内源性NO对人乳腺癌细胞化疗敏感性的影响

目的 研究内源性一氧化氮(NO)对人乳腺癌细胞化疗敏感性的影响. 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(in-duceble nitric oxide synthase,iNOS)蛋白的表达.M1rr法检测MCF-7细胞在NOS抑制剂NG-甲基-L-精氨酸(NG-monomethyl-L-arginine,L-NMMA)和NO合成原料L-精氨酸(L-arginine,L-Arg)作用下对多柔比星(adriamycin,ADM)和5-氟尿嘧啶(5-fluorouracil,5-Fu)药物的敏感性. 结果内源性NO的产量与IL-1β剂量呈正相关.在IL-1β诱导作用下MCF-7细胞大量表达iNOS蛋白,并与L-Arg、L-NMMA存在与否无关.当ADM浓度为0.5 μmol/L和1 μmol/L时,实验组细胞的生存率明显下降(P<0.05).加入L-NMMA能显著提高实验组细胞的生存率(P<0.05);加入L-Arg能显著提高MCF-7细胞对化疗药物的敏感性(P<0.05).结论在细胞因子IL-1β诱导下MCF-7细胞产生的内源性NO增加,并使MCF-7细胞化学敏感性提高.

Effects of endogenous NO on sensitivity to chemotherapy in human breast cancer cell line

Objective To evaluate the effects of endogenous NO on the chemosensitivity of human breast cancer cell. Methods MCF-7 cells were cultured as monolayer, incubated with cytokine IL-1β. The pro-duction of NO was detected by NO assay. The expression of iNOS protein was measured by Western blotting. Establishing control group and experimental group, the chemosensitivity of MCF-7 cells incubated by L-NMMA and L-Arg to ADM and 5-Fu was studied by MTT assay. Results There was a positive correlation of dose-dependence between NO production and IL-1β concentration. MCF-7 cells expressed plenty of iNOS by induetion of IL-1β. There was no significant 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 experiment group was remarkablely decreased(P < 0.05) ; L-NMMA significantly increased survival rate of experiment group(P < O. 05) ; L-Arg decreased survival rate of experiment group(P < 0.05). Conclusion The induction of IL-113 in MCF-7 cells can increase the production of endogenous NO, which increases MCF-7 cells' sensitivity to chemotherapy.