Recombinant human opn

Recombinant human OPN was from R&D system and was used at 1 µg/mL. Inhibition of the NF‐κB activity was conducted with a specific inhibitor (inhibitor of IKK2 (AS602868), iNF‐κB), a gift from Dr JF Peyron.

NSCLC cells were incubated with recombinant human OPN (100 ng/ml, 200 ng/ml, and 400 ng/ml) (R&D Systems) at 37°C for 120 min. NSCLC cells were treated with Helenalin (Abcam, ab146197, 10 ng/ml) for 1 h.

Bleomycin and tunicamycin were purchased from Sigma-Aldrich (St. Louis, MO, USA). Doxorubicin and thapsigargin were purchased from Wako Pure Chemical Industries, Ltd. (Osaka, Japan). PD98059 and U0126 were purchased from Calbiochem (La Jolla, CA, USA). Anti-phospho-specific p44/42 mitogen-activated protein kinase (MAPK) (extracellular signal-regulated protein kinase1/2 (ERK1/2)), anti-ERK1/2, anti-phospho-specific stress-activated protein kinase (SAPK)/c-Jun NH₂-terminal kinase (JNK), anti-SAPK/JNK, anti-phospho-specific p38 MAPK, anti-p38 MAPK, anti-β-actin, anti-immunoglobulin heavy-chain binding protein (BiP) antibodies and horseradish peroxidase (HRP)-conjugated secondary antibody were purchased from Cell Signaling Technology (Danvers, MA, USA). Recombinant human OPN was purchased from R&D Systems (Minneapolis, MN, USA). Anti-human OPN neutralizing antibody (anti-OPN IgG) and its nonspecific control antibody (control IgG) were purchased from R&D Systems.