298 research outputs found

    Targeting a phospho-STAT3-miRNAs pathway improves vesicular hepatic steatosis in an in vitro and in vivo model

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    Non-alcoholic fatty liver disease (NAFLD) is a leading cause of chronic liver disease. Although genetic predisposition and epigenetic factors contribute to the development of NAFLD, our understanding of the molecular mechanism involved in the pathogenesis of the disease is still emerging. Here we investigated a possible role of a microRNAs-STAT3 pathway in the induction of hepatic steatosis. Differentiated HepaRG cells treated with the fatty acid sodium oleate (fatty dHepaRG) recapitulated features of liver vesicular steatosis and activated a cell-autonomous inflammatory response, inducing STAT3-Tyrosine-phosphorylation. With a genome-wide approach (Chromatin Immunoprecipitation Sequencing), many phospho-STAT3 binding sites were identified in fatty dHepaRG cells and several STAT3 and/or NAFLD-regulated microRNAs showed increased expression levels, including miR-21. Innovative CARS (Coherent Anti-Stokes Raman Scattering) microscopy revealed that chemical inhibition of STAT3 activity decreased lipid accumulation and deregulated STAT3-responsive microRNAs, including miR-21, in lipid overloaded dHepaRG cells. We were able to show in vivo that reducing phospho-STAT3-miR-21 levels in C57/BL6 mice liver, by long-term treatment with metformin, protected mice from aging-dependent hepatic vesicular steatosis. Our results identified a microRNAs-phosphoSTAT3 pathway involved in the development of hepatic steatosis, which may represent a molecular marker for both diagnosis and therapeutic targeting

    Wt-p53 action in human leukaemia cell lines corresponding to different stages of differentiation.

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    Recent studies support the potential application of the wt-p53 gene in cancer therapy. Expression of exogenous wt-p53 suppresses a variety of leukaemia phenotypes by acting on cell survival, proliferation and/or differentiation. As for tumour gene therapy, the final fate of the neoplastic cells is one of the most relevant points. We examined the effects of exogenous wt-p53 gene expression in several leukaemia cell lines to identify p53-responsive leukaemia. The temperature-sensitive p53Val135 mutant or the human wt-p53 cDNA was transduced in leukaemia cell lines representative of different acute leukaemia FAB subtypes, including M1 (KG1), M2 (HL-60), M3 (NB4), M5 (U937) and M6 (HEL 92.1.7), as well as blast crisis of chronic myelogenous leukaemia (BC-CML: K562, BV173) showing diverse differentiation features. By morphological, molecular and biochemical analyses, we have shown that exogenous wt-p53 gene expression induces apoptosis only in cells corresponding to M1, M2 and M3 of the FAB classification and in BC-CML showing morphological and cytochemical features of undifferentiated blast cells. In contrast, it promotes differentiation in the others. Interestingly, cell responsiveness was independent of the vector used and the status of the endogenous p53 gene

    Heralded Noiseless Amplification of a Photon Polarization Qubit

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    Non-deterministic noiseless amplification of a single mode can circumvent the unique challenges to amplifying a quantum signal, such as the no-cloning theorem, and the minimum noise cost for deterministic quantum state amplification. However, existing devices are not suitable for amplifying the fundamental optical quantum information carrier, a qubit coherently encoded across two optical modes. Here, we construct a coherent two-mode amplifier, to demonstrate the first heralded noiseless linear amplification of a qubit encoded in the polarization state of a single photon. In doing so, we increase the transmission fidelity of a realistic qubit channel by up to a factor of five. Qubit amplifiers promise to extend the range of secure quantum communication and other quantum information science and technology protocols.Comment: 6 pages, 3 figure

    Mutant p53 sustains serine-glycine synthesis and essential amino acids intake promoting breast cancer growth

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    : Reprogramming of amino acid metabolism, sustained by oncogenic signaling, is crucial for cancer cell survival under nutrient limitation. Here we discovered that missense mutant p53 oncoproteins stimulate de novo serine/glycine synthesis and essential amino acids intake, promoting breast cancer growth. Mechanistically, mutant p53, unlike the wild-type counterpart, induces the expression of serine-synthesis-pathway enzymes and L-type amino acid transporter 1 (LAT1)/CD98 heavy chain heterodimer. This effect is exacerbated by amino acid shortage, representing a mutant p53-dependent metabolic adaptive response. When cells suffer amino acids scarcity, mutant p53 protein is stabilized and induces metabolic alterations and an amino acid transcriptional program that sustain cancer cell proliferation. In patient-derived tumor organoids, pharmacological targeting of either serine-synthesis-pathway and LAT1-mediated transport synergizes with amino acid shortage in blunting mutant p53-dependent growth. These findings reveal vulnerabilities potentially exploitable for tackling breast tumors bearing missense TP53 mutations

    A Survey of Air-to-Ground Propagation Channel Modeling for Unmanned Aerial Vehicles

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    In recent years, there has been a dramatic increase in the use of unmanned aerial vehicles (UAVs), particularly for small UAVs, due to their affordable prices, ease of availability, and ease of operability. Existing and future applications of UAVs include remote surveillance and monitoring, relief operations, package delivery, and communication backhaul infrastructure. Additionally, UAVs are envisioned as an important component of 5G wireless technology and beyond. The unique application scenarios for UAVs necessitate accurate air-to-ground (AG) propagation channel models for designing and evaluating UAV communication links for control/non-payload as well as payload data transmissions. These AG propagation models have not been investigated in detail when compared to terrestrial propagation models. In this paper, a comprehensive survey is provided on available AG channel measurement campaigns, large and small scale fading channel models, their limitations, and future research directions for UAV communication scenarios

    Physicochemical and biological characterization of chitosan-microRNA nanocomplexes for gene delivery to MCF-7 breast cancer cells

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    Cancer gene therapy requires the design of non-viral vectors that carry genetic material and selectively deliver it with minimal toxicity. Non-viral vectors based on cationic natural polymers can form electrostatic complexes with negatively-charged polynucleotides such as microRNAs (miRNAs). Here we investigated the physicochemical/biophysical properties of chitosan–hsa-miRNA-145 (CS–miRNA) nanocomplexes and the biological responses of MCF-7 breast cancer cells cultured in vitro. Self-assembled CS–miRNA nanocomplexes were produced with a range of (+/−) charge ratios (from 0.6 to 8) using chitosans with various degrees of acetylation and molecular weight. The Z-average particle diameter of the complexes was <200 nm. The surface charge increased with increasing amount of chitosan. We observed that chitosan induces the base-stacking of miRNA in a concentration dependent manner. Surface plasmon resonance spectroscopy shows that complexes formed by low degree of acetylation chitosans are highly stable, regardless of the molecular weight. We found no evidence that these complexes were cytotoxic towards MCF-7 cells. Furthermore, CS–miRNA nanocomplexes with degree of acetylation 12% and 29% were biologically active, showing successful downregulation of target mRNA expression in MCF-7 cells. Our data, therefore, shows that CS–miRNA complexes offer a promising non-viral platform for breast cancer gene therapy

    Neuronal characteristics of small-cell lung cancer

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    Wide ranging experimental evidence suggests that human small-cell lung cancer (SCLC) has a number of molecular and subcellular characteristics normally associated with neurones. This review outlines and discusses these characteristics in the light of recent developments in the field. Emphasis is placed upon neuronal cell adhesion molecules, neurone-restrictive silencer factor, neurotransmitters/peptides and voltage-gated ion, especially Na+ channels. The hypothesis is put forward that acquisition of such characteristics and the membrane ‘excitability' that would follow can accelerate metastatic progression. The clinical potential of the neuronal characteristics of SCLC, in particular ion channel expression/activity, is discussed in relation to possible novel diagnostic and therapeutic modalities
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