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Search Results: 1 - 10 of 585 matches for " Cristiana Caliceti "
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Dietary Phenolic Acids Act as Effective Antioxidants in Membrane Models and in Cultured Cells, Exhibiting Proapoptotic Effects in Leukaemia Cells
Laura Zambonin,Cristiana Caliceti,Francesco Vieceli Dalla Sega,Diana Fiorentini,Silvana Hrelia,Laura Landi,Cecilia Prata
Oxidative Medicine and Cellular Longevity , 2012, DOI: 10.1155/2012/839298
Abstract: Caffeic, syringic, and protocatechuic acids are phenolic acids derived directly from food intake or come from the gut metabolism of polyphenols. In this study, the antioxidant activity of these compounds was at first evaluated in membrane models, where caffeic acid behaved as a very effective chain-breaking antioxidant, whereas syringic and protocatechuic acids were only retardants of lipid peroxidation. However, all three compounds acted as good scavengers of reactive species in cultured cells subjected to exogenous oxidative stress produced by low level of H2O2. Many tumour cells are characterised by increased ROS levels compared with their noncancerous counterparts. Therefore, we investigated whether phenolic acids, at low concentrations, comparable to those present in human plasma, were able to decrease basal reactive species. Results show that phenolic acids reduced ROS in a leukaemia cell line (HEL), whereas no effect was observed in normal cells, such as HUVEC. The compounds exhibited no toxicity to normal cells while they decreased proliferation in leukaemia cells, inducing apoptosis. In the debate on optimal ROS-manipulating strategies in cancer therapy, our work in leukaemia cells supports the antioxidant ROS-depleting approach.
Effect of Plasma Membrane Cholesterol Depletion on Glucose Transport Regulation in Leukemia Cells
Cristiana Caliceti, Laura Zambonin, Cecilia Prata, Francesco Vieceli Dalla Sega, Gabriele Hakim, Silvana Hrelia, Diana Fiorentini
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0041246
Abstract: GLUT1 is the predominant glucose transporter in leukemia cells, and the modulation of glucose transport activity by cytokines, oncogenes or metabolic stresses is essential for their survival and proliferation. However, the molecular mechanisms allowing to control GLUT1 trafficking and degradation are still under debate. In this study we investigated whether plasma membrane cholesterol depletion plays a role in glucose transport activity in M07e cells, a human megakaryocytic leukemia line. To this purpose, the effect of cholesterol depletion by methyl-β-cyclodextrin (MBCD) on both GLUT1 activity and trafficking was compared to that of the cytokine Stem Cell Factor (SCF). Results show that, like SCF, MBCD led to an increased glucose transport rate and caused a subcellular redistribution of GLUT1, recruiting intracellular transporter molecules to the plasma membrane. Due to the role of caveolae/lipid rafts in GLUT1 stimulation in response to many stimuli, we have also investigated the GLUT1 distribution along the fractions obtained after non ionic detergent treatment and density gradient centrifugation, which was only slightly changed upon MBCD treatment. The data suggest that MBCD exerts its action via a cholesterol-dependent mechanism that ultimately results in augmented GLUT1 translocation. Moreover, cholesterol depletion triggers GLUT1 translocation without the involvement of c-kit signalling pathway, in fact MBCD effect does not involve Akt and PLCγ phosphorylation. These data, together with the observation that the combined MBCD/SCF cell treatment caused an additive effect on glucose uptake, suggest that the action of SCF and MBCD may proceed through two distinct mechanisms, the former following a signalling pathway, and the latter possibly involving a novel cholesterol dependent mechanism.
Distributional Borel Summability of Odd Anharmonic Oscillators
Emanuela Caliceti
Physics , 1999, DOI: 10.1088/0305-4470/33/20/303
Abstract: It is proved that the divergent Rayleigh-Schrodinger perturbation expansions for the eigenvalues of any odd anharmonic oscillator are Borel summable in the distributional sense to the resonances naturally associated with the system.
Distributional Borel Summability for Vacuum Polarization by an External Electric Field
Emanuela Caliceti
Physics , 2002, DOI: 10.1063/1.1565833
Abstract: It is proved that the divergent perturbation expansion for the vacuum polarization by an external constant electric field in the pair production sector is Borel summable in the distributional sense.
Spectral theory and distributional Borel summability for the quantum Hénon-Heiles model
Emanuela Caliceti
Mathematics , 2005,
Abstract: The Borel summability in the distributional sense is established of the divergent perturbation theory for the ground state resonance of the quantum H\'enon-Heiles model.
17β-Estradiol Enhances Signalling Mediated by VEGF-A-Delta-Like Ligand 4-Notch1 Axis in Human Endothelial Cells
Cristiana Caliceti, Giorgio Aquila, Micaela Pannella, Marco Bruno Morelli, Cinzia Fortini, Paolo Pinton, Massimo Bonora, Silvana Hrelia, Antonio Pannuti, Lucio Miele, Paola Rizzo, Roberto Ferrari
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0071440
Abstract: Estrogens play a protective role in coronary artery disease. The mechanisms of action are still poorly understood, although a role for estrogens in stimulation of angiogenesis has been suggested. In several cell types, estrogens modulate the Notch pathway, which is involved in controlling angiogenesis downstream of vascular endothelial growth factor A (VEGF-A). The goal of our study was to establish whether estrogens modulate Notch activity in endothelial cells and the possible consequences on angiogenesis. Human umbilical vein endothelial cells (HUVECs) were treated with 17β-estradiol (E2) and the effects on Notch signalling were evaluated. E2 increased Notch1 processing as indicated by i) decreased levels of Notch1 transmembrane subunit ii) increased amount of Notch1 in nuclei iii) unaffected level of mRNA. Similarly, E2 increased the levels of the active form of Notch4 without altering Notch4 mRNA. Conversely, protein and mRNA levels of Notch2 were both reduced suggesting transcriptional repression of Notch2 by E2. Under conditions where Notch was activated by upregulation of Delta-like ligand 4 (Dll4) following VEGF-A treatment, E2 caused a further increase of the active form of Notch1, of the number of cells with nuclear Notch1 and of Hey2 mRNA. Estrogen receptor antagonist ICI 182.780 antagonized these effects suggesting that E2 modulation of Notch1 is mediated by estrogen receptors. E2 treatment abolished the increase in endothelial cells sprouting caused by Notch inhibition in a tube formation assay on 3D Matrigel and in mouse aortic ring explants. In conclusion, E2 affects several Notch pathway components in HUVECs, leading to an activation of the VEGF-A-Dll4-Notch1 axis and to a modulation of vascular branching when Notch signalling is inhibited. These results contribute to our understanding of the molecular mechanisms of cardiovascular protection exerted by estrogens by uncovering a novel role of E2 in the Notch signalling-mediated modulation of angiogenesis.
Stealth Properties to Improve Therapeutic Efficacy of Drug Nanocarriers
Stefano Salmaso,Paolo Caliceti
Journal of Drug Delivery , 2013, DOI: 10.1155/2013/374252
Stealth Properties to Improve Therapeutic Efficacy of Drug Nanocarriers
Stefano Salmaso,Paolo Caliceti
Journal of Drug Delivery , 2013, DOI: 10.1155/2013/374252
Abstract: Over the last few decades, nanocarriers for drug delivery have emerged as powerful tools with unquestionable potential to improve the therapeutic efficacy of anticancer drugs. Many colloidal drug delivery systems are underdevelopment to ameliorate the site specificity of drug action and reduce the systemic side effects. By virtue of their small size they can be injected intravenously and disposed into the target tissues where they release the drug. Nanocarriers interact massively with the surrounding environment, namely, endothelium vessels as well as cells and blood proteins. Consequently, they are rapidly removed from the circulation mostly by the mononuclear phagocyte system. In order to endow nanosystems with long circulation properties, new technologies aimed at the surface modification of their physicochemical features have been developed. In particular, stealth nanocarriers can be obtained by polymeric coating. In this paper, the basic concept underlining the “stealth” properties of drug nanocarriers, the parameters influencing the polymer coating performance in terms of opsonins/macrophages interaction with the colloid surface, the most commonly used materials for the coating process and the outcomes of this peculiar procedure are thoroughly discussed. 1. Introduction Cancer is a leading cause of death worldwide as accounted for 7.6 million deaths (around 13% of all deaths) in 2008 (source: WHO Fact sheet N°297 February 2012). About 70% of all cancer deaths occurred in low- and middle-income countries. Deaths caused by cancer are forecasted to rise to over 13.1 millions in 2030 (Globocan, 2008, IARC, 2010). Nevertheless, over the past few decades, significant advances have been made in fundamental cancer biology, allowing for remarkable improvements in diagnosis and therapy for cancer. Beside the development of new drugs with potent and selective activities, nanotechnology offers novel opportunities to cancer fighting by providing adequate tools for early detection and personalized treatments. Over the last decades, a number of different long circulating vehicles have been developed for theranostic purposes. These carriers are in the nanometer range size and most of them have been intended for the delivery of anticancer drugs to tissues affected by this pathology. The aim of this paper is to examine the features of “stealth” long circulating nanocarriers and the pharmacokinetic outcomes of stealthiness, and it will showcase the most investigated approaches yielding prolonged circulation of surface-engineered nanocarriers. 2. The Opsonisation
A criterion for the reality of the spectrum of PT symmetric Schroedinger operators with complex-valued periodic potentials
E. Caliceti,S. Graffi
Physics , 2008,
Abstract: Consider in $L^2(\R)$ the \Sc operator family $H(g):=-d^2_x+V_g(x)$ depending on the real parameter $g$, where $V_g(x)$ is a complex-valued but $PT$ symmetric periodic potential. An explicit condition on $V$ is obtained which ensures that the spectrum of $H(g)$ is purely real and band shaped; furthermore, a further condition is obtained which ensures that the spectrum contains at least a pair of complex analytic arcs.
Convergent Quantum Normal Forms, ${\mathcal P}{\mathcal T}$-symmetry and reality of the spectrum
Emanuela Caliceti,Sandro Graffi
Physics , 2012,
Abstract: A class of non-selfadjoint, $\PT$-symmetric operators is identified similar to a self-adjoint one, thus entailing the reality of the spectrum. The similarity transformation is explicitly constructed through the method of the quantum normal form, whose convergence (uniform with respect to the Planck constant) is proved. Further consequences of the uniform convergence of the quantum normal form are the establishment of an exact quantization formula for the eigenvalues.
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