Figure 3.

Effect of long‐term sorafenib pretreatment on natural killer (NK) cell cytotoxicity. NK cells were expanded without treatment or in the presence of sorafenib (1 µg/ml, 3 µg/ml) or dimethylsulphoxide (DMSO) (vehicle control). After expansion, cells were washed twice to remove the drugs and co‐cultured with either K562 ffLuc⁺ cells (n = 5) (a) or Daudi ffLuc⁺ cells (n = 7) (b) at an E : T ratio of 2·5 : 1 for 4 h, ffLuc⁺ cells alone served as controls. Each condition was measured in triplicate. Data were normalized, setting luciferase activity of ffLuc⁺ target cells as 100%. Data shown represent means of triplicates with standard error of the mean (s.e.m.) of n = 5 (a) or n = 7 (b) independent experiments as indicated. Paired Student's t‐test using raw data was used for statistical evaluation. *P < 0·05; *¹ P < 0·05 in comparison to all other groups.