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Day RB, Hickman JA, Xu Z, Katerndahl CD, Ferraro F, Ramakrishnan SM, Erdmann-Gilmore P, Sprung RW, Mi Y, Townsend RR, Miller CA, Ley TJ. Proteogenomic analysis reveals cytoplasmic sequestration of RUNX1 by the acute myeloid leukemia-initiating CBFB::MYH11 oncofusion protein. J Clin Invest 2023; 134:e176311. [PMID: 38061017 PMCID: PMC10866659 DOI: 10.1172/jci176311] [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: 10/10/2023] [Accepted: 12/06/2023] [Indexed: 02/16/2024] Open
Abstract
Several canonical translocations produce oncofusion genes that can initiate acute myeloid leukemia (AML). Although each translocation is associated with unique features, the mechanisms responsible remain unclear. While proteins interacting with each oncofusion are known to be relevant for how they act, these interactions have not yet been systematically defined. To address this issue in an unbiased fashion, we fused a promiscuous biotin ligase (TurboID) in-frame with 3 favorable-risk AML oncofusion cDNAs (PML::RARA, RUNX1::RUNX1T1, and CBFB::MYH11) and identified their interacting proteins in primary murine hematopoietic cells. The PML::RARA- and RUNX1::RUNX1T1-TurboID fusion proteins labeled common and unique nuclear repressor complexes, implying their nuclear localization. However, CBFB::MYH11-TurboID-interacting proteins were largely cytoplasmic, probably because of an interaction of the MYH11 domain with several cytoplasmic myosin-related proteins. Using a variety of methods, we showed that the CBFB domain of CBFB::MYH11 sequesters RUNX1 in cytoplasmic aggregates; these findings were confirmed in primary human AML cells. Paradoxically, CBFB::MYH11 expression was associated with increased RUNX1/2 expression, suggesting the presence of a sensor for reduced functional RUNX1 protein, and a feedback loop that may attempt to compensate by increasing RUNX1/2 transcription. These findings may have broad implications for AML pathogenesis.
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Affiliation(s)
- Ryan B. Day
- Section of Stem Cell Biology, Division of Oncology, Department of Internal Medicine, and
| | - Julia A. Hickman
- Section of Stem Cell Biology, Division of Oncology, Department of Internal Medicine, and
| | - Ziheng Xu
- Section of Stem Cell Biology, Division of Oncology, Department of Internal Medicine, and
| | - Casey D.S. Katerndahl
- Section of Stem Cell Biology, Division of Oncology, Department of Internal Medicine, and
| | - Francesca Ferraro
- Section of Stem Cell Biology, Division of Oncology, Department of Internal Medicine, and
| | | | - Petra Erdmann-Gilmore
- Division of Endocrinology, Metabolism and Lipid Research, Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Robert W. Sprung
- Division of Endocrinology, Metabolism and Lipid Research, Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Yiling Mi
- Division of Endocrinology, Metabolism and Lipid Research, Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
| | - R. Reid Townsend
- Division of Endocrinology, Metabolism and Lipid Research, Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Christopher A. Miller
- Section of Stem Cell Biology, Division of Oncology, Department of Internal Medicine, and
| | - Timothy J. Ley
- Section of Stem Cell Biology, Division of Oncology, Department of Internal Medicine, and
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Xu J, Zhang Z, Shen D, Zhang T, Zhang J, De W. Long noncoding RNA LINC01296 plays an oncogenic role in colorectal cancer by suppressing p15 expression. J Int Med Res 2021; 49:3000605211004414. [PMID: 33983053 PMCID: PMC8127761 DOI: 10.1177/03000605211004414] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
OBJECTIVE To examine the role of the long noncoding RNA LINC01296 in colorectal carcinoma (CRC) and to explore the underlying mechanism. METHODS We detected LINC01296 expression levels in a cohort of 51 paired CRC and normal tissues. We also assessed the effects of LINC01296 on cell proliferation and apoptosis in CRC cells in vitro, and measured its effect on tumor growth in an in vivo mouse model. We identified the potential downstream targets of LINC01296 and assessed its regulatory effects. RESULTS Expression levels of LINC01296 were elevated in 37/51 CRC tissues compared with the corresponding normal tissues and were significantly associated with tumor stage, lymph node metastasis, and distant metastasis. Knockdown of LINC01296 using antisense oligonucleotides inhibited cell proliferation and promoted apoptosis of colon cancer cells in vitro and inhibited tumor growth in vivo. Knockdown of LINC01296 also significantly increased the gene expression of p15 in colon cancer cells. LINC01296-specific suppression of p15 was validated by the interaction between enhancer of zeste homolog 2 and LINC01296. CONCLUSION Overexpression of LINC01296 suppressed the expression of p15 leading to CRC carcinogenesis. These findings may provide the basis for novel future CRC-targeted therapies.
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Affiliation(s)
- Jianing Xu
- Department of Biochemistry and Molecular Biology, Nanjing Medical University, Nanjing, Jiangsu, China.,Department of Emergency Medicine, Jiangyin People's Hospital, Jiangyin, Jiangsu, China
| | - Zhehao Zhang
- Department of Biochemistry and Molecular Biology, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Dong Shen
- Department of Oncology, Jiangyin People's Hospital, Jiangyin, Jiangsu, China
| | - Ting Zhang
- Department of Oncology, Jiangyin People's Hospital, Jiangyin, Jiangsu, China
| | - Jinsong Zhang
- Department of Emergency Medicine, the First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, China
| | - Wei De
- Department of Biochemistry and Molecular Biology, Nanjing Medical University, Nanjing, Jiangsu, China
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Quiescence of adult oligodendrocyte precursor cells requires thyroid hormone and hypoxia to activate Runx1. Sci Rep 2017; 7:1019. [PMID: 28432293 PMCID: PMC5430791 DOI: 10.1038/s41598-017-01023-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2016] [Accepted: 03/23/2017] [Indexed: 12/15/2022] Open
Abstract
The adult mammalian central nervous system (CNS) contains a population of slowly dividing oligodendrocyte precursor cells (OPCs), i.e., adult OPCs, which supply new oligodendrocytes throughout the life of animal. While adult OPCs develop from rapidly dividing perinatal OPCs, the mechanisms underlying their quiescence remain unknown. Here, we show that perinatal rodent OPCs cultured with thyroid hormone (TH) under hypoxia become quiescent and acquire adult OPCs-like characteristics. The cyclin-dependent kinase inhibitor p15/INK4b plays crucial roles in the TH-dependent cell cycle deceleration in OPCs under hypoxia. Klf9 is a direct target of TH-dependent signaling. Under hypoxic conditions, hypoxia-inducible factors mediates runt-related transcription factor 1 activity to induce G1 arrest in OPCs through enhancing TH-dependent p15/INK4b expression. As adult OPCs display phenotypes of adult somatic stem cells in the CNS, the current results shed light on environmental requirements for the quiescence of adult somatic stem cells during their development from actively proliferating stem/progenitor cells.
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Momparler RL, Côté S, Momparler LF, Idaghdour Y. Inhibition of DNA and Histone Methylation by 5-Aza-2'-Deoxycytidine (Decitabine) and 3-Deazaneplanocin-A on Antineoplastic Action and Gene Expression in Myeloid Leukemic Cells. Front Oncol 2017; 7:19. [PMID: 28261562 PMCID: PMC5309231 DOI: 10.3389/fonc.2017.00019] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2016] [Accepted: 01/31/2017] [Indexed: 12/26/2022] Open
Abstract
Epigenetic alterations play an important role in the development of acute myeloid leukemia (AML) by silencing of genes that suppress leukemogenesis and differentiation. One of the key epigenetic changes in AML is gene silencing by DNA methylation. The importance of this alteration is illustrated by the induction of remissions in AML by 5-aza-2′-deoxycytidine (5-AZA-CdR, decitabine), a potent inhibitor of DNA methylation. However, most patients induced into remission by 5-AZA-CdR will relapse, suggesting that a second agent should be sought to increase the efficacy of this epigenetic therapy. An interesting candidate for this purpose is 3-deazaneplanocin A (DZNep). This analog inhibits EZH2, a histone methyltransferase that trimethylates lysine 27 histone H3 (H3K27me3), a marker for gene silencing. This second epigenetic silencing mechanism also plays an important role in leukemogenesis as shown in preclinical studies where DZNep exhibits potent inhibition of colony formation by AML cells. We reported previously that 5-AZA-CdR in combination with DZNep exhibits a synergistic antineoplastic action against human HL-60 AML cells and the synergistic activation of several tumor suppressor genes. In this report, we showed that this combination also induced a synergistic activation of apoptosis in HL-60 cells. The synergistic antineoplastic action of 5-AZA-CdR plus DZNep was also observed on a second human myeloid leukemia cell line, AML-3. In addition, 5-AZA-CdR in combination with the specific inhibitors of EZH2, GSK-126, or GSK-343, also exhibited a synergistic antineoplastic action on both HL-60 and AML-3. The combined action of 5-AZA-CdR and DZNep on global gene expression in HL-60 cells was investigated in greater depth using RNA sequencing analysis. We observed that this combination of epigenetic agents exhibited a synergistic activation of hundreds of genes. The synergistic activation of so many genes that suppress malignancy by 5-AZA-CdR plus DZNep suggests that epigenetic gene silencing by DNA and histone methylation plays a major role in leukemogenesis. Targeting DNA and histone methylation is a promising approach that merits clinical investigation for the treatment of AML.
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Affiliation(s)
- Richard L Momparler
- Département de Pharmacologie, Université de Montréal, Montreal, QC, Canada; Centre de recherche, Service d'hématologie/oncologie, CHU-Saint-Justine, Montréal, QC, Canada
| | - Sylvie Côté
- Centre de recherche, Service d'hématologie/oncologie, CHU-Saint-Justine , Montréal, QC , Canada
| | - Louise F Momparler
- Centre de recherche, Service d'hématologie/oncologie, CHU-Saint-Justine , Montréal, QC , Canada
| | - Youssef Idaghdour
- Department of Biology, New York University Abu Dhabi , Abu Dhabi , United Arab Emirates
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Tahirov TH, Bushweller J. Structure and Biophysics of CBFβ/RUNX and Its Translocation Products. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 962:21-31. [PMID: 28299648 DOI: 10.1007/978-981-10-3233-2_2] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
The core binding factor (CBF) transcription factor is somewhat unique in that it is composed of a DNA binding RUNX subunit (RUNX1, 2, or 3) and a non-DNA binding CBFβ subunit, which modulates RUNX protein activity by modulating the auto-inhibition of the RUNX subunits. Since the discovery of this fascinating transcription factor more than 20 years ago, there has been a robust effort to characterize the structure as well as the biochemical properties of CBF. More recently, these efforts have also extended to the fusion proteins that arise from the subunits of CBF in leukemia. This chapter highlights the work of numerous labs which has provided a detailed understanding of the structure and function of this transcription factor and its fusion proteins.
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Affiliation(s)
- Tahir H Tahirov
- Eppley Institute for Research in Cancer and Allied Diseases, Fred & Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE, 68198, USA
| | - John Bushweller
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA, 22908, USA.
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Molecular Basis and Targeted Inhibition of CBFβ-SMMHC Acute Myeloid Leukemia. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 962:229-244. [PMID: 28299661 DOI: 10.1007/978-981-10-3233-2_15] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Acute myeloid leukemia (AML) is characterized by recurrent chromosomal rearrangements that encode for fusion proteins which drive leukemia initiation and maintenance. The inv(16) (p13q22) rearrangement is a founding mutation and the associated CBFβ-SMMHC fusion protein is essential for the survival of inv(16) AML cells. This Chapter will discuss our understanding of the function of this fusion protein in disrupting hematopoietic homeostasis and creating pre-leukemic blasts, in its cooperation with other co-occurring mutations during leukemia initiation, and in leukemia maintenance. In addition, this chapter will discuss the current approaches used for the treatment of inv(16) AML and the recent development of AI-10-49, a selective targeted inhibitor of CBFβ-SMMHC/RUNX1 binding, the first candidate targeted therapy for inv(16) AML.
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7
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De Braekeleer M, Douet-Guilbert N, De Braekeleer E. Prognostic impact ofp15gene aberrations in acute leukemia. Leuk Lymphoma 2016; 58:257-265. [DOI: 10.1080/10428194.2016.1201574] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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8
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Illendula A, Pulikkan JA, Zong H, Grembecka J, Xue L, Sen S, Zhou Y, Boulton A, Kuntimaddi A, Gao Y, Rajewski RA, Guzman ML, Castilla LH, Bushweller JH. Chemical biology. A small-molecule inhibitor of the aberrant transcription factor CBFβ-SMMHC delays leukemia in mice. Science 2015; 347:779-84. [PMID: 25678665 DOI: 10.1126/science.aaa0314] [Citation(s) in RCA: 95] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Acute myeloid leukemia (AML) is the most common form of adult leukemia. The transcription factor fusion CBFβ-SMMHC (core binding factor β and the smooth-muscle myosin heavy chain), expressed in AML with the chromosome inversion inv(16)(p13q22), outcompetes wild-type CBFβ for binding to the transcription factor RUNX1, deregulates RUNX1 activity in hematopoiesis, and induces AML. Current inv(16) AML treatment with nonselective cytotoxic chemotherapy results in a good initial response but limited long-term survival. Here, we report the development of a protein-protein interaction inhibitor, AI-10-49, that selectively binds to CBFβ-SMMHC and disrupts its binding to RUNX1. AI-10-49 restores RUNX1 transcriptional activity, displays favorable pharmacokinetics, and delays leukemia progression in mice. Treatment of primary inv(16) AML patient blasts with AI-10-49 triggers selective cell death. These data suggest that direct inhibition of the oncogenic CBFβ-SMMHC fusion protein may be an effective therapeutic approach for inv(16) AML, and they provide support for transcription factor targeted therapy in other cancers.
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Affiliation(s)
- Anuradha Illendula
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA 22908, USA
| | - John A Pulikkan
- Program in Gene Function and Expression, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Hongliang Zong
- Department of Medicine, Weill Medical College of Cornell University, New York, NY 10065, USA
| | - Jolanta Grembecka
- Department of Pathology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Liting Xue
- Program in Gene Function and Expression, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Siddhartha Sen
- Department of Medicine, Weill Medical College of Cornell University, New York, NY 10065, USA
| | - Yunpeng Zhou
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA 22908, USA
| | - Adam Boulton
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA 22908, USA
| | - Aravinda Kuntimaddi
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA 22908, USA
| | - Yan Gao
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA 22908, USA
| | - Roger A Rajewski
- Department of Pharmaceutical Chemistry, University of Kansas, Lawrence, KS 66045, USA
| | - Monica L Guzman
- Department of Medicine, Weill Medical College of Cornell University, New York, NY 10065, USA
| | - Lucio H Castilla
- Program in Gene Function and Expression, University of Massachusetts Medical School, Worcester, MA 01605, USA.
| | - John H Bushweller
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA 22908, USA.
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9
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Humeniuk R, Koller R, Bies J, Aplan P, Wolff L. Brief report: Loss of p15Ink4b accelerates development of myeloid neoplasms in Nup98-HoxD13 transgenic mice. Stem Cells 2014; 32:1361-6. [PMID: 24449168 DOI: 10.1002/stem.1635] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2013] [Accepted: 11/13/2013] [Indexed: 12/26/2022]
Abstract
Homeostasis of hematopoietic stem and progenitor cells is a tightly regulated process. The disturbance of the balance in the hematopoietic progenitor pool can result in favorable conditions for development of diseases such as myelodysplastic syndromes and leukemia. It has been shown recently that mice lacking p15Ink4b have skewed differentiation of common myeloid progenitors toward the myeloid lineage at the expense of erythroid progenitors. The lack of p15INK4B expression in human leukemic blasts has been linked to poor prognosis and increased risk of myelodysplastic syndromes transformation to acute myeloid leukemia. However, the role of p15Ink4b in disease development is just beginning to be elucidated. This study examines the collaboration of the loss of p15Ink4b with Nup98-HoxD13 translocation in the development of hematological malignancies in a mouse model. Here, we report that loss of p15Ink4b collaborates with Nup98-HoxD13 transgene in the development of predominantly myeloid neoplasms, namely acute myeloid leukemia, myeloproliferative disease, and myelodysplastic syndromes. This mouse model could be a very valuable tool for studying p15Ink4b function in tumorigenesis as well as preclinical drug testing.
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Affiliation(s)
- Rita Humeniuk
- National Cancer Institute, National Institutes of Health, Bethesda, Maryland, USA
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10
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Bodoor K, Haddad Y, Alkhateeb A, Al-Abbadi A, Dowairi M, Magableh A, Bsoul N, Ghabkari A. DNA hypermethylation of cell cycle (p15 and p16) and apoptotic (p14, p53, DAPK and TMS1) genes in peripheral blood of leukemia patients. Asian Pac J Cancer Prev 2014; 15:75-84. [PMID: 24528084 DOI: 10.7314/apjcp.2014.15.1.75] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Aberrant DNA methylation of tumor suppressor genes has been reported in all major types of leukemia with potential involvement in the inactivation of regulatory cell cycle and apoptosis genes. However, most of the previous reports did not show the extent of concurrent methylation of multiple genes in the four leukemia types. Here, we analyzed six key genes (p14, p15, p16, p53, DAPK and TMS1) for DNA methylation using methylation specific PCR to analyze peripheral blood of 78 leukemia patients (24 CML, 25 CLL, 12 AML, and 17 ALL) and 24 healthy volunteers. In CML, methylation was detected for p15 (11%), p16 (9%), p53 (23%) and DAPK (23%), in CLL, p14 (25%), p15 (19%), p16 (12%), p53 (17%) and DAPK (36%), in AML, p14 (8%), p15 (45%), p53 (9%) and DAPK (17%) and in ALL, p15 (14%), p16 (8%), and p53 (8%). This study highlighted an essential role of DAPK methylation in chronic leukemia in contrast to p15 methylation in the acute cases, whereas TMS1 hypermethylation was absent in all cases. Furthermore, hypermethylation of multiple genes per patient was observed, with obvious selectiveness in the 9p21 chromosomal region genes (p14, p15 and p16). Interestingly, methylation of p15 increased the risk of methylation in p53, and vice versa, by five folds (p=0.03) indicating possible synergistic epigenetic disruption of different phases of the cell cycle or between the cell cycle and apoptosis. The investigation of multiple relationships between methylated genes might shed light on tumor specific inactivation of the cell cycle and apoptotic pathways.
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Affiliation(s)
- Khaldon Bodoor
- Department of Biology, Jordan University of Science and Technology, Irbid, Jordan E-mail :
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11
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Wolff L, Bies J. p15Ink4b Functions in determining hematopoietic cell fates: implications for its role as a tumor suppressor. Blood Cells Mol Dis 2013; 50:227-31. [PMID: 23403260 DOI: 10.1016/j.bcmd.2013.01.006] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2012] [Accepted: 01/10/2013] [Indexed: 02/02/2023]
Abstract
The p15Ink4b gene is frequently hypermethylated in myeloid neoplasia and has been demonstrated to be a tumor suppressor. Since it is a member of the INK4b family of cyclin-dependent kinase inhibitors, it was initially presumed that its loss in leukemic blasts caused a dysregulation of the cell cycle. However, animal model experiments over the last several years have produced a very different picture of how p15Ink4b functions in hematopoietic cells and how its loss contributes to myelodysplastic syndrome and myeloid leukemia. It is clear now, that in early hematopoietic progenitors, p15Ink4b functions outside of its canonical role as a cell cycle inhibitor. Its functions are involved in signal transduction and influence the development of erythroid, monocytic and dendritic cells.
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Affiliation(s)
- Linda Wolff
- Laboratory of Cellular Oncology, National Cancer Institute, Room 4124, 37 Convent Dr. Bethesda, MD 20892, USA.
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12
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The role of tumor suppressor p15Ink4b in the regulation of hematopoietic progenitor cell fate. Blood Cancer J 2013; 3:e99. [PMID: 23359317 PMCID: PMC3556574 DOI: 10.1038/bcj.2012.44] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2012] [Revised: 10/31/2012] [Accepted: 11/26/2012] [Indexed: 01/20/2023] Open
Abstract
Epigenetic silencing of the tumor suppressor gene p15Ink4b (CDKN2B) is a frequent event in blood disorders like acute myeloid leukemia and myelodysplastic syndromes. The molecular function of p15Ink4b in hematopoietic differentiation still remains to be elucidated. Our previous study demonstrated that loss of p15Ink4b in mice results in skewing of the differentiation pattern of the common myeloid progenitor towards the myeloid lineage. Here, we investigated a function of p15Ink4b tumor suppressor gene in driving erythroid lineage commitment in hematopoietic progenitors. It was found that p15Ink4b is expressed more highly in committed megakaryocyte–erythroid progenitors than granulocyte–macrophage progenitors. More importantly, mice lacking p15Ink4b have lower numbers of primitive red cell progenitors and a severely impaired response to 5-fluorouracil- and phenylhydrazine-induced hematopoietic stress. Introduction of p15Ink4b into multipotential progenitors produced changes at the molecular level, including activation of mitogen-activated protein kinase\extracellular signal-regulated kinase (MEK/ERK) signaling, increase GATA-1, erythropoietin receptor (EpoR) and decrease Pu1, GATA-2 expression. These changes rendered cells more permissive to erythroid commitment and less permissive to myeloid commitment, as demonstrated by an increase in early burst-forming unit-erythroid formation with concomitant decrease in myeloid colonies. Our results indicate that p15Ink4b functions in hematopoiesis, by maintaining proper lineage commitment of progenitors and assisting in rapid red blood cells replenishment following stress.
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Goyama S, Mulloy JC. Molecular pathogenesis of core binding factor leukemia: current knowledge and future prospects. Int J Hematol 2011; 94:126-133. [PMID: 21537931 DOI: 10.1007/s12185-011-0858-z] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2011] [Revised: 03/24/2011] [Accepted: 04/06/2011] [Indexed: 12/24/2022]
Abstract
Core binding factor (CBF) acute myeloid leukemia (AML) is the most common cytogenetic subtype of AML, defined by the presence of t(8;21) or inv(16)/t(16;16). The chromosomal aberrations create AML1-ETO and CBFβ-MYH11 fusion genes that disrupt the functions of CBF, an essential transcription factor in hematopoiesis. Despite the relatively good outcome of patients with CBF-AML, only approximately half of the patients are cured with current therapy, indicating the need for improved therapeutic strategies. In this review, we summarize current knowledge regarding altered transcriptional regulation, aberrant signaling pathways, and cooperating genetic events in CBF leukemia, and discuss challenges ahead for translating these findings into the clinic.
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Affiliation(s)
- Susumu Goyama
- Division of Experimental Hematology and Cancer Biology, Cincinnati Children's Hospital Medical Center, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - James C Mulloy
- Division of Experimental Hematology and Cancer Biology, Cincinnati Children's Hospital Medical Center, University of Cincinnati College of Medicine, Cincinnati, OH, USA.
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14
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Oyer JA, Chu A, Brar S, Turker MS. Aberrant epigenetic silencing is triggered by a transient reduction in gene expression. PLoS One 2009; 4:e4832. [PMID: 19279688 PMCID: PMC2654015 DOI: 10.1371/journal.pone.0004832] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2009] [Accepted: 02/17/2009] [Indexed: 12/31/2022] Open
Abstract
Background Aberrant epigenetic silencing plays a major role in cancer formation by inactivating tumor suppressor genes. While the endpoints of aberrant silencing are known, i.e., promoter region DNA methylation and altered histone modifications, the triggers of silencing are not known. We used the tet-off system to test the hypothesis that a transient reduction in gene expression will sensitize a promoter to undergo epigenetic silencing. Methodology/Principal Findings The tet responsive promoter (PTRE) was used to drive expression of the selectable human HPRT cDNA in independent transfectants of an Hprt deficient mouse cell line. In this system, high basal HPRT expression is greatly reduced when doxycycline (Dox) is added to the culture medium. Exposure of the PTRE-HPRT transfectants to Dox induced HPRT deficient clones in a time dependent manner. A molecular analysis demonstrated promoter region DNA methylation, loss of histone modifications associated with expression (i.e., H3 lysine 9 and 14 acetylation and lysine 4 methylation), and acquisition of the repressive histone modification H3 lysine 9 methylation. These changes, which are consistent with aberrant epigenetic silencing, were not present in the Dox-treated cultures, with the exception of reduced H3 lysine 14 acetylation. Silenced alleles readily reactivated spontaneously or after treatment of cells with inhibitors of histone deacetylation and/or DNA methylation, but re-silencing of reactivated alleles did not require a new round of Dox exposure. Inhibition of histone deacetylation inhibited both the induction of silencing and re-silencing, whereas inhibition of DNA methylation had no such effect. Conclusions/Significance This study demonstrates that a transient reduction in gene expression triggers a pathway for aberrant silencing in mammalian cells and identifies histone deacetylation as a critical early step in this process. DNA methylation, in contrast, is a secondary step in the silencing pathway under study. A model to explain these observations is offered.
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Affiliation(s)
- Jon A. Oyer
- Department of Molecular and Medical Genetics, Oregon Health & Science University, Portland, Oregon, United States of America
| | - Adrian Chu
- Center for Research on Occupational and Environmental Toxicology (CROET), Oregon Health & Science University, Portland, Oregon, United States of America,
| | - Sukhmani Brar
- Center for Research on Occupational and Environmental Toxicology (CROET), Oregon Health & Science University, Portland, Oregon, United States of America,
| | - Mitchell S. Turker
- Department of Molecular and Medical Genetics, Oregon Health & Science University, Portland, Oregon, United States of America
- Center for Research on Occupational and Environmental Toxicology (CROET), Oregon Health & Science University, Portland, Oregon, United States of America,
- * E-mail:
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15
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Transcriptional repression of the RUNX3/AML2 gene by the t(8;21) and inv(16) fusion proteins in acute myeloid leukemia. Blood 2008; 112:3391-402. [PMID: 18663147 DOI: 10.1182/blood-2008-02-137083] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
RUNX3/AML2 is a Runt domain transcription factor like RUNX1/AML1 and RUNX2/AML3. Regulated by 2 promoters P1 and P2, RUNX3 is frequently inactivated by P2 methylation in solid tumors. Growing evidence has suggested a role of this transcription factor in hematopoiesis. However, genetic alterations have not been reported in blood cancers. In this study on 73 acute myeloid leukemia (AML) patients (44 children and 29 adults), we first showed that high RUNX3 expression among childhood AML was associated with a shortened event-free survival, and RUNX3 was significantly underexpressed in the prognostically favorable subgroup of AML with the t(8;21) and inv(16) translocations. We further demonstrated that this RUNX3 repression was mediated not by P2 methylation, but RUNX1-ETO and CBFbeta-MYH11, the fusion products of t(8;21) and inv(16), via a novel transcriptional mechanism that acts directly or indirectly in collaboration with RUNX1, on 2 conserved RUNX binding sites in the P1 promoter. In in vitro studies, ectopically expressed RUNX1-ETO and CBFbeta-MYH11 also inhibited endogenous RUNX3 expression. Taken together, RUNX3 was the first transcriptional target found to be commonly repressed by the t(8;21) and inv(16) fusion proteins and might have an important role in core-binding factor AML.
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Rosu-Myles M, Wolff L. p15Ink4b: Dual function in myelopoiesis and inactivation in myeloid disease. Blood Cells Mol Dis 2008; 40:406-9. [DOI: 10.1016/j.bcmd.2007.09.005] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2007] [Accepted: 09/13/2007] [Indexed: 11/25/2022]
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Lima PSP, Molffeta GA, Araujo AGD, Zago MA, Silva Jr. WAD. DNA methylation analysis of the tumor suppressor gene CDKN2B in Brazilian leukemia patients. Genet Mol Biol 2008. [DOI: 10.1590/s1415-47572008000400005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
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