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]

HDAC1-IN-5 (compound 4j) (0-50 μM; 48 h) exhibits strong inhibitory effects on HCT116, HeLa, HepG2, MC38, K562 and HEL [1]. HDAC1-IN-5 (0.16-1.5 μM; 48 h) induces apoptosis in a dose-dependent manner [1]. HDAC1-IN-5 (0.17-1.5 μM; 24 h or 48 h) induces downregulation of SPT16 and SSRP-1, induces the cleavage of caspase-3, and increases the expression of Acetyl-Histone H3 and Acetyl-α-tubulin [1]. Cell Proliferation Assay [1] Cell Line: HCT116, HeLa, HepG2, MC38, K562 and HEL Concentration: 0-50 μM Incubation Time: 48 h Result: Showed strong inhibitory effects on HCT116, HeLa, HepG2, MC38, K562 and HEL with IC 50 s of 0.47 μM, 0.78 μM, 1.4 μM, 0.43 μM, 0.91 μM and 0.28 μM, respectively. Apoptosis Analysis [1] Cell Line: HCT116 Concentration: 0.16 μM, 0.5 μM and 1.5 μM Incubation Time: 48 h Result: Induced apoptosis in a dose-dependent manner, and induced 38.5% at the concentration of 1.5 μM (both early and late apoptotic cells). Western Blot Analysis [1] Cell Line: HCT116 and MC38 Concentration: 0.17 μM, 0.5 μM and 1.5 μM Incubation Time: 24 h or 48 h Result: Induced downregulation of SPT16 and SSRP-1 in HCT116. Induced the cleavage of caspase-3 in HCT116 and MC38. Increased the expression of HDAC1, 2, 6 substrate Acetyl-Histone H3 and Acetyl-α-tubulin with a dose-dependent manner.

HDAC1-IN-5 (50 and 100 mg/kg; IP; every two days; for 16 days) significantly decreases the tumor volume and weight in MC38 xenograft mice [1]. Animal Model: C57BL/6 mice (6-10 weeks; 2×10 6 MC38 cells were injected subcutaneously into the right flank regions) [1] Dosage: 50 and 100 mg/kg Administration: IP; every two days; for 16 days Result: Significantly decreased the tumor volume and weight with tumor growth inhibition (TGI) of 66% at 50 mg/kg.