Figure 5. Acetyl-cinobufagin inhibits EMT through the STAT3 signaling pathway. (A, B) Molecular docking of acetyl-cinobufagin to the STAT3 binding sites. (C) Expression of proteins involved in the STAT3 signaling pathway as detected by Western blot analysis. (D) The subcellar location of STAT3 was examined by immunofluorescence staining and confocal laser scanning microscopy (CLSM) in BT-549 cells. (E) The levels of STAT3 protein in the cytoplasm and nuclei were determined by immunoblotting analysis after extraction from BT-549 cells. (F) BT-549 cells treated with IL6 for 30 min after treatment with acetyl-cinobufagin for 10-20 h; expression levels of proteins associated with STAT3 and EMT signaling pathways as detected by Western blot analysis. (G) STAT3 knockdown in BT-549 cells treated with control, IL6 or IL6 + acetyl-cinobufagin (1.0 μM), expression levels of proteins related to STAT3 and EMT signaling pathways as detected by Western blot analysis. (H) Evaluation of metastatic abilities of BT-549 and Hs578T after knockdown of STAT3.