大肠杆菌感染时U937细胞凋亡与半胱氨酸蛋白酶-3及c-myc的关系

Relationship between the apoptosis of U937 cells and changes of caspases-3 and c-myc with E.coli infection

目的探讨大肠杆菌(Escherichia coli,E.coli)感染时人巨噬细胞系U937细胞凋亡与半胱氨酸蛋白酶-3(caspases-3)及c-myc的关系。方法当U937:E.coli分别为0,1∶20,1∶40及1∶80时用AnnexinV FITC/PI双染流式细胞仪检测细胞凋亡率,RT-PCR法检测caspases-3和c-myc的表达。结果当U937:E.coli分别为0,1∶20,1∶40及1∶80时,细胞凋亡率分别为(3.05%±0.88%)、(33.34%±4.27%)、(37.67%±5.20%)和(50.18%±4.32%)。caspases-3 mRNA和c-myc mRNA随着E.coli浓度增加而表达上调,与细胞凋亡程度基本一致。结论E.coli可诱导U937细胞凋亡,其机制可能与凋亡调控基因caspases-3和c-myc上调有关。说明多基因调控参与其中。

[Objective] To explore the relationship between the apoptosis of human monocytic U937 cells and the changes of caspases-3 and c-myc with E. coli infection. [Methods] U937 apoptosis was determined by AnnexinV-FITC assay. The expression of caspases-3 and c-myc was determined by RT-PCR. [Results] E. coli induced apop-tosis of U937 cells in a dose-dependent manner. Their apoptotic rates were （3.05%±0.88%）, （33.34%±4.27%）, （37.67%±5.2%） and （50.18%±4.32%） respectively. Along with the concentrations orE. coil, caspases-3 and c-mye expression up-regulated, eoincident with apoptosis rates of U937 cells. [Conclusion] E. coli induce U937 cells apoptosis in a dose-dependent manner. The mechanism could be related to the upregulation of apoptotie regulator gene c-mye and caspases-3. This suggested multiple-gene regulations participated in the U937 apoptosis induced by E. coli.