Abstract:

Objective： To discuss the effect of Huaier aqueous extract （HAE） on the proliferation， migration， cell cycle，and apoptosis of tamoxifen （TAM） resistant breast cancer LCC2 cells， and to clarify its mechanism. Methods The cells were divided into control group （given DMEM basal medium） and TAM group （given 2 μmol·L^－1 TAM）， TAM+HAE group （given 2 μmol·L^－1 TAM+4 g·L^－1 HAE） and 0， 2， 4， 8， and 16 g·L^－1 HAE groups. MTT method was used to detect the survival rates and the proliferation rates of the cells in various groups； cell scratch test was used to detect the migration rates of the cells in various groups；flow cytometry was used to detect the percentages of the cells at different cell cycles and apoptotic rates of the cells in various groups；Transwell chamber test was used to detect the migration number of the cells in various groups； Western blotting method was used to detect the expression levels of estrogen receptor α （ER α） in each group，amplified in breast cancer 1（AIB1），and survivin proteins in the cells in various groups. Results The MTT assay showed that after treated for 24 h， compared with 0 g·L^－1 HAE group， the survival rates of the HAE cells in 4，8，and 16 g·L^－1 HAE groups were significantly decreased（P<0.01）. At 48 h after treatment， compared with 0 g·L^－1 HAE group， the survival rates of the cells in 2，4，8， and 16 g·L^－1 HAE groups were significantly decreased （P<0.01）；compared with 4 g·L^－1 HAE group，the survival rate of the cells in 8 g·L^－1 HAE groups was decreased（P<0.05）；compared with 24 h after treatment， the surival rates of the cells in different concentrations of HAE groups were significantly decreased （P<0.01） after treated for 48 h. At 48 treatment，compared with TAM and 4 g·L^－1 HAE group，the proliferation rate of the cells in TAM+HAE group was significantly decreased（P<0.01）.The cell scratch test results showed that the cell migration rate of the cells in 4 g·L^－1 HAE group was lower than that in 0 g·L^－1 HAE group after treated for 48 h （P<0.05）. The flow cytometry results showed that after treated for 48 h， compared with 0 g·L^－1 HAE group， the percentage of the cells at S phase and the apoptotic rate of the cells in 4 g·L^－1HAE group were significantly increased （P<0.05 or P<0.01）. The Transwell chamber experiment results showed that after treated for 48 h， compared with TAM group and 4 g·L^－1 HAE group， the migration number of the cells in TAM+HAE group was significantly decreased （P<0.01）. The Western blotting results showed that compared with MCF-7 cells，the expression levels of ERα，AIB1， and survivin proteins in the LCC2 cells were increased （P<0.05 or P<0.01）；at 48 h after treatment， compared with 0 g·L^－1 HAE group，the expression levels of ERα，AIB1， and survivin proteins in the LCC2 cells in 2，4，8， and 16 g·L^－1 HAE groups were significantly decreased （P<0.01）. Conclusion HAE can inhibit the proliferation and migration， arrest the cell cycle at S phase， and promote the apoptosis of the LCC2 cells，and it can also restore the sensitivity of the LCC2 cells to TAM， and its mechanism may be related to down-regulation of the expression levels of ER α， AIB1，and survivin proteins in the LCC2 cells.

Key words: Breast cancer, Huaier aqueous extract, Tamoxifen, Cell proliferation, Drug resistance