The Effect Of Up-regulating MicroRNA-124 Expression On Apoptosis Of Thyroid Carcinoma Cells And Its Mechanism

Incidence of thyroid caner has continuously increased in the last three decades globally.A similar trend of thyroid cancer incidence appeared in China.New cases and deaths of thyroid cancer in China accounted for 15.6%and 13.8%of the global new cases and deaths in 2012.MicroRNAs are a class of endogenous,short(19-22 nucleotides),noncoding RNA molecules that function as critical gene regulators.In human cancers,miRNAs are frequently located in genomic breakpoint regions and can function as tumor suppressor genes or oncogenes during tumor development and progression.In this study,we investigated the effect of up-regulating microRNA-124 expression on apoptosis of thyroid carcinoma cells and its mechanism.Objective:To investigate the effect of up-regulating miR-124 expression on apoptosis of thyroid carcinoma cells and its mechanism.Methods:The expressions of miR-124 in normal thyroid Nthy-ori3-1 cells and papillary thyroid carcinoma SW579 cells were detected by real-time quantitative PCR(qRT-PCR).The expression of miR-124 was up-regulated by transfecting Hsa-miR-124 mimics with liposomes,and the transfection efficiency was detected by qRT-PCR.The effect of miR-124 expression on apoptosis of SW579 cells was detected by flow cytometry.The effect of overexpression of miR-124 on the expression of phosphatidylinositol-3-kinase catalytic subunit alpha(PIK3CA)protein,ro kinase B(AKT)protein,phosphorylated protein kinase B(p-AKT)protein,B cell lymphoma/leukemia-2(Bcl-2)protein and Bcl-2 X protein(Bax)in the SW579 cells were detected by Western blot.Results:The expression of miR-124 in thyroid carcinoma SW579 cells was significantly lower than that in normal thyroid Nthy-ori3-1 cells(P<0.05).After transfection of Hsa-miR-124 mimics,the expression of miR-124 in miR-124 analog group was significantly higher than that in blank control group(P<0.05),and there was no significant difference between negative control group and blank control group(P>0.05).Flow cytometry results showed that compared with the control group,the apoptosis rate of miR-124 analog group increased significantly,and the difference was statistically significant(P<0.05),but there was no significant difference between the negative control group and the blank control group(P>0.05).Western blot results showed that compared with the control group,the expression of PIK3CA,p-AKT and Bcl-2 protein in miR-124 analog group decreased significantly,and the expression of Bax protein increased significantly,which difference were statistically significant(P<0.05),but the expression of AKT protein was not obvious(P>0.05);There was no significant difference in the expression of PIK3CA,AKT,p-AKT,Bcl-2 and Bax between the negative control group and the blank control group(P>0.05).Conclusion:Up regulation of miR-124 expression can induce apoptosis of SW579 cells,and its mechanism may be related to the inhibition of phosphatidylinositol3-kinase(PI3K)/AKT signaling pathway activity,up regulation of Bax protein expression and down regulation of Bcl-2 protein expression.