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1.
Proc Natl Acad Sci U S A ; 115(41): 10357-10362, 2018 10 09.
Artículo en Inglés | MEDLINE | ID: mdl-30257940

RESUMEN

PAX5 is a well-known haploinsufficient tumor suppressor gene in human B-cell precursor acute lymphoblastic leukemia (B-ALL) and is involved in various chromosomal translocations that fuse a part of PAX5 with other partners. However, the role of PAX5 fusion proteins in B-ALL initiation and transformation is ill-known. We previously reported a new recurrent t(7;9)(q11;p13) chromosomal translocation in human B-ALL that juxtaposed PAX5 to the coding sequence of elastin (ELN). To study the function of the resulting PAX5-ELN fusion protein in B-ALL development, we generated a knockin mouse model in which the PAX5-ELN transgene is expressed specifically in B cells. PAX5-ELN-expressing mice efficiently developed B-ALL with an incidence of 80%. Leukemic transformation was associated with recurrent secondary mutations on Ptpn11, Kras, Pax5, and Jak3 genes affecting key signaling pathways required for cell proliferation. Our functional studies demonstrate that PAX5-ELN affected B-cell development in vitro and in vivo featuring an aberrant expansion of the pro-B cell compartment at the preleukemic stage. Finally, our molecular and computational approaches identified PAX5-ELN-regulated gene candidates that establish the molecular bases of the preleukemic state to drive B-ALL initiation. Hence, our study provides a new in vivo model of human B-ALL and strongly implicates PAX5 fusion proteins as potent oncoproteins in leukemia development.


Asunto(s)
Elastina/genética , Proteínas de Fusión Oncogénica/genética , Factor de Transcripción PAX5/genética , Leucemia-Linfoma Linfoblástico de Células Precursoras/genética , Leucemia-Linfoma Linfoblástico de Células Precursoras/patología , Animales , Linfocitos B/patología , Linfocitos B/fisiología , Elastina/metabolismo , Regulación Leucémica de la Expresión Génica , Técnicas de Sustitución del Gen , Janus Quinasa 3/genética , Ratones Transgénicos , Mutación , Neoplasias Experimentales , Proteínas de Fusión Oncogénica/metabolismo , Factor de Transcripción PAX5/metabolismo , Proteína Tirosina Fosfatasa no Receptora Tipo 11/genética , Proteínas Proto-Oncogénicas p21(ras)/genética
2.
Haematologica ; 102(10): 1718-1726, 2017 10.
Artículo en Inglés | MEDLINE | ID: mdl-28679652

RESUMEN

Long non-coding RNAs are defined as transcripts larger than 200 nucleotides but without protein-coding potential. There is growing evidence of the important role of long non-coding RNAs in cancer initiation, development and progression. In this study, we sought to evaluate the long non-coding RNA expression profile of patients with cytogenetically normal acute myeloid leukemia (AML). RNA-sequencing of 40 cytogenetically normal AML patients allowed us to quantify 11,036 long non-coding RNAs. Among these, more than 8000 were previously undescribed long non-coding RNAs. Using unsupervised analysis, we observed a specific long non-coding RNA expression profile dependent on the mutational status of the NPM1 gene. Statistical analysis allowed us to identify a minimal set of 12 long non-coding RNAs capable of discriminating NPM1-mutated from NPM1-wild-type patients. These results were validated by qRT-PCR on an independent cohort composed of 134 cytogenetically normal AML patients. Furthermore, we have identified one putative biomarker, the long non-coding RNA XLOC_109948 whose expression pattern predicts clinical outcome. Interestingly, low XLOC_109948 expression indicates a good prognosis especially for NPM1-mutated patients. Transient transfection of GapmeR against XLOC_109948 in NPM1-mutated OCI-AML3 cell line treated with Ara-C or ATRA enhances apoptosis suggesting XLOC_109948 plays a role in drug sensitivity. This study improves our knowledge of the long non-coding RNA transcriptome in cytogenetically normal AML patients. We observed a distinct long non-coding RNA expression profile in patients with the NPM1 mutation. The newly identified XLOC_109948 long non-coding RNA emerged as a strong prognostic factor able to better stratify NPM1-mutated patients.


Asunto(s)
Leucemia Mieloide Aguda/diagnóstico , Leucemia Mieloide Aguda/genética , Mutación , Proteínas Nucleares/genética , ARN Largo no Codificante/genética , Transcriptoma , Apoptosis/genética , Biomarcadores , Línea Celular Tumoral , Análisis por Conglomerados , Perfilación de la Expresión Génica , Regulación Leucémica de la Expresión Génica , Humanos , Cariotipo , Leucemia Mieloide Aguda/mortalidad , Nucleofosmina , Pronóstico , Análisis de Secuencia de ARN
3.
Leukemia ; 38(8): 1764-1776, 2024 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-38909090

RESUMEN

Malignant growth relies on rapid protein synthesis frequently leading to endoplasmic reticulum (ER) overload and accumulation of unfolded or misfolded protein in this cellular compartment. In the ER, protein homeostasis is finely regulated by a mechanism called the unfolded protein response (UPR), involving the activation of signalization pathways mediated by three transmembrane proteins, namely PERK, IRE1 and ATF6. IRE1 endoribonuclease activation leads in particular to the splicing of the cytosolic mRNA encoding the key UPR-specific transcription factor XBP1s. Our study shows that sustained activation of XBP1s expression in acute myeloid leukemia (AML) cells induces apoptosis in vitro and in vivo, whereas a moderate XBP1s expression sensitizes cells to chemotherapeutic treatments. ChIP-seq experiments identified specific XBP1s target genes including the MIR22HG lncRNA, the precursor transcript of microRNA-22-3p. miR-22-3p upregulation by XBP1s or forced expression of miR-22 significantly decreases cell's viability and sensitizes leukemic cells to chemotherapy. We found that miR-22-3p intracellular effects result at least partially from the targeting of the mRNA encoding the deacetylase sirtuin-1 (SIRT1), a well-established pro-survival factor. Therefore, this novel XBP1s/miR-22/SIRT1 axis identified could play a pivotal role in the proliferation and chemotherapeutic response of leukemic cells.


Asunto(s)
Apoptosis , Estrés del Retículo Endoplásmico , Leucemia Mieloide Aguda , MicroARNs , Sirtuina 1 , Proteína 1 de Unión a la X-Box , Humanos , MicroARNs/genética , Proteína 1 de Unión a la X-Box/metabolismo , Proteína 1 de Unión a la X-Box/genética , Leucemia Mieloide Aguda/tratamiento farmacológico , Leucemia Mieloide Aguda/genética , Leucemia Mieloide Aguda/patología , Leucemia Mieloide Aguda/metabolismo , Estrés del Retículo Endoplásmico/efectos de los fármacos , Sirtuina 1/metabolismo , Sirtuina 1/genética , Animales , Ratones , Respuesta de Proteína Desplegada/efectos de los fármacos , Línea Celular Tumoral , Transducción de Señal , Proliferación Celular
4.
Sci Rep ; 14(1): 7070, 2024 03 25.
Artículo en Inglés | MEDLINE | ID: mdl-38528080

RESUMEN

The PI3K-AKT-mTOR pathway lies at the confluence of signaling pathways in which various components are subjected to activating genetic alterations in acute myeloid leukemia (AML), thus contributing to oncogenesis. Three AKT isoforms exist in humans. However, whether one isoform predominates in AML remains unknown. This study reveals that AKT3 behaves very distinctly than AKT1 or AKT2 in both normal myeloid differentiation and AML. During normal differentiation, AKT3 is preferentially expressed in hematopoietic stem cells whilst AKT1 becomes preferentially expressed as cells differentiate into granulocytes or monocytes. AKT2 expression remains unchanged. In AML, AKT3 expression varies widely among patient samples and is counterintuitively high in mature/monocytic leukemia. Furthermore, a low level of AKT3 expression is strongly correlated to genetic alterations associated with a better outcome (NPM1 mutations and RUNX1-RUNX1T1 translocation), while a high level is correlated to alterations associated to a bad outcome (RUNX1 mutations; and SRSF2, U2AF1, SF3B1, ASXL1 and BCOR mutations occurring frequently in MDS and MPN). Consistently, a high AKT3 expression level appears as a very strong predictor of poor survival. Curiously, although modestly varying among AML samples, a high AKT1 expression shows in contrast as a strong predictor of a better patient outcome. These data suggest that AKT3 and AKT1 expressions have strong, yet opposite, prognostic values.


Asunto(s)
Leucemia Mieloide Aguda , Proteínas Proto-Oncogénicas c-akt , Humanos , Subunidad alfa 2 del Factor de Unión al Sitio Principal/genética , Leucemia Mieloide Aguda/genética , Mutación , Fosfatidilinositol 3-Quinasas/genética , Pronóstico , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , Proteínas Proto-Oncogénicas c-akt/genética , Proteínas Proto-Oncogénicas c-akt/metabolismo
5.
Proc Natl Acad Sci U S A ; 107(50): 21558-63, 2010 Dec 14.
Artículo en Inglés | MEDLINE | ID: mdl-21118985

RESUMEN

MicroRNA miR-125b has been implicated in several kinds of leukemia. The chromosomal translocation t(2;11)(p21;q23) found in patients with myelodysplasia and acute myeloid leukemia leads to an overexpression of miR-125b of up to 90-fold normal. Moreover, miR-125b is also up-regulated in patients with B-cell acute lymphoblastic leukemia carrying the t(11;14)(q24;q32) translocation. To decipher the presumed oncogenic mechanism of miR-125b, we used transplantation experiments in mice. All mice transplanted with fetal liver cells ectopically expressing miR-125b showed an increase in white blood cell count, in particular in neutrophils and monocytes, associated with a macrocytic anemia. Among these mice, half died of B-cell acute lymphoblastic leukemia, T-cell acute lymphoblastic leukemia, or a myeloproliferative neoplasm, suggesting an important role for miR-125b in early hematopoiesis. Furthermore, coexpression of miR-125b and the BCR-ABL fusion gene in transplanted cells accelerated the development of leukemia in mice, compared with control mice expressing only BCR-ABL, suggesting that miR-125b confers a proliferative advantage to the leukemic cells. Thus, we show that overexpression of miR-125b is sufficient both to shorten the latency of BCR-ABL-induced leukemia and to independently induce leukemia in a mouse model.


Asunto(s)
Leucemia/etiología , Leucemia/genética , MicroARNs/genética , Oncogenes , Animales , Transformación Celular Neoplásica , Proteínas de Fusión bcr-abl/genética , Proteínas de Fusión bcr-abl/metabolismo , Regulación Leucémica de la Expresión Génica , Humanos , Hígado/citología , Masculino , Ratones , Ratones Endogámicos BALB C , Ratones Endogámicos C57BL , Trasplante de Neoplasias
6.
Blood ; 115(15): 3089-97, 2010 Apr 15.
Artículo en Inglés | MEDLINE | ID: mdl-20160164

RESUMEN

PAX5 is the main target of somatic mutations in acute B lymphoblastic leukemia (B-ALL). We analyzed 153 adult and child B-ALL harboring karyotypic abnormalities at chromosome 9p, to determine the frequency and the nature of PAX5 alterations. We found PAX5 internal rearrangements in 21% of the cases. To isolate fusion partners, we used classic and innovative techniques (rolling circle amplification-rapid amplification of cDNA ends) and single nucleotide polymorphism-comparative genomic hybridization arrays. Recurrent and novel fusion partners were identified, including NCoR1, DACH2, GOLGA6, and TAOK1 genes showing the high variability of the partners. We noted that half the fusion genes can give rise to truncated PAX5 proteins. Furthermore, malignant cells carrying PAX5 fusion genes displayed a simple karyotype. These data strongly suggest that PAX5 fusion genes are early players in leukemogenesis. In addition, PAX5 deletion was observed in 60% of B-ALL with 9p alterations. Contrary to cases with PAX5 fusions, deletions were associated with complex karyotypes and common recurrent translocations. This supports the hypothesis of the secondary nature of the deletion. Our data shed more light on the high variability of PAX5 alterations in B-ALL. Therefore, it is probable that gene fusions occur early, whereas deletions should be regarded as a late/secondary event.


Asunto(s)
Análisis Citogenético , Mutación/genética , Factor de Transcripción PAX5/genética , Leucemia-Linfoma Linfoblástico de Células Precursoras B/genética , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Puntos de Rotura del Cromosoma , Cromosomas Humanos Par 9/genética , Clonación Molecular , Estudios de Cohortes , Femenino , Francia , Regulación Leucémica de la Expresión Génica , Humanos , Cariotipificación , Masculino , Persona de Mediana Edad , Proteínas de Fusión Oncogénica/genética , Proteínas de Fusión Oncogénica/metabolismo , Leucemia-Linfoma Linfoblástico de Células Precursoras B/patología , Adulto Joven
7.
Haematologica ; 97(11): 1713-21, 2012 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-22689670

RESUMEN

BACKGROUND: We previously described a t(2;11)(p21;q23) chromosomal translocation found in patients with myelodysplasia or acute myeloid leukemia that leads to over-expression of the microRNA miR-125b, and we showed that transplantation of mice with murine stem/progenitor cells overexpressing miR-125b is able to induce leukemia. In this study, we investigated the mechanism of myeloid transformation by miR-125b. DESIGN AND METHODS: To investigate the consequences of miR-125b over-expression on myeloid differentiation, apoptosis and proliferation, we used the NB4 and HL60 human promyelocytic cell lines and the 32Dclone3 murine promyelocytic cell line. To test whether miR-125b is able to transform myeloid cells, we used the non-tumorigenic and interleukin-3-dependent 32Dclone3 cell line over-expressing miR-125b, in xenograft experiments in nude mice and in conditions of interleukin-3 deprivation. To identify new miR-125b targets, we compared, by RNA-sequencing, the transcriptome of cell lines that do or do not over-express miR-125b. RESULTS: We showed that miR-125b over-expression blocks apoptosis and myeloid differentiation and enhances proliferation in both species. More importantly, we demonstrated that miR-125b is able to transform the 32Dclone3 cell line by conferring growth independence from interleukin-3; xenograft experiments showed that these cells form tumors in nude mice. Using RNA-sequencing and quantitative real-time polymerase chain reaction experiments, we identified multiple miR-125b targets. We demonstrated that ABTB1, an anti-proliferative factor, is a new direct target of miR-125b and we confirmed that CBFB, a transcription factor involved in hematopoiesis, is also targeted by miR-125b. MiR-125b controls apoptosis by down-regulating genes involved in the p53 pathway including BAK1 and TP53INP1. CONCLUSIONS: This study demonstrates that in a myeloid context, miR-125b is an oncomiR able to transform cell lines. miR-125b blocks myeloid differentiation in part by targeting CBFB, blocks apoptosis through down-regulation of multiple genes involved in the p53 pathway, and confers a proliferative advantage to human and mouse myeloid cell lines in part by targeting ABTB1.


Asunto(s)
Transformación Celular Neoplásica/metabolismo , Leucemia Promielocítica Aguda/metabolismo , MicroARNs/metabolismo , Células Mieloides/metabolismo , Células Madre Neoplásicas/metabolismo , ARN Neoplásico/metabolismo , Animales , Apoptosis/genética , Diferenciación Celular/genética , Transformación Celular Neoplásica/genética , Transformación Celular Neoplásica/patología , Células HL-60 , Humanos , Leucemia Promielocítica Aguda/genética , Leucemia Promielocítica Aguda/patología , Ratones , Ratones Desnudos , MicroARNs/genética , Síndromes Mielodisplásicos/genética , Síndromes Mielodisplásicos/metabolismo , Síndromes Mielodisplásicos/patología , Células Mieloides/patología , Proteínas de Neoplasias/genética , Proteínas de Neoplasias/metabolismo , Células Madre Neoplásicas/patología , ARN Neoplásico/genética , Trasplante de Células Madre , Trasplante Heterólogo
10.
Leukemia ; 35(10): 2784-2798, 2021 10.
Artículo en Inglés | MEDLINE | ID: mdl-34131282

RESUMEN

The most frequent genetic alteration in acute myeloid leukemia (AML) is the mutation of nucleophosmin 1 (NPM1). Yet, its downstream oncogenic routes are not fully understood. Here, we report the identification of one long noncoding RNA (lncRNA) overexpressed in NPM1-mutated AML patients (named LONA) whose intracellular localization inversely reflects that of NPM1. While NPM1 is nuclear and LONA cytoplasmic in wild-type NPM1 AML cells, LONA becomes nuclear as mutant NPM1 moves toward the cytoplasm. Gain or loss of function combined with a genome-wide RNA-seq search identified a set of LONA mRNA targets encoding proteins involved in myeloid cell differentiation (including THSB1, MAFB, and ASB2) and interaction with its microenvironment. Consistently, LONA overexpression in mutant NPM1 established cell lines and primary AML cells exerts an anti-myeloid differentiation effect, whilst it exerts an opposite pro-myeloid differentiation effect in a wild type NPM1 setting. In vivo, LONA overexpression acts as an oncogenic lncRNA reducing the survival of mice transplanted with AML cells and rendering AML tumors more resistant to AraC chemotherapy.These data indicate that mutation-dependent nuclear export of NPM1 leads to nuclear retention and consequent oncogenic functions of the overexpressed lncRNA LONA, thus uncovering a novel NPM1 mutation-dependent pathway in AML pathogenesis.


Asunto(s)
Transporte Activo de Núcleo Celular/genética , Núcleo Celular/genética , Leucemia Mieloide Aguda/genética , Mutación/genética , Proteínas Nucleares/genética , ARN Largo no Codificante/genética , Animales , Carcinogénesis/genética , Diferenciación Celular/genética , Línea Celular Tumoral , Citoplasma/genética , Regulación Leucémica de la Expresión Génica/genética , Células HL-60 , Humanos , Masculino , Ratones , Ratones Endogámicos NOD , Ratones SCID , Nucleofosmina , ARN Mensajero/genética , Microambiente Tumoral/genética
12.
Cancers (Basel) ; 11(11)2019 Oct 24.
Artículo en Inglés | MEDLINE | ID: mdl-31653018

RESUMEN

Acute Myeloid Leukemia (AML) is the most common form of leukemia in adults with an incidence of 4.3 per 100,000 cases per year. Historically, the identification of genetic alterations in AML focused on protein-coding genes to provide biomarkers and to understand the molecular complexity of AML. Despite these findings and because of the heterogeneity of this disease, questions as to the molecular mechanisms underlying AML development and progression remained unsolved. Recently, transcriptome-wide profiling approaches have uncovered a large family of long noncoding RNAs (lncRNAs). Larger than 200 nucleotides and with no apparent protein coding potential, lncRNAs could unveil a new set of players in AML development. Originally considered as dark matter, lncRNAs have critical roles to play in the different steps of gene expression and thus affect cellular homeostasis including proliferation, survival, differentiation, migration or genomic stability. Consequently, lncRNAs are found to be differentially expressed in tumors, notably in AML, and linked to the transformation of healthy cells into leukemic cells. In this review, we aim to summarize the knowledge concerning lncRNAs functions and implications in AML, with a particular emphasis on their prognostic and therapeutic potential.

13.
Am J Clin Pathol ; 129(5): 723-6, 2008 May.
Artículo en Inglés | MEDLINE | ID: mdl-18426731

RESUMEN

We selected a series of 63 primary diffuse large B-cell lymphomas (DLBCLs) of bone collected in tissue microarrays from centers in France and Brazil. These cases were classified according to the expression of antigens associated with germinal center (GC; n = 42) or non-GC (n = 21) stages of B-cell differentiation. By fluorescence in situ hybridization, we found a substantial number of cases with a rearrangement of BCL2 (9/32) and c -MYC (n = 3), whereas the PAX5, BCL6, BCL1 cyclin D1, and ALK genes were in germline configuration. It is interesting that 1 case, with a GC phenotype, showed dual BCL2 and c -MYC rearrangement. The majority of the cases with rearrangements were of the GC phenotype. These results, associated with the lack of BCL6 rearrangement, suggest that bone DLBCL represents a specific group within extranodal B-cell lymphomas.


Asunto(s)
Neoplasias Óseas/genética , Genes bcl-2/genética , Genes myc/genética , Linfoma de Células B Grandes Difuso/genética , Neoplasias Óseas/patología , Centro Germinal/patología , Humanos , Inmunohistoquímica , Hibridación Fluorescente in Situ , Linfoma de Células B Grandes Difuso/patología , Análisis de Matrices Tisulares
14.
J Clin Pathol ; 60(5): 573-5, 2007 May.
Artículo en Inglés | MEDLINE | ID: mdl-17513519

RESUMEN

Follicular lymphoma (FL) is a neoplasm originating from germinal centre cells, corresponding to 25-40% of non-Hodgkin's lymphomas. Transformation into diffuse large B cell lymphoma (DLBCL) occurs in about one-third of cases. CD5 is expressed in B-chronic lymphoid leukaemia/small lymphocytic lymphoma and mantle cell lymphoma, but can rarely be expressed in conjunction with CD10 in well-documented cases of FL. In this report one case of grade 1 FL is described, which transformed into a DLBCL 6 months after initial diagnosis, with both tumours expressing CD5. In both specimens, neoplastic cells were strongly positive for CD20, CD79a, bcl-2, bcl-6 and CD5 in virtually all cells. CD10 was strongly positive in initial specimens and weakly positive in the DLBCL. Investigation using the PCR confirmed the derivation of the DLBCL from the FL as they presented the same immunoglobulin heavy chain gene rearrangement and the same BCL2-J(H) break point.


Asunto(s)
Antígenos CD5/metabolismo , Linfoma de Células B/patología , Linfoma Folicular/patología , Linfoma de Células B Grandes Difuso/patología , Adulto , Antígenos de Neoplasias/metabolismo , Progresión de la Enfermedad , Femenino , Humanos , Linfoma de Células B/inmunología , Linfoma Folicular/inmunología , Linfoma de Células B Grandes Difuso/inmunología
15.
Oncogene ; 24(48): 7248-52, 2005 Nov 03.
Artículo en Inglés | MEDLINE | ID: mdl-16091753

RESUMEN

Several tyrosine kinase genes are involved in chromosomal translocations in chronic myeloproliferative disorders, but there are still uncharacterized translocations in some cases. We report two such cases corresponding to atypical chronic myeloid leukaemia with a t(8;9)(p22;p24) translocation. By fluorescence in situ hybridisation (FISH) on the corresponding metaphases with a bacterial artificial chromosome probe encompassing the janus kinase 2 (JAK2) gene at 9p24, we observed a split for both patients, suggesting that this gene was rearranged. The locus at 8p22 contains different candidate genes including the pericentriolar material 1 gene (PCM1), already implicated in reciprocal translocations. The rearrangement of the PCM1 gene was demonstrated by FISH, for both patients. By RT-PCR, we confirmed the fusion of 3' part of JAK2 with the 5' part of PCM1. Sequence analysis of the chimeric PCM1-JAK2 mRNA suggests that the putative protein displays the coiled-coil domains of PCM1 and the tyrosine kinase domain of JAK2. This new translocation identifies JAK2 as a possible therapeutic target for compounds with anti-tyrosine kinase activity.


Asunto(s)
Proteínas de Ciclo Celular/genética , Cromosomas Humanos Par 8 , Cromosomas Humanos Par 9 , Leucemia Mielógena Crónica BCR-ABL Positiva/genética , Proteínas de Fusión Oncogénica/genética , Proteínas Tirosina Quinasas/genética , Proteínas Proto-Oncogénicas/genética , Translocación Genética , Antibióticos Antineoplásicos/uso terapéutico , Antimetabolitos Antineoplásicos/uso terapéutico , Antineoplásicos/uso terapéutico , Autoantígenos , Proteínas de Ciclo Celular/química , Citarabina/uso terapéutico , Resultado Fatal , Variación Genética , Humanos , Hidroxiurea/uso terapéutico , Idarrubicina/uso terapéutico , Hibridación Fluorescente in Situ , Janus Quinasa 2 , Cariotipificación , Leucemia Mielógena Crónica BCR-ABL Positiva/tratamiento farmacológico , Leucemia Mielógena Crónica BCR-ABL Positiva/patología , Masculino , Persona de Mediana Edad , Sistemas de Lectura Abierta , Estructura Terciaria de Proteína , Proteínas Tirosina Quinasas/química , Proteínas Proto-Oncogénicas/química , ARN Mensajero/genética , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Prevención Secundaria , Análisis de Secuencia de ARN , Resultado del Tratamiento
16.
Hum Pathol ; 37(11): 1458-64, 2006 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-16949922

RESUMEN

A retrospective investigation of the JAK2 V617F mutation was carried out in DNA samples from 131 bone marrow (BM) core biopsy specimens corresponding to patients with polycythemia vera (PV) (n = 31), essential thrombocythemia (ET) (n = 31), chronic idiopathic myelofibrosis (CIM) (n = 18), as well as patients with normal BM and secondary reactive hyperplasia. We used the TaqMan polymerase chain reaction single nucleotide polymorphism genotyping assay to detect the specific JAK2 mutation. This technique allowed us to detect the JAK2 V617F mutation in a population containing at least 5% of homozygous mutants. Overall, the incidence of the JAK2 V617F mutation was 87% in PV, 67% in ET, and 66% in CIM. This approach proved to be reliable and more sensitive in detecting the mutation compared with that of initial studies on different materials but similar to that of recent work with various polymerase chain reaction-based techniques. Two essential findings arose from our study. First, this technique could be carried out with DNA samples, even partially degraded, from routinely processed BM core biopsy specimens. Second, after correlation with morphological features, it turned out that the characteristics of the megakaryocytes were more specific than the mutational status of JAK2 in characterizing ET and CIM. Concerning PV, as expected, the incidence of the JAK2 mutation was higher, but the morphological criteria were misleading in some cases, strongly suggesting that the combination of both histologic and molecular data would enable the characterization of virtually all cases.


Asunto(s)
Médula Ósea/química , Janus Quinasa 2/genética , Trastornos Mieloproliferativos/genética , Polimorfismo de Nucleótido Simple , Adulto , Anciano , Anciano de 80 o más Años , Biopsia , Femenino , Humanos , Janus Quinasa 2/análisis , Masculino , Persona de Mediana Edad , Trastornos Mieloproliferativos/patología , Mutación Puntual , Policitemia Vera/genética , Reacción en Cadena de la Polimerasa , Mielofibrosis Primaria/genética , Estudios Retrospectivos , Trombocitemia Esencial/genética
18.
Mol Cancer Res ; 11(8): 912-22, 2013 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-23604034

RESUMEN

UNLABELLED: The microRNA miR-150, a critical regulator of hematopoiesis, is downregulated in mixed-lineage leukemia (MLL). In this study, miR-150 acts as a potent leukemic tumor suppressor by blocking the oncogenic properties of leukemic cells. By using MLL-AF9-transformed cells, we demonstrate that ectopic expression of miR-150 inhibits blast colony formation, cell growth, and increases apoptosis in vitro. More importantly, ectopic expression of miR-150 in MLL-AF9-transformed cells completely blocked the development of myeloid leukemia in transplanted mice. Furthermore, gene expression profiling revealed that miR-150 altered the expression levels of more than 30 "stem cell signature" genes and many others that are involved in critical cancer pathways. In addition to the known miR-150 target Myb, we also identified Cbl and Egr2 as bona fide targets and shRNA-mediated suppression of these genes recapitulated the pro-apoptotic effects observed in leukemic cells with miR-150 ectopic expression. In conclusion, we demonstrate that miR-150 is a potent leukemic tumor suppressor that regulates multiple oncogenes. IMPLICATIONS: These data establish new, key players for the development of therapeutic strategies to treat MLL-AF9-related leukemia.


Asunto(s)
Regulación Leucémica de la Expresión Génica , Leucemia/genética , MicroARNs/genética , MicroARNs/metabolismo , Proteínas de Fusión Oncogénica/metabolismo , Oncogenes , Animales , Apoptosis/genética , Apoptosis/fisiología , Ciclo Celular/genética , Ciclo Celular/fisiología , Proteína 2 de la Respuesta de Crecimiento Precoz/genética , Proteína 2 de la Respuesta de Crecimiento Precoz/metabolismo , Perfilación de la Expresión Génica , Genes Supresores de Tumor , Células HEK293 , Humanos , Leucemia/metabolismo , Leucemia/patología , Ratones , Ratones Endogámicos C57BL , Proteínas de Fusión Oncogénica/genética , Proteínas Proto-Oncogénicas c-cbl/genética , Proteínas Proto-Oncogénicas c-cbl/metabolismo , Proteínas Proto-Oncogénicas c-myb/genética , Proteínas Proto-Oncogénicas c-myb/metabolismo , Transducción de Señal , Ensayos Antitumor por Modelo de Xenoinjerto
20.
J Exp Med ; 205(11): 2499-506, 2008 Oct 27.
Artículo en Inglés | MEDLINE | ID: mdl-18936236

RESUMEN

Most chromosomal translocations in myelodysplastic syndromes (MDS) and acute myeloid leukemia (AML) involve oncogenes that are either up-regulated or form part of new chimeric genes. The t(2;11)(p21;q23) translocation has been cloned in 19 cases of MDS and AML. In addition to this, we have shown that this translocation is associated with a strong up-regulation of miR-125b (from 6- to 90-fold). In vitro experiments revealed that miR-125b was able to interfere with primary human CD34(+) cell differentiation, and also inhibited terminal (monocytic and granulocytic) differentiation in HL60 and NB4 leukemic cell lines. Therefore, miR-125b up-regulation may represent a new mechanism of myeloid cell transformation, and myeloid neoplasms carrying the t(2;11) translocation define a new clinicopathological entity.


Asunto(s)
Diferenciación Celular/fisiología , Transformación Celular Neoplásica/metabolismo , Leucemia Mieloide Aguda/genética , MicroARNs/metabolismo , Síndromes Mielodisplásicos/genética , Células Mieloides/citología , Translocación Genética/genética , Transformación Celular Neoplásica/genética , Cartilla de ADN/genética , Humanos , Hibridación Fluorescente in Situ , Italia , Células Mieloides/fisiología , Reacción en Cadena de la Polimerasa/métodos , Regulación hacia Arriba/fisiología
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