Figure 2.

Combination treatment with bortezomib and micelle-thiostrepton induces cell death in MDA-MB-231-luc tumor xenografts, as determined by promotion of apoptotic markers. (A) Immunhistochemical analysis of four individual tumors (two from non-treated and two from combination treated groups) for cleaved caspase-3 expression (counterstained with hematoxylin). Cleaved-caspase-3 is evidently enhanced in combination-treated tumors, identified by the presence of larger numbers of dark, DAB-stained clusters. Control slides were incubated with rabbit IgG primary antibodies. Blue bars represent 100 µm (20 x). (B) Protein gel blotting of a panel of individual tumor homogenates (five of non-treated and five of combination-treated) against cleaved PARP and β-actin. Cleaved PARP expression is increased in tumors treated with a combination of thiostrepton and bortezomib.