铁过载对人乳腺癌细胞c-MYC蛋白表达的影响

Effect of iron overload on c-MYC protein expression in human breast cancer cell

目的研究铁过载催化的氧化应激对乳腺癌细胞中癌前因子c-MYC影响。方法分别以0、50和500μmol/L硫酸亚铁溶液培养人乳腺癌MCF-7细胞系24 h后,以细胞荧光染色法检测ROS活性,Western blot检测IRP1、IRP2、c-MYC、p-ERK1/2、GSK和PP2A蛋白的表达。加入NADPH氧化酶抑制剂二苯基碘(DPI)后检测ROS活性和c-MYC蛋白表达。结果随着铁剂量的增加,MCF-7细胞内ROS活性和IRP2蛋白表达均显著增加(P<0.05),IRP1无明显改变。铁过载还显著增加c-MYC蛋白表达,促进ERK1/2的磷酸化,降低GSK、PP2A蛋白表达(P<0.05)。加入DPI后,铁诱导的ROS活性及c-MYC蛋白表达被显著抑制(P<0.05)。结论铁过载可以通过诱导细胞内ROS活性的增强上调乳腺癌细胞c-MYC蛋白的表达。

Objective To investigate the effects of iron overloading induced oxidative stress on the expression of c-MYC protein in human breast cancer cells. Methods The human breast cancer MCF-7 cell line was treated by0,50 and 500 μmol / L ferrous sulfate respectively. After 24 hours,immunocytochemistry stain and Western blot methods were used to investigate the changes of reactive oxygen species and the expression of IRP1,IRP2,c-MYC,p-ERK,GSK,PP2 A protein. The changes of ROS activity and c-MYC protein were further examed by blocking NADPH oxidase pathway using Diphenyliodonium iodide（ DPI）. Results With the increase of ferrous sulfate,both ROS activity of and IRP2 protein expression of MCF-7 cell were increased significantly（ P 0. 05）,but IRP1 was not. Iron overload also increased c-MYC protein expression,and enhanced the levels of phosphorylation of ERK1 /2 and reduced the expressions of GSK and PP2 A proteins（ P 0. 05）. NADPH oxidase inhibitor（ DPI）could significantly inhibit the enhancement of ROS activity and the expression of c-MYC protein（ P 0. 05）.Conclusions Iron overload may enhance the expression of c-MYC protein by upregulation of ROS activity.