State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China; University of Chinese Academy of Sciences, Beijing 100049, China.
State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China; Yunnan Key Laboratory of Natural Medicinal Chemistry, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China.
J Biol Chem. 2020 Mar 13;295(11):3576-3589. doi: 10.1074/jbc.RA119.011396. Epub 2020 Feb 6.
It has been well-established that the deubiquitinating enzyme ubiquitin-specific peptidase 7 (USP7) supports cancer growth by up-regulating multiple cellular pathways, including Wnt/β-catenin signaling. Therefore, considerable efforts are directed at identifying and developing USP7 inhibitors. Here, we report that sesquiterpene lactone parthenolide (PTL) inhibits USP7 activity, assessed with deubiquitinating enzyme activity assays, including fluorogenic Ub-AMC/Ub-Rho110, Ub-VME/PA labeling, and Di-Ub hydrolysis assays. Further investigations using cellular thermal shift (CETSA), surface plasmon resonance (SPR), and mass spectrum (MS) assays revealed that PTL directly interacts with USP7. Consistent with the role of USP7 in stimulating Wnt signaling and carcinogenesis, PTL treatment inhibited the activity of Wnt signaling partly by destabilizing β-catenin. Moreover, using cell viability assays, we found that PTL suppresses the proliferation of colorectal cancer cells and induces apoptosis in these cells. Additionally, we examined the effects of two other sesquiterpene lactones (costunolide and α-santonin) on USP7 and Wnt signaling and found that α-methylene-γ-butyrolactone may provide a scaffold for future USP7 inhibitors. In summary, our findings reveal that PTL inhibits USP7 activity, identifying a potential mechanism by which PTL suppresses Wnt/β-catenin signaling. We further suggest that sesquiterpene lactones might represent a suitable scaffold for developing USP7 inhibitors and indicate that PTL holds promise as an anticancer agent targeting aberrant USP7/Wnt signaling.
已经证实，去泛素化酶泛素特异性肽酶 7（USP7）通过上调多种细胞途径，包括 Wnt/β-catenin 信号通路，来支持癌症生长。因此，人们正在努力识别和开发 USP7 抑制剂。在这里，我们报告倍半萜内酯角鲨烯（PTL）通过去泛素化酶活性测定，包括荧光 Ub-AMC/Ub-Rho110、Ub-VME/PA 标记和 Di-Ub 水解测定，抑制 USP7 活性。使用细胞热转移（CETSA）、表面等离子体共振（SPR）和质谱（MS）测定的进一步研究表明，PTL 直接与 USP7 相互作用。与 USP7 刺激 Wnt 信号和致癌作用一致，PTL 处理通过使 β-catenin 不稳定来部分抑制 Wnt 信号的活性。此外，使用细胞活力测定，我们发现 PTL 抑制结直肠癌细胞的增殖并诱导这些细胞凋亡。此外，我们检查了另外两种倍半萜内酯（木香烯内酯和α-当归内酯）对 USP7 和 Wnt 信号的影响，发现α-亚甲基-γ-丁内酯可能为未来的 USP7 抑制剂提供支架。总之，我们的研究结果表明 PTL 抑制 USP7 活性，确定了 PTL 抑制 Wnt/β-catenin 信号的潜在机制。我们进一步提出，倍半萜内酯可能代表开发 USP7 抑制剂的合适支架，并表明 PTL 有希望成为针对异常 USP7/Wnt 信号的抗癌剂。
