Inhibitory Effect Of Flavonoid Xanthomicrol On Triple-Negative Breast Tumor Via Regulation Of Cancer-Associated Micrornas

Breast cancer is the leading cause of cancer death in women worldwide. Due to the side effects of current chemo-reagents on healthy tissues, it is essential to search for alternative compounds with less toxicity and better efficacy. In the present study, we have investigated the anticancer effects of flavonoid xanthomicrol on the mice breast cancer model using MTT assay, cell cycle and Annexin/PI analysis, colony formation assay, H&E staining, immunohistochemistry, and miRNA analysis. Our results demonstrated that xanthomicrol decreased the cell viability and clonogenic capability, induced G1-arrest and apoptosis in the breast cancer cells in vitro, and caused a significant reduction in the volume and weight of mice tumors in vivo. In addition, xanthomicrol reduced the expression of TNF alpha, VEGF, MMP9, and Ki67, while upregulating the expression of apoptotic markers such as Bax, caspase3, and caspase9. Finally, the expression of miR21, miR27, and miR125, known as oncomirs, decreased significantly after xanthomicrol administration, while the expression of miR29 and miR34, functioning as tumor suppressors, increased significantly (p < .001). Our data demonstrated that xanthomicrol can induce apoptosis and suppress angiogenesis in breast cancer cells due to its inhibitory effect on oncomirs and its stimulatory effect on tumor suppressor miRNAs.