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 4

Intracellular expression of HSP27 and secretion of IL-6 and HSP27 in OVCAR-3 and SK-OV-3 cells in the presence of brefeldin A. (a, b, and c) OVCAR-3 cells were incubated with 80 nM brefeldin A and IL-6 secretion (a), intracellular HSP27 (b), and secreted HSP27 (c) were determined by ELISA (a and c) and Western blotting (b), respectively, at indicated time points. (d, e, and f) SK-OV-3 cells were incubated with 80 nM brefeldin A and IL-6 secretion (d), intracellular HSP27 (e), and secreted HSP27 (f) were determined by ELISA (d and f) and Western blotting (e), respectively, at indicated time points. Intracellular HSP27 signal was normalized to β-actin. All values were standardized to vehicle incubated controls (control = 1.0). 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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