Downregulation of miR-221 Inhibits Cell Migration and Invasion through Targeting Methyl-CpG Binding Domain Protein 2 in Human Oral Squamous Cell Carcinoma Cells.

Shuqi He,Zhiguo Liu,Wangxiang Yan,Renfa Lai,Yu Chen,Xueqiang Ding,Zhaoqiang Zhang,Dan Chen

doi:10.1155/2015/751672

Abstract

Oral squamous cell carcinoma (OSCC), the most frequent of all oral cancers, is a type of highly malignant tumors with a high capacity to invade locally and form distant metastases. An increasing number of studies have shown that microRNAs (miRNAs) play an important role in regulating cancer metastasis and invasion. In the present study, we detected the expression of miR-221 in two highly metastatic OSCC cell lines and two OSCC cell lines that are less metastatic using quantitative real-time PCR analysis (qRT-PCR). The qRT-PCR results indicate that miR-221 is upregulated in highly metastatic OSCC cell lines. Then, miR-221 expression was knocked down by transfection with miR-221 inhibitor, and UM1 cell migration and invasion were assessed using transwell migration and invasion assays. The results indicate that inhibition of miR-221 suppressed migration and invasion of UM1 cells. Furthermore, methyl-CpG binding domain protein 2 (MBD2) was identified as a direct target gene of miR-221. Additionally, MBD2 silencing could partly reverse the effect of miR-221 on cell migration and invasion. In conclusion, downregulation of miR-221 inhibits cell migration and invasion at least partially through targeting MBD2 in the human OSCC cell line UM1.

Highlights

Oral cancer, a type of head and neck cancer, is any cancerous tissue growth located in the oral cavity
We focused on demonstrating the function of miR-221 in Oral squamous cell carcinoma (OSCC) metastasis and invasion, and we identified the target of miR221 related to metastasis and invasion
The present study revealed that miR-221 is upregulated in highly metastatic OSCC cell lines and that downregulation of miR-221 inhibits cell migration and invasion partly through targeting methylCpG binding domain protein 2 (MBD2)

Summary

Introduction

A type of head and neck cancer, is any cancerous tissue growth located in the oral cavity. Oral cancer has been identified as a significant worldwide public health threat because its treatment often produces dysfunction and distortions in speech, mastication and swallowing, dental health, and even the ability to interact socially [1]. Local OSCC can be effectively controlled by surgical excision and radiotherapy, metastasis to the lymph nodes and distant organs significantly decreases survival rate [4]. As OSCC is a type of highly malignant tumor with a large capacity to invade locally and metastasize, an approach that decreases invasion and metastasis may facilitate the development of an effective adjuvant therapy [1]. The invasion of tumor cells is a complex, multistage process. It is necessary to identify critical targets in OSCC metastasis such that effective treatments can be developed

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