Objective: To investigate the effect of aloin on apoptosis of human gastric cancer cells and explore the molecular mechanism.
Methods: Gastric cancer MKN-28 and HGC-27 cells were cultured routinely in 1640 medium supplemented with 10% fetal bovine serum and 10% non-essential amino acids (for HGC-27 cells) and treated with different concentrations of aloin for different durations. The cell viability, cell nuclear morphology, and apoptotic rate of the cells were detected using CCK-8 assay, DAPI staining and AnnexinV-FITC/PI, respectively; Western blotting was used to detect the expression levels of PARP, procaspase 3 and the phosphorylation of p38, ERK and JNK. The cells were treated with specific inhibitors of p38, ERK and JNK, and the inhibitory effects on these pathways were detected with Western blotting; DAPI staining was used to detect the effects of inhibitors on apoptosis of gastric cancer cells.
Results: Aloin dose-dependently inhibited the viability and induced apoptosis of HGC-27 and MKN-28 cells. Alion treatment obvious enhanced the phosphorylation of p38 and JNK but decreased ERK phosphorylation in the cells. Blocking ERK activation with the ERK inhibitor obviously enhanced aloin-induced cell apoptosis, where inhibiting p38 and JNK activation partly reversed alion-induced apoptosis in the cells.
Conclusions: Aloin induces apoptosis of human gastric cancer cells in vitro by activating p38 and JNK signaling pathways and inhibiting ERK signaling pathway.
目的: 探讨芦荟苷对人胃癌MKN-28和HGC-27细胞凋亡的诱导作用及可能的分子机制。
方法: 胃癌MKN-28和HGC-27细胞用含10%胎牛血清和NEAA（HGC-27细胞）的1640完全培养基常规培养，不同浓度的芦荟苷处理胃癌MKN-28和HGC-27细胞特定的时间，CCK-8实验检测芦荟苷对MKN-28和HGC-27细胞活力的影响；DAPI染色观察凋亡细胞核的形态改变；AnnexinV-FITC/PI双染法检测细胞凋亡率；Western blotting检测凋亡相关蛋白PARP和procaspase-3的表达及MAPKs信号通路p38，ERK及JNK的磷酸化水平；p38，ERK及JNK的特异性抑制剂处理细胞，WB检测抑制剂的对p38，ERK及JNK激活的抑制效果，DAPI染色观察抑制剂对胃癌细胞凋亡的影响。
结果: 芦荟苷浓度依赖性地抑制胃癌MKN-28和HGC-27细胞的活力，诱导胃癌细胞凋亡；芦荟苷处理胃癌细胞后，胞内JNK和p38的磷酸化水平明显增加，而ERK的磷酸化水平下降。特异性抑制剂阻断ERK活化，能够增强芦荟苷诱导的细胞凋亡，阻断p38和JNK的激活，能够部分逆转芦荟苷诱发的胃癌细胞凋亡。
结论: 芦荟苷通过激活JNK和p38信号途径，抑制ERK信号途径诱导胃癌细胞凋亡。
Keywords: HGC-27 cells; MAPKs signaling pathway; MKN-28 cells; aloin; apoptosis.