Figure 3. The effects of IL-6/STAT3 on cell invasion and migration.

(A) The levels of IL-6 in CM from MDA-MB-231-2A irradiated with 6 Gy followed by 0–120 h of recovery time were measured using an ELISA. (B) The effects of neutralisation of IL-6 antibody on CM-induced migration (left) and invasion (right) of non-irradiated MDA-MB-231 cells were examined using wound-healing and Boyden chamber assays, respectively. The numbers of invasive/migrated cells was quantified. A p value of <0.01 (**) indicates significant differences between CM-treated and untreated samples. A p value of <0.01 (##) indicates a significant difference between the group receiving CM alone and the CM + IL-6 Ab cells. (C) Western blot analysis was performed to determine the levels of phospho-STAT3 in MDA-MB-231-2A cells treated with radiation followed by 0–48 h recovery time. (D) The 4XM67TATA-Luc plasmid and the control SV-Luc plasmid were transfected into MDA-MB-231-2A cells. Then, the luciferase activity was measured after radiation. (E) Left: MDA-MB-231-2A cells were transfected with scrambled (NC) or STAT3 siRNA followed by radiation. The levels of phospho-STAT3 and STAT3 were ascertained by western blot analyses. Right: IL-6 secreted from cells transfected with STAT3 siRNA followed by radiation was measured using an ELISA. (F) Treatment was described in Figure 3E. The effects on MDA-MB-231 cell invasion were examined using a Boyden chamber assay. The population of invading cells was quantified. A p value of <0.01 (**) indicates significant differences between CM-treated and untreated samples. A p value of <0.01 (##) indicates a significant difference between CM from non-transfected and siRNA-transfected cells. Quantification of western blot bands was performed using densitometry, and the phospho-STAT3/STAT3 ratio to actin is indicated.