RESUMO
Adult T-cell leukemia/lymphoma (ATLL) patients have an extremely poor prognosis, partly due to their immunosuppressive state. The majority of ATLL patients have leukemic cells with phenotype similar to Tregs, prompting suggestions that ATLL cells themselves have immunosuppressive functions. In this study, we detected CD39 expression on ATLL cells, particularly frequent on aggressive subtypes. CD39 and CD73 convert extracellular adenosine triphosphate (ATP) into adenosine, a key player in Tregs' immunosuppression. In vitro culture, both CD39+ ATLL cells and normal Tregs converted rapidly extracellular ATP to AMP, which was disturbed by CD39 inhibitors, and was negated in the CD39 knockout MJ cell line. The proliferation of cocultured CD4+/CD8+ normal T cells was suppressed by CD39+ MJ cells, but not by CD39 knockout MJ cells. Supplemented ATP was exhausted by an EG7-OVA T-cell line with stable CD39 induction, but not by mock. When these cell lines were subcutaneously transplanted into murine flanks, Poly(I:C) peritoneal administration reduced tumor size to 1/3 in mock-transplanted tumors, but not in CD39 induced tumors. Overall, we found that ATLL cells express CD39 at a high rate, and our results suggest that this helps ATLL cells escape antitumor immunity through the extracellular ATPDase-Adenosine cascade. These findings will guide future clinical strategies for ATLL treatment.
Assuntos
Antígenos CD/genética , Apirase/genética , Regulação Leucêmica da Expressão Gênica , Tolerância Imunológica/genética , Imunomodulação/genética , Leucemia-Linfoma de Células T do Adulto/genética , Leucemia-Linfoma de Células T do Adulto/imunologia , Trifosfato de Adenosina/metabolismo , Animais , Antígenos CD/metabolismo , Apirase/metabolismo , Biomarcadores , Linhagem Celular Tumoral , Modelos Animais de Doenças , Perfilação da Expressão Gênica , Técnicas de Silenciamento de Genes , Xenoenxertos , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Imunofenotipagem , Leucemia-Linfoma de Células T do Adulto/diagnóstico , Leucemia-Linfoma de Células T do Adulto/metabolismo , Camundongos , Subpopulações de Linfócitos T/imunologia , Subpopulações de Linfócitos T/metabolismo , Subpopulações de Linfócitos T/patologiaRESUMO
Adult T-cell leukemia/lymphoma (ATL) is an aggressive neoplasm caused by human T-cell leukemia virus type 1 (HTLV-1). The HTLV-1 oncoprotein Tax plays an important role in ATL pathogenesis. ATL carries a poor prognosis due to chemotherapy resistance, stressing the need for alternative therapies. Here, we investigate the preclinical efficacy of the synthetic retinoid ST1926 in ATL and peripheral T-cell lymphomas. Clinically achievable concentrations of ST1926 induced a dramatic inhibition of cell proliferation in malignant T-cell lines and primary ATL cells with minimal effect on resting or activated normal lymphocytes. ST1926 induced apoptosis, DNA damage, and upregulation of p53 proteins in malignant T cells, whereas it caused an early downregulation of Tax proteins in HTLV-1-positive cells. In murine ATL, oral treatment with ST1926 prolonged survival and reduced leukemia cell infiltration, white blood cell counts, and spleen mass. In spleens of ST1926-treated animals, p53 and p21 proteins were upregulated, poly (ADP-ribose) polymerase was cleaved, and Tax transcripts were reduced. These results highlight the promising use of ST1926 as a targeted therapy for ATL.
Assuntos
Adamantano/análogos & derivados , Antineoplásicos/farmacologia , Cinamatos/farmacologia , Leucemia-Linfoma de Células T do Adulto/metabolismo , Leucemia-Linfoma de Células T do Adulto/patologia , Adamantano/administração & dosagem , Adamantano/farmacologia , Animais , Antineoplásicos/administração & dosagem , Apoptose/efeitos dos fármacos , Caspases/metabolismo , Pontos de Checagem do Ciclo Celular/efeitos dos fármacos , Linhagem Celular Transformada , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Cinamatos/administração & dosagem , Dano ao DNA , Modelos Animais de Doenças , Avaliação Pré-Clínica de Medicamentos , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Produtos do Gene tax/genética , Produtos do Gene tax/metabolismo , Humanos , Leucemia-Linfoma de Células T do Adulto/tratamento farmacológico , Leucemia-Linfoma de Células T do Adulto/genética , Leucemia-Linfoma de Células T do Adulto/mortalidade , Infiltração Leucêmica , Camundongos , Proteína Supressora de Tumor p53/genética , Proteína Supressora de Tumor p53/metabolismo , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
Adult T-cell leukemia/lymphoma (ATL) is a fatal malignancy caused by infection with human T-lymphotropic virus type-1 and there is no accepted curative therapy for ATL. We searched for biological active substances for the prevention and treatment of ATL from several species of herbs. The ATL cell growth-inhibitory activity and apoptosis assay showed that carnosol, which is an ingredient contained in rosemary (Rosmarinus officinalis), induced apoptosis in ATL cells. Next, to investigate the apoptosis-inducing mechanism of carnosol, we applied proteomic analysis using fluorescent two-dimensional differential gel electrophoresis and mass spectrometry. The proteomic analysis showed that the expression of reductases, enzymes in glycolytic pathway, and enzymes in pentose phosphate pathway was increased in carnosol-treated cells, compared with untreated cells. These results suggested that carnosol affected the redox status in the cells. Further, the quantitative analysis of glutathione, which plays the central role for the maintenance of intracellular redox status, indicated that carnosol caused the decrease of glutathione in the cells. Further, N-acetyl-L-cystein, which is precursor of glutathione, canceled the efficiency of carnosol. From these results, it was suggested that the apoptosis-inducing activity of carnosol in ATL cells was caused by the depletion of glutathione.
Assuntos
Abietanos/farmacologia , Eletroforese em Gel Bidimensional/métodos , Glutationa/metabolismo , Glutationa/fisiologia , Leucemia-Linfoma de Células T do Adulto/genética , Leucemia-Linfoma de Células T do Adulto/patologia , Proteômica/métodos , Rosmarinus/química , Abietanos/antagonistas & inibidores , Abietanos/uso terapêutico , Acetilcisteína/farmacologia , Células Cultivadas , Glutationa/deficiência , Glicólise/efeitos dos fármacos , Humanos , Leucemia-Linfoma de Células T do Adulto/tratamento farmacológico , Espectrometria de Massas , Terapia de Alvo Molecular , Oxirredução/efeitos dos fármacos , Via de Pentose Fosfato/efeitos dos fármacos , FitoterapiaRESUMO
DNA methylation plays critical roles in the development and differentiation of mammalian cells, and its dysregulation has been implicated in oncogenesis. This study was designed to determine whether DNA hypomethylation-associated aberrant gene expression is involved in adult T-cell leukemia (ATL) leukemogenesis. We isolated hypomethylated DNA regions of ATL cells compared with peripheral blood mononuclear cells from a carrier by a methylated CpG-island amplification/representational difference analysis method. The DNA regions identified contained MEL1, CACNA1H, and Nogo receptor genes. Sequencing using sodium bisulfite-treated genomic DNAs revealed the decreased methylated CpG sites, confirming that this method detected hypomethylated DNA regions. Moreover, these hypomethylated genes were aberrantly transcribed. Among them, MEL1S, an alternatively spliced form of MEL1 lacking the PR (positive regulatory domain I binding factor 1 and retinoblastoma-interacting zinc finger protein) domain, was frequently transcribed in ATL cells, and the transcriptional initiation sites were identified upstream from exons 4 and 6. Transfection of MEL1S into CTLL-2 cells conferred resistance against transforming growth factor beta (TGF-beta), suggesting that aberrant expression of MEL1S was associated with dysregulation of TGF-beta-mediated signaling. Although Tax renders cells resistant to TGF-beta, Tax could not be produced in most fresh ATL cells, in which MEL1S might be responsible for TGF-beta resistance. Our results suggest that aberrant gene expression associated with DNA hypomethylation is implicated in leukemogenesis of ATL.
Assuntos
Processamento Alternativo/genética , Proteínas de Ligação a DNA/genética , Regulação Neoplásica da Expressão Gênica/genética , Leucemia-Linfoma de Células T do Adulto/genética , Fatores de Transcrição/genética , Dedos de Zinco/genética , Adulto , Canais de Cálcio Tipo T/genética , Linhagem Celular Transformada , Mapeamento Cromossômico , Primers do DNA , DNA Complementar/genética , Proteínas de Ligação a DNA/química , Proteínas Ligadas por GPI , Vírus Linfotrópico T Tipo 1 Humano/genética , Humanos , Metilação , Modelos Moleculares , Proteínas da Mielina/genética , Receptor Nogo 1 , Reação em Cadeia da Polimerase , Conformação Proteica , Receptores de Superfície Celular/genética , Mapeamento por Restrição , Reação em Cadeia da Polimerase Via Transcriptase Reversa/métodos , Fatores de Transcrição/químicaRESUMO
We report the cloning and characterization of a novel cDNA termed C2H2-546 which encodes a C2H2-type zinc finger protein. C2H2-546 RNA is expressed in the HTLV-1 infected T cells examined which were derived from HAM-TSP patients, but not in T cells derived from ATL patients. The C2H2-546 gene is conserved in humans and primates and maps to chromosome 10q11.2, a site associated with a variety of cancers. Thus, C2H2-546 is a candidate regulatory molecule important in the formation of these tumors, and may serve as an important marker to distinguish HTLV-1 infected ATL versus HAM-TSP T cell lineages.
Assuntos
Cromossomos Humanos Par 10/genética , Regulação Viral da Expressão Gênica , Genes , Infecções por HTLV-I/genética , Vírus Linfotrópico T Tipo 1 Humano/fisiologia , Proteínas de Neoplasias/genética , Linfócitos T/metabolismo , Dedos de Zinco/genética , Sequência de Aminoácidos , Animais , Sequência de Bases , Cromossomos Artificiais de Levedura , DNA Complementar/genética , Drosophila melanogaster/genética , Humanos , Fatores de Transcrição Kruppel-Like , Leucemia-Linfoma de Células T do Adulto/genética , Leucemia-Linfoma de Células T do Adulto/patologia , Mamíferos/genética , Dados de Sequência Molecular , Proteínas de Neoplasias/biossíntese , Proteínas Nucleares , Paraparesia Espástica Tropical/genética , Paraparesia Espástica Tropical/patologia , Reação em Cadeia da Polimerase , Saccharomyces cerevisiae/genética , Especificidade da Espécie , Linfócitos T/virologia , Fatores de Transcrição , Células Tumorais CultivadasRESUMO
The t(6;11)(q27;23) is one of the most common translocations observed in patients with acute myeloid leukemia (AML). The translocation breakpoint involves the MLL gene, which is the human homolog of the Drosophila trithorax gene, at 11q23 and the AF6 gene at 6q27. Reverse transcriptase-polymerase chain reaction (RT-PCR) using an MLL sense primer and an AF6 antisense primer detected the MLL/AF6 fusion cDNA from three leukemia patients with the t(6;11) [two AML and one T-acute lymphoblastic leukemia (ALL)] and one cell line. The fusion point in the AF6 cDNA from these cases is identical, regardless of the leukemia phenotype. The ML-2 cell line, which was established from a patient with AML that developed after complete remission of T-cell lymphoma, has retained an 11q23-24 deletion from the lymphoma stage and has acquired the t(6;11) with development of AML. The ML-2 cells have no normal MLL gene on Southern blot analysis, which indicates that an intact MLL gene is not necessary for survival of leukemic cells.