Direct Measurements on CD24-Mediated Rolling of Human Breast Cancer MCF-7 Cells on E-Selectin

Abstract

Tumor cell rolling on the endothelium plays a key role in the initial steps of cancer metastasis, i.e. extravasation of circulating tumor cells (CTCs). Identification of the ligands that induce the rolling of cells is thus critical to understand how cancers metastasize. We have previously demonstrated that MCF-7 cells, human breast cancer cells, exhibit the rolling response selectively on E-selectinimmobilized surfaces. However, the ligand that induces rolling of MCF-7 cells on E-selectin has not yet been identified, as these cells lack commonly known E-selectin ligands. Here we report, for the first time to our knowledge, a set of quantitative and direct evidence demonstrating that CD24 expressed on MCF-7 cell membranes is responsible for rolling of the cells on E-selectin. The binding kinetics between CD24 and E-selectin was directly measured using surface plasmon resonance (SPR), which revealed that CD24 has a binding affinity against E-selectin (K D = 3.4 ± 0.7 nM). The involvement of CD24 in MCF-7 cell rolling was confirmed by the rolling behavior that was completely blocked when cells were treated with anti-CD24. A simulated study by flowing microspheres coated with CD24 onto E-selectin-immobilized surfaces further revealed that the binding is Ca 2+ dependent. Additionally, we have found that actin filaments are involved in the CD24-mediated cell rolling, as observed by the decreased rolling velocities of the MCF-7 cells upon treatment with cytochalasin D (an inhibitor of actin-filament dynamics) and the stationary binding of CD24-coated microspheres (the lack of actins) on the E-selectin-immobilized slides. Given that CD24 is known to be directly related to enhanced invasiveness of cancer cells, our results imply that CD24-based cell rolling on E-selectin mediates, at least partially, cancer cell extravasation, resulting in metastasis.

Immobilized surfactant-nanotube complexes support selectin-mediated capture of viable circulating tumor cells in the absence of capture antibodies

“…Here, the effect of immobilized surfactant-nanotube complexes on ES-mediated adhesion of tumor cells under flow was assessed. Sialylated carbohydrate ligands are expressed on the surface of many tumor cell types, which can induce rolling tumor cell adhesion on ES (47),(48) . We initially studied COLO 205 colon cancer cell and MCF7 breast cancer cell adhesion to ES on immobilized surfactant-nanotube surfaces, given that they have been shown to interact with ES under physiologically-relevant shear stresses (47),(49),(50) .…”

Glycomechanics of the Metastatic Cascade: Tumor Cell–Endothelial Cell Interactions in the Circulation

“…Using the parallel flow chamber assay, they confirmed the physiological role of CD24 as a ligand for P-selectin on KS cells in the presence of shear stress. 2 Later, Myung et al 115 reported the role of CD24 on MCF7 breast cancer cells as a ligand for E-selectin under flow by measuring the binding kinetics of CD24 with E-selectin with surface plasmon resonance (SPR). The identification of CD24 as a ligand for both P-and E-selectin may provide better understanding of the adhesion and invasion mechanisms of metastatic breast cancer.…”

CD133 and CD24 expression in renal tissue of patients affected by autosomal dominant polcystic kidney disease

“…CD133 function is not clear but its presence on early and undifferentiated cells is suggestive of a growth factor receptor, and the presence of five tyrosine residues on the 50-aa cytoplasmic tail may indicate that the protein is phosphorylated in response to ligand binding and triggers a signal transduction [11]. CD24 is a sialoglycoprotein expressed on mature granulocytes [12], B and T lymphocyte subsets [13,14], normal and cancer stem cells [15,16]. The protein is anchored via a glycosyl phosphatidylinositol to cell surface.…”