The hedgehog (Hh) signaling pathway has long been a hotspot for anti-cancer drug development due to its important role in cell proliferation and tumorigenesis. However, most clinically available Hh pathway inhibitors target the seven-transmembrane region (7TM) of smoothened (SMO), and the acquired drug resistance is an urgent problem in SMO inhibitory therapy. Here, we identify a sterol analog Q29 and show that it can inhibit the Hh pathway through binding to the cysteine-rich domain (CRD) of SMO and blocking its cholesterylation. Q29 suppresses Hh signaling-dependent cell proliferation and arrests Hh-dependent medulloblastoma growth. Q29 exhibits an additive inhibitory effect on medulloblastoma with vismodegib, a clinically used SMO-7TM inhibitor for treating basal cell carcinoma (BCC). Importantly, Q29 overcomes resistance caused by SMO mutants against SMO-7TM inhibitors and inhibits the activity of SMO oncogenic variants. Our work demonstrates that the SMO-CRD inhibitor can be a new way to treat Hh pathway-driven cancers.

由于其在细胞增殖和肿瘤发生中的重要作用，hedgehog（Hh）信号通路长期以来一直是抗癌药物开发的热点。然而，临床上可用的Hh通路抑制剂大多针对平滑化（SMO）的七跨膜区（7TM），而获得性耐药是SMO抑制治疗中亟待解决的问题。在这里，我们鉴定了一种甾醇类似物 Q29，并表明它可以通过与 SMO 的富含半胱氨酸结构域 (CRD) 结合并阻断其胆固醇化来抑制 Hh 通路。 Q29 抑制 Hh 信号依赖性细胞增殖并阻止 Hh 依赖性髓母细胞瘤生长。 Q29 与 vismodegib（一种临床用于治疗基底细胞癌 (BCC) 的 SMO-7TM 抑制剂）一起对髓母细胞瘤表现出附加抑制作用。重要的是，Q29克服了SMO突变体对SMO-7TM抑制剂引起的耐药性，并抑制SMO致癌变异体的活性。我们的工作表明，SMO-CRD 抑制剂可以成为治疗 Hh 通路驱动的癌症的新方法。