Mesenchymal Stem Cells Promote Mammosphere Formation and Decrease E-Cadherin in Normal and Malignant Breast Cells

Normal and malignant breast tissue contains a rare population of multi-potent cells with the capacity to self-renew, referred to as stem cells, or tumor initiating cells (TIC). These cells can be enriched by growth as "mammospheres" in three-dimensional cultures.We tested the hypothesis that human bone-marrow derived mesenchymal stem cells (MSC), which are known to support tumor growth and metastasis, increase mammosphere formation.We found that MSC increased human mammary epithelial cell (HMEC) mammosphere formation in a dose-dependent manner. A similar increase in sphere formation was seen in human inflammatory (SUM149) and non-inflammatory breast cancer cell lines (MCF-7) but not in primary inflammatory breast cancer cells (MDA-IBC-3). We determined that increased mammosphere formation can be mediated by secreted factors as MSC conditioned media from MSC spheroids significantly increased HMEC, MCF-7 and SUM149 mammosphere formation by 6.4 to 21-fold. Mammospheres grown in MSC conditioned media had lower levels of the cell adhesion protein, E-cadherin, and increased expression of N-cadherin in SUM149 and HMEC cells, characteristic of a pro-invasive mesenchymal phenotype. Co-injection with MSC in vivo resulted in a reduced latency time to develop detectable MCF-7 and MDA-IBC-3 tumors and increased the growth of MDA-IBC-3 tumors. Furthermore, E-cadherin expression was decreased in MDA-IBC-3 xenografts with co-injection of MSC.MSC increase the efficiency of primary mammosphere formation in normal and malignant breast cells and decrease E-cadherin expression, a biologic event associated with breast cancer progression and resistance to therapy

The effect of affective characterizations on the use of size and colour in drawings produced by children in the absence of a model

Previous studies have revealed that children increase the size of drawings of topics about which they feel positively and use their most preferred colours for colouring in these drawings, and decrease the size of topics about which they feel negatively and use their least preferred colours for colouring in these drawings. However, these previous findings have been obtained in studies employing drawing tasks where planning and production difficulties have been minimised by asking the children either to copy or to colour in an outline stimulus of a figure provided by the experimenter. The present experiment was designed to examine whether children also alter the use of size and colour in their drawings in response to emotional characterisations when they are not constrained by the presence of a model. Two hundred and fifty three children aged between 4 and 11 years were asked to produce drawings of a neutrally, a positively and a negatively characterised topic (either a man, a dog or a tree). It was found that the children consistently increased the size of the positively characterised figures, did not consistently decrease the size of the negatively characterised figures, used their most preferred colours for the positive figures, and used their least preferred colours for the negative figures. These findings are discussed in relation to the operation of an appetitive-defensive mechanism and pictorial conventions