Research Paper Volume 11, Issue 2 pp 771—782

Figure 5. EF24 downregulates the expression of the Bcl-2 anti-apoptotic family proteins in a proteasome-dependent manner. (A) Expression of Bcl-xl, Mcl-1 and Bcl-2 in WI-38 non-senescent cells (NCs) and IR-induced senescent cells (IR-SCs) after incubation with indicated concentrations of EF24 for 72 h. Protein levels were determined by western blots, and β‐actin was used as a loading control. (B-D) Quantification of Bcl-xl (B), Mcl-1(C) and Bcl-2 (D) protein expression in WI-38 NCs and IR‐SCs after treatment with indicated concentrations of EF24 for 72 h. Data are represented as mean ± SEM of three independent assays. *P < 0.05. **P < 0.01. (E-G) The mRNA levels of BCL-XL (F), MCL-1 (G) and BCL-2 (H) in WI-38 NCs and IR‐SCs after 72 h incubation with indicated concentrations of EF24. Results were normalized as fold change in mRNA expression compared to vehicle-treated control cells. Data are represented as mean ± SEM from three independent experiments. (H) Proteasome inhibition with MG132 blocks the effect of EF24 on Bcl-xl, Mcl-1, and Bcl-2 expression in WI-38 NC and IR‐SC cells. Cells were pretreated with 1 µM MG132 for 1 h, followed by treatment with indicated concentrations of EF24 for 72 h.