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Updated: Apr 26, 2026
A Multiplexed Luciferase-based Screening Platform for Interrogating Cancer-associated Signal Transduction in Cultured Cells
Published on: July 3, 2013
A high-throughput assay for small molecule destabilizers of the KRAS oncoprotein
Joseph Carver1, Thomas S Dexheimer2, Dennis Hsu1
1Laboratory of Cancer Biology and Genetics, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland, United States of America.
Abstract:
Mutations in the Ras family of small GTPases, particularly KRAS, occur at high frequencies in cancer and represent a major unmet therapeutic need due to the lack of effective targeted therapies. Past efforts directed at inhibiting the activity of the Ras oncoprotein have proved difficult. We propose an alternative approach to target Ras by eliminating Ras protein from cells with pharmacological means. In this study, we developed a cell-based, high-content screening platform to identify small molecules that could promote the degradation of the KRAS oncoprotein. We generated an EGFP-KRASG12V fluorescence reporter system and implemented it for automated screening in 1536-well plates using high-throughput cellular imaging. We screened a library of clinically relevant compounds at wide dose range and identified Ponatinib and AMG-47a as two candidate compounds that selectively reduced the levels of EGFP-KRASG12V protein but did not affect EGFP protein in cells. This proof-of-principle study demonstrates that it is feasible to use a high-throughput screen to identify compounds that promote the degradation of the Ras oncoprotein as a new approach to target Ras.
Insights
Researchers developed a new screening method to find drugs that degrade the KRAS oncoprotein. This approach successfully identified compounds like Ponatinib, offering a novel strategy for targeting KRAS in cancer therapy.
Area of Science:
- Oncology
- Molecular Biology
- Drug Discovery
Background:
- Mutations in the Ras family, especially KRAS, are frequent in cancers, posing a significant therapeutic challenge.
- Targeting Ras oncoprotein activity directly has historically been difficult, necessitating alternative strategies.
Purpose of the Study:
- To develop a high-throughput screening platform for identifying small molecules that promote the degradation of the KRAS oncoprotein.
- To establish a novel pharmacological approach for targeting Ras-driven cancers.
Main Methods:
- Development of a cell-based, high-content screening platform utilizing an EGFP-KRASG12V fluorescence reporter system.
- Automated screening of a library of clinically relevant compounds using high-throughput cellular imaging in 1536-well plates.
Main Results:
- Identification of Ponatinib and AMG-47a as compounds that selectively reduce EGFP-KRASG12V protein levels.
- Demonstrated that these compounds do not affect EGFP protein levels, indicating specificity for KRAS.
Conclusions:
- Proof-of-principle that high-throughput screening can identify compounds promoting Ras oncoprotein degradation.
- This approach offers a feasible new strategy for targeting Ras in cancer treatment.
