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1.
Mol Cancer ; 21(1): 172, 2022 08 31.
Artigo em Inglês | MEDLINE | ID: mdl-36045346

RESUMO

BACKGROUND: Anaplastic large cell lymphoma (ALCL) is an aggressive non-Hodgkin T cell lymphoma commonly driven by NPM-ALK. AP-1 transcription factors, cJUN and JUNb, act as downstream effectors of NPM-ALK and transcriptionally regulate PDGFRß. Blocking PDGFRß kinase activity with imatinib effectively reduces tumor burden and prolongs survival, although the downstream molecular mechanisms remain elusive. METHODS AND RESULTS: In a transgenic mouse model that mimics PDGFRß-driven human ALCL in vivo, we identify PDGFRß as a driver of aggressive tumor growth. Mechanistically, PDGFRß induces the pro-survival factor Bcl-xL and the growth-enhancing cytokine IL-10 via STAT5 activation. CRISPR/Cas9 deletion of both STAT5 gene products, STAT5A and STAT5B, results in the significant impairment of cell viability compared to deletion of STAT5A, STAT5B or STAT3 alone. Moreover, combined blockade of STAT3/5 activity with a selective SH2 domain inhibitor, AC-4-130, effectively obstructs tumor development in vivo. CONCLUSIONS: We therefore propose PDGFRß as a novel biomarker and introduce PDGFRß-STAT3/5 signaling as an important axis in aggressive ALCL. Furthermore, we suggest that inhibition of PDGFRß or STAT3/5 improve existing therapies for both previously untreated and relapsed/refractory ALK+ ALCL patients.


Assuntos
Linfoma Anaplásico de Células Grandes , Receptor beta de Fator de Crescimento Derivado de Plaquetas , Fator de Transcrição STAT3 , Fator de Transcrição STAT5 , Quinase do Linfoma Anaplásico , Animais , Carcinogênese/metabolismo , Linhagem Celular Tumoral , Humanos , Linfoma Anaplásico de Células Grandes/genética , Linfoma Anaplásico de Células Grandes/patologia , Camundongos , Fosforilação , Receptor beta de Fator de Crescimento Derivado de Plaquetas/metabolismo , Receptor beta de Fator de Crescimento Derivado de Plaquetas/farmacologia , Fator de Transcrição STAT3/metabolismo , Fator de Transcrição STAT5/genética , Transdução de Sinais
2.
Environ Monit Assess ; 189(5): 241, 2017 May.
Artigo em Inglês | MEDLINE | ID: mdl-28455732

RESUMO

Members of the public in England were invited in 2010 to take part in a national metals survey, by collecting samples of littoral sediment from a standing water body for geochemical analysis. To our knowledge, this is the first national sediment metals survey using public participation and reveals a snapshot of the extent of metals contamination in ponds and lakes across England. Hg, Ni, Cu, Zn and Pb concentrations exceeding sediment quality guidelines for the health of aquatic biota are ubiquitous in ponds and lakes, not just in areas with a legacy of industrial activity. To validate the public sampling approach, a calibration exercise was conducted at ten water bodies selected to represent a range of lakes found across England. Sediment concentrations of Hg, Ni, Cu, Zn and Pb were measured in samples of soil, stream and littoral and deep water sediment to assess inputs. Significant differences between littoral sediment metal concentrations occur due to local variability, but also organic content, especially in upland, peat soil catchments. Variability of metal concentrations between littoral samples is shown to be low in small (<20 ha) lowland lakes. Larger and upland lakes with more complex inputs and variation in organic content of littoral samples have a greater variability. Collection of littoral sediments in small lakes and ponds, with or without voluntary participation, can provide a reliable sampling technique for the preliminary assessment of metal contamination in standing waters. However, the heterogeneity of geology, soils and history/extent of metal contamination in the English landscape, combined with the random nature of sample collection, shows that systematic sampling for evaluating the full extent of metal contamination in lakes is still required.


Assuntos
Participação da Comunidade , Monitoramento Ambiental/métodos , Sedimentos Geológicos/química , Metais/análise , Poluentes Químicos da Água/análise , Biota , Inglaterra , Lagos/química , Mercúrio/análise , Metais Pesados/análise , Inquéritos e Questionários
3.
BMC Ecol ; 16 Suppl 1: 14, 2016 07 22.
Artigo em Inglês | MEDLINE | ID: mdl-27459958

RESUMO

BACKGROUND: Public participation in scientific data collection is a rapidly expanding field. In water quality surveys, the involvement of the public, usually as trained volunteers, generally includes the identification of aquatic invertebrates to a broad taxonomic level. However, quality assurance is often not addressed and remains a key concern for the acceptance of publicly-generated water quality data. The Open Air Laboratories (OPAL) Water Survey, launched in May 2010, aimed to encourage interest and participation in water science by developing a 'low-barrier-to-entry' water quality survey. During 2010, over 3000 participant-selected lakes and ponds were surveyed making this the largest public participation lake and pond survey undertaken to date in the UK. But the OPAL approach of using untrained volunteers and largely anonymous data submission exacerbates quality control concerns. A number of approaches were used in order to address data quality issues including: sensitivity analysis to determine differences due to operator, sampling effort and duration; direct comparisons of identification between participants and experienced scientists; the use of a self-assessment identification quiz; the use of multiple participant surveys to assess data variability at single sites over short periods of time; comparison of survey techniques with other measurement variables and with other metrics generally considered more accurate. These quality control approaches were then used to screen the OPAL Water Survey data to generate a more robust dataset. RESULTS: The OPAL Water Survey results provide a regional and national assessment of water quality as well as a first national picture of water clarity (as suspended solids concentrations). Less than 10 % of lakes and ponds surveyed were 'poor' quality while 26.8 % were in the highest water quality band. CONCLUSIONS: It is likely that there will always be a question mark over untrained volunteer generated data simply because quality assurance is uncertain, regardless of any post hoc data analyses. Quality control at all stages, from survey design, identification tests, data submission and interpretation can all increase confidence such that useful data can be generated by public participants.


Assuntos
Controle de Qualidade , Qualidade da Água/normas , Coleta de Dados/métodos , Monitoramento Ambiental/métodos , Reino Unido , Voluntários
4.
Sci Rep ; 13(1): 6529, 2023 Apr 21.
Artigo em Inglês | MEDLINE | ID: mdl-37085561

RESUMO

Spheroidal carbonaceous particles (SCPs) are a component of fly-ash, the particulate by-product of industrial high temperature combustion of fuel-oil and coal-series fuels. We provide the first evidence that these indelible markers of industrialisation have been deposited in Antarctic ice, thousands of kilometres from any potential source. The earliest observed particle was deposited in an ice layer from 1936 CE. While depositional fluxes are low, chemical analysis of individual SCPs indicates a coal combustion origin.

5.
Leukemia ; 20(4): 572-82, 2006 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-16482213

RESUMO

The fusion tyrosine kinases (FTKs) are generated by chromosomal translocations creating bipartite proteins in which the kinase is hyperactivated by an adjoining oligomerization domain. Autophosphorylation of the FTK generates a 'signalosome', an ensemble of signalling proteins that transduce signals to downstream pathways. At the earliest stages of oncogenesis, FTKs can mimic mitogenic cytokine signalling pathways involving the GAB-2 adaptor protein and signal transducers and activators of transcription (STAT) factors, generating replicative stress and thereby promoting a mutator phenotype. In parallel, FTKs couple to survival pathways that upregulate prosurvival proteins such as Bcl-xL, so preventing DNA-damage-induced apoptosis. Following transformation, FTKs induce resistance to genotoxic attack by upregulating DNA repair mechanisms such as STAT5-dependent RAD51 transcription. The phenomenon of 'oncogene addiction' reflects the continued requirement of an active FTK 'signalosome' to mediate survival and mitogenic signals involving the PI 3-kinase and mitogen-activated protein stress-activated protein kinase pathways, and the nuclear factor-kappa B, activator protein 1 and STAT transcription factors. The available data so far suggest that FTKs, with some possible exceptions, induce and maintain the transformed state using similar panoplies of signals, a finding with important therapeutic implications. The FTK signalling field has matured to an exciting phase in which rapid advances are facilitating rational drug design.


Assuntos
Transformação Celular Neoplásica , Células-Tronco Hematopoéticas/metabolismo , Proteínas de Fusão Oncogênica/metabolismo , Proteínas Tirosina Quinases/metabolismo , Transdução de Sinais , Animais , Variação Genética , Humanos , Proteínas de Fusão Oncogênica/genética , Proteínas Tirosina Quinases/genética
6.
Poult Sci ; 96(8): 2889-2898, 2017 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-28444343

RESUMO

Adding lysolecithin to feed has reportedly improved the performance of broiler chickens. Lysolecithin is generated by phospholipase catalyzed hydrolysis of lecithin. The enzymatic reaction converts various phospholipids into the corresponding lysophospholipids, with lysophosphatidylcholine (LPC) one of the primary products. Here we compared supplementation with a commercial lysolecithin (Lysoforte®) with comparable levels of highly purified LPC for effects on broilers. Despite no differences in weight gain during the starter period, we discovered a significant increase in average villus length with lysolecithin and an increase in villus width with purified LPC. High-throughput gene expression microarray analyses revealed many more genes were regulated in the epithelium of the jejunum by lysolecithin compared to purified LPC. The most up-regulated genes and pathways were for collagen, extracellular matrix, and integrins. Staining sections of the jejunum with Picrosirius Red confirmed the increased deposition of collagen fibrils in the villi of broilers fed lysolecithin, but not purified LPC. Thus, lysolecithin elicits gene expression in the intestinal epithelium, leading to enhanced collagen deposition and villus length. Purified LPC alone as a supplement does not mimic these responses. Feed supplementation with lysolecithin triggers changes in the intestinal epithelium with the potential to improve overall gut health and performance.


Assuntos
Proteínas Aviárias/genética , Galinhas/fisiologia , Colágeno/genética , Jejuno/efeitos dos fármacos , Lisofosfatidilcolinas/metabolismo , Ração Animal/análise , Fenômenos Fisiológicos da Nutrição Animal/efeitos dos fármacos , Animais , Proteínas Aviárias/metabolismo , Galinhas/genética , Colágeno/metabolismo , Dieta/veterinária , Suplementos Nutricionais/análise , Mucosa Intestinal/efeitos dos fármacos , Mucosa Intestinal/fisiologia , Jejuno/fisiologia , Lisofosfatidilcolinas/administração & dosagem , Masculino
7.
Eur J Surg Oncol ; 43(8): 1393-1401, 2017 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-28596034

RESUMO

BACKGROUND: Breast implant-associated anaplastic large-cell lymphoma (BIA-ALCL) is a rare, Non-Hodgkin lymphoma arising in the capsule of breast implants. BIA-ALCL presents as a recurrent effusion and/or mass. Tumours exhibit CD30 expression and are negative for Anaplastic Lymphoma Kinase (ALK). We report the multi-disciplinary management of the UK series and how the stage of disease may be used to stratify treatment. METHODS: Between 2012 and 2016, 23 cases of BIA-ALCL were diagnosed in 15 regional centres throughout the UK. Data on breast implant surgeries, clinical features, treatment and follow-up were available for 18 patients. RESULTS: The mean lead-time from initial implant insertion to diagnosis was 10 years (range: 3-16). All cases were observed in patients with textured breast implants or expanders. Fifteen patients with breast implants presented with stage I disease (capsule confined), and were treated with implant removal and capsulectomy. One patient received adjuvant chest-wall radiotherapy. Three patients presented with extra-capsular masses (stage IIA). In addition to explantation, capsulectomy and excision of the mass, all patients received neo-/adjuvant chemotherapy with CHOP as first line. One patient progressed on CHOP but achieved pathological complete response (pCR) with Brentuximab Vedotin. After a mean follow-up of 23 months (range: 1-56) all patients reported here remain disease-free. DISCUSSION: BIA-ALCL is a rare neoplasm with a good prognosis. Our data support the recommendation that stage I disease be managed with surgery alone. Adjuvant chemotherapy may be required for more invasive disease and our experience has shown the efficacy of Brentuximab as a second line treatment.


Assuntos
Implantes de Mama/efeitos adversos , Neoplasias da Mama/etiologia , Neoplasias da Mama/terapia , Consentimento Livre e Esclarecido , Linfoma Anaplásico de Células Grandes/etiologia , Linfoma Anaplásico de Células Grandes/terapia , Adulto , Idoso , Neoplasias da Mama/epidemiologia , Neoplasias da Mama/patologia , Terapia Combinada , Remoção de Dispositivo , Feminino , Humanos , Linfoma Anaplásico de Células Grandes/epidemiologia , Linfoma Anaplásico de Células Grandes/patologia , Pessoa de Meia-Idade , Estadiamento de Neoplasias , Resultado do Tratamento , Reino Unido/epidemiologia
8.
Leukemia ; 19(7): 1128-34, 2005 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-15902287

RESUMO

The nucleophosmin-anaplastic lymphoma kinase (NPM-ALK) is generated as a t(2;5) chromosomal breakpoint product, typically in CD30(+) anaplastic large cell lymphomas. Activation of the NPM-ALK tyrosine kinase by NPM dimerisation causes autophosphorylation at multiple tyrosine residues and the consequent recruitment of a 'signalosome' that couples the fusion protein to pathways regulating mitogenesis and apoptosis. This review focuses on recent advances in our understanding of the transforming signals induced by this fusion protein in mouse models.


Assuntos
Linfoma/imunologia , Proteínas de Fusão Oncogênica/imunologia , Proteínas Tirosina Quinases/imunologia , Animais , Modelos Animais de Doenças , Humanos , Linfoma/genética , Camundongos , Camundongos Transgênicos , Proteínas de Fusão Oncogênica/genética , Fosforilação , Proteínas Tirosina Quinases/genética , Transdução de Sinais/genética , Transdução de Sinais/imunologia
9.
Leukemia ; 14(10): 1796-802, 2000 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-11021755

RESUMO

We have used the bone marrow micronucleus assay (BMMN) as a measure of clastogenicity, in response to etoposide exposure in murine bone marrow. Oral delivery of etoposide resulted in a reduced number of micronucleated polychromatic erythrocytes (MPE) relative to the same dose delivered intraperitoneally (P < 0.001). Daily fractionation of the oral schedule of etoposide led to a more than six-fold increase in cumulative MPE frequency over that observed with the same total, unfractionated dose, with the potency of the response increasing with serial exposure (r = 0.79). Retrovirally-mediated expression of MDR1 in murine bone marrow resulted in partial protection against the clastogenic activity of etoposide relative to mock transduced control mice. The model system developed has indicated a variety of factors able to influence the genotoxicity of etoposide. It should now be possible to further exploit this model in order to define other factors governing haemopoietic sensitivity to etoposide.


Assuntos
Membro 1 da Subfamília B de Cassetes de Ligação de ATP/genética , Antineoplásicos Fitogênicos/farmacologia , Medula Óssea/efeitos dos fármacos , Etoposídeo/farmacologia , Transferência Genética Horizontal , Animais , Antineoplásicos Fitogênicos/administração & dosagem , Vias de Administração de Medicamentos , Esquema de Medicação , Etoposídeo/administração & dosagem , Feminino , Masculino , Camundongos , Testes para Micronúcleos
10.
Mech Dev ; 136: 99-110, 2015 May.
Artigo em Inglês | MEDLINE | ID: mdl-25617760

RESUMO

We present a complete staging table of normal development for the lungless salamander, Hemidactylium scutatum (Caudata: Plethodontidae). Terrestrial egg clutches from naturally ovipositing females were collected and maintained at 15 °C in the laboratory. Observations, photographs, and time-lapse movies of embryos were taken throughout the 45-day embryonic period. The complete normal table of development for H. scutatum is divided into 28 stages and extends previous analyses of H. scutatum embryonic development (Bishop, 1920; Humphrey, 1928). Early embryonic stage classifications through neurulation reflect criteria described for Xenopus laevis, Ambystoma maculatum and other salamanders. Later embryonic stage assignments are based on unique features of H. scutatum embryos. Additionally, we provide morphological analysis of gastrulation and neurulation, as well as details on external aspects of eye, gill, limb, pigmentation, and tail development to support future research related to phylogeny, comparative embryology, and molecular mechanisms of development.


Assuntos
Desenvolvimento Embrionário/fisiologia , Organogênese/fisiologia , Urodelos/embriologia , Animais , Feminino , Gastrulação/fisiologia , Neurulação/fisiologia
11.
Oncogene ; 34(14): 1843-52, 2015 Apr 02.
Artigo em Inglês | MEDLINE | ID: mdl-24814516

RESUMO

Cancer stem cells or tumour-propagating cells (TPCs) have been identified for a number of cancers, but data pertaining to their existence in lymphoma so far remain elusive. We show for the first time that a small subset of cells purified from human anaplastic lymphoma kinase (ALK)-positive and -negative, anaplastic large cell lymphoma cell lines and primary patient tumours using the side population (SP) technique have serial tumour-propagating capacity both in vitro and in vivo; they give rise to both themselves and the bulk tumour population as well as supporting growth of the latter through the production of soluble factors. In vivo serial dilution assays utilising a variety of model systems inclusive of human cell lines, primary human tumours and nucleophosmin (NPM)-ALK-induced murine tumours demonstrate the TPC frequency to vary from as many as 1/54 to 1/1336 tumour cells. In addition, the SP cells express higher levels of pluripotency-associated transcription factors and are enriched for a gene expression profile consistent with early thymic progenitors. Finally, our data show that the SP cells express higher levels of the NPM-ALK oncogene and are sensitive to an ALK inhibitor.


Assuntos
Linfoma Anaplásico de Células Grandes/patologia , Proteínas Nucleares/metabolismo , Receptores Proteína Tirosina Quinases/metabolismo , Células da Side Population/citologia , Células da Side Population/metabolismo , Adulto , Idoso de 80 Anos ou mais , Quinase do Linfoma Anaplásico , Animais , Antineoplásicos Fitogênicos/farmacologia , Apoptose , Linhagem Celular Tumoral , Proliferação de Células , Sobrevivência Celular , Criança , Pré-Escolar , Crizotinibe , Etoposídeo/farmacologia , Feminino , Perfilação da Expressão Gênica , Humanos , Linfoma Anaplásico de Células Grandes/genética , Camundongos , Camundongos Endogâmicos C57BL , Pessoa de Meia-Idade , Células-Tronco Neoplásicas/citologia , Nucleofosmina , Células-Tronco Pluripotentes/citologia , Inibidores de Proteínas Quinases/farmacologia , Proteínas Proto-Oncogênicas c-kit/biossíntese , Pirazóis/farmacologia , Piridinas/farmacologia , Receptores Proteína Tirosina Quinases/antagonistas & inibidores , Transdução de Sinais
12.
Mutat Res ; 493(1-2): 139-47, 2001 Jun 27.
Artigo em Inglês | MEDLINE | ID: mdl-11516723

RESUMO

The topoisomerase II inhibitor etoposide is used routinely to treat a variety of cancers in patients of all ages. As a result of its extensive use in the clinic and its association with secondary malignancies it has become a compound of great interest with regard to its genotoxic activity in vivo. This paper describes a series of assays that were employed to determine the in vivo genotoxicity of etoposide in a murine model system. The alkaline comet assay detected DNA damage in the bone marrow mononuclear compartment over the dose range of 10--100mg/kg and was associated with a large and dose dependent rise in the proportion of cells with severely damaged DNA. In contrast, the bone marrow micronucleus assay was found to be sensitive to genotoxic damage between the doses of 0.1--1mg/kg without any corresponding increases in cytotoxicity. An increase in the mutant frequency was undetectable at the Hprt locus at administered doses of 1 and 10mg/kg of etoposide, however, an increase in the mutant frequency was seen at the Aprt locus at these doses. We conclude that the BMMN assay is a good short-term predictor of the clastogenicity of etoposide at doses that do not result in cytotoxic activity, giving an indication of potential mutagenic effects. Moreover, the detection of mutants at the Aprt locus gives an indication of the potential of etoposide to cause chromosomal mutations that may lead to secondary malignancy.


Assuntos
Etoposídeo/toxicidade , Testes de Mutagenicidade/métodos , Mutagênicos/toxicidade , Adenina Fosforribosiltransferase/genética , Animais , Antineoplásicos Fitogênicos/toxicidade , Ensaio Cometa , Humanos , Hipoxantina Fosforribosiltransferase/genética , Hibridização in Situ Fluorescente , Masculino , Camundongos , Testes para Micronúcleos , Baço/efeitos dos fármacos , Baço/enzimologia , Inibidores da Topoisomerase II
13.
Ann Dyslexia ; 39(1): 247-67, 1989 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-24233483

RESUMO

A longitudinal study followed the progress of a group of elementary SLD students as they were instructed using the Alphabetic Phonics (AP) curriculum. After a three year period, the AP curriculum produced positive results in reading comprehension for most SLD students, particularly those who began the program in first and second grade. Students in resource and self-contained settings made significant gains in reading comprehension, although the two types of students exhibited different patterns of progress. Students of different ability levels responded differently to the AP curriculum. Average and above average students made significant progress in reading comprehension, but below average students did not advance substantially in relation to their ability level. At the end of three years, classroom teachers had a significantly more positive view of students' word attack, oral reading, and silent reading comprehension skills.

14.
Gen Dent ; 46(2): 190-3, 1998.
Artigo em Inglês | MEDLINE | ID: mdl-9663076

RESUMO

In order to compare the effect of beverages "imported" from nearby communities on the fluoride intake of a fluoridated community with that of a nonfluoridated community, 45 different carbonated and juice drinks were sampled from Houston (fluoridated) and San Antonio (nonfluoridated) and examined for their fluoride concentrations. In spite of the fact that an individual lives in a low fluoride community, the risk of fluorosis exists through fluoride consumption in beverages as well as from the water supply and fluoride therapy. It is therefore important for dental practitioners to carefully evaluate their patients' entire fluoride exposure before prescribing fluoride supplements.


Assuntos
Bebidas Gaseificadas/efeitos adversos , Fluoretação , Fluorose Dentária/etiologia , Adolescente , Criança , Suplementos Nutricionais/efeitos adversos , Fluoretos/administração & dosagem , Fluoretos/efeitos adversos , Fluoretos/análise , Fluorose Dentária/prevenção & controle , Humanos , Texas , Água/química
15.
J Dent Hyg ; 75(1): 21-4, 2001.
Artigo em Inglês | MEDLINE | ID: mdl-11314222

RESUMO

PURPOSE: The purpose of this study was to evaluate the clinical effect of topical fluoride on retention of light-cured (CLC) and self-cured (CSC) pit and fissure sealants. METHODS: CLC and CSC sealants were placed in vivo on opposite sides of the arch before and after fluoride treatment. A total of 122 sealants were placed on virgin permanent molars and premolars of 16 dental hygiene students enrolled in a two-year program. Sealant retention in both fluoridated and non-fluoridated teeth was evaluated at 6, 12, and 18 month intervals. RESULTS: Overall sealant retention for both fluoridated and non-fluoridated teeth at 6, 12 and 18 months was 68%, 48%, and 49%, respectively. There was a significant difference (p < 0.001) when fluoridated vs. non-fluoridated teeth were compared. Retention was greater on the fluoridated teeth, with respect to the sealant material (CLC-fluoride). Significant differences (p < 0.001) were found when CLC-fluoride and CLC-no fluoride treatment groups were compared. However, no significant differences were found in retention when CSC-fluoride and CSC-no fluoride groups were compared, or when CLC was compared to CSC irrespective of fluoridation. Significant differences (p < 0.0001) were found when sealant retention on molars was compared to premolars--retention of sealants was greater on premolars. CONCLUSION: This study suggests that sealant retention may not be adversely affected by a topical fluoride treatment applied immediately prior to placement.


Assuntos
Cariostáticos/química , Colagem Dentária , Fluoretos Tópicos/química , Selantes de Fossas e Fissuras/química , Fluoreto de Fosfato Acidulado/química , Fluoreto de Fosfato Acidulado/uso terapêutico , Dente Pré-Molar , Bis-Fenol A-Glicidil Metacrilato/química , Bis-Fenol A-Glicidil Metacrilato/uso terapêutico , Cariostáticos/uso terapêutico , Distribuição de Qui-Quadrado , Cárie Dentária/classificação , Profilaxia Dentária , Fluoretos Tópicos/uso terapêutico , Seguimentos , Humanos , Dente Molar , Variações Dependentes do Observador , Selantes de Fossas e Fissuras/uso terapêutico , Propriedades de Superfície
18.
Leukemia ; 23(8): 1432-40, 2009 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-19295548

RESUMO

Bcr-Abl causes chronic myelogenous leukemia, a myeloproliferative disorder characterized by clonal expansion of hematopoietic progenitor cells. In this study, inducible expression of Bcr-Abl in TonB.210 cells is associated with increased production of intracellular reactive oxygen species (ROS), which is thought to play a role in survival signaling when generated at specific levels. Elevated ROS in Bcr-Abl-expressing cells were found to activate PI3k/Akt pathway members such as Akt and GSK3beta as well as downstream targets beta-catenin and Mcl-1. The activation of these proteins was inhibited by the flavoprotein inhibitor diphenyleneiodonium, which is commonly used to inhibit NADPH oxidase (Nox). This indicated that increased ROS might be related to increased activity of one member of the Nox family. Knock-down experiments using siRNA suggest that Nox-4 is the main source of increased ROS following Bcr-Abl expression. We showed that Bcr-Abl-induced ROS could also increase survival pathway signaling through redox inhibition of PP1alpha, a serine threonine phosphatase that negatively regulates the PI3k/Akt pathway. Overall our results demonstrate that Bcr-Abl expression increases Nox-4-generated ROS, which in turn increases survival signaling through PI3k/Akt pathway by inhibition of PP1alpha, thus contributing to the high level of resistance to apoptosis seen in these Bcr-Abl-expressing cells.


Assuntos
Proteínas de Fusão bcr-abl/fisiologia , Leucemia Mielogênica Crônica BCR-ABL Positiva/fisiopatologia , Proteínas de Neoplasias/fisiologia , Fosfatidilinositol 3-Quinases/fisiologia , Proteínas Proto-Oncogênicas c-akt/fisiologia , Transdução de Sinais/fisiologia , Apoptose/fisiologia , Linhagem Celular Tumoral/metabolismo , Quinase 3 da Glicogênio Sintase/metabolismo , Glicogênio Sintase Quinase 3 beta , Humanos , Peróxido de Hidrogênio/metabolismo , Proteína de Sequência 1 de Leucemia de Células Mieloides , NADPH Oxidase 4 , NADPH Oxidases/antagonistas & inibidores , NADPH Oxidases/genética , NADPH Oxidases/fisiologia , Oniocompostos/farmacologia , Oxirredução , Proteína Fosfatase 1/antagonistas & inibidores , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , RNA Interferente Pequeno/farmacologia , Espécies Reativas de Oxigênio/metabolismo , beta Catenina/metabolismo
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