Asunto(s)
Cromosomas Humanos Par 10 , Cromosomas Humanos Par 11 , Proteínas de Unión al ADN/genética , Leucemia Mieloide/genética , Proteínas de Fusión Oncogénica/genética , Proto-Oncogenes , Factores de Transcripción , Translocación Genética , Enfermedad Aguda , Adulto , Secuencia de Aminoácidos , Niño , Feto , Perfilación de la Expresión Génica , N-Metiltransferasa de Histona-Lisina , Humanos , Masculino , Oxigenasas de Función Mixta , Datos de Secuencia Molecular , Proteína de la Leucemia Mieloide-Linfoide , Especificidad de Órganos , Proteínas Proto-OncogénicasRESUMEN
Chromosomal translocations are one of the hallmarks of human leukemias. These structural abnormalities result in the generation of genetic mutations that play a direct role in the transformation of hematopoietic stem cells. Some of the most common targets of these chromosomal rearrangements are the genes that encode the AML1/CBFbeta transcription factor complex. The AML1/CBFbeta complex plays a critical role in normal hematopoiesis, controlling the initiation of a transcriptional cascade required for the formation of definitive hematopoietic stem cells. Understanding how alterations in the normal biologic activity of this transcription factor complex lead to the initiation of leukemia will provide critical insights in the molecular pathogenesis of this disease. These insights in turn are likely to lead to the development of more rational approaches to the treatment of acute leukemia. In this review, we will summarize our current understanding of the mechanisms by which alterations in the activity of AML1/CBFbeta contribute to the development of leukemia.
Asunto(s)
Proteínas de Unión al ADN/fisiología , Leucemia/etiología , Proteínas Proto-Oncogénicas , Factores de Transcripción/fisiología , Subunidad alfa 2 del Factor de Unión al Sitio Principal , Proteínas de Unión al ADN/genética , Proteínas de Unión al ADN/farmacología , Hematopoyesis/efectos de los fármacos , Células Madre Hematopoyéticas/efectos de los fármacos , Humanos , Leucemia/genética , Proteínas de Fusión Oncogénica/genética , Proteínas de Fusión Oncogénica/farmacología , Factores de Transcripción/genética , Factores de Transcripción/farmacología , Translocación GenéticaAsunto(s)
Basófilos/patología , Cromosomas Humanos Par 21 , Cromosomas Humanos Par 8 , Leucemia Mieloide/genética , Leucemia Mieloide/patología , Translocación Genética , Enfermedad Aguda , Células de la Médula Ósea/patología , Preescolar , Subunidad alfa 2 del Factor de Unión al Sitio Principal , Femenino , Humanos , Proteínas de Fusión Oncogénica/metabolismo , Proteína 1 Compañera de Translocación de RUNX1 , Factores de Transcripción/metabolismoRESUMEN
PURPOSE: To develop a highly reproducible model of disseminated childhood neuroblastoma in mice to allow secondary evaluation of therapeutics against microscopic disseminated disease. METHODS: CB17/Icr SCID were injected i.v. with 10(3) to 5 x 10(6) human NB-1691 neuroblastoma cells. NB-1691 cells were detected by PCR for synaptophysin and tyrosine hydroxylase in peripheral blood, and bone marrow. Therapeutic studies evaluated topotecan and vincristine as single agents or in combination. Topotecan was administered i.v. daily for 5 days on two consecutive weeks. Courses were repeated every 21 days for three cycles. Vincristine (1 mg/kg) was administered i.v. every 7 days for nine consecutive weeks. Treatment started 11-21 days after tumor cell inoculation. RESULTS: Following injection of > or = 1 x 10(5) cells 100% of mice developed disease. Mice inoculated with 10(7) cells survived a median of 42 days. Survival time was a linear function of the cell inoculum. At autopsy, gross tumor was routinely detected in many organs in particular liver, ovaries, kidneys and adrenals. NB-1691 cells were detected by PCR in peripheral blood, and bone marrow. Immunohistochemical staining showed that lesions were strongly positive for synaptophysin, chromogranin A and negative for leukocyte common antigen. Topotecan (0.6 mg/kg) alone extended median survival from 44 days (controls) to 95 days. When treatment was started 21 days after inoculation of NB-1691 cells, topotecan extended median survival from 39 days (controls) to 91 and 99 days at dose levels of 0.3 and 0.6 mg/kg, respectively. Vincristine (1 mg/kg) extended survival by a median of 9.5 days. In combination with vincristine (1 mg/kg), median survival was increased to 141 days (topotecan 0.6 mg/kg) and 159 days (topotecan 1.0 mg/kg). CONCLUSION: This model of disseminated neuroblastoma is highly reproducible. As this model may more closely simulate childhood disease it may be a valuable adjunct in developing new approaches to advanced stage, poor prognosis neuroblastoma.
Asunto(s)
Modelos Animales de Enfermedad , Neuroblastoma , Animales , Antineoplásicos/uso terapéutico , Antineoplásicos Fitogénicos/uso terapéutico , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Ratones , Ratones SCID , Neuroblastoma/tratamiento farmacológico , Neuroblastoma/patología , Topotecan/uso terapéutico , Células Tumorales Cultivadas , Vincristina/uso terapéuticoRESUMEN
The requirement for CTLA-4 during the induction of peripheral T cell tolerance in vivo was investigated using naive TCR transgenic T cells lacking CTLA-4. CTLA-4(-/-) T cells are resistant to tolerance induction, as demonstrated by their proliferative responses, IL-2 production, and progression into the cell cycle. Following exposure to a tolerogenic stimulus in vivo and restimulation in vitro, wild-type T cells are blocked at the late G1 to S restriction point of the cell cycle. In contrast, CTLA-4(-/-) T cells enter into the S phase of the cell cycle, as shown by downregulation of p27(kip1), elevated cdk2 kinase activity, and Rb hyperphosphorylation. Thus, CTLA-4 has an essential role in determining the outcome of T cell encounter with a tolerogenic stimulus.
Asunto(s)
Antígenos de Diferenciación/inmunología , Anergia Clonal/inmunología , Inmunoconjugados , Linfocitos T/inmunología , Abatacept , Animales , Antígenos CD , Antígenos de Diferenciación/genética , Apoptosis , Antígeno CTLA-4 , Ciclo Celular , Citocinas/biosíntesis , Proteínas de Unión al ADN , Tolerancia Inmunológica , Técnicas In Vitro , Interleucina-2/biosíntesis , Activación de Linfocitos , Ratones , Ratones Endogámicos BALB C , Ratones Noqueados , Ratones Transgénicos , Linfocitos T/citología , Linfocitos T/metabolismoAsunto(s)
Anemia Refractaria con Exceso de Blastos/etiología , Protocolos de Quimioterapia Combinada Antineoplásica/efectos adversos , Aberraciones Cromosómicas , Cromosomas Humanos Par 8/genética , Irradiación Craneana/efectos adversos , Amplificación de Genes , Genes myc , Leucemia-Linfoma Linfoblástico de Células Precursoras B/terapia , Anemia Refractaria con Exceso de Blastos/inducido químicamente , Anemia Refractaria con Exceso de Blastos/tratamiento farmacológico , Anemia Refractaria con Exceso de Blastos/genética , Aneuploidia , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Asparaginasa/administración & dosificación , Asparaginasa/efectos adversos , Niño , Cladribina/administración & dosificación , Terapia Combinada , Citarabina/administración & dosificación , Citarabina/efectos adversos , Daunorrubicina/administración & dosificación , Daunorrubicina/efectos adversos , Resultado Fatal , Femenino , Humanos , Hidrocortisona/administración & dosificación , Hidrocortisona/efectos adversos , Cariotipificación , Mercaptopurina/administración & dosificación , Mercaptopurina/efectos adversos , Leucemia-Linfoma Linfoblástico de Células Precursoras B/tratamiento farmacológico , Leucemia-Linfoma Linfoblástico de Células Precursoras B/radioterapia , Prednisona/administración & dosificación , Prednisona/efectos adversos , Vincristina/administración & dosificación , Vincristina/efectos adversosRESUMEN
Previous studies from our laboratory have shown that prolonged exposure of mouse macrophages to IFN-beta interferes with their subsequent ability to become activated for tumor cell killing. Data reported here show that such inhibition is due to reduced production of NO, resulting from decreased transcription of the gene that encodes inducible NO synthase (iNOS; EC 1.14.13.39). The molecular basis for such suppression was shown to be, at least in part, decreased nuclear accumulation of tyrosine-phosphorylated Stat1alpha (pStat1alpha), and a consequent change in the nuclear ratio of pStat1alpha to non-transactivating pStat1beta. Reduced phosphorylation was observed despite the fact that time-course studies revealed greater than normal quantities of both Stat1alpha and Stat1beta proteins in macrophages that had been pre-exposed to IFN-beta. The decrease in nuclear pStat1alpha was demonstrated to involve an increase in the rate of turnover of phosphorylated protein. The homodimeric form of pStat1alpha is essential for the expression of both the iNOS and IFN-regulatory factor-1 genes (the product of the latter is necessary for full expression of the iNOS gene). These results have broad implications, because they suggest that limiting the availability of homodimeric pStat1alpha is a means by which down-regulation of genes containing promoter-linked IFN-gamma-activated sites might be achieved.
Asunto(s)
Proteínas de Unión al ADN/metabolismo , Interferón beta/metabolismo , Macrófagos/metabolismo , Óxido Nítrico Sintasa/genética , Transactivadores/metabolismo , Transcripción Genética , Animales , Núcleo Celular/metabolismo , Células Cultivadas , Medios de Cultivo , Citotoxicidad Inmunológica/inmunología , Elementos de Facilitación Genéticos , Factor 1 Regulador del Interferón , Interferón beta/farmacología , Interferón gamma/farmacología , Cinética , Lipopolisacáridos/farmacología , Macrófagos/citología , Macrófagos/efectos de los fármacos , Masculino , Ratones , Ratones Endogámicos C3H , FN-kappa B/metabolismo , Óxido Nítrico Sintasa/biosíntesis , Óxido Nítrico Sintasa de Tipo II , Fosfoproteínas/metabolismo , Fosforilación , Regiones Promotoras Genéticas , Proteínas Recombinantes , Factor de Transcripción STAT1 , Factores de Tiempo , Células Tumorales CultivadasRESUMEN
Primary low-grade B-cell lymphomas of the thymus are rare, with only 7 reported cases in the literature. We describe 3 cases of primary low-grade thymic lymphoma. All had histologic features of extranodal marginal zone lymphoma and were composed predominantly of small lymphocytes with variable components of monocytoid cells and plasma cells. Overt transformation to large cell lymphoma occurred in 1 case. The neoplastic cells were immunoreactive for the B-cell marker CD20 and were positive for bcl-2 in 2 cases. Two of 3 patients had a long-standing history of autoimmune disease. Based on these findings and those of previously reported cases, marginal zone lymphoma is the predominant type of low-grade thymic B-cell lymphoma. These tumors seem to be more common in patients with autoimmune disorders, and as observed with marginal zone lymphoma arising at other anatomic sites, they may undergo transformation to a higher grade lymphoma.
Asunto(s)
Linfoma de Células B/patología , Neoplasias del Timo/patología , Adulto , Anciano , Enfermedades Autoinmunes/complicaciones , Enfermedades Autoinmunes/patología , Biomarcadores de Tumor/análisis , Transformación Celular Neoplásica , Citogenética , Femenino , Humanos , Técnicas para Inmunoenzimas , Inmunofenotipificación , Linfoma de Células B/química , Linfoma de Células B/complicaciones , Linfoma de Células B/genética , Linfoma de Células B Grandes Difuso/patología , Masculino , Persona de Mediana Edad , Neoplasias del Timo/química , Neoplasias del Timo/complicaciones , Neoplasias del Timo/genéticaRESUMEN
To examine the role of CTLA-4 in Th cell differentiation, we used two newly generated CTLA-4-deficient (CTLA-4-/-) mouse strains: DO11. 10 CTLA-4-/- mice carrying a class II restricted transgenic TCR specific for OVA, and mice lacking CTLA-4, B7.1 and B7.2 (CTLA-4-/- B7.1/B7.2-/- ). When purified naive CD4+ DO11.10 T cells from CTLA-4-/- and wild-type mice were primed and restimulated in vitro with peptide Ag, CTLA-4-/- DO11.10 T cells developed into Th2 cells, whereas wild-type DO11.10 T cells developed into Th1 cells. Similarly, when CTLA-4-/- CD4+ T cells from mice lacking CTLA-4, B7. 1, and B7.2 were stimulated in vitro with anti-CD3 Ab and wild-type APC, these CTLA-4-/- CD4+ T cells produced IL-4 even during the primary stimulation, whereas CD4+ cells from B7.1/B7.2-/- mice did not produce IL-4. Upon secondary stimulation, CD4+ T cells from CTLA-4-/- B7.1/B7.2-/- mice secreted high levels of IL-4, whereas CD4+ T cells from B7.1/B7.2-/- mice produced IFN-gamma. In contrast to the effects on CD4+ Th differentiation, the absence of CTLA-4 resulted in only a modest effect on T cell proliferation, and increased proliferation of CTLA-4-/- CD4+ T cells was seen only during secondary stimulation in vitro. Administration of a stimulatory anti-CD28 Ab in vivo induced IL-4 production in CTLA-4-/- B7.1/B7.2-/- but not wild-type mice. These studies demonstrate that CTLA-4 is a critical and potent inhibitor of Th2 differentiation. Thus, the B7-CD28/CTLA-4 pathway plays a critical role in regulating Th2 differentiation in two ways: CD28 promotes Th2 differentiation while CTLA-4 limits Th2 differentiation.
Asunto(s)
Antígenos de Diferenciación/fisiología , Inmunoconjugados , Células Th2/citología , Células Th2/inmunología , Abatacept , Secuencia de Aminoácidos , Animales , Antígenos CD , Antígenos de Diferenciación/genética , Antígenos CD28/inmunología , Linfocitos T CD4-Positivos/metabolismo , Antígeno CTLA-4 , Diferenciación Celular/genética , Diferenciación Celular/inmunología , División Celular/genética , División Celular/inmunología , Citocinas/biosíntesis , Sueros Inmunes/farmacología , Interleucina-4/antagonistas & inhibidores , Interleucina-4/inmunología , Activación de Linfocitos/genética , Ratones , Ratones Endogámicos BALB C , Ratones Endogámicos , Ratones Transgénicos , Datos de Secuencia Molecular , Células Th2/metabolismoRESUMEN
The past year has seen significant advances in our understanding of the role of cytotoxic T lymphocyte antigen 4 (CTLA-4) in regulating T cell activation and tolerance. Recent studies indicate that CTLA-4 not only counterbalances CD28 signals but also can inhibit T cell responses independently of CD28. Recent work has also revealed a role for CTLA-4 in regulating Th1/Th2 differentiation. Manipulation of CTLA-4 in animal models of autoimmunity has shown that CTLA-4 regulates both the initiation and the progression of autoimmune diseases.
Asunto(s)
Antígenos de Diferenciación/metabolismo , Inmunoconjugados , Linfocitos T/inmunología , Abatacept , Animales , Antígenos CD/metabolismo , Apoptosis , Autoinmunidad , Antígeno B7-1/metabolismo , Antígeno B7-2 , Antígenos CD28/metabolismo , Linfocitos T CD4-Positivos/inmunología , Linfocitos T CD8-positivos/inmunología , Antígeno CTLA-4 , Diferenciación Celular , División Celular , Humanos , Tolerancia Inmunológica , Ligandos , Activación de Linfocitos , Glicoproteínas de Membrana/metabolismo , Receptores Inmunológicos/metabolismo , Transducción de Señal , Linfocitos T/citología , Timo/crecimiento & desarrolloRESUMEN
Myeloblastomas (granulocytic sarcomas) occurring within the central nervous system (CNS) are extremely rare lesions that may develop in patients with acute or chronic myeloproliferative disorders. The majority of such lesions involve brain or spinal cord by contiguous spread from meningeal or bony sites, rather than originating within the CNS parenchyma. We describe a patient with acute myelogenous leukemia in remission, who developed a purely intraparenchymal cerebellar myeloblastoma with megakaryocytic differentiation. The neoplastic cells expressed the megakaryocytic markers factor VIII-related antigen and platelet glycoprotein-IIIa (CD61), and showed ultrastructural features that were indicative of megakaryocytic differentiation. Clinically, myeloblastomas of the CNS invoke a broad differential diagnosis that includes abscess, hemorrhage, and metastatic neoplasms because of their intraparenchymal location and radiologic features. Although they are rare, myeloblastomas should be included in the histopathologic differential diagnosis of a poorly differentiated neoplasm occurring within the CNS, particularly in a patient with a history of myeloproliferative or myelodysplastic disease.
Asunto(s)
Neoplasias Cerebelosas/patología , Leucemia Megacarioblástica Aguda/patología , Leucemia Mieloide Aguda/patología , Leucemia Mieloide/patología , Antígenos CD/metabolismo , Diferenciación Celular , Neoplasias Cerebelosas/complicaciones , Neoplasias Cerebelosas/metabolismo , Diagnóstico Diferencial , Humanos , Integrina beta3 , Leucemia Megacarioblástica Aguda/complicaciones , Leucemia Megacarioblástica Aguda/metabolismo , Leucemia Mieloide/complicaciones , Leucemia Mieloide/metabolismo , Leucemia Mieloide Aguda/complicaciones , Leucemia Mieloide Aguda/metabolismo , Masculino , Persona de Mediana Edad , Síndromes Mielodisplásicos/complicaciones , Glicoproteínas de Membrana Plaquetaria/metabolismo , Recurrencia , Factor de von Willebrand/metabolismoRESUMEN
The effects of mast cell granules (MCGs) on macrophage-mediated lysis of P815 mastocytoma cells and nitric oxide (NO) production were studied. Murine peritoneal macrophages exhibited tumor cell killing and NO production only when activated with lipopolysaccharide (LPS) or interferon-gamma (IFN-gamma). Coincubation of macrophages with MCGs during LPS activation dose-dependently inhibited macrophage-mediated tumor cell lysis. The MCG effect was not due to inactivation or removal of LPS by MCG. The inhibitory effect was also not due to histamine or serotonin present in the MCGs. The granules were not toxic to macrophages or P815 mastocytoma cells. The effect of MCGs on macrophage-mediated tumor cell killing was evident whether MCGs were added before or after a 4-h exposure of macrophages to LPS. However, the inhibitory effect was not seen if MCGs were added after macrophages had been exposed to LPS for 24 h. To assess whether MCGs could inhibit a non-LPS trigger, MCGs were tested on macrophages activated with IFN-gamma. In these experiments, MCGs dose-dependently inhibited macrophage-mediated tumor cell killing induced by IFN-gamma, LPS, or IFN-gamma plus LPS. Furthermore, in parallel experiments, MCGs significantly inhibited macrophage NO production induced by LPS, IFN-gamma, or IFN-gamma plus LPS. Pretreatment of MCGs with diisopropylfluorophosphate, a serine protease inhibitor, only partially abrogated the effects of MCGs. The results demonstrate that MCGs inhibit both LPS- and IFN-gamma-induced macrophage killing of P815 cells and the inhibition is associated with the decrease of NO production.
Asunto(s)
Gránulos Citoplasmáticos/fisiología , Activación de Macrófagos , Macrófagos/fisiología , Mastocitos/fisiología , Sarcoma de Mastocitos/inmunología , Óxido Nítrico/metabolismo , Animales , Supervivencia Celular , Gránulos Citoplasmáticos/efectos de los fármacos , Interferón gamma/farmacología , Lipopolisacáridos/farmacología , Macrófagos/citología , Macrófagos/efectos de los fármacos , Masculino , Mastocitos/ultraestructura , Ratones , Ratones Endogámicos C57BL , Polimixina B/farmacología , Ratas , Ratas Sprague-Dawley , Proteínas Recombinantes , Células Tumorales CultivadasRESUMEN
Macrophages can become activated to kill both tumor cells and a variety of microbes. Results here show that synthesis of nitric oxide (NO), a mediator of many macrophage cytotoxic functions, was greatly increased when cells of the mouse macrophage cell line RAW 264.7 were costimulated with bacterial lipopolysaccharide (LPS) and interferon-gamma (IFN-gamma), compared to LPS alone. This increase paralleled increases in cytotoxicity. Northern analysis showed that increased production of NO was preceded by markedly enhanced expression of mRNA for the inducible form of macrophage NO synthase (mac-NOS), which catalyzes the synthesis of NO. Cycloheximide inhibited the induction of mac-NOS mRNA by IFN-gamma and LPS, indicating that expression of this mRNA required de novo protein synthesis. Elevated expression of mac-NOS mRNA was not due to an increase in its stability. Rather, the combination of IFN-gamma and LPS induced a much higher rate of transcription of the mac-NOS gene than did stimulation with LPS alone. These results provide one explanation of why priming and triggering stimuli, such as IFN-gamma and LPS, respectively, synergistically activate macrophages and may be applicable to explaining how IFN-gamma augments NO-dependent microbicidal activity in macrophages as well.
Asunto(s)
Aminoácido Oxidorreductasas/genética , Citotoxicidad Inmunológica , Expresión Génica , Interferón gamma/farmacología , Lipopolisacáridos/farmacología , Macrófagos/enzimología , Animales , Northern Blotting , Línea Celular , Cicloheximida/farmacología , Sinergismo Farmacológico , Activación de Macrófagos , Macrófagos/inmunología , Ratones , Óxido Nítrico/metabolismo , Óxido Nítrico Sintasa , ARN Mensajero/biosíntesisRESUMEN
Transforming growth factor-beta (TGF-beta) is known phenomenologically as a negative regulator of several functions of mouse bone marrow macrophages. The studies reported here extend this list by showing that TGF-beta can suppress cytolytic activity of mouse bone marrow culture-derived macrophages that already have become activated by IFN-gamma and LPS for tumor cell killing, as well as confirm that this cytokine can interfere with the induction of activation. Suppression was caused by a shift in the dose response curve for IFN-gamma rather than absolute inhibition; the 50% effective dose for IFN-gamma was increased approximately fourfold by treatment with TGF-beta. TGF-beta also decreased the absolute number of IFN-gamma R on the surfaces of pretreated macrophages by approximately 30 to 35%, without altering the affinity with which IFN-gamma bound. The increased concentration of IFN-gamma needed to produce the higher level of receptor occupancy explained the observed shift in the IFN-gamma dose response curve. These results suggest that TGF-beta mediates its negative regulatory effects on macrophage activation by interfering with coupling of the IFN-gamma R to the pathways that induce and maintain macrophage activation for tumor cell killing. Such effects are consistent with the view that TGF-beta is a negative regulator of macrophage activation for tumor cell killing. Because of this fact, neoplastic cells that secrete this cytokine may have a distinct survival advantage.
Asunto(s)
Interferón gamma/fisiología , Macrófagos/inmunología , Receptores Inmunológicos/metabolismo , Factor de Crecimiento Transformador beta/fisiología , Animales , Citotoxicidad Inmunológica/efectos de los fármacos , Regulación hacia Abajo , Inmunidad Celular/efectos de los fármacos , Activación de Macrófagos/efectos de los fármacos , Ratones , Receptores de InterferónRESUMEN
Nitric oxide production by macrophages required either simultaneous or sequential exposure to gamma interferon and lipopolysaccharide; exposure to lipopolysaccharide followed by exposure to gamma interferon gave little response. The apparently evanescent nature of the lipopolysaccharide signal, necessitating persistent stimulation, could be essential to down-regulating nitric oxide production after bacteria are cleared in vivo.