新藤黄酸体外抗肺癌血管生成的作用机制研究

Mechanism of gambogenic acid in resisting angiogenesis of lung cancer in vitro

为了观察新藤黄酸(gambogenic acid,GNA)对肺癌血管生成的影响及初步的作用机制。该实验以新藤黄酸处理肺腺癌A549细胞的条件培养基培养人脐静脉内皮细胞(HUVEC),建立非直接接触型细胞共培养体系;应用Matrigel胶建立HUVEC的二维培养模型,观察新藤黄酸对血管生成的影响;DAPI染色倒置荧光显微镜下观察新藤黄酸对HUVEC细胞凋亡的影响;Annexin V-FITC/PI染色流式细胞术分析新藤黄酸对HUVEC凋亡率的影响;Western blot法检测新藤黄酸对HUVEC中PI3K,p-PI3K,Akt,p-Akt,VEGF蛋白表达的影响;采用PTEN-siRNA转染细胞后,RT-PCR法检测PI3K,Akt基因的表达水平。结果表明,新藤黄酸能明显抑制血管生成,其抑制效果与剂量相关;DAPI染色荧光显微镜下可见HUVEC可出现凋亡形态特征;Annexin V-FITC/PI染色流式细胞术检测结果显示新藤黄酸诱导HUVEC细胞凋亡;Western blot法检测结果表明新藤黄酸下调了p-PI3K,p-Akt蛋白的表达水平,而对PI3K,Akt蛋白表达影响不明显。RT-PCR法检测表明PTEN-siRNA转染入细胞后,能上调PI3K,Akt mRNA基因的表达。体外研究表明新藤黄酸能抑制肺癌血管生成,抑制血管生成的机制可能与PI3K/Akt信号通路有关。

The aim of this paper was to observe the effect of gambogenic acid on angiogenesis of lung cancer and its preliminary mechanism. After culturing lung adenocarcinoma A549 cells, the conditioned medium was treated with gambogenic acid and then used to culture human umbilical vein endothelial cells(HUVECs) to establish the indirect contact cell co-culture system. A two-dimensional culture model of HUVEC was established with matrigel to observe the effect of gambogenic acid on angiogenesis. DAPI staining was used to observe the morphological changes in HUVEC cells after treatment with gambogenic acid under the fluorescence microscope. Annexin V-FITC/PI staining and flow cytometry analysis were used to determine gambogenic acid′s effect on HUVEC cell apoptosis rate. The protein expressions of PI3 K, p-PI3 K, Akt, p-Akt were measured by Western blot. PTEN-siRNA was transfected into cells, and RT-PCR was used to detect the expression levels of PI3 K and Akt genes. Gambogenic acid can significantly inhibit angiogenesis, and its inhibitory effect was dose-dependent. DAPI staining showed apoptotic morphological features of HUVEC cells under fluorescence microscope. Annexin V-FITC/PI staining showed that gambogenic acid induced apoptosis in HUVECs. The results of Western blot showed that the expressions of p-PI3 K and p-Akt protein were down-regulated with gambogenic acid, while the expressions of PI3 K and Akt protein was insignificant. The results of RT-PCR indicated that the expressions of PI3 K and Akt protein were up-regulated by PTEN siRNA. Gambogenic acid can inhibit angiogenesis in lung cancer in vitro, and the mechanism of inhibiting angiogenesis may be related to the PI3 K/Akt signaling pathway.