Effects of hyperthermia on the cytoskeleton and focal adhesion proteins in a human thyroid carcinoma cell line

✍ Scribed by Shih-Horng Huang; Kai-Jian Yang; Jiahn-Chun Wu; King-Jeng Chang; Seu-Mei Wang

• Publisher: John Wiley and Sons
• Year: 1999
• Tongue: English
• Weight: 830 KB
• Volume: 75
• Category: Article
• ISSN: 0730-2312
• DOI: 10.1002/(sici)1097-4644(19991101)75:2<327::aid-jcb14>3.0.co;2-g

✦ Synopsis

Hyperthermia is reported to act as a sensitizer to chemotherapeutic drugs in the treatment of cancer. Thyroid follicular carcinoma were used to elucidate the effects of hyperthermic treatment (41-43°C) on cell morphology, cytoskeleton, and the focal adhesion complex. The critical temperature that resulted in inhibition of cell proliferation as the cell number in the same area did not increase over a 23 h time course and irreversible changes in cell morphology was 42-43°C. An immunofluorescence study on heat-treated cells (43°C, 1-5 h) demonstrated that depolymerization of actin filaments, intermediate filaments, and microtubules accounted for the rounding-up of cells and detachment from the substratum. Characteristic staining patterns for integrin ␣v, focal adhesion kinase, and vinculin were noted in untreated cells, but the immunoreactive intensities for these proteins became weaker with time of heat treatment. Anti-phosphotyrosine staining revealed less immunoreactivity in the focal adhesions in treated cells compared with control cells. The disappearance of integrin ␣v from the cell surface may result in inhibition of integrin-mediated activation of focal adhesion kinase, which results in dephosphorylation of focal adhesion components and its disassembly. These results indicate that hyperthermia induces disruption of integrin-mediated actin cytoskeleton assembly and, possibly, of other integrin-mediated signaling pathways.