Inhibitor Expert (Inhibitors, Compound Libraries)



Technical Data

Molecular Weight 721.86 Storage powder


in solvent
CAS No. 537049-40-4 Synonyms N/A
Chemical Name N1-(4-((2R,4R,6S)-4-((4,5-diphenyloxazol-2-ylthio)methyl)-6-(4-(hydroxymethyl)phenyl)-1,3-dioxan-2-yl)phenyl)-N8-hydroxyoctanediamide
Solubility (25°C) * In vitro DMSO 100 mg/mL (138.53 mM)
Water Insoluble
Ethanol Insoluble
In vivo 2% DMSO+30% PEG 300+5% Tween 80+ddH2O 10mg/mL
* <1 mg/ml means slightly soluble or insoluble.
* Please note that Selleck tests the solubility of all compounds in-house, and the actual solubility may differ slightly from published values. This is normal and is due to slight batch-to-batch variations.

Biological Activity

Description Tubacin is a highly potent and selective, reversible, cell-permeable HDAC6 inhibitor with an IC50 of 4 nM in a cell-free assay, approximately 350-fold selectivity over HDAC1.
HDAC6 [1]
(Cell-free assay)
4 nM
In vitro Tubacin, without directly stabilizing microtubules, induces an increase in α-tubulin acetylation with EC50 of 2.5 μM in A549 cells. Tubacin inhibits HDAC6-mediated α-tubulin deacetylation, and inhibits the migration of both wild-type and HDAC6-overexpressing cells. [2] Tubacin, in combination with paclitaxel, synergistically enhances tubulin acetylation. [3] Tubacin significantly inhibits both drug-sensitive and drug–resistant MM cell growth with IC50 of 5–20 μM, and induces cell apoptosis by activation of caspases. [4]
In vivo In chick embryos, inhibition of HDAC6 activity by Tubacin reduces the formation of new blood vessels in matrigel/nylon mesh. In angioreactors implanted in mice, Tubacin also impairs the formation of new blood vessels. [5]
Features The first known selective inhibitor of α-tubulin deacetylation. 

Protocol (Only for Reference)

Kinase Assay:


Enzyme Inhibition Assay Enzyme inhibition assays are performed using the Reaction Biology HDAC Spectrum platform. The HDAC1, 2, 4, 5, 6, 7, 8, 9, 10, and 11 assays used isolated recombinant human protein; HDAC3/NcoR2 complex is used for the HDAC3 assay. Substrate for HDAC1, 2, 3, 6, 10, and 11 assays is a fluorogenic peptide from p53 residues 379-382 (RHKKAc); substrate for HDAC8 is fluorogenic diacyl peptide based on residues 379-382 of p53 (RHKAcKAc). Acetyl-Lys(trifluoroacetyl)-AMC substrate is used for HDAC4, 5, 7, and 9 assays. Compounds are dissolved in DMSO and tested in 10-dose IC50 mode with 3-fold serial dilution starting at 30 μM. Control Compound Trichostatin A (TSA) is tested in a 10-dose IC50 with 3-fold serial dilution starting at 5 μM. IC50 values are extracted by curve-fitting the dose/response slopes.
Cell Assay:


Cell lines Drug-sensitive (MM.1S, U266, INA-6, and RPMI8226) and drug-resistant (RPMI-LR5 and RPMI-Dox40) MM cell lines
Concentrations ~20 μM
Incubation Time 72 hours

The inhibitory effect of bortezomib and/or tubacin on MM cell growth is assessed by measuring 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) dye absorbance. All experiments are performed in quadruplicate.

Animal Study:


Animal Models Athymic nude mice implanted with angioreactors
Formulation DMSO
Dosages --
Administration Tubacin is filled in semiclosed angioreactors, and then implanted into the mice.


Customer Product Validation

Data from [Data independently produced by , , Nat Biotechnol, 2015, 33(4): 415-23 ]

Verification of Hdac6 deletion in knockout MEFs. Expression of HDAC6 and acetylation of tubulin were analyzed by immunoblotting.

Data from [Data independently produced by , , Oncogene, 2016, 35(18):2333-44]

Inhibition of HDAC6 by tubacin induced the acetylation and membrane translocation of wild-type PTEN, but not K163R mutant. U-87 MG or NCl-H1650 cells were transfected with EGFP-PTEN or EGFP-PTEN-K163R for 24 h and then treated with tubacin for 24 h. *P<0.01.

Tubacin has been referenced in publications.



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Chemical Structure

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