Targeting Trop2 by Bruceine D suppresses breast cancer metastasis by blocking Trop2/β-catenin positive feedback loop

作者：Wenjuan Tang, Yu Hu, Kai-hui Tu, Zhengyan Gong, Man Zhu, Tianfeng Yang, Ammar Sarwar, Bingling Dai, Dongdong Zhang, Yingzhuan Zhan, Yanmin Zhang · 发表于：Journal of Advanced Research · 年份：2023 · DOI：10.1016/j.jare.2023.05.012 · 被引用次数：36 · 研究领域：HER2/EGFR in Cancer Research、Breast Cancer Treatment Studies、Protein Kinase Regulation and GTPase Signaling

INTRODUCTION: Tumor-associated calcium signal transducer 2 (Trop2) has been used as a transport gate for cytotoxic agents into cells in antibody-drug conjugate designs because of its expression in a wide range of solid tumors. However, the specific role of Trop2 itself in breast cancer progression remains unclear and small molecules targeting Trop2 have not yet been reported. OBJECTIVES: To screen small molecules targeting Trop2, and to reveal its pharmacological effects and the molecular mechanisms of action. METHODS: Small molecule targeting Trop2 was identified by cell membrane chromatography, and validated by cellular thermal shift assay and point mutation analyses. We investigated the pharmacological effects of Trop2 inhibitor using RNA-seq, human foreskin fibroblast (HFF)-derived extracellular matrix (ECM), Matrigel drop invasion assays, colony-forming assay, xenograft tumor model, 4T1 orthotopic metastasis model and 4T1 experimental metastasis model. The molecular mechanism was determined using immunoprecipitation, mass spectrometry, immunofluorescence, immunohistochemistry and Western blotting. RESULTS: Here we identified Bruceine D (BD) as the inhibitor of Trop2, and demonstrated anti-metastasis effects of BD in breast cancer. Notably, Lys307 and Glu310 residues of Trop2 acted as critical sites for BD binding. Mechanistically, BD suppressed Trop2-induced cancer metastasis by blocking the formation of Trop2/β-catenin positive loop, in which the Trop2/β-catenin complex...