RESUMO
ABSTRACT: Platelet α-granules have numerous proteins, some synthesized by megakaryocytes (MK) and others not synthesized but incorporated by endocytosis, an incompletely understood process in platelets/MK. Germ line RUNX1 haplodeficiency, referred to as familial platelet defect with predisposition to myeloid malignancies (FPDMMs), is associated with thrombocytopenia, platelet dysfunction, and granule deficiencies. In previous studies, we found that platelet albumin, fibrinogen, and immunoglobulin G (IgG) were decreased in a patient with FPDMM. We now show that platelet endocytosis of fluorescent-labeled albumin, fibrinogen, and IgG is decreased in the patient and his daughter with FPDMM. In megakaryocytic human erythroleukemia (HEL) cells, small interfering RNA RUNX1 knockdown (KD) increased uptake of these proteins over 24 hours compared with control cells, with increases in caveolin-1 and flotillin-1 (2 independent regulators of clathrin-independent endocytosis), LAMP2 (a lysosomal marker), RAB11 (a marker of recycling endosomes), and IFITM3. Caveolin-1 downregulation in RUNX1-deficient HEL cells abrogated the increased uptake of albumin, but not fibrinogen. Albumin, but not fibrinogen, partially colocalized with caveolin-1. RUNX1 KD resulted in increased colocalization of albumin with flotillin and fibrinogen with RAB11, suggesting altered trafficking of both proteins. The increased uptake of albumin and fibrinogen, as well as levels of caveolin-1, flotillin-1, LAMP2, and IFITM3, were recapitulated by short hairpin RNA RUNX1 KD in CD34+-derived MK. To our knowledge, these studies provide first evidence that platelet endocytosis of albumin and fibrinogen is impaired in some patients with RUNX1-haplodeficiency and suggest that megakaryocytes have enhanced endocytosis with defective trafficking, leading to loss of these proteins by distinct mechanisms. This study provides new insights into mechanisms governing endocytosis and α-granule deficiencies in RUNX1-haplodeficiency.
Assuntos
Transtornos Herdados da Coagulação Sanguínea , Transtornos Plaquetários , Hemostáticos , Leucemia Eritroblástica Aguda , Leucemia Mieloide Aguda , Humanos , Megacariócitos/metabolismo , Caveolina 1/metabolismo , Fibrinogênio/metabolismo , Subunidade alfa 2 de Fator de Ligação ao Core/genética , Subunidade alfa 2 de Fator de Ligação ao Core/metabolismo , Endocitose , Albuminas/metabolismo , Imunoglobulina G , Proteínas de Membrana/metabolismo , Proteínas de Ligação a RNA/metabolismoRESUMO
Transcription factor RUNX1 is a master regulator of hematopoiesis and megakaryopoiesis. RUNX1 haplodeficiency (RHD) is associated with thrombocytopenia and platelet granule deficiencies and dysfunction. Platelet profiling of our study patient with RHD showed decreased expression of RAB31, a small GTPase whose cell biology in megakaryocytes (MKs)/platelets is unknown. Platelet RAB31 messenger RNA was decreased in the index patient and in 2 additional patients with RHD. Promoter-reporter studies using phorbol 12-myristate 13-acetate-treated megakaryocytic human erythroleukemia cells revealed that RUNX1 regulates RAB31 via binding to its promoter. We investigated RUNX1 and RAB31 roles in endosomal dynamics using immunofluorescence staining for markers of early endosomes (EEs; early endosomal autoantigen 1) and late endosomes (CD63)/multivesicular bodies. Downregulation of RUNX1 or RAB31 (by small interfering RNA or CRISPR/Cas9) showed a striking enlargement of EEs, partially reversed by RAB31 reconstitution. This EE defect was observed in MKs differentiated from a patient-derived induced pluripotent stem cell line (RHD-iMKs). Studies using immunofluorescence staining showed that trafficking of 3 proteins with distinct roles (von Willebrand factor [VWF], a protein trafficked to α-granules; epidermal growth factor receptor; and mannose-6-phosphate) was impaired at the level of EE on downregulation of RAB31 or RUNX1. There was loss of plasma membrane VWF in RUNX1- and RAB31-deficient megakaryocytic human erythroleukemia cells and RHD-iMKs. These studies provide evidence that RAB31 is downregulated in RHD and regulates megakaryocytic vesicle trafficking of 3 major proteins with diverse biological roles. EE defect and impaired vesicle trafficking is a potential mechanism for the α-granule defects observed in RUNX1 deficiency.
Assuntos
Leucemia Eritroblástica Aguda , Megacariócitos , Subunidade alfa 2 de Fator de Ligação ao Core/genética , Subunidade alfa 2 de Fator de Ligação ao Core/metabolismo , Receptores ErbB/metabolismo , Humanos , Megacariócitos/metabolismo , Proteínas rab de Ligação ao GTP/genética , Proteínas rab de Ligação ao GTP/metabolismo , Fator de von Willebrand/metabolismoRESUMO
BACKGROUND: Quercetin has potential against the Multidrug Resistance (MDR) phenotype, but with low bioavailability. The increase in the bioavailability can be obtained with nanostructures. OBJECTIVE: To analyze the effects of quercetin and its nanoemulsion on MDR and non-MDR cells. METHODS: We used high-pressure homogenization for nanoemulsion production; Trypan Blue for cytostatic/cytotoxicity assays; Epifluorescence microscope (with specific probes) for apoptosis and DNA damage; Real-Time PCR for gene expression; AutoDock Vina for docking and Flow Cytometry for efflux analysis. Quercetin exerted antiproliferative impact, induced apoptosis, necrosis and DNA damage on cells. RESULTS: Quercetin combined with vincristine showed an effect similar to verapamil (an ABCB1 inhibitor), and docking showed that it binds to ABCB1 in a similar region. Quercetin was also capable of altering ABCB1 gene expression. Quercetin in nanoemulsion maintained the cytotoxic and cytostatic effects of quercetin, which may increase bioavailability. Besides, the unloaded nanoemulsion was able to inhibit per se the efflux activity of ABCB1, demonstrating pharmacological action of this structure. CONCLUSION: Quercetin may be considered as a prospective drug to overcome resistance in cancer cells and its nanoemulsion can be an alternative for in vivo application.
Assuntos
Antineoplásicos/farmacologia , Resistência a Múltiplos Medicamentos/efeitos dos fármacos , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Leucemia Eritroblástica Aguda/tratamento farmacológico , Nanopartículas/química , Quercetina/farmacologia , Antineoplásicos/química , Apoptose/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Dano ao DNA , Ensaios de Seleção de Medicamentos Antitumorais , Emulsões , Citometria de Fluxo , Humanos , Leucemia Eritroblástica Aguda/patologia , Simulação de Acoplamento Molecular , Quercetina/química , Células Tumorais CultivadasRESUMO
BACKGROUND: PIM-1 is a kinase which has been related to the oncogenic processes like cell survival, proliferation, and multidrug resistance (MDR). This kinase is known for its ability to phosphorylate the main extrusion pump (ABCB1) related to the MDR phenotype. OBJECTIVE: In the present work, we tested a new mechanistic insight on the AZD1208 (PIM-1 specific inhibitor) under interaction with chemotherapy agents such as Daunorubicin (DNR) and Vincristine (VCR). MATERIALS AND METHODS: In order to verify a potential cytotoxic effect based on pharmacological synergism, two MDR cell lines were used: Lucena (resistant to VCR) and FEPS (resistant to DNR), both derived from the K562 non-MDR cell line, by MTT analyses. The activity of Pgp was ascertained by measuring accumulation and the directional flux of Rh123. Furthermore, we performed a molecular docking simulation to delve into the molecular mechanism of PIM-1 alone, and combined with chemotherapeutic agents (VCR and DNR). RESULTS: Our in vitro results have shown that AZD1208 alone decreases cell viability of MDR cells. However, co-exposure of AZD1208 and DNR or VCR reverses this effect. When we analyzed the ABCB1 activity AZD1208 alone was not able to affect the pump extrusion. Differently, co-exposure of AZD1208 and DNR or VCR impaired ABCB1 activity, which could be explained by compensatory expression of abcb1 or other extrusion pumps not analyzed here. Docking analysis showed that AZD1208 is capable of performing hydrophobic interactions with PIM-1 ATP- binding-site residues with stronger interaction-based negative free energy (FEB, kcal/mol) than the ATP itself, mimicking an ATP-competitive inhibitory pattern of interaction. On the same way, VCR and DNR may theoretically interact at the same biophysical environment of AZD1208 and also compete with ATP by the PIM-1 active site. These evidences suggest that AZD1208 may induce pharmacodynamic interaction with VCR and DNR, weakening its cytotoxic potential in the ATP-binding site from PIM-1 observed in the in vitro experiments. CONCLUSION: Finally, the current results could have a pre-clinical relevance potential in the rational polypharmacology strategies to prevent multiple-drugs resistance in human leukemia cancer therapy.
Assuntos
Compostos de Bifenilo/farmacologia , Resistência a Múltiplos Medicamentos , Leucemia Eritroblástica Aguda/tratamento farmacológico , Leucemia Eritroblástica Aguda/enzimologia , Simulação de Acoplamento Molecular , Inibidores de Proteínas Quinases/farmacologia , Proteínas Proto-Oncogênicas c-pim-1/antagonistas & inibidores , Tiazolidinas/farmacologia , Compostos de Bifenilo/química , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Ensaios de Seleção de Medicamentos Antitumorais , Humanos , Leucemia Eritroblástica Aguda/patologia , Conformação Molecular , Inibidores de Proteínas Quinases/química , Proteínas Proto-Oncogênicas c-pim-1/metabolismo , Tiazolidinas/química , Células Tumorais CultivadasRESUMO
La leucemia aguda es la enfermedad oncológica más frecuente en la infancia. La leucemia linfoblástica aguda representa el 75% y la mieloblástica aguda el 25% de ellas. La eritroleucemia es una entidad infrecuente, representando menos del 5% de las leucemias mieloblásticas agudas. Su definición ha variado a lo largo del tiempo. La OMS en 2017 define el subtipo de eritroleucemia cuando el porcentaje de eritroblastos representa el 80% de la celularidad total de la médula ósea. El presente trabajo, de tipo analítico, retrospectivo, tuvo como finalidad revisar los hallazgos de morfología, citometría de flujo, citogenética, respuesta al tratamiento y evolución de los casos previamente definidos como eritroleucemia, en nuestro centro, en los últimos 25 años y reclasificar aquellos que no cumplían con los nuevos criterios de la OMS 2017. Entre enero de 1990 y diciembre de 2015, se diagnosticaron 576 casos de leucemia mieloblástica aguda siendo 11 (1.9%) de ellos clasificados como eritroleucemia. Resultaron evaluables 10 casos. La distribución por sexo fue 1:1 y la edad mediana fue 5 (rango: 0.9-14) años. Seis pacientes presentaban antecedentes de síndrome mielodisplásico. Según los nuevos criterios, ninguno de los casos analizados puede ser actualmente definido como eritroleucemia. De acuerdo a la recategorización, fueron definidos como leucemias de subtipos de mal pronóstico, como leucemia aguda indiferenciada, sin diferenciación y megacarioblástica. Solo dos pacientes se encuentran libres de enfermedad, probablemente debido a estos subtipos desfavorables, sumado al antecedente frecuente de mielodisplasia.
Acute leukemia is the most frequent malignant disease in childhood. Acute lymphoblastic leukemia represents 75% and acute myeloblastic leukemia 25% of them. Erythroleukemia is a rare entity, corresponding to less than 5% of acute myeloblastic leukemia. Its definition has changed over the time. WHO in 2017 defines erythroleukemia when the percentage of erythroblasts represent 80% of the total cellularity of the bone marrow aspirate. This analytical and retrospective study was performed with the aim of reviewing morphology, flow cytometry and cytogenetic features, response to treatment and outcome of cases previously defined as erythroleukemia in our center during the last 25 years and, in addition to reclassify those cases which do not meet the new WHO 2017 criteria. From January 1990 to December 2015, 576 patients were diagnosed as acute myeloblastic leukemia and 11 (1.9%) of them were classified as erythroleukemia. Ten cases were evaluable. Sex distribution was 1:1 and the median age at diagnosis was 5 (range: 0.9-14) years. Six of them had presented with previous myelodysplastic syndrome. None of the analyzed cases can be currently defined as erythroleukemia, according to the new criteria. When reclassified, the cases were defined as leukemias of subsets with poor prognosis such as acute undifferentiated leukemia, without differentiation and megakaryoblastic leukemia. Only 2 patients remain leukemia-free and this could be explained both by the unfavorable prognosis of these leukemia subtypes, and the antecedent of myelodysplastic syndrome in most of the cases.
Assuntos
Humanos , Feminino , Lactente , Pré-Escolar , Criança , Adolescente , Organização Mundial da Saúde , Leucemia Eritroblástica Aguda/classificação , Leucemia Eritroblástica Aguda/diagnóstico , Argentina , Leucemia Eritroblástica Aguda/terapia , Estudos Retrospectivos , Resultado do Tratamento , Guias de Prática Clínica como Assunto , Progressão da Doença , Análise Citogenética/métodos , Citometria de Fluxo/métodosRESUMO
Thiosemicarbazone is a class of compounds with potential applications in medicine, presenting high capacity to inhibit the growth of cancer cells as well as low toxicity. Because of high interest in anticancer studies involving thiosemicarbazones as new chemotherapeutic agents, a synthetic thiosemicarbazone derivative, 4-N-(2'-methoxy-styryl)-thiosemicarbazone (MTSC) was evaluated in vivo against Ehrlich carcinoma in an animal model. In vivo results demonstrated that MTSC treatment induced the survival of mice and altered significantly the body weight of the surviving mice 12 days after tumor inoculation. Treatment with 30 mg/kg of MTSC exhibited effective cytotoxic activity with T/C values of 150.49% (1 dose) and 278% (2 doses). Its interaction with human serum albumin (HSA), which plays a crucial role in the biodistribution of a wide variety of ligands, was investigated by multiple spectroscopic techniques at 296 K, 303 K, and 310 K, as well as by theoretical calculations. The interaction between HSA and MTSC occurs via ground-state association in the subdomain IIA (Sudlow's site I). The binding is moderate (Ka ≈ 104 M-1), spontaneous, entropically, and enthalpically driven. Molecular docking results suggested hydrogen bonding and hydrophobic interactions as the main binding forces. Overall, the interaction HSA:MTSC could provide therapeutic benefits, improving its cytotoxic efficacy and tolerability.
Assuntos
Antineoplásicos/farmacologia , Carcinoma de Ehrlich/patologia , Leucemia Eritroblástica Aguda/patologia , Albumina Sérica Humana/metabolismo , Tiossemicarbazonas/farmacologia , Animais , Antineoplásicos/química , Apoptose , Carcinoma de Ehrlich/tratamento farmacológico , Carcinoma de Ehrlich/metabolismo , Proliferação de Células , Feminino , Humanos , Técnicas In Vitro , Leucemia Eritroblástica Aguda/tratamento farmacológico , Leucemia Eritroblástica Aguda/metabolismo , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Nus , Simulação de Acoplamento Molecular , Ligação Proteica , Conformação Proteica , Albumina Sérica Humana/química , Tiossemicarbazonas/química , Células Tumorais Cultivadas , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
Acute leukemia is the most frequent malignant disease in childhood. Acute lymphoblastic leukemia represents 75% and acute myeloblastic leukemia 25% of them. Erythroleukemia is a rare entity, corresponding to less than 5% of acute myeloblastic leukemia. Its definition has changed over the time. WHO in 2017 defines erythroleukemia when the percentage of erythroblasts represent 80% of the total cellularity of the bone marrow aspirate. This analytical and retrospective study was performed with the aim of reviewing morphology, flow cytometry and cytogenetic features, response to treatment and outcome of cases previously defined as erythroleukemia in our center during the last 25 years and, in addition to reclassify those cases which do not meet the new WHO 2017 criteria. From January 1990 to December 2015, 576 patients were diagnosed as acute myeloblastic leukemia and 11 (1.9%) of them were classified as erythroleukemia. Ten cases were evaluable. Sex distribution was 1:1 and the median age at diagnosis was 5 (range: 0.9-14) years. Six of them had presented with previous myelodysplastic syndrome. None of the analyzed cases can be currently defined as erythroleukemia, according to the new criteria. When reclassified, the cases were defined as leukemias of subsets with poor prognosis such as acute undifferentiated leukemia, without differentiation and megakaryoblastic leukemia. Only 2 patients remain leukemia-free and this could be explained both by the unfavorable prognosis of these leukemia subtypes, and the antecedent of myelodysplastic syndrome in most of the cases.
Assuntos
Leucemia Eritroblástica Aguda/classificação , Leucemia Eritroblástica Aguda/diagnóstico , Organização Mundial da Saúde , Adolescente , Argentina , Criança , Pré-Escolar , Análise Citogenética/métodos , Progressão da Doença , Feminino , Citometria de Fluxo/métodos , Humanos , Lactente , Leucemia Eritroblástica Aguda/terapia , Masculino , Guias de Prática Clínica como Assunto , Estudos Retrospectivos , Resultado do TratamentoRESUMO
Chemotherapy may be followed by multiple drug resistance (MDR). This is an obstacle in the treatment of cancer. It is therefore essential to understand the mechanisms underlying tumor resistance, especially those involved in the cell target/MDR relationship. To investigate this, the effects of exposing cells to UVB (to target DNA), UVA, and H2 O2 (to target the cell membrane) were observed in K562 (non MDR) and FEPS (MDR) cell lines. The K562 cells were more sensitive to UVA than the FEPS cells. The FEPS cell line was more resistant to H2 O2 than K562, only presenting cytotoxicity 72 h after being exposed to 40 mM, with no ROS increase until 48 h. Both cell lines were sensitive to UVB, presenting cytotoxicity after 24 h, mainly by apoptosis, and showed an increase in ROS levels. Our results indicate that agents acting on DNA may be able to overcome the MDR phenotype.
Assuntos
Apoptose/efeitos dos fármacos , Resistencia a Medicamentos Antineoplásicos , Peróxido de Hidrogênio/farmacologia , Raios Ultravioleta , Apoptose/efeitos da radiação , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos da radiação , Humanos , Células K562 , Leucemia Eritroblástica Aguda/metabolismo , Leucemia Eritroblástica Aguda/patologia , Fenótipo , Espécies Reativas de Oxigênio/metabolismoRESUMO
The gene expression of Oct-4, a transcription factor and hematopoietic stem cell marker, is higher in Lucena lines, which is MDR, and the gene Alox-5 has also been implicated in the differentiation of some cell lines. The aim of this study was to compare the response to PMA-induced differentiation in MDR and non-MDR cells. We observed the differentiation to megakaryocytes in the K562 cell line, which is non-MDR. The expression of Alox-5 and Nanog genes was downregulated and that of Mdr-1 was upregulated in K562 cells. The Lucena cell line contained a higher number of megakaryocytes than the non-MDR, but this number was not altered by PMA, as well as Mdr-1 gene expression. However, Alox-5 expression was downregulated. Alox-5, Mdr-1, Nanog, Oct-4 and Sox-2 basal expression was also evaluated in the K562, Lucena and FEPS (also MDR) cell lines. The transcription factors gene expression was similar in MDR cell lines. The expression of Alox-5 was higher in the non-MDR cell line, while FEPS had the lowest expression of this gene. The opposite pattern was observed for Mdr-1 gene expression. These results suggest that the Alox-5 gene might play a role in the differentiation of these cell lines.
Assuntos
Araquidonato 5-Lipoxigenase/genética , Diferenciação Celular/genética , Resistência a Múltiplos Medicamentos/genética , Leucemia Eritroblástica Aguda/genética , Células-Tronco Neoplásicas/patologia , Humanos , Células K562 , Leucemia Eritroblástica Aguda/patologia , Fenótipo , Reação em Cadeia da Polimerase , TranscriptomaRESUMO
BACKGROUND INFORMATION: In eukaryotic cells, autophagy is considered a lysosomal catabolic process which participates in the degradation of intracellular components in a vacuolar structure termed autolysosome. This pathway plays a significant role in the erythropoiesis process, contributing to the clearance of some organelles (such as mitochondria) that are not necessary in the mature red blood cells. Nevertheless, the role of autophagy in erythrocyte maturation has not been fully established. RESULTS: Here, we have demonstrated that hemin (a physiological erythroid maturation stimulator) is able to induce the expression of critical autophagic genes (i.e., Map1a1b (LC3), Beclin-1 gen, Atg5) in an erythroleukemia cell type. We have also shown that hemin increased the size of autophagic vacuoles which were labelled with LC3 and the degradative lysosomal marker dye quenched-bovine serum albumin. In addition, we have determined by Western blot a rise in the lipidated form of the autophagic protein LC3 (i.e., LC3-II) upon hemin treatment. Moreover, we provide evidence that hemin induces mitochondrial membrane depolarisation and that mitochondria sequestration by autophagy requires the active form of the NIX protein. CONCLUSIONS: We have found that the physiological erythroid maturation stimulator hemin is able to induce mitophagy in K562 cells, and that the autophagy adaptor NIX is necessary for mitophagy progression. K562 cells have been used as a relevant model to determine the possible therapeutic role of new differentiating compounds. SIGNIFICANCE: It has been proposed that autophagy induction is a feasible new therapeutic key in fighting cancer. Our results suggest that hemin is favoring erythroid maturation by inducing an autophagic response in K562 cells, being a possible therapeutic candidate that may help in the chronic myelogenous leukemia (CML) treatment.
Assuntos
Hemina/metabolismo , Leucemia Eritroblástica Aguda/metabolismo , Mitofagia , Regulação Leucêmica da Expressão Gênica , Humanos , Células K562 , Leucemia Eritroblástica Aguda/genética , Leucemia Eritroblástica Aguda/patologia , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Mitocôndrias/genética , Mitocôndrias/metabolismo , Mitocôndrias/patologia , Proteínas Proto-Oncogênicas/genética , Proteínas Proto-Oncogênicas/metabolismo , Proteínas Supressoras de Tumor/genética , Proteínas Supressoras de Tumor/metabolismoRESUMO
Acute erythroid leukemia (AML M6) is a hematopoietic neoplasm frequently described in cats and mice, rarely in other animal species. This report describes a case of AML M6 in a yearling Thoroughbred filly. Clinically the horse presented marked pale mucous membranes and exercise intolerance. In addition, the owner and referring veterinarian reported a 30-day history of progressive weight loss. The CBC revealed severe anemia and leukopenia by neutropenia. Cytology evaluation obtained from bone marrow fine needle aspirates evidenced inversion of the myeloid: erythroid ratio (0.2), with 48% of the nucleated cells corresponding to rubriblasts. In addition to the gross evidence of anemia, necropsy findings consisted of splenomegaly and lymphadenomegaly. The diagnosis of AML M6B was confirmed histologically due to splenomegaly and lymphadenomegaly, secondary to neoplastic metastasization.(AU)
Leucemia eritroide aguda (LMA M6) é um neoplasia hematopoiética descrita com frequência em gatos e camundongos, mas raramente nas demais espécies de animais. Esse relato descreve um caso dessa doença em um equino, fêmea, Puro Sangue Inglês de um ano de idade. Clinicamente, o equino apresentou acentuada palidez das mucosas, intolerância ao exercício e o proprietário relatava emagrecimento progressivo. No hemograma, foi observada anemia grave e leucopenia por neutropenia. No mielograma, havia inversão da relação mieloide:eritroide (0,2) e 48% das células nucleadas da medula óssea correspondiam a rubriblastos. Na necropsia, além de evidências de anemia, havia esplenomegalia e linfadenomegalia. O diagnóstico de LMA M6B foi confirmado histologicamente e o aumento do baço e dos linfonodos foi decorrente de metastatização.(AU)
Assuntos
Animais , Feminino , Doenças dos Cavalos , Leucemia Eritroblástica Aguda/diagnóstico , Leucemia Eritroblástica Aguda/veterinária , Células Eritroides/patologiaRESUMO
FORMA FARMACÉUTICA: bulbo DENOMINACIÓN COMÚN INTERNACIONAL: arabinósido de citosina. COMPOSICIÓN: cada bulbo contiene 100 mg y 500 mg de arabinósido de citosina en solución. CATEGORÍA FARMACOLÓGICA: antineoplásico, agente citotóxico, antimetabolito, analógo de las pirimidinas. FARMACOCINÉTICA: la biodisponibilidad por VO es escasa (menor que 20 %). La distribución es amplia y rápida por los tejidos. Atraviesa las barreras placentarias y hematoencefálica, alcanza el LCR hasta 40â50 por ciento de la concentración plasmática. Es metabolizado por citidina desaminasa, dando lugar fundamentalmente a arabinósido de uracilo, que es un metabolito inactivo y a trifosfato de aracitidina (activo). La desaminación se produce en el hígado, plasma y tejidos periféricos. Se elimina por la orina (± 80 por ciento) en las primeras 24 h. La vida media de eliminación terminal es 1-3 h. INDICACIONES: leucemia linfocítica y mielocítica aguda y leucemia meníngea. También se emplea en esquemas de segunda o tercera línea de linfomas no Hodgkin y leucemia mieloide crónica. Eritroleucemia. CONTRAINDICACIONES: hipersensibilidad conocida a la citosina. Pacientes con depresión de la médula ósea, enfermedades debilitantes e infecciones virales recientes como varicela o herpes zoster. USO EN POBLACIONES ESPECIALES: LM: datos no disponibles. E: categoría de riesgo D PRECAUCIONES: LM: no se conoce su excreción por la leche humana; no obstante, se recomienda suspender la lactancia materna durante la administración del fármaco. CARCINOGENICIDAD: grupo de riesgo 3. Los efectos depresores de la médula ósea de la citarabina pueden dar lugar a un aumento de la incidencia de infecciones, retardo en la cicatrización y hemorragia gingival. Deben ser cuidadosamente monitoreados los recuentos hemáticos. Si el recuento de leucocitos arroja CAN menor que 1 000 células/mm3 y las plaquetas están por debajo de 50 000 celulas/mm3, el tratamiento debe ser interrumpido. Los valores pueden continuar bajando aún después de que la administración de citarabina sea suspendida. El tratamiento puede reiniciarse cuando existen signos evidentes de recuperación de la médula ósea. Cuando se administran de forma rápida altas dosis por vía IV, los pacientes pueden presentar náusea y vómito durante algunas horas después de la inyección; este problema se presenta en forma menos severa cuando se administra por infusión. En pacientes con enfermedad hepática previa se deberán suministrar dosis menores de citosina, ya que en el hígado ocurre el proceso de detoxificación de este medicamento. Cuando tiene lugar una lisis celular rápida, se deben tomar las debidas precauciones para evitar hiperuricemia y hiperuricosuria y el riesgo de nefropatía por ácido úrico. La neurotoxicidad está asociada con los tratamientos de altas dosis y pueden presentarse como: toxicidad cerebelar aguda o puede ser severa con convulsiones y/o coma, incluso suele ser retardada, hasta 3â8 días después que el tratamiento haya comenzado. El riesgo de toxicidad cerebelar se incrementa cuando el aclaramiento de creatinina sea inferior a 60 mL/min, edad mayor de 50 años, lesión preexistente del SNC y niveles de fosfatasa alcalina mayor que tres veces el límite superior normal. La conjuntivitis es prevenida y tratada con gotas de solución salina y/o corticosteroides. Como profilaxis, las gotas oculares deben comenzarse de 6 a 12 h antes de iniciar el tratamiento con la citarabina, y continuar hasta 24 h después de haber finalizado esta. El término de altas dosis se define como dosis IV de 2 a 3 g/m2/dosis, cada 12â24 h, por 4â12 dosis o de 36 g/m2 en monoterapia, generalmente combinado con otros agentes utilizados en tratamientos con altas dosis de quimioterapia. Puede presentarse el llamado síndrome de la citarabina que se caracteriza por fiebre, mialgia, dolor óseo, dolor torácico, rash maculopapular, astenia y conjuntivitis, puede ocurrir de 6 a 12 h después de la administración de la citarabina. Puede ser tratado de manera eficaz con...(AU)
Assuntos
Humanos , Linfoma não Hodgkin/terapia , Leucemia Linfoide/terapia , Leucemia Eritroblástica Aguda/terapia , Leucemia Mieloide/terapia , Citarabina/uso terapêuticoRESUMO
The JAK/STAT pathway is constitutively activated in myeloproliferative neoplasms and can be inhibited by ruxolitinib, a selective JAK1/2 inhibitor. The JAK2(V617F) mutation leads to constitutive STAT3 phosphorylation and potentially leads to inhibition of Stathmin 1 activity via STAT3. In support of this hypothesis, we found that, in HEL JAK2(V617F) cells, ruxolitinib treatment decreased STAT3 and Stathmin 1 association, induced Stathmin 1 activation and microtubule instability. Silencing of Stathmin 1 significantly reduced cell proliferation and clonal growth, and increased apoptosis induced by ruxolitinib. Stathmin 1 silencing also prevented ruxolitinib-induced microtubule instability. To phenocopy the effect of Stathmin 1 inhibition, cells were treated with paclitaxel, a microtubule-stabilizing drug, in association or not with ruxolitinib; combined treatment significantly increased apoptosis, when compared to monotherapy. Notably, Stathmin 1 mRNA levels were highly expressed in CD34(+) cells from primary myelofibrosis patients. We then proposed that an undesired effect of ruxolitinib treatment may constitute Stathmin 1 activation and microtubule instability in JAK2(V617F) cells. Induction of microtubule stability, through Stathmin 1 silencing or paclitaxel treatment, combined with ruxolitinib could be an effective strategy for promoting apoptosis in JAK2(V617F) cells.
Assuntos
Apoptose/efeitos dos fármacos , Janus Quinase 2/antagonistas & inibidores , Pirazóis/farmacologia , Estatmina/metabolismo , Adulto , Idoso , Idoso de 80 Anos ou mais , Apoptose/genética , Western Blotting , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Proliferação de Células/genética , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Humanos , Janus Quinase 2/genética , Janus Quinase 2/metabolismo , Leucemia Eritroblástica Aguda/genética , Leucemia Eritroblástica Aguda/metabolismo , Leucemia Eritroblástica Aguda/patologia , Microscopia Confocal , Pessoa de Meia-Idade , Mutação de Sentido Incorreto , Transtornos Mieloproliferativos/genética , Transtornos Mieloproliferativos/metabolismo , Nitrilas , Paclitaxel/farmacologia , Pirimidinas , Interferência de RNA , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Estatmina/genética , Moduladores de Tubulina/farmacologia , Adulto JovemRESUMO
Leukemia cells produce acidic metabolites due to their high metabolic condition. An alkaline pHi (intracellular pH) shift, caused by activation of the Na+/H+ exchange, is an important event in the mechanism of growth factor activity. However, the role of the Na(+)/H(+) exchanger in the survival of erythroleukemia TF-1 cells has not yet been studied in detail. The aim of this study was to identify the effects of 5-(N-ethyl-N-isopropyl) amiloride (EIPA), a highly specific blocker of the Na(+)/H(+) exchanger, on the survival of SCF-dependent TF-1 cells. The effects of EIPA on survival and mitochondrial membrane potential were studied when exposing wild type TF-1 cells and TF-1 cells expressing bcl-2 to EIPA for 48h. Ectopic expression of the bcl-2 gene maintained a mildly alkaline pH and prevented the simultaneous appearance of apoptosis and autophagy (typically displayed by TF-1 cells) in the presence of EIPA. Consistent with Stem Cell Factor (SCF) function, we found that this molecule rescued TF-1 cells during autophagy but not apoptosis, allowing these cells to subsequently respond to GM-CSF. Serum deprivation or SCF withdrawal induced cell death at 36h in TF-1 and TF-1 neo cells, whereas TF-1/bcl-2 cells tended to undergo apoptosis and show acidic vacuoles after 96h, pointing to a transient anti-apoptotic effect. The present study shows the suppressive effect of EIPA on the proliferation of leukemia cell line stimulated with SCF, apparently by decreasing the mitochondria membrane potential and averting alkalinization. Through the constitutive expression of bcl-2, TF-1 cells were survival factor independent. Proliferation in these cells was not affected by EIPA at the concentrations used against parental TF-1 cells, indicating that the inhibitory effect in SCF-stimulated cells can be attributed to specific blocking of the Na(+)/H(+) exchanger.
Assuntos
Regulação Leucêmica da Expressão Gênica , Leucemia Eritroblástica Aguda/metabolismo , Leucemia/tratamento farmacológico , Trocadores de Sódio-Hidrogênio/antagonistas & inibidores , Trocadores de Sódio-Hidrogênio/química , Fator de Células-Tronco/metabolismo , Amilorida/análogos & derivados , Amilorida/química , Apoptose , Autofagia , Ciclo Celular , Linhagem Celular Tumoral , Proliferação de Células , Separação Celular , Sobrevivência Celular , Corantes Fluorescentes/química , Humanos , Concentração de Íons de Hidrogênio , Leucemia/metabolismo , Leucemia Eritroblástica Aguda/patologia , Potenciais da Membrana , Membranas Mitocondriais/metabolismo , Proteínas Proto-Oncogênicas c-bcl-2/metabolismoRESUMO
The OCT4 transcription factor is a crucial stem cells marker and it has been related to the cancer stem cells concept. Moreover, it has also been associated to the multiple drug resistance (MDR) phenotype. Our first results pointed out a straight relation between OCT4 and ABC transporters in K562-derivative MDR (Lucena) cells. Sequencing of ABC promoters did not reveal any mutation that could explain the differential expression of OCT4 in Lucena cells. Furthermore, sequencing of the homeobox domain region from the OCT4 gene isolated from both cell lines evinced, for the first time, that this transcription factor is a target of mutations and might be related to the MDR phenotype. The encountered mutations implied in several amino acids substitutions in both cell lines. K562 had seven amino acids substituted (three of them exclusive), while Lucena had 13 substitutions (nine of them exclusive). In addition, an in silico search for phosphorylation motifs within the amino acid stretch compared showed that human normal OCT4 has seven potential phosphorylation motifs. However, K562 has lost one phosphorylation motif and Lucena two of them. These findings bring OCT4 as an important target for cancer treatment, especially those resistant to chemotherapy.
Assuntos
Resistência a Múltiplos Medicamentos/genética , Leucemia Eritroblástica Aguda/genética , Fator 3 de Transcrição de Octâmero/genética , Linhagem Celular Tumoral , Humanos , Leucemia Eritroblástica Aguda/tratamento farmacológico , Leucemia Eritroblástica Aguda/patologia , Mutação , Células-Tronco Neoplásicas/patologia , FosforilaçãoAssuntos
Humanos , Ácidos Graxos/farmacologia , Globinas/genética , Fenilbutiratos/farmacologia , Células Cultivadas , Células Precursoras Eritroides/efeitos dos fármacos , Células Precursoras Eritroides/metabolismo , Ácidos Graxos/química , Hemoglobina Fetal/biossíntese , Hemoglobinopatias/sangue , Hemoglobinopatias/tratamento farmacológico , Hemoglobinopatias/genética , Leucemia Eritroblástica Aguda , Fenilacetatos/farmacologia , Fenilbutiratos/química , Regiões Promotoras Genéticas/efeitos dos fármacos , Relação Estrutura-Atividade , Células Tumorais Cultivadas , Regulação para Cima/efeitos dos fármacosRESUMO
Different molecules regulate the response of tumoral tissues to ionizing radiation. The objective of this work was to determine if HLA-G1 expression modulates the radiosensitivity of human tumoral cell lines. To this end, human melanoma M8 and human erythroleukemia K562 cell lines, with their correspondent HLA-G1 negative and positive variants, were gamma irradiated and the survival frequency was determined by clonogenic assay. The survival fraction of HLA-G1 expressing cells was around 60% of HLA-G1 negative cells. The generation of acidic vesicular organelles was higher in HLA-G1 positive cells. Apoptosis levels showed statistically significant differences only in K562 cells, whereas the variation in G2/M cycle progression was only significant in M8 cells. In addition, irradiation diminished cell-surface HLA-G1 and increased soluble HLA-G1 levels. Soluble HLA-G1 has no influence on cell survival in any cell line. In summary, we could demonstrate that HLA-G1 confers higher radiosensitivity to HLA-G1 expressing cells.
Assuntos
Biomarcadores Tumorais/metabolismo , Antígenos HLA-G/metabolismo , Leucemia Eritroblástica Aguda/radioterapia , Melanoma/radioterapia , Tolerância a Radiação , Apoptose , Ciclo Celular , Linhagem Celular Tumoral , Sobrevivência Celular , Raios gama , Antígenos HLA-G/genética , Humanos , Células K562 , Leucemia Eritroblástica Aguda/imunologia , Melanoma/imunologiaRESUMO
New nanobiocomposites that combine nanoparticles and biomolecules have been shown very relevant for medical applications. Recently, cancer diagnostics and treatment have benefited from the development of nanobiocomposites, in which metallic or magnetic nanoparticles are conjugated with specific biomolecules for selective cell uptake. Despite recent advances in this area, the biomedical applications of these materials are still limited by the low efficiency of functionalization, low stability, among other factors. In this study, we report the synthesis of jacalin-conjugated gold nanoparticles, a nanoconjugate with potential application in medical areas, especially for cancer diagnosis. Jacalin is a lectin protein and it was employed due to its ability to recognize the Galß1-3GalNAc disaccharide, which is highly expressed in tumor cells. Gold nanoparticles (AuNPs) were synthesized in the presence of generation 4 polyamidoamine dendrimer (PAMAM G4) and conjugated with fluorescein isothiocyanate (FITC)-labeled jacalin. The AuNPs/jacalin nanoconjugates were characterized by transmission electron microscopy (TEM), dynamic light scattering (DLS) and vibrational spectroscopy (FTIR). We also performed an investigation using isothermal titration calorimetry (ITC) and fluorescence quenching measurements to understand the interactions occurring between the AuNPs and jacalin, which revealed that the nanoconjugate formation is driven by an entropic process with good affinity. Furthermore, in vitro tests revealed that the AuNPs/jacalin-FITC nanoconjugates exhibited higher affinity for leukemic K562 cells than for healthy mononuclear blood cells, which could be useful for biomedical applications, including cancer cells imaging.
Assuntos
Rastreamento de Células/métodos , Nanopartículas Metálicas/química , Lectinas de Plantas/química , Biomarcadores Tumorais , Dicroísmo Circular , Dendrímeros , Estabilidade de Medicamentos , Feminino , Fluoresceína-5-Isotiocianato , Corantes Fluorescentes , Ouro , Humanos , Células K562 , Leucemia Eritroblástica Aguda/diagnóstico , Leucócitos Mononucleares/citologia , Masculino , Nanopartículas Metálicas/ultraestrutura , Microscopia Eletrônica de Transmissão , Nanoconjugados/química , Nanoconjugados/ultraestrutura , Nylons , Espectrofotometria , Espectroscopia de Infravermelho com Transformada de Fourier , TermodinâmicaRESUMO
Certain aspects of tumors that may influence areas of basic biology and medicine are reviewed. The hypothesis that malignant stem cells evolve from normal stem cells, is considered. Information is being accumulated on the possibility that certain cell populations that can be propagated as cell lines in vitro can produce cells with features of differentiated cells in addition to others that maintain the line and, in some cases may also initiate tumor formation in vivo. Up to the present time, there is evidence to show that cancer stem cells persist in many cell lines. Tyrosine kinase inhibition produces combinations of autophagy and apoptosis in the human erythroleukemia cell line TF-1 hinting at a heterotypic aggregation of cells containing cancer stem cells. Finally, the mechanisms of cancer development, invasion and metastasis are operatively defined. The purpose of this paper is to review some of the salient features of cancer stem cells in support of the proposal that research in neoplasia be increased. Rather than presenting details of various studies, we have attempted to indicate general areas in which work has been done or is in progress. It is hoped that this survey of the subject will demonstrate a variety of opportunities for additional research in human neoplasia.