Granada, Spain
Granada, Spain
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Sanchez L.,GENYO | Gutierrez-Aranda I.,GENYO | Ligero G.,GENYO | Martin M.,Hospital Virgen Of La Victoria | And 5 more authors.
Tissue Engineering - Part C: Methods | Year: 2012

Despite the improvements in the human embryonic stem cell (hESC) culture systems, very similar conditions to those used to maintain hESCs on mouse feeders are broadly applied to culture methods based on human feeders. Indeed, basic fibroblast growth factor (bFGF), a master hESC-sustaining factor, is still added in nearly all medium formulations for hESC propagation. Human foreskin fibroblasts (HFFs) and mesenchymal stem cells (MSCs) used as feeders have recently been reported to support hESC growth without exogenous bFGF. However, whether hESCs may be maintained undifferentiated without exogenous bFGF using media conditioned (CM) by human feeders remains elusive. We hypothesize that HFFs and hMSCs are likely to be functionally different and therefore the mechanisms by which HFF-CM and MSC-CM support undifferentiated growth of hESCs may differ. We have thus determined whether HFF-CM and/or MSC-CM sustain feeder-free undifferentiated growth of hESC without exogenous supplementation of bFGF. We report that hMSCs synthesize higher levels of endogenous bFGF than HFFs. Accordingly and in contrast to HFF-CM, MSC-CM produced without the addition of exogenous bFGF supports hESC pluripotency and culture homeostasis beyond 20 passages without the need of bFGF supplementation. hESCs maintained without exogenous bFGF in MSC-CM retained hESC morphology and expression of pluripotency surface markers and transcription factors, formed teratomas, and showed spontaneous and lineage-directed in vitro differentiation capacity. Our data indicate that MSC-CM, but not HFF-CM, provides microenvironment cues supporting feeder-free long-term maintenance of pluripotent hESCs and obviates the requirement of exogenous bFGF at any time. © 2012, Mary Ann Liebert, Inc.

Granados-Principal S.,Biomedical Research Center | Granados-Principal S.,Jose Mataix Institute of Nutrition and Food Technology | El-Azem N.,Biomedical Research Center | El-Azem N.,Jose Mataix Institute of Nutrition and Food Technology | And 14 more authors.
Biochemical Pharmacology | Year: 2014

Oxidative stress is involved in several processes including cancer, aging and cardiovascular disease, and has been shown to potentiate the therapeutic effect of drugs such as doxorubicin. Doxorubicin causes significant cardiotoxicity characterized by marked increases in oxidative stress and mitochondrial dysfunction. Herein, we investigate whether doxorubicin-associated chronic cardiac toxicity can be ameliorated with the antioxidant hydroxytyrosol in rats with breast cancer. Thirty-six rats bearing breast tumors induced chemically were divided into 4 groups: control, hydroxytyrosol (0.5 mg/kg, 5 days/week), doxorubicin (1 mg/kg/week), and doxorubicin plus hydroxytyrosol. Cardiac disturbances at the cellular and mitochondrial level, mitochondrial electron transport chain complexes I-IV and apoptosis-inducing factor, and oxidative stress markers have been analyzed. Hydroxytyrosol improved the cardiac disturbances enhanced by doxorubicin by significantly reducing the percentage of altered mitochondria and oxidative damage. These results suggest that hydroxytyrosol improve the mitochondrial electron transport chain. This study demonstrates that hydroxytyrosol protect rat heart damage provoked by doxorubicin decreasing oxidative damage and mitochondrial alterations. © 2014 Elsevier Inc.

Rosu-Myles M.,Biologics | McCully J.,Biologics | Fair J.,University of Ottawa | Mehic J.,Biologics | And 3 more authors.
Stem Cells and Development | Year: 2013

The therapeutic potential of multipotent stromal cells (MSC) may be enhanced by the identification of markers that allow their discrimination and enumeration both in vivo and in vitro. Here, we investigated the ability of embryonic stem cell-associated glycosphingolipids to isolate human MSC from both whole-bone-marrow (BM) and stromal cell cultures. Only SSEA-4 was consistently expressed on cells within the CD45loCD105hi marrow fraction and could be used to isolate cells with the capacity to give rise to stromal cultures containing MSC. Human stromal cultures, generated in either the presence or absence of serum, contained heterogeneous cell populations discriminated by the quantity of SSEA-4 epitopes detected on their surface. A low level of surface SSEA-4 (SSEA-4lo) correlated with undetectable levels of the α2,3- sialyltransferase-II enzyme required to synthesize SSEA-4; a reduced proliferative potential; and the loss of fat-, bone-, and cartilage-forming cells during long-term culture. In vitro, single cells with the capacity to generate multipotent stromal cultures were detected exclusively in the SSEA-4hi fraction. Our data demonstrate that a high level of surface epitopes for SSEA-4 provides a definitive marker of MSC from human BM. © 2013 Mary Ann Liebert, Inc.

Garcia-Alegria E.,University of Cantabria | Garcia-Alegria E.,University of Manchester | Lafita-Navarro M.C.,University of Cantabria | Aguado R.,Stem Cells And Cancer Group Imim | And 8 more authors.
Cancer Letters | Year: 2016

Chronic myeloid leukemia (CML) progresses from a chronic to a blastic phase, where the leukemic cells are proliferative and undifferentiated. The CML is nowadays successfully treated with BCR-ABL kinase inhibitors as imatinib and its derivatives. NUMB is an evolutionary well-conserved protein initially described as a functional antagonist of NOTCH function. NUMB is an endocytic protein associated with receptor internalization, involved in multiple cellular functions. It has been reported that MSI2 protein, a NUMB inhibitor, is upregulated in CML blast crisis, whereas NUMB itself is downregulated. This suggest that NUMB plays a role in the malignant progression of CML. Here we have generated K562 cells (derived from CML in blast crisis) constitutively expressing a dominant negative form of NUMB (dnNUMB). We show that dnNUMB expression confers a high proliferative phenotype to the cells. Importantly, dnNUMB triggers a partial resistance to imatinib in these cells, antagonizing the apoptosis mediated by the drug. Interestingly, imatinib resistance is not linked to p53 status or NOTCH signaling, as K562 lack p53 and imatinib resistance is reproduced in the presence of NOTCH inhibitors. Taken together, our data support the hypothesis that NUMB activation could be a new therapeutic target in CML. © 2016.

This breakthrough may allow the use of hybrid metal-DNA molecules for applications in the fields of biotechnology and biomedicine, given that the DNA structure remains practically unaltered and the metallic ions offer new properties to DNA molecules, including fluorescence, conductivity, magnetism or catalytic properties. The research, published in Angewandte Chemie, has been conducted in the department of Inorganic Chemistry at the UGR. The formation of these metal-DNA hybrids has been achieved carrying out slight chemical modifications in some of the DNA molecules' components—in particular, replacing adenine units with 7-deazaadenine units, which maintains their auto-recognition properties and facilitates the incorporation of metallic ions. The research team from the UGR has transformed Watson-Crick bondings into similar bondings with silver metallic ions. This creates hybrid, highly stable DNA molecules capable of holding metallic ions in specific controlled positions within the DNA molecules. As a result, for the first time, researchers can obtain big DNA molecules that keep their base complementarity, and whose metallic ions are distributed along the whole DNA molecule. As professor Miguel A. Galindo Cuesta explains, "Until now, the international scientific community had only managed to introduce a small amount of metallic ions in some sections of the DNA structure using sophisticated chemical alterations that made it lose its natural properties, thus limiting possible applications." The research team is currently expanding this strategy in collaboration with Javier Martínez from the Centre for Genomics and Oncological Research (GENyO), in order to prepare metal-DNA, nanometric systems with well-defined structures by using enzymatic DNA replication methods. The goal is to develop metal-DNA hybrids with potential biotechnological applications aimed at medicine and nanotechnology. Explore further: New class of catalysts to transform cheap, widely available hydrocarbons into industrial molecules More information: Noelia Santamaría-Díaz et al. Highly Stable Double-Stranded DNA Containing Sequential Silver(I)-Mediated 7-Deazaadenine/Thymine Watson-Crick Base Pairs, Angewandte Chemie International Edition (2016). DOI: 10.1002/anie.201600924

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