For research use only.

Catalog No.S2244 Synonyms: HDAC-42

24 publications

AR-42 Chemical Structure

CAS No. 935881-37-1

AR-42 (HDAC-42) is an HDAC inhibitor with IC50 of 30 nM. Phase 1.

Selleck's AR-42 has been cited by 24 publications

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Biological Activity

Description AR-42 (HDAC-42) is an HDAC inhibitor with IC50 of 30 nM. Phase 1.
Features Greater potency relative to SAHA.
HDAC [1]
(Cell-free assay)
30 nM
In vitro

AR-42 treatment induces histone hyperacetylation and p21WAF/CIP1 overexpression, and inhibits the growth of DU-145 cells with IC50 of 0.11 μM. [1] HDAC42 is potent in suppressing the proliferation of U87MG and PC-3 cells, in part, because of its ability to down-regulate Akt signaling. [2] AR-42 inhibits the growth of PC-3 and LNCaP cells with IC50 of 0.48 μM and 0.3 μM, respectively. Compared to SAHA, AR-42 exhibits distinctly superior apoptogenic potency, and causes markedly greater decreases in phospho-Akt, Bcl-xL, and survivin in PC-3 cells. [3] AR-42 treatment induces growth inhibition, cell- cycle arrest, apoptosis, and activation of caspases-3/7 in malignant mast cell lines. AR-42 treatment induces down-regulation of Kit via inhibition of Kit transcription, disassociation between Kit and heat shock protein 90 (HSP90), and up-regulation of HSP70. AR-42 treatment down-regulates the expression of p-Akt, total Akt, phosphorylated STAT3/5 (pSTAT3/5), and total STAT3/5. [6] AR-42 potently inhibits the growth of JeKo-1, Raji, and 697 cells with IC50 of <0.61 μM. AR-42 also sensitizes CLL cells to TNF-Related Apoptosis Inducing Ligand (TRAIL), potentially through reduction of c-FLIP. [7] AR-42 treatment also induces autophagy through downregulation of Akt/mTOR signaling and inducing ER stress in hepatocellular carcinoma (HCC) cells. [8]

Methods Test Index PMID
Western blot
gp130 / p-STAT3 / STAT3 / p-AKT / AKT / p-MEK / MEK ; 

PubMed: 20824695     

U266 cells were treated for 24 hr with or without AR-42 and analyzed for the indicated protein by immunoblotting.

Cyclin D1 / p21 / p16 / Cyclin A / Cyclin B1 ; 

PubMed: 20824695     

AR-42 induces expression of p16 and p21 and reduces expression of cyclin D1. U266 cells were treated with 0.05% DMSO or AR-42 at the shown concentrations for 24 hr. Lysates were then prepared immediately and analyzed by Western blot for cyclin D1, p21, p16, cyclin A and cyclin B.

Act-H3 / Act-H3 / Act-tubulin ; 

PubMed: 20233974     

AR-42 treatment induces acetylation of histones and α-tubulin in malignant mast cells. P815, C2, and BR cell lines were treated with the indicated concentrations of AR-42 or 1μM 17-AAG and canine BMCMCs were treated with 1μM AR-42 or 17-AAG for 24 hours. Effects on the acetylation status of histones H3 and H4 and α-tubulin were determined by Western blotting.

p-Kit / Kit ; 

PubMed: 20233974     

P815, C2, and BR cells and canine BMCMCs were treated with either AR-42 or 17-AAG (1μM AR-42 and 17-AAG for BMCMCs) at the indicated concentrations for 24 hours. Effects on the expression of phosphorylated Kit and total Kit were determined by Western blot analysis. The top band represents the mature form and the bottom band the immature form of Kit. 

Notch1 / NICD / Nestin / Zeb-1 / BMI-1 ; 

PubMed: 26625202     

The expression levels of acetyl-histone H3 (Ac-H3), Notch1, NICD, and/or the downstream stemness markers nestin, Zeb-1, and BMI-1 in MDA-MB-231 after 72 h of treatment.

20824695 20233974 26625202
Growth inhibition assay
Cell viability; 

PubMed: 26993777     

Cells were treated with AR-42 and quantified via CCK-8 assay.

In vivo The growth of PC-3 tumor xenografts is suppressed by 52% and 67% after treatment with AR-42 at 25 mg/kg and 50 mg/kg, respectively, whereas SAHA at 50 mg/kg suppresses growth by 31%. In contrast to mice treated with SAHA, intratumoral levels of phospho-Akt and Bcl-xL are markedly reduced in AR-42 treated mice. [3] In the transgenic adenocarcinoma of the mouse prostate (TRAMP) model, administration of AR-42 not only decreases the severity of prostatic intraepithelial neoplasia (PIN) and completely prevents its progression to poorly differentiated carcinoma, but also shifts tumorigenesis to a more differentiated phenotype, suppressing absolute and relative urogenital tract weights by 86% and 85%, respectively. [5] AR-42 significantly reduces leukocyte counts, and prolongs survival in three separate mouse models of B-cell malignancy without evidence of toxicity. [7]


Kinase Assay:


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In vitro HDAC assay:

HDAC activity is analyzed by using an HDAC assay kit. This assay is based on the ability of DU-145 nuclear extract, which is rich in HDAC activity, to mediate the deacetylation of the biotinylated [3H]-acetyl histone H4 peptide that is bound to streptavidin agarose beads. The release of [3H]-acetate into the supernatant is measured to calculate the HDAC activity. Sodium butyrate (0.25-1 mM) is used as a positive control.
Cell Research:


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  • Cell lines: DU-145
  • Concentrations: Dissolved in DMSO, final concentrations ~2.5 μM
  • Incubation Time: 96 hours
  • Method:

    Cells are exposed to varous concentrations of AR-42 for 96 hours. The medium is removed and replaced by 150 μL of 0.5 mg/mL of MTT in RPMI 1640 medium, and the cells are incubated in the CO2 incubator at 37 °C for 2 hours. Supernatants are removed from the wells, and the reduced MTT dye is solubilized with 200 μL/well of DMSO. Absorbance is determined on a plate reader at 570 nm.

    (Only for Reference)
Animal Research:


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  • Animal Models: Intact male NCr athymic nude mice inoculated s.c. with PC-3 cells
  • Dosages: ~50 mg/kg/day
  • Administration: Orally
    (Only for Reference)

Solubility (25°C)

In vitro DMSO 63 mg/mL (201.69 mM)
Ethanol 63 mg/mL (201.69 mM)
Water Insoluble
In vivo Add solvents to the product individually and in order(Data is from Selleck tests instead of citations):
0.5% methylcellulose+0.2% Tween 80
For best results, use promptly after mixing.
30 mg/mL

* 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.

Chemical Information

Molecular Weight 312.36


CAS No. 935881-37-1
Storage powder
in solvent
Synonyms HDAC-42
Smiles CC(C)C(C1=CC=CC=C1)C(=O)NC2=CC=C(C=C2)C(=O)NO

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Clinical Trial Information

NCT Number Recruitment interventions Conditions Sponsor/Collaborators Start Date Phases
NCT02795819 Terminated Drug: AR-42|Drug: Pazopanib Renal Cell Carcinoma|Soft Tissue Sarcoma|Metastatic Disease Virginia Commonwealth University|National Cancer Institute (NCI) July 8 2016 Phase 1
NCT02282917 Active not recruiting Drug: AR-42 Vestibular Schwannoma|Meningioma|Acoustic Neuroma|Neurofibromatosis Type 2 Massachusetts Eye and Ear Infirmary|Johns Hopkins University|Mayo Clinic|Stanford University|Ohio State University|Nationwide Children''s Hospital September 2015 Early Phase 1

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Cell Lines Assay Type Concentration Incubation Time Formulation Activity Description PMID