Ononin Inhibits Tumor Bone Metastasis and Osteoclastogenesis By Targeting Mitogen-Activated Protein Kinase Pathway in Breast Cancer.

Breast cancer (BC) often spreads to bones, leading to bone metastasis (BM). Current targeted therapies have limited effectiveness in the treatment of this condition. Osteoclasts, which contribute to bone destruction, are crucial in supporting tumor cell growth in the bones. Breast cancer bone metastasis (BCBM) treatments have limited efficacy and can cause adverse effects. Ononin exhibits anticancer properties against various cancers. The study examined the impact of ononin on the BCBM and the signaling pathways involved. Our study utilized a variety of experimental techniques, including cell viability assays, colony formation assays, wound-healing assays, Transwell migration assays, Western blot analysis, and tartrate-resistant acid phosphatase (TRAP) staining. We examined the effects of ononin on osteoclastogenesis induced in MDA-MB-231 conditioned medium- and RANKL-treated RAW 264.7 cells. In a mouse model of BCBM, ononin reduced tumor-induced bone destruction. Ononin treatment effectively inhibited proliferation and colony formation and reduced the metastatic capabilities of MDA-MB-231 cells by suppressing cell adhesion, invasiveness, and motility and reversing epithelial-mesenchymal transition (EMT) markers. Ononin markedly suppressed osteoclast formation and osteolysis-associated factors in MDA-MB-231 cells, as well as blocked the activation of the mitogen-activated protein kinase (MAPK) pathway in RAW 264.7 cells. Ononin treatment down-regulated the phosphorylation of MAPK signaling pathways, as confirmed using MAPK agonists or inhibitors. Ononin treatment had no adverse effects on the organ function. Our findings suggest that ononin has therapeutic potential as a BCBM treatment by targeting the MAPK pathway.