Annexin A1 is responsible for ursolic acid mediated anticancer effects on breast cancer stem cells by wnt/β-catenin pathway

Abstract Background Ursolic acid (UA), a plant extract from traditional Chinese medicines as well as edible vegetables, exhibits a potent anticancer activity in various tumor cells. Annexin A1(AnxA1) is dysregulated and play a pivotal role in various tumor. However, the function of AnxA1 in breast cancer(BC) remains unclear. Methods Western blot, real-time quantitative polymerase chain reaction(qRT- PCR), transwell, wound healing and immunofluorescence were used to study the biological features of AnxA1 in breast cancer. The stemness of cancer cells was assessed by sphere formation assay. CCK-8 and flow cytometry assay were used to detect the effects of ursolic acid on the growth, proliferation and apoptosis of breast cancer cells in vitro. A nude mice xenograft model was employed in vivo. The potential mechanism by which Ursolic acid regulates the biological behaviors of breast cancer stem cells through AnxA1 via the wnt/β-catenin signaling pathway was tested by western blot, qRT- PCR and immunohistochemistry. Results AnxA1 was highly expressed in MDA-MB-231 cell line compared with MCF-7 cell line, Down-regulation of AnxA1 could reduce the mammosphere formation, inhibit EMT, decrease the ability of migration and invasion in MCF-7 and MDA-MB-231 cells. Ursolic acid can reduce the expression of AnxA1 and inhibit proliferation of breast cancer cells, stemness, EMT, migration and invasion, promote cell apoptosis of breast cancer cell. This studies suggest that the anticancer effects of AnxA1 knockdown and UA treatment may be realized by affecting the EMT process and the wnt/β-catenin signaling pathway. Conclusions This research suggest that AnxA1 knockdown enhanced the sensitivity of breast cancer cells to UA, the combination of UA treatment and AnxA1 knockdown possesses multiple anti-tumor activities against breast cancer, as it, in particular, inhibited the cancer stem cell and attenuated EMT. Therefore, it is emerging as a promising therapeutic strategy to inhibit breast cancer.