Tubastatin A (Tubastatin A BASE) is an effective and specific HDAC6 inhibitor (IC50: 15 nM, in a cell-free assay). Its selectivity is 1000-fold against all the other isozymes except HDAC8.

HDAC6:15 nM

与对照组相比,Tubastatin A 可使PCNA阳性细胞的量显著降低(34% vs 65%).在同基因大鼠原位胆管癌模型中,Tubastatin A（10 mg/kg）降低瘤重与肝重和体重（分别为5和5.6倍）的比值.在给弗氏完全佐剂诱导的动物炎症模型中,Tubastat A（30 mg/kg,i.p.）对鼠爪体积有显著抑制作用.Tubastat A（30 mg/kg,i.p.）处理胶原诱导型关节炎DBA1小鼠的爪子组织,使临床评分（70％）和IL-6表达显著降低.

Tubastatin A（5 μM）剂量依赖性地使神经元细胞免于同型半胱氨酸诱导的死亡,10 μM时可完全避免。 Tubastatin A（10 μM）对组蛋白乙酰化有轻微诱导作用。作用于胆管癌细胞系时,Tubastatin A（10 μM）促使乙酰化α-tubulin水平增加和初级纤毛表达的恢复,初级纤毛表达的恢复与Hedgehog、MAPK信号通路下调、细胞增殖率（平均50％）和浸润（40％）减少相关。作用于脂多糖刺激的人类 THP-1巨噬细胞时,Tubastatin A明显抑制TNF-α和IL-6（IC50：272/712 nM）。作用于小鼠Raw 264.7巨噬细胞时,Tubastatin A剂量依赖性抑制一氧化氮分泌（IC50：4.2 μM）。

HDAC enzymatic assays: Tubastatin A is dissolved and diluted in assay buffer (50 mM HEPES, pH 7.4, 100 mM KCl, 0.001% Tween-20, 0.05% BSA, and 20 μM tris(2-carboxyethyl)phosphine) to 6-fold of the final concentration. HDAC enzymes are diluted to 1.5-fold of the final concentration in assay buffer and pre-incubated with Tubastatin A for 10 minutes before the addition of the substrate. The amount of FTS (HDAC1, HDAC2, HDAC3, and HDAC6) or MAZ-1675 (HDAC4, HDAC5, HDAC7, HDAC8, and HDAC9) used for each enzyme is equal to the Michaelis constant (Km), as determined by a titration curve. FTS or MAZ-1675 is diluted in assay buffer to 6-fold the final concentration with 0.3 μM sequencing grade trypsin. The substrate/trypsin mix is added to the enzyme/compound mix and the plate is shaken for 60 seconds and then placed into a SpectraMax M5 microtiter plate reader. The enzymatic reaction is monitored for release of 7-amino-4-methoxy-coumarin over 30 minutes, after deacetylation of the lysine side chain in the peptide substrate, and the linear rate of the reaction is calculated.

Anchorage-independent growth is assessed by growing cells in soft agar. About 25,000 cells suspended in 0.4% agar in culture media are layered over a 1% agar layer in a 6-well plate. Media are added twice a week and pictures are taken after 21 days of incubation. The number and size of colonies are analyzed using the Gel-Pro software.(Only for Reference)