Department of Breast Surgery, Shanxi Bethune Hospital, Shanxi Academy of Medical Sciences, Tongji Shanxi Hospital, Third Hospital of Shanxi Medical University, 99 Longcheng Street, Taiyuan, 030032, Shanxi Province, China.
Mol Biotechnol. 2023 Sep;65(9):1465-1475. doi: 10.1007/s12033-022-00649-z. Epub 2023 Jan 18.
Aberrant scaffold attachment factor-B2 (SAFB2) expression is associated with several malignant tumors. In this study, we investigated how SAFB2 worked in the process of breast cancer as well as the underlying mechanism. Quantitative real-time polymerase chain reaction (qRT-PCR) and western blotting analysis were used to investigate the expression of SAFB2 and nuclear factor of activated T cells 5 (NFAT5). Cellular proliferative ability was detected with cell counting kit 8 (CCK8), colony formation and 5-Ethynyl-2'-deoxyuridine (EdU) staining assays. Cell apoptosis was measured via flow cytometry and western blotting analysis. Wound healing, transwell assays, and western blotting analysis were executed to estimate cell migration and invasion. The relationship between SAFB2 and NFAT5 was verified by RNA immunoprecipitation (RIP) assay and NFAT5 mRNA stability was examined with actinomycin (Act) D assay. Western blotting analysis also tested the expression of Wnt/β-catenin signaling-associated proteins. As a result, SAFB2 was downregulated in breast cancer cell lines, while NFAT5 was highly expressed in most breast cancer cell lines. Overexpression of SAFB2 suppressed the proliferation, migration, and invasion while exacerbated the apoptosis of breast cancer cells. SAFB2 interacted with NFAT5 mRNA and declined the stability of NFAT5 mRNA. Overexpression of NFAT5 counteracted anti-proliferative, anti-metastatic and pro-apoptotic effects of SAFB2 in breast cancer cells. Mechanistically, SAFB2 overexpression inhibited the Wnt/β-catenin signaling pathway, while this effect was partially eliminated by NFAT5. Collectively, SAFB2 hindered breast cancer development and inactivated Wnt/β-catenin signaling via regulation of NFAT5, suggesting that SAFB2 might be a promising therapeutic target for breast cancer.
异常支架附着因子-B2 (SAFB2) 的表达与几种恶性肿瘤有关。在这项研究中，我们研究了 SAFB2 在乳腺癌发生过程中的作用及其潜在机制。定量实时聚合酶链反应 (qRT-PCR) 和 Western blot 分析用于研究 SAFB2 和激活 T 细胞核因子 5 (NFAT5) 的表达。细胞计数试剂盒 8 (CCK8)、集落形成和 5-乙炔基-2'-脱氧尿苷 (EdU) 染色实验用于检测细胞增殖能力。通过流式细胞术和 Western blot 分析检测细胞凋亡。通过划痕愈合、Transwell 测定和 Western blot 分析评估细胞迁移和侵袭。通过 RNA 免疫沉淀 (RIP) 测定验证 SAFB2 和 NFAT5 之间的关系，并通过放线菌素 (Act) D 测定检测 NFAT5 mRNA 的稳定性。Western blot 分析还测试了 Wnt/β-连环蛋白信号相关蛋白的表达。结果显示，SAFB2 在乳腺癌细胞系中下调，而 NFAT5 在大多数乳腺癌细胞系中高表达。SAFB2 的过表达抑制了乳腺癌细胞的增殖、迁移和侵袭，同时加剧了细胞凋亡。SAFB2 与 NFAT5 mRNA 相互作用并降低 NFAT5 mRNA 的稳定性。NFAT5 的过表达逆转了 SAFB2 在乳腺癌细胞中的抗增殖、抗转移和促凋亡作用。从机制上讲，SAFB2 过表达抑制了 Wnt/β-连环蛋白信号通路，而 NFAT5 的过表达部分消除了这一作用。综上所述，SAFB2 通过调节 NFAT5 抑制乳腺癌的发展和激活 Wnt/β-连环蛋白信号，表明 SAFB2 可能是乳腺癌有前途的治疗靶点。
