Department of Breast Surgery, The First Affiliated Hospital of Nanjing Medical University, 300 Guangzhou Road, Nanjing, Jiangsu, 210029, People's Republic of China.
Mol Cancer. 2018 Jan 8;17(1):4. doi: 10.1186/s12943-017-0754-0.
Triple-negative breast cancer (TNBC) is highly invasive and aggressive and lacks specific molecular targets to improve the prognosis. MiR-25-3p promotes proliferation of many tumors and its role and underlying mechanisms in TNBC remain to be well elucidated.
Differential expression of miR-25-3p in TNBC was measured with quantitative real-time PCR (qRT-PCR) in both TNBC tissues and cell lines and was validated in the Cancer Genome Atlas (TCGA) database. The effects of miR-25-3p on proliferation, apoptosis capacity of TNBC were evaluated using Cell counting kit-8 (CCK-8), colony formation assay and Annexin V-FITC/PI analyses. The tumor growth in vivo was observed in xenograft model. Luciferase reporter assay, qPCR and western blot were performed to validate a potential target of miR-25-3p in TNBC. Involvement of the AKT and MAPK pathways was investigated by western blot.
MiR-25-3p was found to be upregulated in TNBC in tissues and cell lines. MiR-25-3p promoted TNBC cell proliferation in vitro and tumor growth in xenograft model, while suppression of miR-25-3p induced cell apoptosis. The luciferase reporter assay confirmed that B-cell translocation gene 2 (BTG2) might be a direct target of miR-25-3p, and its expression was negatively regulated by miR-25-3p. Moreover, inhibition of BTG2 expression accounted for the role of miR-25-3p in TNBC. Furthermore, BTG2 suppression might indirectly activate the AKT and ERK-MAPK signaling pathways to mediate the downstream effects of miR-25-3p.
This study demonstrates that miR-25-3p promotes proliferation by targeting tumor suppressor BTG2 and may identify new diagnostic and therapeutic targets in TNBC.
三阴性乳腺癌（TNBC）具有高度侵袭性和侵略性，缺乏改善预后的特定分子靶点。miR-25-3p 促进许多肿瘤的增殖，其在 TNBC 中的作用及其潜在机制仍有待充分阐明。
采用实时定量 PCR（qRT-PCR）测量 TNBC 组织和细胞系中 miR-25-3p 的差异表达，并在癌症基因组图谱（TCGA）数据库中进行验证。采用细胞计数试剂盒-8（CCK-8）、集落形成试验和 Annexin V-FITC/PI 分析评估 miR-25-3p 对 TNBC 增殖、凋亡能力的影响。在异种移植模型中观察体内肿瘤生长。通过荧光素酶报告基因检测、qPCR 和 Western blot 验证 TNBC 中 miR-25-3p 的潜在靶标。通过 Western blot 研究 AKT 和 MAPK 途径的参与情况。
发现 miR-25-3p 在 TNBC 组织和细胞系中上调。miR-25-3p 促进 TNBC 细胞体外增殖和异种移植模型中的肿瘤生长，而抑制 miR-25-3p 诱导细胞凋亡。荧光素酶报告基因检测证实 B 细胞易位基因 2（BTG2）可能是 miR-25-3p 的直接靶标，其表达受 miR-25-3p 的负调控。此外，BTG2 表达的抑制作用解释了 miR-25-3p 在 TNBC 中的作用。此外，BTG2 抑制可能间接激活 AKT 和 ERK-MAPK 信号通路，介导 miR-25-3p 的下游效应。
本研究表明，miR-25-3p 通过靶向肿瘤抑制因子 BTG2 促进增殖，可能为 TNBC 鉴定新的诊断和治疗靶点。
