HDAC1-IN-5, a potent inhibitor of HDAC1 with an IC50 value of 15 nM, also exhibits inhibitory activity towards HDAC6 with an IC50 value of 20 nM. In cancer cells, HDAC1-IN-5 enhances the acetylation of both histone H3 and α-tubulin, leading to the activation of caspase 3 and induction of apoptosis. Additionally, HDAC1-IN-5 binds with DNA, causing chromatin damage. Furthermore, it demonstrated strong inhibitory activity against tumor growth in xenograft mice. [1]