WRN helicase is a promising target for treatment of cancers with microsatellite instability (MSI) due to its essential role in resolving deleterious non-canonical DNA structures that accumulate in cells with faulty mismatch repair mechanisms^1,2,3,4,5. Currently there are no approved drugs directly targeting human DNA or RNA helicases, in part owing to the challenging nature of developing potent and selective compounds to this class of proteins. Here we describe the chemoproteomics-enabled discovery of a clinical-stage, covalent allosteric inhibitor of WRN, VVD-133214. This compound selectively engages a cysteine (C727) located in a region of the helicase domain subject to interdomain movement during DNA unwinding. VVD-133214 binds WRN protein cooperatively with nucleotide and stabilizes compact conformations lacking the dynamic flexibility necessary for proper helicase function, resulting in widespread double-stranded DNA breaks, nuclear swelling and cell death in MSI-high (MSI-H), but not in microsatellite-stable, cells. The compound was well tolerated in mice and led to robust tumour regression in multiple MSI-H colorectal cancer cell lines and patient-derived xenograft models. Our work shows an allosteric approach for inhibition of WRN function that circumvents competition from an endogenous ATP cofactor in cancer cells, and designates VVD-133214 as a promising drug candidate for patients with MSI-H cancers.

WRN 解旋酶是治疗具有微卫星不稳定性 (MSI) 的癌症的一个有前景的靶标，因为它在解决具有错误错配修复机制的细胞中积累的有害非规范 DNA 结构方面发挥着重要作用^1,2,3,4,5。目前还没有批准的药物直接针对人类 DNA 或 RNA 解旋酶，部分原因是开发针对此类蛋白质的有效和选择性化合物具有挑战性。在此，我们描述了基于化学蛋白质组学的 WRN 共价变构抑制剂 VVD-133214 的发现。该化合物选择性地接合位于解旋酶结构域区域的半胱氨酸 (C727)，在 DNA 解旋过程中会发生结构域间移动。 VVD-133214 与核苷酸协同结合 WRN 蛋白，并稳定缺乏适当解旋酶功能所需的动态灵活性的紧凑构象，导致 MSI 高 (MSI-H) 中广泛的双链 DNA 断裂、核肿胀和细胞死亡，但在 MSI-H 中则不然。微卫星稳定的细胞。该化合物在小鼠体内具有良好的耐受性，并在多种 MSI-H 结直肠癌细胞系和患者来源的异种移植模型中导致肿瘤强劲消退。我们的工作展示了一种抑制 WRN 功能的变构方法，可规避癌细胞中内源 ATP 辅因子的竞争，并将 VVD-133214 指定为 MSI-H 癌症患者的有前途的候选药物。