Enhanced selective sonosensitizing efficacy of ultrasound-based anticancer treatment by targeted gold nanoparticles

partially_open9noThis study investigates cancer targeted gold nanoparticles as ultrasound sensitizers for the treatment of cancer.his study investigates cancer targeted gold nanoparticles as ultrasound sensitizers for the treatment of cancer. Methods: The ultrasound sensitizer activity of folate-PEG decorated gold nanoparticles (FA-PEG-GNP) has been studied on human cancer cell lines that overexpress folate receptors (KB and HCT-116) and another that does not (MCF7), at two ultrasound energy densities (8 × 10-6 J cm-2 and 8 × 10-5 J cm-2, for 5 min at 1.866 MHz). Results: FA-PEG-GNP selectively targeted KB and HCT-116 cells and a remarkable reduction in cancer cell growth was observed upon ultrasound exposure, along with significant reactive oxygen species generation and increase in necrotic cells. Conclusion: The combined use of targeting capacity and the ultrasound sensitizing effect, make FA-PEG-GNP promising candidates for the site-specific cancer treatment. © 2016 Future Medicine Ltd.partially_openBrazzale, Chiara; Canaparo, Roberto; Racca, Luisa; Foglietta, Federica; Durando, Giovanni; Fantozzi, Roberto; Caliceti, Paolo; Salmaso, Stefano; Serpe, LoredanaBrazzale, Chiara; Canaparo, Roberto; Racca, Luisa; Foglietta, Federica; Durando, Giovanni; Fantozzi, Roberto; Caliceti, Paolo; Salmaso, Stefano; Serpe, Loredan

Influence of folate-targeted gold nanoparticles on subcellular localization and distribution into lysosomes

The cell interaction, mechanism of cell entry and intracellular fate of surface decorated nanoparticles are known to be affected by the surface density of targeting agents. However, the correlation between nanoparticles multivalency and kinetics of the cell uptake process and disposition of intracellular compartments is complicated and dependent on a number of physicochemical and biological parameters, including the ligand, nanoparticle composition and colloidal properties, features of targeted cells, etc. Here, we have carried out an in-depth investigation on the impact of increasing folic acid density on the kinetic uptake process and endocytic route of folate (FA)-targeted fluorescently labelled gold nanoparticles (AuNPs). A set of AuNPs (15 nm mean size) produced by the Turkevich method was decorated with 0–100 FA-PEG3.5kDa-SH molecules/particle, and the surface was saturated with about 500 rhodamine-PEG2kDa-SH fluorescent probes. In vitro studies carried out using folate receptor overexpressing KB cells (KBFR-high) showed that the cell internalization progressively increased with the ligand surface density, reaching a plateau at 50:1 FA-PEG3.5kDa-SH/particle ratio. Pulse-chase experiments showed that higher FA density (50 FA-PEG3.5kDa-SH molecules/particle) induces more efficient particle internalization and trafficking to lysosomes, reaching the maximum concentration in lysosomes at 2 h, than the lower FA density of 10 FA-PEG3.5kDa-SH molecules/particle. Pharmacological inhibition of endocytic pathways and TEM analysis showed that particles with high folate density are internalized predominantly by a clathrin-independent process

Switching of macromolecular ligand display by thermoresponsive polymers mediates endocytosis of multi-conjugate nanoparticles

Ligand-mediated targeting and internalization of plasma membrane receptors is central to cellular function. These types of receptors have accordingly been investigated as targets to facilitate entry of diagnostic and therapeutic constructs into cells. However, there remains a need to characterize how receptor targeting agents on nanoparticles interact at surface receptors and whether it is possible to control these interactions via exogenous stimuli. Here, we describe the switchable display of the iron-transporting protein, transferrin (Tf), at the surface of thermoresponsive polymer-coated gold nanoparticles, and show that internalization of the coated nanoparticles into target cells changes across temperature ranges over which transferrin is expected to be sterically ‘hidden’ by an extended polymer chain and then ‘revealed’ by polymer chain collapse. The switching process is dependent on the numbers of transferrin molecules and thermoresponsive polymer chains attached, and whether the assay temperature is above or below the transition temperatures of the responsive polymers at the nanoparticle surfaces. Significantly, however, the control of internalization is critically reliant on overall nanoparticle colloidal stability while the thermoresponsive component of the surface undergoes conformational change. The data show that the cell entry function of complex and large biomolecule ligands can be modulated by polymer-induced accessibility change, but that a simple ‘hide and reveal’ mechanism for ligand display following polymer chain collapse is insufficient to account for nanoparticle uptake and subsequent intracellular trafficking

Muon reconstruction performance of the ATLAS detector in proton–proton collision data at √s = 13 TeV

This article documents the performance of the ATLAS muon identification and reconstruction using the LHC dataset recorded at √s = 13 TeV in 2015. Using a large sample of J/ψ→μμ and Z→μμ decays from 3.2 fb−1 of pp collision data, measurements of the reconstruction efficiency, as well as of the momentum scale and resolution, are presented and compared to Monte Carlo simulations. The reconstruction efficiency is measured to be close to 99% over most of the covered phase space (|η| 2.2, the pT resolution for muons from Z→μμ decays is 2.9 % while the precision of the momentum scale for low-pT muons from J/ψ→μμ decays is about 0.2%

Constraints on new phenomena via Higgs boson couplings and invisible decays with the ATLAS detector

Abstract: The ATLAS experiment at the LHC has measured the Higgs boson couplings and mass, and searched for invisible Higgs boson decays, using multiple production and decay channels with up to 4.7 fb−1 of pp collision data at−1at TeV. In the current study, the measured production and decay rates of the observed Higgs boson in the γγ, ZZ, W W , Zγ, bb, τ τ , and μμ decay channels, along with results from the associated production of a Higgs boson with a top-quark pair, are used to probe the scaling of the couplings with mass. Limits are set on parameters in extensions of the Standard Model including a composite Higgs boson, an additional electroweak singlet, and two-Higgs-doublet models. Together with the measured mass of the scalar Higgs boson in the γγ and ZZ decay modes, a lower limit is set on the pseudoscalar Higgs boson mass of mA> 370 GeV in the “hMSSM” simplified Minimal Supersymmetric Standard Model. Results from direct searches for heavy Higgs bosons are also interpreted in the hMSSM. Direct searches for invisible Higgs boson decays in the vector-boson fusion and associated production of a Higgs boson with W/Z (Z → ℓℓ, W/Z → jj) modes are statistically combined to set an upper limit on the Higgs boson invisible branching ratio of 0.25. The use of the measured visible decay rates in a more general coupling fit improves the upper limit to 0.23, constraining a Higgs portal model of dark matter.[Figure not available: see fulltext.

Search for pair and single production of new heavy quarks that decay to a Z boson and a third-generation quark in pp collisions at √s = 8TeV with the ATLAS detector

A search is presented for the production of new heavy quarks that decay to a Z boson and a third-generation Standard Model quark. In the case of a new charge +2/3 quark (T), the decay targeted is T -> Zt, while the decay targeted for a new charge -1/3 quark (B) is B -> Zb. The search is performed with a dataset corresponding to 20.3 fb(-1) of p p collisions at root s = 8TeV recorded in 2012 with the ATLAS detector at the CERN Large Hadron Collider. Selected events contain a high transverse momentum Z boson candidate reconstructed from a pair of oppositely charged same-flavor leptons (electrons or muons), and are analyzed in two channels defined by the absence or presence of a third lepton. Hadronic jets, in particular those with properties consistent with the decay of a b-hadron, are also required to be present in selected events. Different requirements are made on the jet activity in the event in order to enhance the sensitivity to either heavy quark pair production mediated by the strong interaction, or single production mediated by the electroweak interaction. No significant excess of events above the Standard Model expectation is observed, and lower limits are derived on the mass of vector-like T and B quarks under various branching ratio hypotheses, as well as upper limits on the magnitude of electroweak coupling parameters

Sviluppo di sistemi nanoparticellari per il direzionamento multimodale al tumore

Sviluppo di nanocarries per il direzionamento multimodale selettivo verso il tumor

Gold nanoparticle surface tuning for multimodal treatment of cancer

In the last decades colloidal decorated gold nanoparticles (GNPs) have been studied as platform for drug and gene delivery, for diagnostic and other biomedical applications. These metal nanoparticles are intriguing because of their unique physico-chemical properties that can be exploited for multimodal and combined treatment of cancer. In the present thesis work gold nanoparticles were decorated with a targeting ligand (Folate-PEG) to combine an active and a passive targeting aiming to enhance the selective accumulation within the tumour site. Deep studies have been done to investigate the effect of surface Folate density on the internalization efficiency of gold nanoparticles. Afterwards intracellular trafficking studies were performed to clarify the uptake mechanism and investigate lysosomal delivery. Confocal microscopy and TEM analysis showed in good agreement that Folate targeted gold nanoparticles are internalized via a clathrin-independent pathway. Another purpose of the project have concerned the exploitation of GNPs as sensitizers in the sonodynamic therapy. This is a non-invasive approach which consists in cancer tissue irradiation with focused ultrasounds (HIFU) to trigger cavitation phenomena leading to irreversible destruction of the target tissue. The combination of the ultrasound exposure and the pre-incubation of cells with Folate targeted particles induced a significant and selective cell death. The concept of multimodal targeting was extended to the development of pH responsive targeted gold nanoparticles, using a pH sensitive polymer able to respond with morphological alterations to environmental pH changes. The cell uptake results confirmed that the “hiding” and “reveal” of targeting agents on GNP surface is modulated by the sensitive polymer. As a result there is an enhanced site-selective GNP accumulation in the cancer tissue, according to a cooperative exploitation of phenotypic and environmental features of the tumour. In conclusion, the present thesis work is proposed as proof-of-concept to show that by finely tuning the surface properties of nanosystems, site-selectivity can be significantly enhanced, thus reducing the disposition of drug nanocarriers in off-target tissues.Lo scopo del presente progetto di dottorato è stato quello di produrre e caratterizzare dal punto di vista chimico-fisico e biologico un nanocarrier per il direzionamento selettivo di farmaci antitumorali a tumori sovraesprimenti il recettore per l’acido folico. Sono stati compiuti studi approfonditi per verificare come la densità dell’agente di targeting influenzasse l’efficienza d’internalizzazione del sistema. Inoltre studi di trafficking intracellulare hanno verificato come particelle d’oro direzionate con agente di targeting Folato-PEG vengano internalizzate mediante meccanismo clatrina-indipendente. Si è inoltre indagata la capacità di nanoparticelle d’oro come sensibilizzanti alla terapia sonodinamica al fine di poter combinare un trattamento farmacologico ad un approccio fisico. Un ulteriore sviluppo del progetto ha riguardato la modifica di nanoparticelle d’oro direzionate con Folato-PEG con una seconda componente pH responsiva in grado di passare da una conformazione estesa a pH fisiologico di 7.4 ad una forma idrofobica globulare a pH 6.5, condizione tipica del tessuto tumorale. In questo modo é possibile modulare il mascheramento/esposizione dell’agente di targeting e ridurre il bio-riconoscimento aspecifico a favore della sito-specificità. Tra gli sviluppi futuri del progetto, vi è la decorazione di nanoparticelle d’oro con un polimero dotato di gruppi idrazinici coniugati a Doxorubicina mediante legame idrazonico. In virtù delle proprietà del legame idrazonico, la Doxorubicina sarà rilasciata esclusivamente nei comparti endosomiali e lisosomiali, in seguito all'uptake cellulare mediato dal recettore FR per l’acido folico

pH-sensitive stearoyl-PEG-poly(methacryloyl sulfadimethoxine) decorated liposomes for the delivery of gemcitabine to cancer cells.

Novel, acid-sensitive liposomes that respond to physiopathological pH for tumour targeting applications were obtained by surface decoration with 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[methoxy(polyethylene glycol)] (mPEG-DSPE) and stearoyl-poly(ethylene glycol)-poly(methacryloyl sulfadimethoxine) copolymer (stearoyl-PEG-polySDM). The pH-sensitive stearoyl-PEG-polySDM copolymer contained an average of seven methacryloyl sulfadimethoxines per molecule and was found to possess an apparent pKa of 7.2. Preliminary cloud point studies showed that the hydrophilic/hydrophobic copolymer conversion occurred at pH 7.0. The copolymer was soluble above pH 7.0 and underwent aggregation at lower pH. Liposome formulations were prepared with 0.2:0.6:100, 0.5:1.5:100 and 1:3:100 mPEG-DSPE/stearoyl-PEG-polySDM/lipids molar ratios. All of the liposome formulations were stable at pH 7.4, even in the presence of foetal bovine serum, but they underwent rapid size increase at pH 6.5. TEM analysis showed that, at pH 6.5, the formulations coated with a stearoyl-PEG-polySDM/lipids molar ratio greater than 1:100 underwent aggregation. At pH 7.4, the liposomes showed negative zeta potential that significantly decreased after incubation at pH 6.5. Cell-culture studies indicated that the liposomes were not toxic up to 10mg/mL. Fluorescence spectroscopy, cytofluorimetry and confocal microscopy showed that at pH 6.5, the incubation of MCF-7 tumour cells with fluorescein-labelled 1:3:100 mPEG-DSPE/stearoyl-PEG-polySDM/lipids molar ratio liposomes resulted in time-dependent cell association, while at pH 7.4 the cell interaction was significantly lower. The same pH-responsive liposome formulation loaded with gemcitabine (98.2\ub14.7nmol gemcitabine/lipid \u3bcmol loading capacity) was stable at pH 7.4 for several hours, while at pH 6.5 it rapidly aggregated. At pH 6.5, these liposomes displayed higher cytotoxicity than at pH 7.4 or compared to non-responsive control liposomes at both incubation pH. Notably, treatment with free gemcitabine did not yield cytotoxic effects, indicating that the carrier can efficiently deliver the anticancer drug to the cytosolic compartment