MiR-146a And MiR-146b Promote Proliferation,Migration And Invasion Of Follicular Thyroid Carcinoma Via Inhibition Of ST8SIA4

Objective: The objective of this study is to analyze the differential expression of 6alpha-2,8-sialyltransferase genes in the both human follicular thyroid carcinoma(FTC)cell lines and tissue specimens of FTC patients,and to clarify the potential mechanism of based on miR-146a/b probe in modulating the proliferation,migration and invasion of follicular thyroid carcinoma cell by targeting ST8SIA4.To better diagnose human follicular thyroid carcinoma,and provide a possible modern molecular target point of FTC.Methods:(1)We detected the expression of members of the ST8 SIA gene family in two FTC cell lines with different invasive potentials(FTC-133 and FTC-238)and the human thyroid epithelial cell line Nthy-ori 3-1.We also explored the expression of the ST8 SIA gene family in FTC tissue and normal thyroid tissue.(2)We detected whether the downregulation or overexpression of ST8SIA4 mediates the proliferation,migration and invasion of FTC cells both in vitro and in vivo.(3)We searched for potential targets of ST8SIA4 using the bioinformatics algorithms TargetScan(http://www.targetscan.org),miRanda(http://www.microrna.org/microrna/home.do)and mirbase(http://www.Mirbase.org).Additionally,we identified several miRNAs that may target ST8SIA4,which upregulated in thyroid cancer(data not shown).miR-146 a and miR-146 b were chose as the most probable candidates.Further validation of miR-146 a and miR-146 b targeting ST8SIA4 byluciferase reporter system.We used q-PCR to detect the different expression of miR-146 a and/or miR-146 b in two FTC cell lines and Nthy-ori 3-1 cell lines,and also in the FTC tissue and normal thyroid tissue.By constructing miR-146 a and/or miR-146 b mimics or antagomir oligonucleotide,we analysis its regulation of ST8SIA4.(4)After downregulating or upregulating miR-146 a and/or miR-146 b,we detected the proliferation,migration and invasion of FTC cell both in vitro and in vivo.(5)We rescued ST8SIA4 expression in the miR-146a/b-overexpressing FTC-133 cells and suppressed ST8SIA4 expression in the mi R-146a/b-inhibited FTC-238 cells,then we detected the proliferation,migration and invasion of FTC cell both in vitro and in vivo.(6)The different expressions of PI3K-AKT-m TOR pathway which regulated by miR-146a/b and ST8SIA4 in FTC cells were examined by Western blot.Result:(1)The expression of ST8 SIA was significantly different between the two groups of human FTC cell lines and tissues.(2)The downregulation of ST8SIA4 in FTC-133 cell promoted proliferation,migration,and invasion of FTC-133 cells(*P < 0.05),while the upregulation of ST8SIA4 in FTC-238 cells suppressed proliferation,migration,and invasion of FTC-238 cells(*P < 0.05).(3)The different expressions of miR-146 a and/or mi R-146 b were significant in FTC-133,FTC-238 and Nthy-ori 3-1 cell lines,and also in FTC and normal thyroid tissue samples from patients.The special regulation of miR-146 a and/or miR-146 b mediated ST8SIA4.(4)Downregulation of miR-146 a and/or mi R-146 b in FTC-238 cells decreased the proliferation,migration,and invasion of FTC-238 cells,and increased the expression level of ST8SIA4;Upregulation of mi R-146 a and/or miR-146 b in FTC-133 cells decreased the proliferation,migration,and invasion of FTC-133 cells in vivo and in vitro,and decreased the expression level of ST8SIA4.(5)We rescued ST8SIA4 expression in the miR-146a/b-overexpressing FTC-133 cells,and found that ST8SIA4 restoration decreased the proliferation,migration and invasion of miR-146a/b-overexpressing FTC-133 cells.We suppressed ST8SIA4 expression in the miR-146a/b-inhibited FTC-238 cells,and found that ST8SIA4 suppression partially increased the proliferation,migration and invasion capacity of miR-146a/b-inhibited FTC-238 cells.(6)Upregulation of mi R-146a/b in FTC-133 cells increased the expression of PI3K-AKT-mTOR signaling pathway,and upregulation of ST8SIA4 can reverse the effect of miR-146a/b upregulation;Downregulation of miR-146a/b in FTC-238 cells decreased the expression of PI3K-AKT-mTOR signaling pathway,and downregulation of ST8SIA4 can reverse the effect of miR-146a/b downregulation;Conclusion:(1)The expression of ST8 SIA genes was completely difference in two FTC cell lines and Nthy-ori 3-1 cell lines,and also in the FTC tissue and normal thyroid tissue.ST8SIA4 inhibited the proliferation,migration and invasion of FTC both in vitro and in vivo.(2)miR-146 a and miR-146 b promote the proliferation,migration and invasion of FTC via the inhibition of ST8SIA4.