Dihydrotanshinone-I modulates Epithelial Mesenchymal Transition (EMT) Thereby Impairing Migration and Clonogenicity of Triple Negative Breast Cancer Cells

BACKGROUND: Salvia miltiorrhiza Bunge (Danshen), has been used for its therapeutic value in Traditional Chinese Medicine (TCM), for almost a thousand years. Dihydrotanshinone-I (DHTS) is a lipophilic compound isolated from the plant Salvia miltiorrhiza that has been shown to induce anti-proliferative and apoptotic effects on breast cancer cells. In the present study, we investigated the anti-migratory effect of DHTS on TNBC cell lines by studying the Epithelial Mesenchymal Transition (EMT) changes. METHODS: IC(50) values for DHTS in TNBC breast cancer cells were either discovered by literature search or by performing MTT assay. DHTS effect on EMT markers (viz. CD44, E-cadherin, Vimentin, N-cadherin, and active β-catenin) was studied using western blotting. Association between EMT and migration was further carried out in DHTS treated TNBC cells by wound healing assay. Cancer stemness and proliferation potential were further accessed using colony formation assay. RESULTS: MTT assay revealed IC(50) of MDA-MB-468 cells at 2 µM for 24 h. Subsequently, DHTS treatment in TNBC cell lines (MDA-MB-468 and MDA-MB-231) led to decrease in mesenchymal markers i.e. vimentin, N-cadherin and, active β-catenin. DHTS treated MDA-MB-468 cells showed a decrease in adhesion protein CD44 and an increase in epithelial protein E-cadherin. Additionally, a decrease in EMT potential was positively associated with the inhibition of migration and clonogenic potential in DHTS treated TNBC cells. CONCLUSION: In this study, we have demonstrated for the first time that DHTS has the potential to inhibit the migration and clonogenicity of highly aggressive TNBC cells by obstructing Epithelial to Mesenchymal Transition.