51
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FMS-related tyrosine kinase 3. Mol Oncol 2013. [DOI: 10.1017/cbo9781139046947.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
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52
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Reprogramming of MLL-AF9 leukemia cells into pluripotent stem cells. Leukemia 2013; 28:1071-80. [PMID: 24150221 PMCID: PMC4017259 DOI: 10.1038/leu.2013.304] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2013] [Revised: 09/21/2013] [Accepted: 10/03/2013] [Indexed: 02/04/2023]
Abstract
The 'Yamanaka factors' (Oct4, Sox2, Klf4 and c-Myc) are able to generate induced pluripotent stem (iPS) cells from different cell types. However, to what degree primary malignant cells can be reprogrammed into a pluripotent state has not been vigorously assessed. We established an acute myeloid leukemia (AML) model by overexpressing the human mixed-lineage leukemia-AF9 (MLL-AF9) fusion gene in mouse hematopoietic cells that carry Yamanaka factors under the control of doxycycline (Dox). On addition of Dox to the culture, the transplantable leukemia cells were efficiently converted into iPS cells that could form teratomas and produce chimeras. Interestingly, most chimeric mice spontaneously developed the same type of AML. Moreover, both iPS reprogramming and leukemia reinitiation paths could descend from the same leukemia-initiating cell. RNA-seq analysis showed reversible global gene expression patterns between these interchangeable leukemia and iPS cells on activation or reactivation of MLL-AF9, suggesting a sufficient epigenetic force in driving the leukemogenic process. This study represents an important step for further defining the potential interplay between oncogenic molecules and reprogramming factors during MLL leukemogenesis. More importantly, our reprogramming approach may be expanded to characterize a range of hematopoietic malignancies in order to develop new strategies for clinical diagnosis and treatment.
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53
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Albouhair S, Morgado E, Lavau C. Flt3 does not play a critical role in murine myeloid leukemias induced by MLL fusion genes. PLoS One 2013; 8:e72261. [PMID: 23977266 PMCID: PMC3745452 DOI: 10.1371/journal.pone.0072261] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2013] [Accepted: 07/14/2013] [Indexed: 12/29/2022] Open
Abstract
Leukemias harboring MLL translocations are frequent in children and adults, and respond poorly to therapies. The receptor tyrosine kinase FLT3 is highly expressed in these leukemias. In vitro studies have shown that pediatric MLL-rearranged ALL cells are sensitive to FLT3 inhibitors and clinical trials are ongoing to measure their therapeutic efficacy. We sought to determine the contribution of Flt3 in the pathogenesis of MLL-rearranged leukemias using a myeloid leukemia mouse model. Bone marrow from Flt3 null mice transduced with MLL-ENL or MLL-CBP was transplanted into host mice and Flt3−/− leukemias were compared to their Flt3 wild type counterparts. Flt3 deficiency did not delay disease onset and had minimal impact on leukemia characteristics. To determine the anti-leukemic effect of FLT3 inhibition we studied the sensitivity of MLL-ENL leukemia cells to the FLT3 inhibitor PKC412 ex vivo. As previously reported for human MLL-rearranged leukemias, murine MLL-ENL leukemia cells with higher Flt3 levels were more sensitive to the cytotoxicity of PKC412. Interestingly, Flt3 deficient leukemia samples also displayed some sensitivity to PKC412. Our findings demonstrate that myeloid leukemias induced by MLL-rearranged genes are not dependent upon Flt3 signaling. They also highlight the discrepancy between the sensitivity of cells to Flt3 inhibition in vitro and the lack of contribution of Flt3 to the pathogenesis of MLL-rearranged leukemias in vivo.
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Affiliation(s)
| | - Ester Morgado
- Centre National de la Recherche Scientifique, UMR7151, Paris, France
| | - Catherine Lavau
- Centre National de la Recherche Scientifique, UMR7151, Paris, France
- * E-mail:
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54
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Adamaki M, Lambrou GI, Athanasiadou A, Tzanoudaki M, Vlahopoulos S, Moschovi M. Implication of IRF4 aberrant gene expression in the acute leukemias of childhood. PLoS One 2013; 8:e72326. [PMID: 23977280 PMCID: PMC3744475 DOI: 10.1371/journal.pone.0072326] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2013] [Accepted: 07/08/2013] [Indexed: 12/13/2022] Open
Abstract
The most frequent targets of genetic alterations in human leukemias are transcription factor genes with essential functions in normal blood cell development. The Interferon Regulatory Factor 4 (IRF4) gene encodes a transcription factor important for key developmental stages of hematopoiesis, with known oncogenic implications in multiple myeloma, adult leukemias and lymphomas. Very few studies have reported an association of IRF4 with childhood malignancy, whereas high transcript levels have been observed in the more mature immunophenotype of ALL. Our aim was to investigate the expression levels of IRF4 in the diagnostic samples of pediatric leukemias and compare them to those of healthy controls, in order to determine aberrant gene expression and whether it extends to leukemic subtypes other than the relatively mature ALL subpopulation. Quantitative real-time RT-PCR methodology was used to investigate IRF4 expression in 58 children with acute leukemias, 4 leukemic cell lines and 20 healthy children. We show that aberrant IRF4 gene expression is implicated in a variety of leukemic subtypes; higher transcript levels appear in the more immature B-common ALL subtype and in T-cell than in B-cell leukemias, with the highest expression levels appearing in the AML group. Interestingly, we show that childhood leukemia, irrespective of subtype or cell maturation stage, is characterised by a minimum of approximately twice the amount of IRF4 gene expression encountered in healthy children. A statistically significant correlation also appeared to exist between high IRF4 expression and relapse. Our results show that ectopic expression of IRF4 follows the reverse expression pattern of what is encountered in normal B-cell development and that there might be a dose-dependency of childhood leukemia for aberrantly expressed IRF4, a characteristic that could be explored therapeutically. It is also suggested that high IRF4 expression might be used as an additional prognostic marker of relapse at diagnosis.
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MESH Headings
- Adolescent
- Case-Control Studies
- Cell Line, Tumor
- Child
- Child, Preschool
- Female
- Gene Expression Regulation, Leukemic
- Humans
- Infant
- Infant, Newborn
- Interferon Regulatory Factors/genetics
- Leukemia, B-Cell/genetics
- Leukemia, B-Cell/mortality
- Leukemia, B-Cell/pathology
- Leukemia, T-Cell/genetics
- Leukemia, T-Cell/mortality
- Leukemia, T-Cell/pathology
- Male
- Precursor B-Cell Lymphoblastic Leukemia-Lymphoma/genetics
- Precursor B-Cell Lymphoblastic Leukemia-Lymphoma/mortality
- Precursor B-Cell Lymphoblastic Leukemia-Lymphoma/pathology
- Precursor Cell Lymphoblastic Leukemia-Lymphoma/genetics
- Precursor Cell Lymphoblastic Leukemia-Lymphoma/mortality
- Precursor Cell Lymphoblastic Leukemia-Lymphoma/pathology
- Recurrence
- Survival Analysis
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Affiliation(s)
- Maria Adamaki
- Pediatric Hematology/Oncology Unit, First Department of Pediatrics, University of Athens, Aghia Sofia Children's Hospital, Athens, Greece.
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55
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The rate of spontaneous mutations in human myeloid cells. Mutat Res 2013; 749:49-57. [PMID: 23748046 DOI: 10.1016/j.mrfmmm.2013.05.004] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2013] [Revised: 05/28/2013] [Accepted: 05/29/2013] [Indexed: 01/09/2023]
Abstract
The mutation rate (μ) is likely to be a key parameter in leukemogenesis, but historically, it has been difficult to measure in humans. The PIG-A gene has some advantages for the detection of spontaneous mutations because it is X-linked, and therefore only one mutation is required to disrupt its function. Furthermore, the PIG-A-null phenotype is readily detected by flow cytometry. Using PIG-A, we have now provided the first in vitro measurement of μ in myeloid cells, using cultures of CD34+ cells that are transduced with either the AML-ETO or the MLL-AF9 fusion genes and expanded with cytokines. For the AML-ETO cultures, the median μ value was ∼9.4×10(-7) (range ∼3.6-23×10(-7)) per cell division. In contrast, few spontaneous mutations were observed in the MLL-AF9 cultures. Knockdown of p53 or introduction of mutant NRAS or FLT3 alleles did not have much of an effect on μ. Based on these data, we provide a model to predict whether hypermutability must occur in the process of leukemogenesis.
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56
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Abstract
Advances in our understanding of the genetic determinants of leukemia have translated to better treatment options and improved survival of patients with acute myeloid and acute lymphoid leukemia. However, some leukemias, such as those bearing 11q23 (MLL) translocations, result in aggressive diseases with a relatively poor prognosis, despite improved treatments such as allogeneic hematopoietic stem cell transplantation. This article will briefly review the functions and regulation of wild-type MLL during normal hematopoiesis, while focusing on recent advances in our understanding of the molecular mechanisms governing MLL leukemias. The transcriptional targets, cooperating signaling pathways and molecular machinery involved in MLL-associated leukemias will be discussed, as well as how these may be harnessed for more personalized treatment of this disease.
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Affiliation(s)
- Andrew G Muntean
- Department of Pathology, Department of Medicine, University of Michigan Medical School, 7520B Medical Science Research Building I, 1301 Catherine Road, Ann Arbor, MI 48109-5602, USA
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57
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The role of tumour-stromal interactions in modifying drug response: challenges and opportunities. Nat Rev Drug Discov 2013; 12:217-28. [PMID: 23449307 DOI: 10.1038/nrd3870] [Citation(s) in RCA: 375] [Impact Index Per Article: 34.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The role of stromal cells and the tumour microenvironment in general in modulating tumour sensitivity is increasingly becoming a key consideration for the development of active anticancer therapeutics. Here, we discuss how these tumour-stromal interactions affect tumour cell signalling, survival, proliferation and drug sensitivity. Particular emphasis is placed on the ability of stromal cells to confer - to tumour cells - resistance or sensitization to different classes of therapeutics, depending on the specific microenvironmental context. The mechanistic understanding of these microenvironmental interactions can influence the evaluation and selection of candidate agents for various cancers, in both the primary site as well as the metastatic setting. Progress in in vitro screening platforms as well as orthotopic and 'orthometastatic' xenograft mouse models has enabled comprehensive characterization of the impact of the tumour microenvironment on therapeutic efficacy. These recent advances can hopefully bridge the gap between preclinical studies and clinical trials of anticancer agents.
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58
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Djiogue S, Nwabo Kamdje AH, Vecchio L, Kipanyula MJ, Farahna M, Aldebasi Y, Seke Etet PF. Insulin resistance and cancer: the role of insulin and IGFs. Endocr Relat Cancer 2013. [PMID: 23207292 DOI: 10.1530/erc-12-0324] [Citation(s) in RCA: 193] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Insulin, IGF1, and IGF2 are the most studied insulin-like peptides (ILPs). These are evolutionary conserved factors well known as key regulators of energy metabolism and growth, with crucial roles in insulin resistance-related metabolic disorders such as obesity, diseases like type 2 diabetes mellitus, as well as associated immune deregulations. A growing body of evidence suggests that insulin and IGF1 receptors mediate their effects on regulating cell proliferation, differentiation, apoptosis, glucose transport, and energy metabolism by signaling downstream through insulin receptor substrate molecules and thus play a pivotal role in cell fate determination. Despite the emerging evidence from epidemiological studies on the possible relationship between insulin resistance and cancer, our understanding on the cellular and molecular mechanisms that might account for this relationship remains incompletely understood. The involvement of IGFs in carcinogenesis is attributed to their role in linking high energy intake, increased cell proliferation, and suppression of apoptosis to cancer risks, which has been proposed as the key mechanism bridging insulin resistance and cancer. The present review summarizes and discusses evidence highlighting recent advances in our understanding on the role of ILPs as the link between insulin resistance and cancer and between immune deregulation and cancer in obesity, as well as those areas where there remains a paucity of data. It is anticipated that issues discussed in this paper will also recover new therapeutic targets that can assist in diagnostic screening and novel approaches to controlling tumor development.
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Affiliation(s)
- Sefirin Djiogue
- Department of Animal Biology and Physiology, University of Yaoundé 1, PO Box 812, Yaoundé, Cameroon
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59
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Krivtsov AV, Figueroa ME, Sinha AU, Stubbs MC, Feng Z, Valk PJM, Delwel R, Döhner K, Bullinger L, Kung AL, Melnick AM, Armstrong SA. Cell of origin determines clinically relevant subtypes of MLL-rearranged AML. Leukemia 2012; 27:852-60. [PMID: 23235717 DOI: 10.1038/leu.2012.363] [Citation(s) in RCA: 153] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Mixed lineage leukemia (MLL)-fusion proteins can induce acute myeloid leukemias (AMLs) from either hematopoietic stem cells (HSCs) or granulocyte-macrophage progenitors (GMPs), but it remains unclear whether the cell of origin influences the biology of the resultant leukemia. MLL-AF9-transduced single HSCs or GMPs could be continuously replated, but HSC-derived clones were more likely than GMP-derived clones to initiate AML in mice. Leukemia stem cells derived from either HSCs or GMPs had a similar immunophenotype consistent with a maturing myeloid cell (LGMP). Gene expression analyses demonstrated that LGMP inherited gene expression programs from the cell of origin including high-level Evi-1 expression in HSC-derived LGMP. The gene expression signature of LGMP derived from HSCs was enriched in poor prognosis human MLL-rearranged AML in three independent data sets. Moreover, global 5'-mC levels were elevated in HSC-derived leukemias as compared with GMP-derived leukemias. This mirrored a difference seen in 5'-mC between MLL-rearranged human leukemias that are either EVI1 positive or EVI1 negative. Finally, HSC-derived leukemias were more resistant to chemotherapy than GMP-derived leukemias. These data demonstrate that the cell of origin influences the gene expression profile, the epigenetic state and the drug response in AML, and that these differences can account for clinical heterogeneity within a molecularly defined group of leukemias.
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Affiliation(s)
- A V Krivtsov
- Division of Hematology/Oncology, Children's Hospital, Boston, MA, USA
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60
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Tam WF, Hähnel PS, Schüler A, Lee BH, Okabe R, Zhu N, Pante SV, Raffel G, Mercher T, Wernig G, Bockamp E, Sasca D, Kreft A, Robinson GW, Hennighausen L, Gilliland DG, Kindler T. STAT5 is crucial to maintain leukemic stem cells in acute myelogenous leukemias induced by MOZ-TIF2. Cancer Res 2012; 73:373-84. [PMID: 23149921 DOI: 10.1158/0008-5472.can-12-0255] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
MOZ-TIF2 is a leukemogenic fusion oncoprotein that confers self-renewal capability to hematopoietic progenitor cells and induces acute myelogenous leukemia (AML) with long latency in bone marrow transplantation assays. Here, we report that FLT3-ITD transforms hematopoietic cells in cooperation with MOZ-TIF2 in vitro and in vivo. Coexpression of FLT3-ITD confers growth factor independent survival/proliferation, shortens disease latency, and results in an increase in the number of leukemic stem cells (LSC). We show that STAT5, a major effector of aberrant FLT3-ITD signal transduction, is both necessary and sufficient for this cooperative effect. In addition, STAT5 signaling is essential for MOZ-TIF2-induced leukemic transformation itself. Lack of STAT5 in fetal liver cells caused rapid differentiation and loss of replating capacity of MOZ-TIF2-transduced cells enriched for LSCs. Furthermore, mice serially transplanted with Stat5(-/-) MOZ-TIF2 leukemic cells develop AML with longer disease latency and finally incomplete penetrance when compared with mice transplanted with Stat5(+/+) MOZ-TIF2 leukemic cells. These data suggest that STAT5AB is required for the self-renewal of LSCs and represents a combined signaling node of FLT3-ITD and MOZ-TIF2 driven leukemogenesis. Therefore, targeting aberrantly activated STAT5 or rewired downstream signaling pathways may be a promising therapeutic option.
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Affiliation(s)
- Winnie F Tam
- Division of Hematology, Department of Medicine, Brigham and Women's Hospital, Boston, MA, USA
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61
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Mullighan CG. Molecular genetics of B-precursor acute lymphoblastic leukemia. J Clin Invest 2012; 122:3407-15. [PMID: 23023711 DOI: 10.1172/jci61203] [Citation(s) in RCA: 181] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
B-precursor acute lymphoblastic leukemia (B-ALL) is the most common childhood tumor and the leading cause of cancer-related death in children and young adults. The majority of B-ALL cases are aneuploid or harbor recurring structural chromosomal rearrangements that are important initiating events in leukemogenesis but are insufficient to explain the biology and heterogeneity of disease. Recent studies have used microarrays and sequencing to comprehensively identify all somatic genetic alterations in acute lymphoblastic leukemia (ALL). These studies have identified cryptic or submicroscopic genetic alterations that define new ALL subtypes, cooperate with known chromosomal rearrangements, and influence prognosis. This article reviews these advances, discusses results from ongoing second-generation sequencing studies of ALL, and highlights challenges and opportunities for future genetic profiling approaches.
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Affiliation(s)
- Charles G Mullighan
- Department of Pathology, St. Jude Children’s Research Hospital, Memphis, Tennessee 38105, USA.
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62
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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.
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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
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63
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Fluvastatin inhibits FLT3 glycosylation in human and murine cells and prolongs survival of mice with FLT3/ITD leukemia. Blood 2012; 120:3069-79. [PMID: 22927251 DOI: 10.1182/blood-2012-01-403493] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
FLT3 is frequently mutated in acute myeloid leukemia (AML), but resistance has limited the benefit of tyrosine kinase inhibitors (TKI). We demonstrate that statins can impair FLT3 glycosylation, thus leading to loss of surface expression and induction of cell death, as well as mitigation of TKI resistance. Immunofluorescence microscopy confirms a reduction in surface localization and an increase in intracellular FLT3/internal tandem duplication (ITD) accumulation. This aberrant localization was associated with increased STAT5 activation but inhibition of both MAPK and AKT phosphorylation. Growth inhibition studies indicate that FLT3/ITD-expressing cells were killed with an IC(50) within a range of 0.2-2μM fluvastatin. Several mechanisms of resistance could be circumvented by fluvastatin treatment. An increase in the IC(50) for inhibition of phosphorylated FLT3/ITD by lestaurtinib caused by exogenous FLT3 ligand, resistance to sorafenib caused by the D835Y or FLT3/ITD N676K mutations, and activation of the IL-3 compensatory pathway were all negated by fluvastatin treatment. Finally, fluvastatin treatment in vivo reduced engraftment of BaF3 FLT3/ITD cells in Balb/c mice. These results demonstrate that statins, a class of drugs already approved by the US Food and Drug Administration, might be repurposed for the management of FLT3 mutant acute myeloid leukemia cases either alone or in conjunction with FLT3 TKI.
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64
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Nishi M, Eguchi-Ishimae M, Wu Z, Gao W, Iwabuki H, Kawakami S, Tauchi H, Inukai T, Sugita K, Hamasaki Y, Ishii E, Eguchi M. Suppression of the let-7b microRNA pathway by DNA hypermethylation in infant acute lymphoblastic leukemia with MLL gene rearrangements. Leukemia 2012; 27:389-97. [DOI: 10.1038/leu.2012.242] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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65
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Deshpande AJ, Bradner J, Armstrong SA. Chromatin modifications as therapeutic targets in MLL-rearranged leukemia. Trends Immunol 2012; 33:563-70. [PMID: 22867873 DOI: 10.1016/j.it.2012.06.002] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2012] [Revised: 05/31/2012] [Accepted: 06/11/2012] [Indexed: 11/26/2022]
Abstract
MLL-rearranged leukemias exemplify malignancies with perturbations of the epigenetic landscape. Specific chromatin modifications that aid in the perpetuation of MLL fusion gene driven oncogenic programs are being defined, presenting novel avenues for therapeutic intervention. Proof-of-concept studies have recently been reported, using small-molecule inhibitors targeting the histone methyltransferase disruptor of telomeric silencing 1-like (DOT1L), or the acetyl-histone binding protein bromodomain containing protein 4 (BRD4) showing potent activity against MLL-rearranged leukemias in preclinical models. It is apparent that intensive efforts will be made toward the further development of small-molecule inhibitors targeting these, and other chromatin-associated protein targets. These studies may lead to the advent of a new generation of much-needed therapeutic modalities in leukemia and other cancers.
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Affiliation(s)
- Aniruddha J Deshpande
- Division of Hematology/Oncology, Children's Hospital, Harvard Medical School, Boston, MA 02215, USA
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66
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Development of a multi-step leukemogenesis model of MLL-rearranged leukemia using humanized mice. PLoS One 2012; 7:e37892. [PMID: 22745659 PMCID: PMC3380045 DOI: 10.1371/journal.pone.0037892] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2012] [Accepted: 04/30/2012] [Indexed: 01/12/2023] Open
Abstract
Mixed-lineage-leukemia (MLL) fusion oncogenes are intimately involved in acute leukemia and secondary therapy-related acute leukemia. To understand MLL-rearranged leukemia, several murine models for this disease have been established. However, the mouse leukemia derived from mouse hematopoietic stem cells (HSCs) may not be fully comparable with human leukemia. Here we developed a humanized mouse model for human leukemia by transplanting human cord blood-derived HSCs transduced with an MLL-AF10 oncogene into a supra-immunodeficient mouse strain, NOD/Shi-scid, IL-2Rγ(-/-) (NOG) mice. Injection of the MLL-AF10-transduced HSCs into the liver of NOG mice enhanced multilineage hematopoiesis, but did not induce leukemia. Because active mutations in ras genes are often found in MLL-related leukemia, we next transduced the gene for a constitutively active form of K-ras along with the MLL-AF10 oncogene. Eight weeks after transplantation, all the recipient mice had developed acute monoblastic leukemia (the M5 phenotype in French-American-British classification). We thus successfully established a human MLL-rearranged leukemia that was derived in vivo from human HSCs. In addition, since the enforced expression of the mutant K-ras alone was insufficient to induce leukemia, the present model may also be a useful experimental platform for the multi-step leukemogenesis model of human leukemia.
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67
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Nin DS, Kok WK, Li F, Takahashi S, Chng WJ, Khan M. Role of misfolded N-CoR mediated transcriptional deregulation of Flt3 in acute monocytic leukemia (AML)-M5 subtype. PLoS One 2012; 7:e34501. [PMID: 22514634 PMCID: PMC3326026 DOI: 10.1371/journal.pone.0034501] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2011] [Accepted: 03/05/2012] [Indexed: 12/03/2022] Open
Abstract
The nuclear receptor co-repressor (N-CoR) is a key component of the generic multi-protein complex involved in transcriptional control. Flt3, a key regulator of hematopoietic cell growth, is frequently deregulated in AML (acute myeloid leukemia). Here, we report that loss of N-CoR-mediated transcriptional control of Flt3 due to misfolding, contributes to malignant growth in AML of the M5 subtype (AML-M5). An analysis of hematopoietic genes in AML cells led to the identification of Flt3 as a transcriptional target of N-CoR. Flt3 level was inversely related to N-CoR status in various leukemia cells. N-CoR was associated with the Flt3 promoter in-vivo, and a reporter driven by the Flt3 promoter was effectively repressed by N-CoR. Blocking N-CoR loss with Genistein; an inhibitor of N-CoR misfolding, significantly down-regulated Flt3 levels regardless of the Flt3 receptor mutational status and promoted the differentiation of AML-M5 cells. While stimulation of the Flt3 receptor with the Flt3 ligand triggered N-CoR loss, Flt3 antibody mediated blockade of Flt3 ligand-receptor binding led to N-CoR stabilization. Genetic ablation of N-CoR potentiated Flt3 ligand induced proliferation of BA/F3 cells. These findings suggest that N-CoR-induced repression of Flt3 might be crucial for limiting the contribution of the Flt3 signaling pathway on the growth potential of leukemic cells and its deregulation due to N-CoR loss in AML-M5, could contribute to malignant growth by conferring a proliferative advantage to the leukemic blasts. Therapeutic restoration of N-CoR function could thus be a useful approach in restricting the contribution of the Flt3 signaling pathway in AML-M5 pathogenesis.
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Affiliation(s)
- Dawn Sijin Nin
- Cancer Science Institute, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
- Departments of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Wai Kay Kok
- Cancer Science Institute, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Feng Li
- Cancer Science Institute, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Shinichiro Takahashi
- Division of Hematology, Kitasato University School of Allied Health Science, Kanagawa, Japan
| | - Wee Joo Chng
- Cancer Science Institute, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
- Departments of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
- Department of Hematology-Oncology, National Cancer Institute of Singapore, National University Health System, Singapore, Singapore
| | - Matiullah Khan
- Cancer Science Institute, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
- Departments of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
- * E-mail:
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68
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Pediatric Acute Leukemia Therapies Informed by Molecular Analysis of High-Risk Disease. Hematology 2011; 2011:366-73. [DOI: 10.1182/asheducation-2011.1.366] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Abstract
The acute leukemias are the most common cancer of children, adolescents, and young adults. These diseases are characterized by a tremendous variability in clinical course, prompting a continuing search for accurate predictors of outcome. Using algorithms based on clinical features at presentation, response to therapy, and several molecular analyses, some patients are diagnosed with features of high-risk disease and comparatively greater risk for relapse. Molecular analyses of patients with high-risk acute leukemias have resulted in an improved understanding of how dysregulated cellular signaling can affect resistance to conventional therapy. Whereas exciting discoveries continue to be made in the identification of relevant molecular biomarkers and targeted therapies, the challenges and opportunities associated with these findings remain to be clearly defined in future clinical trials.
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69
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Mizukawa B, Wei J, Shrestha M, Wunderlich M, Chou FS, Griesinger A, Harris CE, Kumar AR, Zheng Y, Williams DA, Mulloy JC. Inhibition of Rac GTPase signaling and downstream prosurvival Bcl-2 proteins as combination targeted therapy in MLL-AF9 leukemia. Blood 2011; 118:5235-45. [PMID: 21940819 PMCID: PMC3217406 DOI: 10.1182/blood-2011-04-351817] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2011] [Accepted: 09/04/2011] [Indexed: 12/27/2022] Open
Abstract
The Rac family of small Rho GTPases coordinates diverse cellular functions in hematopoietic cells including adhesion, migration, cytoskeleton rearrangements, gene transcription, proliferation, and survival. The integrity of Rac signaling has also been found to critically regulate cellular functions in the initiation and maintenance of hematopoietic malignancies. Using an in vivo gene targeting approach, we demonstrate that Rac2, but not Rac1, is critical to the initiation of acute myeloid leukemia in a retroviral expression model of MLL-AF9 leukemogenesis. However, loss of either Rac1 or Rac2 is sufficient to impair survival and growth of the transformed MLL-AF9 leukemia. Rac2 is known to positively regulate expression of Bcl-2 family proteins toward a prosurvival balance. We demonstrate that disruption of downstream survival signaling through antiapoptotic Bcl-2 proteins is implicated in mediating the effects of Rac2 deficiency in MLL-AF9 leukemia. Indeed, overexpression of Bcl-xL is able to rescue the effects of Rac2 deficiency and MLL-AF9 cells are exquisitely sensitive to direct inhibition of Bcl-2 family proteins by the BH3-mimetic, ABT-737. Furthermore, concurrent exposure to NSC23766, a small-molecule inhibitor of Rac activation, increases the apoptotic effect of ABT-737, indicating the Rac/Bcl-2 survival pathway may be targeted synergistically.
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MESH Headings
- Aminoquinolines/pharmacology
- Animals
- Biphenyl Compounds/pharmacology
- Cell Line, Tumor
- Gene Expression
- Gene Knockdown Techniques
- Humans
- Leukemia, Biphenotypic, Acute/drug therapy
- Leukemia, Biphenotypic, Acute/genetics
- Leukemia, Biphenotypic, Acute/metabolism
- Mice
- Mice, Inbred C57BL
- Mice, Inbred NOD
- Mice, Knockout
- Mice, SCID
- Mice, Transgenic
- Neuropeptides/antagonists & inhibitors
- Neuropeptides/deficiency
- Neuropeptides/genetics
- Nitrophenols/pharmacology
- Piperazines/pharmacology
- Proto-Oncogene Proteins c-bcl-2/antagonists & inhibitors
- Pyrimidines/pharmacology
- Signal Transduction
- Sulfonamides/pharmacology
- Transplantation, Heterologous
- bcl-X Protein/genetics
- rac GTP-Binding Proteins/antagonists & inhibitors
- rac GTP-Binding Proteins/deficiency
- rac GTP-Binding Proteins/genetics
- rac1 GTP-Binding Protein
- RAC2 GTP-Binding Protein
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Affiliation(s)
- Benjamin Mizukawa
- Division of Oncology, Cancer and Blood Diseases Institute, Cincinnati Children’s Hospital Medical Center, OH 45229, USA
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70
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Zuber J, Rappaport AR, Luo W, Wang E, Chen C, Vaseva AV, Shi J, Weissmueller S, Fellmann C, Fellman C, Taylor MJ, Weissenboeck M, Graeber TG, Kogan SC, Vakoc CR, Lowe SW. An integrated approach to dissecting oncogene addiction implicates a Myb-coordinated self-renewal program as essential for leukemia maintenance. Genes Dev 2011; 25:1628-40. [PMID: 21828272 DOI: 10.1101/gad.17269211] [Citation(s) in RCA: 223] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Although human cancers have complex genotypes and are genomically unstable, they often remain dependent on the continued presence of single-driver mutations-a phenomenon dubbed "oncogene addiction." Such dependencies have been demonstrated in mouse models, where conditional expression systems have revealed that oncogenes able to initiate cancer are often required for tumor maintenance and progression, thus validating the pathways they control as therapeutic targets. Here, we implement an integrative approach that combines genetically defined mouse models, transcriptional profiling, and a novel inducible RNAi platform to characterize cellular programs that underlie addiction to MLL-AF9-a fusion oncoprotein involved in aggressive forms of acute myeloid leukemia (AML). We show that MLL-AF9 contributes to leukemia maintenance by enforcing a Myb-coordinated program of aberrant self-renewal involving genes linked to leukemia stem cell potential and poor prognosis in human AML. Accordingly, partial and transient Myb suppression precisely phenocopies MLL-AF9 withdrawal and eradicates aggressive AML in vivo without preventing normal myelopoiesis, indicating that strategies to inhibit Myb-dependent aberrant self-renewal programs hold promise as effective and cancer-specific therapeutics. Together, our results identify Myb as a critical mediator of oncogene addiction in AML, delineate relevant Myb target genes that are amenable to pharmacologic inhibition, and establish a general approach for dissecting oncogene addiction in vivo.
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Affiliation(s)
- Johannes Zuber
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724, USA
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71
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Balgobind BV, Zwaan CM, Pieters R, Van den Heuvel-Eibrink MM. The heterogeneity of pediatric MLL-rearranged acute myeloid leukemia. Leukemia 2011; 25:1239-48. [DOI: 10.1038/leu.2011.90] [Citation(s) in RCA: 105] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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72
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Ziegelberger G, Baum C, Borkhardt A, Cobaleda C, Dasenbrock C, Dehos A, Grosche B, Hauer J, Hornhardt S, Jung T, Kammertoens T, Lagroye I, Lehrach H, Lightfoot T, Little MP, Rossig C, Sanchez-Garcia I, Schrappe M, Schuez J, Shalapour S, Slany R, Stanulla M, Weiss W. Research recommendations toward a better understanding of the causes of childhood leukemia. Blood Cancer J 2011. [PMCID: PMC3255247 DOI: 10.1038/bcj.2010.1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
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73
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Napp J, Mathejczyk JE, Alves F. Optical imaging in vivo with a focus on paediatric disease: technical progress, current preclinical and clinical applications and future perspectives. Pediatr Radiol 2011; 41:161-75. [PMID: 21221568 PMCID: PMC3032188 DOI: 10.1007/s00247-010-1907-0] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/17/2010] [Revised: 09/20/2010] [Accepted: 10/10/2010] [Indexed: 12/30/2022]
Abstract
To obtain information on the occurrence and location of molecular events as well as to track target-specific probes such as antibodies or peptides, drugs or even cells non-invasively over time, optical imaging (OI) technologies are increasingly applied. Although OI strongly contributes to the advances made in preclinical research, it is so far, with the exception of optical coherence tomography (OCT), only very sparingly applied in clinical settings. Nevertheless, as OI technologies evolve and improve continuously and represent relatively inexpensive and harmful methods, their implementation as clinical tools for the assessment of children disease is increasing. This review focuses on the current preclinical and clinical applications as well as on the future potential of OI in the clinical routine. Herein, we summarize the development of different fluorescence and bioluminescence imaging techniques for microscopic and macroscopic visualization of microstructures and biological processes. In addition, we discuss advantages and limitations of optical probes with distinct mechanisms of target-detection as well as of different bioluminescent reporter systems. Particular attention has been given to the use of near-infrared (NIR) fluorescent probes enabling observation of molecular events in deeper tissue.
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Affiliation(s)
- Joanna Napp
- Department of Molecular Biology of Neuronal Signals, Max-Planck-Institute for Experimental Medicine, Hermann-Rein-Str. 3, 37075 Göttingen, Germany ,Department of Hematology and Oncology, University Medical Center Göttingen, Robert-Koch-Str. 40, 37075 Göttingen, Germany
| | - Julia E. Mathejczyk
- Department of Molecular Biology of Neuronal Signals, Max-Planck-Institute for Experimental Medicine, Hermann-Rein-Str. 3, 37075 Göttingen, Germany
| | - Frauke Alves
- Department of Molecular Biology of Neuronal Signals, Max-Planck-Institute for Experimental Medicine, Hermann-Rein-Str. 3, 37075 Göttingen, Germany ,Department of Hematology and Oncology, University Medical Center Göttingen, Robert-Koch-Str. 40, 37075 Göttingen, Germany
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74
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Macy ME, DeRyckere D, Gore L. Vandetanib mediates anti-leukemia activity by multiple mechanisms and interacts synergistically with DNA damaging agents. Invest New Drugs 2010; 30:468-79. [PMID: 21046425 DOI: 10.1007/s10637-010-9572-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2010] [Accepted: 10/20/2010] [Indexed: 12/16/2022]
Abstract
Vandetanib is an orally active small molecule tyrosine kinase inhibitor (TKI) with activity against several pathways implicated in malignancy including the vascular endothelial growth factor receptor pathway, the epidermal growth factor receptor pathway, the platelet derived growth factor receptor β pathway, and REarranged during Transfection pathway. To determine if vandetanib-mediated inhibition of receptor tyrosine kinases is a potential therapeutic strategy for pediatric acute leukemia, these studies aimed to characterize the activity of vandetanib against acute leukemia in vitro. Treatment of leukemia cell lines with vandetanib resulted in a dose-dependent decrease in proliferation and survival. Vandetanib's anti-leukemic activity appeared mediated by multiple mechanisms including accumulation in G1 phase at lower concentrations and apoptosis at higher concentrations. Alterations in cell surface markers also occurred with vandetanib treatment, suggesting induction of differentiation. In combination with DNA damaging agents (etoposide and doxorubicin) vandetanib demonstrated synergistic induction of cell death. However in combination with the anti-metabolite methotrexate, vandetanib had an antagonistic effect on cell death. Although several targets of vandetanib are expressed on acute leukemia cell lines, expression of vandetanib targets did not predict vandetanib sensitivity and alone are therefore not likely candidate biomarkers in patients with acute leukemia. Interactions between vandetanib and standard chemotherapy agents in vitro may help guide choice of combination regimens for further evaluation in the clinical setting for patients with relapsed/refractory acute leukemia. Taken together, these preclinical data support clinical evaluation of vandetanib, in combination with cytotoxic chemotherapy, for pediatric leukemia.
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Affiliation(s)
- Margaret E Macy
- Department of Pediatrics, Section of Hematology, Oncology, and Bone Marrow Transplantation, University of Colorado Denver, 13123 East 16th Avenue B-115, Aurora, CO 80045, USA.
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75
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Gianfelici V, Diverio D, Breccia M, Buffolino S, Derme V, Di Lascio A, Marinelli M, Santangelo S, Meloni G, Foà R. A novel point mutation within the juxtamembrane domain of the flt3 gene in acute myeloid leukemia. Ann Hematol 2010; 90:845-6. [PMID: 20924583 DOI: 10.1007/s00277-010-1092-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2010] [Accepted: 09/23/2010] [Indexed: 11/30/2022]
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76
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Ubiquitin conjugase UBCH8 targets active FMS-like tyrosine kinase 3 for proteasomal degradation. Leukemia 2010; 24:1412-21. [PMID: 20508617 DOI: 10.1038/leu.2010.114] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The class III receptor tyrosine kinase FMS-like tyrosine kinase 3 (FLT3) regulates normal hematopoiesis and immunological functions. Nonetheless, constitutively active mutant FLT3 (FLT3-ITD) causally contributes to transformation and is associated with poor prognosis of acute myeloid leukemia (AML) patients. Histone deacetylase inhibitors (HDACi) can counteract deregulated gene expression profiles and decrease oncoprotein stability, which renders them candidate drugs for AML treatment. However, these drugs have pleiotropic effects and it is often unclear how they correct oncogenic transcriptomes and proteomes. We report here that treatment of AML cells with the HDACi LBH589 induces the ubiquitin-conjugating enzyme UBCH8 and degradation of FLT3-ITD. Gain- and loss-of-function approaches show that UBCH8 and the ubiquitin-ligase SIAH1 physically interact with and target FLT3-ITD for proteasomal degradation. These ubiquitinylating enzymes though have a significantly lesser effect on wild-type FLT3. Furthermore, physiological and pharmacological stimulation of FLT3 phosphorylation, inhibition of FLT3-ITD autophosphorylation and analysis of kinase-inactive FLT3-ITD revealed that tyrosine phosphorylation determines degradation of FLT3 and FLT3-ITD by the proteasome. These results provide novel insights into antileukemic activities of HDACi and position UBCH8, which have been implicated primarily in processes in the nucleus, as a previously unrecognized important modulator of FLT3-ITD stability and leukemic cell survival.
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77
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Abstract
Genomic rearrangements of the locus 11q23 are frequently observed in aggressive acute leukemias with poor prognosis. These chromosomal aberrations fuse the mixed-lineage leukemia (MLL) gene to one of more than 50 partners. The resulting mixed-lineage leukemia fusions often code for chimeric transcriptional activators, which are able to transform normal hematopoietic cells through the deregulation of leukemogenic target genes. This review provides a concise overview about the known functions encoded in MLL and the respective fusion partners. Additionally, the roles of some target genes, as well as co-factors of mixed-lineage leukemia fusion proteins, are described with an emphasis on recent advances potentially uncovering novel therapeutic targets.
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Affiliation(s)
- Christian Bach
- Department of Genetics, University of Erlangen, Erlangen, Germany
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78
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Direct inhibition of the NOTCH transcription factor complex. Nature 2010; 462:182-8. [PMID: 19907488 DOI: 10.1038/nature08543] [Citation(s) in RCA: 613] [Impact Index Per Article: 43.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2009] [Accepted: 09/25/2009] [Indexed: 12/13/2022]
Abstract
Direct inhibition of transcription factor complexes remains a central challenge in the discipline of ligand discovery. In general, these proteins lack surface involutions suitable for high-affinity binding by small molecules. Here we report the design of synthetic, cell-permeable, stabilized alpha-helical peptides that target a critical protein-protein interface in the NOTCH transactivation complex. We demonstrate that direct, high-affinity binding of the hydrocarbon-stapled peptide SAHM1 prevents assembly of the active transcriptional complex. Inappropriate NOTCH activation is directly implicated in the pathogenesis of several disease states, including T-cell acute lymphoblastic leukaemia (T-ALL). The treatment of leukaemic cells with SAHM1 results in genome-wide suppression of NOTCH-activated genes. Direct antagonism of the NOTCH transcriptional program causes potent, NOTCH-specific anti-proliferative effects in cultured cells and in a mouse model of NOTCH1-driven T-ALL.
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79
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Krivtsov AV, Feng Z, Armstrong SA. Transformation from committed progenitor to leukemia stem cells. Ann N Y Acad Sci 2009; 1176:144-9. [PMID: 19796242 DOI: 10.1111/j.1749-6632.2009.04966.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Leukemias are composed of a hierarchy of cells, only a fraction of which have stem cell-like properties and are capable of self-renewal. Mixed lineage leukemia (MLL) fusion proteins produced by translocations involving the MLL gene on chromosome 11q23 confer stem cell-like properties on committed hematopoietic progenitors. This provides an opportunity to assess changes in immunophenotype, gene expression, and epigenetic programs during the transition from a hematopoietic cell with minimal inherent self-renewal capability to cells capable of leukemic self-renewal.
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Affiliation(s)
- Andrei V Krivtsov
- Division of Hematology/Oncology, Children's Hospital, Department of Pediatric Oncology, Dana Farber Cancer Institute, and Harvard Medical School, Boston, Massachusetts 02215, USA
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80
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FLT3-ITD up-regulates MCL-1 to promote survival of stem cells in acute myeloid leukemia via FLT3-ITD-specific STAT5 activation. Blood 2009; 114:5034-43. [PMID: 19808698 DOI: 10.1182/blood-2008-12-196055] [Citation(s) in RCA: 191] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Myeloid cell leukemia-1 (MCL-1) is an essential survival factor for hematopoiesis. In humans, hematopoietic stem cells (HSCs) express MCL-1 at the highest level in response to FMS-like tyrosine kinase-3 (FLT3) signaling. We here show that this FLT3-dependent stem cell maintenance system also plays a critical role in survival of leukemic stem cells (LSCs) in acute myeloid leukemia (AML). The CD34(+)CD38(-) LSC fraction expresses high levels of FLT3 as well as MCL-1, even compared with normal HSCs. Treatment with FLT3 ligand induced further MCL-1 up-regulation in LSCs in all AML cases tested. Interestingly, the group of samples expressing the highest levels of MCL-1 constituted AML with FLT3-internal tandem duplications (ITD). In FLT3-ITD AML cell lines, cells expressed a high level of MCL-1, and an inhibition of MCL-1 induced their apoptotic cell death. A tyrosine kinase inhibitor suppressed MCL-1 expression, and induced apoptosis that was reversed by the enforced MCL-1 expression. Finally, transduction of FLT3-ITD into HSCs strongly activated MCL-1 expression through its signal transducer and activator of transcription 5 (STAT5)-docking domains. This effect was completely abrogated when STAT5 activation was blocked. Thus, the acquisition of FLT3-ITD ensures LSC survival by up-regulating MCL-1 via constitutive STAT5 activation that is independent of wild-type FLT3 signaling.
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81
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Hahn CK, Berchuck JE, Ross KN, Kakoza RM, Clauser K, Schinzel AC, Ross L, Galinsky I, Davis TN, Silver SJ, Root DE, Stone RM, DeAngelo DJ, Carroll M, Hahn WC, Carr SA, Golub TR, Kung AL, Stegmaier K. Proteomic and genetic approaches identify Syk as an AML target. Cancer Cell 2009; 16:281-94. [PMID: 19800574 PMCID: PMC2803063 DOI: 10.1016/j.ccr.2009.08.018] [Citation(s) in RCA: 127] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/28/2009] [Revised: 07/08/2009] [Accepted: 08/19/2009] [Indexed: 12/18/2022]
Abstract
Cell-based screening can facilitate the rapid identification of compounds inducing complex cellular phenotypes. Advancing a compound toward the clinic, however, generally requires the identification of precise mechanisms of action. We previously found that epidermal growth factor receptor (EGFR) inhibitors induce acute myeloid leukemia (AML) differentiation via a non-EGFR mechanism. In this report, we integrated proteomic and RNAi-based strategies to identify their off-target, anti-AML mechanism. These orthogonal approaches identified Syk as a target in AML. Genetic and pharmacological inactivation of Syk with a drug in clinical trial for other indications promoted differentiation of AML cells and attenuated leukemia growth in vivo. These results demonstrate the power of integrating diverse chemical, proteomic, and genomic screening approaches to identify therapeutic strategies for cancer.
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MESH Headings
- Aminopyridines
- Animals
- Antineoplastic Agents/pharmacology
- Cell Differentiation/drug effects
- Cell Proliferation/drug effects
- Cell Survival/drug effects
- Dose-Response Relationship, Drug
- Gefitinib
- Gene Expression Profiling
- Gene Expression Regulation, Leukemic
- Genomics/methods
- HL-60 Cells
- Humans
- Inhibitory Concentration 50
- Intracellular Signaling Peptides and Proteins/antagonists & inhibitors
- Intracellular Signaling Peptides and Proteins/genetics
- Intracellular Signaling Peptides and Proteins/metabolism
- Leukemia, Myeloid, Acute/drug therapy
- Leukemia, Myeloid, Acute/genetics
- Leukemia, Myeloid, Acute/metabolism
- Leukemia, Myeloid, Acute/pathology
- Male
- Mice
- Mice, Inbred C57BL
- Mice, Inbred NOD
- Mice, SCID
- Morpholines
- Oxazines/pharmacology
- Phosphorylation
- Protein Kinase Inhibitors/pharmacology
- Protein-Tyrosine Kinases/antagonists & inhibitors
- Protein-Tyrosine Kinases/genetics
- Protein-Tyrosine Kinases/metabolism
- Proteomics/methods
- Pyridines/pharmacology
- Pyrimidines
- Quinazolines/pharmacology
- RNA Interference
- Syk Kinase
- Tandem Mass Spectrometry
- Time Factors
- Tumor Cells, Cultured
- Tyrosine
- U937 Cells
- Xenograft Model Antitumor Assays
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Affiliation(s)
- Cynthia K Hahn
- Department of Pediatric Oncology, Dana-Farber Cancer Institute and Children's Hospital Boston, Harvard Medical School, Boston, MA 02115, USA
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82
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Ono R, Kumagai H, Nakajima H, Hishiya A, Taki T, Horikawa K, Takatsu K, Satoh T, Hayashi Y, Kitamura T, Nosaka T. Mixed-lineage-leukemia (MLL) fusion protein collaborates with Ras to induce acute leukemia through aberrant Hox expression and Raf activation. Leukemia 2009; 23:2197-209. [PMID: 19710696 DOI: 10.1038/leu.2009.177] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Mixed-lineage-leukemia (MLL) fusion oncogenes are closely involved in infant acute leukemia, which is frequently accompanied by mutations or overexpression of FMS-like receptor tyrosine kinase 3 (FLT3). Earlier studies have shown that MLL fusion proteins induced acute leukemia together with another mutation, such as an FLT3 mutant, in mouse models. However, little has hitherto been elucidated regarding the molecular mechanism of the cooperativity in leukemogenesis. Using murine model systems of the MLL-fusion-mediated leukemogenesis leading to oncogenic transformation in vitro and acute leukemia in vivo, this study characterized the molecular network in the cooperative leukemogenesis. This research revealed that MLL fusion proteins cooperated with activation of Ras in vivo, which was substitutable for Raf in vitro, synergistically, but not with activation of signal transducer and activator of transcription 5 (STAT5), to induce acute leukemia in vivo as well as oncogenic transformation in vitro. Furthermore, Hoxa9, one of the MLL-targeted critical molecules, and activation of Ras in vivo, which was replaceable with Raf in vitro, were identified as fundamental components sufficient for mimicking MLL-fusion-mediated leukemogenesis. These findings suggest that the molecular crosstalk between aberrant expression of Hox molecule(s) and activated Raf may have a key role in the MLL-fusion-mediated-leukemogenesis, and may thus help develop the novel molecularly targeted therapy against MLL-related leukemia.
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Affiliation(s)
- R Ono
- Division of Hematopoietic Factors, The Institute of Medical Science, The University of Tokyo, Tokyo, Japan
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83
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Abstract
Treatment of hematologic malignancies is evolving from a uniform approach to targeted therapies directed at the underlying molecular abnormalities of disease. The mixed lineage leukemia (MLL) proto-oncogene is a recurrent site of genetic rearrangements in acute leukemias; and since its discovery in 1992, many advances have been made in understanding its role in leukemogenesis. A variety of MLL translocation partners have been described, and detailed structure/function studies have identified functional domains that are required for transformation. Proteins associated with the MLL core complex or its fusion partners have been isolated and characterized for their critical roles in leukemia pathogenesis. Downstream mediators of MLL transcriptional regulation and multiple collaborating signaling pathways have been described and characterized. These advances in our understanding of MLL-related leukemogenesis provide a foundation for ongoing and future efforts to develop novel therapeutic strategies that will hopefully result in better treatment outcomes.
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84
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RAS oncogene suppression induces apoptosis followed by more differentiated and less myelosuppressive disease upon relapse of acute myeloid leukemia. Blood 2008; 113:1086-96. [PMID: 18952898 DOI: 10.1182/blood-2008-01-132316] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
To study the oncogenic role of the NRAS oncogene (NRAS(G12V)) in the context of acute myeloid leukemia (AML), we used a Vav promoter-tetracycline transactivator (Vav-tTA)-driven repressible TRE-NRAS(G12V) transgene system in Mll-AF9 knock-in mice developing AML. Conditional repression of NRAS(G12V) expression greatly reduced peripheral white blood cell (WBC) counts in leukemia recipient mice and induced apoptosis in the transplanted AML cells correlated with reduced Ras/Erk signaling. After marked decrease of AML blast cells, myeloproliferative disease (MPD)-like AML relapsed characterized by cells that did not express NRAS(G12V). In comparison with primary AML, the MPD-like AML showed significantly reduced aggressiveness, reduced myelosuppression, and a more differentiated phenotype. We conclude that, in AML induced by an Mll-AF9 transgene, NRAS(G12V) expression contributes to acute leukemia maintenance by suppressing apoptosis and reducing differentiation of leukemia cells. Moreover, NRAS(G12V) oncogene has a cell nonautonomous role in suppressing erythropoiesis that results in the MPD-like AML show significantly reduced ability to induce anemia. Our results imply that targeting NRAS or RAS oncogene-activated pathways is a good therapeutic strategy for AML and attenuating aggressiveness of relapsed AML.
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85
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Wei J, Wunderlich M, Fox C, Alvarez S, Cigudosa JC, Wilhelm JS, Zheng Y, Cancelas JA, Gu Y, Jansen M, DiMartino JF, Mulloy JC. Microenvironment determines lineage fate in a human model of MLL-AF9 leukemia. Cancer Cell 2008; 13:483-95. [PMID: 18538732 PMCID: PMC2486365 DOI: 10.1016/j.ccr.2008.04.020] [Citation(s) in RCA: 245] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/30/2007] [Revised: 12/26/2007] [Accepted: 04/22/2008] [Indexed: 12/12/2022]
Abstract
Faithful modeling of mixed-lineage leukemia in murine cells has been difficult to achieve. We show that expression of MLL-AF9 in human CD34+ cells induces acute myeloid, lymphoid, or mixed-lineage leukemia in immunodeficient mice. Some leukemia stem cells (LSC) were multipotent and could be lineage directed by altering either the growth factors or the recipient strain of mouse, highlighting the importance of microenvironmental cues. Other LSC were strictly lineage committed, demonstrating the heterogeneity of the stem cell compartment in MLL disease. Targeting the Rac signaling pathway by pharmacologic or genetic means resulted in rapid and specific apoptosis of MLL-AF9 cells, suggesting that the Rac signaling pathway may be a valid therapeutic target in MLL-rearranged AML.
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MESH Headings
- Aneuploidy
- Animals
- Antigens, CD34/analysis
- Apoptosis
- Cell Culture Techniques
- Cell Line, Transformed
- Cell Lineage
- Cell Proliferation
- Cell Transformation, Neoplastic/genetics
- Cell Transformation, Neoplastic/metabolism
- Cell Transformation, Neoplastic/pathology
- Chromosomes, Human, Pair 11
- Environment
- Fetal Blood/immunology
- Fetal Blood/metabolism
- Fetal Stem Cells/immunology
- Fetal Stem Cells/metabolism
- Fetal Stem Cells/pathology
- Gene Expression Profiling
- Gene Expression Regulation, Neoplastic
- Genotype
- Humans
- Intercellular Signaling Peptides and Proteins/metabolism
- Leukemia, Experimental/metabolism
- Leukemia, Experimental/pathology
- Leukemia, Myeloid, Acute/genetics
- Leukemia, Myeloid, Acute/metabolism
- Leukemia, Myeloid, Acute/pathology
- Mice
- Mice, Inbred NOD
- Mice, SCID
- Multipotent Stem Cells/immunology
- Multipotent Stem Cells/metabolism
- Multipotent Stem Cells/pathology
- Myeloid-Lymphoid Leukemia Protein/genetics
- Myeloid-Lymphoid Leukemia Protein/metabolism
- Neoplastic Stem Cells/immunology
- Neoplastic Stem Cells/metabolism
- Neoplastic Stem Cells/pathology
- Oncogene Proteins, Fusion/genetics
- Oncogene Proteins, Fusion/metabolism
- Phenotype
- Precursor Cell Lymphoblastic Leukemia-Lymphoma/genetics
- Precursor Cell Lymphoblastic Leukemia-Lymphoma/metabolism
- Precursor Cell Lymphoblastic Leukemia-Lymphoma/pathology
- Signal Transduction
- Species Specificity
- Stem Cell Transplantation
- Time Factors
- Transduction, Genetic
- Translocation, Genetic
- rac GTP-Binding Proteins/genetics
- rac GTP-Binding Proteins/metabolism
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Affiliation(s)
- Junping Wei
- Division of Experimental Hematology, Cincinnati Children's Hospital Medical Center, University of Cincinnati College of Medicine, Cincinnati OH
| | - Mark Wunderlich
- Division of Experimental Hematology, Cincinnati Children's Hospital Medical Center, University of Cincinnati College of Medicine, Cincinnati OH
| | - Catherine Fox
- Division of Experimental Hematology, Cincinnati Children's Hospital Medical Center, University of Cincinnati College of Medicine, Cincinnati OH
| | - Sara Alvarez
- Molecular Cytogenetics Group, Centro Nacional de Investigaciones Oncologicas, Madrid Spain
| | - Juan C. Cigudosa
- Molecular Cytogenetics Group, Centro Nacional de Investigaciones Oncologicas, Madrid Spain
| | - Jamie S. Wilhelm
- Division of Experimental Hematology, Cincinnati Children's Hospital Medical Center, University of Cincinnati College of Medicine, Cincinnati OH
| | - Yi Zheng
- Division of Experimental Hematology, Cincinnati Children's Hospital Medical Center, University of Cincinnati College of Medicine, Cincinnati OH
| | - Jose A. Cancelas
- Division of Experimental Hematology, Cincinnati Children's Hospital Medical Center, University of Cincinnati College of Medicine, Cincinnati OH
- Hoxworth Blood Center, University of Cincinnati,, Cincinnati OH
| | - Yi Gu
- Division of Experimental Hematology, Cincinnati Children's Hospital Medical Center, University of Cincinnati College of Medicine, Cincinnati OH
| | - Michael Jansen
- Division of Experimental Hematology, Cincinnati Children's Hospital Medical Center, University of Cincinnati College of Medicine, Cincinnati OH
- Division of Biomedical Informatics, Cincinnati Children's Hospital Medical Center, University of Cincinnati College of Medicine, Cincinnati OH
| | - Jorge F. DiMartino
- Division of Hematology Oncology, Cincinnati Children's Hospital Medical Center, University of Cincinnati College of Medicine, Cincinnati OH
| | - James C. Mulloy
- Division of Experimental Hematology, Cincinnati Children's Hospital Medical Center, University of Cincinnati College of Medicine, Cincinnati OH
- Corresponding author: James C. Mulloy, CCHMC, 3333 Burnet Avenue, ML 7013, Cincinnati OH 45226 phone (513)-636-1844, fax (513)-404-3768,
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