-leukaemic effects through both direct and indirect activity.
Collapse
Affiliation(s)
- Håkon Reikvam
- Division for Haematology, Institute of Medicine, University of Bergen, Norway
| | | | | | | | | | | | | | | |
Collapse
|
179
|
Bar-Natan M, Nelson EA, Walker SR, Kuang Y, Distel RJ, Frank DA. Dual inhibition of Jak2 and STAT5 enhances killing of myeloproliferative neoplasia cells. Leukemia 2011; 26:1407-10. [DOI: 10.1038/leu.2011.338] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|
180
|
p53 activation of mesenchymal stromal cells partially abrogates microenvironment-mediated resistance to FLT3 inhibition in AML through HIF-1α-mediated down-regulation of CXCL12. Blood 2011; 118:4431-9. [PMID: 21868571 DOI: 10.1182/blood-2011-02-334136] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Fms-like tyrosine kinase-3 (FLT3) inhibitors have been used to overcome the dismal prognosis of acute myeloid leukemia (AML) with FLT3 mutations. Clinical results with FLT3 inhibitor monotherapy have shown that bone marrow responses are commonly less pronounced than peripheral blood responses. We investigated the role of p53 in bone marrow stromal cells in stromal cell-mediated resistance to FLT3 inhibition in FLT3 mutant AML. While the FLT3 inhibitor FI-700 induced apoptosis in FLT3 mutant AML cells, apoptosis induction was diminished under stromal coculture conditions. Protection appeared to be mediated, in part, by CXCL12 (SDF-1)/CXCR4 signaling. The protective effect of stromal cells was significantly reduced by pre-exposure to the HDM2 inhibitor Nutlin-3a. p53 activation by Nutlin-3a was not cytotoxic to stromal cells, but reduced CXCL12 mRNA levels and secretion of CXCL12 partially through p53-mediated HIF-1α down-regulation. Results show that p53 activation in stroma cells blunts stroma cell-mediated resistance to FLT3 inhibition, in part through down-regulation of CXCL12. This is the first report of Nutlin effect on the bone marrow environment. We suggest that combinations of HDM2 antagonists and FLT3 inhibitors may be effective in clinical trials targeting mutant FLT3 leukemias.
Collapse
|
181
|
Li L, Modi H, McDonald T, Rossi J, Yee JK, Bhatia R. A critical role for SHP2 in STAT5 activation and growth factor-mediated proliferation, survival, and differentiation of human CD34+ cells. Blood 2011; 118:1504-15. [PMID: 21670473 PMCID: PMC3156043 DOI: 10.1182/blood-2010-06-288910] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2010] [Accepted: 05/27/2011] [Indexed: 12/15/2022] Open
Abstract
SHP2, a cytoplasmic protein-tyrosine phosphatase encoded by the PTPN11 gene, plays a critical role in developmental hematopoiesis in the mouse, and gain-of-function mutations of SHP2 are associated with hematopoietic malignancies. However, the role of SHP2 in adult hematopoiesis has not been addressed in previous studies. In addition, the role of SHP2 in human hematopoiesis has not been described. These questions are of considerable importance given the interest in development of SHP2 inhibitors for cancer treatment. We used shRNA-mediated inhibition of SHP2 expression to investigate the function of SHP2 in growth factor (GF) signaling in normal human CD34(+) cells. SHP2 knockdown resulted in markedly reduced proliferation and survival of cells cultured with GF, and reduced colony-forming cell growth. Cells expressing gain-of-function SHP2 mutations demonstrated increased dependency on SHP2 expression for survival compared with cells expressing wild-type SHP2. SHP2 knockdown was associated with significantly reduced myeloid and erythroid differentiation with retention of CD34(+) progenitors with enhanced proliferative capacity. Inhibition of SHP2 expression initially enhanced and later inhibited STAT5 phosphorylation and reduced expression of the antiapoptotic genes MCL1 and BCLXL. These results indicate an important role for SHP2 in STAT5 activation and GF-mediated proliferation, survival, and differentiation of human progenitor cells.
Collapse
Affiliation(s)
- Liang Li
- Division of Hematopoietic Stem Cell and Leukemia Research, City of Hope Nationa, Medical Center, Duarte, CA, USA
| | | | | | | | | | | |
Collapse
|
182
|
Bal G, Kamhieh-Milz J, Futschik M, Häupl T, Salama A, Moldenhauer A. Transcriptional profiling of the hematopoietic support of interleukin-stimulated human umbilical vein endothelial cells (HUVECs). Cell Transplant 2011; 21:251-67. [PMID: 21669038 DOI: 10.3727/096368911x580581] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Endothelial cells can be successfully used to maintain or increase the number of hematopoietic stem cells in vitro. Previously we identified hematopoietic progenitor cell (HPC) expansion or survival benefit induced by IL-1β-, IL-3-, and IL-6-stimulated human umbilical vein endothelial cell (HUVEC) supernatants. In order to identify molecular mechanisms that support hematopoiesis, we examined the time-dependent expression profiles of IL-1β-, IL-3-, and IL-6-stimulated HUVECs via microarray. Here, we present 24 common upregulated elements and three common downregulated elements of IL-1β- and IL-3-stimulated HUVECs, with these factors exhibiting great potential for the observed HPC expansion. Furthermore, metabolic pathway analysis resulted in the identification of nonproteinogenic factors such as prostaglandin E(2) (PGE(2)) and nitric oxide (NO) and determined their HPC expansion potential via delta, methylcellulose, and cobblestone assays. We confirmed PGE(2) and spermine as hematopoietic expansion factors. Furthermore, we identified several factors such as SSAT, extracellular matrix components, microRNA21, and a microvesicle-mediated cross-talk between the endothelium and HPCs that may play a crucial role in determining stem cell fate. Our results suggest that microarray in combination with functional annotations is a convenient method to identify novel factors with great impact on HPC proliferation and differentiation.
Collapse
Affiliation(s)
- Gürkan Bal
- Institute for Transfusion Medicine, Charité-Universitätsmedizin Berlin, Berlin, Germany.
| | | | | | | | | | | |
Collapse
|
183
|
Abstract
Pim kinases are Ser/Thr kinases with multiple substrates that affect survival pathways. These proteins are overexpressed in acute myeloid leukemia (AML) blasts and we hypothesized that Pim kinase inhibition would affect AML cell survival. Imidazo[1,2-b]pyridazine compound, SGI-1776 inhibits Pim-1, Pim-2 and Pim-3, and was evaluated in AML-cell line, -xenograft model, and -primary blasts. Treatment of AML cells with SGI-1776 results in a concentration-dependent induction of apoptosis and we investigated its effect on Pim kinase functions. Phosphorylation of traditional Pim kinase targets, c-Myc(Ser62) and 4E-BP1 (Thr36/Thr47), were both decreased in actively cycling AML cell lines MV-4-11, MOLM-13 and OCI-AML-3. Levels of antiapoptotic proteins Bcl-2, Bcl-x(L), XIAP, and proapoptotic Bak and Bax were unchanged; however, a significant reduction in Mcl-1 was observed. This was correlated with inhibition of global RNA and protein synthesis and MCL-1 transcript decline after SGI-1776 treatment. These data suggest that SGI-1776 mechanism in AML involves Mcl-1 protein reduction. Consistent with cell line data, xenograft model studies with mice bearing MV-4-11 tumors showed efficacy with SGI-1776. Importantly, SGI-1776 was also cytotoxic in AML primary cells, irrespective of FLT3 mutation status and resulted in Mcl-1 protein decline. Pim kinase inhibition may be a new strategy for AML treatment.
Collapse
|
184
|
TIM-3 is a promising target to selectively kill acute myeloid leukemia stem cells. Cell Stem Cell 2011; 7:708-17. [PMID: 21112565 DOI: 10.1016/j.stem.2010.11.014] [Citation(s) in RCA: 347] [Impact Index Per Article: 26.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2010] [Revised: 08/23/2010] [Accepted: 10/06/2010] [Indexed: 02/07/2023]
Abstract
Acute myeloid leukemia (AML) originates from self-renewing leukemic stem cells (LSCs), an ultimate therapeutic target for AML. Here we identified T cell immunoglobulin mucin-3 (TIM-3) as a surface molecule expressed on LSCs in most types of AML except for acute promyelocytic leukemia, but not on normal hematopoietic stem cells (HSCs). TIM-3(+) but not TIM-3⁻ AML cells reconstituted human AML in immunodeficient mice, suggesting that the TIM-3(+) population contains most, if not all, of functional LSCs. We established an anti-human TIM-3 mouse IgG2a antibody having complement-dependent and antibody-dependent cellular cytotoxic activities. This antibody did not harm reconstitution of normal human HSCs, but blocked engraftment of AML after xenotransplantation. Furthermore, when it is administered into mice grafted with human AML, this treatment dramatically diminished their leukemic burden and eliminated LSCs capable of reconstituting human AML in secondary recipients. These data suggest that TIM-3 is one of the promising targets to eradicate AML LSCs.
Collapse
|
185
|
Goardon N, Marchi E, Atzberger A, Quek L, Schuh A, Soneji S, Woll P, Mead A, Alford KA, Rout R, Chaudhury S, Gilkes A, Knapper S, Beldjord K, Begum S, Rose S, Geddes N, Griffiths M, Standen G, Sternberg A, Cavenagh J, Hunter H, Bowen D, Killick S, Robinson L, Price A, Macintyre E, Virgo P, Burnett A, Craddock C, Enver T, Jacobsen SEW, Porcher C, Vyas P. Coexistence of LMPP-like and GMP-like leukemia stem cells in acute myeloid leukemia. Cancer Cell 2011; 19:138-52. [PMID: 21251617 DOI: 10.1016/j.ccr.2010.12.012] [Citation(s) in RCA: 468] [Impact Index Per Article: 36.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/07/2010] [Revised: 10/23/2010] [Accepted: 12/15/2010] [Indexed: 12/13/2022]
Abstract
The relationships between normal and leukemic stem/progenitor cells are unclear. We show that in ∼80% of primary human CD34+ acute myeloid leukemia (AML), two expanded populations with hemopoietic progenitor immunophenotype coexist in most patients. Both populations have leukemic stem cell (LSC) activity and are hierarchically ordered; one LSC population gives rise to the other. Global gene expression profiling shows the LSC populations are molecularly distinct and resemble normal progenitors but not stem cells. The more mature LSC population most closely mirrors normal granulocyte-macrophage progenitors (GMP) and the immature LSC population a previously uncharacterized progenitor functionally similar to lymphoid-primed multipotential progenitors (LMPPs). This suggests that in most cases primary CD34+ AML is a progenitor disease where LSCs acquire abnormal self-renewal potential.
Collapse
MESH Headings
- Adult
- Aged
- Aged, 80 and over
- Animals
- Antigens, CD/metabolism
- Antigens, CD34/metabolism
- Cell Differentiation/physiology
- Cell Lineage/physiology
- Gene Expression Profiling
- Graft Survival
- Granulocyte-Macrophage Progenitor Cells/cytology
- Granulocyte-Macrophage Progenitor Cells/metabolism
- Hematopoietic Stem Cells/cytology
- Hematopoietic Stem Cells/metabolism
- Humans
- Immunophenotyping
- Leukemia, Myeloid, Acute/metabolism
- Leukemia, Myeloid, Acute/pathology
- Leukocyte Common Antigens/metabolism
- Lymphoid Progenitor Cells/cytology
- Lymphoid Progenitor Cells/metabolism
- Mice
- Mice, Inbred NOD
- Mice, SCID
- Middle Aged
- Neoplastic Stem Cells/metabolism
- Neoplastic Stem Cells/pathology
- Neoplastic Stem Cells/transplantation
- Transplantation, Heterologous/pathology
- Young Adult
Collapse
|
186
|
|
187
|
Shima H, Takubo K, Tago N, Iwasaki H, Arai F, Takahashi T, Suda T. Acquisition of G₀ state by CD34-positive cord blood cells after bone marrow transplantation. Exp Hematol 2010; 38:1231-40. [PMID: 20800645 DOI: 10.1016/j.exphem.2010.08.004] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2010] [Revised: 08/04/2010] [Accepted: 08/12/2010] [Indexed: 10/19/2022]
Abstract
OBJECTIVE Hematopoietic stem cells are kept in a quiescent state in the hypoxic area of the bone marrow, which is essential for hematopoietic stem cell maintenance. However, when and how hematopoietic stem cells acquire their hypoxic state and maintain quiescence has not been fully elucidated. The aim of this study was to understand this process in human hematopoietic stem cells after bone marrow transplantation. MATERIALS AND METHODS Human CD34-positive cord blood cells were transplanted into nonobese diabetic/severe combined immunodeficient interleukin-2 receptor γ chain knockout mice. Cell cycle and hypoxia assay analyses were performed, to identify changes in the characteristics of human hematopoietic stem cells following transplantation. Quantitative real-time reverse transcription polymerase chain reaction analysis was used to analyze the transcriptional changes accompanying this transition. RESULTS Engrafted primitive lineage-negative CD34-positive CD38-negative cells acquired hypoxic state and quiescence in the recipient bone marrow between 4 and 8 weeks, and between 8 and 12 weeks after transplantation, respectively. During 4 and 8 weeks after transplantation, changes in the transcription levels of G₀ regulatory factors, such as CCNC and RBL1, and stem cell regulators, such as Flt3, were also seen, which may be related to the characteristic changes in the cell cycle or oxygenation state. CONCLUSIONS Behavioral changes of hematopoietic stem cells in their cell cycle and oxygenation state during and after bone marrow engraftment may provide insights into hematopoietic stem cell regulation, mediating the improvement of clinical hematopoietic stem cell transplantation protocols and the eradication of leukemia stem cells.
Collapse
Affiliation(s)
- Haruko Shima
- Department of Cell Differentiation, The Sakaguchi Laboratory of Developmental Biology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo, Japan
| | | | | | | | | | | | | |
Collapse
|
188
|
Abstract
Mutations within the FMS-like tyrosine kinase 3 (FLT3) gene on chromosome 13q12 have been detected in up to 35% of acute myeloid leukemia (AML) patients and represent one of the most frequently identified genetic alterations in AML. Over the last years, FLT3 has emerged as a promising molecular target in therapy of AML. Here, we review results of clinical trials and of correlative laboratory studies using small molecule FLT3 tyrosine kinase inhibitors (TKIs) in AML patients. We also review mechanisms of primary and secondary drug resistance to FLT3-TKI, and from the data currently available we summarize lessons learned from FLT3-TKI monotherapy. Finally, for using FLT3 as a molecular target, we discuss novel strategies to overcome treatment failure and to improve FLT3 inhibitor therapy.
Collapse
|
189
|
Li G, Miskimen KL, Wang Z, Xie XY, Tse W, Gouilleux F, Moriggl R, Bunting KD. Effective targeting of STAT5-mediated survival in myeloproliferative neoplasms using ABT-737 combined with rapamycin. Leukemia 2010; 24:1397-405. [PMID: 20535152 PMCID: PMC2921023 DOI: 10.1038/leu.2010.131] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Signal transducer and activator of transcription-5 (STAT5) is a critical transcription factor for normal hematopoiesis and its sustained activation is associated with hematologic malignancy. A persistently active mutant of STAT5 (STAT5aS711F) associates with Grb2 associated binding protein 2 (Gab2) in myeloid leukemias and promotes growth in vitro through AKT activation. Here we have retrovirally transduced wild-type or Gab2−/− mouse bone marrow cells expressing STAT5aS711F and transplanted into irradiated recipient mice to test an in vivo myeloproliferative disease (MPD) model. To target Gab2-independent AKT/mTOR activation, wild-type mice were treated separately with rapamycin. In either case, mice lacking Gab2 or treated with rapamycin displayed attenuated myeloid hyperplasia and modestly improved survival, but the effects were not cytotoxic and were reversible. To improve upon this approach, in vitro targeting of STAT5-mediated AKT/mTOR using rapamycin was combined with inhibition of the STAT5 direct target genes bcl-2 and bcl-XL using ABT-737. Striking synergy with both drugs was observed in mouse BaF3 cells expressing STAT5aS711F, TEL-JAK2, or BCR-ABL and in the relatively single agent-resistant human BCR-ABL positive K562 cell line. Therefore, targeting distinct STAT5 mediated survival signals, e.g. bcl-2/bcl-XL and AKT/mTOR may be an effective therapeutic approach for human myeloproliferative neoplasms.
Collapse
Affiliation(s)
- G Li
- Division of Hematology-Oncology, Department of Medicine, Case Western Reserve University, Cleveland, OH, USA
| | | | | | | | | | | | | | | |
Collapse
|
190
|
Xiang Z, Luo H, Payton JE, Cain J, Ley TJ, Opferman JT, Tomasson MH. Mcl1 haploinsufficiency protects mice from Myc-induced acute myeloid leukemia. J Clin Invest 2010; 120:2109-18. [PMID: 20484815 PMCID: PMC2877934 DOI: 10.1172/jci39964] [Citation(s) in RCA: 91] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2009] [Accepted: 02/03/2010] [Indexed: 11/17/2022] Open
Abstract
Antiapoptotic BCL2 family members have been implicated in the pathogenesis of acute myelogenous leukemia (AML), but the functional significance and relative importance of individual proteins (e.g., BCL2, BCL-XL, and myeloid cell leukemia 1 [MCL1]) remain poorly understood. Here, we examined the expression of BCL2, BCL-XL, and MCL1 in primary human hematopoietic subsets and leukemic blasts from AML patients and found that MCL1 transcripts were consistently expressed at high levels in all samples tested. Consistent with this, Mcl1 protein was also highly expressed in myeloid leukemic blasts in a mouse Myc-induced model of AML. We used this model to test the hypothesis that Mcl1 facilitates AML development by allowing myeloid progenitor cells to evade Myc-induced cell death. Indeed, activation of Myc for 7 days in vivo substantially increased myeloid lineage cell numbers, whereas hematopoietic stem, progenitor, and B-lineage cells were depleted. Furthermore, Mcl1 haploinsufficiency abrogated AML development. In addition, deletion of a single allele of Mcl1 from fully transformed AML cells substantially prolonged the survival of transplanted mice. Conversely, the rapid lethality of disease was restored by coexpression of Bcl2 and Myc in Mcl1-haploinsufficient cells. Together, these data demonstrate a critical and dose-dependent role for Mcl1 in AML pathogenesis in mice and suggest that MCL1 may be a promising therapeutic target in patients with de novo AML.
Collapse
Affiliation(s)
- Zhifu Xiang
- Department of Medicine, Division of Oncology, and
Department of Pathology and Immunology, Siteman Cancer Center, Washington University School of Medicine, St. Louis, Missouri, USA.
OncoMed Pharmaceutical Inc., Redwood City, California, USA.
Department of Biochemistry, St. Jude Children’s Research Hospital, Memphis, Tennessee, USA
| | - Hui Luo
- Department of Medicine, Division of Oncology, and
Department of Pathology and Immunology, Siteman Cancer Center, Washington University School of Medicine, St. Louis, Missouri, USA.
OncoMed Pharmaceutical Inc., Redwood City, California, USA.
Department of Biochemistry, St. Jude Children’s Research Hospital, Memphis, Tennessee, USA
| | - Jacqueline E. Payton
- Department of Medicine, Division of Oncology, and
Department of Pathology and Immunology, Siteman Cancer Center, Washington University School of Medicine, St. Louis, Missouri, USA.
OncoMed Pharmaceutical Inc., Redwood City, California, USA.
Department of Biochemistry, St. Jude Children’s Research Hospital, Memphis, Tennessee, USA
| | - Jennifer Cain
- Department of Medicine, Division of Oncology, and
Department of Pathology and Immunology, Siteman Cancer Center, Washington University School of Medicine, St. Louis, Missouri, USA.
OncoMed Pharmaceutical Inc., Redwood City, California, USA.
Department of Biochemistry, St. Jude Children’s Research Hospital, Memphis, Tennessee, USA
| | - Timothy J. Ley
- Department of Medicine, Division of Oncology, and
Department of Pathology and Immunology, Siteman Cancer Center, Washington University School of Medicine, St. Louis, Missouri, USA.
OncoMed Pharmaceutical Inc., Redwood City, California, USA.
Department of Biochemistry, St. Jude Children’s Research Hospital, Memphis, Tennessee, USA
| | - Joseph T. Opferman
- Department of Medicine, Division of Oncology, and
Department of Pathology and Immunology, Siteman Cancer Center, Washington University School of Medicine, St. Louis, Missouri, USA.
OncoMed Pharmaceutical Inc., Redwood City, California, USA.
Department of Biochemistry, St. Jude Children’s Research Hospital, Memphis, Tennessee, USA
| | - Michael H. Tomasson
- Department of Medicine, Division of Oncology, and
Department of Pathology and Immunology, Siteman Cancer Center, Washington University School of Medicine, St. Louis, Missouri, USA.
OncoMed Pharmaceutical Inc., Redwood City, California, USA.
Department of Biochemistry, St. Jude Children’s Research Hospital, Memphis, Tennessee, USA
| |
Collapse
|