MicroRNA-124 Inhibits Migration and Invasion by Down-Regulating ROCK1 in Glioma

Liwen An,Yongjun Liu,Anhua Wu,Yifu Guan,Svetlana Kotliarova

doi:10.1371/journal.pone.0069478

Abstract

BackgroundThe extraordinary invasive capability is a major cause of treatment failure and tumor recurrence in glioma, however, the molecular and cellular mechanisms governing glioma invasion remain poorly understood. Evidence in other cell systems has implicated the regulatory role of microRNA in cell motility and invasion, which promotes us to investigate the biological functions of miR-124 in glioma in this regard.ResultsWe have found that miR-124 is dramatically downregulated in clinical specimen of glioma and is negatively correlated with the tumor pathological grading in the current study. The cells transfected by miR-124 expression vector have demonstrated retarded cell mobility. Using a bioinformatics analysis approach, rho-associated coiled-coil containing protein kinase 1 (ROCK1), a well-known cell mobility-related gene, has been identified as the target of miR-124. A dual-luciferase reporter assay was used to confirm that miR-124 targeted directly the 3′UTR of ROCK1 gene and repressed the ROCK1 expression in U87MG human glioma cell line. Furthermore, experiments have shown that the decreased cell mobility was due to the actin cytoskeleton rearrangements and the reduced cell surface ruffle in U87MG glioma cells. These results are similar to the cellular responses of U87MG glioma cells to the treatment of Y-27632, an inhibitor of ROCK protein. Moreover, a constitutively active ROCK1 in miR-124 over-expressed glioma cells reversed the effects of miR-124. Our results revealed a novel mechanism that miR-124 inhibits glioma cells migration and invasion via ROCK1 downregulation.ConclusionsThese results suggest that miR-124 may function as anti-migration and anti-invasion influence in glioma and provides a potential approach for developing miR-124-based therapeutic strategies for malignant glioma therapy.

Highlights

Brain tumors account for,90% of all primary central nervous system tumors
We found that co-transfection of miR-124 expression vector along with the full-length 39-untranslated regions (39UTR) of rho-associated coiled-coil containing protein kinase 1 (ROCK1) caused a significant decrease by over 50% in luciferase units compared to controls (Figure 3D)
We used Y-27632 to treat U87MG cells, and observed that the diminished density and looser structure of the actin meshwork in U87MG glioma cells and the reduced protrusion by scan electron microscopy. All these results were similar to our in vitro observations in miR-124 overexpressioned cells, (Figure 5C). These results suggest that the anti-invasion effects of indicating a potential role of ROCK1 in glioma cell invasion. miR-124 are in part facilitated by ROCK1 downregulation

Summary

Introduction

Brain tumors account for ,90% of all primary central nervous system tumors. Gliomas are the most common type of malignant primary brain tumor, accounting for 80% of malignant case [2,3]. Due to its high invasive neoplasm infiltrating diffusely into regions of normal brain, glioma is extremely difficult to be cured by total surgical resection or radiotherapy, leading to a high recurrences and poor prognosis. Despite of multi-modality treatment, the median survival of patients suffering from malignant glioma such as glioblastoma multiforme (GBM) is only 12 to 15 months [4]. It is urgently needed to understand the mechanisms of glioma cell’s migration and invasion and develop more effective curative therapies. The extraordinary invasive capability is a major cause of treatment failure and tumor recurrence in glioma, the molecular and cellular mechanisms governing glioma invasion remain poorly understood. Evidence in other cell systems has implicated the regulatory role of microRNA in cell motility and invasion, which promotes us to investigate the biological functions of miR-124 in glioma in this regard

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Results

Discussion

Conclusion