Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 44
Filtrar
1.
Clin Oncol (R Coll Radiol) ; 32(6): 382-389, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32089356

RESUMO

AIMS: De-escalation trials are challenging and sometimes may fail due to poor recruitment. The OPTIMA Prelim randomised controlled trial (ISRCTN42400492) randomised patients with early stage breast cancer to chemotherapy versus 'test-directed' chemotherapy, with a possible outcome of no chemotherapy, which could confer less treatment relative to routine practice. Despite encountering challenges, OPTIMA Prelim reached its recruitment target ahead of schedule. This study reports the root causes of recruitment challenges and the strategies used to successfully overcome them. MATERIALS AND METHODS: A mixed-methods recruitment intervention (QuinteT Recruitment Intervention) was used to investigate the recruitment difficulties and feedback findings to inform interventions and optimise ongoing recruitment. Quantitative site-level recruitment data, audio-recorded recruitment appointments (n = 46), qualitative interviews (n = 22) with trialists/recruiting staff (oncologists/nurses) and patient-facing documentation were analysed using descriptive, thematic and conversation analyses. Findings were triangulated to inform a 'plan of action' to optimise recruitment. RESULTS: Despite best intentions, oncologists' routine practices complicated recruitment. Discomfort about deviating from the usual practice of recommending chemotherapy according to tumour clinicopathological features meant that not all eligible patients were approached. Audio-recorded recruitment appointments revealed how routine practices undermined recruitment. A tendency to justify chemotherapy provision before presenting the randomised controlled trial and subtly indicating that chemotherapy would be more/less beneficial undermined equipoise and made it difficult for patients to engage with OPTIMA Prelim. To tackle these challenges, individual and group recruiter feedback focussed on communication issues and vignettes of eligible patients were discussed to address discomforts around approaching patients. 'Tips' documents concerning structuring discussions and conveying equipoise were disseminated across sites, together with revisions to the Patient Information Sheet. CONCLUSIONS: This is the first study illuminating the tension between oncologists' routine practices and recruitment to de-escalation trials. Although time and resources are required, these challenges can be addressed through specific feedback and training as the trial is underway.


Assuntos
Neoplasias da Mama/terapia , Comunicação , Tomada de Decisões , Pessoal de Saúde/psicologia , Seleção de Pacientes , Projetos de Pesquisa , Feminino , Humanos , Pesquisa Qualitativa , Ensaios Clínicos Controlados Aleatórios como Assunto
2.
Br J Cancer ; 116(7): 859-863, 2017 Mar 28.
Artigo em Inglês | MEDLINE | ID: mdl-28222072

RESUMO

BACKGROUND: There is limited data on results of central re-testing of samples from patients with invasive breast cancer categorised in their local hospital laboratories as oestrogen receptor (ER) positive and human epidermal growth factor receptor homologue 2 (HER2) negative. METHODS: The Optimal Personalised Treatment of early breast cancer usIng Multiparameter Analysis preliminary study (OPTIMA prelim) was the feasibility phase of a randomised controlled trial to validate the use of multiparameter assay-directed chemotherapy decisions in the UK National Health Service (NHS). Eligibility criteria included ER positivity and HER2 negativity. Central re-testing of receptor status was mandatory. RESULTS: Of the 431 patients tested centrally, discrepant results between central and local laboratory results were identified in only 19 (4.4%; 95% confidence interval 2.5-6.3%) patients (with 21 tumours). On central review, seven patients had cancers that were ER-negative (1.6%) and 13 (3.0%) patients with 15 tumours had HER2-positive disease, including one tumour discrepant for both biomarkers. CONCLUSIONS: Central re-testing of receptor status of invasive breast cancers in the UK NHS setting shows a high level of reproducibility in categorising tumours as ER-positive and HER2-negative, and raises questions regarding the cost effectiveness and clinical value of central re-testing in this sub-group of breast cancers in this setting.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Biomarcadores Tumorais/metabolismo , Neoplasias da Mama/metabolismo , Sistemas de Apoio a Decisões Clínicas/normas , Ciência de Laboratório Médico/métodos , Receptor ErbB-2/metabolismo , Receptores de Estrogênio/metabolismo , Adulto , Neoplasias da Mama/diagnóstico , Neoplasias da Mama/tratamento farmacológico , Quimioterapia Adjuvante , Estudos de Viabilidade , Feminino , Seguimentos , Humanos , Técnicas Imunoenzimáticas , Invasividade Neoplásica , Estadiamento de Neoplasias , Prognóstico , Reprodutibilidade dos Testes , Projetos de Pesquisa
3.
Eur J Surg Oncol ; 42(7): 994-8, 2016 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-27020141

RESUMO

The efficacy and pivotal role of the multidisciplinary meeting (MDM) in informed decision making is well established. It aims to provide a forum in which clinical evidence combines with individual patient data to create a personalized treatment plan. It does not fulfil this role adequately when undertaken without the full results of the patient's investigations being available. Neither doctor nor patient can make an informed decision about treatment options without knowledge of the tumour receptor status. Both targeted therapies and the aim to treat a majority of patients within clinical trials must now drive MDM decision making to be based on accuracy and best available treatment choices. A fully informed decision on treatment delayed by 1-2 weeks is clearly preferable to rushed time target-driven decisions made without the patient being offered a fully informed choice as ratified by a multidisciplinary team. Whilst the early anxiety of waiting for all relevant information to be available may be stressful for patients, not being sure that they have been offered fully informed treatment choices is also stressful and could cause longer lasting anxiety both during and after treatment. MDMs need to develop (along with targeted therapies) to retain their role as a forum whereby patients receive a correct, but specifically a full diagnosis and allow a fully informed discussion of all treatment options, including pre-operative clinical trials.


Assuntos
Biomarcadores Tumorais/análise , Neoplasias da Mama/química , Neoplasias da Mama/terapia , Tomada de Decisão Clínica , Equipe de Assistência ao Paciente , Receptor ErbB-2/análise , Receptores de Estrogênio/análise , Adulto , Idoso , Antineoplásicos/administração & dosagem , Neoplasias da Mama/economia , Quimioterapia Adjuvante , Ensaios Clínicos como Assunto/métodos , Ensaios Clínicos como Assunto/normas , Análise Custo-Benefício , Feminino , Humanos , Pessoa de Meia-Idade , Terapia Neoadjuvante/métodos , Equipe de Assistência ao Paciente/normas , Equipe de Assistência ao Paciente/tendências , Receptor ErbB-2/antagonistas & inibidores , Fatores de Tempo , Trastuzumab/administração & dosagem , Reino Unido
4.
Br J Cancer ; 110(8): 1950-7, 2014 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-24667651

RESUMO

BACKGROUND: The Biomarker Strategy Design has been proposed for trials assessing the value of a biomarker in guiding treatment in oncology. In such trials, patients are randomised to either receive the standard chemotherapy treatment or a biomarker-directed treatment arm, in which biomarker status is used to guide treatment. METHODS: Motivated by a current trial, we consider an adaptive design in which two biomarkers are assessed. The trial is conducted in two stages. In the first stage, patients in the biomarker-guided arm are assessed using a standard and an alternative cheaper biomarker, with the standard biomarker guiding treatment. An analysis comparing biomarker results is then used to choose the biomarker to use for the remainder of the trial. The new biomarker is used if the results for the two biomarkers are sufficiently similar. RESULTS: We show that in practical situations the first-stage results can be used to adapt the trial without type I error rate inflation. We also show that there can be considerable cost gains with only a small loss in power in the case where the alternative biomarker is highly concordant with the standard one. CONCLUSIONS: Adaptive designs have an important role in reducing the cost and increasing the clinical utility of trials evaluating biomarker-guided treatment strategies.


Assuntos
Neoplasias da Mama/tratamento farmacológico , Neoplasias da Mama/genética , Medicina de Precisão , Biomarcadores Tumorais/sangue , Neoplasias da Mama/sangue , Neoplasias da Mama/patologia , Simulação por Computador , Feminino , Humanos , Ensaios Clínicos Controlados Aleatórios como Assunto , Projetos de Pesquisa , Resultado do Tratamento
5.
J Clin Pathol ; 67(2): 161-7, 2014 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-24062360

RESUMO

Human epidermal growth factor receptor 2 (HER2) testing is required for newly diagnosed breast cancer and advised for recurrent and metastatic breast cancer, to determine treatment planning using HER2-directed therapy in the neoadjuvant, adjuvant and advanced disease settings. Wide variation, nationally, in the turnaround time for HER2 testing may hinder equity of access for patients to both clinical trials and the timely implementation of HER2-directed therapy particularly in the neo-adjuvant setting. Process mapping from three recognised laboratories in the UK was applied to the logistics of HER2 testing in different geographic hub and spoke models. Consequently, recommendations for HER2 testing likely to facilitate access to clinical trials and timely patient care are presented.


Assuntos
Neoplasias da Mama/genética , Laboratórios/normas , Ensaio de Proficiência Laboratorial/métodos , Receptor ErbB-2/genética , Feminino , Humanos , Imuno-Histoquímica/métodos , Imuno-Histoquímica/normas , Hibridização in Situ Fluorescente/métodos , Hibridização in Situ Fluorescente/normas , Receptor ErbB-2/análise
6.
Oncogene ; 28(46): 4041-52, 2009 Nov 19.
Artigo em Inglês | MEDLINE | ID: mdl-19802002

RESUMO

Neuregulin-1 (NRG1) is both a candidate oncogene and a candidate tumour suppressor gene. It not only encodes the heregulins and other mitogenic ligands for the ERBB family, but also causes apoptosis in NRG1-expressing cells. We found that most breast cancer cell lines had reduced or undetectable expression of NRG1. This included cell lines that had translocation breaks in the gene. Similarly, expression in cancers was generally comparable to or less than that in various normal breast samples. Many non-expressing cell lines had extensive methylation of the CpG island at the principal transcription start site at exon 2 of NRG1. Expression was reactivated by demethylation. Many tumours also showed methylation, whereas normal mammary epithelial fragments had none. Lower NRG1 expression correlated with higher methylation. Small interfering RNA (siRNA)-mediated depletion of NRG1 increased net proliferation in a normal breast cell line and a breast cancer cell line that expressed NRG1. The short arm of chromosome 8 is frequently lost in epithelial cancers, and NRG1 is the most centromeric gene that is always affected. NRG1 may therefore be the major tumour suppressor gene postulated to be on 8p: it is in the correct location, is antiproliferative and is silenced in many breast cancers.


Assuntos
Neoplasias da Mama/genética , Aberrações Cromossômicas , Cromossomos Humanos Par 8 , Metilação de DNA , Inativação Gênica , Genes Supressores de Tumor , Neuregulina-1/genética , Sequência de Bases , Neoplasias da Mama/patologia , Linhagem Celular Tumoral , Proliferação de Células , Mapeamento Cromossômico , Cromossomos Humanos Par 8/química , Cromossomos Humanos Par 8/genética , Ilhas de CpG/genética , Feminino , Regulação Neoplásica da Expressão Gênica , Predisposição Genética para Doença/genética , Humanos , Neuregulina-1/fisiologia , Sítio de Iniciação de Transcrição
7.
Br J Cancer ; 96(12): 1808-16, 2007 Jun 18.
Artigo em Inglês | MEDLINE | ID: mdl-17533402

RESUMO

Ovarian reserve can be diminished following treatment for breast cancer. This study evaluated biochemical and biophysical parameters of ovarian reserve in these patients. Biochemical and biophysical tests of ovarian reserve were performed simultaneously in young (age 22-42 years), regularly menstruating women with breast cancer (n=22) and age-matched controls (n=24). All tests were performed before (baseline) and after transient ovarian stimulation in the early follicular phase. Patients were recruited both before and after completion of chemotherapy, with some patients being followed up prospectively. Serum samples were analysed for follicle-stimulating hormone (FSH), luteinising hormone (LH), oestradiol (E(2)), inhibins A and B, and antimullerian hormone (AMH). Biophysical (ultrasound) tests included ovarian volume, antral follicle count (AFC), ovarian stromal blood flow and uterine dimensions. Significant differences were revealed (when compared with the controls) for basal FSH (11.32+/-1.48 vs 6.62+/-0.42 mIU ml(-1), P<0.001), basal AMH (0.95+/-0.34 vs 7.89+/-1.62 ng ml(-1), P<0.001) and basal inhibin B (19.24+/-4.56 vs 83.61+/-13.45 pg ml(-1), P<0.001). Following transient ovarian stimulation, there were significant differences in the increment change (Delta) for inhibin B (3.02+/-2.3 vs 96.82+/-16.38 pg ml(-1), P<0.001) and E(2) (107.8+/-23.95 vs 283.2+/-40.34 pg ml(-1), P<0.01). AFC was the only biophysical parameter that was significantly different between patients and the controls (7.80+/-0.85 vs 16.77+/-1.11, P<0.001). Basal and stimulated biochemical (serum AMH, FSH, inhibin B and E(2)) and biophysical (AFC) tests may be potential markers of ovarian reserve in young women with breast cancer.


Assuntos
Neoplasias da Mama/tratamento farmacológico , Testes de Função Ovariana , Ovário/fisiopatologia , Adulto , Antineoplásicos/efeitos adversos , Feminino , Humanos , Folículo Ovariano/efeitos dos fármacos , Folículo Ovariano/patologia , Ovário/efeitos dos fármacos
8.
Endocr Relat Cancer ; 8(3): 237-48, 2001 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-11566615

RESUMO

The phosphoinositide 3-kinases (PI3-kinases) are a family of lipid kinases that have a key role in the regulation of many cellular processes including proliferation, survival, carbohydrate metabolism, and motility. There is now strong evidence that some members of the PI3-kinase family have an important role in cancer. Emerging evidence for functional specialisation of PI3-kinase isoforms suggests that isoform selective inhibitors, in contrast to the existing non-selective inhibitors wortmannin and LY294002, may prove to be useful anticancer drugs.


Assuntos
Antineoplásicos/uso terapêutico , Inibidores Enzimáticos/uso terapêutico , Neoplasias/tratamento farmacológico , Inibidores de Fosfoinositídeo-3 Quinase , Animais , Humanos , Metabolismo dos Lipídeos , Neoplasias/enzimologia , Fosfatidilinositol 3-Quinases/metabolismo
9.
Br Homeopath J ; 89(4): 195-7, 2000 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-11055778

RESUMO

The biology, behaviour and venom of the ant Myrmecia nigrocincta are described. Symptoms of 15 cases of envenomation are described.


Assuntos
Venenos de Formiga/toxicidade , Formigas , Mordeduras e Picadas de Insetos/patologia , Adolescente , Adulto , Animais , Austrália , Criança , Pré-Escolar , Feminino , Humanos , Masculino , Pessoa de Meia-Idade
10.
Br. homoeopath. j ; 89(4): 195-7, oct. 2000. ilus
Artigo em Inglês | HomeoIndex - Homeopatia | ID: hom-5781

RESUMO

The biology, behaviour and venom of the ant Myrmecia nigrocincta are described. Symptoms of 15 cases of envenenomation are described. (AU)


Assuntos
Venenos de Formiga/toxicidade , Mordeduras e Picadas de Insetos , Toxicologia , Patogenesia Homeopática , Materia Medica , Austrália
11.
Mol Med Today ; 6(9): 347-57, 2000 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-10954868

RESUMO

The phosphoinositide 3-kinases (PI3-kinases) are a ubiquitously expressed enzyme family that, through the generation of phospholipid second messengers, play a key role in the regulation of many cellular processes. These include motility, proliferation and survival, and carbohydrate metabolism. Members of the PI3-kinase family and related kinases, their mechanism of activation and the cellular events that they influence are described in this review. As knowledge of their involvement in disease processes increases, the PI3-kinases appear to be an increasingly attractive target for drug development, particularly in the fields of cancer and other proliferative diseases, and in the treatment of inflammatory and immunological conditions. Evidence of the functional specialization of PI3-kinase isoforms suggests that selective inhibition with acceptable toxicity might be possible.


Assuntos
Inibidores Enzimáticos/uso terapêutico , Inibidores de Fosfoinositídeo-3 Quinase , Animais , Desenho de Fármacos , Humanos , Metabolismo dos Lipídeos , Fosfatidilinositol 3-Quinases/metabolismo , Transdução de Sinais/fisiologia
12.
Biochem J ; 348 Pt 2: 351-8, 2000 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-10816429

RESUMO

The proliferation of most normal cells depends on the co-operation of several growth factors and hormones, each with a specific role, but the key events involved in the action of each necessary stimulant remain largely uncharacterized. In the present study, the pathways involved in the mechanism(s) of co-operation have been investigated in primary cultures of dog thyroid epithelial cells. In this physiologically relevant system, thyroid stimulating hormone (TSH) acting through cAMP, epidermal growth factor (EGF) and phorbol esters (such as PMA) induce DNA synthesis. Their effect requires stimulation of the insulin-like growth factor-1 (IGF-1) receptor by either IGF-1 or insulin, which are not themselves mitogenic agents. In contrast, hepatocyte growth factor (HGF) is itself fully mitogenic. The results of the study demonstrate that cAMP, EGF, HGF and PMA stimulate p70 ribosomal S6 kinase (p70 S6 kinase). However, insulin/IGF-1 also stimulate p70 S6 kinase. Thus stimulation of p70 S6 kinase might be necessary, but is certainly not sufficient, for the induction of DNA synthesis and is not specific for any stimulated pathway. In contrast, phosphatidylinositol 3-kinase (PI 3-kinase) and protein kinase B (PKB) activation by insulin and HGF is strong and sustained, whereas it is weak and transient with EGF and absent in the presence of TSH or PMA. These findings suggest that: (i) stimulation of PI 3-kinases and/or PKB is not involved in the cAMP-dependent pathways leading to thyrocyte proliferation, or in the action of PMA, (ii) the stimulation of the PI 3-kinase/PKB pathway may account for the permissive action of insulin/IGF-1 in the proliferation of these cells, and (iii) the stimulation of this pathway by HGF may explain why this agent does not require insulin or IGF-1 for its mitogenic action.


Assuntos
Divisão Celular/efeitos dos fármacos , Colforsina/farmacologia , AMP Cíclico/fisiologia , Células Epiteliais/citologia , Células Epiteliais/fisiologia , Substâncias de Crescimento/farmacologia , Insulina/farmacologia , Fosfatidilinositol 3-Quinases/metabolismo , Proteínas Serina-Treonina Quinases , Proteínas Proto-Oncogênicas/metabolismo , Proteínas Quinases S6 Ribossômicas/metabolismo , Glândula Tireoide/citologia , Glândula Tireoide/fisiologia , Androstadienos/farmacologia , Animais , Células Cultivadas , Cães , Inibidores Enzimáticos/farmacologia , Fator de Crescimento Epidérmico/farmacologia , Células Epiteliais/efeitos dos fármacos , Fator de Crescimento de Hepatócito/farmacologia , Cinética , Fosfatidilinositóis/metabolismo , Proteínas Proto-Oncogênicas c-akt , Sirolimo/farmacologia , Acetato de Tetradecanoilforbol/farmacologia , Tireotropina/farmacologia , Wortmanina
13.
Proc Natl Acad Sci U S A ; 96(22): 12589-94, 1999 Oct 26.
Artigo em Inglês | MEDLINE | ID: mdl-10535966

RESUMO

Normal human luminal and myoepithelial breast cells separately purified from a set of 10 reduction mammoplasties by using a double antibody magnetic affinity cell sorting and Dynabead immunomagnetic technique were used in two-dimensional gel proteome studies. A total of 43,302 proteins were detected across the 20 samples, and a master image for each cell type comprising a total of 1,738 unique proteins was derived. Differential analysis identified 170 proteins that were elevated 2-fold or more between the two breast cell types, and 51 of these were annotated by tandem mass spectrometry. Muscle-specific enzyme isoforms and contractile intermediate filaments including tropomyosin and smooth muscle (SM22) alpha protein were detected in the myoepithelial cells, and a large number of cytokeratin subclasses and isoforms characteristic of luminal cells were detected in this cell type. A further 134 nondifferentially regulated proteins were also annotated from the two breast cell types, making this the most extensive study to date of the protein expression map of the normal human breast and the basis for future studies of purified breast cancer cells.


Assuntos
Mama/metabolismo , Proteoma/metabolismo , Adulto , Mama/citologia , Eletroforese em Gel Bidimensional , Células Epiteliais/metabolismo , Feminino , Humanos , Mamoplastia , Espectrometria de Massas , Pessoa de Meia-Idade
14.
J Nucl Med ; 39(10): 1743-5, 1998 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-9776280

RESUMO

UNLABELLED: Iodine-13I-metaiodobenzylguanidine (MIBG) is highly concentrated by >60% of carcinoid metastases and thus provides a therapeutic opportunity. METHODS: A symptomatic patient with carcinoid liver metastases, unresponsive to chemotherapy combined with interferon-alpha, was subsequently treated with 131I-MIBG. RESULTS: Radionuclide therapy, which was without significant side effects, resulted in symptomatic improvement and reduced urinary 5-hydroxyindoleacetic acid levels. No new metastases were observed for 15 mo after 131I-MIBG therapy. Gross cystic change occurred in existing liver metastases, presumably as a result of ischemic necrosis. Surgical deroofing and aspiration of cysts led to regeneration of normal liver tissue. CONCLUSION: Iodine-131-MIBG therapy can provide prolonged symptomatic relief and improved quality of life in patients with metastatic carcinoid disease unresponsive to other therapies. The antitumor effect of 131I-MIBG was accompanied by few side effects, suggesting that this therapy should be considered in symptomatic patients with an early stage of disease.


Assuntos
3-Iodobenzilguanidina/uso terapêutico , Antineoplásicos/uso terapêutico , Tumor Carcinoide/tratamento farmacológico , Tumor Carcinoide/secundário , Radioisótopos do Iodo/uso terapêutico , Neoplasias Hepáticas/tratamento farmacológico , Neoplasias Hepáticas/secundário , Feminino , Humanos , Pessoa de Meia-Idade
15.
J Mol Biol ; 276(2): 461-78, 1998 Feb 20.
Artigo em Inglês | MEDLINE | ID: mdl-9512716

RESUMO

Heterodimeric class IA phosphoinositide 3-kinase (PI 3-kinase) plays a crucial role in a variety of cellular signalling events downstream of a number of cell-surface receptor tyrosine kinases. Activation of the enzyme is effected in part by the binding of two Src homology-2 domains (SH2) of the 85 kDa regulatory subunit to specific phosphotyrosine-containing peptide motifs within activated cytoplasmic receptor domains. The solution structure of the uncomplexed C-terminal SH2 (C-SH2) domain of the p85 alpha subunit of PI 3-kinase has been determined by means of multinuclear, double and triple-resonance NMR experiments and restrained molecular-dynamics simulated-annealing calculations. The solution structure clearly indicates that the uncomplexed C-SH2 domain conforms to the consensus polypeptide fold exhibited by other SH2 domains, with an additional short helical element at the N terminus. In particular, the C-SH2 structure is very similar to both the p85 alpha N-terminal SH2 domain (N-SH2) and the Src SH2 domain with a root mean square difference (rmsd) for 44 C alpha atoms of 1.09 and 0.89 A, respectively. The canonical BC, EF and BG loops are less well-defined by the experimental restraints and show greater variability in the ensemble of C-SH2 conformers. The lower level of definition in these regions may reflect the presence of conformational disorder, an interpretation supported by the absence or broadening of backbone and side-chain NMR resonances for some of these residues. NMR experiments were performed, where C-SH2 was titrated with phosphotyrosine-containing peptides corresponding to p85 alpha recognition sites in the cytoplasmic domain of the platelet-derived growth-factor receptor. The ligand-induced chemical-shift perturbations indicate the amino-acid residues in C-SH2 involved in peptide recognition follow the pattern predicted from homologous complexes. A series of C-SH2 mutants was generated and tested for phosphotyrosine peptide binding by surface plasmon resonance. Mutation of the invariant Arg36 (beta B5) to Met completely abolishes phosphopeptide binding. Mutation of each of Ser38, Ser39 or Lys40 in the BC loop to Ala reduces the affinity of C-SH2 for a cognate phosphopeptide, as does mutation of His93 (BG5) to Asn. These effects are consistent with the involvement of the BC loop and BG loops regions in ligation of phosphopeptide ligands. Mutation of Cys57 (beta D5) in C-SH2 to Ile, the corresponding residue type in the p85 alpha N-SH2 domain, results in a change in peptide binding selectivity of C-SH2 towards that demonstrated by p85 alpha N-SH2. This pattern of p85 alpha phosphopeptide binding specificity is interpreted in terms of a model of the p85 alpha/PDGF-receptor interaction.


Assuntos
Fosfatidilinositol 3-Quinases/química , Fosfatidilinositol 3-Quinases/metabolismo , Domínios de Homologia de src , Sequência de Aminoácidos , Glutationa Transferase/química , Glutationa Transferase/genética , Glutationa Transferase/metabolismo , Espectroscopia de Ressonância Magnética/métodos , Modelos Moleculares , Dados de Sequência Molecular , Mutagênese , Fragmentos de Peptídeos/química , Fragmentos de Peptídeos/metabolismo , Fosfoproteínas/química , Fosfoproteínas/metabolismo , Conformação Proteica , Receptores do Fator de Crescimento Derivado de Plaquetas/química , Receptores do Fator de Crescimento Derivado de Plaquetas/metabolismo , Proteínas Recombinantes de Fusão/química , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/metabolismo , Homologia de Sequência de Aminoácidos , Soluções
16.
Biochem J ; 326 ( Pt 1): 139-47, 1997 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-9337861

RESUMO

The generation of phosphatidylinositide 3-phosphates has been observed in a variety of cellular responses. The enzymes that mediate synthesis are the phosphoinositide 3-kinases (PI3-Ks) that form a family of structurally diverse enzymes with distinct substrate specificities. In this paper, we describe the cloning of a novel human PI3-K, namely PI3-K-C2 alpha, which contains a C-terminal C2 domain. This enzyme can be assigned to the class II PI3-Ks, which was defined by characterization of the Drosophila 68D enzyme and includes the recently described murine enzymes m-cpk and p170. Despite the overall similarity in the amino acid sequence of the murine and human enzymes, which suggests that they are encoded by closely related genes, these molecules show marked sequence heterogeneity at their N-termini. Biochemical analysis of recombinant PI3-K-C2 alpha demonstrates a restricted lipid substrate specificity. As reported for other members of this class, the enzyme only phosphorylates PtdIns and PtdIns4P when the lipids are presented alone. However, when lipids were presented together with phosphatidylserine acting as a carrier, phosphorylation of PtdIns(4,5)P2 was also observed. The catalytic activity of PI3-K-C2 alpha is refractory to concentrations of wortmannin and LY294002 which inhibit the PI3-K activity of other family members. The comparative insensitivity of PI3-K-C2 alpha to these inhibitors suggests that their use should be reevaluated in the study of PI3-Ks.


Assuntos
Androstadienos/farmacologia , Fosfatidilinositol 3-Quinases/genética , Inibidores de Fosfoinositídeo-3 Quinase , Sequência de Aminoácidos , Animais , Sequência de Bases , Clonagem Molecular , Humanos , Metabolismo dos Lipídeos , Camundongos , Dados de Sequência Molecular , Especificidade de Órgãos/genética , Fosfatidilinositol 3-Quinases/biossíntese , Fosfatidilinositol 3-Quinases/química , Fosforilação , Estrutura Terciária de Proteína , Especificidade por Substrato , Células Tumorais Cultivadas , Wortmanina
17.
Cancer Surv ; 27: 249-70, 1996.
Artigo em Inglês | MEDLINE | ID: mdl-8909804

RESUMO

Phosphoinositide 3-kinases catalyze the addition of phosphate at the 3-OH position of inositol lipids in cellular membranes. Initially identified as an enzymatic activity associated with transforming oncogenic proteins, PI3-kinases are now known to be involved in signal transduction through receptors with intrinsic or associated tyrosine kinase activity (such as sre type tyrosine kinases) and receptors linked to heterotrimeric G proteins. PI3-kinases also have a role in vesicular trafficking events. PI3-kinases form a large family of related proteins, conserved in organisms as distant as yeast and man. The exact role of their lipid products remains to be established, but the multiplicity of cellular events in which PI3-kinases are implicated, together with their conservation in evolution, indicates that they fulfil an essential role in cellular physiology.


Assuntos
Fosfotransferases (Aceptor do Grupo Álcool)/fisiologia , Animais , Humanos , Fosfatidilinositol 3-Quinases , Transdução de Sinais/fisiologia
19.
Eur J Cancer ; 29A(3): 316-9, 1993.
Artigo em Inglês | MEDLINE | ID: mdl-8398325

RESUMO

Malignant pleural effusion is a frequent complication of metastatic breast cancer leading to a significant degree of morbidity. Drainage of the effusion by thoracocentesis and pleurodesis with tetracycline as the sclerosing agent is an established means of symptomatic relief in these patients. To determine whether the efficacy of tetracycline pleurodesis is improved by surgical rather than medical drainage and instillation of sclerosant, 34 patients were prospectively randomised to a trial comparing the two treatment modalities, of whom 29 were evaluable for response. The total failure rate of primary pleurodesis was 13.4%, the rate of recurrence of effusion within the first month was 24%, and only 1 patient (3.4%) required repeat aspiration in that time period. There was no significant difference in the rate of recurrence or reaspiration of effusion between the two treatment groups. Although the overall survival time from treatment of effusion is significantly longer in the surgical treatment group than in the medical treatment group (P = 0.03), this is likely to be due to factors other than the method of treating the effusion. We conclude that surgical tetracycline pleurodesis has no advantage over medical tetracycline pleurodesis.


Assuntos
Neoplasias da Mama/complicações , Derrame Pleural Maligno/tratamento farmacológico , Derrame Pleural Maligno/cirurgia , Tetraciclina/uso terapêutico , Adulto , Idoso , Neoplasias da Mama/mortalidade , Drenagem , Feminino , Humanos , Pessoa de Meia-Idade , Prognóstico , Estudos Prospectivos , Fatores de Tempo
20.
J Steroid Biochem Mol Biol ; 43(1-3): 155-9, 1992 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-1388047

RESUMO

Aromatase inhibition in postmenopausal women causes a marked fall in the plasma levels of oestrogens and is an effective treatment for breast cancer, however, trials with aminoglutethimide found that this aromatase inhibitor was ineffective in suppressing plasma oestrogen levels in premenopausal breast cancer patients. We found that the more potent inhibitor, 4-hydroxyandrostenedione (4-OHA), which can suppress oestrogen synthesis in rodents and non-human primates with intact ovarian function, was also unsuccessful as an oestrogen suppressant in premenopausal women at its maximum tolerated dose (500 mg/week i.m.). GnRH agonists are effective suppressants of ovarian oestrogen synthesis but oestrogen production from peripheral sites is unaffected. Our studies of a combination of the GnRH agonist goserelin and 4-OHA demonstrated that the combination caused greater oestrogen suppression than goserelin alone and led to objective clinical response in 4/6 breast cancer patients after their relapse from treatment with goserelin as a single agent. The combination of a GnRH agonist and an aromatase inhibitor should be subjected to clinical trials.


Assuntos
Androstenodiona/análogos & derivados , Antineoplásicos/uso terapêutico , Inibidores da Aromatase , Neoplasias da Mama/tratamento farmacológico , Androstenodiona/uso terapêutico , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Busserrelina/administração & dosagem , Busserrelina/análogos & derivados , Estrogênios/sangue , Feminino , Gosserrelina , Humanos , Menopausa
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...