SIRT2 and malignant colon neoplasm: Compound 1 inhibited Sirt1 with an IC50 value of 2.7 μM and demonstrated 8.5 and >300-fold selectivity for Sirt1 over Sirt2 and Sirt3; moreover, a concentration-dependent increase of p53 acetylation in the HCT116 colon cancer cell line suggested that Compound 1 effectively inhibited cellular Sirt1 [181].