Fig 2.

Protective effect of the IGF/Akt pathway against apoptosis induced by proteasome inhibition. (A) IGF-1 (200 ng/ml) lowers the sensitivity to PS-341 (10 nM). Cells were serum-starved overnight and then incubated with or without PS-341 in serum-free medium for additional 18 h. (B) PS-341 (5 and 10 nM)-induced cell death (quantified by MTT, mean ± SD) in MM.1S cells transfected with a vector expressing constitutively active Akt (open bars), or control vector (filled bars). After overnight serum starvation, cells were incubated with or without PS-341 in serum-free medium for additional 18 h.