Figure 2.

CLL cells undergo DNA damage and checkpoint activation in response to treatment with MLN4924. (a) CLL cells were co-cultured with CD40L-expressing stroma in the presence or absence of 25 ng/ml IL-21 for 72 h. Thereafter, cells were treated with 0.05–1 μM MLN4924 or vehicle control, collected at the indicated time points and subjected to immunoblotting. Images representative of four independent experiments are shown. (b) CLL cells (N=4) were co-cultured as above with 25 ng/ml IL-21 followed by a 6-h incubation with 1 μM MLN4924. Cells were immunostained with γH₂AX and Ki-67 antibodies. Nuclei were counterstained with 4,6-diamino-2-phenylindole. A representative case is shown