Disrupting LIN28 in atypical teratoid rhabdoid tumors reveals the importance of the mitogen activated protein kinase pathway as a therapeutic target

Atypical teratoid rhabdoid tumor (AT/RT) is among the most fatal of all pediatric brain tumors. Aside from loss of function mutations in the SMARCB1 (BAF47/INI1/SNF5) chromatin remodeling gene, little is known of other molecular drivers of AT/RT. LIN28A and LIN28B are stem cell factors that regulate thousands of RNAs and are expressed in aggressive cancers. We identified high-levels of LIN28A and LIN28B in AT/RT primary tumors and cell lines, with corresponding low levels of the LIN28-regulated microRNAs of the let-7 family. Knockdown of LIN28A by lentiviral shRNA in the AT/RT cell lines CHLA-06-ATRT and BT37 inhibited growth, cell proliferation and colony formation and induced apoptosis. Suppression of LIN28A in orthotopic xenograft models led to a more than doubling of median survival compared to empty vector controls (48 vs 115 days). LIN28A knockdown led to increased expression of let-7b and let-7g microRNAs and a down-regulation of KRAS mRNA. AT/RT primary tumors expressed increased mitogen activated protein (MAP) kinase pathway activity, and the MEK inhibitor selumetinib (AZD6244) decreased AT/RT growth and increased apoptosis. These data implicate LIN28/RAS/MAP kinase as key drivers of AT/RT tumorigenesis and indicate that targeting this pathway may be a therapeutic option in this aggressive pediatric malignancy.     

Immunostimulatory oligonucleotides block allergic airway inflammation by inhibiting Th2 cell activation and IgE-mediated cytokine induction

A single treatment with a CpG-containing immunostimulatory DNA sequence (ISS) given before allergen challenge can inhibit T helper type 2 cell (Th2)-mediated airway responses in animal models of allergic asthma; however, the mechanism of this inhibition remains largely undefined. Here, we demonstrate that airway delivery of ISS before allergen challenge in Th2-primed mice acts in two distinct ways to prevent the allergic responses to this challenge. The first is to prevent induction of cytokines from allergen-specific Th2 cells, as demonstrated by the nearly complete inhibition of Th2 cytokine production, Th2-dependent functional responses, and gene induction patterns. ISS inhibits the Th2 response by rendering lung antigen-presenting cells (APCs) unable to effectively present antigen to Th2 cells, but not to Th1 cells. This loss of APC function correlates with a reduced expression of costimulatory molecules, including programmed cell death ligand (PD-L)1, PD-L2, CD40, CD80, CD86, and inducible T cell costimulator, and of major histocompatibility complex class II on CD11c(+ )APCs from the airways of ISS-treated mice. The second important action of ISS is inhibition of immunoglobulin E-dependent release of Th2 cytokines, especially interleukin 4, from basophils and/or mast cells in the airways of Th2-primed mice. Thus, inhibition by ISS of allergic responses can be explained by two novel mechanisms that culminate in the inhibition of the principal sources of type 2 cytokines in the airways.     

Toxicity of targeted therapy: Implications for response and impact of genetic polymorphisms

Targeted therapies have unique toxicity profiles. Common adverse events include rash, diarrhea, hypertension, hypothyroidism, proteinuria, depigmentation, and hepatotoxicity. Some of these toxicities are caused by on-target, mechanism-associated effects, which can be stratified as to whether or not the targets are relevant to response. Other toxicities are off-target and may be caused by the class of agent, e.g. antibody vs small molecule tyrosine kinase inhibitor, or by immune reactions or toxic metabolites. Both on- and off-target toxicities may be due to higher drug concentrations or altered end-organ sensitivity, which in turn can be a consequence of genetic polymorphisms controlling metabolism or tissue responsiveness. On-target toxicities are important to identify as some correlate with response and, hence, amelioration of these side effects is preferable to dose reduction or stopping drug. Toxicities secondary to relevant target impact may be recognized when distinct types of agents, such as antibodies and small molecule kinase inhibitors, with the same target have a similar side effect. For example, both bevacizumab and vascular endothelial growth factor receptor (VEGFR) kinase inhibitors cause hypertension; both epidermal growth factor receptor (EGFR) antibodies and kinase inhibitors cause rash; and these toxicities correlate with response. Herein we review common targeted agent-related toxicities, relevant genetic polymorphisms, and implications for response and patient management.     

Effects of process variables on the encapsulation of oil in ca-alginate capsules using an inverse gelation technique

The objective of this study was to investigate the effects of process variables on the encapsulation of oil in a calcium alginate membrane using an inverse gelation technique. A dispersion of calcium chloride solution in sunflower oil (water-in-oil emulsion) was added dropwise to the alginate solution. The migration of calcium ions to the alginate solution initiates the formation of a ca-alginate membrane around the emulsion droplets. The membrane thickness of wet capsules and the elastic modulus of dry capsules increased following first-order kinetics with an increasing curing time. An increase in the calcium chloride concentration increased the membrane thickness of wet capsules and the elastic modulus of dry capsules. An increase in the alginate concentration decreased the mean diameter of wet capsules but increased the elastic modulus of dry capsules.     

Optimizing siRNA efficacy through alteration in the target cell-adhesion substrate interaction

The clinical potential of short interfering RNA (siRNA) based therapeutics remains hindered by the challenge of delivering enough siRNA into the cytoplasm to yield a clinically relevant effect. Although much research has focused on optimizing delivery vehicles for this class of molecules, considerably less is known about the microenvironmental influences on the response of target cells to siRNA. The substrate to which cells adhere is one component of the microenvironment that can modulate cellular behavior. Here, we tested the hypothesis that modulating the properties of cellular adhesion substrates can alter siRNA efficacy. Specifically, cationic lipid complexed siRNA particles were applied to U251 cells seeded on alginate hydrogel surfaces with systematic variation in elastic modulus and integrin ligand arginine-glycine-aspartate (RGD) peptide density. These experiments revealed no change in siRNA-mediated eGFP knockdown over the elastic modulus range tested (53-133 kPa). However, an eightfold increase in RGD content of the alginate growth substrate resulted in an increase in siRNA knockdown efficacy from 25 ± 12% to 52 ± 10%, a more than twofold increase in silencing. Our results identify control of the cell-adhesion substrate interaction as a modulator of siRNA protein silencing efficacy. ? 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A 100A:2637-2643, 2012.     

Preparation, characterisation and viability of encapsulated Trichoderma harzianum UPM40 in alginate-montmorillonite clay

Microencapsulation is a process by which tiny parcels of an active ingredient are packaged within a second material for the purpose of shielding the active ingredient from the surrounding environment. This study aims to determine the ability of the microencapsulation technique to improve the viability of Trichoderma harzianum UPM40 originally isolated from healthy groundnut roots as effective biological control agents (BCAs). Alginate was used as the carrier for controlled release, and montmorillonite clay (MMT) served as the filler. The encapsulated Ca-alginate-MMT beads were characterised using Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA) and scanning electron microscopy (SEM). The FTIR results showed the interaction between the functional groups of alginate and MMT in the Ca-alginate-MMT beads. Peaks at 1595, 1420 and 1020 cm(-1) characterised alginate, and peaks at 1028 and 453 cm(-1) characterised MMT; both sets of peaks appeared in the Ca-alginate-MMT FTIR spectrum. The TGA analysis showed an improvement in the thermal stability of the Ca-alginate-MMT beads compared with the alginate beads alone. SEM analysis revealed a homogeneous distribution of the MMT particles throughout the alginate matrix. T. harzianum UPM40 was successfully encapsulated in the Ca-alginate-MMT beads. Storage analysis of the encapsulated T. harzianum UPM40 showed that the low storage temperature of 5°C resulted in significantly (p?相似文献   

Ergosterol from the soilborne fungus Ganoderma boninense

Ergosterol is the main component of the fungal membrane and is not found in plants or other microbial cells. Therefore, it can be a useful biomarker for the quantification of fungal biomass. We are now reporting the first isolation and characterisation of ergosterol from the mycelium of G. boninense. The ergosterol structure was detected by Thin Liquid Chromatography (TLC) and Ultra Performance Liquid Chromatography (UPLC) and confirmed with Gas Chromatography coupled with Mass Spectrometry (GCMS) and Nuclear Magnetic Resonance (NMR) analysis. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)