Analysis of traction forces exerted by normal and tumor cells

GONZALO GIORDANO; E. A. REBECA PALACIOS; LIA I PIETRASANTA; LORENA SIGAUT

Córdoba

Congreso; LI Reunión Anual de la Sociedad Argentina de Biofísica; 2023

Sociedad Argentina de Biofísica

Cells actively sense their environment by exerting traction forces on the substrate to which they adhere or migrate [1], through specialized structures called focal adhesions, which physically link components of the cytoskeleton with the extracellular matrix. These traction forces are crucial for cell adhesion, mechanotransduction, and cell migration; and they play a crucial role in many biological processes, such as embryogenesis or metastasis. In this work, we propose to analyze the traction forces generated by normal and tumor-derived human mammary epithelial cells, cultivated on substrates with controlled mechanical properties and different biochemical conditions, by traction force microscopy [2,3]. To achieve this aim, we manufactured deformable substrates with fluorescent nanospheres embedded in them, on which cells are cultured. The substrate deformation due to cellular traction is quantified by tracking the localization of the nanospheres using confocal microscopy. A PIV-based algorithm was written and optimized to obtain the magnitude and direction of the deformation produce by the cell, processing the fluorescence images of the cell-deformed substrate compared to the relaxed substrate. As an experimental model, tumor and normal epithelial cells derived from human mammary gland, MCF7 and MCF10 respectively, are used. To evaluate the cellular response in the generation of traction forces when varying the serum content, experiments were carried out at different serum percentage. For both cell lines, the deformation maps are quantified and analyzed to detect potential differences related to the normal and tumor state of the cells under study. Preliminary results show that in the presence of serum, both cell lines produce similar average substrate deformation due to traction forces. However, the deformation produced by MCF10 cells does not change with serum content, while in the absence of serum, MCF7 cell-induced substrate deformation is significantly decreased, indicating a decrease in traction force generation.References[1] Geiger B, Spatz JP, Bershadsky AD. (2009) Rev Mol Cell Bio.10(1):21–33.[2] Dembo M, Oliver T, Ishihara A, Jacobson K. (1996) Biophys. J. 70(4): 2008-2022.[3] Sigaut L, Bianchi M, von Bilderling C, Pietrasanta LI (2021) PLoS ONE 16(5): e0251411.Acknowledgments: This work is funded by CONICET, UBA, ANPCyT.