| 1. |
- Aguilar, Helena, et al.
(författare)
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VAV3 mediates resistance to breast cancer endocrine therapy
- 2014
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Ingår i: Breast Cancer Research. - : BioMed Central. - 1465-5411 .- 1465-542X. ; 16:3, s. R53-
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Tidskriftsartikel (refereegranskat)abstract
- INTRODUCTION: Endocrine therapies targeting cell proliferation and survival mediated by estrogen receptor alpha (ERalpha) are among the most effective systemic treatments for ERalpha-positive breast cancer. However, most tumors initially responsive to these therapies acquire resistance through mechanisms that involve ERalpha transcriptional regulatory plasticity. Here, we identify VAV3 as a critical component in this process.METHODS: A cell-based chemical compound screen was carried out to identify therapeutic strategies against resistance to endocrine therapy. Binding to ERalpha was evaluated by molecular docking analyses, an agonist fluoligand assay, and short-hairpin (sh) RNA-mediated protein depletion. Microarray analyses were performed to identify altered gene expression. Western blot of signaling and proliferation markers and shRNA-mediated protein depletion in viability and clonogenic assays were performed to delineate the role of VAV3. Genetic variation in VAV3 was assessed for association with the response to tamoxifen. Immunohistochemical analyses of VAV3 were carried out to determine the association with therapy response and different tumor markers. An analysis of gene expression association with drug sensitivity was carried out to identify a potential therapeutic approach based on differential VAV3 expression.RESULTS: The compound YC-1 was found to comparatively reduce the viability of cell models of acquired resistance. This effect was probably not due to activation of its canonical target (soluble guanylyl cyclase) but instead a result of binding to ERalpha. VAV3 was selectively reduced upon exposure to YC-1 or ERalpha depletion and, accordingly, VAV3 depletion comparatively reduced the viability of cell models of acquired resistance. In the clinical scenario, germline variation in VAV3 was associated with response to tamoxifen in Japanese breast cancer patients (rs10494071 combined P value = 8.4 x 10-4). The allele association combined with gene expression analyses indicated that low VAV3 expression predicts better clinical outcome. Conversely, high nuclear VAV3 expression in tumor cells was associated with poorer endocrine therapy response. Based on VAV3 expression levels and the response to erlotinib in cancer cell lines, targeting EGFR signaling may be a promising therapeutic strategy.CONCLUSIONS: This study proposes VAV3 as a biomarker and rationale signaling target to prevent and/or overcome resistance to endocrine therapy in breast cancer.
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| 2. |
- Antonino-Daviu, José Alfonso, et al.
(författare)
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Multi-harmonic tracking for diagnosis of rotor asymmetries in wound rotor induction motors
- 2013
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Ingår i: IECON Proceedings (Industrial Electronics Conference). - Piscataway, NJ : Institute of Electrical and Electronics Engineers (IEEE). - 9781479902248 ; , s. 5555-5560
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Konferensbidrag (refereegranskat)abstract
- Most of the research work hitherto carried out in the induction motors fault diagnosis area has been focused on squirrel-cage motors in spite of the fact that wound-rotor motors are typically less robust, having a more delicate maintenance. Over recent years, wound-rotor machines have drawn an increasing attention in the fault diagnosis community due to the advent of wind power technologies for electricity generation and the widely spread use of its generator variant, the Doubly-Fed Induction Generators (DFIGs) in that specific context. Nonetheless, there is still a lack of reliable techniques suited and properly validated in wound-rotor industrial induction motors. This paper proposes an integral methodology to diagnose rotor asymmetries in wound-rotor motors with high reliability. It is based on a twofold approach; the Empirical Mode Decomposition (EMD) method is employed to track the low-frequency fault-related components, while the Wigner-Ville Distribution (WVD) is used for detecting the high-frequency failure harmonics during a startup. Experimental results with real wound-rotor motors demonstrate that the combination of both perspectives enables to correctly diagnose the failure with higher reliability than alternative techniques relying on a unique informational source
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| 3. |
- Bladh, Johan
(författare)
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Hydropower generator and power system interaction
- 2012
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- After decades of routine operation, the hydropower industry faces new challenges. Large-scale integration of other renewable sources of generation in the power system accentuates the role of hydropower as a regulating resource. At the same time, an extensive reinvestment programme has commenced where many old components and apparatus are being refurbished or replaced. Introduction of new technical solutions in existing power plants requires good systems knowledge and careful consideration. Important tools for research, development and analysis are suitable mathematical models, numerical simulation methods and laboratory equipment. This doctoral thesis is devoted to studies of the electromechanical interaction between hydropower units and the power system. The work encompasses development of mathematical models, empirical methods for system identification, as well as numerical and experimental studies of hydropower generator and power system interaction. Two generator modelling approaches are explored: one based on electromagnetic field theory and the finite element method, and one based on equivalent electric circuits. The finite element model is adapted for single-machine infinite-bus simulations by the addition of a network equivalent, a mechanical equation and a voltage regulator. Transient simulations using both finite element and equivalent circuit models indicate that the finite element model typically overestimates the synchronising and damping properties of the machine. Identification of model parameters is performed both numerically and experimentally. A complete set of equivalent circuit parameters is identified through finite element simulation of standard empirical test methods. Another machine model is identified experimentally through frequency response analysis. An extension to the well-known standstill frequency response (SSFR) test is explored, which involves measurement and analysis of damper winding quantities. The test is found to produce models that are suitable for transient power system analysis. Both experimental and numerical studies show that low resistance of the damper winding interpole connections are vital to achieve high attenuation of rotor angle oscillations. Hydropower generator and power system interaction is also studied experimentally during a full-scale startup test of the Nordic power system, where multiple synchronised data acquisition devices are used for measurement of both electrical and mechanical quantities. Observation of a subsynchronous power oscillation leads to an investigation of the torsional stability of hydropower units. In accordance with previous studies, hydropower units are found to be mechanically resilient to subsynchronous power oscillations. However, like any other generating unit, they are dependent on sufficient electrical and mechanical damping. Two experimentally obtained hydraulic damping coefficients for a large Francis turbine runner are presented in the thesis.
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| 4. |
- Caliz, Rafael, et al.
(författare)
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Gender-Specific Effects of Genetic Variants within Th1 and Th17 Cell-Mediated Immune Response Genes on the Risk of Developing Rheumatoid Arthritis
- 2013
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Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 8:8
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Tidskriftsartikel (refereegranskat)abstract
- The present study was conducted to explore whether single nucleotide polymorphisms (SNPs) in Th1 and Th17 cell-mediated immune response genes differentially influence the risk of rheumatoid arthritis (RA) in women and men. In phase one, 27 functional/tagging polymorphisms in C-type lectins and MCP-1/CCR2 axis were genotyped in 458 RA patients and 512 controls. Carriers of Dectin-2(rs4264222T) allele had an increased risk of RA (OR = 1.47, 95% CI 1.10-1.96) whereas patients harboring the DC-SIGN(rs4804803G), MCP-1(rs1024611G), MCP-1(rs13900T) and MCP-1(rs4586C) alleles had a decreased risk of developing the disease (OR = 0.66, 95% CI 0.49-0.88; OR = 0.66, 95% CI 0.50-0.89; OR = 0.73, 95% CI 0.55-0.97 and OR = 0.68, 95% CI 0.51-0.91). Interestingly, significant gender-specific differences were observed for Dectin-2(rs4264222) and Dectin-2(rs7134303): women carrying the Dectin-2(rs4264222T) and Dectin-2(rs7134303G) alleles had an increased risk of RA (OR = 1.93, 95% CI 1.34-2.79 and OR = 1.90, 95% CI 1.29-2.80). Also five other SNPs showed significant associations only with one gender: women carrying the MCP-1(rs1024611G), MCP-1(rs13900T) and MCP-1(rs4586C) alleles had a decreased risk of RA (OR = 0.61, 95% CI 0.43-0.87; OR = 0.67, 95% CI 0.47-0.95 and OR = 0.60, 95% CI 0.42-0.86). In men, carriers of the DC-SIGN(rs2287886A) allele had an increased risk of RA (OR = 1.70, 95% CI 1.03-2.78), whereas carriers of the DC-SIGN(rs4804803G) had a decreased risk of developing the disease (OR = 0.53, 95% CI 0.32-0.89). In phase 2, we genotyped these SNPs in 754 RA patients and 519 controls, leading to consistent gender-specific associations for Dectin-2(rs4264222), MCP-1(rs1024611), MCP-1(rs13900) and DC-SIGN(rs4804803) polymorphisms in the pooled sample (OR = 1.38, 95% CI 1.08-1.77; OR = 0.74, 95% CI 0.58-0.94; OR = 0.76, 95% CI 0.59-0.97 and OR = 0.56, 95% CI 0.34-0.93). SNP-SNP interaction analysis of significant SNPs also showed a significant two-locus interaction model in women that was not seen in men. This model consisted of Dectin-2(rs4264222) and Dectin-2(rs7134303) SNPs and suggested a synergistic effect between the variants. These findings suggest that Dectin-2, MCP-1 and DC-SIGN polymorphisms may, at least in part, account for gender-associated differences in susceptibility to RA.
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| 5. |
- Pérez, Moisés, et al.
(författare)
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The fungal metabolite galiellalactone interferes with the nuclear import of NF-κB and inhibits HIV-1 replication.
- 2014
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Ingår i: Chemico-Biological Interactions. - : Elsevier BV. - 1872-7786 .- 0009-2797. ; 214:Mar 11, s. 69-76
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Tidskriftsartikel (refereegranskat)abstract
- Galiellalactone (GL) is a metabolite produced by the fungus Galiella rufa that presents antitumor and immunomodulatory activities. GL interferes with the binding to DNA of signal transducer and activator of transcription (STAT)-3 and also inhibits other signal pathways such as NF-κB, but the mechanism of action in this pathway remains unknown. In this study we report that GL inhibits vesicular stomatitis virus-recombinant HIV-1 infection and the NF-κB-dependent transcriptional activity of the HIV-LTR promoter. We found that GL prevents the binding of NF-κB to DNA but neither affects the phosphorylation and degradation of NF-κB inhibitory protein, IκBα, nor the phosphorylation and acetylation of the NF-κB p65 subunit. However, GL prevents the association of p65 with the importin α3 impairing the nuclear translocation of this transcription factor. Using a biotinylated probe we found that GL binds to p65 but not to importin α3. Therefore, GL is a dual NF-κB/STAT3 inhibitor that could serve as a lead compound for the development of novel drugs against HIV-1, cancer and inflammatory diseases.
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| 6. |
- Rubio-Moscardo, Fanny, et al.
(författare)
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Rare Variants in Calcium Homeostasis Modulator 1 (CALHM1) Found in Early Onset Alzheimer's Disease Patients Alter Calcium Homeostasis
- 2013
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Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 8:9, s. e74203-
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Tidskriftsartikel (refereegranskat)abstract
- Calcium signaling in the brain is fundamental to the learning and memory process and there is evidence to suggest that its dysfunction is involved in the pathological pathways underlying Alzheimer's disease (AD). Recently, the calcium hypothesis of AD has received support with the identification of the non-selective Ca2+-permeable channel CALHM1. A genetic polymorphism (p. P86L) in CALHM1 reduces plasma membrane Ca2+ permeability and is associated with an earlier age-at-onset of AD. To investigate the role of CALHM1 variants in early-onset AD (EOAD), we sequenced all CALHM1 coding regions in three independent series comprising 284 EOAD patients and 326 controls. Two missense mutations in patients (p.G330D and p.R154H) and one (p.A213T) in a control individual were identified. Calcium imaging analyses revealed that while the mutation found in a control (p.A213T) behaved as wild-type CALHM1 (CALHM1-WT), a complete abolishment of the Ca2+ influx was associated with the mutations found in EOAD patients (p.G330D and p.R154H). Notably, the previously reported p. P86L mutation was associated with an intermediate Ca2+ influx between the CALHM1-WT and the p.G330D and p. R154H mutations. Since neither expression of wild-type nor mutant CALHM1 affected amyloid beta-peptide (A beta) production or A beta-mediated cellular toxicity, we conclude that rare genetic variants in CALHM1 lead to Ca2+ dysregulation and may contribute to the risk of EOAD through a mechanism independent from the classical A beta cascade.
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