Over-expression of miR-187 inhibited cell proliferation and metastasis of glioma via down-regulating SMAD1

A.-J. Gulinaer, A.-N. Ju, M. Gao, Y. Luo, Y.-L. Bo

Department of Pathology, The First Affiliated Hospital of Xinjiang Medical University, Urumqi, China. docylbo@163.com

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• Oncology

OBJECTIVE: MicroRNAs (miRNAs) have been identified to participate in the tumorigenesis and progression of glioma. However, the expression and function of miR-187 have not been fully elucidated in glioma so far. Therefore, the aim of this study was to investigate the role of miR-187 in glioma and to explore the possible underlying mechanism.

PATIENTS AND METHODS: The expression levels of miR-187 in 67 glioma tissues and 21 normal brain tissues, as well as 4 glioma-derived cell lines were measured using quantitative Real Time-Polymerase Chain Reaction (qRT-PCR). MiR-187 was overexpressed or inhibited in U251 or U87MG cells using miR-187 mimics or inhibitor transfection, respectively. Colony formation assay and Cell Counting Kit-8 (CCK-8) assay were employed to detect the proliferation ability of cells. Meanwhile, transwell assay and wound-healing assay were applied to evaluate the invasion and migration capacities of cells. Furthermore, Dual-Luciferase assay and Western blot analysis were used to verify the downstream target gene of miR-187 in glioma.

RESULTS: MiR-187 expression was significantly lower in glioma tissues and cells when compared with normal brain tissues and cell lines. Up-regulation of miR-187 markedly reduced the proliferation, migration and invasion of U251 cells compared with the negative control group. However, down-regulation of miR-187 remarkably accelerated U87MG cell growth and metastasis compared with inhibitor negative control group. Furthermore, SMAD1 was identified as a direct target for miR-187 in glioma, which could be repressed by miR-187. In addition, over-expression of SMAD1 restored the influence of miR-187 mimics in glioma cells.

CONCLUSIONS: MiR-187 was lowly expressed in glioma tissues and cell lines. Acting as a tumor suppressor, miR-187 inhibited cell growth, invasion, and migration in glioma via repressing SMAD1 expression. Our findings might provide a novel insight into the biological diagnosis and treatment in glioma.

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