Mechanical Properties of Normal Breast Cells and Metastatic Cancer Cells in Co-Culture

Abstract

The mechanical properties of cells play an important role in cellular processes such as cell migration, division, and mechanotransduction. Stiffness is an important mechanical property and can be measured using an atomic force microscope (AFM) (to determine the Young's modulus). Our previous studies showed that normal breast cells (human mammary epithelial cells, HMEC) are stiffer than highly metastatic breast cancer cells (MDA-MB-231). Also, normal breast cells in the center of a monolayer micro-colony are stiffer than cells on the periphery and isolated cells which means that the microenvironment significantly affects the mechanical properties of cells. However, the effect on stiffness when normal cells and cancer cells grow together has not been well established. In this study, we investigate how the mechanical properties of HMEC and MDA-MB-231 cells change in co-culture. Our preliminary results show that both HMEC and MDA-MB-231 cells get significantly stiffer in co-culture (HMEC 1.3 kPa -> 15 kPa; MDA-MB-231 0.59 kPa -> 1.48 kPa). This study will offer an understanding of normal-to-cancer cell interactions affect stiffness, and consequently how it might be correlated to metastasis.