RESUMO
N-MYC (encoded by MYCN) is a critical regulator of hematopoietic stem cell function. While the role of N-MYC deregulation is well established in neuroblastoma, the importance of N-MYC deregulation in leukemogenesis remains elusive. Here, we demonstrate that N-MYC is overexpressed in acute myeloid leukemia (AML) cells with chromosome inversion inv(16) and contributes to the survival and maintenance of inv(16) leukemia. We identified a previously unknown MYCN enhancer, active in multiple AML subtypes, essential for MYCN mRNA levels and survival in inv(16) AML cells. We also identified eukaryotic translation initiation factor 4 gamma 1 (eIF4G1) as a key N-MYC target that sustains leukemic survival in inv(16) AML cells. The oncogenic role of eIF4G1 in AML has not been reported before. Our results reveal a mechanism whereby N-MYC drives a leukemic transcriptional program and provides a rationale for the therapeutic targeting of the N-MYC/eIF4G1 axis in myeloid leukemia.
Assuntos
Leucemia Mieloide Aguda , Humanos , Proteína Proto-Oncogênica N-Myc , Sobrevivência Celular/genética , Leucemia Mieloide Aguda/genética , Carcinogênese , Células-Tronco HematopoéticasRESUMO
The core binding factor composed of CBFß and RUNX subunits plays a critical role in most hematopoietic lineages and is deregulated in acute myeloid leukemia (AML). The fusion oncogene CBFß-SMMHC expressed in AML with the chromosome inversion inv(16)(p13q22) acts as a driver oncogene in hematopoietic stem cells and induces AML. This review focuses on novel insights regarding the molecular mechanisms involved in CBFß-SMMHC-driven leukemogenesis and recent advances in therapeutic approaches to target CBFß-SMMHC in inv(16) AML.
Assuntos
Transformação Celular Neoplásica/genética , Inversão Cromossômica , Cromossomos Humanos Par 16/genética , Subunidade beta de Fator de Ligação ao Core/genética , Imunoterapia/métodos , Leucemia Mieloide Aguda/tratamento farmacológico , Terapia de Alvo Molecular , Cadeias Pesadas de Miosina/genética , Proteínas de Fusão Oncogênica/antagonistas & inibidores , Animais , Antineoplásicos Imunológicos/uso terapêutico , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Cromossomos Humanos Par 16/ultraestrutura , Terapia Combinada , Subunidade alfa 2 de Fator de Ligação ao Core/deficiência , Subunidade alfa 2 de Fator de Ligação ao Core/metabolismo , Subunidade beta de Fator de Ligação ao Core/fisiologia , Previsões , Gemtuzumab/uso terapêutico , Regulação Leucêmica da Expressão Gênica , Técnicas de Introdução de Genes , Hematopoese/efeitos dos fármacos , Hematopoese/genética , Humanos , Leucemia Mieloide Aguda/genética , Camundongos , Células-Tronco Neoplásicas/efeitos dos fármacos , Células-Tronco Neoplásicas/metabolismo , Células-Tronco Neoplásicas/patologia , Proteínas de Fusão Oncogênica/genética , Proteínas de Fusão Oncogênica/fisiologia , Linfócitos T/imunologia , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
BACKGROUND: Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL/Apo2L) has been perceived as a promising anti-cancer agent because of its unique ability to kill cancer cells while sparing normal cells. However, translation of TRAIL to clinical studies was less successful as a large number of cancer cells acquire resistance to TRAIL-based monotherapies. An ideal strategy to overcome TRAIL resistance is to combine it with potential sensitizing agents. OBJECTIVE: To investigate the TRAIL-sensitizing effect of curcumin in leukemia. METHODS: The mechanism underlying TRAIL sensitization by curcumin was studied by flow cytometric analysis of TRAIL receptors in leukemic cell lines and patient samples, and immunoblot detection of TRAIL-apoptosis signaling proteins. RESULTS: Curcumin augments TRAIL-apoptotic signaling in leukemic cells by upregulating the expression of DR4 and DR5 along with suppression of cFLIP and anti-apoptotic proteins Mcl-1, Bcl-xl, and XIAP. Curcumin pre-treatment significantly (p < 0.01) enhanced the sensitivity of leukemic cell lines to TRAIL recombinant proteins. IL2-TRAIL peptide in the presence of curcumin induced potent apoptosis (p < 0.001) as compared to TRAIL and IL2-TRAIL protein in leukemic cell lines with IC50 < 0.1 µΜ. Additionally, the combination of IL2-TRAIL peptide and curcumin showed significant cytotoxicity in patient peripheral blood mononuclear cells (PBMCs) with an efficacy of 90% in acute myeloid leukemia (AML), but 100% in acute lymphoblastic leukemia (ALL), chronic lymphocytic leukemia (CLL) and chronic myelomonocytic leukemia (CMML). CONCLUSION: Overall, our results suggest that curcumin potentiates TRAIL-induced apoptosis through modulation of death receptors and anti-apoptotic proteins which significantly enhances the therapeutic efficacy.
