Upregulated Expression Of MiR-106a By DNA Hypomethylation Plays An Oncogenic Role In Hepatocellular Carcinoma

Objective: Aberrant mi RNA expression has been widely recognized to play an extremely important role in several cancers, including hepatocellular carcinoma(HCC). According to the previous studies, abnormal mi R-106 a expression was closely related to various cancers occurrence. However, the mi R-106 a expression in HCC remains unclear. Our study sought to focus on the mi R-106 a as a potential diagnostic and prognostic biomarker in HCC and explored the mechanism of mi R-106 a transcriptional activation and the possible target gene in HCC and the functions of mi R-106 a in HCC cells in vitro.Methods: Firstly, we examined the expression of mi R-106 a in Thirty-five pairs of samples of HCC tissues and HCC cell lines by using q RT-PCR, then investigated the Cp G island methylation status of the mi R-106 a promoter region in the cell lines using BSP, to estimate whether the overexpression of mi R-106 a was associated with the hypomethylation of mi R-106 a promoter. We further compared the methylation status of mi R-106 a promoter region between the HCC cell lines that was treated with 5-Aza and untreated cell line by BSP assay. At the same time, we used dual-luciferase reporter assay to predict the potential functional target genes of mi R-106 a. Finally, the effects of mi R-106 a on cell invasion, apoptosis, proliferation and cell cycle progression, were also investigated.Results: The results of q RT-PCR showed that mi R-106 a expression in HCC tissues was apparently higher than the level in the adjacent tissues. q RT-PCR and BSP to analyze mi R-106 a expression and promoter methylation in HCC cell lines, there came to a conclusion that the methylation status of the mi R-106 a promoter region was inversely correlated with the expression of mi R-106 a. After prediction with online software, we further used dual-luciferase reporter gene assay to ensure that TIMP2, TP53INP1 and CDKN1 A might be the direct targets. After exploring the functions of mi R-106 a in HCC cells in vitro, our results manifested that high-mi R-106 a cell line had stronger invasiveness, more resistance to apoptosis, more active proliferation and faster cell cycle progression compared with the low-mi R-106 a cell line.Conclusions: In this study, we firstly demonstrated that mi R-106 a expression was increased in HCC tissues, the methylation status of the mi R-106 a promoter region was inversely correlated with the expression of mi R-106 a. TIMP2, TP53INP1 and CDKN1 A might be the possible direct target genes. At the same time, HCC cell line with overexpression of mi R-106 a exhibited a characteristic of stronger invasion, anti-apoptosis, more active proliferation and faster cell cycle progression. All these results suggested that mi R-106 a might be used as an efficient candidate biomarker and a potential therapeutic target for HCC.