Inhibitory effect of tranilast on cancer‐associated fibroblast (CAF)‐induced pSTAT3 upregulation and epithelial‐mesenchymal transition (EMT) in non–small cell lung cancer (NSCLC) cells. A, NSCLC cell lines were cultured in the presence of tranilast for 7 d, and the expression level of pSTAT3 was analyzed by Western blotting. B, After tranilast treatment for 48 h, the mRNA expression levels of IL‐6 in the CAFs were measured by real‐time PCR. Each measurement was conducted in triplicate, and the data are representative of three independent experiments (mean ± SE) conducted using different CAF sublines (CAF1, CAF2, and CAF3). C, Secretion of IL‐6 in the culture medium of the CAFs was assessed by Western blotting. D, NSCLC cell lines and CAFs were cocultured in the presence of tranilast for 7 d, and the EMT status was analyzed by Western blotting. E, HCC4011 cells were treated with TGF‐β, and morphological changes were observed. F, After TGF‐β treatment for 72 h, the EMT status in the HCC4011 and H2009 cells was analyzed. G, HCC4011 and H2009 cells were treated with TGF‐β in the presence or absence of tranilast for 72 h, and the EMT status was analyzed by Western blotting