HDAC6-IN-11 (Compound 9) is a selective HDAC6 inhibitor with an IC50 value of 20.7 nM, demonstrating over 300-fold selectivity against other isoforms [1], and exhibits anti-proliferative activities against cancer cells.

HDAC6-IN-11 treatment, at concentrations ranging from 0.44-6.68 μM over 48 hours, exhibits anti-proliferative effects on A549 and HCT116 cells, reducing their proliferation rates with half-maximal inhibitory concentrations (GI50) of 3.2 μM for A549 cells and 1.82 μM for HCT116 cells, respectively [1]. Additionally, exposure to HDAC6-IN-11 across a broader concentration span of 0-20 μM for the same duration enhances the acetylation of H3 and tubulin in HCT116 cells, demonstrating a dose-dependent elevation in the acetylation levels of these proteins and notably increasing acetylated tubulin [1].