Drug-induced changes of cytoskeletal structure and mechanics in fibroblasts: An atomic force microscopy study

The effect of various drugs affecting the integrity of different components of the cytoskeleton on the elasticity of two fibroblast cell lines was inv estigated by elasticity measurements with an atomic force microscope (AFM). Disaggregation of actin filaments always resulted in a distinct decrease i n the cell's average elastic modulus indicating the crucial importance of t he actin network for the mechanical stability of living cells. Disruption o r chemical stabilization of microtubules did not affect cell elasticity. Fo r the f-actin-disrupting drugs different mechanisms of drug action were obs erved. Cytochalasins B and D and Latrunculin A disassembled stress fibers. For Cytochalasin D this was accompanied by an aggregation of actin within t he cytosol. Jasplakinolide disaggregated actin filaments but did not disass emble stress fibers. Fibrous structures found in AFM images and elasticity maps of fibroblasts could be identified as stress fibers by correlation of AFM data and fluorescence images.