1
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Ye Y, Yang X, Li F, Liu W, Zhang W, Huang Z. c-myb is involved in CML progression and is a therapeutic target in the zebrafish CML model. Animal Model Exp Med 2024; 7:136-144. [PMID: 36300552 PMCID: PMC11079146 DOI: 10.1002/ame2.12282] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Accepted: 09/27/2022] [Indexed: 02/18/2024] Open
Abstract
BACKGROUND Despite the success of tyrosine kinase inhibitors in chronic myeloid leukemia (CML) therapy, CML still faces the challenges of drug resistance and progression to blast crisis. Twenty-five percent of patients have imatinib resistance and treatment difficulties due to heterogeneity after progression, but little is known about the mechanism. A key transcription factor in hematopoiesis, MYB, has been reported to increase abnormally in several types of aggressive blood disorders including CML. METHODS This study used a zebrafish model to explore the relationship between BCR/ABL1 and c-myb in CML progression. A CML zebrafish model was crossed with a c-myb hyperactivity transgenic line. RESULTS It was found that both exogenous BCR/ABL1 and c-myb could up-regulate the expression of neutrophil-related genes. More seriously, neutrophil accumulation was observed when BCR/ABL1 was combined with c-myb overexpression. Further studies showed that c-myb may be one of the downstream targets of BCR/ABL1 and the effect of BCR/ABL1 on neutrophils was c-myb dependent. Taking advantage of this inheritable in vivo model, it was shown that a combination of imatinib and flavopiridol, a cyclin-dependent kinase inhibitor targeting MYB, could more effectively alleviate the aggressive phenotype of the double transgene line. CONCLUSION In summary, this study suggests that c-myb acts downstream of BCR/ABL1 and is involved in CML progression and is therefore a risk factor and a valuable target for the treatment of CML progression. The model used in the study could be helpful in high-throughput drug screening in CML transformation.
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MESH Headings
- Animals
- Animals, Genetically Modified
- Antineoplastic Agents/pharmacology
- Antineoplastic Agents/therapeutic use
- Disease Models, Animal
- Disease Progression
- Flavonoids/pharmacology
- Flavonoids/therapeutic use
- Fusion Proteins, bcr-abl/genetics
- Fusion Proteins, bcr-abl/metabolism
- Imatinib Mesylate/pharmacology
- Imatinib Mesylate/therapeutic use
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/drug therapy
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/genetics
- Neutrophils/drug effects
- Neutrophils/metabolism
- Piperidines/pharmacology
- Piperidines/therapeutic use
- Protein Kinase Inhibitors/pharmacology
- Protein Kinase Inhibitors/therapeutic use
- Proto-Oncogene Proteins c-myb/genetics
- Proto-Oncogene Proteins c-myb/metabolism
- Zebrafish
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Affiliation(s)
- Yin Ye
- Division of Cell, Developmental and Integrative Biology, School of MedicineSouth China University of TechnologyGuangzhouChina
| | - Xiaojun Yang
- Division of Cell, Developmental and Integrative Biology, School of MedicineSouth China University of TechnologyGuangzhouChina
| | - Feifei Li
- Division of Cell, Developmental and Integrative Biology, School of MedicineSouth China University of TechnologyGuangzhouChina
| | - Wei Liu
- Division of Cell, Developmental and Integrative Biology, School of MedicineSouth China University of TechnologyGuangzhouChina
| | - Wenqing Zhang
- Division of Cell, Developmental and Integrative Biology, School of MedicineSouth China University of TechnologyGuangzhouChina
| | - Zhibin Huang
- Division of Cell, Developmental and Integrative Biology, School of MedicineSouth China University of TechnologyGuangzhouChina
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2
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Almeida A, T'Sas S, Pagliaro L, Fijalkowski I, Sleeckx W, Van Steenberge H, Zamponi R, Lintermans B, Van Loocke W, Palhais B, Reekmans A, Bardelli V, Demoen L, Reunes L, Deforce D, Van Nieuwerburgh F, Kentsis A, Ntziachristos P, Van Roy N, De Moerloose B, Mecucci C, La Starza R, Roti G, Goossens S, Van Vlierberghe P, Pieters T. Myb overexpression synergizes with the loss of Pten and is a dependency factor and therapeutic target in T-cell lymphoblastic leukemia. Hemasphere 2024; 8:e51. [PMID: 38463444 PMCID: PMC10924755 DOI: 10.1002/hem3.51] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2023] [Accepted: 01/28/2024] [Indexed: 03/12/2024] Open
Abstract
T-lineage acute lymphoblastic leukemia (T-ALL) is an aggressive hematological malignancy that accounts for 10%-15% of pediatric and 25% of adult ALL cases. Although the prognosis of T-ALL has improved over time, the outcome of T-ALL patients with primary resistant or relapsed leukemia remains poor. Therefore, further progress in the treatment of T-ALL requires a better understanding of its biology and the development of more effective precision oncologic therapies. The proto-oncogene MYB is highly expressed in diverse hematologic malignancies, including T-ALLs with genomic aberrations that further potentiate its expression and activity. Previous studies have associated MYB with a malignant role in the pathogenesis of several cancers. However, its role in the induction and maintenance of T-ALL remains relatively poorly understood. In this study, we found that an increased copy number of MYB is associated with higher MYB expression levels, and might be associated with inferior event-free survival of pediatric T-ALL patients. Using our previously described conditional Myb overexpression mice, we generated two distinct MYB-driven T-ALL mouse models. We demonstrated that the overexpression of Myb synergizes with Pten deletion but not with the overexpression of Lmo2 to accelerate the development of T-cell lymphoblastic leukemias. We also showed that MYB is a dependency factor in T-ALL since RNA interference of Myb blocked cell cycle progression and induced apoptosis in both human and murine T-ALL cell lines. Finally, we provide preclinical evidence that targeting the transcriptional activity of MYB can be a useful therapeutic strategy for the treatment of T-ALL.
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Affiliation(s)
- André Almeida
- Normal and Malignant Hematopoiesis Lab, Department of Biomolecular MedicineGhent UniversityGhentBelgium
- Cancer Research Institute Ghent (CRIG)GhentBelgium
| | - Sara T'Sas
- Normal and Malignant Hematopoiesis Lab, Department of Biomolecular MedicineGhent UniversityGhentBelgium
- Cancer Research Institute Ghent (CRIG)GhentBelgium
- Unit for Translational Research in Oncology, Department of Diagnostic SciencesGhent UniversityGhentBelgium
| | - Luca Pagliaro
- Normal and Malignant Hematopoiesis Lab, Department of Biomolecular MedicineGhent UniversityGhentBelgium
- Cancer Research Institute Ghent (CRIG)GhentBelgium
- Department of Medicine and SurgeryUniversity of ParmaParmaItaly
| | - Igor Fijalkowski
- Cancer Research Institute Ghent (CRIG)GhentBelgium
- Leukemia Therapy Resistance Laboratory and Center for Medical Genetics, Department of Biomolecular MedicineGhent UniversityGhentBelgium
| | - Wouter Sleeckx
- Cancer Research Institute Ghent (CRIG)GhentBelgium
- Unit for Translational Research in Oncology, Department of Diagnostic SciencesGhent UniversityGhentBelgium
| | - Hannah Van Steenberge
- Cancer Research Institute Ghent (CRIG)GhentBelgium
- Unit for Translational Research in Oncology, Department of Diagnostic SciencesGhent UniversityGhentBelgium
| | | | - Béatrice Lintermans
- Normal and Malignant Hematopoiesis Lab, Department of Biomolecular MedicineGhent UniversityGhentBelgium
- Cancer Research Institute Ghent (CRIG)GhentBelgium
| | - Wouter Van Loocke
- Normal and Malignant Hematopoiesis Lab, Department of Biomolecular MedicineGhent UniversityGhentBelgium
- Cancer Research Institute Ghent (CRIG)GhentBelgium
| | - Bruno Palhais
- Normal and Malignant Hematopoiesis Lab, Department of Biomolecular MedicineGhent UniversityGhentBelgium
- Cancer Research Institute Ghent (CRIG)GhentBelgium
- Leukemia Therapy Resistance Laboratory and Center for Medical Genetics, Department of Biomolecular MedicineGhent UniversityGhentBelgium
| | - Alexandra Reekmans
- Normal and Malignant Hematopoiesis Lab, Department of Biomolecular MedicineGhent UniversityGhentBelgium
- Unit for Translational Research in Oncology, Department of Diagnostic SciencesGhent UniversityGhentBelgium
| | - Valentina Bardelli
- Institute of Hematology and Center for Hemato‐Oncology ResearchUniversity of Perugia and S.M. Misericordia HospitalPerugiaItaly
| | - Lisa Demoen
- Normal and Malignant Hematopoiesis Lab, Department of Biomolecular MedicineGhent UniversityGhentBelgium
- Cancer Research Institute Ghent (CRIG)GhentBelgium
| | - Lindy Reunes
- Normal and Malignant Hematopoiesis Lab, Department of Biomolecular MedicineGhent UniversityGhentBelgium
- Cancer Research Institute Ghent (CRIG)GhentBelgium
- Leukemia Therapy Resistance Laboratory and Center for Medical Genetics, Department of Biomolecular MedicineGhent UniversityGhentBelgium
| | - Dieter Deforce
- Laboratory of Pharmaceutical BiotechnologyGhent UniversityGhentBelgium
| | | | - Alex Kentsis
- Tow Center for Developmental Oncology, Sloan Kettering Institute and Department of PediatricsMemorial Sloan Kettering Cancer CenterNew YorkNew YorkUSA
| | - Panagiotis Ntziachristos
- Cancer Research Institute Ghent (CRIG)GhentBelgium
- Leukemia Therapy Resistance Laboratory and Center for Medical Genetics, Department of Biomolecular MedicineGhent UniversityGhentBelgium
| | - Nadine Van Roy
- Cancer Research Institute Ghent (CRIG)GhentBelgium
- Lab for Translational Oncogenomics and Bioinformatics, Department of Biomolecular MedicineGhent UniversityGhentBelgium
- Pediatric Precision Oncology Lab, Department of Biomolecular MedicineGhent UniversityGhentBelgium
| | - Barbara De Moerloose
- Cancer Research Institute Ghent (CRIG)GhentBelgium
- Department of Pediatric Hematology‐OncologyGhent University HospitalGhentBelgium
| | - Cristina Mecucci
- Institute of Hematology and Center for Hemato‐Oncology ResearchUniversity of Perugia and S.M. Misericordia HospitalPerugiaItaly
| | - Roberta La Starza
- Institute of Hematology and Center for Hemato‐Oncology ResearchUniversity of Perugia and S.M. Misericordia HospitalPerugiaItaly
| | - Giovanni Roti
- Department of Medicine and SurgeryUniversity of ParmaParmaItaly
| | - Steven Goossens
- Cancer Research Institute Ghent (CRIG)GhentBelgium
- Unit for Translational Research in Oncology, Department of Diagnostic SciencesGhent UniversityGhentBelgium
| | - Pieter Van Vlierberghe
- Normal and Malignant Hematopoiesis Lab, Department of Biomolecular MedicineGhent UniversityGhentBelgium
- Cancer Research Institute Ghent (CRIG)GhentBelgium
| | - Tim Pieters
- Normal and Malignant Hematopoiesis Lab, Department of Biomolecular MedicineGhent UniversityGhentBelgium
- Cancer Research Institute Ghent (CRIG)GhentBelgium
- Unit for Translational Research in Oncology, Department of Diagnostic SciencesGhent UniversityGhentBelgium
- Leukemia Therapy Resistance Laboratory and Center for Medical Genetics, Department of Biomolecular MedicineGhent UniversityGhentBelgium
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3
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Wilde L, Porazzi P, Trotta R, De Dominici M, Palmisiano N, Keiffer G, Rancani K, Yingling K, Calabretta B, Kasner M. A phase I study of the combination of palbociclib and dexamethasone for the treatment of relapsed or refractory B-cell acute lymphoblastic leukemia. Leuk Res 2023; 129:107075. [PMID: 37079999 DOI: 10.1016/j.leukres.2023.107075] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Revised: 03/20/2023] [Accepted: 04/05/2023] [Indexed: 04/22/2023]
Abstract
PURPOSE Despite advances in the treatment of B-cell acute lymphoblastic leukemia (B-ALL), outcomes for relapsed/refractory (R/R) disease remain poor. Preclinical studies suggest that the combination of the CDK4/6 inhibitor palbociclib and dexamethasone may be effective in targeting leukemic cell growth. We conducted a phase I study of escalating doses of palbociclib in combination with dexamethasone in adults with R/R B-ALL. METHODS Cycle 1 consisted of single agent palbociclib given for 7 days and continued for 28 additional days in combination with dexamethasone 20 mg daily. Palbociclib dosing began at 100 mg daily. Patients with a response were eligible for maintenance consisting of 1 week of palbociclib plus dexamethasone (20 mg daily × 2 days, 16 mg daily × 2 days, 12 mg daily × 2 days, 6 mg daily × 1 day), followed by 3 weeks of palbociclib alone. Safety, efficacy, and the expression of phospho-RB and c-MYB/BCL-2 were measured. CONCLUSIONS Seven patients were treated on study before it was closed early due to slow accrual. No dose limiting toxicities were identified. One patient had a complete response with incomplete hematologic recovery, suggesting possible efficacy of the treatment. Reduction in CD34+ cells, p-RB, c-MYB, and BCL-2 expression also suggested on-target therapy effects.
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Affiliation(s)
- Lindsay Wilde
- Department of Medical Oncology, Sidney Kimmel Cancer Center, Thomas Jefferson University Hospital, Philadelphia, PA, United States.
| | - Patrizia Porazzi
- Division of Hematology and Oncology and Center for Cellular Immunotherapies, University of Pennsylvania, Philadelphia, PA, United States
| | - Rossana Trotta
- Department of Cancer Biology, Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA, United States
| | - Marco De Dominici
- Department of Biochemistry and Molecular Genetics, University of Colorado, Denver, CO, United States
| | - Neil Palmisiano
- Department of Medical Oncology, Sidney Kimmel Cancer Center, Thomas Jefferson University Hospital, Philadelphia, PA, United States
| | - Gina Keiffer
- Department of Medical Oncology, Sidney Kimmel Cancer Center, Thomas Jefferson University Hospital, Philadelphia, PA, United States
| | - Kaitlin Rancani
- Department of Medical Oncology, Sidney Kimmel Cancer Center, Thomas Jefferson University Hospital, Philadelphia, PA, United States
| | - Kathryn Yingling
- Department of Medical Oncology, Sidney Kimmel Cancer Center, Thomas Jefferson University Hospital, Philadelphia, PA, United States
| | - Bruno Calabretta
- Department of Cancer Biology, Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA, United States
| | - Margaret Kasner
- Department of Medical Oncology, Sidney Kimmel Cancer Center, Thomas Jefferson University Hospital, Philadelphia, PA, United States
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4
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Klempnauer KH. C/EBPβ cooperates with MYB to maintain the oncogenic program of AML cells. Oncotarget 2023; 14:174-177. [PMID: 36913305 PMCID: PMC10010626 DOI: 10.18632/oncotarget.28377] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Indexed: 03/13/2023] Open
Abstract
Studies on the role of transcription factor MYB in acute myeloid leukemia (AML) have identified MYB as a key regulator of a transcriptional program for self-renewal of AML cells. Recent work summarized here has now highlighted the CCAAT-box/enhancer binding protein beta (C/EBPβ) as an essential factor and potential therapeutic target that cooperates with MYB and coactivator p300 in the maintenance of the leukemic cells.
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Affiliation(s)
- Karl-Heinz Klempnauer
- Correspondence to:Karl-Heinz Klempnauer, Institute for Biochemistry, Westfälische-Wilhelms-Universität, Muenster D-48149, Germany email
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5
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Köhler LF, Reich S, Yusenko M, Klempnauer KH, Shaikh AH, Ahmed K, Begemann G, Schobert R, Biersack B. A New Naphthopyran Derivative Combines c-Myb Inhibition, Microtubule-Targeting Effects, and Antiangiogenic Properties. ACS Med Chem Lett 2022; 13:1783-1790. [PMID: 36385941 PMCID: PMC9661705 DOI: 10.1021/acsmedchemlett.2c00403] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2022] [Accepted: 10/28/2022] [Indexed: 11/28/2022] Open
Abstract
Based on the promising c-Myb inhibitor 1b, a series of 2-amino-4-aryl-4H-naphtho[1,2-b]pyran-3-carbonitriles (1a, 2a-q, 3a-g) were repurposed or newly synthesized via a three-component reaction of 1-naphthol, and various aryl aldehydes and malononitrile and screened for their c-Myb inhibitory activities. 1b also served as a lead compound for seven new naphthopyran derivatives (3a-f), which were cytotoxic with nanomolar IC50 values, to inhibit the polymerization of tubulin, and to destabilize microtubules in living cells. Especially, the alkyne 3f, originally made for intracellular localization studies using click chemistry, showed an overall high activity in all assays performed. A strong G2/M cell cycle arrest was detected, which resulted in a distinct increase in sub-G1 cells through the induction of effector caspases 3 and 7. Inhibition of angiogenesis was confirmed in vitro and in vivo. In summary, 3f was found to be a pleiotropic compound with high selectivity for cancer cells, combining c-Myb inhibitory, microtubule destabilizing, and antiangiogenic effects.
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Affiliation(s)
- Leonhard
H. F. Köhler
- Organic
Chemistry Laboratory, University of Bayreuth, Universitätsstrasse 30, 95440 Bayreuth, Germany
| | - Sebastian Reich
- Organic
Chemistry Laboratory, University of Bayreuth, Universitätsstrasse 30, 95440 Bayreuth, Germany
| | - Maria Yusenko
- Institute
for Biochemistry, Westfälische-Wilhelms-Universität, Wilhelm-Klemm-Strasse 2, 48149 Münster, Germany
| | - Karl-Heinz Klempnauer
- Institute
for Biochemistry, Westfälische-Wilhelms-Universität, Wilhelm-Klemm-Strasse 2, 48149 Münster, Germany
| | - Amin H. Shaikh
- Department
of Chemistry & Post Graduate Research Center, Abeda Inamdar Senior College, Camp, Pune 411001, India
| | - Khursheed Ahmed
- Department
of Chemistry & Post Graduate Research Center, Abeda Inamdar Senior College, Camp, Pune 411001, India
| | - Gerrit Begemann
- Developmental
Biology, University of Bayreuth, Universitätsstrasse 30, 95440 Bayreuth, Germany
| | - Rainer Schobert
- Organic
Chemistry Laboratory, University of Bayreuth, Universitätsstrasse 30, 95440 Bayreuth, Germany
| | - Bernhard Biersack
- Organic
Chemistry Laboratory, University of Bayreuth, Universitätsstrasse 30, 95440 Bayreuth, Germany
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6
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Identification of a c-MYB-directed therapeutic for acute myeloid leukemia. Leukemia 2022; 36:1541-1549. [PMID: 35368048 PMCID: PMC9162920 DOI: 10.1038/s41375-022-01554-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2021] [Revised: 03/07/2022] [Accepted: 03/21/2022] [Indexed: 11/27/2022]
Abstract
A significant proportion of patients suffering from acute myeloid leukemia (AML) cannot be cured by conventional chemotherapy, relapsed disease being a common problem. Molecular targeting of essential oncogenic mediators is an attractive approach to improving outcomes for this disease. The hematopoietic transcription factor c-MYB has been revealed as a central component of complexes maintaining aberrant gene expression programs in AML. We have previously screened the Connectivity Map database to identify mebendazole as an anti-AML therapeutic targeting c-MYB. In the present study we demonstrate that another hit from this screen, the steroidal lactone withaferin A (WFA), induces rapid ablation of c-MYB protein and consequent inhibition of c-MYB target gene expression, loss of leukemia cell viability, reduced colony formation and impaired disease progression. Although WFA has been reported to have pleiotropic anti-cancer effects, we demonstrate that its anti-AML activity depends on c-MYB modulation and can be partially reversed by a stabilized c-MYB mutant. c-MYB ablation results from disrupted HSP/HSC70 chaperone protein homeostasis in leukemia cells following induction of proteotoxicity and the unfolded protein response by WFA. The widespread use of WFA in traditional medicines throughout the world indicates that it represents a promising candidate for repurposing into AML therapy.
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7
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Porazzi P, De Dominici M, Salvino J, Calabretta B. Targeting the CDK6 Dependence of Ph+ Acute Lymphoblastic Leukemia. Genes (Basel) 2021; 12:genes12091355. [PMID: 34573335 PMCID: PMC8467343 DOI: 10.3390/genes12091355] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Revised: 08/27/2021] [Accepted: 08/27/2021] [Indexed: 12/13/2022] Open
Abstract
Ph+ ALL is a poor-prognosis leukemia subtype driven by the BCR-ABL1 oncogene, either the p190- or the p210-BCR/ABL isoform in a 70:30 ratio. Tyrosine Kinase inhibitors (TKIs) are the drugs of choice in the therapy of Ph+ ALL. In combination with standard chemotherapy, TKIs have markedly improved the outcome of Ph+ ALL, in particular if this treatment is followed by bone marrow transplantation. However, resistance to TKIs develops with high frequency, causing leukemia relapse that results in <5-year overall survival. Thus, new therapies are needed to address relapsed/TKI-resistant Ph+ ALL. We have shown that expression of cell cycle regulatory kinase CDK6, but not of the highly related CDK4 kinase, is required for the proliferation and survival of Ph+ ALL cells. Comparison of leukemia suppression induced by treatment with the clinically-approved dual CDK4/6 inhibitor palbociclib versus CDK6 silencing revealed that the latter treatment was markedly more effective, probably reflecting inhibition of CDK6 kinase-independent effects. Thus, we developed CDK4/6-targeted proteolysis-targeting chimeras (PROTACs) that preferentially degrade CDK6 over CDK4. One compound termed PROTAC YX-2-107, which degrades CDK6 by recruiting the Cereblon ubiquitin ligase, markedly suppressed leukemia burden in mice injected with de novo or TKI-resistant Ph+ ALL. The effect of PROTAC YX-2-107 was comparable or superior to that of palbociclib. The development of CDK6-selective PROTACs represents an effective strategy to exploit the “CDK6 dependence” of Ph+ ALL cells while sparing a high proportion of normal hematopoietic progenitors that depend on both CDK6 and CDK6 for their survival. In combination with other agents, CDK6-selective PROTACs may be valuable components of chemotherapy-free protocols for the therapy of Ph+ ALL and other CDK6-dependent hematological malignancies.
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Affiliation(s)
- Patrizia Porazzi
- Department of Cancer Biology, Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA 19107, USA;
- Correspondence:
| | - Marco De Dominici
- Department of Biochemistry and Molecular Genetics, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA;
| | | | - Bruno Calabretta
- Department of Cancer Biology, Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA 19107, USA;
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8
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Dúcka M, Kučeríková M, Trčka F, Červinka J, Biglieri E, Šmarda J, Borsig L, Beneš P, Knopfová L. c-Myb interferes with inflammatory IL1α-NF-κB pathway in breast cancer cells. Neoplasia 2021; 23:326-336. [PMID: 33621853 PMCID: PMC7905261 DOI: 10.1016/j.neo.2021.01.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Revised: 01/12/2021] [Accepted: 01/20/2021] [Indexed: 12/14/2022] Open
Abstract
The transcription factor c-Myb can be involved in the activation of many genes with protumorigenic function; however, its role in breast cancer (BC) development is still under discussion. c-Myb is considered as a tumor-promoting factor in the early phases of BC, on the other hand, its expression in BC patients relates to a good prognosis. Previously, we have shown that c-Myb controls the capacity of BC cells to form spontaneous lung metastasis. Reduced seeding of BC cells to the lungs is linked to high expression of c-Myb and a decline in expression of a specific set of inflammatory genes. Here, we unraveled a c-Myb-IL1α-NF-κB signaling axis that takes place in tumor cells. We report that an overexpression of c-Myb interfered with the activity of NF-κB in several BC cell lines. We identified IL1α to be essential for this interference since it was abrogated in the IL1α-deficient cells. Overexpression of IL1α, as well as addition of recombinant IL1α protein, activated NF-κB signaling and restored expression of the inflammatory signature genes suppressed by c-Myb. The endogenous levels of c-Myb negatively correlated with IL1α on both transcriptional and protein levels across BC cell lines. We concluded that inhibition of IL1α expression by c-Myb reduces NF-κB activity and disconnects the inflammatory circuit, a potentially targetable mechanism to mimic the antimetastatic effect of c-Myb with therapeutic perspective.
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Affiliation(s)
- Monika Dúcka
- Department of Experimental Biology, Faculty of Science, Masaryk University, Brno, Czech Republic; International Clinical Research Center, Center for Biological and Cellular Engineering, St. Anne's University Hospital, Brno, Czech Republic
| | - Martina Kučeríková
- Department of Experimental Biology, Faculty of Science, Masaryk University, Brno, Czech Republic
| | - Filip Trčka
- Department of Experimental Biology, Faculty of Science, Masaryk University, Brno, Czech Republic; International Clinical Research Center, Center for Biological and Cellular Engineering, St. Anne's University Hospital, Brno, Czech Republic
| | - Jakub Červinka
- Department of Experimental Biology, Faculty of Science, Masaryk University, Brno, Czech Republic; International Clinical Research Center, Center for Biological and Cellular Engineering, St. Anne's University Hospital, Brno, Czech Republic
| | - Elisabetta Biglieri
- Institute of Physiology, University of Zurich and Comprehensive Cancer Center, Zurich, Switzerland
| | - Jan Šmarda
- Department of Experimental Biology, Faculty of Science, Masaryk University, Brno, Czech Republic
| | - Lubor Borsig
- Institute of Physiology, University of Zurich and Comprehensive Cancer Center, Zurich, Switzerland
| | - Petr Beneš
- Department of Experimental Biology, Faculty of Science, Masaryk University, Brno, Czech Republic; International Clinical Research Center, Center for Biological and Cellular Engineering, St. Anne's University Hospital, Brno, Czech Republic
| | - Lucia Knopfová
- Department of Experimental Biology, Faculty of Science, Masaryk University, Brno, Czech Republic; International Clinical Research Center, Center for Biological and Cellular Engineering, St. Anne's University Hospital, Brno, Czech Republic.
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9
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Kaundal B, Kushwaha AC, Srivastava AK, Karmakar S, Choudhury SR. A non-viral nano-delivery system targeting epigenetic methyltransferase EZH2 for precise acute myeloid leukemia therapy. J Mater Chem B 2020; 8:8658-8670. [PMID: 32844866 DOI: 10.1039/d0tb01177k] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Acute myeloid leukemia (AML), which is common in the elderly population, accounts for poor long-term survival with a high possibility of relapse. The associated lack of currently developed therapeutics is directing the search for new therapeutic targets relating to AML. EZH2 (Enhancer of Zeste Homolog 2) is a histone methyltransferase member of the polycomb-group (PcG) family, and its significant overexpression in AML means it has emerged as a potential epigenetic target. Here, we propose the human serum albumin (HSA) nanoparticle based delivery of small interfering RNA (siRNA), which can target EZH2-expressing genes in AML. EZH2 specific siRNA loaded in a polyethyleneimine (PEI) conjugated HSA nanocarrier can overcome the systemic instability of siRNA and precisely target the AML cell population for increased EZH2 gene silencing. A stable nanosized complex (HSANPs-PEI@EZH2siRNA), achieved via the electrostatic interaction of PEI and EZH2 siRNA, shows increased systemic stability and hemocompatibility, and enhanced EZH2 gene silencing activity in vitro, compared to conventional transfection reagents. HSANPs-PEI@EZH2siRNA-treated AML cells showed downregulated EZH2, which is associated with a reduced level of Bmi-1 protein, and H3K27me3 and H2AK119ub modification. The ubiquitin-mediated proteasomal degradation pathway plays a critical role in the downregulation of associated proteins following HSANPs-PEI@EZH2siRNA exposure to AML cells. c-Myb is the AML-responsive transcription factor that directly binds on the EZH2 promoter and was downregulated in HSANPs-PEI@EZH2siRNA-treated AML cells. The systemic exposure to HSANPs-PEI@EZH2siRNA of AML engrafted immunodeficient nude mice displayed efficient EZH2 gene silencing and a reduced AML cell population in peripheral blood and bone marrow. The present study demonstrates a non-viral siRNA delivery system for epigenetic targeting based superior anti-leukemic therapy.
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Affiliation(s)
- Babita Kaundal
- Institute of Nano Science and Technology, Mohali, Punjab, India.
| | | | | | - Surajit Karmakar
- Institute of Nano Science and Technology, Mohali, Punjab, India.
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10
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Kaposi's Sarcoma-Associated Herpesvirus Drives a Super-Enhancer-Mediated Survival Gene Expression Program in Primary Effusion Lymphoma. mBio 2020; 11:mBio.01457-20. [PMID: 32843547 PMCID: PMC7448273 DOI: 10.1128/mbio.01457-20] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Kaposi's sarcoma-associated herpesvirus (KSHV) causes primary effusion lymphoma (PEL). The cellular transcription factor (TF) interferon (IFN) regulatory factor 4 (IRF4) is an essential oncogene in PEL, but its specific role in PEL and how KSHV deregulates IRF4 remain unknown. Here, we report that the KSHV latency protein viral interferon regulatory factor 3 (vIRF3) cooperates with IRF4 and cellular BATF (basic leucine zipper ATF-like TF) to drive a super-enhancer (SE)-mediated oncogenic transcriptional program in PEL. Chromatin immunoprecipitation coupled with next-generation sequencing (ChIP-Seq) experiments demonstrated that IRF4, vIRF3, and BATF cooccupy the SEs of key survival genes, in a pattern that is distinct from those seen with other IRF4-driven malignancies. All three proteins cooperatively drive SE-mediated IRF4 overexpression. Inactivation of vIRF3 and, to a lesser extent, BATF phenocopies the gene expression changes and loss of cellular viability observed upon inactivation of IRF4. In sum, this work suggests that KSHV vIRF3 and cellular IRF4 and BATF cooperate as oncogenic transcription factors on SEs to promote cellular survival and proliferation in KSHV-associated lymphomas.IMPORTANCE Kaposi's sarcoma-associated herpesvirus (KSHV) causes the aggressive disease primary effusion lymphoma (PEL). Here, we show that a viral transcription factor (vIRF3) cooperates with the cellular transcription factor IRF4 to control an oncogenic gene expression program in PEL cells. These proteins promote KSHV-mediated B cell transformation by activating the expression of prosurvival genes through super-enhancers. Our report thus demonstrates that this DNA tumor virus encodes a transcription factor that functions with cellular IRF4 to drive oncogenic transcriptional reprogramming.
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11
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Kaundal B, Srivastava AK, Dev A, Mohanbhai SJ, Karmakar S, Roy Choudhury S. Nanoformulation of EPZ011989 Attenuates EZH2–c-Myb Epigenetic Interaction by Proteasomal Degradation in Acute Myeloid Leukemia. Mol Pharm 2020; 17:604-621. [DOI: 10.1021/acs.molpharmaceut.9b01071] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Babita Kaundal
- Institute of Nano Science and Technology, Phase-10, Mohali (Habitat Center), Punjab 160062, India
| | - Anup K. Srivastava
- Institute of Nano Science and Technology, Phase-10, Mohali (Habitat Center), Punjab 160062, India
| | - Atul Dev
- Institute of Nano Science and Technology, Phase-10, Mohali (Habitat Center), Punjab 160062, India
| | - Soni Jignesh Mohanbhai
- Institute of Nano Science and Technology, Phase-10, Mohali (Habitat Center), Punjab 160062, India
| | - Surajit Karmakar
- Institute of Nano Science and Technology, Phase-10, Mohali (Habitat Center), Punjab 160062, India
| | - Subhasree Roy Choudhury
- Institute of Nano Science and Technology, Phase-10, Mohali (Habitat Center), Punjab 160062, India
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12
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Kumar H, Chattopadhyay S, Das N, Shree S, Patel D, Mohapatra J, Gurjar A, Kushwaha S, Singh AK, Dubey S, Lata K, Kushwaha R, Mohammed R, Dastidar KG, Yadav N, Vishwakarma AL, Gayen JR, Bandyopadhyay S, Chatterjee A, Jain MR, Tripathi AK, Trivedi AK, Chattopadhyay N, Ramachandran R, Sanyal S. Leprosy drug clofazimine activates peroxisome proliferator-activated receptor-γ and synergizes with imatinib to inhibit chronic myeloid leukemia cells. Haematologica 2019; 105:971-986. [PMID: 31371410 PMCID: PMC7109729 DOI: 10.3324/haematol.2018.194910] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Accepted: 07/12/2019] [Indexed: 12/12/2022] Open
Abstract
Leukemia stem cells contribute to drug-resistance and relapse in chronic myeloid leukemia (CML) and BCR-ABL1 inhibitor monotherapy fails to eliminate these cells, thereby necessitating alternate therapeutic strategies for patients CML. The peroxisome proliferator-activated receptor-γ (PPARγ) agonist pioglitazone downregulates signal transducer and activator of transcription 5 (STAT5) and in combination with imatinib induces complete molecular response in imatinib-refractory patients by eroding leukemia stem cells. Thiazolidinediones such as pioglitazone are, however, associated with severe side effects. To identify alternate therapeutic strategies for CML we screened Food and Drug Administration-approved drugs in K562 cells and identified the leprosy drug clofazimine as an inhibitor of viability of these cells. Here we show that clofazimine induced apoptosis of blood mononuclear cells derived from patients with CML, with a particularly robust effect in imatinib-resistant cells. Clofazimine also induced apoptosis of CD34+38- progenitors and quiescent CD34+ cells from CML patients but not of hematopoietic progenitor cells from healthy donors. Mechanistic evaluation revealed that clofazimine, via physical interaction with PPARγ, induced nuclear factor kB-p65 proteasomal degradation, which led to sequential myeloblastoma oncoprotein and peroxiredoxin 1 downregulation and concomitant induction of reactive oxygen species-mediated apoptosis. Clofazimine also suppressed STAT5 expression and consequently downregulated stem cell maintenance factors hypoxia-inducible factor-1α and -2α and Cbp/P300 interacting transactivator with Glu/Asp-rich carboxy-terminal domain 2 (CITED2). Combining imatinib with clofazimine caused a far superior synergy than that with pioglitazone, with clofazimine reducing the half maximal inhibitory concentration (IC50) of imatinib by >4 logs and remarkably eroding quiescent CD34+ cells. In a K562 xenograft study clofazimine and imatinib co-treatment showed more robust efficacy than the individual treatments. We propose clinical evaluation of clofazimine in imatinib-refractory CML.
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Affiliation(s)
- Harish Kumar
- Division of Biochemistry, CSIR-Central Drug Research Institute, Lucknow
| | - Sourav Chattopadhyay
- Division of Biochemistry, CSIR-Central Drug Research Institute, Lucknow.,AcSIR, CSIR-Central Drug Research Institute Campus, Lucknow
| | - Nabanita Das
- Division of Biochemistry, CSIR-Central Drug Research Institute, Lucknow
| | - Sonal Shree
- Division of Molecular and Structural Biology, CSIR-Central Drug Research Institute, Lucknow
| | - Dinesh Patel
- Zydus Research Center, Moraiya, Ahmedabad, Gujarat
| | | | - Anagha Gurjar
- Division of Biochemistry, CSIR-Central Drug Research Institute, Lucknow.,AcSIR, CSIR-Central Drug Research Institute Campus, Lucknow
| | - Sapana Kushwaha
- Division of Biochemistry, CSIR-Central Drug Research Institute, Lucknow
| | | | - Shikha Dubey
- Division of Molecular and Structural Biology, CSIR-Central Drug Research Institute, Lucknow
| | - Kiran Lata
- Division of Molecular and Structural Biology, CSIR-Central Drug Research Institute, Lucknow
| | - Rajesh Kushwaha
- Developmental Toxicology Laboratory, Systems Toxicology and Health Risk Assessment Group, CSIR-Indian Institute of Toxicology Research, Lucknow
| | - Riyazuddin Mohammed
- Pharmacokinetics and Metabolism Division, CSIR-Central Drug Research Institute, Lucknow
| | | | | | | | - Jiaur Rahaman Gayen
- Pharmacokinetics and Metabolism Division, CSIR-Central Drug Research Institute, Lucknow.,AcSIR, CSIR-Central Drug Research Institute Campus, Lucknow
| | - Sanghamitra Bandyopadhyay
- Developmental Toxicology Laboratory, Systems Toxicology and Health Risk Assessment Group, CSIR-Indian Institute of Toxicology Research, Lucknow
| | | | | | - Anil Kumar Tripathi
- Department of Clinical Hematology and Medical Oncology, King George's Medical University, Lucknow, Uttar Pradesh
| | - Arun Kumar Trivedi
- Division of Biochemistry, CSIR-Central Drug Research Institute, Lucknow.,AcSIR, CSIR-Central Drug Research Institute Campus, Lucknow
| | - Naibedya Chattopadhyay
- Division of Endocrinology, CSIR-Central Drug Research Institute, Lucknow, India.,AcSIR, CSIR-Central Drug Research Institute Campus, Lucknow
| | - Ravishankar Ramachandran
- AcSIR, CSIR-Central Drug Research Institute Campus, Lucknow.,Division of Molecular and Structural Biology, CSIR-Central Drug Research Institute, Lucknow
| | - Sabyasachi Sanyal
- Division of Biochemistry, CSIR-Central Drug Research Institute, Lucknow .,AcSIR, CSIR-Central Drug Research Institute Campus, Lucknow
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13
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Abstract
The c-Myb gene encodes a transcription factor that regulates cell proliferation, differentiation, and apoptosis through protein-protein interaction and transcriptional regulation of signaling pathways. The protein is frequently overexpressed in human leukemias, breast cancers, and other solid tumors suggesting that it is a bona fide oncogene. c-MYB is often overexpressed by translocation in human tumors with t(6;7)(q23;q34) resulting in c-MYB-TCRβ in T cell ALL, t(X;6)(p11;q23) with c-MYB-GATA1 in acute basophilic leukemia, and t(6;9)(q22-23;p23-24) with c-MYB-NF1B in adenoid cystic carcinoma. Antisense oligonucleotides to c-MYB were developed to purge bone marrow cells to eliminate tumor cells in leukemias. Recently, small molecules that inhibit c-MYB activity have been developed to disrupt its interaction with p300. The Dmp1 (cyclin D binding myb-like protein 1; Dmtf1) gene was isolated through its virtue for binding to cyclin D2. It is a transcription factor that has a Myb-like repeat for DNA binding. The Dmtf1 protein directly binds to the Arf promoter for transactivation and physically interacts with p53 to activate the p53 pathway. The gene is hemizygously deleted in 35-42% of human cancers and is associated with longer survival. The significances of aberrant expression of c-MYB and DMTF1 proteins in human cancers and their clinical significances are discussed.
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Affiliation(s)
- Elizabeth A. Fry
- The Department of Pathology, Wake Forest University School of Medicine, Medical Center Blvd., Winston-Salem, NC 27157 USA
| | - Kazushi Inoue
- The Department of Pathology, Wake Forest University School of Medicine, Medical Center Blvd., Winston-Salem, NC 27157 USA
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14
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Spagnuolo M, Regazzo G, De Dominici M, Sacconi A, Pelosi A, Korita E, Marchesi F, Pisani F, Magenta A, Lulli V, Cordone I, Mengarelli A, Strano S, Blandino G, Rizzo MG, Calabretta B. Transcriptional activation of the miR-17-92 cluster is involved in the growth-promoting effects of MYB in human Ph-positive leukemia cells. Haematologica 2018; 104:82-92. [PMID: 30076175 PMCID: PMC6312025 DOI: 10.3324/haematol.2018.191213] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2018] [Accepted: 07/27/2018] [Indexed: 01/07/2023] Open
Abstract
MicroRNAs, non-coding regulators of gene expression, are likely to function as important downstream effectors of many transcription factors including MYB. Optimal levels of MYB are required for transformation/maintenance of BCR-ABL-expressing cells. We investigated whether MYB silencing modulates microRNA expression in Philadelphia-positive (Ph+) leukemia cells and if MYB-regulated microRNAs are important for the “MYB addiction” of these cells. Thirty-five microRNAs were modulated by MYB silencing in lymphoid and erythromyeloid chronic myeloid leukemia-blast crisis BV173 and K562 cells; 15 of these were concordantly modulated in both lines. We focused on the miR-17-92 cluster because of its oncogenic role in tumors and found that: i) it is a direct MYB target; ii) it partially rescued the impaired proliferation and enhanced apoptosis of MYB-silenced BV173 cells. Moreover, we identified FRZB, a Wnt/β-catenin pathway inhibitor, as a novel target of the miR-17-92 cluster. High expression of MYB in blast cells from 2 Ph+leukemia patients correlated positively with the miR-17-92 cluster and inversely with FRZB. This expression pattern was also observed in a microarray dataset of 122 Ph+acute lymphoblastic leukemias. In vivo experiments in NOD scid gamma mice injected with BV173 cells confirmed that FRZB functions as a Wnt/β-catenin inhibitor even as they failed to demonstrate that this pathway is important for BV173-dependent leukemogenesis. These studies illustrate the global effects of MYB expression on the microRNAs profile of Ph+cells and supports the concept that the “MYB addiction” of these cells is, in part, caused by modulation of microRNA-regulated pathways affecting cell proliferation and survival.
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Affiliation(s)
- Manuela Spagnuolo
- Department of Research, Advanced Diagnostics and Technological Innovation, Oncogenomic and Epigenetic Unit, Translational Research Area, IRCCS - Regina Elena National Cancer Institute, Rome, Italy
| | - Giulia Regazzo
- Department of Research, Advanced Diagnostics and Technological Innovation, Oncogenomic and Epigenetic Unit, Translational Research Area, IRCCS - Regina Elena National Cancer Institute, Rome, Italy
| | - Marco De Dominici
- Department of Cancer Biology and Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA, USA
| | - Andrea Sacconi
- Department of Research, Advanced Diagnostics and Technological Innovation, Oncogenomic and Epigenetic Unit, Translational Research Area, IRCCS - Regina Elena National Cancer Institute, Rome, Italy
| | - Andrea Pelosi
- Department of Research, Advanced Diagnostics and Technological Innovation, Oncogenomic and Epigenetic Unit, Translational Research Area, IRCCS - Regina Elena National Cancer Institute, Rome, Italy
| | - Etleva Korita
- Department of Research, Advanced Diagnostics and Technological Innovation, Oncogenomic and Epigenetic Unit, Translational Research Area, IRCCS - Regina Elena National Cancer Institute, Rome, Italy
| | - Francesco Marchesi
- Department of Clinical and Experimental Oncology-Hematology and Stem Cell Transplant Unit, IRCCS - Regina Elena National Cancer Institute, Rome, Italy
| | - Francesco Pisani
- Department of Clinical and Experimental Oncology-Hematology and Stem Cell Transplant Unit, IRCCS - Regina Elena National Cancer Institute, Rome, Italy
| | - Alessandra Magenta
- Istituto Dermopatico dell'Immacolata-IRCCS, FLMM, Laboratorio di Patologia Vascolare, Rome, Italy
| | - Valentina Lulli
- Department of Oncology and Molecular Medicine, Istituto Superiore di Sanità, Rome, Italy
| | - Iole Cordone
- Department of Research, Advanced Diagnostics and Technological Innovation, Clinical Pathology Unit, IRCCS - Regina Elena National Cancer Institute, Rome, Italy
| | - Andrea Mengarelli
- Department of Clinical and Experimental Oncology-Hematology and Stem Cell Transplant Unit, IRCCS - Regina Elena National Cancer Institute, Rome, Italy
| | - Sabrina Strano
- Department of Research, Advanced Diagnostics and Technological Innovation, Oncogenomic and Epigenetic Unit, Translational Research Area, IRCCS - Regina Elena National Cancer Institute, Rome, Italy
| | - Giovanni Blandino
- Department of Research, Advanced Diagnostics and Technological Innovation, Oncogenomic and Epigenetic Unit, Translational Research Area, IRCCS - Regina Elena National Cancer Institute, Rome, Italy
| | - Maria G Rizzo
- Department of Research, Advanced Diagnostics and Technological Innovation, Oncogenomic and Epigenetic Unit, Translational Research Area, IRCCS - Regina Elena National Cancer Institute, Rome, Italy
| | - Bruno Calabretta
- Department of Cancer Biology and Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA, USA
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15
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Liu X, Xu Y, Han L, Yi Y. Reassessing the Potential of Myb-targeted Anti-cancer Therapy. J Cancer 2018; 9:1259-1266. [PMID: 29675107 PMCID: PMC5907674 DOI: 10.7150/jca.23992] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2017] [Accepted: 02/28/2018] [Indexed: 01/27/2023] Open
Abstract
Transcription factor MYB is essential for the tumorigenesis of multiple cancers, especially leukemia, breast cancer, colon cancer, adenoid cystic carcinoma and brain cancer. Thus, MYB has been regarded as an attractive target for tumor therapy. However, pioneer studies of antisense oligodeoxynucleotides against MYB, which were launched three decades ago in leukemia therapy, were discontinued because of their unsatisfactory clinical outcomes. In recent years, the roles of MYB in tumor transformation have become increasingly clear. Moreover, the regulatory mechanisms of MYB, such as the vital effects of MYB co-regulators on MYB activity and of transcriptional elongation on MYB expression, have been unveiled. These observations have underpinned novel approaches in inhibiting MYB. This review discusses the structure, function and regulation of MYB, focusing on recent insights into MYB-associated oncogenesis and how MYB-targeted therapeutics can be explored. Additionally, the main MYB-targeted therapies, including novel genetic therapy, RNA interference, microRNAs and low-molecular-weight compounds, which are especially promising inhibitors that target MYB co-regulators and transcriptional elongation, are described, and their prospects are assessed.
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Affiliation(s)
- Xiaofeng Liu
- Department of Hematology, the Second Xiangya Hospital, Central South University, Changsha, Hunan Province, P.R. China
| | - Yunxiao Xu
- Department of Hematology, the Second Xiangya Hospital, Central South University, Changsha, Hunan Province, P.R. China
| | - Liping Han
- School of Life Science, Changchun Normal University, Changchun, Jilin Province, P.R. China
| | - Yan Yi
- Department of Hematology, the Second Xiangya Hospital, Central South University, Changsha, Hunan Province, P.R. China
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16
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Nguyen N, Vishwakarma BA, Oakley K, Han Y, Przychodzen B, Maciejewski JP, Du Y. Myb expression is critical for myeloid leukemia development induced by Setbp1 activation. Oncotarget 2018; 7:86300-86312. [PMID: 27863435 PMCID: PMC5349915 DOI: 10.18632/oncotarget.13383] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Accepted: 11/07/2016] [Indexed: 11/25/2022] Open
Abstract
SETBP1 missense mutations have been frequently identified in multiple myeloid neoplasms; however, their oncogenic potential remains unclear. Here we show that expression of Setbp1 mutants carrying two such mutations in mouse bone marrow progenitors efficiently induced development of acute myeloid leukemias (AMLs) in irradiated recipient mice with significantly shorter latencies and greater penetrance than expression of wild-type Setbp1, suggesting that these mutations are highly oncogenic. The increased oncogenicity of Setbp1 missense mutants could be due in part to their capability to drive significantly higher target gene transcription. We further identify Myb as a critical mediator of Setbp1-induced self-renewal as its knockdown caused efficient differentiation of myeloid progenitors immortalized by wild-type Setbp1 and Setbp1 missense mutants. Interestingly, Myb is also a direct transcriptional target of Setbp1 and Setbp1 missense mutants as they directly bind to the Myb locus in immortalized cells and dramatically activate a critical enhancer/promoter region of Myb in luciferase reporter assays. Furthermore, Myb knockdown in Setbp1 and Setbp1 missense mutations-induced AML cells also efficiently induced their differentiation in culture and significantly prolonged the survival of their secondary recipient mice, suggesting that targeting MYB pathway could be a promising strategy for treating human myeloid neoplasms with SETBP1 activation.
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Affiliation(s)
- Nhu Nguyen
- Department of Pediatrics, Uniformed Services University of the Health Sciences, Bethesda, MD, USA
| | - Bandana A Vishwakarma
- Department of Pediatrics, Uniformed Services University of the Health Sciences, Bethesda, MD, USA
| | - Kevin Oakley
- Department of Pediatrics, Uniformed Services University of the Health Sciences, Bethesda, MD, USA
| | - Yufen Han
- Department of Pediatrics, Uniformed Services University of the Health Sciences, Bethesda, MD, USA
| | - Bartlomiej Przychodzen
- Department of Translational Hematology and Oncology Research, Taussig Cancer Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Jaroslaw P Maciejewski
- Department of Translational Hematology and Oncology Research, Taussig Cancer Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Yang Du
- Department of Pediatrics, Uniformed Services University of the Health Sciences, Bethesda, MD, USA
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17
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Coulibaly A, Haas A, Steinmann S, Jakobs A, Schmidt TJ, Klempnauer KH. The natural anti-tumor compound Celastrol targets a Myb-C/EBPβ-p300 transcriptional module implicated in myeloid gene expression. PLoS One 2018; 13:e0190934. [PMID: 29394256 PMCID: PMC5796697 DOI: 10.1371/journal.pone.0190934] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Accepted: 12/22/2017] [Indexed: 12/31/2022] Open
Abstract
Myb is a key regulator of hematopoietic progenitor cell proliferation and differentiation and has emerged as a potential target for the treatment of acute leukemia. Using a myeloid cell line with a stably integrated Myb-inducible reporter gene as a screening tool we have previously identified Celastrol, a natural compound with anti-tumor activity, as a potent Myb inhibitor that disrupts the interaction of Myb with the co-activator p300. We showed that Celastrol inhibits the proliferation of acute myeloid leukemia (AML) cells and prolongs the survival of mice in an in vivo model of AML, demonstrating that targeting Myb with a small-molecule inhibitor is feasible and might have potential as a therapeutic approach against AML. Recently we became aware that the reporter system used for Myb inhibitor screening also responds to inhibition of C/EBPβ, a transcription factor known to cooperate with Myb in myeloid cells. By re-investigating the inhibitory potential of Celastrol we have found that Celastrol also strongly inhibits the activity of C/EBPβ by disrupting its interaction with the Taz2 domain of p300. Together with previous studies our work reveals that Celastrol independently targets Myb and C/EBPβ by disrupting the interaction of both transcription factors with p300. Myb, C/EBPβ and p300 cooperate in myeloid-specific gene expression and, as shown recently, are associated with so-called super-enhancers in AML cells that have been implicated in the maintenance of the leukemia. We hypothesize that the ability of Celastrol to disrupt the activity of a transcriptional Myb-C/EBPβ-p300 module might explain its promising anti-leukemic activity.
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Affiliation(s)
- Anna Coulibaly
- Institute for Biochemistry, Westfälische-Wilhelms-Universität, D-48149 Münster, Germany
| | - Astrid Haas
- Institute for Biochemistry, Westfälische-Wilhelms-Universität, D-48149 Münster, Germany
| | - Simone Steinmann
- Institute for Biochemistry, Westfälische-Wilhelms-Universität, D-48149 Münster, Germany
| | - Anke Jakobs
- Institute for Biochemistry, Westfälische-Wilhelms-Universität, D-48149 Münster, Germany
| | - Thomas J. Schmidt
- Institute for Pharmaceutical Biology and Phytochemistry, Westfälische-Wilhelms-Universität, D-48149 Münster, Germany
| | - Karl-Heinz Klempnauer
- Institute for Biochemistry, Westfälische-Wilhelms-Universität, D-48149 Münster, Germany
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18
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Xu Y, Milazzo JP, Somerville TDD, Tarumoto Y, Huang YH, Ostrander EL, Wilkinson JE, Challen GA, Vakoc CR. A TFIID-SAGA Perturbation that Targets MYB and Suppresses Acute Myeloid Leukemia. Cancer Cell 2018; 33:13-28.e8. [PMID: 29316427 PMCID: PMC5764110 DOI: 10.1016/j.ccell.2017.12.002] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Revised: 09/22/2017] [Accepted: 12/05/2017] [Indexed: 01/08/2023]
Abstract
Targeting of general coactivators is an emerging strategy to interfere with oncogenic transcription factors (TFs). However, coactivator perturbations often lead to pleiotropic effects by influencing numerous TFs. Here we identify TAF12, a subunit of TFIID and SAGA coactivator complexes, as a selective requirement for acute myeloid leukemia (AML) progression. We trace this dependency to a direct interaction between the TAF12/TAF4 histone-fold heterodimer and the transactivation domain of MYB, a TF with established roles in leukemogenesis. Ectopic expression of the TAF4 histone-fold fragment can efficiently squelch TAF12 in cells, suppress MYB, and regress AML in mice. Our study reveals a strategy for potent MYB inhibition in AML and highlights how an oncogenic TF can be selectively neutralized by targeting a general coactivator complex.
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Affiliation(s)
- Yali Xu
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA; Molecular and Cellular Biology Program, Stony Brook University, New York, NY 11794, USA
| | - Joseph P Milazzo
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA
| | | | - Yusuke Tarumoto
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA
| | - Yu-Han Huang
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA
| | - Elizabeth L Ostrander
- Division of Oncology, Department of Internal Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - John E Wilkinson
- ULAM/Department of Pathology, University of Michigan School of Medicine, Ann Arbor, MI 48109, USA
| | - Grant A Challen
- Division of Oncology, Department of Internal Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA
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19
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De Dominici M, Porazzi P, Soliera AR, Mariani SA, Addya S, Fortina P, Peterson LF, Spinelli O, Rambaldi A, Martinelli G, Ferrari A, Iacobucci I, Calabretta B. Targeting CDK6 and BCL2 Exploits the "MYB Addiction" of Ph + Acute Lymphoblastic Leukemia. Cancer Res 2017; 78:1097-1109. [PMID: 29233926 DOI: 10.1158/0008-5472.can-17-2644] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Revised: 10/25/2017] [Accepted: 12/08/2017] [Indexed: 01/09/2023]
Abstract
Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph+ ALL) is currently treated with BCR-ABL1 tyrosine kinase inhibitors (TKI) in combination with chemotherapy. However, most patients develop resistance to TKI through BCR-ABL1-dependent and -independent mechanisms. Newly developed TKI can target Ph+ ALL cells with BCR-ABL1-dependent resistance; however, overcoming BCR-ABL1-independent mechanisms of resistance remains challenging because transcription factors, which are difficult to inhibit, are often involved. We show here that (i) the growth of Ph+ ALL cell lines and primary cells is highly dependent on MYB-mediated transcriptional upregulation of CDK6, cyclin D3, and BCL2, and (ii) restoring their expression in MYB-silenced Ph+ ALL cells rescues their impaired proliferation and survival. Levels of MYB and CDK6 were highly correlated in adult Ph+ ALL (P = 0.00008). Moreover, Ph+ ALL cells exhibited a specific requirement for CDK6 but not CDK4 expression, most likely because, in these cells, CDK6 was predominantly localized in the nucleus, whereas CDK4 was almost exclusively cytoplasmic. Consistent with their essential role in Ph+ ALL, pharmacologic inhibition of CDK6 and BCL2 markedly suppressed proliferation, colony formation, and survival of Ph+ ALL cells ex vivo and in mice. In summary, these findings provide a proof-of-principle, rational strategy to target the MYB "addiction" of Ph+ ALL.Significance: MYB blockade can suppress Philadelphia chromosome-positive leukemia in mice, suggesting that this therapeutic strategy may be useful in patients who develop resistance to imatinib and other TKIs used to treat this disease. Cancer Res; 78(4); 1097-109. ©2017 AACR.
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Affiliation(s)
- Marco De Dominici
- Department of Cancer Biology, Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Patrizia Porazzi
- Department of Cancer Biology, Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Angela Rachele Soliera
- Department of Diagnostic, Clinical Medicine and Public Health, University of Modena, Modena, Italy
| | - Samanta A Mariani
- Department of Cancer Biology, Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Sankar Addya
- Department of Cancer Biology, Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Paolo Fortina
- Department of Cancer Biology, Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Luke F Peterson
- Division of Hematology and Oncology, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan
| | - Orietta Spinelli
- Hematology and Bone Marrow Transplant Unit, Ospedale Papa Giovanni XXIII, Bergamo, Italy
| | - Alessandro Rambaldi
- Hematology and Bone Marrow Transplant Unit, Ospedale Papa Giovanni XXIII, Bergamo, Italy
| | - Giovanni Martinelli
- Department of Hematology and Istituto L. and E. Seragnoli, University of Bologna, Bologna, Italy
| | - Anna Ferrari
- Department of Hematology and Istituto L. and E. Seragnoli, University of Bologna, Bologna, Italy
| | - Ilaria Iacobucci
- Department of Hematology and Istituto L. and E. Seragnoli, University of Bologna, Bologna, Italy
| | - Bruno Calabretta
- Department of Cancer Biology, Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, Pennsylvania.
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Negi V, Vishwakarma BA, Chu S, Oakley K, Han Y, Bhatia R, Du Y. Hoxa9 and Hoxa10 induce CML myeloid blast crisis development through activation of Myb expression. Oncotarget 2017; 8:98853-98864. [PMID: 29228732 PMCID: PMC5716772 DOI: 10.18632/oncotarget.22008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2017] [Accepted: 09/30/2017] [Indexed: 11/25/2022] Open
Abstract
Mechanisms underlying the progression of Chronic Myeloid Leukemia (CML) from chronic phase to myeloid blast crisis are poorly understood. Our previous studies have suggested that overexpression of SETBP1 can drive this progression by conferring unlimited self-renewal capability to granulocyte macrophage progenitors (GMPs). Here we show that overexpression of Hoxa9 or Hoxa10, both transcriptional targets of Setbp1, is also sufficient to induce self-renewal of primary myeloid progenitors, causing their immortalization in culture. More importantly, both are able to cooperate with BCR/ABL to consistently induce transformation of mouse GMPs and development of aggressive leukemias resembling CML myeloid blast crisis, suggesting that either gene can drive CML progression by promoting the self-renewal of GMPs. We further identify Myb as a common critical target for Hoxa9 and Hoxa10 in inducing self-renewal of myeloid progenitors as Myb knockdown significantly reduced colony-forming potential of myeloid progenitors immortalized by the expression of either gene. Interestingly, Myb is also capable of immortalizing primary myeloid progenitors in culture and cooperating with BCR/ABL to induce leukemic transformation of mouse GMPs. Significantly increased levels of MYB transcript also were detected in all human CML blast crisis samples examined over chronic phase samples, further suggesting the possibility that MYB overexpression may play a prevalent role in driving human CML myeloid blast crisis development. In summary, our results identify overexpression of HOXA9, HOXA10, and MYB as critical drivers of CML progression, and suggest MYB as a key therapeutic target for inhibiting the self-renewal of leukemia-initiating cells in CML myeloid blast crisis patients.
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Affiliation(s)
- Vijay Negi
- Department of Pediatrics, Uniformed Services University of the Health Sciences, Bethesda, MD, USA
| | - Bandana A Vishwakarma
- Department of Pediatrics, Uniformed Services University of the Health Sciences, Bethesda, MD, USA
| | - Su Chu
- Division of Hematology/Oncology, Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Kevin Oakley
- Department of Pediatrics, Uniformed Services University of the Health Sciences, Bethesda, MD, USA
| | - Yufen Han
- Department of Pediatrics, Uniformed Services University of the Health Sciences, Bethesda, MD, USA
| | - Ravi Bhatia
- Division of Hematology/Oncology, Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Yang Du
- Department of Pediatrics, Uniformed Services University of the Health Sciences, Bethesda, MD, USA
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21
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Targeting acute myeloid leukemia by drug-induced c-MYB degradation. Leukemia 2017; 32:882-889. [PMID: 29089643 DOI: 10.1038/leu.2017.317] [Citation(s) in RCA: 71] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2017] [Revised: 09/27/2017] [Accepted: 10/18/2017] [Indexed: 12/16/2022]
Abstract
Despite advances in our understanding of the molecular basis for particular subtypes of acute myeloid leukemia (AML), effective therapy remains a challenge for many individuals suffering from this disease. A significant proportion of both pediatric and adult AML patients cannot be cured and since the upper limits of chemotherapy intensification have been reached, there is an urgent need for novel therapeutic approaches. The transcription factor c-MYB has been shown to play a central role in the development and progression of AML driven by several different oncogenes, including mixed lineage leukemia (MLL)-fusion genes. Here, we have used a c-MYB gene expression signature from MLL-rearranged AML to probe the Connectivity Map database and identified mebendazole as a c-MYB targeting drug. Mebendazole induces c-MYB degradation via the proteasome by interfering with the heat shock protein 70 (HSP70) chaperone system. Transient exposure to mebendazole is sufficient to inhibit colony formation by AML cells, but not normal cord blood-derived cells. Furthermore, mebendazole is effective at impairing AML progression in vivo in mouse xenotransplantation experiments. In the context of widespread human use of mebendazole, our data indicate that mebendazole-induced c-MYB degradation represents a safe and novel therapeutic approach for AML.
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22
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Coccaro N, Tota G, Zagaria A, Anelli L, Specchia G, Albano F. SETBP1 dysregulation in congenital disorders and myeloid neoplasms. Oncotarget 2017; 8:51920-51935. [PMID: 28881700 PMCID: PMC5584301 DOI: 10.18632/oncotarget.17231] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2017] [Accepted: 03/30/2017] [Indexed: 01/19/2023] Open
Abstract
Myeloid malignancies are characterized by an extreme molecular heterogeneity, and many efforts have been made in the past decades to clarify the mechanisms underlying their pathogenesis. In this scenario SET binding protein 1 (SETBP1) has attracted a lot of interest as a new oncogene and potential marker, in addition to its involvement in the Schinzel-Giedon syndrome (SGS). Our review starts with the analysis of the structural characteristics of SETBP1, and extends to its corresponding physiological and pathological functions. Next, we describe the prevalence of SETBP1 mutations in congenital diseases and in hematologic malignancies, exploring how its alterations might contribute to tumor development and provoke clinical effects. Finally, we consider to understand how SETBP1 activation could be exploited in molecular medicine to enhance the cure rate.
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Affiliation(s)
- Nicoletta Coccaro
- Department of Emergency and Organ Transplantation (D.E.T.O.), Hematology Section, University of Bari, Bari, Italy
| | - Giuseppina Tota
- Department of Emergency and Organ Transplantation (D.E.T.O.), Hematology Section, University of Bari, Bari, Italy
| | - Antonella Zagaria
- Department of Emergency and Organ Transplantation (D.E.T.O.), Hematology Section, University of Bari, Bari, Italy
| | - Luisa Anelli
- Department of Emergency and Organ Transplantation (D.E.T.O.), Hematology Section, University of Bari, Bari, Italy
| | - Giorgina Specchia
- Department of Emergency and Organ Transplantation (D.E.T.O.), Hematology Section, University of Bari, Bari, Italy
| | - Francesco Albano
- Department of Emergency and Organ Transplantation (D.E.T.O.), Hematology Section, University of Bari, Bari, Italy
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23
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Chi K, Li Y, Xu L, Wang X. A novel recurrent copy number loss region on 6q23.3 in MDS-related myeloid malignancy patients with stable survival conditions. Leuk Lymphoma 2017; 58:2470-2479. [PMID: 28394181 DOI: 10.1080/10428194.2017.1292357] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Metaphase cytogenetics (MC) karyotyping is a fundamental way to approach cytogenetic pathogenesis of MDS-related myeloid malignancies. However, in some patients, the results are normal while the patients often show discrepancies in survival conditions. To explain this question, we analyzed CytoScan™ HD array results of 20 MC-normal/failure patients who were followed up for three years. Exon sequencing was performed in genes RUNX1, TP53, ASXL1, and TET2. The array enabled the detection of additional aberrations in 16 (80%) patients. Eight patients were detected with cryptic copy number losses and six of them got aggressive disease conditions. RUNX1 mutations were sequenced in P110 and P114. Most importantly, two patients (P114 and P116) with copy number loss aberrations got stable survival conditions during follow-ups, and a novel recurrent copy number loss region harboring the proto-oncogene MYB was detected on chromosome 6q23.3 in both of them, which might benefit the survival of the patients.
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Affiliation(s)
- Kun Chi
- a Department of Laboratory Medicine , Qingdao Women & Children's Hospital , Qingdao , China.,b State Key Laboratory of Medical Genomics , Shanghai Institute of Hematology, Ruijin Hospital, Shanghai Jiaotong University School of Medicine , Shanghai , China
| | - Yang Li
- b State Key Laboratory of Medical Genomics , Shanghai Institute of Hematology, Ruijin Hospital, Shanghai Jiaotong University School of Medicine , Shanghai , China
| | - Lan Xu
- c Department of Hematology , Ruijin Hospital, Shanghai Jiaotong University School of Medicine , Shanghai , China
| | - Xuefeng Wang
- d Department of Laboratory Medicine , Ruijin Hospital, Shanghai Jiaotong University School of Medicine , Shanghai , China
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Roe JS, Vakoc CR. The Essential Transcriptional Function of BRD4 in Acute Myeloid Leukemia. COLD SPRING HARBOR SYMPOSIA ON QUANTITATIVE BIOLOGY 2017; 81:61-66. [PMID: 28174254 DOI: 10.1101/sqb.2016.81.031039] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Acute myeloid leukemia (AML) is often initiated by genetic alterations of machineries that regulate chromatin and transcription, thereby blocking cell differentiation. Such mechanisms may also render leukemia cells vulnerable to perturbations of transcriptional regulators, which includes small molecules targeting the coactivator protein BRD4. Numerous studies have validated BRD4 as a therapeutic target in diverse subtypes of AML; however, the vital function of BRD4 in this disease is only beginning to be understood. Here we discuss the recent progress in elucidating the transcriptional function of BRD4 in AML cells, with an emphasis on the desirable attributes, but also the inherent limitations, of targeting general coactivator proteins as cancer therapy.
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Affiliation(s)
- Jae-Seok Roe
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724
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25
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Uttarkar S, Frampton J, Klempnauer KH. Targeting the transcription factor Myb by small-molecule inhibitors. Exp Hematol 2016; 47:31-35. [PMID: 28017646 DOI: 10.1016/j.exphem.2016.12.003] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2016] [Accepted: 12/10/2016] [Indexed: 11/18/2022]
Abstract
The transcription factor Myb is a key regulator of hematopoietic cell proliferation, differentiation, and survival and has been implicated in the development of leukemia and several other human cancers. Pharmacological inhibition of Myb is therefore emerging as a potential therapeutic strategy. Recently, the first low-molecular-weight compounds that show Myb inhibitory activity have been identified. Characterization of these compounds suggests disruption of the protein-protein-interaction of Myb and the coactivator p300 as a suitable strategy to inhibit Myb.
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Affiliation(s)
| | - Jon Frampton
- Institute of Cancer and Genomic Sciences, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham, United Kingdom
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26
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Uttarkar S, Piontek T, Dukare S, Schomburg C, Schlenke P, Berdel WE, Müller-Tidow C, Schmidt TJ, Klempnauer KH. Small-Molecule Disruption of the Myb/p300 Cooperation Targets Acute Myeloid Leukemia Cells. Mol Cancer Ther 2016; 15:2905-2915. [PMID: 27707899 DOI: 10.1158/1535-7163.mct-16-0185] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2016] [Revised: 09/07/2016] [Accepted: 09/26/2016] [Indexed: 11/16/2022]
Abstract
The transcription factor c-Myb is essential for the proliferation of hematopoietic cells and has been implicated in the development of leukemia and other human cancers. Pharmacologic inhibition of Myb is therefore emerging as a potential therapeutic strategy for these diseases. By using a Myb reporter cell line, we have identified plumbagin and several naphthoquinones as potent low-molecular weight Myb inhibitors. We demonstrate that these compounds inhibit c-Myb by binding to the c-Myb transactivation domain and disrupting the cooperation of c-Myb with the coactivator p300, a major driver of Myb activity. Naphthoquinone-induced inhibition of c-Myb suppresses Myb target gene expression and induces the differentiation of the myeloid leukemia cell line HL60. We demonstrate that murine and human primary acute myeloid leukemia cells are more sensitive to naphthoquinone-induced inhibition of clonogenic proliferation than normal hematopoietic progenitor cells. Overall, our work demonstrates for the first time the potential of naphthoquinones as small-molecule Myb inhibitors that may have therapeutic potential for the treatment of leukemia and other tumors driven by deregulated Myb. Mol Cancer Ther; 15(12); 2905-15. ©2016 AACR.
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Affiliation(s)
- Sagar Uttarkar
- Institute for Biochemistry, Westfälische Wilhelms-Universität, Münster, Germany
| | - Therese Piontek
- Institute for Pharmaceutical Biology and Phytochemistry, Westfälische Wilhelms-Universität, Münster, Germany
| | - Sandeep Dukare
- Institute for Biochemistry, Westfälische Wilhelms-Universität, Münster, Germany
| | - Caroline Schomburg
- Institute for Pharmaceutical Biology and Phytochemistry, Westfälische Wilhelms-Universität, Münster, Germany
| | - Peter Schlenke
- Department of Blood Group Serology and Transfusion Medicine, Medical University Graz, Graz, Austria
| | - Wolfgang E Berdel
- Department of Medicine A, Hematology and Oncology, Westfälische Wilhelms-Universität, Münster, Germany
| | - Carsten Müller-Tidow
- Department of Medicine, Hematology and Oncology, University of Halle, Halle, Germany
| | - Thomas J Schmidt
- Institute for Pharmaceutical Biology and Phytochemistry, Westfälische Wilhelms-Universität, Münster, Germany
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27
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Prinzhorn W, Stehle M, Kleiner H, Ruppenthal S, Müller MC, Hofmann WK, Fabarius A, Seifarth W. c-MYB is a transcriptional regulator of ESPL1/Separase in BCR-ABL-positive chronic myeloid leukemia. Biomark Res 2016; 4:5. [PMID: 26937281 PMCID: PMC4774018 DOI: 10.1186/s40364-016-0059-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2015] [Accepted: 02/24/2016] [Indexed: 01/05/2023] Open
Abstract
Background Genomic instability and clonal evolution are hallmarks of progressing chronic myeloid leukemia (CML). Recently, we have shown that clonal evolution and blast crisis correlate with altered expression and activity of Separase, a cysteine endopeptidase that is a mitotic key player in chromosomal segregation and centriole duplication. Hyperactivation of Separase in human hematopoietic cells has been linked to a feedback mechanism that posttranslationally stimulates Separase proteolytic activity after imatinib therapy-induced reduction of Separase protein levels. Methods and Results In search for potential therapy-responsive transcriptional mechanisms we have investigated the role of the transcription factor c-MYB for Separase expression in CML cell lines (LAMA-84, K562, BV-173) and in clinical samples. Quantitative RT-PCR and Western blot immunostaining experiments revealed that c-MYB expression levels are decreased in an imatinib-dependent manner and positively correlate with Separase expression levels in cell lines and in clinical CML samples. RNA silencing of c-MYB expression in CML cell lines resulted in reduced Separase protein levels. Gelshift and ChIP assays confirmed that c-MYB binds to a putative c-MYB binding sequence located within the ESPL1 promoter. Conclusions Our data suggest that ESPL1/Separase is a regulatory target of c-MYB. Therefore, c-MYB, known to be required for BCR-ABL-dependent transformation of hematopoietic progenitors and leukemogenesis, may also control the Separase-dependent fidelity of mitotic chromosomal segregation and centriole duplication essential for maintenance of genomic stability.
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Affiliation(s)
- Wiltrud Prinzhorn
- III. Medizinische Klinik (Hämatologie und Onkologie), Wissenschaftliches Labor, Medizinische Fakultät Mannheim der Universität Heidelberg, Pettenkofer Str. 22, 68169 Mannheim, Germany
| | - Michael Stehle
- III. Medizinische Klinik (Hämatologie und Onkologie), Wissenschaftliches Labor, Medizinische Fakultät Mannheim der Universität Heidelberg, Pettenkofer Str. 22, 68169 Mannheim, Germany
| | - Helga Kleiner
- III. Medizinische Klinik (Hämatologie und Onkologie), Wissenschaftliches Labor, Medizinische Fakultät Mannheim der Universität Heidelberg, Pettenkofer Str. 22, 68169 Mannheim, Germany
| | - Sabrina Ruppenthal
- III. Medizinische Klinik (Hämatologie und Onkologie), Wissenschaftliches Labor, Medizinische Fakultät Mannheim der Universität Heidelberg, Pettenkofer Str. 22, 68169 Mannheim, Germany
| | - Martin C Müller
- III. Medizinische Klinik (Hämatologie und Onkologie), Wissenschaftliches Labor, Medizinische Fakultät Mannheim der Universität Heidelberg, Pettenkofer Str. 22, 68169 Mannheim, Germany
| | - Wolf-Karsten Hofmann
- III. Medizinische Klinik (Hämatologie und Onkologie), Wissenschaftliches Labor, Medizinische Fakultät Mannheim der Universität Heidelberg, Pettenkofer Str. 22, 68169 Mannheim, Germany
| | - Alice Fabarius
- III. Medizinische Klinik (Hämatologie und Onkologie), Wissenschaftliches Labor, Medizinische Fakultät Mannheim der Universität Heidelberg, Pettenkofer Str. 22, 68169 Mannheim, Germany
| | - Wolfgang Seifarth
- III. Medizinische Klinik (Hämatologie und Onkologie), Wissenschaftliches Labor, Medizinische Fakultät Mannheim der Universität Heidelberg, Pettenkofer Str. 22, 68169 Mannheim, Germany
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28
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Targeting acute myeloid leukemia with a small molecule inhibitor of the Myb/p300 interaction. Blood 2015; 127:1173-82. [PMID: 26631113 DOI: 10.1182/blood-2015-09-668632] [Citation(s) in RCA: 77] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2015] [Accepted: 11/19/2015] [Indexed: 12/17/2022] Open
Abstract
The transcription factor Myb plays a key role in the hematopoietic system and has been implicated in the development of leukemia and other human cancers. Inhibition of Myb is therefore emerging as a potential therapeutic strategy for these diseases. However, because of a lack of suitable inhibitors, the feasibility of therapeutic approaches based on Myb inhibition has not been explored. We have identified the triterpenoid Celastrol as a potent low-molecular-weight inhibitor of the interaction of Myb with its cooperation partner p300. We demonstrate that Celastrol suppresses the proliferative potential of acute myeloid leukemia (AML) cells while not affecting normal hematopoietic progenitor cells. Furthermore, Celastrol prolongs the survival of mice in a model of an aggressive AML. Overall, our work demonstrates the therapeutic potential of a small molecule inhibitor of the Myb/p300 interaction for the treatment of AML and provides a starting point for the further development of Myb-inhibitory compounds for the treatment of leukemia and, possibly, other tumors driven by deregulated Myb.
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29
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Roe JS, Mercan F, Rivera K, Pappin DJ, Vakoc CR. BET Bromodomain Inhibition Suppresses the Function of Hematopoietic Transcription Factors in Acute Myeloid Leukemia. Mol Cell 2015; 58:1028-39. [PMID: 25982114 PMCID: PMC4475489 DOI: 10.1016/j.molcel.2015.04.011] [Citation(s) in RCA: 266] [Impact Index Per Article: 29.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2015] [Revised: 03/06/2015] [Accepted: 04/03/2015] [Indexed: 12/12/2022]
Abstract
The bromodomain and extraterminal (BET) protein BRD4 is a validated drug target in leukemia, yet its regulatory function in this disease is not well understood. Here, we show that BRD4 chromatin occupancy in acute myeloid leukemia closely correlates with the hematopoietic transcription factors (TFs) PU.1, FLI1, ERG, C/EBPα, C/EBPβ, and MYB at nucleosome-depleted enhancer and promoter regions. We provide evidence that these TFs, in conjunction with the lysine acetyltransferase activity of p300/CBP, facilitate BRD4 recruitment to their occupied sites to promote transcriptional activation. Chemical inhibition of BET bromodomains was found to suppress the functional output of each hematopoietic TF, thereby interfering with essential lineage-specific transcriptional circuits in this disease. These findings reveal a chromatin-based signaling cascade comprised of hematopoietic TFs, p300/CBP, and BRD4 that supports leukemia maintenance and is suppressed by BET bromodomain inhibition.
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Affiliation(s)
- Jae-Seok Roe
- Cold Spring Harbor Laboratory, 1 Bungtown Road, Cold Spring Harbor, NY 11724, USA
| | - Fatih Mercan
- Cold Spring Harbor Laboratory, 1 Bungtown Road, Cold Spring Harbor, NY 11724, USA
| | - Keith Rivera
- Cold Spring Harbor Laboratory, 1 Bungtown Road, Cold Spring Harbor, NY 11724, USA
| | - Darryl J Pappin
- Cold Spring Harbor Laboratory, 1 Bungtown Road, Cold Spring Harbor, NY 11724, USA
| | - Christopher R Vakoc
- Cold Spring Harbor Laboratory, 1 Bungtown Road, Cold Spring Harbor, NY 11724, USA.
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30
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Interaction of c-Myb with p300 is required for the induction of acute myeloid leukemia (AML) by human AML oncogenes. Blood 2014; 123:2682-90. [DOI: 10.1182/blood-2012-02-413187] [Citation(s) in RCA: 88] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Key Points
A mutation preventing interaction between c-Myb and p300 prevents transformation and leukemia induction by MLL-AF9 and AML1-ETO9a oncogenes. Identifying agents that block the c-Myb-p300 interaction may be a valuable approach to developing a therapy for acute myeloid leukemia.
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31
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Pieraccioli M, Imbastari F, Antonov A, Melino G, Raschellà G. Activation of miR200 by c-Myb depends on ZEB1 expression and miR200 promoter methylation. Cell Cycle 2014; 12:2309-20. [PMID: 24067373 DOI: 10.4161/cc.25405] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Tumor progression to metastasis is a complex, sequential process that requires proliferation, resistance to apoptosis, motility and invasion to colonize at distant sites. The acquisition of these features implies a phenotypic plasticity by tumor cells that must adapt to different conditions by modulating several signaling pathways (1) during the journey to the final site of metastasis. Several transcription factors and microRNA play a role in tumor progression, but less is known about the control of their expression during this process. Here, we demonstrate by ectopic expression and gene silencing that the proto-oncogene c-Myb activates the expression of the 5 members of miR200 family (miR200b, miR200a, miR429, miR200c and miR141) that are involved in the control of epithelial-mesenchymal transition (EMT) and metastasis in many types of cancers. Transcriptional activation of miR200 by c-Myb occurs through binding to myb binding sites located in the promoter regions of miR200 genes on human chromosomes 1 and 12. Furthermore, when c-Myb and the transcriptional repressor ZEB1 are co-expressed, as at the onset EMT, the repression by ZEB1 prevails over the activation by c-Myb, and the expression of miR200 is inhibited. We also demonstrate that during EMT induced by TGF-β, the promoters of miR200 genes are methylated, and their transcription is repressed regardless of the presence of repressors such as ZEB1 and activators such as c-Myb. Finally, we find a correlation between the expression of c-Myb and that of four out of 5 miR200 in a data set of 207 breast cancer patients.
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Affiliation(s)
- Marco Pieraccioli
- ENEA Research Center Casaccia, Radiation Biology and Human Health Unit, Rome, Italy
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32
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Bies J, Sramko M, Wolff L. Stress-induced phosphorylation of Thr486 in c-Myb by p38 mitogen-activated protein kinases attenuates conjugation of SUMO-2/3. J Biol Chem 2013; 288:36983-93. [PMID: 24257756 DOI: 10.1074/jbc.m113.500264] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
c-Myb plays an essential role in regulation of properly balanced hematopoiesis through transcriptional regulation of genes directly controlling cellular processes such as proliferation, differentiation, and apoptosis. The transcriptional activity and protein levels of c-Myb are strictly controlled through post-translational modifications such as phosphorylation, acetylation, ubiquitination, and SUMOylation. Conjugation of small ubiquitin-like modifier (SUMO) proteins has been shown to suppress the transcriptional activity of c-Myb. SUMO-1 modifies c-Myb under physiological conditions, whereas SUMO-2/3 conjugation was reported in cells under stress. Because stress also activates several cellular protein kinases, we investigated whether phosphorylation of c-Myb changes in stressed cells and whether a mutual interplay exists between phosphorylation and SUMOylation of c-Myb. Here we show that several types of environmental stress induce a rapid change in c-Myb phosphorylation. Interestingly, the phosphorylation of Thr(486), located in close proximity to SUMOylation site Lys(499) of c-Myb, is detected preferentially in nonSUMOylated protein and has a negative effect on stress-induced SUMOylation of c-Myb. Stress-activated p38 MAPKs phosphorylate Thr(486) in c-Myb, attenuate its SUMOylation, and increase its proteolytic turnover. Stressed cells expressing a phosphorylation-deficient T486A mutant demonstrate decreased expression of c-Myb target genes Bcl-2 and Bcl-xL and accelerated apoptosis because of increased SUMOylation of the mutant protein. These results suggest that phosphorylation-dependent modulation of c-Myb SUMOylation may be important for proper response of cells to stress. In summary, we have identified a novel regulatory interplay between phosphorylation and SUMOylation of c-Myb that regulates its activity in stressed cells.
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Affiliation(s)
- Juraj Bies
- From the Laboratory of Cellular Oncology, Center for Cancer Research, NCI, National Institutes of Health, Bethesda, Maryland 20892
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Proteome changes induced by c-myb silencing in human chronic myeloid leukemia cells suggest molecular mechanisms and putative biomarkers of hematopoietic malignancies. J Proteomics 2013; 96:200-22. [PMID: 24220303 DOI: 10.1016/j.jprot.2013.10.040] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2013] [Revised: 10/18/2013] [Accepted: 10/30/2013] [Indexed: 11/23/2022]
Abstract
UNLABELLED To shed light on the molecular mechanisms associated with aberrant accumulation of c-Myb in chronic myeloid leukemia, comparative proteomic analysis was performed on c-myb RNAi-specifically silenced K562 cells, sampled on a time-course basis. 2D-DIGE technology highlighted 37 differentially-represented proteins that were further characterized by nLC-ESI-LIT-MS/MS and validated by western blotting and qRT-PCR analysis. Most of the deregulated proteins were related to protein folding, energy/primary metabolism, transcription/translation regulation and oxidative stress response. Protein network analysis suggested that glycolysis, gluconeogenesis and protein ubiquitination biosynthesis pathways were highly represented, confirming also the pivotal role of c-Myc. A specific reduced representation was observed for glyceraldehyde-3-phosphate-dehydrogenase and α-enolase, suggesting a possible role of c-Myb in the activation of aerobic glycolysis. A reduced amount was also observed for stress responsive heat shock 70kDa protein and 78kDa glucose-regulated protein, previously identified as direct targets of c-Myb. Among over-represented proteins, worth mentioning is the chromatin modifier chromobox protein homolog 3 that contributes to silencing of E2F- and Myc-responsive genes in quiescent G0 cells. Data here presented, while providing novel insights onto the molecular mechanisms underlying c-Myb activity, indicate potential protein biomarkers for monitoring the progression of chronic myeloid leukemia. BIOLOGICAL SIGNIFICANCE Myeloid leukemia is a malignant disease of the hematopoietic system in which cells of myeloid lineages accumulate to an undifferentiated state. In particular, it was shown that an aberrant accumulation of the c-Myb transcriptional factor is associated with the suppression of normal differentiation processes promoting the development of the hematopoietic malignancies. Many efforts have been recently made to identify novel genes directly targeted by c-Myb at a transcriptome level. In this work, we originally describe a differential proteomic approach to facilitate the comprehension of the regulation of the protein networks exerted by c-Myb. Our study reveals a complex network of proteins regulated by c-Myb. The functional heterogeneity of these proteins emphasizes the pleiotropic role of c-Myb as a regulator of genes that are crucial for energy production and stress response in leukemia. In fact, variations in glyceraldehyde-3-phosphate-dehydrogenase and α-enolase suggest a possible role of c-Myb in the activation of aerobic glycolysis. Moreover, significant differences were found for heat shock 70kDa protein and 78kDa glucose-regulated protein known as direct c-Myb targets. This work highlights potential protein biomarkers to look into disease progression and to develop translational medicine approaches in myeloid leukemia.
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von Holstein SL. Tumours of the lacrimal gland. Epidemiological, clinical and genetic characteristics. Acta Ophthalmol 2013; 91 Thesis 6:1-28. [PMID: 24893972 DOI: 10.1111/aos.12271] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Tumours of the lacrimal gland are rare, but the prognosis may be grave. To date, no population-based incidence and distribution data on lacrimal gland tumours exist. In addition, almost nothing is known about the genetic profile of epithelial tumours of the lacrimal gland. We collected specimens and clinical files on all biopsied lacrimal gland lesions in Denmark over a 34-year period and re-evaluated the diagnosis to provide updated population-based incidence rates and epidemiological characteristics. Clinical data regarding symptoms, clinical examinations, treatment and follow-up were collected for patients with adenoid cystic carcinoma (ACC), pleomorphic adenoma (PA), carcinoma ex pleomorphic adenoma (Ca-ex-PA) and mucoepidermoid carcinoma (MEC). Using RT-PCR, FISH, immunohistochemistry, Q-PCR and high-resolution array-based comparative genomic hybridization (arrayCGH) we explored the genetic characteristics including copy number alterations (CNA) in ACC, PA, Ca-ex-PA and MEC. The incidence of biopsied lacrimal gland lesions was 1.3/1,000,000/year, and ~50% were neoplastic lesions. Of these, 55% were malignant tumours with epithelial tumours as the most frequent. The overall incidence was increasing, and this was caused by an increase in biopsied non-neoplastic lesions. We found that 10/14 ACCs either expressed the MYB-NFIB fusion gene and/or had rearrangements of MYB. All ACCs expressed the MYB protein. ACC was characterized by recurrent copy number losses involving 6q, 12q and 17q and gains involving 19q, 8q and 11q. ArrayCGH revealed an apparently normal genomic profile in 11/19 PAs. The remaining 8 PAs had recurrent copy number losses involving 1p, 6q, 8q and 13q and gain involving 9p. PA expressed PLAG1 in all tumours whereas only 2/29 tumours expressed HMGA2. Ca-ex-PA was characterized by recurrent copy number gain involving 22q. PLAG1 was expressed in 3/5 Ca-ex-PA whereas none of these tumours expressed HMGA2. MEC expressed the CRTC1-MAML2, and this fusion was found to be tumour-specific for lacrimal gland MEC. In conclusion, lacrimal gland lesions that require pathological evaluation are rare in the Danish population, and the incidence rate of biopsied benign lesions is increasing. Epithelial tumours of the lacrimal gland are molecularly very similar to their salivary gland counterparts in the expression of the tumour-specific fusion genes and in their genomic imbalances as demonstrated by arrayCGH. MYB-NFIB is a useful biomarker for ACC and MYB, and its downstream target genes may be potential therapeutic targets for these tumours.
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Ye P, Zhao L, Gonda TJ. The MYB oncogene can suppress apoptosis in acute myeloid leukemia cells by transcriptional repression of DRAK2 expression. Leuk Res 2013; 37:595-601. [PMID: 23398943 DOI: 10.1016/j.leukres.2013.01.012] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2012] [Revised: 01/14/2013] [Accepted: 01/16/2013] [Indexed: 11/19/2022]
Abstract
RNA interference-mediated suppression of MYB expression promoted apoptosis in the AML cell line U937, without affecting expression of the anti-apoptotic MYB target BCL2. This was accompanied by up-regulation of the pro-apoptotic gene DRAK2 and stimulation of caspase-9 activity. Moreover, RNA interference-mediated suppression of DRAK2 in U937 cells alleviated apoptosis induced by MYB down-regulation. Finally ChIP assays showed that in U937 cells MYB binds to a conserved element upstream of the DRAK2 transcription start site. Together, these findings identify a novel mechanism by which MYB suppresses apoptosis in an AML model cell line.
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Affiliation(s)
- Ping Ye
- School of Pharmacy, The University of Queensland, Brisbane, Queensland, Australia
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Sarvaiya PJ, Schwartz JR, Hernandez CP, Rodriguez PC, Vedeckis WV. Role of c-Myb in the survival of pre B-cell acute lymphoblastic leukemia and leukemogenesis. Am J Hematol 2012; 87:969-76. [PMID: 22764095 DOI: 10.1002/ajh.23283] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2012] [Revised: 05/10/2012] [Accepted: 05/22/2012] [Indexed: 12/26/2022]
Abstract
Acute lymphoblastic leukemia (ALL) is the most common cancer in children. The current treatment protocol for ALL involves an intense chemotherapy regimen yielding cure rates of nearly 80%. However, new therapies need to be designed not only to increase the survival rate but also to combat the risk of severe therapy associated toxicities including secondary malignancies, growth problems, organ damage, and infertility. The c-Myb proto-oncogene is highly expressed in immature hematopoietic cells. In this study, we demonstrate that loss of c-Myb itself decreased the viability of these leukemic cells. Additionally, the inhibition of c-Myb caused a decrease in cell proliferation, significantly increased the number of cells in G(0) /G(1) phase of the cell cycle, increased the sensitivity of pre-B-ALL cells to cytotoxic agents in vitro, and significantly delayed disease onset in a mouse model of leukemia. Furthermore, we demonstrate that Bcl-2 is a target of c-Myb in pre-B-ALL cells. Our results identify c-Myb as a potential therapeutic target in pre-B-ALL and suggest that suppression of c-Myb levels or activity, in combination with currently used therapies and/or dose reduction, may lead to a decrease in toxicity and an increase in patient survival rates. Because c-Myb is aberrantly expressed in several other malignancies, targeting c-Myb will have broad clinical applications.
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Affiliation(s)
- Purvaba J Sarvaiya
- Department of Biochemistry and Molecular Biology, Louisiana State University Health Sciences Center, New Orleans, LA, USA
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Liu D, Shi M, Zhang H, Qian L, Yu M, Hu M, Zhang R, Wang T, Han C, Duan H, Guo N. c-Myb regulates cell cycle-dependent expression of Erbin: an implication for a novel function of Erbin. PLoS One 2012; 7:e42903. [PMID: 22880131 PMCID: PMC3413663 DOI: 10.1371/journal.pone.0042903] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2012] [Accepted: 07/12/2012] [Indexed: 11/23/2022] Open
Abstract
In the present study, we demonstrated the cell cycle periodicity of Erbin expression with the maximal expression of Erbin in G2/M phase. A significant increase in Erbin promoter activity was observed in G2/M phase-synchronized cells. Sequence analysis revealed a c-Myb site in the core promoter region of Erbin. Mutagenesis of c-Myb consensus sequences abrogated the increased Erbin promoter activity in G2/M phase. ChIP and oligonucleotide pull-down assays validated that the recruitment of c-Myb to the consensus sequences was specific. The interaction of c-Myb with c-Myb site in the Erbin promoter was significantly enhanced in G2/M phase. Ectopic overexpression of c-Myb led to the up-regulation of Erbin promoter activity and c-Myb silencing by small interfering RNA significantly decreased Erbin protein level. Transfection of c-Myb rescued Erbin expression that was impaired by c-Myb knockdown. It proves that c-Myb and the c-Myb response element mediate the cell cycle-dependent expression of Erbin. Inactivation of Erbin causes an acceleration of the G1/S transition, the formation of multipolar spindles and abnormal chromosome congression. These results unravel a critical role of c-Myb in promoting Erbin transcription in G2/M phase and also predict an unappreciated function of Erbin in cell cycle progression.
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Affiliation(s)
- Dan Liu
- Department of Pathology, Hebei Medical University, Shijiazhuang, People's Republic of China
| | - Ming Shi
- Department of Pathophysiology, Institute of Basic Medical Sciences, Beijing, People's Republic of China
| | - Hao Zhang
- Department of Pathophysiology, Institute of Basic Medical Sciences, Beijing, People's Republic of China
| | - Lu Qian
- Department of Pathophysiology, Institute of Basic Medical Sciences, Beijing, People's Republic of China
| | - Ming Yu
- Department of Pathophysiology, Institute of Basic Medical Sciences, Beijing, People's Republic of China
| | - Meiru Hu
- Department of Pathophysiology, Institute of Basic Medical Sciences, Beijing, People's Republic of China
| | - Ruihong Zhang
- Department of Pathology, Hebei Medical University, Shijiazhuang, People's Republic of China
| | - Tianyou Wang
- Capital Institute of Pediatrics, Beijing, People's Republic of China
| | - Caili Han
- Department of Pathology, Hebei Medical University, Shijiazhuang, People's Republic of China
| | - Huijun Duan
- Department of Pathology, Hebei Medical University, Shijiazhuang, People's Republic of China
- * E-mail: (HD); (NG)
| | - Ning Guo
- Department of Pathophysiology, Institute of Basic Medical Sciences, Beijing, People's Republic of China
- * E-mail: (HD); (NG)
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Manzotti G, Mariani SA, Corradini F, Bussolari R, Cesi V, Vergalli J, Ferrari-Amorotti G, Fragliasso V, Soliera AR, Cattelani S, Raschellà G, Holyoake TL, Calabretta B. Expression of p89(c-Mybex9b), an alternatively spliced form of c-Myb, is required for proliferation and survival of p210BCR/ABL-expressing cells. Blood Cancer J 2012; 2:e71. [PMID: 22829973 PMCID: PMC3366069 DOI: 10.1038/bcj.2012.16] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2012] [Accepted: 04/05/2012] [Indexed: 01/04/2023] Open
Abstract
The c-Myb gene encodes the p75c-Myb isoform and less-abundant proteins generated by alternatively spliced transcripts. Among these, the best known is pc-Mybex9b, which contains 121 additional amino acids between exon 9 and 10, in a domain involved in protein–protein interactions and negative regulation. In hematopoietic cells, expression of pc-Mybex9b accounts for 10–15% of total c-Myb; these levels may be biologically relevant because modest changes in c-Myb expression affects proliferation and survival of leukemic cells and lineage choice and frequency of normal hematopoietic progenitors. In this study, we assessed biochemical activities of pc-Mybex9b and the consequences of perturbing its expression in K562 and primary chronic myeloid leukemia (CML) progenitor cells. Compared with p75c-Myb, pc-Mybex9b is more stable and more effective in transactivating Myb-regulated promoters. Ectopic expression of pc-Mybex9b enhanced proliferation and colony formation and reduced imatinib (IM) sensitivity of K562 cells; conversely, specific downregulation of pc-Mybex9b reduced proliferation and colony formation, enhanced IM sensitivity of K562 cells and markedly suppressed colony formation of CML CD34+ cells, without affecting the levels of p75c-Myb. Together, these studies indicate that expression of the low-abundance pc-Mybex9b isoform has an important role for the overall biological effects of c-Myb in BCR/ABL-transformed cells.
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Srivastava SK, Bhardwaj A, Singh S, Arora S, McClellan S, Grizzle WE, Reed E, Singh AP. Myb overexpression overrides androgen depletion-induced cell cycle arrest and apoptosis in prostate cancer cells, and confers aggressive malignant traits: potential role in castration resistance. Carcinogenesis 2012; 33:1149-57. [PMID: 22431717 DOI: 10.1093/carcin/bgs134] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Myb, a cellular progenitor of v-Myb oncogenes, is amplified in prostate cancer and exhibits greater amplification frequency in hormone-refractory disease. Here, we have investigated the functional significance of Myb in prostate cancer. Our studies demonstrate Myb expression in all prostate cancer cell lines (LNCaP, C4-2, PC3 and DU145) examined, whereas it is negligibly expressed in normal/benign prostate epithelial cells (RWPE1 and RWPE2). Notably, Myb is significantly upregulated, both at transcript (>60-fold) and protein (>15-fold) levels, in castration-resistant (C4-2) cells as compared with androgen-dependent (LNCaP) prostate cancer cells of the same genotypic lineage. Using loss and gain of function approaches, we demonstrate that Myb promotes and sustains cell cycle progression and survival under androgen-supplemented and -deprived conditions, respectively, through induction of cyclins (A1, D1 and E1), Bcl-xL and Bcl2 and downregulation of p27 and Bax. Interestingly, Myb overexpression is also associated with enhanced prostate-specific antigen expression. Furthermore, our data show a role of Myb in enhanced motility and invasion and decreased homotypic interactions of prostate cancer cells. Myb overexpression is also associated with actin reorganization leading to the formation of filopodia-like cellular protrusions. Immunoblot analyses demonstrate gain of mesenchymal and loss of epithelial markers and vice versa, in Myb-overexpressing LNCaP and -silenced C4-2 cells, respectively, indicating a role of Myb in epithelial to mesenchymal transition. Altogether, our studies provide first experimental evidence for a functional role of Myb in growth and malignant behavior of prostate cancer cells and suggest a novel mechanism for castration resistance.
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Affiliation(s)
- Sanjeev K Srivastava
- Department of Oncologic Sciences, Mitchell Cancer Institute, University of South Alabama, Mobile, AL 36604-1405, USA
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Bujnicki T, Wilczek C, Schomburg C, Feldmann F, Schlenke P, Müller-Tidow C, Schmidt TJ, Klempnauer KH. Inhibition of Myb-dependent gene expression by the sesquiterpene lactone mexicanin-I. Leukemia 2011; 26:615-22. [PMID: 21986841 DOI: 10.1038/leu.2011.275] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The c-myb proto-oncogene encodes a transcription factor that is highly expressed in the progenitor cells of the hematopoietic system, where it regulates the expression of genes important for lineage determination, cell proliferation and differentiation. There is strong evidence that deregulation of c-myb expression is involved in the development of human tumors, particularly of certain types of leukemia, and breast and colon cancer. The c-Myb protein is therefore an interesting therapeutic target. Here, we have investigated the potential of natural sesquiterpene lactones (STLs), a class of compounds that are active constituents of a variety of medicinal plants, to suppress Myb-dependent gene expression. We have developed a test system that allows screening of compounds for their ability to interfere with the activation of Myb target genes. Using this assay system, we have identified the STL mexicanin-I as the first cell-permeable, low-molecular-weight inhibitor of Myb-induced gene expression.
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Affiliation(s)
- T Bujnicki
- Institute for Biochemistry, Westfälische-Wilhelms-Universität, Münster, Germany
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Waldron T, De Dominici M, Soliera AR, Audia A, Iacobucci I, Lonetti A, Martinelli G, Zhang Y, Martinez R, Hyslop T, Bender TP, Calabretta B. c-Myb and its target Bmi1 are required for p190BCR/ABL leukemogenesis in mouse and human cells. Leukemia 2011; 26:644-53. [PMID: 21960247 PMCID: PMC3252490 DOI: 10.1038/leu.2011.264] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Expression of c-Myb is required for normal hematopoiesis and for proliferation of myeloid leukemia blasts and a subset of T cell leukemia but its role in B-cell leukemogenesis is unknown. We tested the role of c-Myb in p190BCR/ABL-dependent B-cell leukemia in mice transplanted with p190BCR/ABL-transduced marrow cells with a c-Myb allele (Mybf/d) and in double transgenic p190BCR/ABL/Mybw/d mice. In both models, loss of a c-Myb allele caused a less aggressive B-cell leukemia. In p190BCR/ABL expressing human B-cell leukemia lines, knockdown of c-Myb expression suppressed proliferation and colony formation. Compared to c-Mybw/f cells, expression of Bmi1, a regulator of stem cell proliferation and maintenance, was decreased in pre-B cells from Mybw/d p190BCR/ABL transgenic mice. Ectopic expression of a mutant c-Myb or Bmi1 enhanced the proliferation and colony formation of Mybw/d p190BCR/ABL B-cells; by contrast, Bmi1 downregulation inhibited colony formation of p190BCR/ABL-expressing murine B cells and human B-cell leukemia lines. Moreover, c-Myb interacted with a segment of the human Bmi1 promoter and enhanced its activity. In blasts from nineteen Ph1 adult ALL patients, levels of c-Myb and Bmi1 showed a positive correlation. Together, these findings support the existence of a c-Myb-Bmi1 transcription regulatory pathway required for p190BCR/ABL leukemogenesis.
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Affiliation(s)
- T Waldron
- Department of Cancer Biology and Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA 19107, USA
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Molecular predictors of response to decitabine in advanced chronic myelomonocytic leukemia: a phase 2 trial. Blood 2011; 118:3824-31. [PMID: 21828134 DOI: 10.1182/blood-2011-05-352039] [Citation(s) in RCA: 164] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Hydroxyurea is the standard therapy of chronic myelomonocytic leukemia (CMML) presenting with advanced myeloproliferative and/or myelodysplastic features. Response to hypomethylating agents has been reported in heterogeneous series of CMML. We conducted a phase 2 trial of decitabine (DAC) in 39 patients with advanced CMML defined according to a previous trial. Median number of DAC cycles was 10 (range, 1-24). Overall response rate was 38% with 4 complete responses (10%), 8 marrow responses (21%), and 3 stable diseases with hematologic improvement (8%). Eighteen patients (46%) demonstrated stable disease without hematologic improvement, and 6 (15%) progressed to acute leukemia. With a median follow-up of 23 months, overall survival was 48% at 2 years. Mutations in ASXL1, TET2, AML1, NRAS, KRAS, CBL, FLT3, and janus kinase 2 (JAK2) genes, and hypermethylation of the promoter of the tumor suppressor gene TIF1γ, did not predict response or survival on DAC therapy. Lower CJUN and CMYB gene expression levels independently predicted improved overall survival. This trial confirmed DAC efficacy in approximately 40% of CMML patients with advanced myeloproliferative or myelodysplastic features and suggested that CJUN and CMYB expression could be potential biomarkers in this setting. This trial is registered at EudraCT (eudract.ema.europa.eu) as #2008-000470-21 and www.clinicaltrials.gov as #NCT01098084.
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Zhou Y, Ness SA. Myb proteins: angels and demons in normal and transformed cells. Front Biosci (Landmark Ed) 2011; 16:1109-31. [PMID: 21196221 DOI: 10.2741/3738] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
A key regulator of proliferation, differentiation and cell fate, the c-Myb transcription factor regulates the expression of hundreds of genes and is in turn regulated by numerous pathways and protein interactions. However, the most unique feature of c-Myb is that it can be converted into an oncogenic transforming protein through a few mutations that completely change its activity and specificity. The c-Myb protein is a myriad of interactions and activities rolled up in a protein that controls proliferation and differentiation in many different cell types. Here we discuss the background and recent progress that have led to a better understanding of this complex protein, and outline the questions that have yet to be answered.
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Affiliation(s)
- Ye Zhou
- Department of Molecular Genetics and Microbiology, University of New Mexico Health Sciences Center, Albuquerque, NM 87131-0001, USA
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Thorner AR, Parker JS, Hoadley KA, Perou CM. Potential tumor suppressor role for the c-Myb oncogene in luminal breast cancer. PLoS One 2010; 5:e13073. [PMID: 20949095 PMCID: PMC2951337 DOI: 10.1371/journal.pone.0013073] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2010] [Accepted: 09/04/2010] [Indexed: 11/19/2022] Open
Abstract
Background The transcription factor c-Myb has been well characterized as an oncogene in several human tumor types, and its expression in the hematopoietic stem/progenitor cell population is essential for proper hematopoiesis. However, the role of c-Myb in mammopoeisis and breast tumorigenesis is poorly understood, despite its high expression in the majority of breast cancer cases (60–80%). Methodology/Principal Findings We find that c-Myb high expression in human breast tumors correlates with the luminal/ER+ phenotype and a good prognosis. Stable RNAi knock-down of endogenous c-Myb in the MCF7 luminal breast tumor cell line increased tumorigenesis both in vitro and in vivo, suggesting a possible tumor suppressor role in luminal breast cancer. We created a mammary-derived c-Myb expression signature, comprised of both direct and indirect c-Myb target genes, and found it to be highly correlated with a published mature luminal mammary cell signature and least correlated with a mammary stem/progenitor lineage gene signature. Conclusions/Significance These data describe, for the first time, a possible tumor suppressor role for the c-Myb proto-oncogene in breast cancer that has implications for the understanding of luminal tumorigenesis and for guiding treatment.
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Affiliation(s)
- Aaron R. Thorner
- Curriculum in Genetics and Molecular Biology, University of North Carolina, Chapel Hill, North Carolina, United States of America
- Department of Genetics, University of North Carolina, Chapel Hill, North Carolina, United States of America
- Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, North Carolina, United States of America
| | - Joel S. Parker
- Curriculum in Genetics and Molecular Biology, University of North Carolina, Chapel Hill, North Carolina, United States of America
- Department of Genetics, University of North Carolina, Chapel Hill, North Carolina, United States of America
- Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, North Carolina, United States of America
| | - Katherine A. Hoadley
- Department of Genetics, University of North Carolina, Chapel Hill, North Carolina, United States of America
- Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, North Carolina, United States of America
| | - Charles M. Perou
- Department of Genetics, University of North Carolina, Chapel Hill, North Carolina, United States of America
- Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, North Carolina, United States of America
- Department of Pathology and Laboratory Medicine, University of North Carolina, Chapel Hill, North Carolina, United States of America
- * E-mail:
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Pattabiraman DR, Sun J, Dowhan DH, Ishii S, Gonda TJ. Mutations in Multiple Domains of c-Myb Disrupt Interaction with CBP/p300 and Abrogate Myeloid Transforming Ability. Mol Cancer Res 2009; 7:1477-86. [DOI: 10.1158/1541-7786.mcr-09-0070] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Gonda TJ, Leo P, Ramsay RG. Estrogen and MYB in breast cancer: potential for new therapies. Expert Opin Biol Ther 2008; 8:713-7. [PMID: 18476782 DOI: 10.1517/14712598.8.6.713] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
MYB is highly expressed in almost all estrogen receptor (ER)-positive breast tumours and is a direct target of estrogen/ER signalling. Our recent studies have shown that MYB is also required for the proliferation of ER-positive breast tumour cell lines, and have shed further light on the mechanism of ER regulation of MYB expression. Here we discuss the rationale for therapeutic targeting of MYB in breast cancer and consider a number of approaches to developing an anti-MYB therapeutic.
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Affiliation(s)
- Thomas J Gonda
- Professorial Research Fellow, Deputy Director and Head Cancer Biology Program, University of Queensland Diamantina Institute for Cancer, Immunology and Metabolic Medicine, Princess Alexandra Hospital, Woolloongabba, Queensland, Australia.
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Abstract
It is now common knowledge that for a solid tumour to become life-threatening clinically, an adequate blood supply to the neoplasm has to be established. Although neovascularisation via angiogenesis leads to a subsequent rapid growth of the tumour mass, it provides the most reliable route by which neoplastic cells may be reached by cytotoxics. In addition, for a majority of tumours, the lesion's vasculature is more permeable and tortuous than that of the surrounding healthy host tissue. Such deviation potentiates selective delivery of drugs to be achieved. This review examines, from various viewpoints, the area of tumour angiogenesis and vascularisation, currently one of the most fertile and active fields of cancer research.
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49
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Dass CR, Walker TL, Decruz EE, Burton MA. Cationic Liposomes and Gene Therapy for Solid Tumors. Drug Deliv 2008. [DOI: 10.3109/10717549709051887] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Abstract
The transcription factor MYB has a key role as a regulator of stem and progenitor cells in the bone marrow, colonic crypts and a neurogenic region of the adult brain. It is in these compartments that a deficit in MYB activity leads to severe or lethal phenotypes. As was predicted from its leukaemogenicity in several animal species, MYB has now been identified as an oncogene that is involved in some human leukaemias. Moreover, recent evidence has strengthened the case that MYB is activated in colon and breast cancer: a block to MYB expression is overcome by mutation of the regulatory machinery in the former disease and by oestrogen receptor-alpha (ERalpha) in the latter.
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Affiliation(s)
- Robert G Ramsay
- Peter MacCallum Cancer Centre, St Andrew's Place, Melbourne, Victoria 3002, Australia
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