自噬通过p38/c-Jun信号通路促进乳腺癌细胞对他莫昔芬耐药的研究

Autophagy facilitates breast cancer cells to resist tamoxifen by p38/c-Jun pathway

目的 探讨自噬在乳腺癌细胞中对他莫昔芬耐药的影响。方法 免疫荧光法计数MCF-7及MCF-7/TAMR中含有自噬体的细胞比例及平均每个细胞中自噬体的个数;蛋白印迹法检测MCF-7和MCF-7/TAMR中p38、c-Jun和LC3表达的差异;逐步法检测当LC3的表达改变时,产生耐药细胞株时间的差异。结果 与MCF-7比较,MCF-7/TAMR中含有自噬体的细胞比例及平均每个细胞中自噬体的个数均明显增多;MCF-7/TAMR中LC3蛋白的表达水平明显增高;在诱导TAM耐药过程中LC3的表达水平与耐药细胞株的产生时间呈负相关。在MCF-7/TAMR中磷酸化的p38和c-Jun表达明显增加。结论 自噬促进乳腺癌细胞对他莫昔芬耐药,通过降低自噬相关蛋白的表达活性能够抑制乳腺癌耐药细胞的产生,这可能成为难治性乳腺癌治疗的新途径。

Objective To investigate the effects of autophagy on breast cancer cells to tamoxifen resistance.Methods Immunofluorescence was used to count the proportion of the cells with autophagy in MCF-7 and MCF-7/TAMR,as well as,the average of autophagosome in each cells.Western blotting was used to detect the different expressions of p38,c-jun and LC3 in MCF-7 and MCF-7/TAMR.Stepwise selection was used to detect the duration of resistance to different doses of tamoxifen when upregulating or downregulating of LC3.Western blot was facilitated to investigate changes of activity of p38/c-jun.Rusults Compared with MCF-7,the proportion of the cells with autophagosome in MCF-7/TAMR was markedly increased,the same as the average of autophagosome in each cells.Compared with MCF-7,LC3,especially LC3IIprotein expressive levels in MCF-7 / TAMR was significantly increased.The expressive level of LC3 during the induction process of TAM resistance was negative correlated with resistant cell lines.The expressions of phosphorylated p38 and c-Jun in MCF-7/TAMR were significantly increased.Conclusion Autophagy promotes breast cancer cells to resistant to tamoxifen,due to downregulation of the expression of autophagy related proteins which may inhibit the generation of resistant breast cancer cells.This may be a viable treatment strategy for refractory breast cancer.