Fig. 3

Increased expression of OPN in BEAS-2B cells and U937* macrophages exposed to Nano-CuO. BEAS-2B cells, U937* macrophages, or co-culture of BEAS-2B and U937* macrophages at a ratio of 1:1 or 9:1 (BEAS-2B:U937*) were exposed to 0.5 and 1 µg/mL of Nano-CuO for 12 h. After treatment, the cells and conditioned media were collected. Cells without treatment were used as control. Full-length OPN (66 kDa) in the cells and cleaved OPN (40 kDa N-terminal fragment) in the conditioned media were detected by Western blot. Equal protein loading was verified by β-actin expression (a and b) or Coomassie Brilliant Blue staining (c and d). a and c were the results of a single experiment. b and d were results of three independent experiments. Data represent mean ± SE (n = 3). * Significant difference as compared to the control group, p < 0.05