Resveratrol inhibits LPS-induced epithelial-mesenchymal transition in mouse melanoma model

Epithelial to mesenchymal transition (EMT) has been linked to metastasis. Resveratrol exhibits potential antitumor activities; however, the inhibitory effects of resveratrol on the EMT of melanoma have not been demonstrated. Here, a new role for LPS in promoting EMT is described. LPS-induced EMT was identified by examining the markers of EMT. To assess the activation of NF-kappa B signal transduction pathway, we performed a reporter assay by using tumor cells transfected with the luciferase gene under the control of NF-kappa B response elements. The antitumor effects of resveratrol were evaluated in an experimental mouse metastasis tumor model. LPS increased N-cadherin and Snail expression and decreased zonula occludens-1 expression in a dose- and time-dependent manner. Meanwhile, LPS stimulated cell migration through activation of TLR4/NF-kappa B signal pathway. LPS-induced EMT is critical for inflammation-initiated metastasis. Nuclear translocation and transcriptional activity of p65 NF-kappa B, an important inducer of EMT, were inhibited by resveratrol. Resveratrol inhibited LPS-induced tumor migration and markers of EMT, significantly prolonged animal survival and reduced the tumor size. Thus, resveratrol plays an important role in the inhibition of LPS-induced EMT in mouse melanoma through the down-regulation of NF-kappa B activity. The data provide an insight into the mechanisms on the function of resveratrol during the processes of EMT.