RESUMO
Gain-of-function kinase mutations are common in AML and usually portend an inferior prognosis. We reported a novel mechanism whereby kinase mutants induced intracellular alkalization characteristic in oncogenesis. Thirteen kinases were found to activate sodium/hydrogen exchanger (NHE1) in normal hematopoietic progenitors, of which FLT3-ITD, KRASG12D, and BTK phosphorylated NHE1 maintained alkaline intracellular pH (pHi) and supported survival of AML cells. Primary AML samples with kinase mutations also showed increased NHE1 phosphorylation and evidence of NHE1 addiction. Amiloride enhanced anti-leukemic effects and intracellular distribution of kinase inhibitors and chemotherapy. Co-inhibition of NHE1 and kinase synergistically acidified pHi in leukemia and inhibited its growth in vivo. Plasma from patients taking amiloride for diuresis reduced pHi of leukemia and enhanced cytotoxic effects of kinase inhibitors and chemotherapy in vitro. NHE1-mediated intracellular alkalization played a key pathogenetic role in transmitting the proliferative signal from mutated-kinase and could be exploited for therapeutic intervention in AML.
Assuntos
Amilorida , Antineoplásicos , Leucemia Mieloide Aguda , Amilorida/farmacologia , Amilorida/uso terapêutico , Antineoplásicos/farmacologia , Antineoplásicos/uso terapêutico , Mutação com Ganho de Função , Humanos , Leucemia Mieloide Aguda/tratamento farmacológico , Leucemia Mieloide Aguda/genética , Leucemia Mieloide Aguda/metabolismo , Leucemia Mieloide Aguda/patologia , Mutação , Inibidores de Proteínas Quinases/farmacologia , Inibidores de Proteínas Quinases/uso terapêutico , Proteínas Quinases/genética , Proteínas Quinases/metabolismo , Prótons , Transdução de Sinais , Tirosina Quinase 3 Semelhante a fms/genética , Tirosina Quinase 3 Semelhante a fms/uso terapêuticoRESUMO
ADP-ribosylation factor-like 4aa (Arl4aa) is a member of the ADP-ribosylation factor family. It is expressed in hematopoietic tissue during embryonic development, but its function was unknown. Zebrafish arl4aa is preferentially expressed in the ventral wall of the dorsal aorta (VDA) at 24 and 36 hpf and in caudal hematopoietic tissue at 48 hpf. Morpholino knockdown and transcription activator-like effector nuclease (TALEN) knockout of arl4aa significantly reduced expression of genes associated with definitive hematopoietic stem cells (HSCs). Golgi complex integrity in VDA was disrupted as shown by transmission electron microscopy and immunostaining of Golgi membrane Giantin. Mechanistically, arl4aa knockdown reduced Notch signaling in the VDA and its target gene expression. Protein expression of NICD was also reduced. Effects of arl4aa knockdown on definitive hematopoiesis could be restored by NICD expression. This study identified arl4aa as a factor regulating initiation of definitive HSCs by maintaining the integrity of Golgi complex and, secondarily, maturation of the Notch receptor.
Assuntos
Complexo de Golgi/metabolismo , Hemangioblastos/metabolismo , Hematopoese , Proteínas de Peixe-Zebra/metabolismo , Peixe-Zebra/metabolismo , Animais , Sequência de Bases , Sequência Conservada , Cruzamentos Genéticos , Regulação para Baixo , Células Endoteliais/metabolismo , Células Endoteliais/ultraestrutura , Humanos , Modelos Biológicos , Mutação/genética , Receptores Notch/metabolismo , Transdução de Sinais , Nucleases dos Efetores Semelhantes a Ativadores de TranscriçãoRESUMO
BACKGROUND: Omacetaxine mepesuccinate (OME) has antileukemic effects against acute myeloid leukemia (AML) carrying an internal tandem duplication of Fms-like tyrosine kinase 3 (FLT3-ITD). A phase 2 clinical trial was conducted to evaluate a combination treatment of sorafenib and omacetaxine mepesuccinate (SOME). METHODS: Relapsed or refractory (R/R) or newly diagnosed patients were treated with sorafenib (200-400 mg twice daily) and OME (2 mg daily) for 7 (first course) or 5 days (second course onward) every 21 days until disease progression or allogeneic hematopoietic stem cell transplantation (HSCT). The primary endpoint was composite complete remission, which was defined as complete remission (CR) plus complete remission with incomplete hematologic recovery (CRi). Secondary endpoints were leukemia-free survival (LFS) and overall survival (OS). RESULTS: Thirty-nine R/R patients and 5 newly diagnosed patients were recruited. Among the R/R patients, 28 achieved CR or CRi. Two patients showed partial remission, and 9 patients did not respond. Among the 5 newly diagnosed patients, 4 achieved CR, and 1 achieved CRi. The median LFS and OS were 5.6 and 10.9 months, respectively. Prior Fms-like tyrosine kinase 3 (FLT3) inhibitor exposure (P = .007), 2 or more inductions (P = .001), and coexisting IDH2 (P = .008) and RUNX1 mutations (P = .003) were associated with lower CR/CRi rates. HSCT consolidation and deep molecular responses (defined as an FLT3-ITD variant allelic frequency [VAF] ≤ 0.1% or a nucleophosmin 1 [NPM1] mutant VAF ≤ 0.01%) were associated with better OS and LFS. Prior FLT3 inhibitor exposure and 2 or more inductions were associated with inferior LFS. CONCLUSIONS: SOME was safe and effective for R/R and newly diagnosed FLT3-ITD AML.
Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/administração & dosagem , Mepesuccinato de Omacetaxina/administração & dosagem , Leucemia Mieloide Aguda/terapia , Recidiva Local de Neoplasia/terapia , Sorafenibe/administração & dosagem , Tirosina Quinase 3 Semelhante a fms/genética , Adulto , Idoso , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Protocolos de Quimioterapia Combinada Antineoplásica/farmacocinética , Progressão da Doença , Intervalo Livre de Doença , Esquema de Medicação , Resistencia a Medicamentos Antineoplásicos , Sinergismo Farmacológico , Éxons/genética , Feminino , Duplicação Gênica , Transplante de Células-Tronco Hematopoéticas , Mepesuccinato de Omacetaxina/efeitos adversos , Mepesuccinato de Omacetaxina/farmacocinética , Humanos , Leucemia Mieloide Aguda/genética , Leucemia Mieloide Aguda/mortalidade , Leucemia Mieloide Aguda/patologia , Masculino , Pessoa de Meia-Idade , Recidiva Local de Neoplasia/genética , Recidiva Local de Neoplasia/mortalidade , Recidiva Local de Neoplasia/patologia , Nucleofosmina , Indução de Remissão/métodos , Sorafenibe/efeitos adversos , Sorafenibe/farmacocinética , Transplante Homólogo , Adulto Jovem , Tirosina Quinase 3 Semelhante a fms/antagonistas & inibidores , Tirosina Quinase 3 Semelhante a fms/farmacocinéticaRESUMO
The present study aimed to define a subtype of complex/monosomal karyotype (CK/MK) acute myeloid leukemia (AML) by its distinct clinical features, p53 signaling and responses to p53 targeting agents. Ninety-eight young adults (range: 21-60 years; median: 49 years) with CK/MK AML were studied. They received standard induction, consolidation and allogeneic hematopoietic stem cell transplantation from siblings or matched unrelated donors if available. Chromosomal abnormalities most commonly affected chromosome 5 (30%), 7 (22%) and 17 (21%). Next generation sequencing of a 54-myeloid gene panel were available in 76 patients. Tumor protein 53 (TP53) mutations were most common (49%) and associated with the presence of -5/5q- (P < .001) and -17/17p- (P < .001), but not -7/7q- (P = .370). This "typical" CK/MK AML subtype was associated with significantly lower presenting white cell counts, higher number of karyotypic abnormalities, and inferior leukemia-free and overall survivals, compared with CK/MK AML without the typical features. Blood or bone marrow samples from typical CK/MK AML patients showed defective p53 signaling upon induction by etoposide. In vitro drug sensitivity analysis showed that they were sensitive to APR-246 that targeted mutant p53, but resistant to MDM2 antagonist MI-77301. Novel therapeutic strategies targeting TP53 mutations in CK/MK AML should be developed and tested in clinical trials.
Assuntos
Cariótipo Anormal , Antineoplásicos/administração & dosagem , Cromossomos Humanos , Resistencia a Medicamentos Antineoplásicos , Leucemia Mieloide Aguda , Monossomia , Proteína Supressora de Tumor p53 , Adolescente , Adulto , Cromossomos Humanos/genética , Cromossomos Humanos/metabolismo , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Resistencia a Medicamentos Antineoplásicos/genética , Feminino , Humanos , Leucemia Mieloide Aguda/tratamento farmacológico , Leucemia Mieloide Aguda/genética , Leucemia Mieloide Aguda/metabolismo , Leucemia Mieloide Aguda/patologia , Masculino , Pessoa de Meia-Idade , Proteína Supressora de Tumor p53/genética , Proteína Supressora de Tumor p53/metabolismoRESUMO
An in vitro drug-screening platform on patient samples was developed and validated to design personalized treatment for relapsed/refractory acute myeloid leukemia (AML). Unbiased clustering and correlation showed that homoharringtonine (HHT), also known as omacetaxine mepesuccinate, exhibited preferential antileukemia effect against AML carrying internal tandem duplication of fms-like tyrosine kinase 3 (FLT3-ITD). It worked synergistically with FLT3 inhibitors to suppress leukemia growth in vitro and in xenograft mouse models. Mechanistically, the effect was mediated by protein synthesis inhibition and reduction of short-lived proteins, including total and phosphorylated forms of FLT3 and its downstream signaling proteins. A phase 2 clinical trial of sorafenib and HHT combination treatment in FLT3-ITD AML patients resulted in complete remission (true or with insufficient hematological recovery) in 20 of 24 patients (83.3%), reduction of ITD allelic burden, and median leukemia-free and overall survivals of 12 and 33 weeks. The regimen has successfully bridged five patients to allogeneic hematopoietic stem cell transplantation and was well tolerated in patients unfit for conventional chemotherapy, including elderly and heavily pretreated patients. This study validated the principle and clinical relevance of in vitro drug testing and identified an improved treatment for FLT3-ITD AML. The results provided the foundation for phase 2/3 clinical trials to ascertain the clinical efficacy of FLT3 inhibitors and HHT in combination.