Herbal Extract SH003 Suppresses Tumor Growth and Metastasis of MDA-MB-231 Breast Cancer Cells by Inhibiting STAT3-IL-6 Signaling
Figure 6
SH003 inhibits STAT3 target gene expression. ((a) and (b)) MDA-MB-231 cells were treated with the indicatives at 50 or 500 μg/mL for 24 hours and then subjected to western blots with the antibodies indicated. Tubulin was detected as a loading control. (c) MDA-MB-231 cells were treated with the indicatives at 500 μg/mL for 24 hours and then subjected to real-time PCR for IL-6 mRNA expression levels. Experiments were performed in triplicate. Bars indicate means and standard deviations. . (d) MDA-MB-231 cells were treated with the indicatives at 500 μg/mL for 24 hours and then harvested culture media. IL-6 levels were analyzed with ELISA assay. Experiments were performed in triplicate. Bars indicate means and standard deviations. . (e) Cells were treated with SH003 for 6 hours and then subjected to chromatin immunoprecipitation assays to test STAT3 interaction with IL-6 promoter. (f) A schematic model for anti-TNBC roles of SH003. TNBC has highly metastatic characteristics with constitutively active STAT3. SH003 selectively targets STAT3-dependent IL-6 production, resulting in the inhibition of TNBC growth and metastasis.
