Inhibitor Expert (Inhibitors, Compound Libraries)


Tacedinaline (CI994)

Technical Data

Molecular Weight 269.3 Storage powder


in solvent
CAS No. 112522-64-2 Synonyms PD-123654, GOE-5549, Acetyldinaline
Chemical Name Benzamide, 4-(acetylamino)-N-(2-aminophenyl)-
Solubility (25°C) * In vitro DMSO 54 mg/mL (200.51 mM)
Water Insoluble
Ethanol Insoluble
In vivo 5% DMSO+40% PEG 300+ddH2O 5mg/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 Tacedinaline (CI994) is a selective class I HDAC inhibitor with IC50 of 0.9, 0.9, 1.2, and >20 μM for human HDAC 1, 2, 3, and 8, respectively. Phase 3.
HDAC1 [1]
(Cell-free assay)
HDAC2 [1]
(Cell-free assay)
HDAC3 [1]
(Cell-free assay)
0.9 μM 0.9 μM 1.2 μM
In vitro CI-994 (< 160 mM) shows cytostatic effect with concomitant increase at G0/G1 phase, a reduction at S phase level and increased apoptosis in A-549 and LX-1 cells. [2] CI-994 inhibits growth of LNCaP cell with IC50 of 7.4 μM. [3] CI-994 exerts activity against several tumor cell lines with greater cytotoxicity against the solid tumors relative to both the leukemia and normal fibroblast cell lines. [4] CI-994 inhibits growth of rat leukemia BCLO cells with IC50 of 2.5 μM. [5]
In vivo CI-994 exerts demonstrated antitumor activity against several tumor models, including the chemo-resistant mouse pancreatic ductal carcinoma as well as the human prostate tumor model LNCaP. [4]

Protocol (Only for Reference)

Cell Assay:


Cell lines LNCaP cell lines
Concentrations 2.5 μM
Incubation Time 2-4 days

LNCaP cell lines are maintained in RPMI 1640 medium containing 10% fetal bovine serum, 1% penicillin and streptomycin, as the complete culture medium. Cells (2×104) are seeded in 24-well plates and incubated in a 5% CO2 incubator at 37 °C for 1 day. Cultures are treated with CI-994, alone and in combination on day 2 and 4. Cells are washed on day 2 and 4 and media are changed. Mitochondrial metabolism is measured as a marker for cell growth by adding 100 μL/well MTT (5 mg/mL in medium) with 2 hours incubation at 37 °C on Day 6. Crystals formed are dissolved in 500 μL of DMSO. The absorbance is determined using a microplate reader at 560 nm. The absorbance data are converted into cell proliferation percentage. Each assay is performed in triplicate.

Animal Study:


Animal Models human prostate tumor model LNCaP
Formulation 5% ethanol, 1% P.O.E. and 94% dH20
Dosages 535 mg/kg
Administration Administered via oral gavage


Customer Product Validation

Data from [Data independently produced by , , J Biol Chem, 2016, 291(14):7386-95]

A, 5×106 HeLa, A549, 293T, and H1299 cells were seeded in 10-cm cell culture dishes on day 0 and treated with dimethyl sulfoxide, 10 μM CI994, or 1 μM RGFP966 for 12 h. Cell lysates were collected for Western blotting analysis of Apaf-1 and -actin.

Data from [Data independently produced by , , Cell Oncol (Dordr), 2017, 40(3):263-279]

Apoptosis marker analysis. Daoy and D283 Med cells were exposed to various HDACi 24 h before total RNA samples were prepared for qRT-PCR. Daoy cells were exposed to DMSO, 25 nM TSA, 1 μM SAHA, 1.5 μM MS-275, 0.7 μM mocetinostat, 7 μM tacedinaline, 1.5 nM romidepsin and 2 μM parthenolide, respectively. D283 Med cells were exposed to DMSO, 40 nM TSA, 1.5 μM SAHA, 2 μM MS-275, 0.3 μM mocetinostat, 8 μM tacedinaline, 1 nM romidepsin and 4 μM parthenolide, respectively. Expression of the apoptosis markers BAX and BCL2, as well as the apoptotic BAX/BCL2 ratios, are shown. * p < 0.05; **p < 0.01.

Tacedinaline (CI994) has been referenced in publications.



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Chemical Structure

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