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Seminars and Colloquia


Mechanobiology of Cell-Substrate Interactions 
Mon, Apr 09, 2018,   12:00 PM to 01:00 PM at Seminar Room 34, 2nd Floor, Main Building

Dr. Namrata Gundiah
Indian Institute of Science, Bangalore

An organized and crosslinked extracellular matrix in tissues primarily contributes to its microstructure and material properties; these are also essential in determining organismal form, function, and homeostasis. A higher extracellular matrix stiffness alters the cellular adhesion, cytoskeletal dynamics, and receptor signaling. TGF-β is a highly expressed cytokine which acts as a tumor suppressor in normal conditions but as a promoter in cancers to contribute to epithelial to mesenchymal transitions. The biochemical signaling pathways associated with TGF-β have been well characterized but its correlation with cell mechanics is under explored. We hypothesized that in breast cancers, exposure to active TGF-β leads to increased cellular deformability that facilitates transport through narrow spaces. We also hypothesized that TGF-β treatment promotes increased cellular traction forces. We indented breast cancer cells with differential invasiveness (MCF-7 and MDA-MB-231) using an atomic force microscope (AFM) to quantify the cellular stiffness using a modified Hertzian model with thickness correction. We also performed stress relaxation experiments to characterize the viscoelastic properties of the cells after TGF-β treatment. Our results show a temporal context dependent influence of TGF-β on the cell mechanical properties that correlated with the invasive potential of cells. Confocal imaging showed increased actin fiber expression due to TGF-β treatment that suggest differential microstructural organization of the cytoskleleton. Current investigations are aimed at linking cell traction forces on cells treated with TGF-β, quantified using a regularized Fourier Transform Traction Cytometry, on a range of substrate stiffness. Such studies provide valuable insights into the mechanobiology of cell- substrate interactions that are important in cancer metastasis.