Hyperthermia-induced reorganization of microtubules and microfilaments and cell killing in CHO AA8 cell line
Abstract:
The aim of this study was to elucidate the effects of hyperthermic treatment on cell morphology and the cytoskeleton in CHO AA8 cell line. The effects of exposure to elevated temperature were analyzed in CHO AA8 cell line by fluorescence microscopy and flow cytometry. The 30min, at 44.5°C heat shock treatment resulted in the collapse of microtubules (MTs) and microfilaments (MFs) around the nucleus followed by their recovery 24h after heating. The initial collapse of these cytoskeletal systems, observed 15min after treatment, was accompanied by the appearance of cells with reduction of volume, shrunken cytoplasm and condensed chromatin. 24h afterwards, there was the increase in the number of cells with restored and extended MT and MF cytoskeletons. Most of them were larger in size compared to the control cells and had multiple nuclei. 48h after heat shock the highest number of the giant cells with alternation in nuclear morphology was seen. Flow cytometry analysis revealed the increase in the number of cells with externalized phosphatidylserine 24h and 48h after hyperthermic treatment. These results suggest that following heat shock, CHO AA8 cells undergo mitotic catastrophe that presumably represents one of the events resulting in apoptosis.