Profiling changes in the metastatic potential of breast cancer cells exposed to flow

Abstract

Most cancer related deaths can be directly attributed to blood bourne metastasis.Metastasis is the process by which tumor cells leave the initial tumor travel through thecirculatory or lymphatic system to distant sites where secondary tumors are formed.One important part of metastasis is epithelial to mesenchymal transition (EMT), inwhich cells lose their epithelial cell morphology and gain a mesenchymal morphology.This transition causes enhanced migratory capacity, invasiveness, and resistance tocell death, creating a more metastatic cell. In this study we used a parallel plate flowchamber to create conditions that would encourage EMT in breast cancer cells. Severalbreast cancer cell lines were exposed to high shear stress (10 dyn/cm2) for 20 hours.RNA was collected from static and flow exposed cells. RT-qPCR was used to comparethe expression of four genes known to be related to EMT or cell invasiveness. Wefound that TSP-1 gene expression was strongly upregulated, MMP-14 was slightlyupregulated, ICAM-1 was slightly downregulated, and TGFR1 gene expression didnot change. TSP-1 has been shown to increase tumor cell migration and invasivenessand MMP-14 has also been associated with increased tumor cell invasiveness. ICAM-1is an intercellular adhesion molecule that plays different roles in cell to cell adhesion.The loss of ICAM-1 and the up regulation of TSP-1 and MMP-14 show that the cellsexposed to flow lose some intercellular interaction and gain increased mobility andinvasiveness, all of which is indicative of EMT. These results show for the first timethat fluid forces can upregulate genes involved in cancer cell EMT. This will be used infuture studies to investigate more about the metastatic potential of breast cancer cells.11