熊果酸通过AMPK/STAT3/COX-2信号通路抑制胃癌细胞增殖

Ursolic Acid Inhibits Gastric Cancer Cells Proliferation through AMPK/STAT3/COX-2 Signaling Pathway

背景:前期研究发现,熊果酸通过下调环氧合酶2(COX-2)表达抑制胃癌细胞增殖,但熊果酸抑制COX-2表达的分子机制尚未完全明确。目的:探讨单磷酸腺苷活化蛋白激酶(AMPK)/信号转导与转录活化因子3(STAT3)/COX-2信号通路在熊果酸抑制胃癌细胞增殖中的作用。方法:构建AMPK-pLVX、AMPK-shRNA、STAT3-pLVX、STAT3-shRNA质粒,分别转染胃癌细胞株SGC-7901和MKN-45,并给予不同浓度或不同培养时间的熊果酸进行培养。以蛋白质印迹法检测磷酸化AMPK、磷酸化STAT3和COX-2表达,CCK-8法检测胃癌细胞增殖。结果:在SGC-7901和MKN-45细胞中,熊果酸呈剂量和时间依赖性地促进AMPK磷酸化、抑制STAT3磷酸化和COX-2表达。敲除AMPK基因能阻断熊果酸抑制STAT3磷酸化和COX-2表达的作用,过表达STAT3基因能逆转熊果酸抑制COX-2表达的作用。敲除AMPK基因和过表达STAT3基因均可逆转熊果酸抑制胃癌细胞增殖的作用。结论:熊果酸可能通过AMPK/STAT3通路下调COX-2表达而抑制胃癌细胞增殖。

Previous study has found that ursolic acid （UA） inhibited the proliferation of gastric cancer cells by the down-regulation of cyclooxygenase-2 （COX-2） expression. However, its molecular mechanism is not fully clear. Aims ： To investigate the role of adenosine monophosphate-activated protein kinase （AMPK）/signal transducer and activator of transcription 3 （STAT3）/COX-2 signaling pathway in UA-mediated inhibition of gastric cancer cells proliferation. Methods： AMPK-pLVX, AMPK-shRNA, STAT3-pLVX, STAT3-shRNA plasmids were constructed, and then were transfected into human gastric cancer cell lines SGC-7901 and MKN-45, respectively. Gastric cancer cells were cultured with different concentrations of UA for different times. The expressions of phosphorylated AMPK （p-AMPK）, phosphorylated STAT3 （p-STAT3） and COX-2 were measured by Western blotting, and cell proliferation was detected by CCK-8 assay. Results： UA dose- and time-dependently increased p-AMPK expression, inhibited p-STAT3 and COX-2 expressions in SGC-7901 and MKN-45 cells. Knockdown of AMPK blocked UA-indueed inhibition of STAT3 phosphorylation and COX-2 expression. Overexpression of STAT3 blocked UA-induced down-regulation of COX-2 expression. Knockdown of AMPK and overexpression of STAT3 blocked UA-induced inhibition of proliferation of gastric cancer cells. Conclusions： UA may inhibit the proliferation of gastric cancer cells via down-regulation of COX-2 expression through AMPK/STAT3 pathway.