Xing Shangping, Nong Feifei, Wang Yaqin, Huang Da, Qin Jialiang, Chen Yu-Fei, He Dan-Hua, Wu Pei-En, Huang Huicai, Zhan Ruoting, Xu Hui, Liu Yong-Qiang
Research Center of Chinese Herbal Resources Science and Engineering, School of Pharmaceutical Sciences, Guangzhou University of Chinese Medicine, Guangzhou 510006, China; Key Laboratory of Chinese Medicinal Resource from Lingnan, Ministry of Education, Guangzhou University of Chinese Medicine, Guangzhou 510006, China.
Science and Technology Innovation Center, Guangzhou University of Chinese Medicine, Guangzhou 510006, China.
Pharmacol Res. 2022 Feb;176:106059. doi: 10.1016/j.phrs.2022.106059. Epub 2022 Jan 5.
Skp1-Cul1-F-box protein (SCF) ubiquitin E3 ligases play important roles in cancer development and serve as a promising therapeutic target in cancer therapy. Brusatol (Bru), a known Nrf2 inhibitor, holds promise for treating a wide range of tumors; however, the direct targets of Bru and its anticancer mode of action remain unclear. In our study, 793 Bru-binding candidate proteins were identified by using a biotin-brusatol conjugate (Bio-Bru) followed by streptavidin-affinity pull down-based mass spectrometry. We found that Bru can directly bind to Skp1 and disrupt the interactions of Skp1 with the F-box protein Skp2, leading to the inhibition of the Skp2-SCF E3 ligase. Bru inhibited both proliferation and migration via promoting the accumulation of the substrates p27 and E-cadherin; Skp1 overexpression attenuated while Skp1 knockdown enhanced these effects of Bru in non-small cell lung cancer (NSCLC) cells. Moreover, Bru binding to Skp1 also inhibited the β-TRCP-SCF E3 ligase. In both subcutaneous and orthotopic NSCLC xenografts, Bru significantly inhibited the growth and metastasis of NSCLC through targeting SCF complex and upregulating p27 and E-cadherin protein levels. These data demonstrate that Bru is a Skp1-targeting agent that may have therapeutic potentials in lung cancer.
Skp1-Cul1-F盒蛋白（SCF）泛素E3连接酶在癌症发展中起重要作用，是癌症治疗中一个有前景的治疗靶点。已知的Nrf2抑制剂布鲁斯他汀（Bru）有望治疗多种肿瘤；然而，Bru的直接靶点及其抗癌作用模式仍不清楚。在我们的研究中，通过使用生物素-布鲁斯他汀偶联物（Bio-Bru），随后基于链霉亲和素亲和下拉的质谱法，鉴定出793种Bru结合候选蛋白。我们发现Bru可以直接与Skp1结合，并破坏Skp1与F盒蛋白Skp2的相互作用，从而导致Skp2-SCF E3连接酶的抑制。Bru通过促进底物p27和E-钙黏蛋白的积累来抑制增殖和迁移；Skp1过表达减弱而Skp1敲低增强了Bru在非小细胞肺癌（NSCLC）细胞中的这些作用。此外，Bru与Skp1的结合也抑制了β-TRCP-SCF E3连接酶。在皮下和原位NSCLC异种移植模型中，Bru通过靶向SCF复合物并上调p27和E-钙黏蛋白的蛋白水平，显著抑制了NSCLC的生长和转移。这些数据表明，Bru是一种靶向Skp1的药物，可能在肺癌治疗中具有治疗潜力。
