miR-198 regulated the tumorigenesis of gastric cancer by targeting Toll-like receptor 4 (TLR4)

X.-Q. Quan, Z.-L. Xie, Y. Ding, R. Feng, X.-Y. Zhu, Q.-X. Zhang

Department of Histology and Embryology, Basic Medical College of Zhengzhou University, Zhengzhou, Henan, China. qxz53@zzu.edu.cn

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• Oncology

OBJECTIVE: To investigate the role of miR-198 and its target gene Toll-like receptor 4 (TLR4) of tumorigenesis of gastric cancer (GC).

MATERIALS AND METHODS: The expression of miR-198 in GC cells was detected by quantitative polymerase chain reaction (qPCR). The proliferation, apoptosis, migration, and invasion of GC cells were detected by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT), flow cytometry, transwell chamber, and wound scratch assay. Bioinformatics analysis for the results of protein chip was performed to identify the target genes of miR-198. TLR4 was further confirmed to be the target gene of miR-198 by TLR4 luciferase reporter assay.

RESULTS: miR-198 expression level in GC SGC-7901 cells significantly decreased compared with the normal cells. When the miR-198 was overexpressed, the proliferation, migration, and invasion of GC cells were significantly decreased, while the apoptosis was increased. The expression of TLR4 in SGC-7901 cells was significantly higher, while the expression of TLR4 in SGC-7901 cells transfected with miR-198 significantly lowered, which was consistent with the Western blot for TLR4. The luciferase reporter assay confirmed that TLR4 was the target genes of miR-198 in GC SGC7901 cells.

CONCLUSIONS: miR-198 could induce apoptosis and inhibit the proliferation, migration, and invasion of GC cells through downregulating TLR4 expression.

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