Selective and noncovalent targeting of RAS mutants for inhibition and degradation

Area of Science:

• Oncology
• Molecular Biology
• Drug Discovery

Background:

• Activating RAS mutations are prevalent in human cancers.
• Current clinical targeting of RAS is limited, primarily to KRAS G12C via covalent inhibitors.

Purpose of the Study:

• To develop novel noncovalent reagents targeting oncogenic RAS mutants.
• To investigate the therapeutic potential of a monobody targeting active KRAS G12V and G12C.

Main Methods:

• Development and characterization of a monobody (12VC1) targeting active KRAS mutants.
• Crystal structure analysis to elucidate binding interactions.
• In vitro and in vivo studies assessing inhibition of ERK activation, cancer cell proliferation, and tumor growth in mouse xenograft models.
• Fusion of 12VC1 to VHL for targeted protein degradation.

Main Results:

• The monobody 12VC1 binds KRAS G12V and G12C with high affinity, outcompeting RAS-effector interactions.
• Intracellular expression of 12VC1 potently inhibits ERK signaling and proliferation in RAS-driven cancer cells.
• 12VC1-VHL fusion enhances mutant KRAS suppression through targeted degradation.

Conclusions:

• Noncovalent targeting and degradation of active KRAS mutants is feasible.
• 12VC1 represents a promising starting point for developing new noncovalent therapeutics against oncogenic RAS.
• This strategy opens avenues for targeting previously undruggable RAS mutations.