Mir-342-3p Inhibits The Proliferation Of Liver Cancer Cells By Negatively Regulating MAFG/FOXM1/DNMT1

Objective: miR-342-3p expression is significantly down-regulated in hepatocellular carcinoma(HCC).However,the specific molecular mechanism has not been clarified.Predicated miR-342-3p binding sites within MAFG,FOXM1 and DNMT1 3’UTR by Target Scan.The expression of MAFG,FOXM1 and DNMT1 is significantly up-regulated in HCC tissues.Hence,this research is aimed to explore the role of miR-342-3p regulating MAFG,FOXM1 and DNMT1 in liver cancer by collecting human HCC specimens and adjacent benign tissues from patients and culturing HCC cell lines in vitro.Methods: 1.HCC specimens and adjacent benign tissues were observed by hematoxylin-eosin(HE)staining.Immunohistochemical method and Western blot analysis were used to detect the protein expression levels of MAFG,FOXM1,DNMT1,PCNA and MMP9.q RT-PCR was analyzed the m RNA expression levels of miR-342-3p,MAFG,FOXM1,DNMT1,PCNA and MMP9.Expression analysis of miR-342-3p,MAFG,FOXM1,DNMT1,PCNA and MMP9 in HCC specimens and adjacent benign tissues by the databases were downloaded from expression database GEO.Correlation between the expression levels of MAFG,FOXM1,DNMT1,PCNA and MMP9 in HCC tissues were analyzed by Pearson’s correlation coeffcients.Kaplan-Meier survival analysis showed the correlation between gene expression level and prognosis with cancer patients.2.HCC cell lines were cultured in vitro to detect the expression of miR-342-3p.Then,q RT-PCR analysis of miR-342-3p,MAFG,FOXM1,DNMT1,PCNA and MMP9 m RNA expression levels and Western blot analysis MAFG,FOXM1,DNMT1,PCNA and MMP9 protein expression levels in the Hep G2 cells transfected with miR-342-3p mimics or miR-342-3p inhitors.q RT-PCR analysis of miR-342-3p,MAFG,FOXM1,DNMT1,PCNA and MMP9 m RNA expression levels and Western blot analysis MAFG,FOXM1,DNMT1,PCNA and MMP9 protein expression levels in the Hep G2 cells were used to silence MAFG,FOXM1 and DNMT1.q RT-PCR analysis of miR-342-3p,MAFG,FOXM1,DNMT1,PCNA and MMP9 m RNA expression levels and Western blot analysis MAFG,FOXM1,DNMT1,PCNA and MMP9 protein expression levels in the Hep G2 cells added FOXM1 inhibitors FDI-6 or DNMT1 inhibitors 5-Aza-Cd R.MTT assy was used to determine the proliferation of cells.Results: 1.The result of HE staining showed that compared with the adjacent tissues,there was no disorder in the morphology and arrangement of intact cells in liver cancer tissues.The results of IHC showed that MAFG,FOXM1,DNMT1,and PCNA locate mainly in the nucleus,MMP9 locates in the cytosol,levels of MAFG,FOXM1,DNMT1,PCNA and MMP9 were increased in human HCC tissues compared with non-tumor tissues.the m RNA expression level of miR-342-3p was lower in HCC tissues.The expression of miR-342-3p was significantly decreased in the databases of GSE115019,GSE54751,GSE21362,and GSE67138,while MAFG,FOXM1,DNMT1,PCNA and MMP9 were highly expressed in databases of GSE14520 and GSE102079.The expression levels of MAFG,FOXM1,DNMT1,PCNA or MMP9 were positively correlated.Kaplan-Meier survival analysis further showed that the survival time of liver cancer patients with high expression of MAFG,FOXM1,DNMT1,PCNA and MMP9 was significantly shortened in patients with low expression.Kaplan-Meier survival analysis further showed that the survival time of liver cancer patients with high expression of MAFG,FOXM1,DNMT1,PCNA and MMP9 were shorter than that of patients with low expression 2.Hep G2 cells transfected with miR-342-3p mimics,the expression of miR-342-3p was increased,while the expression of MAFG,FOXM1,DNMT1,PCNA and MMP9 were decreased,Hep G2 cells transfected with miR-342-3p inhibitors,the expression of miR-342-3p was decreased,while the expression of MAFG,FOXM1,DNMT1,PCNA and MMP9 were increased.Silencing MAFG down-regulated the expression of FOXM1,DNMT1,PCNA and MMP9.After silencing FOXM1,the expression of DNMT1,PCNA and MMP9 decreased.After silencing DNMT1,the expression of PCNA and MMP9 decreased.MTT showed that the proliferation of Hep G2 cells were significantly inhibited by silencing MAFG,FOXM1,DNMT1 and adding FDI-6,5-Aza-Cd R.transfering miR-342-3p mimic,while promoted the proliferation of Hep G2 cells by transfering miR-342-3p inhibitor.Conclusion: miR-342-3p inhibits the proliferation of liver cancer cells by negatively regulating MAFG/FOXM1/DNMT1.