Mus musculus
Ontology highlight
ABSTRACT:
PROVIDER: PRJNA319667 | ENA |
REPOSITORIES: ENA
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Project description:In human leukemia, lineage-specific genes represent predominant targets of deletion, with lymphoid-specific genes frequently affected in lymphoid leukemia and myeloid-specific genes in myeloid leukemia. To investigate the basis of lineage-specific alterations, we analyzed global DNA damage in primary B-cell precursors expressing leukemia-inducing oncogenes by ChIP-Seq. We identified >1000 sensitive regions, of which B-lineage-specific genes constitute the most prominent targets. Identified hotspots at B-lineage genes relate to DNA-DSBs, affect genes that harbor genomic lesions in human leukemia, and associate with ectopic deletion in successfully transformed cells. We further show that most identified regions overlap with gene bodies of highly expressed genes, and that induction of a myeloid lineage phenotype in transformed B-cell precursors promotes de novo DNA damage at myeloid loci. Hence, we demonstrate that lineage-specific transcription predisposes lineage-specific genes in transformed B-cell precursors to DNA damage, which is likely to promote the frequent alteration of lineage-specific genes in human leukemia.
2017-02-13 | GSE80682 | GEO
Project description:Oncogene driven transformation of leukemic progenitors results in B-acute lymphoblastic leukemia. Genetic deletions at specific hotspots are driven by recombination of epigenetically repressed loci and cause B cell transformation, and epigenetically regulated transcriptional plasticity has been proposed as a mechanism of differentiation arrest and resistance to therapy. The upstream signals driving epigenetic silencing have not been elucidated. BCR-ABL leukemias are initiated by leukemic stem cells/progenitors, and their modeling in vivo represents an opportunity for the identification of the epigenetic progress contributing to lineage leukemogenesis. We have found that primary human and murine BCR-ABL+ leukemic progenitors have increased activation of Cdc42 and the downstream atypical protein kinase C (aPKC). While the isoform aPKCz behaves as a leukemic suppressor, aPKCl/i is critically required for oncogenic progenitor proliferation, survival, and B cell differentiation arrest, but not for normal B cell lineage differentiation. We found that in vitro and in vivo B cell transformation by BCR-ABL requires the downregulation of key genes in the B-cell differentiation program through an aPKCl/i-dependent Etv5/Satb2 chromatin repressive signaling complex. Thus genetic or pharmacological targeting of aPKC impairs human oncogenic addicted leukemias in vitro and in vivo. Therefore, the aPKCl/i-SATB2 signaling cascade is required for leukemic BCR-ABL+ B-cell progenitor transformation and is amenable to non-BCR-ABL kinase inhibition.
2018-10-10 | GSE121018 | GEO
Project description:ZNF384-rearranged fusion oncoproteins (FO) define a subset of lineage ambiguous leukemias, but the mechanistic role of ZNF384 FO in leukemogenesis and lineage ambiguity is poorly understood. Here, using viral expression in mouse and human hematopoietic stem and progenitor cells (HSPCs) and a Ep300-Zfp384 mouse model we show that ZNF384 FO promote hematopoietic expansion, myeloid lineage skewing, and self-renewal. In mouse HSPCs, concomitant lesions such as NRASG12D, were required for fully penetrant leukemia, whereas expression of ZNF384 FO drove development of B/myeloid leukemia in human HSPCs, with sensitivity of human ZNF384r leukemia to FLT3 inhibition in vivo. Mechanistically, ZNF384 FO occupy a subset of predominantly intragenic/enhancer regions with increased histone 3 lysine acetylation suggesting enhancer function. These data define a paradigm for FO-driven lineage ambiguous leukemia, in which expression in HSPCs results in deregulation of lineage-specific genes and hematopoietic skewing, progressing to full leukemic transformation in the presence of proliferative stress.
2022-03-16 | PXD028481 | Pride
Project description:Noncoding mutation hotspots have been identified in melanoma and many of them occur at the binding sites of E26 transformation-specific (ETS) proteins; however, their formation mechanism and functional impacts are not fully understood. Here, we used UV damage sequencing data and analyzed cyclobutane pyrimidine dimer (CPD) formation, DNA repair, and CPD deamination in human cells at single-nucleotide resolution. Our data shows prominent CPD hotspots immediately after UV irradiation at ETS binding sites, particularly at sites with a conserved TTCCGG motif, which correlate with mutation hotspots identified in cutaneous melanoma. Additionally, CPDs are repaired slower at ETS binding sites than in flanking DNA. Cytosine deamination in CPDs to uracil is suggested as an important step for UV mutagenesis. However, we found that CPD deamination is significantly suppressed at ETS binding sites, particularly for the CPD hotspot on the 5’ side of the ETS motif, arguing against a role for CPD deamination in promoting ETS-associated UV mutations. Finally, we analyzed a subset of frequently mutated promoters, including the ribosomal protein genes RPL13A and RPS20, and found that mutations in the ETS motif can significantly reduce the promoter activity. Thus, our data identifies high UV damage and low repair, but not CPD deamination, as the main mechanism for ETS-associated mutations in melanoma and uncover new roles of often-overlooked mutation hotspots in perturbing gene transcription.
2023-12-01 | GSE235483 | GEO
Project description:HOXA9 Reprograms the Enhancer Landscape During Leukemic Transformation
| PRJNA401435 | ENA
Project description:Acute Myeloid Leukemia (AML) which occurs after an antecedent myeloproliferative neoplasm (MPN) has a dismal clinical prognosis and is not curative outside of the rare subset of patients who undergo successful allogeneic stem cell transplantation. As such, there is a pressing need for new mechanistic insights into how MPNs transform into AML and to use these insights to credential novel therapeutic approaches. The most common somatic mutational event which occurs in transformation from MPN to AML is mutation in TP53. However, the impact of TP53 allelic state on the ability to potentiate leukemic transformation, as well as the pathways involved in this process, have largely remained unresolved. Here we report the development of genetically accurate models of Jak2/Tp53 mutant MPN which undergoes progressive leukemic transformation with chromosomal instability similar to that observed in the clinical context. These models result in a fulminant erythroleukemia phenotype. We identify that leukemic transformation requires homozygous inactivation of TP53, and does not occur with heterozygous loss of Tp53. We further identify that the megakaryocyte erythroid progenitor (MEP) population is expanded prior to and after leukemic transformation, is characterized by progressive genomic instability (compared to other stem/progenitor compartments), and is capable of propagating the disease in vivo. Thus, the leukemia-initiating population is contained in the MEP compartment. Using gene-expression profiling we demonstrate that the BMP2/SMAD pathway (which is involved in self-renewal and DNA damage repair) is aberrantly activated in the leukemic phase of the disease. Importantly, attenuation of Bmp2 results in decreased self-renewal of leukemic cells in vitro and increased survival of leukemic mice in vivo, thus credentialing a biologic role for this pathway in leukemic transformation. Finally, given the loss of Tp53 function and associated disruption of DNA repair pathways, we hypothesized and subsequently identified that leukemic transformation is characterized by increased DNA damage. Using a synthetic-lethality strategy of targeting remaining DNA-repair pathways, using small-molecule inhibitors, in order to provoke biologically intolerable DNA damage and mitotic catastrophe, we demonstrate that Jak2/Tp53 mutant is highly sensitive to combined inhibition of WEE1 and PARP. This combination results in prolonged survival of mice and attenuates the leukemic phenotype. Collectively, these observations yield new mechanistic insights into the process of leukemic transformation resulting from TP53 alterations, and offer new, clinically-translatable, therapeutic options.
2022-05-24 | GSE180851 | GEO
Project description:Acute Myeloid Leukemia (AML) which occurs after an antecedent myeloproliferative neoplasm (MPN) has a dismal clinical prognosis and is not curative outside of the rare subset of patients who undergo successful allogeneic stem cell transplantation. As such, there is a pressing need for new mechanistic insights into how MPNs transform into AML and to use these insights to credential novel therapeutic approaches. The most common somatic mutational event which occurs in transformation from MPN to AML is mutation in TP53. However, the impact of TP53 allelic state on the ability to potentiate leukemic transformation, as well as the pathways involved in this process, have largely remained unresolved. Here we report the development of genetically accurate models of Jak2/Tp53 mutant MPN which undergoes progressive leukemic transformation with chromosomal instability similar to that observed in the clinical context. These models result in a fulminant erythroleukemia phenotype. We identify that leukemic transformation requires homozygous inactivation of TP53, and does not occur with heterozygous loss of Tp53. We further identify that the megakaryocyte erythroid progenitor (MEP) population is expanded prior to and after leukemic transformation, is characterized by progressive genomic instability (compared to other stem/progenitor compartments), and is capable of propagating the disease in vivo. Thus, the leukemia-initiating population is contained in the MEP compartment. Using gene-expression profiling we demonstrate that the BMP2/SMAD pathway (which is involved in self-renewal and DNA damage repair) is aberrantly activated in the leukemic phase of the disease. Importantly, attenuation of Bmp2 results in decreased self-renewal of leukemic cells in vitro and increased survival of leukemic mice in vivo, thus credentialing a biologic role for this pathway in leukemic transformation. Finally, given the loss of Tp53 function and associated disruption of DNA repair pathways, we hypothesized and subsequently identified that leukemic transformation is characterized by increased DNA damage. Using a synthetic-lethality strategy of targeting remaining DNA-repair pathways, using small-molecule inhibitors, in order to provoke biologically intolerable DNA damage and mitotic catastrophe, we demonstrate that Jak2/Tp53 mutant is highly sensitive to combined inhibition of WEE1 and PARP. This combination results in prolonged survival of mice and attenuates the leukemic phenotype. Collectively, these observations yield new mechanistic insights into the process of leukemic transformation resulting from TP53 alterations, and offer new, clinically-translatable, therapeutic options.
2022-05-24 | GSE180772 | GEO
Project description:Super-enhancers (SEs) are cis-regulatory elements enriching lineage specific key transcription factors (TFs) to form hotspots. A paucity of identification and functional dissection promoted us to investigate SEs during myoblast differentiation. ChIP-seq analysis of histone marks leads to the uncovering of SEs which remodel progressively during the course of differentiation. Further analyses of TF ChIP-seq enable the definition of SE hotspots co-bound by the master TF, MyoD and other TFs, among which we perform in-depth dissection for MyoD/FoxO3 interaction in driving the hotspots formation and SE activation.
2017-11-01 | GSE99207 | GEO
Project description:Super-enhancers (SEs) are cis-regulatory elements enriching lineage specific key transcription factors (TFs) to form hotspots. A paucity of identification and functional dissection promoted us to investigate SEs during myoblast differentiation. ChIP-seq analysis of histone marks leads to the uncovering of SEs which remodel progressively during the course of differentiation. Further analyses of TF ChIP-seq enable the definition of SE hotspots co-bound by the master TF, MyoD and other TFs, among which we perform in-depth dissection for MyoD/FoxO3 interaction in driving the hotspots formation and SE activation.
2017-06-02 | GSE93916 | GEO
Project description:Single strand breaks (SSBs) represent one of the most common types of DNA damage yet not much is known about the genome landscapes of this type of DNA lesions in mammalian cells. Here, we found that SSBs are more likely to occur in certain positions of the human genome — SSB hotspots — in different cells of the same cell type and in different cell types. We hypothesize that the hotspots are likely to represent biologically relevant breaks. And, we found that the hotspots had a prominent tendency to be enriched in the immediate vicinity of transcriptional start sites (TSSs). We show that these hotspots are not likely to represent technical artifacts, or be caused by common mechanisms previously found to cause DNA cleavage at promoters, such as apoptotic DNA fragmentation or topoisomerase type II (TOP2) activity. Therefore, such TSS-associated hotspots could potentially be generated using a novel mechanism, that could involve preferential cleavage at cytosines, and their existence is consistent with recent studies suggesting a complex relationship between DNA damage and regulation of gene expression.
2022-08-18 | GSE190735 | GEO