Oxymatrine reverses epithelial-mesenchymal transition in breast cancer cells by depressing αⅤβ3 integrin/FAK/PI3K/Akt signaling activation.

Oxymatrine, an alkaloid extracted from the Chinese herb Sophora flavescens Aiton, possesses anti-inflammatory, anti-immune, anti-hepatic fibrosis, and anti-cancer properties. However, the effects of oxymatrine on epithelial-mesenchymal transition (EMT) of breast cancer cells are still unclear.

The present study was performed to investigate whether oxymatrine reverses EMT in breast cancer cells and to explore the underlying molecular mechanisms.

MTT assay was performed to evaluate cell viability. Wound-healing assay and transwell chamber assay were used to assess cell migration and invasion, respectively. Immunofluorescence and Western blot were used to study the expression of EMT-related molecules and α_Ⅴβ₃ integrin/focal adhesion kinase (FAK)/phosphoinositide 3-kinase (PI3K)/protein kinase B (Akt) signaling transduction. Fibronectin, a physiologic ligand of α_Ⅴβ₃ integrin, was used to stimulate α_Ⅴβ₃ integrin signaling.

Our results demonstrated that oxymatrine effectively suppressed the viability of MDA-MB-231 and 4T1 breast cancer cells, and oxymatrine showed less cytotoxicity on normal breast mammary epithelial MCF-10A cells. In addition, oxymatrine reversed EMT in the MDA-MB-231 and 4T1 cells at nontoxic concentrations. Oxymatrine significantly inhibited cell migration and invasion, downregulated the expression of N-cadherin, vimentin, and Snail in MDA-MB-231 and 4T1 cells, but upregulated the expression of E-cadherin in 4T1 cells. The mechanism revealed that oxymatrine decreased the expression of α_Ⅴ and β₃ integrin and their co-localization. It also inhibited α_Ⅴβ₃ integrin downstream activation by suppressing the phosphorylation of FAK, PI3K, and Akt. Furthermore, oxymatrine prevented fibronectin-induced EMT and α_Ⅴβ₃ integrin/FAK/PI3K/Akt signaling activation.

Our results revealed that oxymatrine effectively reversed EMT in breast cancer cells by depressing α_Ⅴβ₃ integrin/FAK/PI3K/Akt signaling. Thus, oxymatrine could be a potential therapeutic candidate with anti-metastatic potential for the treatment of breast cancer.