Change in the localization of heat shock protein 27 (HSP 27) in BG-1 human ovarian cancer cells following treatment by the ether lipid ET-18-OCH3.

We have demonstrated a higher nuclear protein content in the hypodiploid fraction of BG-1 human ovarian cancer cells following treatment with one of the ether lipids, ET-18-OCH3. In this study, we have attempted to identify the overexpressed nuclear protein induced in those dying or dead cells in the hypodiploid fraction and its localization before and after ET-18-OCH3 treatment. The pattern of nuclear proteins was analyzed by two-dimensional polyacrylamide gel electrophoresis (2-D PAGE) before and after ET-18-OCH3 treatment. The partial amino acid sequence of the most dominantly and consistently up-regulated protein spot after ET-18-OCH3 treatment was determined and it was found to be heat shock protein 27 (HSP27). Immunofluorescence staining disclosed that HSP27 localizes in the cytoplasm of the BG-1 cells before ET-18-OCH3 treatment. Condensation of HSP27 around the nuclei was observed following treatment by ET-18-OCH3. Ultimately, the nuclei of the cells in the hypodiploid fraction were stained by immunofluorescent HSP27. These results indicate that change of the localization of HSP27 may play an important role as a component of the signal transduction pathways affected by ether lipids.