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. 2019 Mar 12;10(21):2068–2085. doi: 10.18632/oncotarget.26699

Figure 5. OSM and IL-1β activate separate signaling pathways and synergistically induce IL-6 secretion.

Figure 5

(A) IL-1β alone promotes IL-6 production in MDA-MB-231 and MCF7 cells, while a combination of OSM and IL-1β causes a synergistic response in IL-6 secretion. T47D cells do not produce IL-6 in any of these conditions. (B) Reduced IL-6 scale to allow visualization of MCF7 cell-IL-6 induction. (C) A 20-minute cytokine treatment with OSM induces the phosphorylation of STAT3 but not p65, while ERK is moderately phosphorylated. MCF7 cells have a weak pSTAT3 induction in response to OSM. A 20-minute cytokine treatment with IL-1β on the other hand induces the phosphorylation of p65 but not STAT3. (D) STAT3 siRNA suppressed OSM induction of IL-6 production as assessed by ELISA in MDA-MB-231 cells. Data expressed as mean ± SEM, and significance assessed by one-way ANOVA with Tukey’s post-test. *p < 0.05. (E) MCF7 cells were treated with OSM and/or IL-1β for 48 hours, and the cell lysates were run through an immunoprecipitation with an ER pulldown. The eluate was then immunoblotted with the input for STAT3. Lysates collected from MCF7 cells treated with OSM or with both cytokines have significantly reduced ER-STAT3 interaction. Data expressed as mean ± SEM, and significance assessed by one-way ANOVA with Tukey’s post-test. *p < 0.05.