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1.
BMC Cancer ; 18(1): 1238, 2018 Dec 10.
Artigo em Inglês | MEDLINE | ID: mdl-30526542

RESUMO

BACKGROUND: COPD patients are at increased risk of developing non-small cell lung carcinoma that has a worse prognosis. Oxidative stress contributes to carcinogenesis and is increased in COPD patients due to mitochondrial dysfunction. We determined whether mitochondrial dysfunction is a contributing factor to the reduced survival of COPD patients with non-small cell lung carcinoma (NSCLC). METHODS: Using a transcriptomic database and outcome data of 3553 NSCLC samples, we selected mitochondrial-related genes whose levels in the tumour correlated with patient mortality. We further selected those genes showing a ≥ 2 fold expression in cancer compared to normal tissue. Cell-type specific expression of these proteins in lung tissue from NSCLC patients who were non-smokers or smokers with or without COPD (healthy smokers) was determined by immunohistochemistry. Gene set variation analysis was used in additional NSCLC datasets to determine the relative expression of specific macrophage transcriptomic signatures within lung cancer tissue. RESULTS: The expression of 14 mitochondrial-related genes was correlated with patient mortality and these were differentially expressed between cancer and normal lung tissue. We studied further the expression of one of these genes, PGAM5 which is a regulator of mitochondrial degradation by mitophagy. In background lung tissue, PGAM5 was only expressed in alveolar macrophages, with the highest expression in smokers with COPD compared to healthy smokers and non-smokers. In cancerous tissue, only the malignant epithelial cells and associated macrophages at the periphery of the cancer expressed PGAM5. Pre-neoplastic epithelium also showed the expression of PGAM5. There was no difference in expression in cancer tissue between COPD, healthy smoker and non-smoker groups. Macrophages at the edge of the cancer from COPD patients showed a trend towards higher expression of PGAM5 compared to those from the other groups. There was a significant correlation between PGAM5 expression in cancer tissue and the level of expression of 9 out of 49 previously-defined macrophage transcriptomic signatures with a particular one associated with patient mortality (p < 0.05). CONCLUSION: PGAM5 is expressed in pre-neoplastic tissue and NSCLC, but not in normal epithelium. The association between PGAM5 expression and patient mortality may be mediated through the induction of specific macrophage phenotypes.


Assuntos
Carcinoma Pulmonar de Células não Pequenas/etiologia , Neoplasias Pulmonares/etiologia , Macrófagos Alveolares/metabolismo , Proteínas Mitocondriais/metabolismo , Fosfoproteínas Fosfatases/metabolismo , Doença Pulmonar Obstrutiva Crônica/complicações , Idoso , Carcinoma Pulmonar de Células não Pequenas/metabolismo , Feminino , Humanos , Neoplasias Pulmonares/metabolismo , Neoplasias Pulmonares/mortalidade , Masculino , Pessoa de Meia-Idade , Estresse Oxidativo/fisiologia , Doença Pulmonar Obstrutiva Crônica/metabolismo , Doença Pulmonar Obstrutiva Crônica/mortalidade , Transcriptoma
2.
B-ENT ; Suppl 24: 7-13, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26891526

RESUMO

Head and Neck cancer can be treated by non-surgical or surgical modalities. Current surgical techniques include open surgery and transoral resections. The latter have the distinct advantage of quicker recovery and reduced hospital stay. The further down the aerodigestive tract tumours are sited, the more difficult is the transoral access, requiring techniques that combine magnification and finer instrumentation. Thus, while oral cavity tumours can be removed transorally without special equipment, the need to address oropharyngeal and laryngeal cancers led to the evolution of transoral laser microsurgery. Transoral robotic surgery (TORS) improves the visualisation, the instrumentation and the ergonomics in transoral resections and is also used primarily in the treatment of oropharyngeal and laryngeal cancer. Current evidence suggests that the oncologic and functional outcome of TORS surgery is good as speech and swallowing mechanisms are better preserved. This review will provide the reader an insight into the role of TORS in head and neck practice.


Assuntos
Neoplasias de Cabeça e Pescoço/cirurgia , Cirurgia Endoscópica por Orifício Natural/métodos , Procedimentos Cirúrgicos Otorrinolaringológicos/métodos , Robótica/métodos , Humanos , Boca
3.
Ann R Coll Surg Engl ; 96(2): e5-6, 2014 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-24780654

RESUMO

It is well established that angiosarcoma can develop following radiotherapy. We present an unusual case of angiosarcoma of the pharynx that developed three years after treatment with surgery and adjuvant chemoradiotherapy for a T2N2bM0 squamous cell carcinoma of the oropharynx. The patient was tumour free until developing dysphagia, which was found to be caused by an angiosarcoma. The patient underwent surgery of the pharyngeal angiosarcoma by laryngopharyngectomy, tongue base resection, selective neck dissection and radial forearm microvascular free flap reconstruction. Angiosarcoma following head and neck malignancy is rare but must be considered as part of the differential diagnosis in patients with new symptoms after radiotherapy.


Assuntos
Carcinoma de Células Escamosas/terapia , Hemangiossarcoma/etiologia , Neoplasias Induzidas por Radiação/etiologia , Neoplasias Orofaríngeas/terapia , Neoplasias Faríngeas/etiologia , Quimiorradioterapia Adjuvante/efeitos adversos , Transtornos de Deglutição/etiologia , Antebraço , Hemangiossarcoma/cirurgia , Humanos , Laringectomia/métodos , Masculino , Pessoa de Meia-Idade , Esvaziamento Cervical/métodos , Neoplasias Induzidas por Radiação/cirurgia , Neoplasias Faríngeas/cirurgia , Faringectomia/métodos , Retalhos Cirúrgicos , Língua/cirurgia
4.
PLoS One ; 9(1): e84640, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24416257

RESUMO

OBJECTIVES: Smoking during pregnancy may cause many health problems for pregnant women and their newborns. However, there is a paucity of research that has examined the predictors of smoking during pregnancy in Canada. This study used data from the 2009-2010 Canadian Community Health Survey (CCHS) to estimate the prevalence of smoking during pregnancy and examine the demographic, socioeconomic, health-related and behavioral determinants of this behavior. METHODS AND FINDINGS: The data were obtained from the 2009-2010 CCHS master data file. Weighted estimates of the prevalence were calculated. Multivariable logistic regression was used to determine demographic, socioeconomic, health related and behavioral characteristics associated with smoking behavior during pregnancy. Women living in the Northern Territories had a high rate of smoking during pregnancy (59.3%). The prevalence of smoking during pregnancy was also high among women under 25 years old, of low socioeconomic status, who reported not having a regular medical doctor, being fair to poor in self-perceived health, having at least one chronic disease, having at least one mental illness, being heavy smokers, and being regular alcohol drinkers. Results from multivariable logistic regression revealed that the odds of smoking during pregnancy were decreased with increasing age (odds ratio [OR], 0.95; 95% confidence interval [CI], 0.91-0.99), having a regular family doctor [OR, 0.24; 95% CI, 0.11-0.52], having highest level of family income [OR, 0.09; 95% CI, 0.03-0.29]. Mothers who reported poor or fair self-perceived health [OR, 2.13; 95% CI, 0.96-4.71] and those who had at least one mental illness [OR, 1.81; 95% CI, 1.00-3.28] had greater odds of smoking during pregnancy. CONCLUSIONS: There are a number of demographic, socio-economic, health-related and behavioral characteristics that should be considered in developing and implementing effective population health promotional strategies to prevent smoking during pregnancy, promoting health and well-being of pregnant women and their newborns.


Assuntos
Inquéritos Epidemiológicos , Gestantes , Características de Residência/estatística & dados numéricos , Fumar/epidemiologia , Adolescente , Adulto , Canadá/epidemiologia , Demografia , Feminino , Humanos , Modelos Logísticos , Pessoa de Meia-Idade , Análise Multivariada , Gravidez , Fatores Socioeconômicos , Adulto Jovem
5.
PLoS One ; 8(9): e72386, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-24039755

RESUMO

Cadherin-17 (CDH17) is an oncofetal molecule associated with poor prognostic outcomes of hepatocellular carcinoma (HCC), for which the treatment options are very limited. The present study investigates the therapeutic potential of a monoclonal antibody (Lic5) that targets the CDH17 antigen in HCC. In vitro experiments showed Lic5 could markedly reduce CDH17 expression in a dose-dependent manner, suppress ß-catenin signaling, and induce cleavages of apoptotic enzymes caspase-8 and -9 in HCC cells. Treatment of animals in subcutaneous HCC xenograft model similarly demonstrated significant tumor growth inhibition (TGI) using Lic5 antibody alone (5 mg/kg, i.p., t.i.w.; ca.60-65% TGI vs. vehicle at day 28), or in combination with conventional chemotherapy regimen (cisplatin 1 mg/kg; ca. 85-90% TGI). Strikingly, lung metastasis was markedly suppressed by Lic5 treatments. Immunohistochemical and western blot analyses of xenograft explants revealed inactivation of the Wnt pathway and suppression of Wnt signaling components in HCC tissues. Collectively, anti-CDH17 antibody promises as an effective biologic agent for treating malignant HCC.


Assuntos
Anticorpos Monoclonais/farmacologia , Antineoplásicos/farmacologia , Carcinoma Hepatocelular/tratamento farmacológico , Neoplasias Hepáticas/tratamento farmacológico , Via de Sinalização Wnt/efeitos dos fármacos , Animais , Anticorpos Monoclonais/uso terapêutico , Antineoplásicos/uso terapêutico , Caderinas/imunologia , Caderinas/metabolismo , Carcinogênese/efeitos dos fármacos , Carcinoma Hepatocelular/metabolismo , Caspase 8/metabolismo , Caspase 9/metabolismo , Linhagem Celular Tumoral , Humanos , Neoplasias Hepáticas/metabolismo , Camundongos , Camundongos Endogâmicos BALB C , Carga Tumoral/efeitos dos fármacos , Ensaios Antitumorais Modelo de Xenoenxerto , beta Catenina/metabolismo
6.
Nat Genet ; 44(7): 765-9, 2012 May 27.
Artigo em Inglês | MEDLINE | ID: mdl-22634754

RESUMO

To survey hepatitis B virus (HBV) integration in liver cancer genomes, we conducted massively parallel sequencing of 81 HBV-positive and 7 HBV-negative hepatocellular carcinomas (HCCs) and adjacent normal tissues. We found that HBV integration is observed more frequently in the tumors (86.4%) than in adjacent liver tissues (30.7%). Copy-number variations (CNVs) were significantly increased at HBV breakpoint locations where chromosomal instability was likely induced. Approximately 40% of HBV breakpoints within the HBV genome were located within a 1,800-bp region where the viral enhancer, X gene and core gene are located. We also identified recurrent HBV integration events (in ≥ 4 HCCs) that were validated by RNA sequencing (RNA-seq) and Sanger sequencing at the known and putative cancer-related TERT, MLL4 and CCNE1 genes, which showed upregulated gene expression in tumor versus normal tissue. We also report evidence that suggests that the number of HBV integrations is associated with patient survival.


Assuntos
Carcinoma Hepatocelular/genética , Carcinoma Hepatocelular/virologia , Vírus da Hepatite B/genética , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/virologia , Integração Viral/genética , Sequência de Bases , Instabilidade Cromossômica/genética , Ciclina E/genética , Variações do Número de Cópias de DNA/genética , DNA Viral/genética , Proteínas de Ligação a DNA/genética , Feminino , Histona-Lisina N-Metiltransferase , Humanos , Masculino , Pessoa de Meia-Idade , Dados de Sequência Molecular , Proteínas Oncogênicas/genética , RNA Viral/genética , Taxa de Sobrevida , Telomerase/genética
7.
PLoS One ; 6(9): e24582, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-21949730

RESUMO

Biomarkers derived from gene expression profiling data may have a high false-positive rate and must be rigorously validated using independent clinical data sets, which are not always available. Although animal model systems could provide alternative data sets to formulate hypotheses and limit the number of signatures to be tested in clinical samples, the predictive power of such an approach is not yet proven. The present study aims to analyze the molecular signatures of liver cancer in a c-MET-transgenic mouse model and investigate its prognostic relevance to human hepatocellular carcinoma (HCC). Tissue samples were obtained from tumor (TU), adjacent non-tumor (AN) and distant normal (DN) liver in Tet-operator regulated (TRE) human c-MET transgenic mice (n = 21) as well as from a Chinese cohort of 272 HBV- and 9 HCV-associated HCC patients. Whole genome microarray expression profiling was conducted in Affymetrix gene expression chips, and prognostic significances of gene expression signatures were evaluated across the two species. Our data revealed parallels between mouse and human liver tumors, including down-regulation of metabolic pathways and up-regulation of cell cycle processes. The mouse tumors were most similar to a subset of patient samples characterized by activation of the Wnt pathway, but distinctive in the p53 pathway signals. Of potential clinical utility, we identified a set of genes that were down regulated in both mouse tumors and human HCC having significant predictive power on overall and disease-free survival, which were highly enriched for metabolic functions. In conclusions, this study provides evidence that a disease model can serve as a possible platform for generating hypotheses to be tested in human tissues and highlights an efficient method for generating biomarker signatures before extensive clinical trials have been initiated.


Assuntos
Carcinoma Hepatocelular/diagnóstico , Carcinoma Hepatocelular/genética , Neoplasias Hepáticas/diagnóstico , Neoplasias Hepáticas/genética , Proteínas Proto-Oncogênicas c-met/genética , Transcriptoma , Animais , Carcinoma Hepatocelular/metabolismo , Carcinoma Hepatocelular/patologia , Modelos Animais de Doenças , Feminino , Humanos , Fígado/citologia , Fígado/metabolismo , Fígado/patologia , Neoplasias Hepáticas/metabolismo , Neoplasias Hepáticas/patologia , Masculino , Camundongos , Camundongos Transgênicos , Prognóstico , Análise de Sobrevida
8.
J Biol Chem ; 286(35): 30706-30713, 2011 Sep 02.
Artigo em Inglês | MEDLINE | ID: mdl-21737452

RESUMO

Hepatocellular carcinoma (HCC) is a heterogeneous and highly aggressive malignancy, for which there are no effective cures. Identification of a malignant stemlike subtype of HCC may offer patients with a dismal prognosis a potential targeted therapy using c-MET and Wnt pathway inhibitors. MicroRNAs (miRNAs) show promise as diagnostic and prognostic tools for cancer detection and stratification. Using a TRE-c-Met-driven transgenic HCC mouse model, we identified a cluster of 23 miRNAs that is encoded within the Dlk1-Gtl2 imprinted region on chromosome 12qF1 overexpressed in all of the isolated liver tumors. Interestingly, this region is conserved among mammalian species and maps to the human DLK1-DIO3 region on chromosome 14q32.2. We thus examined the expression of the DLK1-DIO3 miRNA cluster in a cohort of 97 hepatitis B virus-associated HCC patients and identified a subgroup (n = 18) of patients showing strong coordinate overexpression of miRNAs in this cluster but not in other cancer types (breast, lung, kidney, stomach, and colon) that were tested. Expression levels of imprinted gene transcripts from neighboring loci in this 14q32.2 region and from a subset of other imprinted sites were concomitantly elevated in human HCC. Interestingly, overexpression of the DLK1-DIO3 miRNA cluster was positively correlated with HCC stem cell markers (CD133, CD90, EpCAM, Nestin) and associated with a high level of serum α-fetoprotein, a conventional biomarker for liver cancer, and poor survival rate in HCC patients. In conclusion, our findings suggest that coordinate up-regulation of the DLK1-DIO3 miRNA cluster at 14q32.2 may define a novel molecular (stem cell-like) subtype of HCC associated with poor prognosis.


Assuntos
Carcinoma Hepatocelular/genética , Carcinoma Hepatocelular/mortalidade , Cromossomos Humanos Par 14/genética , Peptídeos e Proteínas de Sinalização Intercelular/genética , Iodeto Peroxidase/genética , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/mortalidade , Proteínas de Membrana/genética , MicroRNAs/genética , Biomarcadores Tumorais/metabolismo , Proteínas de Ligação ao Cálcio , Estudos de Coortes , Humanos , Fígado/metabolismo , MicroRNAs/metabolismo , Família Multigênica , Prognóstico , Distribuição Tecidual , Resultado do Tratamento , Regulação para Cima
9.
J Nanosci Nanotechnol ; 10(8): 5427-30, 2010 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-21125912

RESUMO

Tetrapod-like Cu-ZnO nanowhiskers were synthesized by a photo-reduction technique in an aqueous solution containing Cu2+ ions. The XRD and TEM analyses revealed that the as-prepared ZnO nanowhiskers were covered by Cu coating or surrounded by Cu nanoparticles. Pure Cu nanoparticles were also produced in the solution by increasing the duration of xenon irradiation. These nanoparticles were amorphous and could be converted to crystalline structure by further electron beam irradiation. The photoluminescence measurement showed that the visible emission from the Cu-coated ZnO nanowhiskers had a blue shift when compared with that of the pure ZnO.

10.
World J Gastroenterol ; 15(38): 4745-52, 2009 Oct 14.
Artigo em Inglês | MEDLINE | ID: mdl-19824106

RESUMO

AIM: To establish the roles of lipopolysaccharide (LPS)/CD14/toll-like receptor 4 (TLR4)-mediated inflammation in a rat model of human necrotizing enterocolitis (NEC). METHODS: Six pairs of intestinal samples from human NEC were collected before and after recovery for histological and molecular analysis of inflammatory cytokines and signaling components. In the rat NEC model, we isolated 10-cm jejunum segments and divided them into six groups (n = 6) for sham operation, treatment with LPS, bowel distension, combined bowel distension and LPS stimulation, and two therapeutic groups. The potential efficacy of a recombinant CD18 peptide and a monoclonal CD14 antibody was evaluated in the latter two groups. The serum and tissue levels of several inflammatory mediators were quantified by real-time polymerase chain reaction, ELISA and immunoblotting. RESULTS: Human acute phase NEC tissues displayed significant increases (P < 0.05) in levels of TLR4, CD14, myeloid differentiation protein (MD)-2, tumor necrosis factor (TNF)-alpha and nuclear factor-kappaB when compared to those after recovery. The histological and inflammatory picture of human NEC was reproduced in rats that were treated with combined bowel distension and LPS, but not in the sham-operated and other control rats. Serum levels of interleukin-6 and TNF-alpha were also elevated. The NEC pathology was attenuated by treating the NEC rats with a monoclonal CD14 antibody or an LPS-neutralizing peptide. CONCLUSION: LPS and distension are required to produce the histological and inflammatory features of NEC. A potential treatment option is blocking LPS activation and leukocyte infiltration.


Assuntos
Enterocolite Necrosante/imunologia , Enterocolite Necrosante/metabolismo , Receptores de Lipopolissacarídeos/metabolismo , Lipopolissacarídeos/metabolismo , Receptor 4 Toll-Like/metabolismo , Animais , Modelos Animais de Doenças , Enterocolite Necrosante/fisiopatologia , Regulação da Expressão Gênica , Humanos , Inflamação , Interleucina-6/sangue , Jejuno/patologia , Ratos , Ratos Sprague-Dawley , Fator de Necrose Tumoral alfa/sangue
11.
J Bone Joint Surg Br ; 88(1): 120-2, 2006 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-16365134

RESUMO

The outcome of a cemented hip arthroplasty is partly dependent on the type of cement which is used. The production of an interface gap between the stem and the cement mantle as a result of shrinkage of the cement, may be a factor involved. Palacos R, Palacos LV (both with gentamicin), CMW 1, CMW 2, CMW Endurance (CMWE) and Simplex were prepared under vacuum and allowed to cure overnight in similar cylinders. The next day this volume was determined by the displacement of water. Shrinkage varied between 3.82% and 7.08% with CMWE having the lowest and Palacos LV the highest. This could be a factor to consider when choosing a cement for a shape-closed stem.


Assuntos
Artroplastia de Quadril/métodos , Cimentos Ósseos/química , Fenômenos Químicos , Físico-Química , Humanos , Teste de Materiais/métodos , Metilmetacrilatos/química , Polimetil Metacrilato/química , Poliestirenos/química , Vácuo
12.
Hip Int ; 16(4): 268-72, 2006.
Artigo em Inglês | MEDLINE | ID: mdl-19219804

RESUMO

The Internet has become an important source of information for patients. Websites offering medical information are not subject to peer-review. The aim of this study was to evaluate the quality of information available on the web regarding hip resurfacing arthroplasty. The search term hip resurfacing was entered into five commonly used general search engines. The 20 highest-ranked websites from each engine were reviewed, after eliminating duplicate and non-relevant sites. Each site was then given a quality score (maximum of 20) according to predefined general and specific criteria. Our search identified 40 unique websites. Commercial websites were the most common (n=17). Quality scores ranged from 8 to 18, indicating that the quality of information on the web varied widely. The mean score for all sites was 11.7, SD 2.6, and only four websites scored >15. Fifteen sites did not mention the disadvantages or complications specific to hip resurfacing. The quality of information on the Internet regarding hip resurfacing is variable. Only four sites out of 40 were deemed to be of high quality. Orthopaedic surgeons need to be aware of these limitations, and take the lead in educating and counselling their patients.;

13.
J Bone Joint Surg Br ; 87(11): 1524-6, 2005 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-16260672

RESUMO

Implantation of allograft bone is an integral part of revision surgery of the hip. One major concern with its use is the risk of transmission of infective agents. There are a number of methods of processing allograft bone in order to reduce this risk. One method requires washing the tissue using pulsed irrigation immediately before implantation. We report the incidence of deep bacterial infection in 138 patients (144 revision hip arthroplasties) who had undergone implantation of allograft bone. The bone used was fresh-frozen, non-irradiated and pulse-washed with normal saline before implantation. The deep infection rate at a minimum follow-up of one year was 0.7%. This method of processing appears to be associated with a very low risk of allograft-related bacterial infection.


Assuntos
Artroplastia de Quadril/métodos , Transplante Ósseo/métodos , Infecções Relacionadas à Prótese/etiologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Infecções Bacterianas/prevenção & controle , Infecções Bacterianas/transmissão , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Falha de Prótese , Infecções Relacionadas à Prótese/prevenção & controle , Reoperação/métodos , Estudos Retrospectivos , Cloreto de Sódio , Irrigação Terapêutica
15.
Nat Med ; 3(1): 89-93, 1997 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-8986748

RESUMO

In most mammalian cells nucleoside uptake occurs primarily via broad-specificity, es (e, equilibrative; 5, sensitive to NBMPR inhibition) transporters that are potently inhibited by nitrobenzylthioinosine (NBMPR). These transporters are essential for nucleotide synthesis by salvage pathways in hemopoietic and other cells that lack de novo pathways and are the route of cellular uptake for many cytotoxic nucleosides used in cancer and viral chemotherapy. They play an important role in adenosine-mediated regulation of many physiological processes, including neurotransmission and platelet aggregation, and are a target for coronary vasodilator drugs. We have previously reported the purification of the prototypic es transporter from human erythrocytes and have shown that this glycoprotein of apparent M, 55,000 is immunologically related to nucleoside transporters from several other species and tissues, including human placenta. Here we report the isolation of a human placental cDNA encoding a 456-residue glycoprotein with functional characteristics typical of an es-type transporter. It is predicted to possess 11 membrane-spanning regions and is homologous to several proteins of unknown function in yeast, nematodes, plants and mammals. Because of its central role in the uptake both of adenosine and of chemotherapeutic nucleosides, study of this protein should not only provide insights into the physiological roles of nucleoside transport but also open the way to improved therapies.


Assuntos
Adenosina/metabolismo , Antineoplásicos/farmacologia , Proteínas de Transporte/genética , Proteínas de Transporte/metabolismo , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Sequência de Aminoácidos , Animais , Cladribina/farmacologia , Clonagem Molecular , Citarabina/farmacologia , DNA Complementar , Bases de Dados Factuais , Transportador Equilibrativo 1 de Nucleosídeo , Humanos , Dados de Sequência Molecular , Nucleosídeos/metabolismo , Oócitos/efeitos dos fármacos , Oócitos/metabolismo , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Alinhamento de Sequência , Homologia de Sequência de Aminoácidos , Distribuição Tecidual , Uridina/metabolismo , Uridina/farmacocinética , Vidarabina/análogos & derivados , Vidarabina/farmacologia , Xenopus
17.
J Biol Chem ; 268(29): 22127-34, 1993 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-8408072

RESUMO

We have used enzymic cleavage by trypsin in conjunction with glycosidase digestion to probe the transmembrane topologies and molecular structures of mammalian equilibrative, nitrobenzylthioinosine (NBMPR)-sensitive, nucleoside transport systems. Transporters from four species (human, pig, guinea pig, and rat) and three tissues (erythrocyte, liver, and lung), which differ from each other in size and in their sensitivity to inhibition by the vasodilator dipyridamole, were investigated. Broadly equivalent sites of [3H]NBMPR photolabeling, carbohydrate attachment, and trypsin cleavage were observed for all systems. Results from these experiments demonstrate that molecular weight differences between rat transporters and those from two other species (human and guinea pig) are due largely to oligosaccharide heterogeneity and that the low dipyridamole sensitivity of rat nucleoside transporters is probably a consequence of relatively minor differences in molecular structure. In marked contrast, carbohydrate removal increases the molecular weight difference between the pig erythrocyte transporter and, for example, that in human erythrocytes. This polypeptide difference is limited largely, if not completely, to one tryptic fragment of the protein. In the case of the human erythrocyte transporter, the site of N-linked glycosylation has been located very close to one end of the protein, and the site of NBMPR photolabeling to within 16 kDa of that site. Trypsin cleavage occurs endofacially. Our results provide evidence of substantial structural conservation among mammalian NBMPR-sensitive nucleoside transporters.


Assuntos
Proteínas Sanguíneas/química , Proteínas de Transporte/química , Glicosídeo Hidrolases , Proteínas de Membrana/química , Marcadores de Afinidade , Animais , Proteínas Sanguíneas/metabolismo , Western Blotting , Proteínas de Transporte/metabolismo , Membrana Celular/química , Membrana Eritrocítica/química , Glicosilação , Cobaias , Humanos , Fígado/química , Pulmão/química , Manosil-Glicoproteína Endo-beta-N-Acetilglucosaminidase/metabolismo , Proteínas de Membrana/metabolismo , Proteínas de Transporte de Nucleosídeos , Ratos , Ratos Sprague-Dawley , Suínos , Tioinosina/análogos & derivados , Tripsina/metabolismo , beta-Galactosidase/metabolismo
20.
J Biol Chem ; 267(30): 21954-60, 1992 Oct 25.
Artigo em Inglês | MEDLINE | ID: mdl-1400505

RESUMO

Polyclonal antibodies were raised against the nitrobenzylthioinosine (NBMPR)-sensitive nucleoside transporter of human erythrocyte membranes. On Western blots of these membranes they labeled the broad "band 4.5" region (average apparent M(r) 55,000), which contains both the nucleoside and glucose transport proteins. However, they did not recognize the glucose transporter when this was prepared free of nucleoside transporter by expression from a cDNA clone. Their specificity for the nucleoside transporter was confirmed by the ability to immunoadsorb NBMPR- but not cytochalasin B-binding sites from a detergent-solubilized mixture of band 4.5 proteins. Although a large proportion of the antibodies recognized extracellular epitopes, these appeared to be located primarily on the polypeptide moiety of the glycoprotein, as demonstrated by the ability of the antibodies strongly to label the deglycosylated transporter (apparent M(r) 45,000) on Western blots. The antibodies were species-cross-reactive, recognizing nucleoside transporters from pig and rabbit erythrocytes and from rat liver. The pig protein is similar to the human transporter in its inhibitor sensitivity but is considerably larger (apparent M(r) 57,000 after deglycosylation). In contrast, the rat protein is similar in size to the human transporter (apparent M(r) 45,000 after deglycosylation) but much less sensitive to the inhibitors dilazep and dipyridamole. These findings indicate that despite their differences in size and inhibitor specificity, the NBMPR-sensitive nucleoside transporters of these mammalian species are related in amino acid sequence.


Assuntos
Proteínas Sanguíneas/metabolismo , Proteínas de Transporte/metabolismo , Proteínas de Membrana/metabolismo , Tioinosina/análogos & derivados , Marcadores de Afinidade , Animais , Anticorpos/imunologia , Proteínas Sanguíneas/genética , Proteínas Sanguíneas/imunologia , Western Blotting , Proteínas de Transporte/efeitos dos fármacos , Proteínas de Transporte/genética , Proteínas de Transporte/imunologia , Células Cultivadas , Reações Cruzadas , DNA , Ensaio de Imunoadsorção Enzimática , Membrana Eritrocítica/efeitos dos fármacos , Membrana Eritrocítica/metabolismo , Humanos , Proteínas de Membrana/efeitos dos fármacos , Proteínas de Membrana/genética , Proteínas de Membrana/imunologia , Proteínas de Transporte de Nucleosídeos , Coelhos , Homologia de Sequência do Ácido Nucleico , Especificidade por Substrato , Suínos , Tioinosina/farmacologia
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