Administration of IL-8 to three prostate cancer cell lines (LNCaP, PC3 and/or 22RV1 cells) and two bone marrow stromal cell lines (HS5 and HS27A) increases AP-1 and NF-κB-directed gene transcription, leading to increased expression of cathepsin K and the potent, cell-tethered collagenase, MT1-MMP, enzymes known to be implicit in promoting bone turnover. Furthermore, our studies demonstrate that IL-8 signalling promotes nuclear translocation of the transcriptional co-activator, β-catenin, underpinning increases

in the LY2603618 expression of a downstream gene target of TCF/LEF transcripiton complex, the serine protease uPA. RNAi-mediated attenuation of β-catenin expression attenuated this IL-8 induced increase in uPA expression. Current studies are characterizing the importance of IL-8-induced protease activity within the bone microenvironment, initiating bone remodelling and promoting activation of matrix-associated growth factors to underpin the osteoclastogenic and osteoblastic phases of bone metastasis in prostate cancer. O119 MMP-14 (MT1-MMP) Mediated Endoglin Shedding Regulates Tumour Angiogenesis Lukas Hawinkels 1,2 , Patty Kuiper2, Hein Verspaget2, Eliza Wiercinska1, Roeland Romidepsin cell line Hanemaaijer4, Peter ten Dijke1, Cornelis Sier2,3 1 Department of Molecular Cell Biology and Centre for Biomedical Genetics, Leiden University Medical Centre, Leiden, the

Netherlands, 2 Department of Gastroenterology-Hepatology, Leiden University Medical Centre, Leiden, the Netherlands, 3 Department of Surgery, Leiden University Medical Centre, Leiden, the Netherlands, 4 TNO, Quality of Life BioSciences, Leiden, the Netherlands Endoglin is a TGFβ coreceptor

and is highly expressed on angiogenic endothelial cells with a crucial role in angiogenesis. A soluble form of endoglin is present in the circulation, which might possess anti-angiogenic properties. Increased soluble endoglin levels are reported in pregnant women suffering from pre-eclampsia, but reports on soluble endoglin in cancer patients are contradictory. We examined soluble endoglin levels in colorectal cancer in association with the endoglin shedding mechanism. Immunohistochemical Meloxicam analysis of colorectal cancer specimens revealed high endoglin expression in angiogenic endothelial cells. Interestingly, low endoglin expression on the tumour vessels was accompanied by high MMP14 expression, the most this website abundantly expressed membrane-type MMP. In the circulation of 23 patients soluble endoglin levels were slightly decreased compared to healthy controls. The mechanism of endoglin shedding was evaluated in vitro using HUVEC endothelial cells, which secrete high levels of endoglin. The release of endoglin was inhibited by addition of broad-spectrum MMP inhibitors, but not by adding specific serine- or cystein-protease inhibitors.