Search results for "NANOG"

Multiple Pluripotent Stem Cell Markers in Human Anaplastic Thyroid Cancer: The Putative Upstream Role of SOX2

2013

Anaplastic thyroid carcinoma (ATC) is a rare and aggressive endocrine tumor with highly undifferentiated morphology. It has been suggested that cancer stem cells (CSCs) might play a central role in ATC. The objectives of this study were (i) to characterize CSCs from ex vivo ATC specimens by investigating the expression of several pluripotent stem cell markers, and (ii) to evaluate in vitro drug resistance modifications after specific CSC transcription factor switch-off.In ex vivo experiments, eight formalin-fixed, paraffin-embedded ATC specimens were analyzed by reverse-transcription and real-time quantitative PCR and immunohistochemistry. In in vitro experiments using ATC SW1736 cells, the…

Composite nanoparticles based on hyaluronic acid chemically cross-linked with alpha,beta-polyaspartylhydrazide.

2007

In this paper, new composite nanoparticles based on hyaluronic acid (HA) chemically cross-linked with alpha,beta polyaspartylhydrazide (PAHy) were prepared by the use of a reversed-phase microemulsion technique. HA-PAHy nanoparticles were characterized by FT-IR spectroscopy, confirming the occurrence of the chemical cross-linking, dimensional analysis, and transmission electron micrography, showing a sub-micrometer size and spherical shape. Zeta potential measurements demonstrated the presence of HA on the nanoparticle surface. A remarkable affinity of the obtained nanoparticles toward aqueous media that simulate some biological fluids was found. Stability studies showed the absence of chem…

Size-dependent knockdown potential of siRNA-loaded cationic nanohydrogel particles.

2014

To overcome the poor pharmacokinetic conditions of short double-stranded RNA molecules in RNA interference therapies, cationic nanohydrogel particles can be considered as alternative safe and stable carriers for oligonucleotide delivery. For understanding key parameters during this process, two different types of well-defined cationic nanohydrogel particles were synthesized, which provided nearly identical physicochemical properties with regards to their material composition and resulting siRNA loading characteristics. Yet, according to the manufacturing process using amphiphilic reactive ester block copolymers of pentafluorophenyl methacrylate (PFPMA) and tri(ethylene glycol)methyl ether m…

Minimalism in radiation synthesis of biomedical functional nanogels.

2012

A scalable, single-step, synthetic approach for the manufacture of biocompatible, functionalized micro- and nanogels is presented. In particular, poly(N-vinyl pyrrolidone)-grafted-(aminopropyl)methacrylamide microgels and nanogels were generated through e-beam irradiation of PVP aqueous solutions in the presence of a primary amino-group-carrying monomer. Particles with different hydrodynamic diameters and surface charge densities were obtained at the variance of the irradiation conditions. Chemical structure was investigated by different spectroscopic techniques. Fluorescent variants were generated through fluorescein isothiocyanate attachment to the primary amino groups grafted to PVP, to …

Reactive Self-Assembly and Specific Cellular Delivery of NCO-sP(EO-stat-PO)-Derived Nanogels

2018

This study presents the reactive self-assembly of isocyanate functional and amphiphilic six-arm, star-shaped polyether prepolymers in water into nanogels. Intrinsic molecular amphiphilicity, mainly driven by the isophorone moiety at the distal endings of the star-shaped molecules, allows for the preparation of spherical particles with an adjustable size of 100-200 nm by self-assembly and subsequent covalent cross-linking without the need for organic solvents or surfactants. Covalent attachment of a fluorescence dye and either the cell-penetrating TAT peptide or a random control peptide sequence shows that only TAT-labeled nanogels are internalized by HeLa cells. The nanogels thus specifical…

Squaric Ester-Based, pH-Degradable Nanogels: Modular Nanocarriers for Safe, Systemic Administration of Toll-like Receptor 7/8 Agonistic Immune Modula…

2021

Small-molecular Toll-like receptor 7/8 (TLR7/8) agonists hold promise as immune modulators for a variety of immune therapeutic purposes including cancer therapy or vaccination. However, due to their rapid systemic distribution causing difficult-to-control inflammatory off-target effects, their application is still problematic, in particular systemically. To address this problem, we designed and robustly fabricated pH-responsive nanogels serving as versatile immunodrug nanocarriers for safe delivery of TLR7/8-stimulating imidazoquinolines after intravenous administration. To this aim, a primary amine-reactive methacrylamide monomer bearing a pendant squaric ester amide is introduced, which i…

Osteogenic commitment and differentiation of human mesenchymal stem cells by low‐intensity pulsed ultrasound stimulation

2018

Low-intensity pulsed ultrasound (LIPUS) as an adjuvant therapy in in vitro and in vivo bone engineering has proven to be extremely useful. The present study aimed at investigating the effect of 30 mW/cm(2) LIPUS stimulation on commercially available human mesenchymal stem cells (hMSCs) cultured in basal or osteogenic medium at different experimental time points (7d, 14d, 21d). The hypothesis was that LIPUS would improve the osteogenic differentiation of hMSC and guarantying the maintenance of osteogenic committed fraction, as demonstrated by cell vitality and proteomic analysis. LIPUS stimulation (a) regulated the balance between osteoblast commitment and differentiation by specific network…

Inorganic/organic hybrid nanoparticles synthesized in a two-step radiation-driven process

2022

In this work, we have synthesized inorganic-organic hybrid nanoparticles via radiation synthesis of inorganic nanoparticles (Ag and CeO2) in aqueous dispersions containing radiation-synthesized poly(N-vinyl pyrrolidone) (PVP) nanogels (NG). The experiments show that there are strong interactions between the inorganic precursors (Ag+ and Ce3+) and the nanogel prior to irradiation. The two hybrid systems (Ag/NG and CeO2/NG) were characterized using X-ray diffraction (XRD) and transmission electron microscopy (TEM). XRD confirms the formation of crystalline Ag and CeO2. TEM reveals that the inorganic nanoparticles are evenly distributed in/on the nanogel. Both XRD and TEM show that size of the…

Crosslinking of poly(vinylpyrrolidone) activated by electrogenerated hydroxyl radicals: a first step towards a simple and cheap synthetic route of na…

2016

A facile electrosynthesis route for the preparation of polymer nanogels based on the in situ production of hydroxyl radicals is reported for the first time. Electro-Fenton process with continuous H2O2 electrogeneration and Fe2+ regeneration performs better than electro-oxidation with a boron-doped diamond or dimensionally stable anode for promoting crosslinking of poly(vinylpyrrolidone). Keywords: Electrogenerated hydroxyl radicals, BDD, DSA, Electro-Fenton, Polymer modification, Nanogel

2013

MicroRNAs of the miR-302 cluster are involved in early embryonic development and somatic cell reprogramming. Expression of the miR-302 gene is regulated by the binding of the pluripotency factors Oct4, Sox2 and Nanog to the miR-302 promoter. The specific expression pattern of the miR-302 gene suggested that additional transcription factors might be involved in its regulation. Here, we show that the miR-302 promoter is a direct target of the Wnt/β-catenin signaling pathway. We found that the miR-302 promoter contains three different functional Tcf/Lef binding sites. Two of the three sites were located within the cluster of Oct4/Sox2/Nanog binding sites and were essential for Wnt/β-catenin-me…