3.7. Western blot analysis
HEK293 cells were plated in 6-well plates at a density of 5 × 105 cells/well and grown at 37 °C. Cells were treated with compounds at a final concentration of 20 μM for 24 h. Then, cells were harvested, lysed, centrifuged. The supernatants were utilized for protein analysis and western blot analysis. The total protein concentration was determined using a Bradford Protein Assay Kit. Protein samples were denatured, and final stored at −80 °C for western blotting. Equal amounts of protein (30 mg) from cell lysates were loaded onto a 10% SDS-polyacrylamide gel and separated by electrophoresis. β-actin served as an internal control. Then, the separated proteins were electrophoretically transferred to a 0.45 μm PVDF membrane. The transferred PVDF membranes were incubated with anti-SIRT1 primary antibodies (1:1000) at 4 °C overnight. Bound antibodies were detected using a horseradish peroxidase-linked secondary antibody.
Statistical analysis: All results were confirmed from a minimum of three independent experiments on replicate samples. Data are represented as the mean ± standard deviation (SD). Statistical significances were evaluated by the t-test. Data were considered significant at P < 0.05.