Figure 6.

MLN4924 enhances activity of the alkylating agents in CLL. (a) CLL cells (N=10) were co-cultured with CD40L-expressing stroma for 24 h, followed by incubation with the indicated compounds or with vehicle control for 48 h. Apoptosis within the CD19⁺ subset of cells was determined by Annexin V and 7-AAD staining. (b) CLL cells (N=8) were co-cultured with CD40L-expressing stroma in the presence or not of 25 ng/ml IL-21 for 72 h. Thereafter, cells were treated as shown. Cells were collected at the indicated time points and assayed for apoptosis (data are mean±S.E.). (c) CLL cells were co-cultured with CD40L-expressing stroma for 24 h, followed by incubation with the indicated drugs or with vehicle control for 24 h. Cells were lysed and subjected to immunoblotting (a representative image out of four independent experiments is shown). (d) CLL cells (N=8) were co-cultured with CD40L-expressing stroma in the presence or not of 25 ng/ml IL-21 for 72 h. Thereafter, cells were treated with drugs alone or in combination for 24 h and assayed by FACS analysis for cell cycle profiling and cell population with more than 4N DNA content. (e) CLL cells were co-cultured with CD40L-expressing stroma 24 h, treated with the indicated for 24 h and subjected to immunoblotting. A representative image of three independent experiments is shown. (f) Cells with del(17p) (N=10) or not were treated with drugs as above for 48 h and assayed for apoptosis as above; cells without del(17p) were lysed after 24 h of incubation with drugs and subjected to immunoblotting. Data are mean±S.E. **P<0.01 and *P<0.05 compared with either single drug