Chen Lei, Xu Lei, Wang Gang
Department of General Surgery, The Tenth People's Hospital, Tongji University, 301 Middle Yanchang Road, Shanghai, 200072, China.
Tumour Biol. 2015 Nov;36(11):8653-60. doi: 10.1007/s13277-015-3619-4. Epub 2015 Jun 6.
Thyroid carcinoma (TC) is a lethal cancer worldwide, whereas its carcinogenesis is not fully understood. Although growing evidence has demonstrated that dysregulation of microRNAs (miRNAs) contributes to the development of various cancers, the role of miRNAs in the pathogenesis of TC is poorly characterized. Here, we analyzed the levels of miR-449b in TC tissues and detected significantly lower miR-449b levels in TC tissues. Moreover, the low miR-449b levels were associated with poor survival. We then overexpressed miR-449b by miRNA mimic transfection and inhibited miR-449b by miRNA antisense transfection. Cell growth was analyzed by CCK-8 assay and MTT assay, and apoptosis and cell proliferation were analyzed by flow cytometry. Overexpression of miR-449b significantly inhibited cell growth, while depletion of miR-449b increased cell growth. Moreover, the effects of miR-449b on cell growth were through modulation of cell proliferation rather than through modulation of cell apoptosis. Targeted genes were predicted by a bioinformatics algorithm and confirmed by a dual luciferase reporter assay, showing that miR-449b binds to the 3'-UTR of MET (hepatocyte growth factor receptor) mRNA, to inhibit its expression in TC cells. MET levels were regulated by miR-449b in TT cells. Together, we show that reduced miR-449b levels in TT tissues may promote TC growth, through MET-mediated cell proliferation.
甲状腺癌（TC）是一种在全球范围内具有致死性的癌症，但其致癌机制尚未完全明确。尽管越来越多的证据表明，微小RNA（miRNA）失调与多种癌症的发生发展有关，但miRNA在TC发病机制中的作用仍不清楚。在此，我们分析了TC组织中miR-449b的水平，发现TC组织中miR-449b水平显著降低。此外，低水平的miR-449b与较差的生存率相关。然后，我们通过转染miRNA模拟物使miR-449b过表达，并通过转染miRNA反义物抑制miR-449b。通过CCK-8法和MTT法分析细胞生长情况，并通过流式细胞术分析细胞凋亡和细胞增殖情况。miR-449b过表达显著抑制细胞生长，而miR-449b缺失则促进细胞生长。此外，miR-449b对细胞生长的影响是通过调节细胞增殖而非调节细胞凋亡实现的。通过生物信息学算法预测靶基因，并通过双荧光素酶报告基因检测进行验证，结果表明miR-449b与MET（肝细胞生长因子受体）mRNA的3'-UTR结合，从而抑制其在TC细胞中的表达。在TT细胞中，MET水平受miR-449b调控。我们的研究表明，TT组织中miR-449b水平降低可能通过MET介导的细胞增殖促进TC生长。
