The extravasation of cancer cells is a key step of the metastatic cascade. Polymorphisms in genes encoding adhesion molecules can facilitate metastasis by increasing the strength of interaction between tumor and endothelial cells as well as impacting other properties of cancer cells. We investigated the Ser128Arg (a561c at the nucleotide level) polymorphism in the E-selectin gene in patients with metastatic colon cancer and its functional significance. Genotyping for a561c polymorphism was performed on 172 cancer patients and on an age-matched control population. The colon cancer group was divided into groups with (M 1 ) and without observable metastasis (M 2 ). For in vitro functional assays, Huvec transfected cells expressing wild-type (WT) or the S128R variant of E-selectin were established to study in vitro binding ability and signal transduction processes of T84 colon cancer cell line. Our results demonstrated that the Arginine 128 allele was more prevalent in the M 1 group than in the M 2 group or normal controls (p < 0.005; odds ratio, 1.56; 95% confidence interval (CI) 1.16-1.92; p < 0.001, odds ratio 5 1.65; CI 5 1.24-1.99, respectively). In vitro, S128R E-selectin transfected Huvec cells, supported increased adhesion as well as increased cellular signaling of T84 cancer cells compared to WT E-selectin and mock-transfected Huvec cells. These findings suggest that the E-selectin S128R polymorphism can functionally affect tumor-endothelial interactions as well as motility and signaling properties of neoplastic cells that may modulate the metastatic phenotype. ' 2007 Wiley-Liss, Inc.Key words: E-selectin; colon cancer; genetic polymorphisms; metastasis; cell signaling Metastasis is the main cause of death for cancer patients. Metastatic dissemination is a complex process, depending on the ability of malignant cells to escape from the primary tumor, penetrate and flow through the bloodstream, adhere to the vascular bed and then invade and proliferate in the organ parenchyma.1 Interactions of blood-borne carcinoma cells and the microvasculature are essential prerequisites for metastasis to occur. These processes involve mechanical contact and transient attachment, which are mediated by endothelial surface adhesion molecules and their ligands on the neoplastic cells.2 Factors mediating these interactions are therefore viewed as important determinants of the metastatic phenotype. Among the molecules mediating tumor-endothelium interactions are selectins. [3][4][5][6][7] The selectins are a small family of intercellular adhesion molecules with 3 members: E-, P-and Lselectin. They share a mosaic structure consisting of an amino-terminal domain followed by an epidermal growth factor (EGF)-like domain, a variable number of complement regulatory repeats, a transmembrane domain and a short cytoplasmic domain. E-selectin (ELAM-1) is expressed by endothelial cells, which are activated by cytokines released during the inflammatory process and plays an important role in neutrophil extravasation into injured tissues as w...

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To better understand the relationship between tumor heterogeneity, differentiation, and metastasis, suitable experimental models permitting in vitro and in vivo studies are necessary. A new variant cell line (T84SF) exhibiting an altered phenotype was recently selected from a colon cancer cell line (T84) by repetitive plating on TNF-α treated human endothelial cells and subsequent selection for adherent cells. The matched pair of cell lines provides a useful system to investigate the extravasation step of the metastatic cascade. Since analysis of morphological differences can be instructive to the understanding of metastatic potential of tumor cells, we compared the ultrastructural and functional phenotype of T84 and T84SF cells in vitro and in vivo. The reported ultrastructural features evidence differences between the two cell lines; selected cells showed a marked pleomorphism of cell size and nuclei, shape, and greater surface complexity. These morphological differences were also coupled with biochemical data showing a distinct tyrosine phosphorylation-based signaling, an altered localization of β-catenin, MAPK, and AKT activation, as well as an increased expression in T84SF cells of Bcl-X L , a major regulator of apoptosis. Therefore, these cell lines represent a step forward in the development of appropriate models in vitro and in vivo to investigate colon cancer progression.

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