人乳腺癌细胞过量产生NO对ADM和5-FU敏感性的调节作用

Production of NO its and regulation of sensitivity to ADM and 5-FU in human breast cancer cell line

目的:研究内源性一氧化氮(NO)对于调节肿瘤细胞对化疗药物敏感性的影响。方法:应用IL-1β处理培养的MCF-7细胞检测NO的产生情况,并用蛋白质印迹法检测诱导型一氧化氮合酶(iNOS)蛋白的表达。设立实验组和对照组,采用MTT法检测MCF-7细胞在一氧化氮合酶(NOS)抑制剂NG-甲基-L-精氨酸(L-NMMA)和NO合成原料L-精氨酸(L-Arg)作用下,对多柔比星(ADM)和氟尿嘧啶(5-FU)的药物敏感性。结果:内源性NO的产生量与IL-1β间存在着剂量依赖关系。蛋白质印迹法分析结果显示,在IL-1β诱导作用下,细胞大量表达iNOS蛋白。同时无论L-Arg和L-NMMA存在与否,iNOS蛋白都无差异。当ADM浓度为0.5和1μmol/L时,实验组细胞生存率有较明显的下降,P<0.05。L-NMMA的加入显著提高了实验组细胞的生存率,P<0.05;L-Arg的加入,在一定程度上提高了化疗药的敏感性,P<0.05。当L-Arg和L-NMMA与IL-1β同时存在,肿瘤细胞的生存率不会有明显下降,P<0.05。结论:在细胞因子IL-1β诱导下,MCF-7产生的内源性NO能提高肿瘤细胞的化学敏感性。

OBJECTIVE：To evaluate the effects of endogenous NO on the chemosensitivity of human breast cancer cell MCF-7. METHODS：MCF-7 cells were cultured as monolayer,and incubated with cytokine IL-1β. The production of NO was detected by the NO assay. The expression of iNOS protein was measured by Western Blot. A control group and experimental group were established,the chemosensitivity of MCF-7 cells incubated by L-NMMA and L-Arg to ADM and 5-FU was studied by the MTT assay. RESULTS：There was a relation of dose-dependence between NO production and IL-1β concentration. The Western blot analysis showed that MCF-7 cells expressed plenty of iNOS by induction of IL-1β. There was no difference on iNOS whether L-NMMA and L-Arg existed or not. Incubating MCF-7 cells with 0.5 μmol/L or 1 μmol/L ADM,the survival rate of the experiment group significantly decreased （P0.05）; L-NMMA significantly increased the survival rate of the experiment group （P0.05）; L-Arg decreased the survival rate of the experiment group （P0.05）. However,the treatment of MCF-7 cells with L-NMMA and L-Arg simultaneously,the survival rate of the experiment group did not significantly decrease （P0.05）. CONCLUSION：Endogenous NO produced by MCF-7 cells can raise the chemosensitivity of MCF-7 cells with induction of IL-1β.