MiR-451a Inhibited Cell Proliferation and Enhanced Tamoxifen Sensitive in Breast Cancer via Macrophage Migration Inhibitory Factor

Zhenru Liu,Zhouhua Jiang,Hong Li,Liming Zhou,Ting Feng,Tianyu Miao,Mingyuab Li

doi:10.1155/2015/207684

Abstract

This study aims to investigate the regulative effects of microRNA-451a (miR-451a) on cell proliferation and sensitivity to tamoxifen in breast cancer cells. In cell culture experiments, the lentiviral vectors of pHBLV-miR-451a and pHBLV-miR-451a sponge were constructed and used to transfect MCF-7 and LCC2 cells. The transfection efficiency was tested by fluorescent observation, and cell lines with stable over- or downregulated expression of miR-451a were established. The expression of miR-451a and the target gene macrophage migration inhibitory factor (MIF) were detected by real-time reverse transcriptase polymerase chain reaction and/or western blot. Moreover, MTT assay, colony formation, and Transwell invasion assays were also performed. Data showed that the recombinant lentiviral vectors were constructed correctly, and the virus titer was 1 × 108 CFU/mL. The stable transfected cells were obtained. Overexpression of miR-451a downregulated MIF expression in mRNA and protein levels and inhibited cell proliferation, colony formation, and invasion of breast cancer cells. Downregulation of miR-451a upregulated MIF expression and increased breast cancer cell growth, invasion, and tamoxifen sensitivity. In summary, the miR-451a/MIF pathway may play important roles in the biological properties of breast cancer cells and may be a potential therapeutic target for breast cancer.

Highlights

MicroRNAs are noncoding small RNAs (19–25 ribonucleotides) that can regulate gene expression at transcriptional and posttranscriptional levels by binding to the 3󸀠untranslated regions (3󸀠UTRs) of target mRNA [1]. miRNAs have been reported to be involved in a range of biological processes, including cell proliferation and apoptosis
ZsGreen was expressed after MCF-7 and LCC2 cells were transduced with the lentivirus
A number of studies showed that migration inhibitory factor (MIF) expression was upregulated in various tumors, which can promote cell proliferation and invasion and correlate with worse survival prognosis [19]

Summary

Introduction

MicroRNAs (miRNAs) are noncoding small RNAs (19–25 ribonucleotides) that can regulate gene expression at transcriptional and posttranscriptional levels by binding to the 3󸀠untranslated regions (3󸀠UTRs) of target mRNA [1]. miRNAs have been reported to be involved in a range of biological processes, including cell proliferation and apoptosis. MicroRNAs (miRNAs) are noncoding small RNAs (19–25 ribonucleotides) that can regulate gene expression at transcriptional and posttranscriptional levels by binding to the 3󸀠untranslated regions (3󸀠UTRs) of target mRNA [1]. MiRNAs have been reported to be involved in a range of biological processes, including cell proliferation and apoptosis. Altered miRNAs expressions were likely to contribute to human diseases including cancers [2]. Previous studies have demonstrated that miR-451a inhibited cell growth and proliferation and enhanced the activity of anticancer drugs [5, 6]. Macrophage migration inhibitory factor (MIF) is a proinflammatory cytokine that is involved in carcinogenic transformation and cancer development. The MIF levels are increased in a number of cancers including breast cancer and contribute to the survival and homeostasis control of cancer cells [7]

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