Ma Zhenhai, Li Yang, Xu Jingchao, Ren Qiaozhen, Yao Jihong, Tian Xiaofeng
Breast Cancer Key Laboratory of Dalian, Department of Breast Disease and Reconstruction Center, The Second Affiliated Hospital of Dalian Medical University, Dalian, Liaoning, People's Republic of China.
Department of Pharmacology, Dalian Medical University, Dalian, Liaoning, People's Republic of China.
IUBMB Life. 2016 May;68(5):394-402. doi: 10.1002/iub.1494. Epub 2016 Apr 15.
MicroRNA-409-3p (miR-409-3p) is an miRNA expressed by embryonic stem cells, and our previous study demonstrated depressed miR-409-3p expression in human breast cancer (BC) cell lines; however, its role and function in BC metastasis are still unknown. The purpose of this study was to examine the expression levels of miR-409-3p in human BC and its role in the metastasis of BC. We analyzed the status of miR-409-3p expression in BC tissues by quantitative real-time polymerase chain reaction (PCR) and its relationship to the clinicopathologic features of patients with BC. To study the role of miR-409-3p in BC metastasis, the invasion ability of BC cells was detected by transwell invasion assays and wound healing assays. WST-1 assays and colony formation assays were used to investigate cell proliferation. Luciferase reporter assays were used to verify that miR-409-3p targeted zinc-finger E-box-binding homeobox 1 (ZEB1). Western blot analyses and transwell assays were carried out to assess ZEB1 expression and its role in BC cell metastasis. The expression of miR-409-3p was lower in tumor tissues than in noncancerous breast tissues. We verified that miR-409-3p levels were downregulated and significantly correlated with poor outcomes in patients with BC. Overexpression of miR-409-3p inhibited cellular proliferation and suppressed cellular migration and invasion in vitro and in vivo. Dual-luciferase reporter assays showed that miR-409-3p binds the 3'-untranslated region (3'-UTR) of ZEB1, suggesting that ZEB1 is a direct target of miR-409-3p. Western blot analysis confirmed that overexpression of miR-409-3p reduced ZEB1 protein levels. These data demonstrate that miR-409-3p plays an important role in regulating the metastasis of BC, which is involved in the post-transcriptional repression of ZEB1. Our results indicate that miR-409-3p can regulate the invasion and metastasis process of BC by targeting ZEB1 and may serve as a new prognostic marker and therapeutic target for treating BC metastasis. © 2016 IUBMB Life, 68(5):394-402, 2016.
微小RNA-409-3p（miR-409-3p）是一种由胚胎干细胞表达的微小RNA，我们之前的研究表明，在人乳腺癌（BC）细胞系中miR-409-3p表达降低；然而，其在BC转移中的作用和功能仍不清楚。本研究的目的是检测miR-409-3p在人BC中的表达水平及其在BC转移中的作用。我们通过定量实时聚合酶链反应（PCR）分析了BC组织中miR-409-3p的表达状态及其与BC患者临床病理特征的关系。为了研究miR-409-3p在BC转移中的作用，通过Transwell侵袭试验和伤口愈合试验检测了BC细胞的侵袭能力。使用WST-1试验和集落形成试验来研究细胞增殖。荧光素酶报告试验用于验证miR-409-3p靶向锌指E盒结合同源框1（ZEB1）。进行蛋白质印迹分析和Transwell试验以评估ZEB1的表达及其在BC细胞转移中的作用。miR-409-3p在肿瘤组织中的表达低于非癌性乳腺组织。我们证实miR-409-3p水平下调，并且与BC患者的不良预后显著相关。miR-409-3p的过表达在体外和体内均抑制细胞增殖并抑制细胞迁移和侵袭。双荧光素酶报告试验表明miR-409-3p与ZEB1的3'-非翻译区（3'-UTR）结合，提示ZEB1是miR-409-3p的直接靶点。蛋白质印迹分析证实miR-409-3p的过表达降低了ZEB1蛋白水平。这些数据表明miR-409-3p在调节BC转移中起重要作用，其参与ZEB1的转录后抑制。我们的结果表明，miR-409-3p可通过靶向ZEB1调节BC的侵袭和转移过程，并可能作为治疗BC转移的新的预后标志物和治疗靶点。©2016国际生物化学与分子生物学联盟生命科学，68(5):394 - 402，2016。
