BACKGROUND: Previously, we reported that red blood cells (RBCs) stored in AS‐5 accumulated proinflammatory substances during storage. We observed in those studies that supernates from nonleukoreduced ...(NLR) RBCs reduced mean anti‐CD41a‐fluorescein isothiocyanate (FITC) fluorescence on platelets (PLTs), indicative of decreased expression of glycoprotein (GP)IIb/IIIa on the PLT membrane. The objective of this study was to determine if supernates from stored RBCs impaired PLT aggregation as a consequence of reduction in GPIIb/IIIa expression.
STUDY DESIGN AND METHODS: Leukoreduced (LR) and NLR RBC units were prepared in AS‐5 and stored at 1 to 6°C for 6 weeks. Supernates from RBC samples collected every 2 weeks were mixed with freshly collected type‐matched blood and incubated for 30 minutes at 37°C. PLTs in each incubated blood sample were evaluated for GPIIb/IIIa expression by flow cytometry and for aggregation response to collagen by whole blood aggregometry.
RESULTS: Supernates from stored NLR RBCs reduced CD41a‐FITC fluorescence on PLTs by 15% to 31%. A reduction in fluorescence was induced by supernates of RBCs stored for 14 days and increased as storage time increased. Supernates from Day 42 NLR RBCs reduced the mean amplitude of PLT aggregation by 31% compared to Day 0 supernates and lengthened the time before onset of aggregation by 21%. In addition, amplitude correlated directly and lag time correlated inversely with CD41a‐FITC fluorescence in all samples. Supernates from prestorage LR RBCs did not affect PLT CD41a‐FITC fluorescence or aggregation response.
CONCLUSIONS: Substances that decrease expression of GPIIb/IIIa and inhibit PLT aggregation accumulate in NLR RBCs. Accumulation of this material is prevented by leukoreduction.
Abstract
BACKGROUND
Glioblastoma’s origin and development is not only associated to genetic alterations, but also to epigenetic changes. Indeed, an altered expression or activity of epigenetic ...enzymes such as histone deacetylases (HDAC) has been associated to cancer stem cell activity, which has been widely described as a major feature for therapy resistance and tumor recurrence. In particular, inhibition of HDAC6 is an increasingly attractive pharmacological strategy, due to its association with low toxicity. Thus, the aim of the present study was to determine the impact of a new HDAC6-selective-inhibitor in glioblastoma and glioma stem cells.
MATERIAL AND METHODS
To test the effect of QTX compound in glioblastoma and glioma stem cell lines, cell viability after 72h of treatment was studied by MTT assay. After evaluation of IC50, QTX in vitro activity was analyzed, focusing on proliferation, apoptosis and stemness of U87-MG cell line and confirmed in a patient-derived glioma stem cell line. In vivo antitumor effect was evaluated using U87-MG cells xenografted in immunocompromised mice; after tumor formation, 5 mice were randomly selected as control group and another 5 for QTX treatment (intraperitoneal administration of 50 mg/kg; 5 days of dosing / 2 days off for 2 weeks). Mice weight was measured daily and tumor volume every two days.
RESULTS
We demonstrated that QTX reduces viability of all tested glioblastoma cells, even more greatly than normal astrocytes. Indeed, QTX diminishes proliferation and induces apoptosis in both conventional and patient-derived glioma cell lines. In particular, this effect was accompanied by a reduction of self-renewal properties of glioma stem cells. Interestingly, QTX in vitro activity was more effective comparing to the pan-inhibitor SAHA or the HDAC6-selective inhibitor Tubastatin A. Furthermore, QTX delayed tumor initiation and progression in vivo, without presenting significant side effects.
CONCLUSION
QTX compound presents a promising anti-tumor effect both in vitro and in vivo in glioblastoma, at least in part, inhibiting glioma stem cell activity.
Palabras Claves: movilidad internacional; competitividad económica, igualdad Summary: Globalization has generated international networks that enable educational mobility and cooperation for the ...equitable social development of nations. In this context, this study seeks, from statistical indexes used by the World Economic Forum (WEF) and the Organization for Economic Cooperation and Development (OECD), analyze the phenomenon of international student mobility and its impact on the economic competitiveness of countries, through the application of mathematical models such as the Spearman correlation coefficient and the Lorenz Curve. ...it is evident that there is a lack of strategies to ensure true international educational equality and the need to promote international student mobility in various geographical areas, especially in Eurasia, as well as how indispensable it is to have reliable mechanisms that collect the information required to determine which areas of interest of current mobility are. Más bien sitúa su labor en posibilitar a los estudiantes el acceso a cursar estudios en el extranjero, así como, propiciar y promover el intercambio de conocimiento, académico y de investigación, promoviendo tanto la cooperación internacional, intercultural y global como el desarrollo de capital cultural avanzado (Perrotta, 2017).
The elucidation of mechanisms involved in resistance to therapies is essential to improve the survival of patients with malignant gliomas. A major feature possessed by glioma cells that may aid their ...ability to survive therapy and reconstitute tumors is the capacity for self-renewal. We show here that glioma stem cells (GSCs) express low levels of MKP1, a dual-specificity phosphatase, which acts as a negative inhibitor of JNK, ERK1/2, and p38 MAPK, while induction of high levels of MKP1 expression are associated with differentiation of GSC. Notably, we find that high levels of MKP1 correlate with a subset of glioblastoma patients with better prognosis and overall increased survival. Gain of expression studies demonstrated that elevated MKP1 impairs self-renewal and induces differentiation of GSCs while reducing tumorigenesis in vivo. Moreover, we identified that MKP1 is epigenetically regulated and that it mediates the anti-tumor activity of histone deacetylase inhibitors (HDACIs) alone or in combination with temozolomide. In summary, this study identifies MKP1 as a key modulator of the interplay between GSC self-renewal and differentiation and provides evidence that the activation of MKP1, through epigenetic regulation, might be a novel therapeutic strategy to overcome therapy resistance in glioblastoma.
Mammalian genes frequently present allelic variants that differ in their expression levels and that, in the case of tumor suppressor genes, can be of relevance for cancer susceptibility and aging. We ...report here the characterization of a novel mouse model with increased activity for the Ink4a and Arf tumor suppressors. We have generated a "super Ink4a/Arf" mouse strain carrying a transgenic copy of the entire Ink4a/Arf locus. Cells derived from super Ink4a/Arf mice have increased resistance to in vitro immortalization and oncogenic transformation. Importantly, super Ink4a/Arf mice manifest higher resistance to cancer compared to normal, nontransgenic, mice. Finally, super Ink4a/Arf mice have normal aging and lifespan. Together, these results indicate that modest increases in the activity of the Ink4a/Arf tumor suppressor result in a beneficial cancer-resistant phenotype without affecting normal viability or aging.
Despite the importance of the INK4a/ARF locus in tumor suppression, its modulation by histone deacetylase inhibitors (HDACis) remains to be characterized. Here, we have shown that the levels of ...p16INK4a are decreased in human and murine fibroblasts upon exposure to relatively high concentrations of trichostatin A and sodium butyrate. Interestingly, the levels of p19ARF are strongly upregulated in murine cells even at low concentrations of HDACis. Using ARF-deficient cells, we have demonstrated that p19ARF plays an active role in HDACi-triggered cytostasis and the contribution of p19ARF to this arrest is of higher magnitude than that of the well established HDACi target p21Waf1/Cip. Moreover, chemically induced fibrosarcomas in ARF-null mice are more resistant to the therapeutic effect of HDACis than similar tumors in wild type or p21Waf1/Cip-null mice. Together, our results have established the tumor suppressor ARF as a relevant target for HDACi chemotherapy.
Purpose: To compare corneal endothelial cell loss with two cataract surgery techniques: manual nucleofragmentation performed with the Keener nucleus divider and planned extracapsular extraction.
...Setting: Department of Ophthalmology “Memorial Cristóbal Garrigosa,” Hospital de I'Esperaça, Universitat Autònoma de Barcelona, Spain.
Methods: Contact specular microscopy was performed before and 8 weeks after surgery in 51 patients who had been prospectively randomized into 2 groups: 26 patients had manual nucleofragmentation (NF) with the Keener divider and 25, planned extracapsular cataract extraction (ECCE). The analyzed parameters were preoperative and postoperative endothelial cell density and variations in cell size (polymegethism) and cell shape (pleomorphism). The results were compared and statistically analyzed.
Results: The mean percentage of endothelial cell loss in the NF group was 11.08% and in the ECCE group, 9.86%. This difference was not statistically significant. Postoperative variation in cell shape and size did not differ significantly between the two groups and was fairly constant.
Conclusion: The percentage of endothelial cell loss that occurred with manual NF using the Keener nucleus divider was similar to the one that occurs with other cataract surgery techniques. The small variation detected in postoperative endothelial morphology suggests that this endothelial cell population is stable.
Our group has recently derived skeletal muscle from dermis-derived cells, by using an extracellular matrix that recreates the myogenic niche. After one week of differentiation, we observed isolated, ...twitching myotubes followed by spontaneous contractions of the entire tissue-engineered muscle construct. In vitro engineered myofibers expressed canonical markers, ultrastructure and electrophysiological characteristics of skeletal muscle. Interestingly, after one-month engineered muscle constructs showed progressive degradation of the myofibers concomitant with fatty infiltration, paralleling the natural course of muscular degeneration. However, we do not yet know how dermis-resident precursors are related with our isolated-myogenic precursors, a critical point for extrapolating our results to the human system. Knowing that dermal cells and muscle cells share a common embryonic origin from somite-derived dermomyotome and taking into account that there are different types of cells within the skin that have myogenic potential, our main objective is to identify and characterize the origin of murine dermal subpopulation with a myogenic potential, hypothesizing that may be (i) satellite cells from the Panniculus carnosus, (ii) dermomyotome-derived adult stem cells, (iii) perivascular cells and/or (iv) neural crest-derived precursor cells. For this end, lineage tracing experiments (i) Pax3-GFP, (ii) Pax7CE, (iii) Myf5-Cre, (iv) CSPG4-Cre, and (v) Sox10-Cre combined with FACS strategies and cellular differentiation assays have been developed. Our results show a high contribution of Myf5+ cells, a low contribution of Cspg4+ cells, and no contribution of Sox10+ cells to dermis-derived myogenic precursor cell subset. In principle, that means that dermomyotome-derived but not neural crest-derived cells are involved in subsequent engineered muscle differentiation.
Cellular proliferation under stressful conditions may result in permanent genetic and epigenetic changes. Using primary mouse embryonic fibroblasts, we have completed a screening test to identify ...gene expression changes triggered when cells proliferate under stress. In this manner, we have discovered a novel phenomenon that consists of the rapid and coordinated silencing of genes subject to imprinting, including Cdkn1c, Igf2, H19, Ndn1, Grb10, and Meg3. This generalized silencing of imprinted genes is independent of the stress-responsive tumor suppressors p53, p19(Arf), and p16(Ink4a), and it is also independent of the oxidative culture conditions and the stress response known as "mouse embryonic fibroblast senescence". In the case of Cdkn1c and H19, their silencing is associated with unscheduled de novo methylation of the normally expressed allele at their corresponding CpG island promoters, thus resulting in biallelic methylation. Finally, we provide evidence for frequent de novo methylation of Cdkn1c in a variety of murine cancer types. Altogether, our data support the concept that silencing of imprinted genes, including methylation of Cdkn1c, constitutes an epigenetic signature of cellular stress and tumorigenesis.
PDF
