Whole cell proteome of U-2 OS cells with NPM1 and NPM1c overexpression
Ontology highlight
ABSTRACT:
INSTRUMENT(S): Orbitrap Fusion Lumos
ORGANISM(S): Homo Sapiens (human)
TISSUE(S): Cell Culture
SUBMITTER: 
Stefan Müller
LAB HEAD: Srefan Müller
PROVIDER: PXD040193 | Pride | 2023-11-20
REPOSITORIES: Pride
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Project description:NPM1 is the most frequently mutated gene in cytogenetically normal acute myeloid leukemia (AML). In AML cells, NPM1 mutations result in abnormal cytoplasmic localization of the mutant protein (NPM1c). NPM1 mutations are founding genetic lesions, however it is unknown whether NPM1c is required to maintain the leukemic state. Here, we show that loss of NPM1c from the cytoplasm, either through nuclear relocalization or targeted degradation, results in downregulation of homeobox (HOX) genes, and differentiation and cell growth arrest of AML cells. Additionally, we show that HOX downregulation is the earliest transcriptional event following the loss of NPM1c from the cytoplasm, preceding and promoting differentiation. Finally, we show that XPO1 inhibition efficiently relocalizes NPM1c to the nucleus, enables differentiation and prolongs survival of Npm1c+ leukemic mice. We describe an exquisite dependency of NPM1-mutant AML cells on NPM1c, providing the rationale for the use of nuclear export inhibitors in AML with mutated NPM1.
2018-08-06 | GSE111179 | GEO
Project description:NPM1 is the most frequently mutated gene in cytogenetically normal acute myeloid leukemia (AML). In AML cells, NPM1 mutations result in abnormal cytoplasmic localization of the mutant protein (NPM1c). NPM1 mutations are founding genetic lesions, however it is unknown whether NPM1c is required to maintain the leukemic state. Here, we show that loss of NPM1c from the cytoplasm, either through nuclear relocalization or targeted degradation, results in downregulation of homeobox (HOX) genes, and differentiation and cell growth arrest of AML cells. Additionally, we show that HOX downregulation is the earliest transcriptional event following the loss of NPM1c from the cytoplasm, preceding and promoting differentiation. Finally, we show that XPO1 inhibition efficiently relocalizes NPM1c to the nucleus, enables differentiation and prolongs survival of Npm1c+ leukemic mice. We describe an exquisite dependency of NPM1-mutant AML cells on NPM1c, providing the rationale for the use of nuclear export inhibitors in AML with mutated NPM1.
2018-08-06 | GSE111178 | GEO
Project description:NPM1-mutated acute myeloid leukemia (AML) accounts for one third of AML in adults. NPM1-mutated AML maintenance depends on the interaction between mutated NPM1 (NPM1c) and the nuclear exporter Exportin 1 (XPO1). In this work, we show that continous XPO1 inhibition is necessary to achieve stable disruption of the NPM1c-XPO1 interaction and to induce HOX downregulation and differentiation of AML cells with mutated NPM1. In contrast, intermittent XPO1 inhibition only results in minimal transcriptional perturbation and limited antileukemic activity.
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Project description:Recent evidence suggests that inhibition of BET epigenetic readers may have clinical utility in hematological malignancies. We demonstrate the efficacy of the BET inhibitor I-BET151 across a variety of AML subtypes, and demonstrate that a common core transcriptional program, which is HOX gene-independent, is downregulated in AML subtypes sensitive to I-BET treatment. Focusing on the most common mutation in AML, we present evidence to suggest that wildtype NPM1 has an inhibitory influence on BRD4, which is relieved upon NPM1c mutation and cytosplasmic dislocation. NPM1c mutation allows upregulation of the core transcriptional program facilitating leukemia development, and this program is abrogated by I-BET therapy. Finally, we demonstrate the efficacy of I-BET151 in human cell lines, a unique murine model and in primary patient samples of NPM1c AML. This submission only includes samples from the human cell line.
2014-12-12 | E-MTAB-1443 | biostudies-arrayexpress
Project description:Mutation in nucleophosmin (NPM1) causes relocalization of this normally nucleolar protein to the cytoplasm (NPM1c+). Despite NPM1 mutation being the most common driver mutation in cytogenetically normal adult acute myeloid leukemia (AML), the mechanisms of NPM1c+-induced leukemogenesis remain unclear. Caspase-2 is a pro-apoptotic protein activated by NPM1 in the nucleolus. Here, we show that caspase-2 is also activated by NPM1c+ in the cytoplasm and DNA damage-induced apoptosis is caspase-2-dependent in NPM1c+ but not in NPM1wt AML cells. Strikingly, in NPM1c+ cells, caspase-2 loss results in profound cell cycle arrest, differentiation, and down-regulation of stem cell pathways that regulate pluripotency including impairment in the AKT/mTORC1 and Wnt signaling pathways, and inhibition of Rictor cleavage. In contrast, there were minimal differences in proliferation, differentiation, or the transcriptional profile of NPM1wt cells lacking caspase-2. Our results show that caspase-2 is essential for proliferation and self-renewal of AML cells expressing mutated NPM1. This study demonstrates that caspase-2 is a major effector of NPM1c+ function.
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Project description:Acute myeloid leukemia (AML) pathogenesis often involves a mutation in the NPM1 nucleolar chaperone, but the bases for its transforming properties and association with favorable outcome remain incompletely understood. Here we demonstrate that an oncogenic mutant form of NPM1 (NPM1c) hampers formation of PML nuclear bodies (NBs), key senescence effectors, and impairs mitochondrial function to drive an integrated stress response. Actinomycin D (ActD), an antibiotic with unambiguous clinical efficacy in relapsed/refractory NPM1c-AMLs, preferentially targets these primed mitochondria, activating cGAS signaling and boosting ROS production. The later restores PML NB formation to drive senescence of NPM1c-AMLs cells. Dual targeting of mitochondria by Venetoclax and ActD synergized for AML elimination. Our studies reveal a central role of mitochondria downstream of NPM1c and implicate a mitochondrial/ROS/PML/TP53 senescence pathway as a key effector of ActD-based, and possibly others, chemotherapies.
2021-12-17 | PXD025507 | Pride
Project description:Acute Myeloid Leukemia (AML) is frequently associated with mutations of NPM1 (NPM1c+) and even if considered to be of better prognosis for younger patients, relapse is frequent and outcome remains poor for elder patients with a need for novel treatment strategies. Differentiation-based therapy by all trans retinoic acid (ATRA) combined with arsenic trioxide (ATO) induce proteasomal degradation of NPM1c protein, NPM1 nuclear re localization, differentiation and apoptosis in NPM1c+ cells and blast clearance in relapsed/refractory AML patients. In line, the XPO1 inhibitor Selinexor showed similar results in vitro associated with down regulation of a specific HOX gene signature. BET inhibitors (BETi) OTX015 (MK-8628) and JQ1 yield antileukemic activity and here we demonstrate their effects in NPM1c+ leukemia cells compared to ATO+ATRA and Selinexor. Compared to ATO+ATRA and Selinexor, BRDi induced TP53 independent apoptosis, differentiation, proteasomal NPM1c degradation and nuclear relocalization in NPM1c+ OCI-AML3 cell line and to different extend in patient derived blast cells. As ATO+ATRA and Selinexor had significant biological activity in NPM1c+ cell line IMS-M2, these cells were resistant to BETi exposure, except for nuclear re localization of NPM1 which is a general phenomenon upon treatment with all three drug types. Gene profiling revealed that BRDi downregulate a BRD specific core gene signature in OCI-AML3 and IMS-M2 cells but IMS-M2 cells yield a transcriptional resistance signature including upregulation of the Wnt/beta-catenin pathway. HOX gene clusters in OCI-AML3 cells and IMS-M2 cells are heterogeneously regulated by BETi and are down regulated by ATO+ATRA in line with results reported for Selinexor treatment. Taken together, our preclinical results encourage clinical testing of ATO+ATRA, Selinexor and BRDi in NPM1c+ AML patients.
2020-06-01 | GSE146362 | GEO
Project description:Nucleophosmin (NPM1) is a ubiquitously expressed nucleolar protein with a wide range of functions including ribosome biogenesis, mRNA processing, and maintenance of genomic stability1-4. In acute myeloid leukemia (AML), the terminal exon of NPM1 is often mutated (~30% of adult AMLs), resulting in the change of the nucleolar localization signal into a nuclear export signal and a shift of the protein to the cytoplasm (NPM1c)2,3,5. AMLs carrying this mutation have aberrant expression of the HOXA genes, whose overexpression leads to leukemogenic transformation6-8. Recently, it was shown that depletion or re-localization of the NPM1c protein into the nucleus causes downregulation of the HOXA genes, leading to the speculation that NPM1c directly regulates their transcription9-11. Here, we show that NPM1c binds to a subset of active gene promoters marked with high levels of H3K27ac in NPM1c leukemia cell lines and primary leukemia blasts, including well-known leukemia-driving genes such as posterior HOXA, HOXB, and MEIS1/PBX3 genes as well as novel targets IRX5 and NKX2-3. The binding of NPM1c on chromatin sustains active transcription of key target genes by maintaining high local-concentration of transcriptional complexes, including the Super Elongation Complex (SEC) and Menin/MLL1. NPM1c also maintains the active chromatin landscape by inhibiting the activity of histone deacetylases (HDACs). Depletion of NPM1c causes histone deacetylation and the silencing of key leukemic genes, leading to cell differentiation and growth arrest. The export protein XPO1 plays a key role by tethering NPM1c onto chromatin. The combination of XPO1 inhibitors (e.g., Selinexor and Eltanexor) with the Menin inhibitor MI-3454 has a synergistic effect on inducing differentiation in both NPM1-mutated leukemia cell lines and PDX model. Together, these findings reveal the neomorphic function of NPM1c as transactivator for leukemic gene expression and open up potential avenues for therapeutic intervention.
2022-02-27 | GSE197383 | GEO
Project description:Nucleophosmin (NPM1) is a ubiquitously expressed nucleolar protein with a wide range of functions including ribosome biogenesis, mRNA processing, and maintenance of genomic stability1-4. In acute myeloid leukemia (AML), the terminal exon of NPM1 is often mutated (~30% of adult AMLs), resulting in the change of the nucleolar localization signal into a nuclear export signal and a shift of the protein to the cytoplasm (NPM1c)2,3,5. AMLs carrying this mutation have aberrant expression of the HOXA genes, whose overexpression leads to leukemogenic transformation6-8. Recently, it was shown that depletion or re-localization of the NPM1c protein into the nucleus causes downregulation of the HOXA genes, leading to the speculation that NPM1c directly regulates their transcription9-11. Here, we show that NPM1c binds to a subset of active gene promoters marked with high levels of H3K27ac in NPM1c leukemia cell lines and primary leukemia blasts, including well-known leukemia-driving genes such as posterior HOXA, HOXB, and MEIS1/PBX3 genes as well as novel targets IRX5 and NKX2-3. The binding of NPM1c on chromatin sustains active transcription of key target genes by maintaining high local-concentration of transcriptional complexes, including the Super Elongation Complex (SEC) and Menin/MLL1. NPM1c also maintains the active chromatin landscape by inhibiting the activity of histone deacetylases (HDACs). Depletion of NPM1c causes histone deacetylation and the silencing of key leukemic genes, leading to cell differentiation and growth arrest. The export protein XPO1 plays a key role by tethering NPM1c onto chromatin. The combination of XPO1 inhibitors (e.g., Selinexor and Eltanexor) with the Menin inhibitor MI-3454 has a synergistic effect on inducing differentiation in both NPM1-mutated leukemia cell lines and PDX model. Together, these findings reveal the neomorphic function of NPM1c as transactivator for leukemic gene expression and open up potential avenues for therapeutic intervention.
2022-02-27 | GSE197367 | GEO