Fig. 4.

Effect of bortezomib and ouabain treatment on caspase activity. A and B, Caspase 3/7 activity in thyroid cancer cells was increased with bortezomib (A) and ouabain (B) treatment. FTC-133 and 8505c cells were plated in 96-well plates and then treated with 20 nm bortezomib (T) or vehicle (V). XTC-1 cells were plated in 96-well plates and treated with ouabain at 50 nm concentration. At 48 h later, caspase 3/7 activity was determined. Error bars indicate mean ± sd. **, Mean P < 0.01. C, Ouabain induces cell cycle arrest in thyroid cancer cell lines by increasing the number of cells in G2M.