FIGURE 1.

Effect of cancer‐associated fibroblasts (CAFs) on the progression and acquisition of drug resistance of non–small cell lung cancer (NSCLC) through activation of STAT3 signaling and induction of epithelial‐mesenchymal transition (EMT). A, PC9 cells were cocultured with CAFs for 7 d, and the expression level of pSTAT3 was analyzed by Western blotting. B, PC9 cells alone, CAF1 cells alone, or PC9 cells plus CAF1 cells were subcutaneously implanted into the flanks of nude mice, and the tumor sizes were monitored. Each group consisted of five mice. Data shown are the means ± SE; **p < 0.01. C, HCC4011 cells were cocultured with CAFs, and morphological changes were observed. D, HCC4011 and H2009 cells were cocultured with CAFs for 72 h, and the expression levels of EMT markers were analyzed by Western blotting. E, PC9 cells alone or PC9 cells plus CAF1 cells were subcutaneously implanted into the flanks of nude mice. When the tumors reached a diameter of approximately 150 mm³, the mice were treated with 5 mg/kg of osimertinib five times a week. The tumor volumes were then determined on the indicated days after the start of treatment. Each group consisted of seven mice. Data shown are the means ± SE; **p < 0.01