姜黄素诱导人脑胶质瘤细胞U251分化的实验研究

目的探讨姜黄素对体外培养的人胶质瘤细胞U251的诱导分化作用及其机制。方法将人脑胶质瘤U251细胞分为对照组和药物组,对照组以含10%小牛血清的DMEM培养基常规培养,药物组用16μmol/L姜黄素（本实验先前的研究结果显示,姜黄素作用于U251细胞48h的半数抑制浓度为16μmol/L）处理。倒置显微镜观察细胞形态学变化;流式细胞仪检测细胞周期变化;免疫细胞化学法检测波形蛋白（vimentin）表达变化;免疫印迹（Westernblot）法检测细胞外调节蛋白激酶（ERK）、磷酸化细胞外调节蛋白激酶（pERK）和胶质纤维酸性蛋白（GFAP）表达变化。结果姜黄素作用96h后,与对照组相比,U251细胞突起明显增多变细长。姜黄素培养48h,S期细胞由28.53%明显降低至20.35%（P=0.015）;vimentin强阳性细胞百分率由90%明显降低至50%（P=0.009）;GFAP蛋白与内参β-actin表达量的比值由0.22明显升高至0.50（P=0.01）。Westernblot法显示,姜黄素分别作用于U251细胞48和96h,ERK蛋白水平无明显改变,pERK/ERK分别为0.35和0.22,较对照组明显减少（P=0.03和0.007）。结论姜黄素对体外培养的胶质瘤U251细胞有显著的诱导分化作用,其机制可能与抑制异常激活的ERK信号通路有关。

EFFECT OF CURCUMIN ON THE DIFFERENTIATION OF HUMAN GLIOMA CELL U251

Objective To investigate the effect of curcumin on the differentiation of human glioma cell U25J and the mechanism. Methods We studied on the two groups, the normal controls and the treatment groups with 16μmol/L curcumin in human glioma cell U251. The cellular differentiation was determined by inverted microscopy. The cell cycle distribution was determined by flow cytometry. The expression of vimentin was measured by immunocytochemistry. The levels of GFAP, total and phosphorylated ERK were assessed by Western blot analysis. Results We treated U251 cells with cureumin for 96h and saw cells with more processes which were longer and slimmer. When the curcumin therapy time was 48h , the percentage of cells in s phase was lowered significantly from 28.53% to 20. 35% （P=0. 015） . The percentage of vimentin strong positive cells decreased from 90% to 50% （P=0. 009） . The ratio of GFAP to β-actin increased from 0. 22 to 0.50 （P=0.01） . When the time of therapy was 48 and 96h, the ratio of pERK to ERK was 0. 35 and 0.22 （P=0. 03 and 0. 007） . Conclusion Curcumin may induce differentiation of human glioma U251 cells. This effect may result from the blocking of the ERK pathway.