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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 study the effect of endogenous nitric oxide (NO) on the chemosensitivity of tumor cells. Methods: The cultured MCF-7 cells were treated with IL-1β to detect the production of NO. The expression of inducible nitric oxide synthase (iNOS) protein was detected by Western blotting. The experimental group and the control group were established. MTT assay was used to detect the expression of N-methyl-L-arginine (L-NMMA) and L-arginine (L-Arg) on drug sensitivity to doxorubicin (ADM) and fluorouracil (5-FU). Results: There was a dose-dependent relationship between the production of endogenous NO and IL-1β. Western blot analysis showed that the cells expressed a large amount of iNOS protein under the induction of IL-1β. No difference was found in iNOS protein regardless of the presence or absence of L-Arg and L-NMMA. When the ADM concentration of 0.5 and 1μmol / L, the experimental group of cell survival rate decreased significantly, P <0.05. L-NMMA significantly increased the survival rate of the experimental group of cells, P <0.05; L-Arg addition, to some extent, increased the sensitivity of chemotherapy drugs, P <0.05. When L-Arg and L-NMMA were present together with IL-1β, there was no significant decrease in the survival rate of tumor cells (P <0.05). Conclusion: Endogenous NO produced by MCF-7 can enhance the chemosensitivity of tumor cells induced by IL-1β.