Fig. 4

The p53 inhibitor, pifithrin-α and Knockdown of p53 protein expression by p53 siRNA, reversed the action of evodiamine (EVO) in SW1736 cells but not in KAT4B cells. A Morphological alterations in EVO-treated SW1736 cells after the addition of pifithrin-α. SW1736 cells were treated with pifithrin-α for 30 min followed by EVO (8 µM) stimulation for 24 h. The morphology of SW1736 cells was observed microscopically via Giemsa staining. Scale bar (), 100 μm (B) Pifithrin-α (P) reversed the cytotoxic effect of EVO (E) against the viability, hyperdiploid cells, and G2/M arrest of SW1736 cells but not KAT4B cells. Data are presented as the percentage of the control. C Introduction of p53 siRNA reduced endogenous p53 protein in both the SW1736 and KAT4B cell lines. Both cell lines were transfected with scrambled (SC) or p53 siRNA followed by EVO (8 µM) treatment for 24 h. Expression of p53 and internal control α-tubulin (TUB) protein was examined by Western blotting using specific antibodies. The intensity of each p53 band was examined by a densitometric analysis (Image J) and multiples of the control was calculated from triplicate groups as the mean ± SD. D p53 siRNA inhibited increases in the hypodiploid cell ratio and G2/M percentage in EVO-treated SW1736 cells but not KAT4B cells. As described in A, the ratio of hypodiploid cells and G2/M percentage were examined by a flow cytometric analysis. Each data point was calculated from triplicate groups, and data are shown as the mean ± SD. *p < 0.05 denotes a significant difference between indicated groups