Department of Oncology, Ningbo No.2 Hospital, Ningbo, Zhejiang, PR China.
Department of Breast Surgery, Ningbo No.2 Hospital, Ningbo, Zhejiang, PR China.
Cancer Gene Ther. 2024 Aug;31(8):1186-1200. doi: 10.1038/s41417-024-00780-w. Epub 2024 May 7.
TRIM58 is a member of the TRIM protein family, which possess with E3 ubiquitin ligase activities. Studies have revealed that low expression of TRIM58 plays key roles, has been implicated in the tumor progression of tumor formation due to its reduced expression. However, its role in regulating the stemness of breast cancer stem cells (CSCs) remains unexplored. Here, we found that TRIM58 was underexpressed in TNBC tissues and cells compared to adjacent mucosa tissue, and its downregulation was significantly associated with shorter survival. Overexpression of TRIM58 reduced the proportion of CD44 + /CD24- cells, upregulated differentiation genes, and inhibited stemness-related gene expression in TNBC CSCs. In vitro and in vivo experiments revealed that TRIM58 overexpression in CSCs suppressed tumor sphere formation and tumorigenic capacity. Co-IP results indicated direct interaction between TRIM58 and MYH9, with TRIM58 inducing MYH9 degradation via ubiquitination in differentiated cells. Label-free quantitative proteomics identified GRK3 and Hippo-YAP as downstream targets and signaling pathways of MYH9. TIMER database analysis, immunohistochemistry, western blotting, DNA-protein pulldown experiments, and dual luciferase reporter assays demonstrated that MYH9 regulated GRK3 transcriptional activation in CSCs. In conclusion, elevated TRIM58 expression in CSCs downregulates MYH9 protein levels by promoting ubiquitin-mediated degradation, thereby inhibiting downstream GRK3 transcription, inactivating the YAP stemness pathway, and ultimately promoting CSC differentiation.
TRIM58 是 TRIM 蛋白家族的成员，具有 E3 泛素连接酶活性。研究表明，TRIM58 表达水平降低在肿瘤形成中起着关键作用，由于其表达降低，与肿瘤的进展有关。然而，其在调节乳腺癌干细胞（CSC）的干性方面的作用仍未被探索。在这里，我们发现与相邻粘膜组织相比，TNBC 组织和细胞中 TRIM58 表达下调，其下调与生存时间缩短显著相关。TRIM58 的过表达降低了 CD44+/CD24-细胞的比例，上调了分化基因，并抑制了 TNBC CSCs 中的干性相关基因表达。体外和体内实验表明，CSC 中 TRIM58 的过表达抑制了肿瘤球形成和致瘤能力。Co-IP 结果表明 TRIM58 与 MYH9 之间存在直接相互作用，TRIM58 通过泛素化在分化细胞中诱导 MYH9 降解。无标记定量蛋白质组学鉴定出 GRK3 和 Hippo-YAP 是 MYH9 的下游靶标和信号通路。TIMER 数据库分析、免疫组织化学、western blot、DNA-蛋白质 pulldown 实验和双荧光素酶报告基因 assay 表明，MYH9 在 CSCs 中调节 GRK3 的转录激活。总之，CSC 中 TRIM58 表达的升高通过促进泛素介导的降解下调 MYH9 蛋白水平，从而抑制下游 GRK3 转录，使 YAP 干性通路失活，最终促进 CSC 分化。
