Curcumin Suppresses Doxorubicin-Induced Epithelial–Mesenchymal Transition via the Inhibition of TGF-β and PI3K/AKT Signaling Pathways in Triple-Negative Breast Cancer Cells

Triple-negative breast cancer (TNBC) is defined by a lack of expression of the estrogen receptor (ER), progesterone receptor (PR), and epidermal growth factor receptor 2 (HER 2). Therefore, targeted therapy agents may not be used, and therapy is largely limited to chemotherapy. Doxorubicin treatment consequently acquires undesired malignance characteristics [i.e., epithelial–mesenchymal transition (EMT) and multi-drug resistance]. Our results illustrated that doxorubicin triggered EMT and resulted in the acquisition of a mesenchymal phenotype in TNBC cells. Moreover, we found that transforming growth factor-β (TGF-β) and PI3K/AKT signaling pathways were acquired for doxorubicin-induced EMT. Interestingly, we found that curcumin suppressed doxorubicin-induced EMT. Curcumin reversed doxorubicin-induced morphological changes, inhibited doxorubicin-induced downregulation of E-cadherin expressions, and inhibited doxorubicin-induced upregulation of vimentin expression. We also found that curcumin inhibited doxo...