褪黑素、顺铂协同抑制人肝癌细胞SMMC-7721的机制研究

目的 研究褪黑素(melatonin，MLT)、顺铂(cisplatinumum，DDP)联用对人肝癌细胞SMMC-7721的抑制作用机制。方法用不同浓度的褪黑素、顺铂及二者联用处理人肝癌细胞株SMMC-7721，采用MTT法测定细胞抑制率；流式细胞仪分析细胞周期及凋亡；通过酶解可见光底物DEVD-pNp测定Caspase3的活性；Western blot分析p27^kipl蛋白表达。结果 ①褪黑素、顺铂单独应用和联合应用均能抑制SMMC-7721生长，且低浓度联合应用可达到甚至超过单用高浓度顺铂的抑制效果。②褪黑素无论与顺铂联用与否均能激活Caspase3，诱导细胞凋亡，而顺铂单独使用无此效应。③褪黑素与顺铂均可导致细胞周期阻滞，二者联用更明显。④褪黑素无论与顺铂联用与否均明显诱导p27^kipl的表达，而顺铂单独使用无此作用。结论 褪黑素能够通过诱导细胞凋亡和促进p27^kipl表达协同增强顺铂抑制肝癌细胞作用。

Inhibitory Effects and Mechanism of Melatonin in Combination with DDP on Human Hepatocarcinoma Cell Line SMMC-7721

Objective To study the inhibitory effects and mechanism of melatonin combined with cisplatinum on human hepatocarcinoma cell line SMMC-7721. Methods The inhibitory effects of melatonin and cisplatinum with various concentrations on the human hepatocarcinoma cell line SMMC-7721 in vitro were determined by using MTT method. The mechanism of the inhibition was observed by flow cytometry (FCM). The activity of Caspase3 and the expression level of p27 Kip1 were detected. Results Melatonin and cisplatinum used alone or combined use could inhibit the growth of SMMC-7721. The inhibitory effects of combined use of melatonin and cisplatinum at a low dose were similar to, even exceeded those of cisplatinum at a high dose. Melatonin both in the presence or absence of cisplatinum could activate Caspase 3, induce apoptosis, while cisplatinum used alone had no such effects. Both melatonin and cisplatinum could induce cell cycle arrest, especially in the combined use of them. Melatonin both in the presence or absence of cisplatinum could obviously induce the expression of p27 Kip1, while the cisplatinum used alone had no such effects. Conclusion Melatonin can enhance the inhibition of cisplatinum on the growth of human hepatocarcinoma cell SMMC-7721 by inducing apoptosis and cell cycle arrest and increasing the activity of Caspase3 and the expression level of p27 Kip1.