莪术醇诱导人肝癌HepG2细胞衰老及其机制研究

为进一步探讨莪术醇的诱导细胞衰老的机制,该研究采用荧光定量PCR技术对莪术醇处理后细胞中81个细胞衰老相关基因差异表达谱进行分析,结果发现TP53及其下游基因p16Ink4a、p21Waf1/Cip1和p27Kip1等的表达水平显著升高,伴随ABL1、ALDH1A3、CHEK2、HRAS、PTEN等多个衰老信号通路启动与效应关联基因的转录显著增强,而CyclinA2、IGFBP3、SIRT1以及TERT等细胞周期进程与衰老信号通路的负性调控基因的表达水平则显著降低。Western印迹检测结果显示,p53及其下游周期素依赖性蛋白激酶抑制物(CKI)分子p21WAF1和p16INK4水平升高,CyclinA2水平降低,与PCR结果一致,并伴野生型p53-诱导的蛋白磷酸酶1(Wip1)水平显著增高,提示莪术醇可能通过激活p53信号通路诱导HepG2细胞衰老。该研究进一步发现莪术醇能够诱导HepG2细胞发生衰老表型改变,伴G0/G1期周期阻滞。

Human hepatocarcinoma HepG2 cell senescence induced by curcumol and underlying mechanisms

In order to further study the antitumor mechanism of curcumol and its potential clinical application, a SYBR Green real-time polymerase chain reaction(RT-PCR)method was used to analyze the differential expression profiles of 81 human senescence-related genes in human hepatocarcinoma HepG2 cells treated with curcumol. The results showed that the expression of TP53 and its downstream genes p16Ink4a, p21Waf1 / Cip1 and p27Kip1 were significantly up-regulated, accompanied by transactivation of other senescence signaling pathway related genes or senescence response genes such as ABL1, ALDH1A3, CHEK2, HRAS, PTEN, etc., while the expression of Cyclin A2, IGFBP3, SIRT1 and TERT, the genes which negatively regulated cell cycle progression and senescence signaling, were significantly down-regulated. Western blotting verified that protein levels of p53 and its downstream CKIs, p21WAF1 and p16INK4 increased while Cyclin A2 decreased, consistent with the findings in PCR results. The level of wild-type p53-induced protein phosphatase 1(Wip1)was also found significantly increased, suggesting that the induction of senescence in HepG2 cells by curcumol might be through activation of p53 signaling pathway. The present study further demonstrates that curcumol is capable of inducing cellular senescent phenotype in HepG2, accompanying with cell cycle G0 / G1 phase arrest.