Fig. 5.

AP-1 transcription factor mediates IL-6 expression in response to CXCL1 in OASFs and RASFs. a, b OASFs and RASFs were pretreated with different inhibitors against AP-1 activation (tanshinone, 5 μM; curcumin, 3 μM) for 1 h, then incubated with CXCL1 (10 ng/mL). IL-6 expression was examined by qPCR and Western blot. The quantification of Western blot is provided in the lower panel. c The cell lysates were collected from OASFs and RASFs as described in Fig. 3c, then c-Jun phosphorylation was investigated by Western blot. The quantification of Western blot is provided in the lower panel. d OASFs and RASFs were transfected with c-Jun siRNA for 24 h, then treated with CXCL1 (10 ng/mL) for 24 h. IL-6 expression was analyzed by qPCR. e OASFs were pretreated with inhibitors that target CXCR2 (SB225002, 5 μM), c-Raf (GW5047, 5 μM), ERK (PD98059, 5 μM), MEK (U0126, 3 μM), JNK (SP600125, 3 μM), and p38 (SB203580, 5 μM) for 1 h, then incubated with CXCL1 (10 ng/mL) for a further 24 h. Immunofluorescence staining using the c-Jun antibody monitored nuclear translocation. (In the above experiments, OASFs; n = 10, RASFs; n = 10). Results are expressed as the mean ± SEM. Statistical analysis was conducted by using one-way ANOVA followed by Fisher’s LSD post hoc comparisons tests. *p < 0.05 compared with the respective groups in all figures (control and untreated); ^#p < 0.05 compared to the groups with control (a) and control siR (b) pretreatment followed by CXCL1 incubation