Hu Anqi, Zhang Lin, Cao Lei, Li Haifeng, Huang Riqing, Zhou Xiaohong, Shi Yanxia, Li Baojiang
State Key Laboratory of Oncology in South China, Sun Yat-Sen University Cancer Center, Guangzhou 510050, China; Department of Medical Oncology, Sun Yat-sen University Cancer Center, Guangzhou 510050, China.
Department of Breast Surgery, Tai'an City Central Hospital, 29 Longtan Road, Tai'an City, Shandong 271000, China.
Transl Oncol. 2025 Apr;54:102321. doi: 10.1016/j.tranon.2025.102321. Epub 2025 Feb 21.
RING finger protein 135 (RNF135) is identified as a regulator in certain cancer types. However, its role and molecular mechanisms in breast cancer are still unclear.
Herein, we investigated the level of RNF135 in tumor tissues of breast patients using the online database and confirmed the data by real-time PCR and western blot analysis. The effects of RNF135 on stemness maintenance and migration/invasion capability of breast cells were investigated by sphere formation, flow cytometry, and transwell assays. Limiting dilution xenograft assay and metastatic model were applied to assess the implications of RNF135 in tumorigenesis, chemoresistance, and metastasis.
Our results revealed that RNF135 was upregulated in tumor tissues of breast patients, especially in metastatic patients. Knockdown of RNF135 suppressed stemness, and migration/invasion capability of breast cancer cells. Conversely, RNF135 overexpression enhanced the stemness and migration/invasion ability of breast cancer cells. Limiting dilution xenograft and metastatic assays demonstrated that RNF135 was required for the self-renewal of CSCs to initiate breast cancer development and metastasis. Mechanistically, DDX58 was identified as the substrate of RNF135 and RNF135 could facilitated the ubiquitination and degradation of DDX58. Notably, overexpression of DDX58 rescued the promoting effects of RNF135 on the stemness and migration/invasion ability of breast cancer cells.
Overall, our results implied that RNF135 promotes the stemness of breast cancer cells by ubiquitinating and degrading DDX58 and targeting of RNF135/DDX58 axis might be a feasible method to suppress tumorigenesis and metastasis of breast cancer patients.
环指蛋白135（RNF135）被确定为某些癌症类型中的一种调节因子。然而，其在乳腺癌中的作用及分子机制仍不清楚。
在此，我们利用在线数据库研究了乳腺癌患者肿瘤组织中RNF135的水平，并通过实时PCR和蛋白质印迹分析对数据进行了确认。通过成球实验、流式细胞术和Transwell实验研究了RNF135对乳腺细胞干性维持及迁移/侵袭能力的影响。应用极限稀释异种移植实验和转移模型评估RNF135在肿瘤发生、化疗耐药和转移中的作用。
我们的结果显示，RNF135在乳腺癌患者的肿瘤组织中上调，尤其是在转移患者中。敲低RNF135可抑制乳腺癌细胞的干性及迁移/侵袭能力。相反，RNF135过表达增强了乳腺癌细胞的干性及迁移/侵袭能力。极限稀释异种移植和转移实验表明，RNF135是乳腺癌干细胞自我更新以启动乳腺癌发生和转移所必需的。机制上，DDX58被确定为RNF135的底物，RNF135可促进DDX58的泛素化和降解。值得注意的是，DDX58过表达挽救了RNF135对乳腺癌细胞干性及迁移/侵袭能力的促进作用。
总体而言，我们的结果表明，RNF135通过泛素化和降解DDX58促进乳腺癌细胞的干性，靶向RNF135/DDX58轴可能是抑制乳腺癌患者肿瘤发生和转移的一种可行方法。
