FIGURE 4.

SHK-induced senescence is specifically dependent on ROS generation. (A) ROS generations in A549 and H1299 cells were detected by flow cytometry after 1 h of NAC (2 mM) pretreatment and 72 h of SHK treatment. (B) Cell viabilities of A549 and H1299 were determined in the presence of 2 mM NAC pretreatment for 1 h. (C) The proportions of senescence A549 and H1299 cells were determined using SA-β-Gal staining after NAC pretreatment and SHK treatment. (D) Expressions of p53 and p21^waf in A549 cells, and expression of p21^waf in H1299 cells were detected by Western blot after NAC pretreatment and SHK treatment. (E) Representative confocal imaging (scale bar: 25 μm) of double-stained cells after NAC pretreatment and SHK treatment using p-H2A.X (red) and DAPI (blue) staining. ^∗∗P < 0.01, ^∗∗∗P < 0.001 vs. Ctrl (control), ^#P < 0.05, ^##P < 0.01, ^###P < 0.001 vs. SHK.