MicroRNA‑335 is downregulated in papillary thyroid cancer and suppresses cancer cell growth, migration and invasion by directly targeting ZEB2
- Quan'e Kan
- Yong Su
- Huihui Yang
Published online on: October 3, 2017
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.