title: CD44 variant isoforms expressed by breast cancer cells are functional E-selectin ligands under flow conditions.
abstract: Adhesion of circulating tumor cells to vascular endothelium is mediated by specialized molecules that are functional under shear forces exerted by hematogenous flow. Endothelial E-selectin binding to glycoforms of CD44 mediates shear-resistant cell adhesion in numerous physiological and pathological conditions. However, this pathway is poorly understood in breast cancer and is the focus of the present investigation. All breast cancer cell lines used in this study strongly expressed CD44. In particular, BT-20 cells expressed CD44s and multiple CD44v isoforms, whereas MDA-MB-231 cells predominantly expressed CD44s but weakly expressed CD44v isoforms. CD44 expressed by BT-20, but not MDA-MB-231, cells possessed E-selectin ligand activity as detected by Western blotting and antigen capture assays. Importantly, CD44 expressed by intact BT-20 cells were functional E-selectin ligands, regulating cell rolling and adhesion under physiological flow conditions, as found by shRNA-targeted silencing of CD44. Antigen capture assays strongly suggest greater shear-resistant E-selectin ligand activity of BT-20 cell CD44v isoforms than CD44s. Surprisingly, CD44 was not recognized by the HECA-452 MAb, which detects sialofucosylated epitopes traditionally expressed by selectin ligands, suggesting that BT-20 cells express a novel glycoform of CD44v as an E-selectin ligand. The activity of this glycoform was predominantly attributed to N-linked glycans. Furthermore, expression of CD44v as an E-selectin ligand correlated with high levels of fucosyltransferase-3 and -6 and epithelial, rather than mesenchymal, cell phenotype. Together, these data demonstrate that expression of CD44 as a functional E-selectin ligand may be important in breast cancer metastasis.
authors.affiliation: Department of Chemical and Biomolecular Engineering, Russ College of Engineering and Technology, Ohio University, Athens, Ohio;
authors.forename: Venktesh S
authors.initials: VS
authors.lastname: Shirure
authors.affiliation: Department of Chemical and Biomolecular Engineering, Russ College of Engineering and Technology, Ohio University, Athens, Ohio;
authors.forename: Tiantian
authors.initials: T
authors.lastname: Liu
authors.affiliation: Department of Chemical and Biomolecular Engineering, Russ College of Engineering and Technology, Ohio University, Athens, Ohio;
authors.forename: Luis F
authors.initials: LF
authors.lastname: Delgadillo
authors.affiliation: Department of Chemical and Biomolecular Engineering, Russ College of Engineering and Technology, Ohio University, Athens, Ohio;
authors.forename: Chaz M
authors.initials: CM
authors.lastname: Cuckler
authors.affiliation: Biomedical Engineering Program, Russ College of Engineering and Technology, Ohio University, Athens, Ohio; Department of Physics and Astronomy, College of Arts and Sciences, Ohio University, Athens, Ohio; and.
authors.forename: David F J
authors.initials: DF
authors.lastname: Tees
authors.affiliation: Biomedical Engineering Program, Russ College of Engineering and Technology, Ohio University, Athens, Ohio; Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, Ohio University, Athens, Ohio.
authors.forename: Fabian
authors.initials: F
authors.lastname: Benencia
authors.affiliation: Department of Chemical and Biomolecular Engineering, Russ College of Engineering and Technology, Ohio University, Athens, Ohio; Biomedical Engineering Program, Russ College of Engineering and Technology, Ohio University, Athens, Ohio;
authors.forename: Douglas J
authors.initials: DJ
authors.lastname: Goetz
authors.affiliation: Department of Chemical and Biomolecular Engineering, Russ College of Engineering and Technology, Ohio University, Athens, Ohio; Biomedical Engineering Program, Russ College of Engineering and Technology, Ohio University, Athens, Ohio; burdick@ohio.edu.
authors.forename: Monica M
authors.initials: MM
authors.lastname: Burdick
mesh_terms: D000818:Animals; D001943:Breast Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D016466:CHO Cells; D002448:Cell Adhesion; D045744:Cell Line, Tumor; D002465:Cell Movement; D003412:Cricetulus; D019040:E-Selectin / Q000235:genetics / Q000378:metabolism*; D042783:Endothelial Cells / Q000378:metabolism; D058750:Epithelial-Mesenchymal Transition; D005260:Female; D005647:Fucosyltransferases / Q000378:metabolism; D006031:Glycosylation; D006801:Humans; D018960:Hyaluronan Receptors / Q000235:genetics / Q000378:metabolism*; D008024:Ligands; D009362:Neoplasm Metastasis; D010641:Phenotype; D020033:Protein Isoforms; D034622:RNA Interference; D012039:Regional Blood Flow; D014162:Transfection
chemical_list: C497483:CD44 protein, human; D019040:E-Selectin; D018960:Hyaluronan Receptors; D008024:Ligands; D020033:Protein Isoforms; D005647:Fucosyltransferases; C019818:3-galactosyl-N-acetylglucosaminide 4-alpha-L-fucosyltransferase; C515956:FUT6 protein, human
keywords: CD44; E-selectin; cell adhesion; epithelial-to-mesenchymal transition; metastasis