1,721,171 research outputs found
The extracellular matrix in neural crest-cell migration
No full textThe peripheral nervous system is created by a spatiotemporally co-ordinated migratory process during which the precursor cells, the neural crest (NC) cells, transverse the embryo to reach distantly located sites. Original transplantation experiments implicated the extracellular matrix (ECM) as a pivotal factor in the regulation of this process, and subsequent in vitro and in vivo studies have uncovered a number of ECM molecules potentially responsible for the NC cell-ECM interaction. Recent genetic manipulations in mice sustain the importance of certain matrix constituents, while precluding a significant role for others and, surprisingly, for all primary integrin receptors expressed by NC cells. The gradually crystallizing paradigm envisions that guidance of the disseminating NC cells, as well as the arrest at their final tissue locations, is governed by specific 'inhibitory' ECM-associated signals. This implies that homing of peripheral neurons and their supportive cells might be dictated by a delicate equilibrium between the multiple actions of stimulatory and inhibitory molecules, which is modulated further by defined responses of the dispersing cells to these ECM components during their successive phases of phenotypic diversification
Prognostic/predictive biomarkers of oral carcinomas: are we ready to move into the clinics ?
No full textCell origin of tumours and the persistence of cancer propagatine cells in tumour lesions
No full textApproaching the Proteoglycome: Molecular interactions of proteoglycans and their functional output
No full textThrough their diverse core protein modules and glycan/glycosaminoglycan moieties, proteoglycans may engage in numerous cellular and molecular interactions which are dispensable during embryogenesis, are essential for the maintenance of a healthy state and are prone to modulation in pathological conditions. Proteoglycan interactions may involve binding to other structural components of the ECM, to cell surface receptors, to membrane-associated components, and to soluble signaling molecules, which through this interaction may become entrapped in the ECM or sequestered at the cell surface. Understanding of these multiple interplays is therefore of paramount importance and requires a detailed mapping through what we define as the proteoglycome. © 2006 Wiley-VCH Verlag GmbH & Co. KGaA
Embryonic extracellular matrix adsorbed in vivo onto microcarriers induces expression of chromatophore phenotypes in cultured neural crest cells
No full textInstructive induction or permissive activation? Differentiation of ectodermal cells isolated from the axolotl blastula
No full textPrevious observations indicate that the cell differentiations associated with induction in the amphibian embryo may involve a permissive activation rather than an instructive induction. We have studied this process in small explants isolated from the axolotl blastula and cultured in vitro. It was previously found that Li+ and heparan sulphate ensure the differentiation of animal ectodermal cells into neural crest cells. In the present paper we show that this same effect may be achieved by the addition of ouabain, the calcium ionophore A 23187, the potassium ionophore valinomycin, cyclic AMP and cyclic GMP, prostaglandin E1, and glucagon. It was also observed that the substances need to be present for as little as 10 min, and must be added within 6-7 h from the time of isolatoin in order to exert their effect. We report some observations on sulphated polysaccharides, which are strong activators of the differentiation of ectodermal cells. Weak ionic currents are of great importance for various cellular events, including cell differentiations. Inhibitors of these currents have been found to inhibit the differentiation of ectodermal cells initiated by heparan sulphate. If the 'induction' of the ectodermal cells is really an activation, then it follows that they must be induced to form epidermis. Various facts suggest that the tonicity of the medium is a decisive factor in this process, the induction being promoted by low ion concentrations. © 1983
Inhibition of neural crest cell migration by aggregating chondroitin sulfate proteoglycans is mediated by their hyaluronan-binding region
No full text"Destemming" cancer stem cells.
No full textAbstract
Cancer stem cells have been variously defined as cells within a cancer that have the exclusive ability to self-renew and to differentiate into the heterogeneous lineages of cancer cells that comprise the tumor. Interest in cancer stem cells is currently high, arising from recent reports identifying cell surface markers that can be used to sort such cells from primary human tumors. However, use of the term cancer stem cell may be misleading. A better term might be cancer-initiating cells because it remains to be demonstrated that cancer stem cells have the properties that define normal stem cells, including multipotency and the ability to undergo asymmetric and symmetric divisions. Many properties of cancer stem cells remain unclear, particularly the stability of their phenotype. These uncertainties must be considered in the development and testing of compounds targeted against putative cancer stem cells. Tumors apparently contain very few cancer stem cells, so that when tests of compounds targeted to such cells are designed, short-term response trials may not be informative and long-term trials must be planned, particularly if the drugs could also kill normal stem cells
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