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Updated: May 3, 2026
Kinase Inhibitor Screening In Self-assembled Human Protein Microarrays
Published on: October 23, 2019
Development of a cell-based, high-throughput screening assay for ATM kinase inhibitors
Kexiao Guo1, Anang A Shelat, R Kiplin Guy
11Department of Oncology, St. Jude Children's Research Hospital, Memphis, TN, USA.
Abstract:
The ATM (ataxia-telangiectasia, mutated) protein kinase is a major regulator of cellular responses to DNA double-strand breaks (DSBs), DNA lesions that can be caused by ionizing irradiation (IR), oxidative damage, or exposure to certain chemical agents. In response to DSBs, the ATM kinase is activated and subsequently phosphorylates numerous downstream substrates, including p53, Chk2, BRCA1, and KAP1, which affect processes such as cell cycle progression and DNA repair. Numerous studies have demonstrated that loss of ATM function results in enhanced sensitivity to ionizing irradiation in clinically relevant dose ranges, suggesting that ATM kinase is an attractive therapeutic target for enhancing tumor cell kill with radiotherapy. Previously identified small-molecule ATM kinase inhibitors, such as CP466722 and Ku55933, were identified using in vitro kinase assays carried out with recombinant ATM kinase isolated from mammalian cells. Since it has not been feasible to express full-length recombinant ATM in bacterial or baculovirus systems, a robust in vitro screening tool has been lacking. We have developed a cell-based assay that is robust, straightforward, and sensitive. Using this high-throughput assay, we screened more than 7000 compounds and discovered additional small molecules that inhibit the ATM kinase and further validated these hits by secondary assays.
Insights
Researchers developed a new cell-based assay to screen for ATM kinase inhibitors. This assay identified new compounds that inhibit ATM, a key target for enhancing radiotherapy in cancer treatment.
Area of Science:
- Molecular Biology
- Biochemistry
- Oncology
Background:
- ATM (ataxia-telangiectasia, mutated) kinase regulates DNA double-strand break (DSB) responses.
- ATM activation affects cell cycle progression and DNA repair via substrates like p53, Chk2, BRCA1, and KAP1.
- Loss of ATM function increases sensitivity to ionizing radiation, positioning ATM as a therapeutic target for radiotherapy enhancement.
Purpose of the Study:
- To develop a robust, high-throughput cell-based assay for ATM kinase inhibitor screening.
- To identify novel small-molecule inhibitors of ATM kinase.
- To overcome limitations of previous in vitro assays due to difficulties in expressing full-length recombinant ATM.
Main Methods:
- Development of a sensitive, straightforward cell-based assay for ATM kinase activity.
- Screening of over 7000 compounds using the developed high-throughput assay.
- Validation of identified ATM kinase inhibitors through secondary assays.
Main Results:
- Successful development of a novel cell-based assay for ATM kinase.
- Screening identified additional small molecules that inhibit ATM kinase activity.
- The new assay provides a robust tool for discovering ATM inhibitors.
Conclusions:
- The developed cell-based assay is effective for high-throughput screening of ATM kinase inhibitors.
- New ATM inhibitors were discovered, offering potential for improved cancer radiotherapy.
- This assay addresses the need for a practical screening tool for ATM kinase inhibitors.
