Participation of ADAM17 in TGF-β-induced CTGF expression in human lung epithelial A549 cells. (A) A549 cells were processed with the ADAM17 inhibitor TAPI-0 (10 μM) for 20 min. After 20 min, the cells were stimulated with TGF-β (10 ng/mL) for an additional 6 h. CTGF and α-tubulin levels were detected in cell lysates through Western blotting. Data are expressed as mean ± SEM of three independent experiments. * p < 0.05, compared with the TGF-β group without TAPI-0 treatment. (B) A549 cells were transfected with 25 nM control siRNA (con siRNA) and 25 nM ADAM17 siRNA for 48 h before they were stimulated with TGF-β (10 ng/mL) for an additional 6 h. CTGF and α-tubulin levels were detected in cell lysates through Western blotting. Results are expressed as mean ± SEM of three independent experiments. * p < 0.05, compared with TGF-β plus the control siRNA group. (C) Cells were stimulated with TGF-β (10 ng/mL) for 0–30 min, and then ADAM17 phosphorylation and ADAM17 were detected in cell lysates through Western blotting. Results are presented as mean ± SEM of four independent experiments. * p < 0.05, compared with the control group without TGF-β treatment.