Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 16 de 16
Filtrar
1.
Bioorg Med Chem Lett ; 28(3): 240-243, 2018 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-29317167

RESUMO

Panax ginseng as a traditional Chinese medicine has been extensively used for the treatment of many diseases, especially in prolonging life and anti-tumor. Dammarane-type triterpenoids from P. ginseng have diverse beneficial effects and their chemical structures can be modified in the gastrointestinal tract after oral administration. In this paper, the dammarane-type triterpenoids were isolated from artificial gastric juice incubate of total saponins in the stems and leaves of P. ginseng through column chromatographic methods and their chemical structures were determined based on spectral data. Two new dammarane-type triterpenoids named ginsenotransmetins B (1) and C (2), along with twenty-nine known compounds (3-31), were obtained. All 31 compounds isolated were investigated for their activities of SIRT1 using SIRT1 fluorometric drug discovery assay kit. Among them, compounds 11, 17, 18, 20, 23, 24, 28, and 29, which were found to be potential as SIRT1 activators, exhibited significant stimulation of SIRT1 activity. The results showed that these compounds may be considered to be a useful medicinal resource for prolonging life and anti-tumor. In addition, the results were helpful to explain the longevity effect of ginseng from the new field of view.


Assuntos
Ativadores de Enzimas/química , Panax/química , Saponinas/química , Sirtuína 1/química , Triterpenos/química , Ativadores de Enzimas/isolamento & purificação , Folhas de Planta/química , Caules de Planta/química , Saponinas/isolamento & purificação , Estereoisomerismo , Triterpenos/isolamento & purificação
2.
Molecules ; 21(6)2016 Jun 10.
Artigo em Inglês | MEDLINE | ID: mdl-27294899

RESUMO

20(S)-Ginsenoside Rg2 (1) has recently become a hot research topic due to its potent bioactivities and abundance in natural sources such as the roots, rhizomes and stems-leaves of Panax ginseng. However, due to the lack of studies on systematic metabolic profiles, the prospects for new drug development of 1 are still difficult to predict, which has become a huge obstacle for its safe clinical use. To solve this problem, investigation of the metabolic profiles of 1 in rat liver microsomes was first carried out. To identify metabolites, a strategy of combined analyses based on prepared metabolites by column chromatography and ultra-performance liquid chromatography coupled with quadrupole time-of-flight tandem mass spectrometry (UPLC-Q-TOF/MS) was performed. As a result, four metabolites M1-M4, including a rare new compound named ginsenotransmetin A (M1), were isolated and the structures were confirmed by spectroscopic analyses. A series of metabolites of 1, MA-MG, were also tentatively identified by UPLC-Q-TOF/MS in rat liver microsomal incubate of 1. Partial metabolic pathways were proposed. Among them, 1 and its metabolites M1, M3 and M4 were discovered for the first time to be activators of SIRT1. The SIRT1 activating effects of the metabolite M1 was comparable to those of 1, while the most interesting SIRT1 activatory effects of M3 and M4 were higher than that of 1 and comparable with that of resveratrol, a positive SIRT1 activator. These results indicate that microsome-dependent metabolism may represent a bioactivation pathway for 1. This study is the first to report the metabolic profiles of 1 in vitro, and the results provide an experimental foundation to better understand the in vivo metabolic fate of 1.


Assuntos
Ginsenosídeos/metabolismo , Microssomos Hepáticos/efeitos dos fármacos , Panax/metabolismo , Sirtuína 1/biossíntese , Animais , Cromatografia Líquida , Ginsenosídeos/química , Ginsenosídeos/uso terapêutico , Redes e Vias Metabólicas/efeitos dos fármacos , Microssomos Hepáticos/metabolismo , Panax/química , Ratos , Sirtuína 1/genética , Espectrometria de Massas em Tandem
3.
Bioorg Med Chem Lett ; 25(22): 5321-5, 2015 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-26420067

RESUMO

Two new dammarane-type triterpenes, namely ginsenoslaloside-I [3ß,12ß,24S-trihydroxy-dammara-20(22)E,25-diene-3-O-ß-D-glucopyranoside, 1] and 20(S)-ginsenoside-Rh1-6'-acetate (2), together with twelve known compounds (3-14) were isolated from the alkaline hydrolysate of total saponins of the stems-leaves of Panax ginseng C.A. Meyer. Their chemical structures were elucidated by extensive spectroscopic analyses and comparison with the reported data. All 14 compounds were evaluated for their anti-proliferative activities against two human cancer cell lines (HL-60 and Hep-G2) and promotion activities of SIRT1. Compound 6 exhibited significant inhibitory activity in a concentration-dependent manner against HL-60 and Hep-G2 with the IC50 values of 10.32 and 24.33µM, respectively, and had comparable IC50 values with those of vinorelbine, a positive control agent. Meanwhile, compounds 1 and 6 were found to be a potential activator of SIRT1. The preliminary structure-activity relationship was also discussed based on the experimental data obtained.


Assuntos
Antineoplásicos Fitogênicos/farmacologia , Ginsenosídeos/química , Panax/química , Folhas de Planta/química , Caules de Planta/química , Saponinas/química , Sirtuína 1/metabolismo , Antineoplásicos Fitogênicos/química , Proliferação de Células/efeitos dos fármacos , Ativação Enzimática/efeitos dos fármacos , Ginsenosídeos/farmacologia , Células HL-60 , Células Hep G2 , Humanos , Concentração Inibidora 50 , Espectroscopia de Ressonância Magnética , Estrutura Molecular , Neoplasias/tratamento farmacológico , Hidrolisados de Proteína/química
4.
Molecules ; 20(12): 21597-608, 2015 Dec 03.
Artigo em Inglês | MEDLINE | ID: mdl-26633350

RESUMO

A high-performance liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) method was successfully developed and validated for the identification and determination of eight ginsenosides: ginsenoside Rg1 (1); 20(S)-ginsenoside Rh1 (2); 20(S)-ginsenoside Rg2 (3); 20(R)-ginsenoside Rh1 (4); 20(R)-ginsenoside Rg2 (5); ginsenoside Rd (6); 20(S)-ginsenoside Rg3 (7); and 20(R)-ginsenoside Rg3 (8) in rat plasma. The established rapid method had high linearity, selectivity, sensitivity, accuracy, and precision. The method has been used successfully to study the pharmacokinetics of abovementioned eight ginsenosides for the first time. After an oral administration of total saponins in the stems-leaves of Panax ginseng C. A. Meyer (GTSSL) at a dose of 400 mg/kg, the ginsenosides 6, 7, and 8, belonging to protopanaxadiol-type saponins, exhibited relatively long tmax values, suggesting that they were slowly absorbed, while the ginsenosides 1-5, belonging to protopanaxatriol-type saponins, had different tmax values, which should be due to their differences in the substituted groups. Compounds 2 and 4, 3 and 5, 7 and 8 were three pairs of R/S epimerics at C-20, which was interesting that the t1/2 of 20(S)-epimers were always longer than those of 20(R)-epimers. This pharmacokinetic identification of multiple ginsenosides of GTSSL in rat plasma provides a significant basis for better understanding the clinical application of GTSSL.


Assuntos
Cromatografia Líquida/métodos , Ginsenosídeos/sangue , Ginsenosídeos/farmacocinética , Plasma/química , Espectrometria de Massas por Ionização por Electrospray/métodos , Animais , Masculino , Ratos , Ratos Sprague-Dawley , Distribuição Tecidual
5.
Blood ; 119(12): 2873-82, 2012 Mar 22.
Artigo em Inglês | MEDLINE | ID: mdl-22318203

RESUMO

The BCR-ABL fusion protein generated by t(9;22)(q34;q11) in chronic myeloid leukemia (CML) plays an essential role in the pathogenesis of the myeloproliferative disorder status at the chronic phase of the disease, but progression from the chronic phase to blast crisis (BC) is believed to require additional mutations. To explore the underlying mechanisms for BC, which is characterized by a blockage of blood cell differentiation, we screened several genes crucial to hematopoiesis and identified 10 types of mutations in RUNX1 among 11 of 85 (12.9%) patients with acute transformation of CML. Most of the mutations occurred in the runt homology domain, including H78Q, W79C, R139G, D171G, R174Q, L71fs-ter94, and V91fs-ter94. Further studies indicated that RUNX1 mutants not only exhibited decreased transactivation activity but also had an inhibitory effect on the WT RUNX1. To investigate the leukemogenic effect of mutated RUNX1, H78Q and V91fs-ter94 were transduced into 32D cells or BCR-ABL-harboring murine cells, respectively. Consistent with the myeloblastic features of advanced CML patients with RUNX1 mutations, H78Q and V91fs-ter94 disturbed myeloid differentiation and induced a BC or accelerated phase-like phenotype in mice. These results suggest that RUNX1 abnormalities may promote acute myeloid leukemic transformation in a subset of CML patients.


Assuntos
Crise Blástica/genética , Transformação Celular Neoplásica/genética , Subunidade alfa 2 de Fator de Ligação ao Core/genética , Leucemia Mielogênica Crônica BCR-ABL Positiva/genética , Mutação , Adolescente , Adulto , Animais , Diferenciação Celular/genética , Feminino , Humanos , Imunoprecipitação , Masculino , Camundongos , Pessoa de Meia-Idade , Análise de Sequência com Séries de Oligonucleotídeos , Reação em Cadeia da Polimerase em Tempo Real , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Transfecção , Adulto Jovem
6.
Zhonghua Zhong Liu Za Zhi ; 34(3): 169-75, 2012 Mar.
Artigo em Chinês | MEDLINE | ID: mdl-22780968

RESUMO

OBJECTIVE: To investigate the underlying mechanism and clinical significance of PU.1 down-expression in chronic myeloid leukemia (CML) patients. METHODS: Different methylation status of PU.1 promoter region containing 20 CpG islands in normal individuals, CML chronic phase and blast crisis patients, complete cytogenetic remission patients after imatinib treatment, and blast crisis bone marrow K562 CML cells was detected by bisulfite sequencing. Semi-quantitative PCR was used to detect the PU.1 mRNA expression in normal controls, CML chronic phase and blast crisis patients, and blast crisis bone marrow K562 CML cells. Indirect immune fluorescence and Western blot were used to analyze the exprtession of PU.1 protein in normal individuals, CML chronic phase and blast crisis patients, and blast crisis bone marrow K562 CML cells. RESULTS: Aberrant methylation in the promoter region of transcription factor PU.1 was found in both CML chronic phase and blast crisis phase bone marrow cells, as well as in CML blast K562 cells. Down-expression of PU.1 mRNA and protein levels was found in above cells. No methylation in the promoter region of PU.1 was observed in normal individuals, and the PU.1 mRNA and protein expressions were not reduced at all. Furthermore, high methylation status of bone marrow cells was even observed in the CML patients who acquired complete cytogenetic remission. CONCLUSIONS: The results of our study indicate that the epigenetic modification of PU.1 in CML patients and K562 cell line might be responsible for the down-expression of PU.1. The data suggest that aberrant methylation of PU.1 plays a role in CML pathogenesis, therefore, it might serve as a useful biomarker and potential target in therapy for chronic myeloid leukemia.


Assuntos
Metilação de DNA , Epigênese Genética , Leucemia Mielogênica Crônica BCR-ABL Positiva/genética , Proteínas Proto-Oncogênicas/genética , Transativadores/genética , Antineoplásicos/uso terapêutico , Benzamidas , Crise Blástica , Células da Medula Óssea/metabolismo , Células da Medula Óssea/patologia , Ilhas de CpG/genética , Regulação para Baixo , Regulação Leucêmica da Expressão Gênica , Humanos , Mesilato de Imatinib , Células K562 , Leucemia Mielogênica Crônica BCR-ABL Positiva/tratamento farmacológico , Leucemia Mielogênica Crônica BCR-ABL Positiva/metabolismo , Piperazinas/uso terapêutico , Regiões Promotoras Genéticas/genética , Proteínas Proto-Oncogênicas/metabolismo , Pirimidinas/uso terapêutico , RNA Mensageiro/metabolismo , Transativadores/metabolismo
7.
Proc Natl Acad Sci U S A ; 105(6): 2076-81, 2008 Feb 12.
Artigo em Inglês | MEDLINE | ID: mdl-18250304

RESUMO

Acquisition of additional genetic and/or epigenetic abnormalities other than the BCR/ABL fusion gene is believed to cause disease progression in chronic myeloid leukemia (CML) from chronic phase to blast crisis (BC). To gain insights into the underlying mechanisms of progression to BC, we screened DNA samples from CML patients during blast transformation for mutations in a number of transcription factor genes that are critical for myeloid-lymphoid development. In 85 cases of CML blast transformation, we identified two new mutations in the coding region of GATA-2, a negative regulator of hematopoietic stem/progenitor cell differentiation. A L359V substitution within zinc finger domain (ZF) 2 of GATA-2 was found in eight cases with myelomonoblastic features, whereas an in-frame deletion of 6 aa (delta341-346) spanning the C-terminal border of ZF1 was detected in one patient at myeloid BC with eosinophilia. Further studies indicated that L359V not only increased transactivation activity of GATA-2 but also enhanced its inhibitory effects on the activity of PU.1, a major regulator of myelopoiesis. Consistent with the myelomonoblastic features of CML transformation with the GATA-2 L359V mutant, transduction of the GATA-2 L359V mutant into HL-60 cells or BCR/ABL-harboring murine cells disturbed myelomonocytic differentiation/proliferation in vitro and in vivo, respectively. These data strongly suggest that GATA-2 mutations may play a role in acute myeloid transformation in a subset of CML patients.


Assuntos
Fator de Transcrição GATA2/genética , Leucemia Mielogênica Crônica BCR-ABL Positiva/genética , Leucemia Mieloide Aguda/genética , Mutação , Animais , Sequência de Bases , Células COS , Linhagem Celular , Chlorocebus aethiops , Primers do DNA , Progressão da Doença , Humanos , Imunoprecipitação , Leucemia Mielogênica Crônica BCR-ABL Positiva/patologia , Leucemia Mieloide Aguda/patologia , Reação em Cadeia da Polimerase Via Transcriptase Reversa
8.
Microbiol Spectr ; 9(1): e0082021, 2021 09 03.
Artigo em Inglês | MEDLINE | ID: mdl-34406837

RESUMO

Karst caves have recently been demonstrated to act as a sink for atmospheric methane, due in part to consumption by microbes residing in caves that can oxidize methane at atmospheric levels. However, our knowledge about the responsible atmospheric methane-oxidizing bacteria (atmMOB) in this vast habitat remains limited to date. To address this issue, weathered rock samples from three karst caves were collected in Guilin City and subjected to high-throughput sequencing of pmoA and 16S rRNA genes. The results showed that members of the high-affinity upland soil cluster (USC), especially upland soil cluster gamma (USCγ), with absolute abundances of 104 to 109 copies · g-1 dry sample, dominated the atmMOB communities, while Proteobacteria and Actinobacteria dominated the overall bacterial communities. Moreover, USCγ was a keystone taxon in cooccurrence networks of both the atmMOB and the total bacterial community, whereas keystone taxa in the bacterial network also included Gaiella and Aciditerrimonas. Positive links overwhelmingly dominated the cooccurrence networks of both atmMOB and the total bacterial community, indicating a consistent response to environmental disturbances. Our study shed new insights on the diversity and abundances underlining atmMOB and total bacterial communities and on microbial interactions in subterranean karst caves, which increased our understanding about USC and supported karst caves as a methane sink. IMPORTANCE Karst caves have recently been demonstrated to be a potential atmospheric methane sink, presumably due to consumption by methane-oxidizing bacteria. However, the sparse knowledge about the diversity, distribution, and community interactions of methanotrophs requires us to seek further understanding of the ecological significance of methane oxidation in these ecosystems. Our pmoA high-throughput results from weathered rock samples from three karst caves in Guilin City confirm the wide occurrence of atmospheric methane-oxidizing bacteria in this habitat, especially those affiliated with the upland soil cluster, with a gene copy number of 104 to 109 copies per gram dry sample. Methanotrophs and the total bacterial communities had more positive than negative interactions with each other as indicated by the cooccurrence network, suggesting their consistent response to environmental disturbance. Our results solidly support caves as an atmospheric methane sink, and they contribute to a comprehensive understanding of the diversity, distribution, and interactions of microbial communities in subsurface karst caves.


Assuntos
Bactérias/isolamento & purificação , Cavernas/microbiologia , Microbiologia do Solo , Bactérias/classificação , Bactérias/genética , Bactérias/metabolismo , DNA Bacteriano/genética , Metano/análise , Metano/metabolismo , Microbiota , Filogenia , RNA Ribossômico 16S/genética
9.
J Int Med Res ; 48(6): 300060520930864, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32543928

RESUMO

Traumatic diaphragmatic rupture (TDR) is an uncommon but life-threatening condition often caused by blunt or penetrating trauma. Symptoms may appear late resulting in delayed or missed diagnosis. We report here a case of a 28-year-old man who presented with left subcostal pain and vomiting after recently binge drinking alcohol. He had experienced bilateral rib fractures two years previously. Computed tomography (CT) showed massive left pleural effusion and pleural fluid drained by thoracentesis had a bloody appearance. The patient developed septic shock but emergency surgery showed no active bleeding. Enhanced-CT showed herniated stomach with ischemic necrosis in the left thoracic cavity. Total gastrectomy and diaphragmatic repair were successful and the patient had an uneventful recovery. A high index of suspicion is necessary when evaluating haemothorax, especially in patients with recent or previous thoraco-abdominal injury.


Assuntos
Diafragma/cirurgia , Hemotórax/complicações , Ruptura/cirurgia , Dor Abdominal/complicações , Adulto , Gastrectomia , Hemotórax/cirurgia , Hérnia Diafragmática Traumática , Humanos , Masculino , Estômago/cirurgia , Traumatismos Torácicos/cirurgia , Tomografia Computadorizada por Raios X , Ferimentos Penetrantes/cirurgia
11.
Zhonghua Xin Xue Guan Bing Za Zhi ; 37(8): 701-7, 2009 Aug.
Artigo em Chinês | MEDLINE | ID: mdl-20021921

RESUMO

OBJECTIVE: To evaluate the effects of amlodipine-based antihypertensive combination regimen on blood pressure control and impact on cardiovascular events. METHODS: From Oct. 2007 to Oct. 2008, a total of 13 542 hypertensive patients from 180 centers in China were included in this multi-centre randomized, controlled, blind-endpoint assessment clinical trial. Inclusion criteria were: essential hypertension, 50 - 79 years of age with at least one cardiovascular risk factor and signed consent forms. Patients were randomly assigned to receive low-dose amlodipine + diuretics (group A) or low-dose amlodipine + telmisartan (group T). The primary endpoints are composite of non-fatal stroke/myocardial infarction and cardiovascular death. All patients will be followed-up for 4 years. RESULTS: The characteristics of patients between the two groups were similar: mean age (61.5 +/- 7.7) Yrs with 19% history of cerebrovascular diseases, 12% coronary diseases, 18% diabetes, 42% dyslipidemia, mean initial blood pressure 157/93 mm Hg. After 8-week treatment, mean blood pressure in group A and B were reduced to (133.0 +/- 11.0)/(81.0 +/- 7.6) mm Hg, (132.9 +/- 11.6)/(80.6 +/- 7.9) mm Hg respectively. Blood pressure control rates reached 72.1% and 72.6% in group A and T, respectively. CONCLUSION: Amlodipine-based antihypertensive combination regimens achieved satisfactory blood pressure control rate in patients with essential hypertension in this patient cohort.


Assuntos
Anlodipino/administração & dosagem , Anti-Hipertensivos/administração & dosagem , Benzimidazóis/administração & dosagem , Benzoatos/administração & dosagem , Hipertensão/tratamento farmacológico , Idoso , Pressão Sanguínea , Quimioterapia Combinada , Feminino , Humanos , Hipertensão/fisiopatologia , Masculino , Pessoa de Meia-Idade , Telmisartan
12.
Int J Hematol ; 102(2): 181-7, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-25997870

RESUMO

Extranodal natural killer/T cell lymphoma, nasal type (ENK/TCL), is an aggressive and rare hematological malignancy. Patients with advanced and relapsed/refractory disease have very poor outcomes. In this study, we retrospectively assessed the efficacy and safety of MEDA regimen (methotrexate, etoposide, dexamethasone and pegaspargase) in the treatment of advanced and relapsed/refractory ENK/TCL patients. Thirteen patients received a total of 55 cycles of MEDA, with a median of four cycles. At the completion of treatment, the overall response rate was 76.9 %, with a complete response rate of 61.5 %. The 1-year overall survival rate was 69.2 %, and 1-year progression-free survival was 61.5 %. Treatment-related toxicity was monitored in all patients. Grade 3/4 neutropenia occurred in 46.2 % of patients. Serious infections happened in two cases (15.4 %). Grade 3/4 thrombocytopenia occurred in 30.8 % of patients, and 23.1 % received platelet transfusion. Grade 3/4 anemia was observed in 23.1 % of patients. Hepatotoxicity and low fibrinogen were common, but mild. These results show that MEDA regimen is very effective with tolerable adverse effects in the treatment of advanced and relapsed/refractory ENK/TCL. Further prospective trials are expected to validate the efficacy of MEDA in an expanded number of patients.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Linfoma Extranodal de Células T-NK/tratamento farmacológico , Linfoma Extranodal de Células T-NK/patologia , Adulto , Idoso , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Asparaginase/administração & dosagem , Dexametasona/administração & dosagem , Etoposídeo/administração & dosagem , Feminino , Humanos , Estimativa de Kaplan-Meier , Linfoma Extranodal de Células T-NK/mortalidade , Linfoma Extranodal de Células T-NK/radioterapia , Masculino , Metotrexato/administração & dosagem , Pessoa de Meia-Idade , Recidiva Local de Neoplasia , Estadiamento de Neoplasias , Polietilenoglicóis/administração & dosagem , Estudos Retrospectivos , Resultado do Tratamento
14.
Artigo em Inglês | MEDLINE | ID: mdl-25314554

RESUMO

In this paper, we investigate nonintegrable semidiscrete Hirota equations, including the nonintegrable semidiscrete Hirota(-) equation and the nonintegrable semidiscrete Hirota(+) equation. We focus on the topics on gauge-equivalent structures and dynamical behaviors for the two nonintegrable semidiscrete equations. By using the concept of the prescribed discrete curvature, we show that, under the discrete gauge transformations, the nonintegrable semidiscrete Hirota(-) equation and the nonintegrable semidiscrete Hirota(+) equation are, respectively, gauge equivalent to the nonintegrable generalized semidiscrete modified Heisenberg ferromagnet equation and the nonintegrable generalized semidiscrete Heisenberg ferromagnet equation. We prove that the two discrete gauge transformations are reversible. We study the dynamical properties for the two nonintegrable semidiscrete Hirota equations. The exact spatial period solutions of the two nonintegrable semidiscrete Hirota equations are obtained through the constructions of period orbits of the stationary discrete Hirota equations. We discuss the topic regarding whether the spatial period property of the solution to the nonintegrable semidiscrete Hirota equation is preserved to that of the corresponding gauge-equivalent nonintegrable semidiscrete equations under the action of discrete gauge transformation. By using the gauge equivalent, we obtain the exact solutions to the nonintegrable generalized semidiscrete modified Heisenberg ferromagnet equation and the nonintegrable generalized semidiscrete Heisenberg ferromagnet equation. We also give the numerical simulations for the stationary discrete Hirota equations. We find that their dynamics are much richer than the ones of stationary discrete nonlinear Schrödinger equations.


Assuntos
Imãs , Modelos Teóricos
15.
Int J Hematol ; 96(1): 65-73, 2012 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-22674382

RESUMO

The PU.1 transcription factor is a crucial regulator of hematopoiesis, and its expression is altered in various leukemic processes. It has been shown that expression of PU.1 is severely impaired in patients with chronic myeloid leukemia (CML), but the mechanism underlying this effect remains unknown. Through bisulfite sequencing, semi-quantitative PCR, and indirect immunofluorescence and Western blot techniques, we found aberrant methylation in the promoter region of transcription factor PU.1 in CML patients both in the chronic and blast crisis phases, as well as in the CML blast K562 cell line. Of these, several CpG sites were more highly methylated in blast crisis than chronic phase, while no methylation of these sites was observed in healthy individuals. Interestingly, CML patients achieved complete cytogenetic remission under imatinib mesylate treatment, but the aberrant methylation status of PU.1 was not reversed. Down-regulation of PU.1 expression at the mRNA and protein levels was also observed in association with aberrant methylation. Thus, for the first time, we have revealed a potential epigenetic modification of PU.1 in CML, which may be responsible for the down-regulation of PU.1. These data suggest that aberrant methylation of PU.1 may play a role in CML pathogenesis, and may therefore serve as a useful biomarker and potential target for demethylating drugs.


Assuntos
Metilação de DNA , Regulação Leucêmica da Expressão Gênica , Leucemia Mielogênica Crônica BCR-ABL Positiva/genética , Proteínas Proto-Oncogênicas/genética , Transativadores/genética , Sequência de Bases , Ilhas de CpG , Regulação para Baixo/genética , Hematopoese/genética , Humanos , Células K562 , Leucemia Mielogênica Crônica BCR-ABL Positiva/metabolismo , Dados de Sequência Molecular , Regiões Promotoras Genéticas , Proteínas Proto-Oncogênicas/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Transativadores/metabolismo
16.
PLoS One ; 4(7): e6257, 2009 Jul 16.
Artigo em Inglês | MEDLINE | ID: mdl-19606213

RESUMO

BACKGROUND: Resistance developed by leukemic cells, unsatisfactory efficacy on patients with chronic myeloid leukemia (CML) at accelerated and blastic phases, and potential cardiotoxity, have been limitations for imatinib mesylate (IM) in treating CML. Whether low dose IM in combination with agents of distinct but related mechanisms could be one of the strategies to overcome these concerns warrants careful investigation. METHODS AND FINDINGS: We tested the therapeutic efficacies as well as adverse effects of low dose IM in combination with proteasome inhibitor, Bortezomib (BOR) or proteasome inhibitor I (PSI), in two CML murine models, and investigated possible mechanisms of action on CML cells. Our results demonstrated that low dose IM in combination with BOR exerted satisfactory efficacy in prolongation of life span and inhibition of tumor growth in mice, and did not cause cardiotoxicity or body weight loss. Consistently, BOR and PSI enhanced IM-induced inhibition of long-term clonogenic activity and short-term cell growth of CML stem/progenitor cells, and potentiated IM-caused inhibition of proliferation and induction of apoptosis of BCR-ABL+ cells. IM/BOR and IM/PSI inhibited Bcl-2, increased cytoplasmic cytochrome C, and activated caspases. While exerting suppressive effects on BCR-ABL, E2F1, and beta-catenin, IM/BOR and IM/PSI inhibited proteasomal degradation of protein phosphatase 2A (PP2A), leading to a re-activation of this important negative regulator of BCR-ABL. In addition, both combination therapties inhibited Bruton's tyrosine kinase via suppression of NFkappaB. CONCLUSION: These data suggest that combined use of tyrosine kinase inhibitor and proteasome inhibitor might be helpful for optimizing CML treatment.


Assuntos
Antineoplásicos/uso terapêutico , Leucemia Mielogênica Crônica BCR-ABL Positiva/tratamento farmacológico , Piperazinas/uso terapêutico , Inibidores de Proteases/uso terapêutico , Inibidores de Proteassoma , Pirimidinas/uso terapêutico , Animais , Benzamidas , Western Blotting , Linhagem Celular Tumoral , Sinergismo Farmacológico , Humanos , Mesilato de Imatinib , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Nus , Interferência de RNA
SELEÇÃO DE REFERÊNCIAS
Detalhe da pesquisa