Publications by authors named "Ruud Delwel"

120 Publications

Allele-specific expression of GATA2 due to epigenetic dysregulation in CEBPA double mutant AML.

Blood 2021 Apr 8. Epub 2021 Apr 8.

Erasmus University Medical Center, Rotterdam, Netherlands.

Transcriptional deregulation is a central event in the development of acute myeloid leukemia (AML). To identify potential disturbances in gene regulation, we conducted an unbiased screen of allele-specific expression (ASE) in 209 AML cases. The gene encoding GATA binding protein 2 (GATA2) displayed ASE more often than any other myeloid or cancer-related gene. GATA2 ASE was strongly associated with CEBPA double mutations (CEBPA DM), with 95% of cases presenting GATA2 ASE. In CEBPA DM AML with GATA2 mutations, the mutated allele was preferentially expressed. We found that GATA2 ASE is a somatic event lost in complete remission, supporting the notion that it plays a role in CEBPA DM AML. Acquisition of GATA2 ASE involved silencing of one allele via promoter methylation and concurrent overactivation of the other allele, thereby preserving expression levels. Notably, promoter methylation was also lost in remission together with GATA2 ASE. In summary, we propose that GATA2 ASE is acquired by epigenetic mechanisms and is a prerequisite for the development of AML with CEBPA DM. This finding constitutes a novel example of an epigenetic hit cooperating with a genetic hit in the pathogenesis of AML.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1182/blood.2020009244DOI Listing
April 2021

Derepression of retroelements in acute myeloid leukemia with 3q aberrations.

Haematologica 2021 Mar 25. Epub 2021 Mar 25.

Molecular Leukemogenesis Group, German Cancer Research Center, Heidelberg, Germany; Internal Medicine V, Heidelberg University Hospital, Heidelberg, Germany; Oncology Center Worms.

Not available.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3324/haematol.2020.277400DOI Listing
March 2021

Somatic Mutations Drive Specific, but Reversible, Epigenetic Heterogeneity States in AML.

Cancer Discov 2020 Dec 16;10(12):1934-1949. Epub 2020 Sep 16.

Division of Hematology/Oncology, Weill Cornell Medicine, New York, New York.

Epigenetic allele diversity is linked to inferior prognosis in acute myeloid leukemia (AML). However, the source of epiallele heterogeneity in AML is unknown. Herein we analyzed epiallele diversity in a genetically and clinically annotated AML cohort. Notably, AML driver mutations linked to transcription factors and favorable outcome are associated with epigenetic destabilization in a defined set of susceptible loci. In contrast, AML subtypes linked to inferior prognosis manifest greater abundance and highly stochastic epiallele patterning. We report an epiallele outcome classifier supporting the link between epigenetic diversity and treatment failure. Mouse models with or mutations show that epiallele diversity is especially strongly induced by mutations, precedes transformation to AML, and is enhanced by cooperation between somatic mutations. Furthermore, epiallele complexity was partially reversed by epigenetic therapies in AML driven by /, suggesting that epigenetic therapy might function in part by reducing population complexity and fitness of AMLs. SIGNIFICANCE: We show for the first time that epigenetic clonality is directly linked to specific mutations and that epigenetic allele diversity precedes and potentially contributes to malignant transformation. Furthermore, epigenetic clonality is reversible with epigenetic therapy agents..
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1158/2159-8290.CD-19-0897DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7710625PMC
December 2020

BCL6 maintains survival and self-renewal of primary human acute myeloid leukemia cells.

Blood 2021 Feb;137(6):812-825

Division of Hematology and Medical Oncology, Department of Medicine, and.

B-cell lymphoma 6 (BCL6) is a transcription repressor and proto-oncogene that plays a crucial role in the innate and adaptive immune system and lymphoid neoplasms. However, its role in myeloid malignancies remains unclear. Here, we explored the role of BCL6 in acute myeloid leukemia (AML). BCL6 was expressed at variable and often high levels in AML cell lines and primary AML samples. AMLs with higher levels of BCL6 were generally sensitive to treatment with BCL6 inhibitors, with the exception of those with monocytic differentiation. Gene expression profiling of AML cells treated with a BCL6 inhibitor revealed induction of BCL6-repressed target genes and transcriptional programs linked to DNA damage checkpoints and downregulation of stem cell genes. Ex vivo treatment of primary AML cells with BCL6 inhibitors induced apoptosis and decreased colony-forming capacity, which correlated with the levels of BCL6 expression. Importantly, inhibition or knockdown of BCL6 in primary AML cells resulted in a significant reduction of leukemia-initiating capacity in mice, suggesting ablation of leukemia repopulating cell functionality. In contrast, BCL6 knockout or inhibition did not suppress the function of normal hematopoietic stem cells. Treatment with cytarabine further induced BCL6 expression, and the levels of BCL6 induction were correlated with resistance to cytarabine. Treatment of AML patient-derived xenografts with BCL6 inhibitor plus cytarabine suggested enhanced antileukemia activity with this combination. Hence, pharmacologic inhibition of BCL6 might provide a novel therapeutic strategy for ablation of leukemia-repopulating cells and increased responsiveness to chemotherapy.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1182/blood.2019001745DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7885821PMC
February 2021

Atypical 3q26/MECOM rearrangements genocopy inv(3)/t(3;3) in acute myeloid leukemia.

Blood 2020 07;136(2):224-234

Department of Hematology.

Acute myeloid leukemia (AML) with inv(3)/t(3;3)(q21q26) is a distinct World Health Organization recognized entity, characterized by its aggressive course and poor prognosis. In this subtype of AML, the translocation of a GATA2 enhancer (3q21) to MECOM (3q26) results in overexpression of the MECOM isoform EVI1 and monoallelic expression of GATA2 from the unaffected allele. The full-length MECOM transcript, MDS1-EVI1, is not expressed as the result of the 3q26 rearrangement. Besides the classical inv(3)/t(3;3), a number of other 3q26/MECOM rearrangements with poor treatment response have been reported in AML. Here, we demonstrate, in a group of 33 AML patients with atypical 3q26 rearrangements, MECOM involvement with EVI1 overexpression but no or low MDS1-EVI1 levels. Moreover, the 3q26 translocations in these AML patients often involve superenhancers of genes active in myeloid development (eg, CD164, PROM1, CDK6, or MYC). In >50% of these cases, allele-specific GATA2 expression was observed, either by copy-number loss or by an unexplained allelic imbalance. Altogether, atypical 3q26 recapitulate the main leukemic mechanism of inv(3)/t(3;3) AML, namely EVI1 overexpression driven by enhancer hijacking, absent MDS1-EVI1 expression and potential GATA2 involvement. Therefore, we conclude that both atypical 3q26/MECOM and inv(3)/t(3;3) can be classified as a single entity of 3q26-rearranged AMLs. Routine analyses determining MECOM rearrangements and EVI1 and MDS1-EVI1 expression are required to recognize 3q-rearranged AML cases.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1182/blood.2019003701DOI Listing
July 2020

RUNX1-ETO Depletion in t(8;21) AML Leads to C/EBPα- and AP-1-Mediated Alterations in Enhancer-Promoter Interaction.

Cell Rep 2019 Sep;28(12):3022-3031.e7

Institute of Cancer and Genomic Sciences, University of Birmingham, Birmingham B152TT, UK. Electronic address:

Acute myeloid leukemia (AML) is associated with mutations in transcriptional and epigenetic regulator genes impairing myeloid differentiation. The t(8;21)(q22;q22) translocation generates the RUNX1-ETO fusion protein, which interferes with the hematopoietic master regulator RUNX1. We previously showed that the maintenance of t(8;21) AML is dependent on RUNX1-ETO expression. Its depletion causes extensive changes in transcription factor binding, as well as gene expression, and initiates myeloid differentiation. However, how these processes are connected within a gene regulatory network is unclear. To address this question, we performed Promoter-Capture Hi-C assays, with or without RUNX1-ETO depletion and assigned interacting cis-regulatory elements to their respective genes. To construct a RUNX1-ETO-dependent gene regulatory network maintaining AML, we integrated cis-regulatory element interactions with gene expression and transcription factor binding data. This analysis shows that RUNX1-ETO participates in cis-regulatory element interactions. However, differential interactions following RUNX1-ETO depletion are driven by alterations in the binding of RUNX1-ETO-regulated transcription factors.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.celrep.2019.08.040DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6899442PMC
September 2019

Therapeutic Targeting of RNA Splicing Catalysis through Inhibition of Protein Arginine Methylation.

Cancer Cell 2019 08;36(2):194-209.e9

Ontario Cancer Institute/Princess Margaret Hospital, Toronto, ON M5G 2M9, Canada.

Cancer-associated mutations in genes encoding RNA splicing factors (SFs) commonly occur in leukemias, as well as in a variety of solid tumors, and confer dependence on wild-type splicing. These observations have led to clinical efforts to directly inhibit the spliceosome in patients with refractory leukemias. Here, we identify that inhibiting symmetric or asymmetric dimethylation of arginine, mediated by PRMT5 and type I protein arginine methyltransferases (PRMTs), respectively, reduces splicing fidelity and results in preferential killing of SF-mutant leukemias over wild-type counterparts. These data identify genetic subsets of cancer most likely to respond to PRMT inhibition, synergistic effects of combined PRMT5 and type I PRMT inhibition, and a mechanistic basis for the therapeutic efficacy of PRMT inhibition in cancer.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.ccell.2019.07.003DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7194031PMC
August 2019

Subtype-specific regulatory network rewiring in acute myeloid leukemia.

Nat Genet 2019 01 12;51(1):151-162. Epub 2018 Nov 12.

Institute of Cancer and Genomic Sciences, University of Birmingham, Birmingham, UK.

Acute myeloid leukemia (AML) is a heterogeneous disease caused by a variety of alterations in transcription factors, epigenetic regulators and signaling molecules. To determine how different mutant regulators establish AML subtype-specific transcriptional networks, we performed a comprehensive global analysis of cis-regulatory element activity and interaction, transcription factor occupancy and gene expression patterns in purified leukemic blast cells. Here, we focused on specific subgroups of subjects carrying mutations in genes encoding transcription factors (RUNX1, CEBPα), signaling molecules (FTL3-ITD, RAS) and the nuclear protein NPM1). Integrated analysis of these data demonstrates that each mutant regulator establishes a specific transcriptional and signaling network unrelated to that seen in normal cells, sustaining the expression of unique sets of genes required for AML growth and maintenance.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41588-018-0270-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6330064PMC
January 2019

Temporal autoregulation during human PU.1 locus SubTAD formation.

Blood 2018 12 12;132(25):2643-2655. Epub 2018 Oct 12.

Institute of Molecular Tumor Biology and.

Epigenetic control of gene expression occurs within discrete spatial chromosomal units called topologically associating domains (TADs), but the exact spatial requirements of most genes are unknown; this is of particular interest for genes involved in cancer. We therefore applied high-resolution chromosomal conformation capture sequencing to map the three-dimensional (3D) organization of the human locus encoding the key myeloid transcription factor PU.1 in healthy monocytes and acute myeloid leukemia (AML) cells. We identified a dynamic ∼75-kb unit (SubTAD) as the genomic region in which spatial interactions between PU.1 gene regulatory elements occur during myeloid differentiation and are interrupted in AML. Within this SubTAD, proper initiation of the spatial chromosomal interactions requires PU.1 autoregulation and recruitment of the chromatin-adaptor protein LDB1 (LIM domain-binding protein 1). However, once these spatial interactions have occurred, LDB1 stabilizes them independently of PU.1 autoregulation. Thus, our data support that PU.1 autoregulates its expression in a "hit-and-run" manner by initiating stable chromosomal loops that result in a transcriptionally active chromatin architecture.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1182/blood-2018-02-834721DOI Listing
December 2018

Correction to: EVI2B is a C/EBPα target gene required for granulocytic differentiation and functionality of hematopoietic progenitors.

Cell Death Differ 2019 Jan;26(1):198

Department of Hemato-Oncology, Institute of Molecular Genetics of the ASCR, Videnska 1083, Prague 142 20, Prague 4, Czech Republic.

Since publication of this article, the authors identified an error in the acknowledgments section. The original sentence in acknowledgments reads as follows.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41418-018-0146-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6294764PMC
January 2019

Puzzling pieces of chromosome 7 loss or deletion.

Blood 2018 06;131(26):2871-2872

Erasmus MC Cancer Institute.

View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1182/blood-2018-04-844746DOI Listing
June 2018

The basic helix-loop-helix transcription factor SHARP1 is an oncogenic driver in MLL-AF6 acute myelogenous leukemia.

Nat Commun 2018 04 24;9(1):1622. Epub 2018 Apr 24.

Cancer Science Institute of Singapore, National University of Singapore, Singapore, 117599, Singapore.

Acute Myeloid Leukemia (AML) with MLL gene rearrangements demonstrate unique gene expression profiles driven by MLL-fusion proteins. Here, we identify the circadian clock transcription factor SHARP1 as a novel oncogenic target in MLL-AF6 AML, which has the worst prognosis among all subtypes of MLL-rearranged AMLs. SHARP1 is expressed solely in MLL-AF6 AML, and its expression is regulated directly by MLL-AF6/DOT1L. Suppression of SHARP1 induces robust apoptosis of human MLL-AF6 AML cells. Genetic deletion in mice delays the development of leukemia and attenuated leukemia-initiating potential, while sparing normal hematopoiesis. Mechanistically, SHARP1 binds to transcriptionally active chromatin across the genome and activates genes critical for cell survival as well as key oncogenic targets of MLL-AF6. Our findings demonstrate the unique oncogenic role for SHARP1 in MLL-AF6 AML.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41467-018-03854-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5915391PMC
April 2018

RUNX1-ETO and RUNX1-EVI1 Differentially Reprogram the Chromatin Landscape in t(8;21) and t(3;21) AML.

Cell Rep 2017 05;19(8):1654-1668

Institute for Cancer and Genomic Sciences, College of Medicine and Dentistry, University of Birmingham, B15 2TT Birmingham, UK. Electronic address:

Acute myeloid leukemia (AML) is a heterogeneous disease caused by mutations in transcriptional regulator genes, but how different mutant regulators shape the chromatin landscape is unclear. Here, we compared the transcriptional networks of two types of AML with chromosomal translocations of the RUNX1 locus that fuse the RUNX1 DNA-binding domain to different regulators, the t(8;21) expressing RUNX1-ETO and the t(3;21) expressing RUNX1-EVI1. Despite containing the same DNA-binding domain, the two fusion proteins display distinct binding patterns, show differences in gene expression and chromatin landscape, and are dependent on different transcription factors. RUNX1-EVI1 directs a stem cell-like transcriptional network reliant on GATA2, whereas that of RUNX1-ETO-expressing cells is more mature and depends on RUNX1. However, both types of AML are dependent on the continuous expression of the fusion proteins. Our data provide a molecular explanation for the differences in clinical prognosis for these types of AML.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.celrep.2017.05.005DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5457485PMC
May 2017

Epigenetic Identity in AML Depends on Disruption of Nonpromoter Regulatory Elements and Is Affected by Antagonistic Effects of Mutations in Epigenetic Modifiers.

Cancer Discov 2017 08 13;7(8):868-883. Epub 2017 Apr 13.

Department of Human Genetics and Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, Miami, Florida.

We performed cytosine methylation sequencing on genetically diverse patients with acute myeloid leukemia (AML) and found leukemic DNA methylation patterning is primarily driven by nonpromoter regulatory elements and CpG shores. Enhancers displayed stronger differential methylation than promoters, consisting predominantly of hypomethylation. AMLs with dominant hypermethylation featured greater epigenetic disruption of promoters, whereas those with dominant hypomethylation displayed greater disruption of distal and intronic regions. Mutations in and had opposing and mutually exclusive effects on the epigenome. Notably, co-occurrence of both mutations resulted in epigenetic antagonism, with most CpGs affected by either mutation alone no longer affected in double-mutant AMLs. Importantly, this epigenetic antagonism precedes malignant transformation and can be observed in preleukemic LSK cells from or single-mutant and / double-mutant mice. Notably, double-mutant AMLs manifested upregulation of a RAS signaling signature and displayed unique sensitivity to MEK inhibition as compared with AMLs with either single mutation. AML is biologically heterogeneous with subtypes characterized by specific genetic and epigenetic abnormalities. Comprehensive DNA methylation profiling revealed that differential methylation of nonpromoter regulatory elements is a driver of epigenetic identity, that gene mutations can be context-dependent, and that co-occurrence of mutations in epigenetic modifiers can result in epigenetic antagonism. .
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1158/2159-8290.CD-16-1032DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5540802PMC
August 2017

EVI2B is a C/EBPα target gene required for granulocytic differentiation and functionality of hematopoietic progenitors.

Cell Death Differ 2017 04 10;24(4):705-716. Epub 2017 Feb 10.

Department of Hemato-oncology, Institute of Molecular Genetics of the ASCR, Videnska 1083, Prague 142 20 Prague 4, Czech Republic.

Development of hematopoietic populations through the process of differentiation is critical for proper hematopoiesis. The transcription factor CCAAT/enhancer binding protein alpha (C/EBPα) is a master regulator of myeloid differentiation, and the identification of C/EBPα target genes is key to understand this process. Here we identified the Ecotropic Viral Integration Site 2B (EVI2B) gene as a direct target of C/EBPα. We showed that the product of the gene, the transmembrane glycoprotein EVI2B (CD361), is abundantly expressed on the surface of primary hematopoietic cells, the highest levels of expression being reached in mature granulocytes. Using shRNA-mediated downregulation of EVI2B in human and murine cell lines and in primary hematopoietic stem and progenitor cells, we demonstrated impaired myeloid lineage development and altered progenitor functions in EVI2B-silenced cells. We showed that the compromised progenitor functionality in Evi2b-depleted cells can be in part explained by deregulation of cell proliferation and apoptosis. In addition, we generated an Evi2b knockout murine model and demonstrated altered properties of hematopoietic progenitors, as well as impaired G-CSF dependent myeloid colony formation in the knockout cells. Remarkably, we found that EVI2B is significantly downregulated in human acute myeloid leukemia samples characterized by defects in CEBPA. Altogether, our data demonstrate that EVI2B is a downstream target of C/EBPα, which regulates myeloid differentiation and functionality of hematopoietic progenitors.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/cdd.2017.6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5384033PMC
April 2017

Expression and regulation of C/EBPα in normal myelopoiesis and in malignant transformation.

Blood 2017 04 8;129(15):2083-2091. Epub 2017 Feb 8.

Department of Hematology, Erasmus University Medical Center, Rotterdam, The Netherlands.

One of the most studied transcription factors in hematopoiesis is the leucine zipper CCAAT-enhancer binding protein α (C/EBPα), which is mainly involved in cell fate decisions for myeloid differentiation. Its involvement in acute myeloid leukemia (AML) is diverse, with patients frequently exhibiting mutations, deregulation of gene expression, or alterations in the function of C/EBPα. In this review, we emphasize the importance of C/EBPα for neutrophil maturation, its role in myeloid priming of hematopoietic stem and progenitor cells, and its indispensable requirement for AML development. We discuss that mutations in the open reading frame of lead to an altered C/EBPα function, affecting the expression of downstream genes and consequently deregulating myelopoiesis. The emerging transcriptional mechanisms of are discussed based on recent studies. Novel insights on how these mechanisms may be deregulated by oncoproteins or mutations/variants in enhancers are suggested in principal to reveal novel mechanisms of how is deregulated at the transcriptional level.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1182/blood-2016-09-687822DOI Listing
April 2017

Myeloid leukemia with transdifferentiation plasticity developing from T-cell progenitors.

EMBO J 2016 11 29;35(22):2399-2416. Epub 2016 Aug 29.

Institute of Molecular Tumor Biology, University of Münster, Münster, Germany

Unfavorable patient survival coincides with lineage plasticity observed in human acute leukemias. These cases are assumed to arise from hematopoietic stem cells, which have stable multipotent differentiation potential. However, here we report that plasticity in leukemia can result from instable lineage identity states inherited from differentiating progenitor cells. Using mice with enhanced c-Myc expression, we show, at the single-cell level, that T-lymphoid progenitors retain broad malignant lineage potential with a high capacity to differentiate into myeloid leukemia. These T-cell-derived myeloid blasts retain expression of a defined set of T-cell transcription factors, creating a lymphoid epigenetic memory that confers growth and propagates myeloid/T-lymphoid plasticity. Based on these characteristics, we identified a correlating human leukemia cohort and revealed targeting of Jak2/Stat3 signaling as a therapeutic possibility. Collectively, our study suggests the thymus as a source for myeloid leukemia and proposes leukemic plasticity as a driving mechanism. Moreover, our results reveal a pathway-directed therapy option against thymus-derived myeloid leukemogenesis and propose a model in which dynamic progenitor differentiation states shape unique neoplastic identities and therapy responses.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.15252/embj.201693927DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5109237PMC
November 2016

Distinct evolution and dynamics of epigenetic and genetic heterogeneity in acute myeloid leukemia.

Nat Med 2016 07 20;22(7):792-9. Epub 2016 Jun 20.

Department of Biostatistics and Computational Biology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA.

Genetic heterogeneity contributes to clinical outcome and progression of most tumors, but little is known about allelic diversity for epigenetic compartments, and almost no data exist for acute myeloid leukemia (AML). We examined epigenetic heterogeneity as assessed by cytosine methylation within defined genomic loci with four CpGs (epialleles), somatic mutations, and transcriptomes of AML patient samples at serial time points. We observed that epigenetic allele burden is linked to inferior outcome and varies considerably during disease progression. Epigenetic and genetic allelic burden and patterning followed different patterns and kinetics during disease progression. We observed a subset of AMLs with high epiallele and low somatic mutation burden at diagnosis, a subset with high somatic mutation and lower epiallele burdens at diagnosis, and a subset with a mixed profile, suggesting distinct modes of tumor heterogeneity. Genes linked to promoter-associated epiallele shifts during tumor progression showed increased single-cell transcriptional variance and differential expression, suggesting functional impact on gene regulation. Thus, genetic and epigenetic heterogeneity can occur with distinct kinetics likely to affect the biological and clinical features of tumors.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/nm.4125DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4938719PMC
July 2016

MEIS1-mediated transactivation of synaptotagmin-like 1 promotes CXCL12/CXCR4 signaling and leukemogenesis.

J Clin Invest 2016 05 28;126(5):1664-78. Epub 2016 Mar 28.

The TALE-class homeoprotein MEIS1 specifically collaborates with HOXA9 to drive myeloid leukemogenesis. Although MEIS1 alone has only a moderate effect on cell proliferation in vitro, it is essential for the development of HOXA9-induced leukemia in vivo. Here, using murine models of leukemogenesis, we have shown that MEIS1 promotes leukemic cell homing and engraftment in bone marrow and enhances cell-cell interactions and cytokine-mediated cell migration. We analyzed global DNA binding of MEIS1 in leukemic cells as well as gene expression alterations in MEIS1-deficent cells and identified synaptotagmin-like 1 (Sytl1, also known as Slp1) as the MEIS1 target gene that cooperates with Hoxa9 in leukemogenesis. Replacement of SYTL1 in MEIS1-deficent cells restored both cell migration and engraftment. Further analysis revealed that SYTL1 promotes cell migration via activation of the CXCL12/CXCR4 axis, as SYTL1 determines intracellular trafficking of CXCR4. Together, our results reveal that MEIS1, through induction of SYTL1, promotes leukemogenesis and supports leukemic cell homing and engraftment, facilitating interactions between leukemic cells and bone marrow stroma.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1172/JCI81516DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4855920PMC
May 2016

DNMT3A Haploinsufficiency Transforms FLT3ITD Myeloproliferative Disease into a Rapid, Spontaneous, and Fully Penetrant Acute Myeloid Leukemia.

Cancer Discov 2016 05 25;6(5):501-15. Epub 2016 Mar 25.

Division of Immunobiology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio. Division of Experimental Hematology and Cancer Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio.

Unlabelled: Cytogenetically normal acute myeloid leukemia (CN-AML) represents nearly 50% of human AML. Co-occurring mutations in the de novo DNA methyltransferase DNMT3A and the FMS related tyrosine kinase 3 (FLT3) are common in CN-AML and confer a poorer prognosis. We demonstrate that mice with Flt3-internal tandem duplication (Flt3(ITD)) and inducible deletion of Dnmt3a spontaneously develop a rapidly lethal, completely penetrant, and transplantable AML of normal karyotype. AML cells retain a single Dnmt3a floxed allele, revealing the oncogenic potential of Dnmt3a haploinsufficiency. FLT3(ITD)/DNMT3A-mutant primary human and murine AML exhibit a similar pattern of global DNA methylation associated with changes in the expression of nearby genes. In the murine model, rescuing Dnmt3a expression was accompanied by DNA remethylation and loss of clonogenic potential, suggesting that Dnmt3a-mutant oncogenic effects are reversible. Dissection of the cellular architecture of the AML model using single-cell assays, including single-cell RNA sequencing, identified clonogenic subpopulations that express genes sensitive to the methylation of nearby genomic loci and responsive to DNMT3A levels. Thus, Dnmt3a haploinsufficiency transforms Flt3(ITD) myeloproliferative disease by modulating methylation-sensitive gene expression within a clonogenic AML subpopulation.

Significance: DNMT3A haploinsufficiency results in reversible epigenetic alterations that transform FLT3(ITD)-mutant myeloproliferative neoplasm into AML. Cancer Discov; 6(5); 501-15. ©2016 AACR.This article is highlighted in the In This Issue feature, p. 461.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1158/2159-8290.CD-16-0008DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4861898PMC
May 2016

An autonomous CEBPA enhancer specific for myeloid-lineage priming and neutrophilic differentiation.

Blood 2016 06 10;127(24):2991-3003. Epub 2016 Mar 10.

Department of Hematology.

Neutrophilic differentiation is dependent on CCAAT enhancer-binding protein α (C/EBPα), a transcription factor expressed in multiple organs including the bone marrow. Using functional genomic technologies in combination with clustered regularly-interspaced short palindromic repeat (CRISPR)/CRISPR-associated protein 9 genome editing and in vivo mouse modeling, we show that CEBPA is located in a 170-kb topological-associated domain that contains 14 potential enhancers. Of these, 1 enhancer located +42 kb from CEBPA is active and engages with the CEBPA promoter in myeloid cells only. Germ line deletion of the homologous enhancer in mice in vivo reduces Cebpa levels exclusively in hematopoietic stem cells (HSCs) and myeloid-primed progenitor cells leading to severe defects in the granulocytic lineage, without affecting any other Cebpa-expressing organ studied. The enhancer-deleted progenitor cells lose their myeloid transcription program and are blocked in differentiation. Deletion of the enhancer also causes loss of HSC maintenance. We conclude that a single +42-kb enhancer is essential for CEBPA expression in myeloid cells only.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1182/blood-2016-01-695759DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5043424PMC
June 2016

A somatic mutation of GFI1B identified in leukemia alters cell fate via a SPI1 (PU.1) centered genetic regulatory network.

Dev Biol 2016 Mar 3;411(2):277-286. Epub 2016 Feb 3.

UCL Cancer Institute, Paul O'Gorman Building 72 Huntley St., London WC1E6BT, United Kingdom. Electronic address:

We identify a mutation (D262N) in the erythroid-affiliated transcriptional repressor GFI1B, in an acute myeloid leukemia (AML) patient with antecedent myelodysplastic syndrome (MDS). The GFI1B-D262N mutant functionally antagonizes the transcriptional activity of wild-type GFI1B. GFI1B-D262N promoted myelomonocytic versus erythroid output from primary human hematopoietic precursors and enhanced cell survival of both normal and MDS derived precursors. Re-analysis of AML transcriptome data identifies a distinct group of patients in whom expression of wild-type GFI1B and SPI1 (PU.1) have an inverse pattern. In delineating this GFI1B-SPI1 relationship we show that (i) SPI1 is a direct target of GFI1B, (ii) expression of GFI1B-D262N produces elevated expression of SPI1, and (iii) SPI1-knockdown restores balanced lineage output from GFI1B-D262N-expressing precursors. These results table the SPI1-GFI1B transcriptional network as an important regulatory axis in AML as well as in the development of erythroid versus myelomonocytic cell fate.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.ydbio.2016.02.002DOI Listing
March 2016

Epigenetics and approaches to targeted epigenetic therapy in acute myeloid leukemia.

Blood 2016 Jan 10;127(1):42-52. Epub 2015 Dec 10.

Department of Hematology, Erasmus Medical Center, Rotterdam, The Netherlands.

Acute myeloid leukemia (AML) is the most common type of acute leukemia in adults. AML is a heterogeneous malignancy characterized by distinct genetic abnormalities. Recent discoveries have highlighted an additional important role of dysregulated epigenetic mechanisms in the pathogenesis of the disease. In contrast to genetic changes, epigenetic modifications are frequently reversible, which provides opportunities for targeted treatment using specific inhibitors. In this review, we will provide an overview of the current state of epigenetics and epigenetic therapy in AML and will describe perspectives on how to identify promising new approaches for epigenetic targeted treatment.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1182/blood-2015-07-604512DOI Listing
January 2016

Congenital thrombocytopenia in a neonate with an interstitial microdeletion of 3q26.2q26.31.

Am J Med Genet A 2016 Feb 10;170A(2):504-509. Epub 2015 Nov 10.

Department of Paediatrics, Academic Medical Center, Amsterdam, The Netherlands.

Interstitial deletions encompassing the 3q26.2 region are rare. Only one case-report was published this far describing a patient with an interstitial deletion of 3q26.2 (involving the MDS1-EVI1 complex (MECOM)) and congenital thrombocytopenia. In this report we describe a case of a neonate with congenital thrombocytopenia and a constitutional 4.52 Mb deletion of 3q26.2q26.31 including TERC and the first 2 exons of MECOM, involving MDS1 but not EVI1. The deletion was demonstrated by array-CGH on lymphocytes. Our report confirms that congenital thrombocytopenia can be due to a constitutional deletion of 3q26.2 involving MECOM. We suggest that in case of unexplained neonatal thrombocytopenia, with even just slight facial dysmorphism, DNA microarray on peripheral blood should be considered early in the diagnostic work-up.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/ajmg.a.37451DOI Listing
February 2016

Pharmacological targeting of the Wdr5-MLL interaction in C/EBPα N-terminal leukemia.

Nat Chem Biol 2015 Aug 13;11(8):571-578. Epub 2015 Jul 13.

Structural Genomics Consortium, University of Toronto, Toronto, ON, M5G 1L7, Canada.

The CEBPA gene is mutated in 9% of patients with acute myeloid leukemia (AML). Selective expression of a short (30-kDa) CCAAT-enhancer binding protein-α (C/EBPα) translational isoform, termed p30, represents the most common type of CEBPA mutation in AML. The molecular mechanisms underlying p30-mediated transformation remain incompletely understood. We show that C/EBPα p30, but not the normal p42 isoform, preferentially interacts with Wdr5, a key component of SET/MLL (SET-domain/mixed-lineage leukemia) histone-methyltransferase complexes. Accordingly, p30-bound genomic regions were enriched for MLL-dependent H3K4me3 marks. The p30-dependent increase in self-renewal and inhibition of myeloid differentiation required Wdr5, as downregulation of the latter inhibited proliferation and restored differentiation in p30-dependent AML models. OICR-9429 is a new small-molecule antagonist of the Wdr5-MLL interaction. This compound selectively inhibited proliferation and induced differentiation in p30-expressing human AML cells. Our data reveal the mechanism of p30-dependent transformation and establish the essential p30 cofactor Wdr5 as a therapeutic target in CEBPA-mutant AML.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/nchembio.1859DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4511833PMC
August 2015

Downregulation of the Wnt inhibitor CXXC5 predicts a better prognosis in acute myeloid leukemia.

Blood 2015 May 24;125(19):2985-94. Epub 2015 Mar 24.

Department of Medical and Molecular Genetics, King's College London, Faculty of Life Sciences and Medicine, London, United Kingdom;

The gene CXXC5 on 5q31 is frequently deleted in acute myeloid leukemia (AML) with del(5q), suggesting that inactivation of CXXC5 might play a role in leukemogenesis. Here, we investigated the functional and prognostic implications of CXXC5 expression in AML. CXXC5 mRNA was downregulated in AML with MLL rearrangements, t(8;21) and GATA2 mutations. As a mechanism of CXXC5 inactivation, we found evidence for epigenetic silencing by promoter methylation. Patients with CXXC5 expression below the median level had a lower relapse rate (45% vs 59%; P = .007) and a better overall survival (OS, 46% vs 28%; P < .001) and event-free survival (EFS, 36% vs 21%; P < .001) at 5 years, independent of cytogenetic risk groups and known molecular risk factors. In gene-expression profiling, lower CXXC5 expression was associated with upregulation of cell-cycling genes and co-downregulation of genes implicated in leukemogenesis (WT1, GATA2, MLL, DNMT3B, RUNX1). Functional analyses demonstrated CXXC5 to inhibit leukemic cell proliferation and Wnt signaling and to affect the p53-dependent DNA damage response. In conclusion, our data suggest a tumor suppressor function of CXXC5 in AML. Inactivation of CXXC5 is associated with different leukemic pathways and defines an AML subgroup with better outcome.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1182/blood-2014-12-613703DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4463809PMC
May 2015