*2.9. SIRT1 Expression Assay*

SIRT1 levels were measured by using the Human SIRT1 ELISA kit in SaOS-2 cells, seeded in 12-well plates. Cell were solubilized in Cell Extraction Bu ffer and centrifuged at 18,000× *g* for 20 min at 4 ◦C according to manufacturer's instructions. Data, normalized on total protein content, were expressed as percentages of control levels.
