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1.
Leukemia ; 29(7): 1485-95, 2015 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-25736236

RESUMO

In this study, we investigated the role of inositol polyphosphate-4-phosphatase, type-II (INPP4B) in acute myeloid leukemia (AML). We observed that AML patients with high levels of INPP4B (INPP4B(high)) had poor response to induction therapy, shorter event-free survival and shorter overall survival. Multivariate analyses demonstrated that INPP4B(high) was an independent predictor of poor prognosis, significantly improving current predictive models, where it outperformed conventional biomarkers including FLT3-ITD and NPM1. Furthermore, INPP4B(high) effectively segregated relative risk in AML patients with normal cytogenetics. The role of INPP4B on the biology of leukemic cells was assessed in vitro. Overexpression of INPP4B in AML cell lines enhanced colony formation potential, recapitulated the chemotherapy resistance observed in AML patients and promoted proliferation in a phosphatase-dependent, and Akt-independent manner. These findings reveal that INPP4B(high) has an unexpected role consistent with oncogenesis in AML, in contrast to its previously reported tumor-suppressive role in epithelial cancers. Overall, we propose that INPP4B is a novel prognostic biomarker in AML that has potential to be translated into clinical practice both as a disease marker and therapeutic target.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Resistencia a Medicamentos Antineoplásicos , Leucemia Mieloide Aguda/metabolismo , Leucemia Mieloide Aguda/terapia , Monoéster Fosfórico Hidrolases/metabolismo , Tirosina Quinase 3 Semelhante a fms/metabolismo , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Apoptose/efeitos dos fármacos , Apoptose/efeitos da radiação , Western Blotting , Proliferação de Células/efeitos dos fármacos , Proliferação de Células/efeitos da radiação , Quimiorradioterapia , Citarabina/administração & dosagem , Daunorrubicina/administração & dosagem , Feminino , Imunofluorescência , Seguimentos , Humanos , Técnicas Imunoenzimáticas , Leucemia Mieloide Aguda/mortalidade , Leucemia Mieloide Aguda/patologia , Masculino , Pessoa de Meia-Idade , Mutação/genética , Estadiamento de Neoplasias , Nucleofosmina , Monoéster Fosfórico Hidrolases/genética , Prognóstico , RNA Mensageiro/genética , Radiação Ionizante , Reação em Cadeia da Polimerase em Tempo Real , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Taxa de Sobrevida , Sequências de Repetição em Tandem/genética , Células Tumorais Cultivadas , Adulto Jovem , Tirosina Quinase 3 Semelhante a fms/genética
2.
Bone Marrow Transplant ; 48(8): 1040-5, 2013 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-23396407

RESUMO

Success of umbilical cord blood transplantation (UCBT) has been limited by a high rate of graft failure and delayed hematological recovery. It has been postulated that MSCs have hematopoiesis-supportive properties. Therefore, to overcome the limitation of UCBT, third-party UCB-derived MSCs were co-transplanted in recipients receiving unrelated UCBT. Seven patients received UCB and third-party UCB-MSCs. Hematopoietic recovery and transplantation outcomes were compared with historic controls. There was no acute toxicity associated with the infusion of MSCs. The median day to neutrophil engraftment was 19 days in patients, as compared with 24 days in controls (P=0.03). The median day of platelet engraftment was 47 days and 57 days in patients and controls, respectively (P=0.26). In addition, there was no engraftment failure in the MSC group. The incidence of acute and chronic GVHD was comparable between the two groups. However, veno-occlusive disease and TRM did not occur in the MSC group. Third-party UCB-MSCs infusion was safe and feasible. MSCs may also enhance the engraftment of UCBT and prevent rejection. In addition, MSCs may have a role in decreasing TRM. Randomized, controlled trials are required to confirm these results and longer follow-up will determine the effects of MSCs on the risk of relapse.


Assuntos
Transplante de Células-Tronco de Sangue do Cordão Umbilical/métodos , Transplante de Células-Tronco Mesenquimais/métodos , Doença Aguda , Estudos de Casos e Controles , Criança , Pré-Escolar , Transplante de Células-Tronco de Sangue do Cordão Umbilical/efeitos adversos , Feminino , Rejeição de Enxerto/prevenção & controle , Sobrevivência de Enxerto , Doença Enxerto-Hospedeiro/etiologia , Doença Enxerto-Hospedeiro/prevenção & controle , Humanos , Leucemia/cirurgia , Masculino , Transplante de Células-Tronco Mesenquimais/efeitos adversos , Resultado do Tratamento
3.
Bone Marrow Transplant ; 48(1): 68-73, 2013 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-22635247

RESUMO

From January 2004 to December 2008, 50 consecutive patients with high-risk neuroblastoma were assigned to receive tandem HDCT (high-dose chemotherapy)/auto-SCT after nine cycles of induction chemotherapy. CEC (carboplatin + etoposide + cyclophosphamide) regimen and TM (thiotepa + melphalan)-TBI regimen (or TM regimen for stage 3 patients) were the first and second HDCT regimens. Local radiotherapy, differentiation therapy with 13-cis-retinoid acid and immunotherapy with interleukin-2 were given after tandem HDCT/auto-SCT. Of the 50 patients, 49 underwent a first HDCT/auto-SCT and 47 underwent a second HDCT/auto-SCT. The tumor relapsed or progressed in 14 patients, secondary malignancy developed in one patient and one patient died from chronic lung disease. Therefore, 34 patients remained event free with a median follow-up of 54.5 months (range, 14-94 months) from diagnosis. The probabilities of 5-year OS and EFS for all 50 patients were 77.0% (95% confidence interval (CI), 63.7-90.3) and 71.4% (95% CI, 58.7-84.1), respectively. However, all patients who remained event free for >3 years after tandem HDCT/auto-SCT experienced late adverse effects. Chemotherapeutic dose-escalation strategy using tandem HDCT/auto-SCT was very encouraging for survival. However, further studies incorporating newer treatment modalities are needed to reduce late adverse effects without jeopardizing the survival rate.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Quimioterapia de Indução , Neuroblastoma/terapia , Radioterapia/métodos , Transplante de Células-Tronco , Antineoplásicos/administração & dosagem , Antineoplásicos/efeitos adversos , Antineoplásicos/uso terapêutico , Protocolos de Quimioterapia Combinada Antineoplásica/administração & dosagem , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Neoplasias Ósseas/diagnóstico , Neoplasias Ósseas/patologia , Neoplasias Ósseas/secundário , Neoplasias Ósseas/terapia , Criança , Pré-Escolar , Terapia Combinada/efeitos adversos , Variações do Número de Cópias de DNA , Estudos de Viabilidade , Humanos , Quimioterapia de Indução/efeitos adversos , Lactente , Interleucina-2/administração & dosagem , Interleucina-2/efeitos adversos , Interleucina-2/uso terapêutico , Isotretinoína/administração & dosagem , Isotretinoína/efeitos adversos , Isotretinoína/uso terapêutico , Proteína Proto-Oncogênica N-Myc , Proteínas de Neoplasias/genética , Proteínas de Neoplasias/metabolismo , Estadiamento de Neoplasias , Neuroblastoma/diagnóstico , Neuroblastoma/patologia , Neuroblastoma/secundário , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Proteínas Oncogênicas/genética , Proteínas Oncogênicas/metabolismo , Prognóstico , Estudos Prospectivos , Radioterapia/efeitos adversos , Transplante de Células-Tronco/efeitos adversos , Análise de Sobrevida , Transplante Autólogo , Irradiação Corporal Total/efeitos adversos
4.
Int J Obes (Lond) ; 34(3): 547-56, 2010 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-20029379

RESUMO

OBJECTIVE: To investigate whether drugs targeting peripheral cannabinoid-1 (CB1) receptor ameliorate adiposity comparable to central CB1-receptor antagonist or not. MEASUREMENTS: Receptor binding assay and functional assay in vitro. Pharmacokinetic parameters in mice, brain uptake clearance of compounds in rats and antagonism on the CB1-agonist-induced hypothermia in mice. Diet consumption, body weight changes, hepatic gene expression of sterol-regulatory element-binding protein-1 (SREBP-1) and plasma/tissue concentrations of compounds in HF diet-induced obese (HF-DIO) mice after acute and chronic treatment. RESULTS: Compound-1, an SR141716A derivative, is a peripheral CB1-receptor-selective antagonist that is 10 times less potent than SR141716A in in vitro evaluations. Although the plasma concentrations of Compound-1 are five times higher than those of SR141716A, its potency is still 10 times lower than that of SR141716A in reducing the consumption of normal or HF diet by mice. Through evaluations of brain uptake and the effect on CB1-agonist-induced hypothermia, it was verified that the blood-brain barrier (BBB) penetration of Compound-1 is much lower than that of SR141716A. In HF-DIO mice, chronic treatment by Compound-1 showed dose-dependent antiobesity activities, while its brain distribution was very low as compared with that of SR141716A. Compound-1's effective doses for antiobesity activity were just over 30 mg kg(-1). However, Compound-1 completely suppressed the elevated hepatic SREBP-1 expression even at 10 mg kg(-1). CONCLUSION: These results suggest that (1) central CB1 receptors mediate anorectic response of CB1-receptor antagonists and (2) peripheral modulations, including SREBP-1 expression, are not major mechanisms in the antiobesity effects of CB1-receptor antagonists.


Assuntos
Adiposidade/efeitos dos fármacos , Comportamento Alimentar/efeitos dos fármacos , Obesidade/tratamento farmacológico , Pirazóis/farmacologia , Receptor CB1 de Canabinoide/antagonistas & inibidores , Adiposidade/fisiologia , Animais , Benzoxazinas/antagonistas & inibidores , Benzoxazinas/farmacocinética , Benzoxazinas/farmacologia , Encéfalo/metabolismo , Cricetinae , Cricetulus , Relação Dose-Resposta a Droga , Comportamento Alimentar/fisiologia , Hipotermia/induzido quimicamente , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Morfolinas/antagonistas & inibidores , Morfolinas/farmacocinética , Morfolinas/farmacologia , Naftalenos/antagonistas & inibidores , Naftalenos/farmacocinética , Naftalenos/farmacologia , Obesidade/metabolismo , Piperidinas/farmacocinética , Piperidinas/farmacologia , Pirazóis/sangue , Pirazóis/farmacocinética , Ratos , Ratos Sprague-Dawley , Receptor CB1 de Canabinoide/agonistas , Rimonabanto , Proteína de Ligação a Elemento Regulador de Esterol 1/metabolismo , Distribuição Tecidual
5.
Nanotechnology ; 19(10): 105305, 2008 Mar 12.
Artigo em Inglês | MEDLINE | ID: mdl-21817698

RESUMO

We demonstrate a hybrid process for fabricating one-dimensional wire devices. The process is a combination of an alignment procedure using dielectrophoresis and subsequent contact metal formation utilizing electrochemical deposition with non-toxic organic-based Au electrolytes. Several devices have been successfully made from GaN nanowires or multi-walled carbon nanotubes (MWCNTs) using our hybrid technique. We demonstrate that rapid thermal annealing improves the ohmic characteristics by five orders of magnitude in the case of the GaN devices and ∼300% in the case of the MWCNT devices. One of the reasons for this improvement is enhanced gold wetting due to the reduction of grain size at the annealing temperature.

6.
J Pharmacol Exp Ther ; 318(2): 555-62, 2006 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-16699068

RESUMO

Human cathepsin K, a cysteine proteinase of the papain family, has been recognized as a potential drug target for the treatment of osteoporosis. The predominant expression of cathepsin K in osteoclasts has rendered the enzyme into a major target for the development of novel antiresorptive drugs. Now, we report the pharmacological properties of OST-4077 [furan-2-carboxylic acid (1-{1-[4-fluoro-2-(2-oxo-pyrrolidin-1-yl)-phenyl]-3-oxo-piperidin-4-ylcarbamoyl}-cyclohexyl)-amide] as a novel selective cathepsin K inhibitor. Human and rat cathepsin K were inhibited in vitro by OST-4077 with the IC50 values of 11 and 427 nM, respectively. OST-4077 suppressed bone resorption induced by rabbit osteoclasts (IC50, 37 nM) but did not affect bone mineralization or cellular alkaline phosphatase activity in MC3T3-E1 cells. Parathyroid hormone-induced bone resorption was inhibited in a dose-dependent manner in thyroparathyroidectomized rats gavaged with a single dose of OST-4077 (ED50, 69 mg/kg). When given orally twice daily for 4 weeks to 3-month-old ovariectomized (OVX) rats, OST-4077 dose-dependently prevented bone loss, as monitored by bone densitometry, ash content, and urinary excretion of deoxypyridinoline. No change in serum osteocalcin in the OVX rats by OST-4077 suggested that bone formation might not be affected by the agent. In summary, OST-4077 selectively inhibited bone resorbing activities of osteoclasts and prevented bone loss induced by estrogen deficiency but did not affect bone formation. OST-4077, an orally active selective human cathepsin K inhibitor, may have the therapeutic potential for the treatment of diseases characterized by excessive bone loss including osteoporosis.


Assuntos
Amidas/farmacologia , Amidas/uso terapêutico , Conservadores da Densidade Óssea/farmacologia , Conservadores da Densidade Óssea/uso terapêutico , Reabsorção Óssea/tratamento farmacológico , Catepsinas/antagonistas & inibidores , Inibidores Enzimáticos/farmacologia , Inibidores Enzimáticos/uso terapêutico , Furanos/farmacologia , Furanos/uso terapêutico , Osteoclastos/efeitos dos fármacos , Fosfatase Alcalina/metabolismo , Animais , Biomarcadores , Densidade Óssea/efeitos dos fármacos , Reabsorção Óssea/metabolismo , Catepsina K , Catepsinas/genética , Clonagem Molecular , Estrogênios/deficiência , Feminino , Humanos , Ovariectomia , Hormônio Paratireóideo/farmacologia , Coelhos , Ratos , Ratos Sprague-Dawley
7.
Allergy ; 58(7): 585-8, 2003 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-12823115

RESUMO

BACKGROUND: There has been an increase in allergic diseases as a result of increased air pollution emanating from traffic and various industries. OBJECTIVE: This study evaluated the association between air pollution and airway hyperresponsiveness in a cross-sectional study of a cohort of 670 children, aged 10-13 years. METHODS: We measured spirometry and conducted allergic skin tests and methacholine challenge tests in 670 schoolchildren. The methacholine concentration causing a 20% fall in FEV1 (PC20) was used as the threshold of airway hyperresponsiveness (AHR). Thresholds of 16 mg/dl or less were assumed to indicate AHR. RESULTS: All of the schoolchildren had normal pulmonary function. Of the children, 257 (38.3%) had AHR. There was a significant increase in AHR in schoolchildren living near a chemical factory [45.0% (138/306), 6.50 +/- 0.48] compared to those in rural [31.9% (52/163), 9.84 +/- 0.83] and coastal [33.3% (67/201), 7.17 +/- 0.68] areas. Atopy was significantly more prevalent near the chemical factory vs the coastal and rural areas [35.6% (109/306) vs 27.3% (55/201) and 23.3% (38/163), respectively, P < 0.007]. Schoolchildren with atopy had lower PC20 than those without atopy (5.98 +/- 0.60 vs 8.15 +/- 0.45, P < 0.001). Positive allergy skin tests and living in a polluted area were risk factors in multivariate analyses adjusted for sex, parents' smoking habits, age, body mass index, nose symptoms and lung symptoms (odds ratio for location = 2.4875, confidence interval 1.6542-3.7406, P < 0.000; odds ratio for allergy skin test = 1.5782, confidence interval 1.1130-2.2379, P < 0.0104). CONCLUSION: Our findings demonstrate that more children living in polluted areas have airway hyperresponsiveness than do those living in less polluted areas.


Assuntos
Poluentes Atmosféricos/efeitos adversos , Exposição Ambiental/efeitos adversos , Exposição por Inalação/efeitos adversos , Hipersensibilidade Respiratória/epidemiologia , Hipersensibilidade Respiratória/etiologia , Adolescente , Alérgenos/efeitos adversos , Criança , Proteção da Criança , Estudos de Coortes , Estudos Transversais , Feminino , Humanos , Coreia (Geográfico)/epidemiologia , Pulmão/efeitos dos fármacos , Pulmão/fisiologia , Masculino , Dióxido de Nitrogênio/efeitos adversos , Prevalência , Hipersensibilidade Respiratória/diagnóstico , Testes Cutâneos , Estatística como Assunto , Dióxido de Enxofre/efeitos adversos
8.
Allergy ; 57(4): 341-5, 2002 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-11906366

RESUMO

BACKGROUND: The balance between the two subsets of T cell is pivotal for allergic sensitization. OBJECTIVE: We conducted a cross-sectional study of 486 children vaccinated with bacillus Calmette-Guérin (BCG), aged 10-13 years, to evaluate whether tuberculin responses may contribute to airway hyperresponsiveness (AHR). METHODS: Tuberculin skin test, allergic skin test, and methacholine challenge test were done. The methacholine concentration causing a 20% fall (PC20) in forced expiratory volume in 1 second (FEV1) was used as a threshold of AHR. Atopy was defined as a reaction showing a mean wheal size of > or = 3 mm to one or more allergens on skin prick test (SPT). Two tuberculin units of polysorbate-stabilized purified protein derivatives (PPD) were injected intradermally into the volar surface of the forearm. Reactions were read at 48-72 h as the transverse diameter in millimeters of induration. RESULTS: Of the children in the study, 12.3% (60/486) had PPD induration; 7.8% (38/486) of children had PPD induration of greater than 10 mm. The PPD induration size was 10.5 +/- 1.03 mm (confidence interval (CI) 7.19-12.33) in atopic children and 11.2 +/- 0.76 mm (CI 7.89-13.1) in nonatopic children. The differences of PPD induration diameter between the two groups were not significant. There was no difference of log PC20 between PPD induration > or = 10 mm and < 10 mm (0.13 +/- 0.18 vs. 0.42 +/- 0.05). The difference of log PC20 between positive and negative tuberculin response was not significant. Children with atopy had lower log PC20 than those without atopy (0.16 +/- 0.07 vs. 0.51 +/- 0.05, P = 0.001). After adjusting for sex, age, height, weight, tuberculin response, atopy was associated with AHR in multivariate analyses (odds ratio = 1.895, CI 1.285-2.505, P = 0.002). CONCLUSION: These data suggested that a tuberculin response due to mycobacterial infection status have no effect on AHR in schoolchildren.


Assuntos
Hiper-Reatividade Brônquica/fisiopatologia , Tuberculina/imunologia , Adolescente , Vacina BCG/uso terapêutico , Hiper-Reatividade Brônquica/tratamento farmacológico , Criança , Proteção da Criança , Estudos Transversais , Relação Dose-Resposta Imunológica , Feminino , Humanos , Coreia (Geográfico)/epidemiologia , Masculino , Análise Multivariada , Testes Cutâneos , Tuberculina/efeitos dos fármacos
9.
Biochem Pharmacol ; 62(10): 1379-90, 2001 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-11709198

RESUMO

The mechanisms of cadmium-induced toxicity may include oxidative stress, altered redox homeostasis, and injuries to organelles. The current study was designed to study the effect of decreased cellular glutathione (GSH) content by sulfur amino acid deprivation on cadmium toxicity and to identify the signaling pathways responsible for the cytotoxicity. GSH content was increased by cadmium in H4IIE cells prior to cell death, which was prevented by excess GSH or cysteine. Cell viability, however, was not improved by GSH or cysteine complexation of cadmium. Cadmium-induced cytotoxicity was 40-fold potentiated in cells with decreased GSH by sulfur amino acid deprivation. Cadmium in combination with decreased GSH markedly increased apoptotic cell death. Mitogen-activated protein kinases including extracellular signal-regulated kinase 1/2, p38 kinase and c-Jun N-terminal kinase (JNK) were all activated 1-12 hr after sulfur amino acid deprivation. U0126 (1,4-diamino-2,3-dicyano-1,4-bis[2-aminophenylthio]butadiene), which inhibited activation of extracellular signal-regulated kinase1/2 and p38 kinase in cells under sulfur amino acid deprivation, completely prevented potentiation in Cd-induced cytotoxicity and apoptosis. Potentiation of cadmium toxicity by sulfur amino acid deprivation was prevented in part by either PD98059 or SB203580, or in cells stably expressing dominant negative mutant of JNK1, and to greater extents by PD98059 in combination with either SB203580 or JNK1(-) transfection. These results demonstrated that decreased cellular GSH content potentiated cytotoxicity induced by cadmium at the level of human exposure, and that the potentiation of cytotoxicity resulted from activation of extracellular signal-regulated kinase1/2 in conjunction with p38 kinase or JNK.


Assuntos
Aminoácidos Sulfúricos/metabolismo , Butadienos/farmacologia , Cádmio/farmacologia , Inibidores Enzimáticos/farmacologia , Proteínas Quinases Ativadas por Mitógeno/antagonistas & inibidores , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Nitrilas/farmacologia , Aminoácidos/metabolismo , Animais , Cisteína/metabolismo , Sinergismo Farmacológico , Ativação Enzimática/efeitos dos fármacos , Flavonoides/farmacologia , Glutationa/metabolismo , Proteínas Quinases JNK Ativadas por Mitógeno , Ratos , Células Tumorais Cultivadas , Proteínas Quinases p38 Ativadas por Mitógeno
10.
Cancer Chemother Pharmacol ; 47(6): 511-8, 2001 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-11459204

RESUMO

PURPOSE: DA-125 [(8S,10S)-8-(3-Aminopropanoyloxyacetyl)-10-[(2,6-dideoxy-2-fluoro-alpha-L-talopyranosyl) oxy]-7,8,9,10-tetrahydro-6,8,11-trihydroxy-1-methoxy-5,12-naphthacene-dione hydrochloride] is a novel anthracycline derivative with anticancer activity. In the present study, we compared the cytotoxicity of DA-125 with that of doxorubicin in H4IIE rat hepatoma cells and investigated the mechanistic basis. Because activation of MAP kinases, in particular c-Jun N-terminal kinase (JNK), is implicated in apoptotic cell death, the signaling pathways responsible for DA-125-induced apoptosis were studied. METHODS: Cytotoxicity and apoptosis were measured in H4IIE cells and cells were stably transfected with a dominant-negative mutant of JNK1 (JNK1-) by MTT and TUNEL assays. Inhibition of topoisomerase II activity was determined in vitro. Drug accumulation and DNA binding affinity were determined by fluorescence spectroscopy. RESULTS: The cytotoxicity of DA-125 was greater than that of doxorubicin (IC50 11.5 vs 70 microM). DA-125 induced apoptosis with 30-fold greater potency than doxorubicin. Inhibition of topoisomerase II by DA-125 was fourfold greater. The presence of excess beta-alanine, a DA-125 moiety, failed to alter cytotoxicity and accumulation of DA-125, indicating that the improved cytotoxicity of DA-125 did not result from the beta-alanine moiety. Greater cellular accumulation of DA-125 correlated with its high-affinity DNA binding. Although neither PD98059 nor SB203580 altered the degree of cytotoxicity induced by DA-125, JNK1 cells exhibited about a twofold greater viability than control cells. DA-125-induced apoptosis was also decreased in JNK1- -transfected cells. CONCLUSIONS: DA-125 potently inhibited topoisomerase II activity and induced apoptosis by a high rate of prooxidant production. DA-125 exhibited high-affinity DNA binding with improved cellular drug accumulation. Apoptosis induced by DA-125 involved the pathway of JNK1, but not ERK1/2 or p38 kinase.


Assuntos
Antineoplásicos/farmacologia , DNA de Neoplasias/metabolismo , Doxorrubicina/farmacologia , Inibidores Enzimáticos/farmacologia , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Inibidores da Topoisomerase II , Animais , Antineoplásicos/metabolismo , Carcinoma Hepatocelular/tratamento farmacológico , Carcinoma Hepatocelular/metabolismo , Doxorrubicina/análogos & derivados , Doxorrubicina/metabolismo , Proteínas Quinases JNK Ativadas por Mitógeno , Neoplasias Hepáticas/tratamento farmacológico , Neoplasias Hepáticas/metabolismo , Peroxidase/metabolismo , Ratos , Células Tumorais Cultivadas , beta-Alanina/metabolismo
11.
Toxicol Lett ; 121(1): 45-55, 2001 Apr 08.
Artigo em Inglês | MEDLINE | ID: mdl-11312036

RESUMO

Sulfur amino acid deficiency occurs in certain pathophysiological situations (e.g. protein-calorie malnutrition). Previous studies revealed that sulfur amino acid deprivation (SAAD) activated MAP kinases and potentiated cadmium-induced cytotoxicity by activation of ERK1/2 in conjunction with p38 kinase or JNK. The present study was designed to determine susceptibility of cells to a variety of heavy metals in combination with SAAD. Viability was assessed in H4IIE cells treated with sodium arsenite, mercuric chloride, sodium selenite, lead acetate, chromium trioxide or manganese chloride. SAAD potentiated the cytotoxicity of H4IIE cells by arsenic or mercury (i.e. EC50, 19 and 5 microM in SAAD vs. 401 and 42 microM in control medium, respectively). TUNEL assays revealed that the potentiated arsenic or mercury toxicity involved apoptotic cell death. Lead or selenite moderately elicited cell death, which was not enhanced by SAAD. Chromium or manganese caused no significant cytotoxicity. Treatment of cells with U0126 [1,4-diamino-2,3-dicyano-1,4-bis(2-aminophenylthio)butadiene] an ERK1/2 inhibitor or SB203580 [4-(4-fluorophenyl)-2-(4-methylsulfinylphenyl)-5-(4-pyridyl)1H-imidazole] a p38 kinase inhibitor effectively prevented SAAD-potentiated arsenic toxicity. The potentiated arsenic toxicity was also inhibited in cells stably expressing a dominant negative mutant of c-Jun N-terminal kinase 1 [JNK1(-)]. The inhibitors of extracellular signal-regulated kinase 1/2 (ERK1/2) and p38 kinase failed to prevent mercury-induced toxicity enhanced by SAAD. JNK1(-) cells were minimally susceptible to mercury in SAAD medium. These results demonstrated that SAAD potentiated cytotoxicity induced by arsenic or mercury and that activation of ERK1/2, p38 kinase and JNK1 was responsible for the potentiated arsenic toxicity, whereas the mercury toxicity enhanced by SAAD was mediated with the activity of JNK1.


Assuntos
Aminoácidos Sulfúricos/deficiência , Arsênio/toxicidade , Mercúrio/toxicidade , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Venenos/toxicidade , Animais , Sobrevivência Celular/efeitos dos fármacos , Ativação Enzimática/efeitos dos fármacos , Marcação In Situ das Extremidades Cortadas , Proteína Quinase 8 Ativada por Mitógeno , Ratos , Transdução de Sinais/efeitos dos fármacos , Sais de Tetrazólio , Tiazóis , Células Tumorais Cultivadas , Proteínas Quinases p38 Ativadas por Mitógeno
12.
Chem Biol Interact ; 127(1): 13-28, 2000 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-10903416

RESUMO

Growth hormone and insulin are the primary determinants for cytochrome P450 2E1 (CYP2E1) expression. The role of glucose on the induction of CYP2E1 by hypophysectomy and on the restorative effect by growth hormone was investigated in the rat liver. Western and Northern blot analyses revealed that hypophysectomy induced CYP2E1 by 5-fold at 1-4 weeks, relative to control, with a concomitant increase in CYP2E1 mRNA. Hypophysectomized rats (HXR) showed a 20% reduction in the plasma glucose level. Hypophysectomy-induced increase in the CYP2E1 mRNA was completely abolished by glucose feeding in drinking water (10%) for 7 days. Treatment of HXR with hGH (2 I.U./kg, twice a day, for 7 days) inhibited the increases in CYP2E1 protein and mRNA levels with restoration of the plasma glucose level. In contrast to the effect of human growth hormone (hGH) on CYP2E1 in HXR with free access to foods, CYP2E1 expression failed to be restored by hGH in starving HXR. However, glucose feeding of starving HXR abolished the induction of CYP2E1. Effects of hypophysectomy and hGH treatment were studied in streptozotocin-induced diabetic rats. Insulin, but not hGH, prevented an increase in CYP2E1 mRNA in diabetic rats. The hepatic CYP2E1 induction in hypophysectomized diabetic rats was inhibited by hGH treatment, indicating that the hGH effect on CYP2E1 expression did not involve insulin production. These results provide evidence that the induction of hepatic CYP2E1 by hypophysectomy may result from reduced glucose utilization, and that the effect of hGH on CYP2E1 expression may be mediated with enhanced glucose utilization, but not with insulin production.


Assuntos
Citocromo P-450 CYP2E1/biossíntese , Glucose/metabolismo , Hormônio do Crescimento Humano/farmacologia , Hipofisectomia , Fígado/enzimologia , Animais , Glicemia/metabolismo , Citocromo P-450 CYP2E1/genética , Indução Enzimática/efeitos dos fármacos , Expressão Gênica/efeitos dos fármacos , Glucose/administração & dosagem , Humanos , Masculino , RNA Mensageiro/metabolismo , Ratos , Ratos Sprague-Dawley , Inanição
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