小胶质细胞及其细胞因子对乳腺癌细胞的影响

目的:体外培养小胶质N9细胞并观察其条件培养液(conditioned medium,CM)对乳腺癌MCF-7细胞生存率的影响,以探讨小胶质细胞在脑转移癌中的作用机制.方法:混合培养N9细胞和MCF-7细胞,在倒置光学显微镜下观察细胞形态学的变化.采用脂多糖(lipopolysaccharide,LPS)、MCF-7细胞及其条件培养液MCF-7-CM刺激N9细胞获得N9-CM; ELISA法检测N9-CM中肿瘤坏死因子-α(tumor necrosis factor-α,TNF-α)、白细胞介素-17 (interleukin-17,IL-17)的表达,Griess体系检测一氧化氮(nitric oxide,NO)的生成量.将N9-CM按不同浓度(10％、25％、50％、75％和100％)作用于MCF-7细胞,MTT法检测Ng-CM对MCF-7细胞生存率的影响.结果:MCF-7细胞与N9细胞共培养,N9细胞由静止态变为激活态；LPS、MCF-7细胞及其上清液均可以诱导N9细胞产生TNF-α、IL-17和NO；N9-CM浓度达50％～100％时对MCF-7细胞生长有抑制作用,且作用强度呈时间-浓度相关性.结论:小胶质细胞可以被转移到CNS的乳腺癌细胞激活并发挥肿瘤抑制作用.其作用强度与小胶质细胞分泌NO及细胞因子TNF-α和IL-17的浓度和作用时间呈正相关性.

Effects of microglias and their cytokines on breast cancer cells

Objective:To investigate the effect of conditioned medium(CM) of microglia N9 cells cultured in vitro on the proliferation of breast cancer MCF-7 cells,and to explore the possible mechanism of microglias in the brain metastasis.Methods:The N9 cells and MCF-7 cells were co-cultured for 12 h,and then the morphological changes of the two cells were observed by an inverted optical microscope.The N9 cells were stimulated by lipopolysaccharide(LPS),co-culture with MCF-7 cells and the conditioned medium(MCF-7-CM) to produce N9-CM.The tumor necrosis factor-α(TNF-α) and interleukin-17(IL-17) in N9-CM were examined by ELISA,and the production of nitric oxide(NO) was detected by Griess system.MCF-7 cells were cultured with different concentrations(10%,25%,50%,75% and 100%) of N9-CM.The survival rate of MCF-7 cells was detected by MTT method.Results:N9 cells were activated by co-culture with MCF-7 cells;and the secretions of NO,IL-17 and TNF-α were induced by LPS,MCF-7 cells and MCF-7-CM.The proliferative rates of MCF-7 cells treated with N9-CM at concentrations of 50%-100% were decreased in a time-and concentration-dependent manner.Conclusion:Microglias can be activated by metastatic breast cancer cells in central nerve system and decrease the proliferation of the breast cancer cells.This effect is positively related to the levels of NO,IL-17 and TNF-α secreted by microglias and the treatment time of these cytokines.