FIGURE 4.

Silencing of the EP1 receptor in MG63 cells affected the levels of apoptotic molecules. MG63 cells were transfected with EP1R-siRNA. After transfection (48 hours), the cells were exposed to PGE₂ (5 µM) for 48 hours. The proteins in cytoplasmic and mitochondrial lysates were extracted and assayed by Western blotting. Each sample was prepared in triplicate and the experiment was repeated three times. All bar graphs represent the mean ± SD. **p vs. siRNA control (Con). A significant increase in the level of Bax, cytoplasmic cyt c, and cleaved caspase-3, caspase-8 and caspase-9 was observed in EP1R-siRNA-transfected MG63 cells compared to the cells transfected with siRNA control. By contrast, the protein expression of Bcl-2 and mitochondrial cyt c was downregulated by EP1 silencing. c-cyt: Cytoplasmic cytochrome c; M-cyt: Mitochondrial cytochrome c; clea: cleaved; VDAC: Voltage-dependent anion channel; EP1R-siRNA: siRNA targeting the EP1 receptor; siRNA control: Non-silencing irrelevant RNA duplex.