Structure-Guided Discovery of Subtype Selective SIRT6 Inhibitors with a β-Carboline Skeleton for the Treatment of Breast Cancer

SIRT6 promotes the progression of breast cancer by inducing drug resistance by reinforcing DNA damage repair mechanisms. This study utilized a combination of high-throughput virtual screening and FLUOR DE LYS assays. Hit 14 which features a novel β-carboline skeleton as a potent SIRT6 inhibitor was found. Subsequent structure-guided optimization led to the synthesis of 60 3,6,9-position modified derivatives based on the differences analysis of SIRTs family proteins. Of which, 10d inhibited the deacetylase activity of SIRT6, with an IC₅₀ of 5.81 μM and more than 27 times subtype selectivity. Phe64, Met157, and Ser56 were identified as the key residues. Moreover, 10d suppressed breast cancer cell proliferation, migration, invasion, and induced apoptosis in MCF-7 cells by disrupting the DNA damage repair pathway. Additionally, 10d demonstrated a safe and effective antibreast cancer effect in vivo, presenting a promising strategy for the treatment of breast cancer by targeting SIRT6.