K-Ras is the most commonly mutated oncogene in human cancer. The recently approved non-small cell lung cancer drugs sotorasib and adagrasib covalently capture an acquired cysteine in K-Ras-G12C mutation and lock it in a signaling-incompetent state. However, covalent inhibition of G12D, the most frequent K-Ras mutation particularly prevalent in pancreatic ductal adenocarcinoma, has remained elusive due to the lack of aspartate-targeting chemistry. Here we present a set of malolactone-based electrophiles that exploit ring strain to crosslink K-Ras-G12D at the mutant aspartate to form stable covalent complexes. Structural insights from X-ray crystallography and exploitation of the stereoelectronic requirements for attack of the electrophile allowed development of a substituted malolactone that resisted attack by aqueous buffer but rapidly crosslinked with the aspartate-12 of K-Ras in both GDP and GTP state. The GTP-state targeting allowed effective suppression of downstream signaling, and selective inhibition of K-Ras-G12D-driven cancer cell proliferation in vitro and xenograft growth in mice.

K-Ras 是人类癌症中最常见的突变癌基因。最近批准的非小细胞肺癌药物 sotorasib 和 adagrasib 共价捕获 K-Ras-G12C 突变中的获得性半胱氨酸，并将其锁定在信号传导无能状态。然而，由于缺乏天冬氨酸靶向化学物质，G12D（最常见的 K-Ras 突变，在胰腺导管腺癌中尤其普遍）的共价抑制仍然难以捉摸。在这里，我们提出了一组基于丙二酸内酯的亲电子试剂，它们利用环应变在突变天冬氨酸处交联 K-Ras-G12D，形成稳定的共价复合物。来自 X 射线晶体学的结构见解和对亲电子试剂攻击的立体电子要求的开发，使得能够开发出一种取代的丙二酸内酯，它可以抵抗水性缓冲液的攻击，但在 GDP 和 GTP 状态下都能与 K-Ras 的天冬氨酸 12 快速交联。GTP 状态靶向可以有效抑制下游信号传导，并选择性抑制 K-Ras-G12D 驱动的体外癌细胞增殖和小鼠异种移植物生长。