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Multivariable analysis for overall survival and relapse-free survival demonstrating lack of significant for D14 BM status.
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Somatic mutations in the isocitrate dehydrogenase 2 gene (IDH2) contribute to the pathogenesis of acute myeloid leukaemia (AML) through the production of the oncometabolite 2-hydroxyglutarate (2HG)1-8. Enasidenib (AG-221) is an allosteric inhibitor that binds to the IDH2 dimer interface and blocks the production of 2HG by IDH2 mutants9,10. In a phase I/II clinical trial, enasidenib inhibited the production of 2HG and induced clinical responses in relapsed or refractory IDH2-mutant AML11. Here we describe two patients with IDH2-mutant AML who had a clinical response to enasidenib followed by clinical resistance, disease progression, and a recurrent increase in circulating levels of 2HG. We show that therapeutic resistance is associated with the emergence of second-site IDH2 mutations in trans, such that the resistance mutations occurred in the IDH2 allele without the neomorphic R140Q mutation. The in trans mutations occurred at glutamine 316 (Q316E) and isoleucine 319 (I319M), which are at the interface where enasidenib binds to the IDH2 dimer. The expression of either of these mutant disease alleles alone did not induce the production of 2HG; however, the expression of the Q316E or I319M mutation together with the R140Q mutation in trans allowed 2HG production that was resistant to inhibition by enasidenib. Biochemical studies predicted that resistance to allosteric IDH inhibitors could also occur via IDH dimer-interface mutations in cis, which was confirmed in a patient with acquired resistance to the IDH1 inhibitor ivosidenib (AG-120). Our observations uncover a mechanism of acquired resistance to a targeted therapy and underscore the importance of 2HG production in the pathogenesis of IDH-mutant malignancies.
Assuntos
Aminopiridinas/farmacologia , Resistencia a Medicamentos Antineoplásicos/genética , Isocitrato Desidrogenase/antagonistas & inibidores , Isocitrato Desidrogenase/genética , Leucemia Mieloide Aguda/genética , Proteínas Mutantes/genética , Mutação , Multimerização Proteica/genética , Triazinas/farmacologia , Alelos , Sítio Alostérico/efeitos dos fármacos , Sítio Alostérico/genética , Aminopiridinas/química , Aminopiridinas/uso terapêutico , Animais , Ensaios Clínicos Fase I como Assunto , Ensaios Clínicos Fase II como Assunto , Progressão da Doença , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Inibidores Enzimáticos/química , Inibidores Enzimáticos/farmacologia , Inibidores Enzimáticos/uso terapêutico , Feminino , Glutamina/genética , Glutaratos/sangue , Glutaratos/metabolismo , Células HEK293 , Humanos , Isoleucina/genética , Leucemia Mieloide Aguda/sangue , Leucemia Mieloide Aguda/tratamento farmacológico , Camundongos , Camundongos Endogâmicos C57BL , Modelos Moleculares , Proteínas Mutantes/antagonistas & inibidores , Triazinas/química , Triazinas/uso terapêuticoRESUMO
We present a highly sensitive and selective chemical labeling and capture approach for genome-wide profiling of 5-hydroxylmethylcytosine (5hmC) using DNA isolated from â¼1,000 cells (nano-hmC-Seal). Using this technology, we assessed 5hmC occupancy and dynamics across different stages of hematopoietic differentiation. Nano-hmC-Seal profiling of purified Tet2-mutant acute myeloid leukemia (AML) murine stem cells allowed us to identify leukemia-specific, differentially hydroxymethylated regions that harbor known and candidate disease-specific target genes with differential 5hmC peaks compared to normal stem cells. The change of 5hmC patterns in AML strongly correlates with differential gene expression, demonstrating the importance of dynamic alterations of 5hmC in regulating transcription in AML. Together, covalent 5hmC labeling offers an effective approach to study and detect DNA methylation dynamics in in vivo disease models and in limited clinical samples.
Assuntos
5-Metilcitosina/análogos & derivados , Metilação de DNA , Epigênese Genética , Perfilação da Expressão Gênica/métodos , Hematopoese/genética , Células-Tronco Hematopoéticas/metabolismo , Sequenciamento de Nucleotídeos em Larga Escala/métodos , Leucemia Promielocítica Aguda/genética , 5-Metilcitosina/metabolismo , Animais , Células Cultivadas , Biologia Computacional , Proteínas de Ligação a DNA/genética , Bases de Dados Genéticas , Dioxigenases , Regulação Neoplásica da Expressão Gênica , Biblioteca Gênica , Estudo de Associação Genômica Ampla , Leucemia Promielocítica Aguda/metabolismo , Camundongos , Mutação , Nanotecnologia , Proteínas Proto-Oncogênicas/genética , Fatores de Tempo , Tirosina Quinase 3 Semelhante a fms/genéticaRESUMO
Recent studies have reported that activation-induced cytidine deaminase (AID) and ten-eleven-translocation (TET) family members regulate active DNA demethylation. Genetic alterations of TET2 occur in myeloid malignancies, and hematopoietic-specific loss of Tet2 induces aberrant hematopoietic stem cell (HSC) self-renewal/differentiation, implicating TET2 as a master regulator of normal and malignant hematopoiesis. Despite the functional link between AID and TET in epigenetic gene regulation, the role of AID loss in hematopoiesis and myeloid transformation remains to be investigated. Here, we show that Aid loss in mice leads to expansion of myeloid cells and reduced erythroid progenitors resulting in anemia, with dysregulated expression of Cebpa and Gata1, myeloid/erythroid lineage-specific transcription factors. Consistent with data in the murine context, silencing of AID in human bone marrow cells skews differentiation toward myelomonocytic lineage. However, in contrast to Tet2 loss, Aid loss does not contribute to enhanced HSC self-renewal or cooperate with Flt3-ITD to induce myeloid transformation. Genome-wide transcription and differential methylation analysis uncover the critical role of Aid as a key epigenetic regulator. These results indicate that AID and TET2 share common effects on myeloid and erythroid lineage differentiation, however, their role is nonredundant in regulating HSC self-renewal and in myeloid transformation.
Assuntos
Diferenciação Celular , Citidina Desaminase/fisiologia , Metilação de DNA , Células-Tronco Hematopoéticas/metabolismo , Animais , Linhagem da Célula , Autorrenovação Celular , Transformação Celular Neoplásica , Citidina Desaminase/genética , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/fisiologia , Dioxigenases , Células Eritroides/citologia , Inativação Gênica , Células-Tronco Hematopoéticas/citologia , Humanos , Camundongos , Células Mieloides/citologia , Proteínas Proto-Oncogênicas/genética , Proteínas Proto-Oncogênicas/fisiologiaRESUMO
TET proteins convert 5-methylcytosine to 5-hydroxymethylcytosine, an emerging dynamic epigenetic state of DNA that can influence transcription. Evidence has linked TET1 function to epigenetic repression complexes, yet mechanistic information, especially for the TET2 and TET3 proteins, remains limited. Here, we show a direct interaction of TET2 and TET3 with O-GlcNAc transferase (OGT). OGT does not appear to influence hmC activity, rather TET2 and TET3 promote OGT activity. TET2/3-OGT co-localize on chromatin at active promoters enriched for H3K4me3 and reduction of either TET2/3 or OGT activity results in a direct decrease in H3K4me3 and concomitant decreased transcription. Further, we show that Host Cell Factor 1 (HCF1), a component of the H3K4 methyltransferase SET1/COMPASS complex, is a specific GlcNAcylation target of TET2/3-OGT, and modification of HCF1 is important for the integrity of SET1/COMPASS. Additionally, we find both TET proteins and OGT activity promote binding of the SET1/COMPASS H3K4 methyltransferase, SETD1A, to chromatin. Finally, studies in Tet2 knockout mouse bone marrow tissue extend and support the data as decreases are observed of global GlcNAcylation and also of H3K4me3, notably at several key regulators of haematopoiesis. Together, our results unveil a step-wise model, involving TET-OGT interactions, promotion of GlcNAcylation, and influence on H3K4me3 via SET1/COMPASS, highlighting a novel means by which TETs may induce transcriptional activation.
Assuntos
Metilação de DNA , Proteínas de Ligação a DNA/metabolismo , Dioxigenases/metabolismo , Regulação da Expressão Gênica , Histona-Lisina N-Metiltransferase/metabolismo , N-Acetilglucosaminiltransferases/metabolismo , Proteínas Proto-Oncogênicas/metabolismo , Transcrição Gênica , 5-Metilcitosina/metabolismo , Sequência de Aminoácidos , Animais , Western Blotting , Proliferação de Células , Células Cultivadas , Imunoprecipitação da Cromatina , Ilhas de CpG , Citosina/análogos & derivados , Citosina/metabolismo , Epigênese Genética , Glicosilação , Histonas/metabolismo , Fator C1 de Célula Hospedeira/metabolismo , Humanos , Imunoprecipitação , Camundongos , Camundongos Knockout , Dados de Sequência Molecular , Regiões Promotoras Genéticas/genéticaRESUMO
We report the first case of pacritinib-withdrawal syndrome with in vitro elucidation of underlying mechanisms.
Assuntos
Mielofibrose Primária , Humanos , Hidrocarbonetos Aromáticos com Pontes , Pirimidinas , Janus Quinase 2/genéticaRESUMO
Clonal hematopoiesis (CH) is a common premalignant state in the blood and confers an increased risk of blood cancers and all-cause mortality. Identification of therapeutic targets in CH has been hindered by the lack of an ex vivo platform amenable for studying primary hematopoietic stem and progenitor cells (HSPCs). Here, we utilize an ex vivo co-culture system of HSPCs with bone marrow endothelial cells to perform CRISPR/Cas9 screens in mutant HSPCs. Our data reveal that loss of the histone demethylase family members Kdm3b and Jmjd1c specifically reduces the fitness of Idh2- and Tet2-mutant HSPCs. Kdm3b loss in mutant cells leads to decreased expression of critical cytokine receptors including Mpl, rendering mutant HSPCs preferentially susceptible to inhibition of downstream JAK2 signaling. Our study nominates an epigenetic regulator and an epigenetically regulated receptor signaling pathway as genotype-specific therapeutic targets and provides a scalable platform to identify genetic dependencies in mutant HSPCs.
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Therapy-related myelodysplastic syndromes and acute myelogenous leukemia comprise a poor-risk subset of myelodysplastic syndromes and acute myelogenous leukemia. Large-scale mutation profiling efforts in de novo myelodysplastic syndromes have identified mutations that correlate with clinical features, but such mutations have not been investigated in therapy-related myelodysplastic syndromes and acute myelogenous leukemia. Genomic DNA from 38 patient samples were subjected to high throughput polymerase chain reaction and sequenced for TP53, TET2, DNMT3A, ASXL1, IDH1, IDH2, EZH2, EED, SUZ12, RBBP4, SRSF2, U2AF35, and SF3B1. We identified somatic mutations in 16 of 38 (42%) patients. TP53 mutations were the most common lesion, detected in 8 of 38 (21%) patients, followed by TET2 in 4 of 38 (10.5%). Cases with a TP53 mutation or loss of the TP53 locus had a worse overall survival compared to those with wild-type TP53 (8.8 vs. 37.4 months; P=0.0035).
Assuntos
Análise Mutacional de DNA , Leucemia Mieloide Aguda/genética , Mutação , Síndromes Mielodisplásicas/genética , Adulto , Idoso , Idoso de 80 Anos ou mais , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Feminino , Humanos , Leucemia Mieloide Aguda/etiologia , Leucemia Mieloide Aguda/mortalidade , Leucemia Mieloide Aguda/terapia , Masculino , Pessoa de Meia-Idade , Taxa de Mutação , Síndromes Mielodisplásicas/etiologia , Síndromes Mielodisplásicas/mortalidade , Síndromes Mielodisplásicas/terapia , Prognóstico , Radioterapia/efeitos adversos , Proteína Supressora de Tumor p53/genéticaRESUMO
In acute myeloid leukemia (AML), p53 tumor suppressor activity can be reduced due to enhanced expression of MDM2 which promotes the degradation of p53. In TP53 wild-type malignancies, therapy with small molecule antagonists of MDM2 results in antileukemic activity. Current treatment strategies, however, have been limited by poor tolerability and incomplete clinical activity. We have developed a proteolysis-targeting chimera (PROTAC) MS3227 that targets MDM2 by recruiting the E3 ligase Von Hippel-Lindau, resulting in proteasome-dependent degradation of MDM2. In WT TP53 leukemia cell lines, MS3227 led to activation of p53 targets p21, PUMA, and MDM2 and resulted in cell-cycle arrest, apoptosis, and decreased viability. The catalytic PROTAC MS3227 led to more potent activation when compared to a stoichiometric inhibitor, in part by dampening the negative feedback mechanism in the p53 - MDM2 circuit. The effectiveness of MS3227 was also observed in primary patient specimens with selectivity towards leukemic blasts. The addition of MS3227 enhanced the activity of other anti-leukemic agents including azacytidine, cytarabine, and venetoclax. In particular, MS3227 treatment was shown to downregulate MCL-1, a known mediator of resistance to venetoclax. A PROTAC-based approach may provide a means of improving MDM2 inhibition to gain greater therapeutic potential in AML.
Assuntos
Leucemia Mieloide Aguda , Proteína Supressora de Tumor p53 , Humanos , Proteína Supressora de Tumor p53/genética , Proteína Supressora de Tumor p53/metabolismo , Proteínas Proto-Oncogênicas c-mdm2/metabolismo , Compostos Bicíclicos Heterocíclicos com Pontes/uso terapêutico , Leucemia Mieloide Aguda/tratamento farmacológico , Leucemia Mieloide Aguda/genética , Leucemia Mieloide Aguda/metabolismo , Apoptose , Linhagem Celular TumoralRESUMO
Myeloproliferative neoplasms, such as polycythemia vera, essential thrombocythemia, and primary myelofibrosis, are bone marrow disorders that result in the overproduction of mature clonal myeloid elements. Identification of recurrent genetic mutations has been described and aid in diagnosis and prognostic determination. Mouse models of these mutations have confirmed the biologic significance of these mutations in myeloproliferative neoplasm disease biology and provided greater insights on the pathways that are dysregulated with each mutation. The models are useful tools that have led to preclinical testing and provided data as validation for future myeloproliferative neoplasm clinical trials.
Assuntos
Modelos Animais de Doenças , Transtornos Mieloproliferativos , Neoplasias , Animais , Camundongos , Mutação , Transtornos Mieloproliferativos/diagnóstico , Transtornos Mieloproliferativos/genética , Neoplasias/diagnóstico , Neoplasias/genéticaRESUMO
Hypomethylating agents (HMAs) in combination with venetoclax have been widely adopted as the standard of care for patients who cannot tolerate induction chemotherapy and for patients who have relapsed/refractory (R/R) acute myeloid leukemia (AML). This study retrospectively analyzed the outcomes of all patients with AML (n = 65) or myelodysplastic syndrome (n = 7) who received the combination of HMA and venetoclax at our institution. Outcomes measured included complete remission (CR) and CR with incomplete hematologic recovery (CRi) rates, duration of response (DOR), and overall survival (OS). Patient mutational profiles and transfusion requirements were also assessed. Of 26 newly diagnosed AML patients, the CR/CRi rate was 53.8%. The median DOR and OS were 6.9 months and not reached, respectively. Of 39 R/R AML patients, the CR/CRi rate was 38.5%. The median DOR and OS were both 8.1 months. Responders to HMA and venetoclax were enriched for TET2, IDH1, and IDH2 mutations, while nonresponders were associated with FLT3 and RAS mutations. Adaptive resistance was observed through various mechanisms including acquired RAS pathway mutations. Of transfusion-dependent patients, 12.2% and 15.2% achieved red blood cell (RBC) and platelet transfusion independence, respectively, while 44.8% and 35.1% of RBC and platelet transfusion independent patients, respectively, became transfusion dependent. In total 59.1% of patients developed a ≥grade 3 infection and 46.5% neutropenic fever. HMA + venetoclax can lead to impressive response rates with moderately durable remissions and survival. However, the benefits of this combination are diminished by the significant toxicities from infection, persistent cytopenias, and transfusion requirements.
RESUMO
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 TET2 or IDH2 mutations show that epiallele diversity is especially strongly induced by IDH 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 TET2/IDH2, 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.This article is highlighted in the In This Issue feature, p. 1775.
Assuntos
Epigênese Genética/genética , Leucemia Mieloide Aguda/genética , Feminino , Humanos , Leucemia Mieloide Aguda/patologia , Masculino , MutaçãoRESUMO
Isocitrate dehydrogenase 1 (IDH1) is important for reductive carboxylation in cancer cells, and the IDH1 R132H mutation plays a pathogenic role in cancers including acute myeloid leukemia (AML). However, the regulatory mechanisms modulating mutant and/or wild-type (WT) IDH1 function remain unknown. Here, we show that two groups of tyrosine kinases (TK) enhance the activation of mutant and WT IDH1 through preferential Y42 or Y391 phosphorylation. Mechanistically, Y42 phosphorylation occurs in IDH1 monomers, which promotes dimer formation with enhanced substrate (isocitrate or α-ketoglutarate) binding, whereas Y42-phosphorylated dimers show attenuated disruption to monomers. Y391 phosphorylation occurs in both monomeric and dimeric IDH1, which enhances cofactor (NADP+ or NADPH) binding. Diverse oncogenic TKs phosphorylate IDH1 WT at Y42 and activate Src to phosphorylate IDH1 at Y391, which contributes to reductive carboxylation and tumor growth, whereas FLT3 or the FLT3-ITD mutation activates JAK2 to enhance mutant IDH1 activity through phosphorylation of Y391 and Y42, respectively, in AML cells. SIGNIFICANCE: We demonstrated an intrinsic connection between oncogenic TKs and activation of WT and mutant IDH1, which involves distinct TK cascades in related cancers. In particular, these results provide an additional rationale supporting the combination of FLT3 and mutant IDH1 inhibitors as a promising clinical treatment of mutant IDH1-positive AML.See related commentary by Horton and Huntly, p. 699.This article is highlighted in the In This Issue feature, p. 681.
Assuntos
Isocitrato Desidrogenase/genética , Mutação , Neoplasias/genética , Neoplasias/metabolismo , Proteínas Tirosina Quinases/metabolismo , Linhagem Celular Tumoral , Gerenciamento Clínico , Humanos , Isocitrato Desidrogenase/química , Janus Quinase 2/metabolismo , Modelos Biológicos , NADP/metabolismo , Neoplasias/patologia , Fosforilação , Ligação Proteica , Multimerização Proteica , Tirosina Quinase 3 Semelhante a fms/genéticaRESUMO
Disruption of epigenetic regulation is a hallmark of acute myeloid leukemia (AML), but epigenetic therapy is complicated by the complexity of the epigenome. Herein, we developed a long-term primary AML ex vivo platform to determine whether targeting different epigenetic layers with 5-azacytidine and LSD1 inhibitors would yield improved efficacy. This combination was most effective in TET2 mut AML, where it extinguished leukemia stem cells and particularly induced genes with both LSD1-bound enhancers and cytosine-methylated promoters. Functional studies indicated that derepression of genes such as GATA2 contributes to drug efficacy. Mechanistically, combination therapy increased enhancer-promoter looping and chromatin-activating marks at the GATA2 locus. CRISPRi of the LSD1-bound enhancer in patient-derived TET2 mut AML was associated with dampening of therapeutic GATA2 induction. TET2 knockdown in human hematopoietic stem/progenitor cells induced loss of enhancer 5-hydroxymethylation and facilitated LSD1-mediated enhancer inactivation. Our data provide a basis for rational targeting of cooperating aberrant promoter and enhancer epigenetic marks driven by mutant epigenetic modifiers. SIGNIFICANCE: Somatic mutations of genes encoding epigenetic modifiers are a hallmark of AML and potentially disrupt many components of the epigenome. Our study targets two different epigenetic layers at promoters and enhancers that cooperate to aberrant gene silencing, downstream of the actions of a mutant epigenetic regulator.This article is highlighted in the In This Issue feature, p. 813.
Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/farmacologia , Histona Desmetilases/antagonistas & inibidores , Histona Desmetilases/genética , Leucemia Mieloide Aguda/tratamento farmacológico , Leucemia Mieloide Aguda/genética , Animais , Azacitidina/farmacologia , DNA (Citosina-5-)-Metiltransferase 1/antagonistas & inibidores , Metilação de DNA/efeitos dos fármacos , Proteínas de Ligação a DNA/genética , Dioxigenases , Elementos Facilitadores Genéticos , Epigenoma , Fator de Transcrição GATA2/genética , Fator de Transcrição GATA2/metabolismo , Genes Supressores de Tumor , Humanos , Leucemia Mieloide Aguda/metabolismo , Leucemia Mieloide Aguda/patologia , Camundongos , Camundongos Endogâmicos NOD , Camundongos SCID , Células-Tronco Neoplásicas/metabolismo , Células-Tronco Neoplásicas/patologia , Regiões Promotoras Genéticas/efeitos dos fármacos , Proteínas Proto-Oncogênicas/genética , Distribuição Aleatória , Células Tumorais Cultivadas , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
Mutations in epigenetic modifiers and signaling factors often co-occur in myeloid malignancies, including TET2 and NRAS mutations. Concurrent Tet2 loss and NrasG12D expression in hematopoietic cells induced myeloid transformation, with a fully penetrant, lethal chronic myelomonocytic leukemia (CMML), which was serially transplantable. Tet2 loss and Nras mutation cooperatively led to decrease in negative regulators of mitogen-activated protein kinase (MAPK) activation, including Spry2, thereby causing synergistic activation of MAPK signaling by epigenetic silencing. Tet2/Nras double-mutant leukemia showed preferential sensitivity to MAPK kinase (MEK) inhibition in both mouse model and patient samples. These data provide insights into how epigenetic and signaling mutations cooperate in myeloid transformation and provide a rationale for mechanism-based therapy in CMML patients with these high-risk genetic lesions.
Assuntos
Proteínas de Ligação a DNA/genética , GTP Fosfo-Hidrolases/genética , Leucemia Mielomonocítica Crônica/genética , Proteínas de Membrana/genética , Proteínas Monoméricas de Ligação ao GTP/genética , Mutação/genética , Proteínas Proto-Oncogênicas/genética , Animais , Transformação Celular Neoplásica/genética , Dioxigenases , Humanos , Peptídeos e Proteínas de Sinalização Intracelular/genética , Camundongos Transgênicos , Transtornos Mieloproliferativos/genética , Proteínas Serina-Treonina Quinases , Transdução de Sinais/genéticaRESUMO
Patients with myeloproliferative neoplasms (MPNs) frequently progress to bone marrow failure or acute myeloid leukemia (AML), and mutations in epigenetic regulators such as the metabolic enzyme isocitrate dehydrogenase (IDH) are associated with poor outcomes. Here, we showed that combined expression of Jak2V617F and mutant IDH1R132H or Idh2R140Q induces MPN progression, alters stem/progenitor cell function, and impairs differentiation in mice. Jak2V617F Idh2R140Q-mutant MPNs were sensitive to small-molecule inhibition of IDH. Combined inhibition of JAK2 and IDH2 normalized the stem and progenitor cell compartments in the murine model and reduced disease burden to a greater extent than was seen with JAK inhibition alone. In addition, combined JAK2 and IDH2 inhibitor treatment also reversed aberrant gene expression in MPN stem cells and reversed the metabolite perturbations induced by concurrent JAK2 and IDH2 mutations. Combined JAK2 and IDH2 inhibitor therapy also showed cooperative efficacy in cells from MPN patients with both JAK2mut and IDH2mut mutations. Taken together, these data suggest that combined JAK and IDH inhibition may offer a therapeutic advantage in this high-risk MPN subtype.
Assuntos
Antineoplásicos/farmacologia , Regulação Neoplásica da Expressão Gênica , Isocitrato Desidrogenase/genética , Janus Quinase 2/genética , Transtornos Mieloproliferativos/tratamento farmacológico , Transtornos Mieloproliferativos/genética , Idoso , Animais , Progressão da Doença , Epigênese Genética , Feminino , Perfilação da Expressão Gênica , Humanos , Masculino , Camundongos , Camundongos Mutantes , Camundongos Transgênicos , Pessoa de Meia-Idade , Mutação , Fenótipo , Células-TroncoRESUMO
Somatic mutations in cytosolic or mitochondrial isoforms of isocitrate dehydrogenase (IDH1 or IDH2, respectively) contribute to oncogenesis via production of the metabolite 2-hydroxyglutarate (2HG). Isoform-selective IDH inhibitors suppress 2HG production and induce clinical responses in patients with IDH1- and IDH2-mutant malignancies. Despite the promising activity of IDH inhibitors, the mechanisms that mediate resistance to IDH inhibition are poorly understood. Here, we describe four clinical cases that identify mutant IDH isoform switching, either from mutant IDH1 to mutant IDH2 or vice versa, as a mechanism of acquired clinical resistance to IDH inhibition in solid and liquid tumors. SIGNIFICANCE: IDH-mutant cancers can develop resistance to isoform-selective IDH inhibition by "isoform switching" from mutant IDH1 to mutant IDH2 or vice versa, thereby restoring 2HG production by the tumor. These findings underscore a role for continued 2HG production in tumor progression and suggest therapeutic strategies to prevent or overcome resistance.This article is highlighted in the In This Issue feature, p. 1494.
Assuntos
Resistência a Medicamentos/genética , Isocitrato Desidrogenase/genética , Mutação , Doença Aguda , Adenocarcinoma/tratamento farmacológico , Adenocarcinoma/enzimologia , Adenocarcinoma/genética , Idoso , Inibidores Enzimáticos/farmacologia , Feminino , Humanos , Isocitrato Desidrogenase/antagonistas & inibidores , Isocitrato Desidrogenase/metabolismo , Isoenzimas/antagonistas & inibidores , Isoenzimas/genética , Isoenzimas/metabolismo , Leucemia Mieloide/tratamento farmacológico , Leucemia Mieloide/enzimologia , Leucemia Mieloide/genética , Neoplasias Hepáticas/tratamento farmacológico , Neoplasias Hepáticas/enzimologia , Neoplasias Hepáticas/genética , Masculino , Pessoa de Meia-Idade , Síndromes Mielodisplásicas/tratamento farmacológico , Síndromes Mielodisplásicas/enzimologia , Síndromes Mielodisplásicas/genéticaRESUMO
TET2 somatic mutations occur in â¼10% of diffuse large B-cell lymphomas (DLBCL) but are of unknown significance. Herein, we show that TET2 is required for the humoral immune response and is a DLBCL tumor suppressor. TET2 loss of function disrupts transit of B cells through germinal centers (GC), causing GC hyperplasia, impaired class switch recombination, blockade of plasma cell differentiation, and a preneoplastic phenotype. TET2 loss was linked to focal loss of enhancer hydroxymethylation and transcriptional repression of genes that mediate GC exit, such as PRDM1. Notably, these enhancers and genes are also repressed in CREBBP-mutant DLBCLs. Accordingly, TET2 mutation in patients yields a CREBBP-mutant gene-expression signature, CREBBP and TET2 mutations are generally mutually exclusive, and hydroxymethylation loss caused by TET2 deficiency impairs enhancer H3K27 acetylation. Hence, TET2 plays a critical role in the GC reaction, and its loss of function results in lymphomagenesis through failure to activate genes linked to GC exit signals. SIGNIFICANCE: We show that TET2 is required for exit of the GC, B-cell differentiation, and is a tumor suppressor for mature B cells. Loss of TET2 phenocopies CREBBP somatic mutation. These results advocate for sequencing TET2 in patients with lymphoma and for the testing of epigenetic therapies to treat these tumors.See related commentary by Shingleton and Dave, p. 1515.This article is highlighted in the In This Issue feature, p. 1494.
Assuntos
Diferenciação Celular/genética , Proteínas de Ligação a DNA/genética , Centro Germinativo/metabolismo , Linfoma Difuso de Grandes Células B/genética , Plasmócitos/metabolismo , Proteínas Proto-Oncogênicas/genética , Animais , Proteína de Ligação a CREB/genética , Proteína de Ligação a CREB/metabolismo , Proteínas de Ligação a DNA/metabolismo , Dioxigenases , Epigênese Genética/genética , Perfilação da Expressão Gênica/métodos , Centro Germinativo/patologia , Células-Tronco Hematopoéticas/metabolismo , Humanos , Hiperplasia , Linfoma Difuso de Grandes Células B/metabolismo , Linfoma Difuso de Grandes Células B/patologia , Camundongos Knockout , Camundongos Transgênicos , Mutação , Plasmócitos/patologia , Fator 1 de Ligação ao Domínio I Regulador Positivo/genética , Fator 1 de Ligação ao Domínio I Regulador Positivo/metabolismo , Proteínas Proto-Oncogênicas/metabolismoRESUMO
Genomic studies in acute myeloid leukemias (AML) have identified mutations that drive altered DNA methylation, including TET2 and IDH2 Here, we show that models of AML resulting from TET2 or IDH2 mutations combined with FLT3ITD mutations are sensitive to 5-azacytidine or to the IDH2 inhibitor AG-221, respectively. 5-azacytidine and AG-221 treatment induced an attenuation of aberrant DNA methylation and transcriptional output and resulted in a reduction in leukemic blasts consistent with antileukemic activity. These therapeutic benefits were associated with restoration of leukemic cell differentiation, and the normalization of hematopoiesis was derived from mutant cells. By contrast, combining AG-221 or 5-azacytidine with FLT3 inhibition resulted in a reduction in mutant allele burden, progressive recovery of normal hematopoiesis from non-mutant stem-progenitor cells, and reversal of dysregulated DNA methylation and transcriptional output. Together, our studies suggest combined targeting of signaling and epigenetic pathways can increase therapeutic response in AML.Significance: AMLs with mutations in TET2 or IDH2 are sensitive to epigenetic therapy through inhibition of DNA methyltransferase activity by 5-azacytidine or inhibition of mutant IDH2 through AG-221. These inhibitors induce a differentiation response and can be used to inform mechanism-based combination therapy. Cancer Discov; 7(5); 494-505. ©2017 AACR.See related commentary by Thomas and Majeti, p. 459See related article by Yen et al., p. 478This article is highlighted in the In This Issue feature, p. 443.