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1.
J Mater Chem B ; 6(4): 550-555, 2018 Jan 28.
Artigo em Inglês | MEDLINE | ID: mdl-32254483

RESUMO

The short shelf-life of water-soluble quantum dots (QDs) due to colloidal instability represents a major drawback to their exploitation. This work examines the colloidal stability of PbS nanoparticles capped with dihydrolipoic acid-polyethylene glycol (DHLA-PEG) ligands terminated with functional groups such as -NH2, -COOH, OMe and -N3. and their application for in vivo imaging. We prove a mechanism of colloidal instability and develop a strategy to produce for the first time stable PEG-capped PbS quantum dots with high quantum yield and optical emission in the first and the second near-infrared (NIR) windows of low absorption of biological tissues. The NIR imaging of in vivo biodistribution is demonstrated at wavelengths >1000 nm, with benefits of reduced tissue absorption and light scattering. The stability, biocompatibility and potential for further QD functionalization open up realistic prospects for non-invasive bioimaging applications.

2.
Blood Cancer J ; 7(3): e549, 2017 03 31.
Artigo em Inglês | MEDLINE | ID: mdl-28362441

RESUMO

Myeloma is heterogeneous at the molecular level with subgroups of patients characterised by features of epigenetic dysregulation. Outcomes for myeloma patients have improved over the past few decades except for molecularly defined high-risk patients who continue to do badly. Novel therapeutic approaches are, therefore, required. A growing number of epigenetic inhibitors are now available including EZH2 inhibitors that are in early-stage clinical trials for treatment of haematological and other cancers with EZH2 mutations or in which overexpression has been correlated with poor outcomes. For the first time, we have identified and validated a robust and independent deleterious effect of high EZH2 expression on outcomes in myeloma patients. Using two chemically distinct small-molecule inhibitors, we demonstrate a reduction in myeloma cell proliferation with EZH2 inhibition, which leads to cell cycle arrest followed by apoptosis. This is mediated via upregulation of cyclin-dependent kinase inhibitors associated with removal of the inhibitory H3K27me3 mark at their gene loci. Our results suggest that EZH2 inhibition may be a potential therapeutic strategy for the treatment of myeloma and should be investigated in clinical studies.


Assuntos
Pontos de Checagem do Ciclo Celular/genética , Proteína Potenciadora do Homólogo 2 de Zeste/genética , Expressão Gênica , Mieloma Múltiplo/genética , Mieloma Múltiplo/mortalidade , Apoptose/genética , Biomarcadores , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/genética , Proteína Potenciadora do Homólogo 2 de Zeste/antagonistas & inibidores , Epigênese Genética , Perfilação da Expressão Gênica , Histonas/metabolismo , Humanos , Estimativa de Kaplan-Meier , Células-Tronco Mesenquimais/metabolismo , Mieloma Múltiplo/diagnóstico , Mieloma Múltiplo/terapia , Fenótipo , Prognóstico , Modelos de Riscos Proporcionais , RNA Mensageiro/genética
3.
Sci Total Environ ; 534: 173-84, 2015 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-25957785

RESUMO

Mitigating the environmental effects of global population growth, climatic change and increasing socio-ecological complexity is a daunting challenge. To tackle this requires synthesis: the integration of disparate information to generate novel insights from heterogeneous, complex situations where there are diverse perspectives. Since 1995, a structured approach to inter-, multi- and trans-disciplinary(1) collaboration around big science questions has been supported through synthesis centres around the world. These centres are finding an expanding role due to ever-accumulating data and the need for more and better opportunities to develop transdisciplinary and holistic approaches to solve real-world problems. The Australian Centre for Ecological Analysis and Synthesis (ACEAS ) has been the pioneering ecosystem science synthesis centre in the Southern Hemisphere. Such centres provide analysis and synthesis opportunities for time-pressed scientists, policy-makers and managers. They provide the scientific and organisational environs for virtual and face-to-face engagement, impetus for integration, data and methodological support, and innovative ways to deliver synthesis products. We detail the contribution, role and value of synthesis using ACEAS to exemplify the capacity for synthesis centres to facilitate trans-organisational, transdisciplinary synthesis. We compare ACEAS to other international synthesis centres, and describe how it facilitated project teams and its objective of linking natural resource science to policy to management. Scientists and managers were brought together to actively collaborate in multi-institutional, cross-sectoral and transdisciplinary research on contemporary ecological problems. The teams analysed, integrated and synthesised existing data to co-develop solution-oriented publications and management recommendations that might otherwise not have been produced. We identify key outcomes of some ACEAS working groups which used synthesis to tackle important ecosystem challenges. We also examine the barriers and enablers to synthesis, so that risks can be minimised and successful outcomes maximised. We argue that synthesis centres have a crucial role in developing, communicating and using synthetic transdisciplinary research.


Assuntos
Conservação dos Recursos Naturais/métodos , Ecologia , Política Ambiental , Austrália , Comportamento Cooperativo , Ecossistema , Monitoramento Ambiental , Comunicação Interdisciplinar
4.
Oncogene ; 34(1): 15-26, 2015 Jan 02.
Artigo em Inglês | MEDLINE | ID: mdl-24292678

RESUMO

The HSP90 molecular chaperone plays a key role in the maturation, stability and activation of its clients, including many oncogenic proteins. Kinases are a substantial and important subset of clients requiring the key cochaperone CDC37. We sought an improved understanding of protein kinase chaperoning by CDC37 in cancer cells. CDC37 overexpression in human colon cancer cells increased CDK4 protein levels, which was negated upon CDC37 knockdown. Overexpressing CDC37 increased CDK4 protein half-life and enhanced binding of HSP90 to CDK4, consistent with CDC37 promoting kinase loading onto chaperone complexes. Against expectation, expression of C-terminus-truncated CDC37 (ΔC-CDC37) that lacks HSP90 binding capacity did not affect kinase client expression or activity; moreover, as with wild-type CDC37 overexpression, it augmented CDK4-HSP90 complex formation. However, although truncation blocked binding to HSP90 in cells, ΔC-CDC37 also showed diminished client protein binding and was relatively unstable. CDC37 mutants with single and double point mutations at residues M164 and L205 showed greatly reduced binding to HSP90, but retained association with client kinases. Surprisingly, these mutants phenocopied wild-type CDC37 overexpression by increasing CDK4-HSP90 association and CDK4 protein levels in cells. Furthermore, expression of the mutants was sufficient to protect kinase clients CDK4, CDK6, CRAF and ERBB2 from depletion induced by silencing endogenous CDC37, indicating that CDC37's client stabilising function cannot be inactivated by substantially reducing its direct interaction with HSP90. However, CDC37 could not compensate for loss of HSP90 function, showing that CDC37 and HSP90 have their own distinct and non-redundant roles in maintaining kinase clients. Our data substantiate the important function of CDC37 in chaperoning protein kinases. Furthermore, we demonstrate that CDC37 can stabilise kinase clients by a mechanism that is not dependent on a substantial direct interaction between CDC37 and HSP90, but nevertheless requires HSP90 activity. These results have significant implications for therapeutic targeting of CDC37.


Assuntos
Proteínas de Ciclo Celular/metabolismo , Chaperoninas/metabolismo , Neoplasias do Colo/metabolismo , Proteínas de Choque Térmico HSP90/metabolismo , Linhagem Celular Tumoral , Quinase 4 Dependente de Ciclina/metabolismo , Quinase 6 Dependente de Ciclina/metabolismo , Regulação Neoplásica da Expressão Gênica , Células HCT116 , Humanos , Mutação , Mutação Puntual , Ligação Proteica , Proteínas Proto-Oncogênicas c-raf/metabolismo , RNA Interferente Pequeno/metabolismo , Receptor ErbB-2/metabolismo
5.
Ann R Coll Surg Engl ; 96(7): 495-501, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-25245726

RESUMO

INTRODUCTION: The median survival of patients with glioblastoma multiforme (astrocytoma grade 4) remains less than 18 months despite radical surgery, radiotherapy and systemic chemotherapy. Surgical implantation of chemotherapy eluting wafers into the resection cavity has been shown to improve length of survival but the current licensed therapy has several drawbacks. This paper investigates in vivo efficacy of a novel drug eluting paste in glioblastoma. METHODS: Poly(lactic-co-glycolic acid)/poly(ethylene glycol) (PLGA/PEG) self-sintering paste was loaded with the chemotherapeutic agent etoposide and delivered surgically into partially resected tumours in a flank murine glioblastoma xenograft model. RESULTS: Surgical delivery of the paste was successful and practical, with no toxicity or surgical morbidity to the animals. The paste was retained in the tumour cavity, and preliminary results suggest a useful antitumour and antiangiogenic effect, particularly at higher doses. Bioluminescent imaging was not affected significantly by the presence of the paste in the tumour. CONCLUSIONS: Chemotherapy loaded PLGA/PEG paste seems to be a promising technology capable of delivering active drugs into partially resected tumours. The preliminary results of this study suggest efficacy with no toxicity and will lead to larger scale efficacy studies in orthotopic glioblastoma models.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/administração & dosagem , Neoplasias Encefálicas/tratamento farmacológico , Sistemas de Liberação de Medicamentos , Glioblastoma/tratamento farmacológico , Ácido Láctico/administração & dosagem , Ácido Poliglicólico/administração & dosagem , Carga Tumoral/efeitos dos fármacos , Animais , Biópsia por Agulha , Neoplasias Encefálicas/patologia , Neoplasias Encefálicas/cirurgia , Modelos Animais de Doenças , Glioblastoma/patologia , Glioblastoma/cirurgia , Humanos , Imuno-Histoquímica , Medições Luminescentes , Masculino , Camundongos , Camundongos Nus , Copolímero de Ácido Poliláctico e Ácido Poliglicólico , Resultado do Tratamento , Ensaios Antitumorais Modelo de Xenoenxerto
6.
Clin Pharmacol Ther ; 93(3): 252-9, 2013 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-23361103

RESUMO

The progressive elucidation of the molecular pathogenesis of cancer has fueled the rational development of targeted drugs for patient populations stratified by genetic characteristics. Here we discuss general challenges relating to molecular diagnostics and describe predictive biomarkers for personalized cancer medicine. We also highlight resistance mechanisms for epidermal growth factor receptor (EGFR) kinase inhibitors in lung cancer. We envisage a future requiring the use of longitudinal genome sequencing and other omics technologies alongside combinatorial treatment to overcome cellular and molecular heterogeneity and prevent resistance caused by clonal evolution.


Assuntos
Biomarcadores Tumorais/análise , Resistencia a Medicamentos Antineoplásicos , Oncologia , Neoplasias/tratamento farmacológico , Patologia Molecular , Medicina de Precisão , Humanos , Inibidores de Proteínas Quinases/uso terapêutico , Proteínas Proto-Oncogênicas B-raf/antagonistas & inibidores
7.
Curr Med Chem ; 18(18): 2686-714, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-21649578

RESUMO

The phosphoinositide 3-kinases (PI3Ks) constitute an important family of lipid kinase enzymes that control a range of cellular processes through their regulation of a network of signal transduction pathways, and have emerged as important therapeutic targets in the context of cancer, inflammation and cardiovascular diseases. Since the mid-late 1990s, considerable progress has been made in the discovery and development of small molecule ATP-competitive PI3K inhibitors, a number of which have entered early phase human trials over recent years from which key clinical results are now being disclosed. This review summarizes progress made to date, primarily on the discovery and characterization of class I and dual class I/IV subtype inhibitors, together with advances that have been made in translational and clinical research, notably in cancer.


Assuntos
Doenças Cardiovasculares/tratamento farmacológico , Classe I de Fosfatidilinositol 3-Quinases/antagonistas & inibidores , Medicina Clínica/métodos , Inflamação/tratamento farmacológico , Neoplasias/tratamento farmacológico , Inibidores de Proteínas Quinases/uso terapêutico , Doenças Cardiovasculares/enzimologia , Classe I de Fosfatidilinositol 3-Quinases/metabolismo , Medicina Clínica/tendências , Humanos , Inflamação/enzimologia , Neoplasias/enzimologia , Inibidores de Proteínas Quinases/farmacologia
9.
Anaesthesia ; 64(5): 555-62, 2009 May.
Artigo em Inglês | MEDLINE | ID: mdl-19413827

RESUMO

We studied the LMA Supreme in 100 elective, anaesthetised, healthy patients assessing: ease of use, airway quality, anatomical and functional positioning, airway leak and complications. Insertion was successful on first, second or third attempt in 90, nine and one patient respectively. Thirty manipulations were required in 22 patients to achieve a clear airway. Median [interquartile (range)] insertion time was 18 [10-25 (5-120)] s. During ventilation, an expired tidal volume of 7 ml x kg(-1) was achieved in all patients. Median [interquartile (range)] airway leak pressure was 24 [20-28 (13-40)] cmH(2)O. On fibreoptic examination via the device, vocal cords were visible in 83 patients (85%). During maintenance, five patients (5%) required 13 airway manipulations. There was one episode of minor regurgitation, without aspiration. Other complications and patient side-effects were mild and few. The LMA Supreme is easily and rapidly inserted, providing a reliable airway and good airway seal. Further studies are indicated to assess safety and performance compared to other supraglottic airway devices.


Assuntos
Máscaras Laríngeas , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Desenho de Equipamento , Feminino , Tecnologia de Fibra Óptica , Humanos , Intubação Intratraqueal/efeitos adversos , Intubação Intratraqueal/métodos , Máscaras Laríngeas/efeitos adversos , Masculino , Pessoa de Meia-Idade , Respiração Artificial , Volume de Ventilação Pulmonar , Fatores de Tempo , Adulto Jovem
10.
Oncogene ; 28(2): 157-69, 2009 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-18931700

RESUMO

The cochaperone CDC37 promotes the association of HSP90 with the protein kinase subset of client proteins to maintain their stability and signalling functions. HSP90 inhibitors induce depletion of clients, which include several oncogenic kinases. We hypothesized that the targeting of CDC37 using siRNAs would compromise the maturation of these clients and increase the sensitivity of cancer cells to HSP90 inhibitors. Here, we show that silencing of CDC37 in human colon cancer cells diminished the association of kinase clients with HSP90 and reduced levels of the clients ERBB2, CRAF, CDK4 and CDK6, as well as phosphorylated AKT. CDC37 silencing promoted the proteasome-mediated degradation of kinase clients, suggesting a degradation pathway independent from HSP90 binding. Decreased cell signalling through kinase clients was also demonstrated by reduced phosphorylation of downstream substrates and colon cancer cell proliferation was subsequently reduced by the inhibition of the G1/S-phase transition. Furthermore, combining CDC37 silencing with the HSP90 inhibitor 17-AAG induced more extensive and sustained depletion of kinase clients and potentiated cell cycle arrest and apoptosis. These results support an essential role for CDC37 in concert with HSP90 in maintaining oncogenic protein kinase clients and endorse the therapeutic potential of targeting CDC37 in cancer.


Assuntos
Adenocarcinoma/patologia , Neoplasias da Mama/patologia , Proteínas de Ciclo Celular/fisiologia , Chaperoninas/fisiologia , Neoplasias do Colo/patologia , Proteínas de Choque Térmico HSP90/fisiologia , Proteínas de Neoplasias/fisiologia , Neoplasias da Próstata/patologia , Proteínas Quinases/metabolismo , Interferência de RNA , RNA Interferente Pequeno/farmacologia , Adenocarcinoma/metabolismo , Apoptose/efeitos dos fármacos , Benzoquinonas/farmacologia , Neoplasias da Mama/metabolismo , Proteínas de Ciclo Celular/antagonistas & inibidores , Proteínas de Ciclo Celular/genética , Divisão Celular/efeitos dos fármacos , Linhagem Celular Tumoral/efeitos dos fármacos , Linhagem Celular Tumoral/metabolismo , Chaperoninas/antagonistas & inibidores , Chaperoninas/genética , Neoplasias do Colo/metabolismo , Feminino , Fase G1/efeitos dos fármacos , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Marcação de Genes , Proteínas de Choque Térmico HSP90/antagonistas & inibidores , Humanos , Lactamas Macrocíclicas/farmacologia , Masculino , Proteínas de Neoplasias/antagonistas & inibidores , Proteínas de Neoplasias/genética , Fosforilação/efeitos dos fármacos , Neoplasias da Próstata/metabolismo , Complexo de Endopeptidases do Proteassoma/metabolismo , Processamento de Proteína Pós-Traducional/efeitos dos fármacos , Pirazóis/farmacologia , Transdução de Sinais/efeitos dos fármacos
11.
Br J Cancer ; 96(12): 1855-61, 2007 Jun 18.
Artigo em Inglês | MEDLINE | ID: mdl-17505514

RESUMO

This study investigated sonic hedgehog (Shh) signalling in gastric metaplasia in the insulin-gastrin (InsGas) hypergastrinaemic mouse +/- Helicobacter felis (H. felis) infection. Sonic hedgehog gene and protein expression was reduced in pre-metaplastic lesions from non-infected mice (90% gene reduction, P<0.01) compared to normal mucosa. Sonic hedgehog was reactivated in gastric metaplasia of H. felis-infected mice (3.5-fold increase, P<0.01) compared to pre-metaplastic lesions. Additionally, the Shh target gene, glioma-associated oncogene (Gli)-1, was significantly reduced in the gastric glands of InsGas mice (75% reduction, P<0.05) and reactivated with H. felis infection (P<0.05, base of glands, P<0.01 stroma of metaplastic glands). The ability of H. felis to activate the Shh pathway was investigated by measuring the effect of target cytokine, interleukin-8 (IL-8), on Shh expression in AGS and MGLVA1 cells, which was shown to induce Shh expression at physiological concentrations. H. felis induced the expression of NF-kappaB in inflammatory infiltrates in vivo, and the expression of the IL-8 mouse homologue, protein KC, in inflammatory infiltrates and metaplastic lesions. Sonic hedgehog pathway reactivation was paralleled with an increase in proliferation of metaplastic lesions (15.75 vs 4.39% in infected vs non-infected mice, respectively, P<0.001). Furthermore, Shh overexpression increased the growth rate of the gastric cancer cell line, AGS. The antiapoptotic protein, bcl-2, was expressed in the stroma of infected mice, along with a second Shh target gene, patched-1 (P=0.0001, stroma of metaplastic gland). This study provides evidence suggesting reactivation of Shh signalling from pre-metaplastic to advanced metaplastic lesions of the stomach and outlines the importance of the Shh pathway as a potential chemoprophylactic target for gastric carcinogenesis.


Assuntos
Proteínas Hedgehog/genética , Adenocarcinoma , Animais , Linhagem Celular Tumoral , Mucosa Gástrica/patologia , Regulação Neoplásica da Expressão Gênica , Humanos , Camundongos , Camundongos Endogâmicos , Neoplasias Experimentais/genética , Neoplasias Experimentais/patologia , Reação em Cadeia da Polimerase , Lesões Pré-Cancerosas/genética , Lesões Pré-Cancerosas/patologia , Neoplasias Gástricas/genética , Neoplasias Gástricas/patologia
12.
Eur J Surg Oncol ; 33(5): 561-8, 2007 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-17254742

RESUMO

BACKGROUND: The role of androgen receptors (ARs) in tumorigenesis, including transcription of fibroblast growth factors (FGFs), is established in prostate cancer. This study examined the role of ARs and FGFs in oesophageal adenocarcinoma (EAC), where tumour incidence in males is higher. METHODS: AR gene expression was analysed using quantitative RT-PCR; AR, fibroblast growth factor receptor-1 (FGFR-1) and fibroblast growth factor-8 isoform b (FGF-8b) protein by immunohistochemistry; and serum steroid levels (testosterone, progesterone, luteinising hormone and follicle stimulating hormone (FSH)) by immunoassay. A human oesophageal adenocarcinoma cell line was grown subcutaneously in nude mice. RESULTS: AR gene expression was of significantly higher levels than oesophageal adenocarcinomas (n=21, p=0.002) and in the squamous carcinoma line (OE21) compared with the adenocarcinoma lines (OE33 and OE19). Median serum testosterone levels in oesophageal carcinoma patients were higher than in age-matched controls (p=0.01) and reduced postoperatively, in patients undergoing curative resection (p=0.006). No significant differences were observed in hormones except FSH, where preoperative levels were significantly higher in the EAC group. AR protein was expressed in normal oesophageal squamous epithelial cells and also in the stroma of 18/23 EAC samples. FGFR-1 protein was expressed in malignant epithelium of 23/23 tumour samples. OE19 xenografts grew faster in male versus female mice (tumour weight at day 21, 1.14 g and 0.28 g, respectively, p=0.005) and had elevated FGF receptor expression. CONCLUSIONS: AR expressed in the stroma of oesophageal adenocarcinomas may induce paracrine effects following stimulation by androgens (including tumour-derived), possibly via FGFs, including FGF-8b.


Assuntos
Adenocarcinoma/metabolismo , Neoplasias Esofágicas/metabolismo , Receptores Androgênicos/metabolismo , Animais , Feminino , Fator 8 de Crescimento de Fibroblasto/metabolismo , Expressão Gênica , Hormônios Esteroides Gonadais/sangue , Humanos , Masculino , Camundongos , Camundongos Nus , Transplante de Neoplasias , Receptores de Fatores de Crescimento de Fibroblastos/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Transplante Heterólogo , Células Tumorais Cultivadas
13.
Br J Cancer ; 91(8): 1614-23, 2004 Oct 18.
Artigo em Inglês | MEDLINE | ID: mdl-15452549

RESUMO

The detailed molecular basis and determinants of in vivo tumour sensitivity to conventional anticancer agents remain unclear. We examined the cellular and molecular consequences of cisplatin treatment using two ovarian tumour xenograft models that had not been previously adapted to culture in vitro. Both xenografts were curable with clinically relevant multiple doses of cisplatin. Following a single dose of cisplatin (6 mg kg(-1) i.p.) growth delays of 25 and 75 days were obtained for pxn100 and pxn65, respectively. This difference in response was not due to differences in DNA damage. Pxn100 tumours had a functional p53 response and a wild-type p53 sequence, whereas pxn65 harboured a mutant p53 and lacked a functional p53 response. Microarray analysis revealed the induction of p53-regulated genes and regulators of checkpoint control and apoptosis in pxn100 tumours following cisplatin-treatment. By contrast, there was no p53-dependent response and only limited changes in gene expression were detected in the pxn65 tumours. TUNEL analysis demonstrated high levels of apoptosis in the pxn100 tumours following cisplatin treatment, but there was no detectable apoptosis in the pxn65 tumours. Our observations show that a marked in vivo response to cisplatin can occur via p53-dependent apoptosis or independently of p53 status in human ovarian xenografts.


Assuntos
Antineoplásicos/uso terapêutico , Apoptose/efeitos dos fármacos , Cisplatino/uso terapêutico , Neoplasias Ovarianas/tratamento farmacológico , Neoplasias Ovarianas/metabolismo , Proteína Supressora de Tumor p53/metabolismo , Adenocarcinoma/tratamento farmacológico , Adenocarcinoma/metabolismo , Adenocarcinoma/patologia , Animais , Ciclo Celular , Adutos de DNA , Dano ao DNA , Modelos Animais de Doenças , Tumor do Seio Endodérmico/tratamento farmacológico , Tumor do Seio Endodérmico/metabolismo , Tumor do Seio Endodérmico/patologia , Feminino , Perfilação da Expressão Gênica , Humanos , Marcação In Situ das Extremidades Cortadas , Camundongos , Camundongos Nus , Mutação , Análise de Sequência com Séries de Oligonucleotídeos , Neoplasias Ovarianas/patologia , Transplante Heterólogo , Proteína Supressora de Tumor p53/genética
14.
Br J Cancer ; 87(5): 567-73, 2002 Aug 27.
Artigo em Inglês | MEDLINE | ID: mdl-12189558

RESUMO

The role of hyper-gastrinaemia in the incidence of colonic cancer remains to be clarified. The aim of this study was to determine whether cholecystokinin-2 (CCK-2) receptor expression predicts the sensitivity of human colonic adenomas to the proliferative effects of serum hyper-gastrinaemia. Gene expression of the classical (74 kDa) CCK-2 receptor in human colonic adenoma specimens and cell lines, was quantified by real-time PCR. Western blotting, using a CCK-2 receptor antiserum, confirmed protein expression. A transformed human colonic adenoma was grown in SCID mice, with hyper-gastrinaemia induced by proton pump inhibitors. CCK-2 receptor blockade was achieved by using neutralising antiserum. Both human colonic adenoma cell lines and biopsies expressed CCK-2 receptor mRNA at levels comparable with CCK-2 receptor transfected fibroblasts and oxyntic mucosa. Western blotting confirmed immunoreactive CCK-2 receptor bands localised to 45, 74 and 82.5 kDa. Omeprazole and lansoprazole-induced hyper-gastrinaemia (resulting in serum gastrin levels of 34.0 and 153.0 pM, respectively) significantly increased the weight of the human adenoma grafts (43% (P=0.016) and 70% (P=0.014), respectively). The effect of hypergastrinaemia on tumour growth was reversed by use of antiserum directed against the CCK-2 receptor. Hyper-gastrinaemia may promote proliferation of human colonic adenomas that express CCK-2 receptor isoforms.


Assuntos
Adenocarcinoma/patologia , Adenoma/patologia , Neoplasias do Colo/patologia , Gastrinas/fisiologia , Proteínas de Neoplasias/fisiologia , Receptores da Colecistocinina/fisiologia , Adenocarcinoma/genética , Adenocarcinoma/metabolismo , Adenoma/genética , Adenoma/metabolismo , Animais , Neoplasias do Colo/genética , Neoplasias do Colo/metabolismo , Sistemas Computacionais , Inibidores Enzimáticos/farmacologia , Feminino , Fibroblastos/metabolismo , Mucosa Gástrica/efeitos dos fármacos , Mucosa Gástrica/metabolismo , Gastrinas/sangue , Gastrinas/metabolismo , Regulação Neoplásica da Expressão Gênica , Humanos , Íntrons/genética , Masculino , Camundongos , Camundongos SCID , Proteínas de Neoplasias/biossíntese , Proteínas de Neoplasias/genética , Transplante de Neoplasias , Omeprazol/farmacologia , Células Parietais Gástricas/metabolismo , Reação em Cadeia da Polimerase , Isoformas de Proteínas/biossíntese , Isoformas de Proteínas/genética , Isoformas de Proteínas/fisiologia , Processamento de Proteína Pós-Traducional , Inibidores da Bomba de Prótons , RNA Mensageiro/biossíntese , Receptor de Colecistocinina B , Receptores da Colecistocinina/biossíntese , Receptores da Colecistocinina/genética , Taxa Secretória/efeitos dos fármacos , Células Tumorais Cultivadas/metabolismo , Células Tumorais Cultivadas/patologia , Células Tumorais Cultivadas/transplante
15.
Br J Cancer ; 86(6): 963-70, 2002 Mar 18.
Artigo em Inglês | MEDLINE | ID: mdl-11953830

RESUMO

Magnetic resonance spectroscopy is increasingly used as a non-invasive method to investigate apoptosis. Apoptosis was induced in Jurkat T-cells by Fas mAb. (1)H magnetic resonance spectra of live cells showed an increase in methylene signal as well as methylene/methyl ratio of fatty acid side chains at 5 and 24 h following induction of apoptosis. To explain this observation, (1)H magnetic resonance spectra of cell extracts were investigated. These demonstrated a 70.0+/-7.0%, 114.0+/-8.0% and 90.0+/-5.0% increase in the concentration of triacylglycerols following 3, 5 and 7 h of Fas mAb treatment (P<0.05). Confocal microscopy images of cells stained with the lipophilic dye Nile Red demonstrated the presence of lipid droplets in the cell cytoplasm. Quantification of the stained lipids by flow cytometry showed a good correlation with the magnetic resonance results (P > or =0.05 at 3, 5 and 7 h). (31)P magnetic resonance spectra showed a drop in phosphatidylcholine content of apoptosing cells, indicating that alteration in phosphatidylcholine metabolism could be the source of triacylglycerol accumulation during apoptosis. In summary, apoptosis is associated with an early accumulation of mobile triacylglycerols mostly in the form of cytoplasmic lipid droplets. This is reflected in an increase in the methylene/methyl ratio which could be detected by magnetic resonance spectroscopy.


Assuntos
Apoptose , Triglicerídeos/metabolismo , Citometria de Fluxo , Humanos , Células Jurkat , Espectroscopia de Ressonância Magnética , Receptor fas/fisiologia
16.
Clin Cancer Res ; 7(11): 3544-50, 2001 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-11705875

RESUMO

Antitumor and pharmacodynamic studies were performed in MCF-7 human breast cancer cells and companion xenografts with the farnesyl protein transferase inhibitor, R115777, presently undergoing Phase II clinical trials, including in breast cancer. R115777 inhibited growth of MCF-7 cells in vitro with an IC(50) of 0.31 +/- 0.25 microM. Exposure of MCF-7 cells to increasing concentrations of R115777 for 24 h resulted in the inhibition of protein farnesylation, as indicated by the appearance of prelamin A at concentrations >1 microM. After continuous exposure to 2 microM R115777, prelamin A levels peaked at 2 h post drug exposure and remained high for up to 72 h. R115777 administered p.o. twice daily for 10 consecutive days to mice bearing established s.c. MCF-7 xenografts induced tumor inhibition at a dose of 25 mg/kg [percentage of treated versus control (% T/C) = 63% at day 21]. Greater inhibition was observed at doses of 50 mg/kg (% T/C at day 21 = 38%) or 100 mg/kg (% T/C at day 21 = 43%). The antitumor effect appeared to be mainly cytostatic with little evidence of tumor shrinkage to less than the starting volume. Tumor response correlated with an increase in the appearance of prelamin A, but no changes in the prenylation of lamin B, heat shock protein 40, or N-Ras were detectable. In addition, significant increases in apoptotic index and p21(WAF1/CIP1) expression were observed, concomitant with a decrease in proliferation as measured by Ki-67 staining. An increase in prelamin A was also observed in peripheral blood lymphocytes in a breast cancer patient who responded to R115777. These data show that R115777 possesses preclinical antitumor activity against human breast cancer and that the appearance of prelamin A may provide a sensitive and convenient pharmacodynamic marker of inhibition of prenylation and/or response.


Assuntos
Alquil e Aril Transferases/antagonistas & inibidores , Antineoplásicos/farmacologia , Neoplasias da Mama/tratamento farmacológico , Inibidores Enzimáticos/farmacologia , Quinolonas/farmacologia , Animais , Apoptose/efeitos dos fármacos , Neoplasias da Mama/metabolismo , Neoplasias da Mama/patologia , Divisão Celular/efeitos dos fármacos , Relação Dose-Resposta a Droga , Feminino , Células HT29 , Humanos , Imuno-Histoquímica , Antígeno Ki-67/análise , Lamina Tipo A , Camundongos , Camundongos Nus , Transplante de Neoplasias , Proteínas Nucleares/efeitos dos fármacos , Proteínas Nucleares/metabolismo , Precursores de Proteínas/efeitos dos fármacos , Precursores de Proteínas/metabolismo , Fatores de Tempo , Células Tumorais Cultivadas , Ensaios Antitumorais Modelo de Xenoenxerto
17.
Biochem Pharmacol ; 62(10): 1311-36, 2001 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-11709192

RESUMO

With the imminent completion of the Human Genome Project, biomedical research is being revolutionised by the ability to carry out investigations on a genome wide scale. This is particularly important in cancer, a disease that is caused by accumulating abnormalities in the sequence and expression of a number of critical genes. Gene expression microarray technology is gaining increasingly widespread use as a means to determine the expression of potentially all human genes at the level of messenger RNA. In this commentary, we review developments in gene expression microarray technology and illustrate the progress and potential of the methodology in cancer biology, pharmacology, and drug development. Important applications include: (a) development of a more global understanding of the gene expression abnormalities that contribute to malignant progression; (b) discovery of new diagnostic and prognostic indicators and biomarkers of therapeutic response; (c) identification and validation of new molecular targets for drug development; (d) provision of an improved understanding of the molecular mode of action during lead identification and optimisation, including structure-activity relationships for on-target versus off-target effects; (e) prediction of potential side-effects during preclinical development and toxicology studies; (f) confirmation of a molecular mode of action during hypothesis-testing clinical trials; (g) identification of genes involved in conferring drug sensitivity and resistance; and (h) prediction of patients most likely to benefit from the drug and use in general pharmacogenomic studies. As a result of further technological improvements and decreasing costs, the use of microarrays will become an essential and potentially routine tool for cancer and biomedical research.


Assuntos
Desenho de Fármacos , Neoplasias/genética , Animais , Previsões , Perfilação da Expressão Gênica , Humanos , Análise de Sequência com Séries de Oligonucleotídeos , Farmacologia/tendências , RNA Mensageiro/biossíntese
19.
Cancer Res ; 61(10): 4003-9, 2001 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-11358818

RESUMO

17-Allylamino-17-demethoxygeldanamycin (17AAG) is a first-in-class heat shock protein 90 (Hsp90) molecular chaperone inhibitor to enter clinical trials. The downstream molecular and cellular consequences of Hsp90 inhibition are not well defined. 17AAG has shown activity against human colon cancer in cell culture and xenograft models. In this study, we demonstrated that in addition to depleting c-Raf-1 and inhibiting ERK-1/2 phosphorylation in human colon adenocarcinoma cells, 17AAG also depleted N-ras, Ki-ras, and c-Akt and inhibited phosphorylation of c-AKT: A consequence of these events was the induction of cell line-dependent cytostasis and apoptosis, although the latter did not result from dephosphorylation of proapoptotic BAD: One cell line, KM12, did not exhibit apoptosis and in contrast to the other cell lines overexpressed Bag-1, but did not express BAX: Taken together with other determinants of 17AAG sensitivity, these results should contribute to a more complete understanding of the molecular pharmacology of 17AAG, which in turn should aid the future rational clinical development and use of the drug in colon and other tumor types.


Assuntos
Antibióticos Antineoplásicos/farmacologia , Apoptose/efeitos dos fármacos , Proteínas de Choque Térmico HSP90/antagonistas & inibidores , Proteínas Serina-Treonina Quinases , Rifabutina/farmacologia , Transdução de Sinais/efeitos dos fármacos , Adenocarcinoma/tratamento farmacológico , Adenocarcinoma/metabolismo , Adenocarcinoma/patologia , Apoptose/fisiologia , Benzoquinonas , Divisão Celular/efeitos dos fármacos , Neoplasias do Colo/tratamento farmacológico , Neoplasias do Colo/metabolismo , Neoplasias do Colo/patologia , Humanos , Lactamas Macrocíclicas , Proteína Quinase 1 Ativada por Mitógeno/antagonistas & inibidores , Proteína Quinase 1 Ativada por Mitógeno/metabolismo , Proteína Quinase 3 Ativada por Mitógeno , Proteínas Quinases Ativadas por Mitógeno/antagonistas & inibidores , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Fosforilação/efeitos dos fármacos , Proteínas Proto-Oncogênicas/metabolismo , Proteínas Proto-Oncogênicas c-akt , Proteínas Proto-Oncogênicas c-raf/metabolismo , Rifabutina/análogos & derivados , Transdução de Sinais/fisiologia , Células Tumorais Cultivadas , Proteínas ras/metabolismo
20.
Br J Surg ; 88(4): 564-8, 2001 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-11298626

RESUMO

BACKGROUND: A stepwise progression through premalignant stages has been identified for the intestinal type of gastric carcinoma. As gastrin has been identified as a growth factor for the intestinal type of gastric adenocarcinoma, the aim of this study was to investigate whether gastrin is expressed in premalignant gastric conditions. METHODS: Ninety archival samples of atrophic gastritis, intestinal metaplasia, mild gastric epithelial dysplasia, moderate gastric epithelial dysplasia, severe gastric epithelial dysplasia and intestinal-type gastric adenocarcinoma were obtained. Immunocytochemistry was performed using antibodies directed against gastrin and its post-translational precursors, and the gastrin/cholecystokinin B receptor. Positive staining was identified using the avidin--biotin immunoperoxidase method and quantified using an image analysis system. RESULTS: Gastrin and its receptor were shown to be expressed in specimens of atrophic gastritis, intestinal metaplasia, epithelial dysplasia and the intestinal type of gastric carcinoma. CONCLUSION: Gastrin seems to be an important growth factor in gastric carcinogenesis.


Assuntos
Adenocarcinoma/metabolismo , Biomarcadores Tumorais/metabolismo , Gastrinas/metabolismo , Neoplasias Gástricas/metabolismo , Adenocarcinoma/etiologia , Gastrinas/fisiologia , Humanos , Imuno-Histoquímica , Precursores de Proteínas/metabolismo , Antro Pilórico/metabolismo , Receptor de Colecistocinina B , Receptores da Colecistocinina/metabolismo , Neoplasias Gástricas/etiologia
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