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. 2012 Dec 11;7(12):e51764. doi: 10.1371/journal.pone.0051764

Figure 4. Quercetin potentiates DOX-induced apoptosis of SMMC7721 cells in a p53-dependent manner.

Figure 4

(A) p53 and PUMA expressions were assessed by western blot in SMMC7721 cells treated with DOX (1 µM) and/or quercetin (20 µM) for 24 h. β-actin was used as an internal control. (B) The luciferase assay of DOX- and quercetin-induced p53 activation. SMMC7721 cells were pretreated for 1 h with 2 µM of pifithrin-α, and then treated with DOX (1 µM) or quercetin (20 µM) for 12 h. p53 activity was determined by luciferase activity assay. Data are presented as mean ± S.D. of three independent experiments. *P<0.01 vs. DOX-treated cells. **P<0.001 vs. DOX + quercetin-treated cells. (C) SMMC7721 cells were pretreated with 2 µM of pfithrin-α for 1 h, and then treated with DOX (1 µM) and/or quercetin (20 µM) for 24 h. Apoptosis rates were assayed by Annexin V/PI staining. Data are presented as mean ± S.D. of three independent experiments. *P<0.001 vs. DOX-treated cells. **P<0.01 vs. DOX-treated cells. ***P<0.001 vs. DOX + quercetin-treated cells.