Autophagy facilitates breast cancer cells to resist tamoxifen by p38/c-Jun pathway / 实用肿瘤学杂志

ABSTRACT

Objective To investigate the effects of autophagy on breast cancer cells to tamoxifen resist-ance.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 LC 3.West-ern blot was facilitated to investigate changes of activity of p 38/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 p 38 and c-Jun in MCF-7/TAMR were significantly increased .Conclusion Autophagy promotes breast cancer cells to resistant to tamox-ifen,due to downregulation of the expression of autophagy related proteins which may inhibit the generation of re -sistant breast cancer cells .This may be a viable treatment strategy for refractory breast cancer .