Use of Placental MSCs and their exosomes as theragnostic agents for cancer treatment and diagnostic.

pre-print39,1 K

Human placenta-derived mesenchymal stem cells stimulate neuronal regeneration by promoting axon growth and restoring neuronal activity

In the last decades, mesenchymal stem cells (MSCs) have become the cornerstone of cellular therapy due to their unique characteristics. Specifically human placenta-derived mesenchymal stem cells (hPMSCs) are highlighted for their unique features, including ease to isolate, non-invasive techniques for large scale cell production, significant immunomodulatory capacity, and a high ability to migrate to injuries. Researchers are exploring innovative techniques to overcome the low regenerative capacity of Central Nervous System (CNS) neurons, with one promising avenue being the development of tailored mesenchymal stem cell therapies capable of promoting neural repair and recovery. In this context, we have evaluated hPMSCs as candidates for CNS lesion regeneration using a skillful co-culture model system. Indeed, we have demonstrated the hPMSCs ability to stimulate damaged rat-retina neurons regeneration by promoting axon growth and restoring neuronal activity both under normoxia and hypoxia conditions. With our model we have obtained neuronal regeneration values of 10%–14% and axonal length per neuron rates of 19-26, μm/neuron. To assess whether the regenerative capabilities of hPMSCs are contact-dependent effects or it is mediated through paracrine mechanisms, we carried out transwell co-culture and conditioned medium experiments confirming the role of secreted factors in axonal regeneration. It was found that hPMSCs produce brain derived, neurotrophic factor (BDNF), nerve-growth factor (NGF) and Neurotrophin-3 (NT-3), involved in the process of neuronal regeneration and restoration of the physiological activity of neurons. In effect, we confirmed the success of our treatment using the patch clamp technique to study ionic currents in individual isolated living cells demonstrating that in our model the regenerated neurons are electrophysiologically active, firing action potentials. The outcomes of our neuronal regeneration studies, combined with the axon-regenerating capabilities exhibited by mesenchymal stem cells derived from the placenta, present a hopeful outlook for the potential therapeutic application of hPMSCs in the treatment of neurological disorders.post-print2885 K

Caracterización de un determinante genético de Fusarium oxysporum que induce resistencia a tricotecenos en Saccharomyces cerevisiae

Tesis doctoral inédita leída en la Universidad Autónoma de Madrid, Facultad de Ciencias, Departamento de Biología Molecular, 17-12-199

Caracterizacion de un determinante genetico de Fusarium oxysporum que induce resistencia a tricotecenos en Saccharomyces cerevisiae

Centro de Informacion y Documentacion Cientifica (CINDOC). C/Joaquin Costa, 22. 28002 Madrid. SPAIN / CINDOC - Centro de Informaciòn y Documentaciòn CientìficaSIGLEESSpai

Blocakde of Smad4 in transformed keratinocytes containing a Ras oncogene leads to hyperactivation of the Ras-dependent Erk signalling pathway associated with progression to undifferentiated carcinomas

Smad4 functions as a transcription factor TGF-β signalling. We have investigated the role of Smad4 in the TGF-β1 cell responses of transformed PDV keratinocytes, wich contain a Ras oncogene, and of nontumorigenic MCA3D keratinocytes, by transfecting both cell lines with a dominant-negative Smad4 construct. Smad4 mediates TGF-β1-induced p21cip1 as growth factor. TGF-β1 activates Ras/Erk signalling activity in both cell lines. PD098059, as a specific inhibitor of MEK, disminishes TGF-β1-induced p21cip1 levels in PDV cells. PDV dominant-negative Smad4 cell transfectants, but not MCA3D transfectants, showed constitutive hyperactivation of the Ras/Erk signalling pathway, increased secretion of urokinase, higher motility properties, and a change to a fibroblastoid cell morphology associated in vivo with teh transition from a well differentiated to a pooly differentiated tumour phenotype. Infection of MCA3D control and dominant negative Smad4 cell transfectants with retroviruses carying a Ras oncogene led to enhaced p21cip1 and urokinase secreted levels, independently of TGF-β1 stimulation, that where reduced by PD098059. These results suggest that Smad4 acts inhibiting Ras-dependent Erk signalling activity in Ras-transformed Keratinocytes. Loss of Smad4 function in these cells results in hyperactivation of Erk signalling and progression to undifferentiated carcinomas

Functional blockade of Smad4 leads to a decrease in β-catenin levels and signaling activity in human pancreatic carcinoma cells

pre-prin

Involvement of the Ras/MAPK Signalling Pathway in the Modulation of Urokinase Production and Cellular Invasiveness by Transforming Growth Factor TGF-β1 in Transformed Keratinocytes

Transformed PDV keratonocytes respond to TGF-β1 by stimulating cell motility and invasiveness concomitantly to enhancement of the urokinae-type plasmiogen activator (uPA) expression/secretion. Depletion of extracellular signal-regulated kinase (EREK1,2) proteins by treatment of PDV cells with antinese oligonucleotides reduced basal uPA production and abolished stimulation of uPA secreted levels and cell motility by TGF-β1. PD098059, an inhibitor of mitogenactivated protein kinase (MAPK) kinase (MEK), decreased TGF-β1-induced uPA mRNA expression, secreted activity in a dose-dependent manner, and abrogated TGF-β1-stimulated cell motility and invasiveness. PDV-derived dominant-negative RasN17 cell transfectants secreted similar amounts of uPA and exhibited similar invasive abilities as the parental cells or control clones, but were unable to respond to TGF-β1 for stimulation of uPA-secreted levels and invasiveness. These results suggest that a Ras/MAPK transduction pathway is involved in the invasive response ot transformed keratinocytes to TGF-β1

Urokinase Expression and Binding Activity Associated With the TRansforming Growth Factor β1-Induced MIgratory and Invasive Phenotype of Mouse Epidermal Keratinocytes

Transforming growth factor b1(TGF-b1) is a stimulator of malignant progression in mouse skin carcinogenesis. TGF-b1 exerts a differential effect on cultured nontumorigenic (MCA3D cell line) and transformed (PDV cell line) keratinocytes. Whereas MCA3D cells are growth arrested and committed to die in the presence of the factor, it induces a reversible epithelial-fibroblastic conversion in PDV cells. This conversion is associated in vivo with a squamous-spindle cell carcinoma transition. Here we have investigated the role of urokinase (uPA) during malignant progression of transformed epidermal keratinocytes. We show that the levels of uPA expression/secretion, and the uPA binding activity to the cell surface, correlate with the invasive and malignant potentials of mouse epidermal cell lines. TGF-b1 enhanced uPA production, the number of uPA cell surface binding sites, and the expression of the plasminogen activator inhibitor PAI-1, in transformed PDV cells, but had no major effect on nontumorigenic MCA3D keratinocytes. Increased uPA production depended on the presence of the factor in the culture medium and occurred concomitantly to the stimulation of the migratory and invasive abilities of PDV cells. Synthetic peptides containing the amino terminal sequence of the mature mouse uPA inhibited the binding of uPA to the cell surface and decreased TGF-b1-induced cell motility and invasiveness. These results demonstrate that the uPA system mediates at least part of the migratory and invasive phenotype induced by TGF-b1 in transformed keratinocytes, and suggest a role for uPA on the changes that lead to the appearance of spindle carcinomas