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.

This article discusses a series of novel quinoline isoxazol BET family bromodomain inhibitors. Their binding modes and structure-activity relationships were elucidated using crystallographic methods. One member, I-BET151 (GSK1210151A), showed good oral bioavailability in rats and miniature pigs and effectively inhibited bacterial-induced inflammation and sepsis in a mouse model of endotoxemia. [1]

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Inhibitors of the bromodomain and terminal domain (BET) protein BRD2-4 have shown therapeutic potential in preclinical models of hematologic malignancies. However, these data have not yet been translated into molecules suitable for clinical development. This article uses the chemical probe molecule I-BET151 to deepen our understanding of the mechanism of action of BET inhibitors in multiple myeloma. I-BET151 induces apoptosis and exerts a strong antiproliferative effect both in vitro and in vivo. This is related to the opposite effect of the oncogene MYC and the transcription activator P-TEFb inhibitor HEXIM1. I-BET151 inhibits the transcription of MYC and its dependent program by blocking the recruitment of P-TEFb component CDK9 to chromatin in a BRD2-4 dependent manner. In contrast, the transcriptional upregulation of HEXIM1 is independent of BRD2-4. Finally, preclinical studies have shown that I-BET762 has good pharmacological properties as an oral drug and can inhibit myeloma cell proliferation, thereby prolonging the survival of patients in a systemic myeloma xenograft model. These data provide a strong theoretical basis for expanding the clinical trials of the novel anti-myeloma drug I-BET762 and reveal the biological pathways required for myeloma cell proliferation. [2]

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Ankylosing spondylitis (AS) is characterized by osteoclastogenesis and inflammatory bone resorption. This study aimed to investigate the effect of the bromodomain and terminal domain (BET) protein inhibitor I-BET151 on the course of AS. A total of 38 Chinese AS patients were recruited and 38 sex- and age-matched healthy subjects were selected as the control group. The Bath AS functional index and Bath AS disease activity index were assessed in patients with ankylosing spondylitis (AS), and erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) levels were measured in both the AS group and healthy controls. MG63 osteoblasts were induced using serum from AS patients and treated with the BET inhibitor I-BET151 at concentrations of 50, 100, and 200 ng/ml. An HLA-B27/β2m transgenic AS Lewis rat model was established and treated with 30 mg/kg I-BET151 for 5 weeks. The levels of receptor activator of nuclear factor κB (RANKL), osteoprotegerin (OPG), matrix metalloproteinase (MMP) 3, and MMP9 were detected in vivo using ELISA, and further analyzed in vitro using Western blotting and PCR. Results showed significantly elevated levels of RANKL, OPG, MMP3, and MMP9 in AS serum, AS serum-treated MG63 cells, and HLA-B27/β2m transgenic AS rats. Conversely, in cells or animals treated with I-BET151, the levels of RANKL, OPG, MMP3, and MMP9 were significantly reduced. In summary, the results of this study indicate that the BET inhibitor I-BET151 can inhibit the expression of RANKL, OPG, MMP3, and MMP9 in AS both in vivo and in vitro. I-BET151 may have the potential to be used as a therapy for patients with ankylosing spondylitis. [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.)