Li Pei, Chen Che, Xi Ya-Ming, Zhang Hao, Li Ming, Deng Wei
Institute of Hematology, Department of Hematology, Lanzhou University First Clinical Hospital, Lanzhou 730000, Gansu Province, China.
Zhongguo Shi Yan Xue Ye Xue Za Zhi. 2011 Jun;19(3):638-42.
This study was purposed to investigate the growth inhibition and apoptosis-inducing effect of Clostridium difficile toxin A (TcdA) on the leukemia cell line K562. The proliferative activity of K562 cells exposed to Tcd A was tested by MTT assay, cell apoptosis was detected by flow cytometry; immunocytochemistry and colorimetric assay were employed to detect the protein expressions of BCL-2/BAX and the activity of Caspase-3, respectively. The results indicated that the proliferation of K562 cells was inhibited in a time-and dose-dependent manner after exposure to Tcd A for 24, 48 and 72 hours, the cells displayed the typical apoptotic, morphological changes, the expression of BCL-2 protein was down-regulated but the expression of BAX protein was signficantly increased, compared with control group (p < 0.05). In addition, caspase-3 was activated in a concentration-dependent manner. It is concluded that Tcd A inhibits cell growth of K562 by inducing apoptosis, and the up-regulation of BAX protein and activation of caspase-3 may play important roles in these processes.
本研究旨在探讨艰难梭菌毒素A（TcdA）对白血病细胞系K562的生长抑制和诱导凋亡作用。采用MTT法检测TcdA作用后K562细胞的增殖活性，流式细胞术检测细胞凋亡；分别采用免疫细胞化学法和比色法检测BCL-2/BAX蛋白表达及Caspase-3活性。结果显示，TcdA作用24、48和72小时后，K562细胞的增殖呈时间和剂量依赖性抑制，细胞呈现典型的凋亡形态学改变，与对照组相比，BCL-2蛋白表达下调，BAX蛋白表达显著增加（p<0.05）。此外，Caspase-3呈浓度依赖性激活。结论：TcdA通过诱导凋亡抑制K562细胞生长，BAX蛋白上调和Caspase-3激活可能在这些过程中起重要作用。
