Figure 1. Sorafenib and Sodium Valproate interact to kill GBM cells. (A) GBM6 cells were treated with vehicle or Sodium Valproate (1 mM). Thirty minutes later cells were treated with vehicle or sorafenib (3 μM; 6 μM). Cells were isolated 24 h and 48 h later. Viability was determined by trypan blue exclusion (n = 3, ± SEM) *p < 0.05 greater than corresponding vehicle control treated cells. (B) GBM12 cells were treated with vehicle or Sodium Valproate (1 mM). Thirty minutes later cells were treated with vehicle or sorafenib (3 μM; 6 μM). Cells were isolated 48 h later. Viability was determined by trypan blue exclusion (n = 3, ± SEM) *p < 0.05 greater than corresponding vehicle control treated cells. (C) GBM15 and GBM14 cells were treated with vehicle or Sodium Valproate (1 mM). Thirty minutes later cells were treated with vehicle or sorafenib (3 μM; 6 μM). Cells were isolated 48 h later. Viability was determined by trypan blue exclusion (n = 3, ± SEM) *p < 0.05 greater than corresponding vehicle control treated cells. Upper blot: GBM15 cells were treated with the indicated drugs and cells isolated 24 h later for determination of P-p70 S6K and P-mTOR levels. (D) GBM5 cells were treated with vehicle or Sodium Valproate (1 mM). Thirty minutes later cells were treated with vehicle or sorafenib (1 μM; 2 μM; 3 μM; 6 μM). Cells were isolated 24 h and 48 h later. Viability was determined by trypan blue exclusion (n = 3, ± SEM) *p < 0.05 greater than corresponding vehicle control treated cells. (E) GBM5 and GBM6 cells plated as single cells were treated with vehicle or Sodium Valproate (1 mM). Thirty minutes later cells were treated with vehicle or sorafenib (2 μM–6 μM, as shown). The media was changed 48 h later to drug free media and colonies permitted to form for the next 14 d. (n = 3, ± SEM) *p < 0.05 greater killing corresponding vehicle control treated cells.