Figure 5.
Q promotes the proteasome-mediated degradation of c-FLIPL. Western blotting revealed that Q decreases c-FLIPL expression in (A) BT-20 and MCF-7 cells in a dose-dependent manner. (B) BT-20 and MCF-7 cells were treated with a proteasome inhibitor MG132 alone and in combination with Q for 72 hours, and the cotreatment of MG132 and Q recovered c-FLIPL protein expression in breast cancer. Co-IP was performed on (C) BT-20 and (D) MCF-7 cells treated in the presence and absence of 50 µM Q for 72 hours. Q enhanced the ubiquitination of c-FLIPL in breast cancer. Blots were also probed for c-FLIPL to confirm that the Co-IP was properly executed. Co-IP indicates co-immunoprecipitation; Q, quercetin.