二氢杨梅素通过抑制mTOR信号通路抑制乳腺癌细胞迁移和侵袭

Dihydromyricetin inhibits migration and invasion of human breast cancer cells by suppressing mTOR signaling pathway

目的探讨二氢杨梅素(dihydromyricetin,DHM)对人乳腺癌细胞迁移和侵袭的抑制作用及其可能的分子机制。方法以不同浓度DHM(0、10、20μmol/L和40μmol/L)处理乳腺癌细胞MDA-MB-231,采用Transwell实验检测DHM对癌细胞迁移和侵袭能力的影响,采用蛋白印迹法检测迁移与侵袭标志蛋白(Snail、vimentin、MMP-2和MMP-9)及抑迁移蛋白E-cadherin表达的变化;同时利用乳腺癌细胞裸鼠移植瘤模型和免疫组织化学检测法,观察DHM膳食干预(100 mg/kg)对体内癌细胞迁移与侵袭相关蛋白表达的影响。结果 DHM处理乳腺癌细胞24 h,与对照组相比,细胞迁移和侵袭能力均显著降低(P<0.05),40μmol/L处理组细胞迁移能力下降至(37.8±3.1)%,侵袭能力下降至(21.4±2.3)%;蛋白表达检测结果显示,DHM处理细胞其Snail、vimentin、MMP-2和MMP-9表达水平显著降低(P<0.01),40μmol/L处理组蛋白表达分别下降至(31.2±2.9)%、(11.1±0.9)%、(14.4±1.2)%、(12.7±1.1)%,而E-cadherin表达水平显著升高(P<0.01),升高至(3.9±0.4)倍;体内研究结果也显示,DHM膳食干预可显著降低移植瘤组织内Snail、vimentin和MMP-9的表达,提高E-cadherin的表达(P<0.01)。进一步研究表明,DHM处理细胞24 h,与对照组相比,细胞内p-mTOR、p-4EBP1、p-S6K70和p-e IF4B表达水平均显著降低(P<0.05),表明其mTOR信号通路被显著抑制。结论 DHM可有效抑制乳腺癌细胞的迁移和侵袭,其机制可能是通过抑制mTOR信号通路实现的。

Objective To investigate the effect of dihydromyricetin（DHM） on the migration and invasion in human breast cancer cells and explore the possible molecular mechanism. Methods Human breast cancer MDA-MB-231 cells were treated with 0,10,20 or 40 μmol/L DHM,and the changes in the migration and invasion of the cells were evaluated using Transwell assay. The expressionlevels of Snail,vimentin,MMP-2,MMP-9 and E-cadherin in the cells were detected by Western blotting. In nude mice bearing MDA-MB-231 cell xenograft,the effect of gastric lavage of 100 mg/kg DHM on the expression levels of these proteins in the tumor was investigated using immunohistochemistry. Results DHM treatment for 24 h effectively inhibited the migration and invasion of breast cancer cells（P 0. 05） with the dose of 40 μmol/L decreasing the migration to（37. 8 ± 3. 1） % and the invasion to（21. 4 ± 2. 3） %. Compared with the control cells,the DHM-treated cells exhibited significantly decreased expression of Snail,vimentin,MMP-2 and MMP-9（P 0. 01） [40 μmol/L decreasing to（31. 2 ± 2. 9） %,（11. 1 ± 0. 9） %,（14. 4 ± 1. 2） % and（12. 7 ± 1. 1） %,repspectively ]and an increased expression of E-cadherin（the dose increasing by 3. 9 ± 0. 4 times）. In the tumor-bearing mice,gastric lavage of DHM significantly down-regulated the expression of Snail,vimentin and MMP-9 and increased the expression of E-cadherin in the cells xenograft（P 0. 01）.Treatment of MDA-MB-231 cells with DHM for 24 h also obviously reduced the phosphorylation of the downstream proteins,including mTOR,4 EBP1,S6 K70 and e IF4 B（P 0. 05）,indicating the suppression of the activation of the mammalian target of rapamycin（mTOR） pathway. Conclusion DHM can significantly inhibit the migration and invasion of breast cancer cells possibly by suppressing the mTOR signaling pathway.