Objective: We aim to investigate the anticancer effects and mechanisms of
icaritin against breast cancer.
Materials and Methods: Both estrogen receptor (ER) positive breast cancer cells MCF-
7 and ER-negative MDA-MB-231 cells were employed. We examined the effects of
icaritin on the proliferation and migration by wound healing assay and transwell assay.
Cell apoptosis and cell cycle of MCF-7 and MDA-MB-231 cells were analyzed using
Flow cytometry. Cell autophagy of MCF-7 and MDA-MB-231 cells was assessed by
western blotting, acridine orange staining and confocal microscopy. We also detected
the expression of apoptosis-related genes by western blotting. In addition, an autophagy
inhibitor was used to investigate whether cytoprotective autophagy was induced.
Meanwhile, an ER inhibitor was utilized to explore whether ER was involved in
Results: Icaritin inhibited the proliferation and migration, and induced cell cycle arrest of
both MDA-MB-231 and MCF-7 cells. Icaritin significantly induced apoptosis of MDA-MB-
231 cells by activating caspase-3. And icaritin stimulated autophagy in MCF-7 cells, as
evidenced by increased LC3II/LC3I, enhanced p62 degradation, the accumulation of
endogenous LC3 puncta formation, and the increased autophagy flux. Icaritin induced
autophagy through upregulating the phosphorylation of AMPK and ULK1. Chloroquine,
an autophagy inhibitor, increased icaritin-induced apoptosis and proliferation inhibition of
MCF-7 cells. Meanwhile, tamoxifen, an ER inhibitor, reversed icaritin-induced autophagy
and proliferation inhibition of MCF-7 cells.
Conclusion: Our study demonstrated that the antitumor effects of icaritin against breast
cancer are related to ER, which suggested that the status of ER should be considered in
the clinical application of icaritin.