The Mechanisms Of MiR-134 And LXR In Suppressing The Proliferation Of Hepatocellular Carcinoma Cells

Background:Hepatocellular carcinoma(HCC)is a common malignant tumor with high morbidity、high mortality and unsatisfactory prognosis.So,clarifing the development mechanism of HCC and looking for new target genes of HCC treatment is significant.In recent years,more and more attention is paied on the noncoding RNA related to tumor,including of mi RNA and lncRNA.Mi RNA is closely involved in regulating the tumor development by regulating some tumor target genes to promote or repress cancer development.As reported,there are multiple mi RNAs that are closely involved in HCC development.And miR-134 is an important cancer suppressor and can suppress the proliferation and metastasis of HCC.But the mechanism of the suppression still needs further elaboration.The abnormal expression of lnc RNA is also associated with the development 、the metastasis and the prognosis of tumor.HULC,an lncRNA specifically expresses in HCC with a high level,is participate in the development and metastasis of HCC.So effectively suppressing the expression and function of HULC will undoubtedly help to find new strategies for HCC treatment.LXR is one important part of the nuclear receptor superfamily with significant anti-HCC effect.But there is no report about whether LXR can suppress the development of hepatocellular carcinoma by regulating HULC.So the subject of our study is to investigate the role and mechanism of mi R-134 in anti-HCC by regulating the gene FOXM1 associated with tumor proliferation,and to detect the role and mechanism of LXR in suppressing the proliferation of HCC by regulating lncRNA HULC.Then it can help to accumulate new theoretical datas of HCC development and to explore new target genes of HCC preventment and controlling.Objective:To investigate the roles and the mechanisms of miR-134 and LXR in suppressing the proliferation of hepatocellular carcinoma cells.Content and method:1.CCK-8 assay was used to detect the effect of mi R-134 on the proliferation of hepatocellular carcinoma cells(HCC).2.Western blot and Real-time PCR were separately performed to examine the expression of FOXM1 and mature mi R-134 in five human HCC cell lines and hepatic cell L02.And then the relationship between the two was analyzed by Pearson ’s correlation analysis.3.After transfecting with miR-134 mimic or miR-134 inhibitor in HCC cells,the levels of FOXM1 and its target gene Cyclin D1 were measured by Western blot and Real-time PCR.4.Predict the potential binding site of mi R-134 on FOXM1 3′-UTR and structure the reporter plasmids,then the luciferase reporter assays were used to analyze the specific binding of miR-134 with FOXM1 3′-UTR.5.Co-transfect HCC cells with mi R-134 mimic and FOXM1-expressing plasmids,and then the proliferation of the cells was assessed by CCK-8 assay again.6.CCK-8 assay was performed to detect the effect of LXR on the proliferation of hepatocellular carcinoma cells(HCC).7.After being dealing with LXR agonists,the level of HULC in HCC was measured by Real-time PCR.8.After over-expressing HULC,the proliferation of the cells was assessed by CCK-8 assay again.Result:1.miR-134 could dramatically inhibit the proliferation of HCC cells.2.HCC cell lines had a lower expression of mi R-134 and a higher level of FOXM1 protein,there was a significant inverse correlation between miR-134 and FOXM1 protein level.3.mi R-134 repressed the expression of FOXM1 protein and its target gene CyclinD1 by specifically binding to FOXM1 3′-UTR.4.Over-expressing FOXM1 attenuated the miR-134-mediated suppression of the proliferation of HCC cells.5.LXR could inhibit the proliferation of HCC cells,and over-expressing HULC would attenuate the suppression.6.LXR could dramatically repress the expression of HULC.Conclusion:1.mi R-134 downregulates FOXM1 protein level and its target gene CyclinD1 by directly targeting to FOXM1 3′-UTR,and subsequently inhibits the proliferation of hepatocellular carcinoma cells.2.LXR suppresses the proliferation of hepatocellular carcinoma cells by downregulating HULC,but the specific regulatory mechanism still needs further study.