Mitochondrial and endoplasmic reticulum stress pathways cooperate in zearalenone-induced apoptosis of human leukemic cells

<p>Abstract</p> <p>Background</p> <p>Zearalenone (ZEA) is a phytoestrogen from <it>Fusarium </it>species. The aims of the study was to identify mode of human leukemic cell death induced by ZEA and the mechanisms involved.</p> <p>Methods</p> <p>Cell cytotoxicity of ZEA on human leukemic HL-60, U937 and peripheral blood mononuclear cells (PBMCs) was performed by using 3-(4,5-dimethyl)-2,5-diphenyl tetrazolium bromide (MTT) assay. Reactive oxygen species production, cell cycle analysis and mitochondrial transmembrane potential reduction was determined by employing 2',7'-dichlorofluorescein diacetate, propidium iodide and 3,3'-dihexyloxacarbocyanine iodide and flow cytometry, respectively. Caspase-3 and -8 activities were detected by using fluorogenic Asp-Glu-Val-Asp-7-amino-4-methylcoumarin (DEVD-AMC) and Ile-Glu-Thr-Asp-7-amino-4-methylcoumarin (IETD-AMC) substrates, respectively. Protein expression of cytochrome c, Bax, Bcl-2 and Bcl-xL was performed by Western blot. The expression of proteins was assessed by two-dimensional polyacrylamide gel-electrophoresis (PAGE) coupled with LC-MS2 analysis and real-time reverse transcription polymerase chain reaction (RT-PCR) approach.</p> <p>Results</p> <p>ZEA was cytotoxic to U937 > HL-60 > PBMCs and caused subdiploid peaks and G1 arrest in both cell lines. Apoptosis of human leukemic HL-60 and U937 cell apoptosis induced by ZEA was via an activation of mitochondrial release of cytochrome c through mitochondrial transmembrane potential reduction, activation of caspase-3 and -8, production of reactive oxygen species and induction of endoplasmic reticulum stress. Bax was up regulated in a time-dependent manner and there was down regulation of Bcl-xL expression. Two-dimensional PAGE coupled with LC-MS2 analysis showed that ZEA treatment of HL-60 cells produced differences in the levels of 22 membrane proteins such as apoptosis inducing factor and the ER stress proteins including endoplasmic reticulum protein 29 (ERp29), 78 kDa glucose-regulated protein, heat shock protein 90 and calreticulin, whereas only <it>ERp29 </it>mRNA transcript increased.</p> <p>Conclusion</p> <p>ZEA induced human leukemic cell apoptosis via endoplasmic stress and mitochondrial pathway.</p

Gold Nanoshell-Decorated Silicone Surfaces for the Near-Infrared (NIR) Photothermal Destruction of the Pathogenic Bacterium E. faecalis

Catheter-related infections (CRIs) are associated with the formation of pathogenic biofilms on the surfaces of silicone catheters, which are ubiquitous in medicine. These biofilms provide protection against antimicrobial agents and facilitate the development of bacterial resistance to antibiotics. The application of photothermal agents on catheter surfaces is an innovative approach to overcoming biofilm-generated CRIs. Gold nanoshells (AuNSs) represent a promising photothermal tool, because they can be used to generate heat upon exposure to near-infrared (NIR) radiation, are biologically inert at physiological temperatures, and can be engineered for the photothermal ablation of cells and tissue. In this study, AuNSs functionalized with carboxylate-terminated organosulfur ligands were attached to model catheter surfaces and tested for their effectiveness at killing adhered Enterococcus faecalis (E. faecalis) bacteria. The morphology of the AuNSs was characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM), while the elemental composition was characterized by energy-dispersive X-ray spectroscopy (EDX) and X-ray photoelectron spectroscopy (XPS). Furthermore, optical and photothermal properties were acquired by ultraviolet–visible (UV-vis) spectroscopy and thermographic imaging with an infrared camera, respectively. Bacterial survival studies on AuNS-modified surfaces irradiated with and without NIR light were evaluated using a colony-formation assay. These studies demonstrated that AuNS-modified surfaces, when illuminated with NIR light, can effectively kill E. faecalis on silicone surfaces

Self-Assembled Monolayers Derived from Positively Charged Adsorbates on Plasmonic Substrates for MicroRNA Delivery: A Review

MicroRNA (miRNA) has emerged as a promising alternative therapeutic treatment for cancer, but its delivery has been hindered by low cellular uptake and degradation during circulation. In this review, we discuss the various methods of delivering miRNA, including viral and non-viral delivery systems such as liposomes and nanoparticles. We also examine the use of nanoparticles for miRNA-based diagnostics. We focus specifically on non-viral delivery systems utilizing coinage metals in the form of nanoparticles and the use of self-assembled monolayers (SAMs) as a method of surface modification. We review the use of SAMs for the conjugation and delivery of small noncoding ribonucleic acid (ncRNA), particularly SAMs derived from positively charged adsorbates to generate charged surfaces that can interact electrostatically with negatively charged miRNA. We also discuss the effects of the cellular uptake of gold and other plasmonic nanoparticles, as well as the challenges associated with the degradation of oligonucleotides. Our review highlights the potential of SAM-based systems as versatile and robust tools for delivering miRNA and other RNAs in vitro and in vivo and the need for further research to address the challenges associated with miRNA delivery and diagnostics