Our selectin-binding site studies furthermore indicate that the glycotope expression, and thus the metastatic potential of tumour cells, is subject to a dynamic process similar to the other phenotypical changes observed during the EMT of tumour cells. Acknowledgments We thank Susanne Feldhaus for her excellent technical help, Roswitha Reusch for the skilful handling of the animals, and Dr Nina Nehmann for the Alu-Primer sequences. metastases in the E- and P-selectin-deficient scid mice grew within the pulmonary artery and not in the alveolar septae as they did in wild-type scid mice. Flow experiments indicate that tumour cells roll and tether on an E- and P-selectin matrix similar to leukocytes; however, firm adhesion is mainly mediated in E-selectin. Conclusion: Our results indicate that E- and P-selectins have a crucial role in spontaneous metastasis formation. As the human HT 29 colon cancer cells are positive for the lectin (HPA), which identified the metastatic phenotype in earlier clinical studies, these results are of particular clinical relevance. (HPA), has been particularly useful, binding preferentially to tumour cells of those patients with a poor prognosis caused by a wide metastatic spread of their primary tumours (Mitchell and Schumacher, 1999; Brooks, 2000; Konno also holds true in a xenograft animal model of human breast and colon cancer LY 254155 metastasis. In general, only those human breast and colon cancer cell lines metastasised in severe combined immunodeficient (scid) mice that were HPA positive (Schumacher and Adam, 1997). For LY 254155 further analysis of the metastatic process, we focused in this study on the metastatic and HPA-positive human colon carcinoma cell line, HT 29. The reason why HPA binding to tumour cells is associated with their metastatic potential has remained unclear RN so far. HPA-binding sites are located at the tumour cell surface (Mitchell stimulates the expression of the endothelial (E) and platelet (P) selectins on the luminal surface of endothelial cells (Rajan cell flow assay was performed simulating the physiologic shear stresses in post-capillary venules. This experiment revealed that HT 29 cells firmly adhered and rolled on E-selectin fusion protein-coated capillaries with a low concentration of 5?grown HT 29 tumours in both mouse strains, whereas it was only weakly present on the tumour cells of HT 29 cells grown in cell culture and in the metastatic deposits (Figure 6). These findings suggest that the major selectin ligand present on HT 29 cells is sLea. However, preincubation with anti-sLea did not block following staining with E- or P-selectin IgG fusion protein, thus indicating the presence of diverse selectin-binding structures on HT 29 cells. sLex is a tetrasaccharide built on galactose, (2004), LY 254155 who showed that oxygenation influences selectin-binding site expression. This difference in expression pattern is explained by the observation that transformational effects, such as growth to high cell densities, 2D 3D hypoxia or development, lead to a modification of carbohydrate patterns between tumour cells expanded and (Warren em et al /em , 1978). Therefore, binding design and metastatic potential of tumour cells as indicated by selectin and HPA-binding site appearance aren’t static features, but could be put through a dynamic procedure as observed through the epithelial mesenchymal changeover (EMT) of tumour cells. Through the EMT, the tumour cells eliminate their connection with their neighbouring epithelial cells and basal lamina, respectively, and find a migratory (=mesenchymal) phenotype (Berx em et al /em , 2007). Acquiring this thought additional, it could also suggest that the capability to metastasise reaches least partly at the mercy of regulatory mechanisms. In conclusion, in this research the considerable decrease in the amount of spontaneous lung metastases from the individual cancer of the colon cell series HT 29 in E- and P-selectin-deficient scid mice could possibly be quantified em in vivo /em . This selecting LY 254155 highlights the need for the selectins for metastasis development. Our selectin-binding site research suggest which the glycotope appearance furthermore, and therefore the metastatic potential of tumour cells, is normally at the mercy of a dynamic procedure like the various other phenotypical changes noticed through the EMT of tumour cells. Acknowledgments We give thanks to Susanne Feldhaus on her behalf excellent specialized help, Roswitha Reusch for the skilful managing of the pets, and Dr Nina Nehmann for the Alu-Primer sequences. The ongoing function in the authors laboratory was funded with the Mildred Scheel Base, the Deutsche Forschungsgemeinschaft as well as the Wilhem Sander Stiftung. UR received a scholarship or grant in the Werner Otto Base..