Deficiency in surface expression of E‐selectin ligand promotes lung colonization in a mouse model of breast cancer

Abstract

Expression of sialyl Lewis x (sLe x ) and sLe a on tumor cells is thought to facilitate metastasis by promoting cell adhesion to selectins on vascular endothelial cells. Experiments supporting this concept usually bypass the early steps of the metastatic process by employing tumor cells that are injected directly into the blood. We investigated the relative role of sLe x oligosaccharide in the dissemination of breast carcinoma, employing a spontaneous murine metastasis model. An sLe x deficient subpopulation of the 4T1 mammary carcinoma cell line was produced by negative selection using the sLe x -reactive KM93 MAb. This subpopulation was negative for E-selectin binding but retained P-selectin binding. Both sLe x -negative and -positive cells grew at the same rate; however, sLe x -negative cells spread more efficiently on plates and had greater motility in wound-scratch assays. Mice inoculated in the mammary fat pad with sLe x -negative and -positive variants produced lung metastases. However, the number of lung metastases was significantly increased in the group inoculated with the sLe x -negative variant (p 5 0.0031), indicating that negative selection for the sLe x epitope resulted in enrichment for a subpopulation of cells with a high metastatic phenotype. Cell variants demonstrated significant differences in cellular morphology and pattern of tumor growth in primary and secondary tumor sites. These results strongly suggest that loss of sLe x may facilitate the metastatic process by contributing to escape from the primary tumor mass. ' 2005 Wiley-Liss, Inc.Key words: sialyl Lewis x antigen; metastasis; 4T1 cells; breast cancer Tumor metastasis is a multistep process requiring detachment of malignant cells from the primary tumor, penetration of blood or lymph vessels, attachment to endothelium of distant organs and formation of new tumor foci. 1,2 Tissue invasion and metastasis of tumor cells are highly dependent on cell-cell interactions, many of which involve alterations in cell surface glycosylation patterns. 3,4 Although adhesion pathways utilized by tumor cells show considerable diversity, members of the selectin family of molecules and numerous neolactoseries antigens highly expressed on the tumor cell surface are involved in tumor metastasis by mediating binding of blood-borne tumor cells via E-and/or P-selectin to vascular endothelium. [5][6][7][8][9][10] Much of what we know about selectin interactions comes from studies of leukocytes. 11,12 Functionally, the binding of selectins to leukocytes requires sialylated and fucosylated carbohydrate structures; their prototypes are SAa2-3Galb1-4(Fuca1-3)GlcNAc and SAa2-3Galb1-3(Fuca1-4)GlcNAc, referred to as sLe x and sLe a , respectively. [13][14][15] Both sLe x and sLe a are involved in selectin-mediated adhesion of cancer cells to vascular endothelium, and these determinants are thought to be closely associated with hematogenous metastasis of cancers. [16][17][18][19] These determinants not only are markers for cancer but also are functionally implicated ...

Chondroitin sulfates play a major role in breast cancer metastasis: a role for CSPG4 and CHST11gene expression in forming surface P-selectin ligands in aggressive breast cancer cells

“…We have shown glycan interactions with P-selectin and the significance of P-selectin binding in metastasis of a murine mammary cell line [24,52]. Our previous findings support the concept that CS chains promote survival in the circulation and tumor cell extravasation via P-selectin-mediated binding to platelets and endothelial cells.…”

“…Each mouse (10 mice per group) received 2 × 10 4 4T1 cells. Mice were sacrificed 25 days after tumor cell injection and lungs were harvested to determine clonogenic cells by growing cells in medium containing 6-thioguanine [52]. Animal studies have been reviewed and approved by the Institutional Care and Use Committee of UAMS.…”

Fructose as a carbon source induces an aggressive phenotype in MDA-MB-468 breast tumor cells

“…Variations in oligosaccharide structures contribute to folding, stability, and biologic function of glycoproteins (33). The importance of specific glycosylation events in mammary cancer metastases has been clearly demonstrated in transgenic mice (2).…”

Primary 4T1 tumor resection provides critical “window of opportunity” for immunotherapy

“…Mice were sacrificed at 2, 4, 6, 13, 17–20, 30–33 days after surgery. The number of clonogenic tumor cells in the lungs was analyzed as described [17,30]. Briefly, the lungs were harvested in aseptic conditions, digested with collagenase type IV (1mg/ml in 1× HBSS) (Sigma-Aldrich, St. Louis, MO) at 4°C for 75min.…”