HDAC8 14 μM (IC 50 ) HDAC1 >100 μM (IC 50 ) HDAC6 >100 μM (IC 50 )

Dose-limiting toxicities (DLTs) of 1-Naphthohydroxamic acid (compound 2; 0-40 mg/kg; intraperitoneal injection; daily; for 10 day; NMRI Foxn1 nude mice) include weight loss and signs of liver toxicity, as evidenced by elevated plasma liver enzymes and detection of necrotic areas on histological liver examination. 1-Naphthohydroxamic acid has the maximum tolerable doses at 50 mg/kg per day. At these concentrations, neither body weight nor blood parameters are critically changed. Pharmacokinetic studies after intraperitoneal administration of the inhibitors identified the half-life of 1-Naphthohydroxamic acid to be ~15 min, with a plasma peak concentration of ~30 μM. Animal Model: NMRI Foxn1 nude mice Dosage: 0 mg/kg, 50 mg/kg, 100mg/kg, 200 mg/kg, 300 mg/kg 400 mg/kg Administration: Intraperitoneal injection; daily; for 10 days Result: Dose-limiting toxicities (DLTs) included weight loss and signs of liver toxicity, as evidenced by elevated plasma liver enzymes and detection of necrotic areas on histological liver examination.

1-Naphthohydroxamic acid (compound 2; 20-40 µM; 0-144  hours; BE(2)-C, SK-N-BE(2) and SH-SY5Y cells) treatment reduces cell numbers in a concentration-dependent manner. 1-Naphthohydroxamic acid (compound 2) at concentrations in the range of its in vitro IC 50 against HDAC8 results in reduced cell density and outgrowth of neurite-like structures that stained positive for neurofilament.1-Naphthohydroxamic acid reduces the formation of clones in soft-agar concentration dependently. When either cell type (HeLa and HEK293 cells) is treated with 1-Naphthohydroxamic acid (compound 2; 0.8 µM, 4 µM, 20 µM or 100 µM), only tubulin becomes hyperacetylated. Cell Proliferation Assay Cell Line: BE(2)-C, SK-N-BE(2) and SH-SY5Y cells Concentration: 20 µM, 40 µM Incubation Time: 0 hours, 24 hours, 48 hours, 72 hours, 96 hours, and 144  hours Result: Reduced cell numbers in a concentration-dependent manner.

1-Naphthohydroxamic acid (Compound 2) 是一种有效的，选择性的 HDAC8 抑制剂，IC50 为 14 μM。1-Naphthohydroxamic acid 对 HDAC8 的选择性高于 I 类 HDAC1 和 II 类 HDAC6 (IC50 >100 μM)。1-Naphthohydroxamic acid 不会增加整体组蛋白 H4 的乙酰化，也不会降低总细胞内 HDAC 的活性。1-Naphthohydroxamic acid 可诱导微管蛋白乙酰化。