Figure 2.

Effect of KPE on cell-cycle arrest. Hs68 cells were pretreated with KPE (1–10 μg/ml) or resveratrol (10 μM) for 24 h. After 2 h of H₂O₂ exposure, the cells were cultured for an additional 24 h. (a, b) mRNA and protein levels of cell-cycle inhibitors (p16, p21, p53, and pRb) were investigated via RT-PCR and western blotting, respectively. (c) mRNA expression of cell-cycle activators, E2F1 and E2F2, was investigated via RT-PCR. Equal loading of mRNA and protein was verified based on GAPDH and α-tubulin levels, respectively.