Tang Shi, Wen Peiqi, Chen Yuanyuan, Li Kaiheng, Deng Jiehua, Chen Jinghui, Lai Lianghai
Department of Breast Surgery, Dongguan Maternal and Child Health Care Hospital, No. 99 Zhenxing Road, Dongcheng District, Dongguan, 523000, Guangdong, PR China.
J Mol Histol. 2025 Jul 9;56(4):222. doi: 10.1007/s10735-025-10506-3.
Triple-negative breast cancer (TNBC) is a subtype of breast cancer, and has a high recurrence rate. RING finger transmembrane-domain containing protein 2 (RNFT2) is a RING-finger E3 ubiquitin ligase that exerts oncogene functions in multiple malignant tumors such as bladder cancer and gastric cancer. However, RNFT2's role in TNBC is still unclear. Here, we investigated RNFT2's function and mechanism in TNBC. RNFT2 expressions in different stages of breast cancer were evaluated using the Gene Expression Profiling Interactive Analysis database. Overall survival (OS) in TNBC patients with high RNFT2 expressions was assessed with the Kaplan-Meier plotter database. Meanwhile, RNFT2 expressions in TNBC cells and tissues were determined using Western blot and quantitative real-time PCR. The relationship between RNFT2 and TNBC patients' OS rates was examined with Kaplan-Meier curve analysis. The correlation between RNFT2 expressions and TNBC clinicopathological data was estimated by the chi-square test. Moreover, RNFT2 functions in TNBC were determined using loss-of-function assay, Cell Counting Kit-8 analysis, Transwell, and tube formation assay. Furthermore, RNFT2's mechanism in TNBC was evaluated by prediction software, dual-luciferase reporter assay, and rescue experiments. Additionally, RNFT2's roles in TNBC in vivo were identified with cell-derived xenograft, hematoxylin-eosin staining, and immunohistochemical assays. RNFT2 was elevated in breast cancer, and owned different degrees of overexpression in breast cancer at different stages. Meanwhile, OS of TNBC patients with high RNFT2 expressions was poor. Also, RNFT2 expressions were positively correlated with size, TNM stage, and lymph node metastasis of TNBC. Functionally, silencing RNFT2 repressed TNBC cell proliferation, invasion, and angiogenesis. Mechanistically, miR-211-5p targeted RNFT2, and RNFT2 was negatively regulated by miR-211-5p in TNBC cells. Rescue assays further validated that miR-211-5p overexpression restrained TNBC cell proliferation, invasion, and angiogenesis, yet these impacts were abolished after RNFT2 overexpression. Meanwhile, animal experimental data further implied that RNFT2 knockdown reduced TNBC cell proliferation in vivo. RNFT2 facilitated TNBC development and predicted its adverse outcomes.
三阴性乳腺癌（TNBC）是乳腺癌的一种亚型，复发率较高。含RING指结构域跨膜蛋白2（RNFT2）是一种RING指E3泛素连接酶，在膀胱癌和胃癌等多种恶性肿瘤中发挥致癌基因功能。然而，RNFT2在TNBC中的作用仍不清楚。在此，我们研究了RNFT2在TNBC中的功能和机制。使用基因表达谱交互式分析数据库评估乳腺癌不同阶段的RNFT2表达。使用Kaplan-Meier绘图仪数据库评估RNFT2高表达的TNBC患者的总生存期（OS）。同时，使用蛋白质免疫印迹法和定量实时PCR测定TNBC细胞和组织中的RNFT2表达。通过Kaplan-Meier曲线分析检查RNFT2与TNBC患者OS率之间的关系。通过卡方检验估计RNFT2表达与TNBC临床病理数据之间的相关性。此外，使用功能丧失实验、细胞计数试剂盒-8分析、Transwell实验和管腔形成实验确定RNFT2在TNBC中的功能。此外，通过预测软件、双荧光素酶报告基因实验和拯救实验评估RNFT2在TNBC中的机制。此外，通过细胞来源的异种移植、苏木精-伊红染色和免疫组织化学实验确定RNFT2在TNBC体内的作用。RNFT2在乳腺癌中升高，并且在乳腺癌的不同阶段有不同程度的过表达。同时，RNFT2高表达的TNBC患者的OS较差。此外，RNFT2表达与TNBC的大小、TNM分期和淋巴结转移呈正相关。在功能上，沉默RNFT2可抑制TNBC细胞增殖、侵袭和血管生成。在机制上，miR-211-5p靶向RNFT2，并且在TNBC细胞中RNFT2受miR-211-5p负调控。拯救实验进一步证实，miR-211-5p过表达抑制TNBC细胞增殖、侵袭和血管生成，但在RNFT2过表达后这些影响被消除。同时，动物实验数据进一步表明，敲低RNFT2可降低TNBC细胞在体内的增殖。RNFT2促进TNBC的发展并预示其不良预后。
