低浓度MNNG诱发非DNA损伤依赖的细胞信号通路  

Activation of nucleus-independent signals triggered by N-methyl-N'-nitro-N-nitrosoguanidine

作　　者：王政[1] 王谷亮[1] 杨军[1] 高志华[1] 余应年[1] 

机构地区：[1]浙江大学医学院病理生理教研室,浙江杭州310031

出　　处：《浙江大学学报（医学版）》2003年第5期385-389,共5页Journal of Zhejiang University(Medical Sciences)

基　　金：国家重点基础研究发展规划 (973)资助(2 0 0 2 CB5 12 90 1);国家自然科学基金重点资助 (39830 2 10 )

摘　　要：目的 :研究基因组 DNA损伤与细胞信号通路激活的关系以及低浓度 N-甲基 - N’-硝基 - N-亚硝基胍(MNNG)对细胞膜表面受体的影响。方法 :采用 ELISA法来检测蛋白激酶 A(PKA)的活性 ,不连续梯度密度离心法完成细胞脱核 ,以及免疫荧光法和激光共聚焦显微镜观察细胞表面受体聚集情况。结果 :0 .2 μmol/ L MNNG能在脱核细胞中引起 PKA活性升高 2 .3倍 ,并可在 5 min内引起 vero细胞表面生长因子受体和肿瘤坏死因子 α受体的聚集 ;在脱核细胞中 ,表面受体聚集现象与在完整细胞中一样。结论 :低浓度 MNNG对 PKA的激活和诱导细胞表面受体聚集均不依赖于基因组 DNA的损伤 ,表明细胞信号转导通路的起源可能位于细胞膜或者细胞质中。Objective: To study the effect of MNNG on inducement of non-targeted mutation and activation of several cellular signal transduction pathways, and to determine whether the activation of these signaling pathways was dependent on the DNA-damage. Methods: Vero cells were enucleated by discontinuous density centrifugation. The PKA activities were measured by enzyme-linked immunosorbent assay. The status of cell membrane receptors was studied with immunofluorescent staining and confocal microscopy. Results: In enucleated cytoplasts, MNNG-treatment increased PKA activity for about 2.3-fold in accordance with the 2.7-fold up-regulation of PKA activity in whole vero cells exposed to MNNG. The clustering of cell surface receptors of epidermal growth factor and tumor necrosis factor α was also observed in cells exposed to MNNG; this phenomenon was also found in enucleated cells. Conclusion: The results indicate that the initiation of signal cascades induced by low concentration of MNNG might be associated with its interaction with cell surface receptors and/or direct activation of related signal proteins but not its DNA damage.

关 键 词：N-甲基-N'-硝基-N-亚硝基胍 Vero细胞 DNA损伤 信号传递 蛋白激酶A 生长调节素受体 肿瘤坏死因子受体 

分 类 号：R363[医药卫生—病理学]