title: Antiepileptic teratogen valproic acid (VPA) modulates organisation and dynamics of the actin cytoskeleton.
abstract: The antiepileptic drug valproic acid (VPA) and teratogenic VPA analogues have been demonstrated to inhibit cell motility and affect cell morphology. We here show that disruption of microtubules or of microfilaments by exposure to nocodazole or cytochalasin D had different effects on morphology of control cells and cells treated with VPA, indicating that VPA affected the cytoskeletal determinants of cell morphology. Furthermore, VPA treatment induced an increase of F-actin, and of FAK, paxillin, vinculin, and phosphotyrosine in focal adhesion complexes. These changes were accompanied by increased adhesion of VPA-treated cells to the extracellular matrix. Treatment with an RGD-containing peptide reducing integrin binding to components of the extracellular matrix partially reverted the motility inhibition induced by VPA, indicating that altered adhesion contributed to, but was not the sole reason for the VPA mediated inhibition of motility. In addition it is shown that the actomyosin cytoskeleton of VPA-treated cells was capable of contraction upon exposure to ATP, indicating that the reduced motility of VPA-treated cells was not caused by an inhibition of actomyosin contraction. On the other hand, VPA caused a redistribution of the actin severing protein gelsolin, and left the cells unable to respond to treatment with a gelsolin-peptide known to reduce the amount of gelsolin bound to phosphatidylinositol bisphosphate (PIP2), leaving a larger amount of the protein in a potential actin binding state. These findings indicate that VPA affects cell morphology and motility through interference with the dynamics of the actin cytoskeleton.
authors: Institute of Molecular Pathology, University of Copenhagen, Panum Institute, Denmark. psw@plab.ku.dk
authors: P S
authors: PS
authors: Walmod
authors: G
authors: G
authors: Skladchikova
authors: A
authors: A
authors: Kawa
authors: V
authors: V
authors: Berezin
authors: E
authors: E
authors: Bock
mesh_terms: D000199:Actins / Q000187:drug effects / Q000502:physiology*; D000205:Actomyosin / Q000187:drug effects; D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D000927:Anticonvulsants / Q000494:pharmacology*; D002448:Cell Adhesion / Q000187:drug effects; D015815:Cell Adhesion Molecules / Q000494:pharmacology; D002465:Cell Movement / Q000187:drug effects; D048429:Cell Size / Q000187:drug effects; D002478:Cells, Cultured; D015638:Cytochalasin D / Q000494:pharmacology; D003598:Cytoskeletal Proteins / Q000494:pharmacology; D003599:Cytoskeleton / Q000502:physiology*; D004305:Dose-Response Relationship, Drug; D005347:Fibroblasts / Q000166:cytology / Q000187:drug effects; D051416:Focal Adhesion Protein-Tyrosine Kinases; D018260:Gelsolin / Q000494:pharmacology; D018613:Microscopy, Confocal; D008856:Microscopy, Fluorescence; D015739:Nocodazole / Q000494:pharmacology; D017830:Octoxynol / Q000494:pharmacology; D051419:Paxillin; D010455:Peptides / Q000378:metabolism; D010750:Phosphoproteins / Q000494:pharmacology; D019000:Phosphotyrosine / Q000494:pharmacology; D011505:Protein-Tyrosine Kinases / Q000494:pharmacology; D013723:Teratogens / Q000494:pharmacology*; D013997:Time Factors; D014357:Trypsin / Q000494:pharmacology; D014404:Tubulin / Q000378:metabolism; D014635:Valproic Acid / Q000031:analogs & derivatives / Q000494:pharmacology*; D016596:Vinculin / Q000494:pharmacology
chemical_list: D000199:Actins; D000927:Anticonvulsants; D015815:Cell Adhesion Molecules; D003598:Cytoskeletal Proteins; D018260:Gelsolin; D051419:Paxillin; D010455:Peptides; D010750:Phosphoproteins; D013723:Teratogens; D014404:Tubulin; D016596:Vinculin; D019000:Phosphotyrosine; D015638:Cytochalasin D; D014635:Valproic Acid; D000255:Adenosine Triphosphate; D017830:Octoxynol; D000205:Actomyosin; D011505:Protein-Tyrosine Kinases; D051416:Focal Adhesion Protein-Tyrosine Kinases; D014357:Trypsin; D015739:Nocodazole