Different anticancer effects of Saxifragifolin A on estrogen receptor-positive and estrogen receptor-negative breast cancer cells.

Background: Breast cancer is the leading cause of cancer-related death among women worldwide. For treating breast cancer, numerous natural products have been considered as chemotherapeutic drugs.

Objective: The present study aims to investigate the apoptotic effect of Saxifragifolin A (Saxi A) isolated from Androsace umbellata in two different human breast cancer cells which are ER-positive MCF-7 cells and ER-negative MDA-MB-231 cells, and examine the molecular basis for its anticancer actions.

Methods: The inhibitory effects of Saxi A on cell survival were examined in MCF-7 cells and MDA-MB-231 cells in vitro. Methods: MTT assays, Annexin V/PI staining analysis, ROS production assay, Hoechst33342 staining and Western blot analysis were performed.

Results: Our results showed that MDA-MB-231 cells were more sensitive to Saxi A-induced apoptosis than MCF-7 cells. Saxi A induced apoptosis in MDA-MB-231 cells through ROS-mediated and caspase-dependent pathways, whereas treatment with Saxi A induced apoptosis in MCF-7 cells in a caspase-independent manner. In spite of Saxi A-induced activation of MAPKs in both breast cancer cell lines, only p38 MAPK and JNK mediated Saxi A-induced apoptosis. In addition, cell survival of shERα-transfected MCF-7 cells was decreased, while MDA-MB-231 cells that overexpress ERα remained viable.

Conclusions: Saxi A inhibits cell survival in MCF-7 cells and MDA-MB-231 cells through different regulatory pathway, and ERα status appears to be important for regulating Saxi A-induced apoptosis in breast cancer cells. Thus, Saxi A may have a potential therapeutic use for treating breast cancer.