The ERK, JNK, and NF-κB signaling is crucial for the induction of IL-8 by cigarette smoke extract (CSE) in human bronchial epithelial cells. Cells were exposed to medium alone or 3% CSE for 24 (a), 6 ((b), (c)), or 12 hours (d) with pretreatment with an ERK inhibitor (PD98059; PD, 10 μM), a JNK inhibitor (SP600125; SP, 10 μM), or a NF-κB inhibitor (BAY 11-7085; BAY, 10 μM). Protein expression was analyzed by Western blotting. Activation of ERK (b) or JNK (c) was indicated by increased phosphorylation of these kinases in cell lysates, whereas activation of NF-κB (d) was indicated by increased presence of p65 subunit in the cell nucleus. versus control (Con). versus CSE without inhibitor pretreatment.
