TNF-α诱导Molt-4细胞Bcl-2蛋白磷酸化的周期特异性

TNF-α Induces Apoptosis of Molt-4 Cells and Cell Cycle Specificity of Bcl-2 Phosphorylation

目的以肿瘤坏死因子-α诱导的Molt-4细胞凋亡为模式,观察Bcl-2蛋白磷酸化有无细胞周期特异性,探讨膜受体途径介导的细胞凋亡的周期特异性发生机制。方法TNF-α诱导Molt-4细胞凋亡,API法检测细胞凋亡的细胞周期特异性。流式细胞仪分选各个细胞周期时相的细胞群,蛋白免疫印迹检测Bcl-2蛋白的细胞周期特异性表达。结果TNF-α诱导Molt-4细胞凋亡主要发生在细胞周期的G1期。Bcl-2蛋白在TNF-α诱导后表达增加,G1期Molt-4细胞中bcl-2部分磷酸化,在时间上与凋亡发生的时间一致。结论加入TNF-α培养的Molt-4细胞Bcl-2蛋白磷酸化失活与细胞凋亡的细胞周期时相一致,具有细胞周期特异性。

Objective To observe the expression of Bcl 2 and its phosphorylation in Molt-4 cells induced by tumor necrosis factor-α （TNF-α）,and to investigate the possible mechanism of cell cycle specificity of apoptosis. Methods Exponentially growing Molt-4 cells were treated with TNF-α. Apoptosis was detected by DNA fragmentation assay. API Method was applied to illustrate the cell cycle specificity of apoptotic cells. Cells of sub-phases were sorted by FACSvantage flow cytometer and then submitted to immunoblot. Results Molt-4 cells which were treated with TNF-α went to apoptosis and showed a DNA ladder pattern. Most apoptosis happened in G1-phase of cell cycle. Bcl-2 expression increased for the Molt-4 cells treated with TNF-α. The phosphorylation state of Bcl-2 was only presented in G1-phase cells, in accordance with the specified time and cell cycle phase of apoptosis. Conclusion The phosphorylation of Bcl-2 in the Molt-4 cells treated with TNF-α happened with the same cell cycle specificity as cell apoptosis. The cell cycle specificity of Bcl-2 phosphoryaltion was one of the mechanisms of receptor-mediated apoptosis. The cell cycle machine can trigger the apoptosis program.