AIM: To explore the effect of microRNA-146a (miR-146a) on apoptosis of human gastric cancer SGC-7901 cells and the underluing mechanism.METHODS: miR-146a mimic (up-regulated miR-146a expression) and miR-146a inhibitor (down-regulated miR-146a expression) were transfected into the SGC-7901 cells by liposome method.At the same time, miRNA nonsense sequence transfection group as the negative control group (NC group) was set up.RT-qPCR was used to evaluate the levels of miR-146a in the SGC-7901 cells after transfection.The effects of miR-146a on the cell apoptosis and growth were assessed by flow cytometry analysis and CCK-8 assay, respectively.The effect of over-expression or knockdown of miR-146a on transforming growth factor-β-activated kinase 1 (TAK1)/ nuclear factor-kappa B (NF-κB) signaling was evaluated by RT-qPCR and Western blot.RESULTS: miR-146a modulated apoptosis of SGC-7901 cells.Over-expression of miR-146a significantly increased apoptosis, whereas knockdown of miR-146a inhibited the apoptosis of SGC-7901 cells.The expression of TAK1 at mRNA and protein levels was significantly decreased when miR-146a mimic was transfected into the SGC-7901 cells (P<0.05).On the contrast, the expression of TAK1 at mRNA and protein were significantly higher in miR-146a inhibitor transfection group than that in NC group (P<0.05), suggesting that miR-146a negatively regulated TAK1 expression.Moreover, knockdown of TAK1 enhanced the apoptosis of SGC-7901 cells (P<0.01), while over-expression of TAK1 inhibited the apoptosis of SGC-7901 cells(P<0.01).Additionally, both over-expression of miR-146a and knockdown of TAK1 led to a prominent increase in the expression of NF-κB inhibitor protein alpha (IκBα) and a significat decrease in B cell lymphoma-2 (Bcl-2) level in the SGC-7901 cells.CONCLUSION: miR-146a significantly promotes apoptosis of SGC-7901 cells by inhibition of NF-κB pathway via targeting TAK1.%目的: 观察微小RNA-146a (miR-146a)对胃癌SGC-7901细胞凋亡的影响及其可能的分子机制.方法: 将miR-146a mimic(上调miR-146a表达)和miR-146a inhibitor(下调miR-146a表达)分别转染至人胃癌SGC-7901 细胞中,同时设置miRNA 无义序列转染为阴性对照组(NC组).RT-qPCR检测转染后胃癌细胞miR-146a的表达水平;CCK-8法和流式细胞术检测miR-146a对SGC-7901胃癌细胞生长活力和凋亡的影响;RT-qPCR和Wes-tern blot法检测miR-146a上调或下调对转化生长因子β激活激酶1(TAK1)/核因子κB (NF-κB)通路的影响. 结果: 在SGC-7901细胞中,上调miR-146a表达显著促进细胞凋亡,而下调miR-146a表达则显著抑制细胞凋亡.与NC组相比,miR-146a mimics转染SGC-7901细胞后,TAK1的mRNA和蛋白表达均明显下降,差异均有统计学显著性(P<0.05),而miR-146a inhibitors转染组TAK1的mRNA和蛋白质表达则显著增加(P<0.05),提示miR-146a负调控TAK1表达.敲低TAK1促进SGC-7901细胞凋亡(P<0.01),而TAK1过表达TAKI则抑制SGC-7901细胞凋亡(P<0.01).此外,过表达miR-146a和敲低TAK1均能显著上调NF-κB抑制蛋白α(IκBα)和下调B细胞淋巴瘤-2(Bcl-2)表达.结论: 本研究结果表明miR-146a通过靶向TAK1抑制NF-κB途径,从而诱导胃癌细胞凋亡.
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