pIC50: 6.1 (BRD4), 6.3 (BRD2), 6.6 (BRD3)[1]

Following a 72-hour treatment with 1 μM dihydrochloride I-BET151, the majority of living cells were shown to be in the G0 phase, which was correlated with a dose- and time-dependent reduction in cell proliferation and an abrogation of bromodeoxyuridine incorporation[2]. The percentage of myeloma cells in the S/G2 phase is significantly reduced by I-BET151 dihydrochloride (100 nM; 72 hours) in a dose- and time-dependent manner[2].

I-BET151 dihydrochloride exhibits good oral systemic exposure, leading to good oral bioavailability, and poor blood clearance in rats (~20% liver blood flow). In the dog, there is high clearance (around 95% liver blood flow). The dog has a limited systemic exposure, which leads to a poor oral bioavailability of 16%. While the low intrinsic clearances in rat and mouse (mouse IVC 1.6 mL/min/g; CLb 8 mL/min/kg) coincide with lower in vivo blood clearances in these species, the high blood clearance in dogs is closely correlated with the high intrinsic clearance seen in dog microsomes and hepatocytes. I-BET151 dihydrochloride was examined in the mini-pig as a possible second species for toxicological study because of the dog's low systemic exposure, which was noted to have low clearance (~32% liver blood flow) and good bioavailability (65%)[1]. Compared to mice treated with vehicle, mice treated with I-BET151 dihydrochloride (30 mg/kg; ip; daily for 21 days) had myeloma tumors that were four to five times smaller and the rate of tumor size doubling was much lower[2].

Binding activity was assessed in BRD2, BRD3 and BRD4 fluorescence anisotropy (FP) assays as previously described [J. Med. Chem., 54 (2011), p. 3827]. Analogues of the isoxazoloquinolines competed with the FP ligand for binding to the bromodomains with sub-micromolar IC50’s, as shown in Table 1. A 1.8 Å resolution X-ray crystal structure of compound 1 was obtained by soaking into crystals of the BRD2 N-terminal bromodomain,6 revealing its binding mode (Fig. 1A)[1].

Cell Viability Assay[2]
Cell Types: H929 cells
Tested Concentrations: 1 μM
Incubation Duration: 72 hrs (hours)
Experimental Results: Displays the majority of live cells resided in the G0 phase and commensurate with a dose- and time-dependent decrease in cell proliferation and abrogation of bromodeoxyuridine incorporation.

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Cell Proliferation Assay[2]
Cell Types: H929 cells
Tested Concentrations: 100 nM
Incubation Duration: 72 hrs (hours)
Experimental Results: Caused a significant dose- and time-dependent decrease in the proportion of myeloma cells in S/ G2 phase.

Animal/Disease Models: Mice (model of subcutaneous (sc)myeloma)[2]
Doses: 50 mg/kg
Route of Administration: Ip; daily for 21 days
Experimental Results: diminished rate of tumor size doubling than vehicle-treated mice.

[1]. Identification of a novel series of BET family bromodomain inhibitors: Binding mode and profile of I-BET151 (GSK1210151A). Bioorg Med Chem Lett. 2012 Apr 15;22(8):2968-72.

[2]. Potent antimyeloma activity of the novel bromodomain inhibitors I-BET151 and I-BET762. Blood. 2014 Jan 30;123(5):697-705.

A novel series of quinoline isoxazole BET family bromodomain inhibitors are discussed. Crystallography is used to illustrate binding modes and rationalize their SAR. One member, I-BET151 (GSK1210151A), shows good oral bioavailability in both the rat and minipig as well as demonstrating efficient suppression of bacterial induced inflammation and sepsis in a murine in vivo endotoxaemia model.[1]

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The bromodomain and extraterminal (BET) protein BRD2-4 inhibitors hold therapeutic promise in preclinical models of hematologic malignancies. However, translation of these data to molecules suitable for clinical development has yet to be accomplished. Herein we expand the mechanistic understanding of BET inhibitors in multiple myeloma by using the chemical probe molecule I-BET151. I-BET151 induces apoptosis and exerts strong antiproliferative effect in vitro and in vivo. This is associated with contrasting effects on oncogenic MYC and HEXIM1, an inhibitor of the transcriptional activator P-TEFb. I-BET151 causes transcriptional repression of MYC and MYC-dependent programs by abrogating recruitment to the chromatin of the P-TEFb component CDK9 in a BRD2-4-dependent manner. In contrast, transcriptional upregulation of HEXIM1 is BRD2-4 independent. Finally, preclinical studies show that I-BET762 has a favorable pharmacologic profile as an oral agent and that it inhibits myeloma cell proliferation, resulting in survival advantage in a systemic myeloma xenograft model. These data provide a strong rationale for extending the clinical testing of the novel antimyeloma agent I-BET762 and reveal insights into biologic pathways required for myeloma cell proliferation.[2]

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Ankylosing spondylitis (AS) is characterized by osteoclastogenesis and inflammatory bone resorption. The present study aimed to investigate the effect of bromodomain and extra-terminal domain (BET) protein inhibitor I-BET151 on AS process. A total of 38 AS Chinese patients were recruited and a further 38 sex- and age-matched healthy participants were selected as control. The Bath AS Function Index and Bath AS Disease Activity Index were assessed in AS patients and levels of erythrocyte sedimentation rate and C-reactive protein were measured in AS and healthy groups. Serum from AS patients was used to induce MG63 osteoblasts and BET inhibitor I-BET151 at concentrations of 50, 100 and 200 ng/ml used for treatment of the cells. A HLA-B27/β2m transgenic AS Lewis rat model was established and treated with 30 mg/kg I-BET151 for 5 weeks. Levels of receptor activator of nuclear factor-κB ligand (RANKL), osteoprotegerin (OPG), matrix metalloproteinase (MMP)3, and MMP9 were measured using ELISA in vivo and additionally detected with western blotting and polymerase chain reaction in vitro. The levels of RANKL, OPG, MMP3 and MMP9 were upregulated in AS serum, AS serum treated MG63 cells and HLA-B27/β2m transgenic AS rats. Conversely, levels of RANKL, OPG, MMP3 and MMP9 were significantly inhibited in cells or animals treated with I-BET151. Overall, the results of the present study demonstrated that BET inhibitor I-BET151 suppresses levels of RANKL, OPG, MMP3 and MMP9 in AS in vivo and in vitro. I-BET151 may exhibit the potential to be used as a therapeutic in the treatment of AS patients.[3]

C23H23CL2N5O3

488.37

487.117

1883545-47-8

I-BET151;1300031-49-5

121513850

Typically exists as solids

UFLKDZBLUNJNJS-FFXKMJQXSA-N

3

6

4

33

665

1

[C@@H](C1N=CC=CC=1)(N1C(NC2C=NC3=CC(C4=C(ON=C4C)C)=C(OC)C=C3C1=2)=O)C.Cl

UFLKDZBLUNJNJS-FFXKMJQXSA-N

InChI=1S/C23H21N5O3.2ClH/c1-12-21(14(3)31-27-12)16-9-18-15(10-20(16)30-4)22-19(11-25-18)26-23(29)28(22)13(2)17-7-5-6-8-24-17;;/h5-11,13H,1-4H3,(H,26,29);2*1H/t13-;;/m1../s1

7-(3,5-dimethyl-1,2-oxazol-4-yl)-8-methoxy-1-[(1R)-1-pyridin-2-ylethyl]-3H-imidazo[4,5-c]quinolin-2-one;dihydrochloride

I-BET 151 dihydrochloride; 1883545-47-8; I-BET151Dihydrochloride; I-BET151 (dihydrochloride); 7-(3,5-dimethyl-1,2-oxazol-4-yl)-8-methoxy-1-[(1R)-1-pyridin-2-ylethyl]-3H-imidazo[4,5-c]quinolin-2-one;dihydrochloride;

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

May dissolve in DMSO (in most cases), if not, try other solvents such as H2O, Ethanol, or DMF with a minute amount of products to avoid loss of samples

Note: Listed below are some common formulations that may be used to formulate products with low water solubility (e.g. < 1 mg/mL), you may test these formulations using a minute amount of products to avoid loss of samples.

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Injection Formulation 1: DMSO : Tween 80： Saline = 10 : 5 : 85 (i.e. 100 μL DMSO stock solution → 50 μL Tween 80 → 850 μL Saline)
*Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH ₂ O to obtain a clear solution.
Injection Formulation 2: DMSO : PEG300 ：Tween 80 : Saline = 10 : 40 : 5 : 45 (i.e. 100 μL DMSO → 400 μLPEG300 → 50 μL Tween 80 → 450 μL Saline)
Injection Formulation 3: DMSO : Corn oil = 10 : 90 (i.e. 100 μL DMSO → 900 μL Corn oil)
Example: Take the Injection Formulation 3 (DMSO : Corn oil = 10 : 90) as an example, if 1 mL of 2.5 mg/mL working solution is to be prepared, you can take 100 μL 25 mg/mL DMSO stock solution and add to 900 μL corn oil, mix well to obtain a clear or suspension solution (2.5 mg/mL, ready for use in animals).

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Injection Formulation 4: DMSO : 20% SBE-β-CD in saline = 10 : 90 [i.e. 100 μL DMSO → 900 μL (20% SBE-β-CD in saline)]
*Preparation of 20% SBE-β-CD in Saline (4°C，1 week): Dissolve 2 g SBE-β-CD in 10 mL saline to obtain a clear solution.
Injection Formulation 5: 2-Hydroxypropyl-β-cyclodextrin : Saline = 50 : 50 (i.e. 500 μL 2-Hydroxypropyl-β-cyclodextrin → 500 μL Saline)
Injection Formulation 6: DMSO : PEG300 : castor oil : Saline = 5 : 10 : 20 : 65 (i.e. 50 μL DMSO → 100 μLPEG300 → 200 μL castor oil → 650 μL Saline)
Injection Formulation 7: Ethanol : Cremophor : Saline = 10： 10 : 80 (i.e. 100 μL Ethanol → 100 μL Cremophor → 800 μL Saline)
Injection Formulation 8: Dissolve in Cremophor/Ethanol (50 : 50), then diluted by Saline
Injection Formulation 9: EtOH : Corn oil = 10 : 90 (i.e. 100 μL EtOH → 900 μL Corn oil)
Injection Formulation 10: EtOH : PEG300：Tween 80 : Saline = 10 : 40 : 5 : 45 (i.e. 100 μL EtOH → 400 μLPEG300 → 50 μL Tween 80 → 450 μL Saline)

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Oral Formulation 1: Suspend in 0.5% CMC Na (carboxymethylcellulose sodium)
Oral Formulation 2: Suspend in 0.5% Carboxymethyl cellulose
Example: Take the Oral Formulation 1 (Suspend in 0.5% CMC Na) as an example, if 100 mL of 2.5 mg/mL working solution is to be prepared, you can first prepare 0.5% CMC Na solution by measuring 0.5 g CMC Na and dissolve it in 100 mL ddH2O to obtain a clear solution; then add 250 mg of the product to 100 mL 0.5% CMC Na solution, to make the suspension solution (2.5 mg/mL, ready for use in animals).

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Oral Formulation 3: Dissolved in PEG400
Oral Formulation 4: Suspend in 0.2% Carboxymethyl cellulose
Oral Formulation 5: Dissolve in 0.25% Tween 80 and 0.5% Carboxymethyl cellulose
Oral Formulation 6: Mixing with food powders

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Note: Please be aware that the above formulations are for reference only. InvivoChem strongly recommends customers to read literature methods/protocols carefully before determining which formulation you should use for in vivo studies, as different compounds have different solubility properties and have to be formulated differently.

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 (Please use freshly prepared in vivo formulations for optimal results.)