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1.
Foods ; 11(2)2022 Jan 14.
Artigo em Inglês | MEDLINE | ID: mdl-35053952

RESUMO

Brown rice is nutritionally superior to white rice, yet oil rancidity can be problematic during processing and storage regarding sensory attributes. Germinating brown rice is known to generally increase some health-promoting compounds. In response to increasing the consumption of plant-based beverages, we sprouted unstabilized brown rice, using green technologies and saccharification enzymes for value-added beverages. 'Rondo' paddy rice was dehulled, sorted and germinated, and beverages were produced and compared against non-germinated brown and white brewers rice beverages. The preliminary germinated brown rice beverage contained significantly higher concentrations of total lipids, diacylglycerols, triacylglycerols, free sterols, phytosterol esters and oryzanols than both non-germinated brown and white rice beverages. White rice beverages had significantly higher free fatty acids. Significant lipid losses occurred during sieving, yet novel germinated brown rice beverages contained appreciable levels of valuable health-beneficial lipids, which appeared to form natural emulsions. Further pilot plant investigations should be scaled-up for pasteurization and adjusted through emulsification to ameliorate sieving losses.

2.
PLoS One ; 16(10): e0244332, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34610014

RESUMO

BACKGROUND: Colorectal cancer (CRC) is one of the leading causes of cancer-related death. Early detection is critical to reduce CRC morbidity and mortality. In order to meet this need, we developed a molecular clamping assay called the ColoScape TM assay for early colorectal cancer diagnostics. METHODS: Nineteen mutations in four genes (APC, KRAS, BRAF and CTNNB1) associated with early events in CRC pathogenesis are targeted in the ColoScapeTM assay. Xenonucleic Acid (XNA)-mediated qPCR clamping technology was applied to minimize the wild-type background amplification in order to improve assay sensitivity of CRC mutation detection. The assay analytical performance was verified and validated, cfDNA and FFPE CRC patient samples were evaluated, and an ROC curve was applied to evaluate its performance. RESULTS: The data showed that the assay analytical sensitivity was 0.5% Variant Allele Frequency, corresponding to ~7-8 copies of mutant DNA with 5 ng total DNA input per test. This assay is highly reproducible with intra-assay CV of <3% and inter-assay CV of <5%. We have investigated 380 clinical samples including plasma cfDNA and FFPE samples from patients with precancerous and different stages of CRC. The preliminary assay clinical specificity and sensitivity for CRC cfDNA were: 100% (95% CI, 80.3-97.5%) and 92.2% (95% CI, 94.7-100%), respectively, with AUC of 0.96; 96% specificity (95% CI, 77.6-99.7%) and 92% sensitivity (95% CI, 86.1-95.6%) with AUC of 0.94 for CRC FFPE; 95% specificity (95% CI, 82.5%-99.1%) and 62.5% sensitivity (95% CI, 35.8%-83.7%) with AUC of 0.79 for precancerous lesions cfDNA. CONCLUSIONS: The XNA-mediated molecular clamping assay is a rapid, precise, and sensitive assay for the detection of precancerous lesions cfDNA and CRC cfDNA or FFPE samples.


Assuntos
Neoplasias Colorretais/diagnóstico , Detecção Precoce de Câncer/métodos , Sequência de Bases , Linhagem Celular Tumoral , Ácidos Nucleicos Livres/genética , DNA Tumoral Circulante/genética , Neoplasias Colorretais/genética , DNA de Neoplasias/genética , Células HCT116 , Humanos , Mutação/genética , Reação em Cadeia da Polimerase em Tempo Real
3.
Chem Sci ; 10(9): 2592-2597, 2019 Mar 07.
Artigo em Inglês | MEDLINE | ID: mdl-30996974

RESUMO

We introduce the concept of surface radio-mineralisation (SRM) to describe the chelate-free radiolabelling of iron-oxide and ferrite nanoparticles. We demonstrate the effectiveness of SRM with both 111In and 89Zr for bare, polymer-matrix multicore, and surface-functionalised magnetite/maghemite nanoparticles; and for bare Y3Fe5O12 nanoparticles. By analogy with geological mineralisation (the hydrothermal deposition of metals as minerals in ore bodies or lodes) we demonstrate that the heat-induced and aqueous SRM process deposits radiometal-oxides onto the nanoparticle or core surfaces, passing through the matrix or coating if present, without changing the size, structure, or magnetic properties of the nanoparticle or core. We show in a mouse model followed over 7 days that the SRM is sufficient to allow quantitative, non-invasive, prolonged, whole-body localisation of injected nanoparticles with nuclear imaging.

4.
ACS Appl Electron Mater ; 1(8): 1408-1417, 2019 Aug 27.
Artigo em Inglês | MEDLINE | ID: mdl-32064464

RESUMO

Low-cost, high-efficiency, and high quality Cl-doped ZnO (ZnO:Cl) thin films that can simultaneously function as transparent conducting oxides (TCOs) and photocatalysts are described. The films have been fabricated by a facile and inexpensive solution-source aerosol-assisted chemical vapor deposition technique using NH4Cl as an effective, cheap, and abundant source of Cl. Successful ClO substitutional doping in the ZnO films was evident from powder X-ray diffraction, X-ray photoelectron spectroscopy, and time-of-flight secondary ion mass spectrometry results, while scanning electron microscopy reveals the impact of Cl doping on the ZnO thin film morphology. All ZnO:Cl films deposited were transparent and uncolored; optical transmittance in the visible region (400-700 nm) exceeded 80% for depositions using 5-20 mol % Cl. Optimal electrical properties were achieved when using 5 mol % Cl with a minimum measured resistivity of (2.72 ± 0.04) × 10-3 Ω·cm, in which the charge carrier concentration and mobility were measured at (8.58 ± 0.16) × 1019 cm-3 and 26.7 ± 0.1 cm2 V-1 s-1 respectively, corresponding to a sheet resistance (R sh) of 41.9 Ω□-1 at a thickness of 650 nm. In addition to transparent conducting properties, photocatalytic behavior of stearic acid degradation in the ZnO:Cl films was also observed with an optimal Cl concentration of 7 mol % Cl, with the highest formal quantum efficiency (ξ) measured at (1.63 ± 0.03) × 10-4 molecule/photon, while retaining a visible transparency of 80% and resistivity ρ = (9.23 ± 0.13) × 10-3 Ω·cm. The dual functionality of ZnO:Cl as both a transparent conductor and an efficient photocatalyst is a unique combination of properties making this a particularly unusual material.

5.
Chem Sci ; 9(41): 7968-7980, 2018 Nov 07.
Artigo em Inglês | MEDLINE | ID: mdl-30542551

RESUMO

Phosphorus doped tin(iv) oxide (P:SnO2) films have been synthesised by an aerosol assisted chemical vapour deposition route. Triethyl phosphate was used as the phosphorus dopant source. The phosphorus concentration in solution was found to be key to electrical properties, with concentrations between 0.25-0.5 mol% phosphorus giving the lowest resistivities of the deposited films. The conductivity of the films synthesised improved on doping SnO2 with phosphorus, with resistivity values of 7.27 × 10-4 Ω cm and sheet resistance values of 18.2 Ω â–¡-1 achieved for the most conductive films. Phosphorus doping up to 1.0 mol% was shown to improve visible light transmission of the deposited films. The phosphorus doping also had a significant effect on film morphology, with varying microstructures achieved. The films were characterised by X-ray diffraction, scanning electron microscopy, UV/vis spectroscopy, Hall effect measurements and X-ray photoelectron spectroscopy. The data generated was used to build computational models of phosphorus as a dopant for SnO2, showing that the phosphorus acts as a shallow one-electron n-type donor allowing for good conductivities. Phosphorus does not suffer from self-compensation issues associated with other dopants, such as fluorine.

6.
J Clin Pathol ; 71(12): 1123-1126, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30315134

RESUMO

Circulating cell free tumour derived nucleic acids are becoming recognised as clinically significant and extremely useful biomarkers for detection of cancer and for monitoring the progression of targeted drug therapy and immunotherapy. Screening programmes for colorectal cancer in Europe use the Fetal Immunochemical Test (FIT) test as a primary screener. FIT+ patients are referred to immediate colonoscopy and the positive predictive value (PPV) is usually 25%. In this article, we report a study employing the ColoScape assay panel to detect mutations in the APC, KRAS, BRAF and CTNNB1 genes, in order to collect preliminary performance indicators and plan a future, larger population study. The assay was evaluated on 52 prospectively collected whole-blood samples obtained from FIT+ patients enrolled in the CRC screening programme of ASL NAPOLI 3 SUD, using colonoscopy as confirmation. The assay's sensitivity for advanced adenomas was 53.8% and the specificity was 92.3%. The PPV was 70.0% and negative predicitive value (NPV) was 85.7%. Workflow optimisation is essential to maximise sensitivity. Of note, four of the six positive cases missed by ColoScape had a less than suboptimal DNA input (data not shown). Had they been ruled out as inadequate, sensitivity would have increased from 53.8% to 69%. However, as stated previously, this is not a clinical trial, but rather an initial, preliminary technical evaluation. In conclusion this study shows that ColoScape is a promising tool and further studies are warranted in order to validate its use for the triage of FIT+ patients.


Assuntos
Neoplasias Colorretais/diagnóstico , Colonoscopia , Neoplasias Colorretais/genética , Análise Mutacional de DNA , Humanos , Imunoquímica , Limite de Detecção , Biópsia Líquida , Reação em Cadeia da Polimerase Multiplex , Projetos Piloto , Sensibilidade e Especificidade , Triagem
7.
ACS Omega ; 3(4): 4342-4351, 2018 Apr 30.
Artigo em Inglês | MEDLINE | ID: mdl-29732454

RESUMO

We present the synthesis of nylon-12 scaffolds by 3D printing and demonstrate their versatility as matrices for cell growth, differentiation, and biomineral formation. We demonstrate that the porous nature of the printed parts makes them ideal for the direct incorporation of preformed nanomaterials or material precursors, leading to nanocomposites with very different properties and environments for cell growth. Additives such as those derived from sources such as tetraethyl orthosilicate applied at a low temperature promote successful cell growth, due partly to the high surface area of the porous matrix. The incorporation of presynthesized iron oxide nanoparticles led to a material that showed rapid heating in response to an applied ac magnetic field, an excellent property for use in gene expression and, with further improvement, chemical-free sterilization. These methods also avoid changing polymer feedstocks and contaminating or even damaging commonly used selective laser sintering printers. The chemically treated 3D printed matrices presented herein have great potential for use in addressing current issues surrounding bone grafting, implants, and skeletal repair, and a wide variety of possible incorporated material combinations could impact many other areas.

8.
Chemistry ; 23(62): 15543-15552, 2017 Nov 07.
Artigo em Inglês | MEDLINE | ID: mdl-28868621

RESUMO

Sustainability is an increasingly important topic in the design and manufacture of materials, with the need to reduce the environmental impact of producing materials being of paramount significance. A competing interest to this is the ability to produce functional materials in large volumes from a fast, on-line process, which can be integrated easily into existing industrial setups. Herein, we present aerosol-assisted chemical vapour deposition (AACVD) routes to advanced functional materials. We will show that by careful design of precursors and manipulation of deposition conditions, it is possible to achieve high sustainability whilst maintaining fast growth rates and large scale production of thin film functional materials.

9.
ACS Omega ; 2(3): 1040-1046, 2017 Mar 31.
Artigo em Inglês | MEDLINE | ID: mdl-31457486

RESUMO

Monoclinic vanadium(IV) oxide (VO2) has been widely studied for energy-efficient glazing applications because of its thermochromic properties, displaying a large change in transmission of near-IR wavelengths between the hot and cold states. The optimization of the reaction between VCl4 and ethyl acetate via atmospheric-pressure chemical vapor deposition (APCVD) was shown to produce thin films of monoclinic VO2 with excellent thermochromic properties (ΔT sol = 12%). The tailoring of the thermochromic and visible light transmission was shown to be possible by altering the density and morphology of the deposited films. The films were characterized by X-ray diffraction, atomic-force microscopy, scanning electron microscopy, ellipsometry, and UV-vis spectrometry. This article provides useful design rules for the synthesis of high-quality VO2 thin films by APCVD.

10.
Sci Rep ; 6: 34271, 2016 Sep 27.
Artigo em Inglês | MEDLINE | ID: mdl-27671546

RESUMO

Drug delivery to the gastrointestinal (GI) tract is highly challenging due to the harsh environments any drug- delivery vehicle must experience before it releases it's drug payload. Effective targeted drug delivery systems often rely on external stimuli to effect release, therefore knowing the exact location of the capsule and when to apply an external stimulus is paramount. We present a drug delivery system for the GI tract based on coating standard gelatin drug capsules with a model eicosane- superparamagnetic iron oxide nanoparticle composite coating, which is activated using magnetic hyperthermia as an on-demand release mechanism to heat and melt the coating. We also show that the capsules can be readily detected via rapid X-ray computed tomography (CT) and magnetic resonance imaging (MRI), vital for progressing such a system towards clinical applications. This also offers the opportunity to image the dispersion of the drug payload post release. These imaging techniques also influenced capsule content and design and the delivered dosage form. The ability to easily change design demonstrates the versatility of this system, a vital advantage for modern, patient-specific medicine.

11.
Chin J Cancer ; 35(1): 68, 2016 Jul 21.
Artigo em Inglês | MEDLINE | ID: mdl-27443349

RESUMO

Gastrointestinal stromal tumors (GISTs) have been recognized as a biologically distinctive type of tumor, different from smooth muscle and neural tumors of the gastrointestinal tract. The identification of genetic aberrations in proto-oncogenes that drive the growth of GISTs is critical for improving the efficacy of cancer therapy by matching targeted drugs to specific mutations. Research into the oncogenic mechanisms of GISTs has found that these tumors frequently contain activating gene mutations in either platelet-derived growth factor receptor A (PDGFRA) or a receptor tyrosine protein associated with a mast cell growth factor receptor encoded by the KIT gene. Mutant cancer subpopulations have the potential to disrupt durable patient responses to molecularly targeted therapy for GISTs, yet the prevalence and size of subpopulations remain largely unexplored. Detection of the cancer subpopulations that harbor low-frequency mutant alleles of target proto-oncogenes through the use of molecular genetic methods, such as polymerase chain reaction (PCR) target amplification technology, is hampered by the high abundance of wild-type alleles, which limit the sensitivity of detection of these minor mutant alleles. This is especially true in the case of mutant tumor DNA derived "driver" and "drug-resistant" alleles that are present in the circulating cell-free tumor DNA (cfDNA) in the peripheral blood circulation of GIST patients. So-called "liquid biopsy" allows for the dynamic monitoring of the patients' tumor status during treatment using minimally invasive sampling. New methodologies, such as a technology that employs a xenonucleic acid (XNA) clamping probe to block the PCR amplification of wild-type templates, have allowed improved molecular detection of these low-frequency alleles both in tissue biopsy samples and in cfDNA. These new methodologies could be widely applied for minimally invasive molecular testing in the therapeutic management of GISTs.


Assuntos
DNA de Neoplasias/genética , Neoplasias Gastrointestinais/diagnóstico , Neoplasias Gastrointestinais/genética , Tumores do Estroma Gastrointestinal/diagnóstico , Tumores do Estroma Gastrointestinal/genética , Análise Mutacional de DNA/métodos , Neoplasias Gastrointestinais/terapia , Tumores do Estroma Gastrointestinal/terapia , Humanos , Terapia de Alvo Molecular/métodos , Mutação , Reação em Cadeia da Polimerase/métodos , Inibidores de Proteínas Quinases/farmacologia
12.
Neoplasia ; 18(4): 253-63, 2016 04.
Artigo em Inglês | MEDLINE | ID: mdl-27108388

RESUMO

Mutant cancer subpopulations have the potential to derail durable patient responses to molecularly targeted cancer therapeutics, yet the prevalence and size of such subpopulations are largely unexplored. We employed the sensitive and quantitative Allele-specific Competitive Blocker PCR approach to characterize mutant cancer subpopulations in ductal carcinomas (DCs), examining five specific hotspot point mutations (PIK3CA H1047R, KRAS G12D, KRAS G12V, HRAS G12D, and BRAF V600E). As an approach to aid interpretation of the DC results, the mutations were also quantified in normal breast tissue. Overall, the mutations were prevalent in normal breast and DCs, with 9/9 DCs having measureable levels of at least three of the five mutations. HRAS G12D was significantly increased in DCs as compared to normal breast. The most frequent point mutation reported in DC by DNA sequencing, PIK3CA H1047R, was detected in all normal breast tissue and DC samples and was present at remarkably high levels (mutant fractions of 1.1 × 10(-3) to 4.6 × 10(-2)) in 4/10 normal breast samples. In normal breast tissue samples, PIK3CA mutation levels were positively correlated with age. However, the PIK3CA H1047R mutant fraction distributions for normal breast tissues and DCs were similar. The results suggest PIK3CA H1047R mutant cells have a selective advantage in breast, contribute to breast cancer susceptibility, and drive tumor progression during breast carcinogenesis, even when present as only a subpopulation of tumor cells.


Assuntos
Neoplasias da Mama/genética , Carcinoma Ductal de Mama/genética , Fosfatidilinositol 3-Quinases/genética , Proteínas Proto-Oncogênicas B-raf/genética , Proteínas ras/genética , Adulto , Idoso , Idoso de 80 Anos ou mais , Alelos , Neoplasias da Mama/patologia , Carcinoma Ductal de Mama/patologia , Estudos de Casos e Controles , Transformação Celular Neoplásica/genética , Classe I de Fosfatidilinositol 3-Quinases , Análise Mutacional de DNA , Feminino , Predisposição Genética para Doença , Humanos , Pessoa de Meia-Idade , Taxa de Mutação , Adulto Jovem
13.
Mol Endocrinol ; 29(2): 200-12, 2015 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-25545407

RESUMO

Hypogonadatropic hypogonadism (HH) can be acquired through energy restriction or may be inherited as congenital hypogonadotropic hypogonadism and its anosmia-associated form, Kallmann's syndrome. Congenital hypogonadotropic hypogonadism is associated with mutations in a group of genes that impact fibroblast growth factor 8 (FGF8) function. The Sirt1 gene encodes a nicotinamide adenine dinucleotide-dependent histone deacetylase that links intracellular metabolic stress to gene expression. Herein Sirt1(-/-) mice are shown to have HH due to failed GnRH neuronal migration. Sirtuin-1 (Sirt1) catalytic function induces GnRH neuronal migration via binding and deacetylating cortactin. Sirt1 colocalized with cortactin in GnRH neurons in vitro. Sirt1 colocalization with cortactin was regulated in an FGF8/fibroblast growth factor receptor-1 dependent manner. The profound effect of Sirt1 on the hormonal status of Sirt1(-/-) mice, mediated via defective GnRH neuronal migration, links energy metabolism directly to the hypogonadal state. Sirt1-cortactin may serve as the distal transducer of neuronal migration mediated by the FGF8 synexpression group of genes that govern HH.


Assuntos
Movimento Celular , Hormônio Liberador de Gonadotropina/metabolismo , Hipogonadismo/patologia , Neurônios/patologia , Sirtuína 1/deficiência , Acetilação , Animais , Biocatálise , Cortactina/metabolismo , Fatores de Crescimento de Fibroblastos/metabolismo , Camundongos , Modelos Biológicos , Ligação Proteica , Transporte Proteico , Receptor Tipo 1 de Fator de Crescimento de Fibroblastos , Transdução de Sinais , Sirtuína 1/metabolismo , Frações Subcelulares/metabolismo
14.
Am J Pathol ; 185(1): 266-79, 2015 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-25529796

RESUMO

Prostatic intraepithelial neoplasia is a precursor to prostate cancer. Herein, deletion of the NAD(+)-dependent histone deacetylase Sirt1 induced histological features of prostatic intraepithelial neoplasia at 7 months of age; these features were associated with increased cell proliferation and enhanced mitophagy. In human prostate cancer, lower Sirt1 expression in the luminal epithelium was associated with poor prognosis. Genetic deletion of Sirt1 increased mitochondrial superoxide dismutase 2 (Sod2) acetylation of lysine residue 68, thereby enhancing reactive oxygen species (ROS) production and reducing SOD2 activity. The PARK2 gene, which has several features of a tumor suppressor, encodes an E3 ubiquitin ligase that participates in removal of damaged mitochondria via mitophagy. Increased ROS in Sirt1(-/-) cells enhanced the recruitment of Park2 to the mitochondria, inducing mitophagy. Sirt1 restoration inhibited PARK2 translocation and ROS production requiring the Sirt1 catalytic domain. Thus, the NAD(+)-dependent inhibition of SOD2 activity and ROS by SIRT1 provides a gatekeeper function to reduce PARK2-mediated mitophagy and aberrant cell survival.


Assuntos
Regulação Neoplásica da Expressão Gênica , Mitocôndrias/metabolismo , Mitofagia , Neoplasia Prostática Intraepitelial/metabolismo , Sirtuína 1/metabolismo , Ubiquitina-Proteína Ligases/metabolismo , Células 3T3 , Animais , Sobrevivência Celular , Genótipo , Histona Desacetilases/metabolismo , Humanos , Imuno-Histoquímica , Masculino , Camundongos , Camundongos Transgênicos , Microscopia de Fluorescência , Estresse Oxidativo , Neoplasias da Próstata/genética , Neoplasias da Próstata/metabolismo , Transporte Proteico , Espécies Reativas de Oxigênio/metabolismo , Superóxido Dismutase/metabolismo
15.
Oncotarget ; 5(17): 7303-15, 2014 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-25229978

RESUMO

In our prior publications we characterized a conserved acetylation motif (K(R)xxKK) of evolutionarily related nuclear receptors. Recent reports showed that peroxisome proliferator activated receptor gamma (PPARγ) deacetylation by SIRT1 is involved in delaying cellular senescence and maintaining the brown remodeling of white adipose tissue. However, it still remains unknown whether lysyl residues 154 and 155 (K154/155) of the conserved acetylation motif (RIHKK) in Pparγ1 are acetylated. Herein, we demonstrate that Pparγ1 is acetylated and regulated by both endogenous TSA-sensitive and NAD-dependent deacetylases. Acetylation of lysine 154 was identified by mass spectrometry (MS) while deacetylation of lysine 155 by SIRT1 was confirmed by in vitro deacetylation assay. An in vivo labeling assay revealed K154/K155 as bona fide acetylation sites. The conserved acetylation sites of Pparγ1 and the catalytic domain of SIRT1 are both required for the interaction between Pparγ1 and SIRT1. Sirt1 and Pparγ1 converge to govern lipid metabolism in vivo. Acetylation-defective mutants of Pparγ1 were associated with reduced lipid synthesis in ErbB2 overexpressing breast cancer cells. Together, these results suggest that the conserved lysyl residues K154/K155 of Pparγ1 are acetylated and play an important role in lipid synthesis in ErbB2-positive breast cancer cells.


Assuntos
Neoplasias da Mama/metabolismo , Senescência Celular/fisiologia , Metabolismo dos Lipídeos/fisiologia , PPAR gama/metabolismo , Acetilação , Motivos de Aminoácidos/fisiologia , Animais , Western Blotting , Linhagem Celular Tumoral , Sequência Conservada , Humanos , Imunoprecipitação , Espectrometria de Massas , Camundongos , Mutação , Análise de Sequência com Séries de Oligonucleotídeos , Estrutura Terciária de Proteína/fisiologia , Sirtuína 1/metabolismo , Transfecção
16.
Nat Mater ; 12(9): 798-801, 2013 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-23832124

RESUMO

The most widely used oxide for photocatalytic applications owing to its low cost and high activity is TiO2. The discovery of the photolysis of water on the surface of TiO2 in 1972 launched four decades of intensive research into the underlying chemical and physical processes involved. Despite much collected evidence, a thoroughly convincing explanation of why mixed-phase samples of anatase and rutile outperform the individual polymorphs has remained elusive. One long-standing controversy is the energetic alignment of the band edges of the rutile and anatase polymorphs of TiO2 (ref. ). We demonstrate, through a combination of state-of-the-art materials simulation techniques and X-ray photoemission experiments, that a type-II, staggered, band alignment of ~ 0.4 eV exists between anatase and rutile with anatase possessing the higher electron affinity, or work function. Our results help to explain the robust separation of photoexcited charge carriers between the two phases and highlight a route to improved photocatalysts.


Assuntos
Titânio/química , Catálise , Modelos Químicos , Espectroscopia Fotoeletrônica
17.
Cancer Res ; 71(3): 964-75, 2011 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-21189328

RESUMO

The Sirtuin family of proteins (SIRT) encode a group of evolutionarily conserved, NAD-dependent histone deacetylases, involved in many biological pathways. SIRT1, the human homologue of the yeast Silent Information Regulator 2 (Sir2) gene, deacetylates histones, p300, p53, and the androgen receptor. Autophagy is required for the degradation of damaged organelles and long-lived proteins, as well as for the development of glands such as the breast and prostate. Herein, homozygous deletion of the Sirt1 gene in mice resulted in prostatic intraepithelial neoplasia (PIN) associated with reduced autophagy. Genome-wide gene expression analysis of Sirt1(-/-) prostates demonstrated that endogenous Sirt1 repressed androgen responsive gene expression and induced autophagy in the prostate. Sirt1 induction of autophagy occurred at the level of autophagosome maturation and completion in cultured prostate cancer cells. These studies provide novel evidence for a checkpoint function of Sirt1 in the development of PIN and further highlight a role for SIRT1 as a tumor suppressor in the prostate.


Assuntos
Autofagia/genética , Neoplasia Prostática Intraepitelial/genética , Neoplasias da Próstata/genética , Sirtuína 1/genética , Animais , Processos de Crescimento Celular/genética , Linhagem Celular Tumoral , Masculino , Camundongos , Camundongos Transgênicos , Neoplasia Prostática Intraepitelial/metabolismo , Neoplasia Prostática Intraepitelial/patologia , Neoplasias da Próstata/metabolismo , Neoplasias da Próstata/patologia , RNA Mensageiro/genética , Receptores Androgênicos/metabolismo , Transdução de Sinais , Sirtuína 1/metabolismo
18.
Trends Endocrinol Metab ; 21(1): 41-9, 2010 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-19896866

RESUMO

The dachshund (dac) gene was initially described as a mutant phenotype in flies featuring extremely short legs relative to their body length. Functioning as a dominant suppressor of the ellipse mutation, a hypermorphic allele of the Epidermal Growth Factor Receptor (EGFR), the dac gene plays a key role in metazoan development, regulating ocular, limb, brain, and gonadal development. In the Drosophila eye, dac is a key component of the Retinal Determination Gene Network (RDGN) governing the normal initiation of the morphogenetic furrow and thereby eye development. Recent studies have demonstrated an important role for human Dachshund homologue (DACH1) in tumorigenesis, in particular, breast, prostate and ovarian cancer. The molecular mechanisms by which DACH1 regulates differentiation and tumorigenesis are discussed herein.


Assuntos
Diferenciação Celular , Proteínas de Drosophila/metabolismo , Proteínas do Olho/metabolismo , Neoplasias/metabolismo , Proteínas Nucleares/metabolismo , Fatores de Transcrição/metabolismo , Animais , Proteínas de Ligação a DNA , Drosophila/genética , Drosophila/crescimento & desenvolvimento , Drosophila/metabolismo , Proteínas de Drosophila/genética , Proteínas do Olho/genética , Feminino , Humanos , Masculino , Camundongos , Invasividade Neoplásica , Neoplasias/genética , Neoplasias/patologia , Proteínas Nucleares/genética , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , Retina/crescimento & desenvolvimento , Retina/metabolismo , Fatores de Transcrição/genética
19.
Mol Biol Cell ; 19(6): 2566-78, 2008 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-18367547

RESUMO

The PC12 pheochromocytoma cell line responds to nerve growth factor (NGF) by exiting from the cell cycle and differentiating to induce extending neurites. Cyclin D1 is an important regulator of G1/S phase cell cycle progression, and it is known to play a role in myocyte differentiation in cultured cells. Herein, NGF induced cyclin D1 promoter, mRNA, and protein expression via the p21(RAS) pathway. Antisense- or small interfering RNA to cyclin D1 abolished NGF-mediated neurite outgrowth, demonstrating the essential role of cyclin D1 in NGF-mediated differentiation. Expression vectors encoding mutants of the Ras/mitogen-activated protein kinase pathway, and chemical inhibitors, demonstrated NGF induction of cyclin D1 involved cooperative interactions of extracellular signal-regulated kinase, p38, and phosphatidylinositol 3-kinase pathways downstream of p21(RAS). NGF induced the cyclin D1 promoter via Sp1, nuclear factor-kappaB, and cAMP-response element/activated transcription factor sites. NGF induction via Sp1 involved the formation of a Sp1/p50/p107 complex. Cyclin D1 induction by NGF governs differentiation and neurite outgrowth in PC12 cells.


Assuntos
Ciclina D1/genética , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , NF-kappa B/metabolismo , Fator de Crescimento Neural/farmacologia , Proteínas Proto-Oncogênicas p21(ras)/metabolismo , Fator de Transcrição Sp1/metabolismo , Animais , Sequência de Bases , Ciclo Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Ciclina D1/metabolismo , Humanos , Camundongos , Subunidade p50 de NF-kappa B/metabolismo , Neuritos/efeitos dos fármacos , Neuritos/enzimologia , Células PC12 , Fosfatidilinositol 3-Quinases/metabolismo , Regiões Promotoras Genéticas/genética , Ligação Proteica/efeitos dos fármacos , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , RNA Interferente Pequeno/metabolismo , Ratos , Proteína p107 Retinoblastoma-Like/metabolismo , Transcrição Gênica/efeitos dos fármacos , Proteínas Quinases p38 Ativadas por Mitógeno
20.
Mol Endocrinol ; 22(3): 539-45, 2008 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-18165438

RESUMO

It has been known since the early 1970s that nuclear receptor complexes bind DNA in association with coregulatory proteins. Characterization of these nuclear receptor coregulators has revealed diverse enzymatic activities that temporally and spatially coordinate nuclear receptor activity within the context of local chromatin in response to diverse hormone signals. Chromatin-modifying proteins, which dictate the higher-order chromatin structure in which DNA is packaged, in turn orchestrate orderly recruitment of nuclear receptor complexes. Modifications of histones include acetylation, methylation, phosphorylation, ubiquitylation, sumoylation, ADP ribosylation, deimination, and proline isomerization. At this time, we understand how a subset of these modifications regulates nuclear receptor signaling. However, the effects, particularly of acetylation and demethylation, are profound. The finding that nuclear receptors are directly acetylated and that acetylation in turn directly regulates contact-independent growth has broad therapeutic implications. Studies over the past 7 yr have led to the understanding that nuclear receptor acetylation is a conserved function, regulating diverse nuclear receptor activity. Furthermore, we now know that acetylation of multiple and distinct substrates within nuclear receptor signaling pathways, form an acetylation signaling network from the cell surface to the nucleus. The finding that nicotinamide adenine dinucleotide (NAD)-dependent histone deacetylases, the sirtuins, are capable of deacetylating nuclear receptors provides a new level of complexity in the control of nuclear receptor activity in which local intracellular concentrations of NAD may regulate nuclear receptor physiology.


Assuntos
Receptores Citoplasmáticos e Nucleares/metabolismo , Sirtuínas/metabolismo , Acetilação , Histonas/metabolismo , Processamento de Proteína Pós-Traducional , Transdução de Sinais
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