The microenvironment hosting the tumor also actively participates learn more in regulating tumor cell proliferation, migration, and invasion. Among the extracellular matrix proteins enriched in stroma of carcinomas are the tenascin family members tenascin-C and tenascin-W. Whereas tenascin-C overexpression in gliomas has been widely reported to correlate with adverse prognosis, the status of

tenascin-W in brain tumors has not been investigated. We analyzed protein levels of tenascin-W in 38 human gliomas (29 glioblastomas, 5 astrocytomas, and 4 oligodendromas) and found expression of tenascin-W in more than 80% of all tumor samples, whereas no tenascin-W could be detected in control brain tissues. Immunohistochemical co-stainings of tenascin-W and von Willebrand factor revealed that tenascin-W is localized around

blood vessels exclusively in tumor samples. To assess if tenascin-W influences the behavior of endothelial cells in vitro, Human Umbilical Vein Endothelial Cells (HUVEC) were seeded on a collagen substratum including tenascin-W. The presence of tenascin-W increased the proportion of elongated cells and augmented click here the mean speed of migration of the cell population. Furthermore, STK38 tenascin-W triggered sprouting of HUVEC spheroids to a similar extent as the pro-angiogenic factor tenascin-C. Our study thus identifies tenascin-W as a find more candidate biomarker for brain tumor angiogenesis that could be used as molecular target for therapy irrespective of the glioma subtype. O26 Protease activated receptor1, PAR1 Acts via a Novel G a13 -DVL Axis to Stabilize b-catenin Levels

Hagit Turm 1 , Myriam Maoz1, Stefan Offermanns2, Rachel Bar-Shavit1 1 Oncology, Hadassah- Hebrew University Hospital, Jerusalem, Israel, 2 Institute of Pharmacology, University of Heidelberg, Heidelberg, Germany We have previously shown a novel link between human protease-activated-receptor1 (hPar1) and b-catenin stabilization. The over-expression of hPar1 leads to a striking stabilization of b-catenin, a well established core process of the Wnt signaling pathway. Here we elucidate the mechanism linking PAR1 to b-catenin oncogenicity. PAR1 is selectively associated with activated Ga13, recruiting next dishevelled (DVL), an upstream Wnt signaling protein. Using constructs exhibiting either individually distinct DVL domains (e.g., DIX, PDZ and DEP) or depleted DVL sites or a GST-DVL-DIX column, we showed that the DIX domain associates with Ga13.