关键词: 乳腺肿瘤, 薯蓣皂苷, 三苯氧胺, 细胞凋亡, 自噬

Abstract: Background　Tamoxifen is a main drug used for endocrine treatment of breast cancer.It is difficult to treat breast cancer resistant to tamoxifen，and new treatments are needed urgently.Diosgenin（Dio） can inhibit the growth of cancer to some extent.Studying the effect of Dio on the growth of tamoxifen-resistant（TAM-R） breast cancer cells can provide a reference for clinical treatment.Objective　To study the effects of Dio on the growth of TAM-R breast cancer cells.Methods　From January 2017 to June 2018，TAM-R breast cancer cells were cultured.Corresponding experiments were carried out on cell growth and apoptosis，autophagy and apoptotic markers，and anti-cancer proteins.The details are as follows：automated cell counters were used to count the number of TAM-R breast cancer cells in six groups（control，Dio 0.625 μg/ml，Dio 0.800 μg/ml，Dio 1.000 μg/ml，Dio 1.250 μg/ml and Dio 2.500 μg/ml） after being treated by different doses of Dio for five days，and to measure the apoptosis of TAM-R breast cancer cells in 6 groups（control，TAM 10-7 mol/L，Dio 1 μg/ml，Dio 2 μg/ml，TAM 10-7 mol/L+Dio 1 μg/ml，and TAM 10-7 mol/L+Dio 2 μg/ml） treated with different doses of TAM and Dio for three days.Immunoblotting was used to detect the effects of different doses of Dio on TAM-R autophagy markers LC3 and Beclin-1，and apoptotic markers Bax，Bim，pAMPK and p53 proteins in four groups（control，Dio 0.80 μg/ml，Dio 1.25 μg/ml，and Dio 2.50 μg/ml）．Autophagy of TAM-R breast cancer cells treated with Dio and its inhibitors and inducers in six groups（control，Rapamycin 20 nmol/L，Chloroquine 10 μmol/L，TAM 10-7 mol/L，Dio 1 μg/ml，and TAM 10-7 mol/L+Dio 1 μg/ml） was observed by autophagic fluorescence microscopy.Results　The number of TAM-R breast cancer cells differed significantly across different groups （P<0.05）．To be specific，the control group had much less TAM-R breast cancer cells than Dio groups（P<0.05）．The number of apoptotic TAM-R breast cancer cells varied obviously across different groups（P<0.05）．Specifically，the control group showed much less apoptotic TAM-R breast cancer cells than other five groups（P<0.05）．Moreover，TAM 10-7 mol/L+Dio 2 μg/ml group showed significantly less TAM-R breast cancer cells than Dio 2 μg/ml group（P<0.05）．The expressions of LC3，Beclin-1，Bax，Bim，pAMPK and p53 varied significantly across the groups （P<0.05）．Fluorescence microscopy showed that autophagic activity level of TAM 10-7 mol/L + Dio 1 μg/ml group was higher than that of Dio 1 μg/ml group and TAM 10-7 mol/L group.Conclusion　Dio could inhibit the growth of TAM-R breast cancer cells，and strengthen the growth inhibition and apoptosis enhancement effects of TAM on such cells.Moreover，both autophagy and apoptotic marker proteins were also influenced.

Key words: Breast neoplasms, Dioscin, Tamoxifen, Apoptosis, Autophagy