Molecular mechanism of OPN induction after exposure to bleomycin.

<p>(A) A549 were exposed to 10 µg/mL bleomycin or PBS for 24 h. Western blotting was used to detect phospho-specific ERK1/2, ERK1/2, phospho-specific SAPK/JNK, SAPK/JNK, phospho-specific p38 MAPK and p38 MAPK. (B) A549 were pretreated with PD98059 (50 µM) or DMSO for 1 h, and subsequently exposed to 10 µg/mL bleomycin for 48 h. Western blotting was used to detect phospho-specific ERK1/2 and ERK1/2. (C) A549 were pretreated with U0126 (50 µM) or DMSO for 1 h, and subsequently exposed to 10 µg/mL bleomycin for 48 h. Western blotting was used to detect phospho-specific ERK1/2 and ERK1/2. (D) A549 were pretreated with PD98059 (50 µM) or DMSO for 1 h, and subsequently exposed to 10 µg/mL bleomycin or PBS for 48 h. <i>OPN</i> mRNA was assessed by qRT-PCR. (E) A549 were pretreated with U0126 (50 µM) or DMSO for 1 h, and subsequently exposed to 10 µg/mL bleomycin or PBS for 48 h. <i>OPN</i> mRNA was assessed by qRT-PCR. (F) A549 were pretreated with PD98059 (50 µM) or DMSO for 1 h, and subsequently exposed to 10 µg/mL bleomycin or PBS for 48 h. OPN concentrations in cell culture media were determined by ELISA. (G) A549 were pretreated with U0126 (50 µM) or DMSO for 1 h, and subsequently exposed to 10 µg/mL bleomycin or PBS for 48 h. OPN concentrations in cell culture media were determined by ELISA. Data are presented as mean ± S.E. *, P<0.05; **, P<0.01.