大黄素在体外诱导人肝癌细胞HepG2发生凋亡的初步研究

背景与目的:大黄素(3-甲基-1,6,8-三羟蒽醌)是大黄等多种中药的有效成分之一。研究表明大黄素对于乳腺癌细胞、肺癌细胞的生长具有抑制作用,但目前大黄素抗肿瘤的作用机理尚不明确。本研究拟讨论大黄素在体外对肝癌细胞HepG2的作用及其机理。方法:应用MTT、软琼脂克隆形成、DNAladder凝胶电泳及流式细胞术等方法,研究中药单体大黄素对肝癌细胞HepG2生长增殖的影响以及作用机理。结果:大黄素在较低浓度可抑制肿瘤细胞的生长,MTT实验测得的半数抑制浓度(IC50)为(36±2.6)μg/ml。在软琼脂实验中,大黄素可以浓度依赖的方式抑制细胞克隆的形成。经DNAladder及流式细胞仪检测发现,大黄素能诱导HepG2细胞凋亡,与阴性对照相比,随着药物浓度从10μg/ml增加到20μg/ml,AnnexinV染色细胞显著增多,由27.3%增至59.6%;当药物浓度增至40μg/ml时,培养液中几乎无活细胞,由碘化丙啶和AnnexinV双重标记的凋亡后期以继发性坏死细胞为主。结论:中药单体大黄素在体外能抑制肝癌细胞HepG2的生长增殖,并能诱导该细胞凋亡。

Apoptosis of human hepatoma HepG2 cells induced by emodin in vitro

BACKGROUND & OBJECTIVE: Emodin (3-methyl-1,6,8-trihydro- xyanthrax-quinone) is the main effective composition of some Chinese herbs. Previous studies showed that emodin could inhibit the proliferation of some kind of tumor cells, such as breast cancer and lung cancer, while the mechanism(s) by which emodin suppresses tumor growth remains unknown. The study was designed to investigate the inhibitory effects and mechanisms of emodin-induced cell death in human hepatoma cell HepG2. METHODS: MTT assay was used to evaluate the IC(50) of emodin on HepG2 cells. Through soft agar assay, the ability of cell proliferation when exposed to emodin at various dosages was detected. DNA fragmentation (ladder) and flow cytometry analysis were applied to investigate the effects and mechanisms of emodin on HepG2 cells. RESULTS: Emodin could inhibit the growth of HepG2 cells significantly with IC(50) of 36+/-2.6 microg/ml; and could inhibit the colony formation of the cells in soft agar. After treatment of emodin,extraction of cancer cells exhibited typical DNA fragmentation, and flow cytometry analysis showed apoptosis in a dosage- dependent manner. As the concentration of emodin raised from 10 microg/ml to 20 microg/ml,the ratio of apoptotic cells increased from 27.3% to 59.6%. Under the concentration of 40 microg/ml, there were almost no living cells detected. CONCLUSION: Emodin may inhibit the growth and proliferation of HepG2 cells through the way of apoptosis introduction.