罗格列酮下调肺腺癌细胞血管内皮细胞生长因子的表达

Down-regulation of vascular endothelial growth factor by Rosiglitazone in human lung adenocarcinoma cells

目的探讨过氧化物酶增殖物活化受体γ(PPARγ)配体罗格列酮(RSG)对肺腺癌血管内皮细胞生长因子(VEGF)表达的调节作用,旨在进一步揭示PPARγ抑制肺腺癌血管生成的机制。方法体外培养人肺腺癌细胞株A549,给予不同浓度RSG作用24 h后,用免疫细胞化学检测VEGF蛋白的表达;逆转录聚合酶链反应(RT-PCR)检测PPARγ、VEGF mRNA的表达。结果RT-PCR及免疫细胞化学结果显示A549细胞存在PPARγmRNA和蛋白的表达。RSG呈浓度依赖方式上调PPARγ的表达;1.25μmol.L-1RSG处理组VEGF mRNA表达明显下调,10μmol.L-1RSG下调作用最强,≥20μmol.L-1RSG下调作用减弱,100μmol.L-1RSG对VEGF mRNA表达下调与对照组比较无统计学意义;PPARγ阻断剂GW 9662明显减弱了RSG下调VEGF的作用(P<0.01或P<0.05,n=6)。结论PPARγ的活化可抑制肺腺肿瘤新生血管的生成,其机制可能是通过部分PPARγ途径下调VEGF的表达而实现的。提示PPARγ可能是肺腺癌血管生成治疗的1个新分子靶点。

Aim To explore the role of a peroxisome proliferators-activated receptor gamma ligand, Rosiglitazone ,in angiogenesis in human lung adenocarcinoma cells with reference to the regulation of vascular endothelial growth factor （VEGF）. Methods Human lung adenocarcinoma A549 cell line was cultured in vitro. Expression of PPARγ and VEGF in A549 lung adenocarcinoma cells treated with different concentrations of Rosiglitazone was examined by semi-quantitative RTPCR and immunohistochemical staining. Results PPARγ protein levels were higher in cultured A549 cells. RT-PCR and immunohistochemical staining showed that PPARγ mRNA and protein were enhanced in cells treated with Rosiglitazone in a dose-ependent manner, compared with those of untreated cells. Rosiglitazone had a potent inhibitory effect on the expres-sion of VEGF in A549 cells dose-dependently in a range of concentrations. The effect was maximal with 10 μmol · L^-1 RSG and weaken over 20 μmol · L^-1 RSG, whereas 100 μmol · L^-1 RSG didnot have this down-regulation. GW9662, a PPARγ antagonist, partially blocked this effect of Rosiglitazone. Conclusions Activation of PPARγ suppresses angiogenesis in human lung adenocarcinoma. This action is probably associated with the down-regulation of angiogenic factor, VEGF, which may be modulated by PPARγ. These resuits suggest that PPARγ might be a novel molecular target for angiogenesis lung adenocarcinoma.