PPARγ激活在蛇葡萄素抑制乳腺癌细胞增殖和诱导凋亡中的作用

Role of PPARγ activation in cell growth inhibition and apoptosis inducement by ampelopsin in breast cancer cells

目的探讨过氧化物酶体增殖激活物受体γ(peroxisome proliferators-activated receptorγ,PPARγ)的激活在蛇葡萄素(ampelopsin,AMP)抑制乳腺癌细胞增殖和诱导细胞增殖凋亡中的作用。方法以不同浓度AMP(20、40、60、80μmol/L)分别处理人乳腺癌MDA-MB-231、MCF-7细胞24 h后,荧光素酶报告基因法检测AMP对PPARγ的激活作用,CCK-8检测细胞活力,流式细胞仪检测细胞凋亡,Western blot检测凋亡相关蛋白的表达,Caspase-3活性检测试剂盒检测Caspase-3活性。结果与PPARγ激动剂罗格列酮一样,AMP剂量依赖性地增强报告基因荧光素酶活性,同时显著抑制乳腺癌细胞增殖并诱导细胞凋亡(P<0.05);Western blot检测结果显示,AMP在显著上调乳腺癌细胞凋亡相关蛋白Bax、PTEN、活化Caspase-3表达的同时下调Bcl-2蛋白及Bcl-2/Bax比值;激酶活性检测结果显示,AMP可显著增强Caspase-3激酶活性,以上作用均可被PPARγ特异性拮抗剂GW9662显著削弱。结论AMP可能是PPARγ的天然激动剂,其通过激活PPARγ信号途径抑制乳腺癌细胞增殖并诱导细胞凋亡。

Objective To investigate whether the activation of proliferators-activated receptor γ （PPARγ） is required for ampelopsin （AMP）-induced cell growth inhibition and apoptosis in human breast cancer cells. Methods After different concentrations of AMP （20, 40, 60 and 80 μmol/L） was used to treat breast cancer cell lines MCF-7 and MDA-MB-231 for 24 h respectively, PPAR7 activity was measured by luciferase reporter assay, cell viability was assessed by CCK-8 assay, and cell apoptosis was measured by flow cytometry with Annexin V-FITC/PI staining. Western blotting was used to measure the expression of apoptosis related proteins, and a clorimetric assay kit was employed to detect Caspase-3 activity. Results As PPARγ agonist rosiglitazone, AMP treatment also enhanced the activity of luciferase reporter, inhibited cell viability and induced apoptosis （P 〈 0. 05 ） in MCF-7 and MDA-MB-231 cells in dose-dependent manners. Furthermore, Western blotting showed that AMP significantly up-regulated apoptosis related proteins Bax and PTEN, activated Caspase-3, down-regulated Bcl-2 and decreased the ratio of Bcl-2/Bax. Clorimetric assay indicated that the treatment enhanced the activity of Caspase-3. All above results could be obviously attenuated by PPARγ specific antagonist GW9662. Conclusion AMP maybe a natural agonist of PPARγ, and it can suppress cell proliferation and induce apoptosis in breast cancer cells by activating PPARγ.