Heat Shock Protein HSP27 Secretion by Ovarian Cancer Cells Is Linked to Intracellular Expression Levels, Occurs Independently of the Endoplasmic Reticulum Pathway and HSP27’s Phosphorylation Status, and Is Mediated by Exosome Liberation

Figure 3

Intracellular expression and secretion of HSP27 in heat shock-treated SK-OV-3 cells. (a) SK-OV-3 cells were treated with a 37°C/39°C/37°C heat shock cycle for 24 h each temperature (cycle) and a unique 39°C heat shock for 4 h (4 h), respectively. Cells incubated by 37°C for 72 h and 4 h, respectively, served as controls. Relative intracellular HSP27 expression was determined by Western blotting. HSP27 signal was normalized to β-actin. (b) Representative Western blots of experiments as described in (a). (c) Secreted HSP27 concentration in supernatants of SK-OV-3 cells determined by ELISA. Cells were treated as described in (a). Graphs of samples were calculated as the mean ± SD. values were determined by Student’s -test with () and ( ) given as significant.

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