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1.
Histol Histopathol ; 35(6): 569-578, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31592535

RESUMO

BACKGROUND: The aim of this study was to investigate the role of the upstream kinase TAK1 and the canonical NF-κB pathway colorectal in cancer (CRC). Immunohistochemistry was used to assess the expression of TAK1/pTAK1 and canonical NF-κB pathway members in a tissue microarray of 242 patients. The relationship between expression, the tumour microenvironment and cancer-specific survival were examined. RESULTS: All the investigated members of the pathway were expressed in CRC tissue. In addition, cytoplasmic pTAK1 was associated with the tumour microenvironment (P=0.045) and cancer-specific survival (CSS) (P=0.032). When cytoplasmic pTAK1 was stratified by BRAF status, cytoplasmic pTAK1 expression association with CSS was strengthened (P=0.014). Cytoplasmic IKKß was significantly associated with the inflammatory cell infiltrate (P=0.015) as graded by Klintrup Makinen grade, systemic inflammation as assessed by neutrophil-lymphocyte ratio (P=0.03) and CSS (P=0.046). On multivariate analysis cytoplasmic IKKß was independently associated with CSS (HR 1.75,95%CI 1.05-2.91, P=0.033). CONCLUSION: Cytoplasmic pTAK1 was significantly associated with CSS and this was enhanced in patients with tumours that expressed wild type BRAF. High expression of cytoplasmic IKKß was significantly associated with decreased CSS and with markers of the tumour microenvironment. These results support the hypothesis that NF-κB pathway members are poor prognostic markers in patients with CRC, but this requires to be validated in a large independent cohort.


Assuntos
Neoplasias Colorretais , NF-kappa B/metabolismo , Microambiente Tumoral , Adulto , Idoso , Biomarcadores Tumorais/metabolismo , Estudos de Coortes , Neoplasias do Colo/metabolismo , Neoplasias do Colo/patologia , Neoplasias Colorretais/metabolismo , Neoplasias Colorretais/patologia , Feminino , Humanos , Imuno-Histoquímica/métodos , Inflamação , MAP Quinase Quinase Quinases/metabolismo , Masculino , Pessoa de Meia-Idade , Prognóstico
2.
Int J Cancer ; 144(1): 150-159, 2019 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-29992570

RESUMO

It is increasingly appreciated that host factors within the tumor center and microenvironment play a key role in dictating colorectal cancer (CRC) outcomes. As a result, the metastatic process has now been defined as a result of epithelial-mesenchymal transition (EMT). Establishment of the role of EMT within the tumor center and its effect on the tumor microenvironment would be beneficial for prognosis and therapeutic intervention in CRC. The present study assessed five immunohistochemical EMT markers within the tumor center on a 185 Stage II/III CRC patient tissue microarray. In 185 patients with CRC, cytoplasmic snail (HR 1.94 95% confidence interval [CI] 1.15-3.29, p = 0.012) and a novel combined EMT score (HR 3.86 95% CI 2.17-6.86, p < 0.001) were associated with decreased cancer-specific survival. The combined EMT score was also associated with increased tumor budding (p = 0.046), and systemic inflammation (p = 0.007), as well as decreased memory T-cells within the stroma (p = 0.030) and at the invasive margin (p = 0.035). Furthermore, the combined EMT score was associated with cancer-specific survival independent of TNM-stage (HR 4.12 95% CI 2.30-7.39, p < 0.001). In conclusion, a novel combined EMT score stratifies patient's survival in Stage II/III CRC and associates with key factors of tumor metastasis. Therefore, the combined EMT score could be used to identify patients at risk of micrometastases and who may benefit from standard adjuvant therapy, potentially in combination with EMT blockade.


Assuntos
Biomarcadores Tumorais/biossíntese , Neoplasias Colorretais/metabolismo , Transição Epitelial-Mesenquimal , Microambiente Tumoral , Idoso , Caderinas/biossíntese , Proteínas de Transporte/biossíntese , Neoplasias Colorretais/patologia , Neoplasias Colorretais/terapia , Feminino , Humanos , Imuno-Histoquímica , Estimativa de Kaplan-Meier , Masculino , Proteínas dos Microfilamentos/biossíntese , Pessoa de Meia-Idade , Estadiamento de Neoplasias , Prognóstico , Fatores de Transcrição da Família Snail/biossíntese , Homeobox 1 de Ligação a E-box em Dedo de Zinco/biossíntese , beta Catenina/biossíntese
3.
J Natl Cancer Inst ; 110(6): 616-627, 2018 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-29917140

RESUMO

Background: Aromatase inhibitors improve disease-free survival compared with tamoxifen in postmenopausal women with hormone receptor-positive breast cancer. The Tamoxifen and Exemestane Adjuvant Multinational (TEAM) trial compared exemestane monotherapy with sequential therapy of tamoxifen followed by exemestane. The trial failed to show a statistically significant difference between treatment arms. A robust translational program was established to investigate predictive biomarkers. Methods: A tissue microarray was retrospectively constructed using a subset of patient tissues (n = 4631) from the TEAM trial (n = 9766). Immunohistochemistry was performed for biomarkers, classed into three groups: MAPK pathway, NF-kappa B pathway, and estrogen receptor (ER) phosphorylation. Expression was analyzed for association with relapse-free survival (RFS) at 2.5 and 10 years and treatment regimen using Kaplan-Meier curves and log-rank analysis. All statistical tests were two-sided. Results: In univariate analysis, ER167 (hazard ratio [HR] = 0.71, 95% confidence interval [CI] = 0.59 to 0.85, P < .001), IKKα (HR = 0.74, 95% CI = 0.60 to 0.92, P = .005), Raf-1338 (HR = 0.64, 95% CI = 0.52 to 0.80, P < .001), and p44/42 MAPK202/204 (HR = 0.77, 95% CI = 0.64 to 0.92, P = .004) were statistically significantly associated with improved RFS at 10 years in patients receiving sequential therapy. Associations were strengthened when IKKα, Raf-1338, and ER167 were combined into a cumulative prognostic score (HR = 0.64, 95% CI = 0.52 to 0.77, P < .001). Patients with an all negative IKKα, Raf-1338, and ER167 score favored exemestane monotherapy (odds ratio = 0.56, 95% CI = 0.35 to 0.90). In multivariable analysis, the IKKα, Raf-1338, and ER167 score (P = .001) was an independent prognostic factor for RFS at 10 years in patients receiving sequential therapy. Conclusions: The IKKα, Raf-1338, and ER167 score is an independent predictive biomarker for lower recurrence on sequential therapy. Negative expression may further offer predictive value for exemestane monotherapy.


Assuntos
Androstadienos/uso terapêutico , Antineoplásicos Hormonais/uso terapêutico , Biomarcadores Tumorais/análise , Neoplasias da Mama/diagnóstico , Neoplasias da Mama/tratamento farmacológico , Tamoxifeno/uso terapêutico , Adulto , Idoso , Idoso de 80 Anos ou mais , Biomarcadores Farmacológicos/análise , Biomarcadores Farmacológicos/sangue , Biomarcadores Tumorais/sangue , Neoplasias da Mama/sangue , Quimioterapia Adjuvante , Intervalo Livre de Doença , Feminino , Humanos , Imuno-Histoquímica , Pessoa de Meia-Idade , Pós-Menopausa/sangue , Prognóstico , Estudos Retrospectivos , Resultado do Tratamento
4.
Int J Mol Sci ; 19(2)2018 Jan 31.
Artigo em Inglês | MEDLINE | ID: mdl-29385073

RESUMO

N-glycosylation profoundly affects the biological stability and function of therapeutic proteins, which explains the recent interest in glycoengineering technologies as methods to develop biobetter therapeutics. In current manufacturing processes, N-glycosylation is host-specific and remains difficult to control in a production environment that changes with scale and production batches leading to glycosylation heterogeneity and inconsistency. On the other hand, in vitro chemoenzymatic glycan remodeling has been successful in producing homogeneous pre-defined protein glycoforms, but needs to be combined with a cost-effective and scalable production method. An efficient chemoenzymatic glycan remodeling technology using a plant expression system that combines in vivo deglycosylation with an in vitro chemoenzymatic glycosylation is described. Using the monoclonal antibody rituximab as a model therapeutic protein, a uniform Gal2GlcNAc2Man3GlcNAc2 (A2G2) glycoform without α-1,6-fucose, plant-specific α-1,3-fucose or ß-1,2-xylose residues was produced. When compared with the innovator product Rituxan®, the plant-made remodeled afucosylated antibody showed similar binding affinity to the CD20 antigen but significantly enhanced cell cytotoxicity in vitro. Using a scalable plant expression system and reducing the in vitro deglycosylation burden creates the potential to eliminate glycan heterogeneity and provide affordable customization of therapeutics' glycosylation for maximal and targeted biological activity. This feature can reduce cost and provide an affordable platform to manufacture biobetter antibodies.


Assuntos
Rituximab/química , Anticorpos Monoclonais/química , Anticorpos Monoclonais/metabolismo , Glicosilação , Proteínas Recombinantes , Rituximab/metabolismo , Nicotiana/genética
5.
Oncotarget ; 8(20): 33002-33013, 2017 May 16.
Artigo em Inglês | MEDLINE | ID: mdl-28423692

RESUMO

The aim of the present study was to examine the relationship between tumour NF-κB activation, tumour microenvironment including local inflammatory response (LIR) and cancer-specific survival in patients with operable ductal breast cancer.Immunohistochemistry (tissue microarray of 376 patients) and western blotting (MCF7 and MDA-MB-231 breast cancer cells) was performed to assess expression of key members of the canonical NF-κB pathway (inhibitory kappa B kinase (IKKß) and phosphorylated p65 Ser-536 (p-p65)). Following silencing of IKKß, cell viability and apoptosis was assessed in both MCF7 and MDA-MB-231 cell lines.P-p65 was associated with cancer-specific survival (CSS) (nuclear P=0.042 and total P=0.025). High total p-p65 was associated with increase grade tumour grade (P=0.010), ER positivity (P=0.023), molecular subtype (P=0.005), lower Klintrup-Makinen grade (P=0.013) and decreased CD138 count (P=0.032). On multivariate analysis, total p-p65 expression independently associated with poorer CSS (P=0.020). In vitro work demonstrated that the canonical NF-κB pathway was inducible by exposure to TNFα in ER-positive MCF7 cells and to a lesser extent in ER-negative MDA-MB-231 cells. Reduction of IKKß expression by siRNA transfection increased levels of apoptosis and reduced cell viability in both MCF7 (P=<0.001, P=<0.001, respectively) and MDA-MB-231 cells (P=>0.001, P=0.002, respectively). This is consistent with the hypothesis that canonical IKKß-NF-κB signalling drives tumour survival.These results suggest that activation of the canonical NF-κB pathway is an important determinant of poor outcome in patients with invasive ductal breast cancer.


Assuntos
Neoplasias da Mama/patologia , Carcinoma Ductal de Mama/patologia , Quinase I-kappa B/metabolismo , NF-kappa B/metabolismo , Fatores de Transcrição/metabolismo , Proteínas Supressoras de Tumor/metabolismo , Neoplasias da Mama/metabolismo , Carcinoma Ductal de Mama/metabolismo , Linhagem Celular Tumoral , Sobrevivência Celular , Feminino , Humanos , Células MCF-7 , Gradação de Tumores , Fosforilação , Transdução de Sinais , Análise de Sobrevida , Microambiente Tumoral
6.
Int J Cancer ; 140(7): 1633-1644, 2017 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-28006839

RESUMO

The aim of our study was to examine the relationship between tumour IKKα expression and breast cancer recurrence and survival. Immunohistochemistry was employed in a discovery and a validation tissue microarray to assess the association of tumour IKKα expression and clinico-pathological characteristics. After siRNA-mediated silencing of IKKα, cell viability and apoptosis were assessed in MCF7 and MDA-MB-231 breast cancer cells. In both the discovery and validation cohorts, associations observed between IKKα and clinical outcome measures were potentiated in oestrogen receptor (ER) positive Luminal A tumours. In the discovery cohort, cytoplasmic IKKα was associated with disease-free survival (p = 0.029) and recurrence-free survival on tamoxifen (p < 0.001) in Luminal A tumours. Nuclear IKKα and a combination of cytoplasmic and nuclear IKKα (total tumour cell IKKα) were associated with cancer-specific survival (p = 0.012 and p = 0.007, respectively) and recurrence-free survival on tamoxifen (p = 0.013 and p < 0.001, respectively) in Luminal A tumours. In the validation cohort, cytoplasmic IKKα was associated with cancer-specific survival (p = 0.023), disease-free survival (p = 0.002) and recurrence-free survival on tamoxifen (p = 0.009) in Luminal A tumours. Parallel experiment with breast cancer cells in vitro demonstrated the non-canonical NF-κB pathway was inducible by exposure to lymphotoxin in ER-positive MCF7 cells and not in ER-negative MDA-MB-231 cells. Reduction in IKKα expression by siRNA transfection increased levels of apoptosis and reduced cell viability in MCF7 but not in MDA-MB-231 cells. IKKα is an important determinant of poor outcome in patients with ER-positive invasive ductal breast cancer and thus may represent a potential therapeutic target.


Assuntos
Neoplasias da Mama/metabolismo , Receptor alfa de Estrogênio/metabolismo , Regulação Neoplásica da Expressão Gênica , Quinase I-kappa B/metabolismo , Recidiva Local de Neoplasia/metabolismo , Idoso , Linhagem Celular Tumoral , Núcleo Celular/metabolismo , Sobrevivência Celular , Citoplasma/metabolismo , Intervalo Livre de Doença , Feminino , Perfilação da Expressão Gênica , Inativação Gênica , Humanos , Imuno-Histoquímica , Ligantes , Células MCF-7 , Pessoa de Meia-Idade , Fenobarbital/química , Prognóstico , RNA Interferente Pequeno/metabolismo , Estudos Retrospectivos , Tamoxifeno/química , Resultado do Tratamento
7.
Oncotarget ; 7(43): 70601-70612, 2016 Oct 25.
Artigo em Inglês | MEDLINE | ID: mdl-27661110

RESUMO

In patients with colorectal cancer (CRC), local and systemic inflammatory responses have been extensively reported to associate with cancer survival. However, the specific signalling pathways responsible for inflammatory responses are not clear. The PTEN/Akt pathway is a plausible candidate as it may play a role in mediating inflammation via COX-2, and has been associated with cancer progression. This study therefore examined the relationship between tumour PTEN/Akt/COX-2 expression, inflammatory responses and survival in CRC patients using a tissue microarray.In 201 CRC patients, activation of tumour-specific PTEN/Akt significantly associated with poorer CSS (12.0yrs v 7.3yrs, P=0.032), poorer differentiation (P=0.032), venous invasion (P=0.008) and peritoneal involvement (P=0.004). Patients were stratified for peri-nuclear expression of COX-2 to examine associations with inflammatory responses. In patients with absent peri-nuclear COX-2 expression, activation of tumour-specific PTEN/Akt significantly associated with poorer CSS (11.9yrs v 5.4yrs, P=0.001), poorer differentiation (P=0.018), venous invasion (P=0.003) and peritoneal involvement (P=0.001). However, no associations were seen with either the local or systemic inflammatory responses.In CRC patients, tumour-specific PTEN/Akt pathway activation was significantly associated with poorer CSS, particularly when peri-nuclear COX-2 expression was absent. However, activation of the PTEN/Akt pathway appears not to be responsible for the regulation of inflammatory responses.


Assuntos
Neoplasias Colorretais/metabolismo , Ciclo-Oxigenase 2/biossíntese , PTEN Fosfo-Hidrolase/biossíntese , Proteínas Proto-Oncogênicas c-akt/biossíntese , Idoso , Neoplasias Colorretais/patologia , Progressão da Doença , Feminino , Humanos , Imuno-Histoquímica , Estimativa de Kaplan-Meier , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Transdução de Sinais , Síndrome de Resposta Inflamatória Sistêmica/metabolismo
8.
Plant Biotechnol J ; 13(8): 1180-90, 2015 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-26387511

RESUMO

Rapid, large-scale manufacture of medical countermeasures can be uniquely met by the plant-made-pharmaceutical platform technology. As a participant in the Defense Advanced Research Projects Agency (DARPA) Blue Angel project, the Caliber Biotherapeutics facility was designed, constructed, commissioned and released a therapeutic target (H1N1 influenza subunit vaccine) in <18 months from groundbreaking. As of 2015, this facility was one of the world's largest plant-based manufacturing facilities, with the capacity to process over 3500 kg of plant biomass per week in an automated multilevel growing environment using proprietary LED lighting. The facility can commission additional plant grow rooms that are already built to double this capacity. In addition to the commercial-scale manufacturing facility, a pilot production facility was designed based on the large-scale manufacturing specifications as a way to integrate product development and technology transfer. The primary research, development and manufacturing system employs vacuum-infiltrated Nicotiana benthamiana plants grown in a fully contained, hydroponic system for transient expression of recombinant proteins. This expression platform has been linked to a downstream process system, analytical characterization, and assessment of biological activity. This integrated approach has demonstrated rapid, high-quality production of therapeutic monoclonal antibody targets, including a panel of rituximab biosimilar/biobetter molecules and antiviral antibodies against influenza and dengue fever.


Assuntos
Terapia Biológica/economia , Preparações Farmacêuticas/economia , Preparações Farmacêuticas/metabolismo , Plantas/metabolismo , Anticorpos Monoclonais/biossíntese , Biotecnologia , Humanos , Plantas/genética , Plantas Geneticamente Modificadas
9.
Am J Cancer Res ; 3(5): 446-64, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-24224123

RESUMO

Raf Kinase inhibitory protein (RKIP) is a well-established metastasis suppressor that is frequently downregulated in aggressive cancers. The impact of RKIP and its phosphorylated form on disease-free survival (DFS) and other clinicopathological parameters in breast cancer is yet to be discovered. To this end, we examined RKIP expression in 3 independent breast cancer cohorts. At the Protein level, loss or reduced total RKIP expression was associated with large-sized tumors characterized by high proliferative index, high-grade and diminished estrogen (ER) and progesterone receptor expression. Loss or diminution of RKIP expression was significantly associated with shorter DFS in all cohorts. Moreover, the complete loss of p-RKIP was an independent prognostic factor using multivariate analysis in operable invasive ductal breast cancer. We show for the first time that ER, partly, drives RKIP expression through MTA3-Snail axis. Consistent with this finding, we found that, at the mRNA level, RKIP expression varied significantly across the different molecular subtypes of breast cancer with the Luminal (ER+) subtype expressing high levels of RKIP and the more aggressive Claudin-low (ER-) subtype, which depicted the highest epithelial to mesenchymal transition (EMT) registered the lowest RKIP expression levels. In conclusion, loss of expression/diminution of RKIP or its phosphorylated form is associated with poor diseases-free survival in breast cancer. Determining the expression of RKIP and p-RKIP adds significant prognostic value to the management and subtyping of this disease.

10.
Int J Mol Sci ; 14(8): 16656-71, 2013 Aug 13.
Artigo em Inglês | MEDLINE | ID: mdl-23945560

RESUMO

We previously reported that AR phosphorylation at serine 213 was associated with poor outcome and may contribute to prostate cancer development and progression. This study investigates if specific AR phosphorylation sites have differing roles in the progression of hormone naïve prostate cancer (HNPC) to castrate resistant disease (CRPC). A panel of phosphospecific antibodies were employed to study AR phosphorylation in 84 matched HNPC and CRPC tumours. Immunohistochemistry measured Androgen receptor expression phosphorylated at serine residues 94 (pAR94), 308 (pAR308), 650(pAR650) and 791 (pAR791). No correlations with clinical parameters were observed for pAR94 or pAR650 in HNPC or CRPC tumours. In contrast to our previous observation with serine 213, high pAR308 is significantly associated with a longer time to disease specific death (p = 0.011) and high pAR791 expression significantly associated with a longer time to disease recurrence (p = 0.018) in HNPC tumours and longer time to death from disease recurrence (p = 0.040) in CRPC tumours. This observation in CRPC tumours was attenuated in high apoptotic tumours (p = 0.022) and low proliferating tumours (p = 0.004). These results demonstrate that understanding the differing roles of AR phosphorylation is necessary before this can be exploited as a target for castrate resistant prostate cancer.


Assuntos
Neoplasias de Próstata Resistentes à Castração/metabolismo , Neoplasias de Próstata Resistentes à Castração/mortalidade , Receptores Androgênicos/metabolismo , Proliferação de Células , Humanos , Imuno-Histoquímica , Masculino , Recidiva Local de Neoplasia/metabolismo , Recidiva Local de Neoplasia/mortalidade , Fosforilação , Sobrevida
11.
BMC Ecol ; 10: 19, 2010 Aug 27.
Artigo em Inglês | MEDLINE | ID: mdl-20799959

RESUMO

BACKGROUND: Hyperaccumulation, the rare capacity of certain plant species to accumulate toxic trace elements to levels several orders of magnitude higher than other species growing on the same site, is thought to be an elemental defense mechanism against herbivores and pathogens. Previous research has shown that selenium (Se) hyperaccumulation protects plants from a variety of herbivores and pathogens. Selenium hyperaccumulating plants sequester Se in discrete locations in the leaf periphery, making them potentially more susceptible to some herbivore feeding modes than others. In this study we investigate the protective function of Se in the Se hyperaccumulators Stanleya pinnata and Astragalus bisulcatus against two cell disrupting herbivores, the western flower thrips (Frankliniella occidentalis) and the two-spotted spider mite (Tetranychus urticae). RESULTS: Astragalus bisulcatus and S. pinnata with high Se concentrations (greater than 650 mg Se kg(-1)) were less subject to thrips herbivory than plants with low Se levels (less than 150 mg Se kg(-1)). Furthermore, in plants containing elevated Se levels, leaves with higher concentrations of Se suffered less herbivory than leaves with less Se. Spider mites also preferred to feed on low-Se A. bisulcatus and S. pinnata plants rather than high-Se plants. Spider mite populations on A. bisulcatus decreased after plants were given a higher concentration of Se. Interestingly, spider mites could colonize A. bisulcatus plants containing up to 200 mg Se kg(-1) dry weight, concentrations which are toxic to many other herbivores. Selenium distribution and speciation studies using micro-focused X-ray fluorescence (µXRF) mapping and Se K-edge X-ray absorption spectroscopy revealed that the spider mites accumulated primarily methylselenocysteine, the relatively non-toxic form of Se that is also the predominant form of Se in hyperaccumulators. CONCLUSIONS: This is the first reported study investigating the protective effect of hyperaccumulated Se against cell-disrupting herbivores. The finding that Se protected the two hyperaccumulator species from both cell disruptors lends further support to the elemental defense hypothesis and increases the number of herbivores and feeding modes against which Se has shown a protective effect. Because western flower thrips and two-spotted spider mites are widespread and economically important herbivores, the results from this study also have potential applications in agriculture or horticulture, and implications for the management of Se-rich crops.


Assuntos
Astrágalo/metabolismo , Brassicaceae/metabolismo , Insetos/fisiologia , Selênio/metabolismo , Tetranychidae/fisiologia , Animais , Cisteína/análogos & derivados , Cisteína/metabolismo , Cisteína/toxicidade , Preferências Alimentares , Compostos Organosselênicos/metabolismo , Compostos Organosselênicos/toxicidade , Selênio/toxicidade , Selenocisteína/análogos & derivados
12.
Cell Cycle ; 7(17): 2630-4, 2008 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-18728391

RESUMO

Circadian clocks and mitogen-activated protein kinase (MAPK) signaling pathways are fundamental features of eukaryotic cells. Both pathways provide mechanisms for cells to respond to environmental stimuli, and links between them are known. We recently reported that the circadian clock in Neurospora crassa regulates daily rhythms in accumulation of phosphorylated, and thus active, OS-2 MAPK, a relative of mammalian p38 MAPK, when cells are grown in constant conditions. In the absence of acute stress, rhythmically activated MAPK then signals to downstream effector molecules to regulate rhythmic expression of target genes of the pathway. Clock regulation of MAPK signaling pathways provides a mechanism to coordinately control major groups of genes such that they peak at the appropriate times of day to provide a growth and survival advantage to the organism by anticipating stresses. MAPK pathways are well known for their role in cell proliferation and tumor suppression. New evidence reveals that some mammalian clock components also function as tumor suppressors and rhythms in phospho-MAPK have been observed in higher eukaryotes. Thus, the role of the clock in regulation of the activity of MAPK pathways provides important clues into the function of the circadian clock as a tumor suppressor.


Assuntos
Relógios Biológicos/fisiologia , Ritmo Circadiano/fisiologia , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Neurospora crassa/enzimologia , Animais , Proteínas Quinases Ativadas por Mitógeno/metabolismo
13.
J Environ Qual ; 32(2): 432-40, 2003.
Artigo em Inglês | MEDLINE | ID: mdl-12708665

RESUMO

Transgenic Indian mustard [Brassica juncea (L.) Czern.] plants overproducing the enzymes gamma-glutamylcysteine synthetase (ECS) or glutathione synthetase (GS) were shown previously to have increased levels of the metal-binding thiol peptides phytochelatins and glutathione, and enhanced Cd tolerance and accumulation. Furthermore, transgenic Indian mustard plants overexpressing adenosine triphosphate sulfurylase (APS) were shown to have higher levels of glutathione and total thiols. These results were obtained with a solution culture. To better examine the phytoremediation potential of these transgenics, a greenhouse experiment was performed in which the transgenics were grown on metal-contaminated soil collected from a USEPA Superfund site near Leadville, Colorado. A grass mixture used for revegetation of the site was included for comparison. The ECS and GS transgenics accumulated significantly (P < 0.05) more metal in their shoot than wild-type (WT) Indian mustard, while the APS plants did not. Of the six metals tested, the ECS and GS transgenics accumulated 1.5-fold more Cd, and 1.5- to 2-fold more Zn, compared with wild-type Indian mustard. Furthermore, the ECS transgenics accumulated 2.4- to 3-fold more Cr, Cu, and Pb, relative to WT. The grass mixture accumulated significantly less metal than Indian mustard: approximately 2-fold less Cd, Cu, Mn, and Zn, and 5.7-fold less Pb than WT Indian mustard. All transgenics removed significantly more metal from the soil compared with WT Indian mustard or an unplanted control. While WT did not remove more metal than the unplanted control for any of the metals tested, all three types of transgenics significantly reduced the soil metal concentration, and removed between 6% (Zn) and 25% (Cd) of the soil metal. This study is the first to demonstrate enhanced phytoextraction potential of transgenic plants using polluted environmental soil. The results confirm the importance of metal-binding peptides for plant metal accumulation and show that results from hydroponic systems have value as an indicator for phytoremediation potential.


Assuntos
Metais Pesados/farmacocinética , Mostardeira/genética , Mostardeira/fisiologia , Plantas Geneticamente Modificadas , Poluentes do Solo/farmacocinética , Sulfato Adenililtransferase/farmacologia , Biodegradação Ambiental , Regulação da Expressão Gênica , Sulfato Adenililtransferase/genética
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