Cat. No.: HY-13032B

Molibresib besylate

(Synonyms: GSK 525762C; I-BET 762 besylate)

23 Cited Publications

Customer Review

Based on 23 publication(s) in Google Scholar

Molibresib besylate (GSK 525762C; I-BET 762 besylate) is an orally active pan-BET inhibitor that targets and binds to BRD2, BRD3, BRD4 and BRDT. By competitively occupying acetylated lysine binding sites, Molibresib besylate disrupts the interaction between BET proteins and chromatin, thereby effectively inhibiting MYC expression and target gene transcription. Molibresib besylate exhibits broad antiproliferative activity, which not only inhibits cancer cell growth and induces growth arrest, but also downregulates mitosis-related genes and upregulates the level of p-ERK1/2. When combined with MEK inhibitors, Molibresib besylate shows a significant synergistic effect, reduces tumor burden in mouse models of leukemia, modulates the immune microenvironment and prolongs survival. Molibresib besylate is widely applicable to research related to acute myeloid leukemia, multiple myeloma, triple-negative breast cancer, small-cell lung cancer and various advanced refractory solid tumors.

For research use only. We do not sell to patients.

Purity: 97.04%
CAS No.: 1895049-20-3
Formula: C₂₈H₂₈ClN₅O₅S
Molecular Weight:582.07

Storage:

4°C, sealed storage, away from moisture

* In solvent : -80°C, 6 months; -20°C, 1 month (sealed storage, away from moisture)

Molibresib besylate Chemical Structure

CAS No.: 1895049-20-3

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Fluorescent Dye

Strong Fluorescence Signal / Multi-Disciplinary Applications / High Fluorescence Specificity

Biological Activity
- Description
- IC₅₀ & Target
- In Vitro
- In Vivo
Chemical Information
Publications (23)
Solvent & Solubility
- In Vitro
- In Vivo
Purity & Documentation
References
Help & FAQs
Bioz

Biological Activity

Description

IC₅₀ & Target

IC50: 32.5-42.5 nM (BET)^[1]

All Epigenetic Reader Domain Isoforms :

All ERK Isoforms :

In Vitro

Molibresib (besylate) (10-500 nM; 7 days, single agent; 0.05-1.5 μM; 7 days, in combination with trametinib) alone inhibits primary Nras^G12D/+;Asxl1^-/- AML cell proliferation in vitro, and in combination with trametinib exerts synergistic anti-proliferative effects on these cells^[1].
Molibresib (besylate) (500 nM; 24-96 h) down-regulates MYC signatures and transiently down-regulates mitotic genes in RKO colorectal cancer cells, and combined treatment with trametinib results in sustained, robust down-regulation of mitotic, E2F, and apoptotic signatures that is greater than either single agent^[2].
Molibresib (besylate) (500 nM; 1-6 days) induces transient G1 arrest in RKO colorectal cancer cells and modest G1 arrest in BxPC-3 pancreatic cancer cells, and combined treatment with trametinib results in sustained G1 arrest in RKO cells and cell death in BxPC-3 cells^[2].
Molibresib (besylate) (100 nM to 1 μM; 1-6 days) up-regulates p-ERK1/2 levels in RPMI-8226 multiple myeloma, NCI-H510 small cell lung carcinoma, and NCI-H526 small cell lung carcinoma cells, and this up-regulation is reversed by co-treatment with MEK inhibitors^[2].
Molibresib (besylate) (500 nM (RPMI-8226), 1 μM (NCI-H510); 96 h) up-regulates ERK activation-associated genes in RPMI-8226 multiple myeloma and NCI-H510 small cell lung carcinoma cells, and this up-regulation is reversed by co-treatment with MEK inhibitors^[2].

MedChemExpress (MCE) has not independently confirmed the accuracy of these methods. They are for reference only.

Cell Cycle Analysis^[2]

Cell Line:

RKO (BRAFmut, NF1mut CRC) cells, BxPC-3 (KRASmut pancreatic cancer) cells
Concentration:

500 nM
Incubation Time:

1 day (cell cycle analysis); 6 days (cell cycle analysis)
Result:

Induced substantial G1 arrest in RKO cells at 1 day, which diminished by 6 days.
Induced modest G1 arrest in BxPC-3 cells at 6 days.
Resulted in sustained G1 arrest in RKO cells (with a greater proportion of cells in G1 at 6 days than at 1 day) when combined with trametinib.
Caused substantial sub-G1 accumulation (indicative of cell death) in BxPC-3 cells at 6 days when combined with trametinib.

Western Blot Analysis^[2]

Cell Line:

RPMI-8226 (KRASmut MM) cells, NCI-H510 (NF1mut SCLC) cells, NCI-H526 (SCLC) cells
Concentration:

250 nM, 500 nM, 1 μM (RPMI-8226); 100 nM, 1 μM (NCI-H510); 500 nM, 100 nM, 1 μM (NCI-H526)
Incubation Time:

4 days (RPMI-8226); 3 days (NCI-H510); 1 day, 6 days, 3 days (NCI-H526)
Result:

Increased p-ERK1/2 levels in RPMI-8226 cells after 4 days of single-agent treatment.
Increased p-ERK1/2 levels in NCI-H510 cells after 3 days of single-agent treatment.
Increased p-ERK1/2 levels in NCI-H526 cells after 1 and 6 days of single-agent treatment.
Reversed the Molibresib (besylate)-induced up-regulation of p-ERK1/2 when co-treated with MEK inhibitors (trametinib in RPMI-8226; PD0325901 in NCI-H510 and NCI-H526).

Real Time qPCR^[2]

Cell Line:

RPMI-8226 (KRASmut MM) cells, NCI-H510 (NF1mut SCLC) cells
Concentration:

500 nM (RPMI-8226); 1 μM (NCI-H510)
Incubation Time:

96 h
Result:

Up-regulated ERK activation-associated genes (DUSP4, DUSP6, SPRED1, SPRED2, EGR1, ETV5, SPRY4, SPRY2) in RPMI-8226 cells with single-agent treatment.
Up-regulated ERK activation-associated genes (DUSP4, DUSP6, SPRED1, SPRED2, EGR1, ETV5, SPRY4, SPRY2) in NCI-H510 cells with single-agent treatment.
Down-regulated ERK activation-associated genes compared to Molibresib (besylate) monotherapy when co-treated with MEK inhibitors (trametinib in RPMI-8226; PD0325901 in NCI-H510).

In Vivo

Combination of Molibresib besylate and Trametinib (HY-10999) reduces leukemia burden, reverses the immunosuppressive microenvironment, enhances the cytotoxicity of CD8⁺ T cells, and significantly prolongs survival in a mouse model of Nras^G12D/+;Asxl1^-/- acute myeloid leukemia^[1].
Combination therapy with Molibresib besylate and Trametinib significantly prolongs survival in a human CMML xenograft mouse model harboring concurrent RAS and ASXL1 mutations^[1].
Combination treatment with Molibresib besylate (15 mg/kg; p.o.; once daily) and Trametinib (1 mg/kg; p.o.; once daily) delays tumor growth in female NCr nu/nu mice inoculated with RKO colorectal cancer xenografts and MDA-MB-231 triple-negative breast cancer xenografts, respectively, and the combined effect is stronger than that of Molibresib besylate alone^[2].
Combination treatment with Molibresib besylate (25 mg/kg; p.o.; once daily) and Trametinib (1 mg/kg; p.o.; once daily) delays tumor growth in female CB.17 SCID mice inoculated with RPMI-8226 multiple myeloma xenografts, and the combined effect is stronger than that of Molibresib besylate alone^[2].

MedChemExpress (MCE) has not independently confirmed the accuracy of these methods. They are for reference only.

Animal Model:

NCr nu/nu mice with Colorectal cancer (female, 10 or 11 weeks old, implanted with RKO cells for xenograft modeling)^[2]
Dosage:

15 mg/kg (in combination with trametinib 1 mg/kg)
Administration:

p.o.; once daily
Result:

Produced significantly greater tumor growth delay, with statistically significant difference in time to tumor endpoint.

Animal Model:

NCr nu/nu mice with Triple-negative breast cancer (female, 10 or 11 weeks old, implanted with MDA-MB-231 cells for xenograft modeling)^[2]
Dosage:

15 mg/kg (in combination with trametinib 1 mg/kg)
Administration:

p.o.; once daily
Result:

Produced significantly greater tumor growth delay, with statistically significant difference in time to tumor endpoint.

Animal Model:

CB.17 SCID mice with Multiple myeloma (female, 12 weeks old, implanted with RPMI-8226 cells for xenograft modeling)^[2]
Dosage:

25 mg/kg (in combination with trametinib 0.1 mg/kg)
Administration:

p.o.; once daily
Result:

Produced significantly greater tumor growth delay, with statistically significant difference in time to tumor endpoint.

Chemical Information

CAS No. 1895049-20-3
Appearance Solid
Molecular Weight 582.07
Formula C₂₈H₂₈ClN₅O₅S
Color White to off-white
SMILES

ClC1=CC=C(C2=N[C@@H](CC(NCC)=O)C3=NN=C(C)N3C4=CC=C(OC)C=C24)C=C1.O=S(C5=CC=CC=C5)(O)=O
Synonyms

GSK 525762C; I-BET 762 besylate
Shipping

Room temperature in continental US; may vary elsewhere.
Storage

4°C, sealed storage, away from moisture

* In solvent : -80°C, 6 months; -20°C, 1 month (sealed storage, away from moisture)

Publications (23)

All Flow CytometryBio/Physico-chemical AssayRT-PCRWB

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Journal Impact Factor

Nat Med

Intrinsic BET inhibitor resistance in SPOP-mutated prostate cancer is mediated by BET protein stabilization and AKT-mTORC1 activation. [Abstract]

2017 Sep;23(9):1055-1062. PMID: 28805822

Molibresib besylate purchased from MedChemExpress. Usage Cited in: Nat Med. 2017 Sep;23(9):1055-1062. [Abstract]

Western blot of WCL of C4-2 cells treated with vehicle (DMSO) or different doses of JQ1 or i-BET for 24 h. Actin is used as a loading control.
Cell

BET inhibition blocks inflammation-induced cardiac dysfunction and SARS-CoV-2 infection. [Abstract]

2021 Apr 15;184(8):2167-2182.e22. PMID: 33811809
Cell Metab

Lactate controls cancer stemness and plasticity through epigenetic regulation. [Abstract]

2025 Apr 1;37(4):903-919.e10. PMID: 39933514
Nat Commun

Epigenetic-based differentiation therapy for Acute Myeloid Leukemia. [Abstract]

2024 Jul 2;15(1):5570. PMID: 38956053

Molibresib besylate purchased from MedChemExpress. Usage Cited in: Nat Commun. 2024 Jul 2;15(1):5570. [Abstract]

HL-60 cells were treated daily with 25% GI₅₀ concentrations of CM-444, CM-1758, Molibresib, and JQ1, or CM-444 or CM-1758 in combination with Molibresib or JQ1, for 48 hours. The cell differentiation experiment was performed by detecting CD11b by flow cytometry.

Molibresib besylate purchased from MedChemExpress. Usage Cited in: Nat Commun. 2024 Jul 2;15(1):5570. [Abstract]

ML-2 cells were treated daily with 25% GI₅₀ concentrations of CM-444, CM-1758, Molibresib, and JQ1, or CM-444 or CM-1758 in combination with Molibresib or JQ1, for 48 hours. The cell differentiation experiment was performed by detecting CD11b by flow cytometry.

Molibresib besylate purchased from MedChemExpress. Usage Cited in: Nat Commun. 2024 Jul 2;15(1):5570. [Abstract]

q-PCR results of GATA2, PU.1, SCL and CEBPA in HL-60 cells after daily treatment with 25% GI50 concentrations of CM-444, CM-1758, Molibresib, JQ1, and CM-444 or CM-1758 in combination with Molibresib or JQ1 for 48 hours.

Molibresib besylate purchased from MedChemExpress. Usage Cited in: Nat Commun. 2024 Jul 2;15(1):5570. [Abstract]

q-PCR results of GATA2, PU.1, SCL and CEBPA in ML-2 cells after daily treatment with 25% GI50 concentrations of CM-444, CM-1758, Molibresib, JQ1, and CM-444 or CM-1758 in combination with Molibresib or JQ1 for 48 hours.
Sci Adv

Patient-tailored design for selective co-inhibition of leukemic cell subpopulations. [Abstract]

2021 Feb 19;7(8):eabe4038. PMID: 33608276

Molibresib besylate purchased from MedChemExpress. Usage Cited in: Sci Adv. 2021 Feb 19;7(8):eabe4038. [Abstract]

Comparison of expression levels of molibresib targets BRD2, BRD3 and BRD4 between leukemic and nonleukemic cells of AML1.
J Exp Med

Convergent roles of ATF3 and CSL in chromatin control of cancer-associated fibroblast activation. [Abstract]

2017 Aug 7;214(8):2349-2368. PMID: 28684431
Cancer Lett

The combination of BET and PARP inhibitors is synergistic in models of cholangiocarcinoma. [Abstract]

2020 Jan 1;468:48-58. PMID: 31605774
Proc Natl Acad Sci U S A

MGMT-activated DUB3 stabilizes MCL1 and drives chemoresistance in ovarian cancer. [Abstract]

2019 Feb 19;116(8):2961-2966. PMID: 30718431
Cell Syst

A Library of Phosphoproteomic and Chromatin Signatures for Characterizing Cellular Responses to Drug Perturbations. [Abstract]

2018 Apr 25;6(4):424-443.e7. PMID: 29655704
Blood Adv

Triple combination of BET plus PI3K and NF-κB inhibitors exhibit synergistic activity in adult T-cell leukemia/lymphoma. [Abstract]

2022 Apr 12;6(7):2346-2360. PMID: 35030628
J Med Chem

Novel Pyrrolopyridone Bromodomain and Extra-Terminal Motif (BET) Inhibitors Effective in Endocrine-Resistant ER+ Breast Cancer with Acquired Resistance to Fulvestrant and Palbociclib. [Abstract]

2020 Jul 9;63(13):7186-7210. PMID: 32453591
Elife

Cohesin mutations are synthetic lethal with stimulation of WNT signaling. [Abstract]

2020 Dec 7;9:e61405. PMID: 33284104
Atherosclerosis

RVX-208, a BET-inhibitor for treating atherosclerotic cardiovascular disease, raises ApoA-I/HDL and represses pathways that contribute to cardiovascular disease. [Abstract]

2016 Apr:247:48-57. PMID: 26868508
Commun Biol

Three-dimensional CRISPR screening reveals epigenetic interaction with anti-angiogenic therapy. [Abstract]

2021 Jul 15;4(1):878. PMID: 34267311
Harvard University

2026.
bioRxiv

2026 May 7.
bioRxiv

2026 Jan 9.
bioRxiv

BRD2 Upregulation as a Pan-Cancer Adaptive Resistance Mechanism to BET Inhibition. [Abstract]

2025 Sep 3:2025.08.30.673282. PMID: 40949948
bioRxiv

AI-assisted Drug Re-purposing for Human Liver Fibrosis. [Abstract]

2025 May 4:2025.04.29.651320. PMID: 40654780
SSRN

2024 Apr 6.
Patent

US20220016130A1.
Patent

US20180263995A1.
Oncotarget

BET bromodomain-mediated interaction between ERG and BRD4 promotes prostate cancer cell invasion. [Abstract]

2016 Jun 21;7(25):38319-38332. PMID: 27223260

Molibresib besylate purchased from MedChemExpress. Usage Cited in: Oncotarget. 2016 Jun 21;7(25):38319-38332. [Abstract]

iBET762 partially disrupts the interaction between full-length ERG and BRD4 (A), and between T1-E4 ERG and BRD4 (B).

Solvent & Solubility

In Vitro:

DMSO : 25 mg/mL (42.95 mM; Need ultrasonic; Hygroscopic DMSO has a significant impact on the solubility of product, please use newly opened DMSO)

View the Complete Stock Solution Preparation Table

Preparing Stock Solutions

View the Complete Stock Solution Preparation Table

Concentration Solvent Mass

1 mg

5 mg

10 mg

Concentration

Solvent

Mass

1 mM

1.7180 mL

8.5900 mL

17.1801 mL

5 mM

0.3436 mL

1.7180 mL

3.4360 mL

10 mM

0.1718 mL

0.8590 mL

1.7180 mL

Please refer to the solubility information to select the appropriate solvent. Once prepared, please aliquot and store the solution to prevent product inactivation from repeated freeze-thaw cycles.

Storage method and period of stock solution: -80°C, 6 months; -20°C, 1 month (sealed storage, away from moisture). When stored at -80°C, please use it within 6 months. When stored at -20°C, please use it within 1 month.

Molarity Calculator

Mass (g) = Concentration (mol/L) × Volume (L) × Molecular Weight (g/mol)

Mass Mass

Concentration Concentration

Volume Volume

Molecular Weight Molecular Weight

Dilution Calculator

Concentration _(start) × Volume _(start) = Concentration _(final) × Volume _(final)

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In Vivo:

Select the appropriate dissolution method based on your experimental animal and administration route.

Stock Solution Working Solution

For the following dissolution methods, please ensure to first prepare a clear stock solution using an In Vitro approach and then sequentially add co-solvents:
To ensure reliable experimental results, the clarified stock solution can be appropriately stored based on storage conditions. As for the working solution for In Vivo experiments, it is recommended to prepare freshly and use it on the same day.
The percentages shown for the solvents indicate their volumetric ratio in the final prepared solution. If precipitation or phase separation occurs during preparation, heat and/or sonication can be used to aid dissolution.

Protocol 1

Add each solvent one by one: 10% DMSO 40% PEG300 5% Tween-80 45% Saline

Solubility: ≥ 2.67 mg/mL (4.59 mM); Clear solution

This protocol yields a clear solution of ≥ 2.67 mg/mL (saturation unknown).

Taking 1 mL working solution as an example, add 100 μL DMSO stock solution (26.7 mg/mL) to 400 μL PEG300, and mix evenly; then add 50 μL Tween-80 and mix evenly; then add 450 μL Saline to adjust the volume to 1 mL.

Protocol 2

Add each solvent one by one: 10% DMSO 90% (20% SBE-β-CD in Saline)

Solubility: ≥ 2.67 mg/mL (4.59 mM); Clear solution

This protocol yields a clear solution of ≥ 2.67 mg/mL (saturation unknown).

Taking 1 mL working solution as an example, add 100 μL DMSO stock solution (26.7 mg/mL) to 900 μL 20% SBE-β-CD in Saline, and mix evenly.

Protocol 3

Add each solvent one by one: 10% DMSO 90% Corn Oil

Solubility: ≥ 2.67 mg/mL (4.59 mM); Clear solution

This protocol yields a clear solution of ≥ 2.67 mg/mL (saturation unknown). If the continuous dosing period exceeds half a month, please choose this protocol carefully.

Taking 1 mL working solution as an example, add 100 μL DMSO stock solution (26.7 mg/mL) to 900 μL Corn oil, and mix evenly.

In Vivo Dissolution Calculator

Please enter the basic information of animal experiments:

Dosage Dosage
mg/kg
Animal Weight (Per Animal) Animal Weight (Per Animal)
g
Dosing Volume (Per Animal) Dosing Volume (Per Animal)
μL
Number of Animals Number of Animals

Recommended: Prepare an additional quantity of animals to account for potential losses during experiments.

Recommended: Prepare an additional quantity of animals to account for potential losses during experiments.

Please enter your animal formula composition:

%
DMSO +

Recommended: Keep the proportion of DMSO in working solution below 2% if your animal is weak.
%
+
+
%
Tween-80 + +
%
Saline +

The co-solvents required include: DMSO, . All of co-solvents are available by MedChemExpress (MCE). , Tween 80. All of co-solvents are available by MedChemExpress (MCE).

Working solution concentration: 0.22 mg/mL

Purity & Documentation

Select Batch:

Purity: 99.98%

Assay: 99.98%

ee.: 99.98%

Data Sheet (291 KB)
SDS (252 KB)
- English - EN (252 KB)
- Français - FR (252 KB)
- Deutsch - DE (252 KB)
- Norwegian - NO (252 KB)
- Español - ES (252 KB)
- Swedish - SV (252 KB)
- Italian - IT (252 KB)
- Korean - KR (252 KB)
- Portuguese - PT (252 KB)
COA (2659 KB)
Elemental Analysis Report (2659 KB)
HNMR (2659 KB)
CNMR (2659 KB)
RP-HPLC (2659 KB)
NP-HPLC (2659 KB)
MS (2659 KB)
LCMS (2659 KB)
IR (2659 KB)
GC (2659 KB)
OR (2659 KB)
SDS-PAGE (2659 KB)
SEC-HPLC (2659 KB)
Other Report (2659 KB)
Handling Instructions (2659 KB)

References

[1]. You X, et al. Asxl1 loss cooperates with oncogenic Nras in mice to reprogram the immune microenvironment and drive leukemic transformation. Blood. 2022;139(7):1066-1079. [Content Brief]

[2]. Wyce A, et al. MEK inhibitors overcome resistance to BET inhibition across a number of solid and hematologic cancers. Oncogenesis. 2018;7(4):35. Published 2018 Apr 20. [Content Brief]

[3]. Kulka LAM, et al. Impact of HDAC Inhibitors on Protein Quality Control Systems: Consequences for Precision Medicine in Malignant Disease. Front Cell Dev Biol. 2020;8:425. Published 2020 Jun 3. [Content Brief]

Help & FAQs

How should lyophilized recombinant proteins be reconstituted and stored?

1. Before opening the cap, centrifuge the vial at 13000 rpm for 20-30 seconds. This step will ensure that any lyophilized powder that may have adhered to the cap or walls is collected at the bottom of the vial, minimizing the risk of product loss.

Complete Stock Solution Preparation Table

Optional Solvent	Concentration Solvent Mass	1 mg	5 mg	10 mg	25 mg
DMSO	1 mM	1.7180 mL	8.5900 mL	17.1801 mL	42.9502 mL
	5 mM	0.3436 mL	1.7180 mL	3.4360 mL	8.5900 mL
	10 mM	0.1718 mL	0.8590 mL	1.7180 mL	4.2950 mL
	15 mM	0.1145 mL	0.5727 mL	1.1453 mL	2.8633 mL
	20 mM	0.0859 mL	0.4295 mL	0.8590 mL	2.1475 mL
	25 mM	0.0687 mL	0.3436 mL	0.6872 mL	1.7180 mL
	30 mM	0.0573 mL	0.2863 mL	0.5727 mL	1.4317 mL
	40 mM	0.0430 mL	0.2148 mL	0.4295 mL	1.0738 mL

Keywords

Molibresib besylate

23 Cited Publications

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Molibresib besylate

Epigenetics Compound Library

Immunology/Inflammation Compound Library

MAPK Compound Library

Stem Cell Signaling Compound Library

Histone Modification Research Compound Library

Anti-Cancer Compound Library

Anti-Aging Compound Library

Reprogramming Compound Library

Oxygen Sensing Compound Library

Orally Active Compound Library

Glutamine Metabolism Compound Library

Neuroprotective Compound Library

Anti-Breast Cancer Compound Library

Anti-Lung Cancer Compound Library

Anti-Pancreatic Cancer Compound Library

Anti-Blood Cancer Compound Library

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Pain-Related Compound Library

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Multi-Target Compound Library

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MCE Bioactive Compound Library

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Cell Proliferation Compound Library

High-Throughput Bioactive Compound Library

RNA Binding Bioactive Compound Library

Lactylation Compound Library

Publications Citing Use of MedChemExpress (MCE) Molibresib besylate

All Epigenetic Reader Domain Isoforms

All ERK Isoforms

Biological Activity

Chemical Information

Publications (23)

Solvent & Solubility

Purity & Documentation

References

Help & FAQs

Complete Stock Solution Preparation Table

Molibresib besylate Related Classifications

Cat. No.: HY-13032B