Cuc B induced DNA DSBs active G2/M checkpoint mediated by ROS generation.

<p>The generation of ROS in A549 cells after 50, 100, 200₂-DA as described under Materials and Methods (A, B). Effect of Cuc B on STAT3 phosphorylation on Tyr-705 and STAT3 expression were analyzed by Western blot assay (C). A549 cells were treated with 10 mM NAC for 0.5 h followed by treatment with 200 nM Cuc B for 24 h, and the cell cycle was tested (D, E). A549 cells pretreated with 10 mM NAC for 0.5 h and treated with or without 200 nM Cuc B for 24 h. Phosphorylation of Chk1 on Ser-345, Cdc25C on Ser-216, p53 on Ser-15 and protein levels of Chk1, Cdc25C, p53, 14-3-3-σ, Cdk1 were analyzed by Western blot assay (F). ^*<i>p</i><0.05 <i>vs.</i> Cont, ^***<i>p</i><0.001 <i>vs.</i> Cont. Cont, control group.