Physiological levels of hydrostatic pressure alter morphology and organization of cytoskeletal and adhesion proteins in MG-63 osteosarcoma cells.
The response of human MG-63 osteosarcoma cells to physiological levels of hydrostatic pressure was studied. Cell cultures were subjected to a 20-min, 4-MPa hydrostatic pressure pulse. Adhesion was measured at 20 min and 2 h post-hydrostatic pressure. Morphometric measurements of cell shape and immunofluorescent assays of cytoskeletal and adhesion proteins were done pre- and post-hydrostatic pressure. Pressure-treated cells showed increased adhesion (resistance to deadhesion by trypsinization)-with increased recovery time. Indirect immunofluorescence demonstrated increased heterotypic adhesion receptor at cell-cell interfaces and increased alpha 3, beta 1-integrin at cell-substrate interfaces. Indirect immunofluorescence demonstrated depolymerization of alpha-tubulin, vimentin, and actin during the pressure pulse. Actin reorganization was slower than that of alpha-tubulin and vimentin, with stress filaments not well organized even after 1 h postpressure. The depolymerization of alpha-tubulin, vimentin, and actin observed at relatively low levels of hydrostatic pressure suggests disintegration of the integrin-cytoskeletal attachment complex. The increased resistance of the cells to trypsinization and the increase in both heterotypic adhesion receptor and the alpha 3, beta 1-integrin at cell interfaces suggest that cells compensate for loss of cytoskeletal integrity by increasing attachment to both adjacent cells and the extracellular matrix.
Haskin
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C
Department of Cellular and Structural Biology, University of Texas Health Science Center, San Antonio, 78284-7762.
Cameron
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I
Athanasiou
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K
D001842:Bone and Bones / Q000166:cytology / Q000502:physiology*; D002448:Cell Adhesion / Q000502:physiology*; D015815:Cell Adhesion Molecules; D002470:Cell Survival; D003598:Cytoskeletal Proteins / Q000302:isolation & purification; D003599:Cytoskeleton / Q000502:physiology*; D005455:Fluorescent Antibody Technique; D006801:Humans; D006874:Hydrostatic Pressure; D016023:Integrins / Q000302:isolation & purification; D009024:Morphogenesis / Q000502:physiology*; D012516:Osteosarcoma; D013997:Time Factors; D014407:Tumor Cells, Cultured
D015815:Cell Adhesion Molecules; D003598:Cytoskeletal Proteins; D016023:Integrins