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Catalog No.S7152

46 publications

C646 Chemical Structure

CAS No. 328968-36-1

C646 is an inhibitor for histone acetyltransferase, and inhibits p300 with a Ki of 400 nM in a cell-free assay. Preferentially selective for p300 versus other acetyltransferases. C646 induces cell cycle arrest, apoptosis and autophagy.

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Selleck's C646 has been cited by 46 publications

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Choose Selective Histone Acetyltransferase Inhibitors

Biological Activity

Description C646 is an inhibitor for histone acetyltransferase, and inhibits p300 with a Ki of 400 nM in a cell-free assay. Preferentially selective for p300 versus other acetyltransferases. C646 induces cell cycle arrest, apoptosis and autophagy.
Features Extensively used as a pharmacologic probe in cancer cells. Potential use for prostate and lung cancers.
p300/CBP [1]
(Cell-free assay)
400 nM(Ki)
In vitro

C646 is an inhibitor for histone acetyltransferase, inhibits p300 with a Ki of 400 nM and is selective versus other acetyltransferases. C646 produces 86% inhibition of p300 in vitro at 10 μM. C646 is a classical reversible p300 inhibitor. C646 treatment (25μM) reduces histone H3 and H4 acetylation levels and abrogates TSA-induced acetylation in cells. [1] C646 (20μM) induces apoptosis in androgen-sensitive and castration-resistant prostate cancer cell lines by interfering with AR and NF-kB pathways. [2] C646 blocks dynamic acetylation of H3K4me3 globally in mouse and fly cells, and locally across the promoter and start-site of inducible genes in the mouse, thereby disrupting RNA polymerase II association and the activation of these genes. [3]

Cell Data
Cell Lines Assay Type Concentration Incubation Time Formulation Activity Description PMID
NE-4C cells NWTJVWhxTnWwY4Tpc44h[XO|YYm= M3rrTlAuPSEQvF2= MknPbIlocCCpbIXjc5NmKGmwZIXj[YQhcW6lcnXhd4V{KG:oIFi0T|Vi[yCjbnSgTFRMPS96L{GyM|E3[WNibHX2[Yx{KGmwIF7FMVREKGOnbHzzJIFz\SCrbnjpZol1\WRiYomgZYRlcXSrb36gc4Yh[SC|ZXzlZ5RqfmViQ1LQM5A{ODBiaX7obYJqfG:{IFO2OFYhcW5iYTDkc5NmNWSncHXu[IVvfCC5YYmgLIZzd21iMDD0c{A2KM7:TTm= NIDX[Ic{ODFzNEO0Oi=>
SH-SY5Y M37LNGZ2dmO2aX;uJIF{e2G7 MkX4NlDDqM7:TR?= MXGyOEBp NV3IdmhuS29vdILlZZRu\W62IIfpeIghOjBiwsXNJGM3PDZic4XwdJJme3OnZDD0bIUh\W[oZXP0JI9nKFSVQTD0doVifG2nboSgc44hSWyxeEG1JI1TVkFiZYjwdoV{e2mxbjDifUA3PS55JR?= NFP6NGEzQTJ|NUCzOi=>
GES-1 M3rVSGZ2dmO2aX;uJIF{e2G7 NEP3TmcyOCEQvF2= NEK4ZVU3KGh? M2XJSmM3PDZidILlZZRu\W62IIPp[45q\mmlYX70cJkhemWmdXPl[EB1cGVibHX2[Yx{KG:oIHjpd5RwdmViSEOgZYNmfHmuYYTpc44hcW5iYn;0bEBISyClZXzsd{BidmRibn;ycYFtKGejc4TybYMh\XCrdHjlcIlidCClZXzsd{ApWDxyLkC1LS=> NGTp[IszQTB5NUe5OS=>
SGC-7901 MofySpVv[3Srb36gZZN{[Xl? NEW2RnYyOCEQvF2= M2i0OVYhcA>? MVHDOlQ3KHS{ZXH0cYVvfCC|aXfubYZq[2GwdHz5JJJm\HWlZXSgeIhmKGyndnXsd{Bw\iCqaYP0c45mKEh|IHHj[ZR6dGG2aX;uJIlvKGKxdHigS2Mh[2WubIOgZY5lKG6xcn3hcEBo[XO2cnnjJIVxcXSqZXzpZYwh[2WubIOgLHA9OC5yNTm= NFHINW8zQTB5NUe5OS=>
MKN45 MY\GeY5kfGmxbjDhd5NigQ>? MWOxNEDPxE1? MmjSOkBp MXjDOlQ3KHS{ZXH0cYVvfCC|aXfubYZq[2GwdHz5JJJm\HWlZXSgeIhmKGyndnXsd{Bw\iCqaYP0c45mKEh|IHHj[ZR6dGG2aX;uJIlvKGKxdHigS2Mh[2WubIOgZY5lKG6xcn3hcEBo[XO2cnnjJIVxcXSqZXzpZYwh[2WubIOgLHA9OC5yNTm= MlTzNlkxPzV5OUW=
MGC-803 MljCSpVv[3Srb36gZZN{[Xl? M{\BWVExKM7:TR?= M3XKRlYhcA>? MVfDOlQ3KHS{ZXH0cYVvfCC|aXfubYZq[2GwdHz5JJJm\HWlZXSgeIhmKGyndnXsd{Bw\iCqaYP0c45mKEh|IHHj[ZR6dGG2aX;uJIlvKGKxdHigS2Mh[2WubIOgZY5lKG6xcn3hcEBo[XO2cnnjJIVxcXSqZXzpZYwh[2WubIOgLHA9OC5yNTm= MYOyPVA4PTd7NR?=
BGC-823 NXjqNnJxTnWwY4Tpc44h[XO|YYm= NVfXd3oyOTBizszN MnuxOkBp MnS0R|Y1PiC2cnXheI1mdnRic3nncolncWOjboTsfUBz\WS3Y3XkJJRp\SCuZY\lcJMhd2ZiaHnzeI9v\SCKMzDhZ4V1gWyjdHnvckBqdiCkb4ToJGdEKGOnbHzzJIFv\CCwb4LtZYwh\2G|dILpZ{BmeGm2aHXsbYFtKGOnbHzzJEhRRDBwMEWp NY\6dIJKOjlyN{W3PVU>
KATO III M4XEcmZ2dmO2aX;uJIF{e2G7 MUOxNEDPxE1? MnG5OkBp MnnpR|Y1PiC2cnXheI1mdnRic3nncolncWOjboTsfUBz\WS3Y3XkJJRp\SCuZY\lcJMhd2ZiaHnzeI9v\SCKMzDhZ4V1gWyjdHnvckBqdiCkb4ToJGdEKGOnbHzzJIFv\CCwb4LtZYwh\2G|dILpZ{BmeGm2aHXsbYFtKGOnbHzzJEhRRDBwMEWp M4C4ZVI6ODd3N{m1
Raw246.7 NFTDNGJHfW6ldHnvckBie3OjeR?= M17WV|EtKDVuIEGwMEAyPSxiMkCsJFI2NCCxcjCzNEDPxE1? M4K2U|E3KGh? M3HVc5Jme3WudIOgbY4he2mpbnnmbYNidnRiaX7obYJqfGmxbjDv[kBNWFNiYX7kJGlHVs7|IHnu[JVk\WRiTl[t{tpDKHC{b33veIVzKGGldHn2bZR6KGG2IEG1JO69VSCxcjDobYdp\XJiY3;uZ4VvfHKjdHnvcpM> M2Lrc|I3PzF6NUi2
WM35 M1PMeGZ2dmO2aX;uJIF{e2G7 MmnpNVAh|ryPIHHu[EAzOCEQvF2= MYeyOEBp NHTiVFViKGSxc3Wt[IVx\W6mZX70JIRm[3KnYYPlJIlvKHSqZTDwdo91\WmwIHzleoVteyCxZjDjfYNtcW6|IFGgZY5lKEVuIHHjZ49ueGGwaXXkJIJ6KGGwIHnuZ5Jm[XOnZDDlfJBz\XO|aX;uJI9nKHB3MzDhcoQhcXS|IHTve45{fHKnYX2g[YZn\WO2b4KgdFIy NYrpWFN1OjN4OUiwO|E>
1205Lu MUfGeY5kfGmxbjDhd5NigQ>? MWSxNEDPxE1iYX7kJFIxKM7:TR?= NELsW2YzPCCq MYnhJIRwe2VvZHXw[Y5l\W62IHTlZ5Jm[XOnIHnuJJRp\SCycn;0[YlvKGyndnXsd{Bw\iCleXPsbY5{KEFiYX7kJGUtKGGlY3;tdIFvcWWmIHL5JIFvKGmwY4LlZZNm\CCneIDy[ZN{cW:wIH;mJJA2OyCjbnSgbZR{KGSxd37zeJJm[W1iZX\m[YN1d3JicEKx NGjlc2wzOzZ7OEC3NS=>
WM983B MoH0SpVv[3Srb36gZZN{[Xl? MlzwNVAh|ryPIHHu[EAzOCEQvF2= NWOyWGR1OjRiaB?= Mn\IZUBld3OnLXTldIVv\GWwdDDk[YNz\WG|ZTDpckB1cGVicILveIVqdiCuZY\lcJMhd2ZiY4njcIlveyCDIHHu[EBGNCCjY3PvcZBidmmnZDDifUBidiCrbnPy[YF{\WRiZYjwdoV{e2mxbjDv[kBxPTNiYX7kJIl1eyCmb4fud5Rz\WGvIHXm[oVkfG:{IICyNS=> NH;qOGwzOzZ7OEC3NS=>
Kasumi-1 NEWwdW5Iem:5dHigbY5pcWKrdHnvckBie3OjeR?= NF:5OIEyOCxiMkWgZY5lKDVyIN88US=> NILIdWUxNCB{NDygOFgtKDd{IHi= NIC4boFk\WyudXzhdkBoem:5dHigZY5lKGOxbH;ufUBnd3KvYYTpc44hf2W{ZTDkdoFu[XSrY3HscJkhe3WycILld5Nm\CC3cH;uJGM3PDZidILlZZRu\W62Lh?= NYLaW29vOjN|OUC1N|Y>
SKNO-1 NInRSJRIem:5dHigbY5pcWKrdHnvckBie3OjeR?= MljiNVAtKDJ3IHHu[EA2OCEQvF2= NFTVTJQxNCB{NDygOFgtKDd{IHi= MoH1Z4VtdHWuYYKg[5Jwf3SqIHHu[EBkd2yxbomg[o9zdWG2aX;uJJdmemViZILhcYF1cWOjbHz5JJN2eHC{ZYPz[YQhfXCxbjDDOlQ3KHS{ZXH0cYVvfC5? NGm2Uo8zOzN7MEWzOi=>

... Click to View More Cell Line Experimental Data

Methods Test Index PMID
Western blot

PubMed: 27322077     

The effect of C646 on p300 HAT activity. Cells were treated with C646 at 30 uM for MIAPaCa2 and 40 uM for Panc1 for 48 hours and then cell lysates were applied for western blotting to evaluate acetylated H3K27 as a surrogate of p300 HAT activity. C646 inhibited p300 HAT activity.

Cyclin A1/2 / Cyclin E2 / p53 / p21 ; 

PubMed: 23698071     

Western blot analyses on WM35, 1205Lu and WM983B cells. Lanes 1-4 represent 24 h of treatment with 0.2% DMSO, 10 μM C646, 20 μM C646 and 20 μM C37, respectively. 


PubMed: 28630312     

HCC2429 cells were treated with DMSO or with 20, 30, or 40 μM C646 for 6 h. Whole-cell lysates were analyzed on SDS/PAGE and immunoblotted with indicated antibodies.

27322077 23698071 28630312
BRD4 / p300 ; 

PubMed: 28630312     

HCC2429 cells were treated with 20 μM C646 for 1 h, 1 μM (+)-JQ1 for 1 h, or 5 mM HMBA for 12 h. Untreated control cells and treated cells were fixed and immunostained with BRD4 C and p300 antibodies and were counterstained with DAPI. (Scale bars: 10 μm) 

In vivo C646 infused into the ILPFC immediately after weak extinction training enhances the consolidation of fear extinction memory. [4] C646 attenuates mechanical allodynia and thermal hyperalgesia, accompanied by a suppressed COX-2 expression, in the spinal cord. [5]


Kinase Assay:[1]
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Radioactive assay:

IC50 values for the putative p300 HAT inhibitors are determined using the direct radioactive assay described above. Reactions are performed in 20 mM HEPES (pH 7.9), and contained 5 mM DTT, 80μM EDTA, 40μg/ml BSA, 100μM H4-15, and 5 nM p300. Putative inhibitors are added over a range of concentrations, with DMSO concentration kept constant (<5%). Reactions are incubated at 30°C for 10 min, then initiated with addition of a 1:1 mixture of 12C-acetyl-CoA and 14C-acetyl-CoA to 20 mM. After 10 min at 30°C, reactions are quenched with 14% SDS (w/v). All concentrations are screened in duplicate. Gels are run, washed, dried, and exposed to a PhosphorImager plate, and production of Ac-H4-15 quantified to obtain IC50s.
Cell Research:[1]
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  • Cell lines: C3H10T1/2
  • Concentrations: ~25 μM
  • Incubation Time: 1 to 3 hr
  • Method: Histone acetylation assays in mouse cells. C3H10T1/2 mouse fibroblasts are grown in DMEM with 10% FCS at 37°C with 6% CO2. Confluent cultures are rendered quiescent in DMEM with 0.5% FCS for 18-20 hr prior to treatment. Cells are treated with the following compounds: TSA (10 ng/ml [33 nM]), C646 (25 μM), C37 (25 μM). Antibodies are used at the following concentrations: total H3 (1:10000; ab7834; Abcam); H4K12ac (1:2500; 06-761; Upstate). Rabbit anti-H3K9ac (1:10000) antibodies are generated in-house. Histones are isolated from cells by acid extraction, separated by SDS and acid-urea polyacrylamide gel electrophoresis and analyzed by western blotting.
    (Only for Reference)
Animal Research:[4]
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  • Animal Models: mouse
  • Dosages: 2×0.75 μl injection volume in each case, 1.5 μg, administered over 2 min
  • Administration: infusion into ILPFC
    (Only for Reference)

Solubility (25°C)

In vitro DMSO 13 mg/mL (29.18 mM)
Water Insoluble
Ethanol Insoluble
In vivo Add solvents to the product individually and in order(Data is from Selleck tests instead of citations):
5% DMSO+40% PEG 300+5%Tween 80+ddH2O
For best results, use promptly after mixing.

* 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 445.42


CAS No. 328968-36-1
Storage powder
in solvent
Synonyms N/A
Smiles CC1=CC(=C(C=C1C)[N+](=O)[O-])C2=CC=C(O2)C=C3C(=NN(C3=O)C4=CC=C(C=C4)C(=O)O)C

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% DMSO % % Tween 80 % ddH2O

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Tech Support

Answers to questions you may have can be found in the inhibitor handling instructions. Topics include how to prepare stock solutions, how to store inhibitors, and issues that need special attention for cell-based assays and animal experiments.

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Frequently Asked Questions

  • Question 1:

    I am planning to conduct IP studies in mice, any specific vehicle that you can recommend to me?

  • Answer:

    We found it can be dissolved in 5% DMSO+30% PEG 300+ddH2O at 1 mg/ml as a clear solution. It should be ok for i.p. injection.

Histone Acetyltransferase Signaling Pathway Map

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Cell Lines Assay Type Concentration Incubation Time Formulation Activity Description PMID