Changes in cell-substratum adhesion and nuclear-cytoskeletal anchorage during cytodifferentiation of BeWo choriocarcinoma cells.
Changes in the substratum anchorage of cells and nuclei were examined during methotrexate (MTX)-induced cytodifferentiation of BeWo human choriocarcinoma cells. During this process cytotrophoblast-like cells (CTLs) transform into giant mono- and multinucleated syncytiotrophoblast-like cells (STLs). Cells treated with MTX for 24 h exhibited significantly faster rates of substratum detachment by EDTA, trypsin-EDTA, EDTA-glycine, and DMSO than did uninduced controls. The decrease in cell-substratum adhesiveness occurred prior to the onset of morphological transformation. By 48 h, when morphological transformation was first observed, there had occurred a marked change in nuclear-cytoskeletal anchorage to the substratum, as evidenced by a difference in sensitivity of Triton-extracted STL and CTL monolayers to detachment by KI. STL monolayers were completely detached within 5 min of exposure to 0.3 M KI, while CTL monolayers remained firmly attached to the substratum for at least 3 h. KI-extracted residues were examined by electron microscopy and found to consist of nuclear shells attached to intermediate filaments. When cytoskeletal residues and KI-extracted proteins of STL and CTL cells were compared by two-dimensional polyacrylamide gel electrophoresis (PAGE), qualitative and quantitative differences were seen in a number of minor components. Thus the sensitivity of STL nuclear-cytoskeletal monolayers to removal by KI, an effective actin depolymerizing agent, may involve changes in the organization, stability, or interactions of actin with other components of the cytoskeletal framework.
D002448:Cell Adhesion / Q000187:drug effects; D002454:Cell Differentiation / Q000187:drug effects; D002467:Cell Nucleus / Q000648:ultrastructure*; D002478:Cells, Cultured; D002822:Choriocarcinoma / Q000473:pathology* / Q000648:ultrastructure; D003599:Cytoskeleton / Q000648:ultrastructure*; D004591:Electrophoresis, Polyacrylamide Gel; D005260:Female; D006801:Humans; D008727:Methotrexate / Q000494:pharmacology*; D008855:Microscopy, Electron, Scanning; D011247:Pregnancy
D008727:Methotrexate