Kan Quan'e, Su Yong, Yang Huihui
Department of Endocrinology, Henan Provincial People's Hospital, Zhengzhou, Henan 450003, P.R. China.
Oncol Lett. 2017 Dec;14(6):7622-7628. doi: 10.3892/ol.2017.7126. Epub 2017 Oct 3.
MicroRNAs (miRs) are a group of short, endogenous, non-protein-coding and single-stranded RNAs that regulate gene expression by binding to the 3'-untranslated region (3'UTR) of mRNAs, which results in their degradation or translational repression. The aim of the present study was to investigate the expression and function of miR-335 in human papillary thyroid cancer (PTC). Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) was performed to quantify the relative miR-335 expression levels in PTC tissues and cell lines. The effect of miR-335 on the proliferation, migration and invasion of PTC cells was assessed by an MTT assay, and transwell migration and invasion assays, respectively. Dual-luciferase reporter assays were employed to explore whether miR-335 directly targeted the 3'UTR of the potential target gene zinc finger E-box binding homeobox 2 (ZEB2). RT-qPCR and western blotting were adopted to assess the effect of miR-335 on the mRNA and protein expression of ZEB2. RT-qPCR revealed that miR-335 was downregulated in PTC tissues and cell lines. The MTT assay and transwell migration and invasion assays demonstrated that the overexpression of miR-335 significantly inhibited the proliferation, migration and invasion of PTC cells. ZEB2 was identified as a direct target of miR-335 with computational analysis, which was confirmed with a dual-luciferase reporter assay, RT-qPCR and western blotting. The knockdown of ZEB2 significantly inhibited the proliferation, migration and invasion of PTC cells, indicating that ZEB2 may be a functional target of miR-335. Taken together, these findings suggested that miR-335 functioned as a tumor suppressor and suppressed the growth and metastatic behavior of PTC cells by targeting ZEB2.
微小RNA（miR）是一组短的、内源性的、非蛋白质编码的单链RNA，它们通过与mRNA的3'-非翻译区（3'UTR）结合来调节基因表达，从而导致mRNA降解或翻译抑制。本研究的目的是探讨miR-335在人甲状腺乳头状癌（PTC）中的表达及功能。采用逆转录-定量聚合酶链反应（RT-qPCR）来定量PTC组织和细胞系中miR-335的相对表达水平。分别通过MTT法、Transwell迁移和侵袭实验评估miR-335对PTC细胞增殖、迁移和侵袭的影响。采用双荧光素酶报告基因实验来探究miR-335是否直接靶向潜在靶基因锌指E盒结合同源框2（ZEB2）的3'UTR。采用RT-qPCR和蛋白质印迹法评估miR-335对ZEB2 mRNA和蛋白质表达的影响。RT-qPCR结果显示，miR-335在PTC组织和细胞系中表达下调。MTT法、Transwell迁移和侵袭实验表明，miR-335过表达显著抑制PTC细胞的增殖、迁移和侵袭。通过计算分析确定ZEB2是miR-335的直接靶标，双荧光素酶报告基因实验、RT-qPCR和蛋白质印迹法证实了这一点。敲低ZEB2显著抑制PTC细胞的增殖、迁移和侵袭，表明ZEB2可能是miR-335的功能靶标。综上所述，这些发现提示miR-335作为一种肿瘤抑制因子，通过靶向ZEB2抑制PTC细胞的生长和转移行为。
