SCD1 inhibition causes cancer cell death by depleting mono-unsaturated fatty acids

Area of Science:

• Biochemistry
• Cancer Biology
• Metabolic Pathways

Background:

• Tumor cell proliferation necessitates increased metabolism.
• Fatty acid metabolism is crucial for cancer cell survival and growth.
• Understanding the dependence of tumor cells on fatty acid synthesis is vital for developing targeted therapies.

Purpose of the Study:

• To investigate the role of fatty acid synthesis pathway enzymes in colon cancer cell proliferation.
• To identify and characterize small-molecule inhibitors targeting fatty acid synthesis.
• To establish fatty acid synthesis as a viable therapeutic target in cancer.

Main Methods:

• RNA interference (RNAi) was used to deplete key fatty acid synthesis enzymes (SCD1, FASN, ACC1) in HCT116 colon cancer cells.
• A fatty acid rescue strategy was employed to assess the conditional cytotoxicity of enzyme depletion and drug treatment.
• Small-molecule inhibitors of fatty acid synthesis were characterized, including TOFA as an SCD1 inhibitor.

Main Results:

• Depletion of SCD1, FASN, or ACC1 resulted in reversible cytotoxicity in HCT116 cells, with SCD1 depletion showing the most pronounced effect.
• TOFA was identified as a potent SCD1 inhibitor.
• Reference FASN and ACC inhibitors exhibited less pronounced cytotoxicity compared to TOFA.
• Two SCD1 inhibitors demonstrated low-nanomolar cytotoxicity, significantly reduced by exogenous oleate, and one slowed tumor growth in xenografts.

Conclusions:

• Fatty acid synthesis is essential for colon cancer cell survival.
• SCD1 is a critical target in the fatty acid synthesis pathway for cancer therapy.
• The study provides a robust strategy for evaluating the specificity and potency of fatty acid synthesis inhibitors.