BH3I-1

BH3I-1 is a Bcl-2 family antagonist, which inhibits the binding of the Bak BH3 peptide to Bcl-xL with a Ki of 2.4±0.2 μM in FP assay. BH3I-1 has a Kd of 5.3 μM against the p53/MDM2 pair.

Signaling Pathways >> Apoptosis >> Bcl-2 Family

Signaling Pathways >> Apoptosis >> MDM-2/p53

Research Areas >> Cancer

Bcl-2

Bcl-xL

Bak

Bim

p53/mDM2:5.3 μM (Kd)

BH3I-1, while inhibiting its reported target Bcl-2/Bim and Bcl-xL/Bim, shows significant inhibition of both the p53/hDM2 and p300/Hif-1α interactions. This surprising promiscuity, displays by a well studied compound leads to further interrogate the p53/hDM2 interaction utilizing a standard fluorescence polarization (FP) assay with purified protein. The results from the FP assay validates the split-luciferase screen and demonstrates that BH3I-1 has a Kd=5.3 μM against the p53/mDM2 pair, which is comparable to its low micromolar potency reported for the BH3 family of receptors[2]. BH3I-1 inhibits interaction between the BH3 domain and Bcl-xL. NMR analyses reveal that BH3I-1 targets the BH3-binding pocket of Bcl-xL with a Ki of 7.8±0.9 μM[3].

Jurkat cells overexpressing Bcl-xL, FL 5.12 and FL 5.12/Bcl-xL cells (5×104 cells per well) are seeded into white 96-well plates and treated with various concentrations of the compounds (e.g., BH3I-1; 30 μM and 90 μM)for 48 h. For zVAD-FMK protection experiments, cells are preincubated with 100 μM zVAD-FMK for 1 h before the addition of chemicals. Cell viability is determined with an MTS assay with a Victor plate reader. For PI staining experiments, cells are grown in 24-well plates and then incubated with 2 μg/mL PI. Cell death is determined by FACS analysis in a FACSCalibur machine[3].

[1]. Wang L, et al. Development of dimeric modulators for anti-apoptotic Bcl-2 proteins. Bioorg Med Chem Lett. 2008 Jan 1;18(1):236-40.

[2]. Porter JR, et al. Profiling small molecule inhibitors against helix-receptor interactions: the Bcl-2 family inhibitor BH3I-1 potently inhibits p53/hDM2. Chem Commun (Camb). 2010 Nov 14;46(42):8020-2.

[3]. Degterev A, et al. Identification of small-molecule inhibitors of interaction between the BH3 domain and Bcl-xL. Nat Cell Biol. 2001 Feb;3(2):173-82.

Venetoclax (ABT-199) | ABT-263 | S63845 | ABT-737 | Pifithrin-α hydrobromide | RG7388 | Nutlin-3a | AMG232 | Obatoclax Mesylate | A-1210477 | A-1155463 | WEHI-539 hydrochloride | A-1331852 | Pifithrin-β (hydrobromide) | Stylomycin aminonucleoside