title: Inhibition of actin dynamics during epithelial-to-mesenchymal transition.
abstract: Transforming growth factor β1 is one of the main inducers of epithelial-to-mesenchymal transition (EMT). During EMT cells from an ordered epithelial state adopt a fibroblast-like shape combined with a reorganization of the cytoskeleton and altered cell-cell and cell-substrate interactions. Interestingly, an increased cellular motion lasting up to 9h after cytokine stimulation takes place. These changes in cellular shape and dynamics can be monitored by impedance spectroscopy. Analyzing impedance noise by means of variance and detrended fluctuation analysis provides information about the magnitude of vertical cellular micromotility and the long-term correlation of the impedance signal. Via preincubation with Rho kinase inhibitor Y-27632, blebbistatin, and the protein inhibitors rapamycin and cycloheximide before cytokine addition, we were able to assign the origin of the dynamic changes. Fluctuations upon TGF-β1 administration were diminished using cycloheximide, blebbistatin and rapamycin. Consequently, we conclude that mainly actin contractility and de novo protein synthesis leading to changes in actin polymerization/depolymerization processes are responsible for the detected alterations, whereas activation of Rho kinases (ROCK) is not involved. Importantly, none of the used agents affected the EMT phenotype, reflected in unchanged static impedance parameters, optical micrographs and unmodified correlations displayed in the impedance noise.
authors.affiliation: Institute of Physical Chemistry, Georg-August-University, Tammannstrasse 6, 37077 Göttingen, Germany.
authors.forename: David
authors.initials: D
authors.lastname: Schneider
authors.forename: Andreas
authors.initials: A
authors.lastname: Janshoff
mesh_terms: D000199:Actins / Q000037:antagonists & inhibitors / Q000378:metabolism*; D000577:Amides / Q000494:pharmacology; D000818:Animals; D002460:Cell Line; D048430:Cell Shape; D058266:Dielectric Spectroscopy; D058750:Epithelial-Mesenchymal Transition / Q000187:drug effects / Q000502:physiology*; D006576:Heterocyclic Compounds, 4 or More Rings / Q000494:pharmacology; D051379:Mice; D008856:Microscopy, Fluorescence; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D011725:Pyridines / Q000494:pharmacology; D016212:Transforming Growth Factor beta / Q000378:metabolism / Q000494:pharmacology; D054460:rho-Associated Kinases / Q000037:antagonists & inhibitors
chemical_list: D000199:Actins; D000577:Amides; D006576:Heterocyclic Compounds, 4 or More Rings; D047428:Protein Kinase Inhibitors; D011725:Pyridines; D016212:Transforming Growth Factor beta; C108830:Y 27632; C472645:blebbistatin; D054460:rho-Associated Kinases