Wang Gang, Cai Chengzhong, Chen Lei
Cell Physiol Biochem. 2016;38(3):1030-9. doi: 10.1159/000443054. Epub 2016 Mar 4.
BACKGROUND/AIMS: Thyroid carcinoma (TC) is a highly lethal malignant cancer and its carcinogenesis remains undetermined. Dysregulation of microRNAs (miRNAs) is well known to be involved in the development of various cancers, including TC, whereas a role of miR-3666 in the pathogenesis of TC has not been appreciated.
We analyzed the levels of MET and miR-3666 in TC tissue and the relationship of miR-3666 levels with patients' prognosis. We then overexpressed miR-3666 by miRNA mimics transfection and inhibited miR-3666 by miRNA antisense transfection in TC cells. Cell survival and growth were analyzed by CCK-8 assay and MTT assay, respectively. Cell apoptosis and proliferation were analyzed by flow cytometry. Bioinformatics analyses were applied to predict miR-3666 targets, which was then confirmed using luciferase reporter assay.
We detected significantly higher levels of MET, and significantly lower levels of miR-3666 in TC tissue, compared to the adjacent non-tumor tissue. Moreover, the low miR-3666 levels were associated with poor survival of the patients. Overexpression of miR-3666 significantly inhibited cell growth, while depletion of miR-3666 increased cell growth in TC cells. Moreover, the effects of miR-3666 on cell growth appeared to result from alteration in cell proliferation, rather than changes in cell apoptosis. MiR-3666 was found to bind to the 3'-UTR of MET mRNA to inhibit its translation in TC cells.
Reduced miR-3666 levels in TC tissue may promotes TC growth, possibly through MET-mediated cell proliferation.
背景/目的：甲状腺癌（TC）是一种具有高度致死性的恶性肿瘤，其致癌机制尚不清楚。众所周知，微小RNA（miRNA）失调参与包括TC在内的各种癌症的发生发展，而miR-3666在TC发病机制中的作用尚未得到认识。
我们分析了TC组织中MET和miR-3666的水平以及miR-3666水平与患者预后的关系。然后，我们通过miRNA模拟物转染在TC细胞中过表达miR-3666，并通过miRNA反义转染抑制miR-3666。分别通过CCK-8法和MTT法分析细胞存活和生长情况。通过流式细胞术分析细胞凋亡和增殖情况。应用生物信息学分析预测miR-3666的靶标，然后使用荧光素酶报告基因检测进行验证。
与相邻的非肿瘤组织相比，我们在TC组织中检测到MET水平显著升高，而miR-3666水平显著降低。此外，低miR-3666水平与患者的不良生存相关。miR-3666的过表达显著抑制细胞生长，而miR-3666的缺失则增加了TC细胞的生长。此外，miR-3666对细胞生长的影响似乎是由细胞增殖的改变引起的，而不是细胞凋亡的变化。发现miR-3666与MET mRNA的3'-UTR结合以抑制其在TC细胞中的翻译。
TC组织中miR-3666水平降低可能通过MET介导的细胞增殖促进TC生长。
