Objective: To investigate quinalizarin-induced apoptosis in gastric cancer cells in vitro and explore the molecular mechanisms.
Methods: MTT assay was used to determine the cytotoxic effects of quinalizarin on human gastric cancer AGS, MKN-28 and MKN-45 cells. Annexin V-FITC/PI staining and flow cytometry were used to assess quinalizarin-induced apoptosis in AGS cells and its effect on intracellular ROS levels; the expression levels of apoptotic proteins in the cells were determined with Western blotting.
Results: Quinalizarin dose-dependently reduced the cell viabilities of the 3 gastric cancer cells (P<0.05). The IC50 values of quinalizarin in AGS, MKN-28 and MKN-45 cells were 7.07 µmol/L, 22.55 µmol/L and 14.18 µmol/L, respectively. Quinalizarin time-dependently induced apoptosis of AGS cells and potentiated the generation of intracellular reactive oxygen species (ROS) levels. Pretreatment with NAC, a scavenger of ROS, inhibited quinalizarin-induced apoptosis (P<0.001). Western blotting results showed that quinalizarin also up-regulated the expression levels of the apoptotic proteins including p-p38, p-JNK, Bad, cleaved caspase-3, and cleaved PARP-1 (P<0.05), and down-regulated the expression of the anti-apoptotic proteins p-Akt, p-ERK, and Bcl-2 (P<0.05).
Conclusion: Quinalizarin inhibits the proliferation and induces apoptosis in gastric cancer cells in vitro through regulating intracellular ROS levels via the MAPK and Akt signaling pathways.
目的: 探讨醌茜素对人胃癌细胞的凋亡作用及其分子机制。
方法: MTT法检测醌茜素对3种人胃癌AGS、MKN-28及MKN-45细胞的杀伤作用；Annexin V-FITC/PI双染法、流式细胞术检测醌茜素诱导AGS细胞凋亡能力及细胞内活性氧簇（ROS）水平；蛋白质免疫印迹法检测细胞凋亡相关蛋白的表达量变化。
结果: 醌茜素对3种胃癌细胞均具有明显的杀伤作用, 且呈浓度依赖性（P < 0.05）。经计算其IC50值分别为7.07 μmol/L、22.55 μmol/L及14.18 μmol/L。醌茜素能诱导AGS细胞发生凋亡, 且呈浓度依赖性（P < 0.001）, 并能够促进细胞内活性氧水平升高（P < 0.001）。当预处理ROS清除剂NAC后, 能够明显抑制醌茜素诱导的细胞凋亡（P < 0.001）。Western blotting结果显示促凋亡蛋白p-p38、p-JNK、Bad、cleaved-caspase-3及cleaved-PARP-1表达量增加（P < 0.05）, 抗凋亡蛋白p-Akt、p-ERK及Bcl-2蛋白表达量减小（P < 0.05）。
结论: 醌茜素通过上调细胞内ROS水平, 调控MAPK及Akt信号途径, 进而诱导人胃癌AGS细胞发生凋亡