Abstract 866: The epithelial-to-mesenchymal transition regulates E-selectin ligand activities of breast cancer cells

Abstract

Abstract The epithelial-to-mesenchymal transition (EMT) leads to specific stem-like and invasive properties in breast cancer cells. However, it remains unclear whether the EMT modifies sialofucosylated ligands that circulating tumor cells use to attach and adhere to vascular endothelial E-selectin during metastasis. To address this issue, immunohistochemistry and E-selectin microsphere dynamic adhesion assays were initially used to assay 110 cases of breast cancer for EMT biomarkers and E-selectin ligand activity. The expression of E-cadherin, but not N-cadherin or vimentin, directly correlated with E-selectin ligand activity. Thus, it was hypothesized that the EMT, and in turn the mesenchymal-to-epithelial transition (MET), regulate expression of functional E-selectin ligands in breast cancer cells. The ectopic expression or shRNA knockdown of transcription factors (i.e., Snail and Twist) in target cell lines were used to induce EMT or MET, respectively. Shear flow adhesion assays and flow cytometry demonstrated that cells with epithelial phenotypes had greater E-selectin ligand activities and greater expression of sialofucosylated carbohydrates compared to cells with mesenchymal phenotypes. Moreover, glycoprotein E-selectin ligand activities of breast cancer cells were more affected by the EMT compared to glycolipid E-selectin ligand activities. Assessing expression of α1,3- and α1,4- fucosyltransferases (FUT) at the RNA level using qRT-PCR revealed that FUT3 and FUT6 gene expression were decreased via the EMT, corresponding to the lowered E-selectin ligand activities observed in mesenchymal phenotype cells. Altogether, the results of this investigation demonstrate that the EMT, as well as the MET, mechanistically regulate the expression of functional E-selectin ligands expressed by breast cancer cells. Citation Format: Grady E. Carlson, Alexander O. Ostermann, Venktesh S. Shirure, Fabian Benencia, Monica M. Burdick. The epithelial-to-mesenchymal transition regulates E-selectin ligand activities of breast cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 866. doi:10.1158/1538-7445.AM2017-866