Nanoencapsulated capsaicin changes migration behavior and morphology of madin darby canine kidney cell monolayers

We have developed a drug delivery nanosystem based on chitosan and capsaicin. Both substances have a wide range of biological activities. We investigated the nanosystem’s influence on migration and morphology of Madin Darby canine kidney (MDCK-C7) epithelial cells in comparison to the capsaicin-free nanoformulation, free capsaicin, and control cells. For minimally-invasive quantification of cell migration, we applied label-free digital holographic microscopy (DHM) and single-cell tracking. Moreover, quantitative DHM phase images were used as novel stain-free assay to quantify the temporal course of global cellular morphology changes in confluent cell layers. Cytoskeleton alterations and tight junction protein redistributions were complementary analyzed by fluorescence microscopy. Calcium influx measurements were conducted to characterize the influence of the nanoformulations and capsaicin on ion channel activities. We found that both, capsaicin-loaded and unloaded chitosan nanocapsules, and also free capsaicin, have a significant impact on directed cell migration and cellular motility. Increase of velocity and directionality of cell migration correlates with changes in the cell layer surface roughness, tight junction integrity and cytoskeleton alterations. Calcium influx into cells occurred only after nanoformulation treatment but not upon addition of free capsaicin. Our results pave the way for further studies on the biological significance of these findings and potential biomedical applications, e.g. as drug and gene carriers

Molecular mechanisms of docetaxel resistance in breast cancer

Docetaxel is a chemotherapy drug used to treat breast cancer, however as with many chemotherapeutic drugs, resistance commonly occurs and the underlying molecular mechanisms of drug resistance are not fully understood. Gene regulatory mechanisms like DNA methylation, histone deacetylation and miRNA expression have been shown to play an important role in cancer drug resistance. This study investigated the role of these mechanisms in two in vitro breast cancer cell line models (MCF-7 and MDA-MB-231) of acquired docetaxel resistance. Using inhibitors to DNA methylation and histone deacetylation, response to docetaxel could be enhanced in both breast cancer cells and cDNA microarray expression analysis identified candidate genes that were re-expressed after treatment with both inhibitors, therefore being associated with docetaxel resistance. Decreased expression of one candidate gene, SERPINE1, was directly linked to docetaxel resistance whereby SERPINE1 modulation, using siRNA technology, directly altered response to docetaxel. Furthermore, miRNA expression profiling was performed in both docetaxel-sensitive and docetaxel-resistant cell lines where alterations of miRNAs were observed and associated with a docetaxel-resistant phenotype. In particular, increased expression of miR-34a was identified in docetaxel-resistant cells, which was associated with and with decreased BCL2 and cyclin D1 mRNA and protein expression in these cells. Modulation of miR-34a expression altered docetaxel response in both docetaxelsensitive and docetaxel-resistant cells, therefore identifying increased miR-34a as direct cause of docetaxel resistance in these cells. In addition, miR-34a was shown to directly target BCL2, which may present a mechanism through which miR-34a mediates docetaxel resistance. Overall, this study identified alterations in DNA methylation, histone deacetylation and miRNA expression as mechanisms through which gene expression is altered in docetaxel-resistant breast cancer cells.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Molecular mechanisms of docetaxel resistance in breast cancer

Docetaxel is a chemotherapy drug used to treat breast cancer, however as with many chemotherapeutic drugs, resistance commonly occurs and the underlying molecular mechanisms of drug resistance are not fully understood. Gene regulatory mechanisms like DNA methylation, histone deacetylation and miRNA expression have been shown to play an important role in cancer drug resistance. This study investigated the role of these mechanisms in two in vitro breast cancer cell line models (MCF-7 and MDA-MB-231) of acquired docetaxel resistance. Using inhibitors to DNA methylation and histone deacetylation, response to docetaxel could be enhanced in both breast cancer cells and cDNA microarray expression analysis identified candidate genes that were re-expressed after treatment with both inhibitors, therefore being associated with docetaxel resistance. Decreased expression of one candidate gene, SERPINE1, was directly linked to docetaxel resistance whereby SERPINE1 modulation, using siRNA technology, directly altered response to docetaxel. Furthermore, miRNA expression profiling was performed in both docetaxel-sensitive and docetaxel-resistant cell lines where alterations of miRNAs were observed and associated with a docetaxel-resistant phenotype. In particular, increased expression of miR-34a was identified in docetaxel-resistant cells, which was associated with and with decreased BCL2 and cyclin D1 mRNA and protein expression in these cells. Modulation of miR-34a expression altered docetaxel response in both docetaxelsensitive and docetaxel-resistant cells, therefore identifying increased miR-34a as direct cause of docetaxel resistance in these cells. In addition, miR-34a was shown to directly target BCL2, which may present a mechanism through which miR-34a mediates docetaxel resistance. Overall, this study identified alterations in DNA methylation, histone deacetylation and miRNA expression as mechanisms through which gene expression is altered in docetaxel-resistant breast cancer cells.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Rhenium Complexes with Visible-Light-Induced Anticancer Activity

US National Institutes of Health [CA114046

The Toxicity of Silver Nanoparticles Depends on Their Uptake by Cells and Thus on Their Surface Chemistry

A set of three types of silver nanoparticles (Ag NPs) are prepared, which have the same Ag cores, but different surface chemistry. Ag cores are stabilized with mercaptoundecanoic acid (MUA) or with a polymer shell [poly(isobutylene-alt-maleic anhydride) (PMA)]. In order to reduce cellular uptake, the polymer-coated Ag NPs are additionally modifi ed with polyethylene glycol (PEG). Corrosion (oxidation) of the NPs is quantifi ed and their colloidal stability is investigated. MUA-coated NPs have a much lower colloidal stability than PMA-coated NPs and are largely agglomerated. All Ag NPs corrode faster in an acidic environment and thus more Ag(I) ions are released inside endosomal/lysosomal compartments. PMA coating does not reduce leaching of Ag(I) ions compared with MUA coating. PEGylation reduces NP cellular uptake and also the toxicity. PMA-coated NPs have reduced toxicity compared with MUA-coated NPs. All studied Ag NPs were less toxic than free Ag(I) ions. All in all, the cytotoxicity of Ag NPs is correlated on their uptake by cells and agglomeration behavior

Enhanced expression of thioredoxin-interacting-protein regulates oxidative DNA damage and aging

The "free radical theory of aging" suggests that reactive oxygen species (ROS) are responsible for age-related loss of cellular functions and, therefore, represent the main cause of aging. Redox regulation by thioredoxin-1 (TRX) plays a crucial role in responses to oxidative stress. We show that thioredoxin-interacting protein (TXNIP), a negative regulator of TRX, plays a major role in maintaining the redox status and, thereby, influences aging processes. This role of TXNIP is conserved from flies to humans. Age-dependent upregulation of TXNIP results in decreased stress resistance to oxidative challenge in primary human cells and in Drosophila. Experimental overexpression of TXNIP in Hies shortens lifespan due to elevated oxidative DNA damage, whereas downregulation of TXNIP enhances oxidative stress resistance and extends lifespan

Fluorescence microscopy.

<p>Representative images of MDCK cells with actin or ZO-1 staining. (Nuclei: blue, ZO-1: green, Actin: red, NC: nanocapsules) (images have been contrast enhanced for better visualization in the print version)”.</p