Shikonin Induces Apoptosis, Necrosis, and Premature Senescence of Human A549 Lung Cancer Cells through Upregulation of p53 Expression

Figure 3

Effects of shikonin on activating caspase-3 cleavage and cellular senescence in A549 cells. (a) Colorimetric analysis. Shikonin (SHK) (2.5 μg/mL) soundly elevated caspase-3 activity by 2.12-fold compared with the Cont. (b) Flow cytometric study. Cells treated with SHK generally expressed higher capsase-3 activity by (peak of capsase-3 activity deviating to the right). (c) Senescence-associated β-galactosidase (SA-β-Gal) activity. SHK-treated cultured cells contained more positive cells (green color) compared with the Cont by SA-β-Gal staining. Scale bar indicated as 20 μm. (d) Quantitative analysis of cellular senescence from SA-β-Gal staining. The ratio of positive labeling cells was significantly higher in shikonin-treated cells. Values were obtained from three independent experiments and represented as mean ± S.E.M. Significant difference is indicated by and versus Cont.

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