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1.
Leukemia ; 31(12): 2780-2790, 2017 12.
Artigo em Inglês | MEDLINE | ID: mdl-28555079

RESUMO

The PD-L1/PD-1 pathway is a critical component of the immunosuppressive tumor microenvironment in acute myeloid leukemia (AML), but little is known about its regulation. We investigated the role of the MUC1 oncoprotein in modulating PD-L1 expression in AML. Silencing of MUC1 in AML cell lines suppressed PD-L1 expression without a decrease in PD-L1 mRNA levels, suggesting a post-transcriptional mechanism of regulation. We identified the microRNAs miR-200c and miR-34a as key regulators of PD-L1 expression in AML. Silencing of MUC1 in AML cells led to a marked increase in miR-200c and miR-34a levels, without changes in precursor microRNA, suggesting that MUC1 might regulate microRNA-processing. MUC1 signaling decreased the expression of the microRNA-processing protein DICER, via the suppression of c-Jun activity. NanoString (Seattle, WA, USA) array of MUC1-silenced AML cells demonstrated an increase in the majority of probed microRNAs. In an immunocompetent murine AML model, targeting of MUC1 led to a significant increase in leukemia-specific T cells. In concert, targeting MUC1 signaling in human AML cells resulted in enhanced sensitivity to T-cell-mediated lysis. These findings suggest MUC1 is a critical regulator of PD-L1 expression via its effects on microRNA levels and represents a potential therapeutic target to enhance anti-tumor immunity.


Assuntos
Antígeno B7-H1/genética , Regulação Leucêmica da Expressão Gênica , MicroRNAs/genética , Mucina-1/metabolismo , Animais , Antígeno B7-H1/metabolismo , Linhagem Celular Tumoral , Humanos , Imunomodulação/genética , Camundongos , Mucina-1/genética , Proteínas Proto-Oncogênicas c-jun/genética , Proteínas Proto-Oncogênicas c-jun/metabolismo , Ribonuclease III/genética , Ribonuclease III/metabolismo , Ativação Transcricional , Regulação para Cima
2.
Leukemia ; 26(11): 2343-52, 2012 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-22614176

RESUMO

The discovery of microRNA (miR) represents a novel paradigm in RNA-based regulation of gene expression and their dysregulation has become a hallmark of many a tumor. In virally associated cancers, the host-pathogen interaction could involve alteration in miR expression. Epstein-Barr virus (EBV)-encoded EBNA2 is indispensable for the capacity of the virus to transform B cells in vitro. Here, we studied how it affects cellular miRs. Extensive miR profiling of the virus-infected and EBNA2-transfected B lymphoma cells revealed that oncomiR miR-21 is positively regulated by this viral protein. Conversely, Burkitt's lymphoma (BL) cell lines infected with EBNA2 lacking P3HR1 strain did not show any increase in miR-21. EBNA2 increased phosphorylation of AKT and this was directly correlated with increased miR-21. In contrast, miR-146a was downregulated by EBNA2 in B lymphoma cells. Low miR-146a expression correlates with an elevated level of IRAK1 and type I interferon in EBNA2 transfectants. Taken together, the present data suggest that EBNA2 might contribute to EBV-induced B-cell transformation by altering miR expression and in particular by increasing oncomiR-like miR-21 and by affecting the antiviral responses of the innate immune system through downregulation of its key regulator miR-146a.


Assuntos
Antígenos Nucleares do Vírus Epstein-Barr/fisiologia , Herpesvirus Humano 4/genética , MicroRNAs/fisiologia , Proteínas Virais/fisiologia , Northern Blotting , Western Blotting , Linhagem Celular Tumoral , Antígenos Nucleares do Vírus Epstein-Barr/genética , Técnicas de Silenciamento de Genes , Humanos , MicroRNAs/genética , Proteínas Virais/genética
3.
Oncogene ; 29(9): 1316-28, 2010 Mar 04.
Artigo em Inglês | MEDLINE | ID: mdl-19966860

RESUMO

Epstein-Barr virus (EBV) encoded latent membrane protein 1 (LMP1) is noted for its transforming potential. Yet, it also acts as a cytostatic and growth-relenting factor in Burkitt's lymphoma (BL) cells. The underlying molecular mechanisms of the growth inhibitory property of LMP1 have remained largely unknown. In this study, we show that LMP1 negatively regulates a major oncogene, TCL1, in diffuse large B-cell lymphoma (DLBCL) and BL cells. MicroRNA (miR) profiling of LMP1 transfectants showed that among others, miR-29b, is upregulated. LMP1 diminished TCL1 by inducing miR-29b through C-terminus activation region 1 (CTAR1) and CTAR2. miR-29b locked nucleic acid (LNA) antisense oligonucleotide transfection into LMP1-expressing cells reduced miR-29b expression and consequently reconstituted TCL1, suggesting that LMP1 negatively regulates TCL1 through miR-29b upregulation. The miR-29b increase by LMP1 was due to an increase in the cluster pri-miR-29b1-a transcription, derived from human chromosome 7. Using pharmacological inhibitors, we found that p38 mitogen-activated protein kinase-activating function of LMP1 is important for this effect. The ability of LMP1 to negatively regulate TCL1 through miR-29b might underlie its B-cell lymphoma growth antagonistic property. As LMP1 is also important for B-cell transformation, we suggest that the functional dichotomy of this viral protein may depend on a combination of levels of its expression, lineage and differentiation of the target cells and regulation of miRs, which then directs the outcome of the cellular response.


Assuntos
Regulação da Expressão Gênica/efeitos dos fármacos , Herpesvirus Humano 4/metabolismo , MicroRNAs/metabolismo , Oncogenes/efeitos dos fármacos , Proteínas Proto-Oncogênicas/metabolismo , Proteínas da Matriz Viral/farmacologia , Linhagem Celular Tumoral , Herpesvirus Humano 4/química , Herpesvirus Humano 4/genética , Humanos , Linfoma de Células B/virologia , MicroRNAs/farmacologia , Oncogenes/genética , Proteínas Proto-Oncogênicas/genética , Transdução de Sinais/fisiologia
5.
Cancer Genet Cytogenet ; 130(2): 93-104, 2001 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-11675129

RESUMO

ETV6/CBFA2 (TEL/AML1) is the most frequent genetic abnormality associated with acute lymphoblastic leukemias in children, and is associated with a favorable prognosis. To investigate the influence of ETV6/CBFA2 on cellular transformation, the fusion gene was cloned into a murine ecotropic retroviral vector and transduced into IL-3-dependent Ba/F3 and 32Dcl.3 and IL-7-dependent IxN/2b murine hematopoietic cell lines. Different variants of ETV6/CBFA2, corresponding to CBFA2 alternatively spliced variants, and the reciprocal product CBFA2/ETV6, were stably expressed in each of these cell lines. However, although Western blot analysis demonstrated expression of each variant, none of the stable cell lines expressing CBFA2/ETV6 or the variants conferred factor-independent growth. We further investigated the effect of ETV6/CBFA2 expression in vivo by generating transgenic mice in which expression of the fusion was directed to lymphoid cells using the immunoglobulin heavy chain enhancer/promoter. Four founder mice were identified showing transmission and expression of the chimeric product. The mice were bred for five generations and followed for more than 24 months. The mice did not develop a malignant hematologic disorder, nor did they display histopathologic, morphologic, or immunophenotypic abnormalities, although ETV6/CBFA2 expression was confirmed in each line. We conclude that the expression of ETV6/CBFA2 alone is not sufficient for induction of growth factor independence in hematopoietic cell lines or hematologic disease in transgenic mice.


Assuntos
Transformação Celular Neoplásica , Neoplasias Hematológicas/etiologia , Neoplasias Hematológicas/genética , Células-Tronco Hematopoéticas/citologia , Células-Tronco Hematopoéticas/metabolismo , Proteínas de Fusão Oncogênica/genética , Animais , Western Blotting , Diferenciação Celular , Linhagem Celular , Subunidade alfa 2 de Fator de Ligação ao Core , Eletroporação , Elementos Facilitadores Genéticos , Citometria de Fluxo , Humanos , Cadeias Pesadas de Imunoglobulinas/genética , Leucemia/etiologia , Leucemia/genética , Camundongos , Camundongos Transgênicos , Plasmídeos/metabolismo , Regiões Promotoras Genéticas , Retroviridae/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Fatores de Tempo , Ativação Transcricional , Transdução Genética
6.
Blood ; 97(12): 3910-8, 2001 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-11389034

RESUMO

The molecular cloning of the t(5;10)(q33;q22) associated with atypical chronic myeloid leukemia (CML) is reported. Fluorescence in situ hybridization (FISH), Southern blot, and reverse transcriptase- polymerase chain reaction analysis demonstrated that the translocation resulted in an H4/platelet-derived growth factor receptor betaR (PDGFbetaR) fusion transcript that incorporated 5' sequences from H4 fused in frame to 3' PDGFbetaR sequences encoding the transmembrane, WW-like, and tyrosine kinase domains. FISH combined with immunophenotype analysis showed that t(5;10)(q33;q22) was present in CD13(+) and CD14(+) cells but was not observed in CD3(+) or CD19(+) cells. H4 has previously been implicated in pathogenesis of papillary thyroid carcinoma as a fusion partner of RET. The H4/RET fusion incorporates 101 amino acids of H4, predicted to encode a leucine zipper dimerization domain, whereas the H4/PDGFbetaR fusion incorporated an additional 267 amino acids of H4. Retroviral transduction of H4/PDGFbetaR, but not a kinase-inactive mutant, conferred factor-independent growth to Ba/F3 cells and caused a T-cell lymphoblastic lymphoma in a murine bone marrow transplantation assay of transformation. Mutational analysis showed that the amino-terminal H4 leucine zipper domain (amino acids 55-93), as well as H4 amino acids 101 to 386, was required for efficient induction of factor-independent growth of Ba/F3 cells. Tryptophan-to-alanine substitutions in the PDGFbetaR WW-like domain at positions 566/593, or tyrosine-to-phenylalanine substitutions at PDGFbetaR positions 579/581 impaired factor-independent growth of Ba/F3 cells. H4/PDGFbetaR is an oncoprotein expressed in t(5;10)(q33;q22) atypical CML and requires dimerization motifs in the H4 moiety, as well as residues implicated in signal transduction by PDGFbetaR, for efficient induction of factor-independent growth of Ba/F3 cells. (Blood. 2001;97:3910-3918)


Assuntos
Carcinoma Papilar/genética , Cromossomos Humanos Par 10 , Cromossomos Humanos Par 5 , Leucemia Mielogênica Crônica BCR-ABL Positiva/genética , Proteínas/genética , Receptor beta de Fator de Crescimento Derivado de Plaquetas/genética , Neoplasias da Glândula Tireoide/genética , Translocação Genética , Transformação Celular Neoplásica/genética , Cromossomos Humanos Par 10/genética , Cromossomos Humanos Par 5/genética , Clonagem Molecular , Análise Citogenética , Proteínas do Citoesqueleto , DNA de Neoplasias/genética , DNA de Neoplasias/isolamento & purificação , Rearranjo Gênico , Humanos , Leucemia Mielogênica Crônica BCR-ABL Positiva/etiologia , Leucemia Mielogênica Crônica BCR-ABL Positiva/patologia , Mutagênese , Células Mieloides/metabolismo , Células Mieloides/patologia , Proteínas de Fusão Oncogênica , Estrutura Terciária de Proteína , Proteínas/metabolismo , Transfecção
7.
Mol Cell ; 6(3): 693-704, 2000 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-11030348

RESUMO

STAT5 is activated in a broad spectrum of human hematologic malignancies. We addressed whether STAT5 activation is necessary for the myelo- and lymphoproliferative disease induced by TEL/JAK2 using a genetic approach. Whereas mice transplanted with bone marrow transduced with retrovirus expressing TEL/JAK2 develop a rapidly fatal myelo- and lymphoproliferative syndrome, reconstitution with bone marrow derived from Stat5ab-deficient mice expressing TEL/JAK2 did not induce disease. Disease induction in the Stat5a/b-deficient background was rescued with a bicistronic retrovirus encoding TEL/JAK2 and Stat5a. Furthermore, myeloproliferative disease was induced by reconstitution with bone marrow cells expressing a constitutively active mutant, Stat5a, or a single Stat5a target, murine oncostatin M (mOSM). These data define a critical role for Stat5a/b and mOSM in the pathogenesis of TEL/JAK2 disease.


Assuntos
Proteínas de Ligação a DNA/genética , Transtornos Linfoproliferativos/fisiopatologia , Proteínas do Leite , Transtornos Mieloproliferativos/fisiopatologia , Proteínas de Fusão Oncogênica/genética , Transativadores/genética , Animais , Southern Blotting , Células da Medula Óssea/patologia , Transplante de Medula Óssea , Ensaio de Unidades Formadoras de Colônias , DNA de Neoplasias/análise , Fibrose , Citometria de Fluxo , Técnicas de Transferência de Genes , Transtornos Linfoproliferativos/genética , Camundongos , Camundongos Mutantes , Mutagênese/fisiologia , Transtornos Mieloproliferativos/genética , Transplante de Neoplasias , Oncostatina M , Peptídeos/genética , Fenótipo , Retroviridae/genética , Fator de Transcrição STAT5
8.
Biochem Mol Biol Int ; 36(4): 803-9, 1995 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-8528142

RESUMO

The High Mobility Group protein HMG 17 has been isolated from human leukemia cells obtained from patients with chronic myelogenic leukemia (CML). The level of expression of HMG 17 was investigated Human leukemia cells have three times more HMG 17 than normal human leukocytes. Three other malignant tissues were also compared. Two of these breast adenocarcinoma and other intestine- also exhibit higher amounts of HMG 17. The elevated expression of HMG 17 suggests that the level of the protein may be associated with rates of cellular proliferation.


Assuntos
Proteínas de Grupo de Alta Mobilidade/sangue , Leucemia Mielogênica Crônica BCR-ABL Positiva/sangue , Leucócitos/metabolismo , Aminoácidos/análise , Animais , Bovinos , Cromatografia Líquida de Alta Pressão , Eletroforese em Gel Bidimensional , Eletroforese em Gel de Poliacrilamida , Proteínas de Grupo de Alta Mobilidade/biossíntese , Proteínas de Grupo de Alta Mobilidade/isolamento & purificação , Humanos , Peso Molecular , Valores de Referência , Timo/metabolismo
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