19 research outputs found
ActivitĂ© de l'acide tout-trans-rĂ©tinoĂŻque dans les leucĂ©mies aigĂŒes myĂ©loĂŻdes portant des mutations sur les isocitrate dĂ©shydrogĂ©nases : combinaisons et perspectives thĂ©rapeutiques
Les leucĂ©mies aigĂŒes myĂ©loĂŻdes (LAM) sont caractĂ©risĂ©es par l'accumulation de blastes leucĂ©miques pour lesquels les programmes de diffĂ©renciation sont dĂ©rĂ©gulĂ©s. Les mutations des isocitrate dĂ©shydrogĂ©nases (IDH), prĂ©sentes chez 15% des patients atteints de LAM Ă risque cytogĂ©nĂ©tique intermĂ©diaire, participent Ă cette dĂ©rĂ©gulation en induisant la production de R-2-Hydroxyglutarate (R-2-HG), responsable d'une hypermĂ©thylation globale de l'ADN. Nous avons identifiĂ© une signature gĂ©nique spĂ©cifique de la mutation IDH1 R132H, caractĂ©risĂ©e par une dĂ©rĂ©gulation des facteurs de transcription clĂ©s impliquĂ©s dans la diffĂ©renciation granulocytaire, mais Ă©galement par la dĂ©rĂ©gulation de gĂšnes rĂ©pondeurs Ă la diffĂ©renciation induite par l'ATRA. Nous avons montrĂ© que la mutation IDH1 R132H sensibilise les lignĂ©es cellulaires et blastes d'Ă©chantillons primaires de patients Ă la diffĂ©renciation induite par l'ATRA, Ă la fois in vitro et in vivo Ă des concentrations cliniquement relevantes. De plus, le traitement par une forme permĂ©ante du R-2-HG sensibilise la forme IDH1 WT Ă la diffĂ©renciation induite par l'ATRA, alors que l'inhibition de la production du R-2-HG rĂ©duit de façon significative les effets de l'ATRA dans la lignĂ©e HL60 IDH1 R132H. L'ATRA permet de diminuer la viabilitĂ© cellulaire et augmenter l'apoptose spĂ©cifiquement en prĂ©sence de la mutation IDH1 R132H, et conduit Ă une rĂ©duction drastique de la formation de colonies en milieu semi-solide. Il rĂ©duit Ă©galement la prise tumorale de la lignĂ©e MOLM14 IDH1 R132H xĂ©nogreffĂ©es dans des souris NOD-Scid-IL2rynull et augmente de façon trĂšs significative la survie globale des souris, rĂ©vĂ©lant l'effet potentiellement anti-leucĂ©mique de l'ATRA spĂ©cifiquement en prĂ©sence de la mutation IDH1 R132H. Nous avons Ă©galement mis en Ă©vidence un effet synergique entre l'ATRA et le dasatinib, spĂ©cifiquement en prĂ©sence de la mutation IDH1 R132H, Ă la fois in vitro et in vivo. Pour finir, nous avons montrĂ© que la mutation IDH1 R132H rĂ©duit la survie de souris xĂ©nogreffĂ©es par rapport Ă la forme sauvage, ainsi que la sensibilitĂ© in vitro aux chimiothĂ©rapies classiquement utilisĂ©es pour le traitement des LAM (AraC et Idarubicine). MalgrĂ© tout, l'ajout d'ATRA permet d'augmenter l'efficacitĂ© des chimiothĂ©rapies, spĂ©cifiquement en prĂ©sence de la mutation IDH1 R132H. Pour conclure, cette Ă©tude donne un rationnel pour tester ces combinaisons au cours de futurs essais cliniques dans ce sous-groupe de patients.Acute myeloid leukemia (AML) is characterized by accumulation of malignant blasts with impaired differentiation programs due to recurrent mutations such as isocitrate dehydrogenase (IDH) mutations found in 15% of AML patients. These mutations result in the production of (R)-2-hydroxyglutarate (2-HG), leading to a hypermethylation phenotype that impairs hematopoietic differentiation. Here we identified mutant IDH1-specific gene signatures regulated by key transcription factors involved in myeloid differentiation and responsive to retinoids. Accordingly, we showed that the presence of the IDH1 mutation sensitized AML cell lines and primary patient samples to all-trans retinoic acid (ATRA)-induced differentiation both in vitro and in vivo using clinically achievable doses. Moreover, treatment with a cell-permeable form of 2-HG sensitized wild-type IDH1 AML cells to ATRA-induced myeloid differentiation, while inhibition of 2-HG production significantly diminished ATRA effects in mutant IDH1 cells. ATRA treatment specifically decreased cell viability and induced apoptosis of mutant IDH1 blasts in vitro. ATRA also reduced tumor burden of mutant IDH1 AML cells xenografted in NOD-Scid-IL2rynull mice and highly increased mice overall survival, revealing a potent anti-leukemic effect of ATRA in the presence of IDH1 mutation. Moreover, we showed a synergistic effect between ATRA and dasatinib specifically in the presence of IDH1 R132H mutation, both in vitro and in vivo. Finally, we demonstrated that IDH1 R132H reduces survival of mice xenografted with mutant cell lines compared to the WT, and reduces sensitivity to chemotherapies (AraC and Idarubicine) in vitro. Nevertheless, the association of ATRA to chemotherapies increases their activity specifically in the presence of IDH1 R132H mutation. These therapeutic strategies hold promise for this AML patient subgroup in future clinical studies
The ROS/SUMO Axis Contributes to the Response of Acute Myeloid Leukemia Cells to Chemotherapeutic Drugs
Chemotherapeutic drugs used in the treatment of acute myeloid leukemias (AMLs) are thought to induce cancer cell death through the generation of DNA double-strand breaks. Here, we report that one of their early effects is the loss of conjugation of the ubiquitin-like protein SUMO from its targets via reactive oxygen species (ROS)-dependent inhibition of the SUMO-conjugating enzymes. Desumoylation regulates the expression of specific genes, such as the proapoptotic gene DDIT3, and helps induce apoptosis in chemosensitive AMLs. In contrast, chemotherapeutics do not activate the ROS/SUMO axis in chemoresistant cells. However, pro-oxidants or inhibition of the SUMO pathway by anacardic acid restores DDIT3 expression and apoptosis in chemoresistant cell lines and patient samples, including leukemic stem cells. Finally, inhibition of the SUMO pathway decreases tumor growth in mice xenografted with AML cells. Thus, targeting the ROS/SUMO axis might constitute a therapeutic strategy for AML patients resistant to conventional chemotherapies
Activation of Vitamin D Receptor Pathway Enhances Differentiating Capacity in Acute Myeloid Leukemia with Isocitrate Dehydrogenase Mutations
International audienceRelapses and resistance to therapeutic agents are major barriers in the treatment of acute myeloid leukemia (AML) patients. These unfavorable outcomes emphasize the need for new strategies targeting drug-resistant cells. As IDH mutations are present in the preleukemic stem cells and systematically conserved at relapse, targeting IDH mutant cells could be essential to achieve a long-term remission in the IDH mutant AML subgroup. Here, using a panel of human AML cell lines and primary AML patient specimens harboring IDH mutations, we showed that the production of an oncometabolite (R)-2-HG by IDH mutant enzymes induces vitamin D receptor-related transcriptional changes, priming these AML cells to differentiate with pharmacological doses of ATRA and/or VD. This activation occurs in a CEBPα-dependent manner. Accordingly, our findings illuminate potent and cooperative effects of IDH mutations and the vitamin D receptor pathway on differentiation in AML, revealing a novel therapeutic approach easily transferable/immediately applicable to this subgroup of AML patients
Isocitrate dehydrogenase 1 mutations prime the all-trans retinoic acid myeloid differentiation pathway in acute myeloid leukemia
International audienceAcute myeloid leukemia (AML) is characterized by the accumulation of malignant blasts with impaired differentiation programs caused by recurrent mutations, such as the isocitrate dehydrogenase (IDH) mutations found in 15% of AML patients. These mutations result in the production of the oncometabolite (R)-2-hydroxyglutarate (2-HG), leading to a hypermethylation phenotype that dysregulates hematopoietic differentiation. In this study, we identified mutant R132H IDH1-specific gene signatures regulated by key transcription factors, particularly CEBPα, involved in myeloid differentiation and retinoid responsiveness. We show that treatment with all-trans retinoic acid (ATRA) at clinically achievable doses markedly enhanced terminal granulocytic differentiation in AML cell lines, primary patient samples, and a xenograft mouse model carrying mutant IDH1. Moreover, treatment with a cell-permeable form of 2-HG sensitized wild-type IDH1 AML cells to ATRA-induced myeloid differentiation, whereas inhibition of 2-HG production significantly reduced ATRA effects in mutant IDH1 cells. ATRA treatment specifically decreased cell viability and induced apoptosis of mutant IDH1 blasts in vitro. ATRA also reduced tumor burden of mutant IDH1 AML cells xenografted in NOD-Scid-IL2rγ(null)mice and markedly increased overall survival, revealing a potent antileukemic effect of ATRA in the presence of IDH1 mutation. This therapeutic strategy holds promise for this AML patient subgroup in future clinical studies
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Sphingosine-1-Phosphate Receptor 3 Potentiates Inflammatory Programs in Normal and Leukemia Stem Cells to Promote Differentiation
Acute myeloid leukemia (AML) is a caricature of normal hematopoiesis, driven from leukemia stem cells (LSC) that share some hematopoietic stem cell (HSC) programs including responsiveness to inflammatory signaling. Although inflammation dysregulates mature myeloid cells and influences stemness programs and lineage determination in HSC by activating stress myelopoiesis, such roles in LSC are poorly understood. Here, we show that S1PR3, a receptor for the bioactive lipid sphingosine-1-phosphate, is a central regulator which drives myeloid differentiation and activates inflammatory programs in both HSC and LSC. S1PR3-mediated inflammatory signatures varied in a continuum from primitive to mature myeloid states across AML patient cohorts, each with distinct phenotypic and clinical properties. S1PR3 was high in LSC and blasts of mature myeloid samples with linkages to chemosensitivity, while S1PR3 activation in primitive samples promoted LSC differentiation leading to eradication. Our studies open new avenues for therapeutic target identification specific for each AML subset.J.E.D is supported by funds from the: Princess Margaret Cancer Centre Foundation, Ontario Institute for Cancer Research through funding provided by the Government of Ontario, Canadian Institutes for Health Research grants 130412, 89932, and 154293, International Development Research Centre Ottawa Canada grants 108401 and 109153, Canadian Cancer Society grant 703212, Terry Fox New Frontiers Program Project Grant 1047, University of Torontoâs Medicine by Design initiative with funding from the Canada First Research Excellence Fund, and a Canada Research Chair. E.L. is supported by Wellcome grant 107630/Z/15/Z and a core support grant from the Wellcome and MRC to the Wellcome-Medical Research Council Cambridge Stem Cell Institute. C.L. is supported by NIH, NCI grant P01-CA097132. W.W. was supported by the Swiss Initiative in Systems Biology Transition Postdoc fellowship
Dendrogenin A drives LXR to trigger lethal autophagy in cancers
International audienceDendrogenin A (DDA) is a newly discovered cholesterol metabolite with tumor suppressor properties. Here, we explored its efficacy and mechanism of cell death in melanoma and acute myeloid leukemia (AML). We found that DDA induced lethal autophagy in vitro and in vivo, including primary AML patient samples, independently of melanoma Braf status or AML molecular and cytogenetic classifications. DDA is a partial agonist on liver-X-receptor (LXR) increasing Nur77, Nor1, and LC3 expression leading to autolysosome formation. Moreover, DDA inhibited the cholesterol biosynthesizing enzyme 3ÎČ-hydroxysterol-Î8,7-isomerase (D8D7I) leading to sterol accumulation and cooperating in autophagy induction. This mechanism of death was not observed with other LXR ligands or D8D7I inhibitors establishing DDA selectivity. The potent anti-tumor activity of DDA, its original mechanism of action and its low toxicity support its clinical evaluation. More generally, this study reveals that DDA can direct control a nuclear receptor to trigger lethal autophagy in cancers
Chemotherapy-Resistant Human Acute Myeloid Leukemia Cells Are Not Enriched for Leukemic Stem Cells but Require Oxidative Metabolism
Comment inNovel Mitochondrial Mechanisms of Cytarabine Resistance in Primary AML Cells. [Cancer Discov. 2017]International audienceChemotherapy-resistant human acute myeloid leukemia (AML) cells are thought to be enriched in quiescent immature leukemic stem cells (LSC). To validate this hypothesis in vivo, we developed a clinically relevant chemotherapeutic approach treating patient-derived xenografts (PDX) with cytarabine (AraC). AraC residual AML cells are enriched in neither immature, quiescent cells nor LSCs. Strikingly, AraC-resistant preexisting and persisting cells displayed high levels of reactive oxygen species, showed increased mitochondrial mass, and retained active polarized mitochondria, consistent with a high oxidative phosphorylation (OXPHOS) status. AraC residual cells exhibited increased fatty-acid oxidation, upregulated CD36 expression, and a high OXPHOS gene signature predictive for treatment response in PDX and patients with AML. High OXPHOS but not low OXPHOS human AML cell lines were chemoresistant in vivo. Targeting mitochondrial protein synthesis, electron transfer, or fatty-acid oxidation induced an energetic shift toward low OXPHOS and markedly enhanced antileukemic effects of AraC. Together, this study demonstrates that essential mitochondrial functions contribute to AraC resistance in AML and are a robust hallmark of AraC sensitivity and a promising therapeutic avenue to treat AML residual disease.Significance: AraC-resistant AML cells exhibit metabolic features and gene signatures consistent with a high OXPHOS status. In these cells, targeting mitochondrial metabolism through the CD36-FAO-OXPHOS axis induces an energetic shift toward low OXPHOS and strongly enhanced antileukemic effects of AraC, offering a promising avenue to design new therapeutic strategies and fight AraC resistance in AML. Cancer Discov; 7(7); 716-35. ©2017 AACR.See related commentary by Schimmer, p. 670This article is highlighted in the In This Issue feature, p. 653
Figure S4 from Distinct Assemblies of Heterodimeric Cytokine Receptors Govern Stemness Programs in Leukemia
The IL-3R dodecamer activates STAT1 to induce cell differentiation.</p
Figure S3 from Distinct Assemblies of Heterodimeric Cytokine Receptors Govern Stemness Programs in Leukemia
IL3Rα P248 at the IL-3R assembly interface is critical for cell differentiation.</p