RESUMEN
B-cell precursor acute lymphoblastic leukemia (BCP-ALL) is the most common malignancy in children. The Wnt signaling pathway has been found to be extensively involved in cancer onset and progression but its role in BCP-ALL remains controversial. We evaluate the role of the Wnt pathway in maintenance of BCP-ALL cells and resistance to chemotherapy. Gene expression profile revealed that BCP-ALL cells are potentially sensitive to modulation of Wnt pathway. Nalm-16 and Nalm-6 cell lines displayed low levels of canonical activation, as reflected by the virtually complete absence of total beta-catenin in Nalm-6 and the beta-catenin cell membrane distribution in Nalm-16 cell line. Canonical activation with Wnt3a induced nuclear beta-catenin translocation and led to BCP-ALL cell death. Lithium chloride (LiCl) also induced a cytotoxic effect on leukemic cells. In contrast, both Wnt5a and Dkk-1 increased Nalm-16 cell survival. Also, Wnt3a enhanced the in vitro sensitivity of Nalm-16 to etoposide (VP-16) while treatment with canonical antagonists protected leukemic cells from chemotherapy-induced cell death. Overall, our results suggest that canonical activation of the Wnt pathway may exerts a tumor suppressive effect, thus its inhibition may support BCP-ALL cell survival.
Asunto(s)
Antineoplásicos Fitogénicos/farmacología , Etopósido/farmacología , Leucemia-Linfoma Linfoblástico de Células Precursoras B/tratamiento farmacológico , Proteínas Wnt/metabolismo , Muerte Celular/efectos de los fármacos , Línea Celular Tumoral , Supervivencia Celular/efectos de los fármacos , Resistencia a Antineoplásicos/efectos de los fármacos , Regulación Neoplásica de la Expresión Génica , Humanos , Leucemia-Linfoma Linfoblástico de Células Precursoras B/fisiopatología , Transporte de Proteínas , Transducción de Señal , beta Catenina/metabolismoRESUMEN
Cell fate decisions are governed by a complex interplay between cell-autonomous signals and stimuli from the surrounding tissue. In vivo cells are connected to their neighbors and to the extracellular matrix forming a complex three-dimensional (3-D) microenvironment that is not reproduced in conventional in vitro systems. A large body of evidence indicates that mechanical tension applied to the cytoskeleton controls cell proliferation, differentiation and migration, suggesting that 3-D in vitro culture systems that mimic the in vivo situation would reveal biological subtleties. In hematopoietic tissues, the microenvironment plays a crucial role in stem and progenitor cell survival, differentiation, proliferation, and migration. In adults, hematopoiesis takes place inside the bone marrow cavity where hematopoietic cells are intimately associated with a specialized three 3-D scaffold of stromal cell surfaces and extracellular matrix that comprise specific niches. The relationship between hematopoietic cells and their niches is highly dynamic. Under steady-state conditions, hematopoietic cells migrate within the marrow cavity and circulate in the bloodstream. The mechanisms underlying hematopoietic stem/progenitor cell homing and mobilization have been studied in animal models, since conventional two-dimensional (2-D) bone marrow cell cultures do not reproduce the complex 3-D environment. In this review, we will highlight some of the mechanisms controlling hematopoietic cell migration and 3-D culture systems.
Asunto(s)
Animales , Humanos , Células de la Médula Ósea/citología , Técnicas de Cultivo de Célula/métodos , Movimiento Celular/fisiología , Células Madre Hematopoyéticas/fisiología , Esferoides Celulares/fisiología , Células del Estroma/fisiologíaRESUMEN
Cell fate decisions are governed by a complex interplay between cell-autonomous signals and stimuli from the surrounding tissue. In vivo cells are connected to their neighbors and to the extracellular matrix forming a complex three-dimensional (3-D) microenvironment that is not reproduced in conventional in vitro systems. A large body of evidence indicates that mechanical tension applied to the cytoskeleton controls cell proliferation, differentiation and migration, suggesting that 3-D in vitro culture systems that mimic the in vivo situation would reveal biological subtleties. In hematopoietic tissues, the microenvironment plays a crucial role in stem and progenitor cell survival, differentiation, proliferation, and migration. In adults, hematopoiesis takes place inside the bone marrow cavity where hematopoietic cells are intimately associated with a specialized three 3-D scaffold of stromal cell surfaces and extracellular matrix that comprise specific niches. The relationship between hematopoietic cells and their niches is highly dynamic. Under steady-state conditions, hematopoietic cells migrate within the marrow cavity and circulate in the bloodstream. The mechanisms underlying hematopoietic stem/progenitor cell homing and mobilization have been studied in animal models, since conventional two-dimensional (2-D) bone marrow cell cultures do not reproduce the complex 3-D environment. In this review, we will highlight some of the mechanisms controlling hematopoietic cell migration and 3-D culture systems.
Asunto(s)
Células de la Médula Ósea/citología , Técnicas de Cultivo de Célula/métodos , Movimiento Celular/fisiología , Células Madre Hematopoyéticas/fisiología , Esferoides Celulares/fisiología , Animales , Humanos , Células del Estroma/fisiologíaRESUMEN
Human B lineage lymphocyte precursors in chimeric nonobese diabetic/SCID mice transplanted with umbilical cord blood cells were directly compared with those present in normal bone marrow. All precursor subsets were represented and in nearly normal proportions. Cell cycle activity and population dynamics were investigated by staining for the Ki-67 nuclear Ag as well as by incorporation experiments using 5-bromo-2'-deoxyuridine. Again, this revealed that human B lymphopoiesis in chimeras parallels that in normal marrow with respect to replication and progression through the lineage. Moreover, sequencing of Ig gene rearrangement products showed that a diverse repertoire of V(H) genes was utilized by the newly formed lymphocytes but there was no evidence for somatic hypermutation. The newly formed B cells frequently acquired the CD5 Ag and had a short life span in the periphery. Thus, all molecular requirements for normal B lymphocyte formation are present in nonobese diabetic/SCID mice, but additional factors are needed for recruitment of B cells into a fully mature, long-lived pool. The model can now be exploited to learn about species restricted and conserved environmental cues for human B lymphocyte production.
Asunto(s)
Subgrupos de Linfocitos B/patología , Diabetes Mellitus Tipo 1/terapia , Hematopoyesis , Trasplante de Células Madre Hematopoyéticas , Inmunodeficiencia Combinada Grave/terapia , Animales , Antígenos de Diferenciación de Linfocitos B/biosíntesis , Antígenos de Diferenciación de Linfocitos B/genética , Médula Ósea/patología , Antígenos CD5/análisis , Ciclo Celular , Linaje de la Célula , Senescencia Celular , Diabetes Mellitus Tipo 1/sangre , Diabetes Mellitus Tipo 1/inmunología , Diabetes Mellitus Tipo 1/patología , Sangre Fetal/citología , Perfilación de la Expresión Génica , Reordenamiento Génico de Cadena Pesada de Linfocito B , Genes de Inmunoglobulinas , Supervivencia de Injerto , Humanos , Región Variable de Inmunoglobulina/genética , Ratones , Ratones Endogámicos NOD , Ratones SCID , Modelos Animales , Quimera por Radiación , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Inmunodeficiencia Combinada Grave/sangre , Inmunodeficiencia Combinada Grave/inmunología , Inmunodeficiencia Combinada Grave/patología , Organismos Libres de Patógenos Específicos , Trasplante HeterólogoRESUMEN
Estrogen is a negative regulator of lymphopoiesis and provides an experimental tool for probing relationships between lymphocyte precursors and stem cells. We found that expression of lymphocyte-associated genes and immunoglobulin (Ig) gene rearrangement occurred before CD45R acquisition. Lymphoid-restricted progenitors that were Lin(-)IL-7R alpha(+)c-kit(lo)TdT(+) (lineage marker(-), interleukin receptor 7 alpha(+), c-kit(lo) and terminal deoxynucleotidyl transferase(+)) were selectively depleted in estrogen-treated mice; within a less differentiated Lin-c-kit(hi) fraction, functional precursors of B and T, but not myeloid, cells were also selectively depleted. TdT and an Ig heavy chain transgene were detected within a hormone-regulated Lin(-)c-kit(hi)Sca-1(+)CD27(+)Flk-2(+)IL-7R alpha(-) subset of this multipotential progenitor population. Identification of these extremely early lymphoid precursors should facilitate investigation of the molecular mechanisms that control lineage-fate decisions in hematopoiesis.
Asunto(s)
Células de la Médula Ósea/fisiología , Estrógenos/fisiología , Hematopoyesis/fisiología , Linfocitos/citología , Linfocitos/fisiología , Animales , Células de la Médula Ósea/citología , Linaje de la Célula/inmunología , Ratones , Ratones Endogámicos BALB C , Ratones Endogámicos C57BLRESUMEN
This review describes an improved characterization of early B-lymphocyte precursors in mice and the remarkable sensitivity of the same cells to hormones. The nuclear enzyme terminal deoxynucleotidyl transferase (TdT) was used as a marker to image and characterize bone marrow cells lacking all lineage-associated markers. Most early TdT+ precursors have a distinctive density of c-kit and express the interleukin-7Ralpha chain, as well as flt-3/flk2, but lack CD34. An understanding of those cell surface properties made it possible to obtain highly enriched, viable cells with the potential to give rise to CD19+ lymphocytes in culture. A series of other flow cytometry and culture experiments suggested a possible differentiation sequence for these early pro-B cells. This new model was used to advantage in our studies of sex steroids. It appears that early precursors represent a hormone-sensitive control point for determining numbers of new B lymphocytes that are produced within bone marrow. We also compare and contrast these findings with B lymphopoiesis in humans.
Asunto(s)
Linfocitos B/inmunología , Estrógenos/fisiología , Células Madre Hematopoyéticas/inmunología , Animales , Antígenos CD19/inmunología , Antígenos de Diferenciación de Linfocitos B/inmunología , Células de la Médula Ósea/inmunología , Diferenciación Celular , División Celular , Linaje de la Célula , Humanos , Cadenas mu de Inmunoglobulina/metabolismo , Ratones , Modelos Biológicos , Esteroides/fisiología , Células del Estroma/inmunologíaRESUMEN
Inflammatory granulomatous reactions in liver elicited by schistosomal infection have been shown to function as active extramedullar myelopoietic sites, producing potentially all the myeloid lineages. We have now addressed the question of the extramedullar B lymphopoiesis in these sites. We have shown the presence of early B cell precursors (pro-B cells) in the granulomas by immunophenotyping. Their total number in the liver was equivalent to the pro-B cells in the bone marrow of one femur. In agreement with their phenotype, the RT-PCR analysis showed that these cells expressed RAG-1 and lambda5 genes. However, the conversion of the pro-B to pre-B cells was not observed and no clonogenic B cell precursors could be detected in semi-solid cultures stimulated by IL-7. The granulomatous stroma was shown to produce IL-7 and express c-kit, and was able to sustain the full B lymphopoiesis in vitro. Conversely, the granuloma supernatant was shown to inhibit actively the development of B lymphocytes. We conclude that the granuloma environment elicits homing and proliferation of totipotent hematopoietic precursors, and that it is permissive for early commitment to the B cell lineage, but the full extramedullar production of B cell is abrogated by soluble factors produced inside the granulomas.
Asunto(s)
Linfocitos B/inmunología , Granuloma/inmunología , Hematopoyesis Extramedular/inmunología , Parasitosis Hepáticas/inmunología , Esquistosomiasis/inmunología , Animales , Linfocitos B/citología , Células de la Médula Ósea , Diferenciación Celular , Células Cultivadas , Femenino , Granuloma/patología , Hematopoyesis Extramedular/genética , Proteínas de Homeodominio/genética , Proteínas de Homeodominio/metabolismo , Inmunofenotipificación , Interleucina-7/metabolismo , Parasitosis Hepáticas/patología , Masculino , Ratones , Ratones Endogámicos C3H , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Esquistosomiasis/patologíaRESUMEN
In schistosomiasis a systemic hyperplasia of the monomacrophagic cell lineage is associated with its mild modifications in myelograms and hemograms. We monitored the in vitro proliferation of myeloid precursors obtained from bone marrow, blood, spleen, and liver. The macrophage colony-forming unit (M-CFU) numbers were stable in bone marrow but increased progressively in spleen and in liver, reaching in each organ the values equivalent to one femur. The bone marrow had an increased production and enhanced capacity to release M-CFU. Their quantitative increase in blood and in peripheral tissues of schistosome-infected mice was associated with their qualitative modifications: augmented proliferative capacity, enhanced adhesion, and accelerated differentiation. The accelerated release of monomacrophage progenitors and their enhanced proliferation in peripheral tissues potentially account for the relatively low involvement of the bone marrow and for an efficient in situ production of phagocytes, which participate in host reactions to parasites.
Asunto(s)
Células de la Médula Ósea/citología , Células Madre Hematopoyéticas/citología , Leucopoyesis , Macrófagos/citología , Esquistosomiasis mansoni/sangre , Esquistosomiasis mansoni/patología , Animales , Recuento de Células , División Celular , Femenino , Hígado/patología , Masculino , Ratones , Ratones Endogámicos C3H , Bazo/patologíaRESUMEN
We studied the B-1 lymphocyte involvement in host reactions to parasites in the murine model of schistosomiasis. No modifications were observed in the prepostural phase of the disease. From the acute phase on, we observed sequentially an increase of Mac1- B-1 cells in the spleen, followed by their appearance in Peyer's patches and in mesenteric ganglia, suggesting that a fraction of splenic B-1 cells might follow this pathway of migration, acquiring progressively the Mac1 expression. These results are consistent with a primary activation of the splenic B cell compartment, with the subsequent mobilization of B-1 cells into the tissue involved by parasites. Conversely, we found no evidence of an increase of B-1 cells in the peritoneum, nor a mobilization of B-1 cells expressing the peritoneal phenotype (CD5lo, IgMhi) into the tissues involved by infection, despite the general inflammatory reactivity of peritoneal cells. In schistosomiasis, the peritoneal cavity B-1 cells on one side, and those involved in inflammatory reactions to parasites in the spleen, Peyer's patches, and mesenteric ganglia on the other, represent two distinct B-1 lymphocyte pools.
Asunto(s)
Subgrupos de Linfocitos B/inmunología , Esquistosomiasis mansoni/inmunología , Animales , Antígenos CD5/análisis , Femenino , Ganglios Simpáticos/inmunología , Inmunoglobulina M/análisis , Ganglios Linfáticos/inmunología , Recuento de Linfocitos , Masculino , Mesenterio/inervación , Ratones , Ratones Endogámicos C3H , Cavidad Peritoneal/citología , Ganglios Linfáticos Agregados/inmunología , Receptores de Antígenos de Linfocitos B/análisis , Bazo/inmunologíaRESUMEN
Chronic inflammatory periovular granulomatous reactions elicited in liver by schistosomal infection are a site of active myelopoiesis. We quantified the colony-forming cells (CFCs) in granulomas and found that the whole liver contains a number of CFCs roughly equivalent to 50% of a femur. Clonogenic analysis showed the presence of committed as well as pluripotent and totipotent CFCs. Long-term Dexter-type cultures showed that the granuloma-derived totipotent CFCs do not have self-renewal capacity. Hence, they did not correspond functionally to haematopoietic stem cells, despite the fact that the stroma established by adherent cells harvested from granulomas had the capacity to sustain long-term proliferation of bone-marrow-derived haematopoietic stem cells. We conclude that myelopoietic cytokines produced by inflammatory reactions in schistosomiasis elicit mobilization of bone marrow CFCs into the circulation, which can settle in hepatic granulomas. This environment may induce their proliferation and differentiation, but not their self-renewal, sustaining temporary production of myeloid cell lineages which nevertheless depends upon cell renewal from the bone marrow pool of haematopoietic precursors.
Asunto(s)
Células de la Médula Ósea/citología , Granuloma/fisiopatología , Hematopoyesis Extramedular/fisiología , Hematopoyesis/fisiología , Células Madre Hematopoyéticas/citología , Hepatitis Animal/fisiopatología , Animales , Células de la Médula Ósea/efectos de los fármacos , Diferenciación Celular , Células Cultivadas , Ensayo de Unidades Formadoras de Colonias , Eritropoyetina/farmacología , Femenino , Factor Estimulante de Colonias de Granulocitos y Macrófagos/farmacología , Granuloma/etiología , Células Madre Hematopoyéticas/efectos de los fármacos , Células Madre Hematopoyéticas/parasitología , Interleucina-3/farmacología , Masculino , Ratones , Ratones Endogámicos C3H , Óvulo/inmunología , Esquistosomiasis/complicaciones , Esquistosomiasis/fisiopatologíaRESUMEN
A case of spontaneously occurring infiltrative craniopharyngioma in a laboratory-reared gerbil is reported. The histopathological and ultrastructural features are described.
Asunto(s)
Craneofaringioma/veterinaria , Gerbillinae , Neoplasias Hipofisarias/veterinaria , Enfermedades de los Roedores/patología , Animales , Fosa Craneal Posterior , Craneofaringioma/patología , Femenino , Neoplasias Hipofisarias/patología , Hueso EsfenoidesRESUMEN
Transplantation of ascitic P-815 mastocytoma cells intradermally in the ears of syngeneic DBA/2J mice allows a simple and precise quantitation of tumor growth by ear swelling. Tumor growth was retarded and then arrested in allogeneic DBA/1J mice, whereas syngeneic hosts died as a result of tumor dissemination in draining lymph nodes, liver and spleen.