Dependence on the Pyrimidine Biosynthetic Enzyme DHODH Is a Synthetic Lethal Vulnerability in Mutant KRAS-Driven...

Area of Science:

• Oncology
• Molecular Biology
• Drug Discovery

Background:

• Activating KRAS mutations are critical drivers in various cancers.
• Traditional synthetic lethal screens in monolayer cultures may not fully represent tumor biology, limiting drug discovery.
• Developing effective KRAS-targeted therapies remains a significant challenge.

Purpose of the Study:

• To identify novel small molecules selectively inhibiting KRAS-mutant cancer cell growth using a high-throughput screen.
• To uncover the molecular targets of these identified inhibitors.
• To evaluate the therapeutic potential of targeting identified pathways in preclinical cancer models.

Main Methods:

• High-throughput synthetic lethal screening of small molecules in soft agar to model tumor microenvironment.
• Chemoproteomic profiling to identify the molecular targets of active compounds.
• Metabolic pathway analysis to understand the effects of target inhibition.
• In vivo studies using pancreatic tumor xenograft models to assess antitumor efficacy.

Main Results:

• A screen identified selective inhibitors of KRAS-mutant cell growth in soft agar.
• Chemoproteomic profiling pinpointed dihydroorotate dehydrogenase (DHODH) as the target for the most potent KRAS-selective compounds.
• DHODH inhibition was found to disrupt multiple cellular metabolic pathways.
• Significant antitumor activity was observed in vivo in a pancreatic cancer xenograft model upon DHODH inhibition.

Conclusions:

• Dihydroorotate dehydrogenase (DHODH) is a validated synthetic lethal target in KRAS-mutant cancers.
• Targeting DHODH with small molecule inhibitors demonstrates promising preclinical efficacy.
• DHODH inhibition represents a potential therapeutic strategy for KRAS-driven tumors.