College of Life Sciences, North China University of Science and Technology, Tangshan, Hebei 063210, P.R. China.
Department of Life Sciences, Tangshan Normal University, Tangshan, Hebei 063000, P.R. China.
Int J Mol Med. 2020 Oct;46(4):1562-1570. doi: 10.3892/ijmm.2020.4685. Epub 2020 Jul 27.
MicroRNAs (miRNAs or miRs) play an important role in the tumorigenesis and progression of breast cancer. However, the function of miR‑28‑5p in breast cancer migration has yet to be determined. In the present study, Human MicroRNA Expression Database (HMED) analysis revealed that the expression level of miR‑28‑5p was significantly lower in breast cancer tissue than in normal breast tissue. Kaplan-‑Meier plotter (KMPLOT) analysis revealed that the low expression level of miR‑28‑5p was associated with a poor survival in breast cancer. In addition, reverse transcription‑quantitative PCR (RT‑qPCR) revealed that the expression of miR‑28‑5p was significantly lower in breast cancer cell lines compared with that in human mammary epithelial cells (HMECs). Moreover, transfection with miR‑28‑5p mimics suppressed the migration of MCF‑7 cells, whereas an miR‑28‑5p inhibitor exerted the opposite effect. Gene chip assay identified 648 differentially expressed genes (DEGs) in cells overexpressing miR‑28‑5p. The DEGs are enriched in the 'focal adhesion' and 'pathway in cancer' pathways. The expression levels of Ras‑related protein Rap‑1b (RAP1B), WD repeat and SOCS box containing 2 (WSB2) and vascular endothelial growth factor A (VEGFA) were confirmed by RT‑qPCR. Furthermore, transfection with miR‑28‑5p mimics decreased WSB2 expression, whereas the miR‑28‑5p inhibitor increased the expression of WSB2, at both the transcriptional and translational levels. miR‑28‑5p targets the 3'UTR of WSB2, and the binding site is conserved in multiple species, with a consensus motif of 5'‑AGCUCCUU‑3'. Moreover, WSB2 overexpression promoted the migration of MCF‑7 cells which had been inhibited by miR‑28‑5p. UALCAN analysis revealed that WSB2 was significantly upregulated in primary breast tumor tissue, and a high expression level of WSB2 was associated with a poor survival in breast cancer. Furthermore, immunohistochemistry revealed that the expression of WSB2 was markedly higher in breast cancer tissue compared with that in adjacent normal breast tissue. Taken together, the findings of the present study demonstrate that miR‑28‑5p inhibits the migration of breast cancer cells by regulating WSB2 expression, and the miR‑28‑5p/WSB2 axis may be a novel therapeutic target in breast cancer.
微小 RNA（miRNAs 或 miRs）在乳腺癌的发生和发展中发挥着重要作用。然而，miR-28-5p 在乳腺癌迁移中的功能尚待确定。本研究通过人类微小 RNA 表达数据库（HMED）分析显示，miR-28-5p 在乳腺癌组织中的表达水平明显低于正常乳腺组织。Kaplan-Meier plotter（KMPLOT）分析显示，miR-28-5p 低表达与乳腺癌患者的不良预后相关。此外，逆转录定量 PCR（RT-qPCR）显示，miR-28-5p 在乳腺癌细胞系中的表达明显低于人乳腺上皮细胞（HMECs）。此外，转染 miR-28-5p 模拟物可抑制 MCF-7 细胞的迁移，而 miR-28-5p 抑制剂则产生相反的效果。基因芯片检测发现，过表达 miR-28-5p 的细胞中有 648 个差异表达基因（DEGs）。DEGs 富集在“粘着斑”和“癌症途径”途径中。Ras 相关蛋白 Rap-1b（RAP1B）、WD 重复和 SOCS 框包含 2（WSB2）和血管内皮生长因子 A（VEGFA）的表达水平通过 RT-qPCR 得到证实。此外，转染 miR-28-5p 模拟物可降低 WSB2 的表达，而 miR-28-5p 抑制剂可增加 WSB2 的表达，在转录和翻译水平均如此。miR-28-5p 靶向 WSB2 的 3'UTR，该结合位点在多个物种中保守，具有 5'-AGCUCCUU-3'的保守基序。此外，WSB2 的过表达促进了被 miR-28-5p 抑制的 MCF-7 细胞的迁移。UALCAN 分析显示，WSB2 在原发性乳腺癌组织中显著上调，并且 WSB2 的高表达与乳腺癌患者的不良预后相关。此外，免疫组织化学显示，WSB2 在乳腺癌组织中的表达明显高于相邻的正常乳腺组织。综上所述，本研究结果表明，miR-28-5p 通过调节 WSB2 的表达抑制乳腺癌细胞的迁移，miR-28-5p/WSB2 轴可能成为乳腺癌的一种新的治疗靶点。
