IκB-α蛋白降解对天花粉蛋白抗肿瘤作用的影响

Role of IκB-α Degradation on the Anti-tumor Effect Induced by Trichosanthin

[目的]检测天花粉蛋白(trichosanthin,TCS)对不同细胞株的生长抑制作用,并分析TCS处理后胞浆IκB-α蛋白水平的改变。[方法]人羊膜上皮细胞株FL、人宫颈癌上皮细胞株Hela、人滋养层绒毛膜癌细胞株JAR及大鼠肾上腺嗜铬细胞瘤细胞株PC12经一系列浓度TCS处理24h和48h后,采用MTT法检测细胞存活率。应用透射电子显微镜观察TCS处理后Hela和JAR细胞超微结构的改变。应用Westernblot法检测Hela、JAR和HepG2细胞经50μg/mlTCS处理不同时间点(30min、3h及12h)胞浆中IκB-α蛋白水平的改变。[结果]TCS能有效抑制Hela和JAR细胞生长,具有剂量和时间依赖性,且TCS对Hela细胞的生长抑制作用略强于JAR细胞;而TCS对FL和PC12细胞的生长抑制率较低。透射电镜观察显示,Hela和JAR均具有典型的凋亡细胞的特征。Westernblot检测显示,TCS处理后HepG2细胞IκB-α蛋白减少水平最明显,响应速度最快,JAR细胞次之,Hela细胞几乎无改变。[结论]TCS对细胞具有选择性杀伤的作用,具有较好的抗肿瘤应用前景;IκB-α蛋白降解导致的NFκB活化可能是影响肿瘤对TCS敏感性的机制之一。

[ Purpose ] To in vestigate the effect of trichosanthin（TCS） on cell growth inhibition in various cell lines,and the changes of cytoplasm IKB-ct level after treatment with TCS. [Meth- ods] Cell viability in FL,Hela,JAR and PC12 cell lines were determined by MTF method after treatment with various concentrations of TCS for 24h and 48h. Ultrastructural changes of Hela and JAR cells after TCS treatment were detected by transmission electron microscopy （TEM）. The levels of IKB-c in cytoplasmic extracts were detected by Western blot assay at different time intervals after Hela,JAR and HepG2 cells treated with 50g/ml TCS. [Results] TCS could significantly inhibit the cell growth of Hela and JAR cells with dose- and time-dependent manner,and the cell growth inhibition of Hela cell by TCS was slightly stronger than that of JAR cell, while TCS had very low toxicity to FL and PC12 cells. After TCS treatment,TEM showed that both Hela and JAR cells had typical cell apoptotic characteristics. Western blot showed that TCS could rapidly and obviously decrease the level of IKB-c protein in HepG2 cell,with the most and the fastest response,JAR cell was next,and almost no change in Hela cell. [Conclusionl TCS has effect of selective cell inhibition for various cell lines,with bright prospect for anti-tumor. IKB-ct protein degradation inducing NFKB activation might be one of the mechanisms of tumor sensitivity to TCS.