A Genetic Strategy for Graded and Dynamic Control of Cell-Matrix Mechanobiology

Mechanical interactions between cells and the surrounding extracellular matrix, such as adhesion, contraction, and force transduction, play a central role in many fundamental cell behaviors, including proliferation, cell death, and motility. The ability to precisely manipulate the intracellular machinery that regulates these interactions could therefore provide a powerful tool for controlling the mechanical properties of living cells and could also allow us to re-engineer how cells sense and respond to mechanical stimuli in their microenvironment, which would be particularly useful for tissue engineering and cellular technologies where cells are interfaced with synthetic microenvironments. Towards this goal, we have genetically engineered stable cell lines in which we can precisely and dynamically alter the mechanobiological behavior of living cells by varying the activity of signal transduction proteins, such as RhoA GTPase, using constitutively active and dominant negative mutants under the control of a tetracycline-repressible promoter. Through a variety of imaging and biophysical techniques, including atomic force microscopy and traction force microscopy, we have demonstrated graded and dynamic control over cytoskeletal architecture, cell shape and spreading, contractility, and cellular stiffness. In addition, using glioblastoma multiforme as a model system, we show how these cell lines can be used to study the effects of altered cellular mechanical properties on cancer cell motility and invasion.