Figure 4 | Scientific Reports

Figure 4

From: Cytarabine-induced differentiation of AML cells depends on Chk1 activation and shares the mechanism with inhibitors of DHODH and pyrimidine synthesis

Figure 4

Down-regulation of Chk1 reduces the effects of cytarabine on the expression of differentiation markers and S-phase arrest. U937 cells were transfected with siRNA against CHK1, and respective nontargeting siRNA was used as a negative control. AICAr (AIC) (0.2 mM), brequinar (Bq) (0.5 µM) and AraC (100 nM) were added 24 h after transfection. (A) Total cell lysates were isolated 3 or 48 h after the addition of agents and analyzed by Western blotting for the level of Chk1. Western blot analyses are shown for each of the three independent experiments. (B) The number of viable cells, the expression of differentiation markers and the cell cycle progression were analyzed by flow cytometry 72 h after addition of agents. (C) Representative histograms of propidium-labeled cells analyzed by flow cytometry. (D) Percentage of cells in G0/G1, S, and G2/M-phases of the cell cycle. Results are mean ± S.E. (error bars) of at least three independent experiments. *, p < 0.05 (Student's t-test) compared with control (ctrl).

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