Engineering Forward Genetics into Cultured Cancer Cells for Chemical Target Identification

Area of Science:

• Genetics
• Molecular Biology
• Drug Discovery

Background:

• Identifying targets for small molecule drugs is a key challenge in drug discovery.
• Defective DNA mismatch repair (dMMR) cancer cells are useful for target identification, but naturally occurring dMMR cell lines are scarce.
• Existing methods for forward genetic screening in mammalian cells are limited.

Purpose of the Study:

• To establish a novel platform for forward genetic screening using engineered DNA mismatch repair (dMMR) in mammalian cells.
• To overcome the limitation of scarce naturally occurring dMMR cancer cell lines for target identification.
• To demonstrate the utility of this platform for identifying drug mechanisms of action.

Main Methods:

• Utilized CRISPR/Cas9 gene editing technology to engineer dMMR into mammalian cells.
• Performed in vitro selections against three cellular toxins using engineered dMMR mouse and human cancer cell lines.
• Analyzed drug-resistant clones to identify compound-resistant alleles.

Main Results:

• Successfully engineered dMMR into mammalian cancer cell lines.
• Demonstrated the platform's ability to identify mechanisms of drug action.
• Observed the emergence of compound-resistant alleles in drug-resistant clones, validating the screening approach.

Conclusions:

• Engineered dMMR provides a powerful tool for forward genetic screening in mammalian cells.
• This platform expands the utility of dMMR cells for target identification in drug discovery.
• The approach facilitates the discovery of drug mechanisms and potential therapeutic targets.