Inhibition of both mutant and wild-type RAS-GTP in KRAS G12C colorectal cancer through cotreatment with G12C and EGFR inhibitors

Multiple KRAS G12C inhibitors are in development, and the identification of effective combination treatment regimens should maximize the benefit these agents have on cancer patients. Here, we find that KRAS G12C heterozygous mutated colorectal cancer cells are sensitive to targeting with EGFR therapeutic antibodies. We find that KRAS G12C is partially impaired in binding to tumor suppressor NF1 and also to RAF, and our computational simulations reveal how these deficiencies result in partial sensitivity to EGFR inhibition. For the combination of EGFR and G12C inhibitors we observe synergy and reductions in active forms of both wild-type and mutant RAS. Our simulations reveal the synergy involves both wild-type and mutant RAS. Overall, our work suggests that the addition of an EGFR inhibitor to a KRAS G12C inhibitor regimen should be further evaluated as a strategy for KRAS G12C colorectal cancer patients.