Cytoskeletal modulation, and changes in cytoskeletal actin cytoskeleton during regulatory volume decrease in human cervical cancer HT-3 cells

Actin cytoskeleton was visualized by confocal microscopy after fluorescence isothiocyanate (FITC)-phalloidin labeling. Total, and Triton-insoluble and Triton-soluble F-actin levels were measured by flow cytometry, and by sodi um-dodecylsulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and densito metric scanning. With cell swelling, the total cellular F-actin content fel l by nearly 15 %. Pretreatment with cytochalasin B significantly prolonged the regulatory volume decrease (RVD) responses, and potentiated the reducti on of total F-actin content in hypotonic stress. Phorbol 12-myristate 13-ac etate (PMA) induced a slow but progressive polymerization of F-actin, but w as not able to prevent the perturbation of RVD induced by cytochalasin B. T hese data support that the functional integrity of actin cytoskeleton appea rs to be required for effective RVD in HT-3 cells.