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Updated: Jun 12, 2026
Bimolecular Fluorescence Complementation
Published on: April 15, 2011
Development of a Fluorescence Polarization Assay for p300/CBP and Its Application Using a Direct-to-Biology Approach
Jiayin Liang1,2, Ziyi Li3,4, Lu Jin2
1Guangzhou University of Chinese Medicine, Guangdong 510006, China.
Abstract:
The histone acetyltransferases E1A binding protein of 300 kDa (p300) and its homologue cyclic AMP response element binding protein (CREB) binding protein (CBP) are potential targets for cancer treatment. However, no drugs targeting p300/CBP have yet been approved. Various bioassay methods have been developed to evaluate the inhibitory potency of the corresponding inhibitors. However, suitable assays for high-throughput screening (HTS) of novel inhibitors targeting the p300/CBP bromodomain are lacking. To address this shortcoming, we developed a fluorescence polarization (FP) assay. This employs a rationally designed strategy that exhibits excellent characteristics, making it suitable for the large-scale evaluation of compound bioactivity. To enable direct-to-biology application of this FP assay, we constructed an 840-compound library on microplates via the CuAAC reaction and performed in situ HTS. Using this platform, we rapidly identified a series of small molecules that target the p300 bromodomain and exhibit potent activity. Computational chemistry studies have provided insight into the binding mode of the inhibitors, while cellular studies and H3K27 acetylation levels demonstrate the favorable properties of these compounds against acute myeloid leukemia (AML). Overall, this platform demonstrates a multifunctional approach, integrating rational FP probe design with combinatorial chemistry. This closes a methodological gap in the rapid discovery of p300/CBP bromodomain inhibitors, providing a new paradigm for accelerating drug discovery.
Insights
Researchers developed a new fluorescence polarization assay for high-throughput screening of p300/CBP bromodomain inhibitors, accelerating the discovery of potential cancer therapeutics.
Area of Science:
- Biochemistry and Molecular Biology
- Medicinal Chemistry
- Cancer Research
Background:
- Histone acetyltransferases p300/CBP are crucial in cancer, making them attractive therapeutic targets.
- Existing assays lack suitability for high-throughput screening (HTS) of p300/CBP bromodomain inhibitors.
- A need exists for efficient methods to discover novel small molecules targeting p300/CBP.
Purpose of the Study:
- To develop a novel, high-throughput fluorescence polarization (FP) assay for screening p300/CBP bromodomain inhibitors.
- To integrate FP assay development with combinatorial chemistry for rapid compound library screening.
- To identify and characterize novel small molecule inhibitors of the p300 bromodomain.
Main Methods:
- Development of a rationally designed fluorescence polarization (FP) assay for p300/CBP bromodomain inhibition.
- Construction of an 840-compound library using click chemistry (CuAAC reaction) for in situ HTS.
- Application of computational chemistry for binding mode analysis and cellular studies to assess compound efficacy.
Main Results:
- Successful implementation of an FP assay suitable for large-scale compound bioactivity evaluation.
- Rapid identification of potent small molecule inhibitors targeting the p300 bromodomain via in situ HTS.
- Demonstration of favorable anti-acute myeloid leukemia (AML) properties and H3K27 acetylation modulation by identified compounds.
Conclusions:
- The developed FP assay platform effectively bridges the gap in discovering p300/CBP bromodomain inhibitors.
- This integrated approach of FP assay design and combinatorial chemistry accelerates drug discovery for cancer.
- The identified compounds show promise for targeting AML by modulating p300/CBP activity.
