Strain-release alkylation of Asp12 enables mutant selective targeting of K-Ras-G12D
K-Ras is the most frequently mutated oncogene in human cancers. Recently approved drugs for non-small cell lung cancer, sotorasib and adagrasib, work by covalently binding to an acquired cysteine in the K-Ras-G12C mutation, locking the protein in an inactive state. However, covalently targeting the G12D mutation, the most common K-Ras mutation, especially in pancreatic ductal adenocarcinoma, has proven challenging due to the absence of chemistry capable of targeting K-Ras(G12C) inhibitor 12 aspartate. In this study, we introduce a class of malolactone-based electrophiles that leverage ring strain to crosslink K-Ras-G12D at the mutant aspartate, forming stable covalent complexes. X-ray crystallography provided structural insights, enabling the design of a substituted malolactone that avoids reaction with aqueous buffers but efficiently crosslinks with aspartate-12 in both the GDP- and GTP-bound states of K-Ras. Targeting the GTP-bound state led to effective inhibition of downstream signaling and selectively suppressed the proliferation of K-Ras-G12D-driven cancer cells in vitro, as well as tumor growth in mouse xenograft models.