Figure 6.

Capsaicin inhibits SIRT1 expression and enzymatic activity in A375 cells. A. Capsaicin significantly induced SIRT1 downregulation at the translational level analyzed by Western blotting and at the transcriptional level determined by RT-PCR. B. Capsaicin suppressed cellular SIRT1 activity analyzed by a SIRT1 Activity Assay Kit (Fluorometric) with control or capsaicin-exposed A375 cell lysates. Values (mean ± SDs) are from three independent experiments (***P<0.001). C. The lysates of A375 cells were immunoprecipitated with nonimmune IgG or an antibody against ULK1, and the bound proteins were detected by Western blotting with pan-acetylated lysine or ULK1 antibodies. D. A375 cells were exposed to different concentrations of capsaicin or ethanol for 24 hours. Aliquots of cell lysates were separated by SDS-PAGE and analyzed for protein expression by Western blotting. β-actin was used as an internal loading control to monitor for equal loading. Representative images are shown from at least three independent experiments.