RESUMEN
Studies on the role of transcription factor MYB in acute myeloid leukemia (AML) have identified MYB as a key regulator of a transcriptional program for self-renewal of AML cells. Recent work summarized here has now highlighted the CCAAT-box/enhancer binding protein beta (C/EBPß) as an essential factor and potential therapeutic target that cooperates with MYB and coactivator p300 in the maintenance of the leukemic cells.
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Proteína beta Potenciadora de Unión a CCAAT , Leucemia Mieloide Aguda , Proteínas Oncogénicas v-myb , Humanos , Proteína beta Potenciadora de Unión a CCAAT/genética , Proteína beta Potenciadora de Unión a CCAAT/metabolismo , Regulación de la Expresión Génica , Leucemia Mieloide Aguda/genética , Proteínas Oncogénicas v-myb/genética , Proteínas Oncogénicas v-myb/metabolismoRESUMEN
Insulin-like growth factor 2 mRNA-binding protein 1 (IGF2BP1) is an oncofetal protein expressed in various cancers including leukemia. In this study, we assessed the role of IGF2BP1 in orchestrating leukemia stem cell properties. Tumor-initiating potential, sensitivity to chemotherapeutic agents, and expression of cancer stem cell markers were assessed in a panel of myeloid, B-, and T-cell leukemia cell lines using gain- and loss-of-function systems, cross-linking immunoprecipitation (CLIP), and photoactivatable ribonucleoside-enhanced cross-linking and immunoprecipitation (PAR-CLIP) techniques. Here, we report that genetic or chemical inhibition of IGF2BP1 decreases leukemia cells' tumorigenicity, promotes myeloid differentiation, increases leukemia cell death, and sensitizes leukemia cells to chemotherapeutic drugs. IGF2BP1 affects proliferation and tumorigenic potential of leukemia cells through critical regulators of self-renewal HOXB4 and MYB and through regulation of expression of the aldehyde dehydrogenase, ALDH1A1. Our data indicate that IGF2BP1 maintains leukemia stem cell properties by regulating multiple pathways of stemness through transcriptional and metabolic factors.
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Familia de Aldehído Deshidrogenasa 1/metabolismo , Regulación Leucémica de la Expresión Génica , Proteínas de Homeodominio/metabolismo , Leucemia Mieloide Aguda/patología , Células Madre Neoplásicas/patología , Proteínas Oncogénicas v-myb/metabolismo , Proteínas de Unión al ARN/metabolismo , Retinal-Deshidrogenasa/metabolismo , Factores de Transcripción/metabolismo , Familia de Aldehído Deshidrogenasa 1/genética , Animales , Antineoplásicos/farmacología , Apoptosis , Biomarcadores de Tumor , Proliferación Celular , Resistencia a Antineoplásicos , Femenino , Proteínas de Homeodominio/genética , Humanos , Leucemia Mieloide Aguda/tratamiento farmacológico , Leucemia Mieloide Aguda/genética , Leucemia Mieloide Aguda/metabolismo , Ratones , Ratones SCID , Células Madre Neoplásicas/metabolismo , Proteínas Oncogénicas v-myb/genética , Proteínas de Unión al ARN/genética , Retinal-Deshidrogenasa/genética , Factores de Transcripción/genética , Células Tumorales Cultivadas , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
BACKGROUND: This study was designed to evaluate the effects of micro-RNA-16 (miR-16)-regulated expression of myeloblastosis oncogene (MYB) on the differentiation of acute leukemia cells, the expressions of miR-16 and MYB mRNA, and protein in differently differentiated leukemia cells were detected by real-time PCR and western blot. METHODS: 1,25-Dihydroxyvitamin D3 (1,25 D3) induced monocytic differentiation of HL60 cells, and the resulting changes in miR-16 and MYB expressions were detected. Morphology of the cells induced by 1,25 D3, after being transfection with miR-16 mimics, was observed by Wright-Giemsa staining. The expression of mononuclear cell surface marker CD14 was detected by flow cytometry. RESULTS: Minimum miR-16 was expressed in early-differentiation KG-1a cells, while late-differentiation U937 and THP-1 cells had higher expressions (p < 0.01). The expressions of MYB changed oppositely. During the monocytic differentiation of HL60 cells, miR-16 expression showed a time-dependent increase, but MYB expression gradually decreased. Overexpression of miR-16 in HL60 cells promoted 1,25 D3-induced morphological changes and CD14 expression (p < 0.05). CONCLUSIONS: MR-16 facilitated the monocytic differentiation of leukemia HL60 cells by negatively regulating MYB expression.
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Diferenciación Celular/genética , Leucemia Mieloide/genética , MicroARNs/genética , Proteínas Oncogénicas v-myb/genética , Enfermedad Aguda , Calcitriol/farmacología , Diferenciación Celular/efectos de los fármacos , Línea Celular Tumoral , Perfilación de la Expresión Génica , Regulación Leucémica de la Expresión Génica/efectos de los fármacos , Células HL-60 , Humanos , Células K562 , Leucemia Mieloide/metabolismo , Leucemia Mieloide/patología , Proteínas Oncogénicas v-myb/metabolismo , Células THP-1 , Células U937RESUMEN
Drought is the most significant environmental stress for agricultural production worldwide, and tremendous efforts have been made to improve crop yield under the increasing water scarcity. Transcription factors are major players in the regulation of water stress-related genes in plants. Recently, different MYB transcription factors were characterized for their involvement in drought response. A sugarcane R2R3-MYB gene (ScMYBAS1) and its four alternative forms of transcript (ScMYAS1-2, ScMYBAS1-3, ScMYBAS1-4 and ScMYBAS1-5) were identified in this study. The subcellular localization, in Nicotiniana benthamiana, of the TFs fused in frame with GFP revealed that ScMYBAS1-2-GFP and ScMYBAS1-3-GFP were observed in the nucleus. The overexpression of ScMYBAS1-2 and ScMYBAS1-3 spliced transcripts in rice promoted change in plant growth under both well-watered and drought conditions. The ScMYBAS1-2 and ScMYBAS1-3 transgenic lines revealed a higher relative water content (RWC) compared to the wild type before maximum stress under drought conditions. The ScMYBAS1-2 transgenic lines showed a reduction in biomass (total dry weight). Conversely, ScMYBAS1-3 showed an increased biomass (total dry weight) relative to the wild-type. The overexpression of ScMYBAS1-3 in rice transgenic lines showed involvement with drought tolerance and biomass and, for this reason, was considered a good target for plant transformation, particularly for use in developing genotypes with drought tolerance and biomass accumulation.
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Proteínas Oncogénicas v-myb/genética , Oryza/genética , Saccharum/genética , Empalme Alternativo/genética , Biomasa , Sequías , Regulación de la Expresión Génica de las Plantas/genética , Genes myb/genética , Proteínas de Plantas , Plantas Modificadas Genéticamente/genética , Estrés Fisiológico/genética , Factores de Transcripción/genéticaRESUMEN
The major ß-haemoglobinopathies, sickle cell disease and ß-thalassaemia, represent the most common monogenic disorders worldwide and a steadily increasing global disease burden. Allogeneic haematopoietic stem cell transplantation, the only curative therapy, is only applied to a small minority of patients. Common clinical management strategies act mainly downstream of the root causes of disease. The observation that elevated fetal haemoglobin expression ameliorates these disorders has motivated longstanding investigations into the mechanisms of haemoglobin switching. Landmark studies over the last decade have led to the identification of two potent transcriptional repressors of γ-globin, BCL11A and ZBTB7A. These regulators act with additional trans-acting epigenetic repressive complexes, lineage-defining factors and developmental programs to silence fetal haemoglobin by working on cis-acting sequences at the globin gene loci. Rapidly advancing genetic technology is enabling researchers to probe deeply the interplay between the molecular players required for γ-globin (HBG1/HBG2) silencing. Gene therapies may enable permanent cures with autologous modified haematopoietic stem cells that generate persistent fetal haemoglobin expression. Ultimately rational small molecule pharmacotherapies to reactivate HbF could extend benefits widely to patients.
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Hemoglobinopatías/genética , Hemoglobinas/genética , Animales , Proteínas Portadoras/genética , Proteínas de Unión al ADN/genética , Modelos Animales de Enfermedad , Epigénesis Genética/genética , Globulinas Fetales/genética , Genes de Cambio/genética , Globinas/genética , Humanos , Factores de Transcripción de Tipo Kruppel/genética , Ratones , Proteínas Nucleares/genética , Proteínas Oncogénicas v-myb/genética , Proteínas Represoras , Factores de Transcripción/genéticaRESUMEN
Most E2F-binding sites repress transcription through the recruitment of Retinoblastoma (RB) family members until the end of the G1 cell-cycle phase. Although the MYB promoter contains an E2F-binding site, its transcription is activated shortly after the exit from quiescence, before RB family members inactivation, by unknown mechanisms. We had previously uncovered a nuclear factor distinct from E2F, Myb-sp, whose DNA-binding site overlapped the E2F element and had hypothesized that this factor might overcome the transcriptional repression of MYB by E2F-RB family members. We have purified Myb-sp and discovered that Myc-associated zinc finger proteins (MAZ) are major components. We show that various MAZ isoforms are present in Myb-sp and activate transcription via the MYB-E2F element. Moreover, while forced RB or p130 expression repressed the activity of a luciferase reporter driven by the MYB-E2F element, co-expression of MAZ proteins not only reverted repression, but also activated transcription. Finally, we show that MAZ binds the MYB promoter in vivo, that its binding site is critical for MYB transactivation, and that MAZ knockdown inhibits MYB expression during the exit from quiescence. Together, these data indicate that MAZ is essential to bypass MYB promoter repression by RB family members and to induce MYB expression.
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Proteínas de Unión al ADN/genética , Factores de Transcripción E2F/genética , Fase G1/genética , Regulación de la Expresión Génica , Proteínas Oncogénicas v-myb/genética , Regiones Promotoras Genéticas , Factores de Transcripción/genética , Sitios de Unión , Línea Celular Tumoral , Proteína Sustrato Asociada a CrK/genética , Proteína Sustrato Asociada a CrK/metabolismo , Proteínas de Unión al ADN/antagonistas & inhibidores , Proteínas de Unión al ADN/metabolismo , Factores de Transcripción E2F/metabolismo , Genes Reporteros , Células HEK293 , Humanos , Células Jurkat , Luciferasas/genética , Luciferasas/metabolismo , Linfocitos/citología , Linfocitos/metabolismo , Proteínas Oncogénicas v-myb/metabolismo , Osteoblastos/citología , Osteoblastos/metabolismo , Unión Proteica , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , ARN Interferente Pequeño/genética , ARN Interferente Pequeño/metabolismo , Proteína de Retinoblastoma/genética , Proteína de Retinoblastoma/metabolismo , Factores de Transcripción/antagonistas & inhibidores , Factores de Transcripción/metabolismo , Transcripción GenéticaRESUMEN
AIMS: Adenoid cystic carcinoma (AdCC) is one of the most common salivary gland malignancies and the long-term prognosis is poor. In this study, we examined alterations of AdCC-associated genes, MYB, MYBL1, MYBL2 and NFIB, and their target molecules, including MYC. The results were correlated to clinicopathological profile of the patients. METHODS AND RESULTS: Using paraffin tumour sections from 33 cases of salivary gland AdCC, we performed a detailed fluorescence in-situ hybridization (FISH) analysis for gene splits and fusions of MYB, MYBL1, MYBL2 and NFIB. We found that 29 of 33 (88%) AdCC cases showed gene splits in either MYB, MYBL1 or NFIB. None of the cases showed an MYBL2 gene alteration. AdCCs were divided genetically into six gene groups, MYB-NFIB (n = 16), MYB-X (n = 4), MYBL1-NFIB (n = 2), MYBL1-X (n = 1), NFIB-X (n = 6) and gene-split-negative (n = 4). AdCC patients showing the MYB or MYBL1 gene splits were associated with microscopically positive surgical margins (P = 0.0148) and overexpression of MYC (P = 0.0164). MYC expression was detected in both ductal and myoepithelial tumour cells, and MYC overexpression was associated with shorter disease-free survival of the patients (P = 0.0268). CONCLUSIONS: The present study suggests that (1) nearly 90% of AdCCs may have gene alterations of either MYB, MYBL1 or NFIB, suggesting the diagnostic utility of the FISH assay, (2) MYB or MYBL1 gene splits may be associated with local aggressiveness of the tumours and overexpression of MYC, which is one of the oncogenic MYB/MYBL1 targets and (3) MYC overexpression may be a risk factor for disease-free survival in AdCC.
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Biomarcadores de Tumor/genética , Carcinoma Adenoide Quístico/genética , Neoplasias de las Glándulas Salivales/genética , Adulto , Anciano , Anciano de 80 o más Años , Biomarcadores de Tumor/análisis , Carcinoma Adenoide Quístico/mortalidad , Carcinoma Adenoide Quístico/patología , Proteínas de Ciclo Celular/genética , Femenino , Genes myb , Humanos , Estimación de Kaplan-Meier , Masculino , Persona de Mediana Edad , Factores de Transcripción NFI/genética , Proteínas Oncogénicas v-myb/genética , Modelos de Riesgos Proporcionales , Proteínas Proto-Oncogénicas/genética , Proteínas Proto-Oncogénicas c-myc/genética , Neoplasias de las Glándulas Salivales/mortalidad , Neoplasias de las Glándulas Salivales/patología , Transactivadores/genética , Translocación GenéticaRESUMEN
Acute basophilic leukaemia (ABL) is a rare subtype of acute myeloblastic leukaemia. We previously described a recurrent t(X;6)(p11;q23) translocation generating an MYB-GATA1 fusion gene in male infants with ABL. To better understand its role, the chimeric MYB-GATA1 transcription factor was expressed in CD34-positive haematopoietic progenitors, which were transplanted into immunodeficient mice. Cells expressing MYB-GATA1 showed increased expression of markers of immaturity (CD34), of granulocytic lineage (CD33 and CD117), and of basophilic differentiation (CD203c and FcϵRI). UT-7 cells also showed basophilic differentiation after MYB-GATA1 transfection. A transcriptomic study identified nine genes deregulated by both MYB-GATA1 and basophilic differentiation. Induction of three of these genes (CCL23, IL1RL1, and NTRK1) was confirmed in MYB-GATA1-expressing CD34-positive cells by reverse transcription quantitative polymerase chain reaction. Interleukin (IL)-33 and nerve growth factor (NGF), the ligands of IL-1 receptor-like 1 (IL1RL1) and neurotrophic receptor tyrosine kinase 1 (NTRK1), respectively, enhanced the basophilic differentiation of MYB-GATA1-expressing UT-7 cells, thus demonstrating the importance of this pathway in the basophilic differentiation of leukaemic cells and CD34-positive primary cells. Finally, gene reporter assays confirmed that MYB and MYB-GATA1 directly activated NTRK1 and IL1RL1 transcription, leading to basophilic skewing of the blasts. MYB-GATA1 is more efficient than MYB, because of better stability. Our results highlight the role of IL-33 and NGF receptors in the basophilic differentiation of normal and leukaemic cells. Copyright © 2017 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
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Interleucina-33/fisiología , Leucemia Basofílica Aguda/etiología , Receptores de Factor de Crecimiento Nervioso/fisiología , Animales , Transformación Celular Neoplásica/genética , Femenino , Factor de Transcripción GATA1/genética , Fusión Génica/fisiología , Células Madre Hematopoyéticas/fisiología , Masculino , Ratones SCID , Trasplante de Neoplasias , Proteínas Oncogénicas v-myb/genética , Receptor trkA/metabolismo , Factores de Transcripción/metabolismo , Transfección , Trasplante HeterólogoRESUMEN
Purpose: Genetic and preclinical studies have implicated FGFR signaling in the pathogenesis of adenoid cystic carcinoma (ACC). Dovitinib, a suppressor of FGFR activity, may be active in ACC.Experimental Design: In a two-stage phase II study, 35 patients with progressive ACC were treated with dovitinib 500 mg orally for 5 of 7 days continuously. The primary endpoints were objective response rate and change in tumor growth rate. Progression-free survival, overall survival, metabolic response, biomarker, and quality of life were secondary endpoints.Results: Of 34 evaluable patients, 2 (6%) had a partial response and 22 (65%) had stable disease >4 months. Median PFS was 8.2 months and OS was 20.6 months. The slope of the overall TGR fell from 1.95 to 0.63 on treatment (P < 0.001). Toxicity was moderate; 63% of patients developed grade 3-4 toxicity, 94% required dose modifications, and 21% stopped treatment early. An early metabolic response based on 18FDG-PET scans was seen in 3 of 15 patients but did not correlate with RECIST response. MYB gene translocation was observed and significantly correlated with overexpression of MYB but did not correlate with FGFR1 phosphorylation or clinical response to dovitinib.Conclusions: Dovitinib produced few objective responses in patients with ACC but did suppress the TGR with a PFS that compares favorably with those reported with other targeted agents. Future studies of more potent and selective FGFR inhibitors in biomarker-selected patients will be required to determine whether FGFR signaling is a valid therapeutic target in ACC. Clin Cancer Res; 23(15); 4138-45. ©2017 AACR.
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Bencimidazoles/administración & dosificación , Carcinoma Adenoide Quístico/tratamiento farmacológico , Proliferación Celular/efectos de los fármacos , Recurrencia Local de Neoplasia/tratamiento farmacológico , Quinolonas/administración & dosificación , Adulto , Anciano , Bencimidazoles/efectos adversos , Carcinoma Adenoide Quístico/patología , Supervivencia sin Enfermedad , Femenino , Humanos , Masculino , Persona de Mediana Edad , Metástasis de la Neoplasia , Recurrencia Local de Neoplasia/patología , Proteínas Oncogénicas v-myb/genética , Quinolonas/efectos adversos , Receptor Tipo 1 de Factor de Crecimiento de Fibroblastos/genéticaRESUMEN
Four SNPs (rs7482144, rs4671393, rs28384513 and rs4895441) associated with HbF levels have been identified in different populations worldwide. To explore whether these SNPs modulate HbF expression in Chinese Zhuang population, 436 Chinese Zhuang ß-thalassemia intermedia (ß-TI) patients were divided into high HbF level group (mean HbF=25.5%, n=218) and low group (mean HbF=6.51%, n=218) for genotyping using PCR-HRM method. Results demonstrated that there was a significantly higher minor allele frequency (MAF=34.2%) of rs4895441 (G) in HMIP in high HbF level group than that in low group (MAF=19.8%) (P=0.001, OR=1.73, 95% CI: 1.24-2.57). The cumulative effects of risk genotypes of these loci for patients carrying any combination of 1, 2 or 3 risk genotype had a gradually increased risk of high HbF level phenotype compared to those without the risk genotypes (OR=1.50-9.06, P=0.0008); Gene-gene interaction of rs7842144 and rs4895441 showed the best model with the smallest prediction error (0.4259) and the greatest consistency of coefficient of variation (P=0.01). We concluded that rs4895441, G on HMIP might be a high-risk modifier variant for high HbF level expression, and HBG2, BCL11A and HMIP genes, as HbF quantitative trait loci (QTL) could have a synergistic effect on increasing the HbF level in Chinese Zhuang ß-TI patients.
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Hemoglobina Fetal/análisis , Polimorfismo de Nucleótido Simple , Talasemia beta/sangre , Adolescente , Adulto , Pueblo Asiatico , Proteínas Portadoras/genética , Niño , Preescolar , Femenino , Hemoglobina Fetal/genética , Proteínas de Unión al GTP/genética , Frecuencia de los Genes , Proteínas HSP70 de Choque Térmico/genética , Humanos , Masculino , Proteínas Nucleares/genética , Proteínas Oncogénicas v-myb/genética , Factores de Elongación de Péptidos/genética , Proteínas Represoras , Adulto Joven , Talasemia beta/genéticaRESUMEN
PurposeAdenoid cystic carcinoma (ACC) represents ~10-15% of salivary neoplasms and almost universally exhibits a lethal clinical course. ACC is also known to occur in the lacrimal gland. ACC is characterized by its heterogeneous morphology and may demonstrate tubular, cribriform, and/or solid architectural patterns. Unfortunately, these histopathological features are not specific to ACC and can be seen in other salivary gland-type neoplasms, introducing a diagnostic dilemma. The discovery of fusion transcripts has revolutionized the diagnosis, surveillance, and treatment of epithelial malignancies. In several anatomic subsites ACC is frequently characterized by a fusion transcript involving genes MYB and NFIB; more specifically, t(6;9)(q22-23;p23-24). This study explores the incidence of MYB rearrangement in cases of lacrimal gland ACC using fluorescent in situ hybridization.Materials and methodsRetrospective clinical and histopathological review of 12 cases of lacrimal gland ACC seen at Mayo Clinic over a 25-year period (1990-2015) was performed. Demographic and clinical data were obtained from medical records. Surgical pathology archival material including H&E slides and immunostains was re-examined. Formalin-fixed paraffin-embedded material was further evaluated using immunohistochemistry when appropriate. Fluorescent in situ hybridization (FISH) using a MYB break-apart probe was applied to all histologically confirmed cases of ACC and benign salivary gland parenchyma.ResultsThe median patient age was 53.6 years (range 12-64) and distributed equally by gender (six male and six female). Rearrangement of MYB was identified using FISH in seven cases (58%). Twenty-five sections of benign salivary gland parenchyma showed no evidence of MYB rearrangement. Primary surgical resection was most common treatment, and 78% of the patient received adjuvant radiation therapy. Median overall survival (OS) was 11 years. Rearrangement of MYB did not affect OS.ConclusionsIn summary, our results indicate that the MYB rearrangement defines a significant subset of lacrimal gland ACCs. Importantly, FISH for MYB rearrangement may be used as a diagnostic tool during pathological examination of lacrimal gland neoplasms. Our results showed no relationship between rearrangement status and clinical outcome. Lastly, the presence of t(6;9) in ACC may provide a platform for molecular-targeting strategies in the future.
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Carcinoma Adenoide Quístico/genética , Neoplasias del Ojo/genética , Enfermedades del Aparato Lagrimal/genética , Aparato Lagrimal/patología , Proteínas Oncogénicas v-myb/genética , Adolescente , Adulto , Biomarcadores de Tumor/genética , Biopsia , Carcinoma Adenoide Quístico/diagnóstico , Carcinoma Adenoide Quístico/metabolismo , Niño , Neoplasias del Ojo/diagnóstico , Neoplasias del Ojo/metabolismo , Femenino , Reordenamiento Génico , Humanos , Inmunohistoquímica , Hibridación Fluorescente in Situ , Enfermedades del Aparato Lagrimal/diagnóstico , Enfermedades del Aparato Lagrimal/metabolismo , Masculino , Persona de Mediana Edad , Proteínas Oncogénicas v-myb/metabolismo , Estudios Retrospectivos , Adulto JovenRESUMEN
Adenoid cystic carcinoma is a rare malignant tumor that usually arises in the major and minor salivary glands and other locations containing secretory glands, including the lower female genital tract. Lower female genital tract carcinomas with adenoid cystic differentiation can be subclassified into 2 distinct groups based on the presence or absence of high-risk HPV. Cervical mixed carcinomas with some adenoid cystic differentiation are high-risk HPV-related but pure adenoid cystic carcinomas of vulvar and cervical origin appear to be unrelated to high-risk HPV. Mechanisms by which normal cells give rise to an HPV-unrelated adenoid cystic carcinoma remain largely unknown. Studies demonstrate that chromosomal translocation involving the genes encoding the transcription factors MYB and NFIB functions as a driving force of adenoid cystic carcinomas development regardless of anatomic site. The current study used fluorescence in situ hybridization with 3 different probes including MYB break-apart probe, NFIB break-apart probe, and MYB-NFIB fusion probe to assess for the presence of gene rearrangements in adenoid cystic carcinomas of the vulva. Six (66.7%) of 9 vulvar adenoid cystic carcinomas demonstrated NFIB rearrangement. Of these 6 cases with a disturbed NFIB, only 2 cases (33.3%) were positive for a MYB rearrangement that was also confirmed by a positive MYB-NFIB fusion pattern. NFIB-associated gene rearrangement is a frequent genetic event in vulvar adenoid cystic carcinomas. Chromosome translocations involving NFIB but with an intact MYB indicate the presence of novel oncogenic mechanisms for the development of adenoid cystic carcinomas of the vulva.
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Carcinoma Adenoide Quístico/genética , Reordenamiento Génico , Factores de Transcripción NFI/genética , Proteínas Oncogénicas v-myb/genética , Translocación Genética , Neoplasias de la Vulva/genética , Adulto , Anciano , Anciano de 80 o más Años , Carcinoma Adenoide Quístico/diagnóstico , Carcinoma Adenoide Quístico/patología , Femenino , Humanos , Hibridación Fluorescente in Situ , Persona de Mediana Edad , Vulva/patología , Neoplasias de la Vulva/diagnóstico , Neoplasias de la Vulva/patologíaRESUMEN
Non-transfusion-dependent thalassemia (NTDT) is associated with various forms of thalassemia and genetic modifiers. We report the molecular basis of NTDT in hemoglobin (Hb) E-ß-thalassemia disease. This study was done in 73 adult patients encountered at the prenatal diagnosis center of Khon Kaen University, Northeast Thailand. Hematological parameters and Hb patterns were collected, and α- and ß-globin gene mutations were determined. Multiple single-nucleotide polymorphisms (SNPs) including the rs7482144/Gγ-XmnI polymorphism, rs2297339, rs2838513, rs4895441, and rs9399137 in the HBS1L-MYB gene, rs4671393 and rs11886868 in the BCL11A gene, and G176AfsX179 in the KLF1 gene were examined. Five ß0-thalassemia mutations and a severe ß+-thalassemia mutation in trans to the ßE gene were identified. No significant difference in hematological parameters was observed among ß-thalassemia genotypes. Coinheritance of α-thalassemia was observed in 31 of the 73 subjects (42.5%). Four SNPs including Gγ-XmnI, rs2297339, rs4895441, and rs9399137 of HBS1L-MYB were found to be associated with high Hb F levels in 39 (53.4%) subjects. The molecular basis of NTDT in the remaining 3 (4.1%) cases could not be defined. These results indicate multiple genetic factors in NTDT patients and underline the importance of complete genotyping to provide proper management, make clinical predictions, and improve genetic counseling.
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Genotipo , Hemoglobina E , Mutación , Polimorfismo de Nucleótido Simple , Talasemia beta/genética , Proteínas Portadoras/genética , Femenino , Humanos , Factores de Transcripción de Tipo Kruppel/genética , Masculino , Proteínas Nucleares/genética , Proteínas Oncogénicas v-myb/genética , Proteínas Represoras , Tailandia/epidemiología , Globinas alfa/genética , Globinas beta/genética , Talasemia beta/epidemiologíaRESUMEN
Extensive desmoplasia is a prominent pathological characteristic of pancreatic cancer (PC) that not only impacts tumor development, but therapeutic outcome as well. Recently, we demonstrated a novel role of MYB, an oncogenic transcription factor, in PC growth and metastasis. Here we studied its effect on pancreatic tumor histopathology and associated molecular and biological mechanisms. Tumor-xenografts derived from orthotopic-inoculation of MYB-overexpressing PC cells exhibited far-greater desmoplasia in histological analyses compared with those derived from MYB-silenced PC cells. These findings were further confirmed by immunostaining of tumor-xenograft sections with collagen-I, fibronectin (major extracellular-matrix proteins), and α-SMA (well-characterized marker of myofibroblasts or activated pancreatic stellate cells (PSCs)). Likewise, MYB-overexpressing PC cells provided significantly greater growth benefit to PSCs in a co-culture system as compared with the MYB-silenced cells. Interrogation of deep-sequencing data from MYB-overexpressing versus -silenced PC cells identified Sonic-hedgehog (SHH) and Adrenomedullin (ADM) as two differentially-expressed genes among others, which encode for secretory ligands involved in tumor-stromal cross-talk. In-silico analyses predicted putative MYB-binding sites in SHH and ADM promoters, which was later confirmed by chromatin-immunoprecipitation. A cooperative role of SHH and ADM in growth promotion of PSCs was confirmed in co-culture by using their specific-inhibitors and exogenous recombinant-proteins. Importantly, while SHH acted exclusively in a paracrine fashion on PSCs and influenced the growth of PC cells only indirectly, ADM could directly impact the growth of both PC cells and PSCs. In summary, we identified MYB as novel regulator of pancreatic tumor desmoplasia, which is suggestive of its diverse roles in PC pathobiology.
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Adrenomedulina/biosíntesis , Regulación Neoplásica de la Expresión Génica , Proteínas Hedgehog/biosíntesis , Proteínas Oncogénicas v-myb/metabolismo , Neoplasias Pancreáticas/metabolismo , Comunicación Paracrina , Elementos de Respuesta , Transcripción Genética , Regulación hacia Arriba , Adrenomedulina/genética , Animales , Línea Celular Tumoral , Proteínas Hedgehog/genética , Xenoinjertos , Humanos , Ratones , Trasplante de Neoplasias , Proteínas Oncogénicas v-myb/genética , Neoplasias Pancreáticas/genética , Neoplasias Pancreáticas/patología , Células Estrelladas Pancreáticas/metabolismo , Células Estrelladas Pancreáticas/patologíaRESUMEN
Translocation events are frequent in cancer and may create chimeric fusions or 'regulatory rearrangements' that drive oncogene overexpression. Here we identify super-enhancer translocations that drive overexpression of the oncogenic transcription factor MYB as a recurrent theme in adenoid cystic carcinoma (ACC). Whole-genome sequencing data and chromatin maps highlight distinct chromosomal rearrangements that juxtapose super-enhancers to the MYB locus. Chromosome conformation capture confirms that the translocated enhancers interact with the MYB promoter. Remarkably, MYB protein binds to the translocated enhancers, creating a positive feedback loop that sustains its expression. MYB also binds enhancers that drive different regulatory programs in alternate cell lineages in ACC, cooperating with TP63 in myoepithelial cells and a Notch program in luminal epithelial cells. Bromodomain inhibitors slow tumor growth in ACC primagraft models in vivo. Thus, our study identifies super-enhancer translocations that drive MYB expression and provides insight into downstream MYB functions in alternate ACC lineages.
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Carcinoma Adenoide Quístico/genética , Elementos de Facilitación Genéticos , Proteínas Oncogénicas v-myb/biosíntesis , Translocación Genética , Carcinoma Adenoide Quístico/patología , Línea Celular Tumoral , Linaje de la Célula/genética , Cromatina/genética , Regulación Neoplásica de la Expresión Génica , Humanos , Proteínas Oncogénicas v-myb/genética , Proteínas de Fusión Oncogénica/biosíntesis , Proteínas de Fusión Oncogénica/genética , Factores de Transcripción/biosíntesis , Proteínas Supresoras de Tumor/biosíntesisRESUMEN
Angiocentric gliomas are pediatric low-grade gliomas (PLGGs) without known recurrent genetic drivers. We performed genomic analysis of new and published data from 249 PLGGs, including 19 angiocentric gliomas. We identified MYB-QKI fusions as a specific and single candidate driver event in angiocentric gliomas. In vitro and in vivo functional studies show that MYB-QKI rearrangements promote tumorigenesis through three mechanisms: MYB activation by truncation, enhancer translocation driving aberrant MYB-QKI expression and hemizygous loss of the tumor suppressor QKI. To our knowledge, this represents the first example of a single driver rearrangement simultaneously transforming cells via three genetic and epigenetic mechanisms in a tumor.
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Glioma/genética , Proteínas Oncogénicas v-myb/genética , Proteínas de Fusión Oncogénica/genética , Proteínas de Unión al ARN/genética , Carcinogénesis/genética , Línea Celular Tumoral , Niño , Hibridación Genómica Comparativa , Exoma/genética , Regulación Neoplásica de la Expresión Génica , Reordenamiento Génico , Glioma/patología , Secuenciación de Nucleótidos de Alto Rendimiento , Humanos , Mutación , Proteínas Oncogénicas v-myb/biosíntesis , Proteínas de Fusión Oncogénica/biosíntesis , Proteínas de Unión al ARN/biosíntesisRESUMEN
Despite stringent procedures to secure the best HLA matching between donors and recipients, life-threatening complications continue to occur after hematopoietic stem cell transplantation (HSCT). Studying single nucleotide polymorphism (SNP) in genes encoding costimulatory molecules could help identify patients at risk for post-HSCT complications. In a stepwise approach we selected SNPs in key costimulatory molecules including CD274, CD40, CD154, CD28, and TNFSF4 and systematically analyzed their association with post-HSCT outcomes. Our discovery cohort analysis of 1157 HLA-A, -B, -C, -DRB1, and -DQB1 matched cases found that patients with donors homozygous for the C variant of rs10912564 in TNFSF4 (48%) had better disease-free survival (P = .029) and overall survival (P = .009) with less treatment-related mortality (P = .006). Our data demonstrate the TNFSF4C variant had a higher affinity for the nuclear transcription factor Myb and increased percentage of TNFSF4-positive B cells after stimulation compared with CT or TT genotypes. However, these associations were not validated in a more recent cohort, potentially because of changes in standard of practice or absence of a true association. Given the discovery cohort, functional data, and importance of TNFSF4 in infection clearance, TNFSF4C may associate with outcomes and warrants future studies.
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Neoplasias Hematológicas/genética , Trasplante de Células Madre Hematopoyéticas , Homocigoto , Ligando OX40/genética , Adolescente , Adulto , Anciano , Antígenos CD , Linfocitos B , Estudios de Casos y Controles , Niño , Preescolar , Supervivencia sin Enfermedad , Femenino , Antígenos HLA/genética , Neoplasias Hematológicas/mortalidad , Neoplasias Hematológicas/patología , Neoplasias Hematológicas/terapia , Humanos , Lactante , Masculino , Persona de Mediana Edad , Proteínas Oncogénicas v-myb/genética , Polimorfismo de Nucleótido Simple , Tasa de SupervivenciaRESUMEN
The MYB transcription factor plays critical roles in normal and malignant haematopoiesis. We previously showed that MYB was a direct activator of FLT3 expression within the context of acute myeloid leukaemia. During normal haematopoiesis, increasing levels of FLT3 expression determine a strict hierarchy within the haematopoietic stem and early progenitor compartment, which associates with lymphoid and myeloid commitment potential. We use the conditional deletion of the Myb gene to investigate the influence of MYB in Flt3 transcriptional regulation within the haematopoietic stem cell (HSC) hierarchy. In accordance with previous report, in vivo deletion of Myb resulted in rapid biased differentiation of HSC with concomitant loss of proliferation capacity. We find that loss of MYB activity also coincided with decreased FLT3 expression. At the chromatin level, the Flt3 promoter is primed in immature HSC, but occupancy of further intronic elements determines expression. Binding to these locations, MYB and C/EBPα need functional cooperation to activate transcription of the locus. This cooperation is cell context dependent and indicates that MYB and C/EBPα activities are inter-dependent in controlling Flt3 expression to influence lineage commitment of multipotential progenitors.
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Proteínas Potenciadoras de Unión a CCAAT/fisiología , Células Madre Hematopoyéticas/metabolismo , Proteínas Oncogénicas v-myb/fisiología , Tirosina Quinasa 3 Similar a fms/genética , Animales , Proteínas Potenciadoras de Unión a CCAAT/genética , Diferenciación Celular/genética , Linaje de la Célula/genética , Células Cultivadas , Regulación de la Expresión Génica , Hematopoyesis/genética , Ratones , Ratones Endogámicos C57BL , Ratones Transgénicos , Proteínas Oncogénicas v-myb/genética , Tirosina Quinasa 3 Similar a fms/metabolismoRESUMEN
UNLABELLED: Cyclin E1 is essential for the reentry of quiescent cells into the cell cycle. When hypomorphic mutant Myb mice (Myb(Plt4)) were examined, it was noted that Cyclin E1 (Ccne1) expression was reduced. Furthermore, the induction of Ccne1 in recovering intestinal epithelia following radiation-induced damage was ablated in Myb-mutant mice. These data prompted us to investigate whether Myb directly regulated Ccne1 and to examine whether elevated Myb in colorectal cancer is responsible for Cyclin E1-driven tumor growth. Here, it was found that Myb/MYB and Ccne1/CCNE1 expressions were coupled in both mouse and human adenomas. In addition, the low molecular weight Cyclin E1 was the predominant form in intestinal crypts and adenomatous polyposis coli (Apc)-mutant adenomas. Chromatin immunoprecipitation (ChIP) analysis confirmed that Myb bound directly to the Ccne1 promoter and regulated its endogenous expression. In contrast, Myb(Plt4) served as a dominant-negative factor that inhibited wild-type Myb and this was not apparently compensated for by the transcription factor E2F1 in intestinal epithelial cells. Myb(Plt4/Plt4) mice died prematurely on an Apc(Min/) (+) background associated with hematopoietic defects, including a myelodysplasia; nevertheless, Apc(Min/) (+) mice were protected from intestinal tumorigenesis when crossed to Myb(Plt4/) (+) mice. Knockdown of CCNE1 transcript in murine colorectal cancer cells stabilized chromosome ploidy and decreased tumor formation. These data suggest that Cyclin E1 expression is Myb dependent in normal and transformed intestinal epithelial cells, consistent with a cell-cycle progression and chromosome instability role in cancer. IMPLICATIONS: This study demonstrates that Myb regulates Cyclin E1 expression in normal gastrointestinal tract epithelial cells and is required during intestinal tumorigenesis.
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Carcinogénesis/metabolismo , Neoplasias Colorrectales/metabolismo , Ciclina E/metabolismo , Regulación Neoplásica de la Expresión Génica , Proteínas Oncogénicas v-myb/genética , Proteínas Oncogénicas/metabolismo , Adenoma/metabolismo , Animales , Ciclo Celular , Línea Celular Tumoral , Proliferación Celular , Inmunoprecipitación de Cromatina , Inestabilidad Cromosómica , Cromosomas/ultraestructura , Progresión de la Enfermedad , Femenino , Hematopoyesis , Humanos , Inmunoprecipitación , Mucosa Intestinal/metabolismo , Neoplasias Intestinales/metabolismo , Masculino , Ratones , Ratones Endogámicos C57BL , Mutación , Ploidias , Regiones Promotoras GenéticasRESUMEN
BACKGROUND: The transcription factor NK2 homeobox 1 (Nkx2-1) plays essential roles in epithelial cell proliferation and differentiation in mouse and human lung development and tumorigenesis. A better understanding of genes and pathways downstream of Nkx2-1 will clarify the multiple roles of this critical lung factor. Nkx2-1 regulates directly or indirectly numerous protein-coding genes; however, there is a paucity of information about Nkx2-1-regulated microRNAs (miRNAs). METHODS AND RESULTS: By miRNA array analyses of mouse epithelial cell lines in which endogenous Nkx2-1 was knocked-down, we revealed that 29 miRNAs were negatively regulated including miR-200c, and 39 miRNAs were positively regulated by Nkx2-1 including miR-1195. Mouse lungs lacking functional phosphorylated Nkx2-1 showed increased expression of miR-200c and alterations in the expression of other top regulated miRNAs. Moreover, chromatin immunoprecipitation assays showed binding of NKX2-1 protein to regulatory regions of these miRNAs. Promoter reporter assays indicated that 1kb of the miR-200c 5' flanking region was transcriptionally active but did not mediate Nkx2-1- repression of miR-200c expression. 3'UTR reporter assays support a direct regulation of the predicted targets Nfib and Myb by miR-200c. CONCLUSIONS: These studies suggest that Nkx2-1 controls the expression of specific miRNAs in lung epithelial cells. In particular, we identified a regulatory link between Nkx2-1, the known tumor suppressor miR-200c, and the developmental and oncogenic transcription factors Nfib and Myb, adding new players to the regulatory mechanisms driven by Nkx2-1 in lung epithelial cells that may have implications in lung development and tumorigenesis.