Different Persistence of the Cellular Effects Promoted by Protein Kinase CK2 Inhibitors CX-4945 and TDB

Figure 2

Duration of CK2 inhibition after TDB or CX-4945 removal from treated cells. CEM or U2OS cells were treated with TDB or CX-4945, as indicated, for 24 h. Then cells were washed and the culture medium was replaced with a fresh one devoid of inhibitors. (a) Cells were cultured for a further time, as indicated, and then lysed. CK2 activity was assessed from 1-2 μg of lysate proteins towards a synthetic CK2-specific peptide. The inhibitor concentration was 3 μM. Activity is shown as percent of control vehicle-treated cells (mean of three independent experiments ± SEM; statistical significance was calculated using unpaired -test between control and treated cells (; ; ; )). (b) Cells were lysed after the first 24 h of culture in the presence of 10 μM inhibitors (upper blots) or cultured for further 24 h after the inhibitor removal (lower blots). 10 μg of lysate proteins was analyzed by WB with the indicated antibodies. A quantification of the pSer129 (mean of three independent experiments ± SEM) normalized to Akt1 total amount is shown in the histograms on the right, where 100% values have been assigned to untreated cells of each experimental protocol.

(a)

(b)